Scipedia: Documents published in 2010

A high speed tri-vision system for automotive applications

Scipedia content — Mon, 22 Mar 2021 22:47:23 +0100

Cameras are excellent ways of non-invasively monitoring the interior and exterior of vehicles. In particular, high speed stereovision and multivision systems are important for transport applications such as driver eye tracking or collision avoidance. This paper addresses the synchronisation problem which arises when multivision camera systems are used to capture the high speed motion common in such applications. An experimental, high-speed tri-vision camera system intended for real-time driver eye-blink and saccade measurement was designed, developed, implemented and tested using prototype, ultra-high dynamic range, automotive-grade image sensors specifically developed by E2V (formerly Atmel) Grenoble SA as part of the European FP6 project �C sensation (advanced sensor development for attention stress, vigilance and sleep/wakefulness monitoring). The developed system can sustain frame rates of 59.8?Hz at the full stereovision resolution of 1280?��?480 but this can reach 750?Hz when a 10?k pixel Region of Interest (ROI) is used, with a maximum global shutter speed of 1/48000?s and a shutter efficiency of 99.7%. The data can be reliably transmitted uncompressed over standard copper Camera-Link? cables over 5 metres. The synchronisation error between the left and right stereo images is less than 100?ps and this has been verified both electrically and optically. Synchronisation is automatically established at boot-up and maintained during resolution changes. A third camera in the set can be configured independently. The dynamic range of the 10bit sensors exceeds 123?dB with a spectral sensitivity extending well into the infra-red range. The system was subjected to a comprehensive testing protocol, which confirms that the salient requirements for the driver monitoring application are adequately met and in some respects, exceeded. The synchronisation technique presented may also benefit several other automotive stereovision applications including near and far-field obstacle detection and collision avoidance, road condition monitoring and others.

Document type: Article

Wildlife Strike Risk Assessment in Several Italian Airports: Lessons from BRI and a New Methodology Implementation

Scipedia content — Mon, 22 Mar 2021 20:42:13 +0100

The presence of wildlife in airport areas poses substantial hazards to aviation. Wildlife aircraft collisions (hereafter wildlife strikes) cause losses in terms of human lives and direct monetary losses for the aviation industry. In recent years, wildlife strikes have increased in parallel with air traffic increase and species habituation to anthropic areas. In this paper, we used an ecological approach to wildlife strike risk assessment to eight Italian international airports. The main achievement is a site-specific analysis that avoids flattening wildlife strike events on a large scale while maintaining comparable airport risk assessments. This second version of the Birdstrike Risk Index (BRI2) is a sensitive tool that provides different time scale results allowing appropriate management planning. The methodology applied has been developed in accordance with the Italian Civil Aviation Authority, which recognizes it as a national standard implemented in the advisory circular ENAC APT-01B.

Document type: Article

The impact of a congestion assistant on traffic flow efficiency and safety in congested traffic caused by a lane drop

Scipedia content — Tue, 16 Feb 2021 13:14:58 +0100

This article presents the results of a microscopic traffic simulation study conducted to investigate the impact of a Congestion Assistant on traffic efficiency and traffic safety. The Congestion Assistant is an in-vehicle system in which an active pedal supports the driver when approaching congestion and a stop-and-go function when driving in congestion. The authors used an Intelligent Transportation System (ITS) Modeller traffic flow simulation tool to study the effect of the Congestion Assistantin congestion caused by a lane drop. This article describes (a) how the Congestion Assistant operates and (b) the main features of the ITS Modeller. Furthermore, it examines the calibration and validation of the ITS Modeller for congestion caused by a lane drop using traffic flow measurements on a segment of the Dutch A12 highway. Simulation experiments of different penetration rates and system settings show that the stop and go leads to a 30% decrease in travel-time delay at a 10% penetration rate, while the active pedal leads to small reductions in travel-time delay. Compared with the stop-and-go function, the active pedal has fewer sharp accelerations and decelerations, which implies better traffic safety and driver comfort. The effect of the stop-and-go active pedal combination is similar to that of the stop-and-go function on its own. The authors further discuss the implications of the results.

The environmental impact and risk assessment of CO2 capture, transport and storage - an evaluation of the knowledge base using the DPSIR framework

Scipedia content — Tue, 16 Feb 2021 13:09:59 +0100

In this paper we identify and characterize known and new environmental consequences associated with CO2 capture from power plants, transport by pipeline and storage in geological formations (CCS). The DPSIR framework, describing environmental Drivers, Pressures, States, Impacts and Responses, is used to systematically review environmental impact assessment procedures and scientific literature on CCS. Also, it is investigated whether crucial knowledge on environmental impacts is lacking that may postpone the implementation of CCS projects. The findings of this study are that the capture of CO2 from power plants results in a change in the environmental profile of the power plant. This change encompasses trade-offs and synergies in the reduction of key atmospheric emissions, being: NOx, SO2, NH3, particulate matter, Hg, HF and HCl. The largest trade-offs are found for the emission of NOx and NH3 when equipping power plants with post-combustion capture. Synergy is expected for SO2 emissions, which are low for all power plants with CO2 capture. An increase in water consumption ranging between 32% and 93% and an increase in waste and by-product creation with tens of kilotonnes annually is expected for a large-scale power plant (1?GWe), but exact flows and composition are uncertain. The cross-media effects of CO2 capture are found to be uncertain and not quantified. For the assessment of the safety of CO2 transport by pipeline at high pressure an important knowledge gap is the absence of validated release and dispersion models for CO2 releases due to pipeline failures. There is also uncertainty in estimating the failure rates for CO2 pipelines. Furthermore, uniform CO2 exposure thresholds, detailed dose-response models and specific CO2 pipeline regulation are absent. Most gaps in environmental information regarding the CCS chain are identified and characterized for the risk assessment of the underground, non-engineered, part of the storage activity. This uncertainty is considered to be larger for aquifers than for hydrocarbon reservoirs. Failure rates are found to be heavily based on expert opinions and the doseresponse models for ecosystems or target species are not yet developed. Integration and validation of various sub-models describing fate and transport of CO2 in various compartments of the geosphere is at an infant stage. Concluding, it is not possible to execute a quantitative risk assessment for the non-engineered part of the storage activity with high confidence. Finally, several recommendations have been formulated to deal with the knowledge gaps identified in this study.

A visual display enhancing comfort by counteracting airsickness

Scipedia content — Tue, 16 Feb 2021 12:57:54 +0100

simulator study has been conducted demonstrating a positive effect on airsickness by utilizing a 3D artificial Earth-fixed visual pattern. Participants were exposed to the same turbulent physical aircraft motion in a simulator three times in a row, each time using a different visual cue. In one condition only the interior of the simulator cabin was visible. In another condition an Earth-fixed star field moving opposite the simulator cabin was projected in front of the participant. In a third condition the same star field was used, however with additional anticipatory information by means of a rollercoaster like track showing the trajectory to go. Participants were asked for their misery and joyfulness ratings at fixed time instants using an 11-points misery scale (no problems-vomiting) and joyfulness scale (unpleasant-pleasant). The results showed that viewing an Earth-fixed visual frame moving instantaneously opposite the cabin motion did reduce motion sickness significantly by a factor of 1.6, thereby improving comfort. This condition could be applied in air transport, where often a monitor is available in the back of the seat ahead. The largest effect, i.e., a reduction by a factor of 4.2 was realized by adding anticipatory information. Although it is not possible to predict the effect of turbulence on the aircraft motion yet, an anticipatory display might already be applicable in other domains, such as at sea by using a wave radar and a ship motion model. ? 2011 Elsevier B.V. All rights reserved.

The City Logistics within the Transformation Process of East Naples

Scipedia content — Tue, 16 Feb 2021 12:56:20 +0100

Stoccaggio e trasporto merci hanno assunto, già da alcuni anni, un ruolo rilevante nell’area orientale di Napoli, con impatti significativi sulla qualità urbana ed ambientale dell’area. In quest’area, anche grazie alla sua vicinanza ai principali nodi della mobilità (porto, aeroporto, stazione ferroviaria) e alla significativa presenza di aree produttive dismesse o in dismissione, trovano oggi spazio numerose attività di stoccaggio e spedizione merci, in molti casi localizzate all’interno di ex aree industriali, in assenza di una reale ottica “sistemica”. Pertanto, a partire da una breve disamina dell’evoluzione dell’area orientale e di quanto previsto dagli strumenti urbanistici vigenti per la sua trasformazione, il contributo focalizza l’attenzione sul ruolo attuale dslle attività di stoccaggio e trasporto merci nell’area. Quindi, sulla base di alcune recenti esperienze di italiane e in riferimento ad ipotesi già avanzate per l’organizzazione di una piattaforma logistica nell’area orientale di Napoli -quale strumento per ottimizzare le necessità di stoccaggio e trasporto merci riducendone le esternalità negative- valuta la compatibilità di tali scelte con le prospettive di evoluzione/trasformazione dell’area e il potenziale ruolo che l’area potrebbe svolgere in una prospettiva di ri-organizzazione del trasporto merci in ambito urbano.

Optimization of Link Load Balancing in Multiple Spanning Tree Routing Networks

Scipedia content — Tue, 16 Feb 2021 12:55:44 +0100

In telecommunication networks based on the current Ethernet technology, routing of traffic demands is based on multiple spanning trees: the network operator configures different routing spanning trees and assigns each demand to be routed in one of the selected spanning trees. A major optimization issue in this solution is the combined determination of (i) a set of appropriate spanning trees, and (ii) assignment of demands to the trees, in order to achieve an optimal load balancing on the links of the network. In this paper we consider models and solving techniques for lexicographical optimization of two load balancing objective functions. The first objective is the min-max optimization of the n worst link loads (with n up to the total number of network links), and the second objective is the minimization of the average link load (when n is smaller than the total number of network links). Besides exact methods, a heuristic technique that can compute both feasible solutions and lower bounds for the addressed optimization problem is proposed. Finally, we discuss effectiveness of different solution using results of a numerical study of realistic case studies. The authors wish to thank Michal Zagozdzon for the fruitful discussions on the adaptation of the max-min fairness solution methods to the problems addressed in this paper. This work has been done under the Joint Specific Project METRO-ETHERNET within the FP7 Network of Excellence "Euro NF". The Portuguese coauthors have been partially funded by FCT (Fundacao para a Ciencia e a Tecnologia) through project PTDC/EIA/64772/2006 and through the post-doc grant SFRH/BPD/41581/2007 of D. Santos. The co-authors from Warsaw University of Technology have been partially funded by the Polish Ministry of Science and Higher Education (MNiSW, grant no. N517 397334 "Optimization Models for NGI Core Networks"). M. Pioro has been also supported by the Swedish Research Council (Vetenskapsradet, grant no. 621-2006-5509 "Modeling and Design of Core Internet Networks").

Connect & Drive: design and evaluation of cooperative adaptive cruise control

Scipedia content — Tue, 16 Feb 2021 12:54:32 +0100

On the Effectiveness of an Opportunistic Traffic Management System for Vehicular Networks

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

Road congestion results in a huge waste of time and productivity for millions of people. A possible way to deal with this problem is to have transportation authorities distribute traffic information to drivers, which, in turn, can decide (or be aided by a navigator) to route around congested areas. Such traffic information can be gathered by relying on static sensors placed at specific road locations (e.g., induction loops and video cameras) or by having single vehicles report their location, speed, and travel time. While the former approach has been widely exploited, the latter has come about only more recently; consequently, its potential is less understood. For this reason, in this paper, we study a realistic test case that allows the evaluation of the effectiveness of such a solution. As part of this process, (a) we designed a system that allows vehicles to crowd-source traffic information in an ad hoc manner, allowing them to dynamically reroute based on individually collected traffic information; (b) we implemented a realistic network-mobility simulator that allowed us to evaluate such a model; and (c) we performed a case study that evaluates whether such a decentralized system can help drivers to minimize trip times, which is the main focus of this paper. This study is based on traffic survey data from Portland, OR, and our results indicate that such navigation systems can indeed greatly improve traffic flow. Finally, to test the feasibility of our approach, we implemented our system and ran some real experiments at UCLA's C-Vet test bed.

