Scipedia: Documents published in 2014

Multi-state supernetworks: recent progress and prospects

Scipedia content — Mon, 15 Feb 2021 10:12:32 +0100

Supernetworks have long been adopted to address multi-dimensional choice problems, which are thorny to solve for classic singular networks. Originated from combining transport mode and route choice into a multi-modal network, supernetworks have been extended into multi-state networks to include activity-travel scheduling, centered around activity-based models of travel demand. A key feature of the network extensions is that multiple choice facets pertaining to conducting a full activity program can be modeled in a consistent and integrative fashion. Thus, interdependencies and constraints between related choice facets can be readily captured. Given this advantage of integrity, the modeling of supernetwork has become an emerging topic in transportation research. This paper summarizes the recent progress in modeling multi-state supernetworks and discusses future prospects.

Document type: Article

Digital Advertising System in Urban Transport System of Žilina Town

Scipedia content — Mon, 15 Feb 2021 09:58:13 +0100

The Internet and information and communication technologies (ICT) have changed everything: news, commerce, advertising, relating to others, getting information and transport too. It has changed how the people work, how they practice religion, how they date, how they spend the free time and how they travel. One of the technological innovations that are based on usage ICT in advertising space is digital signage. This article presents the results of research dedicated to investigate the relationships between customers-passengers and this new ICT technology in real environment. The results of the research stimulate the discussion about the future advertising practices in Žilina town. Based on the wide analysis of opportunities the digital signage technology in advertising practices, the presented marketing research investigates how passengers accept virtual advertising technology in urban transport system of Žilina town. Authors highlight the advantages of interactivity between digital signage technology and consumers. The conclusions of this article triggers further investigations in the area of the interactions between the digital advertising technology and passengers, and the passengers’ perception and acceptation of shopping activities on the basis of advertising in digital signage medias.

Document type: Article

A straightforward and efficient analytical pipeline for metaproteome characterization

Scipedia content — Mon, 15 Feb 2021 09:47:42 +0100

Background The massive characterization of host-associated and environmental microbial communities has represented a real breakthrough in the life sciences in the last years. In this context, metaproteomics specifically enables the transition from assessing the genomic potential to actually measuring the functional expression of a microbiome. However, significant research efforts are still required to develop analysis pipelines optimized for metaproteome characterization. Results This work presents an efficient analytical pipeline for shotgun metaproteomic analysis, combining bead-beating/freeze-thawing for protein extraction, filter-aided sample preparation for cleanup and digestion, and single-run liquid chromatography-tandem mass spectrometry for peptide separation and identification. The overall procedure is more time-effective and less labor-intensive when compared to state-of-the-art metaproteomic techniques. The pipeline was first evaluated using mock microbial mixtures containing different types of bacteria and yeasts, enabling the identification of up to over 15,000 non-redundant peptide sequences per run with a linear dynamic range from 104 to 108 colony-forming units. The pipeline was then applied to the mouse fecal metaproteome, leading to the overall identification of over 13,000 non-redundant microbial peptides with a false discovery rate of "1%, belonging to over 600 different microbial species and 250 functionally relevant protein families. An extensive mapping of the main microbial metabolic pathways actively functioning in the gut microbiome was also achieved. Conclusions The analytical pipeline presented here may be successfully used for the in-depth and time-effective characterization of complex microbial communities, such as the gut microbiome, and represents a useful tool for the microbiome research community. Electronic supplementary material The online version of this article (doi:10.1186/s40168-014-0049-2) contains supplementary material, which is available to authorized users.

Document type: Article

Analysis of Urban Car Owners Commute Mode Choice Based on Evolutionary Game Model

Scipedia content — Mon, 15 Feb 2021 09:43:55 +0100

With the aggravation of the traffic congestion in the city, car owners will have to give up commuting with private cars and take the public transportation instead. The paper uses the replication dynamic mechanism to simulate the learning and adjustment mechanism of the automobile owners commuting mode selection. The evolutionary stable strategy is used to describe the long-term evolution of competition game trend. Finally we simulate equilibrium and stability of an evolution of the game under a payoff imbalance situation. The research shows that a certain proportion of car owners will choose public transit under the pressure of public transport development and heavy traffic, and the proportion will be closely related to the initial conditions and urban transportation development policy.

Document type: Article

Identification of Prior Factors Influencing the Mode Choice of Short Distance Travel

Scipedia content — Fri, 12 Feb 2021 15:13:57 +0100

Short distance trips are defined as any trips shorter than or equal to 5 kilometers, which have been found to be a big contributor to the traffic congestion problem. This paper is intended to analyze factors that influence the mode choice of short distance travels in order to help reduce short distance trips by cars. A survey is conducted at two typical kinds of residential areas, one with a high proportion of short distance car trips and another one with a low proportion. Then, by applying the structural equation modeling, it is found that the age, the household income, and the vehicle ownerships have a significant effect on the mode choice of short distance travels. Besides, among residents of the same type (same age, household income, and vehicle ownerships) in surveyed areas, those in the area with a better green-mode travel environment account for a higher proportion choosing the green mode than those in other areas. Based on this result, it is concluded that a better green-mode travel environment leads to a higher proportion of green-mode travels. In the end, the paper shows residents’ stated willingness to change travel modes from cars to the green mode.

Document type: Article

Logistics freight center locations decision by using Fuzzy-PROMETHEE

Scipedia content — Fri, 12 Feb 2021 15:08:37 +0100

Fuzzy Preference Ranking Organization METHod for Enrichment Evaluation (F-PROMETHEE) was applied for choosing among potential logistics center locations. The method combines the concept of fuzzy sets to represent uncertain information with the PROMETHEE, a subgroup of Multi-Criteria Decision-Making (MCDM) methods. Criteria are identified based on review of scientific and trade literature and inputs received from experts. The suitability of areas have been evaluated on the basis of these criteria. There are substantial uncertainties and subjectivity about site information. Therefore F-PROMETHEE method is preferred. The case study shows that this application provides reasonable results. First Published Online: 16 Dec 2014

Document type: Article

Dynamic Analyses of Urban Expressway Network with Mesoscopic Traffic Flow Model Integrated Variable Speed Limits

Scipedia content — Fri, 12 Feb 2021 14:59:18 +0100

Urban congestion is a major and costly problem in many cities both in China and other countries. The purpose of building urban expressway is to alleviate the growing traffic pressure. In this paper, the mesoscopic traffic flow models are improved by variable speed limits strategy for the dynamic of vehicles on urban expressway network. The models include static queuing model, the velocity model, and the movement model of the vehicle. Moreover the method of the simulation is also proposed. So that we can get the corresponding variable speed limits values and aid traffic managers in making decisions to develop a network traffic flow control strategy. In the end, the elevated expressway of Jinan city is used as a simulation example. We investigated the performance of the transport system with averaged density, speed, and flow on link. We also analysed the dynamic of the traffic system on expressway network at different demand levels. The simulation results show that the models are feasible and effective and the variable speed limits strategy can successfully alleviate the traffic congestion in some extent. The operational efficiency of the transportation system is greatly improved.

Document type: Article

PROPOSTA DE UM INDICADOR DE CAPACIDADE DE ABSORÇÃO DO CONHECIMENTO (ICAC-COL): EVIDÊNCIA EMPÍRICA PARA O SETOR SERVIÇOS NA COLÔMBIA

Scipedia content — Fri, 12 Feb 2021 14:56:14 +0100

La "capacidad de absorción" es una capacidad dinámica reconocida por desarrollar habilidades de aprendizaje y explotación del conocimiento externo. Esta investigación propuso un Indicador de Capacidad de Absorción para Colombia denominado (ICAC-Col), utilizando los datos de la Encuesta de Desarrollo e Innovación Tecnológica realizada en Colombia, EDITS III para el sector servicios. Los resultados arrojan un nivel insuficiente de capacidad de absorción del conocimiento en el sector servicios, resaltando los sectores de transporte aéreo y servicios de gestión ambiental por poseer mayores capacidades para administrar el conocimiento, reflejando la necesidad de políticas públicas que impulsen actividades de gestión del conocimiento. "Absorption capacity" is a recognized dynamic capability because it develops learning skills and external knowledge exploitation. This research proposed an Absorption Capacity Indicator for Colombia called (ICAC-Col), using data from the Technological Innovation and development survey made in Colombia, EDITS III for services sector. The results show an insufficient level of knowledge absorption capacity in the services sector, however highlighting air transport sector and environmental management services because these have a greater ability to manage knowledge, reflecting the need for public policies to promote knowledge management activities. A "capacidade de absorção" é uma capacidade dinâmica reconhecida por desenvolver habilidades de aprendizagem e exploração do conhecimento externo. Esta pesquisa propôs um Indicador de Capacidade de absorção para Colômbia denominado (ICAC-CoL), utilizando os dados da enquete de Desenvolvimento e Inovação Tecnológica realizada na Colômbia, EDITs III para o setor serviços. Os resultados apresentam um nível insuficiente de capacidade de absorção do conhecimento em setor serviços, ressaltando os setores de transporte aéreo e serviços de gestão ambiental por possuir maiores capacidades para administrar o conhecimento, refletindo a necessidade de políticas públicas que impulsionem atividades de gestão do conhecimento.

Document type: Article

Fully Distributed Monitoring Architecture Supporting Multiple Trackeesand Trackers in Indoor Mobile Asset Management Application

Scipedia content — Fri, 12 Feb 2021 14:47:22 +0100

tracking service like asset management is essential in a dynamic hospital environment consisting of numerous mobile assets (e. g., wheelchairs or infusion pumps) that are continuously relocated throughout a hospital. The tracking service is accomplished based on the key technologies of an indoor location-based service (LBS), such as locating and monitoring multiple mobile targets inside a building in real time. An indoor LBS such as a tracking service entails numerous resource lookups being requested concurrently and frequently from several locations, as well as a network infrastructure requiring support for high scalability in indoor environments. A traditional centralized architecture needs to maintain a geographic map of the entire building or complex in its central server, which can cause low scalability and traffic congestion. This paper presents a self-organizing and fully distributed indoor mobile asset management (MAM) platform, and proposes an architecture for multiple trackees (such as mobile assets) and trackers based on the proposed distributed platform in real time. In order to verify the suggested platform, scalability performance according to increases in the number of concurrent lookups was evaluated in a real test bed. Tracking latency and traffic load ratio in the proposed tracking architecture was also evaluated.

Document type: Article

Policy Incentives for the Adoption of Electric Vehicles across Countries

Scipedia content — Fri, 12 Feb 2021 14:41:07 +0100

Electric vehicles (EVs) have prominent advantages for reducing CO 2 emissions and alleviating the dependence on fossil fuel consumption in the transport sector. Therefore, many countries have set targets for EV development in recent years and have employed a number of policies to achieve environmental objectives and alleviate the energy pressure. Despite the fact that the adoption of EVs has increased in the past few years, more policies, such as financial incentives, technology support or charging infrastructure, should be made by governments to promote broader range use of EVs. In this paper, we review the relevant policies that different countries may adopt for stimulating the market of EVs. Based on this, we analyze the relationship between the policies and the adoption of EVs by taking America as an example. In conclusion, some effective policies are summarized to spur the market. Therefore, each country should learn from each other and employ effective policies based on the actual situation.

Document type: Article

ElPrep: high-performance preparation of sequence alignment/map files for variant calling

Scipedia content — Fri, 12 Feb 2021 14:05:56 +0100

Prep is a high-performance tool for preparing sequence alignment/map files for variant calling in sequencing pipelines. It can be used as a replacement for SAMtools and Picard for preparation steps such as filtering, sorting, marking duplicates, reordering contigs, and so on, while producing identical results. What sets elPrep apart is its software architecture that allows executing preparation pipelines by making only a single pass through the data, no matter how many preparation steps are used in the pipeline. elPrep is designed as a multithreaded application that runs entirely in memory, avoids repeated file I/O, and merges the computation of several preparation steps to significantly speed up the execution time. For example, for a preparation pipeline of five steps on a whole-exome BAM file (NA12878), we reduce the execution time from about 1: 40 hours, when using a combination of SAMtools and Picard, to about 15 minutes when using elPrep, while utilising the same server resources, here 48 threads and 23GB of RAM. For the same pipeline on whole-genome data (NA12878), elPrep reduces the runtime from 24 hours to less than 5 hours. As a typical clinical study may contain sequencing data for hundreds of patients, elPrep can remove several hundreds of hours of computing time, and thus substantially reduce analysis time and cost.

