Scipedia: Documents published in 2017

Air connectivity in remote regions: A comprehensive review of existing transport policies worldwide

Scipedia content — Tue, 16 Feb 2021 13:40:09 +0100

consensus exists in the literature on the strong link between air connectivity and economic growth and development. The need for connecting people and markets is part of national policies in different territories. The existence of remote areas, that is, those that under strict market criteria would not be transport supplied due to lack of commercial profitability, has led to the development of different public policies aimed to support air connectivity in regions where commercial airline operations are not viable. This paper provides a mapping of existing policies applied worldwide to provide air connectivity to remote areas, and critically reviews policies promoting air connectivity, including: 1) route-based policies; 2) passenger-based policies; 3) airline-based policies; and 4) airport-based policies. This effort is the first to compile and critically analyze all the existing alternatives to provide air connectivity in remote areas and to report on experiences worldwide. Moreover, we develop a novel taxonomy of existing public policies when it comes to providing air connectivity to remote areas. After reviewing different policy options and instruments applied globally, the paper ends with a policy discussion.

Analysis of the impact of bilateral and transit quotas on Turkey's international trade by road transport : an integrated maximum flow and gravity model approach

Scipedia content — Tue, 16 Feb 2021 13:37:03 +0100

Çekyay, Bora (Dogus Author) -- Palut, Peral Toktaş (Dogus Author) -- Özaydın, Özay (Dogus Author) We explore whether bilateral and transit quotas applied by EU countries on Turkey have a negative impact on Turkey's international trade by road transport. Therefore, Turkey's exports by road transport to selected European countries are analyzed in a panel-data framework for the period 2005–2014. We estimate the aggregate effect of different quota types on trade between Turkey and European countries by using an approach that integrates the max-flow and gravity models. In the gravity model, for each country, a single value representing the aggregate restricting effect of different quota types is needed. The single values are obtained by solving multiple max-flow problems, where constraining effects of different quota types are modeled as arc capacities. The results of the gravity model suggest a loss in Turkish exports by road transport because of the quotas imposed by other countries. Most of the negative impact results from bilateral quotas rather than from transit quotas, whose effect is rather marginal.

Economics of electric vehicles for city logistics

Scipedia content — Tue, 16 Feb 2021 13:23:05 +0100

Within the FREVUE project 80 fully electric freight vehicles have been deployed. It showed that city logistics operations can be performed by electric freight vehicles, but that at the moment the high vehicle purchasing costs are still a barrier for large scale utilisation of electric freight vehicles for logistics operations. Only for small EFVs (lighter than 3.5 tons) a short term feasible business case is possible. For the larger vans and rigid trucks, a feasible business case is not yet possible from an operator’s perspective, often not even with subsidies. Copyright © 2018 Society of Automotive Engineers of Japan, Inc. All rights reserved

From the testing to the deployment of self-driving cars: Legal challenges to policymakers on the road ahead

Scipedia content — Tue, 16 Feb 2021 13:22:50 +0100

Self-driving cars and self-driving technology are tested on public roads in several countries on a large scale. With this development not only technical, but also legal questions arise. This article will give a brief overview of the legal developments in multiple jurisdictions – California (USA), United Kingdom, and the Netherlands – and will highlight several legal questions regarding the testing and deployment of self-driving cars. Policymakers are confronted with the question how the testing of self-driving cars can be regulated. The discussed jurisdictions all choose a different approach. Different legal instruments – binding regulation, non-binding regulation, granting exemptions – are used to regulate the testing of self-driving cars. Are these instruments suitable for the objectives the jurisdictions want to achieve? As technology matures, self-driving cars will at some point become available to the general public. Regarding this post-testing phase, two pressing problems arise: how to deal with the absence of a human driver and how does this affect liability and insurance? The Vienna Convention on Road Traffic 1968 and the Geneva Convention on Road Traffic 1949, as well as national traffic laws, are based on the notion that only a human can drive a car. To what extent a different interpretation of the term ‘driver’ in traffic laws and international Conventions can accommodate the deployment of self-driving cars without a human driver present will be discussed in this article. When the self-driving car becomes reality, current liability regimes can fall short. Liability for car accidents might shift from the driver or owner to the manufacturer of the car. This could have a negative effect on the development of self-driving cars. In this context, it will also be discussed to what extent insurance can affect this development.

Leakage detection and localization on water transportation pipelines: a multi-label classification approach

Scipedia content — Tue, 16 Feb 2021 13:13:14 +0100

Zavrak/0000-0001-6950-8927; Kara, Resul/0000-0001-8902-6837; Kayaalp, Fatih/0000-0002-8752-3335 WOS: 000426865100007 One of the main problems of water transportation pipelines is leak which can cause water resources loss, possible human injuries, and damages to the environment. There are many studies in the literature focusing on detection and localization of leaks in the water pipeline systems. In this study, we have designed a wireless sensor network-based real-time monitoring system to detect and locate the leaks on multiple positions on water pipelines by using pressure data. At first, the pressure data are collected from wireless pressure sensor nodes. After that, unlike from the previous works in the literature, both the detection and localization of leakages are carried out by using multi-label learning methods. We have used three multi-label classification methods which are RAkELd, BRkNN, and BR with SVM. After the evaluation and comparison of the methods with each other, we observe that the RAkELd method performs best on almost all measures with the accuracy ratio of 98%. As a result, multi-label classification methods can be used on the detection and localization of the leaks in the pipeline systems successfully.

Longitudinal Jerk Estimation of Driver Intentions for Advanced Driver Assistance Systems

Scipedia content — Tue, 16 Feb 2021 13:10:52 +0100

International audience; This work aims at estimating the longitudinal jerk of the vehicle as it is acted by a human driver, in the context of preventive safety. A reliable estimate is needed to infer the current driver intention in an advanced driving assistance system developed by the authors. The derived intention-oriented model for the longitudinal dynamics is embedded into an enhanced Kalman filter that provides the user with a knob to trade off between responsiveness of the estimate and noise rejection. The scheme is fit for on-line usage, relies on signals commonly available on the CAN bus of modern vehicles, and requires a very limited number of parameters. Its effectiveness is validated on experimental data, and compared with alternative approaches.

The Safety of Transnational Imported Second-Hand Cars: A Case Study on Vehicle-to-Vehicle Crashes in Romania

Scipedia content — Tue, 16 Feb 2021 13:07:58 +0100

Certain features of imported second-hand cars (e.g., age, degree of wear and tear, technical design) can increase their likelihood for traffic crashes. Three official datasets which cover an eight year period (2008–2015) are used to test the connection between importation of second-hand cars and different types of traffic crashes. The traffic crashes database was provided by the Traffic Department of the General Inspectorate of Romanian Police (GIRPTD). The car registration database was provided by Driving-License and Vehicles-Registration Direction (DLVRD). Right-hand driving (RHD) cars database was provided by the Romanian Automotive Registry (RAR). A spatio-temporal visualization of data was performed using Geographic Information System (GIS) while for the statistical analysis we use regression models and Pearson-Correlation-coefficient. The analysis suggests that a significant part of the variation in the volume of traffic accidents can be explained by the volume of imported second-hand cars at the county level. Moreover, an even stronger direct relation exists between the number of imported second-hand cars and Severe Traffic Accidents but also in the case of RHD imported second-hand cars. The overall impact of imported second-hand cars on the traffic safety in Romania is significant but small in comparison to other types of car registration. Study results belong to the category of empirical evidence production which can improve the quality of existing traffic regulations focused both on organizing and ensuring traffic safety, and on the policy of sustainable transport infrastructure development.

Document type: Article

Environmental sustainability in the service industry of transportation and logistics service providers: Systematic literature review and research directions

Scipedia content — Tue, 16 Feb 2021 13:03:07 +0100

This paper provides a systematic review on the subject of environmental sustainability in the service industry of logistics service providers (LSPs) to analyse the advances of the literature on the topic and pick out appropriate research questions to investigate. The literature review has been performed using two academic databases and spans the years 1960–2014. The paper shows that despite the increasing number of papers on the subject, several areas of research are still being neglected. In particular, the paper highlights six main literature gaps concerning the classification of green initiatives, the impact of green initiatives on LSP performance, the evaluation of sustainability performance, the factors influencing the adoption of environmental sustainability initiatives, the customer perspective in the sustainable supply chain, and the information and communication technologies supporting green initiatives. Starting from these six gaps, eight research questions have been identified. These research questions represent possible emerging areas of investigation on the topic.

Intermodal connectivity in Europe, an empirical exploration

Scipedia content — Tue, 16 Feb 2021 12:59:42 +0100

In this paper we analyse the intermodal connectivity in Europe. The empirical analysis is to our knowledge the first empirical analysis of intermodal connections, and is based on a comprehensive database of intermodal connections in Europe. The paper focuses on rail and barge services, as they are the backbone of intermodal freight transport chains. The empirical analysis reveals that rail and barge are complementary, in the sense that the number of overlapping origin-destination pairs is limited and barge connections are across relatively short distances, while rail generally is used for larger transport distances. In addition the lowest transport distances of rail and barge services are relatively low. Services over short distances are feasible, especially between ports and for mountain crossings. For port-to- hinterland services, various services cover distances below 100 km. This paper provides a first indication (albeit no conclusive evidence) that a higher competition intensity between rail operators in a port may lower the distance of the shortest rail service. The analysis also reveals service frequencies are on average very substantial: around four services per week. These frequencies diminish with the distance of the service. These insights are valuable for companies involved in developing new services and provide a basis for further research.

The economic implications of natural gas infrastructure investment

Scipedia content — Tue, 16 Feb 2021 12:57:40 +0100

Since 2001, the Indonesian government has issued natural gas master plans annually holding the planned gas infrastructure developments in order to motivate private parties who are not motivated due to the lack of the gas infrastructure increase. Since 2002, there were only three segments of gas pipelines that have been tendered (IEA, 2008) which are Gresik-Semarang and Bontang-Semarang (Kalimantan to Java Pipeline) in 2005, and Cirebon-Semarang in 2006 that have no supply anymore. The current transmission and distribution lines of 3,762.32 km and 4,554.54 km, respectively, are very small compared to developed countries in a similar gas resource position as Indonesia. The paper views the role of natural gas infrastructure for economic growth and energy security in Indonesia. The economic impacts of natural gas infrastructure are analyzed through the Computable General Equilibrium model. The results show that all financing scenarios have positive impacts on the various macro-economic indicators as well as on sectorial output and employment.

A headway to improve PTW rider safety within the EU through three types of ITS

Scipedia content — Tue, 16 Feb 2021 12:38:57 +0100

Black-Box Calibration for ADCs With Hard Nonlinear Errors Using a Novel INL-Based Additive Code: A Pipeline ADC Case Study

Scipedia content — Tue, 16 Feb 2021 12:36:43 +0100

This paper presents a digital nonlinearity calibration technique for ADCs with strong input-output discontinuities between adjacent codes, such as pipeline, algorithmic, and SAR ADCs with redundancy. In this kind of converter, the ADC transfer function often involves multivalued regions, where conventional integral-nonlinearity (INL)-based calibration methods tend to miscalibrate, negatively affecting the ADC's performance. As a solution to this problem, this paper proposes a novel INL-based calibration which incorporates information from the ADC's internal signals to provide a robust estimation of static nonlinear errors for multivalued ADCs. The method is fully generalizable and can be applied to any existing design as long as there is access to internal digital signals. In pipeline or subranging ADCs, this implies access to partial subcodes before digital correction; for algorithmic or SAR ADCs, conversion bit/bits per cycle are used. As a proof-of-concept demonstrator, the experimental results for a 1.2 V 23 mW 130 nm-CMOS pipeline ADC with a SINAD of 58.4 dBc (in nominal conditions without calibration) is considered. In a stressed situation with 0.95 V of supply, the ADC has SINAD values of 47.8 dBc and 56.1 dBc, respectively, before and after calibration (total power consumption, including the calibration logic, being 15.4 mW).

Peer reviewed

Three layers of energy law for examining CO2 transport for carbon-capture and storage

Scipedia content — Tue, 16 Feb 2021 12:32:05 +0100

This research is a legal analysis concerning four scenarios for cross-border carbon dioxide (CO2) transport that could increase the deployment of carbon-capture and storage (CCS) deployment in Europe. The legal analysis categorizes the law into three levels-international, national and local-and considers the four scenarios in light of these three levels of energy law. Upon reviewing the four scenarios, it is clear that the Rotterdam Nucleus (referred to as the 'Pilot Case') is the leading scenario and as a result it is explored in more detail. The potential Pilot Case is based on the development of Rotterdam (in the Netherlands) as a southern North Sea hub. Under this Rotterdam Nucleus scenario, captured CO2 will be transported through the Port of Rotterdam to depleted gas fields offshore the Netherlands. CO2 will also be transported through further links using CCS infrastructure to facilitate the processing of undeveloped gas fields offshore UK. The Pilot case contemplates further expansion opportunities, increasing the capture clusters through additional pipelines, expanding to further gas fields and using the port of Rotterdam for CO2 shipping-hence the analysis of the other scenarios may be invaluable in the future development of CO2 networks in the EU. Finally, and an original contribution of this article is that it employs the three lawyers of energy law theoretical framework to an energy problem that was examined by an interdisciplinary research team. Furthermore, this research was developed further through two key industry stakeholder meetings with CCS experts in the EU. © The Author(s) 2018. Published by Oxford University Press on behalf of the AIPN. All rights reserved.

The underlying drivers and future development of air cargo

Scipedia content — Tue, 16 Feb 2021 12:25:26 +0100

Air cargo plays a crucial role in the air transport chain and in the globalized economy. As for other modes of transport, the demand for air cargo is a derived demand. Previous studies showed that the main determinants of air cargo demand are merchandise trade and the share of manufactures in merchandise trade. This paper aims to fill a gap in the existing literature by additionally taking the influence of air freight yields and oil prices into account when modelling the global air cargo development. Furthermore, it provides an insight into the future development of air cargo. Forecasts until 2023 are made based on a number of scenarios for the main determinants of air cargo demand. Moreover, an insight is provided into the current air cargo market, including traffic levels and different types-of actors and traffic flows. The results are useful not only for academics but also for industry stakeholders for which air cargo is an important contributor to profit and/or cash levels. (C) 2016 Elsevier Ltd. All rights reserved.

