Scipedia: Documents published in 2016

Development and transport implications of automated vehicles in the Netherlands: Scenarios for 2030 and 2050

Scipedia content — Tue, 16 Feb 2021 10:30:05 +0100

utomated driving technology is emerging. Yet, little is known in the literature about when automated vehicles will reach the market, how penetration rates will evolve and to what extent this new transport technology will affect transport demand and planning. This study uses scenario analysis to identify plausible future development paths of automated vehicles in the Netherlands and to estimate potential implications for traffic, travel behaviour and transport planning on a time horizon up to 2030 and 2050. The scenario analysis was performed through a series of three workshops engaging a group of diverse experts. Sixteen key factors and five driving forces behind them were identified as critical in determining future development of automated vehicles in the Netherlands. Four scenarios were constructed assuming combinations of high or low technological development and restrictive or supportive policies for automated vehicles (AV ...in standby, AV ...in bloom, AV ...in demand, AV ...in doubt). According to the scenarios, fully automated vehicles are expected to be commercially available between 2025 and 2045, and to penetrate the market rapidly after their introduction. Penetration rates are expected to vary among different scenarios between 1% and 11% (mainly conditionally automated vehicles) in 2030 and between 7% and 61% (mainly fully automated vehicles) in 2050. Complexity of the urban environment and unexpected incidents may influence development path of automated vehicles. Certain implications on mobility are expected in all scenarios, although there is great variation in the impacts among the scenarios. Measures to curb growth of travel and subsequent externalities are expected in three out of the four scenario

Laboratory and field tests on photo-electric probes and ultrasonic Doppler flow switch for remote control of turbidity and flowrate of a water-sand mixture flow

Scipedia content — Tue, 16 Feb 2021 10:27:50 +0100

The paper describes the experimental apparatus and field tests carried on to remotely control through non-invasive and non-intrusive instruments turbidity and flowrate of a water-sand mixture flow conveyed by a pipeline. The mixture flow was produced by an innovative plant for seabed management. The turbidity was monitored by thru-beam infra-red photo-electric sensors, while flowrate was monitored by an ultrasonic Doppler flow switch. In a first phase, a couple of photo-electric sensors and a mechanical flow switch were preliminary tested in laboratory to verify installations concerns and measurement repeatability and precision. After preliminary test completion, photo-electric sensors and mechanical flow switch were installed in the real scale plant. Since the mechanical flow switch did not reach high reliability, an ultrasonic Doppler flow switch was identified and tested as alternative. Then, two couple of photo-electric sensors and ultrasonic Doppler flow switch were installed and tested on two pipelines of the plant. Turbidity and minimum flow signals produced by the instruments were integrated in the PLC logic for the automatic management of the plant. The paper also shows how ultrasonic Doppler flow switch measurement repeatability was negatively affected by the presence of the other ultrasonic Doppler flow switch working in a close pipeline and installed inside a steel casing.

Weakest link or strongest node? : Comparing governance strategies for inland ports in transnational European corridors

Scipedia content — Tue, 16 Feb 2021 10:26:55 +0100

Inland ports are becoming more important in enhancing hinterland accessibility of deep-sea ports. Their increasing size and number can however also pose a threat to quality of life in adjacent urban regions, for spatial conflicts between port and urban functions may arise. Therefore, inland port governance strategies are needed. The aim of this paper is to reflect on the findings of an international comparison of municipal governance strategies for inland port development in four different countries along the Rhine–Alpine Corridor. Our findings reflect the difficult position of inland ports relative to urban functions within a densely populated corridor. Sufficient capacity is needed to prevent the occurrence of bottlenecks on links and in nodes, which could limit flows on other parts of the corridor. Increasing inland port capacity should however also be aligned with policy measures in urban regions, to avoid the overlapping of inland port and urban functions which could lead to mutually exclusive land-uses. This poses challenges in terms of inland port governance. We observe that cases in which the port and urban administrations open up the policy process to relevant private stakeholders and the civil society, integrated governance strategies for inland port development are more likely to emerge.

Crowdsensing-based transportation services — An analysis from business model and sustainability viewpoints

Scipedia content — Tue, 16 Feb 2021 10:22:31 +0100

Traffic and transportation are ongoing digitalisation. Travellers always carry smartphones everywhere they go. Smartphone-based crowdsensing can be used to collect and aggregate traffic information for services that contribute to smoother and more sustainable transportation and traffic — but only if the business model is profitable in the long-term. We analyse two existing crowdsensing services in traffic and transportation context (Waze, Moovit) and one being developed (TrafficSense) using findings from business model (two-sided markets; data use), crowdsensing (technical overview, participant incentives), and transportation (efficiency, sustainable urban transportation) literature. Waze may alleviate traffic congestion by helping its millions of users to avoid traffic jams. Moovit makes public transport more attractive by making it easier and smoother to use for travellers. TrafficSense service is developed in a research project. It uses crowdsensing to learn regular, multimodal routes of travellers. The information can be used to predict the general traffic and congestion levels based on the predicted intents of the crowd of travellers. Our contribution is to combine distinct but complementary viewpoints from two-sided markets, business models, crowdsensing, and transportation research to analyse the potential business and sustainability impacts of the emerging crowdsensing-based smart transportation services.

Mobilities, Futures & the City: repositioning discourses – changing perspectives – rethinking policies

Scipedia content — Tue, 16 Feb 2021 10:17:01 +0100

The future of cities and regions will be strongly shaped by the mobilities of people, goods, modes of transport, waste and information. In many ways, the ‘why and ‘for what’ often get lost in discourses on planning and designing mobilities. The predominant planning paradigm still conceptualizes the future of cities and mobilities as a matter of rather more efficient technologies than of social cohesion, integration and connectivity. Sustainable mobility needs the mobilities of ideas and concepts and the reflexivity of policies. Communicative planning theory and the ‘argumentative turn’ have given significant attention to these shifts in societies’ discursive patterns and structures. For making up powerful and strong visions and policies for sustainable cities, ‘collaborative storytelling’ plays a key role. The theoretical outset for the research project ‘Mobilities, Futures & the City’, which grounds this article, was to explicitly provide an intersection for reflexivity, interdisciplinarity and e...

Modelling and Simulation of Wildland Fire in the Framework of the Level Set Method

Scipedia content — Tue, 16 Feb 2021 10:15:15 +0100

mong the modelling approaches that have been proposed for the simulation of wildfire propagation, two have gained considerable attention in recent years: the one based on a reaction-diffusion equation, and the one based on the level set method. These two approaches, traditionally seen in competition, do actually lead to similar equation models when the level set method is modified taking into account random effects as those due to turbulent hot air transport and fire spotting phenomena. The connection between these two approaches is here discussed and the application of the modified level set method to test cases of practical interest is shown.

Integrated model for battery Electric Vehicles with energy harvesting active suspension system

Scipedia content — Tue, 16 Feb 2021 10:13:58 +0100

This paper presents an integrated vehicle model to simulate simultaneously the driver, powertrains, chassis, body, road condition, vehicle dynamics and the Active Suspension (AS) system with/without an energy harvesting module. The developed model is used to investigate the ride comfort and influences of energy harvesting AS system on the total energy consumption of battery Electric Vehicles (EVs) relative to EVs with a passive suspension system. Preliminary simulation results show that compared to EVs with a passive suspension system, the ones with AS system improve ride comfort, up to 31% reduction of the vehicle body acceleration RMS value, with an expense of higher energy consumption. This expense can be reduced to about 2.8% when using an energy harvesting AS system. Simulation results also demonstrate that the available energy for recuperation during the AS system operation is significant in relation to the regenerative braking energy of the propulsion system, up to approx. 70% on bumpy road surfaces.

Statistical characterization of deviations from planned flight trajectories in air traffic management

Scipedia content — Tue, 16 Feb 2021 10:08:19 +0100

Understanding the relation between planned and realized flight trajectories and the determinants of flight deviations is of great importance in air traffic management. In this paper we perform an in depth investigation of the statistical properties of planned and realized air traffic on the German airspace during a 28 day periods, corresponding to an AIRAC cycle. We find that realized trajectories are on average shorter than planned ones and this effect is stronger during night-time than daytime. Flights are more frequently deviated close to the departure airport and at a relatively large angle to destination. Moreover, the probability of a deviation is higher in low traffic phases. All these evidences indicate that deviations are mostly used by controllers to give directs to flights when traffic conditions allow it. Finally we introduce a new metric, termed difork, which is able to characterize navigation points according to the likelihood that a deviation occurs there. Difork allows to identify in a statistically rigorous way navigation point pairs where deviations are more (less) frequent than expected under a null hypothesis of randomness that takes into account the heterogeneity of the navigation points. Such pairs can therefore be seen as sources of flexibility (stability) of controllers traffic management while conjugating safety and efficiency.

Comment: 16 pages; 11 figures; 3 table

A green intermodal service network design problem with travel time uncertainty

Scipedia content — Tue, 16 Feb 2021 10:08:02 +0100

In a more and more competitive and global world, freight transports have to overcome increasingly long distances while at the same time becoming more reliable. In addition, a raising awareness of the need for environmentally friendly solutions increases the importance of transportation modes other than road. Intermodal transportation, in that regard, allows for the combination of different modes in order to exploit their individual advantages. Intermodal transportation networks offer flexible, robust and environmentally friendly alternatives to transport high volumes of goods over long distances. In order to reflect these advantages, it is the challenge to develop models which both represent multiple modes and their characteristics (e.g., fixed-time schedules and routes) as well as the transhipment between these transportation modes. In this paper, we introduce a Green Intermodal Service Network Design Problem with Travel Time Uncertainty (GISND-TTU) for combined offline intermodal routing decisions of multiple commodities. The proposed stochastic approach allows for the generation of robust transportation plans according to different objectives (i.e., cost, time and greenhouse gas (GHG) emissions) by considering uncertainties in travel times as well as demands with the help of the sample average approximation method. The proposed methodology is applied to a real-world network, which shows the advantages of stochasticity in achieving robust transportation plans.

A random utility model for park & carsharing services and the pure preference for electric vehicles

Scipedia content — Tue, 16 Feb 2021 10:03:53 +0100

Most of the existing Carsharing business models mainly rely on gasoline vehicles and diesel vehicles, but in recent years there has been a significant increase in hybrid electric vehicles (HEVs) and a resurgence in electric vehicles (EVs). Within this framework, this paper investigates and models the choice to switch from a private car trip to a carsharing service available in peripheral parks as well as the propensity to choose an electric vehicle for such a service. In particular, three issues are addressed: (i) investigating and modelling the propensity to choose carsharing as a transport alternative within a neighbourhood residential carsharing business model; (ii) estimating the effect of also having an EV option available; (iii) measuring the “pure preference”, if any, in using electric vehicles over traditional ones, in a context excluding factors that may bias such users preference (e.g. purchase price, energy costs, recharging facilities etc). The analyses are based on a stated preferences survey undertaken on 600 car drivers entering the city centre of Salerno (Southern Italy), and on the estimation of a binomial Logit model with serial correlation. Results allow an interpretation of the main determinants of the short-term choice of carsharing services (i.e. without any car-ownership changes), give general behavioural insights, make it possible to quantify the “pure preference” for EV and the demand elasticity with regard to different pricing strategies of the carsharing services.

Comparison of fatal motor vehicle accidents at passive and active railway level crossings in Finland

Scipedia content — Tue, 16 Feb 2021 10:00:47 +0100

The study compares accidents at passive and active railway level crossings, and both immediate and background risk factors are considered. Passive railway level crossings have no warning devices, although there might be a static warning sign. Active level crossings are equipped with automatic devices warning road users of approaching trains. The data covers all fatal motor vehicle accidents at level crossings in Finland during the years 1991 to 2011 (n = 142). All these accidents have previously been investigated in detail by Road Accident Investigation Teams. Most of the accidents took place at passive level crossings. Compared to active level crossings, and related to the number of fatal accidents, passive level crossings have become proportionally more risky during the study period. Almost all the immediate risk factors in the accidents were of the human error type. Observation errors on the part of the road user were typical at passive level crossings, and risk taking at active level crossings. The environment did not support safe crossing in most of the accidents at passive level crossings. The speed limits of both the road and rail were high, visibility was insufficient, and the level crossing was often situated uphill. Active warning devices are effective in preventing accidents due to road user errors. Equipping the most dangerous passive level crossings with warning devices – low cost or conventional – would increase safety. Alternatively, some level crossings could be removed altogether. A minimum requirement is that the environmental factors at passive level crossings support safe crossing.

Quantifying the increase in lateral capacity of monopiles in sand due to cyclic loading

Scipedia content — Tue, 16 Feb 2021 09:50:56 +0100

The contribution of this paper is a simple method to predict the higher moment capacity of a monopile in dense silica sand after drained cyclic loading. The method accounts for the effect of cyclic load magnitude, symmetry and number of cycles, and is calibrated against a series of single gravity and centrifuge tests. The agreement between the model test data and the predictions is typically within 2%. Application of the method shows that the moment capacity of a monopile in dense sand, for the conditions tested here, is up to 36% higher after cycling. This contrasts with a 10% reduction that would be predicted using the existing industry standard p–y approach for cyclic loading in sand.

Study of a New Quick-Charging Strategy for Electric Vehicles in Highway Charging Stations

Scipedia content — Mon, 15 Feb 2021 12:32:00 +0100

To solve the problem, because of which conventional quick-charging strategies (CQCS) cannot meet the requirements of quick-charging for multiple types of electric vehicles (EV) on highways where vehicle inflow is excessive, this paper proposed a new quick-charging strategy (NQCS) for EVs: on the premise of not affecting those EVs being charged, the remaining power of the quick-charging pile with multiple power output interfaces is used to provide a synchronous charging service for EVs waiting in the queue. To verify the effectiveness of this strategy, a power distribution model of charging pile and a queuing model of charging station (CS) were constructed. In addition, based on an actual highway service area where vehicle inflow is excessive during the simulation period (0:00–24:00), charging situations of CQCS and NQCS were respectively simulated in a charging station (CS), with different number of chargers, by basic queuing algorithm and an improved queuing algorithm. The simulation results showed that when the relative EV inflow is excessive, compared to CQCS, NQCS not only can reduce user waiting time, charging time, and stay time, but also can improve the utilisation rate of charging infrastructure and service capacity of CS and reduce the queue length of CS. At the same time, NQCS can reduce the impact on the power grid. In addition, in NQCS, the on-demand power distribution method is more efficient than the average power distribution method. Therefore, NQCS is more suitable for quick-charging for multiple types of EVs on highways where vehicle inflow is excessive.