Document type: Article

Understanding supply chain management concepts in the context of port logistics: an explanatory framework

Scipedia content — Fri, 12 Feb 2021 14:03:03 +0100

Copyright © 2014 Vilnius Gediminas Technical University (VGTU) Press. In academia as in practice, seaports are increasingly viewed as elements in supply chains. It is argued that seaports should add value to shippers by aligning their own business activities with shippers Supply Chain Management (SCM) strategies and requirements. The implications of this port-SCM philosophy are not fully explored, however. In this context, it is especially important to create mutual understanding between shippers, in terms of their SCM strategies, and port actors, in terms of services provided. In this paper a framework is developed, which aims to improve mutual understanding between shippers and port actors from a SCM point of view. It thereby aims to contribute to the dialogue on how the port logistics system can be better integrated into shippers SCM strategies. Three SCM reference models are analysed and twelve SCM subsystems identified that represent broad design areas of shippers SCM strategies. Further, the seaport system is discussed in terms of system boundaries and the actors involved. Port actors and SCM subsystems are then combined into one explanatory framework, the SCM-port actor matrix. Finally, applying the matrix, three cases retrieved from academic and trade literature in which port actors are actively involved in conducting shippers supply chain strategies are discussed. The paper concludes with a brief outlook on future research needs. 2014

Document type: Article

Detection of Legionella, L. pneumophila and Mycobacterium Avium Complex (MAC) along Potable Water Distribution Pipelines

Scipedia content — Fri, 12 Feb 2021 13:52:32 +0100

Inhalation of potable water presents a potential route of exposure to opportunistic pathogens and hence warrants significant public health concern. This study used qPCR to detect opportunistic pathogens Legionella spp., L. pneumophila and MAC at multiple points along two potable water distribution pipelines. One used chlorine disinfection and the other chloramine disinfection. Samples were collected four times over the year to provide seasonal variation and the chlorine or chloramine residual was measured during collection. Legionella spp., L. pneumophila and MAC were detected in both distribution systems throughout the year and were all detected at a maximum concentration of 103 copies/mL in the chlorine disinfected system and 106, 103 and 104 copies/mL respectively in the chloramine disinfected system. The concentrations of these opportunistic pathogens were primarily controlled throughout the distribution network through the maintenance of disinfection residuals. At a dead-end and when the disinfection residual was not maintained significant (p <

0.05) increases in concentration were observed when compared to the concentration measured closest to the processing plant in the same pipeline and sampling period. Total coliforms were not present in any water sample collected. This study demonstrates the ability of Legionella spp., L. pneumophila and MAC to survive the potable water disinfection process and highlights the need for greater measures to control these organisms along the distribution pipeline and at point of use.

Document type: Article

Real-time urban traffic amount prediction models for dynamic route guidance systems

Scipedia content — Fri, 12 Feb 2021 13:49:43 +0100

The route guidance system (RGS) has been considered an important technology to mitigate urban traffic congestion. However, existing RGSs provide only route guidance after congestion happens. This reactive strategy imposes a strong limitation on the potential contribution of current RGS to the performance improvement of a traffic network. Thus, a proactive RGS based on congestion prediction is considered essential to improve the effectiveness of RGS. The problem of congestion prediction is translated into traffic amount (i.e. the number of vehicles on the individual roads) prediction, as the latter is a straightforward indicator of the former. We thereby propose two urban traffic prediction models using different modeling approaches. Model-1 is based on the traffic flow propagation in the network, while Model-2 is based on the time-varied spare flow capacity on the concerned road links. These two models are then applied to construct a centralized proactive RGS. Evaluation results show that (1) both of the proposed models reduce the prediction error up to 52% and 30% in the best cases compared to the existing Shift Model, (2) providing proactive route guidance helps reduce average travel time by up to 70% compared to providing reactive one and (3) non-rerouted vehicles could benefit more from route guidance than rerouted vehicles do.

Document type: Article

The environmental effects of changing speed limits: a quantile regression approach

Scipedia content — Fri, 12 Feb 2021 13:32:49 +0100

Two speed management policies were implemented in the metropolitan area of Barcelona aimed at reducing air pollution concentration levels. In 2008, the maximum speed limit was reduced to 80 km/h and, in 2009, a variable speed system was introduced on some metropolitan motorways. This paper evaluates whether such policies have been successful in promoting cleaner air, not only in terms of average pollutant levels but also during high and low pollution episodes. To do so, we use a quantile regression approach for fixed effect panel data, which allows us analyzing different scenarios (beyond the average levels). We find that the variable speed system improves air quality with regard to the two pollutants considered here, being most effective when nitrogen oxide levels are not too low and when particulate matter concentrations are below extremely high levels. However, reducing the maximum speed limit from 120/100 km/h to 80 km/h has no effect - or even a slightly increasing effect - on the two pollutants, depending on the pollution scenario.

Document type: Article

Advances in consumer electric vehicle adoption research: A review and research agenda

Scipedia content — Fri, 12 Feb 2021 13:11:50 +0100

In spite of the purported positive environmental consequences of electrifying the light duty vehicle fleet, the number of electric vehicles (EVs) in use is still insignificant. One reason for the modest adoption figures is that the mass acceptance of EVs to a large extent is reliant on consumers’ perception of EVs. This paper presents a comprehensive overview of the drivers for and barriers against consumer adoption of plug-in EVs, as well as an overview of the theoretical perspectives that have been utilized for understanding consumer intentions and adoption behavior towards EVs. In addition, we identify gaps and limitations in existing research and suggest areas in which future research would be able to contribute.

Document type: Article

A Tree-Based Model for Setting Optimal Train Fare Zones

Scipedia content — Fri, 12 Feb 2021 13:00:43 +0100

Given a railway line with n stops and the number of travelers between each pair of stops, we show how to split these stops into k different fare zones in order to maximize the benefit obtained from the sale of tickets to the travelers. We present a method to obtain this solution that is based on finding the longest path in a weighted root tree. This method improves in terms of efficiency the combinatorial method, where all the possible distributions have to be considered for deciding which is the optimal one. The authors would like to thank RENFE for his collaboration and providing us several tables of data of the flow of passengers of the commuter trains of the Valencia region. J. Alberto Conejero is supported by MEC Project MTM2013-47093-P and Esther Sanabria-Codesal is supported by MEC Project MTM2012-33073. Conejero Casares, JA.; Jordan Lluch, C.; Sanabria Codesal, E. (2014). A tree-based model for setting optimal train fare zones. Mathematical Problems in Engineering. 2014:1-11. doi:10.1155/2014/384321 S 1 11 2014

Document type: Article

Design of the New Arch Bridge at Mioveni

Scipedia content — Fri, 12 Feb 2021 12:56:30 +0100

Road bridges with steel arches are used efficiently for medium and large spans. These solutions show advantages determined by the arches geometry, by the number and distributions of hangers and by the form and type of the arches bracing system. "/jats:p""jats:p"The appearance of the welding as standard connection procedure for steel bridges, for road bridge decks two solutions are mainly used: "/jats:p""jats:p"- the solution with a concrete slab acting together with the stringers and cross beams (the composite solution); "/jats:p""jats:p"- the solution with orthotropic deck (the orthotropic deck consists in a network formed by the continuous longitudinal stiffeners and cross beams connected at the upper part by a steel plate). "/jats:p""jats:p"In this paper a comparative study of the strength and fatigue checks performed on the new road bridge over river Argeşel near Mioveni in Argeş county is presented. The results are obtained using the Romanian standards STAS 1844-75 and SR 1911-1998 and the European norms SR EN 1990, SR EN 1993 and SR EN 1994. The deck was designed with two parallel steel arches, which are sustaining through vertical hangers a concrete slab connected with steel girders at the way level. "/jats:p""jats:p"The aim of the paper is to outcome the safety factors obtained from checks performed on steel hangers using the Romanian standards with respect with those obtained using Eurocodes.

Document type: Article

Public Transport Service Provisions and Policy Implications for Columbarium Trips

Scipedia content — Fri, 12 Feb 2021 12:49:08 +0100

BSTRACT Grave-sweeping is one of the popular special events in Asian cities, especially in Chinese societies, in which families express filial piety to their ancestors during two traditional grave-sweeping festivals in a year. The extraordinary high travel demand is often attracted to columbaria within a relative short period around the festivals, and induces severe impacts to the local traffic. It is challenging for the government and private operators to formulate a public transport service setting to satisfactorily cater all the visitors' travel demand. This paper aims to propose an optimization framework to identify the optimal provisions of public transport services for columbarium trips to achieve consumer surplus or profit maximization. Numerical studies are carried out using the travel demand data collected from a selected columbarium, to examine the effects of different public transport service settings to the policy objectives in various cases. The model results show that the current situation is neither consumer surplus nor profit optimum. Improvement schemes are suggested in relation to allow various fares during different visit periods and provide multiple public transport feeder services to serve the visitors during the high travel demand period.

Document type: Article

Bee Colony Optimization - part II: The application survey

Scipedia content — Fri, 12 Feb 2021 12:46:32 +0100

Bee Colony Optimization (BCO) is a meta-heuristic method based on foraging habits of honeybees. This technique was motivated by the analogy found between the natural behavior of bees searching for food and the behavior of optimization algorithms searching for an optimum in combinatorial optimization problems. BCO has been successfully applied to various hard combinatorial optimization problems, mostly in transportation, location and scheduling fields. There are some applications in the continuous optimization field that have appeared recently. The main purpose of this paper is to introduce the scientific community more closely with BCO by summarizing its existing successful applications. [Projekat Ministarstva nauke Republike Srbije, br. OI174010, OI174033, TR36002]

Document type: Article

City-HUB D4.1

Scipedia content — Thu, 11 Feb 2021 18:05:40 +0100

The focus of Work Package 4 is on the integrated management of interchanges. Based on case studies, stakeholder interviews, and literature, this work package analysed the organisation and operation of interchanges in terms of planning, operational functionality, management, practicalities, services and efficiency."br/"The research has shown that currently there are few examples of regulations or guidance that cover the design, construction, management and operation of interchanges as a whole. The interchange facility itself and the interchange zone are often considered to be ‘grey areas’ in transport planning; and the roles and responsibilities of those interested in the interchange are often dominated by the regulations of each mode. The design, construction and management of interchanges would benefit from closer interaction between the public and private sectors as there are opportunities for commercially successful utilisation of the space available in the terminals for services provided by the private sector, and thus make the interchanges economically more viable. In addition, partnerships with private sector can introduce business models which can complement the skills of the public sector. Public consultation should be carried out for the integration of the opinions and concerns of relevant stakeholders in the decision-making process in order to make the process more transparent, to gather more input on which to base decisions, and to create support for the decisions that are made. The positive impacts of an interchange on local economy are more likely to occur if there is an integrated development plan linking the transport function with the urban and economic functions. However, as the interchanges are typically located in the town centre, it is difficult to assess whether new developments in retail, housing or offices were direct results of the interchanges or if they would have been developed within town centre development context anyway."br/"Clear information systems are essential for making a public transport journey easy, efficient and stress-free. It is proposed that information between different operators and modes should be integrated to provide relevant information to all in a centralised and harmonised manner. Integrated, smart ticketing makes transferring easier for the traveller and thus promotes the use of public transport. It is a matter that needs to be addressed by the regional authorities and all stakeholders. Sustainable interchange design and energy efficiency are not only relevant for environmental purposes, but can also have positive impact on both social and economic elements. None of the present rating systems to assess energy efficiency are specifically developed for terminals or interchanges, but many of the tools can be applied successfully. For the end user, i.e. the traveller, however, the main point is neither the energy efficiency nor the carbon footprint of the interchange, but the functionality of the interchange for her/his needs, good air quality and comfortable atmosphere, and appropriate services."br

Urban Policies on Diversity in Copenhagen, Denmark

Scipedia content — Thu, 11 Feb 2021 17:56:59 +0100

Critical analysis of existing urban policy programmes and discourses in Copenhagen, Denmark. Includes overview of political systems and governance structures, key shifts in national discourses, and approaches to policy over migration, citizenship, and diversity.

Public Financial Institutions and the Low-carbon Transition

Scipedia content — Thu, 11 Feb 2021 14:35:11 +0100

Public financial institutions (PFIs) are well-positioned to act as a key leverage point for governments’ efforts to mobilise private investment in low-carbon projects and infrastructure. The study identifies the tools, instruments and approaches used by five PFIs to directly support and scale-up domestic private sector investment in sustainable transport, energy-efficiency and renewable energy in OECD countries. Between 2010-2012, these five institutions – Group Caisse des Depots in France, KfW Bankengruppe in Germany, the UK Green Investment Bank, the European Investment Bank, and the European Bank for Reconstruction and Development – have provided over 100 billion euros of equity investment and financing for energy efficiency, renewable energy and sustainable transport projects. They use both traditional and innovative approaches to link low-carbon projects with finance through enhancing access to capital; facilitating risk reduction and sharing; improving the capacity of market actors; and shaping broader market practices and conditions. Les institutions financieres publiques (IFP) sont particulierement bien placees pour completer les efforts des pouvoirs publics visant a mobiliser les investissements prives dans des projets et des infrastructures sobres en carbone. Cette etude identifie les outils, instruments et methodes dont se servent cinq IFP pour financer et / ou accroitre les investissements du secteur prive au niveau national dans les transports durables, l’efficacite energetique et l’energie renouvelable dans des pays membres de l’OCDE. De 2010 a 2012, ces cinq institutions – le Groupe Caisse des Depots en France, la KfW Bankengruppe en Allemagne, l’UK Green Investment Bank, la Banque europeenne d’investissement, et la Banque europeenne pour la reconstruction et le developpement – ont apporte un total de plus de 100 milliards EUR d’investissements en fonds propres et de financement en faveur de projets d’efficacite energetique, d’energies renouvelables et de transports durables. Elles font appel a des methodes a la fois traditionnelles et nouvelles pour lier des projets aux moyens de financement, en ameliorant l’acces aux capitaux ; en facilitant la reduction et le partage des risques ; en renforcant les capacites des acteurs de marche et, dans un cadre plus large, en mettant en place des pratiques et des conditions de marche.

