Scipedia: Documents published in 2019

Willingness to pay for electric vehicles and vehicle-to-grid applications: a Nordic choice experiment

Scipedia content — Tue, 16 Feb 2021 13:39:07 +0100

We present the results from a choice experiment conducted across Denmark Finland, Iceland, Norway and Sweden focusing on electric vehicles and vehicle-to-grid technology. The survey involved the entire Nordic region and had >4000 respondents choosing between two versions of electric vehicles (some including vehicle-to-grid capability) as well as their preferred gasoline vehicle. We analyzed the data using a mixed logit model and present the willingness to pay for driving range, acceleration, recharging time, fuel source, and vehicle-to-grid capability. In addition, due to the cross-national nature of our data, we also present willingness-to-pay comparisons between the five Nordic countries. We find that certain attributes, like driving range and recharging time, are substantially higher than previous estimates, whereas others, like acceleration are lower. In addition, we find that some attributes vary across the five countries (such as driving range), whereas other attributes remain constant. Finally, we find that vehicle-to-grid capability, divorced of onerous contracts, is significantly positive, but only for some countries, whereas in other countries it has no value, implying greater education and awareness of vehicle-to-grid is necessary if it is to accelerate electric vehicle adoption.

Marketing issues for remanufactured products

Scipedia content — Tue, 16 Feb 2021 13:38:40 +0100

Remanufacturing is an industrial process whereby used products are restored to useful life. This special issue seeks to address marketing issues for remanufactured products and provide an in-depth understanding of their barriers, together with mitigating practices and future opportunities. The articles present and analyse opportunities to improve marketing approaches for remanufactured products through exploring various marketing strategies, consumer behaviours, pricing and branding decisions, and optimized green transportation. This editorial note summarizes the outcomes of the papers published under this special issue, in addition to discussions on various influencing factors on marketing issues for remanufactured products including marketing attributes, customer willingness, pricing practices and performance evaluation methods. The final conclusion shows that there is sufficient scope to explore various perspectives connected with the issues of marketing remanufactured products through different fields of application.

Contested visions and sociotechnical expectations of electric mobility and vehicle-to-grid innovation in five Nordic countries

Scipedia content — Tue, 16 Feb 2021 13:38:23 +0100

Based on original data derived from 257 expert respondents across Denmark, Finland, Iceland, Norway, and Sweden, we investigate the different expectations and visions associated with one form of low carbon transport, electric mobility, inclusive of vehicle-to-grid and vehicle-grid-integration configurations. Utilizing concepts from the sociology of expectation—notably rhetorical visions, ideographs, promise-requirement cycles, and enablers and selectors—we examine how future electric mobility is envisioned. A collection of eight visions is analyzed and then placed into a typology. Some visions see electric mobility as a harbinger of positive social change in terms of ubiquitous automobility or endless innovation, others warn of families literally stranded and freezing to death on mountains and a business landscape marred with insolvent and financially struggling firms. We conclude with insights about what such competing and contradictory visions mean for energy and climate policy as well as sustainability transitions.

The long-haul low-cost airline business model: A disruptive innovation perspective

Scipedia content — Tue, 16 Feb 2021 13:38:00 +0100

This paper analyzes the impact of the long-haul low-cost (LHLC) airline business model on the air transport industry from a disruptive innovation perspective. We argue that the LHLC business model is set to stay; it is bound to penetrate the mass market that has, to date, been occupied by incumbent network carriers. It will thus lead to significant strategic adaptations in the long-haul air travel market where incumbents are well advised to prepare their responses. We provide a set of strategic response options along the categories of avoiding, accepting and embracing the LHLC business model that can be used by incumbents to defend their competitive positioning in the long-haul air travel market. This paper provides guidelines for airline managers to (re)evaluate the strategies of their own organizations facing the emergence of a potentially disruptive innovation in their industry.

Navigating expert skepticism and consumer distrust: Rethinking the barriers to vehicle-to-grid (V2G) in the Nordic region

Scipedia content — Tue, 16 Feb 2021 13:37:21 +0100

Vehicle-to-grid (V2G) refers to a technology that could help make the electricity grid more effective, reduce the cost of ownership of electric vehicles (EVs), and help integrate intermittent renewable energy sources. However, despite these advantages, implementation and even knowledge of the technology is not widespread. In order to explore why, we ask the question: what are the barriers that V2G currently faces? To provide an answer, the authors conducted 227 semi-structured interviews with transportation and electricity experts from 201 institutions across seventeen cities within a market currently experimenting with electric mobility and V2G, the Nordic region. Results show that there is an extensive range of barriers facing V2G, with experts suggesting in total 35 categories of barriers. While the literature espouses substantial benefits of V2G, the experts interviewed generally displayed skepticism of the benefits and necessity of V2G in the Nordics. We categorized the top nine discussed barriers into four clusters. These clusters focused on the experts’ skepticism of the benefits of V2G, consumer acceptance, economic viability, and regulatory structure for V2G participation. We conclude the paper with policy implications and suggestions for future research.

A unified solid/fluid finite element formulation and its possibility for modelling submarine landslides and their consequences

Scipedia content — Tue, 16 Feb 2021 13:36:26 +0100

Consequences of submarine landslides include both their direct impact on offshore infrastructure, such as subsea electric cables and gas/oil pipelines, and their indirect impact via the generated tsunami. The simulation of submarine landslides and their consequences has been a long-standing challenge majorly due to the strong coupling among sliding sediments, seawater and infrastructure as well as the induced extreme material deformation during the complete process. In this paper, we propose a unified finite element formulation for solid and fluid dynamics based on a generalised Hellinger–Reissner variational principle so that the coupling of fluid and solid can be achieved naturally in a monolithic fashion. In order to tackle extreme deformation problems, the resulting formulation is implemented within the framework of the particle finite element method. The correctness and robustness of the proposed unified formulation for single-phase problems (e.g. fluid dynamics problems involving Newtonian/Non-Newtonian flows and solid dynamics problems) as well as for multi-phase problems (e.g. two-phase flows) are verified against benchmarks. Comparisons are carried out against numerical and analytical solutions or experimental data that are available in the literature. Last but not least, the possibility of the proposed approach for modelling submarine landslides and their consequences is demonstrated via a numerical experiment of an underwater slope stability problem. It is shown that the failure and post-failure processes of the underwater slope can be predicted in a single simulation with its direct threat to a nearby pipeline and indirect threat by generating tsunami being estimated as well. The authors wish to acknowledge the support of European Commission H2020 Marie Sklodowska-Curie actions individual fellowship (Reference 744281; Proposal title “Towards Submarine Landslides and Their Consequences”). Peer Reviewed

Document type: Article

Mapping of service deployment use cases and user requirements for an on-demand shared ride-hailing service: MOIA test service case study

Scipedia content — Tue, 16 Feb 2021 13:35:55 +0100

Demand Responsive Transportation (DRT) is currently growing in our cities as shared ride-hailing services operated by private companies, providing a hybrid service between the bus and the taxi. Like DRT, these new on-demand services could be used to feed and complement the public transport, and additionally, their flexibility might bring other market opportunities, beneficial to cities and metropolitan areas. However, the true potential of them, as well as the recognition of the service requirements depending on the type of user and use case, remains unstudied. Hence, the aim of this research is to identify user requirements and market opportunities, from the case study conducted with the participation of 1211 users of the MOIA service test in Hanover, to contribute to the successful design of this new generation of DRT. Results indicate a high interest in using MOIA for leisure trips, identify the highest intention of use of the service within suburban areas, and recognise a different behaviour, both in the intention of use and for user requirements, depending on the age of the users and the usage frequency.

Peer Reviewed

Vehicle fleet characterization study in the city of Madrid and its application as a support tool in urban transport and air quality policy development

Scipedia content — Tue, 16 Feb 2021 13:35:41 +0100

Road transport is one of the main sources of atmospheric emissions especially in urban areas where exceedances of NO2 or PM limit values are common. This has evident implications regarding health effects and justifies the need to design and apply effective measures to reduce emissions from mobile sources in urban areas. The methodologies to estimate emissions from road transport require, among other relevant factors, a detailed characterization of the actual fleet composition within the city that vehicle registration databases cannot provide. This contribution presents an experimental campaign to characterise the fleet of vehicles moving in the city of Madrid (Spain). The field campaign made use of different types of already available traffic cameras in the city to record nearly 5 million license plate readings from 1.3 million different vehicles. This information was used to estimate emissions with the COPERT model in the area of study. According to results obtained, passenger cars are responsible for 80.7% of the total mileage made in the city and are also the main contributors in terms of emissions (65%, 73% and 72% of NOx, CO2 and PM2.5, within mobile sources respectively), mainly due to diesel vehicles that represent 68.2% of total passenger cars mileage. The study also provided relevant information on average age and other policy-relevant details such as average emission factors that should be considered to propose effective emission abatement strategies in Madrid City. A comparison with the information obtained from official registration statistics illustrates the need to perform similar studies to gather accurate information of the actual fleet within a city and thus, design sound measures and policies.

Wearable sensors for evaluating driver drowsiness and high stress

Scipedia content — Tue, 16 Feb 2021 13:35:25 +0100

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

FLOR will redefine the paradigms under which remote pilots and Remotely Piloted Aircraft Systems have been designed and operated during the last decades; i.e. a dedicated crew manages a single aircraft, indistinctive from being the latter manned or unmanned. Most of the existing and ongoing investigations related to the insertion of RPAS into air traffic have addressed the impact of operating a single aircraft. However, it has never been considered the advantatges of operating of a fleet of RPAS managed within a dedicated ground facility involving a specialised team of remote pilots. Currently, only the military applies RPAS in a large scale, and although in that specific environment the pressure to reduce operational costs is increasingly high, nevertheless the armed services do not have to face the pressure of an open market. FLOR intends to investigate the requirements for a new generation of RPAS systems that support a revolutionary operational paradigm: each pilot operates multiple RPAS in a certain phase of flight; pilots transfer the flight responsavility as the RPAS operation progresses. FLOR improves the way in which RPAS operators employ both aircraft and remote pilots, especially in terms of economic efficiency and safety. The improvements will come from multiple sources, such as a better exploitation of the vehicle availability as it will not be limited to the capabilities or duty time of a single crew. Further improvements are a more advantageous use of personnel resources. Each individual can be allocated to a certain tasks that better fit his competences and capabilities and those tasks may be adjusted dynamically over time. Pilots may supervise multiple RPAs during the extensive and uneventful cruise portions of flights, while may focus on individual vehicles to manage the critical parts of the flight, or to respond to emergency/abnormal situations. The ground based flight control of the aircraft fleet is improved by centralizing the RPAS piloting in a small network of highly capable infrastructures which will guarantee the desired levels of certification, fault-tolerance, and service continuity. Finally, from a safety perspective, the possibility of transferring the control of the RPAS for a change of pilot or to another piloting centre in case of need, will allow an unprecedented extra safety measure. The FLOR concept will prove effective for extensive commercial point-to-point cargo operations, but also when conducting surveillance operations, e.g. disaster monitoring with a fleet of MALE/HALE RPAS or operating a fleet of solar powered RPAS slowly loitering at extremely high altitude. This issue is often addressed as some of the most feasible deployment of RPAS, as those operations might be dangerous or exhausting for pilots in manned aircraft. Within the most recent European Commissions update of the Aviation Strategy for Europe the huge potential of drones in the sense of unmanned aircraft systems (UAS) is highlighted. EC is asking for R&D in reducing risks associated to UAS. In addition EC sees the need for improving related technologies and operations to unleash their full market potential. FLOR paves the way for the efficient application of UAS operated as RPAS with respect to their fleet management and control.

Peer Reviewed

Analysis of crater formation in buried NG pipelines: A survey based on past accidents and evaluation of domino effect

Scipedia content — Tue, 16 Feb 2021 13:35:06 +0100

The formation of a crater by the abrupt and catastrophic rupture of a high-pressure pipeline can be highly relevant, especially when the crater uncovers other pipelines, which could undergo a domino effect with a significant increase of the consequences on people or on the environment. However, this scenario has been only partially studied in the literature. To assess the influence of the pipeline parameters on the dimensions of the resulting crater, a statistical analysis of accidental ruptures of buried natural gas pipelines that have involved the formation of a crater was carried out. Mathematical expressions are proposed to describe the proportionality relationships found, which can be very useful to support adequate separation distances in the design and construction of parallel corridors of pipelines after appropriate escalating effects are considered. Finally, detailed event trees were developed to calculate the probability of occurrence of the final outcomes, as well as the identified domino sequences, based on a qualitative and quantitative analysis of the data. The study of these accident scenarios, based on actual cases, represents a useful and needed advance in risk analysis of natural gas transportation through pipelines.

Comprehensive high speed automotive SM-PMSM torque control stability analysis including novel control approach

Scipedia content — Tue, 16 Feb 2021 13:34:52 +0100

Permanent magnet synchronous machines (PMSM) are widely used in the automotive industry for electric vehicle (EV) and hybrid electric vehicle (HEV) propulsion systems, where the trend is to achieve high mechanical speeds. High speeds inevitably imply high current electrical frequencies, which can lead to a lack of controllability when using field oriented control (FOC) due to sampling period constraints. In this work, a comprehensive discrete-time model is fully developed to assess the stability issues in the widely used FOC. A speed-adaptive control structure that overcomes these stability problems and extends the speed operation range of the PMSM is presented. Also, a numerical methodology from which the maximum operating stable frequency can be computed in advance of any experimentation, is developed. All contributions are accompanied and supported by numerical results obtained from an accurate MATLAB/Simulink model.

Peer Reviewed

A multi-control vehicle-to-grid charger with bi-directional active and reactive power capabilities for power grid support

Scipedia content — Tue, 16 Feb 2021 13:34:21 +0100

This paper proposes a multi-control vehicle-to-grid charger with bi-directional power capability. The proposed charger can perform vehicle battery charging and discharging operations, as well as power grid support such as reactive power compensation, power factor correction, and grid voltage regulation. The performances of the charger controls were examined under various power grid scenarios. Results revealed that the vehicle-to-grid charger attained the highest charger efficiency when operating at unity power factor mode. Nevertheless, vehicle charging at unity power factor introduced a significant grid voltage drop which may violate the grid voltage limits. This problem was solved by using the voltage control, which injected reactive power to the power grid for accurate voltage regulation. This paper also proposed an autonomous multi-control selection algorithm to intelligently switch between the multiple charger controls in response to the power grid condition. Results showed that the proposed algorithm effectively instructed the charger to work in efficient control modes if the grid voltage was within the permissible voltage limits. Whenever the grid voltage exceeded the limits, the charger automatically switched to grid voltage control for power grid voltage regulation.

