Scipedia: Documents published in 2018

ATTRACkTIVE Advanced Travel Companion and Tracking Services

Scipedia content — Thu, 28 Jan 2021 17:40:52 +0100

Shift2Rail, a Joint Undertaking European initiative in the railway industry, is composed of five Innovation Programmes. Of these, the fourth one addresses “IT Solutions for Attractive Railway Services”. This Innovation Programme shall offer a seamless, stress-free, and even engaging experience for travelling. ATTRACkTIVE as one of the IP4 projects expands and further develops solutions of the prior lighthouse project IT2Rail in order to guide, support, inform, and potentially entertain users throughout their entire journey. It aims to provide new concepts, tools, and systems to improve the attractiveness of rail transport by offering more intuitive and engaging travel experience for travellers, while shielding them from the complexity and heterogeneity of services for door-to-door intermodal journeys. This includes disruption handling, navigation and user centric ubiquitous applications; as well as the required tooling and modular design of the system to foster adoption and to enable future refinements, new concepts, and ideas.

Methods to determine degradation in fuel cells

Scipedia content — Thu, 28 Jan 2021 17:35:35 +0100

Polymer electrolyte fuel cells are a promising technology for converting the chemically bound energy of hydrogen into power. In order to establish fuel cells as a commercially viable product, the durability of membranes and electrodes in practical applications such as electric vehicles needs to be extended. The degradation mechanisms over lifetime are investigated by subjecting fuel cells to accelerated stress tests. Decomposition of the polymer electrolyte significantly affects the ionic conductivity and therefore the fuel cell performance. Cracks and tears form due to the thinning of the membrane, leading to reactant crossover and fluoride emissions. Electrochemical methods for characterizing degradation include polarization curves, electrochemical impedance spectroscopy and hydrogen diffusion current measurements. Local effects like flooding and dry-out of fuel cells are investigated using impedance spectroscopy in combination with total harmonic distortion analysis.

Network Analysis for Assessment of Road Safety on Rural Travel Time Information System

Scipedia content — Thu, 28 Jan 2021 17:35:24 +0100

One way of improving traffic performance are dynamic traffic control systems using modern Intelligent Transport"br" Systems (ITS) tools also on rural roads. Among ITS systems are those informing drivers about travel time (Travel"br" Time Information System) using variable message signs or information channels such as the Internet, GSM, and"br" GPS to reroute traffic. To assess their performance, in terms of reliability in the evaluation of safety all the elements"br" of the network has been taken into account. In this framework, the present research work reports an evaluation of"br" road safety on the road sections included in the Travel Time Information System (TTIS) on the example of"br" Intelligent Traffic Control System of the Podhale Region (ISSRRP) in Poland. The assessment of road safety has"br" been carried out considering the network level, calibrating separately crash prediction models for classes of"br" intersection and links. The specification of Regional and National road sections allowed the comparison of the"br" safety on alternative road sections with lower geometric parameters included in TTIS.

EuroCombis in Germany – "ecocombis" or "climate killers"?

Scipedia content — Thu, 28 Jan 2021 17:34:57 +0100

Since January 1, 2017, 25.25 m EuroCombis (ECs) with a maximum gross vehicle weight rating (GVWR) of 40 t"br" are allowed in German national freight transport on a specified part of the road network. This decision was based"br" on a field test of the potential risks of the EC operation that was carried out under the surveillance by the Federal"br" Highway Research Institute (BASt). However, the assessment mainly focused on safety concerns rather than on"br" environmental impacts. To gain additional insights on the climate effects related to the EC use, a dedicated study"br" was initiated by the state government of Baden-Württemberg and Daimler AG. In this paper, we present the impact"br" of ECs on the modal split of national road and rail freight transport and the corresponding impact on greenhouse"br" gas (GHG) emissions. Analysis was carried out for a 2010 scenario mirroring the conditions of the field test and"br" for a 2030 scenario with a non-restricted highway network.

Faster coroutine pipelines: A reconstruction

Scipedia content — Thu, 28 Jan 2021 17:34:19 +0100

Spivey has recently presented a novel functional representation that supports the efficient composition, or merging, of coroutine pipelines for processing streams of data. This representation was inspired by Shivers and Might's three-continuation approach and is shown to be equivalent to a simple yet inefficient executable specification. Unfortunately, neither Shivers and Might's original work nor the equivalence proof sheds much light on the underlying principles allowing the derivation of this efficient representation from its specification. This paper gives the missing insight by reconstructing a systematic derivation in terms of known transformation steps from the simple specification to the efficient representation. This derivation sheds light on the limitations of the representation and on its applicability to other settings. In particular, it has enabled us to obtain a similar representation for pipes featuring two-way communication, similar to the Haskell pipes library. Our benchmarks confirm that this two-way representation retains the same improved performance characteristics. ispartof: pages:133-149 ispartof: Lecture Notes in Computer Science vol:11372 pages:133-149 ispartof: PADL 2019 - 21st International Symposium on Practical Aspects of Declarative Languages location:Cascais/Lisbon, Portugal date:14 Jan - 15 Jan 2019 status: Published online

Evaluation of Human Acceptance and Comfort of Automated Highway Driving at Different Levels of Automation

Scipedia content — Thu, 28 Jan 2021 17:34:09 +0100

Fully automated driving of road vehicles on highways consists of different vehicle control tasks that are currently evolving from research to series production. These tasks are mainly covered by the three following driving systems: Adaptive Cruise Control – ACC, Lane Keeping Assist – LKA and Lane Change Assist - LCA. Among these systems, different levels of automation are available, e.g. warning/informing, intervene on demand and also partially automated systems. This research presents the first part of a feasibility study about an intuitive switching mechanism using a Human-Machine Interface (HMI) that combines aforementioned systems in order to adjust the level of automation of SAE levels 0 to 3, (Smith 2013), according to the preferences of a human driver. Driving systems of the levels 0, 2 and 3 together with a novel HMI concept are implemented in a driving simulator and tested with respect to acceptance and comfort as well as to reliability by a sample of 20 volunteer drivers. The proof of concept of each system as well as the testing form the basis for a later implementation of the presented intuitive switching mechanism.

Travel time estimation on urban street segment

Scipedia content — Thu, 28 Jan 2021 17:33:57 +0100

Level of service (LOS) is used as the main indicator of transport quality on urban roads and it is estimated based on the travel speed. The main objective of this study is to determine which of the existing models for travel speed calculation is most suitable for local conditions. The study uses actual data gathered in travel time survey on urban streets, recorded by applying second by second GPS data. The survey is limited to traffic flow in saturated conditions. The RMSE method (Root Mean Square Error) is used for research results comparison with relevant models: Akcelik, HCM (Highway Capacity Manual), Singapore model and modified BPR (the Bureau of Public Roads) function (Dowling - Skabardonis). The lowest deviation in local conditions for urban streets with standardized intersection distance (400-500 m) is demonstrated by Akcelik model. However, for streets with lower signal density (<1 signal/km) the correlation between speed and degree of saturation is best presented by HCM and Singapore model. According to test results, Akcelik model was adopted for travel speed estimation which can be the basis for determining the level of service in urban streets with standardized intersection distance and coordinated signal timing under local conditions.

LIFE Project: Implementing a modelling framework for emergency vehicles advanced priority strategies

Scipedia content — Thu, 28 Jan 2021 17:33:35 +0100

Given the aging demographics and rapid urbanisation, cities need to be equipped to respond to emergency (eg. 999"br" calls) more quickly. By 2050, over 25% of the UK’s population will be over 65. This has implications on the"br" overall health services as well as the NHS Trust to cope with anticipated rise in ambulance call outs amidst"br" worsening urban congestion. Ambulance services are required to reach 75% of emergency calls within 8 minutes."br" For this reason, there is a growing need to develop new and innovative applications for an even more intelligent"br" use of the existing transport system that will support in real-time emergency vehicles to reach life threatening"br" emergency cases quicker."br" this paper will discuss the methodology and the preliminary results of the modelling framework implementation"br" of a “Life First Emergency Traffic Control” or “LiFE” system, a ITS implementation seeking to identify the best"br" solution to reduce the time to respond to emergency calls, whilst operating a resilient service with a cost and fuelefficient"br" fleet. Results of the application of a microsimulation model to replicate the behaviour of ambulances in"br" urban area and how different reactions of general traffic can impact on the travel time of an ambulance are"br" presented. The proposed microsimulation modelling framework has been developed with the final aim to"br" understand and evaluate the impacts and the best scenarios to improve ambulance (or any Emergency vehicle)"br" response time and gains in cost-saving, whilst assessing mitigation strategies to reduce other impacts such as"br" residual congestion."br" The work is part of an Innovate UK collaborative funded project, namely Life First Emergency Traffic Control"br" (LiFE) with the aim to develop an innovative application for an intelligent transport system that operates in realtime"br" to enable ambulances to reach life threatening emergency cases quicker by integrating ambulance route finder"br" applications with traffic management systems.

Development of Agent-Based CPS for Smart Parking Systems

Scipedia content — Thu, 28 Jan 2021 17:30:58 +0100

The increase volume of vehicles circulating in large cities and the limited space for parking are factors that motivate the adoption of systems capable of dealing with such problems. In this context, smart parking systems are suitable solutions to avoid the traffic congestion, the air pollution and the long search to find a free parking spot. The inclusion of emergent ICT technologies and artificial intelligence techniques, and particularly using multi-agent systems, combined under the scope of Cyber-Physical Systems (CPS), ensure flexibility, modularity, adaptability and the decentralization of intelligence through autonomous, cooperative and proactive entities. Such smart parking systems can be easily adapted to any type of vehicle to be parked and scalable in terms of the number of parking spots and drivers/vehicles. A fundamental issue in these agent-based CPS parking systems is the interconnection between the cyber and physical counterparts, i.e. between the software agents and the physical asset controllers to access the parking spots. This paper focuses on developing an agent-based CPS for a smart parking system and particularly addressing how the software agents are interconnected with the physical asset controllers using proper Internet of Things technologies. The proposed approach was implemented in two distinct parking systems, one for bicycles and another for cars, showing an efficient, modular, adaptable and scalable operation. info:eu-repo/semantics/publishedVersion

Estimating a light commercial vehicle OD matrix based on the vehicle tracking data of heavy good vehicles

Scipedia content — Thu, 28 Jan 2021 17:29:19 +0100

Light commercial vehicle (LCV) is one of the most dynamically developing vehicle categories, but,"br" unfortunately, there is a general lack of data on LCVs. Perhaps this is the reason behind the traditional traffic"br" modelling practice that LCVs are treated as automobiles and included in the passenger car Origin Destination"br" (OD) matrix, which may lead to false outcomes. We had a sample LCV OD database with 2800 records which"br" describes some specific travel patterns, but there were no data on the production and attraction of the settlements."br" In the development of the heavy good vehicles (HGV) matrix, significant methodological innovations were made"br" to build it exclusively on big data. The database contained vehicle tracking data of approximately 46% of the"br" heavy good vehicles on the roads of Hungary. The idea was, however, to find a quantifiable link between the"br" traffic of HGVs and LCVs. On the basis of this connection, LCV productions and attractions of the settlements"br" were estimated and with the help of the sample LCV OD database a good quality national LCV matrix was"br" created.

Aircraft position determination in SBAS system in air transport

Scipedia content — Thu, 28 Jan 2021 17:25:24 +0100

Analysis of artificial intelligence-based metaheuristic algorithm for MPLS network optimization

Scipedia content — Thu, 28 Jan 2021 17:22:24 +0100

Multiprotocol label switched (MPLS) networks were introduced to enhance the network`s service provisioning and optimize its performance using multiple protocols along with label switched based networking technique. With the addition of traffic engineering entity in MPLS domain, there is a massive increase in the networks resource management capability with better quality of services (QoS) provisioning for end users. Routing protocols play an important role in MPLS networks for network traffic management, which uses exact and approximate algorithms. There are number of artificial intelligence-based optimization algorithms which can be used for the optimization of traffic engineering in MPLS networks. The paper presents an optimization model for MPLS networks and proposed dolphin-echolocation algorithm (DEA) for optimal path computation. For Network with different nodes, both algorithms performance has been investigated to study their convergence towards the production of optimal solutions. Furthermore, the DEA algorithm will be compared with the bat algorithm to examine their performance in MPLS network optimization. Various parameters such as mean, minimum /optimal fitness function values and standard deviation.

Document type: Conference object

The impact of roadside advertising on safe driving behaviour in cities: A driving simulator approach

Scipedia content — Thu, 28 Jan 2021 17:21:56 +0100

The roadside billboards, as a distractor, seem to have been investigated and efforts have been made in order to"br" determine the extent to which they affect the safe driving behaviour. Most studies suggest that the existence of"br" roadside advertising billboards, in general, alters drivers’ behaviour, but they are quite ambiguous in quantifying"br" this impact. This research aims to investigate and quantify this effect by means of driving simulator experiment"br" including 31 young participants. The experimental procedure included driving in urban environment in high and"br" low traffic conditions, with or without advertising billboards on the roadside, while unexpected events were"br" designed to take place. Regression statistical modelling techniques were developed in order to investigate the"br" impact of roadside advertising on several driving performance measures. The models' application indicated that"br" roadside advertising leads to slight decrease of the mean speed, but at the same time slight increase of the reaction"br" time and lateral position of the vehicle from the right borderline.

CoLiTec Software for the Astronomical Data Sets Processing

Scipedia content — Thu, 28 Jan 2021 17:13:30 +0100

Nowadays, quick technological progress provokes creation of a big amount of the information that can be fed in different forms. There are a lot of different fields of science that use high dimensional data sets to analyze them in their researching. So, we need the data pre-processing methods and data reduction models to simplify input data sets by reducing unnecessary information. The paper deals with an approach of CoLiTec (Collection Light Technology) software to process in automated mode the different types of astronomical information which is fed online in the form of data sets or streams. Also the benefits of an usage of the OnLine Data Analysis System (OLDAS) was described. OLDAS helps with solving of the following Data Mining problems, such as clustering, classification and identification.

The strategic foundation of transport infrastructure projects

Scipedia content — Thu, 28 Jan 2021 17:08:50 +0100

When developing infrastructure, public debate is often dominated by the opposition. Frequently, the conflict escalates when a project is already planned or the construction has already started. One potential way for tackling these problems is to improve the strategic foundation of transport infrastructure projects. Strategic environmental assessment (SEA) is one instrument for showing that a transport infrastructure projects is never an end in itself, but is essential to accomplish objectives from different policy fields. Taking the example of the SEA for the Airport link, this paper shows the importance of a broad evaluation framework for assessing infrastructure projects on a strategic level. This way, opinion leaders can be convinced of the plan or programme respectively of a possible follow-up project and can act as advocators. Strengthening the role of SEA as a strategic planning instrument can increase the quality of plans and programmes and subsequently of planning projects and disburden environmental impact assessment.

Who Is Going to Ride the Upcoming Metro in Qatar?

Scipedia content — Thu, 28 Jan 2021 17:07:51 +0100

Qatar is one of the fastest growing countries around the world, resulting in substantially high private vehicle usage as well as heavy traffic congestion. It is currently estimated that the private car usage is about 85% of total traffic, and the remaining 15% includes public buses, taxis, and company buses. In this study, a survey was conducted to identify the potential users demographics of the of the upcoming metro service. The study revealed that 77.8% of the population is planning to use the upcoming metro service. More male, young, and expatriates are willing to use the service. The results indicate the need for programs to attract more users, especially female, elderly, and local Qataris. Scopu

Time-Shared Execution of Realtime Computer Vision Pipelines by Dynamic Partial Reconfiguration

Scipedia content — Thu, 28 Jan 2021 17:01:07 +0100

This paper presents an FPGA runtime framework that demonstrates the feasibility of using dynamic partial reconfiguration (DPR) for time-sharing an FPGA by multiple realtime computer vision pipelines. The presented time-sharing runtime framework manages an FPGA fabric that can be round-robin time-shared by different pipelines at the time scale of individual frames. In this new use-case, the challenge is to achieve useful performance despite high reconfiguration time. The paper describes the basic runtime support as well as four optimizations necessary to achieve realtime performance given the limitations of DPR on today's FPGAs. The paper provides a characterization of a working runtime framework prototype on a Xilinx ZC706 development board. The paper also reports the performance of realtime computer vision pipelines when time-shared.

Development of VISSIM generator based on OpenStreetMap

Scipedia content — Thu, 28 Jan 2021 17:00:31 +0100

VISSIM is a popular tool for traffic simulation. Before the simulation can be started, a model of the road network must be created which is a mostly manual and therefore tedious and time-consuming process. We present a VISSIM model generator which reduces the time spend for this task considerably. The generator creates a VISSIM model from an OpenStreetMap (OSM) file, which can be used by engineers as a skeletal structure. It creates all links, connectors, desired speed decisions, reduced speed areas and vehicle routes in a chosen area. Then the engineers can directly start with the parameterization."br" The architecture of the generator is client server based. This means the user chooses in his browser an area on the OSM map. Then this information goes to the generator. Consecutively, the generator loads the map data from the OSM server and processes them to a VISSIM model, which the user can then download. To add more valuable information, the generator will be extended to include hold lines recognized on aerial images. The evaluation shows, that using the generator saves some hours to the users.

Changes in commuters travel behaviour after introducing highquality regional railway services

Scipedia content — Thu, 28 Jan 2021 17:00:00 +0100

Introduction of new public transport services or improvement of existing ones change trip patterns as well as"br" generate new trips. Scale of both, mode shift and induced trips, is often difficult to predict. It happens especially"br" when introduced services was not available before or quality change is significant. This kind of situation happened"br" in Małopolska region (Poland) after development of regional rapid railway connections. Based on revealed"br" preferences survey among new railway service passengers authors investigated dimension of mode shift and"br" induced trips. In particular trip length distribution was analysed. Key findings shown that new, fast and high quality"br" railway connection attracted passengers from other modes of transport and new passengers as well. Moreover trip"br" length distribution has not changed significantly, however essentials savings of travel time and cost were shown.

Climate Adaptation of Road Infrastructure – A comparison of the implementation of the CEDR ROADAPT and the FHWA Framework for Vulnerability Assessment in The Netherlands and Washington State

Scipedia content — Thu, 28 Jan 2021 16:58:19 +0100

Since 2014, the United States Federal Highway Administration (FHWA) and Rijkswaterstaat in The Netherlands"br" have worked together on the topic of infrastructure climate resilience. Currently they are implementing climate"br" change or extreme weather resilience tools for infrastructure projects. They are both applying the ROADAPT"br" framework (sponsored by CEDR) and the FHWA Climate Change Vulnerability Assessment Framework to"br" projects in their respective countries: the SR167 completion project near Tacoma, Washington and the Innova58"br" highway expansion project in The Netherlands. This paper presents a discussion of the frameworks, the tools, the"br" results of implementation, and shares perspectives the authors gained from using the tools to help future users"br" understand the strengths and weaknesses of the tools. Both sets of tools have a similar approach and generally"br" result in comparable outcomes. However, each tool has its specific qualities and applicability. The ideal tool is"br" different for each situation. Both frameworks require expert knowledge to implement and interpret the results.

Standardization in Sustainability Transitions : A Study on Stakeholder Attitudes and Power Relations During the Standardization Process in the Vehicle-to-Grid Ecosystem

Scipedia content — Tue, 26 Jan 2021 18:17:18 +0100

The electrification of the transportation sector plays an important role in the sustainability transition as successful electric vehicle (EV) integration allows for the reduction of CO2 emissions. Moreover, bidirectional capabilities of the EVs (vehicle-to-grid) further facilitate this transition by supporting the electricity grid while lowering the cost of ownership of EVs when revenues from grid-supporting services are split between stakeholders. Due to sustainability challenges facing several domains, fundamental transformation processes are needed to transition away from our current global energy system. However, with the strong inertia of the current system together with the sheer complexity and vexed interests during transitions, neither private markets nor government agencies seem likely to spur this transition on their own. Transitions are thus political processes, in which standards can play an important role since they point to the direction of the transition. This thesis investigates the role of standardization in sustainability transitions. The aim was to improve the understanding of the diverse stakeholder attitudes towards the standardization process of the communication protocol between the vehicle and its charging equipment. While exploring this topic, the thesis further aimed to investigate the power relations that govern the interactions and coordination efforts between the diverse stakeholders involved in the vehicle-to-grid (V2G) standardization processes. To achieve this, a qualitative study was conducted where two transcripts from the California Energy Commission, adding up to a total of 667 pages, were coded in a mixed inductive-deductive manner. In addition, as a complement, 13 expert interviews were conducted. The results showed that power was expressed by actors on (and between) all levels in the system. Mutual dependency was the most frequently expressed power relation among the actors. The mutual dependency was assumed to be widely present due to the interdependent nature between the components in the V2G system. The automotive manufacturers were observed to have a strong position in the vehicle-to-grid ecosystem and it was noted that other actors conformed with their political and/or economic goals. Another finding related to power was the sense of powerlessness and frustration expressed by actors on all levels, likely enabling the status quo to prevail. There was also clear frustration towards policymakers concerning the lack of policy direction and actors expressed the need for market signaling. The policymakers seemed to adhere to both disruptive innovations and the existing regime, causing uncertainty in policy decisions. The empirics also showed that the standardization discussions have little focus on competition between standards at this point of the transition. The debate seemed to rather be shaped by the conflict between advocates and opponents of standardization, where the opponents argued against standardization due to fear of prematurely mandating a single standard. Advocates dominated over opponents at this point of the transition and the communication standard, ISO 15118 seemed to have significant industry support. Automotive manufacturers were found to be the most vocal stakeholder group against standardization. Furthermore, the results highlighted the functions and features of standards commonly mentioned in the V2G standardization discussions, where compatibility, market signaling, and future proof features belonged to the most frequently mentioned. Elektrifieringen av transportsektorn spelar en central roll för omställningen till ett hållbart energisystem eftersom elbilar bidrar till minskade utsläpp av koldioxid. Bidirektionella laddningsmöjligheter (V2G) kan möjliggöra omställningen ytterligare genom att stötta svaga elnät på lokal nivå samtidigt som funktionen kan minska kostnaderna för att äga en elbil. Fundamentala omställningar krävs för att lösa de hållbarhetsutmaningar som flera industrier står inför men på grund av komplexiteten i dessa system kan varken privat eller offentlig sektor driva denna förändring på egen hand. Omställningsprocessen är en politisk process där standardisering kan spela en viktig roll eftersom de kan indikera vilken riktning omställningen rör sig mot. Den här uppsatsen undersöker därför standardiseringens roll i hållbarhetsomställningar. Syftet var att öka förståelsen av olika aktörers ståndpunkter i standardiseringsprocessen av kommunikationen mellan en elbil och dess laddstation. För att undersöka detta ämne granskades även maktförhållanden som genomsyrar en standardiseringsprocess. Detta gjordes genom kvalitativ kodning av två transkriberade diskussioner om standardisering från California Energy Commission vilka totalt uppgick till 667 sidor. Utöver detta hölls 13 intervjuer som komplement. Resultatet visade att makt utövades av aktörer på samtliga nivåer i systemet. Ett ömsesidigt beroende kunde identifieras mellan aktörerna. Detta antogs vara framträdande på grund av de beroendeförhållanden som uppstår sig då samtliga aktörer krävs för att ett V2G-system ska fungera. Vidare observerades att maktutövande som förstärker och reproducerar existerande strukturer och institutioner uttrycktes av många aktörer i V2G-ekosystemet. En annan observation var att biltillverkare verkar ha en stark position i V2G-ekosystemet och det noterades att andra aktörer anpassade sig efter deras politiska och/eller ekonomiska mål. Ett ytterligare resultat var att det fanns en känsla av maktlöshet och frustration på alla nivåer i systemet vilket bidrog till upplevelsen av status quo. Det fanns en tydlig frustration speciellt mot beslutsfattare vilken grundade sig i bristen på tydliga riktlinjer. Beslutsfattare verkade anpassa sig såväl mot disruptiv innovation som till den existerande regimen vilket orsakade passivitet och osäkerhet vid beslutsfattande. Eftersom ramverket Multi-Level Power-in-Transition som användes för analysen inte tar hänsyn till att beslutsfattare kan svara både mot dominanta och mer radikala makrotrender, modifierades ramverket något innan det appliceras på empirin. Vidare visade analysen att det inte pågår någon konkurrens mellan standarder i denna fas av omställningen, däremot identifierades en konflikt mellan förespråkare och motståndare till standardisering där motståndarna var oroliga över att det var för tidigt att ge mandat åt en enskild standard. Förespråkare dominerade över motståndare i denna fas av omställningen och kommunikationstandarden ISO 15118 verkade ha betydande stöd från industrin. Biltillverkare befanns vara de aktörer som till största grad motsatte sig standardisering. Resultaten gav ytterligare en inblick i de egenskaper hos standarder som vanligtvis nämndes i diskussioner om kommunikationsstandarder. Några av de egenskaper som regelbundet belystes som viktiga var kompatibilitet och att den bör vara framtidssäker. En ytterligare viktig funktion med standardisering ansågs vara att ge tydliga signaler till marknaden.

The welfare costs of traffic congestion in São Paulo Metropolitan Area

Scipedia content — Tue, 26 Jan 2021 18:15:06 +0100

This thesis presents new evidences of negative impacts of traffic congestion in São Paulo Metropolitan Area, indicating that the omission or retardation of policy to alleviate that charges society with a high cost. Besides that, we shed light on Waze application\\'s impacts, evidencing GPS-based participatory navigation is a key element of the traffic in the contemporary cities. Induced by the economic theory, one can see that traffic slowness derived from the general demand for automotive vehicles corresponds to a social cost. With the objective of translating this cost to monetary units, we developed an approach that matches the 2012 Origin-Destination survey to Google Maps data. An econometric travel mode choice model is estimated and through that we infer the Value of Time for trips. From counterfactual analysis for travel duration, we estimate the delays of the trips in relation to a hypothetic free flow situation. Joining the calculations, we estimate that 89% of the trips motivated by work in São Paulo are retarded by traffic frictions, generating an annual welfare cost that amounts to R$7.338 billions. Additionally, we analyze widespread Waze malfunctioning at 10/23/2017. Combining congestion data to the Value of Time, we estimate that the Waze bug approximatedely tripled the welfare costs in regards to a typical day, showing the magnitude of mass effects that a social navigation application is able to trigger. Esta dissertação traz novas evidências dos efeitos negativos do congestionamento do trânsito na Região Metropolitana de São Paulo, mostrando que a morosidade na implantação de soluções custa muito caro para a sociedade. Além disso, evidências empíricas dos impactos do aplicativo Waze são elucidadas, mostrando que a navegação participativa por meio de aparelhos com GPS não pode ser esquecida ao pensarmos o trânsito nas cidades contemporâneas. À luz da teoria econômica, é possível ver que a lentidão do trânsito proveniente da demanda coletiva por automóveis corresponde a um custo social. Para quantificar este custo em unidades monetárias, é desenvolvida uma abordagem que combina dados da Pesquisa de Mobilidade de 2012 com dados do Google Maps. Através de um modelo econométrico de escolha de modal de transporte, são inferidos os valores do tempo em viagem e, através da análise contrafactual da duração dos deslocamentos, é estimado o tempo de atraso das viagens em relação a uma situação hipotética de fluxo livre. Juntando os cálculos, é estimado que 89% das viagens motivadas por trabalho em São Paulo são atrasadas por fricções do tráfego, gerando um custo de bem-estar da ordem de R$7,338 bilhões por ano. Ademais, são analisados empiricamente os impactos de uma falha generalizada do Waze ocorrida em 23/10/2017. Combinando dados de congestionamento com os valores de tempo já inferidos, é estimado que a falha aproximadamente triplicou os custos de bem-estar em relação a um dia típico, dando magnitude aos efeitos de massa que um aplicativo de navegação social é capaz de provocar.