Αεροπορικές εταιρείες χαμηλού κόστους & τουρισμός

Scipedia content — Wed, 10 Feb 2021 09:18:59 +0100

Βέλτιστος έλεγχος φωτεινής σηματοδότησης μέσω τετραγωνικού προγραμματισμού

Scipedia content — Wed, 10 Feb 2021 09:18:45 +0100

Electricity load estimation and management for plug-in vehicle recharging on a national scale prior to the development of third party monitoring and control mechanisms

Scipedia content — Wed, 10 Feb 2021 09:16:54 +0100

In accordance with the main aim of the study, a widely accessible, modifiable tool was created for parties interested in maintaining the national electricity supply network and parties interested in informing policy on plug-in vehicle adoption schemes and recharging behaviour control. The Parry Tool enables the user to incorporate present limits to plug-in vehicle recharging demand scheduling as imposed by the state of present technology (no third party mechanism for monitoring and control of recharging), present human travel behaviour needs and existing patterns in electricity usage; into the investigation of the impacts of recharging demand impacts and the design of mitigation measures for deflecting (parrying) worst case scenarios."br/"The second aim of the project was to demonstrate the application of the Parry Tool. The multidisciplinary/interdisciplinary information gathered by the Parry Tool was used to produce national demand profiles for plug-in vehicle recharging demand, calculated using socioeconomic and travel behaviour-estimated population sizes for plug-in eligible vehicles and vehicle usage patterns, which were added to existing national electricity demand for a chosen test week – this was the first scenario subsequently tested. The information gathered by the Parry Tool was then used to inform the design of two demand management methods for plug-in vehicle recharging: Recharging Regimes and weekly recharging load-shifting – these were the second and third scenarios subsequently tested."br/"Unmitigated simultaneous recharging demand in scenario 1 (all vehicles assumed to recharge at home upon arrival home every day) severely exacerbated peak demand, raising it by 20% above the highest peak in existing demand for the year 2009 over half an hour from 58,554 MW to 70,012 MW – a challenge to the generation sector. This increased the difference between daily demand minima and maxima and made the new total demand have sharper peaks – a challenge for grid regulators."br/"Recharging Regimes in scenario 2 split the estimated national plug-in vehicle populations into groups of different sizes that started recharging at different times of the day, with the word ‘regime’ being applied because the spread of start times changed over the course of the test week from workdays to weekend. This avoided exacerbation of the peak and reduced the difference between daily demand minima and maxima by raising minima, providing a load-levelling service. Scenario 3 embellished the Recharging Regimes with workday-to-weekend recharging load-shifting that therefore took better advantage of the often overlooked weekly pattern in existing demand (demand being higher on workdays than weekends), by allowing partial recharging of a segment of the plug-in vehicle population."br/"Limited consideration of the impact of changing vehicle energy usage (for which distance travelled was assumed to proxy in this study) showed that the more vehicles used their batteries during the day, the better the levelling effect offered by Recharging Regimes. Greater utilisation of battery capacity each day, however, can also be assumed to lessen the potential for workday-to-weekend load levelling, because load-shifting depends upon vehicles being able to partially recharge or defer recharging to later days and still meet their travel needs plus keep a reserve State Of Charge (SOC) for emergency and other unplanned travel. Whilst altering vehicle energy usage did not change the finding that unmitigated simultaneous recharging exacerbated existing peak demand, it was noted that when limited mileage variation was considered this sharpened the profile of total demand – the rise and fall of the new peak far steeper than that of the original peak in existing demand."br/"The Parry Tool combines a series of integrated methods, several of which are new contributions to the field that use UK data archives but may potentially be adapted by researchers looking at energy issues in other nations. It presents a novel fossil-fuel based justification for targeting road transport – acknowledging energy use of fossil fuel as the originator of many global and local problems, the importance of non-energy use of petroleum products and subsequent conflicts of interest for use, and a fossil fuel dependency based well-to-wheel assessment for UK road transport for the two energy pathways: electricity and petroleum products. It presents a method for the recalculation and ranking of top energy use/users using national energy use statistics that better highlights the importance of the electricity industry. It also presents the first publicly documented method for the direct consultation and extraction of vehicle-focused statistics from the people-focused National Travel Survey database, including a travel behaviour and household income-based assessment of plug-in vehicle eligibility, used to scale up to national estimates for battery electric and plug-in electric hybrid vehicle (BEV and PHEV) national population sizes."br/"The work presented here is meant to allow the reader to perceive the potential benefits of using several resources in combination. It details the Parry Tool, a framework for doing so, and where necessary provides methods for data analysis to suit. It should however be noted that methods were kept as simple as possible so as to be easily followed by non-specialists and researchers entering the field from other disciplines. Methods are also predominantly data-exploratory in nature: strong conclusions therefore should not be drawn. Rather, the work here should be seen as a guideline for future work that may more rigorously study these combined topics and the impacts they may have upon plug-in vehicle ownership, usage behaviour, impacts of recharging upon the national network and the design of mitigation measures to cope with this new demand.

Cross-sectional shape effects on resistance to uniform flow in open channels and non-circular closed circuits

Scipedia content — Tue, 09 Feb 2021 09:25:06 +0100

Εφαρμογή έμπειρων τεχνικών και συστημάτων στο βέλτιστο σχεδιασμό δρομολογίων οχημάτων στόλου διανομής

Scipedia content — Tue, 09 Feb 2021 09:23:29 +0100

Decision making in air traffic control units and team performance in emergency scenarios

Scipedia content — Tue, 09 Feb 2021 09:20:58 +0100

Βέλτιστος έλεγχος φωτεινής σηματοδότησης μέσω τετραγωνικού προγραμματισμού

Scipedia content — Tue, 09 Feb 2021 09:00:37 +0100

Παρακολούθηση ψυχοσωματικής κατάστασης οδηγού με χρήση βιοσημάτων

Scipedia content — Tue, 09 Feb 2021 09:00:26 +0100

Electricity load estimation and management for plug-in vehicle recharging on a national scale prior to the development of third party monitoring and control mechanisms

Scipedia content — Tue, 09 Feb 2021 08:55:59 +0100

Decision making in air traffic control units and team performance in emergency scenarios

Scipedia content — Tue, 09 Feb 2021 08:54:15 +0100

Analysis of the dynamic behaviour of squat silos containing grain-like material subjected to shaking table tests—ASESGRAM final report

Scipedia content — Mon, 08 Feb 2021 12:32:51 +0100

This paper reports the outcomes of a series of shaking table tests performed at the EQUALS lab of Bristol University in the framework of the project entitled “ASESGRAM”, carried out within the Transnational Access Activities of the SERIES Project. The experimental test campaign was devoted to the evaluation of the effective behaviour of flat-bottom silos filled with grain under dynamic excitation, and to the experimental verification of the results obtained in previous analytical research work by the authors (Silvestri et al., Bull Earthq Eng 10:1535–1560, 2012). This analytical counterpart starts from the basic assumptions of Eurocode 8 (EN 1998–4, Eurocode 8. Design of structures for earthquake resistance, Part 4: silos, tanks and pipelines, CEN, 2006) excluding the calculation of horizontal shear forces among consecutive grains. This difference leads to a new physically-based evaluation of the effective mass of the grain, which horizontally pushes on the silo walls. The analyses are developed by simulating the earthquake ground motion with time constant vertical and horizontal accelerations and are carried out by means of simple dynamic equilibrium equations that take into consideration the specific mutual actions developed in the ensiled grain. The findings indicate that in case of squat silos (characterized by low, but usual, height/diameter slenderness ratios), the portion of the grain mass that interacts with the silo walls turns out to be noticeably lower than the total mass of the grain in the silo and the effective mass adopted by Eurocode 8 (EN 1998–4, Eurocode 8. Design of structures for earthquake resistance, Part 4: silos, tanks and pipelines, CEN, 2006). Different series of tests have been performed with different heights of the ensiled material to simulate a more or less squat silo. In the tests, the ensiled material consisted of Ballotini Glass. In this paper, the silo specimen and the test instrumentation are described, and the test program and the results are presented. Strong qualitative indications are obtained, which basically confirm that the wall-grain friction coefficient plays an important role in the actions at the base of the silo walls.

Field Operational Tests and deployment plans

Scipedia content — Mon, 08 Feb 2021 12:32:02 +0100

In this chapter an explanation is given of Field Operational Tests (FOT), studies to evaluate the impact of Intelligent Transport Systems (ITS) in the real world. The methodology for designing and conducting these tests is described. Different types of FOT can be distinguished, testing advanced driver assistance systems and nomadic devices, as well as cooperative systems allowing communication between vehicles and between vehicles and infrastructure. This last type of test is discussed in more detail, addressing the question of how they can be used for testing vehicular ad hoc network (VANET) technologies, and examples are given of both European and US projects. Specifically the DRIVE C2X project is described, as it explicitly addresses these technologies. Conducting FOTs is an important step on the way to the deployment of ITS. Also, data deriving from these studies can be deployed, in new projects, to answer new research questions. The chapter concludes with a description of the networking and community building activities in the Field Operational Test domain.

Logistics and Supply Chain Innovation

Scipedia content — Mon, 08 Feb 2021 12:31:01 +0100

This contributed volume presents state-of-the-art advances in logistics theory in various fields as well as case studies. The book reports on a number of recently conducted studies in the Dinalog and the Effizienz Cluster Logistik Ruhr, thus bridging the gap between different perspectives of theoretical and applied research. A selection of theoretical topics, practical examples, case studies and project reports is presented in this volume. The editors carefully selected contributions from a wide variety of projects, which were carried out in both the Dinalog cluster and the Effizienzcluster Logistik Ruhr. The contributions are grouped in five main sections, each representing key domains in the evolution of logistics and supply chain management: sustainability, urban logistics, value chain management, IT-based innovation, knowledge management. This book is intended for both researchers and practitioners in the field of logistics and supply chain management, to serve as an important source of information for further research as well as to stimulate further innovation.

The missing link

Scipedia content — Mon, 08 Feb 2021 12:29:05 +0100

Viruses have gained a notoriously bad reputation as infectious agents, but they are nonetheless fascinating for biologists, not least because they are the most numerous and fastest evolving organisms on the planet. Moreover, viruses have had a significant role in the evolution of all other organisms, from bacteria through vertebrates to humans. But the full extent of this role is only just emerging, and scientists are reappraising not just the relationship between viruses and their hosts, but also the main principle of evolution: that it operates largely on the basis of gene mutation coupled with selection. " …viruses have had a significant role in the evolution of all other organisms, from bacteria through vertebrates to humans In fact, infectivity is only the tip of the viral iceberg, and cohabitation is actually the norm—as is the case for bacteria. Similarly to bacteria and other microorganisms, most viruses and their hosts have co‐evolved either into commensal relationships where the parasite's impact is neutral, or into mutually beneficial symbiotic arrangements. Of course, for viruses there is also the additional genomic dimension: they insert themselves into the host's DNA and in doing so can generate novel proteins and RNA molecules that might be valuable to the host. Moreover, it also allows the virus to manipulate the host genomic structure itself. Although this ability could wreak potential genetic havoc, it might also trigger significant structural and functional changes in the host genome that could not occur through random mutation alone. Viruses have the unique ability to incorporate themselves permanently into the genomes of their hosts—a phenomenon known as endogenization—and thus lose their ability to infect other individuals. In return, they gain immortality, as they are passed down to successive generations of hosts. Yet, although no other microorganisms can invade the genome, endogenization has a parallel among …

Reactivation of the Small Inland Waterway Network

Scipedia content — Mon, 08 Feb 2021 12:13:50 +0100

Inland shipping in North Western Europe is a well known transportation mode which can make use of a large and dense inland waterway network. However in the last 50 years no new small inland ships have been built. The reasons why these small inland ships are disappearing are explained. In order to deal with the diminished supply on the small inland waterways a new type of inland navigation system is proposed. A methodology is developed to research this new inland navigation system. In the developed methodology a network design, tug and barge design, transportation costs and competition models are combined into a single model. The main goal of the total model is to determine the profitability, expressed in the Net Present Value (NPV), of the investment in a specific ship and network design. Also the link between transport function of waterway and the actual design of the waterway network is made. Lastly the role of the government is discussed in how it could facilitate the reactivation of the small inland waterway network.