Conspicuous diffusion:Theorizing how status drives innovation in electric mobility

Scipedia content — Tue, 16 Feb 2021 13:34:07 +0100

This paper explores how conceptions of luxury and status affect the manner in which a relatively novel technology—an electric vehicle— diffuses across societies. To do so, it combines Veblen’s notion of conspicuous consumption and Roger’s diffusion of innovation by proposing a new theoretical variation, which we term “conspicuous diffusion.” The paper sketches natural connections between the two theories, namely how conspicuous consumption relates to technological and societal development, and how diffusion of innovation is intrinsically connected to status. In combining these approaches, we hypothesize that the success of an innovation is guided by its adherence to the canons of conspicuousness and conspicuous value, which it loses as the innovation diffuses across the population. To illustrate the explanatory power of conspicuous diffusion, we examine the status of electric vehicles in the Nordic region, based on original data from multiple methods, including expert interviews and focus groups. We find that conspicuous diffusion can explain previous failures and current successes of electric vehicle diffusion patterns. The paper concludes with recommendations for policymakers, industry, and academia.

Model predictive control and moving horizon estimation for water level regulation in inland waterways

Scipedia content — Tue, 16 Feb 2021 13:33:30 +0100

This work regards the design of optimization techniques for the purposes of state estimation and control in the framework of inland waterways, often characterized by negligible bottom slopes and large time delays. The derived control-oriented model allows these issues to be handled in a suitable manner. Then, the analogous moving horizon estimation and model predictive control techniques are applied in a centralized manner to estimate the unmeasurable states and fulfill the operational goals, respectively. Finally, the performance of the methodology is tested in simulation by means of a realistic case study based on part of the inland waterways in the north of France. The results show that the proposed methodology is able to guarantee the navigability condition, as well as the other operational goals.

This work has been partially funded by the Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the projects DEOCS (ref. MINECO DPI2016-76493) and SCAV (ref. MINECO DPI2017-88403-R). This work has also been partially funded by AGAUR of Generalitat de Catalunya through the Advanced Control Systems (SAC) group grant (2017 SGR 482).

Deformation and fracture of cylindrical tubes under detonation loading : A review of numerical and experimental analyses

Scipedia content — Tue, 16 Feb 2021 13:33:14 +0100

The dynamic load in tubes due to detonation has a number of applications, such as in oil pipeline systems and pulse detonation engines. Various experimental, analytical, and numerical investigations have been conducted to study the mechanical, thermo-mechanical, and fracture behavior of tubes under internal detonation loads. Regarding numerical analysis, different approaches such as interface cohesive element, mesh-free, and extended finite element methods have been used to model the propagation of crack(s) in a tube. This paper presents a review of relevant literature pertaining to numerical and experimental analyses of detonation-driven deformation and fracture, and of studies based on the analytical investigation of moving loads in detonation tubes. The corresponding findings are discussed in detail, and possible avenues for future research are highlighted. Peer reviewed

Laboratory tests and discrete element simulations

Scipedia content — Tue, 16 Feb 2021 13:21:45 +0100

To mitigate the ballast flight risk in the high-speed railway, this paper presents three new polyurethane bonding schemes which have negligible influence to tamping operations. With the application of these bonding schemes, a series of laboratory tests indicated that the polyurethane-reinforced ballast exhibited much larger lateral resistance than the ordinary ballast by 31% at least. Discrete element simulation results further demonstrated that the polyurethane improved the load-bearing capacity of the ballast at the particle scale through effectively restraining the particle movement. Therefore, the proposed bonding schemes ensure adequate lateral ballast resistance and are effective measures for improving the ballast performance.

Distributed Reactive Model Predictive Control for Collision Avoidance of Unmanned Aerial Vehicles in Civil Airspace

Scipedia content — Tue, 16 Feb 2021 13:19:03 +0100

Safety in the operations of UAVs (Unmanned Aerial Vehicles) depends on the current and future reduction of technical barriers and on the improvements related to their autonomous capabilities. Since the early stages, aviation has been based on pilots and Air Traffic Controllers that take decisions to make aircraft follow their routes while avoiding collisions. RPA (Remotely Piloted Aircraft) can still involve pilots as they are UAVs controlled from ground, but need the definition of common rules, of a dedicated Traffic Controller and exit strategies in the case of lack of communication between the Ground Control Station and the aircraft. On the other hand, completely autonomous aircraft are currently banned from civil airspace, but researchers and engineers are spending great effort in developing methodologies and technologies to increase the reliability of fully autonomous flight in view of a safe and efficient integration of UAVs in the civil airspace. This paper deals with the design of a collision avoidance system based on a Distributed Model Predictive Controller (DMPC) for trajectory tracking, where anticollision constraints are defined in accordance with the Right of Way rules, as prescribed by the International Civil Aviation Organization (ICAO) for human piloted flights. To reduce the computational burden, the DMPC is formulated as a Mixed Integer Quadratic Programming optimization problem. Simulation results are shown to prove the effectiveness of the approach, also in the presence of a densely populated airspace.

The impact of tribology on energy use and CO"sub"2"/sub" emission globally and in combustion engine and electric cars

Scipedia content — Tue, 16 Feb 2021 13:18:43 +0100

Growing concerns over energy and environmental sustainability have lately sparked worldwide interest in more efficient and cleaner transportation systems and industrial activities. Friction roughly consumes one-fifth of all energy used worldwide. One-third of all energy used in transportation goes to overcome friction. At the same time, the fruits of decades of dedicated research on all-electric vehicles powered by advanced batteries are paving the way toward a much cleaner and sustainable transportation future. In this article, we provide a short overview of what are the energy efficiency and environmental impacts of current transportation, industrial, and residential systems and how much of that efficiency is adversely affected by friction and wear losses in moving mechanical parts and components. We also touch upon recent advances in new materials, lubricants, and design changes that could reduce energy losses by 18–40%, mainly resulting from friction and wear. The savings would be up to 8.7% of the total global energy use and 1.4% of the gross national products (GNP). Finally, we calculate the energy consumption and friction losses in battery-powered electric passenger cars and show the benefit of electric cars where the total energy use is in average 3.4 times lower compared to combustion engine powered cars. The CO"sub"2"/sub" emissions are 4.5 times higher for a combustion engine car compared to an electric car when the electricity comes from renewable energy sources. Moving from fossil to renewable energy sources may cut down the energy losses due to friction in energy production by more than 60%.

Methodology of Power Distribution System Design for Hybrid Short Sea Shipping

Scipedia content — Tue, 16 Feb 2021 13:17:46 +0100

lication of energy storage (ES) in power distribution systems (PDS) of short sea shipping marine vessels is gaining ground. The main drivers are the increasing demand for higher energy efficiency and the decreasing costs of battery ES systems (BESS). The feasible chemistry and dimensioning of the BESS depend heavily on the vessel type, the PDS topology, and the load profile. Thus, no general rules for battery dimensioning that would fit all vessels can be presented, but the analysis must be performed by using an advanced modeling approach, which takes into account the abovementioned factors. This paper presents a modeling methodology for dimensioning marine vessel ES and hybrid PDS components. The methodology has been tested for two distinct vessels, a cruiseferry and an off-shore support vessel. Post-print / Final draf

Decentralized and discretized control for storage systems offering primary frequency control

Scipedia content — Tue, 16 Feb 2021 13:16:31 +0100

The provision of ancillary services is an additional revenue stream for the owners of inverter-equipped storage systems, such as batteries and electric vehicles. As real demonstrations have shown, primary frequency control (PFC) is a suitable and economically viable service for small-scale energy storage (ES) systems. This paper proposes a decentralized stochastic control policy, which significantly reduces ES units’ losses when providing PFC. The proposed controller can be tuned to obtain the desired service reserve provision errors, while achieving a balance between tracking accuracy and efficiency. An extension of the algorithm significantly reduces the switching rate of the devices by up to 95%. Analytical expressions for the reserve errors and the switching rates, dependent on the aggregation size and the controllers’ settings, are derived and verified by simulations. Simulation results show that the proposed controller can significantly reduce ES units’ losses when they are providing PFC by 8–15.5%, while achieving the expected tracking performance.

Long-term memory-induced synchronisation can impair collective performance in congested systems

Scipedia content — Tue, 16 Feb 2021 13:12:31 +0100

We investigate the hypothesis that long-term memory in populations of agents can lead to counterproductive emergent properties at the system level. Our investigation is framed in the context of a discrete, one-dimensional road-traffic congestion model: we investigate the influence of simple cognition in a population of rational commuter agents that use memory to optimise their departure time, taking into account congestion delays on previous trips. Our results differ from the well-known minority game in that crowded slots do not carry any explicit penalty. We use Markov chain analysis to uncover fundamental properties of this model and then use the gained insight as a benchmark. Then, using Monte Carlo simulations, we study two scenarios: one in which "myopicâ€ agents only remember the outcome (delay) of their latest commute, and one in which their memory is practically infinite. We show that there exists a trade-off, whereby myopic memory reduces congestion but increases uncertainty, while infinite memory does the opposite. We evaluate the performance against the optimal distribution of departure times (i.e. where both delay and uncertainty are minimised simultaneously). This optimal but unstable distribution is identified using a genetic algorithm. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.

Trip Centrality: walking on a temporal multiplex with non-instantaneous link travel time

Scipedia content — Tue, 16 Feb 2021 13:11:29 +0100

In complex networks, centrality metrics quantify the connectivity of nodes and identify the most important ones in the transmission of signals. In many real world networks, especially in transportation systems, links are dynamic, i.e. their presence depends on time, and travelling between two nodes requires a non-vanishing time. Additionally, many networks are structured on several layers, representing, e.g., different transportation modes or service providers. Temporal generalisations of centrality metrics based on walk-counting, like Katz centrality, exist, however they do not account for non-zero link travel times and for the multiplex structure. We propose a generalisation of Katz centrality, termed Trip Centrality, counting only the walks that can be travelled according to the network temporal structure, i.e. “trips”, while also differentiating the contributions of inter- and intra-layer walks to centrality. We show an application to the US air transport system, specifically computing airports’ centrality losses due to delays in the flight network.

Document type: Article

The Shape of Things to Come

Scipedia content — Tue, 16 Feb 2021 13:09:45 +0100

Much of our knowledge of the course of animal and plant evolution is based on shape. Recognition, description, arrangement, rearrangement, organization, reorganization, and interpretation of shape are the prime working tools of the paleontologist, the life blood of the systematist, the raw material of the evolutionist, and the dilemma of the developmental biologist. Keith Thomson's book, Morphogenesis and Evolution, deals with how shape changes both in ontogeny and in phylogeny. Morphogenesis is the study of the development of shape over an individual lifetime; evolution includes changes in shape throughout phylogeny. The development of form has been treated as a separate discipline since the German Naturphilosophie of Oken (1779-1851) and His (183 1-1904) and has been linked to phylogeny since von Baer (1792-1876). For Darwin, morphology was the soul of natural history (Darwin, 1910 p. 358), development and embryology, "one of the most important subjects in the whole round of natural history" (Darwin, 1910 p. 363). Mayr (1982 p. 468) believes that "evolutionary morphology" did not arise until the 1950's, with the distinction between function and role and the exploration of preadaptation, multiple functions, and multiple pathways. An integrated treatment of"morphogenesis and evolution" or, better, of morphogenesis as an evolutionary process therefore addresses, or should address, key questions in development, in evolution, and in the consequences of the one for the other. In developmental biology, and certainly in general treatises on animal development (of which the second edition of Scott Gilbert's [19881 Developmental Biology is the best currently available), morphogenesis is normally treated alongside differentiation (specialization of the parts of the embryo). This is not because morphogenesis and differentiation always proceed handin-hand, for even when they occur contemporaneously in space and time, each may be under separate and independent developmental control (see Maclean and Hall, 1987), but because the two, along with growth, constitute the triad of developmental processes. Morphogenesis normally occurs alongside cellular differentiation in growing tissues or organs. Differentiating cells often change shape as they grow (either by

Analytical and numerical solutions

Scipedia content — Tue, 16 Feb 2021 13:09:25 +0100

The motion of liquid filling a pipeline is impeded when the gas ahead of it cannot escape. Entrapped gas will lead to a significant pressure build-up in front of the liquid column, which slows down the column and eventually bounces it back. The pressure and temperature in the gas may become dangerously high, and for example, lead to fires and explosions caused by auto-ignition. This paper considers the case where the trapped gas can escape through a vent. One new element is that the pressure head of the liquid supply reservoir is fluctuating instead of staying constant. The obtained analytical and numerical solutions are utilized in parameter variation studies that give deeper insight in the system's behavior.

Intelligent control of high energy efficient two-stage battery charger topology for electric vehicles

Scipedia content — Tue, 16 Feb 2021 13:09:11 +0100

Turksoy, Omer/0000-0003-4620-4503

WOS: 000492797300026

The energy efficiency of the battery charging system directly affects the distance which electric vehicles can get with per charge process. In addition, reducing current harmonics distortion (THD) increases the electrical quality and power conversion performance. This paper proposes intelligent control of high-efficiency two-stage battery charger topology for electric vehicles (EVs). In the first stage, for low harmonics of input current, high power factor and high efficiency, the average current mode controlled ac/dc boost power factor (pf) correction method constructed and analyzed with 98% efficiency and the power factor is achieved higher than 0.99. Additionally, in the second stage, for high energy efficiency, higher battery lifespan and allowing EVs to get more miles with per charge, a half-bridge LLC resonant converter controlled with a designed artificial neural network (ANN). Moreover, the LLC resonant converter controlled under dynamic load to analysis system from no-load to full-load. A 3.1 kW powered system has been designed for this study, the efficiency of the system has been calculated based on European efficiency standards and the peak efficiency of the whole system is 96.2%, the load voltage ripple is less than 0.5 V and also total harmonic distortion of the source current is less than 5%. (C) 2019 Elsevier Ltd. All rights reserved.

Improving a battery charger architecture for electric vehicles with photovoltaic system

Scipedia content — Tue, 16 Feb 2021 13:06:16 +0100

WOS: 000513381900001

In this study, a two-stage battery charger architecture with high-efficiency, multi-input, and output half-bridge LLC (HBLLC) resonance converter that performs a wide load range is proposed. The first input of the HBLLC is provided by the photovoltaic (PV) panel assembly on the vehicle. A high efficiency and fast maximum power point tracking (MPPT) algorithm has been developed for the PV panel to operate at the maximum power point. The other input is supplied by a grid-connected AC-DC bridgeless power factor correction (PFC) converter, which is controlled with the average current mode (ACM) control method. The most important feature that distinguishes the designed topology from previous studies is that it charges the low-voltage battery through the PV panel. In previous studies, the low-voltage battery was being charged via the high-voltage battery. This allowed the high-voltage battery to transfer power to the low-voltage battery even when it was not charged. However, in the proposed architecture, the low-voltage battery is fed by a PV panel. This condition allows the electric vehicle to take more miles with a single charge process. Furthermore, the proposed architecture reduces energy costs in the long term by providing some of the energy demanded from the grid. In addition, the proposed integrated battery charging circuit is intended to reduce the cost of additional cables. The system is designed as 3.1 kW power and operated under no load to full load. As for the performance of the proposed architecture, the peak efficiency of the LLC resonant converter is 95.3%. In addition, peak efficiency of the AC-DC bridgeless PFC converter is 97.3%, while the power factor is higher than 0.99, input current total harmonic distortion (THD) is less than 5%, MPPT method accuracy is higher than 99%, and output voltage ripples (Delta V) is less than 1 V.