Estimation of the acute inhalation hazards of chemicals based on route-to-route and local endpoint extrapolation: Experience from Bulk Maritime Transport

Scipedia content — Tue, 16 Feb 2021 12:45:01 +0100

Data on acute lethal inhalation toxicity from animal studies are commonly required for assessing the hazards to human health of volatile, gaseous and dusty chemicals or their mixtures. The International Maritime Organisation (IMO) made the provision of acute inhalation toxicity data a mandatory requirement for the carriage of bulk liquid chemicals transported by sea in tank ships, thereby creating the need for inhalation data on many hundreds of chemicals in bulk maritime transport. Taking note of previously published proposals for estimating acute inhalation toxicity hazards for chemicals, and the paucity of measured experimental data, an extrapolation method has been developed by the Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) to partly fulfil this need. This method should be seen as a pragmatic approach to the challenge of missing measured experimental test data, with the added benefit of reducing tests in experimental animals. The method is based on a route-to-route (i.e. between-route) extrapolation of information on acute oral and/or dermal toxicity, in combination with data on the potential for irritation and/or corrosion to skin and eyes. The validation of this method was based on the individual evaluation of inhalation toxicity studies for 330 chemicals, including mixtures and many important chemical groups, for which the IMO holds public and industry-confidential data. The authors contend that this extrapolation method offers a reliable basis for hazard evaluation in the context of bulk maritime transport, and the 'GESAMP inhalation toxicity extrapolation method' has become part of the IMO regulatory system for the carriage of bulk liquids (i.e. noxious liquid substances) on board tank ships.

Results of field trials with dynamic speed limits in the Netherlands: Improving throughput and safety on the A12 freeway

Scipedia content — Tue, 16 Feb 2021 12:34:09 +0100

In the past few years, field trials with dynamic speed limits have been carried out on the Dutch freeway network. This paper discusses the tests at one of the field trial locations. On this location two test were carried out; the speed limit was lowered when there were congestion problems and during heavy rain. The field trial lasted for six months. Two new algorithms were developed to determine when the speed limit should be changed: an algorithm that uses real-time precipitation radar data to advise appropriate speed limits during heavy rain, and the SPECIALIST algorithm for resolving shockwaves. The field trials were evaluated using loop detector data as well as camera data. Changes in driver behavior, traffic flow characteristics, traffic safety, air quality and noise levels were analyzed. Also, a user acceptance study was carried out. The evaluation showed that dynamic speed limits can be applied to achieve policy objectives, such as improving throughput and traffic safety. Road users appreciate the dynamic speed limits and adapt their behavior accordingly. Undesired side effects were shown to be very limited to nonexistent. ? 2011 IEEE.

Quantitative risk assessment of CO2 transport by pipelines : a review of uncertainties and their impacts

Scipedia content — Tue, 16 Feb 2021 12:30:28 +0100

systematic assessment, based on an extensive literature review, of the impact of gaps and uncertainties on the results of quantitative risk assessments (QRAs) for CO2 pipelines is presented. Sources of uncertainties that have been assessed are: failure rates, pipeline pressure, temperature, section length, diameter, orifice size, type and direction of release, meteorological conditions, jet diameter, vapour mass fraction in the release and the dose-effect relationship for CO2. A sensitivity analysis with these parameters is performed using release, dispersion and impact models. The results show that the knowledge gaps and uncertainties have a large effect on the accuracy of the assessed risks of CO2 pipelines. In this study it is found that the individual risk contour can vary between 0 and 204m from the pipeline depending on assumptions made. In existing studies this range is found to be between "1m and 7.2km. Mitigating the relevant risks is part of current practice, making them controllable. It is concluded that QRA for CO2 pipelines can be improved by validation of release and dispersion models for high-pressure CO2 releases, definition and adoption of a universal dose-effect relationship and development of a good practice guide for QRAs for CO2 pipelines. ? 2009 Elsevier B.V.

Trends in aircraft noise annoyance: The role of study and sample characteristics

Scipedia content — Tue, 16 Feb 2021 12:29:28 +0100

Recently, it has been suggested that the annoyance of residents at a given aircraft noise exposure level increases over the years. The objective of the present study was to verify the hypothesized trend and to identify its possible causes. To this end, the large database used to establish earlier exposure-response relationships on aircraft noise was updated with original data from several recent surveys, yielding a database with data from 34 separate airports. Multilevel grouped regression was used to determine the annoyance response per airport, after which meta-regression was used to investigate whether study characteristics could explain the heterogeneity in annoyance response between airports. A significant increase over the years was observed in annoyance at a given level of aircraft noise exposure. Furthermore, the type of annoyance scale, the type of contact, and the response percentage were found to be sources of heterogeneity. Of these, only the scale factor could statistically account for the trend, although other findings rule it out as a satisfactory explanation. No evidence was found for increased self-reported noise sensitivity. The results are of importance to the applicability of current exposure-annoyance relationships for aircraft noise and provide a basis for decisions on whether these need to be updated. ? 2011 Acoustical Society of America.

A Multifrequency Polarimetric SAR Processing Chain to Observe Oil Fields in the Gulf of Mexico

Scipedia content — Tue, 16 Feb 2021 12:27:43 +0100

Within the National Environmental Satellite, Data, and Information Service, National Oceanic and Atmospheric Ad- ministration, multiplatform synthetic aperture radar (SAR) im- agery is being used to aid posthurricane and postaccident response efforts in the Gulf of Mexico, such as in the case of the recent Deepwater Horizon oil spill. The main areas of interest related to such disasters are the following: 1) to identify oil pipeline leaks and other oil spills at sea and 2) to detect man-made metallic targets over the sea. Within the context of disaster monitoring and response, an innovative processing chain is proposed to observe oil fields (i.e., oil spills and man-made metallic targets) using both L- and C-band full-resolution and fully polarimetric SAR data. The processing chain consists of two steps. The first one, based on the standard deviation of the phase difference between the copolarized channels, allows oil monitoring. The second one, based on the different symmetry properties that characterize man- made metallic targets and natural distributed ones, allows man- made metallic target observation. Experiments, accomplished over single-look complex L-band Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) and C-band RADARSAT-2 fully polarimet- ric SAR data gathered in the Gulf of Mexico and related to the Deepwater Horizon accident, show the effectiveness of the proposed approach. Furthermore, the proposed approach, being able to process both L- and C-band fully polarimetric and full- resolution SAR measurements, can take full benefit of both the ALOS PALSAR and RADARSAT-2 missions, and therefore, it allows enhancing the revisit time and coverage which are very critical issues in oil field observation.

- Single European Sky - a possible regulatory framework for System Wide Information management (SWIM)

Scipedia content — Tue, 16 Feb 2021 12:25:51 +0100

Single European Sky ATM Research (SESAR) is the modernization programme of the European air traffic control infrastructure designed for the development of a new generation of air traffic management (ATM) technologies and procedures that will constitute the Single European Sky (SES) technologies and procedures. These will allow SES to cope with the increasing air traffic service demand predicted for the next twenty years. System Wide Information Management (SWIM) is a key part of SESAR; its objective is to create a new system of aeronautical information to increase efficiency and improve air transport safety. SWIM involves a group of independent users (Air Navigation Service Providers (ANSP), airlines, airports, etc.) that will exchange aeronautical information to ensure a safe gate-to-gate movement of an aircraft (flying object). SWIM architecture has many similarities with today��s Internet. SWIM, as with any other system created to provide a public service, needs a regulatory framework for governance and to establish the identification of responsibilities and liabilities of the parties involved in the programme. The conclusions of different debates regarding the governance of such organizations have led to the wide acceptance of the principle that for every organization where many parties operate with a certain degree of freedom, it is advisable to set up a system of guidelines, with mechanisms to encourage participating parties to conform, for example, to a code of conduct. In short, this article examines a possible system for regulating the relationships between all the parties involved, offering a comprehensive description of the SWIM programme, its possible governance, and the main elements for designing a regulatory framework.

Using eye tracker data in air traffic control

Scipedia content — Tue, 16 Feb 2021 12:18:06 +0100

Motivation/Research approach - An exploratory study was conducted to investigate whether eye movement metrics discriminate between different air traffic control tasks. Findings/Design - The results show the three tasks elicit different eye movement, as Yarbus (1967) also showed in static pictures, and that a number of eye tracking metrics demonstrate the differences. Research limitations/Implications - The effect was demonstrated using only one participant. The results can be used to further study various eye movement metrics. Originality/Value - The research demonstrates that different calculus distinguishes between tasks allowing targeting specific support given the type of task. Take away message - A combination of eye tracker metrics discriminates between tasks helping to provide flexible task support. ? 2011 Authors.

An agent-based micro-simulation framework for modeling of dynamic activity-travel rescheduling decisions

Scipedia content — Tue, 16 Feb 2021 12:17:29 +0100

The simultaneous implementation of daily activity-travel schedules of individuals in a given spatial environment generally gives rise to time- and location-varying congestion levels, which affect the conditions for subsequent activity and travel choices. Although such dynamics are commonly recognized, current activity-based models typically ignore the adaptive behaviour of individuals. In this article, we propose an agent-based simulation system that allows one to simulate, in addition to activity-scheduling behaviour, also the execution of schedules in space and time. Congestion levels at specific times and places emerge in the system and may lead to discrepancies between scheduled and actual activity and travel times. Agents respond to such unforeseen events by reconsidering an existing schedule (within-day re-planning) and by adapting their expectations about traffic conditions for subsequent days (learning). The system is illustrated using the activity-travel diary data collected in the Eindhoven region, the Netherlands, to better understand the choice of urban parks in the study area. We discuss the merits of the system for transport and spatial planning and identify avenues for future research.

Static Lightpath Establishment in Multilayer Traffic Engineering Under Physical Layer Impairments

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

This paper investigates the lightpath establishment problem in the optical layer, which arises in multilayer traffic engineering. The static version of the problem is considered, in which the set of requested lightpaths is known initially, and the objective is to set up as many of these lightpaths as possible by assigning the physical layer resources efficiently. In establishing the lightpaths, physical layer impairments are also considered, such that the bit error rates of all established lightpaths should remain within acceptable limits. A heuristic algorithm, called ROLE, is proposed for the solution of this problem. An integer linear programming (ILP) formulation for the static lightpath establishment with physical layer impairments is also developed, which considers the aggregated effect of physical layer impairments. This formulation is used as a performance benchmark for ROLE on smaller-size networks. It also provides upper bounds even when the ILP model cannot be solved to optimality. The performance of ROLE is close to the optimum solutions for all studied problem sets, for which the optimum solution can be obtained. ROLE significantly outperforms previously proposed algorithms in terms of the number of lightpaths established. The effect of switch cross-talk ratio on the problem solution is also investigated.

Removing Cross-Border Capacity Bottlenecks in the European Natural Gas Market-A Proposed Merchant-Regulatory Mechanism

Scipedia content — Tue, 16 Feb 2021 12:13:36 +0100

This publication is based on research carried out in the frame work of the Florence School of Regulation of the Robert Schuman Centre for Advanced Studies, European University Institute. We propose a merchant-regulatory framework to promote investment in the European natural gas network infrastructure based on a price cap over two-part tariffs. As suggested by Vogelsang (2001) and Hogan et al. (2010), a profit maximizing network operator facing this regulatory constraint will intertemporally rebalance the variable and fixed part of its two-part tariff so as to expand the congested pipelines, and converge to the Ramsey-Boiteaux equilibrium. We confirm this with actual data from the European natural gas market by comparing the bi-level price-cap model with a base case, a no-regulation case, and a welfare benchmark case, and by performing sensitivity analyses. In all cases, the incentive model is the best decentralized regulatory alternative that efficiently develops the European pipeline system.

Bottleneck congestion: Differentiating the coarse charge

Scipedia content — Tue, 16 Feb 2021 12:01:32 +0100

This discussion paper led to a publication in 'Transportation Research Part B: Methodological' . The traditional bottleneck model for road congestion promotes the implementation of a triangular, fully time varying, charge as the optimal solution for the road congestion externality. However, cognitive and technological barriers put a practical limit to the degree of differentiation real world implementations can handle. The traditional approach to accommodate for this concern has been a step toll, with the single step coarse charge as its simplest case. In this paper we study how efficiency of the coarse charge can be improved by differentiating its level and timing across groups of travellers. We use the traditional bottleneck model to analyse how the coarse charge can be differentiated over two groups of travellers assuming inelastic peak-hour demand. The results of our analysis indicate that differentiating the coarse charge across two groups of travellers considerably improves its efficiency without increasing cognitive effort and decision making costs for the individual traveller. A numeric illustration reveals a welfare gain of 69% of the first best charge, up from 53% for the generic coarse charge. This increase is similar to what is obtained by moving from the coarse charge to a generic two step toll. Once different groups have been defined, one could in fact achieve the same gains by temporal separation of drivers, for example by use of licence plate numbers. The presented charging regime has a considerable degree of flexibility with respect to share of travellers to attribute to each scheme, which further adds to its merits in practical applicability.

