Scipedia: Documents published in 2008

Overcoming barriers to the implementation of alternative fuels for road transport in Europe

Scipedia content — Tue, 23 Mar 2021 04:22:50 +0100

The success of implementing alternative fuels for road transport depends on their cost, performance and reliability. This paper focuses on the use of natural gas and LPG, hydrogen and biofuels in Europe. A brief presentation is given of their technical development status, their market potential, and barriers to their implementation in various market segments. Some market barriers are common to many new technologies, and can be overcome through adequate policy measures at European level. Generally, a combination of policies is required, and a number of supporting measures increase their effectiveness. The following policies affecting energy use in transport are discussed: market incentives, policies targeting technology and vehicle efficiency, and overall system improvement.

Document type: Article

Options of biofuel trade from Central and Eastern to Western European countries

Scipedia content — Tue, 16 Feb 2021 13:20:06 +0100

Central and Eastern European countries (CEEC) have a substantial biomass production and export potential. The objective of this study is to assess whether the market for biofuels and trade can be profitable enough to realize a supply of biofuels from the CEEC to the European market and to estimate the cost performance of the energy carriers delivered. Five NUTS-2 (Nomenclature d'Unités Territoriales Statistiques) regions with high biomass production potentials in Poland, Romania, Hungary and the Czech Republic were analysed for biofuel export options. From these regions pellets from willow can be provided to destination areas in Western European countries (WEC) at costs of 105.2–219.8 € t−1. Ethanol can be provided at 11.95–20.89 € per GJ if the biomass conversion is performed at the destination areas in the WEC or at 14.84–17.83 € GJ−1J if the biomass to ethanol conversion takes place (at small scale) at the CEEC region where the biomass is produced. Short sea shipping shows most cost advantages for longer distance international transport compared to inland waterway shipping and railway. Another reason for lower biofuel supply costs are shorter distances between the regions of biomass production and the destination areas. Therefore the Szczecin region in Poland, closely located to the Baltic Sea, shows a better economic performance for long distance trade of biomass production than the selected region in Hungary (‘land-locked’). It is concluded that in future key CEEC regions can supply (pre-treated) biomass and biofuels to the European market at cost levels, which are sound and attractive to current and expected diesel and gasoline prices.

Traffic flow impacts of adaptive cruise control deactivation and (Re)activation with cooperative driver behavior

Scipedia content — Tue, 16 Feb 2021 13:12:00 +0100

In 2006 in the Netherlands, a field operational test was carried out to study the effect of adaptive cruise control (ACC) and lane departure warning on driver behavior and traffic flow in real traffic. To estimate the effect for larger penetration rates, simulations were needed. For a reliable impact assessment, the on- and off-switching of the system should be taken into account. Furthermore, because ACC systems are less cooperative than normal drivers, the reference behavior should include this cooperative behavior. In this research, cooperative driver models for normal drivers were developed as well as an ACC model that included on- and off-switching for the microscopic simulation environment known as the intelligent transportation systems modeler. Parameter settings were validated with data from the pilot. The results clearly show that on- and off-switching behavior has a large influence on traffic flow. This effect depends on the degree of congestion. In congestion, the effect of the ACC is larger. Without the possibility of switching it on and off, the ACC has a positive impact on throughput. However, when the ACC can be switched on and off, it has a negative impact on throughput.

Dynamic photonic lightpaths in the StarPlane network

Scipedia content — Tue, 16 Feb 2021 13:07:00 +0100

The StarPlane project enables users to dynamically control network photonic paths. Applications running on the Distributed ASCI Supercomputer (DAS-3) can manipulate wavelengths in the Dutch research and education network SURFnet6. The goal is to achieve fast switching times so that when the computational pattern in the computing clusters changes, the underlying network topology adapts rapidly to the new traffic flow. StarPlane develops: the software to perform optimal traffic engineering; the management plane to map the users’ request into directives for the network control plane, as well as the integration to the DAS-3 Grid middleware. We present here some preliminary results obtained with few selected Grid applications that make use of StarPlane.

GPS-based speed collection method for road traffic noise mapping

Scipedia content — Tue, 16 Feb 2021 13:05:58 +0100

One of the most difficult and expensive tasks in making noise pollution maps is the collection and processing of the data needed to create acoustic models. In the case of road traffic noise maps, obtaining speed data for light and heavy vehicles a problem that has usually been avoided by using a road's speed limit or by making assumptions based on experience from similar road types. Here global positioning systems-based techniques are applied for acquiring vehicle speed data and adapted to fulfill the requirements of noise prediction models. © 2009 Elsevier Ltd. All rights reserved.

A stochastic approach to traffic congestion costs

Scipedia content — Tue, 16 Feb 2021 13:05:45 +0100

The real world is a complex dynamic and stochastic environment. This is especially true for the traffic moving daily on our roads. As such, accurate modeling that correctly considers the real-world dynamics and the inherent stochasticity is very important, especially if government will base its road tax decisions on the outcomes of these models. The contemporary traffic prices, if any, however, do not reflect the external congestion costs. In order to induce road users to make the correct decision, marginal external costs should be internalized. To assess these costs, the public sector managers need accurate operational models. We show in this article that using a better representation and characterization of the road traffic, via stochastic queueing models, leads to a more adequate reflection of the congestion costs involved. Using extensive numerical experiments, we show the superiority of the stochastic traffic flow models.

P-cycle Protection in multi-domain optical networks

Scipedia content — Tue, 16 Feb 2021 13:04:49 +0100

Providing resilient inter-domain connections in multi-domain optical GMPLS networks is a challenge. On the one hand, the integration of different GMPLS domains to run traffic engineering operations requires the development of a framework for inter-domain routing and control of connections, while keeping the internal structure and available resources of the domains undisclosed to the other operators. On the other hand, the definition of mechanisms to take advantage of such automatically switched inter-domain connectivity is still an open issue. This article focuses on the analysis of applicability of one of these mechanisms: P-cycle-based protection. The proposed solution is based on the decomposition of the multi-domain resilience problem into two sub-problems, namely, the higher level inter-domain protection and the lower level intra-domain protection. Building a P-cycle at the higher level is accomplished by certain tasks at the lower level, including straddling link connection, capacity allocation and path selection. In this article, we present several methods to realize inter-domain P-cycle protection at both levels and we evaluate their performance in terms of availability and spent resources. A discussion on a proposal of implementation of signalling based on extensions of existing protocols such as RSVP-TE and the PCE architecture illustrates the practical viability of the approach.

Ultra low emission vehicle development: a study on the drivers for car firms and the implications for sustainable development policy

Scipedia content — Tue, 16 Feb 2021 12:54:13 +0100

This paper studies the factors that lead automotive manufacturing firms to invest in Ultra Low Emission Vehicles (ULEVs). ULEVs are vehicles that emit extremely low levels of harmful gases compared to other vehicles. In contrast to studies that examine aggregated patterns on the market (such as sales levels, new launches and issued patents), this study 'moves into the mind' of individual car firms following a social-psychological approach to identify the barriers and drivers. As an example of a ULEV, we report on the drivers and barriers for car manufacturers around the development of hydrogen engine technology. The study reveals that different firms deal differently with hydrogen vehicle development. Broadly, three groups of firms were distinguished concerning their willingness to invest in ULEV: uncertain firms, unwilling firms and optimistic firms. It addition, it was found that the level of technological and organisational capabilities is highly correlated to the willingness of firms to engage in hydrogen technology development. Based on an integrated sustainability assessment that takes into account technological opportunities, business perceptions and policy options, we argue that current policy should strongly focus on supporting R&D capability in manufacturing firms. © 2009 Inderscience Enterprises Ltd.

The study of traffic hotspot air quality and street scale modelling in the Street Emission Ceilings (SEC) Project

Scipedia content — Tue, 16 Feb 2021 12:51:54 +0100

The introduction of local scale analysis in Integrated Assessment Modelling (IAM) requires an evaluation of road transport emission factors and local scale air quality models. The comparison of PM10 and PM2.5 over NOx delta (street level minus background) concentration ratios against emission ratio estimates, confirms the appropriateness of the COPERT methodology. The comparison also reveals the non-exhaust coarse fraction source in Stockholm to be three times the fine fraction in summer, but seven times that in winter. In London it is twice the fine fraction. The model intercomparison study shows that simple street canyon models can be sufficient for use in IAM. Copyright © 2009, Inderscience Publishers.

Drivers' reactions to sudden braking by lead car under varying workload conditions; towards a driver support system

Scipedia content — Tue, 16 Feb 2021 12:43:18 +0100

urban intersections drivers handle multiple tasks simultaneously, making urban driving a complex task. An advanced driver assistance system may support drivers in this specific driving task, but the design details of such a system need to be determined before they can be fully deployed. A driving simulator experiment was conducted to determine the relationship between different subtasks of driving at urban intersections. Participants completed four drives, each comprising 20 comparable intersections with different traffic situations and encountered one unexpected braking event during the experiment. The effects of varying levels of event urgency on the relationship between different driving subtasks were studied. Furthermore, the influence of workload on this relationship was determined by giving half of the subjects an additional cognitive task. After the lead car braked unexpectedly, participants reduced speed and increased headway depending on the urgency of the braking event. Depending on the workload, participants returned to the normal speed and headway again after a number of intersections. Participants experiencing a high-workload drove more smoothly, except for those who had experienced the most urgent unexpected event. High workload additionally affected the length of the adjustments to the unexpected event.

A knowledge‐based conflict resolution tool for en‐route air traffic controllers

Scipedia content — Tue, 16 Feb 2021 12:41:53 +0100

WOS: 000261774600007

Purpose - The purpose of this paper is to develop a knowledge-based decision support tool used for assisting en-route air traffic controllers by generating resolutions for dual aircraft conflicts after being integrated into a model-based conflict detection and conflict resolution system. Design/methodology/approach - Air traffic controller knowledge, which was obtained from the literature research, about solving aircraft conflicts is represented in a decision tree. Then it is written in Visual Basic programming language. With reference to several rules form the expert air traffic controller knowledge and some factors which affect controller conflict resolution process, the tool generates advisories consisting of eight kinds of separation strategies. Findings - The paper finds that it is expected to increase the safety of air traffic system by supporting air traffic controller in conflict resolution process. Controller workload can be reduced by fast, reliable and acceptable resolution advisories of the tool. Research limitations/implications - The accuracy of decision tree is limited with the adequacy and quality of knowledge obtained from references, several assumptions and interpretation. Because of the unavailability of a model-based conflict detection and resolution tool, the tool could not be evaluated in simulations. Originality/value - After being integrated into a model-based decision support tool, it can reduce the deficiencies of the model-based tool such as low degree of resolution acceptance by controllers and low-resolution speed by providing expert air traffic controller knowledge to the tool.

INVESTIGATING URBAN TRAFFIC BASED NOISE POLLUTION IN THE CITY OF KIRIKKALE, TURKEY

Scipedia content — Tue, 16 Feb 2021 12:41:13 +0100

The study presents an investigation into traffic based noise pollution in the city of Kirikkale, Turkey. For this purpose, traffic noise levels were measured at 15 intersections across the city during three peak times ‐ morning (08:00–09:00), noon (12:30–13:30) and evening (17:00–18:00) hours. The comparison of Leq values against the limit values of the Turkish Noise and Control Regulations for Settlement Zones showed that Leqvalues exceeded the limits at all stations. A linear regression analysis performed between the Leq and logarithm of total traffic volume (log Q) produced a coefficient of determination of 0.52. A multi regression analysis carried out between the Leq and four different vehicle types resulted in a correlation coefficient of 0.74. The correlation matrix indicated that the highest correlation was found for trucks/buses with r = 0.92. The spatial maps of traffic noise created by the Kriging method under ArcView GIS displayed that there seemed to be significant differences in the spatial variation of traffic noise across the city. In order to reduce traffic based noise levels within the city some useful suggestions were presented. First published online: 27 Oct 2010

Adaptive interfaces in driving

Scipedia content — Tue, 16 Feb 2021 12:31:00 +0100

The automotive domain is an excellent domain for investigating augmented cognition methods, and one of the domains that can provide the applications. We developed, applied and tested indirect (or derived) measures to estimate driver state risks, validated by direct state-sensing methods, with major European vehicle manufacturers, suppliers and research institutes in the project AIDE (Adaptive Integrated Driver-vehicle InterfacE). The project developed an interface with the driver that integrates different advanced driver assistant systems and in-vehicle information systems and adapted the interface to different driver or traffic conditions. This paper presents an overview of the AIDE project and will then focus on the adaptation aspect of AIDE. Information presented to the driver could be adapted on basis of environmental conditions (weather and traffic), and on basis of assessed workload, distraction, and physical condition of the driver. The adaptation of how information is presented to the driver or the timing of when information is presented to the driver is of importance. Adapting information, however, also results in systems that are less transparent to the driver. Â© 2009 Springer.

