Scipedia: Documents published in 2019

Integrating mobility data sources to define and quantify a vehicle-level congestion indicator: an application for the city of Turin

Scipedia content — Mon, 15 Feb 2021 11:55:48 +0100

Purpose Traffic congestion is a large-scale problem in urban areas all over the world that can lead to substantial costs for travellers and business operations. This paper focus on how to measure the way in which congestion selectively affects different traffic streams, with special emphasis on light duty vehicles travelling around a city. Methods The idea is to integrate a dataset collecting Global Positioning System (GPS) vehicle traces with road side data sources related to traffic conditions in a road network, which on the other hand usually lack focus on specific traffic streams. The core of the data integration method is the creation of a specific indicator focusing on the time lost in congestion. This is a Key Performance Indicator (KPI) of an urban network that is of paramount importance as a decision support tool for policy makers, also because it has an impact on other key issues such as air pollution, noise emissions, energy efficiency and health problems. Then, a method is proposed to quantify the congestion KPI in a highly disaggregated fashion (each single vehicle travelling on each single link or street segment). Results This KPI can be used to inform a wide range of policy actions within the transport sector, both from the viewpoint of a city and from that of an individual actor of the transport system, such as the operator of a fleet of vehicles for urban freight deliveries. Some preliminary examples of how the aggregation of the KPI at different scales can provide insights into the transport system are presented.

Document type: Article

Experimental Verification of Fault Tolerant Operation Focusing on DC-Bus Battery Failure in Dual Inverter Motor Drive

Scipedia content — Mon, 15 Feb 2021 11:55:33 +0100

Recently, a dual inverter motor drive feeding an open-end winding permanent magnet (PM) motor has been studied, aiming for the improvement of total efficiency and a fault tolerant function of hybrid and electric vehicles. The authors have studied the fault tolerant operation of the DC-bus battery, where the failed inverter is operated only with a capacitor across the DC-bus and a space vector modulation (SVM) is employed to regulate the capacitor voltage. In our previous research, the SVM techniques for the fault tolerant operation in a low-modulation-index have been proposed. However, it was difficult to have fault tolerance in a high-modulation-index case. The voltage margin in the fault situation is limited because the failed inverter is operated with the capacitor. In this paper, the SVM technique to achieve the fault tolerant operation in the high-modulation-index state is investigated. The novel point of this paper is that the proposed technique introduces a field-weakening control in order to reduce the command voltage vector within the controllable voltage region. The proposed technique was verified through experimental tests and its operational characteristics were compared with the normal operation, from the viewpoints of the total harmonic distortion (THD) and the efficiencies of the inverters and the motor.

Document type: Article

Effect of nozzle geometry on critical-subcritical flow transitions

Scipedia content — Mon, 15 Feb 2021 11:54:22 +0100

The geometry of converging-diverging nozzles affects the conditions at which critical-subcritical flow transition occurs. The objective of this work is to develop guidelines to identify the optimum nozzle geometry that maximizes critical pressure ratio while minimizing pressure drop across the nozzle. Experiments were conducted in a facility with 1.5 in. ID PVC pipelines and a 30 ft. long lateral pipeline section. In total, 27 different nozzle geometries were tested, divided into two groups – conical and parabolic nozzles. Nozzles from the ASTAR, Deich, LJ and Moby Dick nozzle groups showed improved performance compared to other nozzle groups. It was determined that a smaller diverging angle and absence of an elongated throat resulted in a higher critical pressure ratio. Length of converging and diverging sections of nozzles did not have as much of an impact on nozzle performance as the throat diameter and shape of converging and diverging sections.

Document type: Article

Transport System Models and Big Data: Zoning and Graph Building with Traditional Surveys, FCD and GIS

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

The paper deals with the integration of data provided from traditional transport surveys (small data) with big data, provided from Information and Communication Technology (ICT), in building Transport System Models (TSMs). Big data are used to observe historical mobility patterns and transport facilities and services, but they are not able to assess ex-ante effects of planned interventions and policies. To overcome these limitations, TSMs can be specified, calibrated and validated with small data, but they are expensive to obtain. The paper proposes a procedure to increase the benefits of TSMs’ building in forecasting capabilities, on one side; and limiting the costs connected to traditional surveys thanks to the availability of big data, on the other side. Small data (e.g., census data) are enriched with Floating Car Data (FCD). At the current stage, the procedure focuses on two specific elements of TSMs: zoning and graph building. These processes are both executed considering the estimated values of an intensity function of FCDs, consistently with traditional methods based on small data. The data-fusion of small and big data, operated with a Geographic Information System (GIS) tool, in a real extra-urban context is presented in order to validate the proposed procedure.

Document type: Article

Impact of Transport Cost and Travel Time on Trade under China-Pakistan Economic Corridor (CPEC)

Scipedia content — Mon, 15 Feb 2021 10:59:50 +0100

China is the second biggest economy in the world and almost 40% of its trade in 2016 is transported through the South China Sea. China needs a small, secure, and low-cost path to trade with Europe and the Middle East and China-Pakistan Economic Corridor (CPEC) is a feasible solution to this requirement. This research analyzes the effect of CPEC on trade in terms of transport cost and travel time. In addition, the study compares the existing routes and the new CPEC route. The research methodology consists of qualitative and descriptive statistical methods. The variables (transport cost and travel time) are calculated and compared for both the existing route and new CPEC route. The results show that transport cost for 40-foot container between Kashgar and destination ports in the Middle East is decreased by about $1450 dollars and for destination ports in Europe is decreased by $1350 dollars. Additionally, travel time is decreased by 21 to 24 days for destination ports in the Middle East and 21 days for destination ports in Europe. The distance from Kashgar to destination ports in the Middle East and Europe is decreased by 11,000 to 13,000 km.

Document type: Article

Identifying Vehicle and Collision Impact by Applying the Principle of Conservation of Mechanical Energy

Scipedia content — Mon, 15 Feb 2021 10:59:34 +0100

"jats:p"Various methodologies and tools applied to identification of vehicle and collision impact seek to present more and more accurate solutions to reproduce, restore, recreate and investigate the casualty. Modern computer technology and software provide the tools to solve specific problems developing mathematical modelling of complex mechanical systems involving vehicles and other objects in a road accident. Scientists generally utilize the Standard Test Method for Impact Testing calculating the energy of deformation of both vehicles, however, one of its limitations is the evaluation of the kinetic energy of the vehicles in post-collision taking into consideration vehicle rotation and linear displacement. To improve the analysis, dynamic traffic simulation is used, taking into account the variations in the coefficient of friction, suspension elasticity and damping. The proposed method is based on a system of two equations derived from two principles: the Principle of Conservation of Mechanical Energy and the Principle of Conservation of Momentum in the impact phase. The new approach is conducted on mathematical modelling and computer simulation of vehicle motion after the impact, wherefrom the linear and angular velocities are analysed. This is achieved by the numerical solution of the differential equations of motion of the cars after the impact, and the given initial conditions that satisfy the solution are used to solve the system of equations. The main findings of the study can be grouped as follows: 1) The positions of the vehicles prior to the moment of first impact and the post-impact orientation of velocity vectors are more precise. 2) The variability of the tire-road friction coefficient is taken into consideration. 3) The value of coefficient of restitution according to Newton’s theory of impact is unnecessarily determined.

Document type: Article

A Hybrid Approach Based on Variational Mode Decomposition for Analyzing and Predicting Urban Travel Speed

Scipedia content — Mon, 15 Feb 2021 10:57:58 +0100

Predicting travel speeds on urban road networks is a challenging subject due to its uncertainty stemming from travel demand, geometric condition, traffic signals, and other exogenous factors. This uncertainty appears as nonlinearity, nonstationarity, and volatility in traffic data, and it also creates a spatiotemporal heterogeneity of link travel speed by interacting with neighbor links. In this study, we propose a hybrid model using variational mode decomposition (VMD) to investigate and mitigate the uncertainty of urban travel speeds. The VMD allows the travel speed data to be divided into orthogonal and oscillatory sub-signals, called modes. The regular components are extracted as the low-frequency modes, and the irregular components presenting uncertainty are transformed into a combination of modes, which is more predictable than the original uncertainty. For the prediction, the VMD decomposes the travel speed data into modes, and these modes are predicted and summed to represent the predicted travel speed. The evaluation results on urban road networks show that, the proposed hybrid model outperforms the benchmark models both in the congested and in the overall conditions. The improvement in performance increases significantly over specific link-days, which generally are hard to predict. To explain the significant variance of the prediction performance according to each link and each day, the correlation analysis between the properties of modes and the performance of the model are conducted. The results on correlation analysis show that the more variance of nondaily pattern is explained through the modes, the easier it was to predict the speed. Based on the results, discussions on the interpretation on the correlation analysis and future research are presented.

Document type: Article

Newly Developed Motor Cooling Method Using Refrigerant

Scipedia content — Mon, 15 Feb 2021 10:55:35 +0100

One of the greatest issues for electric vehicles such as an electric vehicle (EV), a hybrid vehicle (HV), a plug-in hybrid electric vehicle (PHEV) and a fuel cell vehicle (FCV) is further improvement of effective motor cooling, since higher rated torque is achieved with higher cooling performance. In this paper, we introduce and propose a newly developed motor cooling method we tested using refrigerant, comparing with conventional water cooling. Test results show higher cooling performance of refrigerant cooling, which achieved the rated torque 60% higher than that of water cooling.

Document type: Article

Experimental and numerical modeling of horizontally-bent buried pipelines crossing fault slip

Scipedia content — Mon, 15 Feb 2021 10:55:10 +0100

The behavior and response of pipelines subjected to slip fault movement is studied by numerical simulations as well as experimental setup. A finite element modeling is also developed via ABAQUS software. In this study, an artificial accelerogram is applied to the system and matched against the response spectrum according to the standard No. 2800 (Iranian code of practice for seismic resistant design of buildings, 2014). Three different pipe nominal sizes and thicknesses (1 ½”, 2” and 4”) are considered in the experiments on the shaking table. According to the results, plastic hinge as well as the extremum stress and strain is formed in the fixed soil wedge and at locations close to the fault line. Further, as the pipe D/t ratio increases, the plastic hinge forms further away from the fault line. According to the results, the pipe-soil strain ratio (εp/s) has lower values at larger pipe diameters. Also, the axial strains would be greater for the systems with higher (εp/s) ratios.

Document type: Article

An Empirical Study on the Comprehensive Optimization Method of a Train Diagram of the China High Speed Railway Express

Scipedia content — Mon, 15 Feb 2021 10:54:05 +0100

The rapid and stable development of China’s economy has driven the increasing demand for express transportation. Based on network operation, China Railway Corporation of High-speed Railway launched high-speed rail products, which have attracted wide attention from all walks of life. With the application of high-speed express trains, the market structure of express transportation in China will change dramatically, from highways as the main mode of transportation to high-speed railway transportation relying on a high-speed railway network, which will effectively reduce the environmental pollution caused by express transportation and further improve the sustainable development of the economy and the logistics industry. At present, the freight Electric Multiple Units (EMU) has been successfully developed and has entered the final test stage. In the last paper, we have introduced the theory and method of the high-speed rail express train operation plan. In addition, a train diagram is an important foundation of railway transportation organization. In order to ensure the sustainable development of high-speed rail express trains after they are put into use, based on the operation plan of high-speed rail express trains, this paper establishes a comprehensive compilation model of a high-speed rail express train diagram, considering train running time, freight flow distribution scheme, and the operation plan of freight multiple units, and an exact solution algorithm based on the Lagrange relaxation algorithm is designed. The computational results are encouraging and demonstrate the effectiveness of the model and solution method.

Document type: Article

Fuel Switch to LNG in Heavy Truck Traffic

Scipedia content — Mon, 15 Feb 2021 10:53:14 +0100

Liquefied natural gas (LNG) use as a fuel in road and maritime traffic has increased rapidly, and it is slowly entering railroad traffic as well. The trend was pushed by the state administrations of mainly EU countries and international organizations seeing LNG as a cost-effective and environmentally friendly alternative to diesel. Different infrastructural projects for the widespread use of LNG in transport have been launched around the world. The main goal of this paper was to analyze use of LNG as a fuel for heavy trucks. Different aspects of LNG chain were analyzed along with economical and ecological benefits of LNG application. Filling stations network for LNG were described for the purpose of comparative analysis of diesel and LNG heavy trucks. Conclusion has shown that using LNG as propellant fuel has numerous advantages over the use of conventional fuels. The higher initial investment of the LNG road vehicles could be amortized in their lifetime use, and in the long-term they are more affordable than the classic diesel vehicles. In addition to cost-effectiveness, LNG road vehicles reduce CO2 emissions. Therefore, the environmental goals in transport, not only of the member states but worldwide, could not be met without LNG in heavy truck traffic.

Document type: Article

Distributed Acoustic Sensing Using Chirped-Pulse Phase-Sensitive OTDR Technology

Scipedia content — Mon, 15 Feb 2021 10:52:57 +0100

In 2016, a novel interrogation technique for phase-sensitive (Φ)OTDR was mathematically formalized and experimentally demonstrated, based on the use of a chirped-pulse as a probe, in an otherwise direct-detection-based standard setup: chirped-pulse (CP-)ΦOTDR. Despite its short lifetime, this methodology has now become a reference for distributed acoustic sensing (DAS) due to its valuable advantages with respect to conventional (i.e., coherent-detection or frequency sweeping-based) interrogation strategies. Presenting intrinsic immunity to fading points and using direct detection, CP-ΦOTDR presents reliable high sensitivity measurements while keeping the cost and complexity of the setup bounded. Numerous technique analyses and contributions to study/improve its performance have been recently published, leading to a solid, highly competitive and extraordinarily simple method for distributed fibre sensing. The interesting sensing features achieved in these last years CP-ΦOTDR have motivated the use of this technology in diverse applications, such as seismology or civil engineering (monitoring of pipelines, train rails, etc.). Besides, new areas of application of this distributed sensor have been explored, based on distributed chemical (refractive index) and temperature-based transducer sensors. In this review, the principle of operation of CP-ΦOTDR is revisited, highlighting the particular performance characteristics of the technique and offering a comparison with alternative distributed sensing methods (with focus on coherent-detection-based ΦOTDR). The sensor is also characterized for operation in up to 100 km with a low cost-setup, showing performances close to the attainable limits for a given set of signal parameters [≈tens-hundreds of pe/sqrt(Hz)]. The areas of application of this sensing technology employed so far are briefly outlined in order to frame the technology.