Optimal patrol scheduling of hazardous pipelines using game theory

Scipedia content — Tue, 16 Feb 2021 12:21:28 +0100

An approach based on game theory is proposed to schedule security patrolling for a pipeline system. The method proposes numbers of patrolling paths according to the risk of security incidents on the pipeline system, in order to allow the patrolling team to covering high-risk segments more than low-risk segments. Patrolling of the pipeline system was modeled mathematically, based on time and distance discretization. The overall approach also examines the presence of security countermeasures on a pipeline system, and their effects on the patrolling schedule. The application of the method is explained by an illustrative case study.

ViraPipe: Scalable Parallel Pipeline for Viral Metagenome Analysis from Next Generation Sequencing Reads

Scipedia content — Tue, 16 Feb 2021 12:20:56 +0100

Motivation Next Generation Sequencing (NGS) technology enables identification of microbial genomes from massive amount of human microbiomes more rapidly and cheaper than ever before. However, the traditional sequential genome analysis algorithms, tools, and platforms are inefficient for performing large-scale metagenomic studies on ever-growing sample data volumes. Currently, there is an urgent need for scalable analysis pipelines that enable harnessing all the power of parallel computation in computing clusters and in cloud computing environments. We propose ViraPipe, a scalable metagenome analysis pipeline that is able to analyze thousands of human microbiomes in parallel in tolerable time. The pipeline is tuned for analyzing viral metagenomes and the software is applicable for other metagenomic analyses as well. ViraPipe integrates parallel BWA-MEM read aligner, MegaHit De novo assembler, and BLAST and HMMER3 sequence search tools. We show the scalability of ViraPipe by running experiments on mining virus related genomes from NGS datasets in a distributed Spark computing cluster. Results ViraPipe analyses 768 human samples in 210 minutes on a Spark computing cluster comprising 23 nodes and 1288 cores in total. The speedup of ViraPipe executed on 23 nodes was 11x compared to the sequential analysis pipeline executed on a single node. The whole process includes parallel decompression, read interleaving, BWA-MEM read alignment, filtering and normalizing of non-human reads, De novo contigs assembling, and searching of sequences with BLAST and HMMER3 tools. Contact ilari.maarala@aalto.fi. Availability and implementation https://github.com/NGSeq/ViraPipe.

Study on the combined influence of battery models and sizing strategy for hybrid and battery-based electric vehicles

Scipedia content — Tue, 16 Feb 2021 12:19:02 +0100

This paper presents a study of the combined influence of battery models and sizing strategy for hybrid and battery-based electric vehicles. In particular, the aim is to find the number of battery (and supercapacitor) cells to propel a light vehicle to run two different standard driving cycles. Three equivalent circuit models are considered to simulate the battery electrical performance: linear static, non-linear static and non-linear with first-order dynamics. When dimensioning a battery-based vehicle, less complex models may lead to a solution with more battery cells and higher costs. Despite the same tendency, when a hybrid vehicle is taken into account, the influence of the battery models is dependent on the sizing strategy. In this work, two sizing strategies are evaluated: dynamic programming and filter-based. For the latter, the complexity of the battery model has a clear influence on the result of the sizing problem. On the other hand, a modest influence is observed when a dynamic programming strategy is followed.

A framework for demand bidding to achieve demand response objectives by EVs charging and heating loads

Scipedia content — Tue, 16 Feb 2021 12:15:30 +0100

Energy markets which are based on fixed day-ahead energy prices could face bottlenecks due to the simultaneous activation of flexible loads in the system and hence causing power imbalances and possibly also causing congestion in the distribution network. In order to mitigate these problems a suitable scheme is required to reschedule the flexible loads based on incentives for the end users for changing their demand from their day-ahead optimized demand pattern. This paper proposes a three-layer architecture of intelligent agents for scheduling of flexible loads which implies a demand bidding strategy. A real case study is considered from Nordpool spot prices for four different seasons of the year to show case the rationality of the study. Two flexible loads, Electric Vehicles (EVs) and Storage Space Heating (SSH) are considered in this scenario, while other loads are assumed non-flexible. Analysis of energy cost based on flexibility indices of loads is studied, which shows that flexibility of loads not only supports the power network capacity in congestion situation but it also benefits the consumers with cost effective use of energy. From aggregator’s perspective, the system resources are utilized optimally hence reducing the need for running extra generators and the spikes at the cheap price hours are mitigated. From the results, it is noted that the proposed bidding scheme has benefited the households up to 60% of the energy cost saving by participating in the demand response. The number of times each household wins a bid depends on the flexibility of loads and in this particular simulation scenario most of the households are able to win the bids 2 times in a day.

Automatic generation of pipelines into a 3D industrial process model

Scipedia content — Tue, 16 Feb 2021 12:14:30 +0100

Simulation has become an established technique to support the design of complex, mechatronic or cyber-physical systems. Ideally, simulations should already be performed at an early design phase before high-cost design commitments are made, and the recent advances in the digitalization of design information open possibilities for automatic generation of simulation models. However, high-fidelity simulation model building depends on accurate data. In particular, firstprinciples models are desirable source information for simulations, but such models generally are not available at an early design stage. This paper investigates the automatic generation of first-principles 3D models for piping intensive systems based on design information that is available at an early design stage, namely Piping & Instrumentation Diagrams (P&ID). An algorithm is presented for the generation of such 3D models based on machine-readable P&ID information. The main focus of the algorithm is the automatic generation of feasible pipelines into the 3D models, so that the model has sufficient information which can be exploited in further work to automatically generate high fidelity first-principles thermohydraulic simulations.

Optimisation of electric vehicles within a dynamic inductive charging infrastructure

Scipedia content — Tue, 16 Feb 2021 12:13:50 +0100

The strong interaction between electric vehicles and the charging infrastructure presents new challenges towards system-level optimization. Moreover choices between the power level, duration, and frequency of charging events can have direct impact both on energy efficiency, as well as the overall lifetime of vehicles. This paper presents a preliminary study into the optimization scheme for such systems, with the focus on an electric bus application. The results illustrate an energy saving when comparing the EMS and baseline strategy of ~ 1.6%improvement measured in kWh/km, alongside a potential cycle life prolongation factor improvement of the EMS compared to the baseline is 1.5 in average.

Total volume evaluation of high-power density non-isolated DC–DC converters with integrated magnetics for electric vehicles

Scipedia content — Tue, 16 Feb 2021 12:11:59 +0100

© The Institution of Engineering and Technology. One of the main problems in electric vehicles is the volume of their electrical systems because their bulky components carry additional mass and high cost to the total system. On this topic, interleaving-phases and magnetic coupling techniques have been reported as effective methods for increasing the power density of the DC-DC converters that work between the storage unit and the motor inverter. In that sense, a volume assessment of these topologies would provide a better understanding of the problems to be faced when an electric power train is designed. In this paper, a volume modelling methodology is introduced with the purpose of comparing four different DC-DC converters: Single-Phase Boost, Two-Phase Interleaved with non-coupled inductors, Loosely Coupled Inductor (LCI), and Integrated Winding Coupled Inductor (IWCI). The analysis considers the volume of magnetic components, power devices (conventional and next-generation), cooling devices and capacitors. The methodology can be used as a part of an optimization procedure to minimize the volume of DC-DC converters. Conclusively, LCI and IWCI were found effective to miniaturize power converters with a power density of 8.4 W/cc and 9.66 W/cc, respectively. Moreover, a maximum efficiency of 98.04% and 97.61% was obtained for a 1kW LCI and IWCI prototypes, respectively. ispartof: IET POWER ELECTRONICS vol:10 issue:14 pages:2010-2020 status: published

Effect of Multitasking on Simulator Sickness and Performance in 3D Aerodrome Control Training

Scipedia content — Tue, 16 Feb 2021 12:01:04 +0100

WOS: 000424708100003

Background. Air traffic controllers need to use their cognitive resources to cope with multiple tasks while monitoring air traffic. They are trained through advanced 3D simulators; however, they might demonstrate simulator sickness symptoms during this training. The relationship between multitasking and simulator sickness and the influence of different tasks on these variables can be investigated to inform further training practices for an efficient traffic monitoring. Purpose. The purpose of this quasi-experimental research was to explore the influence of different working positions and multitasking scenarios on simulator sickness and performance in 3D Aerodrome Control Training. Method. Thirteen undergraduate students from a civil aviation school participated in a time-series experimental design. Nausea, disorientation and oculomotor disturbances were measured before and after conducting different multitasking scenarios in an aerodrome control simulator. A 20-item simulation performance scale was also used. Performance differences and the relationship between simulator sickness and performance were addressed through parametric tests. Results. Findings revealed that tower-ground positions created higher levels of nausea. Performance scores varied in different scenarios. Simulator sickness was higher in females. Total sickness correlated negatively with performance in all scenarios. Conclusion. Certain tasks have different influences on both simulator sickness and performance. Concurrent multitasking seems to trigger simulator sickness further. The degree of simulator adaptation, test anxiety and physiological measures of the process should be considered in further research.

Analysis, control and design of speed control of electric vehicles delayed model:multi-objective fuzzy fractional-order PI λD μ PIλDμ controller

Scipedia content — Tue, 16 Feb 2021 11:59:18 +0100

The purpose of this study is to suggest an optimal multi-objective fuzzy fractional-order PIλDμPIλDμ controller (MOFFOPID) for the speed control of EV systems with time-delay. It is presumed that while the EV is in movement, the armature winding resistance of the direct current (DC) motor varies with time due to temperature changes and this makes it impossible to develop an accurate dynamic model for an EV system. Consequently, in order to have a fast and accurate tracking of the set-point, besides a smooth control signal, a new multi-objective stochastic optimisation is used for the online adjustment of the parameters of MOFFOPID controller. Moreover, a comparison is made between the results of the current study and those of some of the most recent studies on the same topic, which have used online multi-objective PI and online multi-objective fuzzy PI, to assess the efficiency of the suggested controller. Finally, the experimental results based on a TMS320F28335 DSP are implemented on a DC motor to verify the effectiveness of the proposed MOFFOPID controller in controlling the speed of the DC motor which has non-linear features. The results of the simulation confirm the desirable performance of suggested controller.

Multi-agent transactive energy management system considering high levels of renewable energy source and electric vehicles

Scipedia content — Tue, 16 Feb 2021 11:53:20 +0100

The future smart grids (SGs) consist of considerable amount of renewable energy sources (RESs), electrical vehicles (EVs), and energy storage systems (ESSs). The uncertainties associated with EVs and uncontrollable nature of RESs have magnified voltage stability challenges and the importance of an effective energy management system (EMS) in SGs as a practical solution. This study presents a multi-agent transactive energy management system (TEMS) to control demand and supply in the presence of high levels of RESs and EVs, and maximises profit of each participant in addition to satisfying voltage regulation constraints. For this purpose, a real-time pricing is considered based on Cournot oligopoly competition model for demand and merit order effect for production to compensate RESs' fluctuations in real time by an indirect control method. Simulations are conducted in the modified IEEE 37-bus test system with 1141 customers, 670 EVs, two solar plants, four wind turbines, and one ESS. The results show that the proposed multi-agent TEMS can indirectly control EVs, elastic loads, and ESSs to balance the RESs oscillation, minimise customers cost, and regulate voltage in a real-time manner. "p"QC 20171204

Simulating crowd evacuation with socio-cultural, cognitive, and emotional elements

Scipedia content — Tue, 16 Feb 2021 11:47:37 +0100

In this research, the effects of culture, cognitions, and emotions on crisis management and prevention are analysed. An agent-based crowd evacuation simulation model was created, named IMPACT, to study the evacuation process from a transport hub. To extend previous research, various socio-cultural, cognitive, and emotional factors were modelled, including: language, gender, familiarity with the environment, emotional contagion, prosocial behaviour, falls, group decision making, and compliance. The IMPACT model was validated against data from an evacuation drill using the existing EXODUS evacuation model. Results show that on all measures, the IMPACT model is within or close to the prescribed boundaries, thereby establishing its validity. Structured simulations with the validated model revealed important findings, including: the effect of doors as bottlenecks, social contagion speeding up evacuation time, falling behaviour not affecting evacuation time significantly, and travelling in groups being more beneficial for evacuation time than travelling alone. This research has important practical applications for crowd management professionals, including transport hub operators, first responders, and risk assessors.

Battery pack state estimation algorithms – Model based development and estimation

Scipedia content — Tue, 16 Feb 2021 11:37:50 +0100

Model based development methodologies have strong potential in reducing development effort of complex automotive systems. This paper presents a model based development methodology used to develop battery state estimation algorithms, and steps through all the steps required for this. The benefits of the mixed simulation and testing methodology are outlined using a State of Charge estimation algorithm development example. Overall, this development methodology leads to safer, more efficient and more affordable battery packs, enabling faster market update of electric vehicles.

Quantifying the effectiveness of ITS in improving safety of VRUs

Scipedia content — Tue, 16 Feb 2021 11:36:13 +0100

This paper presents the results of a safety impact assessment, providing quantitative estimates of the safety impacts of ten intelligent transport systems (ITS) which were designed to improve safety, mobility and comfort of vulnerable road users (VRUs). The evaluation method originally developed to assess safety impacts of ITS for cars was now adapted for assessing safety impacts of ITS for VRUs. The main results of the assessment showed that nine ITS included in the quantitative safety impact assessment affected traffic safety in a positive way by preventing fatalities and injuries. At full penetration the highest effects were obtained for Pedestrian and Cyclists Detection System + Emergency Braking (PCDS+EBR), VRU Beacon System (VBS) and Intersection Safety (INS). The estimates for PCDS+EBR showed the maximum reduction of 7.5% on all road fatalities at full penetration, which comes down to an medium estimate of around 1,900 fatalities saved per year in the EU-28 when applying the 2012 accident data and 100% penetration rate. The results regarding future scenarios showed the highest effects in number of reduced fatalities per system in the European Union (EU)-28 in 2030 for PCDS+EBR (-200 fatalities), Blind Spot Detection (BSD) (-22 fatalities), INS (-20 fatalities) and VBS (-11 fatalities). © 2017 The Institution of Engineering and Technology.

Battery-ultracapacitor electric vehicles

Scipedia content — Tue, 16 Feb 2021 11:31:50 +0100

Energy management strategies for an electric vehicle (EV) with multiple power sources have been widely described in literature. The investigated energy sources are batteries, ultracapacitors, fuel cells, flywheels and solar panels. The management strategy decides how to combine two or more sources in an optimal way. However, the behavior of these sources and also the behavior of the electric drives depend on their temperature. Moreover, the temperature can have extreme values in automotive applications and affect the energy management task. In this paper, to investigate the temperature effect on battery/ultracapacitor powered EV, temperature dependent models are presented for these storage components, as well as for the drive train components itself: power electronics and motor. The average motor iron loss and ultracapacitor loss tend to decrease with increasing temperature, while the average motor copper loss and power electronics loss tend to increase with increasing temperature. These two opposing trends cause the total loss of the drive train to have a rather small variation with temperature for the considered EV and in the considered temperature range. By consequence, the energy management strategy of the EV does not have to depend on the temperature in order to obtain maximal efficiency. (C) 2017 Elsevier Ltd. All rights reserved.

