Scipedia: Documents published in 2013

A Mobile, Dynamic, and Privacy-Preserving Matching System for Car and Taxi Pools

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

Recently, rates of vehicle ownership have risen globally, exacerbating problems including air pollution, lack of parking, and traffic congestion. While many solutions to these problems have been proposed, carpooling remains one of the most effective approaches. Recently, several carpooling platforms have been built on cloud computing systems, with originators posting online list of departure/arrival points and schedules from which participants can search for rides that match their needs. However, it can be difficult to make matches quickly and the systems are subject to privacy concerns in that they may disclose private information such as names, registration data, and departure/arrival schedules. This paper proposes a dynamic matching method for car/taxi pools for use in mobile devices via ad hoc Wi-Fi networks. The proposed method also preserves user privacy including names and departure/arrival schedules. Moreover, the system does not require the user to register any personal data, so such data cannot be leaked. The system was implemented on the Android mobile platform, allowing users to immediately and securely access the system via their smart phones.

Document type: Article

On the human control of vehicles: an experimental study of acceleration

Scipedia content — Mon, 15 Feb 2021 10:19:35 +0100

This paper presents an experimental investigation of human control of vehicles carried out on the basis of general theories on human movement. The longitudinal and lateral accelerations are studied, and their relations with theories of motor optimality principles, such as minimum jerk, minimum variance, and the two-thirds power law are highlighted. Data have been collected during the final experimental phase of the EU interactIVe project, in which a vehicle developed by Centro Ricerche Fiat has been used to demonstrate driver continuous support produced by an artificial co-driver, within a shared initiative framework. 24 subjects drove the vehicle on a test route twice: once with the system active, the other with the system silent. The test route is composed of urban arterials, extra urban and motorway roads, and takes approximately 40–45 min to be driven. The total database thus amounts to ~35 h of driving data recordings, for a total of ~1.2 M samples per signal. Statistical summary data are presented, which describe human preferred accelerations, correlation between acceleration, curvature, and speed, and between longitudinal and lateral acceleration. Different driving modalities, corresponding to different motor strategies and primitives, are revealed. Comparisons with literature data are also made and discussed. The summary statistics may be useful for the design of future ADAS systems, and indeed they have been collected for the final tuning of the interactIVe co-driver.

Document type: Article

Improving the public transit system for routes with scheduled headways

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

This research contributes to the improvement of the optimal headway solution for the transit performance functions (e. g., minimize total cost; maximize social welfare) derived from the traffic model proposed by Hendrickson. The purpose of this paper is threefold. First, we prove that that model has a unique solution for headway. Second, we offer a formulated approximation for headway. Third, numerical examples illustrate that our formulated approximation performs more accurately than the Hendrickson’s. Keywords : Analytical approach, headway of bus, stop-spacing, public transportation.

Document type: Article

Determination of representative loading conditions for effective semitrailer design

Scipedia content — Mon, 15 Feb 2021 09:52:33 +0100

Obtaining a representative loading spectrum that corresponds well to the reality is still one of the greatest challenges for fatigue life calculations and optimal design of the trailer body. A good qualitative and quantitative knowledge of the spectrum leads to more efficient usage of material, a better design of connection points and an overall decrease of the weight of the trailer, which finally results in a significant decrease in the price of a ton of cargo per km. Despite that, the approach is nowadays mostly based on the experience and rules of thumb. It typically results in over-dimensioning of some parts while other parts remain vulnerable to failure due to unknown loading patterns. This paper describes a generic approach to solve the problems mentioned above applied in a research project named FORWARD (Fuel Optimized trailer Referring to Well Assessed Realistic Design loads). The project lasted two years and was carried out in cooperation with several different trailer manufacturers and 1st tier suppliers. The loading history of more than 1000 hours for five trailer types were captured in the shape of strains, accelerations and velocities of various elements of the trailers, enabling reconstruction of the loading in terms of forces and moments acting on the wheels and kingpin. Parallel to this extensive test-campaign, a novel generic physics-based computational approach was developed to predict selected loads encountered during common manoeuvres to all trailer types. The computational approach was validated against test-data and resulted in creating a generic multibody library applicable for all trailer types, and an automated post-processing routine for the large amount of test-data. First Published Online: 16 Dec 2014

Document type: Article

Seismic behavior of buried pipelines constructed by design criteria and construction specifications of both Korea and the US

Scipedia content — Mon, 15 Feb 2021 09:46:43 +0100

Earthquake loss estimation systems in the US, for example HAZUS (Hazard in US), have been established based on sufficient damage records for the purpose of prevention and efficient response to earthquake hazards; however, in Korea, insufficient data sets of earthquakes and damage records are currently available. In this study, the earthquake damages to pipelines in Korea using the pipeline repair rate (RR) recommended in HAZUS was reevaluated with the degree of confidence when RR is used without modification for the damage estimation of pipelines in Korea. The numerical analyses using a commercial finite element model, ABAQUS, were carried out to compare stresses and strains mobilized in both brittle and ductile pipelines constructed by the design criteria and construction specifications of both Korea and the US. These pipelines were embedded in dense sand overlying three different in situ soils (clay, sand, and gravel) subjected to earthquake excitations with peak ground accelerations (PGAs) of 0.2 to 1.2 g and 1994 Northridge and 1999 Chi-Chi earthquake loadings. The numerical results show that differences in the stress and strain rates are less than 10%. This implies that RR in HAZUS can be used for earthquake damage estimation of pipelines with a 90% confidence level in Korea.

Document type: Article

Information Exchange rather than Topology Awareness: Cooperation between P2P Overlay and Traffic Engineering

Scipedia content — Fri, 12 Feb 2021 16:24:19 +0100

Solutions to the routing strategic conflict between noncooperative P2P overlay and ISP underlay go separate ways: hyperselfishness and cooperation. Unpredictable (possibly adverse) impact of the hyperselfish topology awareness, which is adopted in both overlay routing and traffic engineering, has not been sufficiently studied in the literature. Topology-related information exchange in a cooperatively efficient way should be highlighted to alleviate the cross-layer conflict. In this paper, we first illustrate the hyperselfish weakness with two dynamic noncooperative game models in which hyperselfish overlay or underlay has to accept a suboptimal profit. Then we build a synergistic cost-saving (SC) game model to reduce the negative effects of noncooperation. In the SC model, through information exchange, that is, the classified path-delay metrics for P2P overlay and peer locations for underlay, P2P overlay selects proximity as well as saving traffic transit cost for underlay, and ISP underlay adjusts routing to optimize network cost as well as indicating short delay paths for P2P. Simulations based on the real and generated topologies validate cost improvement by SC model and find a proper remote threshold value to limit P2P traffic from remote area, cross-AS, or cross-ISP.

Document type: Article

Market equilibriums for transport operators with several goals

Scipedia content — Fri, 12 Feb 2021 16:23:07 +0100

The paper addresses a transport market consisting of two firms with goals extending beyond pure profit maximisation. Considering that transport companies often have public owners and that managers have different objective that the owners, it is argued the firms maximise a weighted sum of profits, revenues and total consumer surplus. The paper analyses equilibrium fares and quantities arising from collusion and competition on price (Bertrand) and quantity (Cournot), when the firms produce symmetrically differentiable services and have identical cost and goal functions. Special focus is given to analyzing how the firms’ costs, the degree of substitutability and complementarity between their services and their goal functions influence equilibrium prices in the three different competitive situations. The influence of parameters included in the model regarding the differences between the equilibrium prices is also addressed. The study provides relevant knowledge for transport authorities of how transport firms respond to changes in competitive regimes depending on their objectives and competitive situation.

Document type: Article

Dynamic airspace sectorization via improved genetic algorithm

Scipedia content — Fri, 12 Feb 2021 16:18:34 +0100

This paper deals with dynamic airspace sectorization (DAS) problem by an improved genetic algorithm (iGA). A graph model is first constructed that represents the airspace static structure. Then the DAS problem is formulated as a graph-partitioning problem to balance the sector workload under the premise of ensuring safety. In the iGA, multiple populations and hybrid coding are applied to determine the optimal sector number and airspace sectorization. The sector constraints are well satisfied by the improved genetic operators and protect zones. This method is validated by being applied to the airspace of North China in terms of three indexes, which are sector balancing index, coordination workload index and sector average flight time index. The improvement is obvious, as the sector balancing index is reduced by 16.5 %, the coordination workload index is reduced by 11.2 %, and the sector average flight time index is increased by 11.4 % during the peak-hour traffic.

Document type: Article

Measuring Completeness of Building Footprints in OpenStreetMap over Space and Time

Scipedia content — Fri, 12 Feb 2021 15:07:20 +0100

Due to financial or administrative constraints, access to official spatial base data is currently limited to a small subset of all potential users in the field of spatial planning and research. This increases the usefulness of Volunteered Geographic Information (VGI), in particular OpenStreetMap (OSM), as supplementary datasets or, in some cases, alternative sources of primary data. In contrast to the OSM street network, which has already been thoroughly investigated and found to be practically complete in many areas, the degree of completeness of OSM data on buildings is still unclear. In this paper we describe methods to analyze building completeness and apply these to various test areas in Germany. Official data from national mapping and cadastral agencies is used as a basis for comparison. The results show that unit-based completeness measurements (e.g., total number or area of buildings) are highly sensitive to disparities in modeling between official data and VGI. Therefore, we recommend object-based methods to study the completeness of OSM building footprint data. An analysis from November 2011 in Germany indicated a completeness of 25% in the federal states of North Rhine-Westphalia and 15% in Saxony. Although further analyses from 2012 confirm that data completeness in Saxony has risen to 23%, the rate of new data input was slowing in the year 2012.

Document type: Article

Effectiveness of Variable Message Signs on Driving Behavior Based on a Driving Simulation Experiment

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

Variable message signs (VMSs), as one of the important ITS devices, provide real-time traffic information of road network to drivers in order to improve route choice and relieve the traffic congestion. In this study, the effectiveness of VMS on driving behavior was tested based on a driving simulation experiment. A road network with three levels of VMS location to route-diverging intersection and three types of VMS information format was designed in a high fidelity driving simulator platform. Fifty-two subjects who were classified by driver age, gender, and vocation successfully completed this experiment. The experimental results showed that driver characteristics, VMS location, and information format profoundly influence driving behaviors. Based on the research findings, it is suggested that VMS would be positioned between 150 m and 200 m upstream of the diverging point to balance the VMS effects on traffic safety and operation and the graphic information VMS format is better than the format with text massage only.

Document type: Article

Case study of the real contents delivered in French motorcycle schools

Scipedia content — Fri, 12 Feb 2021 15:01:30 +0100

This study is concerned initial motorcycle training delivered in motorcycle schools in France. Novice motorcyclists are a particularly vulnerable group of road users in Europe and in France. However, scientific attempts to achieve a better understanding of their behaviors have been limited. The potential value of studying initial motorcycle training, both for research purposes and with regard to public policy, is readily apparent. The aims of this paper are to describe the real educational content of training in motorcycle schools and analyze to what extent this content is related to riding after licensing. A case study of all the training process of one trainee (38 hours) was carried out in real world. Audiovisual recordings and interview data of the rider and instructors were collected at each session. This study was supplemented by ethnographic observations of the educational content provided in three motorcycle schools throughout the instructors’ working days. The results that merged from both studies show (1) the riding skills that were fostered (i.e. control skills, and especially emergency skills, in stable and restricted environments) and undervalued (i.e. hazard perception skills, everyday skills) during initial training, and (2) the poverty of observed training settings: learners spend almost all their training time riding in the same setting that is used in the test. In addition to being repeated to excess, these settings are quite different from the real traffic. These results are discussed regarding the scientific literature on motorcycle education. The conclusion presents the implications of these results for public policy in order to design a future rider training system.

Document type: Article

Viscoelastic Model for the Rigid Body Vibrations of a Viaduct Depending on the Support Devices’ Rheological Model

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

Rezumat"/jats:title" "jats:p" Lucrarea abordează comportarea unui model de solid-rigid cu anumite simetrii structurale. Aceste simetrii permit simplificarea calculelor (ecuaţii de mişcare) şi, deci, a modelelor matematice. Dacă solidul rigid este conectat la structură prin patru legături elastice, modelul rămâne încă simplu şi uşor de rezolvat, vibraţiile putând fi decuplate în patru subsisteme de mişcare. "/jats:p" "jats:p"În final, se prezintă un studiu de caz pentru analiza modală a unui viaduct, modelat precum un corp solid-rigid, rezemat elastic, de pe autostrada Transilvania (km 29+602.75 m).