City Logistics by Water: Good Practices and Scope for Expansion

Scipedia content — Mon, 08 Feb 2021 12:12:57 +0100

Urban freight transport became a specific research topic as the general awareness on the increasing negative effects of these freight delivery activities on the local livability grows. The awareness for external costs (congestion, emissions, noise and road safety) by the public grew. As a result, (local) governments implemented specific policies. Often, these limit the free, flow of traffic, put limits on (un)loading activities and limit urban road capacity. As a result, logistics entrepreneurs innovate their last mile transport operations. An under-investigated opportunity is the use of waterways for urban freight delivery purposes. This chapter lists best practices found in Western Europe. These transport freight towards or in the city. In this chapter, a Dutch concept was translated into a specific case for the Belgian city of Ghent. A cost simulation of an urban delivery concept with an electrically-powered vessel is developed and gives us insight in the actual competitiveness. Based on our own simulation, conclusions are drawn. Further research opportunities are indicated.

Interreg elektrisch rijden

Scipedia content — Mon, 08 Feb 2021 10:23:38 +0100

Titel: Technologie Scan Elektrische Mobilität Korte presentatie in het Duits over elektrisch rijden. De presentatie is gehouden bij Interreg op 17 september 2014.

Dynamic control system for electric motor drive testing on the test bench

Scipedia content — Mon, 08 Feb 2021 10:21:09 +0100

Tailoring instruction-set extensions for an ultra-low power tightly-coupled cluster of OpenRISC cores

Scipedia content — Mon, 08 Feb 2021 10:14:49 +0100

Baseline RISC instruction sets for ultra-low power processors are constantly being tuned to reduce cycle count when executing computation-intensive applications. Performance improvements often come at a non-negligible price in terms of area and critical path length and imply deeper pipelines and complex memory interfaces. This penalizes control-intensive code execution and significantly increases cost and complexity of building multi-core clusters. In addition, some extensions are not easily exploited by compilers and may increase code development effort, especially when considering parallel applications. In this paper we describe our efforts in enhancing a baseline open ISA (OpenRISC) and its LLVM compiler back-end to significantly reduce execution cycles while minimizing the impact on core micro-architecture complexity, number of pipeline stages, area and power. In addition, we improved the core micro-architecture to streamline its integration in a tightly-coupled cluster, sharing instruction cache and data memory, thereby further enhancing parallel execution efficiency. The combined effect of ISA, compiler and micro-architecture evolution gives an average energy efficiency boost of 59% on vector intensive code and 41% otherwise, at an area and power increase of 2.3% and 18% on a four-core processor cluster.

A robust multiple PI controller for the air distribution into an arc heater

Scipedia content — Mon, 08 Feb 2021 10:12:23 +0100

This paper deals with the problem of controlling both the air total mass flow-rate and its distribution in a 70 MW electric arc heater by means of a five way air supply system. Firstly a description of the detailed dynamic model of the pneumatic process, obtained in the lumped parameter domain, is provided, then the proposed control strategy is described. In order to guarantee the desired distribution of the total air supplied along the arc heater, a multiple PI control technique is proposed to command five partitioning valves. A physical reduction of the process model allows us to reduce the control problem to the synthesis of five standard PI controllers for Linear Parameter Varying first order systems. A robust synthesis of the controller gains which makes use of the concept of quadratic stability with a fixed decay rate and with an H∞ norm bound is proposed to cope with uncertainties, nonlinearities and disturbances. Numerical simulations are carried out to show the effectiveness of the control technique. © 1999 EUCA.

Analysis of the Interaction Between Buried Pipelines and Slope Instability Phenomena

Scipedia content — Mon, 08 Feb 2021 10:06:27 +0100

Economic and social integration across Europe requires secure lifelines, such as roads, railways and pipelines. Existing and planned lifelines may come across a large number of different natural and anthropic hazards. For instance, past catastrophic events have dramatically shown that steel pipelines may be highly vulnerable to permanent ground deformation due to earthquakes and landslides. Therefore, their behaviour when exposed to processes that can generate large displacement and strain (co-seismic deformation and faulting, liquefaction, earth and rock slides and flows, rock falls) needs to be assessed. In fact, and in particular if toxic and/or flammable materials are transported, structural damage with eventual leakage might result in a severe risks for both human life and the environment, with associated relevant economic costs. To such purpose, in this work, a methodology for the assessment, prevention and efficient management of geological risks, mainly landslides, in steel buried pipelines will be presented. The proposed procedure aims at reducing the risk of environmental disasters and the subsequent huge financial and environmental losses.

Performance and Efficiency of High-speed Rail Systems

Scipedia content — Mon, 08 Feb 2021 10:04:43 +0100

In their search to optimize the utilization of high-speed rail systems governments and railway companies may benefit from good practices in the rest of the world. Benchmarking of these systems in operation may give guidance to best practices in this sector to learn from. This study was initiated as, to our knowledge, no objective comparison of high-speed rail systems is available. Based on the current knowledge and experience, Network Data Envelopment Analysis (NDEA) in combination with the Malmquist Productivity Index was chosen for the benchmark. Four Asian and four European high-speed rail systems are compared using the actual system characteristics and performance between 2007 and 2012. To investigate the production efficiency and service effectiveness of the high-speed railways under study, a performance matrix is introduced. This study identifies the most efficient high-speed rail systems and the contributing factors in achieving high performance in production and marketing. It reveals significant differences between Asia and Europe, but also within these regions remarkable differences are found.

Building a probabilistic grid-based road representation from direct and indirect visual cues

Scipedia content — Mon, 08 Feb 2021 10:01:44 +0100

Detecting the road terrain ahead of the ego-vehicle is an important issue for modern driver assistance systems. In particular, vehicle motion planning in inner city environment requires the detection of road terrain up to 3 seconds in advance. State-of-the-art visual road terrain detection systems have a hard time fulfilling this task, due to their limited range and the presence of occlusions (other vehicles, buildings, etc.), which are expected to occur often in complex scenarios. However, those systems provide significant information where the conditions are favorable (proximity to the ego-vehicle, no occlusions). Therefore, a complementary approach is needed to enhance already existing and established detection systems. In this paper we propose a probabilistic grid-based approach based on the observation and interpretation of other vehicles' behavior in the scene. It exploits their movements in order to infer the presence and location of occluded road surface. We will show that this approach presents various advantages over current visual road terrain detection systems, especially in those situations that are the most challenging for them. We will illustrate how our approach is designed to work in concert also with other available resources, e.g. offline road maps. Qualitative results on real-world scenes taken from the KITTI benchmark[11] demonstrate that the fusion of this method with visual road terrain detection can potentially extend our time horizon well over the 3 seconds mentioned above. Finally, we will show how our approach is planned to develop into a semantically enriched representation of the road, including road properties such as availability, lanes and directions.

Blockage Detection in Pipeline Networks for Gas and Oil

Scipedia content — Mon, 08 Feb 2021 09:59:38 +0100

This paper proposes a technique for the preliminary identification of pipes obstructed by blockages within a pipeline or a complex pipe network, relying only upon few measurements that are usually gathered to monitor the infrastructure operability. Blockages are identified as a result of an optimization procedure that minimizes the discrepancy between measured and simulated flow quantities. The framework exploits a Finite Element-like simulator of the flow problem in the system of pipes and Genetic Algorithms to perform the optimization procedure. Thermal properties of the fluid flowing inside the pipe system are considered. Results of the identification procedure are presented, and advantages and disadvantages of the procedure for the on-field implementation are outlined.

Experimental Investigation of Horizontal Gas-Liquid Stratified and Annular Flow Using Wire Mesh Sensor

Scipedia content — Mon, 08 Feb 2021 09:58:11 +0100

Stratified and annular gas–liquid flow patterns are commonly encountered in many industrial applications, such as oil and gas transportation pipelines, heat exchangers, and process equipment. The measurement and visualization of two-phase flow characteristics are of great importance as two-phase flows persist in many fluids engineering applications. A wire-mesh sensor (WMS) technique based on conductance measurements has been applied to investigate two-phase horizontal pipe flow. The horizontal flow test section consisting of a 76.2mm ID pipe, 18m long was employed to generate stratified and annular flow conditions. Two 16 16 wire configuration sensors, installed 17 m from the inlet of the test section, are used to determine the void fraction within the cross section of the pipe and determine interface velocities between the gas and liquid. These physical flow parameters were extracted using signal processing and cross-correlation techniques. In this work, the principle of WMS and the methodology of flow parameter extraction are described. From the obtained raw data time series of void fraction, cross-sectional mean void fraction, time averaged void fraction profiles, interfacial structures, and velocities of the periodic structures are determined for different liquid and gas superficial velocities that ranged from 0.03m/s to 0.2m/s and from 9m/s to 34m/s, respectively. The effects of liquid viscosity on the measured parameters have also been investigated using three different viscosities. [DOI: 10.1115/1.4027799]

Stochastic equilibrium assignment with variable demand: theoretical and implementation issues

Scipedia content — Mon, 08 Feb 2021 09:55:19 +0100

Recently, it has been pointed out that transport models should reflect all significant traveller choice behaviour. In particular, trip generation, trip distribution, modal split as well as route choice should be modelled in a consistent process based on the equilibrium between transport supply and travel demand. In this paper a general fixed-point approach that allows dealing with multi-user stochastic equilibrium assignment with variable demand is presented. The main focus was on investigating the effectiveness of internal and external approaches and of different algorithmic specifications based on the Method of Successive Averages within the internal approach. The vector demand function was assumed non-separable, non-symmetric cost functions were adopted and implementation issues, such updating step and convergence criterion, were investigated. In particular the aim was threefold: (i) compare the internal and the external approaches.; (ii) investigate the effectiveness of different algorithmic specifications to solve the variable demand equilibrium assignment problem through the internal approach; (iii) investigate the incidence of the number of the links with non-separable and/or asymmetrical cost functions. The proposed analyses were carried out with respect to two real-scale urban networks regarding medium-size urban contexts in Italy.

Combined generation of road marking and road sign databases applied to consistency checking of pedestrian crossings

Scipedia content — Mon, 08 Feb 2021 09:43:54 +0100

Combined road marking and traffic sign databases are beneficial for both road maintenance and for usage within navigation devices and autonomous driving vehicles. The combination of both markings and signs completely provides all instructions and legislation for drivers. This paper presents a conceptual system for the automated creation of such combined databases and investigates the benefit of this combination for the specific case of pedestrian crossings. Evaluations on 62 km of road have shown that individual detection of road signs and markings indicating pedestrian crossings is very accurate (≥ 95%), enabling selective safety analysis towards these specific locations. Combining both approaches enables very accurate identification of crosswalks and additionally leads to the retrieval of crossings with undetectable markings or signs, such that maintenance can be directed specifically towards these potentially dangerous crosswalks.

Optimization in Oil Pipelines Arrangement with Fermat Problem

Scipedia content — Wed, 03 Feb 2021 22:01:21 +0100

Cooperation versus competition towards an efficient parking assignment solution

Scipedia content — Wed, 03 Feb 2021 22:00:41 +0100

International audience; Cars cruising for parking adds a non negligible amount to traffic congestion and CO2 pollution. Hence, good parking management policies are required to reduce such discomfort. In this paper, we address this problem from two sides. First, we consider how local parking authorities called parking coordinators (PC) can optimize the distribution of the slots they manage through a full cooperation between them. Second, we model the problem as a congestion game, where vehicles act as players who will eventually choose the best parking garage for them, while minimizing the whole network cost. We study the effectiveness of both schemes (i.e, PC-aware and game theoretic approaches) in various contexts and compare them with the reference centralized model as well as a greedy approach. Simulation results show that our proposals provide high request satisfaction ratio, close to the optimal baseline approach and outperform the greedy method up to 30%, while ensuring a fair distribution of slots through the network.

