Scipedia: Documents published in 2019

An extended conceptualization of the relationship between the built environment and travel behavior

Scipedia content — Fri, 12 Feb 2021 14:32:15 +0100

Despite a large body of research suggesting that the built environment influences individual travel behavior, uncertainty remains about the true nature, size, and strength of any causal relationships between the built environment and travel behavior. Residential self-selection, the phenomenon whereby individuals or households select a residential area based on their transport attitudes, is a frequently proposed alternative explanation for the reported associations. To resolve the issue of residential self-selection, longitudinal studies are often recommended. In this paper, we argue that intervention study designs are insufficient to fully resolve the problem and that intervention studies on the built environment and travel behavior may still be biased by residential selfselection. The aim of this paper is to extend existing conceptualizations of the relationships between the built environment, travel behavior, and attitudes and to provide suggestions for how a causal relationship between the built environment and travel behavior may be ascertained with more accurate estimates of effect sizes. We discuss the complexities of determining causal effects in intervention studies with participants who relocate, and the biases that may occur. We illustrate the complexities by presenting extended conceptualizations. Based on these conceptualizations, we provide considerations for future research. We suggest repeating analyses with and without individuals who relocated during the study, and with and without statistical controls for residential relocation. Additional quantitative and qualitative analyses will be necessary to obtain more accurate effect size estimates and a better understanding of the causal relationships. JP and DO were supported by the Medical Research Council [Unit Program number MC_UP_12015/6]. The Commuting and Health in Cambridge study was developed by David Ogilvie, Simon Griffin, Andy Jones and Roger Mackett and initially funded under the auspices of the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence. Funding from the British Heart Foundation, Economic and Social Research Council, Medical Research Council, National Institute for Health Research and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. The study was subsequently funded by the National Institute for Health Research Public Health Research program.

Document type: Article

Machine Learning in Transportation

Scipedia content — Fri, 12 Feb 2021 14:30:50 +0100

Document type: Article

The Benefits of Randomly Delayed Charging of Electric Vehicles

Scipedia content — Fri, 12 Feb 2021 14:30:35 +0100

The increasing use of electric vehicles, combined with the trend of higher charging currents, puts a significant strain on the electrical grid. Many solutions to this problem are being discussed, some relying on some form of smart grid, others proposing stricter regulations concerning charging electric vehicles. In this study, a different approach, called randomly delayed charging, is explored. The main idea is to charge a battery over night, but instead of starting the charging process as soon as possible, introduce a random delay, satisfying the boundary condition that the battery is sufficiently charged in the morning. Benefits of this technique are investigated by using an agent-based simulation that simulates commuters and calculates the electricity demand with temporal resolution. Results suggest that randomly delayed charging can have a significant effect on peak load caused by charging and that this benefit increases the higher the used charging current is. Randomly delayed charging can be a viable option for reducing the peak electricity demand that is caused by charging electric vehicles.

Document type: Article

Modelling of Noise Pollution Due to Heterogeneous Highway Traffic in India

Scipedia content — Fri, 12 Feb 2021 14:21:59 +0100

"jats:p"Compared to homogeneous traffic flow, traffic speed variation is drastic with the involvement of heterogeneity. With an intent of studying the negative upshot of fluctuating speeds of heterogeneous traffic on the environment, the current paper is the outcome of the research done on various highways located in the states of Andhra Pradesh and Telangana in India, with an objective of developing a comprehensive noise prediction model by taking into account the traffic and roadway factors. Quantified noise levels [Leq (dBA) and L10 (dBA)] revealed that for the traffic speed variation of 10 to 95 kmph, the traffic noise levels were significantly affected by the variations in the proportion of the vehicle. On a specific note, the proposed model can be effectively used for the highway traffic noise prediction especially for the heterogeneous traffic, as the difference between the measured and predicted noise levels are within 1 to 10 dB (A).

Document type: Article

Model of nuclear energy valuation in the context of e-mobility

Scipedia content — Fri, 12 Feb 2021 14:20:59 +0100

"jats:p"Due to the depletion of fossil fuels and the degradation of the ecological balance, the transition of mobility to new ways of propelling means of transportation is one of the toughest themes of sustainability, debated as such and by scientific research. At the same time technological research has already proposed several forms of vehicle powering and the manufacturers have even offered the market a significant number of electrically propelled vehicles - the option with the greatest technical and economic potential for everything that will mean future transportation of people and freight. Unfortunately, the development of electrical mobility to its quasi-state is dependent on increasing the capacity of supplying enough electricity from the power industry. The objective of our study is to develop a model for the utilization of nuclear energy in view of the global expansion of e-mobility applications. In the context of increased demand for electricity - due to new e-mobility technologies and applications, nuclear power can become the most efficient and constant form of electricity generation. The research methodology is based on qualitative analyzes of new e-mobility applications and their diversification tendencies, but also on quantitative analysis based on a specialized questionnaire. The novelty of the research finds its exemplification in attempts to explain the importance of nuclear energy in the new context of climate change and at the same time proposing a hypothesis regarding the possible maintenance and / or refurbishment of nuclear power plants.

Document type: Article

An Analysis of Habitual Mode Use in the Years of Rising Oil Prices

Scipedia content — Fri, 12 Feb 2021 14:20:24 +0100

The existence of state dependence derived from panel data has played a very important role in studying employment and labor policies. This study is about state dependence of the transportation sector using retrospective panel survey data. The Ministry of Land, Infrastructure and Transport of Korea has conducted the survey to monitor changes in vehicle ownership and usage nationwide and to prepare measures when oil prices tend to rise sharply. From this data, we identify the existence of state dependence on passenger cars, public transportation, and nonmotorized modes. To do this, we estimate and analyze the dynamic random effects probit model that explains the selection of each transportation mode after controlling for the unobserved individual heterogeneity. Our results indicate that despite the rise of oil prices, behavior of habitual use (i.e., state dependence) of transportation modes is found in all three modes. The amount of state dependence of nonmotorized modes was the largest, followed by passenger cars and public transportation. From the estimated models, important policy implications can be drawn from the fact that the presence of state dependence and the importance of early habit formation are important not only in nonmotorized modes but also in public transportation. In other words, if policy makers want to encourage people to use public transportation in a new city, it suggests that a sufficient and convenient public transportation network should be built before people move to the city. Once cities are built without sufficient public transportation networks and people have become accustomed to using private cars, then it will be more difficult to change their transportation modes, requiring much more social efforts and costs.

Document type: Article

Cycling at Intersections: a multi-objective assessement for traffic, emissions and safety

Scipedia content — Fri, 12 Feb 2021 14:17:39 +0100

This paper evaluated in an integrated manner the traffic performance, pollutant emissions and road conflicts between bicycles and motor vehicles at a signalized intersection. Two alternative scenarios were examined: (i) Bicycles increment and motor vehicles replacement within the cycle-fixed traffic signal; (ii) Replacing the existing traffic control by a conventional two-lane roundabout and evaluating the impacts of bicycles increment. For each scenario, bicycle demand was varied from 9 to 270 bicycles per hour. Traffic flow and vehicle dynamic data were collected from a three-leg signalized intersection in Aveiro, Portugal. The microscopic traffic model (VISSIM) paired with an emission (Vehicle Specific Power – VSP) methodology and safety (Surrogate Safety Assessment Methodology – SSAM) model were used to assess intersection-specific operations. The Fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was used to find the optimal bicycle demands. The results showed that two-lane roundabout outperformed the existing traffic control, namely in highest bicycle demand scenario (number of stops and travel time reduced in 78% and 14%, respectively; CO2, NOX, and HC decreased 9%, 7%, and 12%, respectively). It was also found that the number of conflicts was significantly reduced (-49%) with this latter layout even in maximum bicycle demand scenario (270 bicycles per hour). However, roundabout layout lead to more severe conflicts and potential crashes. The analysis showed that bicycle demands of 75, 95 and 110 bicycles per hour delivered good environmental and safety outcomes for the intersection. published

Document type: Article

Dynamic Changes in Maritime Research Capability in Chinese Universities

Scipedia content — Fri, 12 Feb 2021 14:17:24 +0100

This study determines the top fifty authors in China and their university affiliations in the maritime transportation field, compared to their world ranking. We refer to China in the broad sense of the Chinese economies, including not only mainland China and Hong Kong, but also Chinese Taipei (Taiwan) and Singapore. This study analyzes sixty-five SSCI and SCI journals in the field of maritime and transportation between the years 2000 and 2015. In terms of ranking, three indicators are employed: total number of articles, weighted score (indication of author contribution), and the impact score. With the exception of Shanghai Jiao Tong University, no other universities selected in the first phase of Project 985, which received billions of dollars in government support/aid, were listed in the world ranking. Star authors are deemed to have contributed greatly to the rankings of their affiliated universities. The future of China’s rankings is bright in view of the increasing number of papers being published by Chinese authors and universities and their strong grounding in quantitative methodologies.

Document type: Article

Sustainability Challenges in Maritime Transport and Logistics Industry and Its Way Ahead

Scipedia content — Fri, 12 Feb 2021 14:14:29 +0100

Sustainability issues in the field of shipping, port and maritime logistics, commonly known as the maritime transport and logistics industry, have historically received less stakeholder attention as compared to aviation and overland freight sectors. However, as International Maritime Organization (IMO) regulations on ships and port/city interaction has increased since 1997, the stakeholders in the industry have gradually started paying attention to sustainability issues, across all the sectors, such as, aviation, land transport, and supply chain. As a result, the industry has accumulated a significant body of academic research outcomes over the last two decades. This Special Issue aims to examine the various themes in recent sustainability studies, particularly relating to shipping, port, and maritime logistics, and identify and discuss the key topics emerging in sustainability in the industry. It will contribute to increasing industry stakeholders’ understanding of the current situation in sustainability, assist them in the design of appropriate managerial insights and help them develop appropriate sustainability policies for the industry.

Document type: Article

Predicting response rates of all and recruited respondents: A first attempt

Scipedia content — Fri, 12 Feb 2021 14:13:38 +0100

This paper reports on the link between a well-defined measure of response burden and response rates among all (uncommitted) and pre-recruited respondents. We show within the limits of our sample of 68 survey waves (including pre-tests; resulting from 35 studies) that the response burden impact is mediated by the level of the commitment of the respondents and the presence of a monetary incentive. This is the first time that a research group provides a response rate forecasting model for its own work and for others to adopt, test and adapt.

Document type: Article

Scale-free resilience of real traffic jams

Scipedia content — Fri, 12 Feb 2021 14:13:19 +0100

The concept of resilience can be realized in natural and engineering systems, representing the ability of system to adapt and recover from various disturbances. Although resilience is a critical property needed for understanding and managing the risks and collapses of transportation system, an accepted and useful definition of resilience for urban traffic as well as its statistical property under perturbations is still missing. Here we define city traffic resilience based on the spatio-temporal clusters of congestion in real traffic, and find that the resilience follows a scale free distribution in two-dimensional city road networks and one-dimensional highways, with different exponents, but similar exponents in different days and different cities. The traffic resilience is also revealed to have a novel scaling relation between the cluster size of the spatio-temporal jam and its recovery duration, independent of microscopic details. Our findings of universal traffic resilience can provide indication towards better understanding and designing these complex engineering systems under internal and external disturbances.

Comment: 6 pages, 4 figure

Document type: Article

Automatic Longitudinal Regenerative Control of EVs Based on a Driver Characteristics-Oriented Deceleration Model

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

To preserve the fun of driving and enhance driving convenience, a smart regenerative braking system (SRS) is developed. The SRS provides automatic regeneration that is appropriate for the driving conditions, but the existing technology has a low level of acceptability and comfort. To solve this problem, this paper presents an automatic regenerative control system based on a deceleration model that reflects the driver&rsquo

s characteristics. The deceleration model is designed as a parametric model that mimics the driver&rsquo

s behavior. In addition, it consists of parameters that represent the driver&rsquo

s characteristics. These parameters are updated online by a learning algorithm. The validation results of the vehicle testing show that the vehicle maintained a safe distance from the leading car while simulating a driver&rsquo

s behavior. Of all the deceleration that occurred during the testing, 92% was conducted by the automatic regeneration system. In addition, the results of the online learning algorithm are different based on the driver&rsquo

s deceleration pattern. The presented automatic regenerative control system can be safely used in diverse car-following situations. Moreover, the system&rsquo

s acceptability is improved by updating the driver characteristics. In the future, the algorithm will be extended for use in more diverse deceleration situations by using intelligent transportation system information.