A graph CNN-LSTM neural network for short and long-term traffic forecasting based on trajectory data

Scipedia content — Tue, 16 Feb 2021 12:55:19 +0100

Traffic forecasting is an important research area in Intelligent Transportation Systems that is focused on anticipating traffic in order to mitigate congestion. In this work we propose a deep neural network that simultaneously extracts the spatial features of traffic, using graph convolution, and its temporal features by means of Long Short Term Memory (LSTM) cells to make both short-term and long-term predictions. The model is trained and tested using sparse trajectory (GPS) data coming from the ride-hailing service of DiDi in the cities of Xi'an and Chengdu in China. Besides, presenting the deep neural network, we also propose a data-reduction technique based on temporal correlation to select the most relevant road links to be used as input. Combining the suggested approaches, our model obtains better results compared to high-performance algorithms for traffic forecasting, such as LSTM or the algorithms presented in the TRANSFOR19 forecasting competition. The model is capable of maintaining its performance over different time-horizons from 5 min to up to 4 h with multi-step predictions.

Tentative governing of fuel cell innovation in a dynamic network of expectations

Scipedia content — Tue, 16 Feb 2021 12:54:55 +0100

Expectations and visions are known to be forceful elements in the governance of emerging innovations. However, visions and expectations are prone to change, thus creating challenges for strategy and policy processes. Actors have to deal with the dynamics of expectations, either ex-post when expectations have changed, or ex-ante, for instance by taking possible future changes into account in the design of policy measures. This article follows the dynamics of fuel cell expectations in the German policy discourse (1994–2011). Firstly, we study how fuel cell expectations were discursively related to a wider network of expectations regarding developments in the context of fuel cells. Secondly, we examine whether and how policy measures referred to these expectations, and how policy dealt with the dynamic evolution of expectations. We show that fuel cell expectations alone were not sufficient to trigger substantial policy support; only once they linked up with visions and expectations about the future energy system and further context developments were supportive policy measures initiated. Furthermore, although we observed dedicated and successful efforts to stabilize policy support for fuel cells pre-empting possible changes in expectations, governance still had to adapt to changes in the network of expectations, in particular the rise in expectations for battery-electric vehicles.

Household travel mode choice estimation with large-scale data—an empirical analysis based on mobility data in Milan

Scipedia content — Tue, 16 Feb 2021 12:47:16 +0100

Data analysis plays a key role in supporting the development of sustainable transportation. Using the large-scale household mobility survey data collected in Milan, Italy during 2005–2006, we study whether the large-scale data contribute to improving accuracy in estimating household travel modes. This paper presents three machine learning methods including multinomial logit (MNL) model, random forest (RF) and support vector machine (SVM) to estimate the household travel mode. Their model accuracies are 70.41%, 71.89%, 72.74% respectively under the full sample size. It is found that the accuracies of these three methods fluctuate fiercely when the sample size is less than 20,000 and then stabilize gradually with continuous increasing it. After stabilization occurs, accuracies with these three methods do not significantly increase as the sample size continues to increase. We also study the travel characteristics derived from the large-scale survey data, which is fundamental for developing a sustainable transportation system. The collected data items include five explanatory variables, i.e., household size (HS), vehicle ownership, household income (HI), travel distance, travel time and one response variable (i.e., household travel mode), which includes public transport (PT), private car, usage of PT and private car simultaneously and the others travel modes (e.g., walk). We further investigate the importance of explanatory variables in terms of estimating household travel mode choice with the MNL model. It is found that vehicle ownership is the most critical factor influencing household travel mode choice, followed by travel distance, travel time, HS and HI. The ranking result is consistent with the RF approach.

Impact of solar field design and back-up technology on dynamic performance of a solar hybrid heating network integrated with a seasonal borehole thermal energy storage serving a small-scale residential district including plug-in electric vehicles

Scipedia content — Tue, 16 Feb 2021 12:46:56 +0100

A solar hybrid district heating network integrated with a seasonal borehole thermal energy storage is dynamically simulated and analyzed over a 5-year period. The system is devoted to satisfying the space heating and domestic hot water requirements of a small-scale district consisting of 6 typical Italian single-family houses, located in Naples, with home charging of 6 plug-in electric vehicles. Eight different plant schemes differing in terms of solar field configuration and/or back-up system used for compensating the intermittency of solar source are investigated. Two different configurations of solar field are analyzed: the first one with solar thermal collectors only and the second one integrating solar thermal collectors and photovoltaic panels coupled with a battery storage; three different alternative auxiliary units are considered: natural gas-fired boiler, natural gas-fueled internal combustion engine-based micro-cogeneration unit and wood pellet boiler. An additional operating scheme is also proposed to better exploit the solar energy for domestic hot water production. The primary energy consumption, the carbon dioxide emissions and the operating costs of the proposed plant configurations are evaluated based on simulation results and then compared with those associated to a conventional decentralized heating system in order to assess the main energy, environmental and economic benefits/drawbacks.

The effects of monitoring requests on driver attention, take-over performance, and acceptance

Scipedia content — Tue, 16 Feb 2021 12:42:17 +0100

In conditionally automated driving, drivers do not have to monitor the road, whereas in partially automated driving, drivers have to monitor the road permanently. We evaluated a dynamic allocation of monitoring tasks to human and automation by providing a monitoring request (MR) before a possible take-over request (TOR), with the aim to better prepare drivers to take over safely and efficiently. In a simulator-based study, an MR + TOR condition was compared with a TOR-only condition using a within-subject design with 41 participants. In the MR + TOR condition, an MR was triggered 12 s before a zebra crossing, and a TOR was provided 7 s after the MR onset if pedestrians crossing the road were detected. In the TOR-only condition, a TOR was provided 5 s before the vehicle would collide with a pedestrian if the participant did not intervene. Participants were instructed to perform a self-paced visual-motor non-driving task during automated driving. Eye tracking results showed that participants in the MR + TOR condition responded to the MR by looking at the driving environment. They also exhibited better take-over performance, with a shorter response time to the TOR and a longer minimum time to collision as compared to the TOR-only condition. Subjective evaluations also showed advantages of the MR: participants reported lower workload, higher acceptance, and higher trust in the MR + TOR condition as compared to the TOR-only condition. Participants’ reliance on automation was tested in a third drive (MR-only condition), where automation failed to provide a TOR after an MR. The MR-only condition resulted in later responses (and errors of omission) as compared to the MR + TOR condition. It is concluded that MRs have the potential to increase safety and acceptance of automated driving as compared to systems that provide only TORs. Drivers’ trust calibration and reliance on automation need further investigation. © 2019 Elsevier Ltd

Decommissioning of deep and ultra-deep water oil and gas pipelines: issues and challenges

Scipedia content — Tue, 16 Feb 2021 12:40:46 +0100

When production facilities reach the end of their economic life in the offshore oil and gas industry, field owners must decide whether to replace, extend the life of, or decommission assets. The decommissioning of deep and ultra-deep water oil and gas pipelines has become a serious issue in recent years because it is a complex process and presents challenges to stakeholders. In this paper, we review the current practices of pipeline decommissioning in different regions of the world and then highlight issues and challenges related to such activities in deep and ultra-deep waters. These issues and challenges can be broadly categorised into technical (e.g., selection of appropriate decommissioning procedures for handling hazardous pipelines), financial or economic, health and safety legislation, environmental, and human or organisational issues (such as lack of requisite skills, knowledge and expertise). In order to address the challenges identified in the study, some directions for future research are suggested. [Received: December 7, 2016; Accepted: October 17, 2017]

Coordinated delivery in urban retail

Scipedia content — Tue, 16 Feb 2021 12:39:13 +0100

In the Coordinated Delivery Problem (CDP), we study the passive and proactive coordination strategies that coordinate the delivery among urban retail stores. We formulate the CDP as mixed integer programs and develop a matheuristic, the effectiveness of which is evaluated via newly generated instances. Our numerical study shows that, when the stores prefer placing orders based on their own inventory policies, the proactive coordination strategy is able to achieve similar logistics and services performances to Vendor Managed Inventory (VMI), while respecting the store order decisions as under Retailer Managed Inventory (RMI), and thus offers an excellent combination of VMI and RMI.

Risk-involved participation of electric vehicle aggregator in energy markets with robust decision-making approach

Scipedia content — Tue, 16 Feb 2021 12:35:07 +0100

Uncertainty of different parameters in power systems can put market players at risk. For example, uncertainty of market prices in energy markets with capitalist characteristics can negatively affect decisions of aggregators participating in such markets to make profits. In fact, uncertainty in capitalist energy markets should be controlled since many individuals who participate in such markets have specific expectations (economic goals in most cases) and this may result in some concerns over the future performances of mentioned markets under uncertainty. It should be noted that aggregator can be a person or an authority who is responsible for a group of energy consumers/resources like electric vehicles (EVs) and seeks to participate in energy markets in order to get to some expected goals that can be economical, technical and etc. Moreover, attitude to risk of a decision-maker can change in different working conditions which needs to be considered through various decision-making criteria. In this paper, robust performance (optimal/stable operation against the worst possible condition of uncertainty) of an EV aggregator against the uncertainty of market price is studied by incorporating robust optimization method. The aggregator willing to participate in energy market can benefit from the provided strategies created by this optimization model to satisfy the expected economic goals and control the uncertainty of energy market. In detail, specific plans and strategies are determined toward possible values of uncertain market price that satisfy economic goals of aggregator and keep the uncertainty under control. Mixed integer non-linear programming (MINLP) is used to model the problem which is solved in general algebraic modeling system (GAMS) software. A microgrid system composed of distributed generation units (local generation units that can be either renewable or non-renewable) including dispatchable and non-dispatchable ones, EVs and storage system is studied, and the results are presented. The results show that robust optimization model can minimize the daily market cost while mitigating possible risks for the aggregator of EVs. It should be noted that daily market accounts for energy market in which various energy resources are available to be selected by the related aggregator in order to supply energy demand.

A human factors perspective on automated driving

Scipedia content — Tue, 16 Feb 2021 12:26:52 +0100

utomated driving can fundamentally change road transportation and improve quality of life. However, at present, the role of humans in automated vehicles (AVs) is not clearly established. Interviews were conducted in April and May 2015 with twelve expert researchers in the field of Human Factors (HF) of automated driving to identify commonalities and distinctive perspectives regarding HF challenges in the development of AVs. The experts indicated that an AV up to SAE Level 4 should inform its driver about the AV’s capabilities and operational status, and ensure safety while changing between automated and manual modes. HF research should particularly address interactions between AVs, human drivers, and vulnerable road users. Additionally, driver training programs may have to be modified to ensure that humans are capable of using AVs. Finally, a reflection on the interviews is provided, showing discordance between the interviewees’ statements—which appear to be in line with a long history of human factors research—and the rapid development of automation technology. We expect our perspective to be instrumental for stakeholders involved in AV development and instructive to other parties.

A knowledge-based framework for two-dimensional (2D) asymmetrical polygonal ship domain

Scipedia content — Tue, 16 Feb 2021 12:24:03 +0100

fiskin, remzi/0000-0002-5949-0193; NASIBOGLU, EFENDI/0000-0002-7273-1473

WOS: 000528188300004

Ship domain is crucial for traffic risk assessment and safe navigation at sea especially in high-density traffic. This study proposes a fuzzy rule-based model to create an asymmetrical polygonal ship domain for both restricted waters and open waters. the model takes into consideration various navigational factors which are determined as a result of expert interviews. A C# application based on fuzzy inference system (FIS) with Mamdani model has been implemented to create the size and shape of the domain. Finally, a few experimental tests and comparative implementations with other ship domains have been conducted to demonstrate the performance of the proposed system. the proposed ship domain will undoubtedly contribute to the ship traffic engineering and is considerably utilized in collision risk assessment and traffic design.

A Contextual GMM-HMM Smart Fiber Optic Surveillance System for Pipeline Integrity Threat Detection

Scipedia content — Tue, 16 Feb 2021 12:23:46 +0100

This paper presents a novel pipeline integrity surveillance system aimed to the detection and classification of threats in the vicinity of a long gas pipeline. The sensing system is based on phase-sensitive optical time domain reflectometry ( $\\phi$ -OTDR) technology for signal acquisition and pattern recognition strategies for threat identification. The proposal incorporates contextual information at the feature level in a Gaussian Mixture Model-Hidden Markov Model (GMM-HMM)-based pattern classification system and applies a system combination strategy for acoustic trace decision. System combination relies on majority voting of the decisions given by the individual contextual information sources and the number of states used for HMM modelling. The system runs in two different modes: (1) machine+activity identification, which recognizes the activity being carried out by a certain machine, and (2) threat detection, aimed to detect threats no matter what the real activity being conducted is. In comparison with the previous systems based on the same rigorous experimental setup, the results show that the system combination from the contextual feature information and the GMM-HMM approach improves the results for both machine+activity identification (7.6% of relative improvement with respect to the best published result in the literature on this task) and threat detection (26.6% of relative improvement in the false alarm rate with 2.1% relative reduction in the threat detection rate). Commission of the European Communities Joint Ministerio de Economía y Competitividad Comunidad de Madrid

Modelling traffic flows and estimating road travel times in transportation network under dynamic disturbances

Scipedia content — Tue, 16 Feb 2021 12:20:05 +0100

Traffic congestion is a common phenomenon in road transportation networks, especially during peak hours. More accurate prediction of dynamic traffic flows is very important for traffic control and management. However, disturbances caused by the time-varying origin-destination matrix, dynamic route choices, and disruptions make the modelling of traffic flows difficult. Therefore, this study focuses on modelling the dynamic evolution processes of traffic flows under disturbances and estimating dynamic travel times for arbitrary moment. A revised Lighthill–Whitham–Richards (RLWR) model with non-equilibrium states is presented to describe the dynamic traffic states on individual roads, and the ripple-spreading model (RSM) is integrated to investigate the interactions among several shockwaves from multiple roads. We propose a hybrid RLWR–RSM to model the congestion and congestion-recovery propagations in an entire transportation network. After predicting the dynamic traffic flows by the RLWR–RSM, the road travel times for arbitrary moment were estimated. Theoretical analyses indicated that (1) the RLWR–RSM inherits the advantages of macroscopic traffic flow models and integrates the characteristics of both low- and high-order continuum models, and (2) the RLWR–RSM considers multiple disturbances. From numerical experiments with various inputs, the variation in travel times under disturbances was investigated, and this further demonstrated that (1) the modelled dynamic traffic flows have four basic properties, and (2) the experimental results validate the theoretical analyses. In addition, the RLWR–RSM can explain several distinct traffic phenomena. Finally, the estimated travel times can provide decision supports for vehicle navigation. Keywords Traffic flow Disturbance Time-varying OD Route choice Network disruption Dynamic travel time

A methodological framework to evaluate the impact of disruptions on airport turnaround operations: A case study

Scipedia content — Tue, 16 Feb 2021 12:17:47 +0100

The efficiency and quality of airport airside operations are frequently compromised by various, unexpected disruptive events such as bad weather conditions, lack of handling staff and/or resources, strikes, aircraft diversions or technical failures, which may reduce airport airside operating capacity and affect the punctuality and regularity of the operations. In particular, disruptive events could lead to a substantial deviation of aircraft operations from the schedule, by causing the reduction of the system capacity and, thus, increasing congestion and flight delays, which worsen the overall performance of the air transport system. In this paper, the effects of unexpected events, particularly magnitude and duration, affecting airport airside operations are estimated within a general framework based on an element-by-element approach, adopted for the detailed representation and simulation of aircraft airside operations. The impacts generated by airport airside unexpected disruptions are modelled by using a discrete-event simulation model, dealing with both aircraft landing-and-takeoff (LTO) cycles and turnaround operations, developed and applied to the test case of a large regional airport.