Zonal Operations: a method to rationalise operations

Scipedia content — Wed, 03 Feb 2021 21:53:43 +0100

In August 2013 and for the third consecutive year, Melbourne has been accredited as the most liveable city in the world. However, the city is also known and credited for a less attractive reason as “The City of Level Crossings”; the city’s metropolitan area is home to 170 railroad level crossings (RLX). Since 2006, Melbourne has experienced unprecedented train patronage demand. Victorian transport authorities, facing capacity, demand and overcrowding problems, have acquired new train sets, established new timetables that introduced additional urban train services, and prepared long term plans to address the issue. However, the additional train services result in a ‘catch 22’ situation. The additional train traffic causes extra boom gate activity at railroad level crossings, which in turns leads to additional vehicles congestion on Melbourne’s roads. This research investigates and proposes the introduction of Zonal Operations (ZO) in the Caulfield Group corridor that includes some of Melbourne’s longest and busiest lines within the rail network. The research discusses the concept of ZO, analyses the claim that ZO resolves capacity and overcrowding problems, a claim proposed in research literature. In addition, this research confirms that ZO has the potential to reduce the number of times boom gates are lowered at RLXs, and to mitigate road traffic congestion at RLXs. By doing this, a better understanding is gained in how ZO in railways can be used to mitigate road traffic congestion issues at RLX locations.

On the transfer time complexity of cooperative vehicle routing

Scipedia content — Wed, 03 Feb 2021 21:42:33 +0100

Motivated by next-generation air transportation systems, this paper investigates the relationship between traffic volume and congestion in a multi-agent system, assuming that the agents can communicate their intentions with one another. In particular, we consider n independent mobile agents, each assigned an origin and a destination point, and study how the minimum time necessary to safely transfer all agents from their origin to their destination scales with the number of agents n. We provide an algorithm for which the transfer time scales logarithmically in n. This is an improvement over previous results that rely on more conservative conflict models because the agents do not leverage inter-agent cooperation to the same degree, resulting in transfer times that scale as √n.

High-Speed trains and tourists: what is the link ? Evidence from the French and Spanish capitals (article)

Scipedia content — Wed, 03 Feb 2021 21:31:47 +0100

International audience; The objective of this paper is to analyse the factors influencing tourists’ choice of a destination and the role of High Speed Rail (HSR) systems in this choice. The methodology proposed consists in analysing two capitals in Europe, i.e. Paris and Madrid where HSR services are important, to investigate the factors influencing holidaymakers in choosing these cities, and the role of HSR in this choice. The main outcome of this paper is to show that several factors influence the choice of a tourist, like the presence of architectural sites, the quality of promotion of the destination itself, the presence of events, and also HSR services. However we found that the HSR system has affected the choice of Paris and Madrid in a different way. Concerning the French case study, HSR is considered a real transport mode alternative among tourists, therefore HSR is chosen to reach Paris as well as for revisiting it. On the other hand, Madrid is chosen by tourists irrespective on the presence of HSR, while HSR is chosen for reaching cities close to Madrid. Data collected from the two surveys have been used for a further quantitative analysis. Models have been specified and calibrated to identify the factors influencing holidaymakers to revisit Paris and Madrid and the role of HSR in this choice has been highlighted.

Document type: Conference object

Modeling and Identification of the Restoring Force of a Marine Riser

Scipedia content — Wed, 03 Feb 2021 21:29:17 +0100

International audience; The purpose of this paper is to provide a novel model to characterize the nonlinear restoring force of a marine vertical riser by using position-and-velocity-dependent polynomials. This model permits the obtaining of a specific state space representation--via the Li'enard transformation--for the design of state observers that identify the structural parameters of vertical risers. The main results presented here are: (i) an approximation of the nonlinear restoring force by means of polynomials and its incorporation into a distributed parameter (DP) model, (ii) the transformation of the DP model into a Li'enard system and (iii) an analysis of its observability and identifiability properties.

Inattentional Deafness in Simulated Air Traffic Control Tasks : A Behavioral and P300 Analysis

Scipedia content — Wed, 03 Feb 2021 21:24:37 +0100

International audience; The acoustic environment is critical in Air Traffic Control (ATC), as operators exchange information with planes and must also be aware of the occurrence of auditory alarms. In such situations, observing inattentional deafness is likely. In this study, we aimed to identify the physiological indicators of inattentional deafness through the analysis of the P300 evoked potential, known to be an indicator of attention allocation, an important step to a stimulus reaching consciousness. Based on the assumption that the high mental load generated by an ATC task may reduce the alarm detection rate, we wished to test whether this effect would be reflected in the alarm-evoked P300 amplitude. Participants had to perform simulated ATC tasks within the LABY microworld while electroencephalographic (EEG) activity was recorded. Simultaneously to the LABY tasks, participants were asked to respond to target tones (the “alarm”) and to ignore standard tones. Behavioral results showed that 4.6% of alarms were not reported. For these alarm detection failures, the EEG analysis showed a diminution of the P300 amplitude in comparison to a control condition in which participants only focused on the tones. These results suggest that the P300 amplitude seems to be a valid physiological indicator of vulnerability to inattentional deafness in complex environments. Relevant applications include the prevention of alarm omission and the assessment of warning designs.

The Effects of Cultural Values and Habits on Bicycle Use-Konya Sample

Scipedia content — Wed, 03 Feb 2021 21:23:52 +0100

2nd World Conference on Psychology and Sociology (PSYSOC) -- NOV 27-29, 2013 -- Brussels, BELGIUM

WOS: 000345439900029

One of the primary factors causing an upheaval of environmental problems in cities is the consumption habits in transportation and the ever-creation of a demand for these habits. Consequently, the cultural values and habits need to be altered to enable a sustainable transportation planning. In our current day, policies need to be developed aimed at the improvement of bicycle utilization, being among the environmentally friendly modes of transportation, in order to reduce transportation-caused urban environmental problems. Therefore, the purpose of this study is to make people gain the habit of bicycle riding being one of the basic sources in the sustainable transportation in cities or the revitalization of habits on the verge of extinction. Konya city has been selected as the sampling field for the determination of the impact of the societal cultural values and habits on bicycle riding and for this aim, survey study and observations were made in this city. As a result of the assessment of this survey study, problems restricting bicycle riding and originating from cultural values and habits have been identified and suggestions have been developed aimed at resolving these issues. (C) 2014 The Authors. Published by Elsevier Ltd.

Finding Pulsars in Real-Time

Scipedia content — Wed, 03 Feb 2021 21:22:50 +0100

Finding new pulsars has always been a challenging problem, but this challenge is nowadays exacerbated by the increasing data rates of modern radio telescopes. Because of these increased data rates, traditional approaches to searching, based on storing data for off-line processing, are becoming unfeasible. Therefore, we propose a new pulsar searching pipeline that, by exploiting high-performance computing techniques, is able to process observational data in real-time. To achieve the real-time goal we parallelized all the steps of the pipeline to run on many-core accelerators, and used auto-tuning to adapt and optimize the pipeline for different platforms, telescopes, and searching parameters. In this paper, we test our pipeline on three different platforms: two Graphics Processing Units from AMD and NVIDIA, and an Intel Xeon Phi. Furthermore, we test it on three different scenarios, based on the operational parameters of three state-of-the-art telescopes. Results show that our pipeline can adapt to all tested platforms and scenarios, and achieves real-time performance and linear scalability. Because power consumption is a main concern for radio telescopes, and will be the main bottleneck for the construction of the Square Kilometer Array, we also measure the power consumed by our pipeline. By comparing the results obtained on many-core accelerators with the results obtained using a traditional multi-core CPU, we conclude that the accelerators can provide up to a factor 8 improvement in execution time, and up to a factor 6 reduction in power consumption.

On development strategy of rural logistics market

Scipedia content — Wed, 03 Feb 2021 21:20:49 +0100

Due to the particularity of agriculture and villages, rural logistics market is completely different from urban logistics market in terms of logistics demand and supply. This paper discusses main features of rural logistics market, analyzes the problems in China’s rural logistics market and proposes development strategy of China’s rural logistics market on the basis of summarizing rural logistics market.

Benefits Analysis of Multi-Center Dynamic Weather Routes

Scipedia content — Wed, 03 Feb 2021 21:20:38 +0100

Dynamic weather routes are flight plan corrections that can provide airborne flights more than user-specified minutes of flying-time savings, compared to their current flight plan. These routes are computed from the aircraft's current location to a flight plan fix downstream (within a predefined limit region), while avoiding forecasted convective weather regions. The Dynamic Weather Routes automation has been continuously running with live air traffic data for a field evaluation at the American Airlines Integrated Operations Center in Fort Worth, TX since July 31, 2012, where flights within the Fort Worth Air Route Traffic Control Center are evaluated for time savings. This paper extends the methodology to all Centers in United States and presents benefits analysis of Dynamic Weather Routes automation, if it was implemented in multiple airspace Centers individually and concurrently. The current computation of dynamic weather routes requires a limit rectangle so that a downstream capture fix can be selected, preventing very large route changes spanning several Centers. In this paper, first, a method of computing a limit polygon (as opposed to a rectangle used for Fort Worth Center) is described for each of the 20 Centers in the National Airspace System. The Future ATM Concepts Evaluation Tool, a nationwide simulation and analysis tool, is used for this purpose. After a comparison of results with the Center-based Dynamic Weather Routes automation in Fort Worth Center, results are presented for 11 Centers in the contiguous United States. These Centers are generally most impacted by convective weather. A breakdown of individual Center and airline savings is presented and the results indicate an overall average savings of about 10 minutes of flying time are obtained per flight.

In-line inspection of pipelines by using a smart Pig (ITION) and multivariate statistical analysis

Scipedia content — Wed, 03 Feb 2021 21:19:24 +0100

The ferrous pipe structures of oil and gas production and, the transmission pipelines are, in majority, buried. Nowadays, phenomena like corrosion, mechanical stress, soil erosion, worker mistakes and damages caused by third parts have generated several problems over pipelines. Thus, major investment on integrity programs with In-Line Inspection Tools has been improved in order to examine the pipelines and avoid environmental, financial and social disasters. Recently in Colombia, the Research Institute of Corrosion - CIC (Corporacion para la Investigacion de la Corrosion) runs their own smart pig ILI tool in pipelines. The inspection technology is based on inertial and operational trends, ITION (Inertial Technology Inspection and Operational Trends). Up to date, the technology has been tested several times inside of pipelines providing valuable information along of thousand kilometres. These records contain a huge amount of data that sometimes is difficult or impossible to understand by themselves. A univariate statistical analysis can be used to determine the thresholds for each observation variable. However, it does not analyse the correlated information between them. In this way, the main contribution of this work is the development of a methodology based on Principal Component Analysis (PCA) to monitor the structure by using the whole available variables gathered by ITION. doi: 10.12783/SHM2015/291

Document type: Conference object

Air Traffic Control Approach Procedural Separation Assessment Mode

Scipedia content — Wed, 03 Feb 2021 21:17:11 +0100

In recent yea rs, with the rapid increase of air traffic flow, fight conflict have become more and more serious. So it is very necessary to study mid-air collision. The purpose of the paper is to establish the mode of approach procedural separation assessment. The degree which approach separation is been affected by all the factors has been worked out. The distance at which the pilot may report to the ATC (air traffic controller )form the radio blind area center when the aircraft over flying the VOR/NDB and the number of the report at the distance is submit to normal distribution has been approved. The separations have been decided by using the probability and the mathematics methods. According to the relationship of each factor the component of the mode has been decided and the mode has been build up. The mode of approach procedural separation assessment has been tested and extended.

A Comparative Study of a Free Span Pipeline Through Numerical Simulations

Scipedia content — Wed, 03 Feb 2021 21:15:50 +0100

A subsea pipeline has an important role to produce oil and gas from an offshore petroleum field, connecting a petroleum facility at the open sea and a near shore terminal at the coast. Very often, the pipeline passes over areas with uneven seafloor, and it may present free span portions. The main aim of the present work is improvements on the understanding of undesirable effects of vibrations in a subsea pipeline which presents free span portions along its length. This understanding is fundamental for the safe design and operation of the pipeline with possible reduction of its fatigue life."/jats:p" "jats:p"Dynamic loads can occur as a consequence of the presence of sea currents acting on portions of the pipeline with free spans. Due to this hydrodynamic current loads, the pipeline structure may oscillate in the same direction of the current (In-line) and, in its transverse direction (Cross-Line). This dynamic response at the free span is mainly caused by the Vortex Induced Vibration (VIV). It is very important for the pipeline design because it can result extreme unacceptable stresses as well as in exceeding limits for the fatigue damage of the pipeline. And, this problem of VIV is still not been completely understood."/jats:p" "jats:p"In the present paper, different models to estimate VIV forces due to sea current are discussed. For this purpose, different computer programs were used to predict vibrations in the transverse direction of the current incidence direction, caused by the vortex shedding in a free span of the pipeline. Simulations of the dynamic behavior of a free span portion of the pipeline were carried out by two approaches, respectively: an empirical hydrodynamic VIV force model, in frequency domain and, a semi-empirical VIV force model based on the lift coefficient and Strouhal number, in time domain. Simulations results are analyzed through comparisons with experimental data and also limitations of the each model are discussed.