Document type: Article

Thermal Tracking in Mobile Robots for Leak Inspection Activities

Scipedia content — Fri, 12 Feb 2021 14:49:45 +0100

Maintenance tasks are crucial for all kind of industries, especially in extensive industrial plants, like solar thermal power plants. The incorporation of robots is a key issue for automating inspection activities, as it will allow a constant and regular control over the whole plant. This paper presents an autonomous robotic system to perform pipeline inspection for early detection and prevention of leakages in thermal power plants, based on the work developed within the MAINBOT (http://www.mainbot.eu) European project. Based on the information provided by a thermographic camera, the system is able to detect leakages in the collectors and pipelines. Beside the leakage detection algorithms, the system includes a particle filter-based tracking algorithm to keep the target in the field of view of the camera and to avoid the irregularities of the terrain while the robot patrols the plant. The information provided by the particle filter is further used to command a robot arm, which handles the camera and ensures that the target is always within the image. The obtained results show the suitability of the proposed approach, adding a tracking algorithm to improve the performance of the leakage detection system.

Document type: Article

CFD Modeling of Particulates Erosive Effect on a Commercial Scale Pipeline Bend

Scipedia content — Fri, 12 Feb 2021 14:48:43 +0100

The computational fluid dynamics modeling of solid particles hydrodynamic based on the Lagrangian framework for diluted solid-gas flow through 90° gas pipeline bend is carried out to discover the effect of particles size distribution on particles flow pattern and their erosive effect on the bend. Particles size distribution has been obtained experimentally by measuring the sizes of solid particles that are flowing through the gas pipelines of Aghajari gas booster station. Also the erosion rate at the outer wall of the bend is predicted. The pipeline bend under study has a pipe diameter of 56 inches and ratios of the bend radius of the curvature to the pipeline diameter of 1.5. For the validation of computational model, firstly, the computational modeling is performed for a published experimental solid-gas flow data. The computational results include radial gas velocity and radial particle velocity profiles on planes which are at different angles through the bend. The comparison between the predicted numerical results and similar experimental data proves that the predictions of the computational model are acceptable. Finally, the particles' size distributions on each plane through the bend and the erosion rate on the outer wall of the bend have been obtained. The maximum rate of erosion is found to be 3.2 nm/s, occurring between 40 and 65° of the bend.

Document type: Article

Citation counts in transportation research

Scipedia content — Fri, 12 Feb 2021 14:38:36 +0100

In addition to the number of published articles, citation counts are traditionally interpreted as measures of publication merit. They are therefore used to evaluate researchers, research departments, universities and journals. Building on research conducted in scientometrics, we employ data from research articles in transportation research to investigate the influence on article citation counts of article and author characteristics in that particular field of research. Using standard OLS-regression with robust standard errors we find that articles with a high number of references are cited more frequently than articles with fewer references, that articles written by authors from more than one country are more cited than articles written by authors from one country only, and that short-titled articles tend to be more cited than articles with longer titles. To the best of our knowledge this is the first study investigating factors influencing citation counts in transportation research. Implications for researchers, editors and funders are suggested.

Document type: Article

State of art of bus rapid transit transportation

Scipedia content — Fri, 12 Feb 2021 14:38:23 +0100

The increasing importance of the Bus Rapid Transit systems in the last 20 years has given rise to the implementation of several sorts of systems over the world with different characteristics and success levels. This paper aims to describe a global approach of them as well as to carry out an effective comparison in order to achieve outstanding conclusions. From the conceptualization or determination of the main features and evolution of BRT Systems we do a qualitative and quantitative analysis of the currently operating systems according to the development of countries in which they operate in order to identify the key factors for the success of such type of transportation, regarding both its management and users comfort. Comparison between different BRT systems according to their geographical area provides some important evidences. Paper results suggest that we can find two separate groups in BRT systems, on one hand, some countries with more technology and commercial velocity (European, Australian and Americans BRT systems), and on the other hand countries more developed in terms of service, ridership, routes and impact in population. It’s necessary to understand the BRT in the context of the mobility of the city and as long as this system has to compete with other modes of transport the compliance of desirable requirements for a full BRT become more essential.

Document type: Article

How well do different tracers constrain the firn diffusivity profile?

Scipedia content — Fri, 12 Feb 2021 14:27:09 +0100

Firn air transport models are used to interpret measurements of the composition of air in firn and bubbles trapped in ice in order to reconstruct past atmospheric composition. The diffusivity profile in the firn is usually calibrated by comparing modelled and measured concentrations for tracers with known atmospheric history. However, in most cases this is an under-determined inverse problem, often with multiple solutions giving an adequate fit to the data (this is known as equifinality). Here we describe a method to estimate the firn diffusivity profile that allows multiple solutions to be identified, in order to quantify the uncertainty in diffusivity due to equifinality. We then look at how well different combinations of tracers constrain the firn diffusivity profile. Tracers with rapid atmospheric variations like CH₃CCl₃, HFCs and ¹⁴CO₂ are most useful for constraining molecular diffusivity, while &delta:¹⁵N₂ is useful for constraining parameters related to convective mixing near the surface. When errors in the observations are small and Gaussian, three carefully selected tracers are able to constrain the molecular diffusivity profile well with minimal equifinality. However, with realistic data errors or additional processes to constrain, there is benefit to including as many tracers as possible to reduce the uncertainties. We calculate CO₂ age distributions and their spectral widths with uncertainties for five firn sites (NEEM, DE08-2, DSSW20K, South Pole 1995 and South Pole 2001) with quite different characteristics and tracers available for calibration. We recommend moving away from the use of a firn model with one calibrated parameter set to infer atmospheric histories, and instead suggest using multiple parameter sets, preferably with multiple representations of uncertain processes, to assist in quantification of the uncertainties.

Document type: Article

A Method for Multiple Attribute Decision Making Based on the Fusion of Multisource Information

Scipedia content — Fri, 12 Feb 2021 14:24:42 +0100

We propose a new method for the multiple attribute decision making problem. In this problem, the decision making information assembles multiple source data. Two main advantages of this proposed approach are that (i) it provides a data fusion technique, which can efficiently deal with the multisource decision making information; (ii) it can produce the degree of credibility of the entire decision making. The proposed method performs very well especially for the scenario that there exists conflict among the multiple source information. Finally, a traffic engineering example is given to illustrate the effect of our method.

Document type: Article

The Theory of Dynamic Public Transit Priority with Dynamic Stochastic Park and Ride

Scipedia content — Fri, 12 Feb 2021 14:20:07 +0100

Public transit priority is very important for relieving traffic congestion. The connotation of dynamic public transit priority and dynamic stochastic park and ride is presented. Based on the point that the travel cost of public transit is not higher than the travel cost of car, how to determine the level of dynamic public transit priority is discussed. The traffic organization method of dynamic public transit priority is introduced. For dynamic stochastic park and ride, layout principle, scale, and charging standard are discussed. Traveler acceptability is high through the analysis of questionnaire survey. Dynamic public transit priority with dynamic stochastic park and ride has application feasibility.

Document type: Article

Particle size effects on optimal sizing and lifetime of pipelines transporting multi-sized solid-liquid mixtures

Scipedia content — Fri, 12 Feb 2021 14:16:56 +0100

life-cycle cost analysis model is developed in this study, to examine the effects of particle size distribution of the solid particles to be\\ud transported on the optimal sizing and lifetime of the pipelines used for transportation of solid-liquid mixtures. The method determines the lifetime of the pipe corresponding to the least annual total cost per unit length of the pipe. The optimum diameter is obtained so that the total\\ud cost per unit pipe length per unit volume of the transported mixture throughout this lifetime is minimum. The total cost includes manufacturing\\ud and repair cost of pipe, cost of pumping power as well as the cost of power required for the crushing of particles from an initial size distribution to a desirable particle size distribution. The repair cost of pipe and cost of pumping power increase as the pipe becomes older due to more frequent pipe breaks and due to the pipe wear that makes wall roughness, and thereby pressure drop, greater. These costs together with the cost of power for crushing must be considered for through life costing of pipelines. Since the transportation of solid-liquid mixtures is maintained by several pumping stations in long pipelines, the spacing between two successive pumping stations must also be determined. The study shows interdependence of parameters such as the lifetime, the optimum diameter, the corresponding spacing for a given pumping power and the particle size distribution of solid particles transported in the pipeline. Furthermore, the method also provides the interrelation between the total length of pipeline when crushing is economical and the different particle size distributions.

Document type: Article

Sensor-Based Trajectory Generation for Advanced Driver Assistance System

Scipedia content — Fri, 12 Feb 2021 14:03:39 +0100

This paper investigates the trajectory generation problem for an advanced driver assistance system that could sense the driving state of the vehicle, so that a collision free trajectory can be generated safely. Specifically, the problem of trajectory generation is solved for the safety assessment of the driving state and to manipulate the vehicle in order to avoid any possible collisions. The vehicle senses the environment so as to obtain information about other vehicles and static obstacles ahead. Vehicles may share the perception of the environment via an inter-vehicle communication system. The planning algorithm is based on a visibility graph. A lateral repulsive potential is applied to adaptively maintain a trade-off between the trajectory length and vehicle clearance, which is the greatest problem associated with visibility graphs. As opposed to adaptive roadmap approaches, the algorithm exploits the structured nature of the environment for construction of the roadmap. Furthermore, the mostly organized nature of traffic systems is exploited to obtain orientation invariance, which is another limitation of both visibility graphs and adaptive roadmaps. Simulation results show that the algorithm can successfully solve the problem for a variety of commonly found scenarios.

Document type: Article

The fate of an oil spill in São Sebastião channel: a case study

Scipedia content — Fri, 12 Feb 2021 13:54:48 +0100

n oil pipeline ruptured in May 1994 and 2 700 tons of crude oil leaked into the São Sebastião Channel, affecting several neighboring areas. A program for the monitoring of hydrocarbons in sediments, using the gas chromatography / flame ionization detector methodology, was being undertaken in the area at the time. The data obtained were compared to those of samples collected after the accident to determine the fate of the oil spilled and ascertain its contribution to the environment. The earlier results showed that hydrocarbons were introduced from two different sources: biogenic, mainly from terrestrial plants, and anthropogenic, as oil, in sewage and from shipping. The later data indicated that the site closest to the pipeline rupture had been the most affected. Following that, two stations located at the north entrance of the channel presented the highest n-alkane concentrations, suggesting that the northeasterly wind-driven currents had carried the oil northward. Seven months later, one of these stations, a high-energy site, showed some signs of recovery, but this process was not observed at the other, which seemed to be a low-energy site. In conclusion, the data showed that the aliphatic hydrocarbon analyses were powerful tools for the assessment of the fate of the oil spill and that the northern part of the São Sebastião Channel is more subject to the effects of oil spills. A ruptura de um oleoduto em maio de 1994 introduziu 2.700 tons de óleo cru no Canal de São Sebastião, contaminando algumas áreas. Na ocasião um monitoramento de hidrocarbonetos em sedimentos estava sendo realizado na região, utilizando o método de cromatografia em fase gasosa/ detecção por ionização de chama. Os dados obtidos nesse monitoramento foram comparados aos resultados das amostras coletadas logo após o acidente, com o objetivo de verificar a extensão da contaminação por óleo e os lugares mais atingidos. Os dados prévios mostraram duas fontes de introdução de hidrocarbonetos: biogênica, com predomínio de plantas superiores, e antrópica, causada por atividades náuticas e esgotos. Os dados posteriores mostraram que a estação de coleta mais próxima ao oleoduto foi a mais atingida. Na sequencia, as duas estações localizadas na entrada norte do canal apresentaram as maiores concentrações de n-alcanos, sugerindo que as correntes NE, impulsionadas pelo vento, transportaram o óleo no sentido norte do canal. Sete meses depois uma destas estações, aquela situada em local de alta energia, mostrou sinais de recuperação, o que, contudo, não foi observado na outra, considerada de ambiente deposicional. Em conclusão, pode-se afirmar que análises de hidrocarbonetos são ferramentas poderosas para avaliar o destino de um óleo e que a parte norte do Canal de São Sebastião tem maior probabilidade de ser afetada na ocasião de um derrame de óleo.