Determinants of take-over time from automated driving: A meta-analysis of 129 studies

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

n important question in automated driving research is how quickly drivers take over control of the vehicle in response to a critical event or a take-over request. Although a large number of studies have been performed, results vary strongly. In this study, we investigated mean take-over times from 129 studies with SAE level 2 automation or higher. We used three complementary approaches: (1) a within-study analysis, in which differences in mean take-over time were assessed for pairs of experimental conditions, (2) a between-study analysis, in which correlations between experimental conditions and mean take-over times were assessed, and (3) a linear mixed-effects model combining between-study and within-study effects. The three methods showed that a shorter mean take-over time is associated with a higher urgency of the situation, not using a handheld device, not performing a visual non-driving task, having experienced another take-over scenario before in the experiment, and receiving an auditory or vibrotactile take-over request as compared to a visual-only or no take-over request. A consistent effect of age was not observed. We also found the mean and standard deviation of the take-over time were highly correlated, indicating that the mean is predictive of variability. Our findings point to directions for new research, in particular concerning the distinction between drivers’ ability and motivation to take over, and the roles of urgency and prior experience. © 2019 Elsevier Ltd

Power from above? Assessing actor-related barriers to the implementation of trolley truck technology in Germany

Scipedia content — Tue, 16 Feb 2021 12:16:00 +0100

In this paper, we present a new method to operationalize social barriers for innovative technologies. Technical feasibility and economic viability are no guarantee for the development and take-off of an innovation. We combine insights from multi-level perspective (MLP) and technological innovation systems (TIS) theory to develop a framework for the identification and evaluation of actor-centred barriers. We illustrate the method through an application to catenary hybrid truck (CHT) technology in Germany. Relevant stakeholders were identified via document research and subsequent network analysis, and then approached to fill out a survey. Additional data was gathered using semi-structured interviews with key actors, and content analysis. We show how the implementation of CHT may be hampered by resistance from the regime and by a lack of focused expectations and lobbying within the niche.

Estimating benefits of C-ITS deployment, when legacy roadside systems are present

Scipedia content — Tue, 16 Feb 2021 12:06:10 +0100

Cooperative systems which rely on vehicle-to-infrastructure communications are designed to tackle important road transport issues, such as safety, traffic efficiency and pollution. Since the associated monetary commitment to invest is substantial, a clear understanding of the likely costs, impacts and benefits is necessary before investment decisions can be made. A tool for estimating the costs and benefits, from both business and the societal point of view, was developed in the ANACONDA project, ‘assessment of user needs for adapting COBRA including online database’, to assist National Road Authorities (NRAs) during their decision processes. This study presents an approach for determining societal benefits by taking into account the presence of legacy roadside systems, which affect the size of the benefit reaped when cooperative intelligent transport systems (C-ITS) services are deployed. This study develops closed-form solutions for determining benefits to NRAs, taking into account the presence of legacy roadside systems. The COBRA + Tool incorporates these aspects, enabling NRAs to carry out ‘what-if’ scenarios for C-ITS deployment. The study provides examples of application of the Tool.

Hybrid simulated annealing and tabu search method for the electric travelling salesman problem with time windows and mixed charging rates

Scipedia content — Tue, 16 Feb 2021 12:04:38 +0100

The electric travelling salesman problem with time windows (ETSPTW) is an extension of the well-known travelling salesman problem with time windows (TSPTW). The ETSPTW additionally considers recharging operations of the electric vehicle at identical charging stations. However, different charging technologies used at public or private stations result in different charging times of the electric vehicles. Therefore, this study extends the ETSPTW by additionally considering charging operations at customer locations with different charging rates, called hereafter the electric travelling salesman problem with time windows and mixed charging rates (ETSPTW-MCR). To the best of our knowledge, this is the first study that considers both private and public charging stations for the ETSPTW. In addition to the extended version of the ETSPTW, this paper introduces a new and effective hybrid Simulated Annealing/Tabu Search (SA/TS) algorithm to solve the ETSPTW-MCR problem efficiently. Distinct from the existing hybridization of SA and TS, the proposed hybrid SA/TS algorithm employs efficient search procedures based on the TSPTW restrictions, a modified solution acceptance criterion, and an advanced tabu list structure. Moreover, an improved dynamic programming procedure is integrated to optimally find the charging station visits in shorter computational times. The proposed hybrid SA/TS is tested on several TSPTW and ETSPTW benchmark problems and compared with well-known solution approaches. Results of these experiments show that the proposed algorithm outperforms the other considered competitor algorithms both with regard to solution quality and computational time. Furthermore, 26 new best results are obtained for the ETSPTW instances. In addition, the hybrid algorithm is applied to a new problem set generated for the ETSPTW-MCR by extending the ETSPTW problems found in the literature. Comparisons with the ETSPTW results show that significant distance savings are found for most of the instances by charging the electric vehicle at customer locations. As a result of the computational studies, it should be concluded that the proposed algorithm is capable of finding efficient and more realistic route plans for the electric vehicles. ispartof: EXPERT SYSTEMS WITH APPLICATIONS vol:134 pages:279-303 status: Published online

Home charging and electric vehicle diffusion: Agent-based simulation using choice-based conjoint data

Scipedia content — Tue, 16 Feb 2021 12:03:57 +0100

Electric vehicles offer the potential of climate-friendly driving and have received more and more attention in diffusion research recently. However, the effect of the availability of home charging options on the market potential of electric vehicles has not been targeted in detail in the diffusion process so far, although it represents a beneficial differentiation to conventional vehicles. Therefore, we present an agent-based simulation to address the buying behavior of German consumers regarding electric and plug-in hybrid electric vehicles using empirical data primarily derived from a choice-based conjoint study. We explicitly consider individual possibilities of home charging in our model, which appears to have an important influence on the diffusion of both, electric and plug-in hybrid electric vehicles. However, its importance decreases with faster charging times at public charging stations. Furthermore, our findings reveal that in the longer term, technological progress in charging time, range, and charging station density of electric vehicles is presumably cannibalizing plug-in hybrid electric vehicles’ market shares more than that of conventional vehicles. However, with still lower technological capabilities of electric vehicles, a governmental subsidy can initially promote plug-in hybrid electric vehicles, but electric vehicles will benefit later from that promotional effect.

Hydrogen from renewables: Supply from North Africa to Central Europe as blend in existing pipelines – Potentials and costs

Scipedia content — Tue, 16 Feb 2021 12:03:30 +0100

© 2019 Elsevier Ltd Strong efforts are necessary to stem climate change. It requires to switch to renewable fuels. But as energy demand in Central Europe is high, renewable energy resources are of moderate quality, and available potentials are limited, energy imports from areas with beneficial renewable resources – such as North Africa – might be a promising option. Against this background this paper investigates the costs and potentials for hydrogen produced on the basis of electricity from wind and solar energy in North Africa and the subsequent transport as a blend with natural gas in existing pipelines. Linear optimization using hourly wind and solar data yields minimum hydrogen production cost. 2419 locations covering a 2° proximity of the existing natural gas pipeline infrastructure are considered in a lower and higher cost case for a near-term future (ca. 2020). Modell results provide lowest hydrogen production cost of 45 resp. 99 €/MWh. The production potential is in the range of PWh/a and therefore exceeds the hydrogen that can be transported in the existing infrastructure: Operating pipelines are potentially able to carry 10 vol% hydrogen in the natural gas feed with negligible adjustments to the infrastructure so that 9.5–23.2 TWh/a of hydrogen can be transported to Europe at minimum transport costs of 9 resp. 19 €/MWh. As these transport costs are low, supplying hydrogen leads to lower cost than transforming it to methane, Diesel or gasoline and is therefore the cheapest form of supplying a power based fuel. The hydrogen costs sum up to supply costs of 54 resp. 119 €/MWh free Central Europe.

Large-scale provision of frequency control via V2G: The Bornholm power system case

Scipedia content — Tue, 16 Feb 2021 11:57:41 +0100

This paper assesses the impact of electric vehicles (EVs) providing primary frequency regulation via vehicle-to-grid (V2G) technology. The aim of the work is to define a set of recommendations in order to guarantee a stable large-scale deployment of EV fleets as primary reserve providers. A realistic fleet model is proposed, which emulates the aggregated response of a number of EVs characterized by V2G hardware response times derived in laboratory tests. The effects of primary frequency control via EV fleets replacing conventional generating units are assessed with a sensitivity study in a single-bus power system with growing fleet sizes and response times. Two recommendations are derived to guarantee safe and stable operation: Recommendation 1 requires the share of EVs providing primary reserve to be smaller than the reserve from conventional units; Recommendation 2 requires response times below a given limit value, calculated as a function of the following power system parameters: the system inertia, the total primary reserve over the rotating generation capacity, and the employed droop gain. The full 60 kV power system of the Danish island of Bornholm is then employed to evaluate the validity of the proposed requirements on a real system with complex dynamics, non-linearities and voltage dependencies.

A review of revenue management : recent generalizations and advances in industry applications

Scipedia content — Tue, 16 Feb 2021 11:54:00 +0100

Originating from passenger air transport, revenue management has evolved into a general and indispensable methodological framework over the last decades, comprising techniques to manage demand actively and to further improve companies’ profits in many different industries. This article is the second and final part of a paper series surveying the scientific developments and achievements in revenue management over the past 15 years. The first part focused on the general methodological advances regarding choice-based theory and methods of availability control over time. In this second part, we discuss some of the most important generalizations of the standard revenue management setting: product innovations (opaque products and flexible products), upgrading, overbooking, personalization, and risk-aversion. Furthermore, to demonstrate the broad use of revenue management, we survey important industry applications beyond passenger air transportation that have received scientific attention over the years, covering air cargo, hotel, car rental, attended home delivery, and manufacturing. We work out the specific revenue management-related challenges of each industry and portray the key contributions from the literature. We conclude the paper with some directions for future research.\\ud \\ud

Assessing strategic flight schedules at an airport using machine learning-based flight delay and cancellation predictions

Scipedia content — Tue, 16 Feb 2021 11:44:54 +0100

To mitigate air traffic demand-capacity imbalances, large European airports implement strategic flight schedules, where flights are assigned arrival/departure slots several months prior to execution. We propose a generic assessment of such strategic schedules using predictions about arrival/departure flight delays and cancellations. We demonstrate our approach for strategic flight schedules in the period 2013–2018 at London Heathrow Airport. Together with the development of dedicated strategic flight schedule optimization models, our proposed approach supports an integrated strategic flight schedule assessment, where schedules are evaluated with respect to flight delays and cancellations.

A driving simulator experiment

Scipedia content — Tue, 16 Feb 2021 11:42:35 +0100

The involvement of cyclists in road crashes has not been decreasing with the same magnitude as the involvement of other road users. In particular, the interactions between cyclists and motorized traffic can lead to high-severity crashes. To improve the safety of these interactions, a thorough understanding of road user behaviour is first needed. In this study, we focused on drivers overtaking cyclists on rural roads. The two main objectives of this study were to develop models that predicted: (a) drivers’ decisions to perform either a flying or an accelerative overtaking manoeuvre in the presence of oncoming traffic, and (b) the lateral comfort distance that drivers maintain from cyclists during the overtaking. A driving simulator study was designed to assess driver decision-making during the overtaking. The 37 drivers who participated in the study each performed seven overtaking manoeuvres with oncoming traffic. Out of the 259 overtaking manoeuvres, 168 were flying and 91 were accelerative. Binary logistic-regression models with mixed effects predicted the type of overtaking strategy (flying or accelerative). Driving speeds were found to significantly affect the strategy. The overall performance of the models predicting the strategy was 85–90%. Models were also developed for predicting the lateral comfort distance. The results show that the lateral comfort distance is mostly affected by the longitudinal distance between the subject vehicle and the oncoming vehicle, the longitudinal distance between the subject vehicle and the cyclist, and the presence of an oncoming vehicle—as well as by the drivers’ characteristics (sensation seeking in flying overtaking manoeuvres and ordinary violations in accelerative manoeuvres). The root mean square error, which was used to assess the performance of the models, ranged from 0.56 to 0.62. In conclusion, the models predicting the overtaking strategy performed reasonably well, while the models predicting lateral distance did not provide accurate predictions. The models predicting overtaking strategy may support (1) the development and evaluation of active safety systems, (2) the design of automated driving, and (3) policy making.

The role of adoption norms and perceived product attributes in the adoption of Dutch electric vehicles and smart energy systems

Scipedia content — Tue, 16 Feb 2021 11:42:20 +0100

We studied to what extent perceived adoption norms affect the likelihood of adopting sustainable innovations, next to evaluations of the instrumental, environmental and symbolic attributes of these innovations. As hypothesised, results showed that people are more likely to adopt a sustainable innovation the more they evaluate the attributes of these sustainable innovations favourably and the more they think significant others would consider adoption (i.e., when adoption norms are strong). Moreover, we hypothesised and found that positive evaluations of the symbolic attributes are more likely to promote the adoption of sustainable innovations when people expect that few significant others would consider adoption. These findings suggest that weak adoption norms that are typical in the early adoption stage may both inhibit and promote adoption of sustainable innovations, via different routes.

Minimizing crane times in pre-marshalling problems

Scipedia content — Tue, 16 Feb 2021 11:40:50 +0100

The pre-marshalling problem has been extensively studied in recent years with the aim of minimizing the number of movements needed to rearrange a bay of containers. Time is a more realistic objective for measuring process efficiency, and we show that it does not correlate with the number of movements. As a result, we study the problem of minimizing crane times and develop two exact approaches to solve it: an integer linear model, and a branch and bound algorithm, with new upper and lower bounds, dominance criteria, and a heuristic procedure, to provide optimal solutions for problems of practical size.