Vehicular Congestion Detection and Short-Term Forecasting: A New Model with Results

Scipedia content — Tue, 16 Feb 2021 11:57:08 +0100

While vehicular congestion is very often defined in terms of aggregate parameters, such as traffic volume and lane occupancies, based on recent findings, the interpretation that receives most credit is that of a state of a road where traversing vehicles experience a delay exceeding the maximum value typically incurred under light or free-flow traffic conditions. We here propose a new definition according to which a road is in a congested state (be it high or low) only when the likelihood of finding it in the same congested state is high in the near future. Based on this new definition, we devised an algorithm that, exploiting probe vehicles, for any given road 1) identifies if it is congested or not and 2) provides the estimation that a current congested state will last for at least a given time interval. Unlike any other existing approach, an important advantage of ours is that it can generally be applied to any type of road, as it neither needs any a priori knowledge nor requires the estimation of any road parameter (e.g., number of lanes, traffic light cycle, etc.). Further, it allows performing short-term traffic congestion forecasting for any given road. We present several field trials gathered on different urban roads whose empirical results confirm the validity of our approach.

An activity-based approach for complex travel behaviour modelling

Scipedia content — Tue, 16 Feb 2021 11:54:31 +0100

Purpose In this paper an activity-based modelling framework is presented. It enhances many of the characteristics of existing approaches and enables a more accurate travel demand modelling. Methods The model approach proposed explicitly takes into account the households�� role, as well as time and space constraints. Issues related to activity participation and activity planning are explicitly addressed with respect to the horizon of a whole week. The proposed framework allows to reproduce activity lists and activity patterns in an explicit and consistent way. As a consequence, time and mode characteristics of travel demand are more accurately computed. The approach has been designed in order to capture interactions among households members and to explicitly represent trip-chains and relationships between trips within activity patterns. In this paper a comprehensive formalisation of the modelling framework is presented and part of it is estimated on the basis of ad-hoc collected data. Application The modelling framework has been then applied to the Naples�� metropolitan area (southern Italy), a catchment area with about three million inhabitants. Results and Conclusions The proposed framework has shown a satisfying flexibility, as well as a good ability in reproducing real data. It seems to be a good compromise between accuracy and operative issues, which improves the range of reproducible mobility phenomena and the accuracy of this reproduction and at the same time it moves some step forward the practical applicability of activity-based approaches.

Document type: Article

SWATS: Wireless Sensor Networks for Steamflood and Waterflood Pipeline Monitoring

Scipedia content — Tue, 16 Feb 2021 11:53:03 +0100

State-of-the-art anomaly detection systems deployed in oilfields are expensive, not scalable to a large number of sensors, require manual operation, and provide data with a long delay. To overcome these problems, we design a wireless sensor network system that detects, identifies, and localizes major anomalies such as blockage and leakage that arise in steamflood and waterflood pipelines in oilfields. A sensor network consists of small, inexpensive nodes equipped with embedded processors and wireless communication, which enables flexible deployment and close observation of phenomena without human intervention. Our sensor-network-based system, Steamflood and Waterflood Tracking System (SWATS), aims to allow continuous monitoring of the steamflood and waterflood systems with low cost, short delay, and fine-granularity coverage while providing high accuracy and reliability. The anomaly detection and identification is challenging because of the inherent inaccuracy and unreliability of sensors and the transient characteristics of the flows. Moreover, observation by a single node cannot capture the topological effects on the transient characteristics of steam and water fluid to disambiguate similar problems and false alarms. We address these hurdles by utilizing multimodal sensing and multisensor collaboration, and exploiting temporal and spatial patterns of the sensed phenomena.

Modelling of accidental releases from a high pressure CO2 pipelines

Scipedia content — Tue, 16 Feb 2021 11:43:38 +0100

In the near future large quantities of CO2 will be transported over a large distance from Carbon dioxide Capture plants to onshore and off-shore underground Storage (CCS) sites. The risk assessments for the existing CO2 pipelines show distances to harmful threshold concentrations from 1 to 7.2 km. Such large differences in safety distances are not acceptable. For the design, construction and operation of new high pressure CO2 pipelines through populated areas it will be necessary to have a validated risk assessment model. This paper describes the applied models for the outflow and dispersion and the causes of the uncertainties in the outflow and dispersion of CO2 after an accidental release from a high pressure pipeline. ? 2011 Published by Elsevier Ltd.

A problem - structuring model for analyzing transportation - environment relationships

Scipedia content — Tue, 16 Feb 2021 11:43:25 +0100

This is the post-print version of the final paper published in European Journal of Operational Research. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2009 Elsevier B.V. This study discusses a decision support framework that guides policy makers in their strategic transportation related decisions by using multi-methodology. For this purpose, a methodology for analyzing the effects of transportation policies on environment, society, economy, and energy is proposed. In the proposed methodology, a three-stage problem structuring model is developed. Initially, experts�� opinions are structured by using a cognitive map to determine the relationships between transportation and environmental concepts. Then a structural equation model (SEM) is constructed, based on the cognitive map, to quantify the relations among external transportation and environmental factors. Finally the results of the SEM model are used to evaluate the consequences of possible policies via scenario analysis. In this paper a pilot study that covers only one module of the whole framework, namely transportation�Cenvironment interaction module, is conducted to present the applicability and usefulness of the methodology. This pilot study also reveals the impacts of transportation policies on the environment. To achieve a sustainable transportation system, the extent of the relationships between transportation and the environment must be considered. The World Development Indicators developed by the World Bank are used for this purpose.

A probabilistic measure of air traffic complexity in 3-D airspace

Scipedia content — Tue, 16 Feb 2021 11:25:56 +0100

In this paper, we propose a new method to evaluate air traffic complexity in 3-D airspace through a probabilistic measure of the airspace occupancy. The key novelty of the approach is that uncertainty in the future aircraft positions is explicitly accounted for when evaluating complexity. Analytic��though approximate��expressions of the complexity measure are derived. Prospective applications for the proposed complexity metric include the timely identification of those multi-aircraft conflict situations that would be difficult to solve because of limited maneuverability space, and the design of trajectories so as to avoid congested regions that would require many tactical maneuvers to pass them through. Numerical examples are provided to illustrate the approach. Copyright ? 2010 John Wiley & Sons, Ltd.

On-line battery identification for electric driving range prediction

Scipedia content — Tue, 16 Feb 2021 11:21:15 +0100

Hybrid and electric vehicles require accurate knowledge of the battery to make an educated guess about the expected electric driving range. Range prediction is complicated by the fact that batteries are subject to external influences and aging. Also the future driving behavior is often unknown. This paper presents a model-based identification method for online parameter estimation of Li-ion batteries. This allows range prediction to anticipate on all kinds of duty cycles as well as changing battery characteristics enforced by cell degradation. In the proposed methodology, parameters values of the battery model are frequently updated with the latest measurement data. Additional state observers are utilized to keep the dynamical states of the battery model up-to-date. Altogether, this offers robustness and accuracy under varying operating conditions and for the complete battery lifetime. Experimental results are presented to validate the proposed identification method. ? 2011 IEEE.

Modal-split effects of climate change: The effects of low water levels on the competitive position of inland waterway transport in the River Rhine area

Scipedia content — Tue, 16 Feb 2021 11:20:05 +0100

Future climate change is expected to affect inland waterway transport in most main natural waterways in Europe. For the river Rhine it is expected that, in summer, more and longer periods with low water levels will occur. In periods of low water levels inland waterway vessels have to reduce their load factors and, as a result, transport prices per tonne will increase. One possible consequence of these higher transport prices is a deterioration of the competitive position of inland waterway transport compared with rail and road transport, and thus a change in modal split. We study this issue using a GIS-based software model called NODUS which provides a tool for the detailed analysis of freight transportation over extensive multimodal networks. We assess the effect of low water levels on the costs of transport operations for inland waterway transport in North West Europe under several climate scenarios. It turns out, that the effect on the modal split is limited. Under the most extreme climate scenario, inland waterway transport would lose about 5.4% of the quantity that is currently being transported annually in the part of the European inland waterway transport market considered. The very dry year of 2003 can be seen as an analogue for this scenario. ? 2009 Elsevier Ltd.

The cost of pipeling climate change mitigation : an overview of the economics of CH4, CO2 and H2 transportation

Scipedia content — Tue, 16 Feb 2021 11:15:14 +0100

Gases like CH4, CO2 and H2 may play a key role in establishing a sustainable energy system: CH4 is the least carbon-intensive fossil energy resource; CO2 capture and storage can significantly reduce the climate footprint of especially fossil-based electricity generation; and the use of H2 as energy carrier could enable carbon-free automotive transportation. Yet the construction of large pipeline infrastructures usually constitutes a major and time-consuming undertaking, because of safety and environmental issues, legal and (geo)political siting arguments, technically un-trivial installation processes, and/or high investment cost requirements. In this article we focus on the latter and present an overview of both the total costs and cost components of the distribution of these three gases via pipelines. Possible intricacies and external factors that strongly influence these costs, like the choice of location and terrain, are also included in our analysis. Our distribution cost breakdown estimates are based on transportation data for CH4, which we adjust for CO2 and H2 in order to account for the specific additional characteristics of these two gases. The overall trend is that pipeline construction is no longer subject to significant cost reductions. For the purpose of designing energy and climate policy we therefore know in principle with reasonable certainty what the minimum distribution cost components of future energy systems are that rely on pipelining these gases. We describe the reasons why we observe limited learning-by-doing and explain why negligible construction cost reductions for future CH4, CO2 and H2 pipeline projects can be expected. Cost data of individual pipeline projects may strongly deviate from the global average because of national or regional effects related to the type of terrain, but also to varying costs of labor and fluctuating market prices of components like steel.

Commuting in Belgian metropolitan areas: the power of the Alonso-Muth model

Scipedia content — Tue, 16 Feb 2021 10:58:18 +0100

In order to understand patterns of urban commuter flows, insight is required into urban spatial structure (and vice versa). The present contribution first provides a concise overview of the theoretical perspectives from which economists and geographers approach commuting issues. Subsequently, the focus shifts to the classical spatial-economic urban models and how they explain commuter movements. We conduct a number of cluster analyses from which we are able to derive a commuting typology of city region areas. We conclude that distance (which also comprises journey time and proximity of traffic infrastructure), housing characteristics, housing environment, and income continue to play key roles in commuting patterns in the metropolitan areas under consideration.

ADC Non-Linearity Low-Cost Test Through a Simplified Double-Histogram Method

Scipedia content — Tue, 16 Feb 2021 10:55:12 +0100

This paper introduces a method to reduce the requirements of the test sources for evaluating the non-linearity characteristics of Analogue-to-Digital converters. The method is based on a non-interleaved Double-Histogram test independent of the test signal waveform. It has been validated by simulation results in a 16-bit pipeline A/D converter and by an experimental example using the AD6644 commercial converter.

This work has been partially supported by the Spanish TEC2007-68072 project.

Peer reviewed

Optimal Scheduling of Pipeline Systems with a Resource-Task Network Continuous-Time Formulation

Scipedia content — Tue, 16 Feb 2021 10:44:29 +0100

This work addresses the short-term scheduling problem involved in the pipeline transportation of refined petroleum products to distribution centers serving local markets. A new continuous-time formulation is proposed that can handle complex treelike systems involving multiple refineries and depots. The novelty concerns the modeling of the complex storage policy associated with the flow of multiple products inside the pipeline. This is accomplished through the use of real and accumulated volume resources for every product, coupled with filling, moving, and emptying tasks, under the scope of the resource?task network process representation. Computational studies are performed to compare the performance of the new approach to three models from the literature that rely on the concept of batches rather than events to model what is in reality a continuous system. The results show that the proposed approach is wider in scope with the typical drawback of being less efficient for structural subclasses of the gener...

The influence of (toll-related) travel costs in residential location decisions of households: A stated choice approach

Scipedia content — Tue, 16 Feb 2021 10:44:04 +0100

In this paper, we investigate the impact of travel costs, in particular toll costs, on the residential location choice of households, using a stated choice survey. Within the stated choice experiment, car drivers that frequently face traffic congestion, traded-off several trip-related (including toll costs) and house/location-related factors in their decision where to locate. If we look at the influence of different variables, toll and fuel costs seem to be important. Respondents are more sensitive to travel costs (i.e. toll and fuel costs) than to equally high (monthly) housing costs. Travel time appears to play a less important role, as indicated by a low value of time (VOT). In addition, location-related factors, such as the type of location and the number of bedrooms, turn out to be important factors as well. It can be concluded that respondents generally speaking prefer to pay higher housing costs and accept longer travel times to avoid (high) travel costs. Finally, if we look at the difference in preferences in relation to toll and fuel cost, we can conclude that toll costs are valued more negatively than fuel costs, although the differences are small. (C) 2010 Elsevier Ltd. All rights reserved.