Social Network Based Crowd Sensing for Intelligent Transportation and Climate Applications

Scipedia content — Tue, 16 Feb 2021 11:30:29 +0100

In recent years, the growing prevalence of social networks makes it possible to utilize human users as sensors to inspect city environment and human activities. Consequently, valuable insights can be gained by applying data mining techniques to the data generated through social networks. In this work, a practical approach to combine data mining techniques with statistical analysis is proposed to implement crowd sensing in a smart city. A case study to analyze the relationship between weather conditions and traffic congestion in Beijing based on tweets posted on Sina Weibo platform is presented to demonstrate the proposed approach. Following the steps of data pre-processing and topic determination, we applied Granger Causality Test to study the causal relationships between weather conditions, traffic congestion and human outdoor activity. The mediation analysis is also implemented to verify human outdoor activity as a mediator variable significantly carrying the influence of good weather to traffic congestion. The result demonstrates that outdoor activity serves as a mediator transmitting the effect of good weather on traffic congestion. In addition, the causes of negative emotion are also studied.

Safety, mobility and comfort assessment methodologies of intelligent transport systems for vulnerable road users

Scipedia content — Tue, 16 Feb 2021 11:29:23 +0100

Introduction: This paper describes the modification and development of methodologies to assess the impacts of Intelligent Transport Systems (ITS) applications for Vulnerable Road users (VRUs) in the domains of safety, mobility and comfort. This effort was carried out in the context of the VRUITS project whose aim was to produce results at the EU-28 level. Methods: An existing safety methodology was modified to take into account specific VRU aspects. The mobility and comfort assessments methodologies were developed in the project. Results: The safety, mobility and comfort methodologies were applied to ten ITS applications for VRUs. The first innovation determined how the nine safety mechanisms for ex-ante analysis of ITS applications, including direct and indirect effects, can incorporate the important characteristics of the VRU groups (pedestrians, cyclists and Power-Two-Wheeler riders) in the analysis. The second innovation developed a conceptual model for mobility and comfort. Thirdly, the estimation of quantitative effects, using literature, empirical findings and expert judgement, was developed. Conclusions: The new safety, mobility and comfort assessment methodologies were applied to calculate the respective effects for VRUs using ITS. These results are ex-ante findings, as very few to no empirical results for ITS applications for VRUs are available. In order to improve the accuracy of the estimates, there is a need for better standardized data and at the European level. Finally, validation of the methods could be done in the future field operational tests focusing on measuring user behavior. © 2017, The Author(s).

Document type: Article

Road transport productivity in the sixteenth-century Low Countries : the case of Brabant, 1450-1650

Scipedia content — Tue, 16 Feb 2021 11:28:29 +0100

Though there is a consensus that transport plays a central role in economic development, for the period before the eighteenth century there is a lack of strategic information for assessing the importance of road transport productivity changes in economic development. Transport prices in particular are crucial missing pieces of the puzzle. Sources rarely reveal information that meets the standards of reliable price history. However, it is possible to create a reliable transport price series on the basis of the transport of millstones to ducal mills in Brabant. Assessing the impact of the transport productivity changes' that can be inferred from this transport price series is a hazardous exercise. Moreover, as Masschaele has observed, land transport prices closely match general agricultural price trends. Land transport was essentially an agricultural service, determined both by cost (especially horse provender) and income effects. Transport price inflation was not demand-led. However, while transport did not impede urbanization and economic growth, conversely, in sixteenth-century Brabanta highly urbanized region that experienced considerable growth in the volume of land transportno significant land transport productivity gains were achieved.

A problem-solving model from the RESTRAIL project

Scipedia content — Tue, 16 Feb 2021 11:24:21 +0100

Suicides and trespassing accidents result in more than 3800 fatalities in Europe, representing 88% of all fatalities occurring within the EU railway system. This paper presents a problem-solving model, which consists of a multistep approach structuring the analysis of a suicide or trespass-related problem on the railways. First, we present the method used to design, evaluate and improve the problem-solving model. Then we describe the model in detail: it comprises six steps with several subsequent actions, and each action is approached through a checklist of prompting questions and possible answers. At the end, we discuss the added value of this model for decision makers and its usability in the selection of optimal prevention measures.

Adaptive traffic signal control with actor-critic methods in a real-world traffic network with different traffic disruption events

Scipedia content — Tue, 16 Feb 2021 11:22:51 +0100

The transportation demand is rapidly growing in metropolises, resulting in chronic traffic congestions in dense downtown areas. Adaptive traffic signal control as the principle part of intelligent transportation systems has a primary role to effectively reduce traffic congestion by making a real-time adaptation in response to the changing traffic network dynamics. Reinforcement learning (RL) is an effective approach in machine learning that has been applied for designing adaptive traffic signal controllers. One of the most efficient and robust type of RL algorithms are continuous state actor-critic algorithms that have the advantage of fast learning and the ability to generalize to new and unseen traffic conditions. These algorithms are utilized in this paper to design adaptive traffic signal controllers called actor-critic adaptive traffic signal controllers (A-CATs controllers). The contribution of the present work rests on the integration of three threads: (a) showing performance comparisons of both discrete and continuous A-CATs controllers in a traffic network with recurring congestion (24-h traffic demand) in the upper downtown core of Tehran city, (b) analyzing the effects of different traffic disruptions including opportunistic pedestrians crossing, parking lane, non-recurring congestion, and different levels of sensor noise on the performance of A-CATS controllers, and (c) comparing the performance of different function approximators (tile coding and radial basis function) on the learning of A-CATs controllers. To this end, first an agent-based traffic simulation of the study area is carried out. Then six different scenarios are conducted to find the best A-CATs controller that is robust enough against different traffic disruptions. We observe that the A-CATs controller based on radial basis function networks (RBF (5)) outperforms others. This controller is benchmarked against controllers of discrete state Q-learning, Bayesian Q-learning, fixed time and actuated controllers; and the results reveal that it consistently outperforms them.

Predictive battery thermal management strategy for fast charging electric vehicles - Type the subtitle of the paper

Scipedia content — Tue, 16 Feb 2021 11:18:22 +0100

Battery thermal management is essential to efficienct and safe operation of Li-ion batteries, particularly in challenging applications such as fast charging. This work proposes a thermal management control framework based on MPC. The novelty of this approach resides in the focus on incorporating disturbance prediction into the control decision. Simulations show that this methodology allows for (1) lower peak and mean battery temperatures during fast charging for a similarly sized battery thermal management system; or (2) battery thermal management system downsizing for similar thermal performance.

From the testing to the deployment of self-driving cars

Scipedia content — Tue, 16 Feb 2021 11:14:57 +0100

Understanding Effectiveness Skepticism

Scipedia content — Tue, 16 Feb 2021 11:11:36 +0100

Policy makers have proposed various incentive programs to curb consumption-related problems, such as traffic congestion and carbon emissions. While experts consider such programs effective in reducing those problems, consumers are more skeptical. Although this "effectiveness skepticism" is currently viewed as an important cause of public opposition, the authors argue that it may also arise as a consequence of opposition. Specifically, consumers oppose policies they consider personally unattractive or unfair. This opposition motivates them to also be skeptical about the potential effectiveness of such policies. Three studies that include a variety of methods, policies, and samples provide empirical support for this reasoning: perceptions of expected effects can be biased by consumers' perceptions of personal attractiveness and fairness. In line with this causal ordering, the authors find that offering optimistic effectiveness estimates, although successful in reducing effectiveness skepticism, did not boost policy support. Policy makers aiming to boost support prior to implementation should thus not only communicate a policy's effectiveness, but also address other causes of opposition.

How Strangers Initiate Conversations. Interactions on Public Trains in Germany

Scipedia content — Tue, 16 Feb 2021 11:11:23 +0100

This article considers how strangers who use public transportation initiate conversations and how disruptions of the transportation system affect interactions among strangers. How conversations are initiated has rarely been discussed in the literature because the majority of research takes the initiation of talk for granted. Building on Goffman, the article tests two hypotheses that explain how strangers initiate conversations. The first hypothesis states that travelers rely on interactional rituals if they have to talk with others because of a rule against opening talk with strangers, a rule that can be relaxed if travelers are faced with disruptive events. The second hypothesis states that a conversation can be initiated without introductory remarks if a traveler’s focus of attention is discernible to another traveler, irrespective of the circumstances travelers find themselves in. I argue that the latter hypothesis better explains how strangers initiate conversations and discuss how this finding may be generalized.

Health Impact Assessment of Cycling Network Expansions in European Cities

Scipedia content — Tue, 16 Feb 2021 11:10:20 +0100

Background Active transport (i.e. walking and cycling for transport) can provide substantial health benefits by increasing levels of physical activity (PA) and help reduce transport-associated emissions. Our aim was to conduct a health impact assessment (HIA) of cycling networks expansions in seven diverse European cities (Antwerp, Barcelona, London, Orebro, Rome, Vienna, Zurich) that form part of the Physical Activity through Sustainable Transport Approaches (PASTA) project. We modeled the association between cycling network distance (km) and cycling mode share (%) and estimated health impacts of the expansion of cycling networks. Methods Cycling network distances were computed for 168 European cities using OpenStreetMap data for designated cycling ways. Cycling mode share was available through the European Platform on Mobility Management. We performed a non-linear least square regression to assess the relationship between cycling network and cycling mode share. We performed a quantitative HIA for five different scenarios (S) (10% (S1); 50% (S2); 100% (S3), Go-Orebro (S4) and All-streets (S5)) assessing how an expansion of the cycling network would lead to an increase in cycling mode share and estimated associated mortality impacts thereof. We quantified mortality impacts in terms of changes to PA levels, exposure to air pollution and traffic incidents for the cyclist. Results Our results suggest that the cycling network may contribute to a cycling mode share of up to 25% in European cities. A cycling network as that of Orebro (S4; 255 km/100,000 persons) produced greatest health benefits through increases in cycling for London with 646 (95% CI: 397;1012) annual deaths avoided, followed by Rome (224; 95% CI: 133;359), Barcelona (162; 95% CI: 103;248), Vienna (82; 95% CI: 47;133), Zurich (27; 95% CI: 16;42) and Antwerp (3; 95% CI: 2;6). If all 168 European cities achieved a cycling mode share of 25% over 16,000 deaths (95% CI: 9,861;25,763) could be avoided each year. The largest cost-benefit ratios were found for the 10% increase in cycling network (S1) suggesting it to be most cost-effective (Rome € 40:1; Barcelona € 20:1; Zurich € 16:1; Vienna € 11:1, London € 3:1). Conclusions Especially in cities with a currently low cycling mode share, expansion of cycling networks may promote increases in cycling mode share. Increases in cycling mode share were estimated to provide considerable health benefits in European cities.

Optimum aggregation of geographically distributed flexible resources in strategic smart-grid/microgrid locations

Scipedia content — Tue, 16 Feb 2021 11:04:39 +0100

This study determines optimum aggregation areas for a given distribution network considering spatial distribution of loads and costs of aggregation. An elitist genetic algorithm combined with a hierarchical clustering and a Thevenin network reduction is implemented to compute strategic locations and aggregate demand within each area. The aggregation reduces large distribution networks having thousands of nodes to an equivalent network with few aggregated loads, thereby significantly reducing the computational burden. Furthermore, it not only helps distribution system operators in making faster operational decisions by understanding during which time of the day will be in need of flexibility, from which specific area, and in which amount, but also enables the flexibilities stemming from small distributed resources to be traded in various power/energy markets. A combination of central and local aggregation scheme where a central aggregator enables market participation, while local aggregators materialize the accepted bids, is implemented to realize this concept. The effectiveness of the proposed method is evaluated by comparing network performances with and without aggregation. For a given network configuration, steady-state performance of aggregated network is significantly accurate ( ≈ ± 1.5% error) compared to very high errors associated with forecast of individual consumer demand.

Transport indicator analysis and comparison of 151 urban areas, based on open source data

Scipedia content — Tue, 16 Feb 2021 10:56:10 +0100

Introduction The accurate analysis and comparison of transport indicators from a large variety of urban areas can help to evaluate the performance of different adopted transport policies. This paper attempts to determine important transport and socio-economic indicators from 151 urban areas and 51 countries, based on comparable, directly observable open-source data such as OpenstreetMap (OSM) and the TomTom database. Analysis This is the first, systematic indicator-analysis using recent, open source data from different urban areas around the world. The indicator road kilometers per person, sometimes cited as infrastructure accessibility is calculated by processing OSM data. Information on congestion levels have been taken from the TomTom database and socio-economic data from various, publicly accessible databases. Relations between indicators are identified through correlations and regression models are calibrated, quantifying the relation between transport infrastructure and performance indicators. Three sub-categories of cities with different population sizes (small cities, large cities and metropolises) are defined and studied individually. In addition, a qualitative analysis is performed, putting five different indicators into relation. Results & Conclusions The main results reconfirm previous findings but with a larger sample size and more comparable data. Good correlation values between infrastructure accessibility, socio-economic indicators, and congestion levels are demonstrated. It is shown that cities with higher GDP have generally built more infrastructure which in turn reduces their congestion levels. In particular, for cities with low population density (above approximately 1500 inh. Per sq.km), more roads per inhabitant lead to lower congestion levels; cities with high population density have in general lower congestion levels if the rail infrastructure per person ratio is high. Furthermore, these cities increasing railways per person is more effective in reducing congestions than increasing road length per person.

Document type: Article

Investigation of impact forces on pipeline by submarine landslide using material point method

Scipedia content — Tue, 16 Feb 2021 10:52:17 +0100

Quantitative assessment of impact forces by submarine landslide is significant for the safe operation of pipelines that must cross potential runout paths. In this paper, the transient process of a submarine landslide impacting a pipeline is modelled using the material point method (MPM) with an enhanced contact algorithm. For simplicity, the partially-embedded pipeline is assumed to be fixed in space. The Herschel-Bulkley rheological model is incorporated to reflect the dependence of the undrained shear strength of the sliding mass on the shear strain rate. The behaviour of the mass flowing over the pipe was reproduced by allowing separation between the pipe and the sliding mass. The horizontal impact forces predicted by the MPM are verified by comparison with those estimated using a computational fluid dynamics approach. The impact forces are interpreted with a hybrid model considering the combined effects due to the soil's inertia, its shear strength, and also the asymmetric static pressure of the sliding material. The coefficients for the three terms are retrieved by a best-fit to the results of an extensive parametric study. The effect of the projected height of the pipe above the seabed is also investigated.