Document type: Article

Influence of the length parameter of an underground oil pipeline on the frequency of free oscillation

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

The problem of finding the natural frequencies of thin-walled underground oil pipelines is solved, based on the application of a semi-momentless theory of cylindrical shells of medium bending, in which bending moments in the longitudinal direction are not taken into account in view of their smallness compared with moments acting in the transverse direction. The solution to this approach is a fourth-order homogeneous differential equation satisfying the boundary conditions of articulation at each end. This equation includes the parameters of the length, internal pressure, thinness of the pipeline, as well as the values of the coefficient of elastic resistance of the soil, the attached mass of the soil and the attached mass of the flowing oil. Based on the data obtained by the derived formulas, the frequency characteristics of large-diameter thin-walled underground oil pipelines are determined depending on the length of the element, as well as on the soil conditions. It has been established that the minimum frequencies are realized for shell modes of vibration with a length parameter of the pipeline section (the ratio of the length of the section to the radius) not exceeding 13. A formula is derived that allows one to determine the boundary between the use of the rod and shell theory for calculating pipelines for dynamic effects. Using the dynamic stability criterion, in which the frequency of natural oscillations vanishes, expressions are derived that allow one to determine the external critical pressure on the wall of the pipeline, which takes into account the length of the pipeline, as well as the number of half waves in the transverse and longitudinal directions, in which the pipeline goes into emergency condition.

Document type: Article

Hierarchical Sarsa Learning Based Route Guidance Algorithm

Scipedia content — Fri, 12 Feb 2021 14:10:54 +0100

In modern society, route guidance problems can be found everywhere. Reinforcement learning models can be normally used to solve such kind of problems; particularly, Sarsa Learning is suitable for tackling with dynamic route guidance problem. But how to solve the large state space of digital road network is a challenge for Sarsa Learning, which is very common due to the large scale of modern road network. In this study, the hierarchical Sarsa learning based route guidance algorithm (HSLRG) is proposed to guide vehicles in the large scale road network, in which, by decomposing the route guidance task, the state space of route guidance system can be reduced. In this method, Multilevel Network method is introduced, and Differential Evolution based clustering method is adopted to optimize the multilevel road network structure. The proposed algorithm was simulated with several different scale road networks; the experiment results show that, in the large scale road networks, the proposed method can greatly enhance the efficiency of the dynamic route guidance system.

Document type: Article

Decarbonizing Maritime Transport: The Importance of Engine Technology and Regulations for LNG to serve as a Transition Fuel

Scipedia content — Fri, 12 Feb 2021 14:10:15 +0100

Current Greenhous gas emissions (GHG) from maritime transport represent around 3% of global anthropogenic GHG emissions and will have to be cut in half by 2050 to meet Paris agreement goals. Liquefied natural gas (LNG) is by many seen as a potential transition fuel for decarbonizing shipping. Its favorable hydrogen to carbon ratio compared to diesel (marine gas oil, MGO) or bunker fuel (heavy fuel oil, HFO) translates directly into lower carbon emissions per kilowatt produced. However, these gains may be nullified once one includes the higher Well-to-tank emissions (WTT) of the LNG supply chain and the vessel’s un-combusted methane slip (CH4) from its combustion engine. Previous studies have tended to focus either on greenhouse gas emissions from LNG in a Well-to-wake (WTW) perspective, or on alternative engine technologies and their impact on the vessel’s Tank-to-wake emissions (TTW). This study investigates under what conditions LNG can serve as a transition fuel in the decarbonization of maritime transport, while ensuring the lowest possible additional global warming impact. Transition refers to the process of moving away from fossil fuels towards new and low carbon fuels and engine technologies. Our results show: First, the importance of applying appropriate engine technologies to maximize GHG reductions; Second, that applying best engine technologies is not economically profitable; Third, how regulations could be amended to reward best engine technologies. Importantly, while the GHG reduction of LNG even with best engine technology (dual fuel diesel engine) are limited, ships with these engines can with economically modest modification switch to ammonia produced with renewable energy when it becomes available in sufficient amounts. This study has been financially supported by the Norwegian Research Council project (Norges Forskningsråd) SFI Smart Maritime project number 237917.

Document type: Article

A Conceptualized Hydrail Powertrain: A Case Study of the Union Pearson Express Route

Scipedia content — Fri, 12 Feb 2021 14:05:36 +0100

hydrogen rail (hydrail) powertrain is conceptualized in this study, using drive cycles collected from the trains currently working on the Union Pearson Express (UPE) railroad. The powertrain consists of three preliminary different subsystems: fuel cell, battery, and hydrogen storage systems. A backward design approach is proposed to calculate the time-variable power demand based on a &ldquo

route simulation data&rdquo

method. The powertrain components are then conceptually sized according to the calculated duty cycle. The results of this study show that 275 kg of hydrogen is sufficient to satisfy the daily power and energy demand of a hydrogen locomotive with drive cycles similar to the ones currently working on the UPE rail route.

Document type: Article

Access or Accessibility? A Critique of the Urban Transport SDG Indicator

Scipedia content — Fri, 12 Feb 2021 14:04:01 +0100

Progress towards the UN Sustainable Development Goals (SDGs) is being evaluated through the use of indicators. Despite the importance of these indicators, the academic community has done little in terms of a critical reflection on their choice, relevance, framing and operationalization. This holds for many SDG domains, also for the urban sector domain of target 11. To partially address this void, we aim to critically review the UN methodology for the urban access indicator, SDG indicator 11.2. In discussing its conceptual framing against the background of paradigm shifts in transportation planning, we argue that this indicator has a number of shortcomings. The most important one is that it is supply oriented and measures access to transportation infrastructure, rather than accessibility to activity locations. As an alternative, we develop two accessibility indicators that show substantial variation in accessibility across geographical areas. We implement all indicators for the city of Bogotá

in Colombia, using a geo-information based approach. Our results show that SDG indicator 11.2 fails to represent the transport reality well. Its supply oriented focus neglects transport demand, oversimplifies the transport system and hides existing inequalities. Moreover, it does not provide useful evidence for targeting new interventions. The proposed accessibility indicators provide a more diverse, complete and realistic picture of the performance of the transport system. These indicators also capture the large spatial and socio-economic inequalities and can help to target improvements in urban transportation.

Document type: Article

Bus and train connections between towns in Lower Silesia under different operational models:Competition or complementarity?

Scipedia content — Fri, 12 Feb 2021 13:59:28 +0100

"jats:p"Relationships between the activities of bus carriers and rail passenger traffic (and the railway offer) are examined in this article. The study was carried out in peripheral areas located at the Polish and Czech borderlands in Lower Silesia province. High quality rail transport generally increases the demand for transport services. Therefore, the proper development of transport offer plays a key role in the functioning of public transport systems, the backbone of which is rail transport. The study also shows that under conditions of transport market deregulation, bus carriers have developed a competitive network which is not complementary to rail transport. As a consequence, the deregulation of the transport market has increased the risk of transport exclusion.

Document type: Article

Community Detection in Airline Networks: An Empirical Analysis of American vs. Southwest Airlines

Scipedia content — Fri, 12 Feb 2021 13:59:08 +0100

In this paper, we develop a route-traffic-based method for detecting community structures in airline networks. Our model is both an application and an extension of the Clauset-Newman-Moore (CNM) modularity maximization algorithm, in that we apply the CNM algorithm to large airline networks, and take both route distance and passenger volumes into account. Therefore, the relationships between airports are defined not only based on the topological structure of the network but also by a traffic-driven indicator. To illustrate our model, two case studies are presented: American Airlines and Southwest Airlines. Results show that the model is effective in exploring the characteristics of the network connections, including the detection of the most influential nodes and communities on the formation of different network structures. This information is important from an airline operation pattern perspective to identify the vulnerability of networks.

Document type: Article

Holographic Mixed Reality System for Air Traffic Control and Management

Scipedia content — Fri, 12 Feb 2021 13:57:32 +0100

Based on a long-term prediction by the International Civil Aviation Organization indicating steady increases in air traffic demand throughout the world, the workloads of air traffic controllers are expected to continuously increase. Air traffic control and management (ATC/M) includes the processing of various unstructured composite data along with the real-time visualization of aircraft data. To prepare for future air traffic, research and development intended to effectively present various complex navigation data to air traffic controllers is necessary. This paper presents a mixed reality-based air traffic control system for the improvement of and support for air traffic controllers&rsquo

workflow using mixed reality technology that is effective for the delivery of information such as complex navigation data. The existing control systems involve difficulties in information access and interpretation. Therefore, taking notice of the necessity for the integration of air traffic control systems, this study presents the mixed reality (MR) system, which is a new approach, that enables the control of air traffic in interactive environments. This system is provided in a form usable in actual operational environments with a head-mounted see-through display installed with a controller to enable more structured work support. In addition, since this system can be controlled first-hand by air traffic controllers, it provides a new experience through improved work efficiency and productivity.

Document type: Article

Energy Effectiveness of Jet Fuel Utilization in Brazilian Air Transport

Scipedia content — Fri, 12 Feb 2021 13:55:11 +0100

Since World War I, the commercial aviation industry has seen many improvements that now allow people and goods to reach the other side of the world in a few hours, consuming much less fuel than in recent decades. Improvements in cargo capacity and energy efficiency were significant, and in this scenario, commercial airlines were able to thrive and bring great benefits to the world economy. However, this sector is facing environmental challenges due to the intensive use of jet fuel. Brazil is one of the largest domestic air passenger markets in the world and still has great growth potential, considering its economic potential and territorial dimensions, which are roughly the same size as the US and twice the size of the European Union. This paper discusses the partial productivity of jet fuel in Brazilian domestic aviation and proposes an econometric method to support public regulators and airline decisions. The proposed model uses variables, such as aircraft size, route characteristics, and idle flight capacity, in a panel data analysis. The results show that reducing idle capacity is one of the best ways to achieve better short-term fuel efficiency, and therefore will reduce the environmental impacts and have positive economic effects on commercial air transport activities. This paper brings a new approach to the discussion of airline performance, focusing on the use of jet fuel, with economic and environmental consequences.

Document type: Article

Solution to Shortest Path Problem Using a Connective Probe Machine

Scipedia content — Fri, 12 Feb 2021 13:50:20 +0100

With the continuous urban scale expansion, traffic networks have become extremely complex. Finding an optimal route in the shortest time has become a difficult and important issue in traffic engineering study. In this study, a novel computing model, namely, probe machine, is used to solve this problem. Similar to previous studies, urban transport networks can be abstracted into maps, in which points representing places of origin, destinations, and other buildings constitute the data library and edges representing the road make up the probe library. The true solution can be obtained after one probe operation on the computing platform. And by comparing the solving process with Dijkstra’s and Floyd’s algorithms, the computing efficiency of the probe machine is clearly superior, although all three methods can solve the shortest path problem and obtain the same solution.

Document type: Article

Transparency and Application of IAS 20 by the European Air Navigation Services Providers

Scipedia content — Fri, 12 Feb 2021 13:49:06 +0100

The Air Navigation Service Providers (ANSP) are monopolistic companies, subject to regulation. The EU regulation 550/2004 requires that ANSP shall comply with the international accounting standards. The majority of European ANSPs draws the grants of the SESAR project. IAS 20 sets the rules for accounting for government grants. The subject of this article is transparency, obeying the rules of the EU Regulation 550/2004 and publishing the information according to IAS 20 in the years 2015-2017, when the ANSPs drew significant amounts from the government grants. The aim of the article is to research how the requirements of transparency of both legal documents are obeyed, with special regard to impact of grants to price setting of ANSPs. The annual reports of 17 ANSPs, members of A6 alliance were subject of this research. The outcomes of the research are that these rules are obeyed in quite a low extent, that the form and content of the annual reports are very diverse and thus the effects of the regulations, stemming from the programme Single European Sky is low.

Document type: Article

Equilibrium between Road Traffic Congestion and Low-Carbon Economy: A Case Study from Beijing, China

Scipedia content — Fri, 12 Feb 2021 13:48:49 +0100

China has allocated low-carbon targets into all regions and trades, and road traffic also has its own emission reduction targets. Congestion may increase carbon emissions from road traffic. It is worthwhile to study whether it is possible to achieve the goal of road traffic reduction by controlling congestion

that is, to achieve the equilibrium between traffic congestion and a low-carbon economy. The innovation of this paper is mainly reflected in the innovative topic selection, the introduction of a traffic index, and the establishment of the first traffic congestion and low-carbon economic equilibrium model. First, the relevant calculation method of the traffic index is introduced, and the traffic index is used to quantify the traffic congestion degree. Using the traffic index, GDP, and road passenger traffic volume, a nonlinear regression model of road traffic carbon emissions is constructed. Then, the calculation method of the carbon emission intensity of road traffic in the region is proposed. The equilibrium model of traffic congestion and a low-carbon economy is constructed to look for the degree of road traffic congestion that may occur under the permitted carbon emission intensity. Taking Beijing, where electric vehicles account for less than 3% of the total vehicles, as an example, it is difficult to achieve the equilibrium target between road traffic congestion and a low-carbon economy by alleviating traffic congestion in 2020. If the target of traffic carbon emission reduction in 2020 is adjusted from 40%&ndash

45% to 19.7% based on 2005, the equilibrium will be achieved. A negative correlation between road traffic carbon emissions and the reciprocal of the traffic index (1/TI) is found after eliminating the effects of GDP and PTV (road passenger traffic volume). As the traffic index decreases by units, the carbon emission reduction accelerates. The results show that carbon reduction targets cannot be simply allocated to various industries. The results of the research on the degree of the impact of traffic congestion on carbon emissions can be used as a basis for carbon reduction decisions of the traffic sector. The research method of this paper can provide a reference for the study of the equilibrium of traffic congestion and a low-carbon economy in other regions.