Document type: Article

Green Supply Chain Network Design with Economies of Scale and Environmental Concerns

Scipedia content — Mon, 15 Feb 2021 12:31:20 +0100

This study considers a design problem in the supply chain network of an assembly manufacturing enterprise with economies of scale and environmental concerns. The study aims to obtain a rational tradeoff between environmental influence and total cost. A mixed-integer nonlinear programming model is developed to determine the optimal location and size of regional distribution centers (RDCs) and the investment of environmental facilities considering the effects of economies of scale and CO"jats:sub"2"/jats:sub" emission taxes. Numerical examples are provided to illustrate the applications of the proposed model. Moreover, comparative analysis of the related key parameters is conducted (i.e., carbon emission tax, logistics demand of customers, and economies of scale of RDC), to explore the corresponding effects on the network design of a green supply chain. Moreover, the proposed model is applied in an actual case—network design of a supply chain of an electric meter company in China. Findings show that (i) the optimal location of RDCs is affected by the demand of customers and the level of economies of scale and that (ii) the introduction of CO"jats:sub"2"/jats:sub" emission taxes will change the structure of a supply chain network, which will decrease CO"jats:sub"2"/jats:sub" emissions per unit shipment.

Document type: Article

Risk Assessment of Distribution Networks Considering the Charging-Discharging Behaviors of Electric Vehicles

Scipedia content — Mon, 15 Feb 2021 12:26:04 +0100

Electric vehicles (EVs) have received wide attention due to their higher energy efficiency and lower emissions. However, the random charging and discharging behaviors of substantial numbers of EVs may lead to safety risk problems in a distribution network. Reasonable price incentives can guide EVs through orderly charging and discharging, and further provide a feasible solution to reduce the operational risk of the distribution network. Considering three typical electricity prices, EV charging/discharging load models are built. Then, a Probabilistic Load Flow (PLF) method using cumulants and Gram-Charlier series is proposed to obtain the power flow of the distribution network including massive numbers of EVs. In terms of the risk indexes of node voltage and line flow, the operational risk of the distribution network can be estimated in detail. From the simulations of an IEEE-33 bus system and an IEEE 69-bus system, the demonstrated results show that reasonable charging and discharging prices are conducive to reducing the peak-valley difference, and consequently the risks of the distribution network can be decreased to a certain extent.

Document type: Article

Propulsive Qualities of Catamaran Vessels

Scipedia content — Mon, 15 Feb 2021 12:20:42 +0100

During the last decade the civil and military applications of catamaran vessels have developed rapidly. Their particular area of proliferation is the short sea shipping where their power, economy, habitability and behavior have provided them a market niche. The rapid market growth ha caused catamarans to experience design modifications regarding size, speed, cargo diversity (passengers, vehicles, containers). The purpose of this article is to show the work developed by the El Pardo Hydrodynamic Experiences Channel (CEHIPAR) regarding the propulsive qualities of catamaran vessels. This work is the result of the need expressed by the Ministry of Defense for provision of technical assistance and scientific research for an I+D program that established more adequate program parameters for a catamaran-type vessel from the propulsive point of view, in relation to its size and shape, so that it has the adequate information and trustworthiness when suggesting a vessel of this type as an alternative to other platforms, always within the scope of application of patrol-type or quick-attack-type vessels.

Document type: Article

The paradox of public acceptance of bike sharing in Gothenburg

Scipedia content — Mon, 15 Feb 2021 12:19:56 +0100

Bike sharing is one of the most promising urban planning interventions to facilitate an all-necessary transition towards a more sustainable transport paradigm. Regardless of the fact that hundreds of schemes run in more than 50 countries worldwide, bike sharing is still moderately investigated by research. This paper reports on a primarily quantitative study of 558 responses that was set to frame attitudes reflecting public acceptance towards the rapidly expanding bike-sharing scheme in Gothenburg (Styr & Ställ), in an attempt to identify the ‘formula for success’. The respondents generally believed that Styr & Ställ is a pro-environmental, inexpensive and healthy transport mode, which complements the city’s public transport services and promotes a more human-friendly identity for Gothenburg.\\ud Even the respondents that self-reported a small (or no) likelihood to use bike sharing were positive towards the scheme. This means that they recognise that bike sharing has a significant pro-social potential and is not a system favouring a particular road-user segment over others that might not be interested or able to use it. The fact that the majority of the respondents do not Bike sharing is one of the most promising urban planning interventions to facilitate an all-necessary transition\\ud towards a more sustainable transport paradigm. Regardless of the fact that hundreds of schemes run in more than 50 countries worldwide, bike sharing is still moderately investigated by research. This paper reports on a primarily\\ud quantitative study of 558 responses that was set to frame attitudes reflecting public acceptance towards the rapidly expanding bike-sharing scheme in Gothenburg (Styr & Ställ), in an attempt to identify the ‘formula for success’. The respondents generally believed that Styr & Ställ is a pro-environmental, inexpensive and healthy transport mode, which complements the city’s public transport services and promotes a more human-friendly identity for Gothenburg. Even the respondents that self-reported a small (or no) likelihood to use bike sharing were positive towards the scheme. This means that they recognise that bike sharing has a significant pro-social potential and is not a system favouring a particular road-user segment over others that might not be interested or able to use it. The fact that the majority of the respondents do not use the scheme and yet its popularity is still vast indicates that there is much potential for more use in real terms.

Document type: Article

Radiological Assessment of Atmospheric Release from Tehran Research Reactor during Normal Operation by Using Pc-Cream Code

Scipedia content — Mon, 15 Feb 2021 12:11:38 +0100

In this work, radiological assessment of atmospheric release from Tehran’s Research Reactor (TRR) stack and assessment of public exposures under normal operation has been studied. To perform tasks mentioned above, Pc-Cream computer code which simulates Gaussian Dispersion air transport plume model as well as laboratory analysis of the soil and leaves samples and TLD (Thermo Luminescent Dosimeter) monitoring around the TRR site was used. Results of the Pc-Cream code showed that the annual committed and external dose received by the individual in the vicinity of the reactor is below the regulatory limit. Also, the results of laboratory analysis of available radionuclides in the soil and leaves samples showed that the concentrations are close to the background (K40=635, Th232=28, Cs137=0.29 up to 28.82, Ra226=25 (Bq[1]/Kg) in soil and K40=457, Be7≈70 (Bq/Kg) in leaves) and confirm the code results. The monitored dose values of the TLD detectors were positioned around the reactor within 500 m radius shows that the background dose in vicinity of TRR (113 μSv up to 150 μSv) is consistent with the background dose in Tehran province (125 μSv).

Document type: Article

Route Optimization of Pipeline in Gas-Liquid Two-Phase Flow Based on Genetic Algorithm

Scipedia content — Mon, 15 Feb 2021 12:07:40 +0100

This paper describes the problems in route optimization of two-phase pipelines. Combining the hydraulic calculation with route optimization theory, this paper establishes an automatic route optimization model and adopts the general genetic algorithm (gGA) and steady-state genetic algorithm (ssGA) to solve the model, respectively, gets the optimal route, and discusses the influence of parameters setting to the result. This algorithm was applied in determining pipelines routes in coalbed methane gathering and transporting system in Shanxi Province, China. The result shows that the algorithm is feasible, which improves the hydraulic properties by reducing the pressure drop along the line while the pipeline length is still acceptable.

Document type: Article

Value creation of road infrastructure networks: A structural equation approach

Scipedia content — Mon, 15 Feb 2021 12:05:50 +0100

hough road agencies need to provide road infrastructure that is beneficial for road users, little is known about how the activities of the agencies influence the value creation of road infrastructure. From a service-dominant logic perspective, the importance of road maintenance and traffic management activities for the contribution of road infrastructure to the value-creation process of road users is investigated. Road agencies facilitate the value creation of road users by maintaining, upgrading or renewing road infrastructure, the provision of information about the current traffic situation, possible redirection routes in case of traffic jams, and suggestions for appropriate driving behavior. Based on a structured questionnaire, data were collected among motorists in Singapore and analyzed by means of a partial least square modeling approach. The analysis revealed that road cleanliness and road evenness have a significant effect on the experience of road maintenance. Important and significant indicators for the experience of traffic management are the clarity of road signs and the efficiency of traffic redirection. A main conclusion of the research is that for traffic-intensive networks, both road maintenance and traffic management activities are important contributors to the value creation of road infrastructure with a slightly stronger contribution of traffic management activities. Road agencies need to find appropriate maintenance strategies which reduce and coordinate simultaneous maintenance interventions on the network to such an extent that traffic management activities are able to minimize any considerable loss of traffic flow.

Document type: Article

Restart time correlation for core annular flow in pipeline lubrication of high-viscous oil

Scipedia content — Mon, 15 Feb 2021 11:59:04 +0100

One of the fundamental questions that must be addressed in the effective design and operation of pipeline lubrication of heavy oil is; “how much time will be needed to restart a blocked core annular flow (CAF) line after shutdown due to fouling or pump failures”, if the pipe is to be cleaned using water only. In this work, laboratory results of shutdown and restart experiments of high-viscous oil conducted in a 5.5-m-long PVC horizontal pipe with internal diameter of 26 mm are first presented. A new correlation for the prediction of the restart time of a shutdown core annular flow line is then formulated. The predictive capabilities of the correlation are checked against measured restart time and pressure drop evolution data. Somewhat high but still reasonable predictions are obtained. The restart time correlation, together with the associated correlations formulated as well, can be of practical importance during the engineering design of high-viscous oil pipeline transportation facility for predicting restart process.

Document type: Article

Integrated Optimization of Bus Line Fare and Operational Strategies Using Elastic Demand

Scipedia content — Mon, 15 Feb 2021 11:57:10 +0100

An optimization approach for designing a transit service system is proposed. Its objective would be the maximization of total social welfare, by providing a profitable fare structure and tailoring operational strategies to passenger demand. These operational strategies include full route operation (FRO), limited stop, short turn, and a mix of the latter two strategies. The demand function is formulated to reflect the attributes of these strategies, in-vehicle crowding, and fare effects on demand variation. The fare is either a flat fare or a differential fare structure; the latter is based on trip distance and achieved service levels. This proposed methodology is applied to a case study of Dalian, China. The optimal results indicate that an optimal combination of operational strategies integrated with a differential fare structure results in the highest potential for increasing total social welfare, if the value of parameter "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"""mml:mrow""mml:mi"ε"/mml:mi""/mml:mrow""/mml:math" related to additional service fee is low. When this value increases up to more than a threshold, strategies with a flat fare show greater benefits. If this value increases beyond yet another threshold, the use of skipped stop strategies is not recommended.

Document type: Article

Surrogate Safety Analysis of Pedestrian-Vehicle Conflict at Intersections Using Unmanned Aerial Vehicle Videos

Scipedia content — Mon, 15 Feb 2021 11:31:25 +0100

Conflict analysis using surrogate safety measures (SSMs) has become an efficient approach to investigate safety issues. The state-of-the-art studies largely resort to video images taken from high buildings. However, it suffers from heavy labor work, high cost of maintenance, and even security restrictions. Data collection and processing remains a common challenge to traffic conflict analysis. Unmanned Aerial Systems (UASs) or Unmanned Aerial Vehicles (UAVs), known for easy maneuvering, outstanding flexibility, and low costs, are considered to be a novel aerial sensor. By taking full advantage of the bird’s eye view offered by UAV, this study, as a pioneer work, applied UAV videos for surrogate safety analysis of pedestrian-vehicle conflicts at one urban intersection in Beijing, China. Aerial video sequences for a period of one hour were analyzed. The detection and tracking systems for vehicle and pedestrian trajectory data extraction were developed, respectively. Two SSMs, that is, Postencroachment Time (PET) and Relative Time to Collision (RTTC), were employed to represent how spatially and temporally close the pedestrian-vehicle conflict is to a collision. The results of analysis showed a high exposure of pedestrians to traffic conflict both inside and outside the crosswalk and relatively risking behavior of right-turn vehicles around the corner. The findings demonstrate that UAV can support intersection safety analysis in an accurate and cost-effective way.

Document type: Article

Initial Energy Logistics Cost Analysis for Stationary, Quasi-Dynamic, and Dynamic Wireless Charging Public Transportation Systems

Scipedia content — Mon, 15 Feb 2021 11:02:53 +0100

This paper presents an initial investment cost analysis of public transportation systems operating with wireless charging electric vehicles (EVs). There are three different types of wireless charging systems, namely, stationary wireless charging (SWC), in which charging happens only when the vehicle is parked or idle, quasi-dynamic wireless charging (QWC), in which power is transferred when a vehicle is moving slowly or in stop-and-go mode, and dynamic wireless charging (DWC), in which power can be supplied even when the vehicle is in motion. This analysis compares the initial investment costs for these three types of charging systems for a wireless charging-based public transportation system. In particular, this analysis is focused on the energy logistics cost in transportation, which is defined as the cost of transferring and storing the energy needed to operate the transportation system. Performing this initial investment analysis is complicated, because it involves considerable tradeoffs between the costs of batteries in the EV fleet and different kinds of battery-charging infrastructure. Mathematical optimization models for each type of EV and infrastructure system are used to analyze the initial costs. The optimization methods evaluate the minimum initial investment needed to deploy the public transportation system for each type of EV charging solution. To deal with the variable cost estimates for batteries and infrastructure equipment in the current market, a cost-sensitivity analysis is performed. The goal of this analysis is to identify the market cost conditions that are most favorable for each type of wireless charging solution. Furthermore, the cost analysis quantitatively verifies the qualitative comparison of the three different wireless charging types conducted in the previous research.