An analysis of energy flow in a turbocharged diesel engine of a heavy truck and potentials of improving fuel economy and reducing exhaust emissions

Scipedia content — Tue, 16 Feb 2021 11:39:07 +0100

The impetus of the internal combustion engine developments is the reductions of the fuel consumptions and exhaust emissions. Thermal management is an efficient method to decrease the exhaust emissions and enhance fuel economy. In order to further optimize the thermal management of internal combustion engines, a detailed analysis of the energy flow in each component of internal combustion engines is indispensable. In this paper, the test bench of a heavy duty diesel engine was established to obtain the target parameters. The energy distributions in each component of the diesel engine, including compressor, intercooler, shaft power, turbine, coolant and exhaust, were calculated using tested parameters. The lubricating oil consumption was also taken into consideration. In addition, the potential influences of different turbochargers on the total thermal efficiency were analyzed. The results showed that the thermal efficiency of the diesel engine was more than 38% when the engine operated at 50%–100% engine load and 1000 rpm–1700 rpm conditions. The energy loss by coolant was more than 50% of the total fuel energy consumption in the low power output conditions. However, it was lower than 30% in high power output conditions, and the thermal loss was more than 150 kW around rated power conditions. The maximum proportion of the energy being consumed by turbine was ∼10% of the fuel energy; additionally, the exhaust energy distributions changed significantly after the turbine expansion. 1%–3% of the fuel energy was recycled by the turbocharger, then, flowed into the cylinders. The energy loss through the intercooler accounted for ∼6% of the fuel energy. Significant reductions of exhaust emissions and fuel consumptions can be achieved by optimizing the coolant and lubricating oil thermal conditions. Turbochargers presented a huge effect on exhaust temperature distributions at high power output conditions, and the total thermal efficiency changed significantly if all kinds of energy recovery approaches were applied.

Smart cycling futures: Charting a new terrain and moving towards a research agenda

Scipedia content — Tue, 16 Feb 2021 11:37:19 +0100

The future of cycling is about to change. At least, this is apparent if we are to believe the multitude of innovators, start-ups, incumbent industries, policy actors and consultants proposing to harness the power of digital techniques to improve and transform cycling experiences, infrastructures, and gadgets. This ‘smartification of cycling’ is a phenomenon that is increasingly attracting attention and a variety of interests, fuelled both by the processes of transitioning to smart mobility and a boom of attention to cycling in cities worldwide. However, proposed cycling futures, both implicit and explicit, receive little critical scrutiny. Here, we fill this gap by mapping smart cycling innovations and their key features. We examine how innovations are believed to change the way cycling is practiced, made sense of and governed. Using a constructivist grounded theory approach, we analyse 86 website texts of smart cycling innovations and systematically outline changes envisioned by innovators. Having identified tensions between and within a range of promised futures, we conclude that smart cycling futures are multiple and contested, just as cycling presents are. Therefore, we propose a number of questions for further research to advance a more nuanced understanding of the range of futures of smart cycling in academic thinking and potentially to support decision-making at different levels of governance. Understanding diverse, contested, embodied and embedded cycling presents is part and parcel of imagining and co-creating (smart) cycling futures.

Platoon of SAE Level-2 Automated Vehicles on Public Roads: Setup, Traffic Interactions, and Stability

Scipedia content — Tue, 16 Feb 2021 11:27:55 +0100

n increasing amount of vehicles are equipped with driver assistance systems; many of the vehicles currently on the market can be optionally equipped with adaptive cruise control and lane centering systems. Using both systems at the same time brings the vehicle to SAE level-2 automation. This means a driver does not need to perform longitudinal and lateral operational driving, although the driver should be ready to intervene at any time. While this can provide comfort, the interaction between vehicles operated by these systems might cause some undesired effects. This becomes particularly relevant with increasing market penetration rates. This paper describes an experiment with seven SAE level-2 vehicles driven as a platoon on public roads for a trip of almost 500 km. The paper discusses how the experiment was organized and the equipment of the vehicles. It also discusses the interaction of the platoon in traffic, as well as, in basic terms, the interaction between the automated vehicles. The experiences can be useful for other studies setting up field tests. The conclusion from this platoon test is: intentionally creating platoons on public roads is difficult in busy traffic conditions. Moreover, interactions between the vehicles in the platoon show that the current SAE level-2 systems are not suitable for driving as platoons of more than typically three to four vehicles, because of instabilities in the car-following behavior. © National Academy of Sciences: Transportation Research Board 2019.

A risk assessment method for "Eurobalise" fastening system: managing the sensor/sleeper interaction in the high-speed railway infrastructure

Scipedia content — Tue, 16 Feb 2021 11:22:36 +0100

The aim of this research is to define a breakage limit for the fastening system of the "Eurobalise" device of the ERTMS/ETCS rail signalling system on the European railways. The widespread presence of the system along the European railway line and the increasing of high-speed lines have led the research to find design solutions able to increase the attack system strength, avoiding its detachment from the sleepers. Mechanical tests on tensile, shear and bending configurations have been carried out to evaluate the jointing systems between Eurobalise and sleepers. Additional full-scale tests allowed the definition of the load actions and of the breaking points. The connection between balise and sleepers is able to react to the train’s aerodynamic actions, confirming the system reliability even for the passage of high-speed trains. Through the experimental approach were defined standard test procedures useful to improve the sheet data of this kind of fastening system.

Bike-sharing or taxi? Modeling the choices of travel mode in Chicago using machine learning

Scipedia content — Tue, 16 Feb 2021 11:21:44 +0100

In many big cities, the bike-sharing system (BSS) and taxi play critical roles in transportation services. They both offer on-demand transportation options and allow flexible riding scheduling and routing. Previous literature has compared BSS and taxi to other transport modes, such as public transit and private automobile, but little is known about the spatiotemporal factors that influence travel choices between these two alternatives. Understanding travel patterns of BSS and taxi is critical in traffic demand analysis and sustainable transportation planning. Also, an in-depth examination of the patterns of travel behaviors, especially when one would choose BSS over a taxi, will provide valuable insights on human mobility and active living research. In this study, we investigated the spatiotemporal patterns of BSS and taxi trips in Chicago from 2014 to 2016. To model travel choices between BSS and taxi, we applied machine learning techniques to simulate the means of transport based on environmental and temporal factors. Results show seasonal trip variations of the BSS and a declining trend of taxi trips. BSS speed is relatively stable while taxi speed varies primarily because of time and locations. Based on the random forest model, which has demonstrated the best fit with high processing speed, travel distance and the number of parks and recreational facilities seem to be critical spatial predicting factors of the travel choice. Given any time and location, the model can recommend the travel choices between BSS and taxis for users. This study shows the significance of machine learning techniques in urban mobility research. Results of the study may potentially support people's transportation decision-making and facilitate sustainable transportation planning.

Unanticipated implications for society and governance

Scipedia content — Tue, 16 Feb 2021 11:17:48 +0100

In this paper we focus on the development of a new service model for accessing transport, namely Mobility as a Service (MaaS) and present one of the first critical analyses of the rhetoric surrounding the concept. One central assumption of one prevalent MaaS conceptualization is that transport services are bundled into service packages for monthly payment, as in the telecommunication or media service sectors. Various other forms of MaaS are being developed but all tend to offer door-to-door multi-modal mobility services, brokered via digital platforms connecting users and service operators. By drawing on literature concerned with socio-technical transitions, we address two multi-layered questions. First, to what extent can the MaaS promises (to citizens and cities) be delivered, and what are the unanticipated societal implications that could arise from a wholesale adoption of MaaS in relation to key issues such as wellbeing, emissions and social inclusion? Second, what are de facto challenges for urban governance if the packaged services model of MaaS is widely adopted, and what are the recommended responses? To address these questions, we begin by considering the evolution of intelligent transport systems that underpin the current vision of MaaS and highlight how the new business model could provide a mechanism to make MaaS truly disruptive. We then identify a set of plausible unanticipated societal effects that have implications for urban planning and transport governance. This is followed by a critical assessment of the persuasive rhetoric around MaaS that makes grand promises about efficiency, choice and freedom. Our conclusion is that the range of possible unanticipated consequences carries risks that require public intervention (i.e. steering) for reasons of both efficiency and equity. Peer reviewed

Pedestrian road-crossing willingness as a function of vehicle automation, external appearance, and driving behaviour

Scipedia content — Tue, 16 Feb 2021 11:17:16 +0100

This paper discusses whether the knowledge of the driving mode of an approaching vehicle (manual vs. automated) influences pedestrians’ decisions while crossing a street. Additionally, the paper explores how different appearances and driving behaviours of vehicles interact with driving mode in affecting pedestrians’ road-crossing behaviours. In a video-based experiment with sixty participants, two vehicles with different appearances (a BMW 3 and a Renault Twizy) were presented as either manually-driven or automated vehicles. Both vehicles displayed either yielding or non-yielding behaviour on a straight road devoid of other traffic. Participants were asked to indicate whether they would cross the street in front of the approaching vehicle, at different distances ranging from 45 m to 1.5 m. The results showed that there was no significant influence of the knowledge of the driving mode (manually-driven vs automated) on pedestrians’ willingness to cross the street at any distance. The vehicle’s behaviour (whether it is maintaining speed or yielding) played a dominant role in pedestrians’ decision to cross a road, and this was similar for both modes and both vehicles, at all distances. However, results suggested that in situations and at distances when the intent of the vehicle was not fully clear by the behaviour of the car alone, there were differences between the two vehicles at certain distances, which could be attributed to the differences in their appearance such as size, aggressiveness and novelty. A futuristic-looking vehicle inspired less confidence in road-crossing situations compared to an ordinary-looking vehicle. Additionally, a novel and futuristic-looking vehicle appeared to make it easier for people to believe that it is an automated vehicle. We conclude by discussing design implications for the development of external HMIs automated vehicles.

SAPIENT: Enabling Real-Time Monitoring and Control in the Future Communication Infrastructure of Air Traffic Management

Scipedia content — Tue, 16 Feb 2021 11:14:27 +0100

This paper describes the SAPIENT system, a real-time monitoring and control infrastructure for Air Traffic Management. Within the latter, aircrafts constantly measure the state and quality of their datalinks, and report these measurements to a ground entity, tagging them with a time/space reference. The ground entity, then, builds a map of the monitored portion of the sky, and can feed back information to the aircrafts themselves regarding conditions that they would not be able to measure otherwise. This allows optimal vertical handover decisions to be made, increasing service continuity and improving communication performance. We show that the SAPIENT system can be implemented using existing technologies, without the need for expensive hardware. Moreover, we show via simulation that a small, negligible increase in the communication overhead due to SAPIENT reporting brings about considerable benefits.

Tensile strength of the unbonded flexible pipes

Scipedia content — Tue, 16 Feb 2021 11:10:04 +0100

Flexible pipelines must be designed considering the extreme situation for which additional components are needed against severe loading and environmental conditions. Tensile armor is employed in case of high tensile forces, which increase with water depth; and massive components used against high internal and external pressures. In this paper, the mechanical behavior of the pipe under pure tension is investigated by both theoretical and numerical analysis, then the contribution of the external pressure to the axial problem is examined using an analytical analysis. As the deformations along the longitudinal direction of the studied pipe highly depend on the radial stiffness of the cross section, the influence of the pressure armor is carefully evaluated in the inception phase, and its radial stiffness is verified by its own numerical results. The plastic behavior for both steel and polymer layers is taken into account by using the secant modulus method. Moreover, this work answers a question raised by producers that need to know when tensile armor is required to reinforce Metallic Strip Flexible Pipes (MSFP). The theoretical model is employed to carry out the comparison between pipes with different configurations, in order to investigate the influencing parameters of the tensile stiffness. The results obtained from the theoretical and the numerical simulations lead to a remarkable confidence in the analytical solution thanks to a relatively small difference between the outcomes.

Gaze behaviour and electrodermal activity: Objective measures of drivers’ trust in automated vehicles

Scipedia content — Tue, 16 Feb 2021 10:59:19 +0100

Studies show that drivers’ intention to use automated vehicles is strongly modulated by trust. It follows that their benefits are unlikely to be achieved if users do not trust them. To date, most studies of trust in automated vehicles have relied on self-reports. However, questionnaires cannot capture real-time changes in drivers’ trust, and are hard to use in applied settings. In previous work, we found evidence that gaze behaviour could provide an effective measure of trust. In this study we tested whether combining gaze behaviour with Electrodermal Activity could provide a stronger metric. The results indicated a strong relationship between self-reported trust, monitoring behaviour and Electrodermal Activity: The higher participants’ self-reported trust, the less they monitored the road, the more attention they paid to a non-driving related secondary task, and the lower their Electrodermal Activity. We also found evidence that combined measures of gaze behaviour and Electrodermal Activity predict self-reported trust better than either of these measures on its own. These findings suggest that such combined measures have the potential to provide a reliable and objective real-time indicator of driver trust. © 2019 Elsevier Ltd

An exploration of factors affecting mode combination choice of travelers in England

Scipedia content — Tue, 16 Feb 2021 10:53:40 +0100

tremendous growth has been observed in the use of personal vehicles. Increase in private vehicle use has created many environmental, social and economic problems. A multi-stage trip can help to elevate the problems of delays, environmental degradation, and congestion. Multi-stage trips provide the benefits of smarter, cleaner and sustainable transport. This paper focuses on the organization of different multi-stage trips with respect to first mile, main stage, and last mile and factors that influence the choice of these mode combinations. A multinomial logistic regression (MNL) model is used to evaluate the factors that affect the choice of different mode combinations in a multi-stage trip. For most of the combinations, the trip purpose is significantly associated with mode choice for these combinations. In most cases, availability of the car results in a decline of probability for choosing a combination involving walk. The families with children prefer to take a combination involving a car or public transport at the first or last mile. This study only focuses on the mode combination of 3-stage trips so, an analysis can also be made for multi-stage trips having more than 3 stages.

Modeling Deformation of Corroded Buried Steel Pipes and Design of Protective Measure

Scipedia content — Tue, 16 Feb 2021 10:50:26 +0100

"jats:p"Corrosion damage is reported to be one of the leading causes of steel pipeline failure causing significant financial losses to operators and damage to the surrounding environment. As part of a rising confrontation to pipeline integrity management, researchers are continuously seeking better ways to assist on how to identify, assess, and prevent such incidents. Thus, there is a crucial need to establish a connection between assessment of pipeline condition and its structural stability. To achieve this, a three-dimensional finite element (FE) model is developed. The effects of geometry parameters such as defect thickness and spread angle are considered. Results show that thicker pipelines with corrosion groove perform better structurally than slender equivalents. The impact of corrosion damage is assessed to be significant on pipe stability with pipelines experiencing higher displacement and wall stresses with increasing defect depth and spread angle. A protective measure has been proposed using the buried pipes bedding system. The most critical spread angle is at 60 deg for unprotected pipe sections and 90 deg for bedded protected sections.