Numerical study of heat transfer from an offshore buried pipeline under steady–periodic thermal boundary conditions

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

The steady-periodic heat transfer between offshore buried pipelines for the transport of hydrocarbons and their environment is investigated. This heat transfer regime occurs for shallow water buried pipelines, as a consequence of the temperature changes of the seabed during the year. First, the unsteady two dimensional conduction problem is written in a dimensionless form; then, it is transformed into a steady two dimensional problem and solved numerically by means of the finite–element software package Comsol Multiphysics (© Comsol, Inc.). Several values of the burying depth and of the radius of the pipeline, as well as of the thermal properties of the soil are considered. The numerical results are compared with those obtainable by means of an approximate method employed in industrial design. The comparison reveals that important discrepancies with respect to this approximate method may occur.

Mega Events and Mobility: the impacts on the quality of the urban environment

Scipedia content — Tue, 16 Feb 2021 12:22:36 +0100

Il contributo esamina i principali impatti sulla qualità dell’ambiente urbano connessi ai “Grandi Eventi” e, in particolare, ai “Giochi Olimpici”. Nell’ambito dell’organizzazione di tali eventi, che inevitabilmente comportano rilevanti trasformazioni infrastrutturali nelle città che li ospitano, già da alcuni anni il tema della sostenibilità dei progetti e delle realizzazioni ha assunto un peso rilevante. Nell’ultimo decennio numerosi sono stati gli sforzi compiuti dal Comitato Olimpico Internazionale per assicurare che alle città ospiti sia consegnata una positiva eredità di lungo periodo e, soprattutto, per delineare criteri e linee guida volte ad improntare a criteri di sostenibilità l’organizzazione dei Giochi Olimpici. È evidente che il rischio connesso all’uso strumentale di espressioni come Green Olympics o Sustainable Olympics è piuttosto rilevante ed è a tal fine che in questa sede si esamina  attraverso il confronto tra città che hanno ospitato e/o che si apprestano ad ospitare i Giochi e qual è il peso assunto dalle strategie di intervento volte a promuovere una mobilità urbana sostenibile e quali sono gli esiti, reali o presunti, in termini di duraturi miglioramenti della qualità dell’ambiente urbano. Come è noto, infatti, la mobilità urbana, ancora dominata dal trasporto privato su gomma, costituisce uno dei principali detrattori di qualità dell’ambiente urbano, una delle principali cause di “insostenibilità” su cui, già da alcuni anni, sono concentrate strategie, iniziative e progetti di ricerca dell’Unione Europea. Pertanto, sulla base del confronto tra le scelte effettuate e/o previste in alcune città olimpiche, il contributo delinea alcuni indirizzi mirati a ri-orientare gli investimenti infrastrutturali in occasione dei Grandi Eventi verso il perseguimento di una mobilità urbana sostenibile.

Improved road traffic emission inventories by adding mean speed distributions

Scipedia content — Tue, 16 Feb 2021 12:10:39 +0100

Does consideration of average speed distributions on roads-as compared to single mean speed-lead to different results in emission modelling of large road networks? To address this question, a post-processing method is developed to predict mean speed distributions using available traffic data from a dynamic macroscopic traffic model (Indy) that was run for an actual test network (Amsterdam). Two emission models are compared: a continuous (COPERT IV) and a discrete model (VERSIT+macro). Computations show that total network emissions of CO, HC, NOx, PM10 and CO2 are generally (but not always) increased after application of the mean speed distribution method up to +9%, and even up to +24% at sub-network level (urban, rural, motorway). Conventional computation methods thus appear to produce biased results (underestimation). The magnitude and direction of the effect is a function of emission model (type), shape of the composite emission factor curve and change in the joint distribution of (sub)-network VKT (vehicle kilometres travelled) and speed. Differences between the two emission models in predicted total network emissions are generally larger, which indicates that other issues (e.g., emission model validation, model choice) are more relevant. © 2007 Elsevier Ltd. All rights reserved.

Driving with a congestion assistant

Scipedia content — Tue, 16 Feb 2021 12:10:07 +0100

New driver support systems are developed and introduced to the market at increasing speed. In conditions of traffic congestion drivers may be supported by a “Congestion Assistant”, a system that combines the features of a Congestion Warning System (acoustic warning and gas pedal counterforce) and a Stop & Go system (automatic gas and brake pedal during congestion). To gain understanding of the effects of driving with a Congestion Assistant on drivers, mental workload of drivers was registered under different conditions as well as acceptance of the system. Mental workload was measured by means of physiological registrations, i.e. heart rate, a secondary task and with the aid of subjective scaling techniques. Acceptance was measured with an acceptance scale. The study was carried out in an advanced driving simulator. Driving with the Congestion Assistant while in congestion potentially leads to decreased driver mental workload, whereas just before congestion starts, i.e. developing just noticeable, the system may add to the workload of the driver. Acceptance is generally high after experiencing the system, though not in all respects.

Pedestrian routes and urban requalification: the Montesanto area in Naples

Scipedia content — Tue, 16 Feb 2021 12:09:52 +0100

Il contributo illustra una proposta progettuale per la riqualificazione di un’area del centro storico di Napoli attraverso la realizzazione di una rete di percorsi a prevalente fruizione pedonale. L’area di studio, il nucleo di Montesanto, è attualmente sede di rilevanti attrezzature urbane e si caratterizza quale nodo primario del trasporto urbano su ferro, punto di smistamento di rilevanti flussi di utenza sia verso il nucleo della città greco-romana sia verso l’area direzionale e il centro monumentale. La proposta progettuale – che si inquadra in un più ampio Piano per la Mobilità Pedonale Protetta nella città storica di Napoli - è volta a favorire la coesistenza, in condizioni di sicurezza, tra flussi pedonali ad elevata intensità e flussi automobilistici (utenza locale e accessibilità di emergenza), oltre che garantire l’innesco di un processo di riqualificazione che, a partire dagli archi e dai nodi della rete pedonale, investa l’area nel suo complesso. Più specificamente, a partire da una approfondita analisi delle caratteristiche di contesto e delle peculiarità dei singoli assi e nodi della rete viaria, la proposta fornisce indirizzi progettuali per la riorganizzazione delle attività e dei flussi lungo la rete viaria e per la conseguente ridefinizione delle caratteristiche spaziali degli elementi inclusi nella rete a prevalente fruizione pedonale.

Battery energy storage system

Scipedia content — Tue, 16 Feb 2021 12:09:01 +0100

The ability to store electrical energy adds several interesting features to a ships distribution network, as silent power, peak shaving and a ride through in case of generator failure. Modern intrinsically safe Li-ion batteries bring these within reach. For this modern lithium battery applications thermal management is vital in achieving a good trade off between maximum lifetime and optimal performance. This article addresses part of the thermal design of a battery storage system, based on commercially available lithium battery technology. During the design process the model assisted in assessment of design choices by checking that battery temperature rise would remain within acceptable levels. The final design is based on eight modules in parallel called PowerBlocks, where each module consists of thirty lithium batteries in series (30×12.8V = 384V; 130Ah) and a three phase converter. The complete battery storage system was modeled thermally, where validation of the model was done in the laboratory. Based on the experimental results from the validation a safe operating area was defined, which marks the thermal boundaries of the system. This study's conclusions indicate that commercially available lithium battery technology can, with good thermal management, be applied to improve the performance of power distribution systems in maritime applications.

Position control of a wheeled mobile robot including tire behavior

Scipedia content — Tue, 16 Feb 2021 12:05:42 +0100

dvanced driver assistance systems are increasingly available on road vehicles. These systems require a thorough development procedure, an important part of which consists of hardware-in-the-loop experiments in a controlled environment. To this end, a facility called Vehicle Hardware-In-the-Loop (VeHIL) is operated, aiming at testing the entire road vehicle in an artificial environment. In VeHIL, the test vehicle is placed on a roller bench, whereas other traffic participants, i.e., vehicles in the direct neighborhood of the test vehicle, are simulated using wheeled mobile robots (WMRs). To achieve a high degree of experiment reproducibility, focus is put on the design of an accurate position control system for the robots. Due to the required types of maneuvers, these robots have independently driven and steered wheels. Consequently, the robot is overactuated. Furthermore, since the robot is capable of high-dynamic maneuvers, slip effects caused by the tires can play an important role. A position controller based on feedback linearization is presented, using the so-called multicycle approach, which regards the robot as a set of identical unicycles. As a result, the WMR is position controlled, whereas each unicycle is controlled, taking weight transfer and longitudinal and lateral tire slip into account. © 2006 IEEE.

Effects of road transport on yearling lambs up to 19 hours

Scipedia content — Tue, 16 Feb 2021 12:02:08 +0100

Summary: This study was performed to determine the weight losses, subsequent recovery rate and transportation costs of yearling lambs transported for 3, 6, 9 and 19 hours. In this research, total 63 shorn, male, yearling Akkaraman lambs were weighed to equal the initial live weights and assigned into 4 groups, namely group I (transported 3 hours), group II (transported 6 hours), group III (transported 9 hours+1 hour resting+9 hours) and control group (untransported). Transported lambs were loaded on the lorry at a density of 0.35 m 2 /head while the control group (untransported) was kept at the same density on the farm. The lambs transported for 3, 6 and 9 hours lost more live weight than the lambs in control group (p"0.05). Compared to control group, significant increases were determined in the percentage of the live weight losses in transported lambs with the increasing journey duration. The cost due to net weight loss for 9 hours transportation was higher than the other groups. Consequently, although point of animal welfare view, transportation of slaughtering animals should be for short time, if marketing conditions entail long time transportation, lambs should be rested for feeding and watering during transportation for rapid recovery rate and reducing the cost of net weight losses. Key words: Recovery, transportation cost, weight loss, yearling lamb.

Scheduling aircraft landings using airlines’ preferences

Scipedia content — Tue, 16 Feb 2021 11:52:00 +0100

val runways are a critical resource in the air traffic system. Arrival delays have a great impact on airline operations and cost. Therefore, tactical arrival planning is becoming increasingly important. In this paper, we consider the tactical single runway arrival problem. The current focus on collaborative decision making is reflected by giving airlines the possibility to provide cost functions related to arrival delays for their flights. A scaling method for these cost is introduced to ensure equity. Our formulation will assign landing times to the flights, while taking the costs into account. A problem-specific local search heuristic has been implemented to obtain reasonable solutions within acceptable computation times. A large number of instances, created using schedule data from a major European hub, have been tested. These experiments show large cost savings for the airlines compared to current practice. All airlines achieve improvements, which is important for the acceptance of the method. The heuristic is able to solve instances with over 100 flights in a few minutes. A simulation experiment shows the method can also be used in a dynamic setting and produces robust schedules. © 2007 Elsevier B.V. All rights reserved.

A spectral-geophysical approach for detecting pipeline leakage

Scipedia content — Tue, 16 Feb 2021 11:38:52 +0100

Leakage of hydrocarbon has a large economic and environmental impact. Traditional methods for investigating leakage and resulting pollution, such as drilling, are destructive, time consuming and expensive. Remote sensing is an alternative that is non-destructive and has been been tested extensively for exploration of onshore hydrocarbon reservoirs and detection of hydrocarbons at the Earth’s surface. In this research, a leaking pipeline is investigated through field reflectance spectrometry and the findings are validated with traditional drilling and geophysical measurements. The measurements show a significant increase of vegetation anomalies on the pipeline with respect to areas further away. The observed anomalies are positively related to hydrocarbon pollution through chemical analysis of drillings. Subsurface geophysical measurements show a large correlation with observed surface vegetation stress, enhancing the identification of hydrocarbon-related vegetation stress through spectroscopy.