Document type: Article

Smart Brix—a continuous evolution framework for container application deployments

Scipedia content — Mon, 15 Feb 2021 10:59:19 +0100

Container-based application deployments have received significant attention in recent years. Operating system virtualization based on containers as a mechanism to deploy and manage complex, large-scale software systems has become a popular mechanism for application deployment and operation. Packaging application components into selfcontained artifacts has brought substantial flexibility to developers and operation teams alike. However, this flexibility comes at a price. Practitioners need to respect numerous constraints ranging from security and compliance requirements, to specific regulatory conditions. Fulfilling these requirements is especially challenging in specialized domains with large numbers of stakeholders.Moreover, the rapidly growing number of container images to be managed due to the introduction of new or updated applications and respective components, leads to significant challenges for container management and adaptation. In this paper, we introduce Smart Brix, a framework for continuous evolution of container application deployments that tackles these challenges. Smart Brix integrates andunifies concepts of continuous integration, runtimemonitoring, and operational analytics. Furthermore, it allows practitioners to define generic analytics and compensation pipelines composed of self-assembling processing components to autonomously validate and verify containers to be deployed.We illustrate the feasibility of our approach by evaluating our framework using a case study from the smart city domain. We show that Smart Brix is horizontally scalable and runtime of the implemented analysis and compensation pipelines scales linearly with the number of container application packages. Subjects Adaptive and Self-Organizing Systems, Distributed and Parallel Computing, Software Engineering

Document type: Article

Reconfigurable SRTM System for Road Traffic in Kingdom of Bahrain

Scipedia content — Mon, 15 Feb 2021 10:57:11 +0100

"jats:p"This paper presents reconfigurable hardware architecture for smart road traffic system based on Field Programmable Gate Array (FPGA). The design can be reconfigured for different timing of the traffic signals according to the received and collected data read by the different sensors on the road; the design has been described using VHDL (VHSIC Hardware Description Language). The SRTM (Smart Road Traffic Management) System has some more features that help passenger to avoid traffic jamming by sending the collected information through web/mobile applications to find the best road between the start and destination points, which will be displayed on Google maps, at the same time it will also shows the points of traffic jamming on Google maps. SRTM system can also manage emergency vehicles such as ambulance and fire fighter and also can send snapshots and video streaming for different roads and junctions to show the points of traffic jamming. The design has been simulated and tested using ModelSim PE student edition 10.4. Spartan 3 FPGA starter kit from Xilinx has been used for implementing and testing the design in a hardware level.

Document type: Article

Indicators of sustainable development performance: Case study of European Union countries

Scipedia content — Mon, 15 Feb 2021 10:51:06 +0100

"jats:p" A sustainable development strategy is an essential long-term strategy that aims to bring about a balance of three key policy factors: sustainable economic growth and economic and technological development, sustainable development of society based on social equality, and environmental protection with a rational use of natural resources. The sustainable development strategy is very complex and contains a large number of indicators, so one of the statistical methods that can be used for this complex problem is the I-distance method. It was created as a need to rank countries according to the level of socio-economic development and the problem was how to take advantage of all the indicators in order to calculate a synthetic indicator which would represent the rank. The I-distance method in this paper is used for the ranking of 18 countries of the European Union based on ten indicators that have been selected in accordance with the EU Sustainable Development Strategy. The used headline indicators come from the following areas: socio-economic development, sustainable consumption and production, social inclusion, demographic changes, public health, climate change and energy, sustainable transport, and global partnership. By analysing the initial set of indicators and their correlation coefficients with the found I-distance values, the following most important indicators were found: official development assistance as a share of the gross national income, employment rate of older workers, healthy life years and life expectancy at birth (males), energy consumption of transport relative to GDP etc. Countries that occupied the top three places were Sweden, Luxembourg, and Finland while Croatia, Poland, and Slovenia occupied the last three places.

Document type: Article

Influence of fuel (diesel and biodiesel) features and fleet vehicles transport group of NOx emissions in Curitiba, Paraná, Brazil

Scipedia content — Mon, 15 Feb 2021 10:49:37 +0100

RESUMO: O sistema de transporte coletivo da cidade de Curitiba, no Paraná, é reconhecido pelas suas soluções inovadoras e modelo para o Brasil. Neste trabalho foi analisada a influência do combustível (diesel e biodiesel) e das condições da frota de veículos do transporte coletivo de Curitiba nas emissões de NOx, e essa é uma iniciativa pioneira. Foram selecionados 188 veículos (9,7% do total) com motores de 7 a 12 L, denominados B7R, B10M, B12M e B215RH, e foram realizadas medições de NO e NO2 na saída dos escapamentos. Com relação ao tipo de combustível, as emissões de NO e NO2 para o biodiesel (B100) foram, respectivamente, 37 e 26% superiores aos valores observados com o combustível diesel (S10). Comparando motores B12M com até 3 e 10 anos de operação, as emissões médias de NOx foram próximas de 40% maior. Assim, foi possível observar que os veículos a biodiesel tiveram maior emissão de NOx quando comparados com veículos a diesel, em condições similares de operação e tempo de uso do motor. Entretanto, embora o uso de biodiesel traga vantagens ambientais, como energia renovável, novas tecnologias e dispositivos devem ser desenvolvidos para controlar emissões de NO e NO2 em motores que utilizam esse tipo de combustível. Para trabalhos futuros, os autores recomendam testes em dinamômetro, para simular emissões de NOx em motores a diesel e biodiesel em diferentes condições de carga e regime de rotação do motor. ABSTRACT: The public transportation system in Curitiba, Paraná, Brazil, is recognized by its innovative solutions; and is a model for Brazil. In this work, the influence of fuel (diesel and biodiesel) and the conditions of the public transport vehicle fleet of Curitiba in NOx emissions was assessed, and this is a pioneered initiative. A total of 188 vehicles (9.7% of the total) with engines of 7 and 12 L were selected, named B7R, B10M, B12M and B215RH, and measurements of NO and NO2 were performed in the exhaust output. In relation to the type of fuel, the emissions of NO and NO2 for biodiesel (B100) were, respectively, 37 and 26% superior to the values observed with the fuel diesel (S10). Comparing the engines B12M with up to 3 and 10 years of operation, the average emissions of NOx were close to 40% higher. Thus, it was possible to observe that the biodiesel vehicles had higher NOx emissions when compared with diesel vehicles in similar conditions of operation and engine wear time. Therefore, although the use of biodiesel brings environmental advantages, as renewable fuel, new technologies and devices must be developed to control emissions of NO and NO2 in engines that use this type of fuel. For future works the authors recommend tests on dynamometer to simulate NOx emission in diesel and biodiesel engine in different conditions of charge and engine speed.

Document type: Article

Substantiation of FAC rate and service life estimation under operation control data

Scipedia content — Mon, 15 Feb 2021 10:45:09 +0100

Flow-accelerated corrosion (FAC) wear is the complex mechanism of damage of elements of NPP equipment and pipelines. FAC rate is determined by such factors as corrosion of metal, flow hydrodynamics, geometry of equipment elements and pipelines, applied water chemistry regimes (WCR), duration of operation, chemical composition of the metal, thickness of deposited corrosion product film and others. Approaches to the assessment of FAC rate according to the control data are addressed in the present study. Implemented investigation was aimed at the substantiation of the methodology of calculation of FAC rate. Absence of the methodology for calculation of FAC rate does not allow verification of calculation programs, as well as the use of data of regulatory documents on the minimum permissible thicknesses [1] for evaluating the residual lifetime. Processing of measured data allowed determining the main indexes of FAC process such as the values of wall thinning and thickening, rates of wall thinning and thickening, residual operation time to the moment of reaching the minimum permissible thickness. Reduction of thickness is determined by corrosion of metal and its increase is determined by the formation of deposited film of corrosion products. The process of corrosion products deposition on the internal surfaces of the element proceeds simultaneously with the process of thinning of the wall. Presence of this process results in the situation when the residual lifetime of equipment elements under the conditions of deposition of corrosion products is technically increased. At the same time the real state of the wall under the layer of deposited corrosion products is unknown, as well as the initial wall thickness. In order to bring the calculated results closer to the real situation it is necessary to use substantiated and verified methodology in the calculations of FAC rate according to the data of control measurements. The implemented study allowed suggesting the methodology of calculation of FAC rate taking into account the technological tolerances on the sizes and taking into account the influence of deposits on the initial and minimum thicknesses. Safety factor was also introduced for calculating the residual lifetime which is taken into account in the international practices because of the same reason. Introduction of correction coefficients allows enhancing the conservatism of calculations of residual lifetime characteristics by approximately 2.5 times compared with calculations performed on the base of nominal thickness.

Document type: Article

A benchmark for RNA-seq quantification pipelines

Scipedia content — Mon, 15 Feb 2021 10:44:20 +0100

Obtaining RNA-seq measurements involves a complex data analytical process with a large number of competing algorithms as options. There is much debate about which of these methods provides the best approach. Unfortunately, it is currently difficult to evaluate their performance due in part to a lack of sensitive assessment metrics. We present a series of statistical summaries and plots to evaluate the performance in terms of specificity and sensitivity, available as a R/Bioconductor package (http://bioconductor.org/packages/rnaseqcomp). Using two independent datasets, we assessed seven competing pipelines. Performance was generally poor, with two methods clearly underperforming and RSEM slightly outperforming the rest. Electronic supplementary material The online version of this article (doi:10.1186/s13059-016-0940-1) contains supplementary material, which is available to authorized users.

Document type: Article

Querying and Extracting Timeline Information from Road Traffic SensorData

Scipedia content — Mon, 15 Feb 2021 10:43:29 +0100

The escalation of traffic congestion in urban cities has urged many countries to use intelligent transportation system (ITS) centers to collect historical traffic sensor data from multiple heterogeneous sources. By analyzing historical traffic data, we can obtain valuable insights into traffic behavior. Many existing applications have been proposed with limited analysis results because of the inability to cope with several types of analytical queries. In this paper, we propose the QET (querying and extracting timeline information) system—a novel analytical query processing method based on a timeline model for road traffic sensor data. To address query performance, we build a TQ-index (timeline query-index) that exploits spatio-temporal features of timeline modeling. We also propose an intuitive timeline visualization method to display congestion events obtained from specified query parameters. In addition, we demonstrate the benefit of our system through a performance evaluation using a Busan ITS dataset and a Seattle freeway dataset.

Document type: Article

Relieving the Impact of Transit Signal Priority on Passenger Cars through a Bilevel Model

Scipedia content — Mon, 15 Feb 2021 10:43:12 +0100

Transit signal priority (TSP) is an effective control strategy to improve transit operations on the urban network. However, the TSP may sacrifice the right-of-way of vehicles from side streets which have only few transit vehicles; therefore, how to minimize the negative impact of TSP strategy on the side streets is an important issue to be addressed. Concerning the typical mixed-traffic flow pattern and heavy transit volume in China, a bilevel model is proposed in this paper: the upper-level model focused on minimizing the vehicle delay in the nonpriority direction while ensuring acceptable delay variation in transit priority direction, and the lower-level model aimed at minimizing the average passenger delay in the entire intersection. The parameters which will affect the efficiency of the bilevel model have been analyzed based on a hypothetical intersection. Finally, a real-world intersection has been studied, and the average vehicle delay in the nonpriority direction decreased 11.28 s and 22.54 s (under different delay variation constraint) compared to the models that only minimize average passenger delay, while the vehicle delay in the priority direction increased only 1.37 s and 2.87 s; the results proved the practical applicability and efficiency of the proposed bilevel model.

Document type: Article

Turnout Fault Diagnosis through Dynamic Time Warping and Signal Normalization

Scipedia content — Mon, 15 Feb 2021 10:42:27 +0100

Turnout is one key fundamental infrastructure in the railway signal system, which has great influence on the safety of railway systems. Currently, turnout fault diagnoses are conducted manually in China; engineers are obliged to observe the signals and make problem solving decisions. Thus, the accuracies of fault diagnoses totally depend on the engineers’ experience although massive data are produced in real time by the turnout microcomputer-based monitoring systems. This paper aims to develop an intelligent diagnosis method for railway turnout through Dynamic Time Warping (DTW). We firstly extract the features of normal turnout operation current curve and normalize the collected turnout current curves. Then, five typical fault reference curves are ascertained through the microcomputer-based monitoring system, and DTW is used to identify the turnout current curve fault through test data. The analysis results based on the similarity data indicate that the analyzed five turnout fault types can be diagnosed automatically with 100% accuracy. Finally, the benefits of the proposed method and future research directions were discussed.

Document type: Article

REVISIÓN DE LA LITERATURA DEL PROBLEMA DE RUTEO DE VEHÍCULOS EN UN CONTEXTO DE TRANSPORTE VERDE

Scipedia content — Mon, 15 Feb 2021 10:38:06 +0100

In the efficient management of the supply chain the optimal management of transport of consumables and finished products appears. The costs associated with transport have direct impact on the final value consumers must pay, which in addition to requiring competitive products also demand that they are generated in environmentally friendly organizations. Aware of this reality, this document is intended to be a starting point for Master's and Doctoral degree students who want to work in a line of research recently proposed: green routing. The state of the art of the vehicle routing problem is presented in this paper, listing its variants, models and methodologies for solution. Furthermore, the proposed interaction between variants of classical routing problems and environmental effects of its operations, known in the literature as Green-VRP is presented. The goal is to generate a discussion in which mathematical models and solution strategies that can be applied within organizations that consider within their objectives an efficient and sustainable operation are posed. En el gerenciamiento eficiente de la cadena de suministro aparece la gestión óptima del transporte de insumos y productos terminados. Los costos asociados al transporte tienen impacto directo sobre el valor final que deben pagar los consumidores, que además de requerir productos competitivos también exigen que los mismos sean generados en organizaciones amigables con el medioambiente. Consientes de esa realidad este documento pretende ser un punto de partida para estudiantes de maestría y doctorado que quieran trabajar en una línea de investigación propuesta recientemente: el ruteo verde. En este trabajo se muestra un estado del arte del problema de ruteo de vehículos, enumerando sus variantes, modelos y metodologías de solución. Además, se presenta la interacción que se ha propuesto entre variantes clásicas de los problemas de ruteo y los efectos ambientales de su operación, denominados en la literatura como Green-VRP. El objetivo es generar una discusión donde se planteen modelos matemáticos y estrategias de solución que puedan ser aplicadas en organizaciones que consideren dentro de sus objetivos una operación eficiente y sustentable.