Measuring destination competitiveness: An application of the Travel and Tourism competitiveness index (2007)

Scipedia content — Tue, 16 Feb 2021 10:43:28 +0100

This article evaluates 13 key factors that affect destination competitiveness and compares the competitiveness levels of EU countries with those of Turkey. The article also focuses on detecting the more or less effective determinants of destination competitiveness. Secondary data, comprised of the World Economic Forum's Travel and Tourism Competitiveness Index, were included in data analysis. Using this index, 28 countries were clustered according to their competitiveness scores. Cluster analysis and multidimensional scaling techniques were employed for an analysis of the findings. Results highlight that 3 clusters can be formed from the selected countries, and the factors which most affect the competitiveness of these countries are air transport infrastructure, natural and cultural resources, ground transport infrastructure, and health and hygiene. Results also indicate that Turkey receives the highest score only in price competitiveness; the image of Turkey as a low-priced country still exists in the international tourism marke

Air Traffic Control Service Quality Perceptions of Domestic Airline Pilots in Turkey

Scipedia content — Tue, 16 Feb 2021 10:42:14 +0100

WOS: 000297967200022

Numerous academic and industrial studies have been conducted and different approaches have been developed for the current air transportation system with its rapidly increasing traffic volume. Congestion due to capacity limitations is among the most basic problems in this system. Air traffic control services require communication between pilots and air traffic controllers at every stage of flight. Therefore, the inclusion of pilots and airlines in the decision-making process when addressing air traffic control system problems can increase customer satisfaction. This study aims to determine the perceived service quality of pilots in the process of receiving air traffic control services. A survey model is used in this study. First, using a semistructured interview technique with air traffic controllers and pilots, problems are detected and classified and then survey forms are prepared accordingly. A total of 116 questionnaires were studied and data from these questionnaires were tested through Microsoft Office Excel software. Answers to the questions are compared using a one-way analysis of variance test and checked to identify whether any differences exist among them. In general, training-based problems are detected among air traffic controllers, and the problems related to airspace technical equipment are found to be slightly above average. Although shortcomings regarding technical equipment can be solved in the short term, problems regarding controller training have to be solved in the long term.

Rewarding rush-hour avoidance: A study of commuters' travel behavior.

Scipedia content — Tue, 16 Feb 2021 10:38:59 +0100

Spitsmijden, peak avoidance in Dutch, is the largest systematic effort to date to study, in the field, the potential of rewards as a policy mean for changing commuter behavior. A 13 week field study was organized in The Netherlands with the purpose of longitudinally investigating the impacts of rewards on commuter behavior. Different levels and types of rewards were applied and behavior was tracked with state-of-the art detection equipment. Based on the collected data, which included also pre and post-test measurements, a mixed discrete choice model was estimated. The results suggest that rewards can be effective tools in changing commuting behavior. Specifically rewards reduce the shares of rush-hour driving, shift driving to off-peak times and increase the shares of public transport, cycling and working from home. Mediating factors include socio-demographic characteristics, scheduling constraints and work time flexibility, habitual behavior, attitudes to commuting alternatives, the availability of travel information and even the weather. The success of this study has encouraged adoption of rewards, as additional policy tools, to alleviate congestion, especially during temporary road closures.

GHG emission estimates for road transport in national GHG inventories

Scipedia content — Tue, 16 Feb 2021 10:38:35 +0100

The annual reporting procedures of the United Nations Framework Convention on Climate Change (UNFCCC) have now produced greenhouse gas (GHG) emission inventories from 40 so-called Annex I countries for 18 years. This article analyses a subset of these data: emissions from road transport. The article compares the reported data with the technical guidance on GHG emission inventories provided by the Intergovernmental Panel on Climate Change (IPCC). The analysis suggests that some countries use the IPCC's default emission factors, whereas other countries use country-specific values. In the case of diesel-fuelled road transport, the estimated emissions appear to be generally comparable between all countries for all years. For CO2 emissions from gasoline-fuelled road transport, the picture is less clear. The results suggest that the default emission factor for CO2 from motor gasoline as provided by the IPCC is about 3-5% too low. Countries that seem to apply this default value might therefore underestimate their emissions by the same percentage. The effect of this possible underestimate on trends is, however, very small. Despite the possible problem with the default emission factor, the quantification of the trend in emissions is only slightly influenced by this. ? 2011 Earthscan.

Transistor-Level Synthesis of Pipeline Analog-to-Digital Converters Using a Design-Space Reduction Algorithm

Scipedia content — Tue, 16 Feb 2021 10:31:42 +0100

novel transistor-level synthesis procedure for pipeline ADCs is presented. This procedure is able to directly map high-level converter specifications onto transistor sizes and biasing conditions. It is based on the combination of behavioral models for performance evaluation, optimization routines to minimize the power and area consumption of the circuit solution, and an algorithm to efficiently constraint the converter design space. This algorithm precludes the cost of lengthy bottom-up verifications and speeds up the synthesis task. The approach is herein demonstrated via the design of a 0.13 ?m CMOS 10 bits@60 MS/s pipeline ADC with energy consumption per conversion of only 0.54 pJ@1 MHz, making it one of the most energy-efficient 10-bit video-rate pipeline ADCs reported to date. The computational cost of this design is of only 25 min of CPU time, and includes the evaluation of 13 different pipeline architectures potentially feasible for the targeted specifications. The optimum design derived from the synthesis procedure has been fine tuned to support PVT variations, laid out together with other auxiliary blocks, and fabricated. The experimental results show a power consumption of 23 mW@1.2 V and an effective resolution of 9.47-bit@1 MHz. Bearing in mind that no specific power reduction strategy has been applied; the mentioned results confirm the reliability of the proposed approach.

Peer Reviewed

Soft Mobility and Pedestrian Networks in Urban Areas

Scipedia content — Tue, 16 Feb 2021 10:31:14 +0100

By referring to the wider strategies set up, starting from the middle of the Nineties, by the European cities to promote a sustainable urban mobility and to the more recent concept of soft mobility, which generally includes pedestrian and cycling mobility, this contribution focuses on pedestrian mobility in urban areas, outlining criteria and methods for planning and designing networks of urban public open spaces, such as roads and squares, devoted to an exclusive or prevailing pedestrian use. First of all, the paper analyzes the multiple roles played by roads and squares within the cities: “axes” supporting different mobility flows, including the pedestrian ones, and in the meanwhile urban places in which different activities (commercial activities, meeting, and so on) take place. Grounding on that, the main reasons driving toward an organization of such spaces as urban networks have been outlined. Then, some guidelines and methodological elements, both for planning pedestrian networks and designing their elements taking into account the correspondence between foreseen uses and spatial features of each element, have been provided. Furthermore, the links between the pedestrian networks and the main junctions of other urban mobility networks, as well as between the first ones and the urban contexts have been stressed. Suggested guidelines and methodological elements have been applied and tested both on historical and suburban areas of the city of Naples; nevertheless they represent only a first step towards the setting up of a method for pedestrian networks planning and design in urban areas.

Results of cooperative driving applications of the SPITS project

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

In this paper, the design and results of two cooperative driving applications are presented that both increase traffic flow on highways by reducing shockwave traffic jams and decrease the risk of head-on collisions. The first application is an advisory system based on vehicle-vehicle communication that showed positive results with a penetration level of 100% of equipped vehicles. The second application is both an advisory and automated system based on infrastructure-vehicle communication that showed positive results with a penetration level of 10%-30%.

Congestion and Awareness Control in Cooperative Vehicular Systems

Scipedia content — Tue, 16 Feb 2021 10:11:22 +0100

Cooperative vehicular systems have been identified as a promising solution to overcome the current and future needs for increasing traffic safety and efficiency, while providing infotainment and added-value services on the move. To achieve their objectives, cooperative vehicular systems will be based on wireless communications between vehicles and with other infrastructure nodes, and will have to deal with highly dynamic nodes, challenging propagation conditions, and stringent application requirements. By looking at cooperative applications and their data traffic, as well as the current and foreseen spectrum allocations for cooperative vehicular systems, there is a risk that the corresponding radio channels could easily be saturated if no control algorithms are used. The saturation of the radio channels would result in unstable vehicular communications, and thus in an inefficient operation of cooperative systems. As a prime example of upcoming ubiquitous networks contributing to the vision of ��a thousand radios per person,�� cooperative vehicular systems need to be designed to scale to high densities of radios without centralized coordination, while at the same time guaranteeing the requirements of the implemented applications and services, for example the stringent needs of active traffic safety applications. In this paper, we survey and classify various decentralized methods to control the load on the radio channels and to ensure each vehicle's capacity to detect and communicate with the relevant neighboring vehicles, with a particular focus on approaches based on transmit power and rate control. Finally, we discuss the open research challenges that are imposed by different application requirements and potential existing contradictions.

Modelling cooperative driving in congestion shockwaves on a freeway network

Scipedia content — Tue, 16 Feb 2021 10:02:04 +0100

The development of advanced driver assistance technology continues to proceed rapidly. Cooperative systems based on wireless communication are a specific form of advanced driver assistance that is currently evolving rapidly. A drawback in the development of such systems is that options for large scale field-testing and -development of these automated systems are limited. Traffic simulation however offers widespread options for testing. In this paper the effects of cooperative driving using cooperative adaptive cruise control (CACC) to influence congestion shockwaves are evaluated on a part of the Amsterdam freeway network. The effects of congestion shockwaves on a network scale can be different to uniform freeway sections due to interaction between varying traffic flows. The application of CACC to mitigate the negative effects of shockwaves on a network level are simulated and analysed in this research for varying levels of CACC penetration. The results are analysed on both a quantitative as well as qualitative level and give a deeper understanding into the possibilities of the mass application of CACC systems. ? 2011 IEEE.

Simulation-based Bayesian optimal design of aircraft trajectories for air traffic management

Scipedia content — Tue, 16 Feb 2021 09:57:24 +0100

SUMMARY In this paper we consider a specific Air Traffic Management problem, where multiple aircraft in as pecif ic region are required to reach ad if ferent target zone in minimum expected time, while maintaining safe separation. The problem is complicated by the presence of random wind disturbances. We propose a realistic policy to automatically generate optimal and safe manoeuvres for each aircraft. The parameters of the optimal policy are computed using a Sequential Monte Carlo approach. Copyright c ? 2010 John Wiley & Sons, Ltd.

Atividade de controle de tr��fego a��reo aumenta a capacidade de aten??o em controladores de v?o

Scipedia content — Mon, 15 Feb 2021 12:04:53 +0100

Air traffic controllers simultaneously develop complex and multiple tasks in the course of their activities. In this context, concern is raised over the high level of attention needed by these professionals which can ultimately be affected by stress and fatigue. Objectives: The objective of this study was to assess attention level in air traffic controllers (ATCo). Methods: 45 flight protection professionals were evaluated, comprising 30 ATCo, subdivided into ATCo with ten or more years in the profession (ATCo?10, n=15) and ATCo with less than ten years in the profession (ATCo "10, n=15) and 15 aeronautical information services operators (AIS), subdivided into AIS with ten years or more in the profession (AIS?10, n=8) and AIS with less than ten years in the profession (AIS "10, n=7), who were included as the control group. The digit symbol, d2 (the individual marks the letter d on a specific form containing 14 lines with 47 letters in each, maintaining focus on letter d followed by two dashes), forward digit span, backward digit span and PASAT (paced auditory serial addition test) attention tests were used. Kruskal-Wallis was used and data expressed as Median (Minimum and Maximum) with p"0.05. Results: The ATCo?10 presented greater focus of attention, sustained attention, mental manipulation and resistance to interference capacity compared to the AIS?10. Comparison of ATCo?10 to the AIS"10 showed they presented only greater resistance to interference, and when compared to the ATCo"10 presented lower focus. Conclusions: The air traffic control activity after ten years may be associated with a high level of attention. Resumo Os controladores de tr��fego a��reo (CTA) desenvolvem em suas atividades tarefas complexas e m��ltiplas simultaneamente. Nesse contexto, surge a preocupa??o com a necessidade de um maior n��vel de aten??o desses profissionais que pode ser afetada pelo estresse e fadiga. Objetivos: O objetivo deste trabalho foi avaliar o n��vel de aten??o em controladores de tr��fego a��reo (CTA). M��todos: Foram avaliados 45 profissionais de prote??o ao v?o, sendo 30 CTA, subdivididos em CTA com dez ou mais anos na profiss?o (CTA?10, n=15) e CTA com menos de dez anos na profiss?o (CTA"10, n=15) e 15 operadores de servi?os de informa??es aeron��uticas (AIS), subdivididos em AIS com dez anos ou mais na profiss?o (AIS?10, n=8) e AIS com menos de dez anos na profiss?o (AIS"10, n=7). Foram utilizados os testes de aten??o digit symbol, d2 (o indiv��duo deve marcar a letra d em um formul��rio espec��fico, contendo 14 linhas com 47 letras cada, mantendo sempre o foco na letra d que aparece acompanhada de dois tra?os), span de d��gitos em ordem direta e inversa e teste de depend��ncia auditiva para adi??o em s��rie (PASAT). Foi utilizado o Kruskal-Wallis e os dados expressos em mediana (m��nimo e m��ximo), p"0,05. Resultados: Os CTA?10 apresentaram maior foco de aten??o, manuten??o do foco, capacidade de manipula??o mental e resist��ncia �� interfer��ncia, quando comparados aos AIS?10, mas quando comparados aos AIS"10 apresentaram somente maior resist��ncia �� interfer��ncia e quando comparados aos CTA"10, menor foco. Conclus?es: A atividade de controle de tr��fego a��reo ap��s dez anos pode apresentar um alto n��vel de aten??o.