From Design to Application of a Decision-support System for Integrated River-basin Management

Scipedia content — Tue, 16 Feb 2021 11:29:49 +0100

During the last two decades several integrated tools have been developed to make the existing scientific knowledge available to river managers and assist them with the formulation and evaluation of alternative combinations of measures. Yet, few practical examples of embedding of these instruments in river management organizations can be observed so far. This paper identifies the possible organizational, technical, and scientific factors that may form an obstacle for the design and application of a Decision-Support System (DSS) for river-basin management by analyzing the interaction between the different participants in the Elbe DSS project. In particular attention is paid to the software engineering aspects of the design process. In order to start an integrated approach to deal with conflicting river strategies a project to develop a prototype tool for integrated management of the Elbe catchment was initiated, which includes functionalities related to inland navigation, water quality, flood safety, and vegetation ecology. The problems faced in the German part of the Elbe catchment range from poor navigation conditions and flooding vulnerability to a need to restore and maintain the natural state of the floodplains. Several river engineering works such as large-scale dike shifting, channel dredging, and large-scale retention are in a planning or implementation stage. From the beginning of the project onwards attention was paid to the involvement of potential end-users and key stakeholders in the design process. The experience of the project is that internal consistency of models and data, effective communication, and functional flexibility are essential to warrant a proper balance between scientific standards, the availability of models, and the requirements of users. This facilitates the design process and improves the chance of successful implementation.

Vehicle routing with dynamic travel times: a queueing approach

Scipedia content — Tue, 16 Feb 2021 11:24:51 +0100

International audience; Transportation is an important component of supply chain competitiveness since it plays a major role in the inbound, inter-facility, and outbound logistics. In this context, assigning and scheduling vehicle routes is a crucial management problem. In this paper, a vehicle routing problem with dynamic travel times due to potential traffic congestion is considered. The approach developed introduces mainly the traffic congestion component based on queueing theory. This is an innovative modeling scheme to capture travel times. The queueing approach is compared with other approaches and its potential benefits are described and quantified. Moreover, the optimization of the starting times of a route at the distribution center is evaluated. Finally, the trade-off between solution quality and calculation time is discussed. Numerous test instances are used, both to illustrate the appropriateness of the approach as well as to show that time-independent solutions are often unrealistic within a congested traffic environment, which is usually the case on European road networks.

Pricing, capacity and long-run cost functions for first-best and second-best network problems

Scipedia content — Tue, 16 Feb 2021 11:21:57 +0100

This paper considers the use of 'long-run cost functions' for congested networks in solving second-best network problems, in which capacity and tolls are instruments. We derive analytical results both for general cost and demand functions and for specific functional forms, namely Bureau of Public Roads cost functions and constant-elasticity demand functions. The latter are also used in a numerical simulation model. We consider second-best cases where only a sub-set of links in a network is subject to tolling and/or capacity choice, and cases with and without a self-financing constraint imposed. We will demonstrate that, under certain assumptions, second-best long-run cost (or actually: generalized price) functions can be derived for most of the cases of interest, which can be used in an applied network model as a substitute for the conventional short-run user cost functions. Doing so reduces the dimensionality of the problem and should therefore be helpful in speeding up procedures for finding second-best optima. © 2009 Elsevier Ltd.

AV e attività di eccellenza. Nuove opportunità localizzative nel sistema Roma-Napoli

Scipedia content — Tue, 16 Feb 2021 11:17:30 +0100

Il contributo propone una lettura delle possibili influenze della realizzazione delle reti AV sulla localizzazione/distribuzione di attività di eccellenza, quali attività direzionali, di management, di servizio alle imprese e alla pubblica amministrazione, con specifico riferimento alla tratta AV Roma-Napoli. A partire da una caratterizzazione delle attività di eccellenza, se ne evidenzia anzitutto la spiccata tendenza alla concentrazione urbana, la dipendenza da efficaci connessioni sia immateriali che materiali e la rilevanza assunta dalla variabile temporale nelle scelte localizzative (Sassen, 2001). Quindi, in riferimento ad alcune esperienze europee, si esaminano i principali effetti, in termini di attrazione/concentrazione di tali attività, connessi alla realizzazione delle reti AV (Sands 1993; Vickerman e Ulied, 2006; Gemeente Amsterdam, 2007). Sulla base di tali considerazioni e tenendo conto delle più recenti definizioni e metodi di misura dell’accessibilità (Axhausen et al. 2006; Spiekermann, Wegener, 2005), lo studio propone un indicatore di “accessibilità” finalizzato ad individuare e graduare, in ragione dei livelli di accessibilità, un sistema di luoghi urbani interconnessi mediante reti su ferro (AV e reti metropolitane e regionali) dai quali le attività di eccellenza potranno massimizzare il proprio bacino di utenza. L’individuazione di un sistema di luoghi urbani a diverso grado di accessibilità consente di evidenziare le numerose opportunità per la localizzazione di attività di eccellenza che si dischiudono a seguito della riduzione dei tempi di spostamento consentita dalle reti AV. In tal senso, l’indicatore proposto può costituire un utile supporto alle decisioni sia per l’attore pubblico consentendo di governare e orientare i processi di trasformazione conseguenti alla realizzazione della rete AV, estendendone i benefici dalle aree di stazione a più ampie porzioni urbane sia per l’investitore privato, al fine di identificare le localizzazioni ottimali per disporre di un mercato di riferimento il più possibile esteso. Più specificamente, l’indicatore di accessibilità è stato definito in riferimento alla realizzazione della rete AV che collegherà Roma e Napoli in un tempo di 55 minuti. Pertanto, il sistema di aree per la localizzazione delle attività di eccellenza in ciascuna delle due polarità urbane considerate viene individuato ipotizzando un tempo massimo di percorrenza tra i due sistemi urbani pari a 90 minuti. Tale intervallo temporale si ritiene accettabile per il tipo di spostamenti connessi alle attività in esame: non si tratta, infatti, di spostamenti pendolari quanto, piuttosto, di una mobilità connessa alla fornitura di servizi altamente specializzati. Come ben evidenziato in una recente rassegna sul termine accessibilità, il tempo che si è disposti ad impiegare per raggiungere una data destinazione è, infatti, funzione del tipo di utenza e del tipo di attività o, più in generale, della convenienza per un dato individuo o per una data impresa (Litman, 2007). L’indicatore proposto tiene conto, oltre che del tempo di spostamento calcolato sulla rete su ferro sia nella tratta AV di connessione tra i due centri che nella tratta urbana della qualità del viaggio, considerando il numero e il tipo di scambi che è possibile effettuare sulla rete urbana, nell’arco temporale definito. L’applicazione dell’indicatore al sistema urbano integrato Roma-Napoli ha consentito l’individuazione, nelle due polarità urbane, di aree a diverso grado di “accessibilità” a partire dai due punti focali posti nelle stazioni AV e nell’arco temporale individuato e, conseguentemente, delle aree che, in ragione del solo parametro di accessibilità, risultano le più idonee per la localizzazione delle attività in esame.

Neuro-fuzzy approach in estimating Hazen-Williams friction coefficient for small-diameter polyethylene pipes

Scipedia content — Tue, 16 Feb 2021 10:51:24 +0100

WOS: 000266339000006

Low-pressurized multiple outlet pipelines are extensively used to uniformly distribute irrigation water under different types of low-volume micro-irrigation systems. Polyethylene (PE) is the main pipe material for smooth pipes in sub-main unit of a micro-irrigation system due to its flexibility and resistibility to the sun. For computing friction loss in PE pipes, many practicing engineers hesitate to use the generalized Darcy-Weisbach equation since the friction coefficient varies at each section of the lateral. Although its non-dimensional homogeneity and limitations in applicability, the empirical Hazen-Williams equation is still commonly preferred, because of its simplicity in practice. In the current hydraulic computations for friction loss, some typical fixed values for the Hazen-Williams coefficient (C(HW)) in PE pipes are still recommended regardless of pipe diameter. Experimental works have confirmed that there is a strong dependence of the C(HW) on pipe diameter (D), therefore a single value of the C(HW) cannot be used for all ranges of pipe diameters. The primary focus of this research is to investigate the accuracy of a fuzzy rule system approach to estimate the proper value of the C(HW) coefficient for different pipe diameters because of the imprecise, insufficient, ambiguous and uncertain data available. A neuro-fuzzy approach was developed to relate the input (flow rate and pipe diameter) and output (C(HW) and friction loss) variables. The application of the proposed approach was performed using the measured data for friction losses available from the recent experimental analysis, hence its performance was tested using some statistic parameters for error estimation. The examination results indicated that through fuzzy rules and membership functions the proposed model can be successfully used to identify the proper values of C(HW) coefficient hence accurately estimate friction losses through smooth PE pipes. (C) 2008 Elsevier Ltd. All rights reserved.

A nonlinear, recurrence-based approach to traffic classification

Scipedia content — Tue, 16 Feb 2021 10:27:35 +0100

The ability to accurately classify and identify the network traffic associated with different applications is a central issue for many network operation and research topics including Quality of Service enforcement, traffic engineering, security, monitoring and intrusion-detection. However, traditional classification approaches for traffic to higher-level application mapping, such as those based on port or payload analysis, are highly inaccurate for many emerging applications and hence useless in actual networks. This paper presents a recurrence plot-based traffic classification approach based on the analysis of non-stationary "hidden" transition patterns of IP traffic flows. Such nonlinear properties cannot be affected by payload encryption or dynamic port change and hence cannot be easily masqueraded. In performing a quantitative assessment of the above transition patterns, we used recurrence quantification analysis, a nonlinear technique widely used in many fields of science to discover the time correlations and the hidden dynamics of statistical time series. Our model proved to be effective for providing a deterministic interpretation of recurrence patterns derived by complex protocol dynamics in end-to-end traffic flows, and hence for developing qualitative and quantitative observations that can be reliably used in traffic classification. Â© 2008 Elsevier B.V. All rights reserved.

Store Buffer Design for Multibanked Data Caches

Scipedia content — Tue, 16 Feb 2021 10:26:29 +0100

This paper focuses on how to design a store buffer (STB) well suited to first-level multibanked data caches. The goal is to forward data from in-flight stores into dependent loads within the latency of a cache bank. Taking into account the store lifetime in the processor pipeline and the data forwarding behavior, we propose a particular two-level STB design in which forwarding is done speculatively from a distributed first-level STB made of extremely small banks, whereas a centralized, second-level STB enforces correct store-load ordering. Besides, the two-level STB admits two simplifications that leave performance almost unchanged. Regarding the second-level STB, we suggest to remove its data forwarding capability, while for the first-level STB, it is possible to: 1) remove the instruction age checking and 2) compare only the less significant address bits. Experimentation covers both integer and floating point codes executing in dynamically scheduled processors. Following our guidelines and running SPEC-2K over an 8-way processor, a two-level STB with four 8-entry banks in the first level performs similar to an ideal, single-level STB with 128-entry banks working at the first-level cache latency. Also, we show that the proposed two-level design is suitable for a memory-latency-tolerant processor.

Development of a driver information and warning system with vehicle hardware-in-the-loop simulations

Scipedia content — Tue, 16 Feb 2021 10:25:26 +0100

This paper presents a new method for the design and validation of advanced driver assistance systems (ADASs). With vehicle hardware-in-the-loop (VeHIL) simulations the development process, and more specifically the validation phase, of intelligent vehicles is carried out safer, cheaper, and more manageable. In the VeHIL laboratory a full-scale ADAS-equipped vehicle is set up in a hardware-in-the-loop simulation environment, where a chassis dynamometer is used to emulate the road interaction and where robot vehicles are used to represent other traffic. In this controlled environment the performance and dependability of an ADAS is tested to great accuracy and reliability. The working principle and the added value of VeHIL are demonstrated with test results of a driver information and warning system. Based on the 'V' diagram, the position of VeHIL in the development process of ADASs is illustrated. © 2009 Elsevier Ltd. All rights reserved.