Technology-based improvements in final approach flight phase

Scipedia content — Tue, 26 Jan 2021 18:13:51 +0100

[SPA] El aumento del tráfico aéreo ha sido exponencial en las últimas décadas; pasando a ser la aviación comercial una pieza clave en el turismo, el transporte urgente de mercancías, los negocios, etc. Tal y como confirman las estadísticas a nivel mundial, la aviación comercial seguirá en aumento hasta límites que exijan una gestión adecuada al número de vuelos. Esta gestión será clave para mantener la seguridad operacional en niveles óptimos. Este hecho supone que las operaciones aéreas y su gestión deberán evolucionar hacia una implementación de la tecnología que permita su control y gestión conforme a los estándares de seguridad operacional, de tal forma que confirmen la aviación como uno de los medios de transporte más seguros. El uso de una tecnología obsoleta en la gestión de tráfico aéreo podría poner en riesgo la seguridad de las operaciones aéreas y, consecuentemente, su utilización como medio de transporte. La evolución de la tecnología ha sido un factor clave en la universalidad y avance de la aviación, tanto civil como militar. En poco más de 100 años se ha pasado de navegar con una brújula a disponer en la cabina de las aeronaves de sistemas de navegación que permiten el aterrizaje con visibilidad cero. Esta evolución se ha acentuado notablemente en los últimos años con la introducción del GPS y con la revisión de procedimientos de navegación. La introducción de la navegación por satélite añadido a una evolución notable de las características de vuelo de las aeronaves ha supuesto que la navegación pase a estar enfocada en la radio ayuda (VOR, NDB, etc) a estarlo en las propias características o performances de la aeronave. Este hecho se conoce como navegación basada en las características o prestaciones; PBN por sus siglas en inglés (Performance Based Navigation). La introducción de la navegación por satélite también ha supuesto que se implementen aproximaciones más precisas y fiables como lo son: aproximaciones GBAS (Ground based Augmerntation System), aproximación GLS (GBAS Instrumental Landing System), control ATS mediante mensajes trasmitidos por Data Link, etc. Además de las aproximaciones finales, también se han introducido procedimientos de navegación y conceptos de operación más precisos en cuanto a la navegación en zonas terminales y en ruta. El aumento de la precisión y el cambio del concepto de la operación ha supuesto una auténtica revolución a nivel mundial. Esto ha dado lugar a que se implementen espacios aéreos en los que se establecen diversos requisitos de navegación o performance, como es el caso de la navegación de área (RNAV) o la “Required Navigation Performance” (RNP). Diversos espacios aéreos regionales han sido protagonistas en la implementación de los nuevos conceptos de operación o CONOPS, como los son el SESAR y el NextGen. De hecho, en el espacio aéreo NextGen numerosas radio ayudas tradicionales (mayormente VOR) dejarán de emitir señal en 2021. Por este motivo, esta tesis dedica un capítulo entero a revisar el estado del arte de la navegación basada en las características (PBN) y sus derivadas como lo son el GBAS, el D-Link, etc. A pesar de este avance en la tecnología aplicada a la navegación, existen áreas de la seguridad operacional en la que dicha evolución no se ha implantado de una forma lógica. Esta falta de implementación supone que exista riesgo de incidentes y/o accidentes en fases del vuelo tan claves como el despegue o el aterrizaje. Teniendo en cuenta esta premisa, esta investigación está enfocada en las deficiencias de implantación de la tecnología en la fase de aproximación, tomando como ejemplo dos situaciones operacionales concretas: el impacto de pájaro en aproximación final y la aproximación frustrada. Existe numerosa literatura que demuestra que la seguridad aérea, para mitigar el riesgo ante estas ocurrencias, está basada en procedimientos de la era de la navegación basada en la radionavegación (VOR, TACAN) y no en la navegación por satélite. Esto ha dado lugar a que existan fallas o condiciones latentes en el área de la seguridad operacional, las cuales deben ser analizadas mediante los modelos de seguridad operacional. Con el objeto de disminuir los accidentes aéreos, los responsables de la seguridad operacional (ICAO, FSO, etc.) comenzaron a enfocar la seguridad aérea hacia un sistema transversal y de perspectiva, que abarca factores organizativos, técnicos y humanos. Como consecuencia de este tipo de enfoque se desarrollaron teorías de predicción e investigación de accidentes. Algunas de las teorías más relevantes e influyentes fueron: el “Operational Risk Management (ORM)”, el modelo del doctor J. Reason (el “Swiss cheese model”) y el modelo de las 5 MS (man, media, machine, misión y management por sus siglas en inglés). Estas nuevas doctrinas de la seguridad operacional, especialmente las 5 Ms, son la base de esta investigación, siendo el pilar de los capítulos de la tesis en los que se proponen nuevas herramientas y procedimientos para la gestión del riesgo. En este estudio, estos modelos de gestión de la seguridad operacional están enfocados en las fases de vuelo en las que es más posible que se produzca un accidente aéreo: la aproximación final. Desde el comienzo de la aviación, ha habido accidentes relacionados con las aves, especialmente en las fases más críticas del vuelo; el despegue y el aterrizaje. Dado que la proliferación de aves es difícil de controlar en zonas aeroportuarias, existe un paradigma de que el impacto de ave es simplemente una tendencia imparable. Ese paradigma es aún más retroalimentado cuando se consideran políticas ambientales que protegen a las aves, incluso si éstas son un peligro para la seguridad operacional. A pesar de esto, con la aparición e integración de los sistemas de radar aviar, la estimación de las futuras trayectorias de las aves es posible. En otras palabras, se puede conocer la posición de un ave en cualquier momento y predecir su futura posición. Por lo tanto, tal y como se describe en esta investigación, mitigar su incidencia en los accidentes aéreos también es posible. Esto es así ya que la probabilidad y la severidad de un impacto con ave se pueden evaluar e identificar varios minutos antes de que ocurra. Esto supone un claro avance en el campo de la mitigación del riesgo de las operaciones aéreas, que tendrá una gran relevancia en el futuro. La evaluación del peligro de impacto de ave (WHA, por sus siglas en inglés) es un elemento clave en esta investigación. Con la aparición y la integración de los sistemas de radar aviar, el riesgo impacto de ave se puede conocer varios minutos antes de que ocurra. Teniendo esto en cuenta, algunos procedimientos o protocolos de mitigación se han propuesto en esta tesis para mitigar el riesgo de accidente por impacto de ave. La mitigación consiste en el desarrollo de una metodología y su simulación en un entorno realista para la gestión en tiempo real de la evaluación de riesgos. Esta evaluación está basada en datos del radar aviar y los parámetros de vuelo de una aeronave en aproximación final. Así, la citada evaluación de riesgo puede desenlazar acciones o procedimientos, que si son realizados con tiempo suficiente pueden reducir significativamente el riesgo de un impacto de ave en la aproximación final. Considerando lo anterior, se ha desarrollado un modelo de estimación de riesgo que combina las trayectorias del ave y de la aeronave (basado en velocidad, altitud y rumbo), con objeto de determinar futuras aproximaciones o cruces de trayectoria, así como la velocidad, la energía cinética y el ángulo de un posible impacto. Para comprobar si el sistema de mitigación de riesgos es viable, se han estudiado escenarios de simulación para confirmar si las acciones de mitigación podrían implementarse considerando el tiempo de reacción, las características de las aeronaves y la cobertura del radar aviar. El método de evaluación de riesgos propuesto y las medidas de mitigación para reducir la probabilidad de un impacto de ave en las aeronaves son un enfoque sistemático y científico para mejorar la seguridad operacional en los aeropuertos. La presente propuesta presenta la novedad de que la mitigación de riesgos en zonas aeroportuarias se realiza aplicando tecnología existente pero no implementada hasta la fecha, pese a los estudios realizados en algunos aeropuertos. Esta propuesta podría ser clave para un incremento de la seguridad operacional y un ejemplo para futuras investigaciones en el campo de la mitigación del riesgo en la aproximación final. Por ejemplo, si durante la aproximación final un riesgo elevado de impacto con ave se detecta con la suficiente antelación, la aeronave podría realizar una aproximación frustrada para mitigar y/o evitar el riesgo. Por otro lado, los procedimientos actuales de aproximación frustrada consisten en vuelos extensos basados mayormente en radio-ayudas VOR y TACAN. En otras palabras, no están actualizados conforme a la tecnología actual. En la tesis se propone un nuevo procedimiento de aproximación frustrada basado en procedimientos de navegación según procedimientos PBN y la tecnología actual, que puede ser un hito y un ejemplo para el futuro procedimiento de aproximación frustrada. A pesar de la nueva tecnología, los procedimientos de aproximación frustrada no se han rediseñado correctamente ni se han implementado para reinyectar el tráfico en la aproximación final o en los segmentos intermedios. En el caso del aeropuerto de Málaga, una aeronave en aproximación frustrada podría volar más de 40 minutos para intentar de nuevo el aterrizaje. Esa situación es similar en aeropuertos internacionales de primera fila, como Barajas, Atlanta, y Múnich, etc. Por lo tanto, existe una deficiencia en la aproximación frustrada que afectan a áreas de elevado tráfico aéreo: áreas terminales, fases finales de aproximación, etc. En la mayoría de los casos, cuando una aeronave realiza una aproximación frustrada, emplea cerca de 30 minutos para volver a inyectarse en el tráfico estándar. Este hecho supone un problema de seguridad para la tripulación aérea, los controladores aéreos y otras aeronaves. En consecuencia, este hecho representa un riesgo para la gestión del tráfico y la seguridad operacional. Para mitigar lo anteriormente descrito, se ha sido desarrollado un nuevo procedimiento de aproximación frustrada; con el objeto de mitigar el riesgo que supone esta deficiencia, la cual podría derivar en una condición latente. Así pues, en esta tesis se propone un procedimiento para evitar problemas de seguridad y acelerar el tráfico en aproximación frustrada. Este procedimiento está basado en un estudio sistemático, en el que se ha creado un ambiente de simulación de aeronaves con parametrización real, utilizando técnicas de simulación que dotan al escenario de una ambientación real. La metodología se basa en una combinación de simulación, parametrización y uso de la tecnología de navegación actualmente disponible y que utilizan varias flotas en todo el mundo: el GBAS, ADS-B y el enlace de datos controlador-piloto (CPDL). En la simulación se introduce una calculadora automática de aproximación frustrada y un sistema de guía (ARS) para ayudar a la tripulación aérea y a los controladores aéreos a reinsertar la aeronave en la aproximación final cuando hay una aproximación frustrada en curso. Para validar el sistema, se ha creado un escenario con requisitos y procedimientos internacionales de la OACI. La carta de aproximación GBAS de Málaga se ha propuesto como el escenario de estudio, ya que abarca varios criterios importantes: la propia aproximación está basada en el GBAS, tiene una alta densidad de tráfico durante en verano y periodo vacacional, la aproximación frustrada no está diseñada teniendo en cuenta el GBAS y la geografía es en sí un desafío para desviar el tráfico en la aproximación frustrada. En resumen, esta investigación se basa en la aplicación de la doctrina de la seguridad operacional y la tecnología actual en la mitigación del riesgo en dos escenarios concretos: el impacto de pájaro ave en la aproximación final y la aproximación frustrada. Esta implementación supone un aumento significativo de la seguridad operacional en una fase tan crítica como la aproximación final. Además, es un ejemplo para futuras propuestas de mitigación de riesgos e investigaciones en situaciones análogas como lo puedan ser la congestión de tráfico, los abortos de ascenso, etc. [ENG] The increase in air traffic has been exponential in recent decades; turning to be the commercial aviation a key piece in the tourism, the urgent transport of merchandize, the businesses, etc. As confirmed by global statistics of the evolution of air traffic in recent years, commercial aviation will continue to increase to limits that require adequate management to maintain operational safety at optimum levels. This fact assumes that air operations and their management must evolve towards an implementation of the technology that allows their control and management in accordance with safety standards, in such a way that they will confirm aviation as one of the safest means of transport. The anchoring in the technology of previous decades could jeopardize the safety of air operations and, consequently, their use as a means of transport. The evolution of technology has been a key factor in the universality and advancement of aviation, both civil and military. In a little more than 100 years it has gone from navigating with a compass to having in the cabin of the aircraft navigation systems that allow the landing with zero visibility. This evolution has been significantly accentuated in recent years with the introduction of GPS and the revision of navigation procedures. This revision has led to the implementation of more accurate and reliable approaches such as GBAS, GLS, and ATS control through messages transmitted by Data Link. Despite the advancement of technology, there are areas of operational safety in which this evolution has not been implemented in a logical manner. This lack of implementation means that there is a risk of incidents and / or accidents in key phases of the flight, such as takeoff or landing. This research is focused on the deficiencies in the implementation of technology in the approach phase; taking as an explanatory example the bird strike and the missed approach. There is a large literature that shows that both situations are based on procedures of the era of navigation based on radio navigation (VOR, TACAN) and not on satellite navigation. This has resulted in faults or latent conditions in the area of safety. In order to reduce accidents, those responsible for safety (ICAO, FSO, etc.) began to focus on aviation safety towards a transversal and perspective system, which includes organizational, technical and human factors. Because of this type of approach, theories of prediction and investigation of accidents were developed. Some of the most relevant and influential theories were the Operational Risk Management (ORM), the J. Reason model, the “SHELL” model and the 5M system. These new doctrines of operational safety, especially the 5M, is the basis of this research, being the pillar of the chapters in which new tools and procedures for risk management are proposed. Since the beginning of aviation, there have been accidents related to birds, especially in the most critical phases of the flight; at takeoff and landing. Given that the proliferation of birds is difficult to control in airport zones, there is a paradigm that assumes that the bird impact is simply an unstoppable trend. This paradigm is even more reinforced when considering environmental policies that protect birds, even if they are a safety hazard for aviation. Despite this, with the emergence and integration of avian radar systems, the estimation of future trajectories of birds is possible. Therefore, as described in this investigation, mitigating its incidence in air accidents is also possible. This is so since the probability and severity of a bird impact can be assessed and identified several minutes before it occurs. This is a clear advance in the field of risk mitigation of air operations. The bird impact hazard assessment (WHA) is a key element of this investigation. With the emergence and integration of avian radar systems, the probability and severity of a bird impact can be assessed several minutes before it occurs. Thus, some mitigation procedures or protocols have been proposed in this thesis to mitigate the risk of accident. The mitigation consists of the development of a methodology in a realistic environment for the real-time management of the risk assessment based on avian radar data and the flight parameters of an aircraft on final approach. This risk assessment may involve actions or procedures, which will be carried out with enough time to significantly reduce the risk of a bird impact on the final approach. Considering the above, a risk estimation model has been developed that combines the trajectories of the bird and the aircraft (based on speed, altitude and heading), in order to determine future approaches or trajectory crossings, as well as the speed, the kinetic energy and the angle of a possible impact. In order to verify if the risk mitigation system is feasible, simulation scenarios have been studied to confirm if the mitigation actions could be implemented considering the reaction time, the characteristics of the aircraft and the coverage of the avian radar. The proposed risk assessment method and mitigation measures to reduce the likelihood of a bird impact on aircraft are a systematic and scientific approach to improve airport safety. This proposal presents the novelty that the mitigation of risks in airport zones is carried out applying existing technology but not implemented to date despite the studies carried out in some airports. This proposal could be key for an increase in safety and an example for future research in the field of mitigation of risk in the final approach. On the other hand, current missed approach procedures consist of long flights that are mainly based on the VOR and TACAN aids; in other words, they are not updated to the current technology. The thesis proposes a new procedure of missed approach based on navigation procedures according to PBN procedures and current technology that can be a milestone and an example for the future missed approach procedure. Despite the new technology, the missed approach procedures have not been properly designed or implemented to divert traffic to the final approach or intermediate segments. In the case of the Malaga airport, an aircraft on a missed approach could fly more than 40 minutes to land again. This situation is similar in relevant international airports, such as Barajas, Atlanta, and Munich. Therefore, there is a deficiency when considering the missed approach in highly dense traffic areas: terminal areas, final stages of approach, etc. In most cases, when an aircraft executes a missed approach, it takes about 30 minutes to rejoin standard traffic, which poses a safety problem for the aircrew, air traffic controllers and other aircraft. Consequently, this represents a risk for traffic management and safety. Considering the above described, a new procedure of missed approach has been developed to mitigate the risk posed by this deficiency, which could lead to a latent safety condition. In this thesis a procedure is proposed to avoid safety problems and accelerate traffic in missed approach. This procedure is based on a systematic study, in which a simulation environment has been created with aircraft with real parameterization, using simulation techniques that give the scenario a real atmosphere. The methodology is based on a combination of simulation, parameterization and use of currently available navigation technology, which are used by several fleets around the world: GBAS, ADS-B, and CPDL. An automatic missed approach calculator and a guidance system (ARS) is introduced to assist the aircrew and air traffic controllers in reinserting the aircraft into the final approach when a missed approach is in progress. To validate the system, a scenario with international ICAO requirements and procedures has been created. The GBAS Malaga approach chart has been proposed as the study scenario, since it covers several important criteria: the approach itself is based on GBAS, the airport has a high traffic density during summer and holiday period, the missed approach is not designed with GBAS in mind, and geography is itself a challenge to divert traffic on the missed approach. This research is based on the application of the doctrine of operational safety and current technology in risk mitigation in two specific scenarios: the impact of bird on the final approach and the missed approach. This implementation supposes a significant increase of the operational safety in a phase as critical as the final approach. In addition, it is an example for future proposals for risk mitigation and investigations in analogous situations such as traffic congestion, promotion abortions, etc. Escuela Internacional de Doctorado de la Universidad Politécnica de Cartagena Universidad Politécnica de Cartagena Programa de Doctorado en Tecnologías Industriales por la Universidad Politécnica de Cartagen

Sustainable transportation in a low to zero impact vehicle

Scipedia content — Tue, 26 Jan 2021 18:12:12 +0100

Estimation of aircraft performance from quick access recorder flight data

Scipedia content — Tue, 26 Jan 2021 18:11:27 +0100

Considering the expected air traffic growth, the innovation and development of new tools able to allow a more efficient and safer way of managing aircraft operations is necessary to achieve future expectations. In this context, it is important to be capable of accurately predict aircraft trajectories to ensure efficient aircraft operations (e.g., planning and dispatching of flights, in-flight trajectory prediction, etc.) as well as to make more robust the Air Traffic Management (ATM) system (which includes ground based systems for ATC, predicting demand in ATC sectors, etc). The way of predicting them is based on aircraft performance models (APM), i.e., sets of equations that allow to model the aircraft performance according to some specific coefficients that depend on the aircraft carrying out the flight. Therefore, the predicted trajectories accuracy will depend directly on the aircraft performance model used. If the APM does not reflect the reality, the predicted trajectories will not be accurate enough. Moreover, since these trajectories will not be longer optimal according to the real performance model, the performance in cost-efficiency and the environmental impact of aircraft operations will be decreased. Then, it is required the use of aircraft performance models as realistic as possible. The objective of this Master Thesis is the design of an algorithm capable to estimate the coefficients of the functions describing the aircraft performance model considered, which will be the Base of Aircraft Data (BADA), from Quick Access Recorder (QAR) flight data. The idea is to obtain the real coefficients values of each specific tail number aircraft to accurately model their performance for trajectory prediction purposes. To perform the coefficients' estimation, real flight data has been used, consisting in a set of trajectories carried out by more than 30 different tail number aircrafts and obtained from their respective QAR. Among these aircrafts, only one (i.e, its trajectories) will be selected to design the estimation algorithm, which consist in a nonlinear least squares optimization problem. The output will be the coefficients value that better fits to the QAR data used, i.e, that minimize the difference between the real trajectories and the generated predicted trajectories as a result of applying the estimated coefficient's value to the BADA model equations. The results show a good estimation accuracy for the four aircrafts analysed, obtaining a very low prediction error in all cases, which proves the reliability of the algorithm and the necessity of tailoring the existing performance models (in this case BADA).

PLANNING OF CHARGING INFRASTRUCTURE FOR ELECTRIC-DRIVE ROAD VEHICLES

Scipedia content — Tue, 26 Jan 2021 18:09:15 +0100

To deal with the massive deployment of electric vehicles, charging stations must be properly placed. This is an extremely important issue that must be resolved before many electric vehicles are manufactured and governmental authorities start adopting policies to initiate higher electromobility. A poor design of the charging infrastructure can cost a significant amount of resources and can disrupt the electric vehicle users’ convenience, can offer poor quality of service and other user dissatisfaction. A public charging location is defined as location in a road network, where any electric vehicle user can come to charge his battery. Due to various charging technologies, the charging service can be fulfilled by shorter or longer charging time depending on the power transfer capacity and the disposable charging time of the users. The charging station must be within the reachable driving range distance of the electric vehicles and must provide a charging service for majority of users at a lower cost and higher quality. In this dissertation, we present a new optimisation procedure for charging stations placement. The introduced methodology takes into account the electric vehicle users, the electric and road networks. The electric power system reliability check, quality of service and charging reliability of the charging infrastructure are used as optimisation criteria, while placing charging stations of different charging technology by minimal investment costs. Electric power system reliability check is incorporated in the optimisation constraints by using a DC model to calculate the power flows. In this part, the charging reliability criterion of the charging infrastructure is defined as selecting at least one candidate location within the driving range of the electric vehicles in order to ensure unlimited mobility. Another criterion is the quality of service required by the electric vehicle users, which considers the time the users are willing to spend for charging their battery, when traveling, to complete the trip. To please the requirements of the users regarding the quality of service of the charging infrastructure, different charging technology types are factored in the optimisation objective function. The optimisation model also includes the mobility behaviour of electric vehicles by involving their trajectories of movement at different time instances. By also analysing their mobility behaviour, the traffic load of the candidate locations is identified which exposes the number of electric vehicles that are going through a particular candidate location. The final optimal charging infrastructure expansion plan shows the optimal placement layout, number of locations and placement cost. We also elaborate a stochastic formulation of the optimisation placement procedure that takes into consideration the stochastic occurrences that can have a significant impact on the electric vehicles’ driving range i.e. battery charge, the charging time that the users are willing to spend while charging at candidate location and the charging stations’ investment costs. The stochastic formulation includes also a representative trajectories search and a scenario reduction method to form common stochastic scenarios to be executed by the proposed optimisation model. Besides the charging infrastructure placement plan, the optimal results of the stochastic scenarios can be used to calculate the placement probability of candidate locations, which is fundamental for the charging infrastructure planners in the decision-making part. The numeric results illustrate the application of the proposed charging infrastructure optimization on test road and electric power system by showing the optimal charging stations placement layout and overall placement costs for the optimization constraints set on the charging reliability, required quality of service and running a power system reliability check. Additionally, for the stochastic formulation of the optimization model, the results show the optimal charging locations and their placement probability, which exposes their importance to charging infrastructure planners in terms of prioritization and robust decision-making. For the detailed analysis made on the impact of the stochastic driving range scenarios on the optimization output regarding the placement cost and locations, it is ascertained that a shorter uncertainty distance increases the number of candidate locations included in the charging reliability criterion resulting in higher overall charging infrastructure placement costs and vice-versa. Za masovno vpeljavo električnih vozil morajo biti polnilne postaje skozi postopke načrtovanja polnilne infrastrukture lokacijsko pravilno razporejene s ciljem zagotoviti zanesljivo oskrbo z električno energijo, potrebno v prometu. To je izredno pomembna naloga, ki jo je treba opraviti, preden se poveča številno električnih vozil in preden vladini organi začnejo sprejemati politične odločitve za večjo elektromobilnost. Slabo zasnovana infrastruktura za električna vozila lahko zviša stroške za polnjenje električnih vozil, vpliva na samo udobje uporabnikov električnih vozil, kakovost storitve polnjenja in povzroči dodatna nezadovoljstva uporabnikov. Torej je pravilno (optimalno) postavljena polnilna infrastruktura bistvenega pomena za povečanje množične uporabe in večjo uporabnost električnih vozil. To je velik izziv, ki vključuje zasnovo in uvedbo omrežij javnih (in zasebnih) polnilnih postaj s skupnimi povezanimi sistemi za preverjanje pristnosti in zaračunavanja stroška porabljene električne energije. Javna polnilnica je opredeljena kot polnilnica v cestnem omrežju, kjer lahko vsak imetnik električnega vozila pride in napolni svojo baterijo. Zaradi različnih tehnologij polnjenja je mogoče storitev polnjenja opraviti v krajšem ali daljšem časovnem obdobju, glede na zmogljivost polnilnic in razpoložljiv čas polnjenja uporabnikov. Polnilnice morajo biti postavljene v dosegljivi razdalji električnih vozil in morajo zagotavljati storitve polnjenja za večino uporabnikov z visoko kakovostjo storitve polnjenja, ki je povezana z razpoložljivim časom polnjenja vozil. Čas, potreben za polnjenje baterije, je odvisen od treh glavnih dejavnikov: priključne moči polnilnice, zmogljivosti baterije in stanja napolnjenosti baterije ob času polnjenja. Priključitev polnilnice na omrežje in vrsta priključka se določi na podlagi uvrstitve v skupino končnih odjemalcev glede potrebe po energiji, moči in tipu priključka. Pri tem je operater polnilne infrastrukture dolžan izvesti vse ukrepe, ki jih predpisujejo sistemska obratovalna navodila. Zmogljivost baterije je različna v odvisnosti od tehnologije shranjevanja, tipa električnega vozila (avto, tovornjak, avtobus, moped, tricikel), izvedbe modela, električnega motorja, napetosti baterije, stopnje hitrosti polnjenja / praznjenja itd. Za polnjenje baterij električnih vozil so na voljo različne tehnologije polnjenja, vendar trenutno obratujejo trije standardni nivoji polnjenja, in sicer: • prvi nivo polnjenja se nanaša na uporabo enofaznega izmeničnega sistema do 3 kW priključne polnilne moči (običajno je 1 kW). Odvisno od lastnosti in tehnologije shranjevanja baterije je lahko čas polnjenja do 24 ur - drugi nivo polnjenja uporablja trifazni izmenični sistem, pri čemer je priključna moč do 24 kW. Čas polnjenja je do 8 ur. Zahteva tudi dodatne dogovore z operaterji omrežja glede nastavitev zaščite in inštalacije dodatne opreme, ki jo je treba namestiti k polnilnici (transformatorji, odklopniki, stikala, adapterji itd.) - tretji nivo polnjenja predstavlja hitro polnitev. Priključna moč polnjenja je v razponu od 44 kW do 240 kW. Hitro polnjenje lahko popolnoma napolni baterijo električnega - vozila v 15 min - 30 min, kar je relativno primerljivo s časom polnjenja rezervoarja vozila z motorjem z notranjim zgorevanjem. Tretje nivo zahteva povezavo na višji napetostni nivo in je postavitev takega polnilnega sistema bolj zahtevna v primerjavi z nivojema 1 in 2, ker je treba namestiti dodatno električno opremo višjega napetostnega nivoja. Izkazalo se je, da je večina uporabnikov električnih vozil zadržanih do dejstva, da nimajo dovolj polnilnih postaj na poti do končne destinacije, kar pomeni, da uporabniki zaradi neprimerno načrtovane polnilne infrastrukture ne bodo dosegli cilja. Ocenjuje se, da je s trenutno tehnologijo mogoče avtonomno na električni pogon prevoziti do 350 km z enim polnjenjem, vendar je tipična dnevna razdalja nekje do 80 km na dan. Cilj proizvajalcev električnih vozil za prihodnja leta je razvoj in zagon množične proizvodnje električnih vozil s tehnologijami shranjevanja električne energije, ki bodo omogočile potovanje na daljše razdalje, primerljive s temi, ki jih danes dosegajo vozila z motorji z notranjim izgorevanjem, tudi do 1000 km in več. Trenutno so poti na daljše razdalje težavne, saj so na razpolago le javne polnilnice. V nekaterih primerih vozniki potujejo dlje časa in prevozijo daljše razdalje, da bi našli polnilnico. Dejstvo je, da morajo biti polnilnice postavljene na lokacijah, ki so primerne za uporabnike električnih vozil, na primer na lokacijah, kjer se beleži večji promet z električnimi vozili. Kot drugo, ob prihodu je lahko polnilnica zasedena, zato morajo vozniki čakati na vrsto, da napolnijo baterije. Ta scenarij je zelo realen, saj se s trenutno tehnologijo shranjevanja električne energije električna vozila polnijo dlje časa, kar povzroča daljše čakalne vrste, še posebej ob povečanem številu električnih vozil v prometu. Z daljšimi čakalnimi vrstami so nadalje povezane tudi zahteve po večjem prostoru na črpališčih, počivališčih, kjerkoli se pač nahajajo polnilnice. Naključna postavitev polnilnic je med glavninami ovirami za splošno sprejetje in s tem uporabnost električnih vozil, saj s tem se lahko poveča neudobnost in nezadovoljstvo voznikov. Poudariti je treba, da se morajo polnilnice postavljati na primernih lokacijah. Gre za večrazsežnosti problem: tehnični – priključitev na omrežje, obremenitev omrežja, drugi vplivi na obratovanje omrežja itd., ekonomski – stroški priključitve, stroški vzdrževanja in obratovanja itd. in družbeni – dostopnost polnilnic, udobje voznikov itd. Izzivi, ki se odpirajo na področju načrtovanja elektroenergetskih in polnilnih omrežij s povečanim deležem električnih vozil, so torej tako tehnične, ekonomske kot tudi družbene narave. V tej doktorski disertaciji smo razvili nov matematičen postopek za optimalno načrtovanje izgradnje polnilne infrastrukture za električna vozila. Predlagana metodologija upošteva obnašanje uporabnikov električnih vozil (vozne navade), tehnologijo polnjenja ter obstoječo cestno infrastrukturo in dostopnost elektroenergetskega sistema. Preverjanje zanesljivosti elektroenergetskega sistema, kakovosti storitve polnjenja in zanesljivost polnilne infrastrukture se uporabljajo kot omejitve v predlaganem optimizacijskem modelu, pri čemer se polnilnice postavljajo na izbranih optimalnih lokacijah glede na tehnologijo polnjena z minimalnimi naložbenimi stroški inštalacije, vzdrževanja, obratovanja. Preverjanje zanesljivosti elektroenergetskega sistema je vključeno v optimizacijske omejitve z uporabo DC (enosmerni izračun) metode izračuna pretokov moči. Z DC načinom izračuna pretokov moči preverjamo obremenitev vodov zaradi vključitve polnilnic ter bilanco v sistemu. Pri optimizaciji je merilo zanesljivosti polnjenja polnilne infrastrukture opredeljeno kot izbor vsaj ene možne lokacije v območju dosega vožnje električnih vozil, s ciljem zagotavljanja neomejene mobilnosti – da je v območju dosega vsaj ena polnilnica in to v smeri poti. Drugo merilo je kakovost storitve polnjenja, ki jo zahtevajo uporabniki električnih vozil. Ta upošteva čas, ki so ga uporabniki pripravljeni nameniti polnjenju baterije med potovanjem, da bi lahko prispeli na cilj. S tem želimo približati model čim bližje realnosti, realnost pa je, da imamo več polnilnih tehnologij, v grobem 2 skupini - hitre in počasne. Optimizacijski model vključuje tudi vozne navade voznikov električnih vozil z vključevanjem njihovih voznih poti v različnih časovnih obdobjih. Z analizo njihovega vedenja se določi prometna obremenitev lokacij, kar je bistvenega pomena pri sprejemanju odločitve o primernosti izbrane lokacije glede postavite polnilnic in njihovih priključnih moči. Priprava vhodnih podatkov vključuje pripravo modelov električnih in cestnih omrežij, niz tehnologij in naložbenih stroškov inštalacije, vzdrževanja in obratovanja, trajektorij gibanja električnih vozil in zahtevano raven kakovosti storitve polnjenja. Da bi modelirali cestno omrežje ter da bi opazovali obnašanje voznikov električnih vozil, uporabljamo postopek razdelitev na odseke z oblikovanjem diskretnih množic cestnega omrežja in trajektorij. Uporabljamo diskretni način, kar pomeni, da sta cestna infrastruktura in trajektorije premikanja voznikov električnih vozil modelirana z množicami diskretnih elementov. Pri električnih vozilih je njihov doseg glavnega pomena zaradi zagotovitev neomejene mobilnosti, zato je pri določanju lokacij polnilnic doseg električnega vozila glavni dejavnik pri oblikovanju kriterija polnilne zanesljivosti polnilne infrastrukture. V nadaljnjih poglavjih je bolj podrobno predstavljen koncept, s katerim se postavi kriterij oblikovanja polnilne zanesljivosti polnilne infrastrukture. Pri postopku optimizacije se upošteva tudi pomembnost lokacije na način, da se ji na podlagi analize prometne obremenjenosti dodeli ustrezna utež. Posledično imajo lokacije z večjimi utežmi večjo pomembnost v postopku optimizacije izbor lokacij polnilnic, saj večja utež pomeni, da večje število električnih vozil prepotuje to lokacijo. Ob pripravi podatkov se tudi upošteva več vrst tehnologij polnjenja. Vsaka tehnologija polnjenja ima svojo moč, ki vpliva na čas polnjenja. Tehnologije večjih priključnih moči (tehnologije hitrega polnjenja), imajo primerljiv čas polnjenja z konvencionalnimi načini polnjenja vozil z notranjim izgorevanjem. V tej doktorski nalogi pri pripravi podatkov in v postopku optimizacije podajamo bolj podroben pregled polnilih tehnologij. Vsaka lokacija cestnega omrežja, odvisno od možnosti povezave in izvedbe, ima različen naložbeni strošek inštalacije, vzdrževanja in obratovanja, ki ga upoštevamo v kriterijski funkciji pri postopku optimizacije. Zahtevana kakovost storitve polnjenja vključuje razpoložljiv čas, ki bi ga vozniki električnih vozil namenili polnjenju na poti do svojega končnega cilja. V tej doktorski nalogi podrobno opisujemo in dajemo definicijo kakovosti storitve polnjenja, s katero tudi vplivamo na končno razporeditev lokacij polnilnic v cestnem omrežju. Zaradi vključitve novih polnilnic z različnimi moči polnjenja in zaradi omejitve virov električne energije in prenosa vodov v elektroenergetskem sistemu, je vključen izračun prerokov moči na podlagi DC metode. V naslednjih letih je pričakovati povečan vpliv obratovanja polnilnic zanesljivosti elektroenergetskega sistema zaradi množičnega vključevanja električnih vozil. S predlaganim postopkom optimizacije postavitve polnilnic bodo lahko načrtovalci polnilne infrastrukture in operaterji elektroenergetskih omrežjih uskladili delovanje in se dogovorili za širitev omrežij, kar ima za posledico zanesljivo oskrbo z električno energijo. Končni načrt optimalne postavitve polnilne infrastrukture prikazuje optimalno razporeditev postavitve, število lokacij in naložbeni strošek postavitve polnilne infrastrukture. V tej disertaciji smo obravnavali tudi razširitev postopka optimizacije s stohastično formulacijo, saj je večina vhodnih parametrov povezani z negotovostjo, ki lahko močno vpliva na optimalno postavitev polnilnic. Ker je znanje o prihodnjih vrednostih vhodnih parametrov pogosto neznano ali je znano le v času faze načrtovanja, je vključitev stohastične komponente smiselna za dolgoročno načrtovanje polnilne infrastrukture. Negotovost se lahko razvrsti v dve kategoriji: naključna in nenaključna negotovost. Ta disertacija je osredotočena na naključne negotovosti, za katere so značilni ponovljivi parametri z določenimi odstopanji in omogočajo možnost statistične analize, ki poda funkcijo porazdelitve verjetnosti, povprečne vrednosti, standardne odklone itd. Nenaključne negotovosti z nejasnimi podatki v stohastični formulaciji niso upoštevani. Glavna motivacija za razširitev postopka optimizacije s stohastično formulacijo je vključitev stohastične narave obnašanja električnih vozil, njihovega dosega, razpoložljivega časa namenjenega polnjenju baterije električnih vozil in naložbenih stroškov inštalacije, vzdrževanja in obratovanja za različne tehnologije polnjenja. S pomočjo stohastičnega modeliranja bomo lažje razumeli vplive na optimalno izbiro lokacij in postavitev polnilnic in s tem povezanimi stroški, hkrati pa se bolj približali k dejanskim dogodkom, ki so v realnosti navezani na elemente, kar je cilj stohastičnega modeliranja. Zagotovo morajo biti optimalne lokacije polnilnic postavljene na mestih, kjer se odvija največ prometa. Zato je treba vse negotovosti, povezane s odmikom od najpogosteje vožene trajektorije vključiti v postopek optimalne postavitve polnilnic. Negotovi dejavniki, kot so hitrost vožnje, pospešek, masa in aerodinamika električnega močno vplivajo na doseg električnega vozila. Stohastično modeliranje kakovosti storitve polnjenja, QoS (angl. Quality of Service), zajema vse stohastične dogodke v realnem času, ki vplivajo na razpoložljivi čas polnjenja voznikov električnih vozil, kot so delno napolnjene baterije, prometne razmere na cestah itd. Pri naložbenih stroških inštalacije, vzdrževanja in obratovanja za različne tehnologije polnjenja se stohastična komponenta uvede s ciljem, da se zajame negotovost, ki je posledica neprekinjenega razvoja baterij različnih proizvajalcev, ki pa ponujajo izdelke/storitve po določeni ceni. Stohastična komponenta prav tako pokriva negotovosti povezane z inflacijo in diskontnimi stopnjami naložbenih stroškov za različne vrste tehnologij polnjenja. Nadgraditev oz. razširitev determinističnega postopka optimizacije postavitve polnilnic s stohastično formulacijo zagotavlja koristi načrtovalcem polnilnih infrastruktur, kot so prednostni seznam optimalnih lokacij za postavitev polnilnic različnih tehnologij polnjenja z minimalnimi naložbenimi stroški inštalacije, vzdrževanja in obratovanja, ki se razvrščajo po svoji verjetnosti izbire lokacije, verjetnosti dogajanja, številu lokacij, njihovih postavitvah v prostoru in skupnem strošku postavitve. Stohastična formulacija postopka vključuje novo metodo iskanja reprezentativne poti električnih vozil. Pri tem smo predlagali novi kazalnik TSI (angl. Trajectory Similarity Index), s katerim se določa podobnost med stohastičnimi trajektorijami električnih vozil, ne glede le na dolžine trajektorij, ampak z njihovimi časovno-prostorskimi lastnosti. S pomočjo novega kazalnika TSI smo predlagali rešitev, s katero se določa reprezentativne trajektorije gibanja električnih vozil, ki so v nadaljevanju vključene v optimizacijski postopek. Pri stohastični formulaciji smo uporabili tudi metodo za zmanjšanje števila scenarijev s ciljem poenostavitve kompleksnosti samega optimizacijskega postopka. Na razpolago je več optimizacijskih metod, kot so: GA (angl. Genetic Algorithms), ANN (angl. Artifitaial Neural Networks), LP (angl. Linear Programming), MILP (angl. Mixed Integer Programming), AI (angl. Artifitial Intelegence), itd. V tej doktorski disertaciji uporabljamo optimizacijski postopek MILP, zaradi enostavnosti, hitrosti in ustreznosti reševanja zastavljenega matematičnega optimizacijskega modela pri izbiri optimalne lokacije postavitve polnilnic. Rezultate prikazujejo uporabnost novega matematičnega postopka za optimalno načrtovanje izgradnje polnilne infrastrukture za električna vozila, pri čemer sta uporabljeni cestno in električno testno omrežje. Prikazane so optimalne lokacije in skupni najmanjši strošek izgradnje, obratovanja in vzdrževanja glede na tehnologijo polnjenja ob upoštevanju omejitev optimizacije, kot so zanesljivost polnilne infrastrukture, zahtevana kakovost storitve polnjenja in preverbo zanesljivosti elektroenergetskega sistema. V rezultatih razširjenega optimizacijskega modela s stohastično komponento je tudi prikazan prednosti seznam optimalnih lokacij za postavitev polnilnic različnih tehnologij, ki se razvrščajo po svoji verjetnosti izbire lokacije. Rezultati zajamejo tudi natančnejšo analizo negotovosti dosega električnega vozila in scenarije vpliva na optimizacijo izbire lokacij in skupnim stroškom postavitve. Med glavnimi izvirnimi prispevki doktorske disertacije so: nov večkriterijski matematičen postopek za optimalno načrtovanje izgradnje polnilne infrastrukture za električna vozila nov kriterij, ki definira zanesljivost polnjenja (angl. Charging Reliablity) polnilne infrastrukture s ciljem zagotavljanja neomejene mobilnosti električnih vozil kriterij preverjanja zanesljivosti obratovanja električnega omrežja nov kriterij kakovosti storitve polnjenja polnilne infrastrukture (angl. Quality of Service) na podlagi zahteve uporabnikov električnih vozil glede njihovega razpoložljivega časa za polnjenje baterij in glede na trenutno stanje baterije razširitev predlaganega optimizacijskega model s stohastično komponento. Cilj je zajeti vse negotovosti povezane z vhodnimi podatki (obnašanje voznikov, domet električnega vozila, razpoložljivi čas polnjenja baterije električnega vozila in stroški izgradnje, obratovanja in vzdrževanja glede na tip polnilne tehnologije).