Document type: Article

Neural Network-Based Modeling of Electric Vehicle Energy Demand and All Electric Range

Scipedia content — Fri, 12 Feb 2021 13:48:32 +0100

A deep neural network-based approach of energy demand modeling of electric vehicles (EV) is proposed in this paper. The model-based prediction of energy demand is based on driving cycle time series used as a model input, which is properly preprocessed and transformed into 1D or 2D static maps to serve as a static input to the neural network. Several deep feedforward neural network architectures are considered for this application along with different model input formats. Two energy demand models are derived, where the first one predicts the battery state-of-charge and fuel consumption at destination for an extended range electric vehicle, and the second one predicts the vehicle all-electric range. The models are validated based on a separate test dataset when compared to the one used in neural network training, and they are compared with the traditional response surface approach to illustrate effectiveness of the method proposed.

Document type: Article

Traffic lights synchronization for Bus Rapid Transit using a parallel evolutionary algorithm

Scipedia content — Fri, 12 Feb 2021 13:46:22 +0100

This article presents a parallel evolutionary algorithm for public transport optimization by synchronizing traffic lights in the context of Bus Rapid Transit systems. The related optimization problem is NP-hard, so exact computational methods are not useful to solve real-world instances. Our research introduces a parallel evolutionary algorithm to efficiently configure and synchronize traffic lights and improve the average speed of buses and other vehicles. The Bus Rapid Transit on Garzón Avenue (Montevideo, Uruguay) is used as a case study. This is an interesting complex urban scenario due to the number of crossings, streets, and traffic lights in the zone. The experimental analysis compares the numerical results computed by the parallel evolutionary algorithm with a scenario that models the current reality. The results show that the proposed evolutionary algorithm achieves better quality of service when compared with the current reality, improving up to 15.3% the average bus speed and 24.8% the average speed of other vehicles. A multiobjective optimization analysis also demonstrates that additional improvements can be achieved by assigning different priorities to buses and other vehicles. In addition, further improvements can be achieved on a modified scenario simply by deleting a few bus stops and changing some traffic lights rules. The benefits of using a parallel solver are also highlighted, as the parallel version is able to accelerate the execution times up to 26.9× when compared with the sequential version. Keywords: Bus Rapid Transit, Traffic lights synchronization, Evolutionary algorithm

Document type: Article

Optimizing Transportation Network of Recovering End-of-Life Vehicles by Compromising Program in Polymorphic Uncertain Environment

Scipedia content — Fri, 12 Feb 2021 13:44:48 +0100

With rapid development of technology and improvement of living standards, the per capita holding of automobiles greatly increases, and the amount of end-of-life vehicles (ELVs) becomes larger and larger such that it is valuable to investigate an effective strategy for recycling ELVs from the viewpoints of environmental protection and resource utilization. In this paper, an optimization model with fuzzy and stochastic parameters is built to formulate the transportation planning problems of recycling ELVs in polymorphic uncertain environment, where the unit processing and transportation costs, the selling price of reused items, and the fixed cost are all fuzzy, while the demand in secondary market and the production capacity are random owing to features underlying the practical data. For this complicated polymorphic uncertain optimization model, a unified compromising approach is proposed to hedge the uncertainty of this model such that some powerful optimization algorithms can be applied to make an optimal recycling plan. Then, an interactive algorithm is developed to find a compromising solution of the uncertain model. Numerical results show efficiency of the algorithm and a number of important managerial insights are revealed from the proposed model by scenario analysis and sensitivity analysis.

Document type: Article

IRODS metadata management for a cancer genome analysis workflow

Scipedia content — Fri, 12 Feb 2021 13:44:28 +0100

Background: The massive amounts of data from next generation sequencing (NGS) methods pose various challenges with respect to data security, storage and metadata management. While there is a broad range of data analysis pipelines, these challenges remain largely unaddressed to date. Results: We describe the integration of the open-source metadata management system iRODS (Integrated Rule-Oriented Data System) with a cancer genome analysis pipeline in a high performance computing environment. The system allows for customized metadata attributes as well as fine-grained protection rules and is augmented by a user-friendly front-end for metadata input. This results in a robust, efficient end-to-end workflow under consideration of data security, central storage and unified metadata information. Conclusions: Integrating iRODS with an NGS data analysis pipeline is a suitable method for addressing the challenges of data security, storage and metadata management in NGS environments.

Document type: Article

Occurrence and Characterization of Paraffin Wax Formed in Developing Wells and Pipelines

Scipedia content — Fri, 12 Feb 2021 13:40:55 +0100

Deposition and precipitation of paraffin wax in pipelines are major problems in the production, transfer, storage, and processing of crude oil. To prevent complete clogging, it is necessary to minimize and remove deposited wax in pipelines and tubing. Significant research has been done addressing the mechanisms of wax formation and its composition. In this review, the status of research and perspectives on the occurrence and characterization of the paraffin wax that forms in crude oil developing wells and pipelines has been critically reviewed. Several approaches for detecting paraffin wax and managing wax formation damage during oil recovery were discussed. This review also highlighted the effects of temperature and crude oil type on wax formation.

Document type: Article

Switched reluctance motor design for electric vehicles based on harmonics and back EMF analysis

Scipedia content — Fri, 12 Feb 2021 13:38:49 +0100

Permanent magnet synchronous motors are widely accepted in automotive applications. The high torque density, high rotational speed with maximum efficiency in electric vehicle applications is technically challenging for motor design. However, these machines are expensive and difficult to work at high-temperature harsh environment due to permanent magnets demagnetisation features. Alternatively, switched reluctance motors can provide similar output characteristics and a wider speed. Thus these are considered to be more fault tolerant and more reliable. This study proposes a 20 kW, three-phase switched reluctance motor and analyse its overall performance and harmonic contents. The study is conducted by optimising the slot filling factor, excitation voltage and switching sequence of an asymmetrical half bridge converter. A finite element model is used to predict the core and copper losses and other influencing parameters. Simulation results are presented and analysed the effectiveness of the proposed switched reluctance motor (SRM).

Document type: Article

Electric Car Chassis for Shell Eco Marathon Competition: Design, Modelling and Finite Element Analysis

Scipedia content — Fri, 12 Feb 2021 13:32:30 +0100

The increasing demand for energy efficient electric cars, in the automotive sector, entails the need for improvement of their structures, especially the chassis, because of its multifaceted role on the vehicle dynamic behaviour. The major criteria for the development of electric car chassis are the stiffness and strength enhancement subject to mass reduction as well as cost and time elimination. Towards this direction, this work indicates an integrated methodology of developing an electric car chassis considering the modeling and simulation concurrently. The chassis has been designed in compliance with the regulations of Shell Eco Marathon competition. This methodology is implemented both by the use of our chassis load calculator (CLC) model, which automatically calculates the total loads applied on the vehicle&rsquo

s chassis and by the determination of a worst case stress scenario. Under this extreme stress scenario, the model&rsquo

s output was evaluated for the chassis design and the FEA method was performed by the pre-processor ANSA and the solver Ansys. This method could be characterized as an accurate ultrafast and cost-efficient method.

Document type: Article

Operation Optimization of Multi-District Integrated Energy System Considering Flexible Demand Response of Electric and Thermal Loads

Scipedia content — Fri, 12 Feb 2021 13:31:51 +0100

Multi-district integrated energy system (IES) can make full use of the complementary characteristics of district power and thermal system, and loads in different districts. It can improve the flexibility and economy of system operation, which has a good development prospect. Firstly, based on the general energy transfer model of the district heating network (DHN), the DHN system is described by the basic equations of the heating network and nodes considering the characteristics of the transmission time delay and heat loss in pipelines. A coupling model of DHN and multi-district IES is established. Secondly, the flexible demand response (FDR) model of electric and thermal loads is established. The load characteristics of each district in IES are studied. A shiftable load model based on the electric quantity balance is constructed. Considering the flexibility of the heat demand, a thermal load adjustment model based on the comfort constraint is constructed to make the thermal load elastic and controllable in time and space. Finally, a mixed integer linear programming (MILP) model for operation optimization of multi-district IES with the DHN considering the FDR of electric and thermal loads is established based on the supply and demand sides. The result shows that the proposed model makes full use of the complementary characteristics of electric and thermal loads in different districts. It realizes the coordinated distribution of thermal energy among different districts and improves the efficiency of thermal energy utilization through the DHN. FDR effectively reduces the peak-valley difference of loads. It further reduces the total operating cost by the coordinated operation of the DHN and multi-district IES.

Document type: Article

Electric cars: Are they solution to reduce CO2 emission?

Scipedia content — Fri, 12 Feb 2021 13:31:30 +0100

Reducing CO2 emission is one of the major environmental challenges for transportation. One way to solve this problem is to replace old cars that use fossil fuels (petrol, diesel) with new electric cars. In this paper, the existing model for calculating well-to-wheels CO2 emission during the life cycle of the car (fossil fuel car and electric car) is upgraded. The developed model is used for comparing optimal lifetime and optimal car’s kilometers driven during a lifetime in the replacement process of a fossil fuel car with a new electric car. We find that reducing CO2 emission depends on the type of fossil fuel, and the weight of fossil fuel cars and electric cars. Changing petrol fossil fuel cars with lower weight electric cars have the greatest potential for reducing CO2 emission. However, the introduction of electric cars does not achieve a significant reduction of CO2 emission in countries where electricity is primarily produced in thermal power plants, i. e. in countries with a high emission factor of electricity production. [Projects of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 36010, Grant no. TR 36022 and Grant no. TR 36027]

Document type: Article

Evaluation of the effectiveness of anti-turbulent additives in the oil pipeline transportation

Scipedia content — Fri, 12 Feb 2021 13:30:39 +0100

The authors of the article have developed the computer application allows to determine the value of the friction coefficient λ and anti-turbulent additives efficiency with a high degree of accuracy. The program can be used in the calculations and design of oil pipelines. The paper presents experimental studies of the effect anti-turbulent additives on the magnitude of pressure losses during fluid movement through pipes. The data gained by the developed computer program has been proved by the data of practical application of additives in the real oil pipeline transportation system called Eastern Siberia-Pacific Ocean oil pipeline.

Document type: Article

The social perception of urban transport in the city of Madrid: the application of the Servicescape Model to the bus and underground services

Scipedia content — Fri, 12 Feb 2021 13:29:43 +0100

Purpose This paper is a study of the user’s perception of urban and suburban transport and was carried out in an attempt to compare the social value of various means of transport. The measurement of social perceptions is carried out with regard to ambient conditions, space, signs, front-line employees and other customers as stakeholders of both public transport services. Thus, this paper aims to identify the reasons for individuals’ preferences when choosing one particular means of transport for their daily life. Results The results show that user perceptions of the underground are slightly better than the perceptions of buses; the results also highlight the decent management of both means of transport in terms of quality air, temperature, space, noise, cleanliness, smell and seating facilities. Some modest improvements are recommended to enhance public transportation service delivery. Conclusions This approach reflects the gap between the social perception of a service and companies’ financial situations. Management policies are necessary to improve the service’s social value.