Document type: Article

Class-Based Constraint-Based Routing with Implemented Fuzzy Logic in MPLS-TE Networks

Scipedia content — Fri, 12 Feb 2021 13:50:57 +0100

The paper deals with constraint-based routing (CBR) in MPLS-TE networks and proposes a new CBR algorithm based on fuzzy logic called Fuzzy Class-Based Algorithm (FCBA). Multiprotocol label switching with traffic engineering (MPLS-TE) networks represent a popular mechanism to effectively use resources of service providers’ core networks. The paths can be either built by administrators (explicit routing) or built by using existing routing algorithms which mostly decide based on the shortest paths towards the destination which might not be sufficient in nowadays’ multimedia networks. To address this problem various CBR algorithms have emerged which take into consideration various aspects important to existing traffic like QoS parameters or administrative policies. FCBA makes routing decisions based on traffic classes and by using fuzzy logic we can assign normalized values to various constraints based on the traffic class’ preferences (e.g., low delay paths for voice traffic) and network administrator’s preferences (e.g., avoiding congested links). The paper provides comparison of FCBA with existing CBR approaches based on their ability to provide QoS parameters loss. The simulations show that FCBA provides the best results for the highest priority traffic where it uses lower priority traffic to efficiently utilize the network.

Document type: Article

Using random forests to diagnose aviation turbulence.

Scipedia content — Fri, 12 Feb 2021 13:44:10 +0100

mospheric turbulence poses a significant hazard to aviation, with severe encounters costing airlines millions of dollars per year in compensation, aircraft damage, and delays due to required post-event inspections and repairs. Moreover, attempts to avoid turbulent airspace cause flight delays and en route deviations that increase air traffic controller workload, disrupt schedules of air crews and passengers and use extra fuel. For these reasons, the Federal Aviation Administration and the National Aeronautics and Space Administration have funded the development of automated turbulence detection, diagnosis and forecasting products. This paper describes a methodology for fusing data from diverse sources and producing a real-time diagnosis of turbulence associated with thunderstorms, a significant cause of weather delays and turbulence encounters that is not well-addressed by current turbulence forecasts. The data fusion algorithm is trained using a retrospective dataset that includes objective turbulence reports from commercial aircraft and collocated predictor data. It is evaluated on an independent test set using several performance metrics including receiver operating characteristic curves, which are used for FAA turbulence product evaluations prior to their deployment. A prototype implementation fuses data from Doppler radar, geostationary satellites, a lightning detection network and a numerical weather prediction model to produce deterministic and probabilistic turbulence assessments suitable for use by air traffic managers, dispatchers and pilots. The algorithm is scheduled to be operationally implemented at the National Weather Service's Aviation Weather Center in 2014.

Document type: Article

High Confidence Networked Control for Next Generation Air Transportation Systems

Scipedia content — Fri, 12 Feb 2021 13:35:03 +0100

This paper addresses the design of a secure and fault-tolerant air transportation system in the presence of attempts to disrupt the system through the satellite-based navigation system. Adversarial aircraft are assumed to transmit incorrect position and intent information, potentially leading to violations of separation requirements among aircraft. We propose a framework for the identification of adversaries and malicious aircraft, and then for air traffic control in the presence of such deliberately erroneous data. The framework consists of three mechanisms that allow each aircraft to detect attacks and to resolve conflicts: fault detection and defense techniques to improve Global Positioning System (GPS)/inertial navigation, detection and defense techniques using the Doppler/received signal strength, and a fault-tolerant control algorithm. A Kalman filter is used to fuse high frequency inertial sensor information with low frequency GPS data. To verify aircraft position through GPS/inertial navigation, we propose a technique for aircraft localization utilizing the Doppler effect and received signal strength from neighboring aircraft. The control algorithm is designed to minimize flight times while meeting safety constraints. Additional separation is introduced to compensate for the uncertainty of surveillance information in the presence of adversaries. We evaluate the effect of air traffic surveillance attacks on system performance through simulations. The results show that the proposed mechanism robustly detects and corrects faults generated by the injection of malicious data. Moreover, the proposed control algorithm continuously adapts operations in order to mitigate the effects these faults. The ability of the proposed approaches to defend against attacks enables reliable air traffic operations even in highly adversarial surveillance conditions.

National Science Foundation (U.S.) (CNS-931843)

United States. Office of Naval Research. Multidisciplinary University Research Initiative (Grant N0014-08-0696)

United States. Office of Naval Research. Multidisciplinary University Research Initiative (Grant N00014-09-1-1051)

United States. Office of Naval Research (Grant N00014-12-1-0609)

United States. Air Force Office of Scientific Research. Multidisciplinary University Research Initiative (Grant FA9550-10-1-0567)

Document type: Article

Planning logistics network for recyclables collection

Scipedia content — Fri, 12 Feb 2021 13:31:14 +0100

Rapid urbanization, intensified industrialization, rise of income, and a more sophisticated form of consumerism are leading to an increase in the amount and toxicity of waste all over the world. Whether reused, recycled, incinerated or put into landfill sites, the management of household and industrial waste yield financial and environmental costs. This paper presents a modeling approach that can be used for designing one part of recycling logistics network through defining optimal locations of collection points, and possible optimal scheduling of vehicles for collecting recyclables. [Projekat Ministarstva nauke Republike Srbije, br. TR36005]

Document type: Article

Application of the Expanded Theory of Planned Behavior in Intercity Travel Behavior

Scipedia content — Fri, 12 Feb 2021 13:17:25 +0100

Congestion in intercity corridors of metropolitan area has been increasing steadily. To alleviate congestion, many major investment projects, such as the high speed railway projects, were proposed by agency. To evaluate the adequacy and efficiency of these projects, the intercity travel behavior should be analyzed in metropolitan area. The paper constructed a Multiple Indicators and Multiple Causes (MIMIC) model according to an expanded theory of planned behavior (TPB) to study the travel behavior of choosing from the choice set of the traditional train, the high speed railway and the coach by demographic and psychological factors. Through empirical data collection and analysis, we found that demographic factors of travelers indeed positively engender the latent variables in MIMIC, and descriptive norm and habit had direct or indirect significant effect on travel behavior and intention. On the basis of the effect of psychological constructors of the expanded TPB on the intercity travel behavior and differentiation of traveler's demographic characteristics, the agency can make reasonable policies and proper information for the intercity transportation. The results will support the basic theory of optimizing the transportation system in metropolitan area. Implications for researchers and suggestions for future research are also addressed in this study.

Document type: Article

New And Existing Bridge Constructions - Increase of Fatigue Strength of Welded Joints by High Frequency Mechanical Impact Treatment

Scipedia content — Fri, 12 Feb 2021 13:14:35 +0100

Numerous studies at KIT prove that high frequency mechanical impact (HFMI) treatment is an efficient method for increasing the fatigue strength of welded steel structures. Within different research projects it was found that HFMI-methods can be used successfully for new and existing structures in order to extend the fatigue life. This paper gives an overview of the current status of existing steel bridges in Germany regarding aspects like bridge age distributions and traffic loads. Based on that overview welded joints susceptible to fatigue failure are identified. Using component-like small scale specimens, HFMI-methods were investigated within the objective of implementing an effective application for new and existing structures. Applying the fatigue test data observed, existing design proposals are evaluated and design recommendations for HFMI-treated joints are given. As a result of the research work, a transfer into practice has been realized and different applications are illustrated using the example of bridge constructions made of steel.

Document type: Article

A methodology to compute emission projections from road transport (EmiTRANS)

Scipedia content — Fri, 12 Feb 2021 13:01:10 +0100

mospheric emissions from road transport have increased all around the world during the last decades more rapidly than from other pollution sources. For instance, they contribute to more than 25% of total CO, CO2, NOx, and fine particle emissions in most of the European countries. This situation shows the importance of road transport when complying with emission ceilings and air quality standards applied to these pollutants. This paper presents a modelling system to perform atmospheric emission projections (simultaneously both air quality pollutants and greenhouse gases) from road transport including the development of a tailored software tool (EmiTRANS) as a planning tool. The methodology has been developed with two purposes: 1) to obtain outputs used as inputs to the COPERT4 software to calculate emission projections and 2) to summarize outputs for policy making evaluating the effect of emission abatement measures for a vehicle fleet. This methodology has been applied to the calculation of emission projections in Spain up to 2020 under several scenarios, including a sensitivity analysis useful for a better interpretation and confidence building on the results. This case study demonstrates the EmiTRANS applicability to a country, and points out the need for combining both technical and non-technical measures (such as behavioural changes or demand management) to reduce emissions, indirectly improving air quality and contributing to mitigate climate change.

Document type: Article

Quantifying the impact of road lighting on road safety — A New Zealand Study

Scipedia content — Fri, 12 Feb 2021 12:40:47 +0100

It is well known from the literature that road lighting has significant safety benefits. The NZTA Economic Evaluation Manual (EEM) quotes a 35% reduction in crashes as the effect of upgrading or improving lighting where lighting is poor.However, no well-established dose–response relationship to lighting parameters exists from which one can deduce benchmark levels of lighting for safety.This study looked at a sample of street lighting installations spread over the urban areas of nine territorial local authorities. Standard street lighting parameters were measured in the field using a variety of instruments including illuminance meter, luminance meter and digital camera. Field measurements were related to the ratio of night-time to day time crashes as a measure of night time safety vis-a-vis daytime safety.A statistically significant dose–response relationship was found between average road luminance and safety across all traffic volume groups, with an indication that the relationship may be stronger where more serious crashes are involved.Threshold increment was also a significant variable but not so longitudinal uniformity or overall uniformity.The results related to luminance will allow practitioners to better estimate the safety benefits of different levels of lighting resulting in better targeting of expenditure.

Document type: Article

Coupling between power systems and pipelines during geomagnetic disturbances

Scipedia content — Thu, 11 Feb 2021 14:42:45 +0100

DISTRIBUCIÓN URBANA DE MERCANCÍAS: DESCRIPCIÓN Y CLASIFICACIÓN DE SOLUCIONES EXISTENTES E IMPLEMENTACIÓN DE DOS SOLUCIONES NOVEDOSAS

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

En este trabajo se describen y clasifican las soluciones existentes para la distribución urbana de mercancías (DUM) y se proponen dos soluciones novedosas aplicables a la DUM. La descripción de las soluciones proviene de una extensa revisión de la literatura existente. La clasificación de las soluciones existentes es fruto del análisis realizado por los autores, gracias al cual se propone una nueva clasificación en 6 categorías distintas. En cuanto a las soluciones novedosas, se describen y se analiza su utilidad mediante dos pruebas piloto en España en establecimientos de las enseñas Eroski, Caprabo y Mercadona. A lo largo de las pruebas piloto queda patente que dichas dos soluciones pueden ser de gran utilidad para el sector de la DUM. In this paper we describe and classify the existing measures for urban freight distribution (DUM) and we propose two new solutions applicable to the DUM. The description of the solutions comes from an extensive review of the literature and the classification from the analysis made by the authors on the existing measures. The new solutions are described and its utility is analyzed by two pilot tests carried on several Eroski and Mercadona Caprabo stores. During pilot testing has become clear that these two solutions can be very useful to the field of DUM.

The Influence of Time-criticality on Situation Awareness when Retrieving Human Control after Automated Driving

Scipedia content — Mon, 08 Feb 2021 10:23:28 +0100

When applying automated driving as a means for congestion assistance, developers are challenged how to accommodate the transitions between automated and manually driving, especially because these transitions might occur regularly and suddenly. During automated driving, the ability to take over control is also aggravated due to the driver being placed out of the control-loop. To assess then the ability to retrieve human control, we tested within a driver simulator experiment the influence of criticality (available time) on Situation Awareness (SA) gained during time-critical take-overs within a scenario of congested driving. Though one of the applied measurement methods did not show the expected effect of SA on successfulness of taking back control, the results show that drivers are able to successfully retrieve control, also within time-critical situations. Furthermore, the results show that the ability to retrieve control is positively influenced if drivers gain increased levels of SA.