Document type: Article

Intensive travel time: an obligation or a choice? : Intensive travel time: an obligation or a choice?Joly, I., Vincent-Geslin, S.European Transport Research Review, vol. 8, n° 1, pp. 1-14, February, 2016 http://link.springer.com/article/10.1007%2Fs12544-016-0195-7

Scipedia content — Mon, 15 Feb 2021 10:29:47 +0100

International audience; This paper explores what prompts some individuals to spend a significant amount of time travelling. In the literature, travel time tends to be regarded as useless, unproductive time and, in some cases, as the worst time of the day. The actual behaviour of intensive travellers challenges this view of travel time. A mixed approach that combines quantitative and qualitative methodologies was adopted. A survival analysis of daily travel time in eight European cities gives a quantitative definition of intensive travellers. Qualitative interviews with intensive travellers explore the various dimensions of choice and/or obligation that are responsible for these extreme daily travel times. The results show that roughly 20 % of the individuals in the sample for each city have long travel times (more than 100 min a day). The quantitative analysis also suggests that the behaviour of these individuals is atypical and cannot be explained solely by the characteristics that are considered in standard travel surveys. A qualitative sociological approach supplements the quantitative approach and illustrates that the allocation of travel time is not only determined by the activity pursued at the destination or the mode of transport but also by other factors such as personal beliefs and the perception of travel time. The positive perception of travel time as time to be used constructively or enjoyed influences the decision to travel intensively and, above all, contributes to its long-term acceptability. A number of political issues depend on travel behaviour and therefore, to some extent, on time management. New patterns of behaviour with regard to time management help explain the expansion in the range of individual travel.

Document type: Article

Formal specification and analysis of take-off procedure using VDM-SL

Scipedia content — Mon, 15 Feb 2021 10:27:50 +0100

traffic management system is a complex adaptive and safety critical system which requires considerable attention for its modelling and verification. Currently Air traffic control (ATC) systems are heavily dependent upon human intervention at airport causing accidents and delays because of failure of communication. The purpose of this study is to develop, plan, manage and verify aircrafts movement procedures at the airport surface that prevent delays and collisions. The airport surface is decomposed into blocks and represented by the graph relation. The state space of the system is described by identifying all the possible components of the system. The ground and local controls monitor queues of the aircrafts moving from taxiway to take-off. It is insured that once an aircraft is inserted into a queue, it is eventually removed from it after the next queue has become available. The take-off procedure is provided using graph theory and Vienna Development Method Specification Language (VDM-SL) and analyzed using VDM-SL toolbox. Formal specification of graph-based model, taxiways, aircrafts, runways and controllers is provided in static part of the model. The state space analysis describing take-off algorithms is provided by defining optimal paths and possible operations in dynamic model expediting the departure procedure. The model is developed by a series of refinements following the stepwise development approach. The delays at airport surface require effective safety and guidance protocols to control air traffic at the airport. In static model, the safety criteria are described in terms of invariants over the data types carrying critical information. The safety is insured by defining pre/post conditions in description of operations for changing state space of the system. Although the proposed study is focussed more on the safety component, however, the efficiency is not ignored.

Document type: Article

Sustainable Mobility: Longitudinal Analysis of Built Environment on Transit Ridership

Scipedia content — Mon, 15 Feb 2021 10:27:34 +0100

Given the concerns about urban mobility, traffic congestion, and greenhouse gas (GHG) emissions, extensive research has explored the relationship between the built environment and transit ridership. However, the nature of aggregation and the cross-sectional approach of the research rarely provide essential clues on the potential of a transit system as a sustainable mobility option. From the perspective of longitudinal sustainability, this paper develops regression models for rail transit stations in the Los Angeles Metro system. These models attempt to identify the socio-demographic characteristics and land use features influencing longitudinal transit ridership changes. Step-wise ordinary least square (OLS) regression models are used to identify factors that contribute to transit ridership changes. Those factors include the number of dwelling units, employment-oriented land uses such as office and commercial land uses, and land use balance. The models suggest a negative relationship between job and population balance with transit ridership change. They also raise a question regarding the 0.4 km radius commonly used in transit analysis. The models indicate that the 0.4 km radius is too small to capture the significant influence of the built environment on transit ridership.

Document type: Article

Effects of Human-Centered Factors on Crash Injury Severities

Scipedia content — Mon, 15 Feb 2021 10:21:43 +0100

Factors related to drivers and their driving habits dominate the causation of traffic crashes. An in-depth understanding of the human factors that influence risky driving could be of particular importance to facilitate the application of effective countermeasures. This paper sought to investigate effects of human-centered crash contributing factors on crash outcomes. To select the methodology that best accounts for unobserved heterogeneity between crash outcomes, latent class (LC) logit model and random parameters logit (RPL) model were developed. Model estimation results generally show that serious injury crashes were more likely to involve unemployed drivers, no seatbelt use, old drivers, fatigued driving, and drivers with no valid license. Comparison of model fit statistics shows that the LC logit model outperformed the RPL model, as an alternative to the traditional multinomial logit (MNL) model.

Document type: Article

Transportation of dangerous goods in green transport corridors - conclusions from Baltic Sea region

Scipedia content — Mon, 15 Feb 2021 10:18:28 +0100

"jats:p"The Green Corridor concept represents a cornerstone in the development and implementation of integrated and sustainable transport solutions based on trans-nationality, multi-modality and a high involvement of public and private stakeholders, including the political level. Despite the fact that the Green Transport Corridor (GTC) concept is founded on the three dimensions of sustainability with a strong emphasis on environmental aspects, the corridor hubs as well as the whole transport corridors have to find ways to handle and transport dangerous goods by keeping the high sustainability standards."/jats:p" "jats:p"The paper addresses the research questions what kind of economical, ecological and social risks might occur in the context of handling and transportation of dangerous goods in a Green Transport Corridor in the Baltic Sea Region, what consequences they might have on the GTC design and how and with which measures they can be managed. Based on this analysis the development of a comprehensive risk management concept for the handling and transportation of dangerous goods in Green Transport Corridors in the Baltic Sea Region based on Schröder and Prause (2015) will be started. The concept will include practical implications and best practices.

Document type: Article

Will automated vehicles negatively impact traffic flow?

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

With low-level vehicle automation already available, there is a necessity to estimate its effects on traffic flow, especially if these could be negative. A long gradual transition will occur from manual driving to automated driving, in which many yet unknown traffic flow dynamics will be present. These effects have the potential to increasingly aid or cripple current road networks. In this contribution, we investigate these effects using an empirically calibrated and validated simulation experiment, backed up with findings from literature. We found that low-level automated vehicles in mixed traffic will initially have a small negative effect on traffic flow and road capacities. The experiment further showed that any improvement in traffic flow will only be seen at penetration rates above 70%. Also, the capacity drop appeared to be slightly higher with the presence of low-level automated vehicles. The experiment further investigated the effect of bottleneck severity and truck shares on traffic flow. Improvements to current traffic models are recommended and should include a greater detail and understanding of driver-vehicle interaction, both in conventional and in mixed traffic flow. Further research into behavioural shifts in driving is also recommended due to limited data and knowledge of these dynamics.

Document type: Article

Vision-Based Steering Control, Speed Assistance and Localization for Inner-City Vehicles

Scipedia content — Mon, 15 Feb 2021 10:11:56 +0100

utonomous route following with road vehicles has gained popularity in the last few decades. In order to provide highly automated driver assistance systems, different types and combinations of sensors have been presented in the literature. However, most of these approaches apply quite sophisticated and expensive sensors, and hence, the development of a cost-efficient solution still remains a challenging problem. This work proposes the use of a single monocular camera sensor for an automatic steering control, speed assistance for the driver and localization of the vehicle on a road. Herein, we assume that the vehicle is mainly traveling along a predefined path, such as in public transport. A computer vision approach is presented to detect a line painted on the road, which defines the path to follow. Visual markers with a special design painted on the road provide information to localize the vehicle and to assist in its speed control. Furthermore, a vision-based control system, which keeps the vehicle on the predefined path under inner-city speed constraints, is also presented. Real driving tests with a commercial car on a closed circuit finally prove the applicability of the derived approach. In these tests, the car reached a maximum speed of 48 km/h and successfully traveled a distance of 7 km without the intervention of a human driver and any interruption.

The work reported in this paper is the product of several research stages at the Computer Vision Group Universidad Politécnica de Madrid in collaboration with INSIA-UPM and Siemens España S.A. This project is partially funded by the Centre for the Development of Industrial Technology (CDTI). The authors would like to thank the company SIEMENS España S.A. that has made possible the research described in this paper through several contracts and the people at LABIE (INSIA-UPM) for their support.

Peer Reviewed

Document type: Article

Forecasting of taxi times: The case of Barcelona-El Prat airport

Scipedia content — Mon, 15 Feb 2021 10:08:23 +0100

This study computes linear regression models to predict taxi in and out times at Barcelona-El Prat Airport using R software. Taxi time results are given for each stand as a function of the hour of the day. Also, it is analysed how many variables are influencing the time with their relevancy degree. The study has been carried out using airports daily operational data for the months of June, July and August 2013.

Peer Reviewed

Document type: Article

DSRC versus 4G-LTE for Connected Vehicle Applications: A Study on Field Experiments of Vehicular Communication Performance

Scipedia content — Mon, 15 Feb 2021 09:42:49 +0100

Dedicated short-range communication (DSRC) and 4G-LTE are two widely used candidate schemes for Connected Vehicle (CV) applications. It is thus of great necessity to compare these two most viable communication standards and clarify which one can meet the requirements of most V2X scenarios with respect to road safety, traffic efficiency, and infotainment. To the best of our knowledge, almost all the existing studies on comparing the feasibility of DRSC or LTE in V2X applications use software-based simulations, which may not represent realistic constraints. In this paper, a Connected Vehicle test-bed is established, which integrates the DSRC roadside units, 4G-LTE cellular communication stations, and vehicular on-board terminals. Three Connected Vehicle application scenarios are set as Collision Avoidance, Traffic Text Message Broadcast, and Multimedia File Download, respectively. A software tool is developed to record GPS positions/velocities of the test vehicles and record certain wireless communication performance indicators. The experiments have been carried out under different conditions. According to our results, 4G-LTE is more preferred for the nonsafety applications, such as traffic information transmission, file download, or Internet accessing, which does not necessarily require the high-speed real-time communication, while for the safety applications, such as Collision Avoidance or electronic traffic sign, DSRC outperforms the 4G-LTE.

Document type: Article

Disinfection of aircraft

Scipedia content — Fri, 12 Feb 2021 16:17:39 +0100

For infectious diseases caused by highly pathogenic agents (e. g., Ebola/Lassa fever virus, SARS-/MERS-CoV, pandemic influenza virus) which have the potential to spread over several continents within only a few days, international Health Protection Authorities have taken appropriate measures to limit the consequences of a possible spread. A crucial point in this context is the disinfection of an aircraft that had a passenger on board who is suspected of being infected with one of the mentioned diseases. Although, basic advice on hygiene and sanitation on board an aircraft is given by the World Health Organization, these guidelines lack details on available and effective substances as well as standardized operating procedures (SOP). The purpose of this paper is to give guidance on the choice of substances that were tested by a laboratory of Lufthansa Technik and found compatible with aircraft components, as well as to describe procedures which ensure a safe and efficient disinfection of civil aircrafts. This guidance and the additional SOPs are made public and are available as mentioned in this paper.

Document type: Article

Cluster Flow: A user-friendly bioinformatics workflow tool [version 1; referees: 3 approved]

Scipedia content — Fri, 12 Feb 2021 16:10:21 +0100

ns4:p"Pipeline tools are becoming increasingly important within the field of bioinformatics. Using a pipeline manager to manage and run workflows comprised of multiple tools reduces workload and makes analysis results more reproducible. Existing tools require significant work to install and get running, typically needing pipeline scripts to be written from scratch before running any analysis. We present Cluster Flow, a simple and flexible bioinformatics pipeline tool designed to be quick and easy to install. Cluster Flow comes with 40 modules for common NGS processing steps, ready to work out of the box. Pipelines are assembled using these modules with a simple syntax that can be easily modified as required. Core helper functions automate many common NGS procedures, making running pipelines simple. Cluster Flow is available with an GNU GPLv3 license on GitHub. Documentation, examples and an online demo are available at "ns4:ext-link xmlns:ns3="http://www.w3.org/1999/xlink" ext-link-type="uri" ns3:href="http://clusterflow.io""http://clusterflow.io"/ns4:ext-link"."/ns4

Document type: Article

Effectiveness of two cognitive training programs on the performance of older drivers with a cognitive self-assessment bias

Scipedia content — Fri, 12 Feb 2021 16:10:04 +0100

Purpose: Depending on the calibration of their cognitive abilities, some older drivers (ODs) might stop driving prematurely (under-estimators, UEs) and others could expose themselves to risky situations (over-estimators, OEs). The aim of the study was to compare the effectiveness of two cognitive training (CT) programs intended for ODs presenting a cognitive calibration bias. We hypothesized that CT with feedback on performance can help ODs to correctly calibrate their abilities and consequently adapt their driving behavior.Method: One hundred and six ODs (≥70 years) were assigned to two CT groups (with or without a driving simulator experience, DS). These interventions lasted about 36 h and were distributed over a 3-month period. ODs completed objective and subjective cognitive evaluations and an on-road driving evaluation before and after training.Results: The first results on 67 participants (40 from the CT group, and 27 from the CT + DS group) showed an improvement of their visual processing speed, their divided attention and their selective attention after training. Participants from both groups also had an improved TRIP tactical sub-score (Test Ride for Investigating Practical fitness to drive), indicating a better driving behavioral adaptation. Finally, although both training programs seemed to be equally effective in correcting cognitive calibration bias, the results indicated that 21 UEs and 10 OEs were well calibrated and thus correctly self-assessed their cognitive abilities after training.Conclusion: Both CT programs (with or without DS experience) seem to improve the visual attention of ODs. UEs appeared to be more susceptible than OEs to this training and were better calibrated after it.