Determination of extension of life of corroded offshore pipelines using form and monte carlo structural reliability

Scipedia content — Wed, 03 Feb 2021 21:11:31 +0100

The evaluation of the structural strength of an offshore pipeline after 25 years of service is an important issue for extending its lifespan. This is an important environmental and economic issue, especially when the pipeline is related to the oil and gas industry. Remaining strength after corrosion effects are included in the performance equation and can be determined by using maximum operating pressure and capacity equations. The results are then compared from burst test results. In this study, Bayesian updating of probability of failure is used to evaluate the updated probability of failure. The performance equations from the two main codes on corrosion used in this study are B31G and DNV-RP-F101 and they are used validate the results. The sensitivity analysis of the variables such as defect depth and thickness is considered in the analysis. This method could be adopted for evaluating the service life extension and evaluation of pipelines working under extreme environments. FORM and Monte Carlo simulations will be used to determine the updated probability of failure. The method could be used for many engineering structures where either practical approaches are not feasible to determine the remaining life of the structure or the uncertainty of the expected results is too high. The evidence concluded in this study could be used by industry to enhance our understanding of the mechanisms for pipeline failure and processes necessary for its preservation.

Repair of In-Service HDPE Water Distribution Pipe

Scipedia content — Wed, 03 Feb 2021 21:11:06 +0100

n extensive, detailed survey of users of high density polyethylene (HDPE) water pipe in the United States and Europe, as well of manufacturers of appropriate products, has been conducted to determine the practicality and effectiveness of inservice field repairs of the HDPE pipe, including both fusion and non-fusion techniques. As a result of the study, commercially available mechanical (non-fusion) repair fittings and methods that have been successfully employed have been identified, based on their relative convenience and reliability. The present study focused on water distribution pipelines and force mains of sizes 2-in. through 16-in.

Multi-scale overlapping domain decomposition to consider local effects in the analysis of pipes

Scipedia content — Wed, 03 Feb 2021 21:06:12 +0100

Elevated pipelines are commonly encountered in petro-chemical and industrial applications. Within these applications, pipelines normally span hundreds of meters and are thus analysed using beam-type onedimensional finite elements when the global behaviour of the pipeline is sought at a reasonably low computational cost. Standard beam-type elements, while computationally economic, are based on the assumption of rigid cross-section. Thus, they are unable to capture the effects of cross-sectional localized deformations. Such effects can be captured through shell-type finite element models. For long pipelines, shell models become prohibitively expensive. Within this context, the present study formulates an efficient numerical modelling technique which effectively combines the efficiency of beam-type solutions while retaining the accuracy of shell-type solutions. An appealing feature of the model is that it is able to split the global analysis based on simple beam-type elements from the local analysis based on shell-type elements. This is achieved through a domain-decomposition procedure within the framework of the bridging multi-scale method of analysis. Solutions based on the present model are compared to those based on full shell-type analysis. The comparison demonstrates the accuracy and efficiency of the proposed method.

Intentional Destructive Testing: A Means for Establishing Mechanical Integrity

Scipedia content — Wed, 03 Feb 2021 21:04:15 +0100

Pipeline operators have at their disposal multiple resources for evaluating the integrity of identified features and anomalies. With advances in in-line inspection technology, the pipeline industry is being called upon to evaluate an ever-increasing number of features. When a feature is identified as a threat and severe enough to warrant further investigation, operators are faced with sometimes significant costs, including those associated with excavation activities."/jats:p" "jats:p"In this paper the authors provide guidance on the benefits associated with full-scale testing for evaluating mechanical integrity, referred to Intentional Destructive Testing (IDT). Unlike many assessment techniques that require the development and implementation of assumed operating and boundary conditions, well-designed IDT programs are able to replicate in situ conditions to provide operators with a clear understanding regarding the behavior of pipeline features and anomalies by simulating operating conditions and loading."/jats:p" "jats:p"Three case studies are included in this paper to demonstrate the merits of the IDT approach including the assessment of dents subjected to cyclic pressures, burst testing vintage pipes having long seam weld crack-like features, and evaluating the reinforcement of girth welds using composite materials. In using IDT operators have improved confidence in predicting the behavior of identified features to ensure that maintenance resources are properly allocated for excavating and repairing anomalies.

Investigating the implementation of potential strategies for enhancing urban mobility and a city logistics system on the island of Corfu

Scipedia content — Wed, 03 Feb 2021 21:00:36 +0100

The aim of this paper is to identify potential strategies for establishing more sustainable transport systems, in the island of Corfu, Greece. Thus, it investigates the implementation of “intermediate” and “flexible” transport and logistics schemes, operated by eco-friendly vehicles, allowing Corfu Island to achieve high standards of energy efficiency and environmental quality. With an ultimate scope to achieve remarkable modal shift from private transport to eco and energy efficient sustainable services and significant rationalization of freight delivery services, the suggested strategies aim to achieve: reduction of private traffic, improvement of passengers’ local mobility, rationalization and optimization of freight distribution on the island. Interviews with people working in the transport related field are utilized as the main research instrument and shed light on the needs and requirements of a reorganized transport system for both passengers and goods in the island. The investigation conducted, shows that the island needs a reduction of car use, improvement of public transport services and logistic services optimization. Therefore, three potential measures are proposed and further analyzed.

Towards a more Secure ATC Voice Communications System

Scipedia content — Wed, 03 Feb 2021 20:58:16 +0100

Contradictory to communication safety in the aviation field communication security has received relatively little attention to date, although the threats regarding air traffic security have been rapidly increasing in recent years. Within the project GAMMA (Global ATM Security Management) the German Aerospace Center (DLR) is developing a prototype to support air traffic controllers (ATCO) in detecting intrusions into the air ground voice system and therefore allow subsequent mitigating actions to be conducted.

Evolutionary agent-based simulation of the introduction of new technologies in air traffic management

Scipedia content — Wed, 03 Feb 2021 20:46:27 +0100

urate simulation of the effects of integrating new technologies into a complex system is critical to the modernization of our antiquated air traffic system, where there exist many layers of interacting procedures, controls, and automation all designed to cooperate with human operators. Additions of even simple new technologies may result in unexpected emergent behavior due to complex human/machine interactions. One approach is to create high-fidelity human models coming from the field of human factors that can simulate a rich set of behaviors. However, such models are difficult to produce, especially to show unexpected emergent behavior coming from many human operators interacting simultaneously within a complex system. Instead of engineering complex human models, we directly model the emergent behavior by evolving goal directed agents, representing human users. Using evolution we can predict how the agent representing the human user reacts given his/her goals. In this paradigm, each autonomous agent in a system pursues individual goals, and the behavior of the system emerges from the interactions, foreseen or unforeseen, between the agents/actors. We show that this method reflects the integration of new technologies in a historical case, and apply the same methodology for a possible future technology.

Shift Work and Labor Productivity in Urban Sewer Construction

Scipedia content — Wed, 03 Feb 2021 20:40:29 +0100

Sewer construction in urban areas often has significant impacts on work zone traffic control, traffic flow, and safety. Contractors typically introduce night shifts to meet contract schedule and to reduce traffic congestion. However, there is a lack of understanding of how shift work is associated with labor productivity in sewer construction. This research investigated labor productivity of ten major activities in sewer and drainage construction in Ho Chi Minh City, Vietnam when these activities were performed in both day and night shifts. Levene’s tests and t-tests were employed to analyze the data and investigate the research hypothesis. Results revealed that four activities were significantly sensitive to shift work and the other six activities were not. Pavement cutting and timber piling activities had higher productivity in day shifts. In contrast, steel sheet piling and manhole concreting were more productive in night shifts. Labor productivity of excavation, formwork installation, rebar fabrication/installation, pipe installation, sand filling, and asphalt pavement was not significantly different between the two shifts. The results were verified by the experienced site managers/engineers through structured interviews. The findings form this paper help contractors effectively manage their sewer projects by allocating resources appropriately to construction activities between the day and night shifts.

The Future of Assisted Living and Intelligent Mobility

Scipedia content — Wed, 03 Feb 2021 20:35:45 +0100

Dynamic stochastic scheduler for integrated arrivals and departures

Scipedia content — Wed, 03 Feb 2021 20:33:05 +0100

In terminal airspace, inefficient operations occur frequently due to constrained airspace and uncertainty. Choke points can easily form in the terminal area and therefore reduce the efficiency of the entire National Airspace System. Based on previous work on scheduling of aircraft arrivals and departures with shared fixes in terminal airspace and uncertainty in departure and arrival times, this work extends the previous stochastic scheduler with dynamic capability such that the scheduler can be sequentially applied to air traffic in terminal airspace with a much larger time frame through sliding windows instead of a static 30-minute traffic scenario. Results show that great delay savings can be achieved by using the dynamic stochastic scheduler relative to current air traffic control procedures. With a 30-minute time window, if an aggressive solution is chosen, on average 5.2 hours can be saved in a day in Los Angeles out of the 30% arrivals and 10% departures that are covered in the experiment. The expected value of annual fuel saving would be more than 10 million dollars. However, the cost of potential controller intervention, which results from the uncertainty of estimated departure and arrival times, will increase by 50% on average. If a moderate solution is chosen instead, with the same expected controller intervention as using current procedure, more than four hours delay saving can still be expected. When uncertainty of departure time increases with look-ahead time, experiments show that optimizations with large windows still find better solutions than the ones with small windows when delay saving is moderate. However, when delay saving is high, time-varied uncertainty plays a more important role than window size, where a small window is preferred for finding good solutions.

Estimating Travel Time Distribution under Different Traffic Conditions

Scipedia content — Wed, 03 Feb 2021 20:31:45 +0100

Increasing mobility and congestion results in an increase in travel time variability and in a decrease in reliability. Reliability becomes an important performance measure for transportation facilities. A variety of performance measures have been proposed to quantify it. Many of these indicators are based on percentiles of travel time. The knowledge of the distribution of travel time is needed to properly estimate these values. Congestion distorts the distribution and particular statistical distributions are needed. Different distributions have been proposed in the literature. In a previous paper, we presented a comparison of six statistical distributions used to model travel time. These six distributions are the Lognormal, Gamma, Burr (extended by Singh-Maddala), Weibull, a mixture of two Normal distributions and a mixture of two Gamma distributions. In this paper a probabilistic modeling of travel time which takes into account the levels-of-service is given. Levels of service are identified, then travel time distributions are modeled by level of service. This results in a very good fit between the empirical and modeled distributions Moreover, the adjustment was improved, thanks to the calibration of “Bureau of Public Roads” functions, linking the travel time to the traffic flow by level of service. The superiority of the Singh-Maddala distribution appears in many cases. This has been validated, thanks to travel time data from the same site at another period. However the parameters of the distributions vary from one year to another, due to changes in infrastructure. The transferability of the approach, not performed, will be based on travel time data on another site.

Document type: Conference object

Race 2050: trends in the demand for transportation systems

Scipedia content — Wed, 03 Feb 2021 20:27:52 +0100

This paper aims to present the results of an assessment of the crucial driving forces and demand challenges that the European transport industry faces, raising awareness for the demand-side driving forces influencing transport systems development and foreseeing its evolution, highlighting the major factors structuring world demand for transport equipment, infrastructure and supporting systems up to 2030 and beyond, such as gross domestic product (GDP) evolution, Ageing, Urbanization Growth, Environmental Challenges, Energy, Congestion, etc., are discussed with a particular focus on future urban mobility requirements. This paper highlights the main conclusions on future demand for transport systems, developed in the course of European Union (EU) funded Research Project RACE 2050 ‘Responsible Innovation Agenda for Competitive European Transport Industries up to 2050’.

A neurophysiological training evaluation metric for Air Traffic Management

Scipedia content — Wed, 03 Feb 2021 20:27:00 +0100

The aim of this work was to analyze the possibility to apply a neuroelectrical cognitive metrics for the evaluation of the training level of subjects during the learning of a task employed by Air Traffic Controllers (ATCos). In particular, the Electroencephalogram (EEG), the Electrocardiogram (ECG) and the Electrooculogram (EOG) signals were gathered from a group of students during the execution of an Air Traffic Management (ATM) task, proposed at three different levels of difficulty. The neuroelectrical results were compared with the subjective perception of the task difficulty obtained by the NASA-TLX questionnaires. From these analyses, we suggest that the integration of information derived from the power spectral density (PSD) of the EEG signals, the heart rate (HR) and the eye-blink rate (EBR) return important quantitative information about the training level of the subjects. In particular, by focusing the analysis on the direct and inverse correlation of the frontal PSD theta (4-7 (Hz)) and HR, and of the parietal PSD alpha (10-12 (Hz)) and EBR, respectively, with the degree of mental and emotive engagement, it is possible to obtain useful information about the training improvement across the training sessions.