Harmonic distortions of multiple power factor compensated EV chargers

Scipedia content — Mon, 08 Feb 2021 10:23:13 +0100

ICT-power co-simulation platform for the analysis of communication-based volt/var optimization in distribution feeders

Scipedia content — Mon, 08 Feb 2021 10:21:59 +0100

The paper presents an ICT and power co-simulation platform for the analysis of the volt/var control and relevant optimization in medium voltage distribution feeders, achieved by means of a system of distributed controllers coordinated via a shared band-limited digital communication network. The platform has been built by realizing the interface between two specific simulation environments: the Electromagnetic Transient Program EMTP-RV and the communication network simulator Opnet Modeller. The preliminary results provide basic indications on the expected performances of the considered communication-based strategies for different traffic congestion levels and load/generation dynamic variations.

Driving without anxiety: A route planner service with range prediction for the electric vehicles

Scipedia content — Mon, 08 Feb 2021 10:05:31 +0100

In modern smart cities, mobility based on Electric Vehicles (EVs) is considered a key factor to reduce carbon emissions and pollution. However, despite the global interest and the investments worldwide, the user acceptance level is still low, mainly due to the lack of charging services support. This is one of the main causes for the so called “EV driver's anxiety”, and has led people to consider EV mobility suitable only for short routes. To contrast this issue, we propose here a route planner application supporting EV mobility also on medium and long routes, through prediction of range and charging stops. Our application estimates the minimal energy consumption path, by also considering the overhead to reach the charging stations along the way towards the destination. We demonstrate the optimality of the algorithm and we describe its implementation within a Web-application which connects to charging providers' services (to retrieve the locations of charging spots) and to Google services (for routing directions and real-time traffic data). Finally, we evaluate the scalability of our application, and we study its effectiveness in supporting EV routes on large-scale scenarios (e.g. the Emila-Romagna region in Italy) through immersive simulation techniques.

Preliminary investigations on automatic detection of leaks in water distribution networks by means of vibration monitoring

Scipedia content — Mon, 08 Feb 2021 10:03:18 +0100

The efficiency of water supply networks is an important issue. In order to reduce water losses, policies of leak reduction are essential. The paper deals with a preliminary study on the use of vibration monitoring tools for the detection of leaks in water service pipelines. The long-term project is the development of a system for automatically detecting burst leaks occurring in service pipes. Preliminary experimental tests were performed on both a test rig and an actual service pipe of the water distribution system. Three main objectives were achieved: firstly, the effectiveness of vibration monitoring for leak detection purposes was assessed providing a positive response; then, a prototypal detection procedure was studied, implemented and tested on the preliminary experimental data; finally, the specifications for a prototypal acquisition equipment were also determined. This paper illustrates the experimental campaign and its main results.

Estimating the harmonic distortions in a distribution network supplying EV charging load using practical source data - Case example

Scipedia content — Mon, 08 Feb 2021 10:02:53 +0100

A mobile application to assist electric vehicles' drivers with charging services

Scipedia content — Mon, 08 Feb 2021 09:58:36 +0100

Electric Vehicles (EVs) represent one of the most promising solutions toward sustainable transportation systems. However, some aspects of EV-based mobility pose challenges for a larger market uptake. Among the others, the overhead of charging operations (e.g. Long recharge time), and the lack of accurate information about availability of EV supply stations (EVSSs) while being on board of an EV are perceived by customers as important limitations, and determine a low user acceptance. To tackle these issues, additional assistance must be provided to EV drivers, through the utilization of ICT-based solutions. In this paper, we describe the implementation of a mobile Android application, which has been deployed within the EU Internet of Energy (IoE) project, with the goal of supporting a larger uptake of EV-based mobility. The application provides full assistance to EV drivers, through functionalities of battery monitoring, dynamic range prediction, and EVSS discovery along the way. Moreover, it supports the IoE semantic architecture, and allows EV drivers reserving a charging slot based on their preferences, and on current availability of EVSSs. The user acceptance of the application has been tested through a questionnaire. Test results confirm the importance of charging reservation mechanisms to mitigate EV driver anxiety problems.

The Role of Methane Hydrates in the Failure of a Gas Pipeline

Scipedia content — Mon, 08 Feb 2021 09:53:45 +0100

Gas hydrates are known to form plugs in pipelines. Gas hydrates are crystalline compounds that form when hydrocarbons such as methane come in contact with water under thermodynamical opportune conditions, as high pressure and low temperature. Hydrates, like any obstruction in a pipeline, reduce flow, increase back pressure in the system and increase the differential pressure across the obstruction. When the line section is obstructed by a plug, the differential pressure can put the hydrate in movement and quickly accelerate it up to a speed approaching that of sound; in this case, the moving mass can cause serious mechanical damages at downstream locations where the plug can also meet restrictions or obstacles such as valves, elbows or tees. In this paper a real case of a gas pipeline failure, due to the presence of a moving mass of methane hydrate, has been investigated by considering an analytical and numerical modeling of the motion of the hydrates, as well as of their impact against the pipes.

Experimental Study of Slug Characteristics: Implications to Sand Erosion

Scipedia content — Mon, 08 Feb 2021 09:52:32 +0100

Sand erosion is a severe problem that many oil and gas producers have to deal with. Therefore, it is desirable to have a model that can predict erosion for various operating conditions. Predicting erosion is a complex problem due to the number of parameters that are involved. The complexity of predicting erosion increases when producing or transporting multiphase fluids through pipelines. It is well known that the characteristics of multiphase flow affect sand erosion in the pipelines. This work specifically concentrates on investigating multiphase-slug characteristics using a measurement technique based on Wire Mesh Sensor. A 16 × 16 dual Wire Mesh Sensor is installed before a standard 76.2 mm (3-inch) elbow for a horizontally oriented pipe. The distance by which the dual Wire Mesh Sensors are separated is 32 mm. The local void fraction is extracted where horizontal and vertical wires of the sensor intersect, utilizing the differences in conductance between gas and liquid as they pass through the crossings of the wires. The fluids used in these multiphase experiments were air and either water or water-Carboxy Methyl Cellulose mixture to increase the liquid viscosity. Experiments were conducted, where superficial gas velocity ranged from 9.1 m/s to 35 m/s, and superficial liquid velocity was 0.76 m/s. Three different liquid viscosities (1 cP, 10 cP and 40 cP) were used for performing the experiments. The void fraction data obtained using the dual Wire Mesh Sensors is utilized to achieve the interfacial velocities of the liquid slug. Further analysis of the data is conducted to obtain other slug characteristics such as the liquid slug body length distribution and frequency of the slugs. Additionally, liquid slug fronts and slug tails were identified. The differences in the characteristics of slug flow and pseudo-slug flow are addressed. Finally, the slug characteristics were utilized in order to enhance the understanding of sand particle impact velocities with the pipe wall and the resulting erosion in the horizontal pipelines and elbow.Copyright © 2013 by ASME

Electronic decal: a security function based on V2X communication

Scipedia content — Mon, 08 Feb 2021 09:51:56 +0100

New technologies such as vehicle-to-X (V2X) communication and advanced driver assistance systems (ADAS) are on the rise. They are mainly used to increase road safety as well as traffic efficiency and to provide customers with infotainment features. However, these new technologies also provide the opportunity to combat vehicle related crime which is present in our society. In this paper, we summarize current measures tackling vehicle related crime and propose a security function, namely electronic decal, based on V2X communication to combat vehicle theft. Furthermore, we propose an integration of the electronic decal functionality into the message format based on the latest standardization progress of the European Telecommunications Standards Institute (ETSI).

Receding horizon multi-vehicle routing for emergency scenarios

Scipedia content — Mon, 08 Feb 2021 09:49:04 +0100

This paper deals with dynamic Multi-Vehicle Routing Problem in both deterministic and stochastic scenarios; the objective is to find the best paths for a fleet of vehicles, with the aim of visiting a set of targets. Based on the Cooperative Receding Horizon approach proposed in [4] for the Euclidean case, this paper i) develop a routing algorithm for graph-represented mission spaces, ii) presents a switching algorithm, which is able to dynamically change the vehicle behaviour according to the time-variable configuration of both vehicles and targets, as well as to handle the discovery of unknown targets. Simulations show the algorithm effectiveness.

Bird Strike Warning System

Scipedia content — Mon, 08 Feb 2021 09:44:35 +0100

Boeing;Gulfstream;Lockheed Martin;Aerospace America;Aviation Week;et al 2013 Aviation Technology, Integration, and Operations Conference -- 12 August 2013 through 14 August 2013 -- Los Angeles, CA -- 99255 Safety is an important and indispensable factor at aviation. Bird strike to aircraft affects and decreases the safety of aviation. Bird strike events increase due to the increasing air traffic demand and number of birds settling around the airports. Bird strikes put the flight safety at risk and also cause million dollars of damage, therefore So requirement for a warning system against them has been increasing day by day. In this study, a novel warning system that uses image processing techniques is proposed as an alternative to the conventional systems against to the bird strike events. At this warning system, background subtraction algorithm is used to produce a visual warning for the bird strike risk to alert the air traffic controller at the airports. In this paper a conceptional design of such a bird strike warning system with image processing is carried out. The desired system will have an embedded platform and two stationary cameras. The cameras will be placed the both ends of runways. By this way the system can detect the birds in two most important regions; inside the final approach course and initial climb area. It is known that most of the bird strikes primarily take place in these regions. In this way bird strike risk can be decreased especially in these regions.

Electric vehicle charger load current harmonics variations due to supply voltage level differences — Case examples

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

Airspace design with explicit utilization of convective weather forecast data for reduced traffic flow management actions

Scipedia content — Mon, 08 Feb 2021 09:42:01 +0100

We demonstrate a method for airspace design that makes explicit use of weather forecast data, in addition to forecasted traffic data, to design sectors that potentially permit reduced traffic flow management actions. We use a local geometric optimization method to partition a portion of airspace into sectors while optimizing not only for load balancing, flow conformance and sector geometry, but also for providing lane options with respect to the weather forecast data.

Pedestrian crossing prediction using multiple context-based models

Scipedia content — Mon, 08 Feb 2021 09:40:13 +0100

In inner-city, most vehicle-pedestrian collisions occur when a pedestrian is crossing the road and the driver does not see or pay attention to him. Current ADAS (advanced driver assistance systems) warn the driver or apply the brakes shortly before the collision, but in some situations the collision cannot be fully avoided because most systems react only when the pedestrian is already in front of the vehicle. To fully avoid a collision, a driver should be warned earlier. Behavior prediction is a solution that can be used to warn a driver before the pedestrian starts crossing. In this paper, the authors propose a generic context based model to predict crossing behaviors of pedestrians in inner-city. They will show that this model provides accurate prediction at an early time. However, there are specific locations such as zebra crossings, where based on expert driving experience, one would expect that a prediction can be done even earlier. Therefore, the authors have developed an additional specific model fitted to the context of zebra crossings. The experiments show that this model produces both, better and earlier predictions in this specific context. Because the goal is to build a generic crossing prediction system, the authors finally apply the framework of the `Context Model Tree' to combine the two models. We demonstrate that this multi-model system is well suited to provide early predictions for realistic data, including both, generic inner-city situations and zebra crossings.

T-Watcher: A New Visual Analytic System for Effective Traffic Surveillance

Scipedia content — Wed, 03 Feb 2021 22:01:51 +0100

Nowadays, big cities are suffering from severe traffic congestion as a result of the continuing increase in vehicles. Taxis equipped with GPS can be viewed as sensors of the traffic situation in city. However, trajectory data generated by taxi's GPS traces are often high-dimensional and contain large spatial and temporal attributes, which pose challenges for analysts. In this paper, based on taxi trajectory data, we present an interactive visual analytics system, T-Watcher, for monitoring and analyzing complex traffic situations in big cities. Users are able to use a carefully designed interface to monitor and inspect data interactively from three levels (region, road and vehicle views). We develop a visualization method to monitor and analyze traffic patterns for abnormal behaviors detection. In the region view of our system, global temporal changes in spatial evolution will be presented to users and can be interactively explored. The road view shows temporal changes to the traffic situations of significant segments of roads. The vehicle view uses a novel visualization method to track individual vehicles. Furthermore, the three views integrate important statistical and historical information related to traffic, which illustrate temporal changes of the traffic. We find that this design can help users explore historical information while monitoring traffic. We test our system on a real-life vehicle dataset collected from thousands of taxis and obtained some interesting findings. The experimental results confirm the effectiveness and efficiency of the proposed visual detection method. The analysis of the results also shows that our system is capable of effectively monitoring traffic and detecting abnormal traffic patterns.