Document type: Article

Interfacility Helicopter Ambulance Transport of Neurosurgical Patients: Observations, Utilization, and Outcomes from a Quaternary Level Care Hospital

Scipedia content — Mon, 15 Feb 2021 11:01:30 +0100

Background: The clinical benefit of helicopter transport over ground transportation for interfacility transport is unproven. We sought to determine actual practice patterns, utilization, and outcomes of patients undergoing interfacility transport for neurosurgical conditions. Methodology/Principal Findings: We retrospectively examined all interfacility helicopter transfers to a single trauma center during 2008. We restricted our analysis to those transfers leading either to admission to the neurosurgical service or to formal consultation upon arrival. Major exclusion criteria included transport from the scene, death during transport, and transport to any area of the hospital other than the emergency department. The primary outcome was time interval to invasive intervention. Secondary outcomes were estimated ground transportation times from the referring hospital, admitting disposition, and discharge disposition. Of 526 candidate interfacility helicopter transfers to our emergency department in 2008, we identified 167 meeting study criteria. Seventy-five (45%) of these patients underwent neurosurgical intervention. The median time to neurosurgical intervention ranged from 1.0 to 117.8 hours, varying depending on the diagnosis. For 101 (60%) of the patients, estimated driving time from the referring institution was less than one hour. Four patients (2%) expired in the emergency department, and 34 patients (20%) were admitted to a non-ICU setting. Six patients were discharged home within 24 hours. For those admitted, in-hospital mortality was 28%. Conclusions/Significance: Many patients undergoing interfacility transfer for neurosurgical evaluation are inappropriately triaged to helicopter transport, as evidenced by actual times to intervention at the accepting institution and estimated ground transportation times from the referring institution. In a time when there is growing interest in health care cost containment, practitioners must exercise discretion in the selection of patients for air ambulance transport��particularly when it may not bear influence on clinical outcome. Neurosurgical evaluation via telemedicine may be one strategy for improving air transport triage.

Document type: Article

Field test on visibility at cycle crossings at night

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

The main purpose of the study was to compare the night-time visibility distance of cycle crossings to the night-time visibility distance of bicyclists at the corresponding cycle crossings. This was tested both for dry and wet road surface. The test was carried out as a field study with twelve participants being passengers in an instrumented car. The test route included nine cycle crossings, that all were combined with pedestrian crossings. The participants individually pushed a noiseless button when they saw a dummy bicyclist standing still at a crossing, in part one, and when they saw a correctly marked cycle crossing in part two. Visibility distances to bicyclist dummies and cycle crossings were measured. Half of the participants experienced dry road surface and the other half wet road surface. An analysis of variance was conducted with a split plot design of group (wet / dry road surface) �� target (bicyclist dummy / cycle crossing) �� crossing (9 different cycle crossings). The bicyclist dummies were detected at a significantly longer distance (mean 59.1?m, standard error 2.9?m) than the cycle crossings (mean 17.5?m, standard error 1.0?m). The road condition (wet/dry) only had an effect on the visibility of cycle crossings. The field test showed that bicyclists are seen at longer distances than cycle crossings combined with pedestrian crossings in Sweden at night-time.

Document type: Article

Logistics FDI in Italy: integration strategies and motivations

Scipedia content — Mon, 15 Feb 2021 10:01:32 +0100

The aim of the paper is to investigate the integration strategies (vertical, horizontal and conglomerate) undertaken by foreign logistics multinational enterprises (MNE) in Italy, and analyze the related motivations. The empirical analysis consists of descriptive statistics, which makes use of the LogINT database, monitoring inward logistics foreign direct investments (FDI) in Italy in 2000�C2008, and of additional information on the foreign logistics MNE��s integration strategies. It results that inward logistics FDI are mainly horizontal, that is they operate in the same parent company��s sub-industry, and are mainly driven by market power�� and economies of scale�� increase. Vertical integrations, which are in a logistics sub-industry differing from the MNE��s one, are driven by competitive considerations, by the need to reach economies of scope and reduce transaction costs. The conglomerate integrations, which are mainly undertaken by financial and real estate investors and manufacturing firms, are motivated by the need to achieve economies of scale and reduce transaction costs. The empirical analysis has showed that the motivations driving inward FDI are often multiple and differ according to the peculiarities of the sub-industry.

Document type: Article

Ageing Testing Procedures on Lithium Batteries in an International Collaboration Context

Scipedia content — Mon, 15 Feb 2021 09:59:01 +0100

The widespread introduction of electrically-propelled vehicles is currently part of many political strategies and introduction plans. These new vehicles, ranging from limited (mild) hybrid to plug-in hybrid to fully-battery powered, will rely on a new class of advanced storage batteries, such as those based on lithium, to meet different technical and economical targets. The testing of these batteries to determine the performance and life in the various applications is a time-consuming and costly process that is not yet well developed. There are many examples of parallel testing activities that are poorly coordinated, for example, those in Europe, Japan and the US. These costs and efforts may be better leveraged through international collaboration, such as that possible within the framework of the International Energy Agency (IEA). Here, a new effort is under development that will establish standardized, accelerated testing procedures and will allow battery testing organizations to cooperate in the analysis of the resulting data. This paper reviews the present state-of-the-art in accelerated life testing procedures in Europe, Japan and the US. The existing test procedures will be collected, shortly described, compared and analyzed with the goal of defining a process and a possible working plan for the establishment of an international collaboration.

Document type: Article

Identifying and Tracking Pedestrians Based on Sensor Fusion and Motion Stability Predictions

Scipedia content — Fri, 12 Feb 2021 16:19:05 +0100

The lack of trustworthy sensors makes development of Advanced Driver Assistance System (ADAS) applications a tough task. It is necessary to develop intelligent systems by combining reliable sensors and real-time algorithms to send the proper, accurate messages to the drivers. In this article, an application to detect and predict the movement of pedestrians in order to prevent an imminent collision has been developed and tested under real conditions. The proposed application, first, accurately measures the position of obstacles using a two-sensor hybrid fusion approach: a stereo camera vision system and a laser scanner. Second, it correctly identifies pedestrians using intelligent algorithms based on polylines and pattern recognition related to leg positions (laser subsystem) and dense disparity maps and u-v disparity (vision subsystem). Third, it uses statistical validation gates and confidence regions to track the pedestrian within the detection zones of the sensors and predict their position in the upcoming frames. The intelligent sensor application has been experimentally tested with success while tracking pedestrians that cross and move in zigzag fashion in front of a vehicle.

Document type: Article

A multiagent simulator for supporting logistic decisions of unloading petroleum ships in habors

Scipedia content — Fri, 12 Feb 2021 16:15:53 +0100

This work presents and evaluates the performance of a simulation model based on multiagent system technology in order to support logistic decisions in a harbor from oil supply chain. The main decisions are concerned to pier allocation, oil discharge, storage tanks management and refinery supply by a pipeline. The real elements as ships, piers, pipelines, and refineries are modeled as agents, and they negotiate by auctions to move oil in this system. The simulation results are compared with results obtained with an optimization mathematical model based on mixed integer linear programming (MILP). Both models are able to find optimal solutions or close to the optimal solution depending on the problem size. In problems with several elements, the multiagent model can find solutions in seconds, while the MILP model presents very high computational time to find the optimal solution. In some situations, the MILP model results in out of memory error. Test scenarios demonstrate the usefulness of the multiagent based simulator in supporting decision taken concerning the logistic in harbors. O objetivo deste artigo �� apresentar e avaliar o desempenho de um modelo de simula??o baseado em sistemas multiagentes para auxiliar a tomada de decis?o na aloca??o de petr��leo em complexos portu��rios. Os diversos elementos do problema s?o modelados como agentes e negociam por meio de leil?es a aloca??o dos invent��rios de ��leo. Os resultados obtidos s?o comparados com resultados gerados por modelos de otimiza??o matem��tica, estes baseados em programa??o linear inteira mista. Esses modelos s?o capazes de encontrar solu??es ��timas ou pr��ximas da ��tima dependendo do tamanho da inst?ncia testada. Em problemas com muitos navios e tanques, o modelo baseado em sistema multiagente encontrou solu??es em segundos, enquanto os modelos baseados em otimiza??o matem��tica apresentaram problemas de tempo computacional e falta de mem��ria, n?o encontrando a solu??o ��tima. Os diversos exemplos aqui apresentados evidenciam a necessidade do modelo de simula??o baseado em multiagentes no aux��lio a tomada de decis?es log��sticas de porto

Document type: Article

Evaluating impact of demerit points system on speeding behavior of drivers

Scipedia content — Fri, 12 Feb 2021 16:14:08 +0100

Objective The objective of this research was to evaluate the immediate impact of the demerit points system on speeding behavior of drivers in Al Ain. Al Ain is the fourth largest city in the United Arab Emirates, located about 120 Km from Dubai.

Document type: Article

Seeing through the Ground: The Potential of Gravity Gradient as a Complementary Technology

Scipedia content — Fri, 12 Feb 2021 16:02:21 +0100

In the UK there is a huge legacy of buried utility service pipelines and cables beneath our streets and new services, such as fibre optic cables, are being added all the time. Much of this utility network is poorly mapped and recorded. It is therefore important to accurately locate and map these services to aid the installation of new, and repair and maintenance of existing, assets. This will help avoid damage to adjacent services and reduce the direct and social costs associated with finding buried utilities. This paper describes two major UK initiatives��Mapping the Underworld (MTU) and Gravity Gradient Technologies and Opportunities Programme (GG-TOP)��that aim to improve the way that we locate, map, and share information on buried utility services. MTU aims to develop a multisensor device to locate buried services, while GG-TOP aims to develop gravity gradient technology to deliver a (three orders of magnitude) step change in performance.

Document type: Article

Overcoming the barriers to implementing urban road user charging schemes

Scipedia content — Fri, 12 Feb 2021 14:53:20 +0100

Urban road user charging offers the potential to achieve significant improvements in urban transport, but is notoriously difficult to implement. Cities need guidance on the range of factors to be considered in planning and implementing such schemes. This paper summarises the results of a 3 year programme which has collated evidence on the issues of most concern to cities. A state of the art report has provided evidence on 14 themes, ranging from objectives and design to implementation and evaluation. A set of 16 case studies has reviewed experience in design and implementation across Europe. The paper summarises their findings, provides references to more detailed information, presents the resulting policy recommendations to European, national and local government, and outlines the areas in which further research is needed.

Document type: Article

Development and Evaluation of a Control System for Regional Traffic Management

Scipedia content — Fri, 12 Feb 2021 14:50:00 +0100

Traffic congestion is a worsening problem in metropolitan areas which will require integrated regional traffic control systems to improve traffic conditions. This paper presents a regional traffic control system which can detect incident conditions and provide integrated traffic management during nonrecurrent congestion events. The system combines advanced artificial intelligence techniques with a traffic performance model based on HCM equations. Preliminary evaluation of the control system using traffic microsimulation demonstrates that it has the potential to improve system conditions during traffic incidents. In addition, several enhancements were identified which will make the system more robust in a real traffic control setting. An assessment of the control system elements indicates that there are no substantial technical barriers in implementing this system in a large traffic network.