The worst-case execution-time problem—overview of methods and survey of tools

Scipedia content — Tue, 16 Feb 2021 10:12:56 +0100

The determination of upper bounds on execution times, commonly called worst-case execution times (WCETs), is a necessary step in the development and validation process for hard real-time systems. This problem is hard if the underlying processor architecture has components, such as caches, pipelines, branch prediction, and other speculative components. This article describes different approaches to this problem and surveys several commercially available tools1 and research prototypes.

Mobilità dolce e reti pedonali in città

Scipedia content — Tue, 16 Feb 2021 09:54:47 +0100

In riferimento alle più ampie strategie messe in campo nelle città europee fin dalla metà degli anni Novanta per l’incentivazione di forme di mobilità “sostenibile” nei contesti urbani e al più recente concetto di mobilità dolce, essenzialmente riferibile alla mobilità pedonale e ciclabile, questo contributo affronta specificamente il tema della mobilità pedonale in ambito urbano, delineando criteri ed elementi di metodo per l’individuazione e il progetto d’uso di reti di spazi aperti urbani, quali strade e piazze, ad esclusiva o prevalente fruizione pedonale. Anzitutto, si enfatizza la molteplicità di ruoli che gli spazi aperti urbani quali strade e piazze rivestono all’interno della città: assi di supporto ai flussi di mobilità, anche pedonali, ma soprattutto luoghi urbani, immersi in specifici contesti, e chiamati a supportare un’eterogenea gamma di attività (dal commercio all’incontro, al gioco dei bambini). Sulla base di tali considerazioni, vengono individuate le principali ragioni per l’organizzazione in rete degli spazi aperti urbani destinati alla fruizione pedonale e vengono descritti, anche attraverso casi esemplificativi, alcuni approcci correnti alla progettazione di reti pedonali. Quindi, vengono delineati i principali elementi di metodo sia per l’individuazione delle reti che per il progetto d’uso dei singoli elementi, con particolare attenzione agli elementi di raccordo tra la rete e il contesto urbano, alle peculiarità connesse alla localizzazione della rete in aree urbane centrali o periferiche, alla rispondenza tra usi e caratteristiche spaziali degli elementi della rete. Anche se gli indirizzi di metodo proposti sono stati oggetto di numerose sperimentazioni in aree centrali e periferiche della città di Napoli, essi sono da intendersi quale primo passo verso la messa a punto di un metodo di lavoro consolidato per l’organizzazione e il progetto di reti pedonali in ambito urbano.

Lead emissions from road transport in Europe. A revision of current estimates using various estimation methodologies

Scipedia content — Tue, 16 Feb 2021 09:53:50 +0100

Large-scale use of leaded gasoline was an important source of the neurotoxin lead in the European environment. After a sequence of regulations on the allowed gasoline lead content and, eventually, a ban on the use of lead additives in gasoline, road transport was no longer considered a source of atmospheric lead. Currently a discrepancy exists between measured atmospheric lead concentrations and model-predicted concentrations, suggesting that lead emissions to the atmosphere may be underestimated. Recently it was suggested that lead emission from unleaded gasoline combustion is still an important source and may (partly) fill the gap between modelled and observed atmospheric lead concentrations. In this paper we assess the plausibility of the latter suggestion by following various emission estimation methodologies. The uncertainty of lead emissions from road transport is further reduced by chemical analysis of fuel samples. The result of our assessment is that lead from road transport fuel combustion is not the missing lead source needed to fill the gap between modelled and observed lead concentrations. Road transport is still a source of lead through brake wear and a small contribution from exhaust emissions but this contributes no more than 5-8% of the EU25 total emission. © 2009 Elsevier B.V. All rights reserved.

MEASURING UNCERTAINTY IN LONG-TERM TRAVEL DEMAND FORECASTING FROM DEMOGRAPHIC MODELLING

Scipedia content — Fri, 12 Feb 2021 16:03:37 +0100

Uncertainty on traffic forecasts may have an impact on reimbursement scheduling for investment, as well as for scenarios for operating costs. Even the best projections are based on models and assumptions, thus raising the question of their accuracy. Indeed, long term investments are risky and it is important to cope with uncertainty. This paper deals with the uncertainty on a long term projection with an Age-Cohort approach. The authors used the jackknife technique to estimate confidence intervals and observe that the demographic approach outlines the structural determinants for long term trends of mobility.

Document type: Article

Token-Aware Completion Functions for Elastic Processor Verification

Scipedia content — Fri, 12 Feb 2021 14:01:26 +0100

We develop a formal verification procedure to check that elastic pipelined processor designs correctly implement their instruction set architecture (ISA) specifications. The notion of correctness we use is based on refinement. Refinement proofs are based on refinement maps, which—in the context of this problem—are functions that map elastic processor states to states of the ISA specification model. Data flow in elastic architectures is complicated by the insertion of any number of buffers in any place in the design, making it hard to construct refinement maps for elastic systems in a systematic manner. We introduce token-aware completion functions, which incorporate a mechanism to track the flow of data in elastic pipelines, as a highly automated and systematic approach to construct refinement maps. We demonstrate the efficiency of the overall verification procedure based on token-aware completion functions using six elastic pipelined processor models based on the DLX architecture.

Document type: Article

Multiship Crane Sequencing with Yard Congestion Constraints

Scipedia content — Fri, 12 Feb 2021 12:42:07 +0100

Crane sequencing in container terminals determines the order of ship discharging and loading jobs that quay cranes (QCs) perform, so that the duration of a vessel's stay is minimized. The ship's load profile, berthing time, number of available bays, and QCs are considered. More important, clearance and yard congestion constraints need to be included, which, respectively, ensure that a minimum distance between adjacent QCs is observed and yard storage blocks are not overly accessed at any point in time. In sequencing for a single ship, a mixed-integer programming (MIP) model is proposed, and a heuristic approach based on the model is developed that produces good solutions. The model is then reformulated as a generalized set covering problem and solved exactly by branch and price (B&P). For multiship sequencing, the yard congestion constraints are relaxed in the spirit of Lagrangian relaxation, so that the problem decomposes by vessel into smaller subproblems solved by B&P. An efficient primal heuristic is also designed. Computational experiments reveal that large-scale problems can be solved in a reasonable computational time.

Document type: Article

Planar Bragg Grating Sensors—Fabrication and Applications: A Review

Scipedia content — Fri, 12 Feb 2021 12:25:53 +0100

We discuss the background and technology of planar Bragg grating sensors, reviewing their development and describing the latest developments. The physical operating principles are discussed, relating device operation to user requirements. Recent performance of such devices includes a planar Bragg grating sensor design which allows refractive index resolution of 1 . 9 × 1 0 − 6 RIU and temperature resolution of 0 . 0 3 ∘ C . This sensor design is incorporated into industrialised applications allowing the sensor to be used for real time sensing in intrinsically safe, high-pressure pipelines, or for insertion probe applications such as fermentation. Initial data demonstrating the ability to identify solvents and monitor long term industrial processes is presented. A brief review of the technology used to fabricate the sensors is given along with examples of the flexibility afforded by the technique.

Document type: Article

Oil Dependence: Is Transport Running out of Affordable Fuel?

Scipedia content — Thu, 11 Feb 2021 14:24:48 +0100

The transport sector’s demand for oil is less price sensitive than any other part of the economy. This is partly because demand for transport services is relatively insensitive to price and partly because substitutes for oil in road transport are currently far from cost-effective. Evidence from the USA suggests that as incomes rise, transport sector oil demand becomes even less price sensitive. This implies that oil consumption is set to become increasingly concentrated in the transport sector. It also implies that relatively limited fluctuations in demand can have increasingly significant effects on oil prices.

Measuring FLOPS Using Hardware Performance Counter Technologies on LC systems

Scipedia content — Thu, 11 Feb 2021 14:20:17 +0100

FLOPS (FLoating-point Operations Per Second) is a commonly used performance metric for scientific programs that rely heavily on floating-point (FP) calculations. The metric is based on the number of FP operations rather than instructions, thereby facilitating a fair comparison between different machines. A well-known use of this metric is the LINPACK benchmark that is used to generate the Top500 list. It measures how fast a computer solves a dense N by N system of linear equations Ax=b, which requires a known number of FP operations, and reports the result in millions of FP operations per second (MFLOPS). While running a benchmark with known FP workloads can provide insightful information about the efficiency of a machine's FP pipelines in relation to other machines, measuring FLOPS of an arbitrary scientific application in a platform-independent manner is nontrivial. The goal of this paper is twofold. First, we explore the FP microarchitectures of key processors that are underpinning the LC machines. Second, we present the hardware performance monitoring counter-based measurement techniques that a user can use to get the native FLOPS of his or her program, which are practical solutions readily available on LC platforms. By nature, however, these native FLOPS metrics are notmore » directly comparable across different machines mainly because FP operations are not consistent across microarchitectures. Thus, the first goal of this paper represents the base reference by which a user can interpret the measured FLOPS more judiciously.

Congestion and air transport: a challenging phenomenon

Scipedia content — Mon, 08 Feb 2021 12:35:34 +0100

This paper deals with the problem of congestion in air transport. The focus is on the congested related delays at airports and en route. One of the solutions in the longer run is additional investment in new infrastructure, but in this article the major attention goes to the short run operational techniques to optimize the use of existing capacity. The pricing mechanism and slot allocation do not constitute a basic part of this article, as many academic publications already exist on these issues. During the years a lot of experience and successful solutions have been adopted in the US by the FAA and in Europe by the European Union and Eurocontrol. Whatever the solutions, constantly new challenges are looming beyond the horizon. Especially the relationship between noise related concerns and congestion is actually becoming a major problem.

INcreasing security and protection through infrastructure REsilience: The INSPIRE project

Scipedia content — Mon, 08 Feb 2021 12:24:45 +0100

The INSPIRE project aims at enhancing the European potential in the field of security by ensuring the protection of critical information infrastructures through (a) the identification of their vulnerabilities and (b) the development of innovative techniques for securing networked process control systems. To increase the resilience of such systems INSPIRE will develop traffic engineering algorithms, diagnostic processes and self-reconfigurable architectures along with recovery techniques. Hence, the core idea of the INSPIRE project is to protect critical information infrastructures by appropriately configuring, managing, and securing the communication network which interconnects the distributed control systems. A working prototype will be implemented as a final demonstrator of selected scenarios. Controls/Communication Experts will support project partners in the validation and demonstration activities. INSPIRE will also contribute to standardization process in order to foster multi-operator interoperability and coordinated strategies for securing lifeline systems.

Laserscanner Based ADAS for Motorcycle Safety

Scipedia content — Mon, 08 Feb 2021 12:24:32 +0100

Motorcyclists and moped drivers are road users with a particularly high accident risk since motorcycle accidents are severe in nature, due to the relative minor protection of motorcyclists. Furthermore, today the field of driver assistance systems is mostly dedicated to the passenger vehicle and heavy goods vehicle sector. Driver assistance systems for Powered Two Wheelers (PTWs), which rely on onboard vehicle sensors, have not been not considered so far. In this paper we present first results of the European funded Marie Curie research project MYMOSA and especially the Integrated Safety work within its work plan. The objective of the Integrated Safety work package is the development of an integrated safety system capable to detect impending dangerous situations and accident scenarios. As a consequence of the proposed activities in these projects a long-term reduction of at least 20% of injuries and fatalities of motorcyclists is foreseen.

A Control Scheme with Energy Saving and DC-Link Disturbance Rejection for Electric Vehicle

Scipedia content — Mon, 08 Feb 2021 10:21:45 +0100

control scheme for induction motor that integrates within a coherent solution some of the features that are commonly required to an electric vehicle drive is presented. The main features of the proposed control scheme are the capability to exploit the maximum torque in the whole speed range, a weak dependence on the motor parameters, a good robustness against the variations of the dc-link voltage and, whenever possible, the maximum efficiency. The effectiveness of the control scheme is confirmed by experimental tests.