Document type: Article

Site-Specific Propagation Loss Prediction in 4.9 GHz Band Outdoor-to-Indoor Scenario

Scipedia content — Fri, 12 Feb 2021 13:28:34 +0100

Owing to the widespread use of smartphones and various cloud services, user traffic in cellular networks is rapidly increasing. Especially, the traffic congestion is severe in urban areas, and effective service-cell planning is required in the area for efficient radio resource usage. Because many users are also inside high buildings in the urban area, the knowledge of propagation loss characteristics in the outdoor-to-indoor (O2I) scenario is indispensable for the purpose. The ray-tracing simulation has been widely used for service-cell planning, but it has a problem that the propagation loss tends to be underestimated in a typical O2I scenario in which the incident radio waves penetrate indoors through building windows. In this paper, we proposed the extension method of the ray-tracing simulation to solve the problem. In the proposed method, the additional loss factors such as the Fresnel zone shielding loss and the transmission loss by the equivalent dielectric plate were calculated for respective rays to eliminate the penetration loss prediction error. To evaluate the effectiveness of the proposed method, we conducted radio propagation measurements in a high-building environment by using the developed unmanned aerial vehicle (UAV)-based measurement system. The results showed that the penetration loss of direct and reflection rays was significantly underestimated in the ray-tracing simulation and the proposed method could correct the problem. The mean prediction error was improved from 7.0 dB to &minus

0.5 dB, and the standard deviation was also improved from 8.2 dB to 5.3 dB. The results are expected to be utilized for actual service-cell planning in the urban environment.

Document type: Article

Vehicle Trajectory Reconstruction for Signalized Intersections with Low-Frequency Floating Car Data

Scipedia content — Fri, 12 Feb 2021 13:27:54 +0100

Floating car data are beneficial in estimating traffic conditions in wide areas and are playing an increasing role in traffic surveillance. However, widespread application is limited by low-sample frequency which makes it hard to get a complete picture of a vehicle’s motion. An accurate and reliable reconstruction of a vehicle’s trajectory could effectively result in a higher sampling frequency enabling a more accurate estimation of road traffic parameters. Existing methods require additional information such as nearby vehicles, signal timing strategies, and queue patterns which are not always available. To address this problem, this paper presents a method used with low-sample frequency data to reconstruct vehicle trajectories through intersections, without the need for extra information. Furthermore, the additional parameters for the speed-time curve distributions for deceleration rate and acceleration rate are generated. A piecewise deceleration and acceleration model is developed to calculate the acceleration rate for different travel modes in the trajectory. The distribution parameters of the acceleration data for each travel mode are then estimated using a new Expectation Maximization (EM) algorithm. The acceleration statistics are then used to reconstruct the corresponding parts of the trajectory. Compared to the reference trajectories (truth), the test results show that the method developed in this paper achieves improvement in accuracy ranging from 16 to 67% over the commonly used linear interpolation method. In addition, the proposed method is not very sensitive to the sampling interval of the floating car data, unlike the linear interpolation method where the error grows rapidly with increasing sampling interval.

Document type: Article

Human Factors Analysis of Air Traffic Safety Based on HFACS-BN Model

Scipedia content — Fri, 12 Feb 2021 13:27:14 +0100

traffic control (ATC) performance is important to ensure flight safety and the sustainability of aviation growth. To better evaluate the performance of ATC, this paper introduces the HFACS-BN model (HFACS: Human factors analysis and classification system

BN: Bayesian network), which can be combined with the subjective information of relevant experts and the objective data of accident reports to obtain more accurate evaluation results. The human factors of ATC in this paper are derived from screening and analysis of 142 civil and general aviation accidents/incidents related to ATC human factors worldwide from 1980 to 2019, among which the most important 25 HFs are selected to construct the evaluation model. The authors designed and implemented a questionnaire survey based on the HFACS framework and collected valid data from 26 frontline air traffic controllers (ATCO) and experts related to ATC in 2019. Combining the responses with objective data, the noisy MAX model is used to calculate the conditional probability table. The results showed that, among the four levels of human factors, unsafe acts had the greatest influence on ATC Performance (79.4%), while preconditions for safe acts contributed the least (40.3%). The sensitivity analysis indicates the order of major human factors influencing the performance of ATC. Finally, this study contributes to the literature in terms of methodological development and expert empirical analysis, providing data support for human error management intervention of ATC in aviation safety.

Document type: Article

Numerical Study on the Hydrodynamic Characteristics of Submarine Pipelines under the Impact of Real-World Tsunami-Like Waves

Scipedia content — Fri, 12 Feb 2021 13:25:03 +0100

Submarine pipelines have been extensively used for marine oil and gas extraction due to their high efficiency, safety, and low price. However, submarine pipelines are vulnerable to extreme waves (i.e., tsunami waves). Previous research has often used solitary waves as a basis for studying the impacts of tsunami waves on submarine pipelines, although the hydrodynamic characteristics and wave properties drastically differ from those of real-world tsunami waves. This paper numerically investigates the hydrodynamic characteristics of tsunami waves interacting with submarine pipelines, but instead uses an improved wave model to generate a tsunami-like wave that more closely resembles those encountered in the real-world. The tsunami-like wave generated based on a real-world tsunami wave profile recorded during a 2011 tsunami in Japan has been applied. Given the same wave height, simulation results show that peak hydrodynamic forces of the tsunami-like wave are greater than those of the solitary wave. Meanwhile, the duration of the acting force under the tsunami-like wave is much longer than that of the solitary wave. These findings underline the basic reasons for the destructive power of tsunamis. It is also noted that the hydrodynamic forces of the pipeline under the tsunami-like wave increase with wave height, but will decrease as water depth increases. In addition to the single pipeline, the complicated hydrodynamic characteristics of pipelines in tandem arrangement have been also numerically studied. It is believed that the findings drawn from this paper can enhance our understanding of the induced forces on submarine pipelines under extreme tsunami waves.

Document type: Article

An Integrated Variable Speed Limit and ALINEA Ramp Metering Model in the Presence of High Bus Volume

Scipedia content — Fri, 12 Feb 2021 13:24:01 +0100

Under many circumstances, when providing full bus priority methods, urban transport officials have to operate buses in mixed traffic based on their road network limitations. In the case of Istanbul's Metrobus lane, for instance, when the route comes to the pre-designed Bosphorus Bridge, it has no choice but to merge with highway mixed traffic until it gets to the other side. Much has been written on the relative success of implementing Ramp Metering (RM), for example ALINEA (&lsquo

Asservissement line´

aire d&rsquo

entre´

e autoroutie&rsquo

) and Variable Speed Limits (VSL), two of the most widely-used &ldquo

merging congestion&rdquo

management strategies, in both a separate and combined manner. However, there has been no detailed study regarding the combination of these systems in the face of high bus volume. This being the case, the ultimate goal of this study is to bridge this gap by developing and proposing a combination of VSL and RM strategies in the presence of high bus volume (VSL+ALINEA/B). The proposed model has been coded using microscopic simulation software&mdash

VISSIM&mdash

and its vehicle actuated programming (VAP) feature

referred to as VisVAP. For current traffic conditions, the proposed model is able to improve total travel time by 9.0%, lower the number of average delays of mixed traffic and buses by 29.1% and 81.5% respectively, increase average speed by 12.7%, boost bottleneck throughout by 2.8%, and lower fuel consumption, Carbon Monoxide (CO), Nitrogen Oxides (NOx), and Volatile Organic Compounds (VOC) emissions by 17.3% compared to the existing &ldquo

VSL+ALINEA&rdquo

model. The results of the scenario analysis confirmed that the proposed model is not only able to decrease delay times on the Metrobus system but is also able to improve the adverse effects of high bus volume when subject to adjacent mixed traffic flow along highway sections.

Document type: Article

Relationships between risk of causing a motorway crash in Austria and attributes of drivers

Scipedia content — Fri, 12 Feb 2021 13:20:33 +0100

"jats:title"Objective"/jats:title" "jats:p"The emphasis of the study presented in this paper was to identify the attributes of drivers who are prone to cause a motorway crash. It was induced byambitions to enhance the effectiveness of traffic safety campaigns by identifying subgroups of drivers more precisely."/jats:p" "/jats:sec""jats:sec" "jats:title"Method"/jats:title" "jats:p"For this purpose we conducted an accident data analysis of all injury crashes 2012–2014 on Austrian motorways. Since 2012 it is possible for the police to label the “mainly responsible person” for the crash in the Austrian electronic accident recording system. It turned out that the quality of the data had some limitations, which required considerable pre-processing. The analysis by comparing the proportions of “mainly responsible” and “not responsible” drivers was done using descriptive statistics and logistic regression models. The binary characteristic, if a person was, according to the police, mainly responsible for the crash served as response variable. It was regressed on various personal and vehicle characteristics in order to identify their influence on the probability of causing a crash."/jats:p" "/jats:sec""jats:sec" "jats:title"Results/Conclusions"/jats:title" "jats:p"The results yield apparent tendencies, some of which support well-known pattern, e.g., the disproportionally high risk of motorcyclists and - to a lesser extent - young and elderly car drivers to cause an accident. Other results were less expected, e.g., the higher risk of foreign car drivers (compared to Austrian drivers) as well as drivers of light trucks, whereas drivers of heavy trucks revealed a below-average risk of causing a crash. The differences between male and female car drivers were small from young to middle age and fully disappeared in the high age group. There is some evidence that the frequency and experience of driving on a motorway have more influence on the risk of causing a crash than the driver’s gender. From this we conclude that motorway safety campaigns should on the one hand focus on the abovementioned groups of high risk drivers and on the other hand, in terms of car drivers, equally address both male and female drivers."/jats:p" "/jats:sec

Document type: Article

A Deep-Sea Pipeline Skin Effect Electric Heat Tracing System

Scipedia content — Fri, 12 Feb 2021 13:18:53 +0100

In order to ensure deep-water flowline safety, this paper combined the axial temperature distribution model of the submarine pipeline and the distributed parameter circuit model of the skin effect electric heat tracing system

such work is conducive to proving that the heating effect of the skin effect electric heat tracing system depends on the distributed circuit parameters and power frequency of the system. Due to the complexity of the power supply device, the frequency cannot be increased indefinitely. Therefore, for the case that the input of the skin electric heat tracing system is constrained, a generalized predictive control algorithm introducing the input softening factor is proposed, and the constrained generalized predictive control strategy is applied to the electric heating temperature control system of the submarine oil pipeline. Simulation results demonstrated that the control quantity of the skin effect electric heat tracing system is effectively controlled within a constraint range, and also the values of heating power and power frequency are obtained by theoretical calculations rather than empirical estimations. Moreover, compared with the conventional control algorithm, the proposed constrained generalized predictive algorithm unfolds more significant dynamic response and better adaptive adjustment ability, which verifies the feasibility of the proposed control strategy.

Document type: Article

Control parameters analysis, modeling and experiment

Scipedia content — Fri, 12 Feb 2021 13:18:08 +0100

This article presents an in-situ comparative analysis and power quality tests of a newly developed photovoltaic charging system for e-bikes. The various control methods of the inverter are modeled and a single-phase grid-connected inverter is tested under different conditions. Models are constituted for two current control methods

the proportional resonance and the synchronous rotating frames. In order to determine the influence of the control parameters, the system is analyzed analytically in the time domain as well as in the frequency domain by simulation. The tests indicated the resonance instability of the photovoltaic inverter. The passivity impedance-based stability criterion is applied in order to analyze the phenomenon of resonance instability. In conclusion, the phase-locked loop (PLL) bandwidth and control parameters of the current loop have a major effect on the output admittance of the inverter, which should be adjusted to make the system stable.

Document type: Article

Factors Influencing Electric Vehicle Penetration in the EU by 2030: A Model-Based Policy Assessment

Scipedia content — Fri, 12 Feb 2021 13:16:05 +0100

The European Commission (EC) has set ambitious CO"sub"2"/sub" emission reduction objectives for the transport sector by 2050. In this context, most decarbonisation scenarios for transport foresee large market penetration of electric vehicles in 2030 and 2050. The emergence of electrified car mobility is, however, uncertain due to various barriers such as battery costs, range anxiety and dependence on battery recharging networks. Those barriers need to be addressed in the 2020–2030 decade, as this is key to achieving electrification at a large scale in the longer term. The paper explores the uncertainties prevailing in the first decade and the mix of policies to overcome the barriers by quantifying a series of sensitivity analysis scenarios of the evolution of the car markets in the EU Member States and the impacts of each barrier individually. The model used is PRIMES-TREMOVE, which has been developed by E3MLab and constitutes a detailed energy-economic model for the transport sector. Based on model results, the paper assesses the market, energy, emission and cost impacts of various CO"sub"2"/sub" car standards, infrastructure development plans with different geographic coverage and a range of battery cost reductions driven by learning and mass industrial production. The assessment draws on the comparison of 29 sensitivity scenarios for the EU, which show that removing the barriers in the decade 2020–2030 is important for electrification emergence. The results show that difficult policy dilemmas exist between adopting stringent standards and infrastructure of wide coverage to push technology and market development and adverse effects on costs, in case the high cost of batteries persists. However, if the pace of battery cost reductions is fast, a weak policy for standards and infrastructure is not cost-effective and sub-optimal. These policies are shown to have impacts on the competition between pure electric and plug-in hybrid vehicles. Drivers that facilitate electrification also favour the uptake of the former technology, the latter being a reasonable choice only in case the barriers persist and obstruct electrification.