Document type: Article

Sampling-based threat assessment algorithms for intersection collisions involving errant drivers

Scipedia content — Fri, 12 Feb 2021 14:16:09 +0100

This paper considers the decision-making problem for a vehicle crossing a road intersection in the presence of other, potentially errant, drivers. This problem is considered in a game-theoretic framework, where the errant drivers are assumed to be capable of causing intentional collisions. Our approach is to simulate the possible behaviors of errant drivers using RRT-Reach, a modified application of rapidly-exploring random trees. A novelty in RRT-Reach is the use of a dual exploration-pursuit mode, which allows for efficient approximation of the errant reachability set for some fixed time horizon. Through simulation and experimental results with a small autonomous vehicle, we demonstrate that this threat assessment algorithm can be used in real-time to minimize the risk of collision.

Document type: Article

The State of the Art in Fuel Cell Condition Monitoring and Maintenance

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

Fuel cell vehicles are considered to be a viable solution to problems such as carbon emissions and fuel shortages for road transport. Proton Exchange Membrane (PEM) Fuel Cells are mainly used in this purpose because they can run at low temperatures and have a simple structure. Yet to make this technology commercially viable, there are still many hurdles to overcome. Apart from the high cost of fuel cell systems, high maintenance costs and short lifecycle are two main issues need to be addressed. The main purpose of this paper is to review the issues affecting the reliability and lifespan of fuel cells and present the state of the art in fuel cell condition monitoring and maintenance. The Structure of PEM fuel cell is introduced and examples of its application in a variety of applications are presented. The fault modes including membrane flooding/drying, fuel/gas starvation, physical defects of membrane, and catalyst poisoning are listed and assessed for their impact. Then the relationship between causes, faults, symptoms and long term implications of fault conditions are summarized. Finally the state of the art in PEM fuel cell condition monitoring and maintenance is reviewed and conclusions are drawn regarding suggested maintenance strategies and the optimal structure for an integrated, cost effective condition monitoring and maintenance management system.

Document type: Article

A Neural Network Based Traffic-Flow Prediction Model

Scipedia content — Fri, 12 Feb 2021 14:10:34 +0100

Prediction of traffic-flow in Istanbul has been a great concern for planners of the city. Istanbul as being one of the most crowded cities in the Europe has a rural population of more than 10 million. The related transportation agencies in Istanbul continuously collect data through many ways thanks to improvements in sensor technology and communication systems which allow to more closely monitor the condition of the city transportation system. Since monitoring alone cannot improve the safety or efficiency of the system, those agencies actively inform the drivers continuously through various media including television broadcasts, internet, and electronic display boards on many locations on the roads. Currently, the human expertise is employed to judge traffic-flow on the roads to inform the public. There is no reliance on past data and human experts give opinions only on the present condition without much idea on what will be the likely events in the next hours. Historical events such as school-timings, holidays and other periodic events cannot be utilized for judging the future traffic-flows. This paper makes a preliminary attempt to change scenario by using artificial neural networks (ANNs) to model the past historical data. It aims at the prediction of the traffic volume based on the historical data in each major junction in the city. ANNs have given very encouraging results with the suggested approach explained in the paper. ? Association for Scientific Research.

Document type: Article

Piloting smart safe school bus: exploration of security gains from implementation of a driver support system, additional technical equipment and intelligent bus stops

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

Purpose Road crash statistics reveal that school children are frequent victims and the most risky situation is when the child is outside the bus. The aim of this pilot study was to explore possible changes in speed, implementation of routines, hazard detection and child security gains from a driver support system integrated with intelligent bus stops and additional technical equipment. Methods In total, 130 children with transmitters were using two specially equipped busses and bus stops. Speed of oncoming and overtaking cars, implementation of routines, the possibilities to discover potential hazards and experienced stress in the children were analysed by speed measurements, diary notes, questionnaires and focus group interviews. Results This pilot study exploration showed that the speeds of other road users were reduced at one of two bus stops. The driver support system was frequently used in all its parts and was considered useful by the bus drivers. It also raised the level of routines and allowed the drivers to survey the children. Children reported feeling more secure with the system running and experienced less stress as a consequence of it. Conclusion This pilot study shows that the evaluated systems may have the ability to reduce speed of other road users, raise the level of routines and make children feel more secure. Further studies are needed that apply a holistic approach on school transportation safety and security.

Document type: Article

Study on the Electric Vehicle Wireless Power Supply Technology and System Based on ICPT

Scipedia content — Fri, 12 Feb 2021 13:52:49 +0100

The electric vehicle power supply technology based on wireless power transfer (EVPS-WPT) has several advantages over conventional energy transmission using wires and connectors, such as flexibility, convenience, safety, reliability and all-weather operation, etc. The development of EVPS-WPT will certainly promote the popularization and industrialization of EVs. The fundamental structure of electric vehicle wireless power supply system based on ICPT (EVPS-ICPT) is described firstly in this paper. A supposed dynamic battery charging system for electric vehicles based on ICPT (EVC-ICPT-D) is proposed to explain some concepts more clearly. The main circuit topology of EVPS-ICPT system is also discussed and selected. As the focus of this paper, the key techniques for EVPS-ICPT system are discussed and analyzed in the round.

Document type: Article

Nonlinear Autoregressive Conditional Duration Models for Traffic Congestion Estimation

Scipedia content — Fri, 12 Feb 2021 13:26:06 +0100

The considerable impact of congestion on transportation networks is reflected by the vast amount of research papers dedicated to congestion identification, modeling, and alleviation. Despite this, the statistical characteristics of congestion, and particularly of its duration, have not been systematically studied, regardless of the fact that they can offer significant insights on its formation, effects and alleviation. We extend previous research by proposing the autoregressive conditional duration (ACD) approach for modeling congestion duration in urban signalized arterials. Results based on data from a signalized arterial indicate that a multiregime nonlinear ACD model best describes the observed congestion duration data while when it lasts longer than 18 minutes, traffic exhibits persistence and slow recovery rate.

Document type: Article

Evaluating the achievements and impacts of EC framework programme transport projects

Scipedia content — Fri, 12 Feb 2021 13:22:10 +0100

Purpose: The purpose of this paper is to present what kind of elements and evaluation methods should be included into a framework for evaluating the achievements and impacts of transport projects supported in EC Framework Programmes (FP). Further, the paper discusses the possibilities of such an evaluation framework in producing recommendations regarding future transport research and policy objectives as well as mutual learning for the basis of strategic long term planning. Methods: The paper describes the two-dimensional evaluation methodology developed in the course of the FP7 METRONOME project. The dimensions are: (1) achievement of project objectives and targets in different levels and (2) research project impacts according to four impact groups. The methodology uses four complementary approaches in evaluation, namely evaluation matrices, coordinator questionnaires, lead user interviews and workshops. Results: Based on the methodology testing, with a sample of FP5 and FP6 projects, the main results relating to the rationale, implementation and achievements of FP projects is presented. In general, achievement of objectives in both FPs was good. Strongest impacts were identified within the impact group of management and co-ordination. Also scientific and end-user impacts of the projects were adequate, but wider societal impacts quite modest. Conclusions: The paper concludes with a discussion both on the theoretical and practical implications of the proposed methodology and by presenting some relevant future research needs.

Document type: Article

Data accuracy on automatic traffic counting: the SMART project results

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

"jats:p"In this paper the results of an experimental survey on traffic monitoring devices, named SMART Project, are presented. Aim of the project was to define the requirements to be applied to traffic technologies to match specific applications. The project involved the construction of a test site on a main road, where seven different traffic monitoring systems were installed. A 1 year survey was carried out to assess technologies response to environmental and mechanical solicitations. A reference system specifically devoted to check and validate the devices under test was designed for the project. Test procedures were also developed to control the results achieved. The outcomes accomplished for vehicles counting are described in details in the essay hereunder.

Document type: Article

Ditchwall Database For the Normal Wells To Zama Oil Pipeline, Volume Iii: Summary of Ditchwall Database Evaluation

Scipedia content — Thu, 11 Feb 2021 14:43:27 +0100

Analysis of Filesystem Utilization by the ?Ensemble of Models? Approach (U)

Scipedia content — Thu, 11 Feb 2021 14:39:47 +0100

In order to execute Uncertainty Quantification (UQ) studies, the number of reads placed on the filesystem will increase. This document works through the file I/O for a climatology UQ study. The utilization of the filesystem for the above discussed will be similar for ICF and Stockpile Stewardship applications. The current state of the art for the quantification of uncertainty of a multi-physics simulation code is the utilization of an ensemble of models approach. As an overview of the ensemble of models approach, a set of uncertain input parameters is identified along with an identified set of observational and output parameters. The model is computed n number of times with each ensemble simulation using a unique set of parametric combinations of input parameters thereby creating an ensemble of simulations. Response surface models (also known as statistical emulator models, surrogate models, or meta models) are trained using the ensemble results. The response models are then convolved with observational data to further constrain input parameters and to create uncertainty bounds on the model outputs. Using the Community Climate System Model (CCSM) specifically the atmospheric component of CCSM, the Community Atmospheric Model (CAM), as the model of interest, this document provides a rough modelmore » of the demands on a filesystem that is needed to execute a UQ study on CAM. Each ensemble simulation consists of 12 simulation years and uses 384 processors on the Atlas machine. The LLNL UQ Pipeline is LLNL's standard tool to execute UQ studies. The UQ Pipeline possesses the capability to execute the ensemble simulations on LLNL's diverse set of HPC environments, produce response models, generate uncertainty bounds, and analyze the results. The process executing the LLNL UQ Pipeline is run on a different compute node from the set of concurrent, executing ensemble simulations.« le

Issues for northern pipelines: a review of environmental assessments, regulatory and monitoring reports from the 1970s, 80s and 90s

Scipedia content — Thu, 11 Feb 2021 14:38:53 +0100

International study of telluric current effects on pipelines: final report, volumes 1-3

Scipedia content — Thu, 11 Feb 2021 14:38:43 +0100

Norman Wells To Zama Oil Pipeline Permafrost and Terrain Research and Monitoring Program: Site Establishment Report

Scipedia content — Thu, 11 Feb 2021 14:25:28 +0100

Frost heave and northern pipelines, state of the art and status of research - three contributing studies

Scipedia content — Thu, 11 Feb 2021 14:23:42 +0100

Survey of expert opinion on permafrost and geotechnical issues for northern pipelines

Scipedia content — Thu, 11 Feb 2021 14:23:27 +0100

Driver behavior~Key to safe highway design

Scipedia content — Thu, 11 Feb 2021 14:17:13 +0100

Empirical Observation of the Impact of Traffic Oscillations on Freeway Safety

Scipedia content — Thu, 11 Feb 2021 14:12:41 +0100

Traffic oscillations are typical features of congested traffic flow that are characterized by recurring decelerations followed by accelerations (stop-and-go driving). The negative environmental impacts of these oscillations are widely accepted, but their impact on traffic safety has been debated. This report describes the impact of freeway traffic oscillations on traffic safety. This study employs a matched case-control design using high resolution traffic and crash data from a freeway segment. Traffic conditions prior to each crash were taken as cases, while traffic conditions during the same periods on days without crashes were taken as controls. These were also matched by presence of congestion, geometry and weather. A total of 82 cases and about 80,000 candidate controls were extracted from more than three years of data from 2004 to 2007. Conditional logistic regression models were developed based on the case-control samples. To verify consistency in the results, 20 different sets of controls were randomly extracted from the candidate pool. The results reveal that the standard deviation of speed (thus, oscillations) is a significant variable, with an average odds ratio of about 1.08. This implies that the odds of a (rear-end) crash occurring increases by about 8 percent with an additional unit increase in the standard deviation of speed. The average traffic states prior to crashes were less significant than the speed variations in congestion.

Addressing Liability of Automated Systems in Air Traffic Management

Scipedia content — Mon, 08 Feb 2021 12:36:40 +0100

In the current operational scenario of Air Traffic Management (ATM), liability is mainly allocated to the operators who are responsible for air traffic control and air navigation. However, this scenario will rapidly change: the adoption of new technologies with high automation levels is likely to raise new legal issues related to liability. The paper presents an outline of the issues of liability in relation to automation, focusing on the concept of autonomy and on the delegation of tasks to automatic systems or to hybrid human�\machine systems. Finally a proposal to handle such issues is presented, based on a model of ATM as a socio-technical system, where the allocation of liabilities may be seen as a governance mechanism enabling the enhancement of the functioning of ATM.

Towards User-Centred Development of Integrated Information, Warning, and Intervention Strategies for Multiple ADAS in the EU Project interactIVe

Scipedia content — Mon, 08 Feb 2021 12:35:09 +0100

In the increasingly fast strive for new advanced driver assistance systems and a continuously higher automation of the driving task, it is essential not to lose sight of the most important factor: the driver. Therefore, we have to develop interaction strategies that center around the user perspective without loosing sight of the technological availability. Individual design for a certain assistance function must be balanced with the integrated and compatible design of multiple functions in several vehicles. This paper details the iterative interactIVe approach and details how the strategy space was structured to find possible common elements, derive generic interaction strategies universal to several or all systems, and identify the main research questions for the further course of the project.