Document type: Article

Impact of Vehicular Countdown Signals on Driving Psychologies and Behaviors: Taking China as an Example

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

Countdown signal control is a relatively new control mode that can inform a driver in advance about the remaining time to pass through intersections or the time needed to wait for other drivers and pedestrians. At present, few countries apply vehicular countdown signals. However, in China, some cities have applied vehicular countdown signals for years, though it is unclear how and how much such signals influence driving psychologies and behaviors compared with non-countdown signal controls. The present work aims to clarify the impact of vehicular countdown signals on driving psychologies and behaviors on the cognitive level. A questionnaire survey with 32 questions about driving psychologies and behaviors was designed, and an online survey was conducted. A total of 1051 valid questionnaires were received. The survey data were analyzed, and the main results indicate that most of the surveyed drivers prefer countdown signal controls and think that such controls can improve not only traffic safety but also traffic operational efficiency. The surveyed drivers also think that countdown signal controls have an impact on driving psychologies and behaviors and the survey results have demonstrated that the driving behaviors of female drivers surveyed are not conservative under the clear conditions of green countdown signal control. Further studies and methods concerning the effects of countdown signals on driving psychologies and behaviors are discussed.

Document type: Article

General Principles of Integrity Checking of Digital Images and Application for Steganalysis

Scipedia content — Fri, 12 Feb 2021 16:05:31 +0100

"jats:p"The new common approach for integrity checking of digital images is developed. The new features of formal parameters defining image are revealed, theoretically grounded and practically tested. The characteristics of the mutual arrangement of left and right singular vectors corresponding to the largest singular value of the image’s matrix (block of matrix) and the vector composed of singular numbers is obtained. Formal parameters are obtained using normal singular decomposition of matrix (block of matrix) which is uniquely determined. It is shown that for most blocks of original image (no matter lossy or lossless) the angle between the left (right) mentioned singular vector and vector composed of singular numbers is defined by the angle between the n-optimal vector and the vector of standard basis of the range corresponding dimension. It is shown that the determined feature brakes for the mentioned formal parameters in a non-original image. This shows the integrity violation of the image, i.e. the existence of the additional information embedded using steganography algorithms. So this can be used as a basis for development of new universal steganography methods and algorithms, and one example of the realization is proposed. The efficiency of the proposed algorithm won’t depend on the details of steganography method used for embedding. All the obtained results can be easily adapted for the digital video and audio analysis.

Document type: Article

Dynamic Vehicle Scheduling for Working Service Network with Dual Demands

Scipedia content — Fri, 12 Feb 2021 16:05:15 +0100

This study aims to develop some models to aid in making decisions on the combined fleet size and vehicle assignment in working service network where the demands include two types (minimum demands and maximum demands), and vehicles themselves can act like a facility to provide services when they are stationary at one location. This type of problem is named as the dynamic working vehicle scheduling with dual demands (DWVS-DD) and formulated as a mixed integer programming (MIP). Instead of a large integer program, the problem is decomposed into small local problems that are guided by preset control parameters. The approach for preset control parameters is given. By introducing them into the MIP formulation, the model is reformulated as a piecewise form. Further, a piecewise method by updating preset control parameters is proposed for solving the reformulated model. Numerical experiments show that the proposed method produces better solution within reasonable computing time.

Document type: Article

Legal regulation of the international road transport of passengers

Scipedia content — Fri, 12 Feb 2021 16:00:19 +0100

Since March 2013 bus and coach passengers have a minimum set of rights when travelling in the European Union. Regulation 181/2011 concerning the rights of passengers in bus and coach transport applies to passengers traveling with regular services that operate at specified intervals along specified routes, with passengers being picked up and set down at predetermined stopping points. Either the boarding or the alighting point must be within the European Union. Some of the Regulation's provisions are mandatory and apply to all services. The other rights available under the Regulation only apply where the scheduled distance of the service is 250 km or more.

Document type: Article

Effectiveness of National Airlines in Europe – the DEA Approach

Scipedia content — Fri, 12 Feb 2021 15:00:31 +0100

"jats:p"National airlines operate in a highly competitive environment. EU airlines face a challenge to compete with low cost carriers, as a result of the liberalization process in the sector. European flag airlines of non-EU member states, not benefiting from liberalization, are forced to compete internationally. This research is focused on national carriers, as they provide the majority of service to and from central and regional airports. Therefore, to establish the most efficient entities on the passenger air transport market, DEA (Data Envelopment Analysis) methodology, has been utilized. The purpose of this paper is to evaluate the effectiveness of 29 chosen national airlines in Europe in the year 2013, using the DEA approach, to pinpoint the subset of fully-efficient market leaders, as well as potential sources of inefficiency, among less effective carriers. The analysis incorporates information on inputs (e.g. fleet, number of employees, number of countries and airports served) and outputs (revenue, annual passengers carried, load factor). The results show that more than 40% (12 of 29) researched airlines are effective and the other 34% are near-efficient. Moreover, outcomes suggest that “going big” may not increase effectiveness. It is harder to achieve full efficiency for big carriers than small ones.

Document type: Article

The Development of Reusable Luggage Tag with the Internet of Things for Mobile Tracking and Environmental Sustainability

Scipedia content — Fri, 12 Feb 2021 14:50:47 +0100

With more than two billion passengers worldwide travelling by air each year, vast amounts of lost luggage and disposable paper adhesive luggage tags are pushing the aviation industry to improve luggage tracking and reduce the one-off adhesive luggage paper tags. This paper reviews the current application of Radio Frequency Identification (RFID) in the luggage handling system and proposes the Internet of Things’ (IoT) development of the reusable luggage tag to facilitate aviation luggage handling, the tracking process and environmental conservation. A framework of IoT and its RFID components for the proposed reusable tag are presented. An integrated cyber-physical system, including a database management system and mobile app, for the reusable luggage tag is developed. Future studies will enhance the methodology of integrating the retail system, luggage tag, airport check-in counter, luggage handling system, aircraft, and the destination airport through the use of the tag, readers, antenna, and mobile devices.

Document type: Article

Analysis of an Automated Vehicle Routing Problem in Logistics considering Path Interruption

Scipedia content — Fri, 12 Feb 2021 14:43:53 +0100

The application of automated vehicles in logistics can efficiently reduce the cost of logistics and reduce the potential risks in the last mile. Considering the path restriction in the initial stage of the application of automated vehicles in logistics, the conventional model for a vehicle routing problem (VRP) is modified. Thus, the automated vehicle routing problem with time windows (AVRPTW) model considering path interruption is established. Additionally, an improved particle swarm optimisation (PSO) algorithm is designed to solve this problem. Finally, a case study is undertaken to test the validity of the model and the algorithm. Four automated vehicles are designated to execute all delivery tasks required by 25 stores. Capacities of all of the automated vehicles are almost fully utilised. It is of considerable significance for the promotion of automated vehicles in last-mile situations to develop such research into real problems arising in the initial period.

Document type: Article

Analysis and modelling of traffic produced by adaptive HTTP-based video

Scipedia content — Fri, 12 Feb 2021 14:38:09 +0100

The increase of HTTP-based video popularity causes that broadband and Internet service providers' links transmit mainly multimedia content. Network planning, traffic engineering or congestion control requires an understanding of the statistical properties of network traffic; therefore, it is desirable to investigate the characteristic of traffic traces generated by systems which employ adaptive bit-rate streaming. Our first contribution is an investigation of traffic originating from 120 client-server pairs, situated in an emulated content distribution network, and multiplexed onto a single network link. We show that the structure of the traffic is distinct from the structure generated by the first and second generation of HTTP video systems, and furthermore, not similar to the structure of general Internet traffic. The obtained traffic exhibits negative and positive correlations, anti-persistence, and its distribution function is skewed to the right. Our second contribution is an approximation of the traffic by ARIMA/FARIMA processes blue and artificial neural networks. As we show, the obtained traffic models are able to enhance the performance of an adaptive streaming algorithm.

Document type: Article

Distributed Energy Storage Control for Dynamic Load Impact Mitigation

Scipedia content — Fri, 12 Feb 2021 14:36:17 +0100

The future uptake of electric vehicles (EV) in low-voltage distribution networks can cause increased voltage violations and thermal overloading of network assets, especially in networks with limited headroom at times of high or peak demand. To address this problem, this paper proposes a distributed battery energy storage solution, controlled using an additive increase multiplicative decrease (AIMD) algorithm. The improved algorithm (AIMD+) uses local bus voltage measurements and a reference voltage threshold to determine the additive increase parameter and to control the charging, as well as discharging rate of the battery. The used voltage threshold is dependent on the network topology and is calculated using power flow analysis tools, with peak demand equally allocated amongst all loads. Simulations were performed on the IEEE LV European Test feeder and a number of real U.K. suburban power distribution network models, together with European demand data and a realistic electric vehicle charging model. The performance of the standard AIMD algorithm with a fixed voltage threshold and the proposed AIMD+ algorithm with the reference voltage profile are compared. Results show that, compared to the standard AIMD case, the proposed AIMD+ algorithm further improves the network’s voltage profiles, reduces thermal overload occurrences and ensures a more equal battery utilisation.

Document type: Article

Exploring the Influence of Attitudes to Walking and Cycling on Commute Mode Choice Using a Hybrid Choice Model

Scipedia content — Fri, 12 Feb 2021 14:34:31 +0100

Transport-related problems, such as automobile dependence, traffic congestion, and greenhouse emissions, lead to a great burden on the environment. In developing countries like China, in order to improve the air quality, promoting sustainable travel modes to reduce the automobile usage is gradually recognized as an emerging national concern. Though there are many studies related to the physically active modes (e.g., walking and cycling), the research on the influence of attitudes to active modes on travel behavior is limited, especially in China. To fill up this gap, this paper focuses on examining the impact of attitudes to walking and cycling on commute mode choice. Using the survey data collected in China cities, an integrated discrete choice model and the structural equation model are proposed. By applying the hybrid choice model, not only the role of the latent attitude played in travel mode choice, but also the indirect effects of social factors on travel mode choice are obtained. The comparison indicates that the hybrid choice model outperforms the traditional model. This study is expected to provide a better understanding for urban planners on the influential factors of green travel modes.

Document type: Article

The Effect of Connected Vehicle Environment on Global Travel Efficiency and Its Optimal Penetration Rate

Scipedia content — Fri, 12 Feb 2021 14:25:22 +0100

The effect of connected vehicle environment on the transportation systems and the relationship between the penetration rate of connected vehicle and its efficiency are investigated in this study. An example based on the classical two-route network is adopted in this study, in which the drivers consist of two types: informed and uninformed. The advantages and disadvantages of the connected vehicle environment are analyzed, and the concentration phenomenon is proposed and found to be mitigated when only a fraction of drivers are informed. The simulation tool embodying the characteristics of the connected vehicle environment is developed using the multiagent technology. Finally, different scenarios are simulated, such as the zero-information environment, the full-information environment, and the connected vehicle environment with various penetration rates. Moreover, simulation results of the global performance of the transportation system are compared. The results show that the connected vehicle environment can efficiently improve the performance of the transportation system, while the adverse effects due to concentration rise out from the excessive informed drivers. An optimal penetration rate of the connected vehicles is found to characterize the best performance of the system. These findings can aid in understanding the effect of the connected vehicle environment on the transportation system.

Document type: Article

A stock-flow cohort model of the national car fleet

Scipedia content — Fri, 12 Feb 2021 14:24:26 +0100

Purpose Various regulatory and fiscal policy instruments are in force to reduce the amount of greenhouse gases and local pollutants emitted by private cars. The incentives operate primarily—or exclusively—on the newest generation of cars. But how fast will technological developments affecting new vehicle models penetrate into the car fleet? The speed at which the adverse effects of private car use will be mitigated through the normal vehicle renewal process, or through an accelerated one, carries considerable interest. Suitable modelling tools are needed. This paper aims to demonstrate the usefulness and flexibility of a bottom-up stock-flow modelling approach to private car fleet forecasting and policy analysis. Methods In the BIG model of the Norwegian automobile fleet, the annual stocks and flows characterising the car fleet are specified as matrices of 682 mutually exclusive and exhaustive cells, formed by cross-tabulations between 22 vehicle segments and 31 age classes. New car registrations follow from a disaggregate generic discrete choice model based on two decades of complete sales data for individual passenger car models. Results Example projections are presented onto the 2050 horizon under a low carbon fiscal policy scenario as well as a business-as-usual scenario. The fiscal policy is seen to make a large difference in terms of long term fuel consumption and CO2 emissions. Conclusions Stock-flow cohort modelling of the automobile fleet is a powerful and handy tool for policy analysis. Even quite simple and straightforward accounting relations may provide important insights into the dynamics of fleet development. It is possible to incorporate, into the stock-flow modelling framework, interesting and useful behavioural relations, explaining aggregate automobile ownership and travel demand, scrapping and survival rates, or consumer choice in the market for new cars.