Highways and firm performance in the logistics industry

Scipedia content — Tue, 16 Feb 2021 10:44:40 +0100

Using detailed geo-referenced data we analyse the effects of highway development on firm level performance in the Spanish logistics sector. To address potential endogeneity issues we carry out panel data analysis together with instrumental variable estimation. Results show that highways have significant implications for logistics' firm performance, although with important spatial heterogeneity. For urban logistics firms, a reduction in the distance to their nearest highway increases their productivity performance. In contrast, for rural logistics firms, improvements in highway access show a positive impact on employment growth but have also led to a reduction in productivity growth for those rural logistics firms that remained outside highway corridors.

Peer reviewed

Optimization of Charge/Discharge Coordination to Satisfy Network Requirements Using Heuristic Algorithms in Vehicle-to-Grid Concept

Scipedia content — Tue, 16 Feb 2021 10:35:55 +0100

Image thresholding is the most crucial step in microscopic image analysis to distinguish bacilli objects causing of tuberculosis disease. Therefore, several bi-level thresholding algorithms are widely used to increase the bacilli segmentation accuracy. However, bi-level microscopic image thresholding problem has not been solved using optimization algorithms. This paper introduces a novel approach for the segmentation problem using heuristic algorithms and presents visual and quantitative comparisons of heuristic and state-of-art thresholding algorithms. In this study, well-known heuristic algorithms such as Firefly Algorithm, Particle Swarm Optimization, Cuckoo Search, Flower Pollination are used to solve bi-level microscopic image thresholding problem, and the results are compared with the state-of-art thresholding algorithms such as K-Means, Fuzzy C-Means, Fast Marching. Kapur's entropy is chosen as the entropy measure to be maximized. Experiments are performed to make comparisons in terms of evaluation metrics and execution time. The quantitative results are calculated based on ground truth segmentation. According to the visual results, heuristic algorithms have better performance and the quantitative results are in accord with the visual results. Furthermore, experimental time comparisons show the superiority and effectiveness of the heuristic algorithms over traditional thresholding algorithms.

Effect of dietary supplementation with carnosic acid or vitamin E on animal performance, haematological and immunological characteristics of artificially reared suckling lambs before and after road transport

Scipedia content — Tue, 16 Feb 2021 10:35:39 +0100

13 páginas, 6 tablas.

To elucidate the influence of dietary carnosic acid (CA) and vitamin E on animal performance, immune response indicators and haematological parameters before and after transport stress, 24 lambs were individually fed ad libitum with milk replacer (MR) using an auto-feeder. Once daily the lambs received MR alone (Group CON, n = 8), MR + 0.096 g CA/kg live weight (LW) (Group CARN, n = 8) or MR + 0.024 g of α-tocopheryl acetate per kg LW (Group VitE, n = 8). After reaching the target slaughter weight (12 ± 0.5 kg), blood samples were collected to measure haematological and immunological parameters. Then, lambs were subjected to 4-h road transport and blood samples were collected again for haematological assessment. The animals were subsequently slaughtered. Before road transport, dietary CA supplementation promoted a descent of circulating white blood cells (WBC), red blood cells (RBC), haematocrit and haemoglobin concentration when compared with Groups CON and VitE (p " 0.05), but it did not affect production of cytokines by blood mononuclear cells. Road transport did not affect either RBC or haematocrit significantly. Nevertheless, transport affected leucocyte profile similarly in all the treatments, increasing granulocytes and monocytes proportions and decreasing lymphocytes. In contrast, after transport, WBC was increased in Group CARN, reaching similar values than Groups CON and VitE. However, under conditions of the present study, those modifications did not influence animal performance or immunity parameters of artificially reared suckling lambs.

Peer Reviewed

Technologies and control for sustainable transportation

Scipedia content — Tue, 16 Feb 2021 10:33:56 +0100

The scarcity of natural resources, rising traffic congestion and air pollution have increased the interest for sustainable transportation systems. The transition to more societally, environmentally and economically sustainable transportation can be achieved through various means, including adoption of alternative fuel and vehicle technologies, consolidation of logistic flows and services, and energy efficient transit and traffic operations. To assess the impact of different technologies and control systems with respect to both traditional performance measures and sustainability indicators new methods and tools are required. This Special Issue contains a selection of the state-of-the-art research on mathematical models, methodologies, quantitative analyses, and advanced applications that address the impacts of these technologies and control for the sustainability of transportation systems, services and components—across all modes of transportation. After several rounds of peer review, we selected ten papers for publication in this special issue. The first four papers study novel routing and scheduling strategies to support different sustainable transportation concepts.

Optimisation of support stiffness at railway crossings

Scipedia content — Tue, 16 Feb 2021 10:24:48 +0100

Turnouts are a key element of the railway system. They are also the part of the system with the highest number of degradation modes and associated failures. There are a number of reasons for this, including high dynamic loads resulting from non-uniform rail geometry and track support stiffness. The main aim of this study is to propose a methodology to optimise the pad stiffness along a crossing panel in order to achieve a decrease in the indicators of the most common failure modes. A three-dimensional vehicle/track interaction model has been established, considering a detailed description of the crossing panel support structure. A genetic algorithm has been applied to two main types of constructions, namely direct and indirect fixing, to find the optimum combinations of resilient pad characteristics for various cases of travelling direction, travelling speed and support conditions.

Symbolic boundary making in super-diverse deprived neighbourhoods

Scipedia content — Tue, 16 Feb 2021 10:24:35 +0100

Neighbourhood-based research on the rise of super-diverse cities has mostly focussed on the implications of living in super-diverse neighbourhoods for individual relations, and paid little attention to processes of group formation. This paper focuses on how residents of super-diverse neighbourhoods identify social groups. Drawing on the concept of symbolic boundary making, it provides insights into how residents draw, enact and experience boundaries. Using the results of in-depth interviews with residents in Antwerp and Rotterdam, we show that super-diversity complexifies but does not counteract group formation. Residents draw multiple, interrelated symbolic boundaries along ethnic, class and religious lines and lines based on length of residence, which are sometimes used interchangeably. We also show that group boundaries are dynamic and constantly (re-)created. Finally, we show that discursive boundaries do not necessarily lead to less social contact across these boundaries, thus illustrating that symbolic boundaries do not always result in segregated social patterns.

Estimating the relative cost of track damage mechanisms: combining economic and engineering approaches

Scipedia content — Tue, 16 Feb 2021 10:20:10 +0100

This paper proposes a new, two-stage methodology to estimate the relative marginal cost of different types of vehicles running on the rail infrastructure. This information is important particularly where the infrastructure managers wish to differentiate the track access charges by vehicle type for the purpose of incentivizing the development and use of more track-friendly vehicles. EU legislation requires that the European infrastructure managers set the access charges based on the incremental (marginal) cost of the running trains on their networks. The novelty of the approach derives from the combination of: (1) engineering simulation methods that estimate the track damage caused by the rail vehicles; and (2) econometric methods that estimate the relationship between the actual maintenance costs and the different damage mechanisms. This two-stage approach fills an important gap in the literature, given the limitations of the existing “single-stage” engineering or econometric approaches in obtaining the relative marginal costs for different types of damage. The authors demonstrate the feasibility of the method using 45 track sections from Sweden, for which the data on maintenance costs are available together with relevant track and vehicle data for 2012 (supplied by the Swedish Transport Administration). The authors demonstrate the feasibility of producing summary, section-level damage measures for the three damage mechanisms (wear, rolling contact fatigue, and track settlement), which can be taken forward to the second stage. The econometric results of the second stage indicate that it is possible to obtain sensible relationships between cost and the different damage types, and thus produce relative marginal costs by the damage mechanism and in turn the vehicle type. Based on this feasibility study, tracksettlement has been found to be the most expensive (in terms of maintenance cost) of the three mechanisms, followed by the rolling contact fatigue and then the wear. Future applications should focus on larger datasets in order to produce the required degree of precision on the estimation of the marginal cost.

Heuristic Optimization of EV Charging Schedule Considering Battery Degradation Cost

Scipedia content — Tue, 16 Feb 2021 10:17:33 +0100

It is expected that electric vehicles (EVs) will be important part of smart gird, not only in form of load but also as distributed energy source in Vehicle to Grid (V2G) system. As increase of EVs integration, V2G contributes to improve flexibility, reliability and stability of grid by providing ancillary services. These services, however, could accelerate degradation of battery whose price is almost half of EV. Thus, battery degradation cost must be considered while scheduling of EV charging. In this paper, a battery degradation cost model of EV lithium-ion batteries was incorporated in the optimal charging schedule of 400 EVs. EVs are located to 33 bus system in order to consider network losses in calculations. Heuristic algorithms such as Genetic Algorithm (GA), Differential Evolution (DE), Particle Swarm Optimization (PSO) and Artificial Bee Colony (ABC) are used for solving the associated optimization problem. The objective function aims to maximize user profit under dynamic pricing. Also, distribution system and EVs constraints are considered during optimization. The numerical results illustrate that each of the used heuristic algorithms able to mitigate peak loads and improve voltage levels. GA presents the most profitable charging scheduling in terms of EV owners. DOI: http://dx.doi.org/10.5755/j01.eie.24.6.22283

A metaheuristic for the time-dependent pollution-routing problem

Scipedia content — Tue, 16 Feb 2021 10:04:33 +0100

We propose a metaheuristic for the Time-Dependent Pollution-Routing Problem, which consists of routing a number of vehicles to serve a set of customers and determining their speed on each route segment with the objective of minimizing the cost of driver’s wage and greenhouse gases emissions. The vehicles face traffic congestion which, at peak periods, significantly restricts vehicle speeds and leads to increased emissions. Our algorithm is based on an adaptive large neighborhood search heuristic and uses new removal and insertion operators which significantly improve the quality of the solution. A previously developed departure time and speed optimization procedure is used as a subroutine to optimize departure times and vehicle speeds. Results from extensive computational experiments demonstrate the effectiveness of our algorithm.

Economic viability of electric roads compared to oil and batteries for all forms of road transport

Scipedia content — Tue, 16 Feb 2021 09:55:25 +0100

The aim in this paper is to evaluate the economic viability of electric vehicles that are supplemented by electric roads (eRoads), instead of using conventional diesel, petrol, and battery electric vehicles (BEVs). The battery is the most expensive component of an electric vehicle, so the premise of this paper is to reduce the size of the battery, and thereby significantly reduce the cost, by installing a series of electric roads for long-distance journeys. Denmark is used here as case study to ensure the assumptions reflect a real-world case when comparing petrol, diesel, BEVs, and eRoads. The results suggest that eRoads are a cheaper method of electrifying road transport than BEVs, which is an important finding, since electrification is widely believed to be the cheapest method for decarbonising the transport sector in the coming decades. Furthermore, if fuel and vehicle prices evolve as predicted between now and 2050, then eRoads are also a cheaper form of road transport than diesel and petrol, primarily due to increasing oil prices and decreasing battery costs. By implementing eRoads, it is also possible to electrify heavy-duty transport such as buses and trucks, which results in even more energy savings and reductions in carbon dioxide emissions. Keywords: eRoad, Sustainable transport, Electric car, Electric vehicle, Electric road

Hedonic value of high-speed rail services: Quantitative analysis of the students’ domestic tourist attractiveness of the main Italian cities

Scipedia content — Tue, 16 Feb 2021 09:51:19 +0100

High-Speed Rail (HSR) is a transport mode that operates significantly faster than traditional services, using integrated and specialized rolling stock, and often dedicated tracks. These rapid transit services have profoundly impacted mobility habits on medium-long range journeys, and have also brought about social, economic, and environmental changes in the geographical areas involved. HSR has become a successful “brand”, including not only faster trains, but also a number of other on-board services that increase rail attractiveness (e.g. restaurants, wi-fi connection, free newspapers, cinema, business areas and relaxation lounges). Starting from these considerations, in this research we investigated the conjecture according to which a traveler, in choosing an HSR service to reach a destination (against a traditional rail service, or other competing transport modes), is not only influenced by its original peculiarity as a “faster train” service, but also takes into account the presence of all the “hedonic” characteristics of the service. That said, the literature in transportation modeling has yet to analyze the impact of hedonic quality on travelers’ behavior by quantifying whether and to what extent it increases their propensity to use HSR services. Aim of this research was twofold: i) to quantify, for the first time in the literature, the hedonic value of an HSR service related to a domestic tourist trip, as compared to more conventional levels of service and attractiveness attributes; ii) investigate the domestic tourist attractiveness of the main Italian cities, evaluating which attributes influence the perception of a city as a domestic tourist destination. The application case study consists in the supply of current rail services (HSR vs. traditional) between the 11 main Italian cities in terms of tourist destination. On the basis of an RP&SP survey, carried out among university students at national scale, a binomial logit model was specified with serial correlation in residuals, estimating whether or not the cities in the panel were perceived as possible destinations for a domestic tourist trips made by train. The estimation results show that city-specific attractiveness attributes (entertainment and restaurant rate; number of sites of interests; crime rate), and level of services variables (e.g. travel time and cost; HSR brand ) significantly influence the perception of a city as a possible destination for a domestic tourist trip by train. Furthermore, the average monetary value for the “pure preference” for the HSR brand (faster trains, high frequency, and on-board services) is about 22 Euros/trip, while the hedonic value relative only to on-board services is about 12 Euros/trip , underlining that the “faster train” is only one of the perceived attributes of HSR services. Overall, the willingness to pay for an HSR ticket is up to 40% greater than that for a traditional one. Furthermore, tourists are willing to spend 2.2 h more travelling on an HSR train to reach their destinations. The estimation results show that there is also a “distance traveled effect”; the pure preference for HSR services increases in value from 9 Euros/trip to 13 Euros/trip (+44%) for distances traveled greater than 400 km. If confirmed, these results allow the conclusion to be drawn that the “catchment area” of cities on HSR networks is larger than that served by traditional rail.

A Novel Rerouting Planning Model for the Terminal Arrival Routes under the Influence of Convective Weather

Scipedia content — Mon, 15 Feb 2021 12:34:58 +0100

Under convective weather conditions, aircraft rerouting in terminal airspace is essential to ensure flight safety and reduce air traffic delays. Traditional air traffic rerouting approaches do not combine convective weather information using radar image recognition with controller workload, additional fuel consumption, delay loss, time cost, and route length at terminal airspace in tactical ATFM phase for exact rerouting decision. In accordance with the safety and economic principles of the route network in terminal airspace and in consideration of the changes in the speed and height of aircraft in terminal airspace, a multiobjective rerouting planning model is established in this study for terminal airspace under convective weather conditions in tactical air traffic flow management phase. Then traffic simulation is conducted to analyze the capacity and delays of the rerouting in the approach path in Shanghai terminal area. Experimental results indicate that this model can increase airspace capacity and operational efficiency of air traffic compared with the traditional air traffic rerouting approaches.