Battery supported charging infrastructure for electric vehicles : And its impact on the overall electricity infrastructure

Scipedia content — Tue, 26 Jan 2021 18:04:56 +0100

The Paris Agreement was formed in 2015 to reduce the environmental impact and limit the increase in temperature to 2°C compared to pre-industrial levels. It is believed that an electrification of the transport sector will reduce its negative environmental impact. To reach the goals set by the Paris Agreement we are in need of quick development towards an electrified fleet of vehicles. Despite this urgency electric vehicles (EVs) have failed to reach the majority of the market, instead it has stuck in the chasm between the early adopters and the early majority of the markets. This is due to three main challenges; EVs are relatively expensive compared to conventional petrol- and diesel-powered vehicles, EVs have an inadequate driving range, and the access to a functional charging infrastructure is limited. This thesis focuses on the third challenge regarding charging infrastructure. The charging infrastructure is dependent on the existing electricity distribution infrastructure, i.e. the grid. It is rather time-consuming and costly to strengthen the grid, which is deemed necessary for enabling a roll-out of a charging infrastructure that meets the needs of current and near-future EV operators. This research provides an alternative way of approaching the issues. Instead of strengthening the grid by digging up old cables it looks into the opportunities of incorporating stationary battery storages as a buffer between the EV charging stations and the grid connection point. This battery solution can reduce the power outtake and smoothen out the load from EV charging, thus limiting the impact of EV charging from a grid perspective. The research assesses what type of pathways this solution could follow to successfully drive the adoption of EVs. Furthermore, the study tries to understand how these solutions could be designed to deliver the necessary values regarding EV charging and reducing the overall power outtake from grid connection points. The thesis is carried out by analyzing collected quantitative and qualitative data through the lens of three main theories. These are transition theory, theory on eco-innovations, and theory on the diffusion of innovations. The thesis finds that the two pathways for a battery supported charging infrastructure that will be most efficient in speeding up the adoption rate of EVs is within a workplace and public charging setting in city and urban environments. For both pathways it is expected that a centralized concept, with one battery solution connected to several charging points, will be most feasible in the short-term, which is important as the need for developments are very urgent. The workplace charging will provide 3,6 kW AC-charging while the public charging provides 150 kW DC-charging. The solution is expected to be cost-efficient for specific locations, especially for public charging in city environments with strained grid infrastructures. The study provides an initial assessment for the city of Stockholm which indicates that the power outtake can be reduced by 63,5–112,2 MW in 2030. This means that the current grid infrastructure could support a larger number of EVs, thus reducing the greenhouse-gas emissions from the transport sector and bringing us closer to reaching the goals set by the Paris Agreement. Parisavtalet utformades år 2015 för att reducera vår klimatpåverkan och begränsa temperaturökningen till 2°C jämfört med nivåerna som rådde innan den industriella revolutionen. Förhoppningen är att en elektrifiering av transportsektorn kan reducera dess negativa klimatpåverkan. För att nå målen i Parisavtalet behövs en snabb omställning mot en elektrifiering av fordonsflottan. Trots situationens brådskande karaktär har elbilar fastnat i en klyfta mellan den begränsade tidiga marknaden och den sena marknaden, vilken utgör majoriteten av kunderna. Det finns tre primära anledningar till detta; elbilar är dyra jämfört med bensin- och dieseldrivna bilar, räckvidden för elbilar är otillräcklig, och det råder begränsad tillgång till en funktionell laddinfrastruktur. Den här studien fokuserar på den tredje anledningen kring otillräcklig laddinfrastruktur. Laddinfrastrukturen är beroende av det existerande elnätet och dess distributionskapacitet. En förstärkning av elnätet är i många fall nödvändig för att möjliggöra en utrullning av en laddinfrastruktur som möter dagens och morgondagens behov. Istället för att förstärka elnätet genom att gräva ner tjockare kablar så fokuserar denna studie på en alternativ lösning kring laddinfrastruktur sammankopplat med stationära batterilager. Batterilagret agerar som en buffert mellan anslutningspunkten till elnätet och laddningspunkten för elbilar. Genom att reducera effektuttaget och jämna ut lastkurvan för elbilsladdning kan en batterilösning begränsa den negativa påverkan det förväntas ha på elnätet. Studien undersöker vilka vägar denna batterilösning kan ta för att öka antalet elbilar i fordonsflottan. Efter att ha förstått vilka dessa lösningsvägar är så analyserar studien hur dessa lösningar kan vara uppbyggda för att erbjuda de efterfrågade och nödvändiga värdena för elbilsladdning och elnätets fortsatta funktionalitet. Studien bygger på analys av kvalitativa och kvantitativa data. Analysen utförs genom att applicera koncept hämtade från teorier kring teknologiska övergångar, miljöinnovationer och spridning av innovationer. De två lösningsområden som förväntas vara mest effektiva i att driva en ökning av antalet elbilar i Sverige är arbetsplatsladdning samt offentlig laddning i stadsmiljöer. En lösning med ett centraliserat batterisystem där en batterilösning är kopplat till flera laddstationer antas vara mest genomförbar på kort sikt, vilket anses vara centralt på grund av utmaningarnas brådskande karaktär. För arbetsplatsladdning tillhandahålls 3,6 kW AC-laddning och för offentlig laddning tillhandahålls 150 kW DC-laddning. Lösningarna förväntas vara kostnadseffektiva for specifika platser och användarprofiler, speciellt för offentlig laddning i stadsområden med ansträngda elnät. En initial uppskattning visar att en laddinfrastruktur kopplat till stationära batterilager inom de två lösningsområdena kan minska Stockholms effektuttag för elbilsladdning med 63,5–112,2 MW år 2030. Detta betyder att dagens elnät kan tillgodose ett ökat antal elbilar, vilka genererar färre utsläpp av växthusgaser och ger oss en bättre chans att nå Parisavtalets mål.

Electric vehicle penetration, comparison between Norway, Japan and Spain.

Scipedia content — Tue, 26 Jan 2021 18:03:33 +0100

The aim of the study is to analyze how the country with the highest percentage of electric vehicles as is Norway has managed to become it and analyze the case of Japan and Spain with the charact of each country. The batteries are evolving and increasing their performance, but it is necessary a safe network of charging stations for electric vehicles to reduce the "range anxiety". A discuss of the electric car penetration with different Policies and Legislacy to incentivize the electric vehicle will be made to see the Spanish situation respect to Norway and Japan.

Productivity in Estonian road freight transportation

Scipedia content — Tue, 26 Jan 2021 18:03:01 +0100

Roteamento de tráfego veicular colaborativo e sem infraestrutura para sistemas de transportes inteligentes

Scipedia content — Tue, 26 Jan 2021 18:02:28 +0100

Orientadores: Leandro Aparecido Villas, Edmundo Roberto Mauro Madeira Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação Made available in DSpace on 2020-02-07T18:33:19Z (GMT). No. of bitstreams: 1 Akabane_AdemarTakeo_D.pdf: 8120275 bytes, checksum: cd6482ee4f51bb13e31c71d5350d9fc7 (MD5) Previous issue date: 2019 Resumo: Devido à atual tendência mundial de urbanização, a sociedade moderna enfrenta, cada vez mais, sérios problemas de mobilidade urbana. Além disso, com o aumento constante do fluxo de tráfego veicular, as atuais soluções existentes para gerenciamento de tráfego se tornaram ineficientes. Com isso, para atender às crescentes necessidades dos sistemas de transporte, é necessário sistemas de transporte inteligentes (ITS). O desenvolvimento de ITS sustentável requer integração e interoperabilidade contínuas com tecnologias emergentes, tais como as redes veiculares (VANETs). As VANETs são consideradas uma tecnologia promissora que provê aplicações críticas de segurança e serviços de entretenimento, consequentemente melhorando a experiência de viagem do motorista e dos passageiros. Esta tese propõe um sistema de gerenciamento de tráfego de veículos sem a necessidade de uma infraestrutura de apoio. Para alcançar o sistema desejado foram necessários propor soluções intermediárias que contribuíram nesta tese. A primeira contribuição reside em uma solução que emprega conhecimento histórico dos padrões de mobilidade dos motoristas para obter uma visão global da situação da rede viária. Diferentemente de outras abordagens que precisam de troca constante de informações entre os veículos e o servidor central, nossa solução utiliza informações espaciais e temporais sobre padrões de mobilidade, além das informações específicas da infraestrutura viária, a fim de identificar congestionamentos no tráfego, permitindo, assim, o planejamento de roteamento de veículos. Como segunda contribuição, foi proposta uma solução distribuída para calcular a intermediação egocêntrica nas VANETs. Por meio da métrica egocêntrica foi proposto um mecanismo inovador de ranqueamento de veículos em redes altamente dinâmicas. As principais vantagens desse mecanismo para aplicações de VANETs são: (i) a redução do consumo de largura de banda e (ii) a superação do problema de topologias altamente dinâmicas. A terceira contribuição é uma solução de planejamento de rotas colaborativo com intuito de melhorar o gerenciamento do tráfego de veículos em cenários urbanos. Como última contribuição, esta tese integra as soluções descritas acima, propondo um sistema eficiente de gerenciamento de tráfego de veículos. As soluções propostas foram amplamente comparadas com outras soluções da literatura em diferentes métricas de avaliação de desempenho. Os resultados mostram que o sistema de gerenciamento de tráfego de veículos proposto é eficiente e escalável, qual pode ser uma boa alternativa para mitigar os problemas de mobilidade urbana Abstract: Due to the current global trend of urbanization, modern society is facing severe urban mobility problems. In addition, considering the constant increase in vehicular traffic on roads, existing traffic management solutions have become inefficient. In order to assist the increasing needs of transport systems today, there is a need for intelligent transportation systems (ITS). Developing a sustainable ITS requires seamless integration and interoperability with emerging technologies such as vehicular ad-hoc networks (VANETs). VANETs are considered to be a promising technology providing access to critical life-safety applications and infotainment services, consequently improving drivers¿ and passengers¿ on-road experiences. This thesis proposes an infrastructure-less vehicular traffic management system. To achieve such a system, intermediate solutions that contributed to this thesis were proposed. The first contribution lies in a solution that employs historical knowledge of driver mobility patterns to gain an overall view of the road network situation. Unlike other approaches that need constant information exchange between vehicles and the central server, our solution uses space and temporal information about mobility patterns, as well as road infrastructure information, in order to identify traffic congestion, thus allowing for vehicle routing planning. Secondly, a distributed solution to calculate egocentric betweenness in VANETs was proposed. Through the egocentric metric, an innovative vehicle ranking mechanism in highly dynamic networks was proposed. The main advantages of this mechanism for VANETs applications are (i) reduced bandwidth consumption and (ii) overcoming the problem of highly dynamic topologies. The third contribution is a collaborative route planning solution designed to improve vehicle traffic management in urban settings. As the last contribution, this thesis integrates the solutions described above, proposing an efficient vehicle traffic management system. The proposed solutions were widely compared with other literature solutions on different performance evaluation metrics. The evaluation results show that the proposed vehicle traffic management system is efficient, scalable, and cost-effective, which may be a good alternative to mitigate urban mobility problems Doutorado Ciência da Computação Doutor em Ciência da Computação 2015/25588-6 FAPESP

Urban mobility solutions : the potential of free-floating carsharing in nine selected European countries

Scipedia content — Tue, 26 Jan 2021 17:56:27 +0100

Carsharing, a modern mobility solution, can change the way how we move around cities. However, the concept has not everywhere lived up to its predicted market potential yet. In Europe, it is noticeable that the system is mostly dominating in the Western part. Countries in Eastern and Southern Europe on the other hand are characterized by younger and smaller carsharing markets. With the help of expert interviews, the current situation of carsharing in nine selected European countries, that are classified as emerging markets by MSCI, was investigated. The results affirm, that in most of those countries a minor number of carsharing operators with small fleets are present. Yet, some others have already advanced further. The study also revealed several critical success factors for free-floating carsharing, again with input from an expert. Finally, based on those critical success factors, the nine countries were individually assessed and ranked according to their current market potential using the Simple Multi-Attribute Rating Technique. It turned out that especially Poland offers beneficial conditions for free-floating carsharing. O carsharing, uma moderna solução de mobilidade, pode mudar a forma como nos movimentamos pelas cidades. No entanto, não é possível afirmar que todo o seu potencial de mercado tenha sido atingido na plenitude. Na Europa, a solução tem sido predominantemente implementada na parte Ocidental. Contrariamente, os países da Europa Oriental e do Norte, apresentam, neste âmbito, mercados em estádios ainda iniciais. Através do contributo prestado pela realização de entrevistas com especialistas, foi possível aferir a situação atual do carsharing em países selecionados. Como elemento comum surge o fato destes serem classificados como mercados emergentes pelo MSCI. Os resultados concluem, na maioria desses países, a existência de um número reduzido de operadores de carsharing, apresentado igualmente um número reduzido de veículos disponíveis associados às operações. Todavia, dos países estudados alguns evidenciaram particular destaque. Igualmente, no presente estudo, e com o respaldo de opiniões especializadas, são apresentados vários fatores críticos de sucesso para o free-floating carsharing. Finalmente, é com base nestes que os nove países foram avaliados individualmente e classificados de acordo com seu potencial de mercado atual usando a Técnica de Classificação Simples de Multiatributos. Observou-se que a Polônia apresenta condições propícias à implementação do free-floating carsharing.

Users and the upscaling of innovation in sustainability transitions : The cases of car-sharing and electric vehicles

Scipedia content — Tue, 26 Jan 2021 17:56:04 +0100

The use of sustainable innovations, such as car-sharing and electric vehicles, has grown considerably in the past years. Most commentators ascribe this growth to the efforts of companies such as Tesla and SnappCar or government intervention. However, the role of end-users in sustainability transitions has received considerably less attention. This thesis focuses on the users of car-sharing and the electric car. The aim of the thesis is to obtain more insight in the characteristics of users as well as in their active role in the upscaling of innovations in sustainability transitions. These innovations are systemic: they entail changes in technologies, use patterns, markets, infrastructures and institutions. A questionnaire was used to gain insights in motivations for car-sharing. Car sharing is mostly driven by environmental and financial motivations, while other forms of sharing are driven by different sets of motivations. From a user perspective, one can thus not speak of one sharing economy. Differences in motivations for sharing economy participation equally exist between socio-demographic groups. For example, people on lower incomes have higher financial motivations, older people have more social motivations and women are more environmentally driven. Subsequently, the diffusion of two forms of car-sharing in the Netherlands was mapped. These concerned business-to-consumer car-sharing, in which a company owns cars that are located in neighbourhoods, and peer-to-peer car-sharing, in which users rent out their own cars via an online platform. A spatially heterogenous conception of the Multi-Level Perspective on transitions was developed, emphasizing geographical differences in regime, niche and landscape levels. The diffusion of car-sharing was linked to socio-demographic and built environment characteristics of neighbourhoods. Business-to-consumer car-sharing is limited to urban areas, with specific groups of users. Peer-to-peer car-sharing appears in all kinds of neighbourhoods. One explanation is its complementarity to the existing regime: underutilized capacity of cars that are already there is put to use. The active role of users in diffusion is studied by means of an analysis of an internet forum of mainly Tesla users. Their contribution to different dimensions of upscaling in sustainability transitions is assessed: the built-up of an innovation system, the geographical diffusion of the electric vehicle, and the removal of institutional barriers to growth. The users deliver a unique contribution to these dimensions. They share knowledge and practical solutions for the daily use of electric vehicles. They lobby for chargers, and mingled in international discussions about standardization. In spite of these contributions, the forum is relatively chaotic and subjective. Still, users are shown to be important actors in upscaling transitions. Finally, the role of users in the growth of electric vehicles is considered from an assemblage perspective. This approach goes back to the philosophies of Deleuze and Delanda and describes a world of interconnected assemblages that are instable. It challenges current conceptualizations of the socio-technical regime as stable and homogenous. The Tesla internet forum is a combination of very different users: environmentalists, car hobbyists and gadget freaks. Exactly the temporary alliances between those different groups contribute to the further diffusion of the electric vehicle.

Selection support of mass transportation connecting urban centers to airports

Scipedia content — Tue, 26 Jan 2021 17:55:01 +0100

Orientador: Maria Lucia Galves Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo Made available in DSpace on 2019-11-08T14:18:39Z (GMT). No. of bitstreams: 1 Gaiofatto_AnaCarolinaCoutoDonaires_M.pdf: 2839033 bytes, checksum: 06e08cfd53aaf29e6761cde75fb9a815 (MD5) Previous issue date: 2019 Resumo: O aeroporto é um importante polo gerador de tráfego terrestre. Diante do grande fluxo de pessoas que se deslocam do centro da cidade em direção ao aeroporto, é importante que esta ligação seja planejada e implementada de maneira eficaz, com um transporte coletivo de qualidade, que promova a integração dos modos e incentive o uso pelos passageiros. O objetivo deste trabalho é auxiliar na escolha de alternativas de transporte público entre a área central da cidade e o aeroporto. Para tanto, foi utilizado o método de Auxílio Multicritério à Decisão (AMCD), uma metodologia simples que utiliza um processo integrado de tomada de decisão de múltiplos critérios. A proposta foi aplicada para ajudar no desenvolvimento de opções e selecionar um sistema de transporte público apropriado para a ligação entre o centro da cidade de Campinas e o Aeroporto Internacional de Viracopos Abstract: Airports are major land traffic generators. In the face of the great flow of people traveling from the city centers towards the airport, it is important that this connection is planned and effectively implemented with a high-quality mass transportation, which allows interconnection to different transportation modes and encourages its use. The objective of this research is to assist in the selection of public transportation alternatives between the central area of the city and the airport. To achieve this purpose, the Multi-Criteria Decision Aid (MCDA) method was applied, as it is a simple methodology comprised of an integrated multi-criteria decision-making process. The method was applied to support the development of the selection of an appropriate public transportation system for the connection between the downtown area of Campinas and the Viracopos International Airport Mestrado Transportes Mestra em Engenharia Civil 01-P-03713/2017 CAPES

A systematic approach to the analysis and design of electrical machines for automotive traction applications

Scipedia content — Tue, 26 Jan 2021 17:53:43 +0100

Negli ultimi decenni, il processo di elettrificazione ha interessato diversi aspetti e attività delle moderne società industrializzate. In questo contesto, l'elettrificazione dei trasporti mostra ancora un ritardo significativo. Ciò è dovuto principalmente alle prestazioni altamente competitive del petrolio come fonte di energia sia sotto il profilo tecnico sia economico. Tuttavia, le considerazioni in merito all'inquinamento dell'aria unitamente a politiche di autosufficienza energetica hanno recentemente aumentato l'interesse dell'industria automobilistica verso i powertrain ibridi ed elettrici. Inoltre, in pochi anni, i powertrain elettrici hanno raggiunto le prestazioni di quelli a combustione interna e, grazie a particolari caratteristiche (quali ad esempio il sovraccarico e gli alti livelli di efficienza), hanno persino superato i risultati dei powertrains convenzionali. Il presente lavoro di tesi si concentra sulle macchine elettriche usate per la propulsione e il freno dei nuovi autoveicoli, con una particolare attenzione alla geometria di rotore, alle configurazioni degli avvolgmenti e ai più importanti trade-off relativi al design della macchina elettrica. Anche le possibilità di controllo sull'intero intervallo di velocità sono state considerate accuratamente. In più, un nuovo modello magnetico ricorsivo è stato sviluppato per eseguire ottimizzazioni multi-obiettivo dei parametri di rotore e un'inedita geometria di tipo spoke-type viene proposta per ridurre il volume del magnete permanente nella macchina. Questa tesi è organizzata nel seguente modo: l'introduzione fornisce le informazioni di contesto generale in materia di elettrificazione dell'automobile, il capitolo 1 si occupa dei requisiti specifici di un motore per trazione dimostrando che i motori a magneti permanenti interni sono quelli che meglio soddisfano tali vincoli, nel capitolo 2 un'approfondita analisi di due macchine prese in considerazione come casi di studio viene svolta per mezzo sia di un'approccio analitico sia di simulazioni a elementi finiti, quindi nel capitolo 3 si esegue un'analisi critica delle principali opzioni di progetto della macchina e infine, nel capitolo 4, le linee-guida risultanti vengono applicate al design di un nuovo motore prototipo destinato alle corse di formula studentesca (SAE). Il progetto copre non soltanto i tipici aspetti elettromagnetici del motore ma anche le proprietà termiche e meccaniche della macchina. In the last decades, the electrification process has involved several aspects and activities of modern industrialized societies. In this context, the electrification of the transportation sector still exhibits a significant delay. This is mainly due to the rather competitive oil performances as an energy source from both a technical and economic point of view. However, air pollution considerations as well as energy self-sufficiency policies have recently raised the industrial interest for automotive hybrid and electric powertrains. Moreover, in just a few years, the electrical powertrains have reached the Internal Combustion Engine performances and, thanks to their particular features (such as the overload and the very high efficiency levels), they even outperformed most of the conventional powertrains. This work focuses on the electrical machines used for the new car propulsion and braking, with special regard to the rotor geometry, winding configurations and all the most important trade-offs related to the machine design. The control capabilities over the whole speed range have also been considered carefully. In addition, a new recursive magnetic model has been developed to perform multi-objective rotor parameters optimization and a novel spoke-type geometry is proposed to reduce the machine permanent magnet volume. This thesis is organized in the following way: the introduction gives the general background information about the car electrification topic, the chapter 1 deals with the specific requirements for a traction motor showing that the Interior Permanent Magnet is the motor type which best meets those constraints, in the chapter 2 a deep analysis is carried out on two case study machines by means of both analytic approach and Finite Elements simulations, then chapter 3 performs a critical analysis of the machine main design options and finally, in chapter 4, the resultant guidelines are applied to the design of a new motor prototype for Student Formula races. The design covers not only the typical electric and magnetic aspects of the motor but also the thermal and mechanical properties of the machine.

Cost and behavioral drivers of the market penetration of battery electric vehicles

Scipedia content — Tue, 26 Jan 2021 17:47:56 +0100

The government’s aim of one million environmentally friendly electric vehicles (EVs) on German roads by 2020 has been withdrawn due to the low demand for such vehicles. The rea- sons are different and range from unfavorable price-performance ratios to the actual battery of EVs itself. Against this background, successful industrial and policy measures are necessary in order to offer customer-oriented solutions for EVs in Germany. This dissertation contributes to the evaluation of battery electric vehicles (BEVs) from a consumer-oriented total cost of ownership (TCOC) and a behavioral decision making (vehicle choice) perspective, using three re- search approaches to derive potential industrial and policy measures for Germany. These three approaches are described below in detail and are interconnected as follows: (1) modeling of the TCOC followed by (2) analyzing of the TCOC information disclosure under a risk situation and (3) optimizing of the TCOC using an optimal cost package for BEVs. The first research paper to be published formed the basis for this cumulative dissertation. In the paper, a TCOC model was developed to identify the profitability, including potential cost risks, of selected passenger vehicles. This approach was achieved by extending existing TCOC models with often ignored ownership costs, such as the resale value for the battery second use and second life. We identified the profitability for the ten most frequently registered BEVs in Germany in 2014 and compared them with similar internal combustion engine vehicles (ICEVs) fueled with gasoline (ICEV-SI) or diesel (ICEV-CI). Here, we also considered full hybrid electric vehicles (HEVs), as they play an important role in the transformation phase between BEVs and ICEVs. We analyzed the results under various assumptions, including a Monte Carlo simulation with 500,000 draws per simulation for 2016 and 2021. Results show that four BEVs – BMWi3, TeslaS, Mercedes B250e, and TeslaX – and five HEVs – Honda Jazz, Toyota Auris, LexusIS, Mercedes E300h, and Mercedes S400h – are profitable despite cost risks in the elec- tricity/fuel and battery price compared to their equivalent ICEVs in 2016. The purchase-based incentive in the form of a subsidy shows a positive effect on the actual TCOC but not for all selected BEVs. The second research paper analyzed two potential use-based incentive measures in the form of TCOC information disclosure and a driving ban on ICEVs with regard to the purchasing decision for a BEV in order to determine the effectiveness of both influential factors. This approach was achieved by asking 379 potential consumers via an online experiment, including a post-experimental questionnaire throughout Germany. We analyzed the choice decision for a BEV by using a logistic regression with a linear generalized estimating equation (GEE) method. Results show that these two potential use-based incentives can have a positive impact on the choice decision for BEVs, as the threat of a driving ban on ICEVs and the TCOC information weighted with the TCOC value difference have a significant positive effect on the decision of whether to buy a BEV (p

Adopting Transit-Oriented Development (TOD)in Metro-Manila Railway system : Considering Sweden’s Experience and Learning

Scipedia content — Tue, 26 Jan 2021 17:45:46 +0100

Transit-oriented development (TOD) or as it is referred to in Sweden ABC (Arbete, Bostad,och Centrum which means work, housing, and city center) is the highly prevailing and excitingconcept of integrating urban communities, activities, people, buildings and public places together.This idea is primarily focused upon the creation of walkable, pedestrian-oriented communities andcycling connections, which are centered among the high-quality train systems.This research has been conducted to provide a comprehensive analysis related to theimplementation of the TOD model within Metro-Manila, by enhancing its railway network toreduce the problem of high traffic congestion and to provide a better service to a larger number ofpassengers. To carry out this research, various ideas were taken from the TOD projects that havebeen implemented within the metro system of Stockholm as an example to be used for Metro-Manila.In order to conduct this study, both quantitative and qualitative research approaches wereutilized to conduct an in-depth analysis of the current conditions of the railway transportationsystem in Metro-Manila. Within the qualitative part of this research, a SWOT analysis and adetailed comparison was also carried out to determine the efficiency of Metro-Manila and the areaswhere it needed significant improvements. Whereas, for the quantitative analysis, a survey wasconducted from both the people of Metro-Manila and Stockholm (i.e., 226 respondents) tounderstand the current situations of these railway networks more appropriately. The survey wasdesigned based on close-ended five (5) points Likert Scale questions. The results of the surveysrevealed that the respondents were mostly satisfied with the metro system in Stockholm andimplementation of the TOD concepts but usually dissatisfied with Metro-Manila railway system.An interview was also conducted with the officials of the Stockholm transport organization (SL)to gather more insight related to the problems within the railway networks.It was revealed from the analysis that Metro-Manila railway network has been facingsevere problems in terms of limited capacity, poor facilities, unavailability of trains, andmismanagement. The analysis also revealed a few problems within the Stockholm metro systemas well. However, to eradicate or mitigate these problems, several strategies and recommendationshave been proposed within this research. Based from the facts the researcher has gathered and ispresented in this research paper, it was evident that implementation of transit-orienteddevelopment, even if its limited to just the basic concepts, will highly be beneficial in botheconomic and societal aspects and its effectively and efficiently is enough to satisfy the needs ofthe daily commuters and would result in a dramatical reduction of traffic congestions.

Revealing and Characterizing MPLS Networks

Scipedia content — Tue, 26 Jan 2021 17:42:53 +0100

The Internet is a wide network of computers in constant evolution. Each year, more and more organizations are connected to this worldwide network. Each of them has its own structure and administration that are not publicly revealed for economical, political, and security reasons. Consequently, our perception of the Internet structure, and more specifically, its topology, is incomplete. In order to balance this lack of knowledge, the research community relies on network measurements. Most of the time, they are performed based on the well-known tool traceroute. However, in practice, an operator may privilege other technologies than IP to forward packets inside its network. MultiProtocol Label Switching (MPLS) is one them. Even if it is heavily deployed by operators, it has not been really investigated by researchers. Prior to this thesis, only two studies focused on the identification of MPLS tunnels in traceroute data. Moreover, while one of them does not take all possible scenarios into account, the other lack of precision in some of its models. In addition, MPLS tunnels may hide their content to traceroute. Topologies inferred from such data may thus contain false links or nodes with an artificially high degree, leading so to biases in standard graph metrics used to model the network. Even if some researchers already tried to tackle this issue, the revelation of hidden MPLS devices in traceroute data is still an open question. This thesis aims at characterizing MPLS in two different ways. On the one hand, at an architectural level, we will analyze in detail its deployment and use in both IPv4 and IPv6 networks in order to improve its state-of-the-art view. We will show that, in practice, more than one IPv4 trace out of two crosses at least one MPLS tunnel. We will also see that, even if this protocol can simplify the internal architecture of transit networks, it also allows some operators to perform traffic engineering in their domain. On the other hand, MPLS will be studied from a measurement point of view. We will see that routers from different manufacturers may have distinct default behaviors regarding to MPLS, and that these specific behaviors can be exploited to identify MPLS tunnels during traceroute measurements. More precisely, we will focus on new methods able to infer the presence of tunnels that are invisible in traceroute outputs, as well as on mechanisms to reveal their content. We will also show that they can be used in order to improve the inference of Internet graph properties, such as path lengths and node degrees. Finally, these techniques will be integrated into Trace the Naughty Tunnels (TNT), a traceroute extension able to identify all types of MPLS tunnels along a path towards a destination. We will prove that this tool can be used in order to get a detailed quantification of MPLS tunnels in the worldwide network. TNT is publicly available, and can therefore be part of many future studies conducted by the research community. Internet est un immense réseau informatique en constante évolution. Chaque année, de plus en plus d’organisations s’y connectent. Chacune d’elles est gérée et administrée indépendamment des autres. En pratique, l’architecture interne de leur réseau n’est pas rendue publique pour des raisons politiques, économiques, ou de sécurité. Par conséquent, notre perception de la structure d’Internet, et plus particulièrement de sa topologie, est incomplète. Afin de pallier ce manque de connaissance, la communauté de la recherche s’appuie sur des mesures de réseau. La plupart du temps, elles sont réalisées avec l’outil traceroute. Cependant, des technologies autres que IP peuvent être privilégiées pour transférer les paquets dans un réseau. MultiProtocol Label Switching (MPLS) est l’une d’entre elles. Même si cette technologie est largement déployée dans Internet, elle n’est pas bien étudiée par les chercheurs. Avant cette thèse, seulement deux travaux se sont intéressés à l’identification d’MPLS dans les données collectées avec traceroute. Alors que le premier ne prend pas en compte tous les scénarios possibles, le second propose des modèles qui manquent de précision. De plus, les tunnels MPLS peuvent dissimuler leur contenu à traceroute. Les topologies inférées sur base de ces données peuvent donc contenir de faux liens, ou des noeuds avec un degré anormalement élevé. Les différentes modélisations d’Internet qui en résultent peuvent alors être biaisées. Aujourd’hui, la question de la révélation des routeurs MPLS qui sont invisibles dans les données de mesure n’est toujours pas résolue, même si certains chercheurs ont déjà proposé quelques méthodes pour y parvenir. Cette thèse a pour but de caractériser MPLS de deux manières différentes. Dans un premier temps, au niveau architectural, nous analyserons en détail son déploiement et son utilisation dans les réseaux IPv4 et IPv6 afin d’améliorer l’état de l’art. Nous montrerons qu’en pratique, plus d’une trace IPv4 sur deux traverse au moins un tunnel MPLS. Nous découvrirons également que bien que ce protocole peut être utilisé pour simplifier l’architecture interne des réseaux de transit, il peut aussi être déployé pour la mise en place de solutions d’ingénierie de trafic. Dans un second temps, MPLS sera étudié d’un point de vue mesure. Nous verrons que les comportements par défaut liés au protocole varient d’un fabricant de routeur à l’autre, et qu’ils peuvent être exploités afin d’identifier les tunnels MPLS dans les données traceroute. Plus précisément, nous découvrirons de nouvelles méthodes capables d’inférer la présence de tunnels invisibles avec traceroute, ainsi que de nouvelles techniques pour révéler leur contenu. Nous montrerons également qu’elles peuvent être utilisées afin d’améliorer la modélisation d’Internet. Pour terminer, ces techniques seront intégrées à Trace the Naughty Tunnels (TNT), une extension de traceroute qui permet d’identifier tous les types de tunnels MPLS le long du chemin vers une destination. Nous prouverons que cet outil peut être utilisé pour obtenir des statistiques détaillées sur le déploiement d’MPLS sur Internet. TNT est disponible publiquement, et peut donc être librement exploité par la communauté de la recherche pour de multiples futures études.