Transitions to manual control from highly automated driving in non-critical truck platooning scenarios

Scipedia content — Tue, 16 Feb 2021 10:48:52 +0100

utomated truck platooning is getting an increasing interest for its potentially beneficial effects on fuel consumption, driver workload, traffic flow efficiency, and safety. Nevertheless, one major challenge lies in the safe and comfortable transitions of control from the automated system back to the human drivers, especially when they have been inattentive during highly automated driving. In this study, we investigated truck drivers’ take-over response times after a system initiated request to take back control in non-critical truck platooning scenarios. 22 professional truck drivers participated in the truck driving simulator experiment and everyone was instructed to drive under three task conditions during highly automated driving: Driver monitoring condition (drivers were instructed to monitor the surroundings), Driver not-monitoring condition (drivers were provided with a hand-held tablet and were asked to use this), and Eyes-closed condition (drivers were not allowed to open their eyes). The total take-over response time was divided into the perception response time and the movement response time by manual video annotation. Results showed significantly longer total take-over times with high variability in both Driver not-monitoring and Eyes-closed conditions compared to the Driver monitoring condition. Hand movement response time was found to be the dominant component of the total take-over time, being influenced by the motoric manoeuvres to resume physical readiness before taking over control (e.g., putting away the hand-held tablet, or adjusting seating position). These results suggest the importance of a personalized driver readiness predictor as an input parameter for a safe and comfortable transition of control. © 2019 Elsevier Ltd

Public responses to an environmental transport policy in Sweden: Differentiating between acceptance and support for conventional and alternative fuel vehicles

Scipedia content — Tue, 16 Feb 2021 10:40:50 +0100

Understanding public responses to environmental policies can"br/"help in achieving a move towards more renewable energy. Focusing on two"br/"types of public responses to a policy, namely public acceptance and"br/"public support, this study utilizes a survey of car owners (N=1,422) to"br/"explore public responses to an environmental transport policy in Sweden."br/"The results demonstrate higher levels of public acceptance than support"br/"for the policy and that adopters of Alternative Fuel Vehicles (AFVs) are"br/"more prone to accept and support the policy by expressing higher"br/"intentions for continuous AFV adoption. Results of regression analyses"br/"show that policy acceptance can be explained by environmental beliefs and"br/"previous experience with AFVs. In addition, public support is also"br/"explained by public acceptance, even when controlling for other factors,"br/"which lends support to the deduction that policy acceptance can be"br/"theorized as antecedent to policy support. This study emphasizes the"br/"importance of understanding different types of public responses to an"br/"energy policy in order to recognize drivers for, and barriers against,"br/"successfully implementing a policy and communicating it with the public.

Public transport provision under agglomeration economies

Scipedia content — Tue, 16 Feb 2021 10:32:26 +0100

The purpose of this paper is to investigate, using both theoretical and numerical analysis, the impact of agglomeration externalities on short-run policy decisions in public transport, i.e. socially optimal pricing, frequency setting, and subsidisation. We develop a simple two-mode model in which commuters can opt for car or public transport use; car use leads to congestion, and public transport is subject to crowding. Allowing for agglomeration externalities, we show the following results. First, if car use is correctly priced for congestion, agglomeration benefits imply substantially lower public transport fares and higher frequencies. They neutralise to some extent the pressure to increase fares to correct the crowding externality. Second, as a consequence, agglomeration benefits justify low cost recovery ratios in public transport. Assuming an agglomeration elasticity of 1.04, a value well within the range of reported elasticities, numerical implementation of the model finds that cost-recovery ratios are 35.8% lower than in the absence of the productivity externality. Third, interestingly, the effect of agglomeration benefits on fares and frequency is much smaller if road use is exogenously under-priced. In this case, any modal shift induced by lower public transport fares has opposing agglomeration effects on the two modes, since agglomeration benefits are not mode-specific.

A quasi-3D approach for the assessment of induced AC interference on buried metallic pipelines

Scipedia content — Tue, 16 Feb 2021 10:30:52 +0100

In this paper, a novel quasi-three dimensional technique for the study of electromagnetic interferences induced by overhead power lines on buried metallic pipelines located in the same corridor is proposed. The aim of the method is to provide an inherently three dimensional solution to the problem, by using a two dimensional finite element approach. According to the proposed methodology, a bidimensional quasi-magnetostatic analysis is performed on a section of the considered corridor. The three dimensional extension is obtained by using a circuital approach to consistently couple the analysed section with the rest of the system. The analysis of the obtained equivalent circuit finally provides the actual values of the longitudinal electric fields acting on the studied section, and thus allows the solution of the problem. The results obtained from the described procedure have been compared for a few simple interference cases with those obtained using Carson’s analytical formulas for the calculation of mutual impedances. Finally, a study on the effects of a non-homogeneous soil structure has been carried out.

Governing urban diversity: Multi-scalar representations, local contexts, dissonant narratives

Scipedia content — Tue, 16 Feb 2021 10:29:51 +0100

In recent academic and urban policy writings the term urban diversity is usually understood, or discussed within the context of, increasing ‘socio-cultural’ diversity in cities or is explicitly connected to debates over immigration and demographic change. Although policy agendas follow certain common trends ‘to deal with’ the consequences of diversity, there is a lack of evidence-based research on how representations of diversity are mobilised and implemented by institutions of governance operating at multiple scales and how these narratives relate to each other. Policy-makers are faced with new dilemmas over how to govern and manage cities that are becoming increasingly diverse, on the one hand, and increasingly ‘sensitive’ to certain channels of flows of people (such as refugees), on the other. In some cases, city authorities promote the idea of inclusive diversity as a mark of modernisation and tolerance. In others, its recognition may be seen as a threat to an imagined social order and is perceived to be fuelling neo-assimilationist policies in many European Union cities. This special issue aims to fill this gap by providing evidence-based research outcomes that tackle different dimensions of the governance of diversity in cities. The principal aim of the research project, named DIVERCITIES, that underpins this collection was to critically assess evidence concerning the range of socio-economic outcomes that may emerge from the presence of greater urban diversity. DIVERCITIES has shown that city policy agendas across Europe are often more ‘positive’ towards diversity than national policies and media reports. Moreover, local policy initiatives, mostly formed at the bottom-up scale, sometimes as a cooperation between state and civic actors and sometimes as purely private or even individual arrangements, address the actual needs of certain population groups by acting as bridge-builders between public authorities and target groups. This collection aims to provide a clear understanding of how diversity is understood, operationalised and dealt with at different scales of policy-making. In focusing on European examples, it provides an important addition to a literature that has become Anglo-American focused, both in terms of the concepts and policy interventions.

Collaborative urban transportation: Recent advances in theory and practice

Scipedia content — Tue, 16 Feb 2021 10:28:51 +0100

Increasing urbanization has turned transporting freight from, to, and within urban areas into a major challenge. Freight transportation represents a lifeline for urban retail and industry, but causes significant negative impacts on the quality of living in urban areas in terms of congestion, emissions and space consumption. City logistics initiatives have long suggested the need for collaborative and environmentally friendly urban transportation that could alleviate the negative impacts of urban transportation, but these face organizational and technological challenges of collaboration. Given technological advancements and innovative business models, concepts of collaborative urban transportation could contribute to a future paradigm of more sustainable and customer-friendly urban transportation. In this work, we collect and discuss contributions to collaborative freight transportation in urban areas with focus on recent publications (i.e. those published over the past ten years). We particularly analyze vertical and horizontal approaches of collaboration from an operations research perspective and point out strategic, tactical, and operational planning problems and solution approaches. To highlight research gaps and future research opportunities, we present innovative examples of collaborative urban transportation and analyze factors of failure and success. Collecting recent advances in theory and practice of collaborative urban transportation allows us to distill alternative visions of future collaborative freight transportation in urban areas. (C) 2018 Elsevier B.V. All rights reserved.

A numerical model for the calculation of electromagnetic interference from power lines on nonparallel underground pipelines

Scipedia content — Tue, 16 Feb 2021 10:26:14 +0100

This work proposes a numerical methodology for the calculation of currents and voltages induced on underground pipelines by nearby overhead power lines. A previously developed quasi-3D methodology is extended, allowing the investigation of nonparallel routings of the pipelines with respect to the power lines. The proposed technique is based on a discretization of the pipeline path into several segments parallel to the power line. The section of the corridor corresponding to each pipeline segment is regarded as an electrical multi-port component, whose electrical parameters are extracted via finite element 2D analysis. Then, the obtained components are integrated into a network embodying the physical characteristics of the whole corridor. In this way, the circuital analysis is used to extend the capabilities of a standard two-dimensional field analysis. The proposed methodology is employed to simulate a pipeline running parallel to a power line for a distance of 12km. Afterwards, several nonparallel configurations – consisting of crossings between a pipeline and a power line – are assessed. The physical consequences of the crossing are discussed and a convergence study is performed to investigate the optimal pipeline subdivision procedure to be adopted for a set of different crossing angles.

Developing adaptive traffic signal control by actor-critic and direct exploration methods

Scipedia content — Tue, 16 Feb 2021 10:25:42 +0100

Designing efficient traffic signal controllers has always been an important concern in traffic engineering. This is owing to the complex and uncertain nature of traffic environments. Within such a context, reinforcement learning has been one of the most successful methods owing to its adaptability and its online learning ability. Reinforcement learning provides traffic signals with the ability automatically to determine the ideal behaviour for achieving their objective (alleviating traffic congestion). In fact, traffic signals based on reinforcement learning are able to learn and react flexibly to different traffic situations without the need of a predefined model of the environment. In this research, the actor-critic method is used for adaptive traffic signal control (ATSC-AC). Actor-critic has the advantages of both actor-only and critic-only methods. One of the most important issues in reinforcement learning is the trade-off between exploration of the traffic environment and exploitation of the knowledge already obtained. In order to tackle this challenge, two direct exploration methods are adapted to traffic signal control and compared with two indirect exploration methods. The results reveal that ATSC-ACs based on direct exploration methods have the best performance and they consistently outperform a fixed-time controller, reducing average travel time by 21%.

Visual Analysis of Place Connectedness by Public Transport

Scipedia content — Tue, 16 Feb 2021 10:23:42 +0100

The concept of place connectedness (traditionally termed ‘accessibility’) refers to the ability of people to reach various services and to participate in activities. Connectedness by public transport is especially important for underprivileged and elderly people while the active use of public transport by the general population contributes in reducing traffic congestions and air pollution in cities. Place connectedness analyses are performed for a variety of purposes. In communication with transportation experts, we performed the conceptual modeling of the domain of problems related to place connectedness, defined the system of analysis tasks, and matched the tasks to visual analytics techniques that are capable to support them. In this paper, we introduce the task typology and present the visual analytics techniques using several example scenarios of place connectedness analyses.

Identifying transient and variable sources in radio images

Scipedia content — Tue, 16 Feb 2021 10:18:22 +0100

With the arrival of a number of wide-field snapshot image-plane radio transient surveys, there will be a huge influx of images in the coming years making it impossible to manually analyse the datasets. Automated pipelines to process the information stored in the images are being developed, such as the LOFAR Transients Pipeline, outputting light curves and various transient parameters. These pipelines have a number of tuneable parameters that require training to meet the survey requirements. This paper utilises both observed and simulated datasets to demonstrate different machine learning strategies that can be used to train these parameters. The datasets used are from LOFAR observations and we process the data using the LOFAR Transients Pipeline; however the strategies developed are applicable to any light curve datasets at different frequencies and can be adapted to different automated pipelines. These machine learning strategies are publicly available as Python tools that can be downloaded and adapted to different datasets (https://github.com/AntoniaR/TraP_ML_tools).

Comment: Astronomy & Computing Accepted, 25 pages, 20 figure

Pathways for a sustainable future inland water transport: A case study for the European inland navigation sector

Scipedia content — Tue, 16 Feb 2021 10:09:33 +0100

Sustainable transport is an important way of mitigating climate change. Inland navigation still is a sustainable mode of transport which is of great importance for the whole European transport market. However, due to its market structure, it risks losing the battle for volume and market share with the other transportation modes. Opting for inductive research approach, this paper first of all collects data. Next, the paper observes the market of the European inland navigation sector and looks for patterns in order to develop a set of structural pathways. From the data collection, it turns out that the sector is facing challenges, mainly due to overcapacity, uncontrolled costs and volatile freight prices. The classical reaction pattern to overcome these shortcomings (capacity control, cost control, playing with ‘time’ and ‘reliability’ factors) does no longer suffice. By analyzing the patterns, the researchers were able to formulate five pathways: A first path is that of technological/operational innovation or retrofitting for ecological and social sustainability. A second path is that of industrial economics: inland navigation is marked by a lot of fragmentation. A solution might be pooling up, whereby the risk of anti-competitive impacts seems very low. A third path is that of financing: the classical financing through banks clearly provides no incentive for reducing overcapacity, even not through bankruptcies. Actual lay-up of vessels seems a must. For longer-run financing, bonds, credit unions or even crowd-funding can be solutions. A fourth path builds on the second one, with more co-operation needed within the wider sector, also with vertically-related partners: charterers, terminal operators, etc. Fifth and finally, a dynamic regulation is needed, following modern rules, with an eye on the longer-term viability of the sector.

Data on the interference induced on a buried pipeline by an overhead power line

Scipedia content — Tue, 16 Feb 2021 10:09:20 +0100

The data presented in this article relate to the research article "A quasi-3D approach for the assessment of induced AC interference on buried metallic pipelines" (Popoli et al., 2018) [1]. The current induced on a pipeline versus the distance between the overhead power line and the pipeline is presented. Various configurations of the overhead power line are considered. The calculations are based on method that combines 2D FEM simulations with circuital analysis. (C) 2019 Published by Elsevier Inc.

The Dutch smart mobility policy as an example of a transformative STI policy

Scipedia content — Tue, 16 Feb 2021 10:04:54 +0100

"jats:p"The recent orientation toward societal challenges in Science, Technology, and Innovation (STI) policies has exposed the limitations of contemporary governance to deal with these endeavors. For this reason, it has been urged a shift toward the so-called ‘transformative change’ approach, drawn from socio-technical transitions literature. This research suggests that this approach can be considered an emerging policy paradigm, and studies the implications of its adoption in STI policy. For doing so, we developed a conceptual framework based on policy sciences and STI policy literature, and used to study a policy resembling this societal challenge orientation: the Dutch smart mobility policy. Our case study suggests that the transformative change approach can be considered a new paradigm in STI policy, as novel theories, approaches, and mechanisms are being used to govern this policy. This research contributes to a better understanding of transformative approaches, by empirically looking the changing role of governance in societal challenge-led STI policies.