Document type: Article

The Virtual Driving Coach - design and preliminary testing of a predictive eco-driving assistance system for heavy-duty vehicles

Scipedia content — Mon, 15 Feb 2021 12:34:19 +0100

The commercial vehicle sector is characterized by high competitive pressure. Fuel consumption is one major factor that influences the transport efficiency and competitiveness of logistics companies. Therefore, an eco-driving assistance system (EDAS) is developed in order to support the driver in sustainably maintaining an efficient driving style—the Virtual Driving Coach (ViDCo). In this paper, we describe the design and development process of ViDCo as well as results of the first steps of evaluation and preliminary testing. An EDAS is developed that uses knowledge of infrastructure based on digital maps in order to proactively and predictively provide the driver with driving advice. The system’s algorithms are structured within the modules “situation detection”, “driving error detection”, and “message filtering and prioritization”. The evaluation of ViDCo comprises preliminary field-testing on public roads as well as a driving simulator experiment. Driving tests show that the Virtual Driving Coach is capable of enhancing fuel efficiency for commercial vehicles in real-world scenarios. The results of the driving simulator experiment indicate a positive level of user acceptance and system safety. Furthermore, the results point towards a positive correlation between user acceptance and the subjects’ judgment of learning. The Virtual Driving Coach’s concept is a promising approach for efficient and environmentally friendly road transport.

Document type: Article

Grid Mapping for Spatial Pattern Analyses of Recurrent Urban Traffic Congestion Based on Taxi GPS Sensing Data

Scipedia content — Mon, 15 Feb 2021 12:26:55 +0100

Traffic congestion is one of the most serious problems that impact urban transportation efficiency, especially in big cities. Identifying traffic congestion locations and occurring patterns is a prerequisite for urban transportation managers in order to take proper countermeasures for mitigating traffic congestion. In this study, the historical GPS sensing data of about 12,000 taxi floating cars in Beijing were used for pattern analyses of recurrent traffic congestion based on the grid mapping method. Through the use of ArcGIS software, 2D and 3D maps of the road network congestion were generated for traffic congestion pattern visualization. The study results showed that three types of traffic congestion patterns were identified, namely: point type, stemming from insufficient capacities at the nodes of the road network; line type, caused by high traffic demand or bottleneck issues in the road segments; and region type, resulting from multiple high-demand expressways merging and connecting to each other. The study illustrated that the proposed method would be effective for discovering traffic congestion locations and patterns and helpful for decision makers to take corresponding traffic engineering countermeasures in order to relieve the urban traffic congestion issues.

Document type: Article

Secure Plug-in Electric Vehicle (PEV) Charging in a Smart Grid Network

Scipedia content — Mon, 15 Feb 2021 12:23:46 +0100

Charging of plug-in electric vehicles (PEVs) exposes smart grid systems and their users to different kinds of security and privacy attacks. Hence, a secure charging protocol is required for PEV charging. Existing PEV charging protocols are usually based on insufficiently represented and simplified charging models that do not consider the user’s charging modes (charging at a private location, charging as a guest user, roaming within one’s own supplier network or roaming within other suppliers’ networks). However, the requirement for charging protocols depends greatly on the user’s charging mode. Consequently, available solutions do not provide complete protocol specifications. Moreover, existing protocols do not support anonymous user authentication and payment simultaneously. In this paper, we propose a comprehensive end-to-end charging protocol that addresses the security and privacy issues in PEV charging. The proposed protocol uses nested signatures to protect users’ privacy from external suppliers, their own suppliers and third parties. Our approach supports anonymous user authentication, anonymous payment, as well as anonymous message exchange between suppliers within a hierarchical smart grid architecture. We have verified our protocol using the AVISPA software verification tool and the results showed that our protocol is secure and works as desired.

Document type: Article

Modelling vehicular interactions for heterogeneous traffic flow using cellular automata with position preference

Scipedia content — Mon, 15 Feb 2021 12:21:59 +0100

This paper proposes and validates a modified cellular automata model for determining interaction rate (i.e. number of car-following/overtaking instances) using traffic flow data measured in the field. The proposed model considers lateral position preference by each vehicle type and introduces a position preference parameter β in the model which facilitates gradual drifting towards preferred position on road, even if the gap in front is sufficient. Additionally, the model also improves upon the conventional model by calculating safe front and back gap dynamically based on speed and deceleration properties of leader and follower vehicles. Sensitivity analysis was carried out to determine the effect of β on vehicular interactions and the model was calibrated and validated using interaction rates observed in the field. Paired tests were conducted to determine the validity of the model in determining interaction rates. Results of the simulations show that there is a parabolic relationship between area occupancy and interaction rate of different vehicle types. The model performed satisfactorily as the simulated interaction rate between different vehicle types were found to be statistically similar to those observed in field. Also, as expected, the interaction rate between light motor vehicles (LMVs) and heavy motor vehicles (HMVs) were found to be higher than that between LMVs and three wheelers because LMVs and HMVs share the same lane. This could not be done using conventional CA models as lateral movement rules were dictated by only speeds and gaps. So, in conventional models, the vehicles would end up in positions which are not realistic. The position preference parameter introduced in this model motivates vehicles to stay in their preferred positions. This study demonstrates the use of interaction rate as a measure to validate microscopic traffic flow models.

Document type: Article

Analysis of travel pattern and the need to develop sustainable transportation infrastructure in Sarbagita metropolitan area

Scipedia content — Mon, 15 Feb 2021 12:19:13 +0100

Denpasar city is the capital of Bali Province and has been developed into a metropolitan city. There has been an agglomeration of four regencies, namely Denpasar, Badung, Gianyar and Tabanan forming a Metropolitan Sarbagita area with a population close to 2 million inhabitants. With heightened population and activity, travel patterns are increasing and scattered. The development of land use in the Sarbagita Metropolitan area occurred rapidly and was not properly anticipated by the provision of adequate infrastructure. This study aims to examine the patterns of movement that occurs and projections for future conditions as a basis to develop a more sustainable transportation infrastructure. The data used are the origin-destination of people and goods, and statistical population data. The prediction method uses four-stages modeling with the help of Visum software and was validated based on the average daily traffic (ADT) data. The results of the study indicate that traffic accumulation occurs on most arterial and collector roads especially around Denpasar with a degree of saturation exceeding 1. To anticipate future population and increased activities, developing a mass public transport system, multi-mode system, ICT system, and limiting the ownership and use of private motor vehicles is necessary.

Document type: Article

Eco-driving: knowledge and behavior of polish drivers

Scipedia content — Mon, 15 Feb 2021 12:18:56 +0100

In Poland, similarly as in the entire Europe, the quality of air is shaped primarily by communal-living sources and road transport. Due to the steadily increasing share of city residents in the general population, the issue of providing clean air will become a more significant problem for human health over the years, and therefore a stronger incentive to intensify the research. Hence, the key challenge faced by a modern society is to limit the emissions of harmful substances in order to minimize the impact exerted by transport on air pollution and health. Increasingly stringent emission standards are imposed on car manufacturers while on the other hand, the problem of drivers is being ignored namely their awareness of possibilities to reduce the emissions and the ways in which they can help protecting also their own health and life by applying the rules related to the concept of eco-driving in practice. The aim of this paper is to present differences in perception of eco-driving principles in two random and nation-wide surveys: one carried out in 2015 and the other in 2017. Initial conclusions show a major increase (49.4% to 53.2%) of eco-driving awareness among respondents in 2017 when compared to 2015.

Document type: Article

PROBABILISTIC MODEL FOR AIRPORT RUNWAY SAFETY AREAS

Scipedia content — Mon, 15 Feb 2021 12:14:52 +0100

The Laboratory of Aviation Safety and Security at CTU in Prague has recently started a project aimed at runway protection zones. The probability of exceeding by a certain distance from the runway in common incident/accident scenarios (take-off/landing overrun/veer-off, landing undershoot) is being identified relative to the runway for any airport. As a result, the size and position of safety areas around runways are defined for the chosen probability. The basis for probability calculation is a probabilistic model using statistics from more than 1400 real-world cases where jet airplanes have been involved over the last few decades. Other scientific studies have contributed to understanding the issue and supported the model’s application to different conditions.

Document type: Article

Urban road segment level of service based on bicycle users’ perception under mixed traffic conditions

Scipedia content — Mon, 15 Feb 2021 12:06:17 +0100

During the past two decades, several methodologies are endorsed to assess the compatibility of roadways for bicycle use under homogeneous traffic conditions. However, these methodologies cannot be adopted under heterogeneous traffic where on-street bicyclists encounter a complex interaction with various types of vehicles and show divergent operational characteristics. Thus, the present study proposes an initial model suitable for urban road segments in mid-sized cities under such complex situations. For analysis purpose, various operational and physical factors along with user perception data sets (13,624 effective ratings in total) were collected from 74 road segments. Eight important road attributes affecting the bicycle service quality were identified using the most recent and most promising machine learning technique namely, random forest. The identified variables are namely, effective width of outside through lane, pavement condition index, traffic volume, traffic speed, roadside commercial activities, interruptions by unauthorized stoppages of intermittent public transits, vehicular ingress–egress to on-street parking area, and frequency of driveways carrying a high volume of traffic. Service prediction models were developed using ordered probit and ordered logit modeling structures which meet a confidence level of 95%. Prediction performances of developed models were assessed in terms of several statistical parameters and the ordered probit model outperformed the ordered logit model. Incorporating outputs of the probit model, a predictive equation is presented that can identify under what level a segment is offering services for bicycle use. The service levels offered by roadways were classified into six categories varying from ‘excellent’ to ‘worst’ (A–F).

Document type: Article

On the Problem of Constructing Routes, Part II: Methodology and Numerical Example

Scipedia content — Mon, 15 Feb 2021 12:06:03 +0100

"jats:p" We consider a periodic aviation schedule which is a finite collection of flights with given arrival/departure times. For this schedule, we solve the problem of finding the minimal number of aircrafts needed to carry out the flights. The crucial role in solving this problem is played by so-called deficit function (DFs) defined as the difference between departures and arrivals on interval [0,t] for each terminal.

Document type: Article

Differences of Cycling Experiences and Perceptions between E-Bike and Bicycle Users in the United States

Scipedia content — Mon, 15 Feb 2021 11:54:40 +0100

E-bikes are bicycles that provide pedal-assistance to aid people in cycling. Because of the potential of promoting sustainable transportation, more attention has been focused on the e-bike market. This paper investigates the differences of the cycling experience and perceptions between e-bike and conventional bicycle users, using samples drawn from independent bicycle dealer customers. A total of 806 respondents in the United States took the on-line survey, including 363 e-bike-owning respondents. The results show that e-bikes play a more important role in utilitarian travel, such as commuting and running errands, compared to a conventional bicycle. Conventional bicycle-owning respondents use their bicycles more for recreation and exercise. Also, e-bike owners tend to bike longer distances and take more trips per week. Both e-bike respondents and bicycle respondents stated that improved health was a key factor for cycling, while Millennials and Generation X respondents cycle to save time and improve the environment. Finally, an ordered logit model is proposed for evaluating factors that influence interest in future e-bike ownership. Travel purpose, e-bike familiarity, annual household income, and education level are statistically significant factors in the model. These findings begin to provide insight and a profile of potential new markets for e-bikes in the United States.

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Corrosivity Sensor for Exposed Pipelines Based on Wireless Energy Transfer

Scipedia content — Mon, 15 Feb 2021 11:31:46 +0100

External corrosion was identified as one of the main causes of pipeline failures worldwide. A solution that addresses the issue of detecting and quantifying corrosivity of environment for application to existing exposed pipelines has been developed. It consists of a sensing array made of an assembly of thin strips of pipeline steel and a circuit that provides a visual sensor reading to the operator. The proposed sensor is passive and does not require a constant power supply. Circuit design was validated through simulations and lab experiments. Accelerated corrosion experiment was conducted to confirm the feasibility of the proposed corrosivity sensor design.

Document type: Article

PRODUCT ANALYSIS OF BUSINESS AVIATION COMPANIES: A TWO-DIMENSIONAL APPROACH

Scipedia content — Mon, 15 Feb 2021 11:28:01 +0100

Summary. The traditional and current approach to business models in business aviation is based only on aircraft ownership and does not describe the business aviation segment of civil aviation sufficiently. In this paper, we apply a two-dimensional approach analysing the product of companies competing in the business aviation segment of civil aviation. Our analysis combines two product-related components: fleet attributes and portfolio of services to confirm a diversity of business aviation companies and their business models. Using data of thirty business aviation companies from world regions, we reveal a diversity of business models in business aviation that is contradicting with a traditional approach to business models in business aviation.

Document type: Article

Pembelajaran dari Pelayanan Bandar Udara Terhadap Aktivitas General Aviation di"br /"Amerika Serikat"/p"

Scipedia content — Mon, 15 Feb 2021 11:27:30 +0100

Saat ini, kegiatan general aviation memiliki pertumbuhan yang signifikan di dunia penerbangan. Bahkan, kategori bandar udara terbanyak di Amerika Serikat adalah bandar udara general aviation. Penelitian ini bertujuan untuk mendapatkan pemahaman pelayanan bandar udara untuk mendukung aktivitas general aviation berdasarkan pengalaman Amerika Serikat dalam merencanakan skebandarudaraan nasional sehingga dapat memberikan rekomendasi kepada Indonesia dalam mengembangkan bandar udara yang sesuai untuk kegiatan general aviation. Penelitian ini menggunakan strategi kualitatif melalui studi kasus dan metode perbandingan untuk 2 kasus Amerika Serikat dan Indonesia. Data primer dikumpulkan melalui observasi dan wawancara kepada pengelola General Aviation Terminal (GAT) di Bandar Udara Internasional Ngurah Rai dan pengelola Bandar Udara Internasional Halim Perdanakusuma. Data sekunder berasal dari studi dokumentasi. Berdasarkan pengalaman di Amerika Serikat, beberapa rekomendasi antara lain pertimbangan untuk bandar udara general aviation dalam perencanaan kebandarudaraan nasional, pengembangan kriteria bandar udara general aviation, perencanaan fungsi dan aktivitas untuk bandar udara general aviation, dan penyediaan fasilitas di bandar udara general aviation. [Lesson Learned from Airport Services for General Aviation Activities in United States] Nowadays, general aviation activities have significant growth in aviation world. Addition, the highest airport category in United States is general aviation airport. The purpose of this research is to get understanding about airport services to support general aviation activities based on United States; experience in national airport planning to give recommendations for Indonesia in developing airports that compatible with general aviation activities. This research uses qualitative strategy through case study and comparative analysis for two cases the United States and Indonesia. Primary data from was collected through observation and interview with official representative of General Aviation Terminal (GAT) in Ngurah Rai Internasional Airport and manager of Halim Perdanakusuma International Airport. Secondary data came from documentation study. Based on the United States, experience, the recommendations are consideration for general aviation airport on national airport planning, development of basic criteria for general aviation airport, planning of function and activities for general aviation airport, and provision for general aviation airport facilities.