Assessing the impact of future reconfigurable optical networks on application performance

Scipedia content — Mon, 08 Feb 2021 10:11:31 +0100

The introduction of optical private networks (lightpaths) has significantly improved the capacity of long distance network links, making it feasible to run large parallel applications in a distributed fashion on multiple sites of a computational grid. Besides offering bandwidths of 10 Gbit/s or more, lightpaths also allow network connections to be dynamically reconfigured. This paper describes our experiences with running data-intensive applications on a grid that offers a (manually) reconfigurable optical wide-area network. We show that the flexibility offered by such a network is useful for applications and that it is often possible to estimate the necessary network configuration in advance.

Seize the opportunity:The importance of timing for breaking commuters' car driving habits

Scipedia content — Mon, 08 Feb 2021 10:10:06 +0100

A study testing an innovative way to facilitate consumers' adoption of a socially responsible transport solution is reported. A large sample of Copenhagen car drivers were randomly assigned to either receive a free month travel card for public transportation or serve as a control group. It was predicted that the free travel card would neutralize the negative effect of car driving habits and make the use of public transportation more consistent with the traveller's conscious intentions, which was confirmed. The behavioural effects of the free travel card appeared only among individuals who had recently relocated residence or workplace prior to the intervention. This suggests that timing is essential when designing interventions to promote alternatives to car driving. A study testing an innovative way to facilitate consumers' adoption of a socially responsible transport solution is reported. A large sample of Copenhagen car drivers were randomly assigned to either receive a free month travel card for public transportation or serve as a control group. It was predicted that the free travel card would neutralize the negative effect of car driving habits and make the use of public transportation more consistent with the traveller's conscious intentions, which was confirmed. The behavioural effects of the free travel card appeared only among individuals who had recently relocated residence or workplace prior to the intervention. This suggests that timing is essential when designing interventions to promote alternatives to car driving.

Adaptive Framework and User Preference Modeling for Economy Class Aircraft Passenger Seat

Scipedia content — Mon, 08 Feb 2021 10:09:42 +0100

travel is becoming increasingly more accessible to people both through the availability of cheap flights and because the airlines are now able to cater for individuals of all ages and disabilities. Air travels, especially for long haul, may cause both physiological and psychological discomfort to passenger. Passenger comfort is clearly a main factor in user’s acceptance of transportation systems. The paper presents an adaptive framework and user preference model for economy class aircraft passenger seat. The adaptive framework is based on the passenger’s current and target sitting comfort states to reduce the sitting discomfort. The system uses a seat feedback system to regulate the passenger sitting comfort. The user preference model is used for personalized seat service delivery systems.

Hybrid-assisted DPF regeneration in distribution trucks

Scipedia content — Mon, 08 Feb 2021 10:09:15 +0100

TNO Automotive is developing an Integrated Powertrain Control (IPC) concept for powertrain controls that focuses on integration of the engine, aftertreatment and parallel hybrid electric system. One of the first steps is the focus on hybrid assisted Diesel Particulate Filter (DPF) regeneration. For inner-city distribution trucks the legislation on particulate matter is becoming more stringent. This means that diesel particulate filters will be increasingly applied to inner-city distribution trucks. The fact that these trucks often operate at idle- and part-load poses a great challenge to the successful regeneration of the DPF. Based on a simulation study, the capability of hybrid-assisted DPF regeneration is shown, along with the additional requirements placed on the hybrid components.

The efficiency of low-cost airlines' operations in Europe

Scipedia content — Mon, 08 Feb 2021 09:50:51 +0100

Low-cost carriers operate no-frills point-to-point services, focusing on medium and short-haul origin-destination markets. Indeed, low-cost airlines sell to travellers a product with very simple features, which enable them to operate at a much lower cost per unit of output, compared to full-service carriers. Over the last decade, low-cost carriers have dramatically increased their market shares and nowadays they control about the 20% of the intra-European market in terms of flight frequencies and more than the 30% in terms of seats offered in the same market. This paper presents an overview of the operational, economic and environmental performances of a sample of European low-cost carriers. Different methodologies and indices are applied in order to obtain a set of quantitative results, so that proper comparisons can be conducted and general conclusions can be drawn.

Design and Development of an ATC Distributed Training System

Scipedia content — Mon, 08 Feb 2021 09:48:37 +0100

The current development of an “European Air Traffic Management Network” is emphasizing the role of training activities for controllers. The most advanced training centers are equipped with tower, radar and flight simulators in which all the phases of air traffic control process (including the pilot’s condition) can be reproduced with an high degree of realism. Therefore, these systems mostly operate stand alone not exploiting the challenge of connecting single platforms in a unique distributed environment. In this paper a distributed training system is designed and experimented. It includes traffic simulation, flight simulation and real time voice communications. Air traffic in approach, landing and ground operations is simulated in a virtual air field and displayed on a table-top interface. One of the flight animations is performed in real time connecting the table-top with a FFS (Fixed Flight Simulator). The other planes which animate the environment follow recorded paths. Once the simulation is performed, training activities continue using an off-line virtual debriefing tool of the simulated ATC process. The whole system aims at providing the controller with the awareness about the tasks performed by pilots and their consequences on the ATC scenario development.

A mathematical solution to power optimal pipeline design by utilizing soft edge flip-flops

Scipedia content — Wed, 03 Feb 2021 21:49:29 +0100

This paper presents a novel technique to minimize the total power consumption of a synchronous linear pipeline circuit by exploiting extra slacks available in some stages of the pipeline. The key idea is to utilize soft-edge flip-flops to enable time borrowing between stages of a linear pipeline in order to provide the timing-critical stages with more time to complete their computations. Time borrowing, in conjunction with keeping the clock frequency unchanged, gives rise to a positive timing slack in each pipeline stage. The slack is subsequently utilized to minimize the circuit power consumption by reducing the supply voltage level. We formulate and solve the problem of optimally selecting the transparency window of the soft-edge flip-flops and choosing the minimum supply voltage level for the pipeline circuit as a quadratic program, thereby minimizing the power consumption of the linear pipeline circuit under a clock frequency constraint. Experimental results prove the efficacy of the problem formulation and solution technique.

Power Optimization of Pipelined ADCs with High-Order Digital Gain Calibration

Scipedia content — Wed, 03 Feb 2021 21:42:47 +0100

Digital calibration techniques are widely utilized to linearize pipelined A/D converters (ADCs). However, their power dissipation can be prohibitively high, especially when high-order gain calibration is needed. For high-order gain calibration, this paper proposes a design methodology to optimize the data precision (number of bits) within the digital calibration unit. Thus, the power dissipation of the calibration unit can be minimized, without affecting the linearity of the pipelined ADC. A 90-mn FPGA synthesis of a 2nd-order digital gain-calibration unit shows that the proposed optimization methodology results in a 59% reduction in power dissipation.

Examining Airspace Structural Components and Configuration Practices for Dynamic Airspace Configuration

Scipedia content — Wed, 03 Feb 2021 21:42:19 +0100

Dynamic Airspace Configuration (DAC) is a new operational paradigm that proposes to migrate from the current structured, static airspace to a dynamic airspace capable of adapting to user demand while meeting changing constraints of weather, traffic congestion and complexity, as well as a highly diverse aircraft fleet (Kopardekar et al., 2007). To understand how the air traffic system can transform from current airspace structures and operational practices to what is envisioned in the NextGen operations, current airspace structures and configuration practices are cataloged in this paper. The purpose of this paper is twofold. The first purpose is to introduce and summarize current airspace structures to researchers who may not be familiar with them and describe specific examples on how these structures are currently used in the operational contexts at different facilities. The second purpose is to describe the near to mid-term operational implementations planned by the Federal Aviation Administration (FAA) to researchers whose focus is on far-term concepts but may not be aware of the transition pathway to the far-term concepts. These near to midterm implementations modify and/or extend the current airspace structures to provide greater flexibility and efficiency in air travel. The paper explores how the proposed airspace structures may be extended further to the NextGen timeframe with fully dynamic airspace and a mixture of highly equipped aircraft fleet.

The influence of potential policy measures on the eco-efficiency of personal vehicle mobility in Brussels

Scipedia content — Wed, 03 Feb 2021 21:33:44 +0100

This paper on the eco-efficiency of personal vehicle mobility in Brussels is from the proceedings of 14th international Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors consider the influence of potential policy measures on the eco-efficiency of personal vehicle mobility, noting that urban areas such as the Brussels Capital Region (BCR) are facing air quality issues, due to a dense road network, a high degree of motorization, and a large influx of commuters entering the city daily. The authors then outline several possible policy measures that could be implemented by the Brussels Regional Government to influence the characteristics or intensity of urban traffic as well as its impact on the environment. These measures include a reorientation of the fiscal system for vehicles (registration and circulation tax), applying a road or congestion charge, variable parking fees, and other strategies. The Brussels Regional Government has commissioned a study to investigate the effects of these different policy measures on the traffic intensity in the city, as well as on the environment and the eco-efficiency of the vehicle fleet. The study will include costs and purchasing behavior as well as how the use of vehicles could evolve. The authors briefly describe how the Ecoscore, an environmental indicator for vehicles, is applied as a tool for policy support.

Traffic distribution over equal-cost-multi-paths

Scipedia content — Wed, 03 Feb 2021 21:32:34 +0100

To effectively manage the traffic distribution inside a network, traffic splitting is needed for load sharing over a set of equal-cost-multi-paths (ECMPs). In this paper, a new traffic splitting algorithm, called Table-based Hashing with Reassignments (THR), is proposed. Based on the load sharing statistics collected, THR selectively reassigns some active flows from the over-utilized paths to under-utilized paths. The reassignment process takes place in such a way that the packet out-of-order problem is minimized. As compared with the existing traffic splitting algorithms, THR provides close-to-optimal load balancing performance, less than 2% of packets arrived out-of- order, and a very small end-to-end packet delay performance. Although additional traffic monitoring function is needed by THR, we show that the extra complexity incurred is marginal.

A comparative exploration of eye gaze and head motion cues for lane change intent prediction

Scipedia content — Wed, 03 Feb 2021 21:32:20 +0100

Driver behavioral cues may present a rich source of information and feedback for future intelligent driver assistance systems (IDAS). Two of the most useful cues might be eye gaze and head motion. Eye gaze provides a more accurate proxy than head motion for determining driver attention, whereas the measurement of head motion head motion as a derivative of pose is less cumbersome and more reliable in harsh driving conditions. With the design of a simple and robust IDAS in mind, we are interested in determining the most important driver cues for distinguishing driver intent. We use a lane change intent prediction system [1] to determine the relative usefulness of each cue for determining intent. Various combinations of input data are presented to a discriminative classifier, which is trained to output a prediction of probable lane change maneuver at a particular point in the future. Quantitative results using real-world data are presented and show that head motion, when combined with lane position and vehicle dynamics, is a reliable cue for lane change intent prediction. The addition of eye gaze does not improve performance as much as simpler head pose-based cues.

MONTE: an implementation of an MPLS online traffic engineering tool

Scipedia content — Wed, 03 Feb 2021 21:29:54 +0100

International audience; Multiservice networks require careful mapping of traffic in order to provide quality of service. Applying offline Traffic Engineering techniques leads to a better usage of resources and allows to assure some degree of quality of service. Even with those techniques applied, as network and traffic conditions change dynamically, the initial quality could be reduced. When addressing this problem, online Traffic Engineering has a major role. In MONTE project a solution for addressing this problem in Multiprotocol Label Switching networks was proposed and implemented in software. Such solution involves network discovering and monitoring, congestion detection, a corrective algorithm, and a mechanism for signalling changes in the network. The entire solution was conceived to work in real time and vendor independent. This paper explains the details of the solution and its implementation. Results validating the correct operation of the tool are also shown. This results were obtained through tests in a live network.