Risk Analysis of Changing and Evolving Systems Using CORAS

Scipedia content — Mon, 08 Feb 2021 12:34:02 +0100

Risk analysis is the identification and documentation of risks with respect to an organisation or a target system. Established risk analysis methods and guidelines typically focus on a particular system configuration at a particular point in time. The resulting risk picture is then valid only at that point in time and under the assumptions made when it was derived. However, systems and their environments tend to change and evolve over time. In order to appropriately handle change, risk analysis must be supported with specialised techniques and guidelines for modelling, analysing and reasoning about changing risks. In this paper we introduce general techniques and guidelines for managing risk in changing systems, and then instantiate these in the CORAS approach to model-driven risk analysis. The approach is demonstrated by a practical example based on a case study from the Air Traffic Management (ATM) domain.

Using BGP-4 to Migrate to a Future Internet

Scipedia content — Mon, 08 Feb 2021 12:32:16 +0100

The Internet has evolved to become one of the most critical communication infrastructures in the planet. And yet, some of its underlying concepts and protocols do not provide the adequate level of reliability for such an essential role in global communications. The inter-domain routing protocol of the Internet, Border Gateway Protocol (BGP-4), is being used with varying degree of success for tasks for which it was not originally designed, such as Traffic Engineering. This paper presents a rationalised view of the different functions implemented by routing nowadays and proposes the use of Autonomous System Compartments. The Autonomous System (AS) Compartments imply a new routing hierarchy over the traditional BGP-4 routing, where specific functionalities like Traffic Engineering can be better controlled and additional routing incentives can be introduced. The FP-7 project 4WARD is working on new communication paradigms for the Future Internet and AS Compartments are a choice to contain the Generic Path (GP) concept developed by it. In order to provide inter-domain capabilities and a migration tool to connect GP islands, the multiprotocol mechanism of the BGP-4 routing is used. This paper presents the AS Compartment concept and the integration of Generic Paths in it, as well as an implementation of the GP-BGP concept for the J-Sim simulator (JSIM) environment.

Summarization and Analysis of Network Traffic Flow Records

Scipedia content — Mon, 08 Feb 2021 12:29:42 +0100

Current network measurement systems are becoming highly sophisticated, producing huge amounts of convoluted measurement data and statistics. As a very common case, those networks implementing statistics reporting based on the NetFlow [15] technology can generate several GBs of data on a daily basis. In addition, these measurements are often very hard to interpret. In this chapter we describe a method that provides linguistic summaries of network traffic measurements as well as a procedure for finding hidden facts in the form of linguistic association rules. Thus, here we address an association rules mining problem. The method is suitable for summarization and analysis of network measurements at the flow level. As a first step, fuzzy linguistic summaries are applied to analyze and extract concise and human consistent summaries from NetFlow collections. Then, a procedure for mining hidden facts in network flow measurements in the form of fuzzy association rules is developed. The method is applied to a wide set of heterogeneous flow measurements, and is shown to be of practical application to network operation and traffic engineering [6, 5], where it can help solve a number of current issues. © 2011 Springer-Verlag Berlin Heidelberg. Peer Reviewed

Air demand modelling: overview and application to a developing regional airport

Scipedia content — Mon, 08 Feb 2021 12:29:31 +0100

4 Air demand modelling: overview and application to a developing regional airport M. Nadia Postorino University ‘Mediterranea’ of Reggio Calabria, Italy Abstract Air demand forecast at airports is animportant problem for the airport management and also for the regulator that has to plan a homogeneousdevelopment of the overall transport system. The current tendency is towards airport privatization; then, the goal to increase the served demand is one of the most important together with the progress of non-aviation activities. The evolution of the air transport system both in terms of low-cost companies, thatgenerally use regional airports, and new technologies (as regional jets) has given a further impulse to the development of planning methodologies able tosupportdecisions for an efficient distribution of resources. Regional airports can play an important role in this new background if the most suitable developing strategiesare identified. This chapter wants togive a generaloverview about the problemof the air demand modelling, both in terms of theoretical approaches andpractical problems. Models are classified with respect todifferent criteria, and the most suitable models for eachplanning level are also identified.Anapplication toa regional airport inSouthern Italy is also presented in order to testsome of the described approaches and to obtainpractical indications aboutapplied models and developing strategies tobe used.

Differential transform method for mathematical modeling of jamming transition problem in traffic congestion flow

Scipedia content — Mon, 08 Feb 2021 12:27:36 +0100

In this paper we aim to find an analytical solution for jamming transition in traffic flow. Generally the Jamming Transition Problem (JTP) can be modeled via Lorentz system. So, in this way, the governing differential equation achieved is modeled in the form of a nonlinear damped oscillator. In current research the authors utilized the Differential Transformation Method (DTM) for solving the nonlinear problem and compared the analytical results with those ones obtained by the 4th order Runge-Kutta Method (RK4) as a numerical method. Further illustration embedded in this paper shows the ability of DTM in solving nonlinear problems when a so accurate solution is required. In this paper we aim to find an analytical solution for jamming transition in traffic flow. Generally the Jamming Transition Problem (JTP) can be modeled via Lorentz system. So, in this way, the governing differential equation achieved is modeled in the form of a nonlinear damped oscillator. In current research the authors utilized the Differential Transformation Method (DTM) for solving the nonlinear problem and compared the analytical results with those ones obtained by the 4th order Runge-Kutta Method (RK4) as a numerical method. Further illustration embedded in this paper shows the ability of DTM in solving nonlinear problems when a so accurate solution is required.

Development of Regional Airports in EU

Scipedia content — Mon, 08 Feb 2021 12:25:24 +0100

This paper describes how a suitable development of regional airports in large areas, such as continental areas, can be obtained if there are appropriate polices addressed to achieve this goal. In the specific case of the European Union (EU), some specific programs at the European level, such as the Single European Sky and the Trans-European Network Programs, will have many implications for the development of regional airports as well as the relationships between regional airports and low-cost carriers. Regional airports can play an important role in reducing congestion peaks at main airports, particularly in the light of an integrated transport network where many modes coexist and can integrate or substitute each other. Particularly, high-speed rail can improve the airport accessibility by increasing its catchment area or represent an alternative to the air mode.

Design Techniques and Considerations for a 1.2V 10bit CMOS Pipeline ADC

Scipedia content — Mon, 08 Feb 2021 10:11:01 +0100

1.2V 10bit 83MS/s pipeline ADC implemented in 130nm CMOS Technology is described with practical design techniques and considerations. Emphasis was placed on noise analysis and capacitance optimization, which helps to reduce both die area and power consumption. Design experiences of operational amplifier, comparator and switches were also shared. This design achieves INL and DNL of +0.65/-0.53LSB and +0.33/-0.33LSB respectively, while SNDR is 57.7dB.

Technical feasibility study for a solar energy system at Amsterdam Airport Schiphol (AAS)

Scipedia content — Mon, 08 Feb 2021 10:00:36 +0100

This work arises within the framework of the introduction of renewable energies at Amsterdam Airport Schiphol (AAS) and the focus is on the technical feasibility of a solar energy system (SES) on ground level. The flight safety must always be guaranteed if solar panels are implemented on AAS. The radiation reflection of solar panels according to the optical effect towards the pilot of an airplane and the line of sight of the Air traffic tower has been studied. Also the constraints for installing an "object" at the Airport have to be taken into account. This should lead to an overall impression of the potential of solar panels that can be orientated on ground level. A complete model of a solar energy system is designed: tilt angle, type of solar panels, equipment (DC/AC inverter), a cable system as well as the way the design can be implemented in the electricity infrastructure of AAS. Power Quality (PQ) and the effects of implementing a SES will be discussed: disturbances have to be minimized

The accuracy and timing of pedestrian warnings at intersections: the acceptance from drivers and their preferences

Scipedia content — Mon, 08 Feb 2021 09:58:49 +0100

The safety of vulnerable road users at traffic intersections is critical. Driver assistance systems can improve safety but have to rely on accurate detection of hazardous situations. Given the complexity of pedestrian movement, detection of pedestrian presence and prediction of their behaviour are not always without error. Drivers' attitude towards such errors is an important issue for the effectiveness of the system. An online questionnaire survey has been carried out to investigate drivers' acceptance of the system under different reliability and accuracy configurations. The results show that safety warnings of pedestrians are generally found to be useful, although false positives and false negatives tend to reduce its pleasantness. The system is found to be most useful for right turn movement at a busy intersection, compared to through movements and quiet intersections. Drivers also find false alarms more acceptable than false negatives. In terms of timing of the warning message, drivers prefer to receive it earlier rather than later.

A mutualistic resource pooling architecture

Scipedia content — Mon, 08 Feb 2021 09:50:39 +0100

Parallelism pervades the Internet, yet efficiently pooling this increasing path diversity has remained elusive. We defend that the inability to progress beyond a single path paradigm is due to an inflexible resource sharing model, rather than a lack of routing solutions. The tussle between networks and hosts over resource sharing has constricted resource pooling into being redefined by stakeholders according to their own needs, often at the expense of others. In this paper we debate existing approaches to resource pooling and present PREFLEX, an architecture where edge networks and hosts both share the burden and reap the rewards of balancing traffic over multiple paths. Using PREF (Path RE-Feedback), networks suggest outbound paths to hosts, who in turn use LEX (Loss Exposure) to signal transport layer semantics such as loss and flow start to the underlying network. By making apparent network preferences and transport expectations, PREFLEX provides a mutualistic framework where congestion control and traffic engineering can both coexist and evolve independently.

Interaction Between Strategic and Local Traffic Flow Controls

Scipedia content — Wed, 03 Feb 2021 21:55:10 +0100

The loosely coordinated sets of traffic flow management initiatives that are operationally implemented at the national- and local-levels have the potential to under, over, and inconsistently control flights. This study is designed to explore these interactions through fast-time simulations with an emphasis on identifying inequitable situations in which flights receive multiple uncoordinated delays. Two operationally derived scenarios were considered in which flights arriving into the Dallas/Fort Worth International Airport were first controlled at the national-level, either with a Ground Delay Program or a playbook reroute. These flights were subsequently controlled at the local level. The Traffic Management Advisor assigned them arrival scheduling delays. For the Ground Delay Program scenarios, between 51% and 53% of all arrivals experience both pre-departure delays from the Ground Delay Program and arrival scheduling delays from the Traffic Management Advisor. Of the subset of flights that received multiple delays, between 5.7% and 6.4% of the internal departures were first assigned a pre-departure delay by the Ground Delay Program, followed by a second pre-departure delay as a result of the arrival scheduling. For the playbook reroute scenario, Dallas/Fort Worth International Airport arrivals were first assigned pre-departure reroutes based on the MW_2_DALLAS playbook plan, and were subsequently assigned arrival scheduling delays by the Traffic Management Advisor. Since the airport was operating well below capacity when the playbook reroute was in effect, only 7% of the arrivals were observed to receive both rerouting and arrival scheduling delays. Findings from these initial experiments confirm field observations that Ground Delay Programs operated in conjunction with arrival scheduling can result in inequitable situations in which flights receive multiple uncoordinated delays.

Analysis of stakeholder benefits of NextGen Trajectory-Based Operations

Scipedia content — Wed, 03 Feb 2021 21:41:54 +0100

Trajectory-Based Operations is a NextGen initiative that seeks to increase the effective-capacity of the National Airspace System by adding flexibility to the 4-D trajectories as flights traverse airspace.

Applications of Wireless Sensor Networks in the Oil, Gas and Resources Industries

Scipedia content — Wed, 03 Feb 2021 21:40:53 +0100

The paper provides a study on the use of Wireless Sensor Networks (WSNs) in refineries, petrochemicals, underwater development facilities, and oil and gas platforms. The work focuses on networks that monitor the production process, to either prevent or detect health and safety issues or to enhance production. WSN applications offer great opportunities for production optimization where the use of wired counterparts may prove to be prohibitive. They can be used to remotely monitor pipelines, natural gas leaks, corrosion, H2S, equipment condition, and real-time reservoir status. Data gathered by such devices enables new insights into plant operation and innovative solutions that aids the oil, gas and resources industries in improving platform safety, optimizing operations, preventing problems, tolerating errors, and reducing operating costs. In this paper, we survey a number of WSN applications in oil, gas and resources industry operations.