Potential for reducing atmospheric emissions from the implementation of the BRT : a case study in Belém - PA

Scipedia content — Tue, 26 Jan 2021 17:40:43 +0100

Orientador: Sônia Regina da Cal Seixas Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica Made available in DSpace on 2019-07-22T14:23:28Z (GMT). No. of bitstreams: 1 HoshinoNeta_CarolinaShizue_M.pdf: 1735861 bytes, checksum: 0a5ccf53088192b63d7df4d941d4fb5d (MD5) Previous issue date: 2019 Resumo: A mobilidade urbana bem planejada, com sistemas integrados e sustentáveis, é um elemento facilitador ao desenvolvimento e fundamental à qualidade de vida nas cidades. O uso do BRT como alternativa de transporte público tem se expandido em vários países em função do seu custo-benefício atrativo para o Desenvolvimento Orientado ao Transporte Sustentável (DOTS). Ao longo deste trabalho, buscou-se analisar os impactos da implementação do Projeto BRT Belém nas emissões atmosféricas a partir da metodologia Emissions Evaluation Models for Projects (TEEMP). Para isso, foram avaliados critérios do Padrão de Qualidade BRT, incluindo aspectos das categorias BRT Básico, Planejamento dos Serviços, Infraestrutura, Estações, Comunicações, Acesso e Integração e Deduções de Operações. Também foram inseridos dados específicos do projeto na planilha de cálculo do modelo, para que os cenários de reduções de emissões fossem simulados, um com a implementação do BRT Belém e outro sem, considerando um horizonte de 20 anos. Os resultados demonstraram que o sistema terá potencial de evitar a emissão de 196.992,2 t de CO2e, 4,8 t de MP e 631,7 t de NOx. Além disso, contabilizaria uma economia de 79 milhões de litros de combustível em uma redução de 230,5 milhões de quilômetros percorridos. Embora os modelos de cenários tenham indicado resultados positivos a respeito da redução de emissões atmosféricas e co-benefícios, ao compararmos ao potencial de desempenho de outros BRTs do Brasil e do mundo, é possível perceber que o desempenho está aquém do potencial que esse tipo de equipamento poderia ter, havendo pontos de melhoria a serem atentados Abstract: Well-planned urban mobility, with integrated and sustainable systems, is a facilitating element for development and fundamental to the quality of life in cities. The use of BRT as an alternative public transport has expanded in several countries due to its attractive cost-benefit for Transit Oriented Development (TOD). Throughout this work, we sought to analyze the impacts of the implementation of the project BRT Belém in atmospheric emissions from the methodology Emissions Evaluation Models for Projects (TEEMP). For this, we evaluated the criteria of the BRT quality standard, including criteria of the basic BRT categories, services planning, infrastructure, stations, communications, access and integration and deductions of operations. Specific project data were also inserted in the Model calculation spreadsheet so that the scenarios of emission reductions were simulated, one with the implementation of the BRT Belém and the other without, considering a horizon of 20 years. The results show that the system will have the potential to avoid the emission of 196,992.2 ton of CO2e, 4.8 ton of MP and 631.7 ton of NOx. In addition, it would count a savings of 79 million liters of fuel in a reduction of 230.5 million kilometers traveled. Although the scenario models have indicated positive results regarding the reduction of atmospheric and co emissions, when comparing the performance potential of other BRTs in Brazil and the world, it is possible to realize that performance is short of Potential that this type of equipment could have, with improvement points being attempted by the operational administration of the system Mestrado Planejamento de Sistemas Energeticos Mestra em Planejamento de Sistemas Energéticos CAPES

Design of a yaw rate control for a Formula Student electric car

Scipedia content — Tue, 26 Jan 2021 17:36:53 +0100

This project deals with the study and design of a direct yaw rate control for a two rear independent wheel drive Formula Student electric vehicle. It takes as a base of design the 2016-17 season car fully built and developed car by the students of e-Tech Racing Formula Student team of the EEBE First chapters are composed by an introduction of Formula Student concept and its environment, the main technical characteristics of the car and the mathematic base about vehicle dynamics The core of the project resides in the chapters 4 and 5, where it is presented the algorithm and the controller. In chapter 4 is detailed an explanation of all different parts and is showed the system stability within the proposed PI controller. In Chapter 5, simulations of different scenarios have been done using inputs as step function, ramp o more realistic trajectory as Skip Pad. Finally, results obtained with the controller simulations are commented critically highlighting points of strength and weakness of the solution.

Pavement monitoring utilizing smartphones, vibration sensors and pattern recognition for the detection and classification of roadway pavement anomalies

Scipedia content — Tue, 26 Jan 2021 17:36:09 +0100

Includes bibliographical references (p. 274-290) and index. Number of sources in the bibliography: 134 Thesis (Ph. D.) -- University of Cyprus, Faculty of Engineering, Department of Civil and Environmental Engineering, 2018. The University of Cyprus Library holds the printed form of the thesis. Η συστηματική διαχείριση των οδοστρωμάτων αποκτά ολοένα και μεγαλύτερη σημασία, καθώς η επιφάνειά τους εξακολουθεί να αλλοιώνεται με την πάροδο του χρόνου και ταυτόχρονα τα επίπεδα του προϋπολογισμού να μειώνονται, εξαιτίας της ελαχιστοποίησης των κεφαλαίων χρηματοδότησης και του αυξημένου ανταγωνισμού για κεφάλαια. Η προτεινόμενη έρευνα εξετάζει την ανάπτυξη ενός συστήματος παρακολούθησης οδοστρωμάτων, που με συνδυασμό με σύστημα γεωγραφικών πληροφοριών (GIS), δίνει τη δυνατότητα στους υπεύθυνους διαχείρισης του οδοστρώματος να εξετάζουν τα οδοστρώματά τους την κατάλληλη χρονική στιγμή έτσι ώστε να βελτιώνουν την λειτουργία και διαχείριση τους, και να αποφεύγουν την ανώφελη κατασκευή νέων οδοστρωμάτων. Τα δεδομένα της κατάστασης της επιφάνειας του οδοστρώματος μπορούν να συλλεχθούν και να αναλυθούν σε τακτική βάση από οχήματα γενικής χρήσης και τα έξυπνα κινητά τηλεφωνίας. Η προτεινόμενη μεθοδολογία θα επιτύχει σημαντική εξοικονόμηση στις δαπάνες που αφορούν τη συντήρηση και την αποκατάσταση του οδοστρώματος και τις σχετικές επιπτώσεις από το κλείσιμο των δρόμων. Επίσης, θα εξοικονομήσει κόστη που σχετίζονται με την αγορά και χρήση εμπορικά διαθέσιμων Συστημάτων Διαχείρισης Οδοστρωμάτων.Η μελέτη διερευνά τη χρήση δεδομένων, που συλλέγονται από αισθητήρες έξυπνων κινητών τηλεφώνων και από συσκευές διαγνωστικού ελέγχου των αυτοκινήτων (OBD-II) καθώς τα οχήματα βρίσκονται σε κίνηση, για την ανίχνευση και την ταξινόμηση των ανωμαλιών της επιφάνειας του οδοστρώματος. Η συλλογή δεδομένων που βασίζεται σε έξυπνα κινητά τηλέφωνα συνοδεύεται από στατιστική ανάλυση, τεχνικές τεχνητών νευρωνικών δικτύων, διάφορους αλγόριθμους και μοντέλα ταξινόμησης δέντρων για τον διαχωρισμό των ανωμαλιών ανίχνευσης του οδοστρώματος. Η προτεινόμενη μέθοδος και αρχιτεκτονική του συστήματος έχουν ήδη αναπτυχθεί (και ήδη δοκιμαστεί σε υφιστάμενο οδικό δίκτυο) χρησιμοποιώντας τέσσερις παραμέτρους στην ανάλυση, έχουν ελεγχθεί σε σχέση με πέντε τύπους ανωμαλιών του οδοστρώματος, και κατ’ επέκταση έχουν επικυρωθεί έναντι εκατοντάδων διαδρομών οδοστρώματος (που αφορούν πάνω από 45000 σημεία δεδομένων) με ποσοστό ακρίβειας άνω του 90%. Τα δεδομένα της διατριβής που συνέλεξαν οι αισθητήρες και αφορούν τις ρωγμές, τις κοιλότητες οι οποίες δημιουργήθηκαν λόγω φθοράς του οδοστρώματος από την κίνηση των ελαστικών των οχημάτων, την προοδευτική αποσύνθεση σωματιδίων του οδοστρώματος, τις ανωμαλίες που δημιουργήθηκαν από την επίστρωση για επιδιόρθωση του οδοστρώματος, και τις λακκούβες, επικυρώθηκαν και αντιστοιχήθηκαν με εικόνες των επίσημων εγχειριδίων που χρησιμοποιούνται σήμερα από τα Υπουργεία Μεταφορών στις Ηνωμένες Πολιτείες της Αμερικής. Οι μελλοντικές διεργασίες για το συγκεκριμένο σύστημα θα αναπτύξουν κατώτατα όρια για την ανάπτυξη ενός συστήματος διαβάθμισης για τους πέντε προαναφερόμενους τύπους ανωμαλιών του οδοστρώματος και θα επεκτείνουν το προτεινόμενο σύστημα σε συμμετοχική ανίχνευση με τη χρήση στόλου οχημάτων.Περαιτέρω, η προτεινόμενη έρευνα θα διερευνήσει τη χρήση εφαρμογών των κινητών τηλεφώνων προκειμένου να βελτιωθεί η αξιολόγηση και η διαχείριση της κατάστασης του οδοστρώματος και, κατ’ επέκταση, θα εξετάσει τη δυνατότητα των δεδομένων των επιταχυνσιόμετρων και των γυροσκοπίων των κινητών τηλεφώνων, ώστε να συμβάλλουν στην αξιολόγηση της κατάστασης της επιφάνειας του οδοστρώματος του οδικού δικτύου. Δεδομένου, ότι τα σύγχρονα και τα μελλοντικά πρωτεύοντα δεδομένα θα είναι διαφορετικά σε σχέση με τα παραδοσιακά δεδομένα των οδοστρωμάτων, για να ξεπεραστεί αυτό το εμπόδιο, είναι συνετό να συγκεντρωθούν δεδομένα που προέρχονται από συγκεκριμένο αριθμό οχημάτων ανίχνευσης. The systematic management of pavements has become increasingly essential as pavement surfaces continue to age and deteriorate, and budgeting levels have decreased due to reduced finance capitals or increased competition for funds. The discussed research investigates the development of an innovative Geographic Information System (GIS)-based pavement monitoring system for the evaluation of the pavement surface condition of roadway networks. The thesis suggests a pavement monitoring system that gives the opportunity to pavement agencies to manage their pavements at the right moment and avoid constructing new ones. Pavement surface condition data can be collected and analyzed on a daily base from typical passenger cars and smartphones. The proposed methodology will achieve significant savings in expenditures for roadway pavement maintenance and rehabilitation, and in related impacts of roadway closures. Further, the proposed methodology will result in valuable savings in the data collection, in PMS-related platforms (including software purchase and installation, database building and system maintenance), as well as consulting services and employee training.The study explores the use of data, collected by sensors from smartphones and from automobiles’ (OBD-II) devices while vehicles are in movement, for the detection and classification of pavement surface anomalies. The smartphone-based data collection is complimented with robust regression analysis, ANN techniques, various algorithms and bagged trees classification models for classifying detected roadway anomalies. The proposed method and system architecture have already been in development, utilized four metrics in the analysis, and have been checked against five types of roadway anomalies, and validated against hundreds of roadways runs (relating to more than a 45000 of data points) with above 90% accuracy rate. Thesis sensors distress data of cracks, rutting, ravelling, patching and potholes were validated and corresponded against the images of the official surveys that agencies are currently using. Future work will develop threshold ranges for the development of a rating system for these five types of roadway anomalies and will extend the proposed system to participatory sensing by use of the fleet of vehicles.The research will further investigate the use of smartphone applications, in order to improve the roadway condition assessment and management of roadway pavements, and by extension, it will investigate the potential that connected smartphone’s accelerometers and gyroscopes data may contribute to monitoring the pavement surface condition of transport infrastructure. Given that contemporary and future primary datasets will be different in form from traditional pavement condition data, and in order to overcome this barrier, it is prudent that crowd-sourced data will be collected from a statistically significant number of probe-vehicles. Transportation agencies can enrich the condition and operation of their transportation networks by putting into practice a pavement monitoring system that operates on smartphone-based data collection. The proposed system has been field-tested, it is currently expanded to cover larger datasets and a higher number of roadway defect types, and has generated interest by the ministry of Transport, Communications and Works for possible implementation on Cyprus’s national roadway network.

State Transportation Agencies' utilization of work zone congestion mitigation strategies

Scipedia content — Tue, 26 Jan 2021 17:35:23 +0100

Collaborative and Context-Aware Applications for Intelligent and Green Transportation

Scipedia content — Tue, 26 Jan 2021 17:33:20 +0100

In this thesis, we present several context-aware and collaborative applications of electric and plug-in hybrid vehicles in the context of intelligent transportation systems, with a main focus on the design of control and optimisation algorithms to maximise the performance of such vehicles in different practical scenarios. This gives rise to four topics to be discussed in the thesis. The first topic focuses on the design of speed advisory systems for different road users. In Chapter 3, we present a framework for minimising the energy consumptions for a group of electric vehicles in a distributed manner. Using this framework, we extend the ideas of this design to the case of cyclists, where now we maximise the overall health benefits for a group of cyclists sharing a common route. In both cases, we apply a recently derived consensus mathematical result for solving both convex and quasi-convex optimisation problems with consensus constraints. The efficacy of our proposed algorithm is verified through many simulation studies. The second topic is concerned with a new design of the energy management system for plug-in hybrid electric vehicles (PHEVs) by taking into account the availability of the upcoming renewable energy generation. In Chapter 4, we introduce distributed algorithms for PHEVs to switch on/off their electric motors such that some utility functions can be maximised while achieving a demand and supply balance for power grids when vehicles travel back for recharging. This idea is then extended for the case of plug-in hybrid electric buses (PHEBs) in Chapter 5, focusing on maximising the environmental benefits of buses with some energy constraints to be satisfied. The third topic introduces a novel context-aware engine management system for PHEVs to optimally orchestrate switching between different operational modes so that the environmental benefits on pedestrians can be reached to a maximum. In Chapter 6, we present details of our design for such a system taking account of many factors in practice. We implement the proposed system in a hardware-in-the-loop platform, embedded with a real PHEV, to illustrate the efficacy of our proposed approach. The last topic investigates the ability of simple macroscopic information to identify changes in nominal urban traffic flows. In Chapter 7, we focus on using junction turning probabilities to infer the occurrence of anomalies in traffic patterns. Finally, several simulation studies are conducted in a popular mobility simulator to demonstrate the capabilities of our proposed method.

Quel avenir pour les véhicules utilitaires légers électriques ? : une analyse prospective du marché des vans électriques pour le transport de marchandises en ville

Scipedia content — Tue, 26 Jan 2021 17:29:44 +0100

Freight transport. The needs of freight transport companies are assessed through some forty interviews conducted in four European countries and analyzed in the light of innovation diffusion theory. These interviews highlight the operational and economic obstacles to the use of electric vehicles, which are linked to the technology itself but also to its novelty.A quantitative approach completes this study. It is based on a market share prediction model, which quantifies how economic and operational constraints evolve with technological developments. These constraints are measured by two indicators: the vehicle's range adequacy given its use and total cost of ownership (TCO) comparisons. An original feature of the model is that it treats the amount of subsidies for the purchase of an electric vehicle as an endogenous variable that dynamically adapts to market developments.In order to compensate for the lack of available data on commercial vehicle uses, a statistical model has been developed. This model makes the best use of data from a survey on light commercial vehicles in France, conducted by the statistical department of the Ministry of the Environment (SDES).These analyses confirm that the development of the electric vehicle market is not certain and that it is currently extremely dependent on public support. Even in scenarios of continued financial support from public administrations, exponential market growth is unlikely. Rather, the market will grow slowly for many years to come, the time for technology to overcome its8dependence on public financial support. For example, our reference scenario forecasts a 13% market share for electric vans in 2032; Le marché des véhicules électriques est animé par une dynamique très positive. Il s'agit cependant essentiellement d'un marché de niche. Il est donc légitime de s’interroger quant à son avenir.D'une part, cette dynamique est portée par de fortes préoccupations environnementales et bénéficie d'un large soutien des autorités publiques. Les constructeurs automobiles ont ces dernières années fortement investi dans cette technologie, les progrès technologiques sont rapides et offrent des perspectives intéressantes.D'autre part, des subventions conséquentes sont aujourd’hui nécessaires pour permettre aux véhicules électriques d’être compétitifs. Il est inévitable que ces subventions diminuent si le marché grandit. Deux mécanismes opposés sont donc en jeu et rendent incertain le développement du marché des véhicules électriques pour les années à venir.Notre recherche propose d'analyser ces mécanismes pour les véhicules utilitaires légers, et plus particulièrement pour le transport urbain de marchandises. Les besoins des entreprises de transport de marchandises sont évalués à travers une quarantaine d'entretiens, menés dans quatre pays européens et analysés à la lumière de la théorie de la diffusion de l'innovation. Ces entretiens mettent en évidence les obstacles opérationnels et économiques à l'utilisation de véhicules électriques, qui sont liés à la technologie elle-même mais aussi à sa nouveauté.Une approche quantitative complète cette étude. Elle s’appuie sur un modèle de prédiction de parts de marché, qui quantifie la façon dont les contraintes économiques et opérationnelles évoluent avec les développements technologiques. Ces contraintes sont mesurées par deux indicateurs: l'adéquation de l'autonomie du véhicule avec son usage et les comparaisons de coûts totaux de possession (TCO). Une originalité du modèle est qu’il traite le montant des subventions à l’achat d’un véhicule électrique comme une variable endogène, qui s’adapte dynamiquement aux évolutions du marché.Afin de compenser le manque de données disponibles sur les usages des véhicules utilitaires, un modèle statistique a été développé. Ce modèle permet d’exploiter au mieux les données d'une enquête sur les véhicules utilitaires légers en France, menée par le service de la donnée et des études statistiques (SDES) du Ministère de la Transition Écologique et Solidaire

The potential of social routing advice

Scipedia content — Tue, 26 Jan 2021 17:27:29 +0100

Travel information is expected by many scholars and practitioners alike to be successful in reducing traffic congestion and thereby improving road network efficiency. Yet, traditional (personalized) travel information aims at generating benefits to individual travellers, stimulating their personal optimization of their own route choices; it is well-known that this may lead to an inefficient user equilibrium. Examples on network efficiency have shown that in order to achieve system optimal network conditions, at least some travellers need to act non-selfish and take a detour to the benefit of others (i.e. the network as a whole). An important question in this regard is how to motivate those travellers to take this detour. This thesis deals with the problem of improving road network efficiency by stimulating social choice behaviour using social routing advice. Stated choice and revealed choice experiments provide insights into individual compliance behaviour, while network simulation indicates the resulting network impacts. Results show that travellers are sometimes willing to choose the social detour over their usual route. Travellers are willing to choose the social route when travel time sacrifices are not too large, when information messages are aiming at alleviating congestion as opposed to safety or environmental concerns, and when these messages are framed according to certain strategies that nudge travellers towards the social route, that reinforce social norms towards taking the social route or that educate travellers on the importance of taking the social route. Moreover, travellers are most likely to comply with the received advice when they are cooperatively oriented and when they make their choices in a non-habitual manner. As a result, network efficiency improves; structural congestion and unstable flows reduce, especially on major city roads. However, individual benefits will be marginal; the majority of travellers experience a travel time gain of less than two minutes. Finally, I show that the lower the compliance among travellers, the more social travellers need to compensate for the selfish behaviour of others by taking longer detours.

New strategies for the massive introduction of electric vehicles in the operation and planning of Smart Power Systems

Scipedia content — Tue, 26 Jan 2021 17:26:41 +0100

En el contexto actual, donde el calentamiento climático es cada vez más importante, existe la necesidad de limitar el consumo de combustibles fósiles. De esta manera, el transporte es uno de los sectores en los que más se están generando cambios en cuanto a la sostenibilidad. El vehículo eléctrico aparece como una solución para este cambio paulatino ya que no contamina localmente y su balance energético es muy eficiente. Así, se han propuesto diferentes programas para el crecimiento del vehículo eléctrico en el parque automotor. Sin embargo, el cambio de vehículos de gasolina por vehículos eléctricos genera desafíos en varios aspectos, como el impacto que ocasiona en la red eléctrica una implantación masiva: caídas de tensión, pérdidas de potencia, problemas con la calidad de la electricidad, inversiones importantes, etc. Se han planteado algunas soluciones en la parte operativa, pero muchas de ellas no han tomado en cuenta la flexibilidad de los usuarios, lo cual es muy importante para la adopción de vehículos eléctricos. De igual manera, en muchas ocasiones, en la literatura se asumen valores para ciertas variables (estado de carga, recorrido, tipo de batería, etc) que pueden cambiar según el comportamiento de cada usuario, lo que modificaría las previsiones realizadas. Finalmente, pocos trabajos han estudiado el impacto de lo vehículos eléctricos en redes eléctricas cuya gestión energética es más complicada debido a su aislamiento de una macrored y con alta penetración de energías renovables, como lo son las microredes. En este marco, esta tesis propone un enfoque novedoso en cuanto a la participación de los usuarios de vehículos eléctricos en la operación y planificación de diferentes sistemas eléctricos de potencia. Esta trata de algunos aspectos principales: disminución de costos de carga, participación en servicios de regulación, aprovechamiento de energía renovable, así como la planificación de generación de una microred incorporando vehículos eléctricos. En una primera parte, se presenta un análisis del vehículo eléctrico y su interacción en sistemas de potencia. De igual manera, se presentan los trabajos de investigación relacionados sobre la temática. En base al análisis de dichos trabajos, esta tesis propone una nueva metodología para optimizar la carga de los vehículos eléctricos. Se propone la participación de un nuevo agente del mercado eléctrico, el Agregador de vehículos eléctricos. Tendrá que gestionar la carga de dichos vehículos en una importante zona, coordinar con el operador de la red para evitar fallos y minimizar los costos de carga. De igual manera, se considera la diferente flexibilidad de los usuarios ya qu podrán escoger una tarifa que se adapte a su disponibilidad en espera y pagar el precio por aquello. La metodología ha sido aplicada a un caso de estudio a la red de Quito, Ecuador. Se propone también la participación en servicios de regulación, necesitando esta vez de usuarios que sean más flexibles al dejar su vehículo conectado a la red. Se considera las tarifas de la parte anterior para realizar dicho estudio. De igual manera, se aplicó al caso de estudio de la red de Quito, Ecuador. Con el crecimiento de las energías renovables, como solar y eólica, la gestión de la electricidad se vuelve más compleja. Con vistas a utilizar el exceso de energía renovable, se propone una tarifa de electricidad que permita al agregador de cargar los diferentes vehículos, tomando en cuenta precios bajos en periodos en donde la energía renovable esté en exceso. Finalmente, se plantea a planificación de generación de una microred que incluya la introducción masiva de vehículos eléctricos. Se aplicó al caso de las islas de Santa Cruz y Baltra, Galápagos, Ecuador, estudiando el impacto en los costos y en el medio ambiente de nueva generación y considerando la variación del precio del diésel debido a su incertidumbre. In the current context, where global warming is growing progressively, it is fundamental to limit fossil fuels consumption. Hence, transportation is one of the sectors in which several changes are occurring considering the sustainability. The Electric Vehicle appears as a new solution for this gradual change; it does not pollute locally and its energy's balance is very efficient. So, different programs have been proposed for the growth of electric vehicles in the automotive market. Nevertheless, the change from internal combustion vehicles to electric vehicles generates challenges in several aspects, such as the impact in the electric grid of a massive introduction of electric vehicles: voltage drops, power losses, quality of electricity issues, important investments, among others. Several solutions in operation have been formulated, but most of them do not consider the flexibility of users, which is a significant criterion for the electric vehicle acquisition. Moreover, in several works of the literature, many variables are assumed (stateof- charge, routes, type of battery, etc), which can vary significantly depending on the user, so also the results. Finally, few works have studied the impact of electric vehicles in very complex power systems, as the ones that are isolated from a macrogrid and because of significant penetration of renewable energy sources, such as microgrids. In this context, this thesis proposes a novel approach to the participation of the electric vehicle users in operation and planning of different electric power systems. This thesis is intended to cover various topics: charging costs decrease, regulation services participation, use of an excess of renewable energy, and the power generation planning of a microgrid considering the introduction of electric vehicles. In a first part, an analysis of the electric vehicle and its interaction with power systems is presented. Additionally, the principal works on the topic are summarized. Based on the analysis of these works, this thesis proposes a new methodology for optimizing the charge of electric vehicles. The participation of a new agent of the electricity market, the electric vehicle aggregator, is proposed. It has the ability to manage the charge of the electric vehicles in a zone with significant size, to coordinate with the grid operator in order to avoid troubles and to minimize charging costs. Furthermore, the different flexibility of electric vehicle users is considered because they will choose an EV customer choice product (CCP) that is adapted to their waiting needs and to the cost they can pay. The methodology has been applied to a case study in the grid of Quito, Ecuador. The participation in regulation services has been also considered to discuss this participation in Ancillary services. The CCPs from the part before are considered for performing such study but assuming more involvement from the electric vehicle users. The case study of Quito, Ecuador, was also studied. With the growth of renewable energies, such as solar and wind, the electricity management becomes more complicated. In order to use the excess of renewable energy, an EV charging mechanism for the aggregator is proposed, based on low prices when the renewable energy is in excess. Finally, a power generation planning for a microgrid is proposed, considering the massive introduction of electric vehicles. The case of the Santa Cruz and Baltra islands, Galapagos, Ecuador are studied to determine its costs and environmental impacts, based on diesel costs sensitivity studies to account for its uncertainty. En el context actual, on l'escalfament climàtic és cada vegada més important, hi ha la necessitat de limitar el consum de combustibles fòssils. El transport és un dels sectors en els quals més s'estan generant canvis pel que fa a la sostenibilitat. El vehicle elèctric apareix com una solució per a aquest canvi gradual ja que no contamina localment i el seu balanç energètic és molt eficient. Així, s'han proposat diferents programes per al creixement del vehicle elèctric al parc automotor. No obstant això, el canvi de vehicles de gasolina per vehicles elèctrics generen desafiaments en diversos aspectes, com son l'impacte que ocasiona a la xarxa elèctrica una implantació massiva: caigudes de tensió, pèrdues de potència, problemes amb la qualitat de l'electricitat, inversions importants, disminució de la vida útil dels transformadors, etc. S'han plantejat algunes solucions a la part operativa, però moltes d'elles no han tingut en compte la flexibilitat dels usuaris, la qual cosa és molt important per a l'adopció de vehicles elèctrics. De la mateixa manera, en moltes ocasions, en la literatura s'assumeixen valors per certes variables (estat de càrrega, recorregut, tipus de bateria, etc.) que poden canviar segons el comportament de cada usuari, el que modificaria les previsions realitzades. Finalment indicar que pocs treballs han estudiat l'impacte del que vehicles elèctrics en xarxes elèctriques on la gestió energètica és més complicada a causa del seu aïllament d'una macroxarxa i amb alta penetració d'energies renovables, com ho són les microxarxes. En aquest marc, aquesta tesi proposa un enfocament nou pel que fa a la participació dels usuaris de vehicles elèctrics en l'operació i planificació de diferents sistemes elèctrics de potència. Aquesta tracta alguns aspectes principals: disminució de costos de càrrega, participació en serveis de regulació, aprofitament d'energia renovable, així com la planificació de generació d'una microxarxa incorporant vehicles elèctrics. En una primera part, es presenta una anàlisi del vehicle elèctric i la seva interacció en sistemes de potència. De la mateixa manera, es presenten els treballs de recerca relacionats sobre la temàtica. En base a l'anàlisi d'aquests treballs, aquesta tesi proposa una nova metodologia per optimitzar la càrrega dels vehicles elèctrics. Es proposa la participació d'un nou agent del mercat elèctric, el Agregador de vehicles elèctrics. Haurà de gestionar la càrrega d'aquests vehicles en una important zona, coordinar amb l'operador de la xarxa per evitar fallades i minimitzar els costos de càrrega. De la mateixa manera es considera la diferent flexibilitat dels usuaris ja que podran escollir una tarifa que s'adapti a la seva disponibilitat en espera i pagar el preu per allò. La metodologia ha estat aplicat a un cas d'estudi a la xarxa de Quito, Equador. Es proposa també la participació en serveis de regulació, necessitant aquest cop d'usuaris que siguin més flexibles en deixar el seu vehicle connectat a la xarxa. Es consideren les tarifes de la part anterior per a realitzar dit estudi. De la mateixa manera, es va aplicar al cas d'estudi de la xarxa de Quito, Equador. Amb el creixement de les energies renovables, com solar i eòlica, la gestió de l'electricitat es torna més complexa. Amb vista a utilitzar l'excés d'energia renovable, es proposa un tarifa d'electricitat que permeti a l'agregador de carregar els diferents vehicles, especialment en períodes on l'energia renovable estigui en excés. Finalment, es planteja la planificació de generació d'una microxarxa que inclogui la introducció massiva de vehicles elèctrics. En concret, es va aplicar al cas de la illes de Santa Cruz i Baltra, Galápagos, Equador, estudiant l'impacte de la nova generació en els costos i en el medi ambient i considerant la variació del preu del dièsel, causa de la seva incertesa. Clairand Gómez, JM. (2018). New strategies for the massive introduction of electric vehicles in the operation and planning of Smart Power Systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/110971 TESIS

A systematic Mapping study of ADAS and Autonomous Driving

Scipedia content — Tue, 26 Jan 2021 17:22:05 +0100

Nowadays, autonomous driving revolution is getting closer to reality. To achieve the Autonomous driving the first step is to develop the Advanced Driver Assistance System (ADAS). Driver-assistance systems are one of the fastest-growing segments in automotive electronics since already there are many forms of ADAS available. To investigate state of art of development of ADAS towards Autonomous Driving, we develop Systematic Mapping Study (SMS). SMS methodology is used to collect, classify, and analyze the relevant publications. A classification is introduced based on the developments carried out in ADAS towards Autonomous driving. According to SMS methodology, we identified 894 relevant publications about ADAS and its developmental journey toward Autonomous Driving completed from 2012 to 2016. We classify the area of our research under three classifications: technical classifications, research types and research contributions. The related publications are classified under thirty-three technical classifications. This thesis sheds light on a better understanding of the achievements and shortcomings in this area. By evaluating collected results, we answer our seven research questions. The result specifies that most of the publications belong to the Models and Solution Proposal from the research type and contribution. The least number of the publications belong to the Automated…Autonomous driving from the technical classification which indicated the lack of publications in this area.