Document type: Article

Neural Network Control System of UAV Altitude Dynamics and Its Comparison with the PID Control System

Scipedia content — Mon, 15 Feb 2021 11:05:56 +0100

This article proposes a comparative method to assess the performance of artificial neural network’s direct inverse control (DIC-ANN) with the PID control system. The comparison served as an analysis tool to assess the advantages of DIC-ANN over conventional control method for a UAV attitude controller. The development of ANN method for UAV control purposes arises due to the limitations of the conventional control method, which is the mathematical based model, involving complex expression, and most of them are difficult to be solved directly into analytic solution. Although the linearization simplified the solving process for such mathematical based model, omitting the nonlinear and the coupling terms is unsuitable for the dynamics of the multirotor vehicle. Thus, the DIC-ANN perform learning mechanism to overcome the limitation of PID tuning. Therefore, the proposed comparative method is developed to obtain conclusive results of DIC-ANN advantages over the linear method in UAV attitude control. Better achievement in the altitude dynamics was attained by the DIC-ANN compared to PID control method.

Document type: Article

Strategy for Research Development in the University. Case Study of Transport and Telecommunication Institute

Scipedia content — Mon, 15 Feb 2021 11:03:26 +0100

"jats:p"The paper represents Transport and Telecommunication Institute research programme for period of time 2016-2020. Developed research programme should insure sustainable development of TTI as research institution and should raise research capabilities of the organization by planning and further implementation of the collaboration activities with national and international partners. The analyses of main technology development in the area of TTI research activities, framework for development of research programme, the structure of key TTI strategies and main directions of TTI research activities are described in the paper sides.

Document type: Article

On Fault Detection and Exclusion in Snapshot and Recursive Positioning Algorithms for Maritime Applications

Scipedia content — Mon, 15 Feb 2021 11:01:45 +0100

Introduction Resilient provision of Position, Navigation and Timing (PNT) data can be considered as a key element of the e-Navigation strategy developed by the International Maritime Organization (IMO). An indication of reliability has been identified as a high level user need with respect to PNT data to be supplied by electronic navigation means. The paper concentrates on the Fault Detection and Exclusion (FDE) component of the Integrity Monitoring (IM) for navigation systems based both on pure GNSS (Global Navigation Satellite Systems) as well as on hybrid GNSS/inertial measurements. Here a PNT-data processing Unit will be responsible for both the integration of data provided by all available on-board sensors as well as for the IM functionality. The IM mechanism can be seen as an instantaneous decision criterion for using or not using the system and, therefore, constitutes a key component within a process of provision of reliable navigational data in future navigation systems. Methods The performance of the FDE functionality is demonstrated for a pure GNSS-based snapshot weighted iterative least-square (WLS) solution, a GNSS-based Extended Kalman Filter (EKF) as well as for a classical error-state tightly-coupled EKF for the hybrid GNSS/inertial system. Pure GNSS approaches are evaluated by combining true measurement data collected in port operation scenario with artificially induced measurement faults, while for the hybrid navigation system the measurement data in an open sea scenario with native GNSS measurement faults have been employed. Results First, the performance of the proposed FDE schemes in terms of the horizontal error is evaluated for both weighted and unweighted approaches in GNSS-based snapshot and KF-based schemes. Here, mainly due to availability of the process model, the KF approaches have demonstrated smaller sensitivity to the injected GNSS faults, while the methods with C N o weighting schemes have resulted in reduced spread of the obtained position solutions. The statistical evaluation of the proposed FDE schemes have been performed for pure GNSS schemes by considering the fault detection rate as a function of the amplitude for the randomly injected GNSS faults. Although the KF-based approaches have clearly outperformed the memoryless schemes, lower detection rates for weighted schemes could be clearly seen due to inability of the FDE to detect faults of fixed amplitude for satellites with lower C N o values. Moreover, the evaluation of the FDE schemes in terms of maximum horizontal position error have indicated bounded response of the FDE schemes when compared to that of non-FDE methods. Finally, the superiority of the FDE-enabled tightly-coupled GNSS/inertial EKF over the non-FDE solution have been demonstrated using a scenario with native GNSS faults. Conclusions The work had successfully demonstrated an applicability of the developed FDE schemes in snapshot and RBE-based algorithms for maritime applications using both non-inertial GNSS-based positioning and a hybrid IMU/GNSS EKF-based approach. The proposed methods form a solid foundation for construction of a more reliable and robust PNT-Unit, where state-of-the-art hybrid navigation algorithms are augmented with integrity monitoring functionality to ensure the system performance in the presence of GNSS faults. The FDE mechanism provides consistent improvements in terms of the horizontal accuracy both in LS and KF-based methods. Although only port operation case and one example of a true GNSS fault in open sea was considered, the presented results are believed to be general enough and the scheme could be adopted for other applications in future.

Document type: Article

Assessment of Possibilities to Use Thermal Imaging Cameras for Air Traffic Control

Scipedia content — Mon, 15 Feb 2021 11:01:14 +0100

"jats:p"The character of missions and conditions in which they are carried out by military un-manned aerial vehicles are usually special and difficult. This causes a necessity to provide support for their missions, especially with regard to checking their condition on the controlled or autonomic flight path, especially during landing and take-off operations."/jats:p" "jats:p"This paper offers an account of an experiment and an attempt of assessing usefulness of thermal imaging cameras for controlling flights of aerial vehicles, mainly in areas of air-dromes and approach paths.

Document type: Article

Heterogeneous Data Fusion Method to Estimate Travel Time Distributions in Congested Road Networks

Scipedia content — Mon, 15 Feb 2021 10:58:45 +0100

Travel times in congested urban road networks are highly stochastic. Provision of travel time distribution information, including both mean and variance, can be very useful for travelers to make reliable path choice decisions to ensure higher probability of on-time arrival. To this end, a heterogeneous data fusion method is proposed to estimate travel time distributions by fusing heterogeneous data from point and interval detectors. In the proposed method, link travel time distributions are first estimated from point detector observations. The travel time distributions of links without point detectors are imputed based on their spatial correlations with links that have point detectors. The estimated link travel time distributions are then fused with path travel time distributions obtained from the interval detectors using Dempster-Shafer evidence theory. Based on fused path travel time distribution, an optimization technique is further introduced to update link travel time distributions and their spatial correlations. A case study was performed using real-world data from Hong Kong and showed that the proposed method obtained accurate and robust estimations of link and path travel time distributions in congested road networks.

Document type: Article

Measuring Crowdedness between Adjacent Stations in an Urban Metro System: a Chinese Case Study

Scipedia content — Mon, 15 Feb 2021 10:57:42 +0100

The urban metro system has been widely appreciated as the most important component in urban infrastructures. It plays a critical role in promoting urban social and economic development, and particularly in reducing the urban traffic congestion. However, there are various inherent problems with operating metro systems, which typically involve the crowdedness both at stations and inside vehicles. Both policymakers and academic researchers in China have paid little attention to the crowdedness between metro stations. In order to solve the problem of crowdedness, it is necessary to develop a method to evaluate the level of crowdedness. This work establishes a model to measure the crowdedness between adjacent stations in a metro system based on the load factor principle, passenger standing density, and other factors such as the metro operation schedule and estimations of passenger flows. The Chongqing Metro Line 3 in China is used as a case study to demonstrate the application of the evaluation model. The case study reveals that the model introduced in this study can assist with assessing the crowdedness level between adjacent stations in a metro line. The model is an effective tool for helping the metro management and administration understand the level of crowdedness, apply proper methods to mitigate the crowdedness, and thus improve the quality of the service for those utilizing the metro system.

Document type: Article

Modeling Lane-Changing Behavior in Freeway Off-Ramp Areas from the Shanghai Naturalistic Driving Study

Scipedia content — Mon, 15 Feb 2021 10:56:06 +0100

The objective of this study is to investigate lane-changing characteristics in freeway off-ramp areas using Shanghai Naturalistic Driving Study (SH-NDS) data, considering a four-lane freeway stretch in various traffic conditions. In SH-NDS, the behavior of drivers is observed unobtrusively in a natural setting for a long period of time. We identified 433 lane-changing events with valid time series data from the whole dataset. Based on the logit model developed to analyze the choice of target lanes, a likelihood analysis of lane-changing behavior was graphed with respect to three traffic conditions: free flow, medium flow, and heavy flow. The results suggested that lane-changing behavior of exiting vehicles is the consequence of the balance between route plan (mandatory incentive) and expectation to improve driving condition (discretionary incentive). In higher traffic density, the latter seems to play a significant role. Furthermore, we found that lane-change from the slow lane to the fast lane would lead to higher speed variance value, which indicates a higher crash risk. The findings contribute to a better understanding on drivers’ natural driving behavior in freeway off-ramp areas and can provide important insight into road network design and safety management strategies.

Document type: Article

A Model for Assessing Pedestrian Corridors. Application to Vitoria-Gasteiz City (Spain)

Scipedia content — Mon, 15 Feb 2021 10:45:35 +0100

From a mobility perspective, walking is considered to be the most sustainable transport mode. One of the consequences of motor-oriented urban configuration on pedestrian mobility is urban fragmentation, which affects sustainability in cities. In this paper, we use a natural-based approach to landscape fragmentation and connectivity (inherited from landscape ecology) for pedestrian mobility planning. Our aim is to design a useful methodology to identify priority pedestrian corridors, and to assess the effects of implementing barrier-free pedestrian corridors in the city. For this purpose, we developed a method that integrates Geographical Information Systems (GIS) network analysis with kernel density methods, which are commonly used for designating habitat corridors. It was applied to Vitoria-Gasteiz (Spain). Pedestrian mobility was assessed by comparison of travel times between different scenarios. Results show that the implementation of pedestrian corridors reduces travel time by approximately 6%. Thus, an intervention in a small percentage of the city’s street network could considerably reduce pedestrian travel times. The proposed methodology is a useful tool for urban and transport planners to improve pedestrian mobility and manage motorised traffic.

Document type: Article

Rail fatigue crack propagation in high-speed wheel/rail rolling contact

Scipedia content — Mon, 15 Feb 2021 10:41:39 +0100

To study the wheel/rail rolling contact fatigue of high-speed trains, we obtain the distribution of contact forces between wheel and rail by introducing the strain-rate effect. Based on the finite element simulation, a two-dimensional finite element model is established, and the process of a wheel rolling over a crack is analyzed to predict the crack propagation direction. The statistics of possible crack propagation angles are calculated by the maximum circumferential stress criterion. The crack path is then obtained by using the average crack propagation angle as the crack propagation direction according to Weibull distribution. Results show that the rail crack mode of low-speed trains is different from that of high-speed trains. The rail crack propagation experiences a migration from opening mode to sliding mode under the low-speed trains; however, the rail crack mainly propagates in the opening mode under high-speed trains. Furthermore, the crack propagation rate for high-speed trains is faster than that for low-speed trains. The simulated crack paths are consistent with the experimental ones, which proves that it is reasonable to use the average value of possible crack propagation directions as the actual crack propagation direction.

Document type: Article

CHARGING RAILWAY INFRASTRUCTURE MODELS AND THEIR IMPACT TO COMPETITIVENESS OF RAILWAY TRANSPORT

Scipedia content — Mon, 15 Feb 2021 10:38:21 +0100

Summary. The paper deals with the impact the charging railway infrastructure access has on the competitiveness of railway transport in the selected European countries. It researched into the development of indicators that indicate the competition in the railways transport market, such as volume of transport, traffic performances, and number of trains of private railway operators compared with national operators. It used the new approach for research of the share of railway transport in the transport market. The research was based on a comparative analysis of models of charging railway infrastructure, subsidies to rail infrastructure, and development of transport performances of all rail operators. The results of research are presented in terms of freight and passenger railway transport.

Document type: Article

Schoolbus driver performance can be improved with driver training, safety incentivisation, and vehicle roadworthy modifications

Scipedia content — Mon, 15 Feb 2021 10:35:45 +0100

In South Africa (SA), the school transport industry provides millions of children with a means of travelling to and from school. The industry has, however, been reported to be plagued by widespread safety concerns. The consequent road traffic incidents have often been attributed to driver factors, including driving in excess of legal speeds or at inappropriate speeds; driving while under the influence of alcohol, while sleepy or fatigued; or driving without using protective equipment for vehicle occupants. There are currently very few SA interventions that specifically target this important industry role-player. The Safe Travel to School Programme was recently implemented by a national child safety agency, with a focus on driver road safety awareness, defensive driver training, eye- testing, vehicle roadworthy inspections with selected upgrades, incentives for safe performance, and implementation of a vehicle telematics tracking system with regular, individual driving behaviour information updates. This quasi-experimental study offers an evaluation of the initial impact on safety performance of this telematics-based driver and vehicle safety intervention in terms of speeding, acceleration, braking, cornering, and time-of-day driving, and compares the school transport driver performance with that of general motorists. Despite concerns that some school transport vehicles are used for multiple purposes outside of school transport duties, at night, and for longer distances, overall these vehicles recorded lower percentages of speeding, lower harsh braking, and lower average harsh cornering and acceleration than general drivers.