Document type: Article

Ride Blending Control for Electric Vehicles

Scipedia content — Fri, 12 Feb 2021 13:14:54 +0100

Vehicles equipped with in-wheel motors (IWMs) feature advanced control functions that allow for enhanced vehicle dynamics and stability. However, these improvements occur to the detriment of ride comfort due to the increased unsprung mass. This study investigates the driving comfort enhancement in electric vehicles that can be achieved through blended control of IWMs and active suspensions (ASs). The term &ldquo

ride blending&rdquo

, coined in a previous authors&rsquo

work and herein retained, is proposed by analogy with the brake blending to identify the blended action of IWMs and ASs. In the present work, the superior performance of the ride blending control is demonstrated against several driving manoeuvres typically used for the evaluation of the ride quality. The effectiveness of the proposed ride blending control is confirmed by the improved key performance indexes associated with driving comfort and active safety. The simulation results refer to the comparison of the conventional sport utility vehicle (SUV) equipped with a passive suspension system and its electric version provided with ride blending control. The simulation analysis is conducted with an experimentally validated vehicle model in CarMaker®

and MATLAB/Simulink co-simulation environment including high-fidelity vehicle subsystems models.

Document type: Article

A Real-Car Experiment of a Dynamic Wireless Power Transfer System Based on Parallel-Series Resonant Topology

Scipedia content — Fri, 12 Feb 2021 13:13:06 +0100

short mileage and long charging times are problems facing electric vehicles (EVs), and dynamic wireless power transfer (WPT) systems are one of the most effective solutions to overcome these shortcomings. This paper proposes a dynamic WPT system consisting of several stationary primary underground coils and a secondary coil on an EV. The dynamic WPT system employed solenoid coils that were superior to circular coils in terms of misalignment to the traveling direction. A dynamic WPT system rated at 25 kW was designed, constructed, and tested to verify the principles of operation

that is, the capability of supplying electric power continuously.

Document type: Article

Measuring Retiming Responses of Passengers to a Prepeak Discount Fare by Tracing Smart Card Data: A Practical Experiment in the Beijing Subway

Scipedia content — Fri, 12 Feb 2021 13:11:19 +0100

Understanding passengers’ responses to fare changes is the basis to design reasonable price policies. This work aims to explore retiming responses of travelers changing departure times due to a prepeak discount pricing strategy in the Beijing subway in China, using smart card records from an automatic fare collection (AFC) system. First, a new set of classification indicators is established to segment passengers through a two-step clustering approach. Then, the potentially influenced passengers for the fare policy are identified, and the shifted passengers who changed their departure time are detected by tracing changes in passengers’ expected departure times before and after the policy. Lastly, the fare elasticity of departure time is defined to measure the retiming responses of passengers. Two scenarios are studied of one month (short term) and six months (middle term) after the policy. The retiming elasticity of different passenger groups, retiming elasticity over time, and retiming elasticity functions of shifted time are measured. The results show that there are considerable differences in the retiming elasticities of different passenger groups; low-frequency passengers are more sensitive to discount fares than high-frequency passengers. The retiming elasticity decreases greatly with increasing shifted time, and 30 minutes is almost the maximum acceptable shifted time for passengers. Moreover, the retiming elasticity of passengers in the middle term is approximately twice that in the short term. Applications of fare optimization are also executed, and the results suggest that optimizing the valid time window of the discount fares is a feasible way to improve the congestion relief effect of the policy, while policy makers should be cautious to change fare structures and increase discounts.

Document type: Article

Locational pricing trumps wholesale pricing

Scipedia content — Fri, 12 Feb 2021 13:05:21 +0100

DC distribution systems (DCDSs) are a promising alternative to AC systems because they remove AC-DC conversions between renewable sources and loads. Their unique features compared to AC include low system inertia, strict power limits and power&ndash

voltage coupling. In a liberalised electricity market, merely applying an AC market design to a DCDS cannot guarantee the latter&rsquo

s supply security and voltage stability

new markets must be designed to meet DC challenges. This article identifies the key design options of DCDS electricity markets. To identify these options, we develop a comprehensive design framework for local electricity markets

to our knowledge, we provide the first such analysis. Whereas previous studies focus on separate aspects of DCDS markets, we widen the scope to include the role of market architecture and investigate the arrangements of sub-markets. As an illustration, we demonstrate three promising DCDS market designs that can be defined in our framework, and provide a first assessment of their performance.

Document type: Article

Factors Affecting the Uptake of Hybrid and Electric Vehicles in the European Union

Scipedia content — Fri, 12 Feb 2021 13:04:03 +0100

This paper explores the factors affecting the uptake of hybrid and electric vehicles in the European Union (EU) using data from two extensive cross-sectional surveys. Each survey consists of 26,500 responses to a questionnaire that combines socio-economic and behavioral aspects. The share of respondents across the EU stating that they would certainly or probably consider purchasing a hybrid or a battery-powered electric vehicle (H&EV) in the near future rose from 32% in 2014 to 37.4% in 2018. There is, however, a high variability among EU member states, as well as across different socio-economic groups. Propensity is highly correlated with income, educational attainment, and urbanization level. In order to address the high degree of collinearity, we applied a machine learning classification model to analyze and explain the interaction between the variables that affected the expressed propensity to purchase such a vehicle. The findings highlight something largely missing from the literature, namely that local conditions and regional variation are a major, if not decisive, factor regarding purchasing choices. Seen from a policy perspective, this conclusion may provide guidance regarding how to support the take up of H&EVs through measures that are tailored to the specific needs at the local level.

Document type: Article

Competition and Sustainability Development of a Multi-Airport Region: A Case Study of the Guangdong–Hong Kong–Macao Greater Bay Area

Scipedia content — Fri, 12 Feb 2021 13:03:42 +0100

new era in the development of multi-airport regions (MARs) has been in China, especially in the construction of global urban areas such as the Guangdong&ndash

Hong Kong&ndash

Macao Greater Bay Area (GBA). In order to better understand competition and provide significant advice to support sustainable development of Chinese MARs, this paper takes the GBA-MAR as an example, and then explores the competition between airports in this multi-airport region based on route level and its impact on passenger airport choice using three liner models. According to our findings, competition is concentrated on a few air routes in the Northeast&ndash

East Coastal region and the Asia-Pacific region, in which all three airports operate. Although the domestic market of the GBA-MAR has been relatively mature, the international air transport market is still left with considerable room, which is also reflected in connections to the world&rsquo

s cities and tourist destinations. In addition, the research also found that different airport brands created by route type significantly affected passenger airport choice. Overall, the study revealed that whether from a supply or demand aspect, competition between airports in a multi-airport region&mdash

not just airline competition in a single airport&mdash

is an important topic.

Document type: Article

Research on Local Dynamic Path Planning Method for Intelligent Vehicle Lane-Changing

Scipedia content — Fri, 12 Feb 2021 13:03:18 +0100

A local dynamic path planning method is proposed to compensate for the lack of consideration of the movement state of surrounding vehicles, the poor comfort, and the low traffic efficiency when the existing vehicle changes lanes automatically. Firstly, the cubic polynomial is predefined, and the optimal track path is solved. According to the real-time information of environment perception, the model is continuously modified by acquiring real-time information in the course of path planning, and the regional safety of the vehicle is realized. The Carsim and simulink simulation results and actual vehicle verification show that, compared with the traditional nondynamic research method, this method can effectively solve the problem that the vehicle speed variation and the sudden intrusions of the vehicle leading to the compulsory operation of the vehicle during the course of lane-changing. The safety is also improved. In order to ensure the vehicle comfort and stability, the lane-changing time is shortened by 20%, and the efficiency of lane-changing is improved obviously.

Document type: Article

Why Shared Bikes of Free-Floating Systems Were Parked Out of Order? A Preliminary Study based on Factor Analysis

Scipedia content — Fri, 12 Feb 2021 13:02:13 +0100

Free-floating bicycle-sharing systems are an important component of sustainable transport. China&rsquo

s bicycle-sharing schemes have experienced ups and downs in the past three years, and there are a lot of related studies, but there are relatively few studies on the causes of disorderly parking of shared bikes. In this study, an open questionnaire is used to widely collect the causes of the disorderly parking of shared bicycles from users. Through factor analysis, six factors and 32 criteria for the causes of disorderly parking are constructed. Factor 1 &lsquo

supervision and management of enterprises&rsquo

factor 2 &lsquo

supervision and management of users&rsquo

factor 3 &lsquo

parking space&rsquo

factor 4 &lsquo

guidance of parking shared bikes&rsquo

factor 5 &lsquo

user self-discipline&rsquo

factor 6 &lsquo

operation and maintenance&rsquo

. It requires the cooperation of multiple parties to solve the problem of disorderly parking of shared bicycles.

Document type: Article

Time-Dependent Pricing for High-Speed Railway in China Based on Revenue Management

Scipedia content — Fri, 12 Feb 2021 13:01:30 +0100

High-speed railway (HSR) is recognized as a green transportation mode with lower energy consumption and less pollution emission than other transportation. At present, China has the largest HSR network globally, but the maximum revenue of railway transportation corporations has not been realized. In order to make HSR achieve a favorable position within the fierce competition in the market, increase corporate revenue, and achieve the sustainable development of HSR and railway corporations, we introduce the concept of revenue management in HSR operations and propose an innovative model to optimize the price and seat allocation for HSR simultaneously. In the study, we formulate the optimization problem as a mixed-integer nonlinear programming (MINLP) model, which appropriately captures passengers&rsquo

choice behavior. To reduce the computational complexity, we further transform the proposed MINLP model into an equivalent model. Finally, the effectiveness of both the proposed model and solution algorithm are tested and validated by numerical experiments. The research results show that the model can flexibly adjust the price and seat allocation of the corresponding ticketing period according to the passenger demand, and increase the total expected revenue by 5.92% without increasing the capacity.

Document type: Article

Selected Aspects of Using the Telemetry Method in Synthesis of RelNav System for Air Traffic Control

Scipedia content — Fri, 12 Feb 2021 12:57:34 +0100

Accuracy is an important factor in air traffic management which is why high requirements are necessary for each navigation system. The aim of this article is to describe the principles of the RelNav system and telemetry and their accuracy. We present the algorithms of the relative navigation system, which could be used for air traffic control in the case of the unavailability of satellite navigation system signals. This article sums up the different positioning methods, and deals with the accuracy of the relative navigation system (RelNav). Furthermore, the article considers the factors that influence the positioning accuracy. For this task, a computer simulation was created to evaluate the accuracy of the telemetric method. Next, we discuss the principles of telemetry and algorithms for calculating the position of the flying object (FO).

Document type: Article

Attitude Toward Sustainable Transport as a Function of Source and Argument Reliability and Anticipated Emotions

Scipedia content — Fri, 12 Feb 2021 12:56:48 +0100

The progressive development of mass communication has allowed the understanding and management of the persuasion process in a more systematic way. However, nowadays, persuasive campaigns still hardly result in behavior changes, particularly around concerns of the promotion of more sustainable lifestyles. Thus, it appears essential to investigate which dimensions are more effective in influencing people&rsquo

s pro-environmental actions. Relying on the conceptual frameworks provided by the elaboration likelihood model (ELM) and the model of goal-directed behavior (MGB), a questionnaire study (n = 380 urban residents) was carried out on the psycho-social antecedents of the intention to use sustainable means of transport. Structural equation modeling showed the mediating role of attitudes toward sustainable transport between ELM persuasion features (i.e., source reliability and argument reliability) and behavioral intention. Positive and negative anticipated emotions, derived from MGB, predict source reliability (the former) and argument reliability (the latter), respectively.