Predictability of Top of Descent Location for Operational Idle-Thrust Descents

Scipedia content — Wed, 03 Feb 2021 21:35:07 +0100

To enable arriving aircraft to fly optimized descents computed by the flight management system (FMS) in congested airspace, ground automation must accurately predict descent trajectories. To support development of the trajectory predictor and its uncertainty models, commercial flights executed idle-thrust descents at a specified descent speed, and the recorded data included the specified descent speed profile, aircraft weight, and the winds entered into the FMS as well as the radar data. The FMS computed the intended descent path assuming idle thrust after top of descent (TOD), and the controllers and pilots then endeavored to allow the FMS to fly the descent to the meter fix with minimal human intervention. The horizontal flight path, cruise and meter fix altitudes, and actual TOD location were extracted from the radar data. Using approximately 70 descents each in Boeing 757 and Airbus 319/320 aircraft, multiple regression estimated TOD location as a linear function of the available predictive factors. The cruise and meter fix altitudes, descent speed, and wind clearly improve goodness of fit. The aircraft weight improves fit for the Airbus descents but not for the B757. Except for a few statistical outliers, the residuals have absolute value less than 5 nmi. Thus, these predictive factors adequately explain the TOD location, which indicates the data do not include excessive noise.

On the rebound: how can we meet our carbon targets in light of rebound effects?

Scipedia content — Wed, 03 Feb 2021 21:25:45 +0100

Purpose of this paper is to estimate the rebound effects of innovative traffic management and public transport systems. This paper reviews what rebound effects are and how they apply to transport for technologies such as fuel efficient vehicles, telecommuting, e-commerce and fuel prices. We will identify innovations and best practice for sustainable transport strategies around the world, and make a wide ranging set of recommendations on how we can meet our carbon targets without falling short because of rebound effects.

ORTiC : A novel Approach towards Optimized Real Time CarPooling with an advanced Network Representation Model on siblings

Scipedia content — Wed, 03 Feb 2021 21:14:52 +0100

International audience; Thanks to the important and increasing growth of the Carpooling phenomenon throughout the world, many researchers have particularly focused their efforts on this concept. Researches led to many systems affording carpooling service. However, most of those systems present multiple drawbacks regarding automation, functionalities, accessibility, etc. In this paper, we focus on carpooling concept with an innovative view that tackle the problem of handling real time users requests. We aim at improving the quality of service so that subscribers could obtain a real time generated responses when needed. In order to deal with this problem, automatic tools are of compelling need. Furthermore, responses should be as efficient as possible with regards to the optimization criteria fixed up. In fact, there are two optimization sides in our system. It must not only perform different complex tasks within a reasonable runtime execution, but also provide responses that should meet users requirements in terms of trip duration and waiting time. Thus, we introduce a revolutionary system for Optimized Real Time Carpooling (ORTiC) based on a novel modeling of geographical areas served by carpooling vehicles. For this purpose, multiple techniques are required in order to optimize users requests processing. We especially consider the problem of constructing an adequate structure in order to set up an appropriate model which enables the system to provide a carpooling service in an optimized way (promptly and efficiently).

Effect of Dynamic Sector Boundary Changes on Air Traffic Controllers

Scipedia content — Wed, 03 Feb 2021 21:12:18 +0100

The effect of dynamic sector boundary changes on air traffic controller workload was investigated with data from a human-in-the-loop simulation. Multiple boundary changes were made during simulated operations, and controller rating of workload was recorded. Analysis of these data showed an increase of 16.9% in controller workload due to boundary changes. This increased workload was correlated with the number of aircraft handoffs and change in sector volume. There was also a 12.7% increase in average workload due to the changed sector design after boundary changes. This increase was correlated to traffic flow crossing points getting closer to sector boundaries and an increase in the number of flights with short dwell time in a sector. This study has identified some of the factors that affect controller workload when sector boundaries are changed, but more research is needed to better understand their relationships.

Sustainable mobility �C analysis of sustainable mobility measures in cities

Scipedia content — Wed, 03 Feb 2021 21:05:01 +0100

In interpersonal relationships, mobility is assumed as a sine qua non condition. It has been hazardous to the environment, the economy, and, consequently, society, to raise mobility dependence on the existing energy paradigm. The necessity to rethink all mobility paradigms and to develop more efficient and sustainable cities began in this context in order to address present societal needs without compromising future generations. In recent years, some of the most valuable tools used in this effort have been sustainable mobility plans, which have been adopted in several European cities. These plans are expected to be efficient ways to achieve relevant European goals, such as reduction of carbon dioxide emissions, one of the main causes of climate change. The authors illustrate state of the art sustainable mobility plans in three territories, designed to achieve more sustainable cities in the near future. The authors' main conclusions, in regard to achieving the goal of developing sustainable cities, are that there is an absence of a standard indicator for mobility measurement in cities, an important issue to address; it is necessary to use integrated push and pull measures in cities as a method to change people's behavior; and it is important to have a city network relating to best practices in mobility and urban planning.

A novel research on the relation between the number of passengers and the braking distance of a metro

Scipedia content — Wed, 03 Feb 2021 20:58:53 +0100

This paper on the relation between the number of passengers and the braking distance of a metro is from the proceedings of the 12th International Conference on Computer System Design and Operation in Railways and Other Transit Systems, held in Beijing, China, in 2010. The authors remind readers that, due to heavy traffic at peak times, it is necessary to ensure that trains have an absolute safety braking distance. To address this problem, the authors not only analyze various factors that influence a metro��s stopping time, but also analyze a time model of a metro��s stopping in the station. Based on the model and combined with the physical process of a metro��s approach, they calculate the braking distance of oncoming trains. Finally, a novel relation between the number of passengers and the braking distance of an oncoming metro is established. The authors conclude through their theoretical analysis and simulation experiments that the braking distance of an oncoming metro can be effectively calculated according to the number of passengers on the platform.

The Use of the Dynamic Solution Space to Assess Air Traffic Controller Workload

Scipedia content — Wed, 03 Feb 2021 20:57:59 +0100

traffic capacity is mainly bound by air traffic controller workload. In order to effectively find solutions for this problem, off-line pre-experimental workload assessment methods are desirable. In order to better understand the workload associated with air traffic control, previous research introduced the static Solution Space as a possible workload metric. The Solution Space Diagram is a mapping of intruding aircraft trajectories to the velocity/heading plane in the form of Conflict Zones and safe areas. Choosing a velocity vector in either one will provide an unsafe or a safe solution, respectively. In this paper an improved, dynamic Solution Space will be tested for correlations with air traffic controller workload, measured experimentally. A two dimensional experiment has been conducted, where subjects were required to line up all aircraft in a sector towards a certain waypoint, while continuously providing subjective workload ratings. High correlations were found between several Solution Space parameters and the subjective workload. Even though a conventional workload metric shows also to be highly correlated to the measured workload, the Solution Space could be the scenario independent workload metric that is currently missing in air traffic controller workload determination.

Probabilistic 4D trajectory prediction and conflict detection for air traffic control

Scipedia content — Wed, 03 Feb 2021 20:54:44 +0100

In this paper, we study the problem of aircraft 4D trajectory prediction and conflict detection which is one of the key functions of the Next Generation Air Transportation System (NextGen). A stochastic linear hybrid system (SLHS) with two different discrete state transition models is proposed to describe the aircraft motion. Based on the SLHS model, a 4D trajectory prediction algorithm is proposed utilizing some prior information about the aircraft's intent. Also, a computationally efficient conflict detection algorithm is developed based on the cumulative distribution function (cdf) approximation for the quadratic form of Gaussian random variables. The performance of the proposed algorithms is validated through an illustrative air traffic scenario.

Impact and management of stray current on DC rail systems

Scipedia content — Wed, 03 Feb 2021 20:51:34 +0100

The production of stray currents by DC transit systems can lead to the corrosion of nearby buried metallic structures, such as rail supporting structures, pipelines and cable sheaths. This paper describes the way in which stray current is produced by a DC transit system, measures that can be taken to mitigate the production and the impact it will have on the transit and surrounding infrastructure.

Observable dynamics and coordinate systems for automotive target tracking

Scipedia content — Wed, 03 Feb 2021 20:51:12 +0100

We investigate several coordinate systems and dynamical vector fields for target tracking to be used in driver assistance systems. We show how to express the discrete dynamics of maneuvering target vehicles in arbitrary coordinates starting from the target's and the own (ego) vehicle's assumed dynamical model in global coordinates. We clarify the notion of "ego compensation" and show how non-inertial effects are to be included when using a body-fixed coordinate system for target tracking. We finally compare the tracking error of different combinations of target tracking coordinates and dynamical vector fields for simulated data.

Comment: 6 pages, 3 figure

Real-Time Rendering of Dynamic Area and Volume Lights Using Hierarchical Irradiance Volumes

Scipedia content — Wed, 03 Feb 2021 20:51:02 +0100

Dynamic area and volume lights are a common phenomenon in our world. Examples include illuminated advertising, video screens, and lava lamps. Yet rendering such light sources in real-time in interactive scenes remains challenging. In this paper we present a method to render area or volume light sources in a fully dynamic scene, i.e. the geometry, materials, camera, and lights (spatial and spectral composition) can change continuously. The key idea of our approach is to decouple lighting from shading complexity by using a dynamically generated hierarchy of irradiance volumes as an intermediate approximation of incident lighting. The main contribution of this paper is a new computation scheme that updates irradiance volumes directly on the GPU and enables real-time performance. The algorithm is very fast, runs on DX9-level hardware, and is easy to integrate into existing rendering pipelines, which makes it well-suited for games and virtual-reality applications. Current limitations of our algorithm are that it cannot handle shadows and provides only a coarse approximation for glossy reflection.

Barcode-based calibration of a 1-D blur restoration pipeline

Scipedia content — Wed, 03 Feb 2021 20:46:49 +0100

In high-speed printed media inspection environments, image restoration pipelines play a critical role in establishing and continually evaluating performance. A key role of such systems is to understand, mitigate (and possibly remove) artifacts introduced by motion blur. An approach is proposed that uses barcodes to help calibrate a one-dimensional blur restoration pipeline. Techniques are demonstrated whereby the structure of barcode markings may be leveraged to estimate motion blur parameters, even under extreme blur conditions or when the barcode is unknown. In addition, a framework for comparing blur estimation procedures based on barcode readability is introduced. These techniques can be applied independently of one another, but together form a set of useful tools for blur restoration pipeline calibration. Within this framework, it is shown that a low-complexity blur estimation strategy demonstrates performance competitive with state-of-the-art approaches in term of speed and accuracy.

A Framework for Stochastic Air Traffic Flow Modeling and Analysis

Scipedia content — Wed, 03 Feb 2021 20:21:09 +0100

framework for stochastic traffic flow modeling over the U. S. National airspace based on queuing network models is advanced. The proposed framework allows the inclusion of a wide variety of trajectory uncertainties such as delays due to weather deviation, air traffic control actions, en route wind, aircraft performance, navigation system precision and flight control. En route queuing networks models are developed at origin-destination airport-level, Center-level, Sector-level and Latitude/Longitude-level spatial resolutions. Queuing models for the taxi, runway and TRACON flight segments have also been developed. Two approximations are employed to derive closed-form solutions to the queuing networks. Comparisons with Monte Carlo simulations and historic traffic data are used to validate the queuing network models. Validated queuing network models are then used to analyze a few next-generation air traffic operations concepts. The present research demonstrates that queuing network model solutions can closely approximate the Monte Carlo simulations, while delivering results at substantial savings in computational effort.

A Survey on Electric/Hybrid Vehicles

Scipedia content — Wed, 03 Feb 2021 20:16:11 +0100

Since the late 19th century until recently several electric vehicles have been designed, manufactured and used throughout the world. Some were just prototypes, others were concept cars, others were just special purpose vehicles and lately, a considerable number of general purpose cars has been produced and commercialized. Since the mid nineties the transportation sector emissions are being increasingly regulated and the dependency on oil and its price fluctuations originated an increasing interest on electric vehicles (EV). A wide research was made on existing electric/hybrid vehicle models. Some of these vehicles were just in the design phase, but most reached the prototype or full market production. They were divided into several types, such as NEVs, prototypes, concept cars, and full homologated production cars. For each type of vehicle model a technical historic analysis was made. Data related to the vehicle configuration as well as the embedded systems were collected and compared. Based on these data future prospect of evolution was subsequently made. The main focus was put on city vehicles and long range vehicles. For city vehicles the market approach normally consists in the use of full electric configuration while for the latter, the hybrid configuration is commonly used. The electrical systems and combustion engines found in these vehicles are compared in order to forecast the evolution trend in terms of specifications and performance of the whole vehicle and of each system. MIT Portugal, Funda??o para a Ci��ncia e a Tecnologia (FCT)