This work was supported by project FINESSE MSCA-ITN-ETN-722509; the DOMINO Water JPI project under the WaterWorks2014 cofounded call by EC Horizon 2020 and Spanish MINECO; Comunidad de Madrid and FEDER Program under grant SINFOTON2-CM: P2018/NMT-4326; the Spanish Government under projects TEC2015-71127-C2-2-R and RTI2018-097957-B-C31. M.R.F.M and H.F.M. acknowledge financial support from the Spanish MICINN under contracts no. FJCI-2016-27881 and IJCI-2017-33856, respectively.

Peer reviewed

Document type: Article

Application of Lagrange Relaxation to Decentralized Optimization of Dispatching a Charging Station for Electric Vehicles

Scipedia content — Mon, 15 Feb 2021 10:49:04 +0100

To improve the computation efficiency of optimally dispatching large-scale cluster electric vehicles (EVs) and to enhance the profit of a charging station (CS) for EVs, this study investigates the optimal dispatch of the CS based on a decentralized optimization method and a time-of-use (TOU) price strategy. With the application of the Lagrange relaxation method (LRM), a decentralized optimization model with its solution is proposed that converts the traditional centralized optimization model into certain sub-problems. The optimization model aims to maximize the profit of CS, but it comprehensively considers the charging preference of EV users, the operation constraints of the distribution network, and the TOU strategy adopted by the CS. To validate the proposed decentralized optimal dispatching method, a series of numerical simulations were conducted to demonstrate its effect on the computation efficiency and stability, the profit of the CS, and the peak-load shifting. The result indicates that the TOU strategy markedly increases the profit of the CS in comparison with the fixed electricity price mechanism, and the computation efficiency and stability are much better than those of the centralized optimization method. Although it does not compensate the load fluctuation completely, the proposed method with the TOU strategy is helpful for filling the valley of power use.

Document type: Article

A Time-Space Network Model Based on a Train Diagram for Predicting and Controlling the Traffic Congestion in a Station Caused by an Emergency

Scipedia content — Mon, 15 Feb 2021 10:46:58 +0100

Timely predicting and controlling the traffic congestion in a station caused by an emergency is an important task in railway emergency management. However, traffic forecasting in an emergency is subject to a dynamic service network, with uncertainty surrounding elements such as the capacity of the transport network, schedules, and plans. Accurate traffic forecasting is difficult. This paper proposes a practical time&ndash

space network model based on a train diagram for predicting and controlling the traffic congestion in a station caused by an emergency. Based on the train diagram, we constructed a symmetric time&ndash

space network for the first time by considering the transition of the railcar state. On this basis, an improved A* algorithm based on the railcar flow route was proposed to generate feasible path sets and a dynamic railcar flow distribution model was built to simulate the railcar flow distribution process in an emergency. In our numerical studies, these output results of our proposed model can be used to control traffic congestion.

Document type: Article

An Overview of Vehicular Communications

Scipedia content — Mon, 15 Feb 2021 10:46:37 +0100

The transport sector is commonly subordinate to several issues, such as traffic congestion and accidents. Despite this, in recent years, it is also evolving with regard to cooperation between vehicles. The fundamental objective of this trend is to increase road safety, attempting to anticipate the circumstances of potential danger. Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I) and Vehicle-to-Everything (V2X) technologies strive to give communication models that can be employed by vehicles in different application contexts. The resulting infrastructure is an ad-hoc mesh network whose nodes are not only vehicles but also all mobile devices equipped with wireless modules. The interaction between the multiple connected entities consists of information exchange through the adoption of suitable communication protocols. The main aim of the review carried out in this paper is to examine and assess the most relevant systems, applications, and communication protocols that will distinguish the future road infrastructures used by vehicles. The results of the investigation reveal the real benefits that technological cooperation can involve in road safety.

Document type: Article

Ride Hub with Renewable Energy Source

Scipedia content — Mon, 15 Feb 2021 10:46:22 +0100

electric vehicles&rsquo

penetration increases, more impacts on urban systems are observed and related to both driving (e.g., on traffic congestion and reduced pollution) and charging (e.g., on the electrical grid). Therefore, there is a need to design coupled incentive mechanisms. To propose and numerically evaluate such incentives, a game theory model is adopted. Its originality comes from the coupling between the charging cost and the driving decisions: to drive downtown or to charge at an e-Park &

Ride hub with solar panels and then take public transport, in order to reach destination. Optimal ticket fares and solar park&rsquo

s size are computed using real photovoltaic production data.

Document type: Article

Novel Parameterized Utility Function on Dual Hesitant Fuzzy Rough Sets and Its Application in Pattern Recognition

Scipedia content — Mon, 15 Feb 2021 10:44:40 +0100

Based on comparative studies on correlation coefficient theory and utility theory, a series of rules that utility functions on dual hesitant fuzzy rough sets (DHFRSs) should satisfy, and a kind of novel utility function on DHFRSs are proposed. The characteristic of the introduced utility function is a parameter, which is determined by decision-makers according to their experiences. By using the proposed utility function on DHFRSs, a novel dual hesitant fuzzy rough pattern recognition method is also proposed. Furthermore, this study also points out that the classical dual tool is suitable to cope with dynamic data in exploratory data analysis situations, while the newly proposed one is suitable to cope with static data in confirmatory data analysis situations. Finally, a medical diagnosis and a traffic engineering example are introduced to reveal the effectiveness of the newly proposed utility functions on DHFRSs.

Document type: Article

Dimensionality of an urban transport system based on ISO 37120 indicators for the case of selected European cities

Scipedia content — Mon, 15 Feb 2021 10:42:11 +0100

"jats:p"The study aims to assess transport systems in terms of ISO 37120 indicators in selected European cities. Using the principal components analysis, the research identified significantly correlated variables associated with urban transport. Three principal components explained almost 87% of input data variability. The first principal component was mainly related to transportation fatalities, the second component — to the length of bicycle paths, and the third component — to the length of the network used by light passenger public transport. A strong correlation was found between the length of high capacity public transport and transportation fatalities. Furthermore, the analysis proved that the Aalter transport system was an outlier. The paper concludes by identifying several recommendations on the improvement of urban transport management and the development of low-carbon mobility systems.

Document type: Article

A Study of Taxi Service Mode Choice Based on Evolutionary Game Theory

Scipedia content — Mon, 15 Feb 2021 10:41:57 +0100

The emergence of online car-hailing service provides an innovative approach to vehicle booking but has negatively influenced the taxi industry in China. This paper modeled taxi service mode choice based on evolutionary game theory (EGT). The modes included the dispatching and online car-hailing modes. We constructed an EGT framework, including determining the strategies and the payoff matrix. We introduced different behaviors, including taxi company management, driver operation, and passenger choice. This allowed us to model the impact of these behaviors on the evolving process of service mode choice. The results show that adjustments in taxi company, driver, and passenger behaviors impact the evolutionary path and convergence speed of our evolutionary game model. However, it also reveals that, regardless of adjustments, the stable states in the game model remain unchanged. The conclusion provides a basis for studying taxi system operation and management.

Document type: Article

Preferences in regional public transport: a literature review

Scipedia content — Mon, 15 Feb 2021 10:40:42 +0100

The purpose of this article is to analyse quality attributes of regional public transport and their influence on modal choice, demand, and customer satisfaction through a literature review. The review is based on a working definition of regional public transport with boundaries toward local as well as interregional public transport: Regional public transport (i) targets passengers travelling between separate urban areas or to rural areas and (ii) a majority of the trips are made on a regular basis. Our results suggest that preferences of regional travellers mainly conform to the preferences of local travellers, but some important differences have been revealed. Most notably, on-board comfort is a higher priority for regional travellers and is increasingly important with longer travel times. Network coverage and coordination are also more prominent features of regional public transport, presumably due to the more dispersed nature of regional public transport networks. These differences, and the fact that the prerequisites for regional public transport are in general substantially different compared to local and interregional public transport, support continued use of this categorisation in public transport research. We also conclude that there is a requirement for more knowledge about the specifics of regional public transport, as public transport research, thus far, has been largely focused on local travel. Research areas of particular interest are on-board comfort, operational aspects, travel time improvements, how the environmental impact of public transport services affects modal choice, and the influence of trip length on passenger preferences.

Document type: Article

The Situation and Development Strategies for Environmental Protection Standardization in Transportation Industry of China

Scipedia content — Mon, 15 Feb 2021 10:40:14 +0100

Standardization for environmental protection in the transportation industry is an important driving force for the development of green transportation. This study introduces the current status and main problems of environmental protection standardization in transportation. In addition, major countermeasures, such as strengthening the system construction and basic support, are studied and proposed to provide theoretical support and research basis for future standardization in related areas.

Document type: Article

Application of Nonnegative Tensor Factorization for Intercity Rail–Air Transport Supply Configuration Pattern Recognition

Scipedia content — Mon, 15 Feb 2021 10:36:34 +0100

With the rapid expansion of the railway represented by high-speed rail (HSR) in China, competition between railway and aviation will become increasingly common on a large scale. Beijing, Shanghai, and Guangzhou are the busiest cities and the hubs of railway and aviation transportation in China. Obtaining their supply configuration patterns can help identify defects in planning. To achieve that, supply level is proposed, which is a weighted supply traffic volume that takes population and distance factors into account. Then supply configuration can be expressed as the distribution of supply level over time periods with different railway stations, airports, and city categories. Furthermore, nonnegative tensor factorization (NTF) is applied to pattern recognition by introducing CP (CANDECOMP/PARAFAC) decomposition and the block coordinate descent (BCD) algorithm for the selected data set. Numerical experiments show that the designed method has good performance in terms of computation speed and solution quality. Recognition results indicate the significant pattern characteristics of rail&ndash

air transport for Beijing, Shanghai, and Guangzhou are extracted, which can provide some theoretical references for practical policymakers.

Document type: Article

Metallurgical Aspects in the Welding of Clad Pipelines—A Global Outlook

Scipedia content — Mon, 15 Feb 2021 10:35:29 +0100

In the present work, the metallurgical changes in the welding of clad pipelines are studied. Clad pipes consist of a complex multi-material system, with (i) the clad being stainless steel or a nickel-based superalloy, (ii) the pipe being API X60 or X65 high-strength carbon steel, and (iii) the welding wire being a nickel-based superalloy or stainless steel in the root and hot pass, with a nickel or iron buffer layer, followed by filling with carbon steel wire. Alternatively, the corrosion resistant alloy may be used only. During production of the clad pipe, at the diffusion bonding temperature, substantial material changes may occur. These are carbon diffusion from the carbon steel to the clad, followed by the formation of hard martensite at the interface on cooling. The solidification behavior and microstructure evolution in the weld metal and in the heat-affected zone are further discussed for the different material combinations. Solidification behavior was also numerically estimated to show solidification parameters and resulting solidification modes.

Document type: Article

Short-Term Load Forecasting for Electric Vehicle Charging Stations Based on Deep Learning Approaches

Scipedia content — Mon, 15 Feb 2021 10:33:40 +0100

Short-term load forecasting is a key task to maintain the stable and effective operation of power systems, providing reasonable future load curve feeding to the unit commitment and economic load dispatch. In recent years, the boost of internal combustion engine (ICE) based vehicles leads to the fossil fuel shortage and environmental pollution, bringing significant contributions to the greenhouse gas emissions. One of the effective ways to solve problems is to use electric vehicles (EVs) to replace the ICE based vehicles. However, the mass rollout of EVs may cause severe problems to the power system due to the huge charging power and stochastic charging behaviors of the EVs drivers. The accurate model of EV charging load forecasting is, therefore, an emerging topic. In this paper, four featured deep learning approaches are employed and compared in forecasting the EVs charging load from the charging station perspective. Numerical results show that the gated recurrent units (GRU) model obtains the best performance on the hourly based historical data charging scenarios, and it, therefore, provides a useful tool of higher accuracy in terms of the hourly based short-term EVs load forecasting.

Document type: Article

Discussing and Analyzing “Maritime Cohesion” in MSP, to Achieve Sustainability in the Marine Realm

Scipedia content — Mon, 15 Feb 2021 10:33:06 +0100

Whilst the Sustainable Development Goal (SDG) 14 promotes the conservation and sustainable use of the seas, oceans and marine resources for sustainable development, decisions in ecosystem-based Maritime Spatial Planning (MSP) follow annoying and costly trade-offs and this may negatively impact its acceptance. To address conflicts and cumulative impacts and favor, as much as possible, interfering of marine activities, positive coordination and win-win options, it is necessary to develop integrated and cohesive planning approaches and new management tools. In this article, a conceptual framework of &ldquo

maritime cohesion&rdquo

is being developed mostly applicable to peopled and crowded seas and a set of relevant indicators to assess it, is proposed. It is based on the triple-model of interdependent components such as &ldquo

maritime spatial efficiency&rdquo

, &ldquo

maritime spatial quality&rdquo

and &ldquo

maritime spatial identity&rdquo

, taking into account the &ldquo

territorial cohesion&rdquo

equivalent, promoted by the Cohesion Policy. Then, in order to broadly analyze the &ldquo

spatial efficiency&rdquo

component, the &ldquo

multi-use&rdquo

concept and management tools, recently given particular emphasis by EU Blue Growth Strategy, are examined thoroughly, using the relevant literature. This article highlights constructive use of &ldquo

with the multi-use MSP paradigm as key part of &ldquo

narrative and posits that its huge and extensive potential can stimulate dynamic, collaborative, cohesive and assemblage thinking in the MSP process and be the &ldquo

spearhead&rdquo

to balance economic, social, environmental and cultural aspirations in maritime planning to achieve sustainability in the marine realm.

Document type: Article

Toward a Comfortable Driving Experience for a Self-Driving Shuttle Bus

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

The convergence of mechanical, electrical, and advanced ICT technologies, driven by artificial intelligence and 5G vehicle-to-everything (5G-V2X) connectivity, will help to develop high-performance autonomous driving vehicles and services that are usable and convenient for self-driving passengers. Despite widespread research on self-driving, user acceptance remains an essential part of successful market penetration

this forms the motivation behind studies on human factors associated with autonomous shuttle services. We address this by providing a comfortable driving experience while not compromising safety. We focus on the accelerations and jerks of vehicles to reduce the risk of motion sickness and to improve the driving experience for passengers. Furthermore, this study proposes a time-optimal velocity planning method for guaranteeing comfort criteria when an explicit reference path is given. The overall controller and planning method were verified using real-time, software-in-the-loop (SIL) environments for a real-time vehicle dynamics simulation

the performance was then compared with a typical planning approach. The proposed optimized planning shows a relatively better performance and enables a comfortable passenger experience in a self-driving shuttle bus according to the recommended criteria.