Document type: Article

A Regional Time-of-Use Electricity Price Based Optimal Charging Strategy for Electrical Vehicles

Scipedia content — Fri, 12 Feb 2021 14:23:56 +0100

With the popularization of electric vehicles (EVs), the out-of-order charging behaviors of large numbers of EVs will bring new challenges to the safe and economic operation of power systems. This paper studies an optimal charging strategy for EVs. For that a typical urban zone is divided into four regions, a regional time-of-use (RTOU) electricity price model is proposed to guide EVs when and where to charge considering spatial and temporal characteristics. In light of the elastic coefficient, the user response to the RTOU electricity price is analyzed, and also a bilayer optimization charging strategy including regional-layer and node-layer models is suggested to schedule the EVs. On the one hand, the regional layer model is designed to coordinate the EVs located in different time and space. On the other hand, the node layer model is built to schedule the EVs to charge in certain nodes. According to the simulations of an IEEE 33-bus distribution network, the performance of the proposed optimal charging strategy is verified. The results demonstrate that the proposed bilayer optimization strategy can effectively decrease the charging cost of users, mitigate the peak-valley load difference and the network loss. Besides, the RTOU electricity price shows better performance than the time-of-use (TOU) electricity price.

Document type: Article

Concepts and new perspectives for long span bridges

Scipedia content — Fri, 12 Feb 2021 14:21:30 +0100

A discussion of the dominant factors affecting the behaviour of long span cable supported bridges is the subject of this paper. The main issue is the evolution of properties and response of the bridge with the size of the structure, represented by the critical parameter of span length, showing how this affects the conceptual design. After a review of the present state of the art, perspectives for future developments are discussed.

Document type: Article

NEAT: a framework for building fully automated NGS pipelines and analyses

Scipedia content — Fri, 12 Feb 2021 14:18:11 +0100

Background: The analysis of next generation sequencing (NGS) has become a standard task for many laboratories in the life sciences. Though there exists several tools to support users in the manipulation of such datasets on various levels, few are built on the basis of vertical integration. Here, we present the NExt generation Analysis Toolbox (NEAT) that allows non-expert users including wet-lab scientists to comprehensively build, run and analyze NGS data through double-clickable executables without the need of any programming experience. Results: In comparison to many publicly available tools including Galaxy, NEAT provides three main advantages: (1) Through the development of double-clickable executables, NEAT is efficient (completes within "24 hours), easy to implement and intuitive; (2) Storage space, maximum number of job submissions, wall time and cluster-specific parameters can be customized as NEAT is run on the institution’s cluster; (3) NEAT allows users to visualize and summarize NGS data rapidly and efficiently using various built-in exploratory data analysis tools including metagenomic and differentially expressed gene analysis. To simplify the control of the workflow, NEAT projects are built around a unique and centralized file containing sample names, replicates, conditions, antibodies, alignment-, filtering- and peak calling parameters as well as cluster-specific paths and settings. Moreover, the small-sized files produced by NEAT allow users to easily manipulate, consolidate and share datasets from different users and institutions. Conclusions: NEAT provides biologists and bioinformaticians with a robust, efficient and comprehensive tool for the analysis of massive NGS datasets. Frameworks such as NEAT not only allow novice users to overcome the increasing number of technical hurdles due to the complexity of manipulating large datasets, but provide more advance users with tools that ensure high reproducibility standards in the NGS era. NEAT is publically available at https://github.com/pschorderet/NEAT. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-0902-3) contains supplementary material, which is available to authorized users.

Document type: Article

The Influence of The Static Layout on The Stress and Deformation State for Concrete Arched Bridges with Upper Carriageway

Scipedia content — Fri, 12 Feb 2021 14:16:25 +0100

Arch bridges were the first constructions with considerable spans built by man, due to the materials and technologies available at that time. Afterwards, these works of art have diversified and are now solutions used in countless situations, especially when crossing deep valleys."/jats:p""jats:p"Both their economic and architectonic aspects are hard to combat and have led to selecting this type of structure for more and more locations."/jats:p""jats:p"The paper will contain a brief presentation of some aspects regarding upper path concrete arch bridges composition and design methods. Also, it will have a case study regarding structural stresses over the different construction stages, and for several support hypotheses."/jats:p""jats:p"The case study will reflect the Crivadia viaduct, situated on DN 66, at km 150+672. The bridge has a main span of 59.20m and an overall height of 15.00m, serving a 7.80m wide carriageway and two 2.20m wide footways. It has a total length of 107.60m. "/jats:p""jats:p"Based on the results of the case study, conclusions will be drawn regarding stress variation over the construction stages and under different support hypothesis, comparing these with the initial results.

Document type: Article

Rare-earth-free propulsion motors for electric vehicles: a technology review

Scipedia content — Fri, 12 Feb 2021 14:15:23 +0100

Several factors including fossil fuels scarcity, prices volatility, greenhouse gas emissions or current pollution levels in metropolitan areas are forcing the development of greener transportation systems based on more efficient electric and hybrid vehicles. Most of the current hybrid electric vehicles use electric motors containing powerful rare-earth permanent magnets. However, both private companies and estates are aware of possible future shortages, price uncertainty and geographical concentration of some critical rare-earth elements needed to manufacture such magnets. Therefore, there is a growing interest in developing electric motors for vehicular propulsion systems without rare-earth permanent magnets. In this paper this problematic is addressed and the state-of-the-art of the electric motor technologies for vehicular propulsion systems is reviewed, where the features required, design considerations and restrictions are addressed.

Peer Reviewed

Document type: Article

Priority-Aware Packet Pre-marking for DiffServ Architecture Based on H.264/SVC Video Stream Structure

Scipedia content — Fri, 12 Feb 2021 14:09:09 +0100

The H264/SVC codec allows for generation of hierarchical video streams. In the stream of this type video data belonging to different layers have different priority depending on their importance to the quality of the video and the decoding process. This creates new demands on the mechanisms of packet marking, and thus new challenges for the policy guaranteeing QoS parameters, such as those defined in the DiffServ architecture. Therefore, mechanisms of the traffic engineering used in the DiffServ network should, as far as possible, take into account internal distribution of priorities inside video streams. This may be achieved by implementing an appropriate method for packet pre-marking. The paper describes the Weighted Priority Pre-marking (WPP) algorithm for priority-aware SVC video streaming over a DiffServ network. Our solution takes into account the relative importance of the Network Abstraction Layer Units. It also does not require any changes in the implementation of the DiffServ marker algorithm. The results presented confirm that video transmission in the DiffServ domain, based on the WPP packet pre-marking, can provide better perceived video quality than the standard (best effort) streaming of multi-layered SVC video. In addition, a comparison with the transmission of the same video content encoded with the H264/AVC codec also points to the superiority of our proposed method.

Document type: Article

The Impact of Perception toward the Built Environment in Airport Access Mode Choice Using Hybrid Choice Modeling

Scipedia content — Fri, 12 Feb 2021 14:06:17 +0100

Built environment (BE), as an objective variable, plays a substantial role in urban residents’ behavior. However, the perception toward a BE, as a subjective variable, varies among people. To identify the role of perception toward BE, we used a stated preference (SP) survey conducted in January–February 2015 at the Imam Khomeini International Airport (IKIA), Tehran, Iran. The data was drawn from 641 individuals; 359 of them were residents of Tehran. For the estimation of the model, a hybrid discrete choice model was used to capture the latent variable, in addition to mode attributes and trip conditions, with 1795 SP observations. Psychometric questions concerned the perception of ease in access to main streets or highways and good traffic conditions within their residential areas. The results showed that the latent variable (positive perception toward built environment or PBE) had a significant positive effect on people’s willingness to park at the airport. Moreover, the gender, age, marital status, level of education, experience living in a foreign country, and income level also influenced the formation of perception toward the BE and airport transportation mode choice.

Document type: Article

Shortest-Way: An Improved Empirical Transition Method for Signal Coordination

Scipedia content — Fri, 12 Feb 2021 14:03:22 +0100

Four fundamental insights into transition methods are provided from the perspective of traffic engineers. An improved empirical transition method (i.e., Shortest-way) is developed with the goal of reducing the time spent on offset correction and the offset deviations of the coordinated phases during the transition period. Shortest-way operates stepwise and can be activated to correct offset at the scheduled time to switch plans. The maximum amount of adjustment that can be made to a transition cycle length is calculated based on the timing parameters of active phases in the old and new plans. The problem of cycle length distribution is formulated as a nonlinear integer programming problem, aiming at minimizing the sum of the squares of the intersection offset deviations of all the transition cycles. The portion of the cycle length that can be allocated to each phase in a transition cycle is calculated based on its splits in the old and new plans and its potential contribution to the maximum amount of adjustment to the cycle length. The numerical experimental results proved the potential advantage of Shortest-way over CORSIM Shortway and justified the necessity for managing the time to switch plans at the intersection level.

Document type: Article

Pose Self-Calibration of Stereo Vision Systems for Autonomous Vehicle Applications

Scipedia content — Fri, 12 Feb 2021 14:02:25 +0100

Nowadays, intelligent systems applied to vehicles have grown very rapidly; their goal is not only the improvement of safety, but also making autonomous driving possible. Many of these intelligent systems are based on making use of computer vision in order to know the environment and act accordingly. It is of great importance to be able to estimate the pose of the vision system because the measurement matching between the perception system (pixels) and the vehicle environment (meters) depends on the relative position between the perception system and the environment. A new method of camera pose estimation for stereo systems is presented in this paper, whose main contribution regarding the state of the art on the subject is the estimation of the pitch angle without being affected by the roll angle. The validation of the self-calibration method is accomplished by comparing it with relevant methods of camera pose estimation, where a synthetic sequence is used in order to measure the continuous error with a ground truth. This validation is enriched by the experimental results of the method in real traffic environments. This work was supported by the Spanish Government through the CICYTprojects (TRA2013-48314-C3-1-R and TRA2015-63708-R) and Comunidad de Madrid through SEGVAUTO-TRIES (S2013/MIT-2713). Publicado

Document type: Article

Development of Accident Frequency Models with Random Parameters on Interstate Roadway Segments with and without Lighting Systems

Scipedia content — Fri, 12 Feb 2021 14:02:03 +0100

This study explored factors affecting traffic accidents in roadway segments with and without lighting systems using a random parameter negative binomial model. This study sought to make up for a shortcoming of the fixed parameter model that constrained the estimated parameters to be fixed across observations, by applying random parameters that can take into account unobserved heterogeneity. Three variables had a random parameter among nine significant variables in segments with lighting systems, while seven of the eleven significant variables in a segment without a lighting system had random parameters. The different influence of interstate highway geometrics on vehicle crashes with and without lighting systems found through this study considering unobserved heterogeneity may hopefully help reduce accident frequencies and consider installation of lighting systems on interstate highways in the future.

Document type: Article

Automated Incident Detection Using Real-Time Floating Car Data

Scipedia content — Fri, 12 Feb 2021 13:51:57 +0100

The aim of this paper is to demonstrate the feasibility of a live Automated Incident Detection (AID) system using only Floating Car Data (FCD) in one of the first large-scale FCD AID field trials. AID systems detect traffic events and alert upcoming drivers to improve traffic safety without human monitoring. These automated systems traditionally rely on traffic monitoring sensors embedded in the road. FCD allows for finer spatial granularity of traffic monitoring. However, low penetration rates of FCD probe vehicles and the data latency have historically hindered FCD AID deployment. We use a live country-wide FCD system monitoring an estimated 5.93% of all vehicles. An FCD AID system is presented and compared to the installed AID system (using loop sensor data) on 2 different highways in Netherlands. Our results show the FCD AID can adequately monitor changing traffic conditions and follow the AID benchmark. The presented FCD AID is integrated with the road operator systems as part of an innovation project, making this, to the best of our knowledge, the first full chain technical feasibility trial of an FCD-only AID system. Additionally, FCD allows for AID on roads without installed sensors, allowing road safety improvements at low cost.

Document type: Article

On the Front Lines of a Sustainable Transportation Fleet: Applications of Vehicle-to-Grid Technology for Transit and School Buses

Scipedia content — Fri, 12 Feb 2021 13:37:49 +0100

The electricity generation/supply and transportation sectors are the two largest contributors to greenhouse gas (GHG) emissions in the U.S., and vehicle-to-grid (V2G) technology is a rapidly emerging solution to reduce these emissions with the adoption of battery-electric (BE) vehicles. Deployments of BE transit and school buses are expected to have larger battery capacities than passenger vehicles, making them more feasible candidates for V2G service. Five electricity generation regions are considered for cash flow analysis of BE and diesel transit and school buses over their entire respective lifetimes with the allowance of V2G services’ net revenue. Besides, the environmental benefits of using the V2G system are studied in place of combustion power generation plants for the regulation services of each study region. Air emission externalities are another crucial issue for bus operations because buses are operated near highly populated areas, so these externalities are also studied in this research with the benefits of a V2G emission reduction potential taken into account. The analysis concluded that BE transit and school buses with V2G application have potential to reduce electricity generation related greenhouse-gas emissions by 1067 and 1420 tons of CO2 equivalence (average), and eliminate $13,000 and $18,300 air pollution externalities (average), respectively.

Document type: Article

Robust peak-shaving for a neighborhood with electric vehicles

Scipedia content — Fri, 12 Feb 2021 13:37:28 +0100

Demand Side Management (DSM) is a popular approach for grid-aware peak-shaving. The most commonly used DSM methods either have no look ahead feature and risk deploying flexibility too early, or they plan ahead using predictions, which are in general not very reliable. To counter this, a DSM approach is presented that does not rely on detailed power predictions, but only uses a few easy to predict characteristics. By using these characteristics alone, near optimal results can be achieved for electric vehicle (EV) charging, and a bound on the maximal relative deviation is given. This result is extended to an algorithm that controls a group of EVs such that a transformer peak is avoided, while simultaneously keeping the individual house profiles as flat as possible to avoid cable overloading and for improved power quality. This approach is evaluated using different data sets to compare the results with the state-of-the-art research. The evaluation shows that the presented approach is capable of peak-shaving at the transformer level, while keeping the voltages well within legal bounds, keeping the cable load low and obtaining low losses. Further advantages of the methodology are a low communication overhead, low computational requirements and ease of implementation.