Document type: Article

Correction to: The vibrations induced by surface irregularities in road pavements – a Matlab® approach

Scipedia content — Fri, 12 Feb 2021 12:55:08 +0100

fter publication of this article [1], it is noticed the article contained an error with eq. 12, the c s should be squared. The correct eq. 12 is provided below

Document type: Article

Effect of Pipe Diameter and Inlet Parameters on Liquid CO"sub"2"/sub" Flow in Transportation by Pipeline with Large Height Difference

Scipedia content — Fri, 12 Feb 2021 12:53:03 +0100

Fire prevention and extinguishing and CO2 sequestration in coal mine gob require continuous transportation of liquid CO2 in pipelines with large height difference (from ground to underground). However, the temperature and pressure variation of liquid CO2 in pipelines with large height difference is still unclear, which hinders the design of a liquid CO2 pipeline transportation system. The influence of pipe diameter and inlet parameters (temperature and pressure) on the variation of temperature and pressure of liquid CO2 along the 1000 m vertical pipeline was studied in this paper. The study found that for each pipeline diameter considered there existed a range of flowrates where safe flow conditions could be ensured, at which no phase transition occurs throughout the length of the pipeline. When the transporting flow is larger than the maximum limit flow, phase transition occurs dramatically, which will lead to a sudden drop in temperature and pressure. When the transporting flow rate is lower than the minimum limit flow rate, phase transition of CO2 occurs slowly along the pipeline. According to the requirement of underground fire prevention and extinguishing for transporting flow rate and the economic cost of the pipeline system, the optimum diameter is 32 mm, and the corresponding safe transporting flow range is 507&ndash

13,826 kg/h. In addition, when the inlet pressure is constant, if the inlet temperature is too high, phase transition of CO2 occurs dramatically at the entrance. For a 1000 m vertical pipe with diameter of 32 mm, when the inlet pressure is 14 bar, 16 bar, 18 bar, 20 bar, 22 bar, 24 bar, the corresponding maximum allowable inlet temperatures are &minus

30 °

C, &minus

26 °

23 °

19 °

16 °

C and &minus

13 °

C, respectively. This research has significant guidance for safety transportation scheme of liquid CO2 from coal mine surface to underground.

Document type: Article

A Review

Scipedia content — Fri, 12 Feb 2021 12:52:35 +0100

Structural disaster damage detection and characterization is one of the oldest remote sensing challenges, and the utility of virtually every type of active and passive sensor deployed on various air- and spaceborne platforms has been assessed. The proliferation and growing sophistication of unmanned aerial vehicles (UAVs) in recent years has opened up many new opportunities for damage mapping, due to the high spatial resolution, the resulting stereo images and derivatives, and the flexibility of the platform. This study provides a comprehensive review of how UAV-based damage mapping has evolved from providing simple descriptive overviews of a disaster science, to more sophisticated texture and segmentation-based approaches, and finally to studies using advanced deep learning approaches, as well as multi-temporal and multi-perspective imagery to provide comprehensive damage descriptions. The paper further reviews studies on the utility of the developed mapping strategies and image processing pipelines for first responders, focusing especially on outcomes of two recent European research projects, RECONASS (Reconstruction and Recovery Planning: Rapid and Continuously Updated Construction Damage, and Related Needs Assessment) and INACHUS (Technological and Methodological Solutions for Integrated Wide Area Situation Awareness and Survivor Localization to Support Search and Rescue Teams). Finally, recent and emerging developments are reviewed, such as recent improvements in machine learning, increasing mapping autonomy, damage mapping in interior, GPS-denied environments, the utility of UAVs for infrastructure mapping and maintenance, as well as the emergence of UAVs with robotic abilities.

Document type: Article

Feature selection and extraction in spatiotemporal traffic forecasting: a systematic literature review

Scipedia content — Fri, 12 Feb 2021 12:51:14 +0100

A spatiotemporal approach that simultaneously utilises both spatial and temporal relationships is gaining scientific interest in the field of traffic flow forecasting. Accurate identification of the spatiotemporal structure (dependencies amongst traffic flows in space and time) plays a critical role in modern traffic forecasting methodologies, and recent developments of data-driven feature selection and extraction methods allow the identification of complex relationships. This paper systematically reviews studies that apply feature selection and extraction methods for spatiotemporal traffic forecasting. The reviewed bibliographic database includes 211 publications and covers the period from early 1984 to March 2018. A synthesis of bibliographic sources clarifies the advantages and disadvantages of different feature selection and extraction methods for learning the spatiotemporal structure and discovers trends in their applications. We conclude that there is a clear need for development of comprehensive guidelines for selecting appropriate spatiotemporal feature selection and extraction methods for urban traffic forecasting.

Document type: Article

Port-2-Port Communication Enhancing Short Sea Shipping Performance: The Case Study of Cyprus and the Eastern Mediterranean

Scipedia content — Fri, 12 Feb 2021 12:50:58 +0100

The sustainability of Short Sea Shipping (SSS) is central to a clean, safe, and efficient European Union (EU) transport system. We report on key challenges for advancing reliability, quality, and safety, and removing unnecessary costs and delays at SSS hubs, with a particular focus on Cyprus and the Eastern Mediterranean. Specifically, we consider the effect of port-2-port (P2P) communication on port efficiency by investigating the factors influencing the various waiting times at the Port of Limassol, both from a qualitative and a quantitative perspective. The qualitative results are based on the views of key stakeholders involved in the port call process. The quantitative analysis relies on data from over 8000 port calls during 2017&ndash

2018, which are analyzed with respect to ship type, port of origin, and shipping agent. The calculated Key Performance Indicators (KPIs) include arrival punctuality, berth waiting, and berth utilization. The analysis clearly reveals considerable variation in agent performance regarding the KPIs, suggesting a lack of attention to the social aspect of a port&rsquo

s socio-technical system. We propose measures for improving agent performance based on the principles of Port Collaborative Decision Making (PortCDM), including P2P communication, data sharing and transparency among all involved in a port call process including the agents, and open dissemination of agent-specific KPIs.

Document type: Article

The role of equity in urban public transport planning in Brazil

Scipedia content — Fri, 12 Feb 2021 12:48:08 +0100

Embora a noção de equidade seja considerada primordial no emergente paradigma da mobilidade urbana sustentável, o planejamento da mobilidade tem sido acusado de contribuir para a produção e a consolidação de desigualdades sociais e espaciais relacionadas à provisão e organização do transporte coletivo urbano, principalmente no contexto de países em desenvolvimento. Este artigo investiga em que medida planejadores atuantes em cidades brasileiras estão cientes de iniquidades relacionadas ao transporte e a forma como compreendem o papel do transporte em relação a objetivos sociais. Diferentemente do que a literatura sugere, resultados da survey conduzida para este estudo indicam que, no Brasil, planejadores de transportes reconhecem certas associações entre privação socioeconômica e deficiências na oferta de transporte coletivo urbano, mas não necessariamente identificam no processo de planejamento fatores que levam à produção de desigualdades. Tampouco compreendem a ideia de equidade social como central no paradigma de mobilidade urbana sustentável. [The notion of equity is primordial in the emerging paradigm of sustainable urban mobility. However, especially in the developing context, transport planning has been blamed for producing social and spatial inequities, related to lacks of provision and organisational inadequacies of urban collective transport. This article investigates the extent to which practitioners in Brazilian cities are aware of iniquities associated with transport and how they understand the interrelationships between transport and social issues. Differently from what the academic literature suggests, results of the survey conducted for this study indicate that transport planners in Brazil recognise associations between socioeconomic deprivation and deficiencies in the provision of urban public transport, but they do not necessarily hold the planning process responsible for the production of these inequalities, nor do they understand the idea of social equity as a pillar of the sustainable urban mobility paradigm.]

Document type: Article

Sensors in Intelligent Transportation Systems

Scipedia content — Fri, 12 Feb 2021 12:47:09 +0100

Document type: Article

Does driving-day-based tradable credit scheme outperform license plate rationing? Examination considering transaction cost

Scipedia content — Fri, 12 Feb 2021 12:44:58 +0100

This article models a novel driving-day-based tradable credit scheme (DD-TCS) to alleviate urban traffic congestion. In this model, car-using allowances (in terms of the number of days in a month, termed as “credit”) are freely and uniformly allocated to all travellers, who are also allowed to trade them in a market according to his/her travel needs (e.g. driving more or fewer days than the free endowment). As opposed to most studies on TCS, this paper explicitly considers the transaction cost (e.g. information cost of finding potential traders) in the trading market. To assess the feasibility of DD-TCS, we compare it against the license plate rationing (LPR) scheme, which has been practically implemented in many cities such as Beijing and Chengdu in China. Taking the performance of LPR as a benchmark, we quantify the threshold values of the transaction cost in DD-TCS when the two schemes yield equivalent performance (in terms of the total generalized cost). In numerical studies, we also compare the DD-TCS and LPR with the no-action case and the congestion pricing case (representing the theoretical optimum). Results show that both DD-TCS and LPR outperform the no-action case under certain conditions. With small transaction cost, DD-TCS may achieve a lower system cost that can be very close to the ideal optimum. In addition, parameter analysis shows that DD-TCS performs better than LPR in a wide range of transaction cost, where the threshold values appear to account for a considerable portion of the auto travel time. This implies that DD-TCS will be more appealing than LPR in practice because a transaction cost lower than the extremely large threshold values can be easily achieved for the trading market, e.g. via a mobile platform and modern communication techniques.

Document type: Article

Quest for Sustainability: Life-Cycle Emissions Assessment of Electric Vehicles Considering Newer Li-Ion Batteries

Scipedia content — Fri, 12 Feb 2021 12:36:45 +0100

The number of battery electric vehicle models available in the market has been increasing, as well as their battery capacity, and these trends are likely to continue in the future as sustainable transportation goals rise in importance, supported by advances in battery chemistry and technology. Given the rapid pace of these advances, the impact of new chemistries, e.g., lithium-manganese rich cathode materials and silicon/graphite anodes, has not yet been thoroughly considered in the literature. This research estimates life cycle greenhouse gas and other air pollutants emissions of battery electric vehicles with different battery chemistries, including the above advances. The analysis methodology, which uses the greenhouse gases, regulated emissions, and energy use in transportation (GREET) life-cycle assessment model, considers 8 battery types, 13 electricity generation mixes with different predominant primary energy sources, and 4 vehicle segments (small, medium, large, and sport utility vehicles), represented by prototype vehicles, with both battery replacement and non-replacement during the life cycle. Outputs are expressed as emissions ratios to the equivalent petrol internal combustion engine vehicle and two-way analysis of variance is used to test results for statistical significance. Results show that newer Li-ion battery technology can yield significant improvements over older battery chemistries, which can be as high as 60% emissions reduction, depending on pollutant type and electricity generation mix. This research was funded by Fundação para a Ciência e a Tecnologia, grant number UID/Multi/00308/2019, INESC-Coimbra R&D project “Alternative Fuel Vehicles”. info:eu-repo/semantics/publishedVersion

Document type: Article

Identifying the Main Opportunities and Challenges from the Implementation of a Port Energy Management System: A SWOT/PESTLE Analysis

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

Climate change is among the greatest environmental threats facing the globe today and the abatement of greenhouse gas (GHG) emissions is concerning all the industrial sectors contributing to the problem. The maritime transport sector has already implemented several measures for energy efficiency for the reduction of its GHG emissions, including both vessels and ports. This paper focuses on the prospects and challenges facing the development of a port energy management system. It analyzes the main factors which exert an impact on such a plan and that need to be taken into account for its successful implementation. A SWOT/PESTLE analysis is utilized for the identification of the political, economic, social, technological, legal and environmental factors that have a positive or negative effect on the adoption and successful implementation of a port energy management system. This analysis is based on empirical data from two leading North-European port authorities. Given the fact that ports are currently focusing on the reduction of their energy consumption, this paper&rsquo

s results have particular significance in that they could enlighten and inform the adoption of a port energy management plan within ports.

Document type: Article

Design and Implementation of a Blockchain-Based Energy Trading Platform for Electric Vehicles in Smart Campus Parking Lots

Scipedia content — Fri, 12 Feb 2021 12:33:54 +0100

This paper proposes a blockchain-based energy trading platform for electric vehicles in smart campus parking lots. Smart parking lots are smart places capable of supporting both parking and charging services for electric vehicles. The electric vehicle owner may want to charge energy at a low price and sell it during peak hours at a higher price. The proposed system architecture consists of two layers: the physical infrastructure layer and the cyber infrastructure layer. The physical infrastructure layer represents all of the physical components located in the campus distribution power system, such as electric vehicles charging stations, transformers, and electric feeders, while the cyber infrastructure layer supports the operation of the physical infrastructure layer and enables selling/buying energy among participants. Blockchain technology is a promising candidate to facilitate auditability and traceability of energy transactions among participants. A real case of a parking lot with a realistic parking pattern in a university campus is considered. The system consists of a university control center and various parking lot local controllers (PLLCs). The PLLC broadcasts the electricity demand and the grid price, and each electric vehicle owner decides whether to charge/discharge based on their benefits. The proposed system is implemented on Hyperledger Fabric. Participants, assets, transactions, and smart contracts are defined and discussed. Two scenarios are considered. The first scenario represents energy trading between electric vehicles as sellers and the PLLC as a buyer, while the second scenario involves energy trading between electric vehicles as buyers and the PLLC as a seller. The proposed platform provides profits for participants, as well as enables balancing for the university load demand locally.