Role of railway traffic in public urban and suburban passenger transport (example of the City of Zagreb)

Scipedia content — Wed, 03 Feb 2021 21:28:00 +0100

One of the basic problems of all the mid-size and bigger European cities is permanent increase in the demand for passenger transport services, but also increase in individual automobile traffic. Apart from environmental pollution such urban mobility results in constant road congestions in urban areas, endangering also the safety of traffic participants. All the European cities face the mentioned problems, which directly affects the quality of living there, attractiveness and economic development. In order to increase mobility at the same time, and to reduce the congestion, traffic accidents and environmental pollution, it is necessary to reduce and limit the individual traffic in urban and suburban traffic systems, and increase the share of railway, which has a series of direct and indirect comparative advantages over other traffic modes (very low harmful emissions, lower energy consumption, higher speed which allows significant savings in travel time, stimulation of suburban zones development, etc.). Therefore, the railway should have a dominant role in urban and suburban passenger transport, i.e. it should be the fundamental part of the system, which is upgraded by other subsystems. The paper studies the role and significance of the railways in public urban and suburban passenger transport in the City of Zagreb. Apart from the analysis of the existing situation in public urban transport in the City of Zagreb and the current role of railway in the public urban transport (PUT) system, which has not been sufficiently used yet, special emphasis is given on the projection of the future role of railways in PUT flow, including the new routes which would along with the existing infrastructure allow its greater share and a more significant role in the PUT system.

AMANDA V3: Toward a Common Workspace between Air Traffic Controllers

Scipedia content — Wed, 03 Feb 2021 21:09:01 +0100

International audience; This paper presents the different tools developed in the LAMIH, in optics to assist air traffic controllers in their tasks, to decrease their workloads, and to enable them to support the ceaseless increase of the traffic. Common philosophy to all these tools is to preserve the controllers in the loop: we do not try to develop tools entirely automatic. The platform AMANDA V2 made it possible to set up and to evaluate a common workspace, which allows the two controllers of a sector to cooperate and to share the same representation of their traffic and conflicts. This space maintains common situation awareness. This tool was very appreciated by professional controllers and we now wish to extend this principle to the cooperation between two planning controllers of two adjacent sectors. It is what we present in this paper which begins with a presentation of the ATC then a point on the platforms of the laboratory and particularly AMANDA V2, to conclude with the objectives of AMANDA V3.

Extraction of Suspicious Behavior of Vessels in the Exclusive Economic Zone

Scipedia content — Wed, 03 Feb 2021 21:01:57 +0100

vailable: http://ap-s.ei.tuat.ac.jp/isapx/2008/pdf/1645005.pdf; International audience; Introduction: Constant growth of world maritime transport and significant economic stakes of territorial water management have prompted the international community to invest in maritime global security research. In this context, the ScanMaris project, which is founded by the French National Research Agency (ANR), aims to continuously monitor activities in the Exclusive Economic Zone (EEZ) activities and detect abnormal behavior using both observation systems and external data sources.

Analysis of different cost functions in the Geosect airspace partitioning tool

Scipedia content — Wed, 03 Feb 2021 20:48:01 +0100

new cost function representing air traffic controller workload is implemented in the Geosect airspace partitioning tool. Geosect currently uses a combination of aircraft count and dwell time to select optimal airspace partitions that balance controller workload. This is referred to as the aircraft count/dwell time hybrid cost function. The new cost function is based on Simplified Dynamic Density, a measure of different aspects of air traffic controller workload. Three sectorizations are compared. These are the current sectorization, Geosect's sectorization based on the aircraft count/dwell time hybrid cost function, and Geosect's sectorization based on the Simplified Dynamic Density cost function. Each sectorization is evaluated for maximum and average workload along with workload balance using the Simplified Dynamic Density as the workload measure. In addition, the Airspace Concept Evaluation System, a nationwide air traffic simulator, is used to determine the capacity and delay incurred by each sectorization. The sectorization resulting from the Simplified Dynamic Density cost function had a lower maximum workload measure than the other sectorizations, and the sectorization based on the combination of aircraft count and dwell time did a better job of balancing workload and balancing capacity. However, the current sectorization had the lowest average workload, highest sector capacity, and the least system delay.

On the Double-Faced Nature of P2P Traffic

Scipedia content — Wed, 03 Feb 2021 20:45:59 +0100

Over the last few years, peer-to-peer (P2P) file sharing applications have evolved to become a major traffic source in the Internet. The ability to quantify their impact on the network, as a consequence of both signaling and download traffic, is fundamental to a number of network operations, including traffic engineering, capacity planning, quality of service, forecasting for long-term provisioning, etc. We present here a measurement study on the characteristics of the traffic associated with different P2P applications. Our aim is to offer useful insight into the nature of P2P traffic, which we consider a step toward building P2P traffic aggregates generators in simulative environments. We show that P2P traffic can be divided into two distinguished behavioral profiles, which, independently of the application protocol, present significant differences in the average and standard deviation of four measurements: arrival times, durations, volumes and average packet sizes ofP2P conversations. These profiles well represent the typical behavior of signaling and download traffic. Based on our findings, we argue that, if such distinction is not taken into account, the statistical measurements needed to model P2P traffic aggregates would result biased, and potentially bring to misleading results.

Solving dynamic multi-objective problems with vector evaluated particle swarm optimisation

Scipedia content — Wed, 03 Feb 2021 20:38:41 +0100

Many optimisation problems are multi-objective and change dynamically. Many methods use a weighted average approach to the multiple objectives. This paper introduces the usage of the vector evaluated particle swarm optimiser (VEPSO) to solve dynamic multi-objective optimisation problems. Every objective is solved by one swarm and the swarms share knowledge amongst each other about the objective that it is solving. Not much work has been done on using this approach in dynamic environments. This paper discusses this approach as well as the effect of the population size and the response methods to a detected change on the performance of the algorithm. The results showed that more non-dominated solutions, as well as more uniformly distributed solutions, are found when all swarms are re-intialised when a change is detected, instead of only the swarm(s) optimising the specific objective function(s) that has changed. Furthermore, an increase in population size results in a higher number of non-dominated solutions found, but can lead to solutions that are less uniformly distributed.

Public transportation: a method for decreasing the traffic load in large cities

Scipedia content — Wed, 03 Feb 2021 20:22:20 +0100

This paper on a method of public transportation used to decrease the traffic load in large cities is from the proceedings of 14th International Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors describe the impacts of public transportation on fuel consumption, pollution and traffic load in Ahwaz city, Iran. They also compare private and public bus networks in Ahwaz, both to each other and to the international standards. They conclude that, considering the yearly increase of passenger demand in Ahwaz and the population growth, the public transportation system should be enhanced. Some components that have slowed the public's acceptance of the bus system, such as the lack of air-conditioning in buses in this very hot climate, must be addressed. A brief list of suggestions that could be used to improve the public transportation system, specifically buses, concludes the paper.

Advanced national airspace traffic flow management simulation experiments and vlidation

Scipedia content — Wed, 03 Feb 2021 20:14:53 +0100

Traffic flow management in the National Airspace is an important problem in our air transportation system. We have developed ProbTFM, a traffic flow management evaluation platform and algorithmic solution. ProbTFM works with existing traffic flow management tools and provides probabilistic data modeling and decision making. ProbTFM forecasts airport and airspace capacity and demand; and airport, airspace, and route congestion. ProbTFM creates a list of high congestion, "critical" flights and recommends delays or reroutes for specific flights. ProbTFM can be used as an evaluation platform for advanced traffic flow management concepts, and to model today's National Airspace System. In this paper we report on validation results and how ProbTFM can be used to understand operational tradeoffs and inform policy decisions.

Study of Cockpit's Perspective on Human-Human Interactions to Guide Collaborative Decision Making Design in Air Traffic Management

Scipedia content — Wed, 03 Feb 2021 20:10:39 +0100

This field research studies human-human interactions (HHI), seen from cockpit's perspective in context of collaborative decision making (CDM) during flight operation situations. It is based on the assumption that cooperation among all participating operators achieves positive effect on CDM operation. The aim of the research is to identify, how factors driving cooperative behaviour are established in flight operation situations during day-today HHI at action level. Obtained results are used to guide future CDM design with simulation software development and system behaviour simulation. In this paper, a cockpit survey is introduced which examines two highly dynamic flight operation situations. Both situations are usually time constrained, change quickly and require synchronous human-human cooperation between pilots and multiple other operators. The first one, turn-round operation, involves HHI with information sharing via face-to-face or technological means and HHI with task/decision making distribution between pilots and other operators. The second one, the flight operation itself, involves HHI with information sharing only via technological means and HHI with task/decision making distribution between pilots and other operators.

Modelling traffic in detail with mesoscopic models: opening powerful new possibilities for traffic analyses

Scipedia content — Wed, 03 Feb 2021 19:58:38 +0100

This paper on modeling traffic with mesoscopic models is from the proceedings of 14th international Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors describe this new model type and use a new development in the Cube transport planning software package, Cube Avenue, to demonstrate how mesoscopic dynamic traffic assignment models can help model very congested areas to the level of detail required for traffic engineering and area traffic control. With the mesoscopic Cube Avenue program, an extension of the macroscopic planning tool, Cube Voyager, analysts can study problems for which traditional models don’t provide enough data and for which microscopic models provide too much data. One section briefly describes currently ongoing model developments in the U.S., the U.K., Scandinavia, Europe, and Australia, where Cube Avenue is being used to study and optimize area traffic control, to examine blocking effects caused by tolling, and general traffic management and planning issues.

Abstraction Techniques for Capturing and Comparing Trajectory Predictor Capabilities and Requirements

Scipedia content — Wed, 03 Feb 2021 19:58:04 +0100

on Techniques for Capturing and Comparing Trajectory Predictor Capabilities and Requirements Robert A. Vivona L-3 Communications, Billerica, MA 01821 Karen T. Cate and Steven M. Green NASA Ames Research Center, Moffett Field, CA 94035 Recent research has increased focus on the conceptual design, development and use of airand ground-based aircraft trajectory prediction capabilities to support advanced Air Traffic Management concepts. In both the United States and Europe, the sharing of fourdimensional trajectory information between many automation systems will be necessary for successful operations. Understanding the functional and performance differences between disparate trajectory predictors is critical for enabling this system interoperability. Documented capabilities for four existing trajectory predictors were compared to identify commonalities and differences. For effective comparison, it was first necessary to abstract the prediction capabilities of each trajectory predictor. Three abstraction techniques were developed. The first separated the description of modeled aircraft behavior from the associated mathematical models used to integrate the predicted trajectory. The second defined a conceptual boundary between the trajectory predictor and its client application. The third eliminated the use of domain specific terminology. The abstraction techniques proved not only beneficial for comparing trajectory prediction capabilities, but also for defining trade-offs between the compatibility and accuracy of disparate TPs to achieve system interoperability.

Positioning a traffic congestion management plan within South African planning

Scipedia content — Wed, 03 Feb 2021 19:50:16 +0100

This paper on traffic congestion management in South Africa is from the proceedings of 14th International Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors of this paper support the use of Integrated Development Plans (IDPs) to integrate supply, demand and land-use management measures within regional planning processes that coordinate and align many local and district level functions. Although the South African IDP provides a framework to develop potentially highly integrated strategies, this approach lacks a direct mechanism to manage traffic congestion as part of the IDP process. The authors report the results of a recent study that emphasized the need to develop a specific Traffic Congestion Management Plan (TCMP) as a component of the South African IDP. The TCMP should include traffic survey and assessment; a model that uses multi-modal travel options including highways and transit; assessment of traffic congestion, including that created by new and regenerated development; the identification of measures to manage traffic congestion; project scheduling, particularly for implementation of TCMP projects; the development of an investment strategy; and the monitoring and evaluation of completed projects.

Functional Building Blocks for an Integrated Aeronautical IP-Network

Scipedia content — Wed, 03 Feb 2021 19:42:54 +0100

Within the next 10-15 years, air-traffic management (ATM) will be primarily based on data communications and voice communication will be mostly used as fallback solution. Furthermore, it is foreseen that IP-based networking solutions for A/G communication will be deployed for cost savings, high reliability and an optimal alignment with the evolution of communication and security technologies. Such an efficient and sustainable data network for aeronautical communications is required to enable the implementation of a range of operational improvements needed to support the expected growth in air transportation. An IP-based global aeronautical communication network is currently being developed within the NEWSKY project, co-funded by the European Commission and in close collaboration with Eurocontrol and ICAO ACP WG-I (Specification of ATN/IPS). NEWSKY pursues the vision of "Networking the Sky" by integrating different data link technologies (long range A/G links, airport links, satellite links) and different services (ATS, AOC/AAC, APC) in a single, seamless network. Key functionalities have been identified, namely resource management, mobility, security and end-to-end data transport. In this paper, the raw functional architecture and the ongoing activities towards the specification of the functional modules are investigated.