Document type: Article

Street Network Models and Measures for Every U.S. City, County, Urbanized Area, Census Tract, and Zillow-Defined Neighborhood

Scipedia content — Mon, 15 Feb 2021 10:30:56 +0100

OpenStreetMap provides a valuable crowd-sourced database of raw geospatial data for constructing models of urban street networks for scientific analysis. This paper reports results from a research project that collected raw street network data from OpenStreetMap using the Python-based OSMnx software for every U.S. city and town, county, urbanized area, census tract, and Zillow-defined neighborhood. It constructed nonplanar directed multigraphs for each and analyzed their structural and morphological characteristics. The resulting data repository contains over 110,000 processed, cleaned street network graphs (which in turn comprise over 55 million nodes and over 137 million edges) at various scales—comprehensively covering the entire U.S.—archived as reusable open-source GraphML files, node/edge lists, and GIS shapefiles that can be immediately loaded and analyzed in standard tools such as ArcGIS, QGIS, NetworkX, graph-tool, igraph, or Gephi. The repository also contains measures of each network’s metric and topological characteristics common in urban design, transportation planning, civil engineering, and network science. No other such dataset exists. These data offer researchers and practitioners a new ability to quickly and easily conduct graph-theoretic circulation network analysis anywhere in the U.S. using standard, free, open-source tools.

Document type: Article

Experimental and Numerical Study on the Strain Behavior of Buried Pipelines Subjected to an Impact Load

Scipedia content — Mon, 15 Feb 2021 10:30:40 +0100

Long-distance oil and gas pipelines are inevitably impacted by rockfalls during geologic hazards such as mud-rock flow and landslides, which have a serious effect on the safe operation of pipelines. In view of this, an experimental and numerical study on the strain behavior of buried pipelines under the impact load of rockfall was developed. The impact load exerted on the soil, and the strains of buried pipeline caused by the impact load were theoretically derived. A scale model experiment was conducted using a self-designed soil-box to simulate the complex geological conditions of the buried pipeline. The simulation model of hammer&ndash

soil&ndash

pipeline was established to investigate the dynamic response of the buried pipeline. Based on the theoretical, experimental, and finite element analysis (FEA) results, the overall strain behavior of the buried pipeline was obtained and the effects of parameters on the strain developments of the pipelines were analyzed. Research results show that the theoretical calculation results of the impact load and the peak strain were in good agreement with the experimental and FEA results, which indicates that the mathematical formula and the finite element models are accurate for the prediction of pipeline response under the impact load. In addition, decreasing the diameter, as well as increasing the wall thickness of the pipeline and the buried depth above the pipeline, could improve the ability of the pipeline to resist the impact load. These results could provide a reference for seismic design of pipelines in engineering.

Document type: Article

Reversible Transitions in a Cellular Automata-Based Traffic Model with Driver Memory

Scipedia content — Mon, 15 Feb 2021 10:28:30 +0100

Here, we develop a new cellular automata-based traffic model. In this model, individual vehicles cannot estimate global traffic flows but can only detect the vehicle ahead. Each vehicle occasionally adjusts its velocity based on the distance to the vehicle in front. Our model generates reversible phase transitions in the vehicle flux over a wide range of vehicle densities, and the traffic system undergoes scale-free evolution with respect to the flux. We thus believe that our model reveals the relationship between the macro-level flows and micro-level mechanisms of multi-agent systems for handling traffic congestion, and illustrates how drivers’ decisions impact free and congested flows.

Document type: Article

The Tendency of Urban Stakeholders to Adopt Sustainable Logistics Measures on the Example of a Polish Metropolis

Scipedia content — Mon, 15 Feb 2021 10:27:17 +0100

The scale of policies and measures for sustainable urban freight transport in European cities is still insignificant. However, the situation is changing as more and more cities are adopting sustainable urban logistics plans (SULPs). The situation in cities is extremely heterogeneous, so it would be difficult to point to one single policy that fits all. Yet the tool created with European projects constituting an instruction to prepare SULP allows us to follow the standardized steps, regardless of the conditions found in particular cities. The effectiveness of implementing sustainable measures to a large extent depends on the level of acceptability of individual urban space stakeholders. The article presents the results of a survey conducted among stakeholders of a Polish metropolis&mdash

the Gdansk&ndash

Gdynia&ndash

Sopot metropolitan area. The analysis showed that acceptability rises with the increase in the size of the surveyed entities. The most diversified acceptability ratings were obtained for the transport infrastructure solutions. Proposals for Information and Communication Technologies (ICT) solutions are rated more positively by medium-sized and large enterprises. These solutions are assessed with greater caution by small and micro enterprises. The least diversified and clearly higher acceptance indicators were obtained for proposals in the scope of shaping sustainable urban transport development. The assessments obtained from the respondents should therefore constitute an important element of the works for developing the sustainable urban logistics plans starting in 2020 for Gdynia and also the opinions can be an important element of the future sustainable urban logistics plans, which are currently being developed in many European cities.

Document type: Article

Intelligent Hydrogen Fuel Cell Range Extender for Battery Electric Vehicles

Scipedia content — Mon, 15 Feb 2021 10:26:24 +0100

Road transport is recognized as having a negative impact on the environment. Policy has focused on replacement of the internal combustion engine (ICE) with less polluting forms of technology, including battery electric and fuel cell electric powertrains. However, progress is slow and both battery and fuel cell based vehicles face considerable commercialization challenges. To understand these challenges, a review of current electric battery and fuel cell electric technologies is presented. Based on this review, this paper proposes a battery electric vehicle (BEV) where components are sized to take into account the majority of user requirements, with the remainder catered for by a trailer-based demountable intelligent fuel cell range extender. The proposed design can extend the range by more than 50% for small BEVs and 25% for large BEVs (the extended range of vehicles over 250 miles), reducing cost and increasing efficiency for the BEV. It enables BEV manufacturers to design their vehicle battery for the most common journeys, decreases charging time to provide convenience and flexibility to the drivers. Adopting a rent and drop business model reduces the demand on the raw materials, bridging the gap in the amount of charging (refueling) stations, and extending the lifespan for the battery pack.

Document type: Article

Determining Appropriate Lane-Changing Spacing for Off-Ramp Areas of Urban Expressways

Scipedia content — Mon, 15 Feb 2021 10:25:50 +0100

Congestion has become a significant issue in recent years and has greatly affected the efficiency of urban traffic operation. Random and disorderly lane-changing behavior greatly reduces traffic capacity and safety. This paper is mainly concerned with the relationship of lane-changing spacing intervals provided by off-ramp facilities and traffic flow conditions. Through field investigations in Beijing, several typical lane-changing behaviors at off-ramp areas are analyzed. By using field traffic data and actual road geometry parameters, VISSIM-based micro-behavior simulations at off-ramp areas are implemented to obtain traffic flow conditions with different lane-changing spacing intervals and other model parameters, such as traffic volume and ratio of off-ramp vehicles. Then, the numerical relationships between traffic flow state and model parameters can be shown. The results show that with increasing traffic volume and the ratio of off-ramp vehicles, the lane-changing spacing interval required by vehicles should be increased. For the same ratio of off-ramp vehicles, if the traffic volume increases by 100 pcu/h/lane (pcu is a unit to stand for a standard passenger car), the corresponding lane-changing spacing interval should be increased by a spacing of 50–100 m to avoid increasing congestion. Based on the results of this paper, smart lane management can be implemented by optimizing lane-changing spacing intervals and lane-changing behaviors to improve traffic capacity.

Document type: Article

Nested Topology Optimization Methodology for Designing Two-Wheel Chassis

Scipedia content — Mon, 15 Feb 2021 10:25:32 +0100

Weight reduction has always been a challenge for the automotive industry, mainly to reduce consumption but also improve handling. In electric vehicle design, the battery packs, their shape and positioning are critical aspects that determine the overall weight, weight distribution and, as a consequence, the efficiency, dynamics and stability of the vehicle. This presented a new challenge, to manage this necessary and inflexible weight and volume, developing the vehicle chassis around it and in the best possible way, without compromising the overall efficiency and behaviour. In this work, a methodology for nested topology optimization has been developed which combines structural topology optimization and battery pack shaping and positioning. The new methodology is implemented, without limiting its applicability, into the framework of the commercial software Hyperstudy by Altair.

Document type: Article

Association between New Urbanization and Sustainable Transportation: A Symmetrical Coupling Perspective

Scipedia content — Mon, 15 Feb 2021 10:24:38 +0100

New urbanization (NU) and sustainable transportation (ST) are two important issues in urbanization, and their symmetrical coupling is an important factor for measuring the development of the urbanization process. To comprehensively explore the symmetrical coupling level of NU and ST in the urbanization process, this study proposed a coupling coordination degree (CCD) model and calculated the CCD values of China&rsquo

s nine metropolises using panel data from 2007 to 2016. The results showed that: (1) From the perspective of each city&rsquo

s development, the CCD values for Beijing, Tianjin and Chongqing showed a downward trend, and those for Shanghai, Guangzhou, Chengdu and Wuhan exhibited a rising trend, while the CCD values for Zhengzhou and Xi&rsquo

an fell initially and then rose gradually

(2) Based on the regions of the nine cities, the CCD values of the eastern cities and the central cities all demonstrated a growth trend, while those of the western cities were consistently lower than the central and eastern cities

however, the western cities experienced the highest growth rate. (3) Predictive results showed that the CCD levels of new urbanization and sustainable transportation in the eastern, central and western cities are projected to remain unchanged. Finally, it is expected that regionally balanced development will be realized in 2025. From the symmetrical coupling perspective, this study measured and predicted the coupling coordination level of NU and ST of nine metropolises undergoing the urbanization process, which provides a theoretical basis for effective decision-making for comprehensive and sustainable development of China&rsquo

s urbanization.

Document type: Article

Seasonal Variations and Chemical Predictors of Oxidative Potential (OP) of Particulate Matter (PM), for Seven Urban French Sites

Scipedia content — Mon, 15 Feb 2021 10:24:18 +0100

Epidemiological studies suggest that the main part of chronic effects from air pollution is likely to be linked with particulate matter (PM). Oxidative potential (OP) of PM is gaining strong interest as a promising health exposure metric. This study combined atmospheric detailed composition results obtained for seven different urban background environments over France to examine any possible common feature in OP seasonal variations obtained using two assays (acid ascorbic (AA) and dithiothreitol (DTT)) along a large set of samples ( N >

700 ). A remarkable homogeneity in annual cycles was observed with a higher OP activity in wintertime at all investigated sites. Univariate correlations were used to link the concentrations of some major chemical components of PM and their OP. Four PM components were identified as OP predictors: OC, EC, monosaccharides and Cu. These species are notably emitted by road transport and biomass burning, targeting main sources probably responsible for the measured OP activity. The results obtained confirm that the relationship between OP and atmospheric pollutants is assay- and location-dependent and, thus, the strong need for a standardized test, or set of tests, for further regulation purposes.

Document type: Article

Model tests for surge height of rock avalanche–debris flows based on momentum balance

Scipedia content — Mon, 15 Feb 2021 10:20:42 +0100

"jats:p"Rock avalanche–debris flows triggered by earthquakes commonly take place in mountainous areas. When entering a body of water, due to good fluidity they can move for some time instead of halting in water. In this study, we proposed a method for calculating the surge height of rock avalanche–debris flows based on momentum balance and designed a series of model tests to validate this method. The experimental variables include the initial water depth, landslide velocity, and landslide volume. According to the experimental results, we analyzed the maximum wave height in sliding zone based on momentum balance. In addition, we investigated the surge height and proposed the calculation method in propagating zone and running up zone. In this way, we can find out the surge height in different areas when a rock avalanche–debris flow impacts into the water, which could provide a basis for analyzing the burst of barrier lakes.

Document type: Article

Development of Technical Regulations for Fuel Cell Motorcycles in Japan—Hydrogen Safety

Scipedia content — Mon, 15 Feb 2021 10:17:11 +0100

Hydrogen fuel cell vehicles are expected to play an important role in the future and thus have improved significantly over the past years. Hydrogen fuel cell motorcycles with a small container for compressed hydrogen gas have been developed in Japan along with related regulations. As a result, national regulations have been established in Japan after discussions with Japanese motorcycle companies, stakeholders, and experts. The concept of Japanese regulations was proposed internationally, and a new international regulation on hydrogen-fueled motorcycles incorporating compressed hydrogen storage systems based on this concept are also established as United Nations Regulation No. 146. In this paper, several technical regulations on hydrogen safety specific to fuel cell motorcycles incorporating compressed hydrogen storage systems are summarized. The unique characteristics of these motorcycles, e.g., small body, light weight, and tendency to overturn easily, are considered in these regulations.

Document type: Article

An MBSE Approach for Development of Resilient Automated Automotive Systems

Scipedia content — Mon, 15 Feb 2021 10:13:32 +0100

Advanced driver assistance and automated driving systems must operate in complex environments and make safety-critical decisions. Resilient behavior of these systems in their targeted operation design domain is essential. In this paper, we describe developments in our Model-Based Systems Engineering (MBSE) approach to develop resilient safety-critical automated systems. An MBSE approach provides the ability to provide guarantees about system behavior and potentially reduces dependence on in-vehicle testing through the use of rigorous models and extensive simulation. We are applying MBSE methods to two key aspects of developing resilient systems: (1) ensuring resilient behavior through the use of Resilience Contracts for system decision making; and (2) applying simulation-based testing methods to verify the system handles all known scenarios and to validate the system against potential unknown scenarios. Resilience Contracts make use of contract-based design methods and Partially Observable Markov Decision Processes (POMDP), which allow the system to model potential uncertainty in the sensed environment and thus make more resilient decisions. The simulation-based testing methodology provides a structured approach to evaluate the operation of the target system in a wide variety of operating conditions and thus confirm that the expected resilient behavior has indeed been achieved. This paper provides details on the development of a utility function to support Resilience Contracts and outlines the specific test methods used to evaluate known and unknown operating scenarios.