Document type: Article

Assessment of Common and Emerging Bioinformatics Pipelines for Targeted Metagenomics

Scipedia content — Mon, 15 Feb 2021 10:34:34 +0100

International audience; Targeted metagenomics, also known as metagenetics, is a high-throughput sequencing application focusing on a nucleotide target in a microbiome to describe its taxonomic content. A wide range of bioinformatics pipelines are available to analyze sequencing outputs, and the choice of an appropriate tool is crucial and not trivial. No standard evaluation method exists for estimating the accuracy of a pipeline for targeted metagenomics analyses. This article proposes an evaluation protocol containing real and simulated targeted metage-nomics datasets, and adequate metrics allowing us to study the impact of different variables on the biological interpretation of results. This protocol was used to compare six different bioinformatics pipelines in the basic user context: Three common ones (mothur, QIIME and BMP) based on a clustering-first approach and three emerging ones (Kraken, CLARK and One Codex) using an assignment-first approach. This study surprisingly reveals that the effect of sequencing errors has a bigger impact on the results that choosing different amplified regions. Moreover, increasing sequencing throughput increases richness overestima-tion, even more so for microbiota of high complexity. Finally, the choice of the reference database has a bigger impact on richness estimation for clustering-first pipelines, and on correct taxa identification for assignment-first pipelines. Using emerging assignment-first pipelines is a valid approach for targeted metagenomics analyses, with a quality of results comparable to popular clustering-first pipelines, even with an error-prone sequencing technology like Ion Torrent. However, those pipelines are highly sensitive to the quality of databases and their annotations, which makes clustering-first pipelines still the only reliable approach for studying microbiomes that are not well described.

Document type: Article

Locating Station of One-Way Carsharing Based on Spatial Demand Characteristics

Scipedia content — Mon, 15 Feb 2021 10:33:57 +0100

This study aims to explore factors that affect carsharing demand characteristics in different time periods based on EVCARD transaction data, which is the largest station-based one-way carsharing program in Shanghai, China. Monthly usage intensity and degree of usage imbalance are used as proxies of demand. This study uses three groups of independent variables: carsharing station attributes, built environment (density, diversity, design, and destination accessibility), and transportation facilities. The adaptive elastic net regression is developed to identify factors that influence carsharing usage intensity and degree of usage imbalance after factor selection using extra-randomized-tree algorithm. Finally, a station layout is proposed according to both usage intensity and degree of imbalance. The main results of this study are presented as follows: "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"""mml:mo stretchy="false""("/mml:mo""mml:mn fontstyle="italic""1"/mml:mn""mml:mo stretchy="false"")"/mml:mo""/mml:math" different effects of built environment and transportation factors cause dynamic demand across different time periods; "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"""mml:mo stretchy="false""("/mml:mo""mml:mn fontstyle="italic""2"/mml:mn""mml:mo stretchy="false"")"/mml:mo""/mml:math" factors with positive and negative effect on carsharing demand are divided clearly for guidance of the carsharing station layout; "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"""mml:mo stretchy="false""("/mml:mo""mml:mn fontstyle="italic""3"/mml:mn""mml:mo stretchy="false"")"/mml:mo""/mml:math" public parking space leads to more personal vehicle trip compared to a carsharing trip; and "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"""mml:mo stretchy="false""("/mml:mo""mml:mn fontstyle="italic""4"/mml:mn""mml:mo stretchy="false"")"/mml:mo""/mml:math" as public transportation, the relationship of the metro and carsharing is complementary. However, the bus stop and carsharing have a competitive relationship. This study provides a carsharing layout method based on both usage intensity and degree of imbalance. Furthermore, several policies concerning carsharing are proposed.

Document type: Article

Improvement of Network Performance by In-Vehicle Routing Using Floating Car Data

Scipedia content — Mon, 15 Feb 2021 10:31:46 +0100

This paper describes a study which gives insight into the size of improvement that is possible with individual in-car routing advice based on the actual traffic situation derived from floating car data (FCD). It also gives an idea about the required penetration rate of floating car data needed to achieve a certain degree of improvement. The study uses real loop detector data from the region of Amsterdam collected for over a year, a route generating algorithm for in-car routing advice, and emulated floating car data to generate the routing advice. The case with in-car routing advice has been compared to the base case, where drivers base their routing decisions on average knowledge of travel times in the network. The improvement in total delay using the in-vehicle system is dependent on penetration rate and accuracy of the floating car data and varies from 2.0% to 3.4% for 10% penetration rate. This leads to yearly savings of about 15 million euros if delay is monetarised using standard prices for value of time (VOT). © 2017 Gerdien A. Klunder et al.

Document type: Article

Restrained mobility in a high-accessible and migrant-rich area in downtown Beijing

Scipedia content — Mon, 15 Feb 2021 10:31:29 +0100

Purpose Immigrant travel has become an emerging research field in transportation planning. A handful of scholars have studied the travel behavior of residents in immigrant enclaves in North America. However, thus far, there has been no analysis of the travel behavior of residents living in migrant-rich neighborhoods in China. Additionally, previous studies rarely explored whether these (im)migrants could benefit from resources outside the neighborhoods, and the determinants of their travel to destinations outside the neighborhoods. This study aims to fill these research gaps in the literature. We used a migrant-rich area in downtown Beijing as a case study to understand the daily mobility and the determinants, and strategies to enhance mobility of neighborhood residents. Method To answer the above questions, in-depth interview in Dashilar was used in this study. Eighteen migrant workers were recruited by using snowball sampling, and six local residents were recruited as “observers” to view the mobility of migrant workers from another perspective. The interviews were digitally recorded, transcribed and coded. Results The research results show that the interviewees had restrained mobility, limited to the area within Dashilar. Their work location was near residence, and they seldom made recreation and social trips. One of the major reasons for this was that their social ties were highly restricted to people from the same hometown. Additionally, time and financial poverty further limited their mobility. Institutional barriers also segregated migrant workers with local people in job market, urban welfare and daily life. In order to improve physical mobility, migrant workers used electric bicycle as their daily travel facility. The use of mobile phone also improved their virtual mobility by facilitating information flow and extending social networks. Moreover, community initiatives such as community activities and volunteers helped to improve their mobility. Conclusions Dashilar is an area with abundant transport resources and activity destination choices, but migrant workers living there still restrained their daily travel within the neighborhood. Although resources within the neighborhood facilitated daily necessities of migrant workers living in Dashilar, they seldom benefited from the resources outside the neighborhood, which played a larger role in promoting their social and cultural assimilation in the city. Their limited local social ties, individual time and money constraints, and institutional factors all contributed to their limited destination motivations and aspirations. To cope with these challenges, migrant workers and communities both adopted several strategies. These strategies could address the above challenges to some extent, but their limitations also fixed mobility of migrant workers. Combination of Internet of mobile phone and community initiatives was a feasible way to link migrant workers and local people, and help them to improve enlarge mobility space.

Document type: Article

A Model for the Evaluation of Brazilian Road Transport: A Sustainable Perspective

Scipedia content — Mon, 15 Feb 2021 10:30:01 +0100

Freight transportation in Brazil is heavily based on the road mode bringing heavy dependence of this mode to the country and some consequences such as high operating costs and high air emissions. For these reasons, it was considered the necessity of evaluating new investments made in this mode from a sustainable perspective, taking into account not only economic but also social and environmental concepts. Towards this purpose, the study develops an evaluation model of road transport infrastructure, the TIM, which will help decision making in situations of choice between different alternatives of road projects. The model includes ten variables that count from the initial investment in the road to air emissions of carbon dioxide. All are monetarized individually and then consolidated into a single equation. The result of applying the model is innovative when considering the three spheres of sustainability to evaluate future road transport projects and rank them.

Document type: Article

Traffic Peak Period Detection from an Image Processing View

Scipedia content — Mon, 15 Feb 2021 10:29:33 +0100

Traffic peak period detection is very important for the guidance and control of traffic flow. Most common methods for traffic peak period detection are based on data analysis. They have achieved good performance. However, the detection processes are not intuitional enough. Besides that, the accuracy of these methods needs to be improved further. From an image processing view, we introduce a concept in corner detection, sharpness, to detect the traffic peak periods in this paper. The proposed method takes the traffic peak period detection problem as a salient point detection problem and uses the image processing strategies to solve this problem. Firstly, it generates a speed curve image with the speed data. With this image, the method for detection of salient points is adopted to obtain the peak point candidates. If one candidate has the lowest speed value, this candidate is the peak point. Finally, the peak period is gotten by moving forward and backward the corresponding time of the peak point with a time interval. Experimental results show that the proposed method has achieved higher accuracy. More importantly, as the proposed method solves the traffic peak period detection problem from an image processing view, it has more intuition.

Document type: Article

Scoping assessment of building vibration induced by railway traffic

Scipedia content — Mon, 15 Feb 2021 10:29:17 +0100

This work presents a scoping model to predict ground-borne railway vibration levels within buildings considering soil-structure interaction (SSI). It can predict the response of arbitrarily complex buildings in a fraction of the time typically required to analyse a complex SSI problem, and thus provides a practical tool to rapidly analyse the vibration response of numerous structures near railway lines. The tool is designed for use in cases where the ground-borne vibration is known, and thus can be used as model input. Therefore in practice, for the case of a new line, the ground motion can be computed numerically, or alternatively, for the case of new buildings to be constructed near an existing line, it can be recorded directly (e.g. using accelerometers) and used as model input. To achieve these large reductions in computational time, the model discretises the ground-borne vibration in the free field into a frequency range corresponding to the modes that characterize the dynamic building response. After the ground-borne response spectra that corresponds with the incident wave field is estimated, structural vibration levels are computed using modal superposition, thus avoiding intensive soil-structure interaction computations. The model is validated using a SSI problem and by comparing results against a more complex finite element-boundary element model. Finally, the new scoping model is then used to analyse the effect of soil properties, building height, train speed and distance between the building and the track on structural-borne vibration. The results show that the scoping model provides a powerful tool for use during the early design stages of a railway system when a large number of structures require analysis. Ministerio de Economía y Competitividad (España) BIA2013-43085-P

Document type: Article

Analysis of Socio-spatial Differentiation in Transport Mode Choice Preferences

Scipedia content — Mon, 15 Feb 2021 10:21:28 +0100

Starting from the fact that the transport mode choice is one of those aspects of travel behaviour that, to a great extent, affects the efficiency of the transport system, this paper analyses the factors that contribute to the use of public and car transport. The goals of the analysis were to obtain insight into the preferences for using these two modes of transport in Croatia and find out to which extent the basic demographic and socioeconomic characteristics of the respondents affect the usage of car and public transport and the possibility of taking trips by these transport modes. The paper analyses the data collected by surveys on a representative national sample. The results show that in Croatia, the number of people who frequently use public transport is far fewer than the number of frequent users of passenger car transport. However, the comparison has found that the number of frequent public transport users varies significantly among certain categories of respondents. Using binary logistic regression analysis has determined that the preferences towards the frequent use of car or public transport are significantly influenced by the age of the respondents, size of the settlement, accessibility of the destinations by public transport, the number of vehicles in the household and whether the respondent is the main car user in the household.

Document type: Article

Minimization of Load Variance in Power Grid – Investigation on Vehicle-to-Grid Optimal Scheduling

Scipedia content — Mon, 15 Feb 2021 10:20:00 +0100

The introduction of electric vehicles into the transportation sector helps reduce global warming and carbon emissions. The interaction between electric vehicles and the power grid has spurred the emergence of a smart grid technology, denoted as vehicle-to grid-technology. Vehicle-to-grid technology manages the energy exchange between a large fleet of electric vehicles and the power grid to accomplish shared advantages for the vehicle owners and the power utility. This paper presents an optimal scheduling of vehicle-to-grid using the genetic algorithm to minimize the power grid load variance. This is achieved by allowing electric vehicles charging (grid-to-vehicle) whenever the actual power grid loading is lower than the target loading, while conducting electric vehicle discharging (vehicle-to-grid) whenever the actual power grid loading is higher than the target loading. The vehicle-to-grid optimization algorithm is implemented and tested in MATLAB software (R2013a, MathWorks, Natick, MA, USA). The performance of the optimization algorithm depends heavily on the setting of the target load, power grid load and capability of the grid-connected electric vehicles. Hence, the performance of the proposed algorithm under various target load and electric vehicles’ state of charge selections were analysed. The effectiveness of the vehicle-to-grid scheduling to implement the appropriate peak load shaving and load levelling services for the grid load variance minimization is verified under various simulation investigations. This research proposal also recommends an appropriate setting for the power utility in terms of the selection of the target load based on the electric vehicle historical data. Minimization of Load Variance in Power Grid – Investigation on Vehicle-to-Grid Optimal Scheduling

Document type: Article

Cars and ground-level ozone: how do fuels compare?

Scipedia content — Mon, 15 Feb 2021 10:17:54 +0100

Introduction An important question for policy-makers is how the main automotive fuels – diesel, gasoline, LPG (and increasingly, electricity) – compare in terms of ground-level ozone formation. Methods Based on recent, equivalent emissions data, the study compares ozone formation on a per-kilometre basis of the main fuels: gasoline, diesel, liquefied petroleum gas and electricity (the latter in the United Kingdom). Results Considering tailpipe emissions only, gasoline’s and LPG’s per-kilometre ozone impact is 44–88% of diesel’s, while LPG’s is slightly lower than gasoline’s. If fuel production and tailpipe emissions are added together, the liquid fuels generate 48–80% of electricity’s impact, i.e. the electric car’s ozone impact is highest. The liquids’ ozone-impact rankings are the same as for tailpipe only, from most to least: diesel, gasoline, LPG. Conclusions Changing the fuel/energy type of a passenger car changes its emission inventory, so this could be a useful policy in combating ozone, i.e. governments could encourage some fuels/energies and discourage others. Based on the results shown above, a priority ranking of the main types, from best to worst in the United Kingdom, is: LPG, gasoline, diesel and battery electric. For electric, this ranking will vary in other regions, depending on the emissions of the power-generation grid. For the liquid fuels, the rankings are valid for Europe and North America in general. Impact assessment of ozone is complex, because the chemistry of its formation is complex. This complexity is only partially incorporated in existing impact assessment methods.

Document type: Article

Ship Power System Analysis Based on Safety Aspects

Scipedia content — Mon, 15 Feb 2021 10:15:59 +0100

"jats:p"This article analyses the reasons for the reduction of insulating resistance, processes influencing them and isolation diagnostic methods. It provides a short description of electrical safety situation on ships with isolated neutral electrical power systems. It also covers the methods of protecting personnel from electric shock or preventing ignition or arching damage at the fault location with the help of fault current compensation. Principal fault current compensation circuit diagrams are analysed by using the minimum value and time of transient fault current as criteria.