Robust Global Localization Using GPS and Aircraft Signals

Scipedia content — Tue, 26 Jan 2021 17:18:41 +0100

Localization is a fundamental technology embedded — often unbeknownst to users — in many devices and services. First, this book reveals how localization systems are driving modern society. The core focus is then on the Global Positioning System (GPS), which is constantly rising in importance due to its global availability and low receiver cost. Still, high energy consumption and susceptibility to fake or reflected signals are challenges for GPS receivers. The limited endurance of battery-powered GPS receivers can be addressed by snapshot receivers which require as little as one millisecond of received satellite signals to determine their location. Using short signals reduces the active time and thus the energy consumption of a GPS receiver drastically. But short signals reduce the received signal energy, which impairs the localization robustness. The collective detection maximum likelihood method performs well with short signals. Furthermore, a tiny and low power snapshot GPS receiver hardware design allows location tracking for months or years using a coin cell. Spoofed GPS satellite signals pose a threat to an increasing number of critical systems relying on GPS. Determining multiple likely localization solutions instead of only one enables correct receiver localization despite malicious signals. Finally, an experimental localization system is presented that leverages status messages transmitted by aircraft. It aims at combining the ubiquitous availability and low receiver cost of GPS with the high signal strength of local localization systems like those based on WiFi or LTE signals. As such, it gives the prospect of robust and possibly indoor localization without the high setup costs of short- range localization systems. This book is suitable for readers with a technical background, but no prior knowledge of localization systems. Readers familiar with GPS can skip the introductory chapters and directly dive into the advanced material.

Potential benefits of load flexibility: a focus on the future Belgian distribution system

Scipedia content — Tue, 26 Jan 2021 17:17:44 +0100

Since the last United Nations Climate Change Conference in 2015 in Paris (the COP 21), world leaders acknowledged climate change. There is no need any more to justify the switch from fossil fuel-based to renewable energy sources. Nevertheless, this transition is far from being straightforward. Besides technologies that are not yet mature -- or at least not always financially viable in today's economy -- the power grid is currently not ready for a rapid and massive integration of renewable energy sources. A main challenge for the power grid is the inadequacy between electric production and consumption that will rise along with the integration of such sources. Indeed, due to their dependence on weather, renewable energy sources are intermittent and difficult to forecast with today's tools. As a commodity, electricity is a quite distinct good for which there must be perfect adequacy of production and consumption at all time and characterized by a very inelastic demand. High shares of renewable energy sources lead to high price volatility and a higher risk to jeopardize the security of supply. Additionally, the switch to renewable energy sources will lead to an electrification of loads and transportation, and thus the emergence of new higher-consumption loads such as electric vehicles and heat pumps. These new and higher-consumption loads, combined with the population growth, will cause over-rated power load increases with less predictable load patterns in the future.This work focuses on issues specific to the distribution power grid in the context of the current energy transition. Traditional low-voltage grids are perhaps the most passive circuits in power grids. Indeed, they are designed primarily using a fit and forget approach where power flows go from the distribution transformer to the consumers and no element has to be operated or regularly managed. In fact, low-voltage networks completely lack observability due to very low monitoring. The distribution grid will especially undergo drastic changes from this energy transition. Distributed sources and new high-consumption -- and uncoordinated -- loads result in new power flow patterns, as well as exacerbated evening peaks for which it is not designed. The consequences are power overloads and voltage imbalances that deteriorate grid components, such as a main asset like the medium-to-low voltage transformer. Additionally, the distribution grid is characterized by end-users that pay a price for electricity that does not reflect the grid situation -- that is, mostly constant over a year -- and allow little to no actions on their consumption.These issues have motivated authorities to propose a global approach to ensure security of electricity supply at short and medium-term. The latter requires, among others, the development of demand response programs that encourage users to take advantage of load flexibility. First, we propose adequate electricity pricing structures that will allow users to unlock the potential of such demand response programs; namely, dynamic pricings combined with a prosumer structure. Second, we propose a fast and robust two-level optimization, formulated as a mixed-integer linear program, that coordinates flexible loads. We focus on two types of loads; electric vehicles and heat pumps, in an environment with solar PV panels. The lower level aims at minimizing individual electricity bills while, at the second level, we optimize the power load curve, either to maximize self-consumption, or to smoothen the total power load of the transformer. We propose a parametric study on the trade-off between only minimizing the individual bills versus only optimizing power load curves, which have proven to be antagonist objectives. Additionally, we assess the impact of the rising share of flexible loads and renewable energy sources for scenarios from today until 2050. A macro-analysis of the results allows us to assess the benefits of load flexibility for every actor of the distribution grid, and depending on the choice of a pricing structure. Our optimization has proved to prevent evening peaks, which increases the lifetime of the distribution transformer by up to 200%, while individual earnings up to 25% can be made using adequate pricings. Consequently, the optimization significantly increases the power demand elasticity and increases the overall welfare by 10%, allowing the high shares of renewable energy sources that are foreseen.

Doctorat en Sciences de l'ingénieur et technologie

info:eu-repo/semantics/nonPublished

Factors Influencing the Purchase Willingness towards Electric Vehicles in China

Scipedia content — Tue, 26 Jan 2021 17:16:16 +0100

As China is facing environmental problems, they are producing positive policies in order to stimulate the sales of electric vehicles. In addition, China is one of the largest electric vehicle markets in the world and the electric vehicles market has a promising growth potential. In light of this, this thesis aims to investigate the factors affecting Chinese consumers’ willingness to purchase electric vehicles. This thesis draws on rational choice theory to analyze the six determining factors including driving range of electric vehicles, charging infrastructure, purchase cost, government financial incentives, individual environmental awareness and perceived social influence, as electric vehicles are not cheap goods and make consumers take full consideration before buying. This study adopts a quantitative approach and conducts a survey to investigate this topic. Based on 249 online questionnaires from Chinese consumers, this study employs SPSS to conduct a regression analysis to test the six determining factors. The empirical results indicate that charging infrastructure, government financial incentives, individual environmental awareness and perceived social influence have significant impact on Chinese consumers’ willingness to purchase electric vehicles, while our results do not show that the driving range of electric vehicles and purchase cost matters in influencing Chinese consumers’ willingness to purchase electric vehicles. Meanwhile, this study contributes to the research on the consumption of electric vehicles by providing an empirical context of China, considering rational choice theory and understanding perceived social influence. Also, this study provides relevant suggestions to electric vehicle manufacturers and the Chinese government about how to encourage the Chinese to adopt electric vehicles in China. Keywords: Electric Vehicles, Willingness to purchase, SPSS, Rational choice theory, Chin

Vehicle Tracking Through Vision - Millimeter Wave Doppler Shift Fusion

Scipedia content — Tue, 26 Jan 2021 17:12:54 +0100

von Martín Trullenque Ortiz Arbeit an der Bibliothek noch nicht eingelangt - Daten nicht geprueft Technische Universität Wien, Diplomarbeit, 2019

Link Criticality Characterization for Network Optimization : An approach to reduce packet loss rate in packet-switched networks

Scipedia content — Tue, 26 Jan 2021 17:10:39 +0100

Network technologies are continuously advancing and attracting ever-growing interests from the industry and society. Network users expect better experience and performance every day. Consequently, network operators need to improve the quality of their services. One way to achieve this goal entails over-provisioning the network resources, which is not economically efficient as it imposes unnecessary costs. Another way is to employ Traffic Engineering (TE) solutions to optimally utilize the current underlying resources by managing traffic distribution in the network. In this thesis, we consider packet-switched Networks (PSN), which allows messages to be split across multiple packets as in today’s Internet. Traffic engineering in PSN is a well-known topic yet current solutions fail to make efficient utilization of the network resources. The goal of the TE process is to compute a traffic distribution in the network that optimizes a given objective function while satisfying the network capacity constraints (e.g., do not overflow the link capacity with an excessive amount of traffic). A critical aspect of TE tools is the ability to capture the impact of routing a certain amount of traffic through a certain link, also referred as the link criticality function. Today’s TE tools rely on simplistic link criticality functions that are inaccurate in capturing the network-wide performance of the computed traffic distribution. A good link criticality function allows the TE tools to distribute the traffic in a way that it achieves close-to-optimal network performance, e.g., in terms of packet loss and possibly packet latencies. In this thesis, we embark upon the study of link criticality functions and introduce four different criticality functions called: 1) LeakyCap, 2) LeakyReLU, 3) SoftCap, and 4) Softplus. We compare and evaluate these four functions with the traditional link criticality function defined by Fortz and Thorup, which aims at capturing the performance degradation of a link given its utilization. To assess the proposed link criticality functions, we designed 57 network scenarios and showed how the link criticality functions affect network performance in terms of packet loss. We used different topologies and considered both constant and bursty types of traffic. Based on our results, the most reliable and effective link criticality function for determining traffic distribution rates is Softplus. Softplus outperformed Fortz function in 79% of experiments and was comparable in the remaining 21% of the cases. Nätverksteknik är ett område under snabb utveckling som röner ett stort och växande intresse från såväl industri som samhälle. Användare av nätverkskommunikation förväntar sig ständigt ökande prestanda och därför behöver nätverksoperatörerna förbättra sina tjänster i motsvarande grad. Ett sätt att möta användarnas ökade krav är att överdimensionera nätverksresurserna, vilket dock leder till onödigt höga kostnader. Ett annat sätt är att använda sig av trafikstyrninglösningar med målet att utnyttjade tillgängliga resurserna så bra som möjligt. I denna avhandling undersöker vi paketswitchade nätverk (PSN) i vilka meddelanden kan delas upp i multipla paket, vilket är den rådande paradigmen för dagens Internet. Ä ven om trafikstyrning (TS) för PSN är ett välkänt ämne så finns det utrymme för förbättringar relativt de lösningar som är kända idag. Målet för TS-processen är att beräkna en trafikfördelning i nätverket som optimerar en given målfunktion, samtidigt som nätverkets kapacitetsbegränsningar inte överskrids. En kritisk aspekt hos TS-verktygen är förmågan att fånga påverkan av att sända en viss mängd trafik genom en specifik länk, vilket vi kallar länkkritikalitetsfunktionen. Dagens TS verktyg använder sig av förenklade länkkritikalitetsfunktioner som inte väl nog beskriver trafikfördelningens påverkan på hela nätverkets prestanda. En bra länkkritikalitetsfunktion möjliggör för TS-verktygen att fördela trafiken på ett sätt som närmar sig optimal nätverksprestanda, till exempel beskrivet som låg paketförlust och låg paketlatens. I denna avhandling undersöker vi länkkritikalitetsfunktioner och föreslår fyra olika funktioner som vi kallar 1) LeakyCap, 2) LeakyReLU, 3) SoftCap, och 4) Softplus. Vi jämför och utvärderar dessa fyra funktioner och inkluderar även klassiska länkkritikalitetsfunktioner som Fortz och Thorup, vilka avser fånga prestandadegraderingen av en länk över graden av utnyttjande.Vi har undersökt 57 olika nätverksscenarier för att bestämma hur de olika länk kritikalitets funktionerna påverkar nätverksprestanda i form av paketförlust. Olika topologier har använts och vi har studerat såväl konstant som stötvis flödande trafik. Enligt våra resultat är Softplus den mest tillförlitliga och effektiva länkkritikalitetsfunktionen för att fördela trafiken i ett nätverk. Softplus presterade bättre än Fortz i 79% av våra tester, och var jämförbar i övriga 21%.

Rendre possible l'ingénierie de trafic dans les réseaux avec routage par segment

Scipedia content — Tue, 26 Jan 2021 17:07:47 +0100

Most major operators use MPLS technology to manage their network via signalling and label distribution protocols. However, these protocols are complex to deploy, maintain and troubleshooting is often very difficult. The IETF has initiated the standardization of a segment routing architecture based on a simple control plane, lightweight, easyto-manage and instantiated on MPLS or IPv6. This architecture is based on the concept of source routing, in which the packet header carries the indications of the path to follow to reach its destination. Suitable for simple use cases and natively resistant to failure, more complex use cases require the resolution of technological issues for which we offer several solutions.In this thesis carried out within Orange Labs, we were interested in the instantiation of the Segment Routing architecture on the MPLS transfer plan and more particularly in traffic engineering, particularly with resource reservation. We have proposed solutions to the problems related to the hardware limitation of current routers that do not allow the expression of all constrained paths. This work is divided into two parts : (i) the proposal of algorithms for computing and encoding segment routing paths in order to bypass hardware limitations. (ii) the definition of architectural requirements and the construction of a functional proof of concept. Finally, this thesis proposes new research issues to consolidate traffic engineering tools for segment routing.; La majorité des grands opérateurs utilise la technologie MPLS pour gérer leur réseau via des protocoles de signalisation et de distributions de labels. Or, ces protocoles sont complexes à déployer, à maintenir et la résolution des pannes est souvent très difficile. L'IETF a initié la standardisation d'une architecture de routage par segments (Segment Routing) s'appuyant sur un plan de contrôle simple, léger, facile à gérer et instanciée sur MPLS ou IPv6. Cette architecture repose sur le concept de routage à la source, dans lequel l'en-tête des paquets transporte les indications du chemin à suivre pour atteindre sa destination. Adapté aux cas d'usages simples et offrant nativement une résistance aux pannes, les cas d'usages plus complexes exigent de résoudre des verrous technologiques pour lesquels nous proposons plusieurs solutions. Dans cette thèse effectuée au sein d'Orange Labs, nous nous sommes intéressés à l'instanciation de l'architecture Segment Routing sur le plan de transfert MPLS et plus particulièrement à l'ingénierie de trafic, notamment avec réservation de ressources. Nous avons proposé des solutions aux problèmes liés à la limitation matérielle des routeurs actuels ne permettant pas l'expression de tous les chemins contraints. Ce travail est divisé en deux parties : (i) la proposition d'algorithmes de calcul et d'encodage de chemins de routage par segment afin de contourner les limitations matérielles. (ii) la définition des exigences architecturales et la construction d'une preuve de concept fonctionnelle. Enfin, cette thèse propose de nouvelles pistes d'études afin de consolider les outils d'ingénierie de trafic pour le routage par segment.

Modeling heterogeneous vehicular traffic for intelligent transport system applications

Scipedia content — Tue, 26 Jan 2021 17:04:06 +0100

This dissertation models and analyzes heterogeneous traffic flow, with a particular focus on mixed traffic flow consisting of cars and two-wheelers. The increase in traffic congestion induces commuters to switch to powered two wheelers (PTWs), i.e. motorcycle, mopeds and scooters, because of their high maneuverability and space efficiency. The growth in number of PTWs, combined with their unique mobility features, results in complex traffic characteristics which are difficult to recreate with the existing modeling approaches. We develop an analytical model that can accurately reproduce the traffic features in a mixed flow of cars and PTWs. The traffic stream is decomposed into two vehicle classes, PTWs and cars. The fundamental properties are derived by employing a porous flow approach. It is assumed that the speed of a vehicle class is dictated by the physical and motion properties of the vehicle class, and the distribution of free spaces on the road. We propose an approximation method to derive the free-space distribution. In order to explore broader aspects of the traffic flow characteristics, notably required by intelligent transport system (ITS) applications, we formulate the model in the Lagrangian and the Eulerian frameworks. Further, we provide a numerical method for the discretization of the mathematical model. We analyze the flow characteristics of mixed PTWs and cars traffic and identify important properties, which give insights for future ITS solutions and traffic policy makers. The applicability of the model for different ITS applications is illustrated. Finally, the developed model is validated using a microsimulation tool.; Cette dissertation modélise et analyse les flux de trafic hétérogènes, avec une attention particulière portée à la circulation de voitures et de deux-roues. L'augmentation du nombre de congestions de trafic a forcé les personnes désirant se déplacer à se diriger vers les le deux-roues (appelé ici PTWs = powered two wheelers), comme les motos, les mopeds et les scooters, du fait de leur facilité de manoeuvre et leur efficacité dans l'espace. L'augmentation du nombre de PTWs combinée au caractère unique de certaines de leurs fonctionnalités a résulté en un trafic complexe, donc les particularités sont difficiles à recréer avec les approches de modélisation existantes. Nous développerons ici un modele analytique permettant de reproduire de manière pertinente les particularités d'un flux de véhicules mêlant à la fois les voitures et les deux-roues. Le trafic se décompose en deux classes de véhicules : les PTWs et les voitures. Les propriétés fondamentales sont déduites en employant une approche "porous flow". On suppose que la vitesse d'un véhicule d’une certaine classe est dictée par les propriétés physiques et motrices du véhicule, ainsi que la distribution d'espace vide sur la route. Nous proposons une méthode d'approximation pour dériver la distribution d'espace vide. Dans le but d'explorer plus largement les caractéristiques du flux de trafic notamment requis par les applications de système de transport intelligent (ITS), nous formulons le modèle dans les cadres lagrangien et eulérien. Puis, nous feront appel à une méthode numérique pour la discrétisation du modèle mathématique. Se basant sur le modèle développé nous analyserons les caractéristiques du flux de trafic pour en identifier les propriétés les plus importantes qui nous permettrons de prédire de futures ITS applications et d'organisations du trafic. La possibilité d'appliquer le modèle pour les différentes ITS applications est illustrée par des exemples. Finalement, le modèle développé est validé à l'aide de l'outil de microsimulation.

The Present and the Future of Fare-Free Public Transport and Sustainable Public Transport : The Cases of Avesta and Tallinn and The Visions for Luxembourg and Uppsala

Scipedia content — Tue, 26 Jan 2021 17:03:04 +0100

This research intends to illuminate the concept and application of the public policy named fare -free public transport (FFPT), using the cases of Avesta and Tallinn and analysing future applicability of it in the cases of Luxembourg and Uppsala city. The analysis explores the fare-free public transport policy and the theory of sustainable transport. The study presents the different benefits of the policy and its limitations, and how the FFPT is connected to sustainable transport and sustainable development theories and application. Through a case study analysis based in literature review, the analysis of both cities wants to elucidate the application of the FFPT as one important policy tool within cities both for the environment and for the people, and how the policy can develop in the future. Considering this, the presented research also opens the possibility of expansion of the policy to other cities and countries.

Identifying the challenges faced by a private bus operator

Scipedia content — Tue, 26 Jan 2021 17:02:14 +0100

MBA, North-West University, Potchefstroom Campus, 2019 The present economic climate in which public transport companies operate is highly competitive and presents various challenges that hinder the growth of many operators. The public transport sector includes both subsidised and non-subsidised operators, and operators in the formal sector are more regulated than operators in the informal sector. Considering the resulting great variation in the operational environments within which operators function, external factors may have as much influence on the management of the company as internal factors. Therefore, it is beneficial for companies to identify the challenges that affect the industry of operators in the private sector, specifically bus operators. While various studies have been conducted on either the informal sector or the subsidised sector within the transport industry and the challenges operators face, literature on crucial factors influencing bus operators, particularly in the private sector, is lacking. This knowledge gap prevents the operators in this sector from remaining competitive and viable in the future. This study will enable managers and owners of passenger transport companies in the private bus operators sector to recognise the challenges faced in order to strategically align policies and operational strategies for future sustainability. This mini-dissertation is based on an analytical study that was conducted to identify the challenges faced by a private bus operator, and thereby offering insight into the operating environment. The findings and insights around these challenges will help management identify and incorporate operational and strategic elements into their short and medium term strategies that will secure a more sustainable continuation of business for their company. This study consists of four chapters. Chapter 1 provides the nature and the scope of the study, the background to the study, the research problem, objectives, methodology, and limitations. Chapter 2 provides a theoretical literature review of the public transport industry in South Africa and the challenges bus operators face. Chapter 3 involves an empirical review and content analysis. Lastly, Chapter 4 includes an overall overview and conclusion of the study, and recommendations for future research. Master

Towards a Pluralistic Epistemology: Understanding the Future of Human-Technology Interactions in Shipping

Scipedia content — Tue, 26 Jan 2021 16:59:30 +0100

The rapid advance of technologies is revolutionizing the way people work and transforming society into a digital world. In the shipping domain, many innovative technical systems have been designed and developed in the past decades, aiming to enable the maritime users to achieve the goal of safety, efficiency and effectiveness. The introduction of advanced technologies into workplaces that are intended to aid humans have also created unprecedented challenges. As their workplaces are inundated with new artefacts that cause confusion and information overloading, human users frequently find themselves in a supporting role to serve technology, being responsible for automation issues and blamed for “human errors” that sometimes result in tragic results. Today’s work in shipping is generally getting more distributed, complex and demanding. These challenges are closely associated with the design and use of technologies. Human-technology interactions in the context of sociotechnical systems has become an important research topic. It explores the relation between humans and machines to illustrate how interface design could address the human limitations, shape social interactions and provide ecological implications. This thesis considers the context of the shipping domain to investigate the impact of innovative technology, design issues and opportunities in various projects that attempt to increase safety or/and efficiency. The exploration and discourse in these applied projects are positioned in sociotechnical systems which include human, technology and organisational constituents. The thesis aims to achieve a deeper understanding of human-technology interactions from psychological, sociological and ecological perspectives, reflecting the ways in which technology interacts with humans. It aims to form a pluralistic epistemology to provide design implications and enlighten knowledge and organisational management within sociotechnical systems. The results have identified many issues related to situation awareness, attention and automation bias. It suggests the importance of adapting interfaces to the human limitations and accommodating the context change to support decision making. Perspectives of Activity Theory, distributed cognition and situated learning have high reference value in human-computer interaction research, providing insightful understanding about the nature of knowledge and interaction design, particularly how tool mediation could facilitate social interaction. In addition, technology-centric design that only concerns “user-interface” interaction is identified having significant limitations in complex systems. “Human errors” and organisational failures should be perceived via a holistic thinking. The results have presented the importance of adopting pluralistic approaches to understand the sociological factors and the nature of the work that is undergoing transitions along the shipping industry’s ecology. Overall, the thesis has identified the need to go beyond the pure cognitivist approach to better understand the complexity of human-computer interaction and human factors research, forming a deepened understanding towards an emerging interdisciplinary language of sociotechnical systems. To truly contribute to safety, efficiency, effectiveness and sustainability, it is critical to develop a pluralistic epistemology and a comprehensive human-centric vision regarding design and technological innovation in the digital revolution.

Control and communication systems for automated vehicles cooperation and coordination

Scipedia content — Tue, 26 Jan 2021 16:57:50 +0100

Mención Internacional en el título de doctor The technological advances in the Intelligent Transportation Systems (ITS) are exponentially improving over the last century. The objective is to provide intelligent and innovative services for the different modes of transportation, towards a better, safer, coordinated and smarter transport networks. The Intelligent Transportation Systems (ITS) focus is divided into two main categories; the first is to improve existing components of the transport networks, while the second is to develop intelligent vehicles which facilitate the transportation process. Different research efforts have been exerted to tackle various aspects in the fields of the automated vehicles. Accordingly, this thesis is addressing the problem of multiple automated vehicles cooperation and coordination. At first, 3DCoAutoSim driving simulator was developed in Unity game engine and connected to Robot Operating System (ROS) framework and Simulation of Urban Mobility (SUMO). 3DCoAutoSim is an abbreviation for "3D Simulator for Cooperative Advanced Driver Assistance Systems (ADAS) and Automated Vehicles Simulator". 3DCoAutoSim was tested under different circumstances and conditions, afterward, it was validated through carrying-out several controlled experiments and compare the results against their counter reality experiments. The obtained results showed the efficiency of the simulator to handle different situations, emulating real world vehicles. Next is the development of the iCab platforms, which is an abbreviation for "Intelligent Campus Automobile". The platforms are two electric golf-carts that were modified mechanically, electronically and electrically towards the goal of automated driving. Each iCab was equipped with several on-board embedded computers, perception sensors and auxiliary devices, in order to execute the necessary actions for self-driving. Moreover, the platforms are capable of several Vehicle-to-Everything (V2X) communication schemes, applying three layers of control, utilizing cooperation architecture for platooning, executing localization systems, mapping systems, perception systems, and finally several planning systems. Hundreds of experiments were carried-out for the validation of each system in the iCab platform. Results proved the functionality of the platform to self-drive from one point to another with minimal human intervention. Los avances tecnológicos en Sistemas Inteligentes de Transporte (ITS) han crecido de forma exponencial durante el último siglo. El objetivo de estos avances es el de proveer de sistemas innovadores e inteligentes para ser aplicados a los diferentes medios de transporte, con el fin de conseguir un transporte mas eficiente, seguro, coordinado e inteligente. El foco de los ITS se divide principalmente en dos categorías; la primera es la mejora de los componentes ya existentes en las redes de transporte, mientras que la segunda es la de desarrollar vehículos inteligentes que hagan más fácil y eficiente el transporte. Diferentes esfuerzos de investigación se han llevado a cabo con el fin de solucionar los numerosos aspectos asociados con la conducción autónoma. Esta tesis propone una solución para la cooperación y coordinación de múltiples vehículos. Para ello, en primer lugar se desarrolló un simulador (3DCoAutoSim) de conducción basado en el motor de juegos Unity, conectado al framework Robot Operating System (ROS) y al simulador Simulation of Urban Mobility (SUMO). 3DCoAutoSim ha sido probado en diferentes condiciones y circunstancias, para posteriormente validarlo con resultados a través de varios experimentos reales controlados. Los resultados obtenidos mostraron la eficiencia del simulador para manejar diferentes situaciones, emulando los vehículos en el mundo real. En segundo lugar, se desarrolló la plataforma de investigación Intelligent Campus Automobile (iCab), que consiste en dos carritos eléctricos de golf, que fueron modificados eléctrica, mecánica y electrónicamente para darle capacidades autónomas. Cada iCab se equipó con diferentes computadoras embebidas, sensores de percepción y unidades auxiliares, con la finalidad de transformarlos en vehículos autónomos. Además, se les han dado capacidad de comunicación multimodal (V2X), se les han aplicado tres capas de control, incorporando una arquitectura de cooperación para operación en modo tren, diferentes esquemas de localización, mapeado, percepción y planificación de rutas. Innumerables experimentos han sido realizados para validar cada uno de los diferentes sistemas incorporados. Los resultados prueban la funcionalidad de esta plataforma para realizar conducción autónoma y cooperativa con mínima intervención humana. Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y Automática Presidente: Francisco Javier Otamendi Fernández de la Puebla.- Secretario: Hanno Hildmann.- Vocal: Pietro Cerri

Impacts of Automated Driving on Health and Quality of Life:Master's thesis

Scipedia content — Tue, 26 Jan 2021 16:52:37 +0100

utomated driving is one of the current hype phenomena generating widespread interest. Automated vehicles are a growing topic of discussion in both the academic and gray literature. Although fully automated vehicles are still far in the future, various levels of automation-featured vehicles are gradually gaining ground in road traffic. Impact assessment of automated driving promotes the development of automated systems and support decision-making in the field of transport. VTT Technical Research Centre of Finland Ltd. has studied the impacts of transport and mobility for decades, and has produced impact analyses with a broad scope in this field. The impact assessment of automated driving has recently seen further developments; this thesis continues the work and expands it to the themes of health and quality of life. "br/""br/"This thesis aimed to explore the impacts of transport and mobility on individuals' health and perceived quality of life and, further, to exploit the findigs under the domain of automated driving. One of the main objectives was to identify potential pathways of action from the introduction of automated driving to its health implications. The study was conducted in three phases: First, a review was done of the extant literature. Second, a conceptual framework for transport and its implications for health and quality of life was constructed with the help of a literature study and insights from specialists in diverse fields of health and transport. Third, the framework and supporting literature were used to formulate the potential pathways of action mentioned above. Finally, the results were discussed in a work group to ensure the validity and reliability of the results. The thesis process was iterative; i.e. the results from the literature and specialist interviews were utilized throughout the work right from the start. "br/""br/"This thesis has three key results. First, it provides a comprehensive and worthwhile overview of the concepts of health and quality of life in the context of transport and mobility, which can be used to support future discussion and research. The second key result is the illustrative conceptual framework, which provides insights into transport and its health implications. Finally, potential pathways from the introduction of automated driving to its impacts on health and quality of life are presented. Understanding these pathways to impact will not only support further development and decision-making; it will also help pinpoint future topics of research. One of these will be assessing the direction and magnitude of the potential impacts of automated driving.

Evaluation of silicon carbide power electronic components for hybrid and electric vehicles

Scipedia content — Tue, 26 Jan 2021 16:46:13 +0100

continuously growing penetration of electric (EV) and hybrid electric (HEV) vehicles, reinforced by the need for increased energy savings, drove the research towards power electronic components with superior material properties. Wide-bandgap (WBG) power semiconductor materials such as Silicon Carbide (SiC) offer significant improvements in power converter’s performance as they allow higher operating voltage, higher switching frequency and higher maximum operating temperature. As a consequence, it is expected to be utilized in traction DC-DC converters where high efficiency, high power density and lower cooling requirements are desired while, simultaneously, achieving significa nt reductions in the total weight and volume of the powertrain. The improved features introduced by SiC MOSFETs on DC-DC converter topologies employed in EVs and HEVs are investigated and experimentally verified. Initially, a non-isolated half-bridge DC-DC converter topology is designed with operating principles that correspond to a converter found on energy management systems of HEVs or fuel cell vehicles. The operating principle of the converter is presented and the bi-directional flow of energy aspect is explained. Subsequently, the design has been modelled and evaluated on a simulation software that considered the operating stages of the converter by also accounting for the gate driving circuit and the predefined cooling requirements. Finally, a test prototype was built in custom-made printed circuit board (PCB) and validated in terms of reliable operation and circuit efficiency. The benefits from utilizing SiC power semiconductors are presented under constant 24 V loading conditions and 80 kHz switching frequency. A constant voltage was maintained through automatically modulating the gate driving signal, whereas an efficiency of around 96% was achieved due to fast switching times introduced by SiC MOSFETs and thus the reduced switching losses. The efficie ncy of the system is dependable on the MOSFET operating performance and therefore an exposure of the transistors in environmental conditions was considered for each individual SiC MOSFET provided by different suppliers. Significant attention has been paid to rapid temperature change, extreme humidity, mechanical vibration and accelerated ageing tests that aim to address possible degradation and defects in the SiC material. The effect of the testing process was examined in component-level, by assessing the electrical characteristics of the SiC MOSFETs, as well as in converter-level by evaluating potential efficiency reductions and operating flaws. Finally, verification of the conditions under which each individual change occurred is of equal importance for prospective improvements in the transistor and converter alike.