Document type: Article

Examining the Walking Accessibility, Willingness, and Travel Conditions of Residents in Saudi Cities

Scipedia content — Mon, 15 Feb 2021 10:13:05 +0100

Rapid urban expansion and population growth in Saudi cities over the past four decades have increased vehicular accidents and traffic congestion and have impacted the daily walking conditions of the residents. Walking has various health and environmental benefits. In North American and European countries, three factors have been found to motivate a resident to walk within their community: their accessibility to community social and business facilities, their perception and willingness, and the safety conditions of the roads and sidewalks within their community for walking. This study examined these factors and their role in the walking habits of the residents in the neighborhoods of Doha and Dana districts in Saudi Arabia&rsquo

s eastern city of Dhahran. Data were collected through field observations and by randomly sampling and interviewing 200 residents. Geographic Information Systems (GIS) and SPSS statistical software were used for data analysis. The results show that most of the community facilities are randomly placed in the districts. Mosques are the closest facility to each resident with an average accessibility distance of 242m. Almost 43% of the respondents prefer daily walking while the rest are hesitant due to hot weather during summer and narrow and poorly designed sidewalks. The sidewalks were also found to be blocked by trees, street signals, and illegally parked vehicles. Future studies should explore the accessibility to facilities, willingness, climate, and health conditions of the residents, and the road and sidewalk conditions for walking in other cities of the Kingdom.

Document type: Article

Eco-Efficiency of a Lithium-Ion Battery for Electric Vehicles: Influence of Manufacturing Country and Commodity Prices on GHG Emissions and Costs

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

Lithium-ion battery packs inside electric vehicles represents a high share of the final price. Nevertheless, with technology advances and the growth of the market, the price of the battery is getting more competitive. The greenhouse gas emissions and the battery cost have been studied previously, but coherent boundaries between environmental and economic assessments are needed to assess the eco-efficiency of batteries. In this research, a detailed study is presented, providing an environmental and economic assessment of the manufacturing of one specific lithium-ion battery chemistry. The relevance of parameters is pointed out, including the manufacturing place, the production volume, the commodity prices, and the energy density. The inventory is obtained by dismantling commercial cells. The correlation between the battery cost and the commodity price is much lower than the correlation between the battery cost and the production volume. The developed life cycle assessment concludes that the electricity mix that is used to power the battery factory is a key parameter for the impact of the battery manufacturing on climate change. To improve the battery manufacturing eco-efficiency, a high production capacity and an electricity mix with low carbon intensity are suggested. Optimizing the process by reducing the electricity consumption during the manufacturing is also suggested, and combined with higher pack energy density, the impact on climate change of the pack manufacturing is as low as 39.5 kg CO2 eq/kWh.

Document type: Article

Optimizing the Location of Virtual Stations in Free-Floating Bike-Sharing Systems with the User Demand during Morning and Evening Rush Hours

Scipedia content — Mon, 15 Feb 2021 10:08:53 +0100

In recent years, free-floating bike-sharing systems (FFBSSs) have been considerably developed in China. As there is no requirement to construct bike stations, this system can substantially reduce the cost when compared to the traditional bike-sharing systems. However, FFBSSs have also become a critical cause of parking disorder, especially during the morning and evening rush hours. To address this issue, the local governments stipulated that FFBSSs are required to deploy virtual stations near public transit stations and major establishments. Therefore, the location assignment of virtual stations is sufficiently considered in the FFBSSs, which is required to solve the parking disorder and satisfy the user demand, simultaneously. The purpose of this study is to optimize the location assignment of virtual stations that can meet the growing demand of users by analyzing the usage data of their shared bikes. This optimization problem is generally formulated as a mixed-integer linear programming (MILP) model to maximize the user demand. As an alternative solution, this article proposes a clustering algorithm, which can solve this problem in real time. The experimental results demonstrate that the MILP model and the proposed method are superior to the K-means method. Our method not only provides a solution for maximizing the user demand but also gives an optimized design scheme of the FFBSSs that represents the characteristics of virtual stations.

Document type: Article

Electric Vehicle Fast Charging Needs in Cities and along Corridors

Scipedia content — Mon, 15 Feb 2021 10:06:39 +0100

Fast charging is seen as a means to facilitate long-distance driving for electric vehicles (EVs). As a result, roll-out planning generally takes a corridor approach. However, with higher penetration of electric vehicles in urban areas, cities contemplate whether inner-city fast chargers can be an alternative for the growing amount of slow public chargers. For this purpose, more knowledge is required in motives and preferences of users and actual usage patterns of fast chargers. Similarly, with increasing charging speeds of fast chargers and different modes (taxi, car sharing) also switching to electric vehicles, the effect of charging speed should be evaluated as well as preferences amongst different user groups. This research investigates the different intentions and motivations of EV drivers at fast charging stations to see how charging behaviour at such stations differs using both data analysis from charging stations as a survey among EV drivers. Additionally, it estimates the willingness of EV drivers to use fast charging as a substitute for on-street home charging given higher charging speeds. The paper concludes that limited charging speeds imply that EV drivers prefer parking and charging over fast charging but this could change if battery developments allow higher charging speeds.

Document type: Article

Lifecycle energy and greenhouse gas emissions analysis of biomass‐based 2‐ethylhexanol as an alternative transportation fuel

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

This study investigates the environmental performance of 2‐ethylhexanol (2‐EH), as a potential drop‐in transport fuel alternative. Three different biomass‐based production pathways are evaluated and compared using life cycle assessment (LCA) methodology. The environmental impact of 2‐EH is assessed in terms of cumulative energy demand (CED) and global warming potential (GWP). Among the three alternative pathways, 2‐EH produced via syngas results in the lowest primary energy demand and GHG emissions under the baseline assumptions of this work. The two biochemical production pathways (via ethanol and butanol) exhibit higher CED and GWP during biomass conversion steps mainly due to process materials and chemicals used. Process specifications such as transport distance to production facility or the fate of the obtained by‐products are shown to influence the overall environmental impact of the fuel for all studied pathways. The use phase performance of 2‐EH was also considered in this work, as part of a 100% renewable blend and was compared to existing fossil and renewable fuels. The studied blend has the potential to reduce GHG emissions by more than 85% compared to fossil diesel while when certain production pathways are followed, it exhibits lower GWP than renewable fuels already in the market such as ethanol blends and biodiesel. 2‐EH can therefore provide a competitive alternative to fossil transport fuels increasing the share of renewable content in the current vehicle fleet, thus enhancing the efforts for a sustainable transport sector.

Document type: Article

Vision-Based Traffic Sign Detection and Recognition Systems: Current Trends and Challenges

Scipedia content — Mon, 15 Feb 2021 10:04:12 +0100

The automatic traffic sign detection and recognition (TSDR) system is very important research in the development of advanced driver assistance systems (ADAS). Investigations on vision-based TSDR have received substantial interest in the research community, which is mainly motivated by three factors, which are detection, tracking and classification. During the last decade, a substantial number of techniques have been reported for TSDR. This paper provides a comprehensive survey on traffic sign detection, tracking and classification. The details of algorithms, methods and their specifications on detection, tracking and classification are investigated and summarized in the tables along with the corresponding key references. A comparative study on each section has been provided to evaluate the TSDR data, performance metrics and their availability. Current issues and challenges of the existing technologies are illustrated with brief suggestions and a discussion on the progress of driver assistance system research in the future. This review will hopefully lead to increasing efforts towards the development of future vision-based TSDR system.

Document type: Article

Electric Vehicle Battery Lifetime Extension through an Intelligent Double-Layer Control Scheme

Scipedia content — Mon, 15 Feb 2021 10:03:40 +0100

Electric vehicles (EVs) are recognized as promising options, not only for the decarbonization of urban areas and greening of the transportation sector, but also for increasing power system flexibility through demand-side management. Large-scale uncoordinated charging of EVs can impose negative impacts on the existing power system infrastructure regarding stability and security of power system operation. One solution to the severe grid overload issues derived from high penetration of EVs is to integrate local renewable power generation units as distributed generation units to the power system or to the charging infrastructure. To reduce the uncertainties associated with renewable power generation and load as well as to improve the process of tracking Pareto front in each time sequence, a predictive double-layer optimal power flow based on support vector regression and one-step prediction is presented in this study. The results demonstrate that, through the proposed control approach, the rate of battery degradation is reduced by lowering the number of cycles in which EVs contribute to the services that can be offered to the grid via EVs. Moreover, vehicle to grid services are found to be profitable for electricity providers but not for plug-in electric vehicle owners, with the existing battery technology and its normal degradation.

Document type: Article

Congestion, road safety, and the effectiveness of public policies in urban areas

Scipedia content — Mon, 15 Feb 2021 10:01:58 +0100

Congestion and road accidents are both considered essential challenges for sustainable mobility in large cities, but their relationship is only partially explored by the literature. In this paper, we empirically examine different public policies aimed at reducing urban traffic congestion but which may also have indirect effects on road accidents and casualties. We use data from 25 large urban areas in Spain for the period 2008&ndash

2017 and apply econometric methods to investigate how a variety of public policies do affect both negative externalities. Although the relationship between congestion and road safety is complex, we find that the promotion of certain modes of public transportation and the regulation of parking spaces may contribute to making cities more sustainable, both in terms of the time spent traveling and the probability of being affected by an accident. Considering whether policies addressing congestion improve or damage road safety as an indirect result is a useful approach for local policy-makers and planners in their attempt to get sustainable transportation outcomes.

Document type: Article

A new program for the hydraulic calculation of steam-water mixture pipelines in geothermal fields

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

A new mathematical model of steam-water flow in a pipeline, which takes into account the gravitational effect and satisfies new challenges in the development of geothermal fields with two-phase transportation of the heat carrier is presented. Taking into account the gravitational effect in the upstream flows, a method based on the “drift model”, which determines the steam velocity averaged over the crosssection was used. A similar method is proposed for downstream flows, but it determines the water velocity averaged over the cross-section. In this case, analogs of empirical coefficients were used. These coefficients determined from the condition of equality of parameters calculated using different approaches in a horizontal flow. The model was verified, which showed positive results. The proposed model significantly expands the possibilities of hydraulic calculation of steam-water mixture pipelines in geothermal fields.

Document type: Article

Strategic Planning of Cars Quality in Operation

Scipedia content — Mon, 15 Feb 2021 09:58:45 +0100

"jats:p"Attainment of high competitiveness indicators of products and services is a natural goal of each enterprise. This goal stems from the desire of stakeholders to ensure the continuous, long-term development of a company and the high performance of labour results. However, the market has leaders and outsiders for various reasons. And the outsiders can be decently prepared in organizational and technical terms. But something prevents them from successfully developing. In addition, a decision of methodological and analytical tasks is not cheap. Competent experts, relevant technical and technological support of the process, and, most importantly, the conditions for creative work are required. It is necessary effective management decisions based on the detailed analysis of warranty period of cars operation for solving main problems related to the quality and products competitiveness. Similar analytical activity is helping to improve the life circle processes, creates the opportunities to enhance customer satisfaction and sustainable development of automakers. The research has updated a problem of design and realization effective analytical tools for an appointment the quality objectives for the automotive corporations. This paper presents the results of development and implementation of the new approach to the strategic planning of products competitiveness and setting the quality objectives by the example of automotive industry.

Document type: Article

Air quality strategies and technologies: A rapid review of the international evidence.

Scipedia content — Mon, 15 Feb 2021 09:57:21 +0100

Poor air quality is a pressing policy issue that spans public health and environmental portfolios, and governments worldwide are investing in a wide array of measures to address it. This paper is a rapid review of the evidence behind air quality strategies and technologies. It was conducted according to the principles of a systematic review, and includes both academic and “grey” literature sources. It focuses on road transport in urban areas, because air pollution tends to be worse in cities, and the main source is fossil fuel vehicles. It draws on the environmental science and policy literature to provide interdisciplinary insight into the most effective air quality policy measures. The most promising initiatives include active travel infrastructure, roadside barriers, low emission zones, and low speed limits. Technologies which remove pollution from the air largely remain unproven, especially at the scale needed to make a significant impact. The combinations of policies from three cities which rank highly for air quality are reviewed; one important finding is that policies are most effective when they are a part of a mutually reinforcing suite of measures. Policies consistent across the cities studied are good public transport coverage, a good cycle network, and financial incentives for electric vehicle purchase.

Document type: Article

Optimal CHP Planning in Integrated Energy Systems considering Use-of-System Charges

Scipedia content — Mon, 15 Feb 2021 09:55:35 +0100

This paper proposes a novel optimal planning model for combined heat and power (CHP) in multiple energy systems of natural gas and electricity to benefit both networks by deferring investment for network owners and reducing use-of-system (UoS) charge for network users. The new planning model considers the technical constraints of both electricity and natural gas systems. A two-stage planning approach is proposed to determine the optimal site and size of CHPs. In the first stage, a long-run incremental cost matrix is designed to reflect CHP locational impact on both natural gas and electricity network investment, used as a criterion to choose the optimal location. In the second stage, CHP size is determined by solving an integrated optimal model with the objective to minimize total incremental network investment costs. The proposed method is resolved by the interior-point method and implemented on a practically integrated electricity and natural gas systems. Two case studies are conducted to test the performance for single and multiple CHPs cases. This paper enables cost-efficient CHP planning to benefit integrated natural gas and electricity networks and network users in terms of reduced network investment cost and consequently reduced UoS charges.

Document type: Article

Physiological Characteristics and Nonparametric Test for Master-Slave Driving Task’s Mental Workload Evaluation in Mountain Area Highway at Night

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

With the rapid development of advanced mobile intelligent terminals, driving tasks are diverse, and new traffic safety problems occur. We propose a new research on physiological characteristics and nonparametric tests for the master-slave driving task, especially for evaluation of drivers’ mental workload in mountain area highway in nighttime scenario. First, we establish the experimental platform based driving simulator and design the master-slave driving task. Second, based on the physiological data and subjective evaluation for mental workload, we use statistical methods to composite the physical changes evolution analysis in a driving simulator. Finally, we finished nonparametric test of the drivers’ psychological load and road test. The results show that in compassion with the daytime scenario, drivers should pay much effort to driving skills and risk identification in the nighttime scenario. Thus, in the same driving condition, drivers should bear the higher level of mental workload, and it has been subjected to even greater pressures and intensity of emotions.