Efficient rate-adaptive certificate distribution in VANETs

Scipedia content — Wed, 03 Feb 2021 20:25:15 +0100

Car-to-X communication systems, often called vehicular ad-hoc networks (VANETs), are in the process of entering the mass market in upcoming years. Thereby, security is a core point of concern due to the intended use for safety critical driver assistance systems. However, currently suggested security mechanisms introduce significant overhead into Car-to-X systems in terms of channel load and delay. Especially, the usage of on the fly distributed pseudonym certificates leads to a trade off between channel load and authentication delay, which may lead to significant packet loss. Thus, this work studies a novel concept for pseudonym certificate distribution in VANETs using rate-adaptive certificate distribution based on monitoring a vehicle's environment. Thereby, the cyclic certificate emission frequency is adapted on the fly based on cooperative awareness metrics for discrete parts of the vehicle's surrounding. The obtained mechanism is evaluated in a highway as well as an urban simulation scenario to show its suitability for a broad range of traffic conditions. Thereby, we find that it is able to significantly outperform the currently standardized approach for pseudonym certificate distribution in VANETs based on ETSI ITS standards. Thus, it should be regarded for further development of future VANETs.

NextGen technologies on the FAA's standard terminal automation replacement system

Scipedia content — Wed, 03 Feb 2021 20:23:04 +0100

This paper describes the integration, evaluation, and results from a high-fidelity human-in-the-loop (HITL) simulation of key NASA Air Traffic Management Technology Demonstration - 1 (ATD- 1) technologies implemented in an enhanced version of the FAA's Standard Terminal Automation Replacement System (STARS) platform. These ATD-1 technologies include: (1) a NASA enhanced version of the FAA's Time-Based Flow Management, (2) a NASA ground-based automation technology known as controller-managed spacing (CMS), and (3) a NASA advanced avionics airborne technology known as flight-deck interval management (FIM). These ATD-1 technologies have been extensively tested in large-scale HITL simulations using general-purpose workstations to study air transportation technologies. These general purpose workstations perform multiple functions and are collectively referred to as the Multi-Aircraft Control System (MACS). Researchers at NASA Ames Research Center and Raytheon collaborated to augment the STARS platform by including CMS and FIM advisory tools to validate the feasibility of integrating these automation enhancements into the current FAA automation infrastructure. NASA Ames acquired three STARS terminal controller workstations, and then integrated the ATD-1 technologies. HITL simulations were conducted to evaluate the ATD-1 technologies when using the STARS platform. These results were compared with the results obtained when the ATD-1 technologies were tested in the MACS environment. Results collected from the numerical data show acceptably minor differences, and, together with the subjective controller questionnaires showing a trend towards preferring STARS, validate the ATD-1/STARS integration.

Sustainable transport solutions at a crossroads in developing countries: insights and perspectives

Scipedia content — Wed, 03 Feb 2021 20:20:42 +0100

This paper reviews the solutions to the matters of sustainable transport at a crossroads in developing countries. In the process, the paper recommends rethinking sustainable transport solutions in developing countries, given that current and previous efforts have failed to permanently reverse problems of automobile dependency, an inefficient public transport system and network traffic congestion for example. In addition, land use and transport planning actions and interventions have been found to promote fragmentation and gentrification of spaces, places and people. This paper analytically reviews desktop studies covering the sustainable transport from developing countries to establish the existing situation as well as crafting a policy and intervention lever departure points. Making use of over 20 years of research, consultancy and practical experience, the authors aim to define possible future sustainable transport intervention levers and focus on areas within developing countries.

Innovative Joint Designed for an 84 in. Raw Water Transmission Main Tunnel Carrier Pipe

Scipedia content — Wed, 03 Feb 2021 20:14:29 +0100

Lake Travis is located northwest of the City of Austin, Texas. Due to the unanticipated population growth in the area, Austin Water Plant No. 4 was designed and constructed in the hill country to extract water from the lake. The raw water line is located between the raw water pump station and the water treatment plant-raw water flume. This part of the project consisted of approximately 3,900 linear ft of 84-in. steel water pipe installed in a tunnel. The installation contractor had concerns that its crews would have fit-up problems with butt-welded field joints due to numerous horizontal curves so the contractor requested alternative solutions. Consequently, the pipe manufacturer and installation contractor worked in cooperation to devise an appropriate jointing system that fit the intended application. The joint was unique in that it allowed for lap welding to be utilized for deep insertion, which in turn permitted greater flexibility for installation of the steel liner pipe into the tunnel. The objectives of this paper will be three-fold: (1) to describe the art and engineering of jointing steel pipe (the process of welding steel pipe joints, the differences between butt welding and lap welding, beveled joints, etc), (2) to discuss the design and subsequent redesign of the field joints on this project, and (3) to discuss the installation process. The paper will discuss these items from both a manufacturer's and an installer's perspective and will describe the background of what led up to the final design and manufacture of the field joint supplied. Changes that took place between the design and approval process and the final installation will also be explained in detail. The contents of the paper will be useful to owners of large-diameter water transmission systems, design engineers, and the construction community.

The Uncertainty of Future Commercial Shale Gas Availability

Scipedia content — Wed, 03 Feb 2021 20:13:34 +0100

Numerous top-down resource estimates have indicated that shale deposits hold enormous volumes of methane globally. Until recently detailed delineations of shale gas resources and their production have occurred exclusively in North America. The driving forces and enabling conditions behind the rapid exploitation of shale gas resources in North America are assessed to determine if these are transferable to the rest of world. No two shale deposits are created equal and the mere existence of shale does not guarantee success of future gas production. A formation may hold too little oil or gas — or it may not be brittle enough for fracking to work effectively. The challenge is to find so-called ‘sweet spots’, i.e., plays with high flow rates, once stimulated. The amount of shale gas that can be commercially produced under current and future market conditions is determined by the quantity and thermal maturity of shale’s organic content, by regional technology cost, access to transmission pipelines and regional gas price levels. The shale gas rush in North America has caused a precipitous drop in natural gas wellhead prices - from some $11/GJ in 2008 to less than $3/GJ in 2012. A review of the economics of shale gas production indicates that (a) the resource appraisal process for conventional gas resources is unsuitable for unconventional gas resources; (b) field development requires continuous (on-the-go) investment in fracking to stimulate well pressure, and (c) depressed US gas prices currently fail to cover full finding and development costs. Unless well technology improves and completion cost declines rapidly, the maturation process of technically recoverable shale gas resources to proved reserves will be delayed. Time value of money effects undermine the commercial availability of shale gas, particularly in regions where ineffective permitting procedures and slow societal acceptance tend to put additional negative pressure on shale field development speed.

A Framework and a Tool for Semantic Annotation of POIs in OpenStreetMap

Scipedia content — Wed, 03 Feb 2021 20:09:34 +0100

Current mobile systems for assisted navigation have limited effectiveness in satisfying user needs. The information content supporting location-based service discovery and path calculation is usually shallow. Semantic-based technologies can allow to overcome these limitations, by exploiting accurate and meaningful descriptions of locations, Points of Interest (POIs), road segments and environmental conditions. We present here a general framework leveraging an enriched cartography, which may be useful not only to enhance travel satisfaction and safety, but also to regulate vehicle efficiency, traffic and environmental impact.The availability of annotated map data is a crucial requirement to make practically viable such a proposal. Unfortunately, the majority of available systems is developed upon closed and proprietary solutions for both maps and software applications, so third parties cannot extend their functionality. To go beyond this restriction, the framework presented here is based on open standards and tools: in particular, it leverages Semantic Web technologies and crowd-sourced maps available from OpenStreetMap (http://www.openstreetmap.org/), enriching nodes and POIs with semantic annotations to enable innovative Location Based Services (LBSs) for traveling users. Particularly, the paper proposes a general method for storing semantic annotations into OpenStreetMap road nodes and POIs. A user-friendly software tool is also presented for editing annotations through a fully visual user interface, based on simple drag-and-drop operations, implemented as a plugin for the popular open source JOSM OpenStreetMap editor (http://josm.openstreetmap.de/), that will make any OpenStreetMap contributor capable of enriching maps with semantic information. Finally, a semantic-enhanced navigation tool is proposed, capable of exploiting the enriched cartography. Early users’ evaluation assesses the effectiveness of such a proposal.

Determination the relation between the target regulations about End of Life Vehicles (ELVs) and greenhouse gas emissions in Turkey

Scipedia content — Wed, 03 Feb 2021 20:04:58 +0100

ınay, Galip (Balikesir Author)

The aim of this study was to determine the potential reduction on GHG emission from transportation sector, in particular from passenger cars (according to car figures in 2016). The GHG reductions were determined for different scenarios (1) current situation (2) to implement of the taxation system based on carbon emission (3) to make reduction on taxes (rate of 18% and 27%) and (4) to apply a regulation for End of Life Vehicles (ELVs) We found that the best scenario is to apply the regulation for ELVs. If the regulation is applied for banning vehicles which were produced before 2000, 1996 and 1990, the reduction rate of CO2 emission would be 48%, 36% and 26%, accordingly. The CO2 reduction rates in transportation sector calculated for different scenarios will change approximately 2% to 15%. Consequently, the total GHG emission reduction in Turkey will be about 0.2% to 2%.

Reactive logic in software-defined networking: Measuring flow-table requirements

Scipedia content — Wed, 03 Feb 2021 20:01:02 +0100

The capability of a network is ultimately bounded by limitations of the devices that compose it. In this paper we argue that Software-Defined Networking (SDN) can increase the importance of certain limitations, such as the size and the flexibility of switches forwarding tables. In particular we focus on the implications of reactive installation of flow entries in the switch fabric: by analyzing traffic traces captured in different scenarios we show the existence of a trade-off between the size of the flow table and the rate of dynamic installation of a missing or expired rule. We leverage on this finding to further show that reactive flow (re-)configuration is a promising mechanism for improving the traffic engineering flexibility with no additional requirement in terms of flow table size. We examine links located in various parts of the network and we consider different flow definitions to evaluate the feasibility of using SDN controllers in both access and core network scenarios. Keywords-Network communications, Software-Defined- Networking, network measurements.

Multi-depth cross-calibration of remote eye gaze trackers and stereoscopic scene systems

Scipedia content — Wed, 03 Feb 2021 19:59:03 +0100

We present a robust and accurate technique for the cross-calibration of 3D remote gaze trackers with stereoscopic scene vision systems between which no common imaging area exists. We empirically demonstrate that a multi- depth calibration approach yields remarkably superior results for obtaining 3D Point-of-Gaze (PoG) when compared with traditional methods using monocular scene cameras and co- planar eye gaze calibration points. I. INTRODUCTION Remote gaze trackers have been in use for various ap- plications together with scene cameras to determine the point of gaze (PoG) of human subjects on an imaged scene. Several types of applications benefit from the use of such systems including vehicle driver training and advanced driver assistance systems, the context in which the results herein have been obtained. The task of projecting back the 3D gaze direction onto the imaged scene requires a cross-calibration between the remote gaze tracking device and the scene. In most if not all of commercially available systems, this type of calibration is performed by requiring that test subjects fixate specific, pre- selected image points on a planar surface placed at a known distance such as on a computer screen or, by using a scene image from a monocular camera and treating it essentially as a 2D object (co-planar fixation calibration points). Such approaches are dependable when the subject's eye center is not highly offset from the scene camera(s). In other words, because the origin of the reference system of the scene cameras and the subject's eye center approximately coincide, the projection ray of any fixated object will also approximately lie on the line of sight regardless of the depth of the object. In such cases, the calibration process may be performed correctly. Otherwise, objects with different depths along the line of sight correspond to different image locations, and must be calibrated for as such. Our primary goal is to determine whether driver intent and driving-related actions can be predicted from qualitative and quantitative analyses of driver behavior. Toward this end, it is necessary to establish the correspondence between cephalo- ocular behavior and visual stimuli in such a way as to identify the elements in the visual field to which driver attention turns to. This type of information in turn may facilitate the task

From few to many: Using copulas and Monte Carlo simulation to estimate safety consequences

Scipedia content — Wed, 03 Feb 2021 19:54:05 +0100

With the introduction of more advanced vehicle technology, it is paramount to assess its safety benefit. Advanced driver assistance systems (ADAS) can reduce crashes and mitigate crash severity, if designed appropriately. Driver behavior models are integral to the ADAS design process, complementing time and resource intensive human participant experiments. The authors introduce a method to model driver responses to forward collision events by quantifying multivariate behavior with copulas and Monte Carlo simulation. This approach capitalizes on the data from small samples of crash events observed in naturalistic or simulator studies. Copulas summarize data by capturing the underlying joint distribution of variables, and Monte Carlo methods can be used to repeatedly sample from these distributions. A driver model can be parameterized with these samples, and run on a desktop driving simulation environment.

An Approach to Forecast Air Traffic Movements at Capacity-Constrained Airports

Scipedia content — Wed, 03 Feb 2021 19:48:13 +0100

Due to steadily growing air traffic, airports need a means to evaluate the capability of their infrastructure to handle future air traffic movements. Sound forecasts are needed for fundraising, within lawsuits, and in order to avoid misplanning. The quality of current forecasts is often queried. Hence, this work introduces parts of a tool chain that derives future air traffic movements out of transport scenarios and compares them to the capacity of an airport. Five consecutive models within the chain yield future air traffic movements for one airport considering passenger demand, a forecast of aircraft movements, airline preferences and airport capacity.