Document type: Article

Reallocating charging loads of electric vehicles in distribution networks

Scipedia content — Fri, 12 Feb 2021 13:36:13 +0100

In this paper, the charging loads of electric vehicles were controlled to avoid their impact on distribution networks. A centralized control algorithm was developed using unbalanced optimal power flow calculations with a time resolution of one minute. The charging loads were optimally reallocated using a central controller based on non-linear programming. Electric vehicles were recharged using the proposed control algorithm considering the network constraints of voltage magnitudes, voltage unbalances, and limitations of the network components (transformers and cables). Simulation results showed that network components at the medium voltage level can tolerate high uptakes of uncontrolled recharged electric vehicles. However, at the low voltage level, network components exceeded their limits with these high uptakes of uncontrolled charging loads. Using the proposed centralized control algorithm, these high uptakes of electric vehicles were accommodated in the network under study without the need of upgrading the network components.

Document type: Article

An Empirical Framework for Intersection Optimization Based on Uniform Design

Scipedia content — Fri, 12 Feb 2021 13:33:41 +0100

Operational performance optimization of signalized intersections is one of the most important tasks for traffic engineers and researchers. To compensate for the limitations of practical implementation, simulation software packages have been widely used to evaluate different optimization strategies and thus to improve the efficiency of the intersections as well as the entire network. However, for the existing optimization studies on signalized intersections, the relationships among various optimization measures and the combination of strategies have not been fully investigated. In this paper, uniform design experimentation was introduced to combine different optimization measures into strategies and achieve the minimum time cost in model construction. VISSIM software package was then calibrated and used to evaluate various optimization strategies and identify the one with the best measurement of performance, namely, control delay at the signalized intersection. By taking a representative congested intersection in Shanghai as a case study, the optimal strategy was identified to reduce the overall control delay by 27.3%, which further verified the modeling capability of the proposed method.

Document type: Article

A Preliminary Assessment of the Initial Compression Power Requirement in CO2 Pipeline “Carbon Capture and Storage (CCS) Technologies”

Scipedia content — Fri, 12 Feb 2021 13:25:23 +0100

CO2 captured from fossil-fueled power generation plants is said to be economically transported via pipelines over long distances. The CO2 must be compressed to pipeline specifications using compressors and pumps that are driven by gas turbine (GT) or other prime movers. This paper presents the evaluation of actual work transfer or required prime power by modeling the governing equations of compression using the Peng–Robinson equation of state (PR-EOS). A computer code was developed to carry out the modeling and subsequent simulation of the compression power requirement. The simulation of prime mover power was carried out for different technology (head per stage) of the compressor ranging from 10-staged compression to double stage compression. The results show that the current technology of the centrifugal compressor could require as much as 23MW of prime mover power to compress 1.5 million tonnes per year of CO2—a projected equivalent CO2 released from a 530MW combined cycle gas turbine (CCGT) power generation plant.

Document type: Article

Radiation fog formation alerts using attenuated backscatter power from automatic lidars and ceilometers

Scipedia content — Fri, 12 Feb 2021 13:15:42 +0100

Abstract. Radiation fog occurs over many locations around the world in stable atmospheric conditions. Air traffic at busy airports can be significantly disrupted because low visibility at the ground makes it unsafe to take off, land and taxi on the ground. Current numerical weather prediction forecasts are able to predict general conditions favorable for fog formation, but not the exact time or location of fog occurrence. A selected set of observations available in near-real time at strategic locations could also be useful to track the evolution of key processes and key parameters that drive fog formation. Such observations could complement the information predicted by numerical weather prediction (NWP) models that is made available to airport forecasters in support of their fog forecast. This paper presents an experimental setup based on collocated automatic lidar and ceilometer measurements, relative humidity measurements and horizontal visibility measurements to study hygroscopic growth of fog condensation nuclei. This process can take several minutes to hours, and can be tracked using lidar- or ceilometer-attenuated backscatter profiles. Based on hygroscopic growth laws we derive a set of parameters that can be used to provide alerts minutes to hours prior to formation of radiation fog. We present an algorithm that uses the temporal evolution of attenuated backscatter measurements to derive pre-fog formation alerts. The performance of the algorithm is tested on 45 independent pre-fog situations at two locations (near Paris, France, and Brussels, Belgium). We find that an alert for pre-fog conditions predominantly occurs 10–50 min prior to fog formation at an altitude ranging 0 to 100 m above ground. In a few cases, alerts can occur up to 100 min prior to fog formation. Alert durations are found to be sensitive to the relative humidity conditions found a few hours prior to the fog.

Document type: Article

Road Surface State Recognition Based on SVM Optimization and Image Segmentation Processing

Scipedia content — Fri, 12 Feb 2021 13:10:31 +0100

Adverse road condition is the main cause of traffic accidents. Road surface condition recognition based on video image has become a central issue. However, hybrid road surface and road surface under different lighting environments are two crucial problems. In this paper, the road surface states are categorized into 5 types including dry, wet, snow, ice, and water. Then, according to the original image size, images are segmented; 9-dimensional color eigenvectors and 4 texture eigenvectors are extracted to construct road surface state characteristics database. Next, a recognition method of road surface state based on SVM (Support Vector Machine) is proposed. In order to improve the recognition accuracy and the universality, a grid searching algorithm and PSO (Particle Swarm Optimization) algorithm are used to optimize the kernel function factor and penalty factor of SVM. Finally, a large number of actual road surface images in different environments are tested. The results show that the method based on SVM and image segmentation is feasible. The accuracy of PSO algorithm is more than 90%, which effectively solves the problem of road surface state recognition under the condition of hybrid or different video scenes.

Document type: Article

A Novel Space-Time-Speed Method for Increasing the Passing Capacity with Safety Guaranteed of Railway Station

Scipedia content — Fri, 12 Feb 2021 13:09:22 +0100

A method for improving the passing capacity of a station without adding any track and equipment is proposed in this paper. In the process of handling train routes, by transforming the existing fixed train-approaching locking section into a variable mode, the route locking time is shortened and in-station resource consumption is reduced. This approach improves the capacity of the station. At the same time, delay of the train can be quickly returned to normal. A method of variable train-approaching locking section is discussed; a mathematical model for increasing station passing capacity is shown. Comparison between the impact of a variable train-approaching locking section and a fixed mode on the station passing capacity is shown.

Document type: Article

Comparison of the Short-Term Forecasting Accuracy on Battery Electric Vehicle between Modified Bass and Lotka-Volterra Model: A Case Study of China

Scipedia content — Fri, 12 Feb 2021 13:08:48 +0100

The potential demand of battery electric vehicle (BEV) is the base of the decision-making to the government policy formulation, enterprise manufacture capacity expansion, and charging infrastructure construction. How to predict the future amount of BEV accurately is very important to the development of BEV both in practice and in theory. The present paper tries to compare the short-term accuracy of a proposed modified Bass model and Lotka-Volterra (LV) model, by taking China’s BEV development as the case study. Using the statistics data of China’s BEV amount of 21 months from Jan 2015 to Sep 2016, we compare the simulation accuracy based on the value of mean absolute percentage error (MAPE) and discuss the forecasting capacity of the two models according to China’s government expectation. According to the MAPE value, the two models have good prediction accuracy, but the Bass model is more accurate than LV model. Bass model has only one dimension and focuses on the diffusion trend, while LV model has two dimensions and mainly describes the relationship and competing process between the two populations. In future research, the forecasting advantages of Bass model and LV model should be combined to get more accurate predicting effect.

Document type: Article

Characteristic Analysis of Mixed Traffic Flow of Regular and Autonomous Vehicles Using Cellular Automata

Scipedia content — Fri, 12 Feb 2021 13:08:30 +0100

The technology of autonomous vehicles is expected to revolutionize the operation of road transport systems. The penetration rate of autonomous vehicles will be low at the early stage of their deployment. It is a challenge to explore the effects of autonomous vehicles and their penetration on heterogeneous traffic flow dynamics. This paper aims to investigate this issue. An improved cellular automaton was employed as the modeling platform for our study. In particular, two sets of rules for lane changing were designed to address mild and aggressive lane changing behavior. With extensive simulation studies, we obtained some promising results. First, the introduction of autonomous vehicles to road traffic could considerably improve traffic flow, particularly the road capacity and free-flow speed. And the level of improvement increases with the penetration rate. Second, the lane-changing frequency between neighboring lanes evolves with traffic density along a fundamental-diagram-like curve. Third, the impacts of autonomous vehicles on the collective traffic flow characteristics are mainly related to their smart maneuvers in lane changing and car following, and it seems that the car-following impact is more pronounced.

Document type: Article

Agent-Based Modelling and Simulation to Assess the Impact of Parking Reservation System

Scipedia content — Fri, 12 Feb 2021 13:06:41 +0100

With the increasing popularity of smart phones, Parking Reservation System (PRS) becomes practical to reduce the travel time in cruising for vacant spaces. The aim of this study is to assess the impact of PRS explicitly. This paper was started with analyzing the processes of cruising for vacant spaces and making parking reservation decisions. The vehicles were divided into two categories: the intelligent vehicles and the regular ones. Only the intelligent vehicles have the ability to make a parking reservation beforehand, while the regular ones have to cruise for vacant spaces. All involved components were treated as different agents, including vehicles, parking lots, network, and management center. Based on this, agent-based simulation was introduced to evaluate the performances of the scenarios with different penetration rates. The simulation results indicate the average travel time increases with the improvement of the penetration rates for the regular vehicles. The assessment method presented in this study would assist in promoting the performances of PRS in urban areas.

Document type: Article

Time-Varying Hydraulic Gradient Model of Paste-Like Tailings in Long-Distance Pipeline Transportation

Scipedia content — Fri, 12 Feb 2021 13:02:33 +0100

Paste-like tailings slurry (PTLS) is always simplified as a Bingham plastic fluid, leading to excessive computational errors in the calculation of the hydraulic gradient. In the case of paste-like tailings in long-distance pipeline transportation, to explore a high-precision and reliable hydraulic gradient formula, the rheological behavior of paste-like tailings slurry was analyzed, a time-varying hydraulic gradient model was constructed, and a series of laboratory shear tests were conducted. The results indicate that the PTLS shows noticeable shear-thinning characteristics in constant shear tests; the calculated hydraulic gradient declined by about 56%, from 4.44 MPa·km"jats:sup"−1"/jats:sup" to 1.95 MPa·km"jats:sup"−1"/jats:sup" within 253 s, and remained constant for the next four hours during the pipeline transportation. Comparing with the balance hydraulic gradient obtained in a semi-industrial loop test, the computational errors of those calculated by using the time-varying hydraulic gradient model, Jinchuan formula, and Shanxi formula are 15%, 78%, and 130%, respectively. Therefore, our model is a feasible and high-precision solution for the calculation of the hydraulic gradient of paste-like tailings in long-distance pipeline transportation.

Document type: Article

A Framework for Estimating Long Term Driver Behavior

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

The authors present a cyber-physical systems study on the estimation of driver behavior in autonomous vehicles and vehicle safety systems. Extending upon previous work, the approach described is suitable for the long term estimation and tracking of autonomous vehicle behavior. The proposed system makes use of a previously defined Hybrid State System and Hidden Markov Model (HSS+HMM) system which has provided good results for driver behavior estimation. The HSS+HMM system utilizes the hybrid characteristics of decision-behavior coupling of many systems such as the driver and the vehicle, uses Kalman Filter estimates of observable parameters to track the instantaneous continuous state, and estimates the most likely driver state. The HSS+HMM system is encompassed in a HSS structure and inter-system connectivity is determined by using Signal Processing and Pattern Recognition techniques. The proposed method is suitable for scenarios that involve unknown decisions of other individuals, such as lane changes or intersection precedence/access. The long term driver behavior estimation system involves an extended HSS+HMM structure that is capable of including external information in the estimation process. Through the grafting and pruning of metastates, the HSS+HMM system can be dynamically updated to best represent driver choices given external information. Three application examples are also provided to elucidate the theoretical system.

Comment: 10 page

Document type: Article

Use of Information Intelligent Components for the Analysis of Complex Processes of Marine Energy Systems

Scipedia content — Fri, 12 Feb 2021 12:44:03 +0100

"jats:p" Synchronous motors and their modifications (ac converter-fed motor, etc.) enable to develop low-noise, reliable and economically efficient electric drive systems. The construction of up-to-date systems based on the synchronous machines is impossible without development of the computing software incorporating mathematical and computing simulation. In its turn, modelling of the synchronous machines as a rule is based on the equations by Park-Gorev, application of which requires adoption of a series of allowances. These allowances in a number of cases do not permit to obtain adequate results of the simulation coinciding with the results of field experiments of the systems under review. Moreover, while applying the system of equations by Park-Gorev to research the systems including interaction of synchronous machines with semiconducting converters of electric energy it is necessary simulate the process of formation their controlling signals in the sphere of frequency. If the states of converter’s keys are defined not only by controlling impulses but also by the state of currents in the synchronous machines flowing through them, such approach is not reasonable.

Document type: Article

Aircraft Automatic Control System Failure and Flight Safety

Scipedia content — Fri, 12 Feb 2021 12:41:27 +0100

"jats:p" This article presents a mathematical model estimating the probability of successful completion of the aircraft’s flight in case of aviation equipment failure in flight. This paper shows the relationship between the aircraft’s automatic control system and flight safety. The calculations of probability are made for the successful completion of the flight on Boeing 737 aircraft when the automatic control system has failed.

Document type: Article

Analysis of an Unmanned Aerial Vehicle Monitoring System for Resurveying of Shipping Routes

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

ksandrs Urbahs  / Rima Mickevičienė / Vasilij Djačkov / Kristīne Carjova / Valdas Jankūnas / Mindaugas Zakarauskas / Natalia Panova / Dita Lasmane Published Online: 2017-03-14 | DOI: https://doi.org/10.1515/tae-2016-0012 Abstract The paper gives brief description of the conventional and innovative hydrography survey methods and constraints connected with the realization. Proposed hydrographic survey system based on the use of Unmanned Aerial and Maritime systems provides functionality to conduct hydrographic measurements and environment monitoring. System can be easily adapted to fulfil marine safety and security operations, e.g. intrusion threat monitoring, hazardous pollutions monitoring and prevention operations, icing conditions monitoring.