Document type: Article

A Review of Battery State of Health Estimation Methods: Hybrid Electric Vehicle Challenges

Scipedia content — Mon, 15 Feb 2021 09:54:00 +0100

International audience; To cope with the new transportation challenges and to ensure the safety and durability of electric vehicles and hybrid electric vehicles, high performance and reliable battery health management systems are required. The Battery State of Health (SOH) provides critical information about its performances, its lifetime and allows a better energy management in hybrid systems. Several research studies have provided different methods that estimate the battery SOH. Yet, not all these methods meet the requirement of automotive real-time applications. The real time estimation of battery SOH is important regarding battery fault diagnosis. Moreover, being able to estimate the SOH in real time ensure an accurate State of Charge and State of Power estimation for the battery, which are critical states in hybrid applications. This study provides a review of the main battery SOH estimation methods, enlightening their main advantages and pointing out their limitations in terms of real time automotive compatibility and especially hybrid electric applications. Experimental validation of an online and on-board suited SOH estimation method using model-based adaptive filtering is conducted to demonstrate its real-time feasibility and accuracy.

Document type: Article

Deceleration Planning Algorithm Based on Classified Multi-Layer Perceptron Models for Smart Regenerative Braking of EV in Diverse Deceleration Conditions

Scipedia content — Mon, 15 Feb 2021 09:53:29 +0100

The smart regenerative braking system (SRS) is an autonomous version of one-pedal driving in electric vehicles. To implement SRS, a deceleration planning algorithm is necessary to generate the deceleration used in automatic regenerative control. To reduce the discomfort from the automatic regeneration, the deceleration should be similar to human driving. In this paper, a deceleration planning algorithm based on multi-layer perceptron (MLP) is proposed. The MLP models can mimic the human driving behavior by learning the driving data. In addition, the proposed deceleration planning algorithm has a classified structure to improve the planning performance in each deceleration condition. Therefore, the individual MLP models were designed according to three different deceleration conditions: car-following, speed bump, and intersection. The proposed algorithm was validated through driving simulations. Then, time to collision and similarity to human driving were analyzed. The results show that the minimum time to collision was 1.443 s and the velocity root-mean-square error (RMSE) with human driving was 0.302 m/s. Through the driving simulation, it was validated that the vehicle moves safely with desirable velocity when SRS is in operation, based on the proposed algorithm. Furthermore, the classified structure has more advantages than the integrated structure in terms of planning performance.

Document type: Article

Application of Photo-Electrochemically Generated Hydrogen with Fuel Cell Based Micro-Combined Heat and Power: A Dynamic System Modelling Study

Scipedia content — Mon, 15 Feb 2021 09:51:29 +0100

Photo-electrochemical (PEC) hydrogen generation is a promising technology and alternative to photovoltaic (PV)-electrolyser combined systems. Since there are no commercially available PEC cells and very limited field trials, a computer simulation was used to assess the efficacy of the approach for different domestic applications. Three mathematical models were used to obtain a view on how PEC generated hydrogen is able to cover demands for a representative dwelling. The analysed home was grid-connected and used a fuel cell based micro-CHP (micro-combined heat and power) system. Case studies were carried out that considered four different photo-electrode technologies to capture a range of current and possible future device efficiencies. The aim for this paper was to evaluate the system performance such as efficiency, fuel consumption and CO2 reduction capability. At the device unit level, the focus was on photo-electrode technological aspects, such as the effect of band-gap energy represented by different photo-materials on productivity of hydrogen and its uncertainty caused by the incident photon-to-current conversion efficiency (IPCE), which is highly electrode preparation specific. The presented dynamic model allows analysis of the performance of a renewable energy source integrated household with variable loads, which will aid system design and decision-making.

Document type: Article

Towards Personal Virtual Traffic Lights

Scipedia content — Mon, 15 Feb 2021 09:51:10 +0100

Traffic control management at intersections, a challenging and complex field of study, aims to strike a balance between safety and efficient traffic control. Nowadays, traffic control at intersections is typically done by traffic light systems which are not optimal and exhibit several drawbacks, such as poor efficiency and real-time adaptability. With the advent of Intelligent Transportation Systems (ITS), vehicles are being equipped with state-of-the-art technology, enabling cooperative decision-making which will certainly overwhelm the available traffic control systems. This solution strongly penalizes users without such capabilities, namely pedestrians, cyclists, and other legacy vehicles. Therefore, in this work, a prototype based on an alternative technology to the standard vehicular communications, Bluetooth Low Energy (BLE), is presented. The proposed framework aims to integrate legacy and modern vehicular communication systems into a cohesive management system. In this framework, the movements of users at intersections are managed by a centralized controller which, through the use of networked retransmitters deployed at intersections, broadcasts alerts and virtual light signalization orders. Users receive the aforementioned information on their own smart devices, discarding the need for dedicated light signalization infrastructures. Field tests, carried out with a real-world implementation, validate the correct operation of the proposed framework.

Document type: Article

Integrating Activity-Based Geographic Information and Long-Term Remote Sensing to Characterize Urban Land Use Change

Scipedia content — Mon, 15 Feb 2021 09:50:06 +0100

The land use structure is a key component to understand the complexity of urban systems because it provides a snapshot of urban dynamics and how people use space. This paper integrates socially sensed activity data with a remotely sensed land cover product in order to infer urban land use and its changes over time. We conducted a case study in the Washington D.C.&ndash

Baltimore metropolitan area to identify the pattern of land use change from undeveloped to developed land, including residential and non-residential uses for a period covering 1986&ndash

2008. The proposed approach modeled physical and behavioral features of land parcels from a satellite-based impervious surface cover change product and georeferenced Tweets, respectively. A model assessment with random forests classifiers showed that the proposed classification workflow could classify residential and non-residential land uses at an accuracy of 81%, 4% better than modeling the same land uses from physical features alone. Using the timestamps of the impervious surface cover change product, the study also reconstructed the timeline of the identified land uses. The results indicated that the proposed approach was capable of mapping detailed land use and change in an urban region, and represents a new and viable way forward for urban land use surveying that could be especially useful for surveying and tracking changes in cities where traditional approaches and mapping products (i.e., from remote sensing products) may have a limited capacity to capture change.

Document type: Article

A fault prediction method for catenary of high-speed rails based on meteorological conditions

Scipedia content — Mon, 15 Feb 2021 09:49:28 +0100

Fault frequency of catenary is related to meteorological conditions. In this work, based on the historical data, catenary fault frequency and weather-related fault rate are introduced to analyse the correlation between catenary faults and meteorological conditions, and further the effect of meteorological conditions on catenary operation. Moreover, machine learning is used for catenary fault prediction. As with the single decision tree, only a small number of training samples can be classified correctly by each weak classifier, the AdaBoost algorithm is adopted to adjust the weights of misclassified samples and weak classifiers, and train multiple weak classifiers. Finally, the weak classifiers are combined to construct a strong classifier, with which the final prediction result is obtained. In order to validate the prediction method, an example is provided based on the historical data from a railway bureau of China. The result shows that the mapping relation between meteorological conditions and catenary faults can be established accurately by AdaBoost algorithm. The AdaBoost algorithm can accurately predict a catenary fault if the meteorological conditions are provided.

Document type: Article

Phase Space Analysis of Pig Ear Skin Temperature during Air and Road Transport

Scipedia content — Mon, 15 Feb 2021 09:47:04 +0100

High or variable ambient temperature can affect thermal regulation in livestock, but few studies have studied thermal variability during air and road transport, partly due to the lack of tools to compare thermal data from a long time series over periods of different duration. In this study, we recorded the ear skin temperature (EST) of 11 Duroc breeder pigs (7 females and 4 males) during commercial intercontinental transport from Canada to Spain, which included both road and aircraft travel and lasted 65 h. The EST was measured using a logger placed inside the left ear. Phase space diagrams EST, that is EST time series vs. itself delayed in time, were used to quantify the variability of the time-temperature series based on the areas that included all the points in the phase space. Phase space areas were significantly higher for all the animals during air travel, almost doubling that of road transport. Using the phase spaces, we identified an event during air transport that lasted 57 min, leading to a general decrease in EST by 8 °

C, with respect to the average EST (34.1 °

C). We also found that thermal variability was more stable in males (F = 20.81, p = 0.0014), which were also older and heavier.

Document type: Article

The Influence of Wheelchair Users on Movement in a Bottleneck and a Corridor

Scipedia content — Mon, 15 Feb 2021 09:45:57 +0100

Emergency exits as bottlenecks in escape routes are important for designing traffic facilities. Particularly, the capacity estimation is a crucial performance criterion for assessment of pedestrians’ safety in built environments. For this reason, several studies were performed during the last decades which focus on the quantification of movement through corridors and bottlenecks. These studies were usually conducted with populations of homogeneous characteristics to reduce influencing variables and for reasons of practicability. Studies which consider heterogeneous characteristics in performance parameters are rarely available. In response and to reduce this lack of data a series of well-controlled large-scale movement studies considering pedestrians using different types of wheelchairs was carried out. As a result it is shown that the empirical relations "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"""mml:mover accent="false"""mml:mrow""mml:mi"ρ"/mml:mi""/mml:mrow""mml:mo"¯"/mml:mo""/mml:mover""mml:mo stretchy="false""("/mml:mo""mml:mover accent="false"""mml:mrow""mml:mi"v"/mml:mi""/mml:mrow""mml:mo"¯"/mml:mo""/mml:mover""mml:mo stretchy="false"")"/mml:mo""/mml:math" and "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"""mml:mover accent="false"""mml:mrow""mml:msub""mml:mrow""mml:mi"J"/mml:mi""/mml:mrow""mml:mrow""mml:mi"s"/mml:mi""/mml:mrow""/mml:msub""/mml:mrow""mml:mo"¯"/mml:mo""/mml:mover""mml:mo stretchy="false""("/mml:mo""mml:mover accent="false"""mml:mrow""mml:mi"ρ"/mml:mi""/mml:mrow""mml:mo"¯"/mml:mo""/mml:mover""mml:mo stretchy="false"")"/mml:mo""/mml:math" are strongly affected by the presence of participants with visible disabilities (such as wheelchair users). We observed an adaption of the overall movement speeds to the movement speeds of participants using a wheelchair, even for low densities and free flow scenarios. Flow and movement speed are in a complex relation and do not depend on density only. In our studies, the concept of specific flow fits for the nondisabled subpopulation but it is not valid for scenario considering wheelchair users in the population.

Document type: Article

Hardware Architecture and Configuration Parameters of a Low Weight Electronic Differential for Light Electric Vehicles with Two Independent Wheel Drive to Minimize Slippage

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

This article presents a design and performance analysis of an Electronic Differential (ED) system designed for Light Electric Vehicles (LEVs). We have developed a test tricycle vehicle with one front steering wheel and two rear fixed units in the same axis with a brushless DC (BLDC) motor integrated in each of them. Each motor has an independent controller unit and a common electronic Arduino CPU that can plan specific speeds for each wheel as curves are being traced. Different implementations of sensors (input current/torque, steering angle and speed of the wheels) are discussed related to their hardware complexity and performance based on speed level requirements and slipping on the traction wheels. Two driving circuits were generated (slalom and circular routes) and driven at different speeds, monitoring and recording all the related parameters of the vehicle. The most representative graphs obtained are presented. The analysis of these data presents a significant change of the behaviour of the control capability of the ED when the lineal speed of the vehicle makes a change of direction that passes 10 Km/h. In this situation, to obtain good performance of the ED, it is necessary to include sensors related to the wheels.

Document type: Article

Recent Advances in Pipeline Monitoring and Oil Leakage Detection Technologies: Principles and Approaches

Scipedia content — Mon, 15 Feb 2021 09:44:25 +0100

Pipelines are widely used for the transportation of hydrocarbon fluids over millions of miles all over the world. The structures of the pipelines are designed to withstand several environmental loading conditions to ensure safe and reliable distribution from point of production to the shore or distribution depot. However, leaks in pipeline networks are one of the major causes of innumerable losses in pipeline operators and nature. Incidents of pipeline failure can result in serious ecological disasters, human casualties and financial loss. In order to avoid such menace and maintain safe and reliable pipeline infrastructure, substantial research efforts have been devoted to implementing pipeline leak detection and localisation using different approaches. This paper discusses pipeline leakage detection technologies and summarises the state-of-the-art achievements. Different leakage detection and localisation in pipeline systems are reviewed and their strengths and weaknesses are highlighted. Comparative performance analysis is performed to provide a guide in determining which leak detection method is appropriate for particular operating settings. In addition, research gaps and open issues for development of reliable pipeline leakage detection systems are discussed.

Document type: Article

Deep Reinforcement Learning-Based Traffic Signal Control Using High-Resolution Event-Based Data

Scipedia content — Mon, 15 Feb 2021 09:42:32 +0100

Reinforcement learning (RL)-based traffic signal control has been proven to have great potential in alleviating traffic congestion. The state definition, which is a key element in RL-based traffic signal control, plays a vital role. However, the data used for state definition in the literature are either coarse or difficult to measure directly using the prevailing detection systems for signal control. This paper proposes a deep reinforcement learning-based traffic signal control method which uses high-resolution event-based data, aiming to achieve cost-effective and efficient adaptive traffic signal control. High-resolution event-based data, which records the time when each vehicle-detector actuation/de-actuation event occurs, is informative and can be collected directly from vehicle-actuated detectors (e.g., inductive loops) with current technologies. Given the event-based data, deep learning techniques are employed to automatically extract useful features for traffic signal control. The proposed method is benchmarked with two commonly used traffic signal control strategies, i.e., the fixed-time control strategy and the actuated control strategy, and experimental results reveal that the proposed method significantly outperforms the commonly used control strategies.

Document type: Article

KAJIAN ANGKUTAN UDARA PERINTIS KARGO DI PROPINSI PAPUA

Scipedia content — Mon, 15 Feb 2021 09:41:37 +0100

High logistics costs which may cause the price gap (disparity) between regions in Indonesia. The high cost of logistics in Papua is also caused by the topography of the area which is largely mountainous region so that the accessibility of people and goods will be very dependent on air transport. Air transport facilities and infrastructure in Papua are still inadequate. Purposes of the study is to investigate the mechanisms of implementation and monitoring subsidies pioneering air transport of cargo to optimize the cost of air freight pioneer in Papua Province. With the ever descriptive qualitative research methods. Based on the analysis and discussion of the Air Transport Pilot Study Implementation of Cargo in Papua it can be concluded the following matters: mplementation of pioneering air transport of cargo is required to reduce the price gap between regions in the district capital of Papua (Timika, Wamena and Yakuhimo) to the surrounding districts.
Of the several routes proposed by local government district in Papua, there are 11 routes that should be a priority in the implementation of pioneering air transport of cargo, ie: Timika-Beoga, Timika-Ilaga, Timika-Sinak, Timika-Kenyam, Wamena-Mugi, Wamena-Mamit, Wamena-Mapenduma, Dekai-Silimo, Dekai-Anggruk, Dekai-Korupun dan Dekai-Ubahak. Results of calculations and estimates of the type of aircraft and payload in the district of papua, it was concluded that the aircraft type DHC-6, C208B and PILATUS PC6, with a carrying capacity / payload of 800 kg / flight - 1000 kg /flight.