Data Pipeline From CAD to AR Based Assembly Instructions

Scipedia content — Wed, 03 Feb 2021 19:36:04 +0100

One of the main challenges of introducing Augmented Reality technology into industrial applications is fast, reliable, low-cost authoring of animated AR content of product data created in 3D CAD systems. In this paper we present a product data information pipeline from industry used commercial CAD systems to a marker-based augmented reality system. The pipeline utilizes ISO 10303 (STEP) data protocol, DFA-Tool (Design For Assembly), and VTT’s proprietary content creation and augmenting software. The pipeline is verified with a real industrial application.

Emission inventory for urban transport in the rush hour: application to Seville

Scipedia content — Wed, 03 Feb 2021 19:33:39 +0100

Energy and transport are indispensable ingredients for economic and social development. At the same time conventional forms of energy production, distribution and consumption as well as sustainable transport and mobility patterns are linked to environmental degradation. The goal of the work is to develop a decision support system able to help local administrators in reducing the impact of air pollution due to urban traffic. The method designed is a framework, which included a transportation planning tool and a comprehensive model to estimate pollutants emissions. The hourly traffic flow data is obtained from transportation planning, and the emission model integrated is based on COPERT methodology. Detailed traffic data have been collected and analyzed from the city of Seville to test the methodology.

Lyapunov based stability analysis for metro lines

Scipedia content — Wed, 03 Feb 2021 19:18:08 +0100

In this work a direct method to measure the stability of metro system lines with respect to a previously constructed time schedule is presented. For this purpose we first model saturation effects using a real time discrete space state representation and then apply a Lyapunov-based stability analysis considering time delays of trains as disturbances. As a result we have been able to define a new set of indexes that relate time delays with the validity of the actual time schedule when falling inside a particular ‘stability area’. Results obtained in a simulated environment show that the new stability indexes are able to evaluate quantitatively and qualitatively the effects of saturation in metro lines as well as predict the need for rescheduling Keywords: metro system, stability, planning, genetic algorithm, artificial intelligence. 1 Introduction The dynamics of metro line systems have been deeply studied by several researchers [1–5,7–10]. Most of these dynamical models are based on the Sasama and Ohkawa [9] linear model. It is well known that such kind of linear models, usually yield simple formulation, implementation and simulation. As a result, some dynamic traffic linear controllers [1–3,7] and real time simulators [3,4] have been proposed.

Analysis of airspace tube structures

Scipedia content — Wed, 03 Feb 2021 19:17:31 +0100

This paper presents analysis of five airspace tube structures; three of which were previously defined and two new designs that were generated for this research. Five metrics to characterize the performance of these tubes are described. The metrics address the spatio-temporal utilization, frequency and angles at which aircraft cross tubes, along with separation of aircraft with and without tubes. All of the designs were incorporated in a common simulation platform for evaluation. The results indicate that current designs of tubes have low utilization and improvements are needed for additional benefits. Other structural parameters for consideration in future designs are presented along with visualization of a simple three-dimensional tube network.

Automated design of self-adjusting pipelines

Scipedia content — Wed, 03 Feb 2021 19:02:27 +0100

We propose a self-adjusting pipeline structure to enhance chip performance and robustness considering the effects of process variations. We achieve this by introducing delay sensors to monitor internal timing violations within a pipeline stage and variable clock skew buffers to adjust the timing of the pipeline stage based on the feedback from the delay sensors. Furthermore, we formulate the delay sensor insertion and variable clock skew configuration problem as a stochastic mixed-integer programming problem and propose a simulated-annealing based algorithm to solve it. A comparison between the designs with and without the self-adjusting enhancement reveals that, we are able to improve the average performance of a batch of chips by 9.5%.

Embedding technologies for an automotive radar system

Scipedia content — Wed, 03 Feb 2021 18:58:28 +0100

Radar sensors are already employed in production model vehicles e.g. for adaptive cruise control (ACC) systems. Further development of driver assistance systems has also led to the use of radar sensors in active safety systems (active brake assistance, collision warning, emergency braking, etc). However, the costs of manufacturing such radar-based systems, capable of gathering reliable information from surroundings, for vehicles across the market spectrum or for compact executive cars are still too high. Thus, despite the improved reliability characteristics, detection properties and safety required for these sensors, the aim is to manufacture such systems more cost-effectively. The German national "KRAFAS (Cost-optimized Radar Sensor for Active Driver Assistance Systems)" project is aiming at integrating 77 GHz components (esp. SiGe MMICs) into a printed circuit board, combining driver and 77 GHz RF circuitry and integrating antenna elements. This will significantly reduce current costs of the 77 GHz RF module by 20-30%. A sketch of such a module with an adapted cylindrical radar lens is depicted in Figure 1. [GRAPHICS] In this paper, design, simulation, technological development, demonstrator realization and subsequent measurement of interconnects of embedded active 77 GHz chips to a high frequency substrate using microvia technology is described. The used molded embedding technology offers great opportunities for a very broad range of frequencies and applications as well as large potential for cost reduction.

Statistics and Social Network of YouTube Videos

Scipedia content — Wed, 03 Feb 2021 18:57:02 +0100

YouTube has become the most successful Internet website providing a new generation of short video sharing service since its establishment in early 2005. YouTube has a great impact on Internet traffic nowadays, yet itself is suffering from a severe problem of scalability. Therefore, understanding the characteristics of YouTube and similar sites is essential to network traffic engineering and to their sustainable development. To this end, we have crawled the YouTube site for four months, collecting more than 3 million YouTube videos' data. In this paper, we present a systematic and in-depth measurement study on the statistics of YouTube videos. We have found that YouTube videos have noticeably different statistics compared to traditional streaming videos, ranging from length and access pattern, to their growth trend and active life span. We investigate the social networking in YouTube videos, as this is a key driving force toward its success. In particular, we find that the links to related videos generated by uploaders' choices have clear small-world characteristics. This indicates that the videos have strong correlations with each other, and creates opportunities for developing novel techniques to enhance the service quality.

The Concept of Autonomy in Distributed Computation and Multi-agent Systems

Scipedia content — Wed, 03 Feb 2021 18:53:44 +0100

The paper presents multi agent system approach and software prototype aimed at the air traffic control in airport airspace. The system consists of agents playing roles of assistant aircraft crews and assistant air traffic control operator of approach zone. According to selected organizational structure of multi agent system two different approaches to air traffic control are used. Within the approach zone coordination of agents' behavior is based on decisions made by assistant operator agent. Within the arrival zone assistant aircraft crews' agents make decision autonomously using a priory agreed behavior policy.

Simulating air traffic blockage due to convective weather conditions

Scipedia content — Wed, 03 Feb 2021 18:19:54 +0100

Monte Carlo methodology is proposed for simulating air traffic blockage patterns under the impact of convective weather. The simulation utilizes probabilistic convective weather forecasts such as those produced by the 1-6 hour National Convective Weather Forecast. A matrix of random numbers is fed to the simulation process to obtain an instantiation of traffic blockage maps. Gaussian smoothing with varying Full Width at Half Maximum across the grid is employed to model the varying spatial correlation between cells. Special Cellular Automata techniques are employed to model the evolvement, i. e. the trend, growth, and dissipation of convection, between consecutive time intervals. Model parameters are obtained from analyzing historical convective weather data. A software tool is also developed to implement the simulation methodology. The simulation methodology thus provides a means to improve the utilization of short term probabilistic convective weather forecast products, and to improve air traffic efficiency in the large.

HyHOPE: Hybrid Head Orientation and Position Estimation for vision-based driver head tracking

Scipedia content — Wed, 03 Feb 2021 18:17:57 +0100

Driver distraction and inattention are prominent causes of automotive collisions. To enable driver assistance systems to address these problems, we require new sensing approaches to infer a driverpsilas focus of attention. In this paper, we present a new 3D tracking algorithm and integrate it into HyHOPE, a real-time (30 fps) hybrid head orientation and position estimation system for driver head tracking. With a single video camera, the system continuously tracks the head in six degrees-of-freedom, initializing itself automatically with separate modules for head detection and head pose estimation. The tracking module provides a fine estimate of the 3D motion of the head, using a new appearance-based algorithm for 3D model tracking by particle filtering in an augmented reality environment. We describe our implementation, which utilizes OpenGL-optimized graphics hardware to efficiently compute particle samples in real-time. To quantitatively evaluate the accuracy of our system, we compare its estimation results to a marker-based cinematic motion capture system installed in an automotive testbed. We evaluate the system on real daytime and nighttime drives with drivers of varying ages, race, and sex.

The Family of 4-phase Latch Protocols

Scipedia content — Wed, 03 Feb 2021 18:12:39 +0100

complete family of untimed asynchronous 4-phase pipeline protocols is derived and characterised. This family contains all untimed protocols where data becomes valid before the request signal rises. Starting with a specification of the most parallel such protocol, rules are provided for concurrency reduction to systematically generate the family of all 137 related protocols that can be pipelined. Graphical and textual nomenclatures are developed to represent protocol properties and behaviours. The protocols are categorised according to their behaviours when composed into linear and structured parallel pipelines. Six basic categories emerge, along with several properties such as a single state that determines whether a protocol is fully or half buffered. When equivalence classes are calculated for parallel pipeline behaviours they are dominated by 15 shapes (all of which are delay-insensitive) which are related by a simple lattice. Several published circuits are shown to map to 16 of our 137 family members. This work enhances the understanding of handshake protocols, their properties, and relationships between different implementations in terms of concurrency and behavioural properties.

Robust and reactive traffic engineering for dynamic traffic demands

Scipedia content — Wed, 03 Feb 2021 18:06:42 +0100

International audience; Traffic engineering (TE) has become a challenging mechanism for network management and resources optimization due to uncertain and difficult to predict traffic patterns. Recent works have proposed robust optimization techniques to cope with uncertain traffic, computing a stable routing configuration that is immune to demand variations within certain uncertainty set. However, using a single routing configuration for longtime periods can be highly inefficient. Even more, the presence of abnormal and malicious traffic has magnified the network operation problem, claiming for solutions which not only deal with traffic uncertainty but also allow to detect and identify faulty traffic to take the appropriate countermeasures. In this paper, we introduce the Reactive Robust Routing (RRR) for TE, an approach that combines both proactive and reactive techniques to tackle the problem. Based on expected traffic patterns, we adapt the uncertainty set and build a multi-hour yet robust routing scheme that outperforms the stable robust approach. For the case of anomalous and unexpected traffic, we propose a fast anomaly detection/isolation algorithm to detect and localize abrupt changes in traffic flows and decide routing changes. This algorithm is optimal in the sense that it minimizes the decision delay for a given mean false alarm rate and false isolation probability. We validate these proposals using real data from two different backbone networks and we show how the RRR can handle uncertain and highly dynamic traffic in an automatic fashion, simplifying network operation.

Vision-based analysis of pedestrian traffic data

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

Reducing traffic congestion has become a major issue within urban environments. Traditional approaches, such as increasing road sizes, may prove impossible in certain scenarios, such as city centres, or ineffectual if current predictions of large growth in world traffic volumes hold true. An alternative approach lies with increasing the management efficiency of pre-existing infrastructure and public transport systems through the use of intelligent transportation systems (ITS). In this paper, we focus on the requirement of obtaining robust pedestrian traffic flow data within these areas. We propose the use of a flexible and robust stereo-vision pedestrian detection and tracking approach as a basis for obtaining this information. Given this framework, we propose the use of a pedestrian indexing scheme and a suite of tools, which facilitates the declaration of user-defined pedestrian events or requests for specific statistical traffic flow data. The detection of the required events or the constant flow of statistical information can be incorporated into a variety of ITS solutions for applications in traffic management, public transport systems and urban planning.

Toward a graphical user interface for the SPIRE spectrometer pipeline

Scipedia content — Wed, 03 Feb 2021 18:02:05 +0100

International audience; Herschel is a satellite mission led by ESA and involving an international consortium of countries. The HCSS is in charge of the data processing pipeline. This pipeline is written in Jython and includes java classes. We present a convenient way for a user to deal with SPIRE photometer and spectrometer pipeline scripts. The provided Graphical User Interface is built up automatically from Jython script. The user can choose tasks to be executed, parameterise them and set breakpoints during the pipeline execution. Results can be displayed and saved in FITS and VOTable formats.