Document type: Article

PDMS-FBG-based fiber optic system for traffic monitoring in urban areas

Scipedia content — Fri, 12 Feb 2021 12:32:48 +0100

This article introduces fiber Bragg grating (FBG) system for monitoring selected traffic flow parameters in urban areas. The system is able to monitor traffic density or speed of cars driving in single lane. The proposed system consists of five Bragg gratings encapsulated in Polydimethylsiloxane polymer and is characterized by easy and inexpensive installation in the milled upper layer of the road covered with an asphalt mixture. The results of first operational tests presented in this study include 3978 passing vehicles of various specifications. The system's vehicle detection success rate is 99.62%. And further, a mean absolute error 1.35 kph and a relative error 2.62% when measuring vehicle speed. Web of Science 8 127658 127648

Document type: Article

Battery Sizing for Electric Vehicles Based on Real Driving Patterns in Thailand

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

The rising population in suburban areas have led to an increasing demand for commuter buses. Coupled with a desire to reduce pollution from the daily routine of traveling and transportation, electric vehicles have become more interesting as an alternative placement for internal combustion engine vehicles. However, in comparison to those conventional vehicles, electric vehicles have an issue of limited driving range. One of the main challenges in designing electric vehicles (EVs) is to estimate the size and power of energy storage system, i.e., battery pack, for any specific application. Reliable information on energy consumption of vehicle of interest is therefore necessary for a successful EV implementation in terms of both performance and cost. However, energy consumption usually depends on several factors such as traffic conditions, driving cycle, velocities, road topology, etc. This paper presents an energy consumption analysis of electric vehicle in three different route types i.e., closed-area, inter-city, and local feeder operated by campus tram and shuttle bus. The driving data of NGV campus trams operating in a university located in suburban Bangkok and that of shuttle buses operating between local areas and en route to the city were collected and the corresponding representative driving cycles for each route were generated. The purpose of this study was to carry out a battery sizing based on the fulfilment of power requirements from the representative real driving pattern in Thailand. The real driving cycle data i.e., velocity and vehicle global position were collected through a GPS-based piece of equipment, VBOX. Three campus driving data types were gathered to achieve a suitable dimensioning of battery systems for electrified university public buses.

Document type: Article

An Inverse Transient-Based Optimization Approach to Fault Examination in Water Distribution Networks

Scipedia content — Fri, 12 Feb 2021 12:30:08 +0100

This research introduces an inverse transient-based optimization approach to automatically detect potential faults, such as leaks, partial blockages, and distributed deteriorations, within pipelines or a water distribution network (WDN). The optimization approach is named the Pipeline Examination Ordinal Symbiotic Organism Search (PEOS). A modified steady hydraulic model considering the effects of pipe aging within a system is used to determine the steady nodal heads and piping flow rates. After applying a transient excitation, the transient behaviors in the system are analyzed using the method of characteristics (MOC). A preliminary screening mechanism is adopted to sift the initial organisms (solutions) to perform better to reduce most of the unnecessary calculations caused by incorrect solutions within the PEOS framework. Further, a symbiotic organism search (SOS) imitates symbiotic relationship strategies to move organisms toward the current optimal organism and eliminate the worst ones. Two experiments on leak and blockage detection in a single pipeline that have been presented in the literature were used to verify the applicability of the proposed approach. Two hypothetical WDNs, including a small-scale and large-scale system, were considered to validate the efficiency, accuracy, and robustness of the proposed approach. The simulation results indicated that the proposed approach obtained more reliable and efficient optimal results than other algorithms did. We believe the proposed fault detection approach is a promising technique in detecting faults in field applications.

Document type: Article

Measurement of Airport Efficiency. The Case of Colombia

Scipedia content — Fri, 12 Feb 2021 12:29:27 +0100

"jats:p"Since the mid-1990s, Colombia’s main airports (including those with the highest traffic) have been privatized, transferring governance to private operators. The remaining airports in the network (the smallest ones) continue with public governance. Based on this, the objective of this research article is to know, analyse and even measure the airport efficiency in a context of structural reform and at the same time compare this with the measure in airports with public governance. The methodology used to carry out the study is the Data Envelopment Analysis, and this methodology uses only “technical variables” (that is, only those related to infrastructure). The main results of the research reveal higher efficiency indices in the major (or more important) airports, almost all of them under private governance, although there is also a group of them (usually very small airports) with very low efficiency levels.

Document type: Article

Combined Effects of Aircraft, Rail, and Road Traffic Noise on Total Noise Annoyance—A Cross-Sectional Study in Innsbruck

Scipedia content — Fri, 12 Feb 2021 12:27:59 +0100

Noise legislation in Austria does not provide an assessment of the cumulative effect of noise from different sources. The desire of citizens for a total noise assessment is getting stronger. Within the pilot project &ldquo

Gesamtlä

rmbetrachtung&rdquo

(Total Noise Investigation) Innsbruck, data from 1031 face-to-face interviews were correlated with exposure data from road, rail and air traffic noise. The interviews were selected in clusters according to the exposure combinations of these three sources. In addition to exposure-response relationships, it has also been found that the annoyance response to air and rail traffic noise is independent of the background noise from road traffic. The total noise annoyance response shows a cumulative effect in each source considered. From the source specific exposure-response relationships, a total noise assessment model based on the annoyance equivalents model was developed. This model is more suitable than the dominant source model and thus also considerable for legal application.

Document type: Article

The Welfare Effects of Transportation Infrastructure Improvements

Scipedia content — Thu, 11 Feb 2021 14:45:07 +0100

We develop a general equilibrium geographic framework to characterize the welfare effect of transportation infrastructure investments. We tackle three distinct but conflating challenges: First, we offer an analytical characterization of the routing problem and, in particular, how infrastructure investment between any two connected locations decreases the total trade costs between all pairs of locations. Second, we characterize how this cost reduction affects welfare within a standard general equilibrium geography setup where market inefficiencies arise due to agglomeration and dispersion spillovers. Finally, we show how our framework admits analytical characterizations of traffic congestion, which creates a critical – albeit tractable – feedback loop between trade costs and the general equilibrium economic system. We apply these results to calculate the welfare effects of improving each of the thousands of segments of the U.S. national highway network. We find large but heterogeneous welfare effects, with the largest gains concentrated in metropolitan areas and along important trading corridors.

Should Electric Vehicle Drivers Pay a Mileage Tax?

Scipedia content — Thu, 11 Feb 2021 14:39:59 +0100

In many countries, the revenue from gasoline taxes is used to fund highways and other transportation infrastructure. As the number of electric vehicles on the road increases, this raises questions about the effectiveness and equity of this financing mechanism. In this paper, we ask whether electric vehicle drivers should pay a mileage tax. Though the gasoline tax has been traditionally viewed as a benefits tax, we instead take the perspective of economic efficiency. We derive a condition for the optimal electric vehicle mileage tax that highlights a key trade-off. On the one hand, there are externalities from driving, including traffic congestion and accidents, that imply a mileage tax is efficient. On the other hand, gasoline tends to be underpriced, so a low (or even negative) mileage tax might have efficiency benefits in encouraging substitution away from gasoline-powered vehicles. We then turn to an empirical analysis aimed at better understanding the current policy landscape for electric vehicles in the United States. Using newly available, nationally representative microdata, we calculate that electric vehicles have reduced gasoline tax revenues by $250 million annually. We show that the forgone tax revenue is highly concentrated in a handful of states and is highly regressive, as most electric vehicles are driven by high-income households, and we discuss how this motivates and informs optimal policy.

BGP - Link State (BGP-LS) Advertisement of IGP Traffic Engineering Performance Metric Extensions

Scipedia content — Thu, 11 Feb 2021 14:36:39 +0100

This document defines new BGP-LS TLVs in order to carry the IGP Traffic Engineering Metric Extensions defined in the IS-IS and OSPF protocols.

Seismic hazards to Arctic Islands pipelines

Scipedia content — Thu, 11 Feb 2021 14:36:10 +0100

Connecting to Economic Opportunity: The Role of Public Transport in Promoting Women’s Employment in Lima

Scipedia content — Thu, 11 Feb 2021 14:35:40 +0100

Limited access to safe transportation is one of the greatest challenges to labor force participation faced by women in developing countries. This paper quantifies the causal impacts of improved urban transport systems in women’s employment outcomes, looking at Bus Rapid Transit (BRT) and elevated light rail investments in the metropolitan region of Lima, Peru. We find large gains in employment and earnings per hour among women, and not for men, due to these investments. Most of the gains arise on the extensive margin, with more women being employed, but employment does not appear to be of higher quality than that for comparison groups. We find also evidence of an increase in the use of public transport. Results are robust to alternative specifications and we do not find evidence that they are driven by neighborhood composition changes or reorganization of economic activity. Overall, these findings suggest that infrastructure investments that make it faster and safer for women to use public transport can generate important labor market impacts for women who reside in the area of influence of the improved infrastructure.

Signaling RSVP-TE Tunnels on a Shared MPLS Forwarding Plane

Scipedia content — Thu, 11 Feb 2021 14:32:33 +0100

The scale of MPLS RSVP-TE networks has grown, so the number of Label Switched Paths (LSPs) supported by individual network elements has increased. Various implementation recommendations have been proposed to manage the resulting increase in control plane state. However, those changes have had no effect on the number of labels that a transit Label Switching Router (LSR) has to support in the forwarding plane. That number is governed by the number of LSPs transiting or terminated at the LSR and is directly related to the total LSP state in the control plane. This document defines a mechanism to prevent the maximum size of the label space limit on an LSR from being a constraint to control plane scaling on that node. It introduces the notion of pre-installed 'per Traffic Engineering (TE) link labels' that can be shared by MPLS RSVP-TE LSPs that traverse these TE links. This approach significantly reduces the forwarding plane state required to support a large number of LSPs. This couples the feature benefits of the RSVP-TE control plane with the simplicity of the Segment Routing MPLS forwarding plane.

OSPF Routing with Cross-Address Family Traffic Engineering Tunnels

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

When using Traffic Engineering (TE) in a dual-stack IPv4/IPv6 network the Multiprotocol Label Switching (MPLS) TE Label Switched Paths (LSP) infrastructure may be duplicated, even if the destination IPv4 and IPv6 addresses belong to the same remote router. In order to achieve an integrated MPLS TE LSP infrastructure, OSPF routes must be computed over MPLS TE tunnels created using information propagated in another OSPF instance. This is solved by advertising cross-address family (X-AF) OSPF TE information. This document describes an update to RFC5786 that allows for the easy identification of a router's local X-AF IP addresses.

IS-IS Traffic Engineering (TE) Metric Extensions

Scipedia content — Thu, 11 Feb 2021 14:14:47 +0100

In certain networks, such as, but not limited to, financial information networks (e.g., stock market data providers), network performance information (e.g., link propagation delay) is becoming critical to data path selection. This document describes common extensions to RFC 3630 "Traffic Engineering (TE) Extensions to OSPF Version 2" and RFC 5329 "Traffic Engineering Extensions to OSPF Version 3" to enable network performance information to be distributed in a scalable fashion. The information distributed using OSPF TE Metric Extensions can then be used to make path selection decisions based on network performance. Note that this document only covers the mechanisms by which network performance information is distributed. The mechanisms for measuring network performance information or using that information, once distributed, are outside the scope of this document.

Path Computation Element Communication Protocol (PCEP) Extensions for Segment Routing

Scipedia content — Thu, 11 Feb 2021 14:14:33 +0100

Segment Routing (SR) enables any head-end node to select any path without relying on a hop-by-hop signaling technique (e.g., LDP or RSVP-TE). It depends only on "segments" that are advertised by link- state Interior Gateway Protocols (IGPs). A Segment Routing Path can be derived from a variety of mechanisms, including an IGP Shortest Path Tree (SPT), explicit configuration, or a Path Computation Element (PCE). This document specifies extensions to the Path Computation Element Communication Protocol (PCEP) that allow a stateful PCE to compute and initiate Traffic Engineering (TE) paths, as well as a PCC to request a path subject to certain constraints and optimization criteria in SR networks.

Riders on the Storm

Scipedia content — Thu, 11 Feb 2021 14:14:18 +0100

This chapter explores plausible environmental effects on American well-being from a historical perceptive, using quantitative data and a methodological approach that draws from green economics. This adds an environmental dimension of welfare to Robert Gordon's interpretation of the development of well-being. First, it may be hypothesized that the levels of environmental damage rose especially during the prosperous decades following the World War II, including the spread of motor vehicles, diffusion of air traffic, and increased energy consumption. If so, the traditional way of measuring economic progress, i.e., gross domestic product, would exaggerate the true development of well-being. On the contrary, second, the true progress of the post-1970 period may have been underestimated if environmental damage actually decreased as a consequence of an environmental awakening among producers, consumers, and agents, creating modern environmental policy. However, as the cost of carbon is time dependent, we can foresee that the environmental costs will continue to increase.