Document type: Article

System for Increasing the Seismic Safety of Pipelines in the Water Supply and Distribution Networks

Scipedia content — Fri, 12 Feb 2021 16:24:40 +0100

Seismic activity of small, medium or high intensity has a destructive effect on existing water supply and distribution networks. In the scholar literature, these are included in Class I&mdash

Vital Performance Systems, whose operation must be uninterrupted in case of a seismic event. Water networks are also essential for the safe operation of certain critical subsystems in the event of an earthquake (fire-extinguishing systems, etc.), in order to avoid loss of human lives, reduce adverse environmental impacts and limit damage caused by fires. The article proposes a seismic safety system for the water transport pipelines obtained by designing, executing and testing an experimental design, a system that can be used to increase the seismic resilience of the water supply and distribution network pipelines. The experimental data obtained were verified on the basis of the theoretical data available in the literature. The results of the research are particularly useful and can be proposed for use from the stage of designing new networks to providing expertise for existing networks, for establishing the most-stressed areas in which to be installed, and for implementing both execution and at the same time rehabilitation and upgrading.

Document type: Article

Research on Day-ahead Dispatch of Electricity-heat Integrated Energy System Based on Improved PSO Algorithm

Scipedia content — Fri, 12 Feb 2021 16:22:19 +0100

With the increasingly serious environmental pollution, it is of great significance to construct a comprehensive day-ahead dispatch model of the integrated energy system. For the regional electricity-heat integrated energy system, firstly analyze the operating characteristics and dispatch costs of all units in the system, and then establish the day-ahead economic dispatch model of the system. Furthermore, an improved PSO algorithm is designed based on the idea of adaptive weight and genetic algorithm, and the appropriate algorithm is used to solve the work schedule of each unit in the system through a calculation example. Then the sensitivity analysis of the electric boiler capacity is carried out. Finally, the feasibility of the proposed model is verified through the results analysis, which provides a reference scheme for the electricity-heat integrated energy system including electric vehicles.

Document type: Article

Manage with care: the frailty of self-connections in the European airport network

Scipedia content — Fri, 12 Feb 2021 16:20:14 +0100

This study evaluates the attractiveness of self-hubbing in terms of the (a) symmetry of itineraries and the consequences for passengers in the case of missed flights. We compute the most attractive European origin-destination (O-D) pairs through self-connection and evaluate their robustness by estimating the expected delays relative to connecting times and the travel options available when a connection is missed. Results show that the potential of self-connecting markets is reduced when accounting for asymmetrical travel options and the consequences for travelers in the case of missed flights. In terms of frequencies, self-connecting passengers are, on average, found to have fewer alternatives to complete a given O-D pair than in the case of alliance-based connections (− 33%). Our findings moderate the confidence of past evidence on self-hubbing in light of the concrete reliability of self-connections for passengers. The itinerary choice made by passengers inevitably depends on the evaluation of travel quality attributes related to the (a) symmetry of the itineraries and the costs incurred through missed connections.

Document type: Article

Identifying High-Risk Intersections for Walking and Bicycling Using Multiple Data Sources in the City of San Diego

Scipedia content — Fri, 12 Feb 2021 16:19:54 +0100

Over the last decade, demand for active transportation modes such as walking and bicycling has increased. While it is desirable to provide high levels of safety for these eco-friendly modes of travel, unfortunately, the overall percentage of pedestrian and bicycle fatalities increased from 13% to 18% of total road-related fatalities in the last decade. In San Diego County, although the total number of pedestrian and bicyclist fatalities decreased over the same period of time, a similar trend with a more drastic change is observed; the overall percentage of pedestrian and bicycle fatalities increased from 19.5% to 31.8%. This study aims to estimate pedestrian and bicyclist exposure and identify signalized intersections with highest risk for walking and bicycling within the city of San Diego, California, USA. Multiple data sources such as automated pedestrian and bicycle counters, video cameras, and crash data were utilized. Data mining techniques, a new sampling strategy, and automated video processing methods were adopted to demonstrate a holistic approach that can be applied to identify facilities with highest need of improvement. Cluster analysis coupled with stratification was employed to select a representative sample of intersections for data collection. Automated pedestrian and bicycle counting models utilized in this study reached a high accuracy, provided certain conditions exist in video data. Results from exposure modeling showed that pedestrian and bicyclist volume was characterized by transportation network, population, traffic generators, and land use variables. There were both similarities and differences between pedestrian and bicycle models, including different spatial scales of influence by mode. Additionally, the study quantified risk incorporating injury severity levels, frequency of victims, distance crossed, and exposure into a single equation. It was found that not all intersections with the highest number of pedestrian and bicyclist victims were identified as high-risk after exposure and other factors such as crash severity were taken into account.

Document type: Article

A Stop-Probability Approach for O-D Service Frequency on High-Speed Railway Lines

Scipedia content — Fri, 12 Feb 2021 16:17:21 +0100

Train stop planning provides appropriate service for travel demand and stations and plays a significant role in railway operation. This paper formulates stop planning from the point of view of direct travel between origin-destination (O-D) stations and proposes an analytical method to theoretically derive optimal service frequencies for O-D demand on different levels. Considering different O-D demand characteristics and train service types, we introduce the concept of stop probability to present the mathematical formulation for stop planning with the objective of minimizing per capita travel time, which is solved by an iterative algorithm combined with local search. The resulting optimal stop probabilities can be used to calculate the required service frequency for each train type serving different demand categories. Numerical examples, based on three real-life high-speed railway lines, demonstrate the validity of the proposed method. The proposed approach provides a more flexible and practical way for stop planning that explicitly takes into account the importance of different stations and passenger travel characteristics.

Document type: Article

Experimental Study on Seismic Performance of Prefabricated Utility Tunnel

Scipedia content — Fri, 12 Feb 2021 16:14:46 +0100

Utility tunnel is a kind of underground tunnel structure that carries more than two types of public utility lines, and the utility tunnels built by the prefabricated method have been adopted in many modern cities due to their easy maintenance and environmental protection capabilities. However, knowledge about the seismic performance of the prefabricated utility tunnel and pipelines inside is quite limited. In this paper, a prefabricated utility tunnel newly built in Xi’an, China, is taken as the prototype; a series of shaking table tests are conducted to investigate the seismic performance of the prefabricated utility tunnel in loess foundation, using El Centro earthquake wave as the input loading. Details of the experimental setup focus on the design of the soil container, scaled model (1 : 10), sensor arrangement, and test cases. Dynamic responses including evaluation of boundary effect, the amplification factor of the ground and structure, distribution of soil pressure, characteristics of predominant frequencies, and the damage phenomena are analyzed. Dynamic strain obtained by Fiber Bragg Grating sensors releases the critical positions of the prefabricated utility tunnel during the earthquake. Moreover, the dynamic responses of the pipelines contained in the utility tunnel are also analyzed. From aforementioned results, the seismic performance of the prefabricated utility tunnel has been revealed. The results will provide a reference for the seismic design of prefabricated utility tunnels.

Document type: Article

Integrating in situ Measurements and City Scale Modelling to Assess the COVID–19 Lockdown Effects on Emissions and Air Quality in Athens, Greece

Scipedia content — Fri, 12 Feb 2021 16:13:52 +0100

The lockdown measures implemented worldwide to slow the spread of the COVID–19 pandemic have allowed for a unique real–world experiment, regarding the impacts of drastic emission cutbacks on urban air quality. In this study we assess the effects of a 7–week (23 March–10 May, 2020) lockdown in the Greater Area of Athens, coupling in situ observations with estimations from a meteorology–atmospheric chemistry model. Measurements in central Athens during the lockdown were compared with levels during the pre– and post–lockdown 3–week periods and with respective levels in the four previous years. We examined regulatory pollutants as well as CO"sub"2"/sub", black carbon (BC) and source–specific BC components. Models were run for pre–lockdown and lockdown periods, under baseline and reduced–emissions scenarios. The in–situ results indicate mean concentration reductions of 30–35% for traffic–related pollutants in Athens (NO"sub"2"/sub", CO, BC from fossil fuel combustion), compared to the pre–lockdown period. A large reduction (53%) was observed also for the urban CO"sub"2"/sub" enhancement while the reduction for PM"sub"2.5"/sub" was subtler (18%). Significant reductions were also observed when comparing the 2020 lockdown period with past years. However, levels rebounded immediately following the lift of the general lockdown. The decrease in measured NO"sub"2"/sub" concentrations was reproduced by the implementation of the city scale model, under a realistic reduced–emissions scenario for the lockdown period, anchored at a 46% decline of road transport activity. The model permitted the assessment of air quality improvements on a spatial scale, indicating that NO"sub"2"/sub" mean concentration reductions in areas of the Athens basin reached up to 50%. The findings suggest a potential for local traffic management strategies to reduce ambient exposure and to minimize exceedances of air quality standards for primary pollutants.

Document type: Article

Electric Vehicle Mobility-as-a-Service: Exploring the “Tri-Opt” of Novel Private Transport Business Models

Scipedia content — Fri, 12 Feb 2021 16:13:33 +0100

Three distinct trends have emerged that have disrupted the dominance of privately- owned, combustion-powered car transport in the UK. First, the electric powertrain has emerged as an affordable means of transport; the second is the development of new hire models of car ownership: third, the growth of `smart city thinking' emphasises capitalising on increased connectivity and data availability to create value. We define the combination of these three trends as the 'tri-opt' of private transport -- three disruptors that should not be considered in isolation but as interacting -- an inflection of the`Energy Trilemma'."br/"In this paper, we apply systems thinking and a mixed methodology of workshops, interviews and systems modelling to the UK city of Bristol's Smart EV Transport Hub project to identify concepts that positively combine two or more of these three `Opts'. We demonstrate that there are many synergistic overlaps and that combinations potentially create significant value. Our data highlights that of the greatest value are those use cases that the current literature base has explored the least, and can be characterised as requiring significant public and private sector collaboration.

Document type: Article

Fuzzy inference approach in traffic congestion detection

Scipedia content — Fri, 12 Feb 2021 16:12:49 +0100

One of the major tasks within the concept of an intelligent transportation system is the immediate indication of traffic breakdowns. A conventional approach evaluates a traffic condition by classif...

Document type: Article

Optimizing Vehicle Scheduling Based on Variable Timetable by Benders-and-Price Approach

Scipedia content — Fri, 12 Feb 2021 16:11:41 +0100

In practice, vehicle scheduling is planned on a variable timetable so that the departure times of trips can be shifted in tolerable ranges, rather than on a fixed timetable, to decrease the required fleet size. This paper investigates the vehicle scheduling problem on a variable timetable with the constraint that each vehicle can perform limited trips. Since the connection-based model is difficult to solve by optimization software for a medium-scale or large-scale instance, a designed path-based model is developed. A Benders-and-Price algorithm by combining the Benders decomposition and column generation is proposed to solve the LP-relaxation of the path-based model, and a bespoke Branch-and-Price is used to obtain the integer solution. Numerical experiments indicate that a variable timetable approach can reduce the required fleet size with a tolerable timetable deviation in comparison with a fixed timetable approach. Moreover, the proposed algorithm is greatly superior to GUROBI in terms of computational efficiency and guarantees the quality of the solution.

Document type: Article

Modification of Non-Metallic Inclusions in Oil-Pipeline Steels by Ca-Treatment

Scipedia content — Fri, 12 Feb 2021 16:10:50 +0100

Corrosion rate in different steel grades (including oilfield pipeline steels) is determined by the presence of non-metallic inclusions (NMI) in steels. Specifically, the effect of different inclusions on the quality of steels depends on their characteristics such as size, number, morphology, composition, and physical properties, as well as their location in the steel matrix. Therefore, the optimization and control of NMI in steels are very important today to obtain an improvement of the material properties of the final steel products. It is well known that a Ca-treatment of liquid steels in ladle before casting is an effective method for modification of non-metallic inclusions for improvement of the steel properties. Therefore, the NMI characteristics were evaluated in industrial steel samples of low carbon Ca-treated steel used for production of oil-pipelines. An electrolytic extraction technique was used for extraction of NMI from the steel samples followed by three-dimensional investigations of different inclusions and clusters by using SEM in combination with EDS. Moreover, the number and compositions of corrosion active non-metallic inclusions were estimated in hot rolled steel samples from two different heats. Finally, the corrosion resistance of these steels can be discussed depending on the characteristics of non-metallic inclusions present in the steel.

Document type: Article

A Study of Transport Behaviour of Academic Communities

Scipedia content — Fri, 12 Feb 2021 16:09:36 +0100

n important challenge to achieving sustainable university campuses is ensuring that the academic community makes sustainable transport choices. The objective of this study was to investigate the daily commuting patterns, identify the potential for change, and determine the factors and criteria affecting the transport decisions of academic communities of two universities located in Gdansk, Poland. This paper summarizes the results of trip generation measurements and a comprehensive online survey of 3678 respondents, including the universities&rsquo

staff and students. Analysis of survey results revealed clear differences between students and university staff in terms of travel patterns and factors that influence their choices. Staff usually (57%) choose the car for daily commutes with students opting for public transport (59%). The choice of travel mode in particular groups is determined mostly by car availability, trip origin location, and accessibility. The choices also depend on transport user individual requirements such as trip quality, costs, or ecology. With approximately 1400 trips daily per 1000 students, the universities are large traffic generators. Thus, how the staff and students behave determines the effect the universities have on the urban transport system. Understanding the behaviour can help to estimate whether it can be changed and how.

Document type: Article

Determining E-Bike Drivers’ Decision-Making Mechanisms during Signal Change Interval Using the Hidden Markov Driving Model

Scipedia content — Fri, 12 Feb 2021 16:07:21 +0100

Rapidly increasing e-bike use in China has resulted in new traffic problems including rising accident rates at intersections related to e-bike drivers’ decision-making during multiple signal phases. Traditional one-step decision models (such as GHM) lack randomness and cannot adequately model e-bike drivers’ complex behavior. Therefore, this study used a Hidden Markov Driving Model (HMDM) to analyze e-bike drivers’ decision-making process based on high-resolution trajectory data. Video data were collected at three intersections in Shanghai and processed for use in the HMDM model. Five decision types (pass, stop, stop-pass, pass-stop, and multiple) composed of speed and acceleration/deceleration information were defined and used to analyze the impact of flashing green signals on e-bike drivers’ behavior and decision-making processes. Approximately 40% of drivers made multiple decisions during the flashing green and yellow signal phases, in contrast to the traditional GHM model assumption that drivers only make one decision. Distance from stop-line had the most obvious influence on the number of decisions. The use of flashing green signals nearly eliminated the dilemma zone for e-bike drivers but enlarged the option zone, inducing more stop/pass decisions. HMDM can be applied to improve the accuracy of traffic simulation, the fine design of traffic signals, the stability analysis of traffic control schemes, and so on.