Modeling and Analysis of the Interaction of Batteries and Power Electronic Converters

Scipedia content — Tue, 26 Jan 2021 16:45:57 +0100

This thesis deals with the interaction of batteries and power electronic converters in automotive applications. Even if the additional heating caused by (unwanted) alternating currents is disregarded, there has been a concern that alternating currents can be harmful for batteries. For that reason, alternating currents can be filtered using capacitors and/or by sophisticated hardware. In this work, the concern whether alternating currents are harmful to batteries is studied particular focus on large, lithium-ion cells for use in automotive applications.First, the harmonic content in the battery current of two, commercial hybrid-electric busses were measured and analysed. The most prominent harmonic had a peak magnitude higher than 10% of the maximum direct current level (160 A) arising at frequencies below 150 Hz. The maximum amplitude detected of a harmonic caused by the voltage source converter’s switching action was around 10 A and occurred at a frequency of 2 kHz. An experimental setup with alternating current capability for evaluating large lithium-ion cells has been designed and built. Twelve lithium-ion cells were cycled at a rate if 1 C during approximately 2000 cycles (corresponding to approximately one year). The cells were cycled with an superimposed alternating current of 1 Hz, 100 Hz, or 1 kHz while the rest of the cells were cycled with direct current (only), injected with alternating current (only), or no current at all (calendar aging). No negative effects caused by the alternating current was identified in terms of capacity fade and power fade for the tested lithium-ion cells. A comparison between sinusoidal current-ripple charging and conventional constant-current constant-voltage charging was also carried out. Three lithium-ion cells were cycled (ten times) with different ac currents superimposed during charge. The results were analyzed statistically and no significant improvements in terms of charging time or charging efficiency were observed in any of the charging tests using an superimposed ac current. The injection of alternating currents into batteries for heating purposes has also been studied and a control method for battery heating using an ac current was proposed. The proposed controller is applicable regardless of the LIB’s subsequent impedance nature (capacitive, inductive or resistive). Further, a design process for the generation of magnified alternating currents in dc-dc converters was presented. By matching the switching frequency with the frequency where the LCL filter and the battery resonate, the current flowing in the semiconductors and the switching frequency could be reduced. In a small experimental setup using a single lithium-ion cell, using an LCL-resonant circuit and a full bridges witch arrangement, magnifications of up to 15.7 were reached. This allowed for a loss reduction in the semiconductors of up to 75%, when compared to an equivalent dc-dc converter enabled to produce anon-magnified ac current. "p"QC 20190517

Electric roads as future road transport : A study of Electric Road System (ERS) to facilitate sustainable road transport for passenger cars

Scipedia content — Tue, 26 Jan 2021 16:43:52 +0100

Sweden is a geographically large and sparsely populated country, with a need for road transport for individuals as well as for logistics. Domestic road transport largely contributes to air pollutions, where passenger cars account for the largest share. Looking ahead, the present rate of reduction of emissions is not enough to reach the climate targets of a fossil free transport sector. Electric road system (ERS) has emerged to deal with drawbacks of electric vehicles. Several solutions are being evaluated at demonstration projects. Until now, ERS is mainly associated with heavy vehicles and the relation to passenger cars is not as clear, where this study explores the social advantages of ERS and passenger cars. A case study is conducted, where an ERS implementation between Helsingborg and Malmö as part of the European route E6 in Sweden is modelled. The NPV with an economic lifespan of 20 years and an interest rate of 3.5 percent amounts to 350 MSEK, considered as high profitable. The CO2 emissions of the studied system would be reduced by 102 000 tonnes CO2, corresponding to a decrease of about 60 percent. Looking at the studied system, heavy trucks are contributing to the most impact. Nevertheless, there is great potential for passenger cars utilising ERS to decrease their emissions and fuel costs. Several semi-structured interviews have been conducted to highlight the prevailing views of ERS and passenger cars and the impact of cost-benefit analysis (CBA) for decision-making of transport investments. Several diverse views of ERS and passenger cars exist. ERS is a large investment, where the main need is among heavy vehicles. However, the profitability would increase as the amount of vehicles utilising ERS increases. In a future road transport system, it is possible that several technologies such as ERS, fast chargers and autonomous vehicles could be utilised simultaneous, and complete each other rather than being substitutes. It is conceivable that ERS is planned out of the needs of heavy vehicles, where passenger cars might benefit of the system as well. More passenger cars would likely utilise ERS as it is implemented to a greater extent. Further, CBA could provide a perception of the investment. However, it does not ensure that the projects are performed or chosen out of highest NPV, since several aspects besides the profitability are considered. Available information of ERS for CBA is yet limited and more data, such as effect relations is needed to facilitate well-founded decisions. In the future, it is likely that CBA of transport investments would become more complex, where several technologies would be considered. The transport sector will most likely alter, and existing assessment methods will presumably be adjusted in line with this. Sverige är ett geografiskt stort och glesbefolkat land med ett stort behov av vägtransporter för såväl privatpersoner som för logistik. Inrikes vägtransport bidrar i stor utsträckning till luftföroreningar, där personbilar står för den största andelen av utsläppen. Den nuvarande minskningstakten av utsläpp är inte tillräcklig för att nå klimatmålen om en fossilfri transportsektor. Elvägar (ERS) har utvecklats för att hantera utmaningar med elfordon. Flera lösningar av teknologin testas vid demonstrationsprojekt och hittills är ERS främst förknippat med tunga fordon. Dock är relationen till personbilar inte lika tydlig, där denna studie undersöker de samhälleliga fördelarna med ERS relaterat till personbilar. En fallstudie har genomförts, där en installation av ERS mellan Helsingborg och Malmö som en del av E6 i Sverige modelleras. Nettonuvärdet med en ekonomisk livslängd på 20 år och en internränta om 3,5 procent uppgår till 350 MSEK, vilket betraktas som hög lönsam. Koldioxidutsläppen från det studerade systemet skulle minskas med 102 000 ton CO2, vilket motsvarar en minskning med drygt 60 procent. Utifrån det studerade systemet bidrar tunga lastbilar till den största inverkan. Likväl finns stor potential för personbilar att nyttja den installerade elvägen för att minska sina utsläpp och bränslekostnader. Flera semistrukturerade intervjuer har genomförts för att lyfta fram de rådande synsätten på ERS och personbilar och effekterna av samhällsekonomiska analyser (CBA) vid beslutsfattande av transportinvesteringar. Det finns flera olika synsätt på ERS relaterat till personbilar. ERS är en stor investering, där det största behovet finns bland tunga fordon. Emellertid ökar lönsamheten med antalet fordon som använder systemet. I ett framtida vägtransportsystem är det möjligt att flera teknologier såsom ERS, snabbladdning av elbilar och autonoma fordon utnyttjas samtidigt och används som komplement istället för att ersätta varandra. Det är tänkbart att ERS planeras och installeras utifrån behoven hos tunga fordon, där även personbilar kan dra fördel av systemet. Dessutom är det sannolikt att fler personbilar skulle utnyttja ERS allteftersom det installeras i större utsträckning. Vidare kan CBA ge en uppfattning om investeringen. Det säkerställer dock inte att projekten genomförs eller väljs utifrån högsta nettonuvärde, eftersom flera aspekter utöver lönsamheten beaktas. Tillgänglig information om ERS för CBA är ännu begränsad och mer data såsom effektsamband behövs för att säkerställa välgrundade beslut. I framtiden är det troligt att CBA av transportinvesteringar blir mer komplexa, där flera tekniker behöver beaktas. Transportsektorn kommer sannolikt att förändras, och befintliga bedömningsmetoder kommer förmodligen att anpassas i linje med detta.

Optimal coordination control for improved power flow of a Smart Grid using smart metering based on genetic algorithm

Scipedia content — Tue, 26 Jan 2021 16:42:29 +0100

The conventional electric power grid has proven inadequate. Because the grid technology currently implemented is outdated, there is manifestation of reliability problems. In this thesis an Intelligent Energy Management System (EMS) for end consumers has been proposed. This system develops an optimal power flow control of a Smart grid using real time measurements in a grid offering energy at invariable price and Genetic Algorithm (GA) for a smart meter which is integrated between distribution grid and end consumers. GA methodology is an evolutionary process, which imitating evolution process of nature. The smart meter determines when to draw the energy from grid or the storage unit for consumption. Furthermore, the EMS provides the ability to end consumers for smart charging in Electric Vehicles (EVs). The first objective of using this algorithm is to reduce the cost for end consumers by charging energy storage unit (ESU) from the grid during the low cost periods. The second objective of this system is to prevent grid overload by shifting the power drawn from high demand period to low demand period. The algorithm use two parameters, the hourly price and the load demand of the grid. It demonstrated that the GA approach is much better in cost saving and grid load reduction compare to conventional grid and fuzzy logic approach. The implementation of GA strategy showed 26.1% cost saving rate in comparison with conventional grid for one year period. In addition, the above strategy is 2.4% better than fuzzy logic approach in cost saving rate.

Το υπάρχον ηλεκτρικό δίκτυο έχει αποδειχθεί ανεπαρκές. Επειδή η τεχνολογία που εφαρμόζεται σήμερα στο δίκτυο είναι ξεπερασμένη, εμφανίζονται προβλήματα αξιοπιστίας. Σ’ αυτή τη διπλωματική εργασία προτείνετε ένα Σύστημα Ευφυούς Ενεργειακής Διαχείρισης για τους καταναλωτές. Αυτό το σύστημα αναπτύσσει έναν βέλτιστο έλεγχο ροής ισχύος ενός έξυπνου δικτύου χρησιμοποιώντας μετρήσεις σε πραγματικό χρόνο σε δίκτυο που προσφέρει ενέργεια σε αμετάβλητη τιμή και το γενετικό αλγόριθμο για ένα έξυπνο μετρητή ο οποίος είναι ενσωματωμένος μεταξύ του δικτύου διανομής και των τελικών καταναλωτών. Η μεθοδολογία ενός γενετικού αλγορίθμου είναι μια εξελικτική διαδικασία, η οποία ουσιαστικά μιμείται την εξέλιξη της φύσης. Ο έξυπνος μετρητής καθορίζει πότε πρέπει να αντληθεί η ενέργεια από το δίκτυο ή την μονάδα αποθήκευσης για κατανάλωση. Επιπλέον, το σύστημα αυτό παρέχει τη δυνατότητα στους καταναλωτές να αποθηκεύουν σε ηλεκτρικά αυτοκίνητα. Ο πρωταρχικός στόχος της χρησιμοποίησης του αλγορίθμου αυτού είναι να μειωθεί το κόστος για τους τελικούς καταναλωτές φορτίζοντας τη μονάδα αποθήκευσης ενέργειας από το δίκτυο κατά τις περιόδους χαμηλού κόστους. Ο δεύτερος στόχος αυτού του συστήματος είναι η αποφυγή της υπερφόρτωσης του δικτύου με τη μετατόπιση ισχύος από περιόδους υψηλής ζήτησης σε περιόδους με χαμηλότερη ζήτηση. Ο αλγόριθμος χρησιμοποιεί δύο παραμέτρους, την ωριαία τιμή και τη ζήτηση φορτίου του δικτύου. Αποδείχθηκε ότι η προσέγγιση του γενετικού αλγορίθμου είναι πολύ καλύτερη όσον αφορά την εξοικονόμηση κόστους και τη μείωση στο φορτίου δικτύου σε σύγκριση με το συμβατικό δίκτυο και την προσέγγιση της ασαφούς λογικής. Η εφαρμογή της στρατηγικής γενετικού αλγορίθμου έδειξε ποσοστό εξοικονόμησης κόστους 26,1% σε σύγκριση με το συμβατικό δίκτυο για περίοδο ενός έτους. Επιπλέον, η πιο πάνω στρατηγική είναι 2,4% καλύτερη από την προσέγγιση της ασαφούς λογικής στο ποσοστό εξοικονόμησης κόστους.

Driven to the Future: Carsickness in Autonomous Vehicles

Scipedia content — Tue, 26 Jan 2021 16:38:26 +0100

Multi-scale multi-domain co-simulation for rapid prototyping of advanced driver assistance systems

Scipedia content — Tue, 26 Jan 2021 16:37:08 +0100

In the last decades, vehicles have evolved from mechanical machines to sophisticated hardware and software (HW/SW) dominated systems. This digital paradigm shift can be explained with the rise of Advanced Driver Assistance Systems (ADAS), as well as applications of highly automated driving. However, such features require a nearly exponential amount of additional SW functionalities. To support the performance demands of such applications, powerful multi and many-processor HW platforms have been employed, exhibiting a trend toward more integrated architectures. Yet, as a consequence, the design and validation, as well as safety assessment of the digital in-vehicle infrastructure of modern cars has become immensely complex.Several techniques arose to bridge this gap, e.g., system engineering strategies, and model-based design and validation methods. In this thesis, it is proposed to augment such traditional approaches with purely simulation-driven techniques to improve and accelerate overall system design. Firstly, the utilization of driving simulators is suggested to conduct virtual road tests in an early application design stage. Furthermore, virtual prototyping is proposed to perform system exploration and extend the simulation scope of ADAS to the embedded HW/SW implementation.However, the main research contributions of the thesis are two techniques that enable efficient full-vehicle modeling. Firstly, multi-scale simulation, an approach to integrate submodels of a top-level simulation system on different design abstractions. Its main benefit is providing a tunable resolution for models, thus enabling a trade-off between the execution performance and the required simulation accuracy. Secondly, multi-domain co-simulation is proposed, a standardized method to interconnect and jointly utilize multiple vehicular simulation ecosystems. This approach addresses the multi-disciplinary nature of vehicles, requiring specialized simulators that are best suited to implement a formalism representing an individual domain.Putting all aforementioned concepts in practice, a comprehensive fully virtual ADAS prototyping ecosystem is presented in this thesis. The proposed framework assembly covers various phases of the ADAS development flow, such as model-based design, virtual system integration, virtual system testing and verification, as well as application refinement. To highlight its potentials, a multitude of ADAS applications are rapidly prototyped via the proposed system. Lastly, insights into application and system-level analyses are presented, while simulation performance evaluation is provided to highlight the acceleration potential of the virtual ecosystems.

Opportunities for short-sea shipping in the Southern African Development Community (SADC) region: evidence based on discrete choice modelling

Scipedia content — Tue, 26 Jan 2021 16:34:03 +0100

The thesis investigates the development of short-sea shipping (SSS) in the Southern African Development Community (SADC) region by studying the determinants of SSS, the stated choice preference of shippers and freight forwarders and the stated intentions of maritime carriers for SSS. It is purported the introduction of SSS in SADC could reduce socio-environmental problems currently faced such as road damage, road congestion, pollution and transport related accidents. Discrete choice modeling (DCM) is employed as the main methodology to study shipper and carrier behavior. Discrete choice modeling permits the construction of general utility functions incorporating various decision maker characteristics and choice attributes to elicit preference of respondents. The general postulate in DCM is that utility is derived from the properties of things rather than the actual thing per se. A particular benefit of DCM in this study is the elicitation of preference for services and interventions that have not been introduced by SSS. The first step in the study is a theoretical investigation of the potential of SSS in the SADC region. It highlights the policy initiatives, the barriers and enablers related to the development of SSS. The proposed SSS system would have three main roles: to offer an alternative mode of freight transport service between port cities, to serve as the main leg in an intermodal transport network, and to serve feeder services between hub-and-spoke ports. The findings reveal that, SSS has the theoretical potential to work in the SADC region, given the large geographic region, projected freight volumes and customs and trade policies the SADC region is pursuing. The second step in the study involves an a-priori study conducted to develop a general understanding of freight transport in SADC. For this purpose, a uniquely developed online survey was conducted across the SADC region to ascertain in particular: who the decision maker is in terms of freight mode choice; and what the significant attributes that influence freight mode choice are. The results reveal that both the shipper and the freight forwarder are involved in mode choice decisions, however the shipper being the dominant decision maker. Furthermore, the results of the exploded logit model reveal that the top five modal attributes that shippers consider most important are: reliability, transport cost, risk of damage, frequency of service and transit time. These results were subsequently employed to inform the shipper and carrier behavior studies. The third step entails the assessment of shipper behavior, where trip specific mode choice decisions are studied along five intra-urban origin-destination (O-D) paired routes (which would form the study corridors). Three of these corridors considered unimodal SSS, and the two considered intermodal SSS. Unimodal SSS was studied along the following corridors: Cape Town (South Africa)~ Walvis Bay (Namibia), Walvis Bay (Namibia) ~ Luanda (Angola) and Durban (South Africa) ~Beira (Mozambique); and intermodal SSS was studied along the following corridors: Durban (South Africa) ~ Harare (Zimbabwe) and Cape Town (South Africa) ~ Windhoek (Namibia). To develop the choice scenarios, d-efficient stated choice experiments were uniquely developed for each of the corridors with the following key modal attributes systematically varied and analyzed across respondents: service frequency, reliability in terms of arriving on time, expected delay, transport cost and transport time. Subsequently, the following choice models were developed: Binary Logit, Mixed Logit and Integrated Choice and Latent Variable Structure models for the unimodal corridors; and Multinomial Logit, Nested Logit and Cross Nested Logit models for the intermodal corridors. The results highlight that in addition to the modal attributes, mode choice decisions are driven by shipper characteristics and situational characteristics. Moreover, the unimodal SSS study reveals that underlying latent perceptions also influence freight mode choice decisions; while the intermodal SSS study reveal strong correlations in the intermodal SSS alternatives, which requires improved intermodal capability if SSS is to become competitive. The fourth step in the study entail the assessment of maritime carriers preference for SSS given varying levels of maritime conditions that include: dedicated freight volumes, income from freight, port dues discount, terminal handling fees discount and ship registration requirements. The results of an ordered logit model reveal that ship registration provisions and terminal handling charges are the most important to the development of SSS from a carrier side. Moreover, ship registration and maritime cabotage provisions require visitation to boost the participation of carriers in SSS. The last step of the study revisits the modeling results and considers their implications through the estimation of willingness-to-pay and attribute elasticities. The results were then employed to suggest policy actions and interventions to develop SSS.

An evaluation of Rea Vaya and Gautrain, its potentials and impacts on spatial and transportation planning in the City of Johannesburg

Scipedia content — Tue, 26 Jan 2021 16:32:29 +0100

MSc (Urban and Regional Planning), North-West University, Potchefstroom Campus The unique urban contexts that emanated from the apartheid history of South Africa informed the transport landscape of the City of Johannesburg. Apartheid‘s divisive spatial planning and land use management policies promoted sprawling and separated labour from work. This was further exacerbated by poor funding of public transport and road designs that encouraged the use of private cars. The democratization of the country in 1994 was the beginning of a new phase in the history of the city. A new approach to policy formulations that entails the provision of public transport as one of the tools to end years of marginalization and inequalities was adopted by the national government. It soon became a policy direction that reflects in planning decisions of all spheres of government. The Rea Vaya BRT and the Gautrain were respectively introduced by the municipal and provincial governments to demonstrate governments‘ commitments to the new policy direction. While the Gautrain was implemented to facilitate elite movement within Gauteng and to crowd investments and economic growths around station nodes; the BRT was provided for marginalized commuters in Soweto, to provide a sustainable alternative to the dominant minibus taxi. Although the two modes (Rea Vaya and Gautrain) have endured almost a decade filled with public sentiments and other issues, this research concludes that most of the challenges are associated with the country‘s historical context and the age of these transport systems. The Gautrain has demonstrated that viable alternatives to the private car can be provided, with its satisfactory feedbacks from users; and some of its station nodes (Sandton, Rosebank and Pretoria) have showed promises of transit-oriented development, one of the project‘s key objectives. The other stations have been unable to stimulate growth due to reasons like non-implementation of their Urban Design Frameworks and lack of public sector investment required to attract private investors. The Rea Vaya, in its third phase of implementation, has been extended further north to Sandton in spite of both its inability to induce modal change and its low ridership figures. The research identifies factors like low peak to base ratio, pricing and the city‘s disjointed urban fabric as some of the reasons for its below average performance. By drawing from the highlights and limitations, the study recommends that public transport provision should be institutionally integrated across and within spheres of government. Similarly, harmonization of the funding structure, better understanding of users‘ needs and travel patterns, underlined with continuity of policy direction and objectives will equally help to achieve optimum outputs. Master

The reverse logistics of electric vehicle batteries : Challenges encountered by 3PLs and recyclers

Scipedia content — Tue, 26 Jan 2021 16:26:21 +0100

Background: The growing number of electric vehicles gives rise to a whole new reverse supply chain. Once the electric vehicle batteries reach their end-of-life, societal and governmental pressure forces automotive manufacturers to set up a network for disposing the hazardous batteries. Although, the volumes of returned batteries remain low, volumes will increase in upcoming years. Current networks and processes related to the return flow of electric vehicle batteries are not well established, nor well defined. Thus, creating an urgency to develop efficient collection networks. Purpose: The purpose of this study is to investigate how reverse logistics networks are currently set up and to provide an overview of how the different actors and processes are connected. In addition, this thesis aims to identify challenges encountered by logistics providers and recyclers. By doing so, we hope to contribute to the research gap of which factors that constitutes a bottleneck for further development of the reverse logistics chain of electric vehicle batteries. Method: The thesis conducts an interview study and is qualitative in nature. Semi-structured interviews generated empirical data, which was analysed through cross-case analysis incorporating a thematic analysis. Through this analysis we were able to achieve new theoretical understandings in connection to institutional theory. Conclusion: Through empirical findings a detailed framework of the reverse logistics chain of EVBs is portrayed. Furthermore, different challenges span over the processes illustrated in the framework. This presents an overview which is not found in current literature and extends current research on this topic.

The Role of Psychological Capital in Perception of Safety Climate Among Air Traffic Controllers

Scipedia content — Tue, 26 Jan 2021 16:23:13 +0100

Over recent decades, research on antecedents of safety in High Reliability Organizations (HROs) has shifted from focusing mostly on technical issues to placing greater emphasis on human factors. Although an abundance of research suggests that human factors seem to play an important part in most accidents and near misses, there is still a shortage of research on the underlying mechanisms and processes involved in unsafe acts and safety critical behavior. Thus, many research questions regarding the impact of human factors still remain relatively unexplored. The fairly new direction of Positive Organizational Behavior (POB) has presented a fertile theoretical and methodological foundation for examining safety issues in HROs. One promising new POB perspective is Psychological Capital (PsyCap), a higher order construct that consists of the sub-dimensions: efficacy, hope, optimism, and resiliency. The overall aim of this thesis is to investigate the relationship between PsyCap and safety in HROs."/p" "p"The current study examines diverse empirical evidence to assess whether PsyCap could represent a potential antecedent to psychological safety climate and loss prevention across three different HROs (i.e., the aviation, shipping and offshore oil and gas industries). More specifically, possible mediators (i.e., positive/negative emotions and job satisfaction) and possible moderators (i.e., work role) of this relationship were examined in Papers 1 and 2. The influence of impression management and self-deception is controlled for in Paper 2, while the potential buffering effect of PsyCap on the relationship between worries about workplace risks and sleepiness is examined in Paper 3."/p" "p"The first study examined whether PsyCap is related to individual perceptions of safety climate in Air Traffic Control (ATC). The results from an all-Norwegian sample of about 25% of the population of Norwegian air traffic controllers showed that PsyCap was positively correlated with and explained almost 1/3 of the variance in perceived safety climate. In the second part of the study, the mediating effects of positive and negative emotions were controlled for, to see whether the respondents were “wearing rose tinted glasses” and answered the questions in an overly positive way. The results showed that neither positive nor negative emotions mediated the relationship between PsyCap and safety climate."/p" "p"The aim of the second study was to replicate and extend the findings from the ATC study in a new sample from a different type of HRO. Thus, the second study was conducted among maritime workers of different nationalities working for three Norwegian shipping companies. Again, the results showed that PsyCap was positively related to perceptions of safety climate. PsyCap contributed to the variance in perceived safety climate, even after adjusting for socially desirable responding. Officers with high scores on PsyCap were found to have a more positive perception of the safety climate than the non-officers with high PsyCap scores. In the second part of the study, a positive relation between perceived safety climate and job satisfaction was established, as well as between PsyCap and job satisfaction. A crossnational difference was discovered in the sample. An indirect effect of PsyCap with perceived safety climate through job satisfaction was valid only for European workers and not for Filipinos. Altogether, PsyCap and job satisfaction explained more than 20% of the variance in perceived safety climate."/p" "p"The third study shed light on PsyCap as a protective factor in a safety critical work environment. The relationship between worries about accidents and sleepiness was examined in a sample of offshore workers from different nationalities, in order to investigate whether PsyCap could represent a protective factor. The findings indicated a reverse buffering effect in that PsyCap only had a protective impact on sleepiness when worries about accidents were low. The established associations remained consistent after controlling for workers’ years of experience as seafarers and their ratings of perceived safety climate."/p" "p"In conclusion, this thesis extends the previous research by investigating the role of POB in safety. More precisely, it establishes empirical evidence suggesting that the behavioral dispositions of PsyCap are related to perceived safety climate across HROs from the aviation, offshore, and shipping industries. Thus, an increased emphasis on POB may present a new approach to increasing safety focus and loss prevention in these organizations. Future research should also investigate other HROs. Including PsyCap in the safety research could help create a better understanding of how people make work decisions based on their outlook on work and life in general. Although these results seem promising, more research is still needed, and this dissertation also addresses future research needs and the potential practical implications of these findings. Hopefully, there will be more research on PsyCap and safety aimed at preventing accidents in HROs.

Potential of V2G in a Rural Low-Voltage Grid on Gotland for Voltage and Power Capacity Control

Scipedia content — Tue, 26 Jan 2021 16:19:58 +0100

The Swedish transportation sector needs to undergo major changes in order to achieve the established goals for climate and environment. The largest change is the replacement of fossil-fuelled vehicles to vehicles propelled by renewable energy sources, such as biofuels and electricity. To account for an increase in local electric power consumption, the electric power infrastructure of Sweden needs to adapt through expansion and reconstruction of the electric power grid. However, changes in infrastructure are usually expensive. It is therefore suitable to also examine alternative solutions, which could potentially be more cost efficient. One of these solutions are vehicle-to-grid (V2G), where electric vehicles acts as local electric power control and provides auxiliary services to the electric power grid. This thesis is a case study of a part of a low-voltage electric power grid on Gotland, with the goal of analysing the potential of V2G in the investigated area. The study focused on utilizing V2G for balancing electric power consumption and generation, and for adjusting voltage levels. Simulations of the area were executed in PSS®E for three different cases; one high-load case, low-load case and average-load case. It was found that by utilizing V2G a ramp up of electric power during mornings was delayed by approximately one hour, making the electric power grid potentially more compatible with photovoltaics (PV). However, the overall effects from V2G was fairly low. This outcome can partly be explained by the assumptions made in the report, and also due to some odd behaviour of the system model.

Deep reinforcement learning for the optimization of traffic light control with real-time data

Scipedia content — Tue, 26 Jan 2021 16:19:24 +0100

Treball fi de màster de: Master's Degree in Data Science Directors: Hrvoje Stojic, Anestis Papanikolaou In this thesis we develop a traffic light control agent that can manage traffic lights with the objective to reduce traffic jams, trip time and other traffic metrics in a given network using reinforcement learning. To this end, we implement a Double Deep Q-Network algorithm and test its performance in controlling traffic lights on a ’small’ and a ’large’ traffic junction. We find that this algorithm beats a fixed traffic light phase program when traffic demand fluctuates, as it is capable of reacting to real-time traffic situations. The algorithm can be scaled up and holds promise to also perform well in controlling larger transport networks. En aquest treball de final de màster es desenvolupa un algorisme d'aprenentatge reforçat pel control de semàfors amb l'objectiu de reduir temps de trajecte i retencions. Específicament, s'ha implementat l'algorisme Double Deep Q-Network i s'ha comprovat la seva eficàcia comparant-lo amb escenaris realistes de control d'una intersecció simple i d'una complexa. S'ha demostrat que aquest algorisme es comporta millor que l'escenari real en el qual el canvi de fase es duu a terme amb intervals de temps fixes. Els resultats indiquen que aquesta tècnica és capaç d'adaptar-se a les situacions de trànsit canviants i per tant obtenir millor resultats que l'escenari real. L'algorisme pot ser adaptat per controlar xarxes de trànsit més grans.

Model for determining resilience in transport systems: an application in the air traffic system.

Scipedia content — Tue, 26 Jan 2021 16:17:18 +0100

Este trabalho propõe um modelo de análise quantitativa baseado em simulação de eventos discretos para a determinação do nível de resiliência em sistemas de transporte. O nível de resiliência é avaliado considerando as funções de desempenho relacionadas a capacidade, ao nível de serviço e ao tempo de recuperação do sistema de transporte frente a um evento de ruptura. O modelo é validado através de estudo de caso aplicado ao sistema de tráfego aéreo brasileiro, considerando um espaço aéreo composto por 12 setores de uma região de informação de voo (FIR), suas demandas diárias de aeronaves, sua malha de rotas aéreas e sua rede de aeródromos instalada. O evento de ruptura é oriundo de condições meteorológicas adversas que afetam simultaneamente as operações de pouso e decolagem no aeroporto do Rio de Janeiro - Santos Dumont (SBRJ) e no aeroporto de São Paulo - Congonhas (SBSP). Conclui-se que o modelo de análise permite a plena determinação do nível de resiliência em sistemas de transportes, mesmo em situações de rupturas operacionais simultâneas. This work proposes a quantitative analysis model based on discrete event simulation (DES) to determine the resilience level of transport systems. The resilience level is evaluated considering the performance functions related to capacity, service level and recovery time of the transport system in a presence of disruptive events. The model is validated through a case study applied to the Brazilian air traffic system, considering an airspace with 12 sectors of a flight information region (FIR), its daily aircraft demands, its air route network and its aerodromes network installed. The disruptive event comes from adverse weather conditions that simultaneously affect the landing and takeoff operations at Rio de Janeiro - Santos Dumont (SBRJ) and São Paulo - Congonhas (SBSP) airports. It is concluded that the analysis model allows the full determination of the resilience level in transport systems, even in situations of simultaneous operational disruptions.

Enriching the internet control-plane for improved traffic engineering

Scipedia content — Tue, 26 Jan 2021 16:14:02 +0100

One of the major challenges in the evolution of the Internet architecture is the definition of a protocol architecture that allows to solve the following major issues in Internet routing and traffic forwarding capabilities, (i) keeping a routing state that is manageable with current and forthcoming computing infrastructure – i.e., with few millions of states, (ii) offering a scalable pull architecture in support of data-plane programmability, (iii) offering a scalable forwarding plane able to be regularly optimized with only active flows information, (iv) offering locator/identifier separation for advanced IP mobility, (v) is incrementally deployable, (vi) can enhance the support of over-the-top services. The Locator/Identifier Separation Protocol (LISP) has been identified as one of the rising protocols in this respect. In its current status, it supports the above mentioned requirements at a level that is acceptable for basic networking environments. However, it shows too limited capacities when it comes to take into consideration fault resiliency and capability to react fast to network state updates. These shortcomings can be compensated by enhancing the control-plane architecture, and the routing algorithms therein. In this dissertation, we propose new protocol features and experiment novel control-plane primitives, as well as hybrid distributed-centralized routing state dissemination algorithms, to scale with different network conditions. We first design and build own open source LISP data-plane and control plane node, comparing it with other implementations, showing how our implementation can scale for large networks and reach performances suitable for real deployments. We present how our implementation served to operate all network nodes (data-plane and control-plane nodes) of a large scale experimentation testbed, the LISP-Lab testbed. Then we propose a novel LISP-based solution for VM live migrations across geographically separated datacenters over wide area IP networks. Experimenting it at large scale, we show that with our approach we can easily reach sub-second downtimes upon Internet-wide migration, even for very distant clients. Moreover, we investigate cross-layer network optimization protocols, in particular in relation with the Multipath Transport Control Protocol (MPTCP) to which LISP can deliver path diversity in support of bandwidth increase, confidentiality support and connection reliability, also using LISP traffic engineering network overlays. Despite we could benefit from only few overlay network nodes, we could experimentally evaluate our proposals showing the positive impact by using our solution, the negative impact of long round-trip times on some MPTCP subflows, and the strong correlation between the differential round-trip time among subflows and the throughput performance. Finally, we worked on a framework to improve LISP operation at the Internet scale, by facilitating cooperation between LISP Mapping Systems and introducing more automation in the LISP connectivity service delivery procedure. We believe such optimization could raise awareness among the service providers’ community, yielding new business opportunities related to LISP mapping services and the enforcement of advanced inter-domain traffic engineering policies for the sake of better quality of service guarantees.; L'un des défis majeurs de l'évolution de l'architecture Internet est la définition d'une architecture protocolaire permettant d'améliorer le routage, et en particulier (i) conserver un système de routage gérable avec les technologies actuelles et futures c'est-à-dire, avec quelques millions d'états, (ii) offrir une architecture apte à faciliter la programmabilité du plan de transfert, (iii) proposer un système de routage évolutif pouvant être régulièrement optimisé avec uniquement les informations sur les flux actifs, (iv) fournir une séparation entre localisateurs et identificateurs pour la mobilité IP avancée, (v) faciliter un déploiement incrémental, (vi) mieux servir les services applicatifs "over-the-top". Le protocole LISP (\\textit{Locator/Identifier Separation Protocol}) a été identifié comme l'un des protocoles émergents à cet égard. Dans son état actuel, il répond très bien aux besoins susmentionnés. Cependant, il subit des limitations lorsqu'il s'agit de prendre en compte la résilience et la capacité à réagir rapidement aux mises à jour de l'état du réseau. Ces inconvénients peuvent être compensés en améliorant l'architecture du plan de contrôle et ses algorithmes de routage. Dans cette thèse, nous proposons une nouvelle architecture réseau-système et expérimentons de nouvelles primitives de plan de contrôle, ainsi que d'algorithmes de diffusion des états, en testant son passage à l'échelle avec différentes conditions de réseau. Nous concevons et construisons d'abord un nœud de plan de données et de plan de contrôle LISP open source. Nous le comparons avec d'autres implémentations en montrant que notre implémentation atteint des performances adaptées aux vrais déploiements. Nous montrons comment notre implémentation a permis la mise en oeuvre d'une plateforme d'expérimentation à grande échelle, la plate-forme LISP-Lab, en opération aussi bien les fonctions de plan de transfert que les fonctions de plan de contrôle. En suite, nous proposons une nouvelle solution pour les migrations à chaud de machines virtuelles à travers des centres de données géographiquement répartis sur des réseaux IP étendus. Des tests dans un testbed réel connecté nativement à Internet montrent qu'avec notre approche, nous pouvons facilement atteindre des temps d'arrêt inférieurs à la seconde lors de la migration sur une grande échelle, même pour des clients très distants. En outre, nous avons étudié des protocoles d'optimisation de réseau multicouche, en particulier en relation avec le protocole MPTCP (Multipath Transport Control Protocol), auquel LISP peut offrir une diversité de chemins pour l’agrégation de bande passante, ainsi qu’une plus grande confidentialité et fiabilité des connexions. Bien que nous ne puissions bénéficier que de quelques nœuds de réseau superposés, nous avons pu évaluer expérimentalement nos propositions en montrant l'impact positif de notre solution, l'impact négatif des longs temps d'aller-rétour sur certains sous-flux MPTCP, et la forte corrélation entre le temps d'aller-retour différentiel et le débit. Enfin, nous avons travaillé sur une refonte du plan de contrôle de LISP afin d’améliorer son fonctionnement du à l'échelle d’Internet, en facilitant la coopération entre les systèmes de mapping LISP et en introduisant plus d'automatisation dans la procédure de fourniture de services de connectivité LISP. Nous croyons qu'une telle optimisation pourrait sensibiliser la communauté des fournisseurs de services, générant de nouvelles opportunités commerciales liées aux services de cartographie LISP et l'application de politiques d'ingénierie de trafic interdomaines avancées dans le but d'obtenir de meilleures garanties de qualité de service.