Living lab electric vehicles flanders (Belgium): The influence of testing an EV on the general appreciation of electric mobility

Scipedia content — Wed, 03 Feb 2021 21:58:07 +0100

Numerous studies have already demonstrated the benefits and social relevance of electric vehicles. But why EVs are not yet visible in our streets? To provide an answer to this question the Flemish government has set up five living labs for the deployment of electric vehicles in 2011. Several studies presented in literature are focused on the consumer and his/her perception, but rarely take into account whether the consumer actually drove an EV. Therefor the iMove- and EVA-platform, as part of The Living Labs, form the ideal environment to investigate the perception of test users. Test drivers were asked to fill-in a same questionnaire before and after the test. Questions included inter alia judging the possible advantages and disadvantages, purchase potential. Many people were interested to test an electric car, although there basic knowledge about EVs was poor. Consumers confirm that the lower cost per kilometer is an important advantage, although it became less crucial after testing. Charging at home is perceived as an important advantage. The limited electric range still remains the main disadvantage, followed by the high purchase price. Consumers clearly underestimated the effect of a limited range. The willingness to purchase an EV within the future is related to the consumer’s idea of when an EV will be a full alternative. The majority consider buying an electric car in the near future (within 4 years). Related to this, one-third of the test population is willing to pay more for an electric car.

Document type: Article

Application-Aware Aggregation and Traffic Engineering in a Converged Packet-Circuit Network

Scipedia content — Wed, 03 Feb 2021 21:54:45 +0100

We demonstrate a converged OpenFlow enabled packet-circuit network, where circuit flow properties (guarantee d bandwidth, low latency, low jitter, bandwidth-on-demand, fast recovery) provide differential treatment to dynamically aggregated packet flows for voice, video and web traffic.

Optimal Terminal Area Flow Control Using Eulerian Traffic Flow Model

Scipedia content — Wed, 03 Feb 2021 21:51:39 +0100

Development of a terminal area flow control algorithm suitable for use as a controller decision support tool is presented. Using the available traffic data, the control algorithm determines the miles-in-trail required at the metering fixes to deliver a desired traffic flow rate on the runway based on an Eulerian model. The present research is motivated by the NASA System Oriented Runway Management program. Eulerian models have been previously advanced for use in en-route air traffic flow control. In the present work, the parameters of the Eulerian model are derived from a Bayesian estimator using real-time traffic data. The Eulerian model is then used in conjunction with optimal control theory to derive the control law. The optimality criterion is chosen as a weighted sum of the deviations between desired runway flow rates and the miles-in-trail of the aircraft arriving at the metering fixes. The tracking performance of the algorithm is illustrated for traffic arriving into the San Francisco Metroplex as well as in the Los Angeles Metroplex. Simulation results demonstrate that the proposed approach provides actionable decisions for selecting miles-intrail control for satisfying specified airport arrival rates.

Optimization of Robust Header Compression for aeronautical communication

Scipedia content — Wed, 03 Feb 2021 21:46:36 +0100

The ceaselessly growing requests for communication capacity in the aeronautical sector will soon result in an excess of the current Air Traffic Control (ATC) capacity limitations. To cope with this issue, current research activities, such as the EU FP7 SANDRA project, investigate new seamless IPv6-based network solutions which integrate the different aeronautical services. These solutions will generate a significant protocol overhead due to all the required network functionalities. Within this paper, the focus is on the insertion of RObust Header Compression (ROHC) in the SANDRA architecture to reduce the protocol overheads. Performance evaluations for the usage of ROHC in the aeronautical context are provided and a strong emphasis of this work is put on a discussion on how ROHC parameters can be optimized for operational aeronautical communication.

Quasi-dynamic Traffic Light Control for a Single Intersection

Scipedia content — Wed, 03 Feb 2021 21:46:10 +0100

We address the traffic light control problem for a single intersection by viewing it as a stochastic hybrid system and developing a Stochastic Flow Model (SFM) for it. We adopt a quasi-dynamic control policy based on partial state information defined by detecting whether vehicle backlog is above or below a certain threshold, without the need to observe an exact vehicle count. The policy is parameterized by green and red cycle lengths which depend on this partial state information. Using Infinitesimal Perturbation Analysis (IPA), we derive online gradient estimators of an average traffic congestion metric with respect to these controllable green and red cycle lengths when the vehicle backlog is above or below the threshold. The estimators are used to iteratively adjust light cycle lengths so as to improve performance and, in conjunction with a standard gradient-based algorithm, to seek optimal values which adapt to changing traffic conditions. Simulation results are included to illustrate the approach and quantify the benefits of quasidynamic traffic light control over earlier static approaches.

Comment: arXiv admin note: substantial text overlap with arXiv:1204.1910

Generic driver intent inference based on parametric models

Scipedia content — Wed, 03 Feb 2021 21:39:22 +0100

Reasoning about the driver intent is fundamental both to advanced driver assistance systems as well as to highly automated driving. In contrast to the vast majority of preceding work, we investigate an architecture that can deal with arbitrary combinations of subsequent maneuvers as well as a varying set of available features. Detailed parametric models are given for the indicator, velocity and gaze direction features, all of which are parametrized from the results of extensive user studies. Evaluation is carried out for continuous right-turn prediction on a separate data set. Assuming conditional independence between the individual feature likelihoods, we investigate the contribution of each feature to the overall classification result separately. In particular, the approach is shown to work well even when faced with implausible observations of the indicator feature.

ROThAr: Real-Time On-Line Traffic Assignment with Load Estimation

Scipedia content — Wed, 03 Feb 2021 21:37:43 +0100

eer-reviewed More and more drivers use on-board units to help them navigate in the increasing urbanised environment they live and work in. These system (e.g., routing applications on smart phones) are now very often on-line, and use information from the traffic situation (e.g., accidents, congestion) to get the best route. We can now envisage a world where all trips are assigned and updated by such an on-line system, making the best routing decisions based on traffic conditions. The problem is that current systems consider only ???local??? elements (e.g., driver preference and current traffic condition) and do not make routing decisions from a global perspective. This can lead to a lot of similar routing assignments that could lead to further traffic congestion. The objective of the next generation on-line navigation systems is then to come up with a ???smart???, real-time route assignment, which balances the load between the different road segments and offers the best quality to the drivers. However, every routing decision made has an impact on the traffic conditions (one more vehicle on the road segments selected) and computing the load induced by the trips is a computationally heavy problem. This paper addresses this question of real-time on-line traffic assignment, and shows that under certain conditions it is possible to have (i) an accurate estimation of the load and travel time on every road segment and (ii) an optimised traffic assignment that adapts to divergence and evolutions (e.g., accidents) of the system.

Delay-Robustness of Transfer Patterns in Public Transportation Route Planning

Scipedia content — Wed, 03 Feb 2021 21:37:17 +0100

International audience; Transfer pattern routing is a state-of-the-art speed-up technique for finding optimal paths which minimize multiple cost criteria in public transportation networks. It precomputes sequences of transfer stations along optimal paths. At query time, the optimal paths are searched among the stored transfer patterns, which allows for very fast response times even on very large networks. On the other hand, even a minor change to the timetables may affect many optimal paths, so that, in principle, a new computation of all optimal transfer patterns becomes necessary. In this paper, we examine the robustness of transfer pattern routing towards delay, which is the most common source of such updates. The intuition is that the deviating paths caused by typical updates are already covered by original transfer patterns. We perform experiments which show that the transfer patterns are remarkably robust even to large and many delays, which underlines the applicability and reliability of transfer pattern routing in realistic routing applications.

Variability-aware design of energy-delay optimal linear pipelines operating in the near-threshold regime and above

Scipedia content — Wed, 03 Feb 2021 21:34:45 +0100

Soft-edge flip-flop based pipelines can improve the performance and energy efficiency of circuits operating in the super-threshold (supply voltage) regime by allowing opportunistic time borrowing. The application of this technique to near-threshold regime of operation, however, faces a significant challenge due to large circuit parameter variations that result from manufacturing process imperfections and substrate temperature changes. This paper thus addresses the issue of variability-aware design of the energy-delay optimal linear pipelines that are aimed at operating in both the near-threshold and super-threshold regimes. Precisely, this goal is achieved by deriving the optimal delay line configuration in the soft-edge flip-flops in the near-threshold and the super-threshold operations regimes. The key is to ensure that the same transistor sizes result in effective operation of the delay lines (and hence appropriate settings of the transparency window size) in both operation regimes under the process induced variations. Experimental results demonstrate the efficacy of the proposed solution.

Evaluation of Aircraft Contrails using Dynamic Dispersion Model

Scipedia content — Wed, 03 Feb 2021 21:34:18 +0100

In this paper, an aircraft contrail model developed by researchers at NASA Ames Research Center assuming static atmospheric conditions is extended to simulate the dynamic evolution of contrails triggered by airborne flights. A Lagrangian dispersion model and a cloud microphysics model were added to create the new dynamic contrail model to simulate the physical processes of contrail ice particle formation, growth, advection, and dissipation. The dynamic contrail model can simulate the full life cycle of young-age linear contrails in any day for the entire continental U.S. airspace with real-time meteorological and air traffic data in less than 6 hours. The aircraft-induced contrails weighted by their ages are also calculated to assess the impact at different air traffic control centers.

Approximating the likelihood of historical airline actions to evaluate airline delay cost functions

Scipedia content — Wed, 03 Feb 2021 21:28:16 +0100

Delay cost functions that quantify the cost of delay to airlines are essential to air traffic management research. Seventeen delay cost functions from previous research are evaluated with airline actions in Airspace Flow Programs. Airlines are assumed to solve a minimum cost perfect matching problem when matching flights to slots. Unobserved aspects of airline costs are accounted for by adding a noise term to the cost functions. The goal of this research is to find the cost function and corresponding noise parameters that maximize the likelihood of airline actions during 32 Airspace Flow Programs in the summer of 2006. A heuristic is developed that finds cost noise parameters that maximize an approximation of the log-likelihood of the airline actions. When applied to sample estimation problem instances generated by solving linear programming problems with known noise parameters, the heuristic can more accurately estimate noise parameters than a simple simulation-based approach. Validation efforts based on synthetic airline action data generated with known delay cost functions and noise parameters demonstrate that the heuristic is in many cases able to correctly identify as most likely the delay cost function that was in fact used to generate the synthetic data. However, the heuristic also under-estimates the magnitude of the cost noise variance on these estimation problem instances. Delay costs that are proportional to the length of delay, but with larger proportionality constants for flights bound for hub airports, maximize the approximation of the log-likelihood of the historical airline actions. The estimated standard deviations of the cost noise, expressed as a fraction of the average assignment cost for the historical matchings, ranged from 0.1 to 0.7 for cost functions that achieved relatively large approximate log-likelihoods.

Research on the Layout Optimization of Park and Ride Based on Transport Demand

Scipedia content — Wed, 03 Feb 2021 21:27:08 +0100

With the problem of urban traffic congestion becoming more worse, we are paying more attention on the Park and Ride(P&R), which is one aspect of the Transport Demand Management(TDM). As the study on the layout of P&R is an important part of P&R planning, it plays a major role in strengthening TDM. On the basis of the traffic network system, this paper designs a layout optimization model, taking the total cost of P&R construction and person’s travel as the minimum optimized goal. In the end, this paper also designs a case about it with solving the model by Lingo mathematics software so as to check the effectiveness of the model.

A case study on implementing future human-machine interfaces

Scipedia content — Wed, 03 Feb 2021 21:21:12 +0100

In the scope of the Diesel Reloaded project, we conducted a study on future automotive human-machine interfaces (HMI) with an overview of their relationship to driver assistance systems (DAS). Furthermore, we implemented a series of HMI and DAS concepts in our prototype vehicle and in a modified driving simulator. Emphasis was placed on the following goals: Pushing the complexity away from the driver and inside the intelligent vehicle, developing unified and extendable descriptions of interaction context, defining transitional steps to the long-term goal of user interfaces which augment the driver, leveraging cross-domain technology transfer and addressing relevant societal trends. In this work, we provide a top-level overview of our results and conclusions we drew based upon our two-year research and prototype construction and deployment in the area of human-machine interfaces and driver assistance.