Document type: Article

An evaluation of train control information systems for sustainable railway using the analytic hierarchy process (AHP) model

Scipedia content — Mon, 15 Feb 2021 10:10:30 +0100

Purpose In the process of nowadays efficiency evaluation of any mode of transportation, sustainability results are the most important factor. In regard to railway sustainability, Train Control Information Systems (TCIS) are such advanced systems with important positive impacts. The main purpose of this study was therefore the evaluation of these impacts as well as the evaluation of Key Performance Themes (KPT) for sustainable railways. Methods Firstly a very detailed literature review of papers that have focused on TCIS and their improvements on railway sustainability, published in the scientific journal in the period from 2005 and 2016, was performed. The number of studies was then used as a main criteria in Analytical Hierarchical Process (AHP) evaluations or rankings of these systems and their impacts. Results The paper offers results from the first systematic review of papers which investigate the role of TCIS in terms of sustainability and, additionally, represents a refined approach to TCIS classification with a new classes descriptions. During review KPT for sustainable railways were also identified. Further, AHP evaluated the Train Management and Interlocking Systems and their subsystems as the most important TCIS, and safety and costs of equipment, installation, maintenance and operation as the most important themes. Conclusions The results are important for both, scholars for their future research and for other railway stakeholders and decision makers, who must select different systems and technologies for implementation in their railway systems with emphasis on increasing performance and sustainability. The study offers also the opportunities for further research in regard to railway sustainability.

Document type: Article

Transient heat transfer at fluid flow in a thick-walled pipeline

Scipedia content — Mon, 15 Feb 2021 10:05:31 +0100

The work aims to determine the transient temperature distribution of the medium and the pipeline wall using the finite difference method. Time courses of the temperature of the flowing medium and pipeline walls caused by a step change in temperature of the medium at the pipeline inlet, obtained by the numerical method, were compared with the courses calculated using strict analytical formulas. The numerical method of determining the transient distribution of temperature of medium and pipeline wall can be used in the analysis of heating and cooling of heating or steam pipelines with any changes in time of mass flow rate of the flowing medium or temperature of the medium at the inlet to the pipeline.

Document type: Article

Particle Flow Characteristics and Transportation Optimization of Superfine Unclassified Backfilling

Scipedia content — Mon, 15 Feb 2021 10:04:56 +0100

In order to investigate the high volume fraction problem of the solid phase in superfine unclassified backfilling pipeline transportation, characteristic parameters were obtained by fitting to test data with an R–R particle size distribution function; then, a Euler dense-phase DPM (Discrete phase model) model was established by applying solid–liquid two-phase flow theory and the kinetic theory of granular flow (KTGF). The collision and friction of particles were imported by the UDF (User-define function) function, and the pipeline fluidization system, dominated by interphase drag forces, was analyzed. The best concentration and flow rate were finally obtained by comparing the results of the stress conditions, flow field characteristics, and the discrete phase distributions. It is revealed that reducing the concentration and flow rate could control pressure loss and pipe damage to a certain degree, while lower parameters show negative effects on the transportation integrity and backfilling strength. Indoor tests and field industrial tests verify the reliability of the results of the numerical simulations. Research shows that the model optimization method is versatile and practical for other, similar, complex flow field working conditions.

Document type: Article

Urban traffic estimations for bus passengers in Bahía Blanca city, Argentina. 2007-2014

Scipedia content — Mon, 15 Feb 2021 10:03:14 +0100

Resumen: En este artículo se realiza una estimación de los determinantes de la demanda de transporte urbano de pasajeros por colectivo de la ciudad de Bahía Blanca, para tal fin se recabaron datos mensuales del periodo 2007-2014. Se utilizan técnicas de panel de datos con efectos fijos, que admiten heterogeneidad entre líneas y mejoran la precisión de las estimaciones. La estimación permite obtener elasticidades respecto de la tarifa, del costo de desplazarse en medios alternativos y analizar el rol del nivel general de precios en el volumen de pasajeros que viajan en colectivo. Abstract: This article aims to estimate the determinants of the demand for urban passenger transport by bus in the city of Bahia Blanca using monthly data for the 2007-2014 period. Fixed effects panel data techniques which support heterogeneity between lines are used and thus increase precision of estimates. Estimations produce elasticities (e.g. fare, cost of travel in alternative modes) which allows us to analyze the role of the general price level in the demand of bus transport.

Document type: Article

Strategic Allocation of Flight Plans in Air Traffic Management: An Evolutionary Point of View

Scipedia content — Mon, 15 Feb 2021 10:01:06 +0100

We present a simplified model of the strategic allocation of trajectories in a generic airspace for commercial flights. In this model, two types of companies, characterised by different cost functions and different strategies, compete for the allocation of trajectories in the airspace. With an analytical model and numerical simulations, we show that the relative advantage of the two populations -- companies -- depends on external factors like traffic demand as well as on the composition of the population. We show that there exists a stable equilibrium state which depends on the traffic demand. We also show that the equilibrium solution is not the optimal at the global level, but rather that it tends to favour one of the two business models -- the archetype for low-cost companies. Finally, linking the cost of allocated flights with the fitness of a company, we study the evolutionary dynamics of the system, investigating the fluctuations of population composition around the equilibrium and the speed of convergence towards it. We prove that in the presence of noise due to finite populations, the equilibrium point is shifted and is reached more slowly.

Document type: Article

Leader-Follower Based Locally Rigid Formation Control

Scipedia content — Mon, 15 Feb 2021 10:00:21 +0100

This paper addresses motion control of a cooperative intelligent transport system (C-ITS) of nonholonomic mobile robots navigating a dynamic environment while maintaining a locally rigid formation. We consider the design of acceleration-based control inputs that govern the motion of cooperative intelligent transport system (C-ITS) using the artificial potential fields method for the avoidance of obstacles and attraction to designated targets. The control scheme utilizes a new leader-follower strategy using Cartesian coordinates to accomplish a collision-free locally rigid formation of an autonomous and intelligent transportation system. The concepts of virtual parking bays and"jats:italic" minimum distance technique"/jats:italic" (MDT) are utilized to attain prescribed orientations of the formation at the final destination. The robustness of the control scheme is established by considering the effect noise on the formation, while the effectiveness of the proposed nonlinear control laws is demonstrated through computer simulations.

Document type: Article

Importance of Personal Data Protection Law for Commercial Air Transport

Scipedia content — Mon, 15 Feb 2021 09:59:17 +0100

"jats:p"In the review below the author presents a general overview of the selected contemporary legal issues related to the present growth of the aviation industry and the development of aviation technologies. The review is focused on the questions at the intersection of aviation law and personal data protection law. Massive processing of passenger data (Passenger Name Record, PNR) in IT systems is a daily activity for the contemporary aviation industry. Simultaneously, since the mid- 1990s we can observe the rapid growth of personal data protection law as a very new branch of the law. The importance of this new branch of the law for the aviation industry is however still questionable and unclear. This article includes the summary of the author’s own research conducted between 2011 and 2017, in particular his audits in LOT Polish Airlines (June 2011-April 2013) and Lublin Airport (July - September 2013) and the author’s analyses of public information shared by International Civil Aviation Organization (ICAO), International Air Transport Association (IATA), Association of European Airlines (AEA), Civil Aviation Authority (ULC) and (GIODO). The purpose of the author’s research was to determine the applicability of the implementation of technical and organizational measures established by personal data protection law in aviation industry entities.

Document type: Article

Benefits on public health from transport-related greenhouse gas mitigation policies in Southeastern European cities

Scipedia content — Mon, 15 Feb 2021 09:57:43 +0100

Climate change is a major environmental threat of our time. Cities have a significant impact on greenhouse gas emissions as most of the traffic, industry, commerce and more than 50% of world population is situated in urban areas. Southern Europe is a region that faces financial turmoil, enhanced migratory fluxes and climate change pressure. The case study of Thessaloniki is presented, one of the only two cities in Greece with established climate change action plans. The effects of feasible traffic policies in year 2020 are assessed and their potential health impact is compared to a business as usual scenario. Two types of measures are investigated: operation of underground rail in the city centre and changes in fleet composition. Potential co-benefits from reduced greenhouse gas emissions on public health by the year 2020 are computed utilizing state-of-the-art concentration response functions for PM x , NO 2 and C 6 H 6 . Results show significant environmental health and monetary co-benefits when the city metro is coupled with appropriate changes in the traffic composition. Monetary savings due to avoided mortality or leukaemia incidence corresponding to the reduction in PM 10 , PM 2.5, NO 2 and C 6 H 6 exposure will be 56.6, 45, 37.7 and 1.0 million Euros respectively. Promotion of ‘green’ transportation in the city (i.e. the wide use of electric vehicles), will provide monetary savings from the reduction in PM 10 , PM 2.5 , NO 2 and C 6 H 6 exposure up to 60.4, 49.1, 41.2 and 1.08 million Euros. Overall, it was shown that the respective GHG emission reduction policies resulted in clear co-benefits in terms of air quality improvement, public health protection and monetary loss mitigation.

Document type: Article

Path creation in Nordic energy and road transport systems:The role of technological characteristics

Scipedia content — Mon, 15 Feb 2021 09:56:44 +0100

This paper reviews path-creation processes in road transport systems in the Nordic countries: e-mobility in Denmark, hydrogen and fuel-cell electrical vehicles in Norway, and advanced biofuels in Finland and Sweden. The study builds on the path creation literature, which seeks to explain the emergence of new technological pathways. Drawing on recent insights concerning the differences between design- and manufacturing-intensive technologies, the paper analyses the influence of technological characteristics on path creation processes. The case comparison indicates that technological characteristics seem to have greater influence on the content of activities in the later phase rather than the early phase of path creation processes. The analysis also emphasises that barriers to path creation processes differ depending on technological characteristics. This highlights the importance of considering technological characteristics in energy and transport policies.

Document type: Article

Habilidades auditivas de figura-fundo e fechamento em controladores de tráfego aéreo

Scipedia content — Mon, 15 Feb 2021 09:56:13 +0100

RESUMO Objetivo Investigar o perfil das habilidades auditivas de fechamento e figura-fundo e fatores relacionados à atenção, comunicação e saúde de controladores de tráfego aéreo (CTA) de aproximação de aeronaves e comparar com os de outros profissionais civis e militares. Método Participaram 60 adultos com limiares audiométricos normais reunidos em dois grupos, pareados por idade e gênero: o grupo estudo formado por 30 profissionais do Controle de Aproximação de aeronaves e o controle, por 30 outros servidores civis e militares. Todos foram submetidos a perguntas relacionadas à atenção, comunicação e saúde e ao Teste de Fala com Ruído e de Identificação de Sentenças Sintéticas em escuta monótica (SSI) para avaliar fechamento e figura-fundo, respectivamente. Foram usados testes estatísticos não paramétricos e análise de regressão logística. Resultados O CTA autorreferiu maior cansaço/esgotamento e estresse e obteve melhor desempenho do que o grupo controle em figura-fundo e semelhante em fechamento. Foi observado que ocorreu uma probabilidade de ser CTA para o estresse em 5,59 vezes e para identificação de sentenças em escuta monótica à orelha direita de 1,24. Conclusão Fechamento e autorrelato de dificuldades de saúde, comunicação e atenção na maioria das questões foram similares em ambos os grupos. Figura-fundo foi significativamente melhor em CTA. Autorreferência de estresse e desempenho à orelha direita no SSI foram preditores significantes do indivíduo ser do CTA. ABSTRACT Purpose To investigate the auditory skills of closure and figure-ground and factors associated with health, communication, and attention in air traffic controllers, and compare these variables with those of other civil and military servants. Methods Study participants were sixty adults with normal audiometric thresholds divided into two groups matched for age and gender: study group (SG), comprising 30 air traffic controllers and control group (CG), composed of 30 other military and civil servants. All participants were asked a number of questions regarding their health, communication, and attention, and underwent the Speech-in-Noise Test (SIN) to assess their closure skills and the Synthetic Sentence Identification Test - Ipsilateral Competitive Message (SSI-ICM) in monotic listening to evaluate their figure-ground abilities. Data were compared using nonparametric statistical tests and logistic regression analysis. Results More individuals in the SG reported fatigue and/or burnout and work-related stress and showed better performance than that of individuals in the CG for the figure-ground ability. Both groups performed similarly and satisfactorily in the other hearing tests. The odds ratio for participants belonging in the SG was 5.59 and 1.24 times regarding work-related stress and SSI-ICM (right ear), respectively. Conclusion Results for the variables auditory closure, self-reported health, attention, and communication were similar in both groups. The SG presented significantly better performance in auditory figure-ground compared with that of the CG. Self-reported stress and right-ear SSI-ICM were significant predictors of individuals belonging to the SG.

Document type: Article

Application of Data Clustering to Railway Delay Pattern Recognition

Scipedia content — Mon, 15 Feb 2021 09:53:45 +0100

italic"K"/jats:italic"-means clustering is employed to identify recurrent delay patterns on a high traffic railway line north of Copenhagen, Denmark. The clusters identify behavioral patterns in the very large (“big data”) datasets generated automatically and continuously by the railway signal system. The results reveal the conditions where corrective actions are necessary, showing the cases where recurrent delay patterns take place. Delay profiles and delay change profiles are generated from timestamps to compare different train runs and to partition the set of observations into groups of similar elements."jats:italic" K"/jats:italic"-means clustering can identify and discriminate different patterns affecting the same stations, which is otherwise difficult in previous approaches based on visual inspection. Classical methods of univariate analysis do not reveal these patterns. The demonstrated methodology is scalable and can be applied to any system of transport.

Document type: Article

Data stories from urban loading bays

Scipedia content — Mon, 15 Feb 2021 09:49:14 +0100

Purpose Freight vehicle parking facilities at large urban freight traffic generators, such as urban retail malls, are often characterized by a high volume of vehicle arrivals and a poor parking supply infrastructure. Recurrent congestion of freight parking facilities generates environmental (e.g. pollution), economic (e.g. delays in deliveries) and social (e.g. traffic) negative externalities. Solutions aimed at either improving or better managing the existing parking infrastructure rely heavily on data and data-driven models to predict their impact and guide their implementation. In the current work, we provide a quantitative study of the parking supply and freight vehicle drivers’ parking behaviour at urban retail malls. Methods We use as case studies two typical urban retail malls located in Singapore, and collect detailed data on freight vehicles delivering or picking up goods at these malls. Insights from this data collection effort are relayed as data stories. We first describe the parking facility at a mall as a queueing system, where freight vehicles are the agents and their decisions are the parking location choice and the parking duration. Results Using the data collected, we analyse (i) the arrival rates of vehicles at the observed malls, (ii) the empirical distribution of parking durations at the loading bays, (iii) the factors that influence the parking duration, (iv) the empirical distribution of waiting times spent by freight vehicle queueing to access the loading bay, and (v) the driver parking location choices and how this choice is influenced by system congestion. Conclusions This characterisation of freight driver behaviour and parking facility system performance enables one to understand current challenges, and begin to explore the feasibility of freight parking and loading bay management solutions.

Document type: Article