Document type: Article

BEACON TECHNOLOGY FOR REAL-TIME INFORMING THE TRAFFIC NETWORK USERS ABOUT THE ENVIRONMENT

Scipedia content — Fri, 12 Feb 2021 16:07:04 +0100

Informing the users about their environment is of extreme importance for their full and independent functioning in the traffic system. Today’s development of technology provides the user the access to information about their environment by using the smartphone device at any moment if there is a defined applicative solution. For this, it is necessary to define the user’s environment according to the Ambient Assisted Living (AAL) concept, which understands adequate technology of gathering, processing and distribution of information. This paper presents the proposal of the solution for informing the traffic network users about the environment for the defined group of users based on the beacon technology. The mentioned solution is based on the results of two separate studies about the needs of users who move along a part of the traffic network. The aim of the proposed solution is to provide the user with precise and real-time information and to raise the level of safety during movement.

Document type: Article

Implementation of an Energy Management Strategy with Drivability Constraints for a Dual-Motor Electric Vehicle

Scipedia content — Fri, 12 Feb 2021 16:06:34 +0100

This paper presents a real-time energy management strategy to distribute the power demand between two independent motors properly. Based on the characteristics of the novel transmission system, an enumeration-based searching approach is used to hunt for the optimal working points for both motors to maximize the overall efficiency. Like many energy management strategies, approaches that focus on reducing energy consumption can result in frequent gearshifts. To improve drivability and make a balance between energy consumption and gearshifts, a cost function is designed. To verify the effectiveness of the proposed method, a mathematical model is built, and the simulation results demonstrate the achieved improvements.

Document type: Article

Environmental Aspects of Generation Y’s Sustainable Mobility

Scipedia content — Fri, 12 Feb 2021 16:06:16 +0100

This research paper identifies and explores the opinions and attitudes of young people about urban transport. It is the first study on this topic, based on the survey, analysing the mobility choices of young adults (more specifically, Generation Y) in Poland and for countries in Central and Eastern Europe. The aim of the paper is to show their travel behaviour from sustainable mobility perspective. The primary data was obtained through the online survey. The data analysis was held with use of factor analysis and ANOVA. The research results indicated the variables influencing the environmental dimension of sustainable mobility attitudes of young adults in four areas: the ecology-oriented approach to transport, opinions about sharing economy, public car concept and future transport system. The analysis of variance revealed significant differences in the ecology-oriented approach between people born in different decades, between men and women and between people with driving licences and people without them. Those results provide the insights for local authorities and mobility service providers. The recommendations at the end of the paper focus on the need for continuation of research in similar fields.

Document type: Article

Identification of Enablers and Barriers for Public Bike Share System Adoption using Social Media and Statistical Models

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

Public bike share (PBS) systems are meant to be a sustainable urban mobility solution in areas where different travel options and the practice of active transport modes can diminish the need on the vehicle and decrease greenhouse gas emission. Although PBS systems have been included in transportation plans in the last decades experiencing an important development and growth, it is crucial to know the main enablers and barriers that PBS systems are facing to reach their goals. In this paper, first, sentiment analysis techniques are applied to user generated content (UGC) in social media comments (Facebook, Twitter and TripAdvisor) to identify these enablers and barriers. This analysis provides a set of explanatory variables that are combined with data from official statistics and the PBS observatory in Spain. As a result, a statistical model that assesses the connection between PBS use and certain characteristics of the PBS systems, utilizing sociodemographic, climate, and positive and negative opinion data extracted from social media is developed. The outcomes of the research work show that the identification of the main enablers and barriers of PBS systems can be effectively achieved following the research method and tools presented in the paper. The findings of the research can contribute to transportation planners to uncover the main factors related to the adoption and use of PBS systems, by taking advantage of publicly available data sources. Public bicycle observatory in Spain by given support.

Document type: Article

Camera-Based Blind Spot Detection with a General Purpose Lightweight Neural Network

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

Blind spot detection is an important feature of Advanced Driver Assistance Systems (ADAS). In this paper, we provide a camera-based deep learning method that accurately detects other vehicles in the blind spot, replacing the traditional higher cost solution using radars. The recent breakthrough of deep learning algorithms shows extraordinary performance when applied to many computer vision tasks. Many new convolutional neural network (CNN) structures have been proposed and most of the networks are very deep in order to achieve the state-of-art performance when evaluated with benchmarks. However, blind spot detection, as a real-time embedded system application, requires high speed processing and low computational complexity. Hereby, we propose a novel method that transfers blind spot detection to an image classification task. Subsequently, a series of experiments are conducted to design an efficient neural network by comparing some of the latest deep learning models. Furthermore, we create a dataset with more than 10,000 labeled images using the blind spot view camera mounted on a test vehicle. Finally, we train the proposed deep learning model and evaluate its performance on the dataset.

Document type: Article

Electromagnetic Energy Harvesting Technology: Key to Sustainability in Transportation Systems

Scipedia content — Fri, 12 Feb 2021 15:10:29 +0100

The convergence of concerns about environmental quality, economic vitality, social equity, and climate change have led to vast interest in the concept of sustainability. Energy harvesting from roadways is an innovative way to provide green and renewable energy for sustainable transportation. However, energy harvesting technologies are in their infancy, so limited studies were conducted to evaluate their performance. This article introduces innovative electromagnetic energy harvesting technology that includes two different mechanisms to generate electrical power: a cantilever generator mechanism and a rotational mechanism. Laboratory experimental tests were conducted to examine the performance of the two mechanisms in generating power under different simulated traffic conditions. The experimental results had approximately root mean square power 0.43 W and 0.04 W and maximum power of 2.8 W and 0.25 W for cantilever and rotational, respectively. These results showed promising capability for both mechanisms in generating power under real traffic conditions. In addition, the study revealed the potential benefits of energy harvesting from roadways to support sustainability in transportation systems. Overall, the findings show that energy harvesting can impact sustainable transportation systems significantly. However, further examination of the large-scale effects of energy harvesting from roadways on sustainability is needed.

Document type: Article

Logarithmic Mean Divisia Index Decomposition of CO2 Emissions from Urban Passenger Transport: An Empirical Study of Global Cities from 1960–2001

Scipedia content — Fri, 12 Feb 2021 15:05:41 +0100

The urban transport sector has become one of the major contributors to global CO2 emissions. This paper investigates the driving forces of changes in CO2 emissions from the passenger transport sectors in different cities, which is helpful for formulating effective carbon-reduction policies and strategies. The logarithmic mean Divisia index (LMDI) method is used to decompose the CO2 emissions changes into five driving determinants: Urbanization level, motorization level, mode structure, energy intensity, and energy mix. First, the urban transport CO2 emissions between 1960 and 2001 from 46 global cities are calculated. Then, the multiplicative decomposition results for megacities (London, New York, Paris, and Tokyo) are compared with those of other cities. Moreover, additive decomposition analyses of the 4 megacities are conducted to explore the driving forces of changes in CO2 emissions from the passenger transport sectors in these megacities between 1960 and 2001. Based on the decomposition results, some effective carbon-reduction strategies can be formulated for developing cities experiencing rapid urbanization and motorization. The main suggestions are as follows: (i) Rational land use, such as transit-oriented development, is a feasible way to control the trip distance per capita

(ii) fuel economy policies and standards formulated when there are oil crisis are effective ways to suppress the increase of CO2 emissions, and these changes should not be abandoned when oil prices fall

and (iii) cities with high population densities should focus on the development of public and non-motorized transport.

Document type: Article

The future of freight transport

Scipedia content — Fri, 12 Feb 2021 15:05:23 +0100

Document type: Article

Modeling and Simulation of Nonmotorized Vehicles’ Dispersion at Mixed Flow Intersections

Scipedia content — Fri, 12 Feb 2021 15:04:18 +0100

Interactions between motorized and nonmotorized vehicles have drawn considerable attention from researchers. They are commonly seen at mixed flow intersections where nonmotorized vehicles, without the restriction of lane markers or physical barriers, may disperse into adjacent lanes and thus lead to complex interactions with motorized vehicles. Such a dispersion phenomenon between heterogeneous participants (e-bikes and bicycles as nonmotorized vehicles versus motorized vehicles) is difficult to model. In this paper, we were inspired by the dispersion of charged particles in an electric field and modeled the dispersion phenomenon of go-straight, nonmotorized vehicles at mixed flow intersections accordingly, as it was discovered in this research that these two dispersion phenomena share three underlying commonalities with each other. A novel particle dispersion model (PDM) based on a particle’s movement in an electric field is proposed. The model is calibrated and validated using 1,490 high-definition sets of trajectory data for go-straight, nonmotorized vehicles during 43 cycles at two typical mixed flow intersections. The PDM is compared with the social force model (SFM) on their dispersion characteristics that are used to describe the nonmotorized bicycles’ behavior. The results show that the PDM performs better than the SFM with regard to depicting the dispersion characteristic indices of the nonmotorized vehicles, such as the travel time, the dispersion intensity of heterogeneous nonmotorized vehicles, the sectional dispersion degree, and other dispersion characteristics.

Document type: Article

Route Redundancy-Based Network Topology Measure of Metro Networks

Scipedia content — Fri, 12 Feb 2021 15:02:21 +0100

The metro system plays a very important role in the urban multimodal transportation system, yet it is susceptible to accidents. A well-designed metro system needs to provide alternative routes to travellers both in the disruptive events and the normal operating conditions for providing rerouting opportunities and balancing crowded lines. This paper provides a new dimension of assessing metro network performance—travellers’ route redundancy (or route diversity), which is defined as the number of behaviourally effective routes between each origin-destination (O-D) pair in the network. The route redundancy of metro network is evaluated by statistical indicators of the distribution of the O-D-level number of effective routes. Compared with the existing connectivity and accessibility measures of topology network performance, route redundancy is also based on the topology network, but it takes the travellers’ route choice into consideration. Specifically, the effective routes between each O-D pair would provide disaggregated information from the travellers’ perspective. Case studies in four metropolises in the world, i.e., Shanghai, Beijing, London, and Tokyo, are conducted to examine the predisaster preparedness of the four metro networks explicitly from the perspective of route redundancy. The results indicate that the London metro network has the best route redundancy performance in terms of the statistical indicators of the distribution of the O-D level number of effective routes. Furthermore, the results of route redundancy are compared with typical measures of topology network performance in terms of measuring connectivity and accessibility of metro networks. Their differences are attributed to the fact that the route redundancy measure considers the travellers’ O-D-level route choice beyond the pure network topology and the shortest path considerations of the existing measures. The route redundancy proposed in this paper could assist in evaluating the predisaster preparedness of current or planning metro networks from O-D level to network level.

Document type: Article

Impact of Guideline Markings on Saturation Flow Rate at Signalized Intersections

Scipedia content — Fri, 12 Feb 2021 15:02:04 +0100

Many intersections around the world are irregular crossings where the approach and exit lanes are offset or the two roads cross at oblique angles. These irregular intersections often confuse drivers and greatly affect operational efficiency. Although guideline markings are recommended in many design manuals and codes on traffic signs and markings to address these problems, the effectiveness and application conditions are ambiguous. The research goal was to analyze the impact of guideline markings on the saturation flow rate at signalized intersections. An adjustment estimation model was established based on field data collected at 33 intersections in Shanghai, China. The proposed model was validated using a before–after case study. The underlying reasons for the impact of intersection guideline markings on the saturation flow rate are discussed. The results reveal that the improvement in the saturation flow rate obtained from painting guide line markings is positively correlated with the number of traffic lanes, offset of through movement, and turning angle of left-turns. On average, improvements of 7.0% and 10.3% can be obtained for through and left-turn movements, respectively.

Document type: Article

Evaluation of the Magnetic Field Leakage from Two Wireless Power Transfer Systems for EV/PHV Driven Simultaneously

Scipedia content — Fri, 12 Feb 2021 14:58:10 +0100

Wireless power transfer for electric and plug-in hybrid vehicles has been developed to facilitate battery charging. In a wireless power transfer system, because the magnetic field leaks to the surroundings of the vehicle, it is important to evaluate the quantitative human exposure. The International Commission on Non-Ionizing Radiation Protection provides guidelines for human exposure assessment. In this study, we evaluate the magnetic field leakage under two parking configurations and current phase differences for two vehicles being simultaneously charged (3.7 kW at 85 kHz per vehicle). The results of the analysis show that the magnetic field leakage is lower than the reference level of the guidelines for all cases and that the leakage could be reduced by controlling the phase difference between the two wireless power transfer systems equally distributed from the single high-frequency power source for each parking configuration.

Document type: Article

Collaborative fleet deployment and routing for sustainable transport

Scipedia content — Fri, 12 Feb 2021 14:57:37 +0100

Efficient multi-modal transportation in the hinterland of seaport terminals dependson consolidation of container volumes in support of frequent services of high capacity means oftransport, such that sustainable multi-modal transport can compete with uni-modal road transportin cost and time. The tactical design of barge scheduled transport services involves fleet selectionand routing through the inland waterway network. The resulting network service design shouldmeet expected demand and service time requirements set by the shippers. We develop a tightMILP formulation for the Fleet Size and Mix Vehicle Routing (FSMVRP) especially adapted for thePort-Hinterland multi-modal barge network design. Also, an analytical model is developed to helpunderstand important design trade-offs made. We consider the case of horizontal cooperation of dryport container terminals that share capacity. Our results show that in case of cooperation, both costsavings and service levels are improved, and allow for sustainable multi-modal transport to becompetitive with uni-modal truck transport.