Use of fuzzy optimization and linear goal programming approaches in urban bus lines organization

Scipedia content — Wed, 03 Feb 2021 21:20:12 +0100

Determination of bus stop locations and bus stop frequencies are important issues in public transportation planning. This study analyzes the relationships among demand, travel time, bus stop locations, frequency, fleet size and passenger capacity parameters and develops models for bus stop locations and bus service frequency using fuzzy linear programming and linear goal programming approaches. The models are microscopic and applied to determine the bus stop locations and bus service frequency in the city of Izmir, Turkey, where 26 bus routes pass through two stops in the center city. The fuzzy optimization model minimizes the passenger access time and in-vehicle travel time. The reduction of the values of the bus service frequency and time parameters derived by the two proposed models are validated by a cost function. Encouraging results are obtained. © Springer International Publishing Switzerland 2014.

Auction-type framework for selling inter-domain paths

Scipedia content — Wed, 03 Feb 2021 21:15:04 +0100

In the present Internet, inter-domain routing is based on BGP-4 [1] which selects a single path per destination prefix, thereby preventing carriers and end-users to use the vast inherent path diversity [2]. Addition of multi-path capabilities to the Internet have long been advocated for both robustness and traffic engineering purposes. Some works [3], [4] propose inter-domain multipath architectures. In this paper we consider a new service where carriers offer additional routes to their customers (w.r.t. to BGP default route) as an added-value service. These alternate routes can be used by customers to help them to meet their traffic engineering objectives (better delays etc.) or just for robustness purposes (disjoint alternate routes). Announcing additional paths can lead to scalability issues [5], so one carrier will propagate only the paths that are most interesting for neighboring domains. We propose an auction-like framework adapted to this specific service, allowing one carrier to select the most interesting paths and determine the prices at which these routes can be sold. We consider the case where routes are sold as infinitely duplicable goods (assuming small demands with regards to route capacities). We design a winner determination mechanism, based on the maximization of the seller's revenue, that enforces fair allocation of goods and is loser collusion proof. We also propose a payment mechanism that is proven to be truthful when each bidder submits one (potentially combinatorial) bid.

Analysis and assessment of the electrification of urban road transport based on real-life mobility data

Scipedia content — Wed, 03 Feb 2021 21:14:03 +0100

ng the potential of electric vehicles against actual user needs is a key-issue to integrate individual e-mobility in sustainable transport. An extensive analysis of real-life mobility has been carried out, in view of deriving and quantifying the potential of introducing electric vehicles in urban environment. A large activity data set collected with GPS black boxes mounted on approximately 16,000 vehicles monitored for a one-month period in the Italian province and city of Modena has been purchased and post-processed in order to characterise vehicles’ driving patterns. The ability of different types of electric vehicles to cover the real mobility needs of the users has been then investigated, estimating the percentage of individual trips which might be suitable to be performed by electric vehicles, as well as their potential impact on the electric energy distribution grid depending on different recharging behavioural models. The results show that more than 80% of these trips might be driven electric and that a fleet share lying between 10% and 25% can be immediately converted to battery electric vehicles, being not affected by their limited range. The quantitative key-insights based on real-life mobility data enable to address several issues, ranging from technological aspects, policy impacts and interoperability possibilities offered by the integration of electromobility with the energy distribution grid

Document type: Article

Optimization methods for system track data securing using digital signatures

Scipedia content — Wed, 03 Feb 2021 21:06:50 +0100

Information security is critical in Air Traffic Management systems. Those systems use, among other sources, information received from the Radar Heads Processors. This information is used in the processed form of ASTERIX System Tracks. The accuracy and protection of this data is essential for the Air Traffic Management process. System Track tracks radar data securing by adding a digital signature to each system track. A record requires high processing resources, especially for 2048 bits RSA keys. This approach does not modify the ASTERIX code structure thus keeping the compatibility with other communication partners. However, the use of this method in a sensitive environment like Air Traffic Management may obstruct real time radar data processing. The aim of this paper is to indicate new securing methods that will overcome this problem. Two alternatives are proposed and analyzed that can be combined in order to secure the data in real time. One alternative is using more powerful processing units and the other is applying an optimized method for adding a digital signature to system track data. Unlike the initial approach, where every System Track Record is added a digital signature, the new method relies on adding a digital signature to an entire block of records. The initial method and the optimized method were tested using several processing units. The results showed that the new method adds an insignificant overhead to the existing processing resources allowing the planning for real time system track data securing.

FMCW radar for the sense function of sense and avoid systems onboard UAVs

Scipedia content — Wed, 03 Feb 2021 21:02:40 +0100

Rockwell Collins France (RCF) radar department is currently developing, in close collaboration with TNO in The Hague, The Netherlands, a Frequency Modulated Continuous Wave (FMCW) radar sensor dedicated to Obstacle Warning function and potentially to air traffic detection. The sensor combines flood light illumination and digital beam forming to accommodate demanding detection and coverage requirements. Performances have been evaluated in flight tests and results prove that such a radar sensor is a good candidate for the Sense Function of Sense and Avoid Systems onboard UAV. © 2013 SPIE.

How to manage conflict and ambiguities in localization and map matching

Scipedia content — Wed, 03 Feb 2021 20:58:30 +0100

Since the use of systems of satellite positioning such as the global positioning system (GPS), applications have tried to locate vehicles on maps representing the environment with their attributes. For one decade, this has led to both localization and navigation services for users. Recently, new researches have begun in order to extend the functionalities of the existing systems and thus to develop new applications using these technologies in the design of driver assistance systems. These new systems will indeed allow us to anticipate road departures or prevent overspeed turn approaches. Nevertheless, to deploy such new functionalities, it is imperative to ensure the association of vehicle position with one of the roadmap segments. In this article, we propose a new approach based on the belief theory taking into account the imperfections of available data in order to ensure the positioning and tracking of a vehicle on a roadmap and to manage conflicts and ambiguities using a multi-hypotheses decision.

A traffic congestion problem and solutions: the road between Sawz Square and Shahidan Square in Koya city as a case study

Scipedia content — Wed, 03 Feb 2021 20:53:30 +0100

Re-identification by Inductive Loop Detector: Experimentation on target origin — Destination matrix

Scipedia content — Wed, 03 Feb 2021 20:52:57 +0100

Traffic congestion has led to research on how to use the existing infrastructure more efficiently. The experimental platform SAROT was constructed to allow traffic analysis but also to test new algorithms for traffic modeling and management. Origin-Destination (OD) Matrix is one of the most important traffic information for Intelligent Traffic System. By using the experimental platform SAROT, we want to test algorithms for OD Matrix. To obtain OD matrix, we need to get useful and accurate data by tracking vehicles. Two approaches for tracking vehicles by using Inductive Loop Detector (ILD) are used. Both approaches are computed on real traffic data set and compared. We use threshold decision to improve the correct matching rate for tracking vehicles. We propose a new methodology by associating two algorithms for increasing the correct matching rate. The new methodology was used to perform target OD matrix.

Dynamic speed limit control to resolve shock waves on freeways - Field test results of the SPECIALIST algorithm

Scipedia content — Wed, 03 Feb 2021 20:49:45 +0100

We present the real-world test of the SPECIALIST algorithm in which dynamic speed limits were used to resolve shock waves on freeways. The real-world test was performed in the period September 2009–February 2010 on a 14 km long stretch on the Dutch A12 freeway. For the evaluation of the algorithm various performance measures were determined for each activation of the speed limits. The results show that the SPECIALIST algorithm can resolve shock waves in nearly 80% of the cases when the algorithm activated for shock waves. However, in approximately 50% of the activations the algorithm activated for jam types other than shock waves, in which case the effectivity was 40– 50%. Due to the tuning the stability of the traffic flow could be significantly improved, and the number of average activations per day was increased from 1.5 to 2.9 activations per day. The SPECIALIST algorithm was not only evaluated for traffic performance, but also for the correctness of the algorithm for real traffic in terms of expected qualitative behavior. Although the general operation of the algorithm is according to the theoretical expectations, some points for further improvements are identified during the test.

Adaptive traffic management for secure and efficient emergency services in smart cities

Scipedia content — Wed, 03 Feb 2021 20:44:39 +0100

eer-reviewed Rapid increase in number of vehicles on the roads as well as growing size of cities have led to a plethora of challenges for road traffic management authorities such as traffic congestion, accidents and air pollution. The work presented in this paper focuses on the particular problem of traffic management for emergency services, for which a delay of few minutes may cause human lives risks as well as financial losses. The goal is to reduce the latency of emergency services for vehicles such as ambulances and police cars, with minimum unnecessary disruption to the regular traffic, and preventing potential misuses. To this end, we propose to design a framework in which the Traffic Management System (TMS) may adapt by dynamically adjusting traffic lights, changing related driving policies, recommending behavior change to drivers, and applying essential security controls. The choice of an adaptation depends on the emergency severity level announced by the emergency vehicle(s). The severity level may need to be verified by corresponding authorities to preserve security measures. We discuss the details of our proposed framework and the potential challenges in the paper

Learning-based approach for online lane change intention prediction

Scipedia content — Wed, 03 Feb 2021 20:43:29 +0100

International audience; Predicting driver behavior is a key component for Advanced Driver Assistance Systems (ADAS). In this paper, a novel approach based on Support Vector Machine and Bayesian ﬁltering is proposed for online lane change intention prediction. The approach uses the multiclass probabilistic outputs of the Support Vector Machine as an input to the Bayesian ﬁlter, and the output of the Bayesian ﬁlter is used for the ﬁnal prediction of lane changes. A lane tracker integrated in a passenger vehicle is used for real-world data collection for the purpose of training and testing. Data from different drivers on different highways were used to evaluate the robustness of the approach. The results demonstrate that the proposed approach is able to predict driver intention to change lanes on average 1.3 seconds in advance, with a maximum prediction horizon of 3.29 seconds.

Demonstrating localised workplace travel planning in Limerick City

Scipedia content — Wed, 03 Feb 2021 20:41:17 +0100

eer-reviewed As 'Ireland's Smarter Travel Demonstration City' Limerick is charged with piloting ways to convince its citizens to move around their city in a more sustainable way, in particular to walk, cycle and use public transport more. The Limerick Smarter Travel (LST) project is funded by the Department of Transport with EU support and implemented by a multidisciplinary team of University of Limerick (UL) researchers and Limerick Local Authority staff [Cullinane and Cosgrove 2013]. Travel is an integral part of everyday life, which allows people to meet their needs by providing access to work, services and social gatherings. Commuting to work by car makes up a large proportion of all car traffic, particularly during the morning and evening peak periods in Limerick City. Consequently, workplace travel planning forms an integral part of the LST project. Workplace travel plans are behaviour change packages that are a tried and tested means of achieving mode shift away from the single-occupancy car. In the early 1990s, the idea of workplace travel planning began to gain ground in Britain, based on successful experience in the Netherlands and the US. Research shows that workplace travel plans can reduce car use by between 10-24% [Cairns et al 2004]. However, achieving behaviour change, in relation to travel in particular, and coming to an understanding of how best to achieve it, is an extremely difficult task considering the vast range of factors that can influence behaviour. LST collaborates with the National Transport Authority (NTA) through their already well established Smarter Travel Workplace programme, to implement the LST Workplace and Campus Travel Planning Programme. Limerick’s Local Authority is also involved in both developing their own travel plan, and encouraging other employers to develop their own, site-specific travel plans. Policy makers should consider localised measures to encourage sustainable transport, in particular walking and cycling in urban areas. However, the intrinsic, psychological motivations of car use are not well understood by policy makers. Therefore, non-deliberate choices by motorists make it extremely difficult to influence travel behaviour change. Policy strategies aimed at reducing car use should take these intrinsic motives for car use into account. This paper describes the development and implementation of a comprehensive Workplace and Campus Travel Planning Programme in Limerick City. This paper highlights the importance of integrating transport and planning objectives. This paper describes how the LST project is supporting the development of a travel planning culture by leveraging the planning system at both the level of the Local Authority and the applicant, in order to meet social, environmental and economic objectives for Limerick City.