Integration of electric vehicles in a flexible electricity demand side management framework

Scipedia content — Tue, 26 Jan 2021 16:07:06 +0100

Recent years have seen a growing tendency that a large number of generators are connected to the electricity distribution networks, including renewables such as solar photovoltaics, wind turbines and biomass-fired power plants. Meanwhile, on the demand side, there are also some new types of electric loads being connected at increasing rates, with the most important of them being the electric vehicles (EVs). Uncertainties both from generation and consumption of electricity mentioned above are thereby being introduced, making the management of the system more challenging. With the proportion of electric vehicle ownership rapidly increasing, uncontrolled charging of large populations may bring about power system issues such as increased peak demand and voltage variations, while at the same time the cost of electricity generation, as well as the resulting Greenhouse Gases (GHG) emissions, will also rise. The work reported in this PhD Thesis aims to provide solutions to the three significant challenges related to EV integration, namely voltage regulation, generation cost minimisation and GHG emissions reduction. A novel, high-resolution, bottom-up probabilistic EV charging demand model was developed, that uses data from the UK Time Use Survey and the National Travel Survey to synthesise realistic EV charging time series based on user activity patterns. Coupled with manufacturers’ data for representative EV models, the developed probabilistic model converts single user activity profiles into electrical demand, which can then be aggregated to simulate larger numbers at a neighbourhood, city or regional level. The EV charging demand model has been integrated into a domestic electrical demand model previously developed by researchers in our group at the University of Edinburgh. The integrated model is used to show how demand management can be used to assist voltage regulation in the distribution system. The node voltage sensitivity method is used to optimise the planning of EV charging based on the influence that every EV charger has on the network depending on their point of connection. The model and the charging strategy were tested on a realistic “highly urban” low voltage network and the results obtained show that voltage fluctuation due to the high percentage of EV ownership (and charging) can be significantly and maintained within the statutory range during a full 24-hour cycle of operation. The developed model is also used to assess the generation cost as well as the environmental impact, in terms of GHG emissions, as a result of EV charging, and an optimisation algorithm has been developed that in combination with domestic demand management, minimises the incurred costs and GHG emissions. The obtained results indicate that although the increased population of EVs in distribution networks will stress the system and have adverse economic and environmental effects, these may be minimised with careful off-line planning.

Driven to the Future

Scipedia content — Tue, 26 Jan 2021 16:04:42 +0100

Critical evaluation of smart mobility policies of Konya metropolitan municipality

Scipedia content — Tue, 26 Jan 2021 15:57:06 +0100

population in urban areas increases and problems arise as a consequence, many cities turn to smart city transformation. Some scholars argue that smart cities can provide strong solutions to urban problems. Smart city discourse mainly touches upon six major concepts which cities are required to apply to become a smart city: Smart economy, smart people, smart governance, smart environment, smart living and finally smart mobility based on ICT. The most common issues based upon increasing population is transportation problems which has been seen in Turkish cities as well. As a response to these, smart mobility applications are becoming more and more widespread in Turkish urban areas. The purpose of this study is to provide a critical evaluation of transformation of Konya Metropolitan Area through smart mobility tools. Konya Metropolitan Area is becoming heavily car dependent and majority of the smart mobility applications target vehicles. Additionally, some recent policies and actions of the metropolitan municipality focus on public transportation. This study aims to evaluate smart mobility actions and policies in Konya Metropolitan area and to understand how smart mobility has become a main focal point of transportation policies in the city. The research benefits from interviews with Municipal officials as well as official documents such as plans, projects and their associated reports. Finally, the study concludes with some policy recommendations to push smart mobility agenda forward in Konya Metropolitan Area. Thesis (M.S.) -- Graduate School of Social Sciences. Urban Policy Planning and Local Governments.

Development of Aircraft Wake Vortex Dynamic Separations Using Computer Simulation and Modeling

Scipedia content — Tue, 26 Jan 2021 15:55:02 +0100

This dissertation presents a research effort to evaluate wake vortex mitigation procedures and technologies in order to decrease aircraft separations, which could result in a runway capacity increase. Aircraft separation is a major obstacle to increasing the operational efficiency of the final approach segment and the runway. An aircraft in motion creates an invisible movement of air called wake turbulence, which has been shown to be dangerous to aircraft that encounter it. To avoid this danger, aircraft separations were developed in the 1970s, that allows time for wake to be dissipated and displaced from an aircraft's path. Though wake vortex separations have been revised, they remain overly conservative. This research identified 16 concepts and 3 sub-concepts for wake mitigation from the literature. The dissertation describes each concept along with its associated benefits and drawbacks. All concepts are grouped, based on common dependencies required for implementation, into four categories: airport fleet dependent, parallel runway dependent, single runway dependent, and aircraft or environmental condition dependent. Dynamic wake vortex mitigation was the concept chosen for further development because of its potential to provide capacity benefit in the near term and because it is initiated by air traffic control, not the pilot. Dynamic wake vortex mitigation discretizes current wake vortex aircraft groups by analyzing characteristics for each individual pair of leader and follower aircraft as well as the environment where the aircraft travel. This results in reduced aircraft separations from current static separation standards. Monte Carlo simulations that calculate the dynamic wake vortex separation required for a follower aircraft were performed by using the National Aeronautics and Space Administration (NASA) Aircraft Vortex Spacing System (AVOSS) Prediction Algorithm (APA) model, a semi-empirical wake vortex behavior model that predicts wake vortex decay as a function of atmospheric turbulence and stratification. Maximum circulation capacities were calculated based on the Federal Aviation Administration's (FAA) proposed wake recategorization phase II (RECAT II) 123 x 123 matrix of wake vortex separations. This research identified environmental turbulence and aircraft weight as the parameters with the greatest influence on wake vortex circulation strength. Wind has the greatest influence on wake vortex lateral behavior, and aircraft mass, environmental turbulence, and wind have the greatest influence on wake vortex vertical position. The research simulated RECAT II and RECAT III dynamic wake separations for Chicago O'Hare International (ORD), Denver International Airport (DEN) and LaGuardia Airport (LGA). The simulation accounted for real-world conditions of aircraft operations during arrival and departure: static and dynamic wake vortex separations, aircraft fleet mix, runway occupancy times, aircraft approach speeds, aircraft wake vortex circulation capacity, environmental conditions, and operational error buffers. Airport data considered for this analysis were based on Airport Surface Detection Equipment Model X (ASDE-X) data records at ORD during a 10-month period in the year 2016, a 3-month period at DEN, and a 4-month period at LGA. Results indicate that further reducing wake vortex separation distances from the FAA's proposed RECAT II static matrix, of 2 nm and less, shifts the operational bottleneck from the final approach segment to the runway. Consequently, given current values of aircraft runway occupancy time under some conditions, the airport runway becomes the limiting factor for inter-arrival separations. One of the major constraints of dynamic wake vortex separation at airports is its dependence on real-time or near-real-time data collection and broadcasting technologies. These technologies would need to measure and report temperature, environmental turbulence, wind speed, air humidity, air density, and aircraft weight, altitude, and speed. PHD

The Cantareira Tramway and its relation with local development: urban infrastructure and passenger transport (1893-1965)

Scipedia content — Tue, 26 Jan 2021 15:42:21 +0100

Esse trabalho analisa a trajetória do Tramway da Cantareira em sua relação com o desenvolvimento das regiões atendidas por seus ramais, notadamente a zona norte do município de São Paulo e Guarulhos, tendo como recorte temporal os anos de 1893 a 1965, período de funcionamento dessa linha férrea. Para isso, além da bibliografia pertinente acerca do assunto, utiliza como fonte de pesquisa amplo conjunto documental de cunho arquivístico e, de forma complementar, periódicos que circulavam na época. Subdividida em quatro capítulos, esta tese analisa inicialmente a crise de gestão dos recursos hídricos na capital de São Paulo na segunda metade do século XIX com vistas a compreender as razões de o governo estadual ter iniciado a construção do Tramway da Cantareira. Em seguida, estuda os primeiros anos de funcionamento da ferrovia, momento no qual ela presta importante contribuição nas obras de infraestrutura da capital, com destaque para aquelas relacionadas ao abastecimento de água e saneamento básico. Uma vez analisada a história de seus anos iniciais, o trabalho busca compreender a percepção que a população, a imprensa e o governo tinham em relação aos seus serviços, examinando os projetos que previam desde o seu arrendamento à iniciativa privada até a sua extensão para além dos municípios de São Paulo e Guarulhos, em uma fase na qual o transporte de passageiros já se tornava a sua principal atividade. Por fim, examina o processo de anexação dessa linha férrea à Estrada de Ferro Sorocabana até o momento de sua desativação, em 1965. This study analyzes the trajectory of the Cantareira Tramway in its relation with the development of the regions served by its branches, notably the northern part of the municipality of São Paulo and Guarulhos, focusing in the years from 1893 to 1965, period of operation of the railroad. To this end, besides the pertinent bibliography on the subject, this study uses as a research source a large set of archival documents complemented by periodicals circulating at the time. Subdivided into four chapters, this thesis initially analyzes the crisis of water resources management in the capital of São Paulo in the second half of the 19th century, in order to understand the reasons why the state government started the construction of the Cantareira Tramway. Subsequently, it studies the first years of the railway operation, when it makes an important contribution to the infrastructure works of the capital, especially those related to water supply and basic sanitation. Once the history of its initial years is analyzed, this study tries to understand the perception that the population, the press and the government had concerning the Cantareira Tramway services, examining the projects it predicted from its lease to the private sector until its extension beyond the municipalities of São Paulo and Guarulhos, in a period where transportation of passengers was already its main activity. Finally, it examines the annexation process of this railway to the Sorocabana Railroad until it was decommissioned in 1965.

Digital divide from the perspective of smart mobility applications

Scipedia content — Tue, 26 Jan 2021 15:41:08 +0100

Digital divide concept has been drawing attention in the world since the first appearance of the internet. It explains the inequality between people caused by their ability to access any technology and interpret this technology to be able to use it. The concept emerged as a consequence of technology diffusion, and related information and communication technologies that came into people's life. Since there is a huge population living in different countries and cities who is affecting from digital divide, it become a multi-dimensional complex phenomenon which have different types and dimension. The increasing role of smart phones in daily life triggered mobile apps to become one of the most popular ICT-based services and the process of using public transport is intended to be supported and eased by mobile applications in smart phones. However, whether these services are able to be accessed and used by every person in population is rather unclear. The case study conducted in the thesis analyzes this ability to access and use of the mobile public transport applications. In this context, digital divide is approached from two different perspectives; the types and the dimensions. As a case, METU campus were selected in the frame of mobile public transport applications of Ankara, to investigate the validity of access and social digital divide, and the effect of income, education level, occupation, age and gender on digital divide. Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. City and Regional Planning.

Control of vehicle platoons and traffic dynamics : catch-up coordination and congestion dissipation

Scipedia content — Tue, 26 Jan 2021 15:34:22 +0100

Traffic congestion is a constantly growing problem, with a wide array ofnegative effects on the society, from wasted time and productivity to elevated air pollution and increased number of accidents. Classical traffic control methods have long been successfully employed to alleviate congestion, improving the traffic situation of many cities and highways. However, traffic control is not universally employed, because of the necessity of installing additional equipment and instating new legislation. The introduction of connected, autonomous vehicles offers new opportunities for sensing and controlling the traffic. The data that most of the vehicles nowadays provide are already widely used to measure the traffic conditions. It is natural to consider how vehicles could also be used as actuators, driving them in a specific way so that they affect the traffic positively. However, many of the currently considered strategies for congestion reduction using autonomous vehicles rely on having a high penetration rate, which is not likely to be the case in the near future. This raises the question: How can we influence the overall traffic by using only a small portion of vehicles that we have direct control over? There are two problems in particular that this thesis considers, congestion wave dissipation and avoidance, and platoon catch-up coordination. First, we study how to dissipate congestion waves by use of a directly controlled vehicle acting as a moving bottleneck. Traffic data can help predict disturbances and constraints that the vehicle will face, and the individual vehicles can be actuated to improve the overall traffic situation. We extend the classical cell transmission model to include the influence of a moving bottleneck, and then use this model to devise a control strategy for an actuator vehicle. By employing such control, we are able to homogenize the traffic without significantly reducing throughput. Under realistic conditions, it is shown that the average total variation of traffic density can be reduced over 5%, while the total travel time increases only 1%. Second, we study how to predict and control vehicles catching up in order to form a platoon, while driving in highway traffic. The influences of road grade and background traffic are examined and vehicles attempting to form a platoon are modelled as moving bottlenecks. Using this model, we are able to predict how much the vehicles might be delayed because of congestion and adjust the plan accordingly, calculating the optimal platoon catch-up speeds for the vehicles by minimizing their energy consumption. This leads to a reduction of energy cost of up to 0.5% compared to the case when we ignore the traffic conditions. More importantly, we are able to predict when attemptingto form a platoon will result in no energy savings, with approximately 80% accuracy. Trafikstockning är ett ständigt växande problem, med ett brett utbud av negativa effekter på samhället, från bortkastad tid och produktivitet till ökade mängd luftföroreningar och antal olyckor. Klassiska metoder för trafik kontroll har länge använts framgångsrikt för att lindra detta problem, med förbättrad trafiksituation för många städer och motorvägar. Trafik kontrollen är emellertid inte universellt tillämpad eftersom den är beroende av ytterligare utrustning och ny lagstiftning som behover instaleras och införas. Införandet av uppkopplade, autonoma fordon medför nya möjligheter att mäta och kontrollera trafiken. Data som de flesta fordon tillhandahållar redan idag används allmänt för att mäta trafikförhållandena. Det är naturligt att överväga hur fordon också skulle kunna användas som ställdon, genom att driva dem på ett visst sätt så att de påverkar trafiken positivt. Men många av dagens strategierna för trängselnedsättning med hjälp av autonoma fordon är beroende av att de tillämpas av en stor del av fordonen, vilket sannoliktinte kommer att bli fallet inom en snar framtid. Det väcker frågan: Hur kan vi påverka den totala trafiksituationen genom att kontrollera en liten del avfordonen? Det finns två problem specifika problem som den här avhandlingentar hänsyn till, trängselvågsavledning och –undvikande samt koordinering av fordonståg av lastbilar. I det första problemet studerar vi hur vi kan skingra trängselvågor med hjälp av ett direktstyrt fordon som fungerar som en rörlig flaskhals. Trafikdatakan hjälpa till att förutsäga störningar och begränsningar som fordonet kommer att stöta på, och de enskilda fordonen kan styras för att förbättra den totala trafiksituation. Vi utvidgar den klassiska cellöverföringsmodellenför att inkludera påverkan av en rörlig flaskhals och använder sedan denna modell för att utforma en kontrollstrategi för ett styrbart fordon. Genom att använda sådan styrning kan vi homogenisera trafiken utan att avsevärt minska genomströmningen. Under realistiska förhållanden visar vi att den genomsnittliga totala variationen i trafiktäthet kan minskas med över 5%, medan den totala körtiden ökar med endast 1%. I det andra problemet studerar vi hur vi kan förutsäga och styra fordonens hastighetsprofiler vid formering av fordonståg under körning i motorvägstrafik. Påverkan av väglutning och motorvägstrafik undersöks, och fordon som försöker bilda en fordonståg modelleras som rörliga flaskhalsar. Med denna modell kan vi förutsäga förseningar på grund av trängsel och justera planen i enlighet med dessa, samt beräkna de optimala hastigheterna för fordonengenom att minimera energiförbrukningen. Detta leder till en minskning av energikostnaden på upp till 0,5% i jämförelse med fallet när vi ignorerar trafikförhållandena. Ännu viktigare är att vi kan vi förutsäga när försök att bildaett fordonståg kommer att resultera i utebliven energibesparing, med ungefär 80% noggrannhet. "p"QC 20181212"/p""p"The research leading to these results has received fundingfrom the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 674875, VINNOVA within the FFI program under contract 2014-06200, the Swedish Research Council, the Swedish Foundation for Strategic Research and Knut and Alice Wallenberg Foundation. The author is affiliated with the Wallenberg AI, Autonomous Systems and Software Program (WASP).

Measuring and Analyzing Accessibility to Green-Blue Areas and Public Transportation : A study of Stockholm’s progress in achieving the United Nations Agenda 2030’s SDG 11

Scipedia content — Tue, 26 Jan 2021 15:32:11 +0100

The rapid urbanization of populations from rural areas to cities calls for more sustainable focused urban planning to combat the negative effects of urban sprawl. The United Nations’ Agenda 2030 includes the 17 Sustainable Development Goals (SDGs) and 169 targets that aim to unite both developed and developing countries in transforming humanity and the planet for a more sustainable future. One of these goals is SDG 11, making cities and human settlements inclusive, safe, resilient and sustainable. A large part in achieving the targets of SDG 11 is measuring the current access urban residents have to things such as public green-blue spaces as well as public transportation. This thesis will aim to study Stockholm’s achievement of SDG 11 sub-targets 11.2 and 11.7 of Agenda 2030. In order to meet this aim, the following objectives will be pursued. The first objective is to study the degree to which Stockholm County currently has universal access to green-blue areas and public transportation by conducting a GIS-based analysis. The second objective is to improve our understanding of the socio-economic status of residents who have and do not have accessibility to green-blue areas and public transportation by statistically analyzing correlations between environmental and socio-economic indicators. The methodology included qualitative methodologies such as a literature review, interviews and collaborative focus group meetings with Södertörnsanalysen as well as quantitative methodologies such as spatial analysis and statistical analysis. The results show that while Stockholm has impressively high accessibility for its residents, it has yet to meet Agenda 2030 SDG 11targets 11.2 and 11.7 because the accessibility was not universal. The results also found that people with lower income, people who own their flats/homes and people with children have higher accessibility to green areas. It was also shown that people with higher income, people who rent their flats/homes and have no children have higher access to public transportation.This result can be expected as the bulk of people with higher incomes are living in the innercity where they have high access to urban services and rail stops, but not necessarily green areas. It is important to state that at 300 m from residencies, both access to green areas and access to public transportation is almost 100%. At 500 m from residencies, access to blueareas is close to 35 %, which is not almost complete, but still a high percentage since access to blue areas is a bit of a luxury. This thesis ultimately demonstrates the importance of understanding environmental and socio-economic indicators in urban planning especially if the goals of Agenda 2030 are to be met. This thesis also took steps towards building a methodology for quantifying accessibility and it is recognized that further studies can be conducted to further contribute to sustainable urban planning and development. Den snabba urbaniseringen där människor flyttar från landsbygden till städer kräver en mer hållbar stadsplanering för att bekämpa de negativa effekterna av stadsutbredningen. FN:sAgenda 2030 innehåller 17 mål för hållbar utveckling (Sustainable Development Goals, SDG) och 169 delmål som syftar till att förena både utvecklade och utvecklingsländer i att omvandla mänskligheten och planeten för en mer hållbar framtid. Ett av dessa mål är SDG 11, vilket ska göra städer och mänskliga bosättningar inkluderande, säkra, resilient och hållbara. En stor del i att uppnå målen med SDG 11 handlar om den nuvarande tillgången stadsborna har till bland annat offentliga gröna och blå ytor samt kollektivtrafik. Arbetet syftar till att studera Stockholms måluppfyllelse när det gäller SDG 11 delmål 11.2 och 11.7 i Agenda 2030. Föratt mäta uppfyllelsen av dessa delmål har studien följande mål. Det första målet är att studera i vilken grad Stockholms län idag har allmän tillgång till gröna och blå områden och kollektivtrafik genom att genomföra en GIS-baserad analys. Det andra målet är att förbättra vår förståelse för den socioekonomiska statusen hos boende som har respektive inte har tillgång till gröna och blå områden och kollektivtrafik genom att statistiskt analysera sambandet mellan miljöinriktade och socioekonomiska indikatorer. Metoden innefattade kvalitativa metoder som litteraturöversikt, intervjuer och samverkande fokusgruppsmöten med Södertörnsanalysen samt kvantitativa metoder som rumslig analys och statistisk analys. Resultaten visar att medan Stockholm har imponerande hög tillgänglighet för sina invånare, har det ännu inte uppfyllt Agenda 2030 SDG 11 mål 11.2 och 11.7 eftersom det visades att tillgängligheten inte var universell. Resultaten visar också att personer med lägre inkomst, personer som äger sina lägenheter/hem och personer med barn har högre tillgänglighet till grönområden. Det visades också att personer med högre inkomst, personer som hyr sina lägenheter/hem och inte har barn har högre tillgång till kollektivtrafik. Detta resultat kan förväntas eftersom en stor andel personer med högre inkomster bor i innerstaden där de har hög tillgång till kollektivtrafik och urban service, men inte nödvändigtvis grönområden. På ett avstånd av 300 m från bostäder, är både tillgång till grönområden och tillgång tillkollektivtrafik nästan 100 %. Vid ett avstånd av 500 m från bostäder är tillgången till blåområden nära 35 % vilket är långt ifrån alla, men fortfarande en hög andel eftersom tillgång till vattenområden och stränder kan ses som lite av en lyx. Denna studie visar dessutom vikten av att förstå miljö- och socioekonomiska indikatorer i stadsplaneringen, särskilt om målen i Agenda 2030 ska uppfyllas. Denna studie tog också initiativ till att bygga en metod för att kvantifiera tillgängligheten, medan vidare studier behöver genomföras för att ytterligare bidra till stadsplanerings- och utvecklingssektorn.

Prospects for continued use and production of Swedish biogas in relation to current market transformations in public transport

Scipedia content — Tue, 26 Jan 2021 15:27:27 +0100

Biogas is largely utilised as vehicle fuel in public bus transport in Sweden today. This study investigates opportunities and barriers for continued domestic use and production of biogas, in relation to the ongoing electrification of public bus transport. The analysis is based on interviews with actors in public transport and the biogas sector, experts on biogas systems, and representatives for alternative user segments. Three regions were chosen as case-studies for investigations of prospects in public transport, i.e. Stockholm, Västra Götaland and Skåne, though alternative uses were studied from a national perspective. In addition to public transport, considered uses include road transport, sea transport, industries, and electricity and heat production. The study identifies a broad agreement among stakeholders that renewable resources should be implemented where they provide most benefits from a system perspective. Therefore, electric public buses are valued in urban environments, while biogas solutions are found suitable for regional routes. Biogas is further viewed as environmentally beneficial in all user segments except continuous electricity and heat production, where it largely would replace renewable rather than fossil sources. Regarding costs and competitiveness, probable future uses are identified within light and heavy-duty road transport, and in consumer-oriented industries, i.e. the food industry. Economic support in policy instruments is further considered essential for continuous development of the Swedish biogas sector, though current influential instruments, e.g. the tax exemption, are described as short-term and unpredictable. The willingness to pay for the collected societal benefits of biogas further decrease in transitions from public to private consumers, and as biogas solutions simultaneously are linked with limited or uncertain competitiveness in these sectors, risks prevail that such transitions could imply stagnations and declines in biogas use and production, given today’s situation. Idag används biogas till stor del som drivmedel för bussar inom kollektivtrafik i Sverige. Denna studie undersöker möjligheter och hinder för en fortsatt nationell användning och produktion av biogas, i samband med att bussar inom kollektivtrafiken nu elektrifieras. Analysen är baserad på intervjuer med aktörer inom kollektivtrafiken och biogassektorn, sakkunniga inom biogas, och alternativa användare av biogas. Tre regioner, Stockholm, Västra Götaland och Skåne, valdes som fallstudier för analys av möjligheter för fortsatt användning inom kollektivtrafiken. Alternativa användningar studerades istället ur ett nationellt perspektiv, och inkluderade vägtransporter, sjöfart, industri och el- och värmeproduktion. Studien visar att det råder enighet mellan intervjupersoner att förnybara resurser över lag ska användas där de medför störst samhällsnytta sett till samhället i stort. Inom kollektivtrafiken beskrivs elbussar därför som fördelaktiga i stadsmiljöer, medan biogas ses som lämpligt i regional trafik. Biogas framställs dessutom som miljömässigt fördelaktigt i alla alternativa användningsområden utom kontinuerlig el- och värmeproduktion, eftersom då främst förnybara och inte fossila resurser ersätts. Med hänsyn till kostnader och konkurrenskraft ses lätta och tunga transporter tillsammans med kundnära industrier, t.ex. livsmedelsindustrin, som troliga framtida användningsområden för biogas. Ekonomiskt stöd från styrmedel bedöms vara nödvändigt för en fortsatt utveckling av biogassektorn i Sverige, även om dagens styrmedel, t.ex. skattebefrielsen, beskrivs som kortsiktiga och oförutsägbara. Betalningsviljan för biogasens samlade samhällsnyttor minskar också vid en övergång från offentliga till privata kunder. Eftersom biogas därtill har en begränsad eller osäker konkurrenskraft jämtemot andra alternativ i de privata segmenten, identifierar denna studie risker för stagnation eller nedgång i användning och produktion av biogas vid en eventuell utfasning från den offentliga sektorn, givet dagens situation.

Analysis of European market demand for electrical vehicles

Scipedia content — Tue, 26 Jan 2021 15:27:11 +0100

Feasibility and market assessment for EV scheduling and aggregation in European countries.

Scipedia content — Tue, 26 Jan 2021 14:31:47 +0100

Energy system has been going through a revolutionary transformation over the past years. The rising adoption of unpredictable, decentralised renewable energy sources is said to accelerate in the next decades. Variable renewable electricity production in many different locations, can often lead to unexpected and unsought for deviations of gird parameters: frequency and voltage. unsought for devi ations of gird parameters: frequency and voltage, or even congestion of the system. Thus, decentralised electricity system would have a surpassing need of flexibility of the system, which could assure proper regulation of frequency and voltage when needed. The consumption of electricity is also viable and not utterly predictable. To avoid the congestion of electrical grid the demand side response concept has been sprouting. One of the new concepts of demand side response measures is aggregation. Aggregated load regulation envisions gathering and managing numerous small loads, in a way that could stop deviations of frequency and voltage in the system or avoid congestion , without bringing any inconveniences for the owner of the load. EVs while charging, are t hose loads that are often mentioned as aggragatable. With the emerge of massive adoption of Electric Vehicle, secondary uses of it are being questioned. One of them is the idea of balancing the ever changing frequency and voltage in the grid with usage of flexibility created by creating various patterns of charging an electric vehicle. This process is known as Smart Charging. This study integrate s previously mentioned innovations of energy system and analyse the potential of aggregation of electric vehicle s for the purpose of providing flexibility to the electricity system. The thesis will be a technical and economic analysis of the possibility of unlocking this potential in Europe. The regulatory and technical aspects of possible demand side response aggr egation development are presented in the thesis , along with the analysis of Electric Vehicles market and its potential. Thereafter, one exemplary market is analysed further, through developed optimisation model, which allows to assess the value of most imp ortant factors for the aggregator. Three key changing variables are considered in the scheme of charge, those are : the targeted group of clients, the power of the used charger, and the scheme of charging. To assess the importance of those variables the stream of revenues as well as the environmental benefits in the form of potential CO 2 emissions savings are analysed against the variables. E 2 F easibility and market assessment for EV scheduling and aggregation in E uropean countries 2 The major aim and finding of this thesis is to answer the question whether it is plausible to profitab ly develop grid balancing with smart charging of electric vehicles in European Free Trade Association membership countries. The reader will only get to know the answer to that question after flicking through the pages of this paper

Crowdsensing-driven Route Optimisation Algorithms for Smart Urban Mobility

Scipedia content — Tue, 26 Jan 2021 14:28:41 +0100

Urban mobility is often considered as one of the main facilitators for greener and more sustainable urban development. However, nowadays it requires a significant shift towards cleaner and more efficient urban transport which would support for increased social and economic concentration of resources in cities. A high priority for cities around the world is to support residents’ mobility within the urban environments while at the same time reducing congestions, accidents, and pollution. However, developing a more efficient and greener (or in one word, smarter) urban mobility is one of the most difficult topics to face in large metropolitan areas. In this thesis, we approach this problem from the perspective of rapidly evolving ICT landscape which allow us to build mobility solutions without the need for large investments or sophisticated sensor technologies. In particular, we propose to leverage Mobile Crowdsensing (MCS) paradigm in which citizens use their mobile communication and/or sensing devices to collect, locally process and analyse, as well as voluntary distribute geo-referenced information. The mobility data crowdsensed from volunteer residents (e.g., events, traffic intensity, noise and air pollution, etc.) can provide valuable information about the current mobility conditions in the city, which can, with the adequate data processing algorithms, be used to route and manage people flows in urban environments. Therefore, in this thesis we combine two very promising Smart Mobility enablers – MCS and journey/route planning, and thus bring together to some extent distinct research challenges. We separate our research objectives into two parts, i.e., research stages: (1) architectural challenges in designing MCS systems and (2) algorithmic challenges in MCS-driven route planning applications. We aim to demonstrate a logical research progression over time, starting from fundamentals of human-in-the-loop sensing systems such as MCS, to route optimisation algorithms tailored for specific MCS applications. While we mainly focus on algorithms and heuristics to solve NP-hard routing problems, we use real-world application examples to showcase the advantages of the proposed algorithms and infrastructures. Urban rörlighet anses ofta vara en av de främsta möjliggörarna för en hållbar statsutveckling. Idag skulle det dock kräva ett betydande skifte mot renare och effektivare stadstransporter vilket skulle stödja ökad social och ekonomisk koncentration av resurser i städerna. En viktig prioritet för städer runt om i världen är att stödja medborgarnas rörlighet inom stadsmiljöer medan samtidigt minska trafikstockningar, olyckor och föroreningar. Att utveckla en effektivare och grönare (eller med ett ord; smartare) stadsrörlighet är en av de svåraste problemen att bemöta för stora metropoler. I denna avhandling närmar vi oss problemet från det snabba utvecklingsperspektivet av IT landskapet i städer vilket möjliggör byggandet av rörlighetslösningar utan stora stora investeringar eller sofistikerad sensortenkik. I synnerhet föreslår vi utnyttjandet av den mobila rörlighetsavkännings, eng. Mobile Crowdsensing (MCS), paradigmen i vilken befolkningen exploaterar sin mobilkommunikation och/eller mobilasensorer med syftet att frivilligt samla, distribuera, lokalt processera och analysera geospecifik information. Rörlighetavkänningssdata (t.ex. händelser, trafikintensitet, buller och luftföroreningar etc.) inhämtad från frivilliga i befolkningen kan ge värdefull information om aktuella rörelsesförhållanden i stad vilka, med adekvata databehandlingsalgoriter, kan användas för att planera människors rörelseflöden inom stadsmiljön. Såtillvida kombineras i denna avhandling två mycket lovande smarta rörlighetsmöjliggörare, eng. Smart Mobility Enablers, nämligen MCS och rese/ruttplanering. Vi kan därmed till viss utsträckning sammanföra forskningsutmaningar från dessa två delar. Vi väljer att separera våra forskningsmål i två delar, dvs forskningssteg: (1) arkitektoniska utmaningar vid design av MCS-system och (2) algoritmiska utmaningar för tillämpningar av MCS-driven ruttplanering. Vi ämnar att visa en logisk forskningsprogression över tiden, med avstamp i mänskligt dirigerade rörelseavkänningssystem som MCS och ett avslut i automatiserade ruttoptimeringsalgoritmer skräddarsydda för specifika MCS-applikationer. Även om vi förlitar oss på heuristiska lösningar och algoritmer för NP-svåra ruttproblem förlitar vi oss på äkta applikationer med syftet att visa på fördelarna med algoritm- och infrastrukturförslagen. La movilidad urbana es considerada una de las principales desencadenantes de un desarrollo urbano sostenible. Sin embargo, hoy en día se requiere una transición hacia un transporte urbano más limpio y más eficiente que soporte una concentración de recursos sociales y económicos cada vez mayor en las ciudades. Una de las principales prioridades para las ciudades de todo el mundo es facilitar la movilidad de los ciudadanos dentro de los entornos urbanos, al mismo tiempo que se reduce la congestión, los accidentes y la contaminación. Sin embargo, desarrollar una movilidad urbana más eficiente y más verde (o en una palabra, más inteligente) es uno de los temas más difíciles de afrontar para las grandes áreas metropolitanas. En esta tesis, abordamos este problema desde la perspectiva de un panorama TIC en rápida evolución que nos permite construir movilidad sin la necesidad de grandes inversiones ni sofisticadas tecnologías de sensores. En particular, proponemos aprovechar el paradigma Mobile Crowdsensing (MCS) en el que los ciudadanos utilizan sus teléfonos móviles y dispositivos, para nosotros recopilar, procesar y analizar localmente información georreferenciada, distribuida voluntariamente. Los datos de movilidad recopilados de ciudadanos que voluntariamente quieren compartirlos (por ejemplo, eventos, intensidad del tráfico, ruido y contaminación del aire, etc.) pueden proporcionar información valiosa sobre las condiciones de movilidad actuales en la ciudad, que con el algoritmo de procesamiento de datos adecuado, pueden utilizarse para enrutar y gestionar el flujo de gente en entornos urbanos. Por lo tanto, en esta tesis combinamos dos prometedoras fuentes de movilidad inteligente: MCS y la planificación de viajes/rutas, uniendo en cierta medida los distintos desafíos de investigación. Hemos dividido nuestros objetivos de investigación en dos etapas: (1) Desafíos arquitectónicos en el diseño de sistemas MCS y (2) Desafíos algorítmicos en la planificación de rutas aprovechando la información del MCS. Nuestro objetivo es demostrar una progresión lógica de la investigación a lo largo del tiempo, comenzando desde los fundamentos de los sistemas de detección centrados en personas, como el MCS, hasta los algoritmos de optimización de rutas diseñados específicamente para la aplicación de estos. Si bien nos centramos en algoritmos y heurísticas para resolver problemas de enrutamiento de clase NP-hard, utilizamos ejemplos de aplicaciones en el mundo real para mostrar las ventajas de los algoritmos e infraestructuras propuestas. "p"QC 20180926

Study and development of a device tracking software

Scipedia content — Tue, 26 Jan 2021 14:28:09 +0100

quest projecte consisteix a desenvolupar una nova versió de l'API de geolocalització de TooPath utilitzant les tecnologies actuals. La nova versió oferirà un sistema de seguiment per a qualsevol tipus de dispositiu electrònic i una web per consumir i demostrar les funcionalitats de l'API.