Applicability of the Path Computation Element to Inter-area and Inter-AS MPLS and GMPLS Traffic Engineering

Scipedia content — Thu, 11 Feb 2021 14:11:50 +0100

The Path Computation Element (PCE) may be used for computing services that traverse multi-area and multi-AS Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineered (TE) networks. This document examines the applicability of the PCE architecture, protocols, and protocol extensions for computing multi-area and multi- AS paths in MPLS and GMPLS networks.

Forecasting, visibility and 3D route optimization for future air traffic management

Scipedia content — Wed, 10 Feb 2021 09:18:31 +0100

Forecasting, visibility and 3D route optimization for future air traffic management

Scipedia content — Tue, 09 Feb 2021 09:34:22 +0100

A review of incentives and social determinants for the adoption of electric vehicles

Scipedia content — Tue, 09 Feb 2021 09:22:42 +0100

Treball Final de Grau en Economia. Codi: EC1049. Curs acadèmic: 2018-2019 This paper aims to review the incursion into the current market for electric vehicles focusing in the incentives and the social determinants that make these vehicles attractive to consumers. For this purpose, it is studied the technical determinants that tell us why this type of vehicle is suitability and the incentives for the population to acquire this vehicles. Also this work aims to review and analyse the initiatives carried out in the Spanish territory for the adoption of electric vehicles, through objective data and reports, and also compare them with the measures carried out in United States and China. It is also intended to review the existing articles on the social determinants in the adoption of electric vehicles to know which are the social reasons that make these vehicles attractive to potential consumers.

Forecasting, visibility and 3D route optimization for future air traffic management

Scipedia content — Tue, 09 Feb 2021 08:59:44 +0100

Comparative analysis between high-capacity road, Spain-Japan

Scipedia content — Tue, 09 Feb 2021 08:58:02 +0100

Study of air market between Italy and Spain

Scipedia content — Tue, 09 Feb 2021 08:57:24 +0100

The aim of this project is to analyze historic series of data, from 1990, about the air market between Italy and Spain, comparing these states and understanding what are common points and differences. The type of analysis has to be economical focusing on evolution of the market considering companies involved, territories and flights available. 750h. This project has been created with the aim of studying and comparing the air market between two countries: Italy and Spain. This study is based on the network analysis of the two countries analyzed, evaluating the internal passenger air traffic, going to define which variables influence the centrality of the airports. This thesis is divided into different parts. It opens with a brief historical introduction, being the aviation market very recent, it is given a vision of how it has evolved in a few years. The structure of the market is then illustrated, identifying the value chain, actors involved, and network structures that characterizes it. Having a complete vision of the problem, a preliminary analysis is carried out, thus presenting the global characteristics of the European air market, analyzing the position of Italy and Spain in relation to the transport of goods and passengers, thus identifying the first similarities and differences through a GDP analysis. A special focus is given on the analysis of air passengers traffic in the two countries, which is divided into: Intra-EU and Extra-EU, going to identify the position in the European market and the largest airports that manage a greater volume of passengers. We begin to enter the heart of the analysis by studying the network of Italy and Spain in 2007 and 2017, analyzing how the structure has changed over a period of 10 years. Following this, a multiple linear regression model is developed, whose objective is to evaluate which variables analyzed influence the centrality of the airports in the considered country. The validity of the different assumptions will then be tested on the model created. The paper concludes by summarizing what emerged from the analysis, illustrating limitations of the model and providing an overview of how the research can continue.

Supply Evaluation for Hybrid Electric Heavy-Duty Trucks through Overhead Lines

Scipedia content — Tue, 09 Feb 2021 08:53:39 +0100

This project is about the charging process by means of overhead lines in specific roads and highways that are dedicated to big electrical trucks. Those trucks can charge their batteries during their trip.

Optimizing Resource Usage in an Unobtrusive Way Through Smart Aggregation: The Case of Electric Vehicle Charging in Amsterdam

Scipedia content — Mon, 08 Feb 2021 12:36:17 +0100

The increasing popularity of electric vehicles (EVs) is known to amplify the already present peaks in electricity demand. The possibility to remotely control and influence the charging of many EVs using the Internet of Things (IoT) via an aggregator has been proposed to optimize resource usage, to alleviate peak problems, and to exploit revenues that may be harnessed from fluctuating electricity prices. However, so far, the potential hinged on the acceptance of users, particularly the willingness to change their charging behavior. In this study, we develop an unobtrusive and easily implementable optimization method. Its effectiveness is tested on 360,000 charging sessions at public charging points in Amsterdam during the year 2015, providing a realistic assessment of the effects of optimization in terms of reduced costs, change in peak demand, and long occupancy of charging points. Based on the model, an average reduction of electricity costs between 20% and 30% can be achieved, depending on the day of the week. We also show that changing EV owner’s charging preferences such as starting earlier or later can benefit certain groups of EV drivers substantially and reduce electricity charging costs up to 35%.

DENSE:Environment Perception in Bad Weather—First Results

Scipedia content — Mon, 08 Feb 2021 12:33:20 +0100

This paper presents the first results of the publicly funded ECSEL project DENSE (Adverse weather environmental sensing system). DENSE seeks to eliminate one of the most pressing problems of automated driving: the inability of current systems to sense their surroundings under all weather conditions. The task in DENSE is to develop a sensor suite for automatic driving, by means of which the vehicle environment can be reliably detected 24/7 under these bad weather conditions. In this paper, the state of the art of environmental sensor technology is first examined and evaluated in the CEREMA weather chamber. Then, the architecture of the DENSE Sensor Suite is presented and the development results of the most important system components are described. The results show that the realization of a 24/7 all-weather sensor suite is absolutely feasible with these components .

Optimizing Resource Usage in an Unobtrusive Way Through Smart Aggregation: The Case of Electric Vehicle Charging in Amsterdam

Scipedia content — Mon, 08 Feb 2021 12:25:36 +0100

Towards E-mobility: Strengths and Weaknesses of Electric Vehicles

Scipedia content — Mon, 08 Feb 2021 10:23:49 +0100

One of the greatest environmental challenges worldwide is mobility. In future, increasingly sustainable solutions will be proposed and incentivized and the new technologies, like electric mobility, could (positive) influence mobility performances/habits. The paper aims at critically analyze weaknesses, strengths and application fields of the electric mobility in Italy. Specifically, the electric vehicle today has high production costs, low autonomy and not “zero” environmental impacts deriving from the production, motion and recycling of the vehicle. However, the “local emissions” are null and this pone this technology useful for urban mobility, where high population density often occurs. Furthermore, e-mobility is useful within the new forms of mobility (e.g. MaaS - mobility as a service) where micro mobility, shared mobility, urban bus fleet, freight distribution and an overall higher willingness to pay for users/operators could emphasize the strengths of e-mobility, reducing its weaknesses.

Feeling-of-Safety Slider

Scipedia content — Mon, 08 Feb 2021 10:23:00 +0100

Can interactions between automated vehicles and pedestrians be evaluated in a quantifiable and standardized way? In order to answer this, we designed an input device in the form of a continuous slider that enables pedestrians to indicate their willingness to cross a road and their feeling of safety in real time in response to an approaching vehicle. In an initial field study, 71% of the participants reported that they were able to use the device naturally and indicate their feeling of safety satisfactorily. The feeling-of-safety slider can consequently be used to evaluate and benchmark interactions between pedestrians and vehicles, and compare communication interfaces for automated vehicles.

Geometric optimization Of Variable Flux Reluctance Machines For Full Electric Vehicles

Scipedia content — Mon, 08 Feb 2021 10:22:12 +0100

One of the crucial components for electric vehicles, the electric machine has been widely examined from the perspective of machine topology, torque and power density, material usage, and efficiency. In this study, a relatively novel type of electrical machines without permanent magnet material, namely the variable flux reluctance machine (VFRM) is optimized towards a high drive cycle efficiency. In particular, a 12-stator/l0-rotor pole (12/10) VFRM is designed to match the torque and power level of a BMW i3 electric motor. The aim of this design study is to verify whether or not the VFRM is a viable, low-cost alternative for the main traction motor. In addition, rotor skewing has been investigated to successfully reduce the torque ripple. Finally, several down-scaled versions of the VFRM design are analyzed using Finite Element simulations to determine their efficiency maps. These maps are then compared to linearly scaled efficiency maps of the original VFRM design. The results of this comparison show that the efficiency maps change shape and magnitude and are therefore not directly comparable.

Economic viability of smart charging EVs in the Dutch ancillary service markets

Scipedia content — Mon, 08 Feb 2021 10:19:58 +0100

Smart charging of electric vehicles (EVs) could potentially facilitate easing network imbalance and grid over-loading issues that are expected to emerge due to the increase in sustainable energy alternatives in the near future. It has been shown that smart charging is technically possible, however, if there are no positive business cases, it is unlikely to succeed. One of the possible business cases is supplying energy in ancillary services markets. This paper investigates this business case for the Dutch ancillary service markets by determining the investment and operational costs of smart charging a pool of EVs and creating a market participation model that combines EV charging data with market data to calculate the potential profit.

Feeling-of-safety slider: measuring pedestrian willingness to cross roads in field interactions with vehicles

Scipedia content — Mon, 08 Feb 2021 10:17:16 +0100

HRSG-pipeline weld residual-stress measurement to assess influence over creep-analysis results from Italian code, American standard

Scipedia content — Mon, 08 Feb 2021 10:14:21 +0100

"jats:p"Previous study carried out residual stress characterization for the welds of the high-temperature-section (superheater / reheater) lower headers of the bottom-supported heat-recovery steam generator (HRSG). Modeling the gas-tungsten arc, manual welding process considered only weld-lay for the ASTM A 335-Grade P22 finned-tube angle joint to the cylinder. Present study aims at indirectly assessing findings of previous analysis measuring maximum residual stress on the joint’s exservice material. To achieve that a tee similar to the previous was not available: for both experimental and numerical analyses present study considers a P22 circumferential “V”-groove butt joint on HRSG pipeline section, creep-operated for the same period and temperature as the previous case. In the experimental activity X-ray diffraction method (or alternatively, hole-drilling strain gage one) applies as close as possible to the weld, being residual stress maximum at the fusion boundary. Thermal analysis for the previous case also showed it keeps nearly constant during weld cooling, relaxing most during creep: after 200,000 hours of operation, welding-process simulation predicted a maximum residual stress of 70 MPa; tee-joint creep-analysis found out a maximum equivalent stress of 91 MPa. As for the sample withdrawal, dimensions should be sufficient to avoid any interference with measurement area. The experimental procedures should comply with the European standard EN 15305 on the matter (the American standard ASTM E 837 for the alternate method). Comparison of analysis results for the two cases, confirms tendencies previously found out in creep-behavior, though different equivalent stress contributions. Comparison of predicted and observed residual stress values should allow for validation of numerical models used in both welding process and stress analysis.

Wizards of WoZ: using controlled and field studies to evaluate AV-pedestrian interactions

Scipedia content — Mon, 08 Feb 2021 10:13:47 +0100

Interactions between autonomous vehicles (AV) and pedestrians remain an ongoing area of research within the AutoUI community and beyond. Given the challenge of conducting studies to understand and prototype these interactions, we propose a combined full-day workshop and tutorial on how to conduct field experiments and controlled experiments using Wizard-of-Oz (WoZ) protocols. We will discuss strengths and weaknesses of these approaches based on practical experiences and describe challenges we have faced. After diving into the intricacies of different experiment designs, we will encourage participants to engage in hands-on exercises that will explore new ways to answer future research questions.

A hybrid robust-stochastic approach for the day-ahead scheduling of an EV aggregator

Scipedia content — Mon, 08 Feb 2021 10:09:28 +0100

Electric Vehicles (EVs) are emerging among the Distributed Energy Resources (DERs) as a promising flexibility source. The small-scale of DERs still constitutes a barrier to their direct participation in electricity markets. Aggregators can exploit EV smart charging to lower the energy procurement cost in the day-ahead (DA) scheduling phase. This cost minimization should consider the uncertainty stemming from the availability of EVs, the DA and the imbalance market prices. To catch all these uncertainties, a novel approach combining robust optimization and stochastic programming is proposed to define the DA charging schedule for an EV fleet, considering the DA market prices and the possible imbalance realizations in real-time. This method is compared with a two-stage stochastic (TSS) programming approach and with the EV uncontrolled charging. Two weeks of data from the DA spot market in the Netherlands have been used for comparing the methods with different fleet sizes: 100, 200 and 400 EVs. The results show that the hybrid robust-stochastic method, while keeping approximately the same average DA energy cost, can estimate better than the TSS method the actual daily energy cost with reduced computational time.