Recovering the “new twin”: Analysis of secondary neodymium sources and recycling potentials in Europe

Scipedia content — Tue, 16 Feb 2021 09:57:38 +0100

Sustainable management strategies for securing long–term supply of rare earth elements is priority for Europe due to a complex and interlinked production chain and its dependence on Chinese export. Among rare earth elements, neodymium captured most attention due to its essential role in a wide spectrum of applications including green–energy technologies such as wind turbines and electric vehicles. Being complementary to primary production, end–of–life recycling would diversify neodymium supply, relieve the Chinese dominance on primary production and contrast the balance problem. However, neodymium recycling at end–of–life is not yet in place. In this work, we developed a dynamic material flow model to investigate neodymium stocks and flows in the EU–28 to 2016. The analysis enabled a detailed investigation of secondary sources of neodymium, which set essential boundary conditions for material recovery and recycling. We found that roughly up to 50% of the annual neodymium demand in the EU–28 could be met by domestic secondary supply, if latent recycling potentials were turned into actual capacity. Significant energy savings and GHG emissions cut could be also attained. However, product design, end–of–life collection, and scrap price issues are primary obstacles to neodymium recovery. Thus, unless going beyong those limits, establishing and maintaining a sustainable recycling chain for neodymium in the EU–28 will remain problematic.

Learning-Based Quality Control for Cardiac MR Images

Scipedia content — Mon, 15 Feb 2021 12:33:59 +0100

The effectiveness of a cardiovascular magnetic resonance (CMR) scan depends on the ability of the operator to correctly tune the acquisition parameters to the subject being scanned and on the potential occurrence of imaging artefacts such as cardiac and respiratory motion. In the clinical practice, a quality control step is performed by visual assessment of the acquired images: however, this procedure is strongly operator-dependent, cumbersome and sometimes incompatible with the time constraints in clinical settings and large-scale studies. We propose a fast, fully-automated, learning-based quality control pipeline for CMR images, specifically for short-axis image stacks. Our pipeline performs three important quality checks: 1) heart coverage estimation, 2) inter-slice motion detection, 3) image contrast estimation in the cardiac region. The pipeline uses a hybrid decision forest method - integrating both regression and structured classification models - to extract landmarks as well as probabilistic segmentation maps from both long- and short-axis images as a basis to perform the quality checks. The technique was tested on up to 3000 cases from the UK Biobank as well as on 100 cases from the UK Digital Heart Project, and validated against manual annotations and visual inspections performed by expert interpreters. The results show the capability of the proposed pipeline to correctly detect incomplete or corrupted scans (e.g. on UK Biobank, sensitivity and specificity respectively 88% and 99% for heart coverage estimation, 85% and 95% for motion detection), allowing their exclusion from the analysed dataset or the triggering of a new acquisition.

Document type: Article

Converting a Conventional Vehicle into an Electric Vehicle (EV)

Scipedia content — Mon, 15 Feb 2021 12:33:39 +0100

The electric vehicle (EV) is not a recent invention. Between the end of the XIX century and the beginning of the XX century, most motor vehicles were electric, due to their superior reliability and cleanliness, compared to that of vehicles driven by internal combustion engines (ICE). However, with the development of ICEs and the reduction of their price, electric cars were forgotten. Only almost a century later, they returned in the market due to a significant increase in fossil fuels prices, as well as to a growing environmental concern. EVs present a number of advantages over ICE vehicles: they are simpler and require less use and replacement of parts, resulting in lower maintenance costs; moreover, they do not release pollutants into the environment. However, their production cost is still much higher than that of ICE vehicles. In order to verify the possibility of converting a conventional vehicle into an electric one at a reasonable cost, achieving a good performance and a good kWh/km ratio, an ICE-powered Mercedes-Benz Class A 190 was converted into an EV. The results of several tests indicate that the conversion is feasible, as the car reached an average travelling cost of 0.16 R$/km, assuming a price for the energy of 0.63 R$/kWh. Moreover, this cost could be as low as zero if solar radiation is utilized to generate electricity through photovoltaic panels, which is an even more environmentally sustainable solution..

Document type: Article

A Modified Inverse Distance Weighting Method for Interpolation in Open Public Places Based on Wi-Fi Probe Data

Scipedia content — Mon, 15 Feb 2021 12:31:38 +0100

Urban open places with a public service function (e.g., urban parks) are likely to be populated in peak hours and during public events. To mitigate the risk of overcrowding and even events of stampedes, it is of considerable significance to realize a real-time full coverage estimate of the population density. The main challenge has been the limited deployment of crowd surveillance detectors in open public spaces, leading to incomplete data coverage and thus impacting the quality and reliability of the density estimation. To remedy this issue, this paper proposes a modified inverse distance weighting (IDW) method, named the inverse distance weighting based on path selection behavior (IDWPSB) method. The proposed IDWPSB method adjusts the distance decay effect according to visitors’ path selection behavior, which better characterizes the human dynamics in open spaces. By implementing the model in a real-world road network in the Shichahai scenic area in Beijing, China, the study shows a decrease in the absolute deviation by 17.62% comparing the results between the new method and the traditional IDW method, justifying the effectiveness of the new method for spatial interpolation in open public places. By considering the behavioral factor, the proposed IDWPSB method can provide insights into public safety management with the increasing availability of data derived from location-based services.

Document type: Article

Benchmarking of 4C-seq pipelines based on real and simulated data

Scipedia content — Mon, 15 Feb 2021 12:27:33 +0100

"jats:sec" "jats:title"Motivation"/jats:title" "jats:p"With its capacity for high-resolution data output in one region of interest, chromosome conformation capture combined with high-throughput sequencing (4C-seq) is a state-of-the-art next-generation sequencing technique that provides epigenetic insights, and regularly advances current medical research. However, 4C-seq data are complex and prone to biases, and while specialized programs exist, an unbiased, extensive benchmarking is still lacking. Furthermore, neither substantial datasets with fully characterized ground truth, nor simulation programs for realistic 4C-seq data have been published."/jats:p" "/jats:sec" "jats:sec" "jats:title"Results"/jats:title" "jats:p"We conducted a benchmarking study on 66 4C-seq samples from 20 datasets, and developed a novel 4C-seq simulation software, Basic4CSim, to allow for detailed comparisons of 4C-seq algorithms on 50 simulated datasets with 10–120 samples each. Simulations and benchmarking were adapted to address different characteristics of 4C-seq data. Simulated data were compared with published samples to validate simulation settings. We identified differences between 4C-seq algorithms in terms of precision, recall, interaction structure, and run time, and observed general trends. Novel differential pipeline versions of single-sample based 4C-seq algorithms were included in the benchmarking. While no single tool was optimally suited for both near-cis and far-cis, and both single-sample and differential analyses, choosing a high-performing algorithm variant did improve results considerably. For near-cis scenarios, r3Cseq, peakC and FourCSeq offered high precision, while fourSig demonstrated high overall F1 scores in far-cis analyses. Finally, 4C-seq simulations may aid in the development of improved analysis algorithms."/jats:p" "/jats:sec" "jats:sec" "jats:title"Availability and implementation"/jats:title" "jats:p"Basic4CSim is available at https://github.com/walter–ca/Basic4CSim."/jats:p" "/jats:sec" "jats:sec" "jats:title"Supplementary information"/jats:title" "jats:p"Supplementary data are available at Bioinformatics online."/jats:p" "/jats:sec

Document type: Article

Analysis of Walking-Edge Effect in Train Station Evacuation Scenarios: A Sustainable Transportation Perspective

Scipedia content — Mon, 15 Feb 2021 12:24:06 +0100

Due to the highly developed rail transit over the past decades, the phenomena of complex individual self-organized behaviors and mass crowd dynamics have become a great concern in the train station. In order to understand passengers&rsquo

walking-edge effect and analyze the relationship between the layout and sustainable service abilities of the train station, a heuristics-based social force model is proposed to elaborate the crowd dynamics. Several evacuation scenarios are implemented to describe the walking-edge effect in a train station with the evacuation efficiency, pedestrian flow, and crowd density map. The results show that decentralizing crowd flow can significantly increase the evacuation efficiency in different scenarios. When the exits are far away from the central axis of the railway station, the walking-edge effect has little influence on the evacuation efficiency. Obstacles can guide the movement of passengers by channelizing pedestrian flows. In addition, a wider side exit of the funnel-shaped corridors can promote walking-edge effect and decrease the pressure among a congested crowd. Besides providing a modified social force model with considering walking-edge effect, several suggestions are put forward for managers and architects of the train station in designing sustainable layouts.

Document type: Article

Optimization Model of Taxi Fleet Size Based on GPS Tracking Data

Scipedia content — Mon, 15 Feb 2021 12:21:28 +0100

reasonable taxi fleet size has a significant impact on the satisfaction of urban traffic demand, the alleviation of urban traffic congestion, and the stability of taxi business groups. Most existing studies measure the overall scale by using macro indices, and few studies are from the micro level. To meet the transportation demand for taxis, mitigating the mismatch between taxi supply and demand, this research proposes an urban taxi fleet size calculating model based on GPS tracking data. Firstly, on the basis of road network segmentation, the probability model of a passenger taxi-taking a road section as a unit is built to evaluate the difficulty of taxi-taking on a road section. Furthermore, a user queuing model is built for the &ldquo

difficult to take a taxi&rdquo

road section in the peak period, and the service mileage required by potential taxi users is calculated. After that, a transportation capacity measurement model is built to estimate the number of taxis required in different time periods, Finally, the income constraint model is used to explain the impact of different vehicle fleet sizes on the income of taxi groups, so as to provide a reference for the determination of the final fleet size. The model is applied to data from Xi&rsquo

an. The calculation results are based on data from May 2014, and show that the scale of taxi demand is about 654&ndash

2237, and after considering the impact of different fleet size increases on income, when the income variation index is limited to 0.10, i.e., the decrease of drivers&rsquo

income will not exceed 10%, an increase of 1286 taxis will be able to meet 66% of the unmet demand in the peak period. The conclusion indicates that the model can effectively calculate the required fleet size and formulate the constraint solutions. This method provided can be considered as a support for formulating the regulation strategy of an urban taxi fleet size.

Document type: Article

Research on the Anti-Disturbance Control Method of Brake-by-Wire Unit for Electric Vehicles

Scipedia content — Mon, 15 Feb 2021 12:18:38 +0100

In order to improve the braking performance of electric vehicles, a novel brake-by-wire actuator based on an electro-magnetic linear motor was designed and manufactured. For the purpose of braking force regulation accuracy and high robust performance, the state observer and the anti-disturbance controller were designed in this paper after describing the actuator structure, braking principle, and mathematical model. The simulation and experimental results showed that the brake actuator responded rapidly, since its response time was only 15 ms. Compared to traditional PID (Proportion Integration Differentiation) methods, the controller proposed in this paper is able to regulate the braking force more precisely and has better anti-disturbance performance, thus the braking process can be accurately controlled according to the driver&rsquo

s demand. The vehicle simulation results showed that the braking distance and braking time were shortened by 12.19% and 15.54%, respectively compared with those of the conventional anti-lock brake system (ABS) in the same braking conditions.

Document type: Article

Numerical and Experimental Validation of the Prototype of A Bio-Inspired Piping Inspection Robot

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

Piping inspection robots are of greater importance for industries such as nuclear, chemical and sewage. Mechanisms having closed loop or tree-like structures can be employed in such pipelines owing to their adaptable structures. A bio-inspired caterpillar type piping inspection robot was developed at Laboratoire des Sciences du Numé

rique de Nantes (LS2N), France. Using DC motors and leg mechanisms, the robot accomplishes the locomotion of a caterpillar in six-steps. With the help of Coulomb&rsquo

s law of dry friction, a static force model was written and the contact forces between legs of robot and pipeline walls were determined. The actuator forces of the DC motors were then estimated under static phases for horizontal and vertical orientations of the pipeline. Experiments were then conducted on the prototype where the peak results of static force analysis for a given pipe diameter were set as threshold limits to attain static phases inside a test pipeline. The real-time actuator forces were estimated in experiments for similar orientations of the pipeline of static force models and they were found to be higher when compared to the numerical model.

Document type: Article

Innovative Scheme for Efficient Freight Movement and Sustainable Emissions Management

Scipedia content — Mon, 15 Feb 2021 12:12:24 +0100

"jats:p"This paper presents and analyses an innovative integrated scheme that aims to rationalize and improve the efficiency of urban freight transport as well as to promote reduced GHG emissions and traffic flows. Emissions management has become critical concern for modern companies and public authorities seeking to reduce carbon emissions and energy consumption from private and commercial heavy vehicle fleets, in line with the political targets of COP21 to COP23. The proposed scheme aims to utilize the current technological advances for efficient transport and logistics operations that regional authorities and companies can use and afford in order to provide competitive traffic management decisions as well as improvements in terms of pollutant emissions reduction. Both public and private stakeholders could interact to monitor and evaluate the impact of traffic policies and measures over time as well as the level of success of their routing strategies. Computational results on different scenarios of an experimental simulation model illustrate the competitiveness of the proposed scheme in an effort to quantify its effect.

Document type: Article

Intergreen Time Calculation Method of Signalized Intersections Based on Safety Reliability Theory: A Monte-Carlo Simulation Approach

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

In China, around ninety percent of the traffic accidents at signalized intersections occur within the signal change intervals, especially during signal change from green to red. Hence, intergreen time (IGT), that is, yellow change interval plus red clearance interval, is of great significance to the safety at signalized intersections. The conventional calculation method of IGT ignores the randomness of drivers’ behaviors, which we believe is an important factor in calculation of IGT. Therefore, the purpose of this research is to investigate a new approach to calculate the IGT based on safety reliability theory. Firstly, a comprehensive literature review concerning the conventional calculation methods of IGT is conducted. Secondly, a theoretical calculation method of IGT based on safety reliability theory is put forward; different from the conventional methods, this model accounts for the uncertainty of driving behavior parameters. Thirdly, a Monte-Carlo simulation is employed to simulate the interactive process of perception-reaction time (PRT) and vehicular deceleration and solve the proposed model. Finally, according to the Monte-Carlo simulation results, the curve clusters describing the relationship between IGT, safety reliability (50%-90%), and intersection width (15-35m) are drawn. Results show that the IGT of a signalized intersection, obeying the normal distribution, is influenced by multiple factors and most sensitive to the PRT and vehicular deceleration. Our method thus successfully incorporates the probabilistic nature of driving behavior. Taking the safety reliability into consideration can provide a more reasonable method to calculate the IGT of signalized intersections.