Attitude and intention to use carsharing in Portugal: users and non-users

Scipedia content — Tue, 26 Jan 2021 14:26:20 +0100

Carsharing is a service that allows the rental of a car to the minute, providing more flexibility to the user. This service appeared in 1948 in Switzerland but it has been growing due to the awareness of Shared Mobility. Carsharing concept has been approached by several researchers. However, there is not so much literature about Portuguese market. The impacts of carsharing are known to be the reduction of C02 emissions since it contributes to the reduction of the number of cars parked and in circulation in the big cities (1), the inclusion of all fixed costs in the final price, as the user only pays the miles he drives (2) and the flexibility carsharing gives the users to move around in the city (3). This study’s goal is to understand the Portuguese perception of carsharing use, taking into account benefits such as convenience, environmental impact and costs considerations. It is also crucial to understand the level of service knowledge among Portuguese people, since this factor can influence the perception and a possible intention to use it. It turns out that most of the Portuguese know what carsharing is but do not know very well how it works. In general, the Portuguese people, whether users or non-users, do not see carsharing as a cheap service, but consider the service convenient. As far as environmental impact is concerned, attitudes differ. Users have a positive attitude regarding carsharing impact on the environment, while non-users have a negative attitude. This perception impacts on the attitude of users and non-users. While the former has a positive attitude towards the use of carsharing, the same cannot be concluded from the latter. Most users intend to continue to use carsharing, unlike most non-users who do not want to try the service. O carsharing é um serviço que permite o aluguer de um carro ao minuto, proporcionando mais flexibilidade ao utilizador. Este serviço apareceu pela primeira vez em 1948 na Suíça e tem vindo a crescer devido à popularidade do fenómeno da Mobilidade Partilhada. O carsharing tem sido um conceito muito abordado por investigadores estrangeiros, nunca tendo sido muito investigado em Portugal. Os impactos do carsharing são conhecidos por ser a redução de emissões de C02 uma vez que contribui para a diminuição do número de carros estacionados e em circulação nas grandes cidades (1), a não inclusão de custos fixos que a utilização de carro próprio acarreta no preço final- o utilizador só paga os quilómetros que conduz (2) e a flexibilidade que dá aos utilizadores para se movimentarem na cidade (3). Este estudo tem como objetivo perceber qual é a perceção dos portuguese face à utilização do carsharing, tendo em conta benefícios como a conveniência, o impacto ambiental e fatores económicos. Torna-se crucial perceber também o nível de conhecimento do serviço por parte dos portugueses, uma vez que este fator pode influenciar a perceção e uma possível intenção de utilização do mesmo. Conclui-se que a maior parte dos portugueses sabe o que é carsharing mas não sabe muito bem como funciona. Em geral, os portugueses, quer utilizadores quer não utilizadores, não veem o carsharing como um serviço barato, mas consideram o serviço conveniente. No que diz respeito ao impacto ambiental, as atitudes divergem. Os utilizadores têm uma atitude positiva quanto ao impacto do carsharing no ambiente, enquanto os não utilizadores têm uma atitude negativa. Esta perceção impacta na atitude dos utilizadores e não utilizadores. Enquanto que os primeiros têm uma atitude positiva face à utilização de carsharing, já não se pode concluir o mesmo dos segundos. Na sua maioria os utilizadores pretendem continuar a utilizar carsharing, ao contrário da maioria dos não utilizadores que não pretende experimentar o serviço.

An investigation of freeway standstill distance, headway, and time gap data in heterogeneous traffic in Iowa

Scipedia content — Tue, 26 Jan 2021 14:24:47 +0100

Microsimulation models have been growing in popularity in traffic engineering in recent years, and are often used as an important tool in the decision making process on large roadway design projects. In order to get valid results, it is necessary to calibrate such microsimulation models to local conditions. This is frequently achieved through a trial and error process of adjusting model parameters to get simulation results to match real world calibration data. Rarely is data collected on the model parameters themselves to provide a physical basis for the selection of their value. Two of the most important microsimulation model parameters for freeway models are standstill distance (the distance between stopped vehicles) and preferred time headway or time gap (the time between successive vehicles). Many simulation models treat these values as constants for all drivers and do not allow them to be set separately for different vehicle classes. This study presents a repeatable methodology for collecting standstill distance and headway/time gap values on freeways (mostly urban, with one rural location). It applies that methodology to locations throughout the state of Iowa. It continues by analyzing that data and comparing it for different locations and conditions. It finds that standstill distances vary by location and vehicle pair type. Headways/time gaps are found to be consistent within the same driver population and across different driver populations when the conditions are similar. An initial comparison between headways/time gaps at three urban areas to one rural location indicates a potential difference in driver behavior between those two conditions. Both standstill distance and headway/time gap are found to follow fairly disperse and skewed distributions. As a result of these findings, it i

Model based control system development for the thermal management of a fuel cell powered passenger car

Scipedia content — Tue, 26 Jan 2021 14:23:58 +0100

cooling system for a fuel cell (FC) powered car within the framework of a European project called INN-BALANCE is currently being developed at the German aeronautics and space research centre (DLR). Given a design of the cooling loop, a thermal model of it has been developed in this master thesis making use of the software Matlab Simulink™, as it is the official simulation program for the INN-BALANCE project and the one used to share all the models between the project partners. Once the thermal model was developed, a control system for the next key components of this cooling system has been designed: the 3-way valve (or bypass valve), the fan of the radiator, the main pump of the circuit and the pump and heater of a heating system meant to be used in very low ambient temperatures. The goal of this control system has been to keep the coolant inlet and outlet of the FC at temperatures of 68℃ and 80℃ respectively, or more specifically, to keep a maximum temperature difference between the FC inlet and outlet of 12K. The designed control system has been tested on a test bed whose components are slightly different to the ones that will be used on the resulting car of the INN-BALANCE project, however the goal was also to develop a control system robust enough to be able to cope with any changes on the dimensions and typology of the components. For this purpose, the test bench used has a heat exchanger whose coolant pressure loss between inlet and outlet is very similar to the one of the FC to substitute it. Another key component different on the test bench is the radiator, whose dimensions are not the definitive ones and the same applies for the fan that blows air through it. The experiments performed at the test bench showed a control system capable of keeping the temperatures at the desired levels as long as the heat dissipation capabilities of the cooling system are not surpassed. Outgoing

Adaptative strategy for data dissemination using signal strenght

Scipedia content — Tue, 26 Jan 2021 14:23:35 +0100

Rede Ad hoc Veicular (VANET) é um subconjunto singular das redes ad hoc móveis (MANET), com o diferencial de que os nós são veículos providos de tecnologia própria de comunicação e que interagem para formar redes espontâneas, valendo-se de pouca ou nenhuma infraestrutura estabelecida previamente. VANETs admitem a integração de diferentes tecnologias sem fio na pretensão de mitigar adversidades, agregar segurança e eficiência ao tráfego. Na disseminação de dados, um salto único é suficiente para orientar os elementos ao alcance do sinal de rádio, e nós intermediários sustentam a comunicação aos demais, em encaminhamento multihop. Amparados em dispositivos embarcados, os veículos produzem registros, detectam sinais, trocam advertências e métricas. Avaliações dessas informações permitem ao condutor decisões ou reações antecipadas em situações adversas, a exemplo dos acidentes ou congestionamentos. Nesse contexto, a execução deste trabalho trata questões para elaborar estratégias adaptativas inteligentes de disseminação de dados, uma vez que as mesmas se consolidam como lastros da comunicação em VANET com condições adversas de operação. A abordagem proposta se utiliza de sistemas fuzzy para a detecção de congestionamento, com o propósito de agregar autonomia e adaptar a estratégia de disseminação às condições de tráfego identificadas. A convergência nos desenvolvimentos realizados se reflete na estratégia eFIRST, uma solução robusta para a detecção autônoma da condição atual de congestionamento que resguarda a disseminação adaptativa de alertas e abranda o problema da interrupção no tráfego. A abordagem se sustenta apenas na comunicação entre veículos e nos registros de identificação da vizinhança local, agregados em uma estratégia fuzzy e no ajuste adaptativo da potência do sinal de transmissão. Em conformidade com as tendências de condução e com os sistemas inteligentes, este desenvolvimento contribui com subsídios para ratificar a aproximação fuzzy como estratégia adaptativa às flutuações na densidade veicular, em diferentes cenários e regimes de tráfego. As avaliações comparativas do eFIRST respaldam concluir que a estratégia oportuniza o equilíbrio otimizado das perdas, colisões e cobertura, com superior alcance de propagação e redução dos congestionamentos. Vehicular Ad hoc Network (VANET) is a unique subset of mobile ad hoc networks (MANET), with the difference that nodes are vehicles provided with their own communication technology and interact to form spontaneous networks, with little or no infrastructure previously established. VANETs support the integration of different wireless technologies in order to mitigate adversities, add security and efficiency to traffic. In the data dissemination, a single hop is sufficient to guide the elements within reach of the radio signal, and intermediary nodes support the communication with the others in multihop routing. Supported by embedded devices, vehicles produce records, detect signals, exchange warnings and metrics. Assessments of this information allow the driver to make decisions or react beforehand in adverse situations, such as accidents or traffic congestions. From the observations in this context, this work deals with questions to elaborate intelligent adaptive strategies in data dissemination, since they consolidate themselves as ballast communication in VANET with adverse operating conditions. The proposed approach uses fuzzy systems to detect traffic congestion, with the purpose of aggregating autonomy and adapting the dissemination strategy to the identified traffic conditions. The convergence in the developments performed is reflected in the eFIRST strategy, a robust solution for the autonomous detection of the current traffic congestion condition that protects the adaptive dissemination of alerts and reduces the problem of the interruption in the traffic. The approach is supported only by communication between vehicles and in local neighborhood identification records, aggregated in a fuzzy strategy and in the adaptive adjustment of transmission signal power. In accordance with the driving trends and with the intelligent systems, this development contributes with assistance for ratify the fuzzy approach as an adaptive strategy to fluctuations in vehicular density in different scenarios and traffic regimes. Comparative evaluations of eFIRST support the conclusion that the strategy favors the optimal balance of losses, collisions and coverage, with a greater range of propagation and reduction of congestion.

Development and validation of virtual interactive tasks for an aviation English assessment

Scipedia content — Tue, 26 Jan 2021 14:21:06 +0100

Instable ship motions applied on ship weather routing algorithm simroutev2

Scipedia content — Tue, 26 Jan 2021 14:19:37 +0100

Some combinations of wave length and wave height under certain operational condi-tions may lead to dangerous unstable motions for ships in accordance with the IS Code. The susceptibility of a ship to dangerous phenomenon will depend on the stabil-ity parameters, ship speed, hull shape and ship size. This signifies that the vulnerabil-ity to dangerous responses, including capsizing, and its probability of occurrence in a singular sea state may differ for each ship. During navigation periods these unstable motions are able to be encountered, which may lead to a cargo or equipment damage and the unsafety of the persons on board. The main reason for these causes is rarely known and currently there are just few work such as the International Maritime Organ-ization guidelines which tries to ensure adequate dynamic stability (IMO, MSC.1/Circ.1228, 2007). Ship routing systems are gaining importance in the maritime sector as the use of these systems can lead to the reduction of fuel usage and reduce costs. Therefore, a mitiga-tion of carbon emis¬sions and improvement of maritime safety happens due to the avoidance of bad weather conditions. The implementation of pathfinding algorithms to determine the optimal ship routing has been widely used for transoceanic distances. However, the evaluation of short distance routes with ship-weather routing algorithms is still scarce, due to the low spatial resolution of wave fields. Mixing both concepts, that is to say, implementing the ship routing system with com-mon unstable motions makes the algorithm more complete and useful than it was. Thus, equipping ships with these systems will be profitable for the officers because they will be able to modify the stablished route or, at least, alter the course depending on the danger faced. Results derived from such calculations should only be regarded as a supporting tool during the decision-making process.

Propuesta metodológica para aplicar logística colaborativa a la demanda de servicios logísticos desde minoristas de productos agrícolas de una localidad de Bogotá

Scipedia content — Tue, 26 Jan 2021 14:18:54 +0100

Este trabajo investigativo propone una metodología para aplicar la estrategia de logística colaborativa a la cadena de suministro de productos agrícolas que abastece una localidad en Bogotá. Se realiza una revisión de literatura que permite identificar la estructura y factores determinantes de éxito en la estrategia colaborativa para la gestión de la cadena de suministro, paralelamente se realiza un caracterización in situ de la cadena de suministro objeto de estudio, que permite identificar las ineficiencias susceptibles de mejora, en función de la cual se diseña la metodología propuesta tal que armonice los principios de operación logística colaborativa de la cadena de suministro adaptada a las particularidades del objeto de estudio. Se obtiene una metodología que, aun cuando diseñada en función de la cadena de suministro objeto de este estudio, conserva una estructura genérica flexible que constituye una útil herramienta que apoya la puesta en práctica de las bondades teóricas de la administración de la cadena de suministro, soportando una ventaja competitiva para el sistema productivo. Abstract: This research project proposes a methodology for the collaborative logistics strategy for the supply chain of agricultural products that supplies a locality in Bogotá. A review of the literature is carried out to identify the structure and determining factors of success in the collaborative strategy for the management of the supply chain, at the same time an in situ characterization of the chain of services under study is carried out, which makes it possible to identify the inefficiencies susceptible to improvement, based on which the proposed methodology is designed, that the principles of the collaborative logistics operation of the supply chain are adapted to the particularities of the object of study. A methodology can be obtained that, even though it has been designed according to the supply chain of object of study, a flexible generic structure that is a useful tool that supports the implementation of the therapeutic benefits of the administration of the chain of supply, supporting a competitive advantage for the productive system

Estudo e simulação de sistemas fotovoltaicos híbridos para aplicação autônoma e conectada à rede

Scipedia content — Tue, 26 Jan 2021 14:15:17 +0100

Orientador: Marcelo Gradella Villalva Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Made available in DSpace on 2020-07-16T12:34:30Z (GMT). No. of bitstreams: 1 Costa_TatianeSilva_M.pdf: 10047263 bytes, checksum: 72cb9e310104d577b00347ccc8658f51 (MD5) Previous issue date: 2019 Resumo: Os sistemas híbridos de energia tem atraído o uso de consumidores dentro e fora da rede elétrica por dispor de aspectos de confiabilidade, sustentabilidade e agregar o uso de múltiplas fontes como de sistemas de energia solar, sistemas eólicos, redes elétricas interligadas e grupo geradores a diesel. Apesar desses sistemas terem atingido certo grau de maturidade, as pesquisas a cerca desse tema em relação aos estudos de dimensionamento, desempenho, controle e gerenciamento dos sistemas continuam sendo atuais por diversos motivos, como a diminuição de emissão de gases de efeito estufa, a popularização de geração distribuída, a inserção de novas cargas como veículos elétricos e a universalização da energia elétrica. Nesta dissertação é abordado dois estudos de caso sobre sistemas híbridos conectados à rede e autônomos utilizando a ferramente de modelagem Homer Energy com o uso de cargas típicas residenciais e de veículos elétricos. O primeiro caso é um sistema fotovoltaico-diesel na Reserva Extrativista Tapajós-Arapiuns e o segundo caso trata do sistema fotovoltaico-bateria conectado à rede para a alimentação de um eletroposto do projeto de mobilidade elétrica da UNICAMP. As simulações apresentam para ambos os casos resultados sobre balanço energético, validação e participação dos recursos energéticos, perfomance dos componentes e viabilidade técnica dos projetos Abstract: Hybrid power systems have attracted the use of consumers on and off the grid because of their reliability, sustainability and aggregate use of multiple sources such as solar power systems, wind power systems, interconnected power grids, and diesel generator sets. Although these systems have reached a certain degree of maturity, research on this topic about systems sizing, performance, control, and management studies is still current for several reasons, such as the reduction of greenhouse gas emissions, popularization. distributed generation, the insertion of new loads such as electric vehicles and the universalization of electric energy. This dissertation discusses two case studies on autonomous and grid-connected hybrid systems using the Homer Energy modeling tool using typical residential loads and electric vehicles. The first case is a photovoltaic-diesel system in the Tapajós-Arapiuns Extractive Reserve and the second case deals with the photovoltaic battery system connected to the grid to power an charging station from the UNICAMP electric mobility project. The simulations present for both cases results on energy balance, validation, and participation of energy resources, the performance of the components and technical viability of the projects Mestrado Energia Eletrica Mestra em Engenharia Elétrica 88882.329359/2019-01 CAPES

Connected Vehicles for Internet Access: Deployment and Spectrum Policies

Scipedia content — Tue, 26 Jan 2021 14:13:42 +0100

Internet traffic from mobile users has been growing sharply. To meet the needs of those"br"users, it is important to expand capacity of networks that provide Internet access in cost effective"br"ways. This capacity has traditionally been provided by cellular networks. However,"br"expanding the capacity of those networks alone may not be the most cost-effective way to meet"br"the present and future growth of mobile Internet under some circumstances. In this dissertation,"br"we show that networks of connected vehicles can be an important way to complement the"br"capacity of cellular networks to provide mobile Internet access under several scenarios."br"Connected vehicles may soon be widely deployed, forming mesh networks of short-range"br"connections among vehicles and between vehicles and roadside infrastructure. These"br"connections are collectively referred to as vehicle-to-everything, or V2X. Deployment of"br"connected vehicles and infrastructure is primarily intended to enhance road safety, and the U.S."br"Department of Transportation has recently proposed a mandate of V2X devices in vehicles"br"using Dedicated Short Range Communications (DSRC) technology. Other applications are also"br"envisioned that include Internet access in vehicles connecting to roadside infrastructure serving"br"as gateways to the Internet."br"In this work, we find that V2X-based networks are more cost-effective than cellular to"br"provide Internet access, in scenarios which DSRC devices are mandated in vehicles to enhance"br"road safety. This is true initially for densely populated urban areas, but over time V2X-based"br"networks would be cost-effective in less populated areas as well, as long as Internet traffic or"br"penetration of V2X devices grow as expected."br"Local and state governments are expected to deploy roadside infrastructure for safety"br"applications. If that infrastructure is shared with Internet Service Providers for a fee, then V2XABSTRACT based networks are cost-effective in locations with even lower population densities than the"br"locations where it is cost-effective to deploy infrastructure for Internet access only. Moreover,"br"the sharing fee could help governments save in infrastructure costs. We find the pricing"br"strategies that maximize either cost-effectiveness or government savings. We estimate that"br"governments could save about one-fifth of the total cost to deploy safety infrastructure"br"nationwide in the U.S., if fees are set to maximize government savings. Although we find that"br"these prices may differ from the pricing strategy that maximizes cost-effectiveness, maximizing"br"government savings results in near-optimal cost-effectiveness."br"The U.S. Federal Communications Commission has allocated 75 MHz of spectrum to be"br"used exclusively by DSRC devices, and it has been hotly debated whether all or part of that"br"bandwidth should be shared with unlicensed devices. We find that it is highly efficient to share"br"any spectrum allocated to V2X communications beyond the portion of that spectrum that is"br"needed for safety-critical DSRC messages. V2X and unlicensed devices require up to 50% less"br"bandwidth on shared spectrum to achieve given throughputs, compared to V2X and unlicensed"br"devices using separate bands. We conclude that the spectrum available for V2X should be"br"maintained or increased, as long as much of that spectrum is shared with non-V2X devices."br"Conclusions are derived from an engineering-economic approach, in which part of the"br"assumptions are based on data from a citywide deployment of connected vehicles in Portugal."br"The data is used in a detailed and realistic packet-level simulation model of V2X-based"br"networks used to provide Internet access with DSRC technology. In some scenarios, the"br"simulation also includes unlicensed devices using Wi-Fi technology. The results of the network"br"simulation are then fed into engineering-economic models to compare costs of V2X-based"br"networks with costs of macrocellular networks to carry given amounts of Internet traffic, and to"br"estimate other measures such as government revenues and spectrum usage. Those measures"br"help inform decisions about where and when to deploy V2X-based networks, decisions about whether and how to promote public-private partnerships to deploy V2X infrastructure, and"br"decisions about sharing spectrum used for V2X communications with non-V2X devices. "br

Development of Predictive Vehicle Control System using Driving Environment Data for Autonomous Vehicles and Advanced Driver Assistance Systems

Scipedia content — Tue, 26 Jan 2021 14:12:53 +0100

In the field of modern automotive engineering, many researchers are focusing on the development of advanced vehicle control systems such as autonomous vehicle systems and Advanced Driver Assistance Systems (ADAS). Furthermore, Driver Assistance Systems (DAS) such as cruise control, Anti-Lock Braking Systems (ABS), and Electronic Stability Control (ESC) have become widely popular in the automotive industry. Therefore, vehicle control research attracts attention from both academia and industry, and has been an active area of vehicle research for over 30 years, resulting in impressive DAS contributions. Although current vehicle control systems have improved vehicle safety and performance, there is room for improvement for dealing with various situations. The objective of the research is to develop a predictive vehicle control system for improving vehicle safety and performance for autonomous vehicles and ADAS. In order to improve the vehicle control system, the proposed system utilizes information about the upcoming local driving environment such as terrain roughness, elevation grade, bank angle, curvature, and friction. The local driving environment is measured in advance with a terrain measurement system to provide terrain data. Furthermore, in order to obtain the information about road conditions that cannot be measured in advance, this work begins by analyzing the response measurements of a preceding vehicle. The response measurements of a preceding vehicle are acquired through Vehicle-to-Vehicle (V2V) or Vehicle-to-Infrastructure (V2I) communication. The identification method analyzes the response measurements of a preceding vehicle to estimate road data. The estimated road data or the pre-measured road data is used as the upcoming driving environment information for the developed vehicle control system. The metric that objectively quantifies vehicle performance, the Performance Margin, is developed to accomplish the control objectives in an efficient manner. The metric is used as a control reference input and continuously estimated to predict current and future vehicle performance. Next, the predictive control algorithm is developed based on the upcoming driving environment and the performance metric. The developed system predicts future vehicle dynamics states using the upcoming driving environment and the Performance Margin. If the algorithm detects the risks of future vehicle dynamics, the control system intervenes between the driver's input commands based on estimated future vehicle states. The developed control system maintains vehicle handling capabilities based on the results of the prediction by regulating the metric into an acceptable range. By these processes, the developed control system ensures that the vehicle maintains stability consistently, and improves vehicle performance for the near future even if there are undesirable and unexpected driving circumstances. To implement and evaluate the integrated systems of this work, the real-time driving simulator, which uses precise real-world driving environment data, has been developed for advanced high computational vehicle control systems. The developed vehicle control system is implemented in the driving simulator, and the results show that the proposed system is a clear improvement on autonomous vehicle systems and ADAS. Ph. D.

Design and operation of mesh-restorable WDM networks

Scipedia content — Tue, 26 Jan 2021 14:10:08 +0100

The explosive growth of Web-related services over the Internet is bringing millions of new users online, thus creating a growing demand for bandwidth. Wavelength Division Multiplexed (WDM) networks, employing wavelength routing has emerged as the dominant technology to satisfy this growing demand for bandwidth. As the amount of traffic carried is larger, any single failure can be catastrophic. Survivability becomes indispensable in such networks. Therefore, it is imperative to design networks that can quickly and efficiently recover from failures. In this dissertation, we explore the design and operation of survivable optical networks. We study several survivability paradigms for surviving single link failures. A restoration model is developed based on a combination of these paradigms. We propose an optimal design and upgrade scheme for WDM backbone networks. We formulate an integer programming-based design problem to minimize the total facility cost. This framework provides a cost effective way of upgrading the network by identifying how much resources to budget at each stage of network evolution. This results in significant cost reductions for the network service provider. As part of network operation, we capture multiple operational phases in survivable network operation as a single integer programming formulation. This common framework incorporates service disruption and includes a service differentiation model based on lightpath protection. However, the complexity of the optimization problem makes the formulation applicable only for network provisioning and o2ine reconfiguration. The direct use of such methods for online reconfiguration remains limited to small networks with few tens of wavelengths. We develop a heuristic algorithm based on LP relaxation technique for fast, near optimal, online reconfiguration. Since the ILP variables are relaxed, we provide a way to derive a feasible solution from the relaxed problem. Most of the current approaches assume centralized information. They do not scale well as they rely on per-flow information. This motivates the need for developing dynamic algorithms based on partial information. The partial information we use can be easily obtained from traffic engineering extensions to routing protocols. Finally, the performance of partial information routing algorithms is compared through simulation studies.

Optimal Charging Scheduling for Electric Vehicles Based on a Moving Horizon Approach

Scipedia content — Tue, 26 Jan 2021 14:08:49 +0100

The rapid escalation in plug-in electric vehicles (PEVs) and their uncoordinated charging patterns pose several challenges in distribution system operation. Some of the undesirable effects include overloading of transformers, rapid voltage fluctuations, and over/under voltages. While this compromises the consumer power quality, it also puts on extra stress on the local voltage control devices. These challenges demand a well-coordinated and power network-aware charging approach for PEVs in a community. This paper formulates a realtime electric vehicle charging scheduling problem as a mixed-integer linear program (MILP). The problem is to be solved by an aggregator that provides charging services in a residential community. The proposed formulation maximizes the profit of the aggregator, enhancing the utilization of available infrastructure. With prior knowledge of load demand and hourly electricity prices, the algorithm uses a moving time horizon optimization approach, allowing an unknown number of arriving vehicles. In this realistic setting, the proposed framework ensures that power system constraints are satisfied and guarantees the desired PEV charging level within the stipulated time. Numerical tests on an IEEE 13-node feeder system demonstrate the computational and performance superiority of the proposed MILP technique. M.S. There is an enhanced rate of global warming due to emissions and increased usage of fossil fuels in the transportation sector. As a feasible solution, electrification of transportation has become a necessary step towards an environment-friendly future. The escalation in plug-in electric vehicles (PEVs) has increased the impact on loading and voltage fluctuations in the distribution grid due to uncoordinated charging. This puts on extra stress on the grid system and compromises the system performance. As a measure to control the vehicle charging in a residential setup, a real-time optimal charging scheduling algorithm is developed which is implemented at the neighborhood level. To increase the charging performance with the limited available resources, an aggregator is introduced. The charging profit is maximized as the PEV charging problem is solved optimally by the aggregator. This facilitates the reduction in night-time grid congestion and maximization of number of PEVs getting charged with limited dependency on communication to avoid long delays in charging control. The proposed technique guarantees the complete charging of the selected PEVs in the stipulated time while considering the power grid operational constraints. It also reduces the impact of peak load demand by flattening the base load demand curve. To demonstrate the efficiency of the proposed mixed integer linear programming optimization algorithm, numerical tests for an IEEE 13 node feeder are performed. The results are discussed to give an outlook on the balance between system and user requirements by meeting the demand of the PEV users.

Assembly Line Design for Electric Driven Vehicles (or Powertrain) : Investigation of using Smart Manufacturing Technologies in Concept Designs for Assembly Lines

Scipedia content — Tue, 26 Jan 2021 14:07:13 +0100

With the rise of smart manufacturing technologies and a shift towards a new industrial revolution, brings forth many new challenges, one of which is how to adapt and integrate these technologies into existing assembly lines. Scania CV AB has joined this race and, with the help of smart manufacturing solutions, works on increasing efficiency amongst its assembly lines. This thesis is aimed at creating concept designs using different smart manufacturing technologies in the assembly line of a pedal car, to evaluate and adapt the concept suited for a real assembly line. The thesis starts with studying the different smart manufacturing technologies to better understand them and the scientific methods used. This follows up with the methodology where several scientific methods such as morphological matrix and weight based decision making matrix are used to generate and evaluate different concept designs. This is followed by a qualitative analysis that helps in selecting the concept design that best suits the needs of the assembly line under consideration. The different concepts are visualized and the evaluation based on different parameters are discussed. This thesis lays a foundation to realize that an aggregate of an optimized process plan, a continuous improvement strategy and the right use of smart manufacturing technologies contributes to the productivity of the assembly line in the long run. Med en ökning av smarta tillverkningsteknologier och ett skift mot en ny industriell revolution, kommer nya utmaningar. Av dessa utmaningar ifrågasätts hur man anpassar och kombinerar dessa olika teknologier gentemot existerande monteringslinjer. Scania CV AB har tagit del i denna resa och, med hjälp av smarta tillverkningslösningar, jobbar ständigt mot att effektivisera sina monteringslinjer. Detta examensarbete fokuserar på att använda olika och smarta tillverkningsteknologier i en monteringslina för tillverkning av en trampbil. Detta görs genom att evaluera och anpassa olika koncept som är lämpade för en verklig monteringslina. Examensarbetet börjar med en undersökning av nuläget för att få en bättre uppfattning om smarta tillverkningsteknologier samt de vetenskapliga metoder som används. Även här så undersöks referensprodukten - trampbil samt de olika programvarorna AviX, ExtendSim och LayCAD. Genom att ha satt tydliga arbetsmetoder och följt upp mot dessa så diskuterar och hänvisar nästa kapitel resultaten. Resultaten visar hur olika koncept har tagits fram samt vilka teknologier som går ihop med dessa. Fördelar, nackdelar och risker hos respektive teknologi har benämnts. Ett systematiskt arbetssätt har tagits fram mot hur man anpassar konceptet för monteringslinan av en trampbil till en verklig monteringslina, samt hur man har jobbat runt de restriktioner som uppkommit. Examensarbetet slutar med ett kapitel där slutsatserna, på en överskådlig nivå, tas fram. Hur dessa teknologier har kombinerats och evaluerats, samt att koncepterna som har tagits fram har lagt en grund för framtida projekt att följa upp emot.

Speed metrics and crash risks: statistical assessment and implications for highway safety policy

Scipedia content — Tue, 26 Jan 2021 14:05:43 +0100

Advanced Modelling of NiMH Batteries: Integrating Renewable Energy Sources into EV Charging Stations

Scipedia content — Tue, 26 Jan 2021 14:02:22 +0100

This thesis is devoted to the topic of energy storage system modelling, and to the integration of such systems to increase the utilisation of renewable energy. In particular, the use of a nickel-metal hydride battery storage system is considered in combination with energy produced by solar and wind to power an electric vehicle fast-charging station situated in Norway. The thesis aims to develop a flexible model for the battery energy storage system that can accurately describe battery performance and performance-reducing effects. The motivation of which is to be able to evaluate the feasibility of the charging topology in mention. A semi-empirical, battery model based on real data is designed and implemented in the Simulink modelling environment. Further, a system model is developed in the same modelling environment which uses actual data from Norwegian renewable energy producers and charging station operators. We report on the influence of renewable energy mixture, capacity sizing, production sizing and vehicle charging behaviour on the feasibility of the topology. The thesis is written as a contribution of the now finished project INTEGRARE (Intelligent prediction and integration of renewable energy sources into the Norwegian electricity grid, headed by the Department of Technology Systems). The topic is in line with an ongoing effort in the energy storage system research group to promote, design, model and validate the feasibility of energy systems powered by renewable energy sources.