Document type: Article

Multiobjective Optimal Formulations for Bus Fleet Size of Public Transit under Headway-Based Holding Control

Scipedia content — Fri, 12 Feb 2021 14:57:01 +0100

In recent years, with the development of advanced technologies for data collection, real-time bus control strategies have been implemented to improve the daily operation of transit systems, especially headway-based holding control which is a proven strategy to reduce bus bunching and improve service reliability for high-frequency bus routes, with the concept of regulating headways between successive buses. This hot topic has inspired the reconsideration of the traditional issue of fleet size optimization and the integrated bus holding control strategy. The traditional headway-based control method only focused on the regulation of bus headways, without considering the number of buses on the route. The number of buses is usually assumed as a given in advance and the task of the control method is to regulate the headways between successive buses. They did not consider the bus fleet size problem integrated with headway-based holding control method. Therefore, this work has presented a set of optimal control formulations to minimize the costs for the passengers and the bus company through calculating the optimal number of buses and the dynamic holding time, taking into account the randomness of passenger arrivals. A set of equations were formulated to obtain the operation of the buses with headway-based holding control or the schedule-based control method. The objective was to minimize the total cost for the passengers and the bus company in the system, and a Monte Carlo simulation based solution method was subsequently designed to solve the optimization model. The effects of this optimization method were tested under different operational settings. A comparison of the total costs was conducted between the headway-based holding control and the schedule-based holding control. It was found that the model was capable of reducing the costs of the bus company and passengers through utilizing headway-based bus holding control combined with optimization of the bus fleet size. The proposed optimization model could minimize the number of buses on the route for a guaranteed service level, alleviating the problem of redundant bus fleet sizes caused by bus bunching in the traditional schedule-based control method.

Document type: Article

Analysing Stakeholder Consensus for a Sustainable Transport Development Decision by the Fuzzy AHP and Interval AHP

Scipedia content — Fri, 12 Feb 2021 14:54:58 +0100

In any public service development decision, it is essential to reach the stakeholders&rsquo

agreement to gain a sustainable result, which is accepted by all involved groups. In case this criterion is violated, the impact of the development will be less than expected due to the resistance of one group or another. Concerning public urban transport decisions, the lack of consensus might cause lower utilisation of public vehicles, thus more severe environmental damage, traffic problems and negative economic impacts. This paper aims to introduce a decision support procedure (applying the current MCDM techniques

Fuzzy and Interval AHP) which is capable of analysing and creating consensus among different stakeholder participants in a transport development problem. The combined application of FAHP and IAHP ensures that the consensus creation is not only based on an automated computation process (just as in IAHP) but also on the consideration of specific group interests. Thus, the decision makers have the liberty to express their preferences in urban planning, along with the consideration of numerical results. The procedure has been tested in a real public transport improvement decision as a follow-up project, in an emerging city, Mersin, Turkey. Results show that by the application of the proposed techniques, decision-makers can be more aware of the conflicts of interests among the involved groups, and they can pay more attention to possible violations.

Document type: Article

Rzeszow as a City Taking Steps Towards Developing Sustainable Public Transport

Scipedia content — Fri, 12 Feb 2021 14:53:47 +0100

The paper discusses problems related to the functioning of passenger transport in Rzeszow. The dynamic development of the city and the increase in the income of its inhabitants have led to significantly increased traffic within the city, which is detrimental both to the environment and the city&rsquo

s inhabitants. It limits the quality of life in the city and in the end generates additional costs for businesses and people in urban areas due to the congestion. In compliance with the policies of the European Union, this harmful tendency needs to be limited. Developing sustainable transportation should largely contribute to this objective. With the city of Rzeszow as example, this article discusses selected actions and measures taken as part of the development of sustainable transportation and demonstrates changes in the functioning of public transport based on the author&rsquo

s own research as well as data provided by the city&rsquo

s authorities. The analyses show that the actions taken so far have had a positive impact.

Document type: Article

Determining the Rational Motion Intensity of Train Traffic Flows on the Railway Corridors with Account for Balance of Expenses on Traction Resources and Cargo Owners

Scipedia content — Fri, 12 Feb 2021 14:46:18 +0100

"jats:p"The article proposes a method for determining the rational motion intensity of specific train traffic flows on railway transport corridors with account for balance of expenses on traction resources and cargo owners. A mathematical model based on stochastic optimization is developed, which allows to optimize, in the conditions of risks, the interval between trailing trains on the railway lines taking into account the limited resources of the traction rolling stock, the capacity of the stations and freight fronts at the cargo destination point. Solving this mathematical model allows to find a balance between the expenses for movement of train traffic flows from different railway lines to their terminal reference station and the expenses of a consignee, subject to the limitations of the technological logistics chain in cargo transportation. For the solution of this mathematical model, a Real-coded Genetic Algorithm (RGA) was used.

Document type: Article

Effects of on-Board Unit on Driving Behavior in Connected Vehicle Traffic Flow

Scipedia content — Fri, 12 Feb 2021 14:45:00 +0100

Connected vehicle technology has potentials to increase traffic safety, reduce traffic pollution, and ease traffic congestion. In the connected vehicle environment, the information interaction among people, cars, roads, and the environment is significantly enhanced, and driver behavior will change accordingly due to increased external stimulation. This paper designed a Vehicle-to-Vehicle (V2V) on-board unit (OBU) based on driving demand. In addition, a simulation platform for the interconnection and communication between the OBU and simulator was built. Thirty-one test drivers were investigated to drive an instrumented vehicle in four scenarios, with and without the OBU under two different traffic states. Collected trajectory data of the subject vehicle and the vehicle in front, as well as sociodemographic characteristics of the test drivers were used to evaluate the potential impact of such OBUs on driving behavior and traffic safety. Car-following behavior is an essential component of microsimulation models. This paper also investigated the impacts of the V2V OBU on car-following behaviors. Considering the car-following related indicators, the k-Means algorithm was used to categorize different car-following modes. The results show that the OBU has a positive impact on drivers in terms of speed, front distance, and the time to stable regime. Furthermore, drivers’ opinions show that the system is acceptable and useful in general.

Document type: Article

‘Rationality’ in Collective Escape Behaviour: Identifying Reference Points of Measurement at Micro and Macro Levels

Scipedia content — Fri, 12 Feb 2021 14:42:28 +0100

italic"Background"/jats:italic". Evacuation behaviour of human crowds is often characterised by the notion of ‘irrational behaviour’. While the term has been frequently used in the literature, clear definitions and methods for measuring rationality do not exist."jats:italic" Objective"/jats:italic". Here, we suggest that rationality, in this context, can alternatively and more effectively be formulated as a question of ‘optimal behaviour’. Decision optimality can potentially be measured and quantified. The main challenges, however, include (i) distinctly identifying the level at which we measure optimality, and (ii) identifying proper reference points at each level."jats:italic" Methods"/jats:italic". We differentiate between optimality at the individual (i.e., micro) and the system (i.e., macro/aggregate) levels and illustrate how certain reference points can be established at each level. We suggest that, at the micro level, optimality of individual decisions can be quantified by comparing the outcome of each individual’s decision to those of their ‘nearly equal peers’. At the macro level, optimality can be measured by simulating the system using parametric numerical models and measuring the system performance while altering the behavioural parameters compared to their empirical estimates."jats:italic" Results"/jats:italic". Having applied these methods, we observed that variation in micro level decision optimality rises rapidly as the space becomes more heavily crowded. As crowdedness increases in the environment, the difference between ‘good’ and ‘bad’ decisions becomes more distinct; and suboptimal decisions become more frequent. In other words, optimality at individual level seems to be moderated by the level of crowdedness. At the macro level, numerical simulations showed that, for certain exit attributes (like exit congestion), extreme marginal valuations (or preferences) were optimal, whereas for certain other attributes (like exit visibility), intermediate levels of valuation were closer to the optimal. In most cases, the natural observed (or estimated) tendency of evacuees (at the aggregate level) was not quite at the optimum level, meaning that the system could improve by modifying individuals’ marginal valuations of exit attributes."jats:italic" Applications and Recommendations"/jats:italic". These results highlight the importance of guiding evacuation decisions particularly in heavily crowded spaces. They also theoretically illustrate the potential benefit of influencing/modifying people’s evacuation strategies, so they make decisions that are collectively more efficient. A crucial step to this end, however, is to identify what optimum strategy is and under what circumstances people are likelier to make suboptimal decisions.

Document type: Article

The Energy-Efficient Dynamic Route Planning for Electric Vehicles

Scipedia content — Fri, 12 Feb 2021 14:41:36 +0100

Aiming to provide an approach for finding energy-efficient routes in dynamic and stochastic transportation networks for electric vehicles, this paper addresses the route planning problem in dynamic transportation network where the link travel times are assumed to be random variables to minimize total energy consumption and travel time. The changeable signals are introduced to establish state-space-time network to describe the realistic dynamic traffic network and also used to adjust the travel time according to the signal information (signal cycle, green time, and red time). By adjusting the travel time, the electric vehicle can achieve a nonstop driving mode during the traveling. Further, the nonstop driving mode could avoid frequent acceleration and deceleration at the signal intersections so as to reduce the energy consumption. Therefore, the dynamically adjusted travel time can save the energy and eliminate the waiting time. A multiobjective 0-1 integer programming model is formulated to find the optimal routes. Two methods are presented to transform the multiobjective optimization problem into a single objective problem. To verify the validity of the model, a specific simulation is conducted on a test network. The results indicate that the shortest travel time and the energy consumption of the planning route can be significantly reduced, demonstrating the effectiveness of the proposed approaches.

Document type: Article

Discrete Train Speed Profile Optimization for Urban Rail Transit: A Data-Driven Model and Integrated Algorithms Based on Machine Learning

Scipedia content — Fri, 12 Feb 2021 14:37:10 +0100

Energy-efficient train speed profile optimization problem in urban rail transit systems has attracted much attention in recent years because of the requirement of reducing operation cost and protecting the environment. Traditional methods on this problem mainly focused on formulating kinematical equations to derive the speed profile and calculate the energy consumption, which caused the possible errors due to some assumptions used in the empirical equations. To fill this gap, according to the actual speed and energy data collected from the real-world urban rail system, this paper proposes a data-driven model and integrated heuristic algorithm based on machine learning to determine the optimal speed profile with minimum energy consumption. Firstly, a data-driven optimization model (DDOM) is proposed to describe the relationship between energy consumption and discrete speed profile processed from actual data. Then, two typical machine learning algorithms, random forest regression (RFR) algorithm and support vector machine regression (SVR) algorithm, are used to identify the importance degree of velocity in the different positions of profile and calculate the traction energy consumption. Results show that the calculation average error is less than 0.1 kwh, and the energy consumption can be reduced by about 2.84% in a case study of Beijing Changping Line.

Document type: Article

Exploration of Sustainable Urban Transportation Development in China through the Forecast of Private Vehicle Ownership

Scipedia content — Fri, 12 Feb 2021 14:35:58 +0100

With the acceleration of China&rsquo

s urbanization process, the urban transportation problem has become increasingly serious. The rapid expansion of private vehicle ownership, in particular, has become one of the barriers to the realization of sustainable urban transition. This paper applied the Gompertz model to analyze the non-linear relationship between private vehicle ownership and per capita GDP in China using provincial data. In addition, we forecasted private vehicle ownership for 31 Chinese provinces for the period of 2019&ndash

2030 and predicted the time to reach the upper limit of 1000 people vehicle ownership of each province according to different scenarios. The main findings revealed that the number of private vehicles owned in China&rsquo

s provinces was in line with &ldquo

S&rdquo

-shaped development and was currently in the process of accelerated growth. Under the scenario of an annual per capita GDP growth rate of 6%, China&rsquo

s private vehicle ownership will reach 246 million, 375 million, and 475 million in 2020, 2025, and 2030, respectively. This indicates that China&rsquo

s expansion of private vehicle ownership will generate significant challenges, such as on-road vehicle-related fossil fuel consumption, pollutant emissions, traffic congestion, and scrapped vehicle recycling. These issues will become increasingly prominent. In provinces such as Hubei, Hebei, Hunan, and other central provinces that have a 50&ndash

60% urbanization rate, the large potential for income promotion will significantly stimulate the increase in private vehicle ownership, and the upper limit of 1000 people vehicle ownership in each province will be reached in 2032, 2037, and 2046 with annual per capita GDP growth rates of 8%, 6%, and 4%, respectively.

Document type: Article

Capacity Evaluation of a Railway Terminal Using Microsimulation: Case Study of a Freight Village in Turin

Scipedia content — Fri, 12 Feb 2021 14:33:03 +0100

Increasingly significant freight transport had led to larger and more complex transport chains. More specifically, intermodal transport has arisen as a desirable alternative to long-haul road transport, as it creates opportunities for cost reduction and to decrease both polluting emissions and road congestion. Hence, achieving good levels of service in intermodal dedicated structures is of paramount importance for the success of this transport option. The global objective of this research is to determine the capacity of the Freight Village of Turin. This is motivated by future changes in traffic demand, related with the neighboring Port of Savona-Vado. The role of freight villages and other logistics centers is becoming progressively more substantial with saturating sea ports focusing on handling operations. Existing literature shows success in intermodal transport highly depends on terminal performance. To fulfil the already mentioned objective, a simulation model was developed, based on discrete-event methodology, which simulates rail and handling operation inside the freight village. The model is then used to test several scenarios with the purpose of investigating variation in operation techniques and resources and the respective impact it has on comprehensive capacity. Confronting the tested scenarios allowed to comprehend the inefficiencies of both rail and handling processes, hence concluding that locomotive operation presents the most limiting factor. Furthermore, by combining different operation conditions and resources, it was possible to conclude how these affect final capacity and overall performance.

Document type: Article

Application Design Aiming to Minimize Drivers’ Trip Duration through Intermediate Charging at Public Station Deployed in Smart Cities

Scipedia content — Fri, 12 Feb 2021 14:32:31 +0100

Today, smart cities are turning to electric transport, carpooling and zero emission zones. The growing number of electric vehicles on the roads makes it increasingly necessary to have a public charging infrastructure. On the other hand, the main limitations of electric vehicles are the limited range of their batteries and their relatively long charging times. To avoid having problems to recharge, electric vehicle drivers must plan their journeys more thoroughly than others. At the goal of optimizing trip time, drivers need to automate their travel plans based on a smart charging solution, which will require the development of new Vehicle-to-Grid applications that will allow at the charging stations to dynamically interact with the vehicles. In this paper, we propose an architecture based on an algorithm allowing the management of charging plans for electric vehicles traveling on the road to their destination, in order to minimize the duration of the drivers&rsquo

journey including waiting and charging times. The decision taken by the algorithm based on the exploration of the data of each public supply station according to its location, number of vehicles in the queue, number of charging sockets, and rates of service.

Document type: Article