A Case Based Study for Urban Traffic Control

Scipedia content — Wed, 03 Feb 2021 20:39:52 +0100

Traffic management especially in big cities is a common problem in all over the world. Therefore, traffic management problem on the signals is getting importance and should be solved to save the fuel, time and environment as well. The proposed research is based on the traffic flow and assigns time accordingly. It also provides a way for safe and fast passage for emergency vehicles by sending their information to next signals. The proposed traffic management solution is followed by a case study that reveals the performance and effectiveness of the solution.

Application of image processing to the vehicle license plate recognition

Scipedia content — Wed, 03 Feb 2021 20:24:08 +0100

At present, the traffic engineering and automation have developed, and the vehicle license plate recognition technology need get a corresponding improvement also. In case of identifying a car license picture, the principle of automatic license plate recognition is illustrated in this paper, and the processing is described in detail which includes the pre-processing, the edge extraction, the license plate location, the character segmentation, the character recognition. The program implementing recognition is edited by Matlab. The example result shows that the recognition method is feasible, and it can be put into practice.

Fatigue Analysis of Free Spanning Pipelines Subjected to Vortex Induced Vibrations

Scipedia content — Wed, 03 Feb 2021 20:14:17 +0100

Vortex induced vibration is a major cause of fatigue failure in submarine oil and gas pipelines and steel catenary risers. Even moderate currents can induce vortex shedding, alternately at the top and bottom of the pipeline, at a rate determined by the flow velocity. Each time a vortex sheds, a force is generated in both the in-line and cross-flow direction, causing an oscillatory multi-mode vibration. This vortex induced vibration can give rise to fatigue damage of submarine pipeline spans, especially in the vicinity of the girth welds."/jats:p" "jats:p"In this paper, an integrated numerical framework is presented to predict and identify free spans that may be vulnerable to fatigue damage caused by vortex induced vibrations (VIV). An elegant and efficient algorithm is introduced to simulate offshore pipeline installation on an uneven seabed. Once the laydown simulation has been completed, the free spans can be automatically detected. When the fatigue screening for both inline and cross-flow VIV indicates that a particular span may be prone to vortex induced vibrations, a detailed fatigue analysis is required."/jats:p" "jats:p"Amplitude response models are constructed to predict the maximum steady state VIV amplitudes for a given pipeline configuration (mechanical properties) and sea state (hydrodynamic parameters). The vibration amplitudes are translated into corresponding stress ranges, which then provide an input for the fatigue analysis. A case study from the offshore industry is presented, and sensitivity analyses are performed to study the influence of the seabed conditions, where special emphasis is devoted on the selection of pipe soil interaction parameters.

Air traffic controller usage of terminal-area speed advisories

Scipedia content — Wed, 03 Feb 2021 20:08:06 +0100

• Problem — Uninterrupted Optimized Profile Descents (OPDs) limited to periods of low demand

High-resolution multibeam sonar for subsea leakage detection

Scipedia content — Wed, 03 Feb 2021 20:06:55 +0100

This paper concerns detection of subsea leaks in offshore oil and gas installations by application of Multi Beam Echo Sounder (MBES) technology. Offshore recovery of hydrocarbon is carried out in still deeper waters, and in increasingly environmental vulnerable areas such as the arctic regions. Subsea leaks can occur from process infrastructure and pipelines or it can occur from the seabed itself, where reservoir instability may result in leaks. Recent catastrophic accidents within the offshore industry have lead to an increased need for monitoring subsea installations. Here, leak detection performance of the 400 kHz high resolution sonar, the Seabat 7128 forward looker, is presented. Data from an actual leaks are presented. It is shown how the sonar discovers a huge leak from a subsea reservoir. Other examples are based on small synthetic leaks established in harbors and near coastal areas. Here, detection performance is evaluated in terms of fluid leaks with varying pressure difference, orifice diameter, and range. The algorithm associated with small leaks can detect and localize a weak 5 bar fresh water flow originating from an 1 mm orifice at a distance of 75 meter. The results are followed up by a discussion on limitations and opportunities.

Towards Application of Automated Planning in Urban Traffic Control

Scipedia content — Wed, 03 Feb 2021 19:53:06 +0100

dvanced urban traffic control systems are often based on feed-back algorithms. For instance, current traffic control systems often operate on the basis of adaptive green phases and flexible co-ordination in road (sub) networks based on measured traffic conditions. However, these approaches are still not very efficient during unforeseen situations such as road incidents when changes in traffic are requested in a short time interval. Therefore, we need self-managing systems that can plan and act effectively in order to restore an unexpected road traffic situations into the normal order. A significant step towards this is exploiting Automated Planning techniques which can reason about unforeseen situations in the road network and come up with plans (sequences of actions) achieving a desired traffic situation. In this paper, we introduce the problem of self-management of a road traffic network as a temporal planning problem in order to effectively navigate cars throughout a road network. We demonstrate the feasibility of such a concept and discuss our preliminary evaluation in order to identify strengths and weaknesses of our approach and point to some promising directions of future research.

Urban and social sensing for sustainable mobility in smart cities

Scipedia content — Wed, 03 Feb 2021 19:47:59 +0100

In this contribution, we describe the SMARTY project. The project is funded by the Tuscany Region and aims to develop innovative services for sustainable transport and mobility in smart cities. These services are based on data collected by environmental and social sensors: such data are pre-processed and analysed by data mining techniques for determining useful information such as state of the traffic flow and parking lots, special events, demonstrations and accidents. All this information is used by SMARTY to suggest optimal routes to the users, taking also the multi-modality into account.

Levelling of heating and vehicle demand in distribution networks using randomised device control

Scipedia content — Wed, 03 Feb 2021 19:46:25 +0100

Rising demand from electrical heating and vehicles will drive major distribution network reinforcement costs unless 24-hour demand profiles can be levelled. We propose a demand response scheme in which the electricity supplier provides a signal to a “smart home” control unit that manages the consumer’s appliances using a novel approach for reconciliation of the consumer’s needs and desires with the incentives supplied by the signal. The control unit allocates demand randomly in timeslots that are acceptable to the consumer but with a probability biased in accordance with the signal provided by the supplier. This behaviour ensures that demand response is predictable and stable and allows demand to be shaped in a way that can satisfy distribution network constraints.

Vehicle Safety Evaluation based on Driver Drowsiness and Distracted and Impaired Driving Performance Using Evidence Theory

Scipedia content — Wed, 03 Feb 2021 19:41:40 +0100

Vehicle safety is the study and practice for min- imizing the occurrences and consequences of traffic accidents. It is found that driver behaviors such as drowsiness, impaired driving and distraction are contributing factors to traffic acci- dents. In complex road surroundings, comprehensive analysis is more robust than separate evaluations which are broadly proceeded with. In this paper, we propose a vision-based nonintrusive system involving lane and driver's eye features to analyze driver behaviors. In the framework of evidence theory, evaluations of driver drowsiness and distracted and impaired driving performance are integrated to evaluate vehicle safety in real time. The system was validated in real world scenarios, and experimental results demonstrate that it is promising to improve the robustness and temporal response of vehicle safety vigilance.

MOP, MAOP, DP and MAWP: Understanding the Differences to Avoid Unnecessary Costs

Scipedia content — Wed, 03 Feb 2021 19:40:12 +0100

The ASME pressure vessel and piping codes and standards provide excellent references for code writers in international jurisdictions when developing their own national codes and for safety authorities when developing regulatory acts. The inclination to customize this effort may add unnecessary complexity that unintentionally obscures the underlying engineering principles."/jats:p" "jats:p"In developing the Canadian pipeline code, the authors use the notion of maximum operating pressure or MOP similar to the MOP found in the ASME codes for pipelines. While the ASME code definitions are explicit and articulate, the MOP defined in the Canadian code is less so and has led to inadvertent confusion by industry users. Misunderstanding of complementary terminology used in ancillary ASME standards has contributed to further complexities. The use of the term, maximum allowable operating pressure or, MAOP in the ASME pipeline codes has further reduced clarity when integrating this term into international codes and regulatory acts."/jats:p" "jats:p"This paper examines, in detail, some aspects of the Canadian pipeline code and illustrates via a representative case study some of the aforementioned difficulties that have arisen. These difficulties resulted in unnecessary derating of assets by imposing operational limits that were well below actual capacity. A clear explanation of the engineering principles underlying the provisions for codes which use a “design by rules” philosophy will help operators set appropriate limits for both static and dynamic loads that may not be apparent in the specific codes considered and will be expository for regulators and code users in general.

Activity based scheduling simulator for product transport using pipeline networks

Scipedia content — Wed, 03 Feb 2021 19:39:59 +0100

Oil companies often rely on scheduling algorithms to increase the throughput of oil derivatives and other products which are transported through pipeline networks. This work presents an architecture for a scheduling simulator for pipeline networks, and outlines the rules for a method that is used in that simulation. Its core was developed as part of a decision support system that assists its users to face a very difficult challenge: how to operate a large pipeline network in order to adequately transport products from refineries to local markets. We describe the problem that led to the development of that methodology, the model and architecture of the simulator, in addition to elaborating further on the methodology which is the simulator cornerstone. Finally, a simulation example is presented as well as the results of this research.

Parking Pricing for a Sustainable Transport System

Scipedia content — Wed, 03 Feb 2021 19:37:28 +0100

The purpose of this study has been the develop of a model for designing an efficient parking pricing policy. The aim is an intelligent control and management system of parking pricing integrated with a redefinition of the circulation scheme for a limited traffic zone in the Central Business District (CBD) of Palermo. The transport demand over the entire area of the town has been studied in order to design various parking pricing scenarios with the application of an additional cost on parking inside the selected area of the CBD. This area attracts most of the private vehicular traffic and it is characterized by university faculties, schools, hospitals, offices and commercial areas. The optimal hourly toll is defined by an iterative maximization process of an objective function. This objective function is subject to the following constraint: the percentage of available parking in the various parking zones has to remain major of the 30%. In this way, the users who need to park close to their final destination can easily find parking. Otherwise it is possible to leave the private car in a “park and ride” area and taking a shuttle bus directed towards the zones of the CBD. A basic principle of this pricing policy is the re-use of revenues for two purposes: to design a shuttle bus service that connects the various “park and ride” areas to the CBD and to improve the local public transport service on the OD pairs that show high travel demand. At the same time it is necessary to eliminate the stop and go flow in cordon roads to increase the capacity and avoid congestion in these critical links. The method shows that in a very simple, and relatively fast, way is possible to get a proposal for the modification of the parking pricing scheme that makes the city center no longer stifled by private car traffic.

Statistical Method Tools to Analyze Ageing Effects on Li-Ion Battery Performances

Scipedia content — Wed, 03 Feb 2021 19:28:12 +0100

International audience; This paper describes the analysis of recorded data parameters from electrical battery ageing during electric vehicle use. These data allow traditional battery ageing investigation based on resulting capacity fade and resistance raise. The measured variables are examined in order to explain the battery ageing obtained during the experiment. Such study enables us to identify the main ageing factors. Then, detailed statistical dependency explorations present results on battery ageing phenomena. All studies are done on real data collected from Lithium-ion battery; thereby results demonstrate and quantify a relationship between variables and battery ageing mechanisms.

Flights in my hands : coherence concerns in designing Strip'TIC, a tangible space for air traffic controllers

Scipedia content — Wed, 03 Feb 2021 19:15:20 +0100

Best Paper Honorable Mention award; International audience; We reflect upon the design of a paper-based tangible interactive space to support air traffic control. We have observed, studied, prototyped and discussed with controllers a new mixed interaction system based on Anoto, video projection, and tracking. Starting from the understanding of the benefits of tangible paper strips, our goal is to study how mixed physical and virtual augmented data can support the controllers' mental work. The context of the activity led us to depart from models that are proposed in tangible interfaces research where coherence is based on how physical objects are representative of virtual objects. We propose a new account of coherence in a mixed interaction system that integrates externalization mechanisms. We found that physical objects play two roles: they act both as representation of mental objects and as tangible artifacts for interacting with augmented features. We observed that virtual objects represent physical ones, and not the reverse, and, being virtual representations of physical objects, should seamlessly converge with the cognitive role of the physical object. Finally, we show how coherence is achieved by providing a seamless interactive space.