Document type: Article

Governance in Maritime Passenger Transport: Green Public Procurement of Ferry Services

Scipedia content — Mon, 15 Feb 2021 12:11:53 +0100

Governance is central for sustainability transitions in maritime transport. Norwegian authorities can directly influence developments in maritime transport through green public procurement, and low- or zero-emission technologies have been or are being considered for more than 250 operational ferry and high-speed vessel connections. This study explores practices of green public procurement and investigates procuring authorities and operators&rsquo

perspectives on the efficiency of green public procurement in accelerating sustainability transitions. Through review of calls for tender and interviews with procuring authorities and operators, the study identifies critical issues for green public procurement to accelerate maritime passenger transport toward sustainability. The critical issues are related to either procedural or service delivery issues. Procedural issues refer to timelines with multiple calls on the same time and different views of procurers and operators on the ideal duration of contracts. The most demanding service delivery issues are infrastructure for charging and energy capacity in remote areas where operators have to pre-book energy needs based on rough estimations which in turn increase the tender price.

Document type: Article

Analysis of Multipurpose Container-Passenger Vessel (MCPV) with Detachable Superstructure to Improve Inter-Island Access in Talaud Island

Scipedia content — Mon, 15 Feb 2021 12:11:22 +0100

In 2012, Indonesia developed a National Logistic System (SISLOGAS) framework perceived in Peraturan Presiden (Perpres) No. 26 of 2012, in accordance with the Master Plan of Acceleration and Expansion of Indonesia’s Economic Development (MP3EI). One of the plans consisted in SISLOGAS was the improvement of inter-island transportation networks through Short Sea Shipping (SSS) by providing appropriate vessel which had been applied on Kontainer Masuk Desa program and was previously tested in the Talaud Island as the outermost area of Indonesia. Aside from being located in the outermost Indonesia’s territory, Talaud Island is one of the marine tourism destinations in North Sulawesi, hence this island needs an inter-island crossing vessel when high demand comes (holiday season). However, due to geographical conditions of Talaud Island which only has an average maximum depth of 6m and the underwater volcano Kawio Barat-Mahangetang which emerges from 5.4-8 m above sea level, could be a problematic for larger ships to sail thus small ships for transportation are required. Seeing the needs equally the existing potential, the making of a Multipurpose Container - Passenger Vessel (MCPV) with Detachable Superstructure could be a solution. Alongside specification of length: 20,85 m, breadth: 7 m, draft: 1,4 m, height 2 m and displacement: 181,32 tons, MCPV could carry containers reaching a weight of 77,28 tons and sail in shallow water by using an engine made by YANMAR which could produce 10 knots speed, besides, MCPV is also equipped with detachable container that could be replaced as reauested both for transportation of goods and people. By the existence of MCPV, it is expected to be able to improve inter-island transportation networks.

Document type: Article

RANKING NODES IN COMPLEX NETWORKS: A CASE STUDY OF THE GAUBUS

Scipedia content — Mon, 15 Feb 2021 12:10:50 +0100

Abstract. Connecting points of interest through a well-planned, inter-connected network provides manifold benefits to commuters and service providers. In the South African context, traffic congestion has become of great concern. Given how the South Africa community is slowly developing towards the use of multi-modes of mobility, the Gautrain network can be used to promote the use of multi-modes of mobility, as the Gautrain has been identified as the backbone of mobility within the Gauteng province. Currently commuters have the option to board the Gaubus (a form of Bus Rapid Transit) at their origin points which will take them to the Gautrain station to board the Gautrain. The problem to be solved arises when a commuter wishes to traverse from any bus stop to the Gautrain station, currently he/she only has one option and if the bus network has a shutdown at any point in the network the commuter’s journey will not be possible. In solving this problem, we consider the problem of graph robustness (that is creating new alternative routes to increase node/bus stop connectivity). We initial use Strava data, to identify locations were cyclist prefer to cycle and at what time of day. In graph theory, the nodes with most spreading ability are called influential nodes. Identification of most influential nodes and ranking them based on their spreading ability is of vital importance. Closeness centrality and betweenness are one of the most commonly used methods to identify influential nodes in complex networks. Using the Gaubus network we identify the influential nodes/ bus stops, using the betweenness centrality measure. The results reveal the influential nodes with the highest connectivity as these have cross-connections in the network. Identification of the influential nodes presents an important implication for future planning, accessibility, and, more generally, quality of life.

Document type: Article

Safety Risk Analysis of Unmanned Ships in Inland Rivers Based on a Fuzzy Bayesian Network

Scipedia content — Mon, 15 Feb 2021 12:08:59 +0100

Risk factor identification is the basis for risk assessment. To quantify the safety risks of unmanned vessels in inland rivers, through analysis of previous studies, the safety risk impact factor framework of unmanned vessels in inland rivers is established based on three aspects: the ship aspect, the environmental aspect, and the management and control aspect. Relying on Yangtze River, a fuzzy Bayesian network of the sailing safety risk of unmanned ships in inland rivers is constructed. The proposed safety risk model has considered different operational and environmental factors that affect shipping operations. Based on the fuzzy set theory, historical data, and expert judgments and on previous works are used to estimate the base value (prior values) of various risk factors. The case study assessed the safety risk probabilities of unmanned vessels in Yangtze River. By running uncertainty and sensitivity analyses of the model, a significant change in the likelihood of the occurrence of safety risk is identified, and suggests a dominant factor in risk causation. The research results can provide effective information for analyzing the current safety status for navigation systems of unmanned ships in inland rivers. The estimated safety risk provides early warning to take appropriate preventive and mitigative measures to enhance the overall safety of shipping operations.

Document type: Article

Statistical delay distribution analysis on high-speed railway trains

Scipedia content — Mon, 15 Feb 2021 12:06:33 +0100

The focus of this study is to explore the statistical distribution models of high-speed railway (HSR) train delays. Based on actual HSR operational data, the delay causes and their classification, delay frequency, number of affected trains, and space–time delay distributions are discussed. Eleven types of delay events are classified, and a detailed analysis of delay distribution for each classification is presented. Models of delay probability delay probability distribution for each cause are proposed. Different distribution functions, including the lognormal, exponential, gamma, uniform, logistic, and normal distribution, were selected to estimate and model delay patterns. The most appropriate distribution, which can approximate the delay duration corresponding to each cause, is derived. Subsequently, the Kolmogorov–Smirnov (K–S) test was used to test the goodness of fit of different train delay distribution models and the associated parameter values. The test results show that the distribution of the test data is consistent with that of the selected models. The fitting distribution models show the execution effect of the timetable and help in finding out the potential conflicts in real-time train operations.

Document type: Article

Explanatory Factors for Public Transportation Financing Needs in Spain

Scipedia content — Mon, 15 Feb 2021 12:04:34 +0100

Public transport financing in Spain has generated interest due to the absence of a governing regulatory framework. There is a need for rules that help allocate public subsidies to guarantee the system’s financial sustainability. Without explicit regulation, the current system for assigning and distributing public funding among Spanish cities has become unbalanced. Our goal is to identify the principal factors that explain why urban transport services in different cities require varying levels of public financing. Our results show that variables such as the “passengers,” “number of vehicles,” “number of employees,” “autonomous community deficit”, and “population density” are influencing factors for the needs of public subsidies.

Document type: Article

Solving Traffic Congestion through Street Renaissance: A Perspective from Dense Asian Cities

Scipedia content — Mon, 15 Feb 2021 12:04:19 +0100

Traffic congestion is one of the most vexing city problems and involves numerous factors which cannot be addressed without a holistic approach. Congestion cannot be narrowly tackled at the cost of a city&rsquo

s quality of life. Focusing on transport and land use planning, this paper examines transport policies and practices on both the supply and demand sides and finds that indirect travel demand management might be the most desirable solution to this chronic traffic ailment. The concept of absorption of traffic demand through the renaissance of streets as a way for traffic relief is introduced from two perspectives, with some examples from dense Asian urban contexts to demonstrate this. Firstly, jobs&ndash

housing balance suggests the return of production activities to residential areas and sufficient provision of diverse space/housing options to deal with work-related traffic. The second approach is to promote the street as a multi-activity destination rather than a thoroughfare to access dispersed daily needs, and to advocate more street life to diminish non-commuting traffic. Based on this, suggestions for better transport planning policies are put forward.

Document type: Article

A Rare Event Modelling Approach to Assess Injury Severity Risk of Vulnerable Road Users

Scipedia content — Mon, 15 Feb 2021 12:03:46 +0100

Vulnerable road users (VRUs) represent a large portion of fatalities and injuries occurring on European Union roads. It is therefore important to address the safety of VRUs, particularly in urban areas, by identifying which factors may affect the injury severity level that can be used to develop countermeasures. This paper aims to identify the risk factors that affect the severity of a VRU injured when involved in a motor vehicle crash. For that purpose, a comparative evaluation of two machine learning classifiers&mdash

decision tree and logistic regression&mdash

considering three different resampling techniques (under-, over- and synthetic oversampling) is presented, comparing both imbalanced and balanced datasets. Crash data records were analyzed involving VRUs from three different cities in Portugal and six years (2012&ndash

2017). The main conclusion that can be drawn from this study is that oversampling techniques improve the ability of the classifiers to identify risk factors. On the one hand, this analysis revealed that road markings, road conditions and luminosity affect the injury severity of a pedestrian. On the other hand, age group and temporal variables (month, weekday and time period) showed to be relevant to predict the severity of a cyclist injury when involved in a crash.

Document type: Article

Research on Creating Ecological Highway for Serving Construction of Powerful Transportation Country

Scipedia content — Mon, 15 Feb 2021 12:01:51 +0100

Green transportation is an important feature and intrinsic requirement of a powerful transportation country. Therefore, we shall fully implement the spirit of the 19th National Congress of the Communist Party of China, effectively implement the new development concept, further promote the development of green transportation and serve the construction of a powerful transportation country. An important part of green transportation system is the ecological highway. Therefore, this paper firstly clarifies the concept, connotation and characteristics of ecological highway, defines the whole life cycle of ecological highway construction, that is, different control points in each stage from planning, design, construction to operation, management and maintenance, introduces the built ecological highway in China, proposes the implementation scheme of ecological highway construction based on the specific requirements and key technologies and finally elaborates the safeguard measures for ecological highway construction. Besides, this paper also provides a reference for clarifying the idea and development of ecological highway construction.

Document type: Article

A Real-Time Layer-Adaptive Wavelet Transform Energy Distribution Strategy in a Hybrid Energy Storage System of EVs

Scipedia content — Mon, 15 Feb 2021 12:01:15 +0100

In this paper, a real-time energy distribution strategy is designed by a layer-adaptive wavelet transform algorithm and proposed to meet the load power demand while distributing the high-frequency component to supercapacitors and the low-frequency component to batteries in a hybrid energy storage system. In the proposed method, the number of decomposition layers of wavelet transform corresponding to the load power is adaptively determined by dividing the operation zone of supercapacitors into eight cases to respectively distribute the low frequency component to batteries and the remaining high frequency component to supercapacitors. Firstly, since the state of charge of supercapacitors decreases faster as the decomposition layers increases, the state of charge of supercapacitors is divided into eight cases of operation zones. Secondly, since supercapacitors act as the peak power buffer unit, the corresponding number of decomposition layers is finally adaptively determined according to the operation zone of supercapacitors. An experiment testbed is built to verify the effectiveness of the proposed method. Extensive experiment results show that the proposed method provides a better real-time energy sharing between supercapacitors and batteries when compared with the conditional method.

Document type: Article

Creating reproducible pharmacogenomic analysis pipelines

Scipedia content — Mon, 15 Feb 2021 12:00:20 +0100

BSTRACT"/jats:title""jats:p"The field of Pharmacogenomics presents great challenges for researchers that are willing to make their studies reproducible and shareable. This is attributed to the generation of large volumes of high-throughput multimodal data, and the lack of standardized workflows that are robust, scalable, and flexible to perform large-scale analyses. To address this issue, we developed pharmacogenomic workflows in the Common Workflow Language to process two breast cancer datasets in a reproducible and transparent manner. Our pipelines combine both pharmacological and molecular profiles into a portable data object that can be used for future analyses in cancer research. Our data objects and workflows are shared on Harvard Dataverse and Code Ocean where they have been assigned a unique Digital Object Identifier, providing a level of data provenance and a persistent location to access and share our data with the community.

Document type: Preprint

A Study of Regular and Irregular Neutrosophic Graphs with Real Life Applications

Scipedia content — Mon, 15 Feb 2021 11:59:21 +0100

Fuzzy graph theory is a useful and well-known tool to model and solve many real-life optimization problems. Since real-life problems are often uncertain due to inconsistent and indeterminate information, it is very hard for an expert to model those problems using a fuzzy graph. A neutrosophic graph can deal with the uncertainty associated with the inconsistent and indeterminate information of any real-world problem, where fuzzy graphs may fail to reveal satisfactory results. The concepts of the regularity and degree of a node play a significant role in both the theory and application of graph theory in the neutrosophic environment. In this work, we describe the utility of the regular neutrosophic graph and bipartite neutrosophic graph to model an assignment problem, a road transport network, and a social network. For this purpose, we introduce the definitions of the regular neutrosophic graph, star neutrosophic graph, regular complete neutrosophic graph, complete bipartite neutrosophic graph, and regular strong neutrosophic graph. We define the d m - and t d m -degrees of a node in a regular neutrosophic graph. Depending on the degree of the node, this paper classifies the regularity of a neutrosophic graph into three types, namely d m -regular, t d m -regular, and m-highly irregular neutrosophic graphs. We present some theorems and properties of those regular neutrosophic graphs. The concept of an m-highly irregular neutrosophic graph on cycle and path graphs is also investigated in this paper. The definition of busy and free nodes in a regular neutrosophic graph is presented here. We introduce the idea of the &mu

-complement and h-morphism of a regular neutrosophic graph. Some properties of complement and isomorphic regular neutrosophic graphs are presented here.

Document type: Article

A number-based inventory of size-resolved black carbon particle emissions by global civil aviation

Scipedia content — Mon, 15 Feb 2021 11:58:46 +0100

With the rapidly growing global air traffic, the impacts of the black carbon (BC) in the aviation exhaust on climate, environment and public health are likely rising. The particle number and size distribution are crucial metrics for toxicological analysis and aerosol-cloud interactions. Here, a size-resolved BC particle number emission inventory was developed for the global civil aviation. The BC particle number emission is approximately (10.9 ± 2.1) × 1025 per year with an average emission index of (6.06 ± 1.18) × 1014 per kg of burned fuel, which is about 1.3% of the total ground anthropogenic emissions, and 3.6% of the road transport emission. The global aviation emitted BC particles follow a lognormal distribution with a geometric mean diameter (GMD) of 31.99 ± 0.8 nm and a geometric standard deviation (GSD) of 1.85 ± 0.016. The variabilities of GMDs and GSDs for all flights are about 4.8 and 0.08 nm, respectively. The inventory provides new data for assessing the aviation impacts.

Size-resolved Black Carbon (BC) particle number emission inventory is not available for global civil aviation. Here the authors converted BC mass emission inventory into number emission inventory and found that aviation BC number emission contributes to 1.3% of total ground anthropogenic emissions and 3.6% on global average.

Document type: Article