Document type: Article

Migración y transnacionalismo: Experiencias de inmigrantes en el transporte público de San Diego, California, 2004

Scipedia content — Fri, 12 Feb 2021 12:39:10 +0100

Con la idea de que las prácticas cotidianas entre los inmigrantes mexicanos permiten construir y redefinir el espacio transnacional, como punto de partida, en este artículo se explorará la noción de la migración desde la perspectiva del transnacionalismo, en el marco de las tendencias contemporáneas del fenómeno migratorio en México. Al examinar las interacciones de los inmigrantes en el transporte público en San Diego, California, se buscará entender cómo se crean y recrean sus acciones. Este acercamiento desde un espacio social, permite analizar las interacciones específicas entre sociedades con historias y procesos de desarrollo diferentes. Based on the idea that everyday practices among Mexican immigrants allow the construction and redefinition of a transnational space, as a starting point, this article will explore the notion of migration from the perspective of transnationalism, within the framework of current tendencies in Mexican migration. Examining immigrant interactions in the public transportation system in San Diego, California, we will try to understand how they create and recreate their actions. This approach from a social space allows the analysis of the specific interactions between societies with different histories and development processe

Document type: Article

Role of Railway Transport in Tourism: Selected Problems and Examples in Slovakia

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

Transport is a very important part of activities in the tourism sector. In addition to the transport of tourists to and within a destination, transport itself can be a tourist attraction. The aim of this paper is to analyse selected problems of railways in Slovakia (a decrease in the importance of railways for passenger transport in Slovakia in the past 20 years, discontinued passenger transport on certain railway tracks and the modernisation of other tracks, and zero-fare public rail transport services for certain categories of passengers), and to present good examples of the use of narrow-gauge railways for the purposes of tourism (the Tatra Electric Railways and the Kysuce-Orava Forest Railway).

Document type: Article

Doppler Effect-Based Automatic Landing Procedure for UAV in Difficult Access Environments

Scipedia content — Fri, 12 Feb 2021 12:35:44 +0100

Currently, almost unrestricted access to low-lying areas of airspace creates an opportunity to use unmanned aerial vehicles (UAVs), especially those capable of vertical take-off and landing (VTOL), in transport services. UAVs become increasingly popular for transporting postal items over small, medium, and large distances. It is forecasted that, in the near future, VTOL UAVs with a high take-off weight will also deliver goods to very distant and hard-to-reach locations. Therefore, UAV navigation plays a very important role in the process of carrying out transport services. At present, during the flight phase, drones make use of the integrated global navigation satellite system (GNSS) and the inertial navigation system (INS). However, the inaccuracy of GNSS + INS makes it unsuitable for landing and take-off, necessitating the guidance of a human UAV operator during those phases. Available navigation systems do not provide sufficiently high positioning accuracy for an UAV. For this reason, full automation of the landing approach is not possible. This paper puts forward a proposal to solve this problem. The authors show the structure of an autonomous system and a Doppler-based navigation procedure that allows for automatic landing approaches. An accuracy evaluation of the developed solution for VTOL is made on the basis of simulation studies.

Document type: Article

Oil pollution in the southeastern Baltic Sea by satellite remote sensing data in 2004-2015

Scipedia content — Fri, 12 Feb 2021 12:29:45 +0100

"jats:p"The results of satellite monitoring of oil pollution in the Southeastern Baltic Sea in 2004-2015 are discussed in the paper. Interannual and seasonal variability of oil pollution is investigated. A steady decrease in total oil pollution was observed from 2004 to 2011. After a sharp increase of oil pollution in 2012, oil pollution level has established at 0.39 PI Index. Maximum of oil spills is observed in the spring and summer, which is probably due to favorable weather conditions for the detection of oil spills on radar images. According to the analysis of the shapes of the detected oil spills, it was concluded that the main polluters of the sea surface are vessels. No oil spills originated from the oil platform D-6 was detected in 2004-2015. Results of numerical experiments with the Seatrack Web oil spill model show that in the case of potential discharge of oil from the D-6 platform, oil will not reach the Curonian Spit beaches during 48 h after an accident.

Document type: Article

Analysis of Autonomous Vehicle Policies

Scipedia content — Thu, 11 Feb 2021 17:56:30 +0100

The rapid development and adoption of connected and autonomous vehicles will transform the U.S. transportation system over the next 30 years. Although the widespread use of fully connected and autonomous vehicles is still several years away, it is nonetheless critical that legislators, policymakers, and regulators understand how the presence of these vehicles will restructure the operation of roadway networks. Without a doubt, lawmakers and policymakers will need to develop new laws — and revise existing ones — to account for the presence of connected and autonomous vehicles. This report provides an overview of connected and autonomous vehicles — their positives and negatives, how quickly consumers may adopt them, and strategies state departments of transportation can use to streamline their deployment — before examining the recent efforts at the federal and state level to establish laws and regulations that will smooth the transition for connected and autonomous vehicles. Federal agencies, such as the National Highway Traffic Safety Administration, have issued guidance for manufacturers and state and local governments. Meanwhile, numerous states have enacted or proposed legislation to deal with connected and autonomous vehicles. The content of these statutes varies among states, however, shared areas of concern include defining what constitutes an autonomous vehicle, establishing basic protocols for testing autonomous vehicles on public roadways, specifying under what circumstances a manufacturer is liable for crashes, and setting guidelines for operating autonomous vehicles. Looking toward the Commonwealth, a review of the Kentucky Revised Statutes and Kentucky Administrative Regulations identifies current policies and regulations that may apply to connected and autonomous vehicles. Policymakers and legislators will likely have to grapple with issues pertaining to licensing, registration, cell phone usage, and the definition of vehicle operators in the context of autonomous vehicles. Given that the proliferation of connected and autonomous vehicles will accelerate over the next 10-15 years, Kentucky will benefit if these issues are addressed and resolved in a timely manner.

Casestudy Appelscha: Een onderzoek naar de implementatie van automatisch vervoer in het buitengebied

Scipedia content — Thu, 11 Feb 2021 17:52:07 +0100

Dit rapport is een uitwerking van de casestudy Appelscha welke is uitgevoerd in het kader van werkpakket 7 van het STAD project. Het STAD project bestudeert het effect van zelfrijdende voertuigen op vervoers- en locatiekeuzes van personen en bedrijven en op het ruimtelijk ontwerp van steden en wegen. Werkpakket 7 focust binnen het project op de huidige pilots en wat daarvan geleerd kan worden. Een van de pilots welke onder de loep is genomen, is het project met automatisch vervoer welke heeft plaatsgevonden in Appelscha. Het dorp Appelscha maakt deel uit van de gemeente Ooststellingwerf (Friesland) en wordt geconfronteerd met een voorspelde daling van het aantal inwoners en een reeds krimpend openbaar vervoersnetwerk. Om de toegankelijkheid van de regio te behouden, startte de gemeente Ooststellingwerf een pilot met elektrische geautomatiseerde voertuigen. Het is van toenemend belang om te leren van de ervaringen van reeds uitgevoerde projecten. De ervaringen van Appelscha worden in deze casestudy vastgelegd en gedeeld. In deze rapportage kunt u lezen hoe het opzetten en het uitvoeren van de pilot is verlopen.

ACTIVAGE - Interoperability layer architecture

Scipedia content — Thu, 11 Feb 2021 14:29:58 +0100

This document is the deliverable D3.2.2 or D3.7 "ACTIVAGE Interoperability layer architecture" and represent the main outcome of the activity T3.1 "Specification of the open cross-pilot ACTIVAGE architecture", that is part of Work Package WP3 "ACTIVATE Secure Interoperability Layer". The present document is also tightly related to other WP3 task: T3.4 "Implementation of the interoperability layer" that integrates T3.2 "ACTIVAGE solution for security and privacy" and T3.3 "Building bridges to the IoT protocols and platforms". The overall scope of this deliverable is to present the ACTIVATE Interoperability layer architecture. The content of this deliverable can be summarized as follows: Section 1 describes the nature and the reason why this deliverable 3.2.2 has particular relevance for the ACTIVAGE project. Moreover, this section also set the objectives to the defined structure and organisation of the document, and notes the differences between the 2 versions of the deliverable (D3.2 and D3.2.2). Section 2 is an introductory section that provides a brief description about main concepts from the Internet of Things that are involved in the ACTIVAGE project. This section also addresses the potential of Internet of Things in the context of the Active and Healthy Ageing area that concerns the ACTIVAGE project. In this section, the objectives and proposals of the deliverable are explained in detail besides the challenges that must be confronted to reach the deliverable goals. Section 3 of the present document is dedicated to the IoT Platform Interoperability State of the Art. This section is fruit of an extensive research and organisational collective work, as it is described in the section below. Here the main objectives to pursue, such as the achievement of interoperability within IoT platforms, are explained. The definitions, terminology and main concepts of IoT platforms are detailed in a clear descriptive way and along with a summary of the main features of each IoT platform that is involved in the project this section represent a pivotal part for the semantic interoperability specification in the full project. Interoperability use cases of the Activage IoT Ecosystem Suite (AIoTES) are described. The last point of this section includes the architecture of the Deployment Sites. Section 4 in this deliverable addresses the Semantic Interoperability concept, and the AIoTES common data model is introduced. Section 5 presents the ACTIVAGE Architecture, on where the IoT Semantic Interoperability Layer is included as a core part of it, and its functionality and internal elements are detailed. All main components of the architecture are described in this section, as architectural building blocks. Also, the interfacing among different blocks is explained. The main objective of this part of the deliverable is shared whose first aiming to efficiently and effectively integrate the platforms and devices of the IoT-AHA Ecosystem and second to provide the guidance for deployment sites on procedures for such integration. Finally, the document ends with the conclusions and the future work.

R-WAKE - Scenario definition document

Scipedia content — Thu, 11 Feb 2021 14:12:57 +0100

This report is Deliverable 2.3 Scenario Definition Document of the R-Wake project, resulting from WP2 activities. It provides the detailed methodology and definition of scenarios to be simulated and analysed in WP5 to generate the new knowledge and evidences of the level of risk and safety due to en-route wake vortex encounters (WVEs) hazards, and to support the proposal of enhancements of separation standards and methods to mitigate that hazards. The scenarios definition elaborates further the research approach identified in deliverable D2.1 System Specification, based in two steps: Step-1 focusses on micro scale modelling, in order to assess the WVE severity level and to obtain a Tolerability Risk Matrix (Safety case baseline); Step-2 focusses on macro-scale modelling of a number of ECAC-wide scenarios, in order to assess the risk and safety level in terms of probability (frequency) of events and mitigation, combining different patterns of traffic demand and ATM constraints, and different types of separation standards and mitigation methods. The R-Wake project addresses the SESAR 2020 Exploratory Research work-programme topic ER-07- 2015 - Separation Management and Separation Standards, within the area of Advanced Air Traffic Services.

Personal Data Analytics: Capturing Human Behavior to Improve Self-Awareness and Personal Services through Individual and Collective Knowledge

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

In the era of Big Data, every single user of our hyper-connected world leaves behind a myriad of digital breadcrumbs while performing her daily activities. It is sufficient to think of a simple smartphone that enables each one of us to browse the Web, listen to music on online musical services, post messages on social networks, perform online shopping sessions, acquire images and videos and record our geographical locations. This enormous amount of personal data could be exploited to improve the lifestyle of each individual by extracting, analyzing and exploiting user's behavioral patterns like the items frequently purchased, the routinary movements, the favorite sequence of songs listened, etc. However, even though some user-centric models for data management named Personal Data Store are emerging, currently there is still a significant lack in terms of algorithms and models specifically designed to extract and capture knowledge from personal data. This thesis proposes an extension to the idea of Personal Data Store through Personal Data Analytics. In practice, we describe parameter-free algorithms that do not need to be tuned by experts and are able to automatically extract the patterns from the user's data. We define personal data models to characterize the user profile which are able to capture and collect the users' behavioral patterns. In addition, we propose individual and collective services exploiting the knowledge extracted with Personal Data Analytics algorithm and models. The services are provided for the users which are organized in a Personal Data Ecosystem in form of a peer distributed network, and are available to share part of their own patterns as a return of the service providing. We show how the sharing with the collectivity enables or improves, the services analyzed. The sharing enhances the level of the service for individuals, for example by providing to the user an invaluable opportunity for having a better perception of her self-awareness. Moreover, at the same time, knowledge sharing can lead to forms of collective gain, like the reduction of the number of circulating cars. To prove the feasibility of Personal Data Analytics in terms of algorithms, models and services proposed we report an extensive experimentation on real world data.

Personal Data Analytics: Capturing Human Behavior to Improve Self-Awareness and Personal Services through Individual and Collective Knowledge

Scipedia content — Tue, 09 Feb 2021 09:33:49 +0100

Creation of new modules in the AirTop simulation environment

Scipedia content — Tue, 09 Feb 2021 09:01:06 +0100

The DESERVE Project:Towards Future ADAS Functions

Scipedia content — Mon, 08 Feb 2021 12:35:23 +0100

Improving Safety and Mobility of Vulnerable Road Users Through ITS Applications

Scipedia content — Mon, 08 Feb 2021 12:33:47 +0100

ITS Applications have in recent years assisted in reducing the number of fatalities in Europe. However, Vulnerable Road Users (VRUs) have not benefited as much as vehicle users. The EU-sponsored VRUITS project assesses the safety and mobility impacts of ITS applications for VRUs, assesses the impacts of current and upcoming ITS applications on the safety and mobility of VRUs, identifies how the usability and efficiency of ITS applications can be improved, and recommends which actions have to be taken at a policy level to improve ITS safety and mobility. This paper describes the results of the first phase of the project, in which the critical scenarios for VRUs are identified starting from accident data analysis, and following a user needs based on focus groups and expert interviews. From this basis, the most promising ITS applications for VRUs are selected according to their potential to address the specific needs of VRUs.

Complex Networks in Air Transport

Scipedia content — Mon, 08 Feb 2021 12:31:48 +0100

Non presente

A Handbook for Governing Hyper-diverse Cities

Scipedia content — Mon, 08 Feb 2021 12:29:56 +0100