Developing a transdisciplinary approach to improve urban traffic congestion based on Product Ecosystem Theory

Scipedia content — Wed, 03 Feb 2021 19:39:09 +0100

Product Ecosystem Theory is an emerging theory that shows that disruptive “game changing” innovation is only possible when the entire ecosystem is considered. When environmental variables change faster than products or services can adapt, disruptive innovation is required to keep pace. This has many parallels with natural ecosystems where species that cannot keep up with changes to the environment will struggle or become extinct. In this case the environment is the city, the environmental pressures are pollution and congestion, the product is the car and the product ecosystem is comprised of roads, bridges, traffic lights, legislation, refuelling facilities, etc. Each one of these components is the responsibility of a different organisation and so any change that affects the whole ecosystem requires a transdisciplinary approach. As a simple example, cars that communicate wirelessly with traffic lights are only of value if wireless-enabled traffic lights exist and vice versa. Cars that drive themselves are technically possible but legislation in most places doesn’t allow their use. According to innovation theory, incremental innovation tends to chase ever diminishing returns and becomes increasingly unable to tackle the “big issues”. Eventually “game changing” disruptive innovation comes along and solves the “big issues” and/or provides new opportunities. Seen through this lens, the environmental pressures of urban traffic congestion and pollution are the “big issues”. It can be argued that the design of cars and the other components of the product ecosystem follow an incremental innovation approach. That is why the “big issues” remain unresolved. This paper explores the problems of pollution and congestion in urban environments from a product ecosystem perspective. From this a strategy will be proposed for a transdisciplinary approach to develop and implement solutions.

Developing an Engineering Based Integrity Management Program for Piping, Pipelines, and Plant Equipment

Scipedia content — Wed, 03 Feb 2021 19:32:42 +0100

Establishing integrity for piping and pipelines requires an understanding of the specific threats, their relationship to the overall condition of the system, and the mitigating measures required to assure safe operation. In the past, industry has relied on years of research and experience to develop a set of tools to analyze these threats and apply conservative solutions to ensure integrity and fitness for service. An effective integrity management program as discussed in this paper, known as the Engineering Based Integrity Management Program (EB-IMP), provides operators with a resource for integrating inspection results, analysis, and testing to qualify the components within a pressurized system."/jats:p" "jats:p"This paper presents a detailed discussion on how experience, advances in analytical techniques, experimental methods, and engineering rigor are combined to develop a tool to characterize and ensure system integrity. Several case studies are included to demonstrate how the EB-IMP method was used to evaluate the integrity of a piping system, as well as rail gondola cars used to transport coal. The intent with the approach presented in this paper is to foster further developments for advanced integrity management efforts.

Traffic routing in urban environments: The impact of partial information

Scipedia content — Wed, 03 Feb 2021 19:27:36 +0100

There are many studies concerning the problem of traffic congestion in cities. One of the best accepted solutions to relieving congestion involves optimization of resources already available, by means of balancing traffic flows to minimize travel delays. To achieve this optimization, it is necessary to collect and process Floating Car Data (FCD) from vehicles. In this paper the authors evaluate the repercussions of partial information on the overall traffic view, and consequently on the outcome of the optimization. The authors study focuses on the role of the user participation rate and the availability of Road Side Units to collect the FCD. By means of simulation the authors quantify the impact of partially-available information on the computation of route optimization, and how it impedes traffic flows. The authors results show that even minor uncertainties can significantly impact routing strategies and lead to deterioration in the overall traffic situation.

Spatio-temporal clustering for non-recurrent traffic congestion detection on urban road networks

Scipedia content — Wed, 03 Feb 2021 19:21:50 +0100

Non-Recurrent Congestion events (NRCs) frustrate commuters, companies and traffic operators because they cause unexpected delays. Most existing studies consider NRCs to be an outcome of incidents on motorways. The differences between motorways and urban road networks, and the fact that incidents are not the only cause of NRCs, limit the usefulness of existing automatic incident detection methods for identifying NRCs on urban road networks. In this paper we propose an NRC detection methodology to support the accurate detection of NRCs on large urban road networks. To achieve this, substantially high Link Journey Time estimates (LJTs) on adjacent links that occur at the same time are clustered. Substantially high LJTs are defined as those LJTs that are greater than a threshold. The threshold is calculated by multiplying the expected LJTs with a congestion factor. To evaluate the effectiveness of the proposed NRC detection method, we propose two novel criteria. The first criterion, high-confidence episodes, assesses to what extent substantially high LJTs that last for a minimum duration are detected. The second criterion, the Localisation Index, assesses to what extent detected NRCs could be associated with incidents. The proposed NRC detection methodology is tested for London’s urban road network. The optimum value of the congestion factor is determined by sensitivity analysis by using a Weighted Product Model (WPM). It is found out those LJTs that are at least 40% higher than their expected values should belong to an NRC; as such NRCs are found to maintain the best balance between the proposed evaluation criteria.

Document type: Article

A review and framework of Control Authority Transitions in automated driving

Scipedia content — Wed, 03 Feb 2021 19:16:34 +0100

The paper reviews some of the essentials of human-machine interaction in automated driving, focusing on control authority transitions. We introduce a driving state model describing the human monitoring level and the allocation of lateral and longitudinal control tasks. An authority transition in automated driving is defined as the process of changing from one static state of driving to another static state. Based on (1) who initiates the transition and (2) who is in control after the transition, we categorize transitions into four types: driver-initiated driver control (DIDC), driver-initiated automation control (DIAC), automation-initiated driver control (AIDC), and automation-initiated automation control (AIAC). Finally, we discuss the effects of human-machine interfaces on driving performance during transitions.

Micro-architectural simulation of in-order and out-of-order ARM microprocessors with gem5

Scipedia content — Wed, 03 Feb 2021 19:14:15 +0100

Heterogeneous multicore systems have gained momentum, specially for embedded applications, thanks to the performance and energy consumption trade-offs provided by inorder and out-of-order cores. Micro-architectural simulation models the behavior of pipeline structures and caches with configurable parameters. This level of abstraction is well known for being flexible enough to quickly evaluate the performance of new hardware implementations, such as future heterogeneous multicore platforms. However, currently, there is no open-source micro-architectural simulator supporting both in-order and out-of-order ARM cores. This article describes the implementation and accuracy evaluation of a micro-architectural simulator of Cortex-A cores, supporting in-order and out-of-order pipelines and based on the open-source gem5 simulator. We explain how to simulate CortexA8 and Cortex-A9 cores in gem5, and compare the execution time of ten benchmarks with real hardware. Both models, with average absolute errors of only 7 %, are more accurate than similar microarchitectural simulators, which show average absolute errors greater than 15 %.

The prospects of the use of thin-film heat-insulation coatings for the protection of the pipelines of heating systems and power equipment

Scipedia content — Wed, 03 Feb 2021 19:06:04 +0100

Heat loss in the heat supply systems of the Russian Federation reaches 300 million Gcal a year during transport. Excess heat loss is mostly due to the poor condition of the thermal insulation assemblies of pipelines and power equipment. Modern requirements for heat insulation coatings stipulate that they possess low thermal conductivity values, high mechanical properties, resistance to alternating loads and a vibration. The dynamics of market growth for thin-film heat-insulation coatings is positive today. Thin-film heat-insulation coatings are created by using hollow microspheres and various binders. Opinions of experts about the efficiency of their use differ. Generally, this is due to little research on thin-film heatinsulation coatings. Tests were conducted to determine the effects of various kinds of microspheres and binders on the mechanical and thermal characteristics of thin-film heat-insulation coatings. This was done to understand the efficiency of the use of thin-film heat-insulation coatings for heating systems and power equipment. During the testing of thin-film thermal insulation coatings, the conditions were simulated to be the same as the real operating conditions of pipeline heating systems and power equipment. The test results show the efficiency of thin-film heat-insulation coatings on the base of hollow glass microspheres and polymer binders. The use of such kinds of thin-film heatinsulation coatings allows for the reduction of heat loss from the surfaces of the pipelines and power equipment, which improves the mechanical properties of the coatings in comparison to the use of traditional materials.

A Multi-agent Intelligent System for on Demand Transport Problem Solving

Scipedia content — Wed, 03 Feb 2021 19:02:03 +0100

In recent years, urban traffic congestion and air pollution have become huge problems in many cities in the world. A possible investment in order to reduce congestion is to increase the number of passengers in vehicles, and to de-crease the number of vehicles on streets. This problem is defined as âon demand transportâ (ODT) problem. The ODT problem environment is defined by three components: the infrastructure of the city, the vehicles and the drivers. Clients formulate requests for transportation from a pickup, to a drop off places. These requests are received and must be served on real time by the set of vehicles, which require real time environment updates. This paper is a first step to model the ODT problem as multi-agent distributed planning problem. Our model relaxes some definitions and reduces the complexity of the ODT problem to allow better optimization.

Analysis and prediction of weather impacted ground stop operations

Scipedia content — Wed, 03 Feb 2021 18:58:00 +0100

When the air traffic demand is expected to exceed the available airport's capacity for a short period of time, Ground Stop (GS) operations are implemented by Federal Aviation Administration (FAA) Traffic Flow Management (TFM). The GS requires departing aircraft meeting specific criteria to remain on the ground to achieve reduced demands at the constrained destination airport until the end of the GS. This paper provides a high-level overview of the statistical distributions as well as causal factors for the GSs at the major airports in the United States. The GS's character, the weather impact on GSs, GS variations with delays, and the interaction between GSs and Ground Delay Programs (GDPs) at Newark Liberty International Airport (EWR) are investigated. The machine learning methods are used to generate classification models that map the historical airport weather forecast, schedule traffic, and other airport conditions to implemented GS/GDP operations and the models are evaluated using the cross-validations. This modeling approach produced promising results as it yielded an 85% overall classification accuracy to distinguish the implemented GS days from the normal days without GS and GDP operations and a 71% accuracy to differentiate the GS and GDP implemented days from the GDP only days.

The ladies' 4-week cycle challenge: experiences and insights

Scipedia content — Wed, 03 Feb 2021 18:54:32 +0100

eer-reviewed Limerick was designated as Ireland’s National Smarter Travel demonstration area in 2012. Limerick Smarter Travel (LST), which aims to promote sustainable travel in the City and suburbs, is a partnership between the Limerick Councils and the University of Limerick (UL). Within UL, final year projects and other research is on-going in the smarter travel subject area. Although cycling participation in Ireland is on the rise both nationally and locally within the Limerick community, travel survey data conducted by the LST team has demonstrated a significant gender gap exists among cyclists with far less women cycling than men. This paper is based on a final year project thesis: The Ladies’ 4-Week Cycle Challenge: An active research study of females investigating the barriers and motivators regarding cycling participation in Ireland. The research involved a group of females taking up cycling over a period of 4 weeks as a means of commuting to work/college. Following pre- and post-challenge interviews with the female participants a number of measures to encourage cycling participation among women are outlined along with recommendations for further research.

Development of Pipeline Leak Detection Technologies

Scipedia content — Wed, 03 Feb 2021 18:47:10 +0100

New development continues in pipeline leak detection technologies in order to meet the increasing demand of the oil, gas, chemical and water industry. After a review of the available technologies, this paper discusses the advances made in two key technologies: statistical volume balance and negative pressure wave."/jats:p" "jats:p"Some application examples in brine, multi-product and crude oil pipelines are presented to demonstrate the improvement in leak detection sensitivity and location accuracy.

GTA-m

Scipedia content — Wed, 03 Feb 2021 18:46:46 +0100

orne networks have potential applications in both civilian and military domains -- such as passenger in-flight Internet connectivity, air traffic control and in intelligence, surveillance and reconnaissance (ISR) activities. However, airborne networks suffer from frequent disruptions due to high node mobility, ad hoc connectivity and line-of-sight blockages. These challenges can be alleviated through the use of disruption-tolerant networking (DTN) techniques. In this paper, we propose GTA-m, a multi-copy greedy trajectory-aware routing protocol for airborne networks. GTA-m employs DTN capabilities and exploits the use of flight information to forwarded bundles \\emph{greedily} to intended destination(s). To alleviate the local minima issues that are inherent in greedy algorithms, GTA-m allows $m \\geq 1$ copies of each bundle to be replicated throughout the entire network. We study the performance of GTA-m by simulating flights with varying numbers of aircraft and ground stations. Through simulations in OPNET, we show that GTA-m improves the average bundle delay by 34\\% and 52\\% as compared to conventional DTN routing protocols such as Spray-and-Wait and Epidemic respectively.