A prospective exercise to develop a common vision to support MSP? An experimentation in France

Scipedia content — Wed, 03 Feb 2021 19:14:03 +0100

International audience

Classical modernist planning and the menace of automobile dependence in cities: the case of Abuja, Nigeria

Scipedia content — Wed, 03 Feb 2021 19:01:52 +0100

Unequivocally, it has become increasingly clear that the approach of Classical Modernist planning (CMP) that prevailed after World War II emphasizes huge permissivity for low-density sprawling suburban development and the meteoric rise of motorization in cities. The implicit “predict and provide” approach of building and expansion of roads to ease congestion continued to skew investments on transportation towards permitting private automobile ownership and use at the expense of public transportation. As a result, the inherent menaces of automobile dependence are continuing in cities especially in the Global South including Abuja, Nigeria. This study has illustrated that the prevailing CMP system in Abuja, has continually spurred and fuelled the growth of suburbia. Consequently, the emerging automobile dependent mobility pattern is indeed plagued with the challenges of CO2 emissions, traffic congestion, and related man-hour and fuel wastage. This study reveals that by institutionalizing spatial planning strategies, such as bus rapit transit (BRT), transit oriented development (TOD) and congestion pricing, it is possible to transform sprawling automobile dependent cities to smart compact transit dependent cities. Hence, the implicit CO2 emissions and traffic congestion challenges of man-hour and fuel wastage on the AYA route in Abuja are retrofitted, and the ecological and carbon footprints are dwarfed.

Safe Overclocking of Tightly Coupled CGRAs and Processor Arrays using Razor

Scipedia content — Wed, 03 Feb 2021 19:01:15 +0100

Overclocking a CPU is a common practice among home-built PC enthusiasts where the CPU is operated at a higher frequency than its speed rating. This practice is unsafe because timing errors cannot be detected by modern CPUs and they can be practically undetectable by the end user. Using a timing speculation technique such as Razor, it is possible to detect timing errors in CPUs. To date, Razor has been shown to correct only unidirectional, feed-forward processor pipelines. In this paper, we safely overclock 2D arrays by extending Razor correction to cover bidirectional communication in a tightly coupled or lockstep fashion. To recover from an error, stall wavefronts are produced which propagate across the device. Multiple errors may arise in close proximity in time and space; if the corresponding stall wavefronts collide, they merge to produce a single unified wavefront, allowing recovery from multiple errors with one stall cycle. We demonstrate the correctness and viability of our approach by constructing a proof-of-concept prototype which runs on a traditional Altera FPGA. Our approach can be applied to custom computing arrays, systolic arrays, CGRAs, and also time-multiplexed FPGAs such as those produced by Tabula. As a result, these devices can be overclocked and safely tolerate dynamic, data-dependent timing errors. Alternatively, instead of overclocking, this same technique can be used to `undervolt' the power supply and save energy.

Physical modelling to minimise air entrainment over an industrial weir and into a discharge pipeline

Scipedia content — Wed, 03 Feb 2021 19:00:28 +0100

Physical modelling was used to simulate cooling water flow entering a chamber over an industrial weir and exiting through long discharge pipelines. The weir was required to maintain a backwater for condensers, but also resulted in significant aeration of the flow. The objectives were to minimise the air entrained to the discharge pipeline and to ensure de-aeration of any air within the pipeline was fully effective. Physical modelling was selected as the most reliable means of investigation as the complex air entrainment and free surface interactions would require highly complex CFD numerical modelling, with limited confidence in the results. The physical modelling study concentrated on flow patterns, air entrainment and the amount of air released within the chamber, discharge pipes and air release structures. A suite of flow and entrainment characterisations by dimensionless numbers have been assembled from the literature and used to scale the model of this complex system. The study highlights the need for careful consideration of geometry to minimise aeration and how relatively simple changes to flow asymmetry can reduce the air entrainment. The solution is relevant to other entrainment problems.

Constrained Dynamic Control of Traffic Junctions

Scipedia content — Wed, 03 Feb 2021 18:56:50 +0100

Excessive traffic in our urban environments has detrimental effects on our health, economy and standard of living. To mitigate this problem, an adaptive traffic lights signalling scheme is developed and tested in this paper. This scheme is based on a state space representation of traffic dynamics, controlled via a dynamic programme. To minimise implementation costs, only one loop detector is assumed at each link. The comparative advantages of the proposed system over optimal fixed time control are highlighted through an example. Results will demonstrate the flexibility of the system when applied to different junctions. Monte Carlo runs of the developed scheme highlight the consistency and repeatability of these results.

peer-reviewed

Optimizing the Electric Charge Station Network of EŞARJ

Scipedia content — Wed, 03 Feb 2021 18:55:57 +0100

2nd International Conference on Information Technology and Quantitative Management (ITQM) -- JUN 03-05, 2014 -- Natl Res Univ, Higher Sch Econ, Moscow, RUSSIA

WOS: 000360713800002

In this study, we adopt the classic capacitated p-median location model for the solution of a network design problem, in the domain of electric charge station network design, for a leading company in Turkey. Our model encompasses the location preferences of the company managers as preference scores incorporated into the objective function. Our model also incorporates the capacity concerns of the managers through constraints on maximum number of districts and maximum population that can be served from a location. The model optimally selects the new station locations and the visualization of model results provides additional insights. (C) 2014 Published by Elsevier B.V.

Int Acad Informat Technol & Quantitat Management, Yandex LLC, Chinese Acad Sci, Res Ctr Fictitious Econ & Data Sci, Univ Nebraska Omaha, Global Act Inc, CurrexSole

Challenges and Opportunities in Taxi Fleet Anomaly Detection

Scipedia content — Wed, 03 Feb 2021 18:52:05 +0100

To enhance fleet operation and management, logistics companies instrument their vehicles with GPS receivers and network connectivity to servers. Mobility traces from such large fleets provide significant information on commuter travel patterns, traffic congestion and road anomalies, and hence several researchers have mined such datasets to gain useful urban insights. These logistics companies, however, incur significant cost in deploying and maintaining their vast network of instrumented vehicles. Thus research problems, that are not only of interest to urban planners, but to the logistics companies themselves are important to attract and engage these companies for collaborative data analysis. In this paper, we show how GPS traces from taxis can be used to answer three different questions that are of great interest to a taxi operator. These questions are 1) What is the occupancy rate of the taxi fleet?, 2) What is the effect of route selection on the distance and time of a chosen route?, and 3) Does an analysis of travel times show deviations from the posted speed limits? We provide answers to each of these questions using a 2 month dataset of taxi records collected from over 10,000 taxis located in Singapore. The goal of this paper is to stimulate interest in the questions listed above (as they are of high interest to fleet operators) while also soliciting suggestions for better techniques to solve the problems stated above.

Optimal control of airport operations with gate capacity constraints

Scipedia content — Wed, 03 Feb 2021 18:50:06 +0100

The mitigation of airport surface congestion is an important step towards increasing the efficiency of the air transportation system, and decreasing flight delays. This paper proposes a strategy to control the release of departing flights from their gates with the specific objective of reducing their taxi times and fuel consumption, while limiting the impact on airport throughput. The proposed strategy also explicitly accounts for the practical constraints that arise due to limited gate resources at the airport. A stochastic network abstraction of the airport surface is used to model aircraft movement, and the optimal release time for each aircraft is calculated using dynamic programming. Simulations of operations at Boston's Logan International Airport in the US are used to illustrate the effects of the resultant policies.

National Science Foundation (U.S.) (CAREER Award ECCS-0745237)

National Science Foundation (U.S.) (Cyber-Physical Systems Award 0931843)

Document type: Conference object

An Algebraic Observer for Leak Detection and Isolation in Plastic Pipelines

Scipedia content — Wed, 03 Feb 2021 18:49:29 +0100

International audience; In the continuation of authors' studies on leak diagnosis in pipelines, a new model-based Leak Detection and Isolation (LDI) algorithm is designed. This system only uses measures of flow and pressure coming from sensors placed at the ends of a pipeline. The present approach is based on a finite nonlinear pipeline model, and extended with variables related to the leak. On this basis, the purpose here is to investigate the use of a so-called algebraic observer to estimate the leak position and its magnitude. The corresponding observer design is thus presented, and its performances are illustrated both with simulation results, and experimental ones, with data taken from a real pipeline prototype.

An assessment of the National Transport Master Plan (NATMAP) 2050 for South Africa and its implementation framework

Scipedia content — Wed, 03 Feb 2021 18:47:59 +0100

NATMAP (2050) was approved by the South African Government in 2011. The focus of the project is to ensure that by 2050 transportation development will meet the needs of freight and passenger customers; to ensure accessible, affordable, safe, frequent, high quality, reliable, efficient and seamless transport operations and infrastructure provision and development. The project makes provision for a process of continued upgrading, innovative, flexible, economically and environmentally sustainable transportation that will support and enable government strategies, growth, development, redistribution, employment and social integration within the national spatial system. The project endeavours to address this distorted land use and transportation situation provincially and nationally. The research methodology includes an assessment of the Action Agenda as included in the NATMAP (2050) source documents and its supporting methodologies and strategic approaches. The research results are reported on from a sustainable transportation and strategic perspective. It will include an in depth analysis of the strategies formulated, prioritization model, implementation projects and strategic development programme. The improvement of special intervention transportation development focuses is included as to enhance sustainable transport development within all spatial systems.

Stereoscopic displays for air traffic control: conflict judgement performance as a function of visualisation, task characteristics and expertise

Scipedia content — Wed, 03 Feb 2021 18:47:24 +0100

Three different stereoscopic 3D visualisations are compared with the 2D display currently used at air traffic control (ATC) controller working positions. Using safety critical air traffic scenarios, air traffic controllers (ATCOs), pilots, and two groups of laypersons, one of which with appropriate training, are asked to judge safety critical scenarios showing two converging aircraft. To simulate the cognitive demands ATCOs have to face when required to process both visual information of the traffic situation display and auditory information caused by incoming radio messages at the same time, an auditory task is added. Due to the experimental manipulation of visualisation-, task-, and person-related variables, the results allow for an explanation of the inconsistent results that have been reported in studies evaluating the use of 3D for ATC. Analyses reveal that performance differences between 2D and 3D depend on both task characteristics and the level of expertise. While the judgement certainty of 2D and 3D is virtually equal in all cases of conflict, the observed differences between the modes of visualisation appear to be due to the dimension on which the aircraft miss each other in case of separation. When judgement certainty is ignored, no noteworthy differences appear. Thus, the results depend on the individual response criterion, because it represents the level of uncertainty the operator is willing to accept.

Impact of gate assignment on gate-holding departure control strategies

Scipedia content — Wed, 03 Feb 2021 18:43:49 +0100

Gate holding reduces congestion by reducing the number of aircraft present on the airport surface at any time, while not starving the runway. Because some departing flights are held at gates, there is a possibility that arriving flights cannot access the gates and have to wait until the gates are cleared. This is called a gate conflict. Robust gate assignment is an assignment that minimizes gate conflicts by assigning gates to aircraft to maximize the time gap between two consecutive flights at the same gate; it makes gate assignment robust, but passengers may walk longer to transfer flights. In order to simulate the airport departure process, a queuing model is introduced. The model is calibrated and validated with actual data from New York La Guardia Airport (LGA) and a U.S. hub airport. Then, the model simulates the airport departure process with the current gate assignment and a robust gate assignment to assess the impact of gate assignment on gate-holding departure control. The results show that the robust gate assignment reduces the number of gate conflicts caused by gate holding compared to the current gate assignment. Therefore, robust gate assignment can be combined with gate-holding departure control to improve operations at congested airports with limited gate resources.

Comment: Submitted to IEEE Transactions on Intelligent Transportation System

Video sharing propagation in social networks: Measurement, modeling, and analysis

Scipedia content — Wed, 03 Feb 2021 18:31:45 +0100

The social networking services (SNS) have drastically changed the information distribution landscape and people's daily life. With the development in broadband accesses, video has become one of the most important types of objects spreading among social networking service users, yet presents more significant challenges than other types of objects, not only to the SNS management, but also to the network traffic engineering. In this paper, we take an important step towards understanding the characteristics of video sharing propagation in SNS, based on the real viewing event traces from a popular SNS in China. We further extend the epidemic models to accommodate the diversity of the propagation, and our model effectively captures the propagation process of video sharing in SNS.