Unifying Real-Time Multi-Vehicle Tracking and Categorization

Scipedia content — Wed, 03 Feb 2021 17:50:45 +0100

This paper addresses real-time automatic visual tracking and classification of a variable number of vehicles in traffic. This off-board surveillance device may cooperate with on-board Advanced Driver Assistance Systems (ADAS), extending its measurement range to the areas of the road that are not in the car sensors field-of-view (in a curve or an intersection). Tracking results also are useful for statistical trajectory analysis, devoted to understanding and improving user-user and user-infrastructure interactions. As a main contribution, this paper proposes to unify vehicle tracking and classification in a single processing step. This paper also addresses a vehicle anisotropic distance measurement based on the vehicle 3D geometric model. Real time tracking results are shown and discussed on road sequences involving various types of vehicles such as motorcycles, cars, light trucks and heavy trucks.

A Demonstration of an Aircraft Intent Interchange Specification for Facilitating Trajectory-Based Operations in the National Airspace System

Scipedia content — Wed, 03 Feb 2021 17:47:54 +0100

International research into Air Traffic Management technologies has accelerated over the last ten years. The Federal Aviation Administration (FAA), National Aeronautics and Space Administration, and EUROCONTROL each have on-going research in TrajectoryBased Management in their efforts to decrease Air Traffic Controller workload while increasing air traffic capacity and reducing the effects of adverse weather conditions and bottleneck areas. Additionally, each of these organizations has interest in standardizing developing technologies. Towards this end, the FAA and the Boeing Company have established a Cooperative Research & Development Agreement designed to facilitate development in Trajectory-Based Operations. To initiate this cooperative research, the Target Generation Facility (TGF) of the FAA William J. Hughes Technical Center has conducted concept demonstration research of a promising specification standard: the Aircraft Intent Description Language (AIDL), developed by Boeing Research & Technology Europe. AIDL is a formal language for the unambiguous definition of aircraft trajectories. It is intended as a univocal, rigorous, and standardized manner to interchange aircraft intent information for ATM purposes. The purpose of the TGF research was to demonstrate the concept that AIDL can be used to interchange aircraft intent information to a trajectory predictor and to an aircraft simulator and that the resultant predicted and simulated trajectories would be compatible. This study used the TGF Trajectory Predictor (TP) and the TGF Simulator. An interface compatible with AIDL was developed for each. The results of this study show that AIDL can be used to efficiently and completely define an aircraft trajectory, can be used to interchange aircraft intent information, and will result in compatible trajectories in a TP and a flight simulator.

Flight-Deck Automation for Trajectory-Based Surface Operations

Scipedia content — Wed, 03 Feb 2021 17:35:03 +0100

To address anticipated growth in air traffic demand, the Surface Operation Automation Research (SOAR) is a collection of research activities designed with the common goal to explore and develop automation technologies for enhancing surface movement efficiency at major airports. The concept features a tower automation system that collaborates with a flight-deck automation system to jointly deliver highly efficient and safe surface operations. The tower automation counts on the availability of advanced surveillance data to plan timed surface operations. The time-based trajectories are communicated to the flight decks as 4- dimensional (4D) trajectory clearances via digital data link. The flight-deck automation counts on the availability of advanced navigation capabilities to execute the 4D trajectories with high timing precision. Several publications have documented the SOAR concept and initial feasibility studies of the tower and flight-deck automation systems based on early experimental software prototypes of the automation functions. This paper reports on the latest development of the flight-deck automation system, including its clearance handling capabilities, guidance and control functions, pilot interface, conflict and incursion monitoring functions, as well as plans for the assessment of an experimental prototype implementation.

Flight Deck Procedural Guidelines for Datalink Trajectory Negotiations

Scipedia content — Wed, 03 Feb 2021 17:16:46 +0100

This paper presents an evaluation of three different flight deck procedures for their compatibility with a Trajectory-Based Operations Concept. Particular emphasis is placed on the interoperability of trajectory-based automation concepts and technologies with modern Flight Management Systems and datalink communication to enable negotiation between air and ground. A two-way datalink connection between the trajectory-based automation resident in the Center/TRACON Automation System and the Future Air Navigation System1 integrated Flight Management System/datalink in NASA Ames’ B747-400 Level D simulator has been established. Simulation experiments investigated the use of datalink messages to communicate strategic trajectories. A strategic trajectory is defined as an aircraft deviation needed to solve a conflict or otherwise modify a flight plan route and then merge the aircraft back to its nominal preferred trajectory using a single continuous trajectory clearance. A preliminary pilot-in-the-loop simulation evaluated two candidate procedures using a variety of horizontal and vertical trajectory clearances and found each to be feasible for basic datalink trajectory exchange. The procedure most preferred by the flight crews was adapted to enable trajectory negotiation and a second piloted simulation was conducted to measure important parameters that affect safety and efficiency. This simulation established that limited information exchange during trajectory negotiation between flight deck and ground based automation systems is feasible using current aircraft equipment and modified procedures, but that a number of factors relating to flight deck procedures are important to consider when constructing datalink clearances. Guidelines for designing flight deck-compatible clearances are presented along with the effect of several conditions on the crew’s message response time and the extent to which crews initiated negotiations. Among other results it was found that response times are generally shorter for vertical trajectories than horizontal, that prescribed minimum climb rates are difficult for crews to follow, and that basic negotiation using text-based messages requires little extra time than non-negotiated clearances.

1090 MHz channel capacity improvement in the Air traffic control context

Scipedia content — Wed, 03 Feb 2021 17:12:32 +0100

This paper is focused on the 1090 MHz SSR channel capacity increase by innovative transmission and decoding techniques. A lot of Air traffic control systems use the 1090 MHz channel: SSR downlink (on-board transponders), ADS-B messages, TIS-B, FIS-B. We focus the attention on the MLAT (multilateration) system, useful to localize and identify transponder-equipped targets (aircraft and vehicles). Today multilateration receiver stations have omni-directional antennae, so considering the aircrafts traffic and including the extension of surveillance to cooperating vehicles, the reception of super-imposed signals is more and more probable especially in high traffic density airports. In this paper we show the problem mitigation introducing a technique proposed in the international patent , and the decoding techniques proposed in and. We analyze the channel capacity improvement, then exploit the detection and the TOA estimation of the frequency-shifted and separated signals, and finally the EUROCAE requirements compliance.

DVFS in loop accelerators using BLADES

Scipedia content — Wed, 03 Feb 2021 17:08:38 +0100

Hardware accelerators are common in embedded systems that have high performance requirements but must still operate within stringent energy constraints. To facilitate short time-to-market and reduced non-recurring engineering costs, automatic systems that can rapidly generate hardware bearing both power and performance in mind are extremely attractive. This paper proposes the BLADES (Better-than-worst-case Loop Accelerator Design) system for automatically designing self-tuning hardware accelerators that dynamically select their best operating frequency and voltage based on environmental conditions, silicon variation, and input data characteristics. Errors in operation are detected by Razor flip-flops, and recovery is initiated. The architecture efficiently supports detection, rollback, and recovery to provide a highly adaptable and configurable loop accelerator. The overhead of deploying Razor flip-flops is significantly reduced by automatically chaining primitive computation operations together. Results on a range of loop accelerators show average energy savings of 32% gained by voltage scaling below the nominal supply voltage.

High-speed lines (HSL) as an environmentally friendly transportation system – the Polish case

Scipedia content — Wed, 03 Feb 2021 17:07:50 +0100

This paper describes how the rapid growth of passenger traffic in Poland and other European countries is mainly observed on the road. This situation produces a strong environmental impact. Internal air transport in Poland is practically non-existent. For internal connections this transport mode probably will not play an important role in the future. It follows that only the rapid rail network should be taken into account when looking at ways to decrease environmental impact. In this paper the basic results of the study on the high-speed railway network in Poland are presented. There are four basic corridors: two in the east–west and two in the north–south direction. As a first stage the Warszawa–Katowice/Krakow High-Speed Line (HSL) should be taken into account. This line may be considered as a part of the VI Pan European Corridor. In addition, the conventional railway line Warszawa–Radom–Kielce– Krakow/Katowice will be in the same corridor. The railway line Warszawa–Katowice/Krakow was designed as the main Polish line more than 30 years ago. The design speed was 250 km/h and – partly – 200 km/h. Now the maximum operational speed is 160 km/h only. The lack of adequate trains (especially locomotives) is one of the reasons for this situation. Amongst others are: the classical control system, the existence of 24-level crossings, etc. A detailed technical and economical study is now being carried out. The paper presents the basic results of investigation on the Warszawa–Katowice/Krakow high-speed line. As a conclusion further investigations on the HSL network in Poland are also described.

Evaluation of shared use of bicycles and pedestrians in Japan

Scipedia content — Wed, 03 Feb 2021 17:01:58 +0100

This paper the shared use of bicycles and pedestrians in Japan is from the proceedings of 14th International Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors reports that cycling on sidewalks in Japan was permitted beginning in 1978 after deregulation of the Road Traffic Law, which was passed to secure cyclists’ safety due to a lack of safe space in the roadways. Although bicycles are still regarded as a vehicle and when cyclists choose to use the roads they must follow the Road Traffic Law, many bicycle users prefer to use sidewalks. The authors outline the advantages and disadvantages of shared bicycle and pedestrian use of the sidewalks. Issues discussed include the safety and amenity of pedestrians, the reduction of cycling speed, and safety and freedom for utility cyclists, defined as the use of bicycles for going shopping or to school. The authors completed a video survey of shared use streets to analyze the relationship between cycling speed, frequency of hindrance and traffic density or traffic volume of street users. Their study results support the coexistence of bicycles and pedestrians with conditions including less than 0.5 pedestrians/minute/mile and less than 3.0 cyclists/minute/mile. The standard for pedestrian/bicycle share use in terms of hourly traffic volume was found to be less than 26 pedestrians/hour and 108 cyclists/hour for 2 meter-wide sidewalks.

Transient Reflection Analysis to Identify Problems with a Raw Water Pumping Main

Scipedia content — Wed, 03 Feb 2021 16:49:10 +0100

Transient analysis has been shown to have applications for the detection of discrete anomalies such as leakage, blockage and air pockets within pipelines. This technique may be extended to the investigation and assessment of the condition of pipelines. The issues associated with the field implementation of this technique, such as field measurement equipment, synchronization of measurements, lack of reliable system information, low pressures, the presence of air valves and operational issues also require further investigation. This paper presents the analysis of a raw water pumping main using field data collected during transient testing. This composite main of Acrylonitrile-Butadiene-Styrene (ABS) and Ductile Iron Cement Lined (DICL) pipe was designed to deliver 105 L/s and at the time of testing was capable of delivering only 87 L/s. Online and offline testing was undertaken with transients generated by the fast closure of a valve connected to the system via a standpipe. Both openings and closures of the valve were recorded, as were varying nozzle sizes. Online transients were also initiated by pump failures. A combination of transient and steady state analysis is used to determine the presence and location of anomalies within the pipeline with the aim to discover possible causes of the reduced flow capacity and assess the condition of the pipeline. An emphasis on the analysis of transient reflections, from system components and anomalies, is made including investigation of the consistency of results between openings and closures and varying nozzle sizes. The correspondence between reflection size and timing as measured at different locations is used to determine anomaly presence. Issues associated with applying this technique to a real world system are also investigated and discussed.

Development and evaluation of bus priority scenarios via microscopic simulation models

Scipedia content — Wed, 03 Feb 2021 16:35:16 +0100

The number of private vehicles increased dramatically during the last two decades in the island of Cyprus. This phenomenon had a negative effect on the bus transport mode which over the years its use has been considerably reduced. As traffic congestion increased considerably during the same period the need for a high quality public transportation system became clear. This need is also supported by the demand for public transportation by the aging and disadvantaged population. The best way to attract people back to public transportation is to have a reliable bus system with a high quality of service which can compensate for the lack of freedom and exibility a private vehicle can provide. However such a system should not have a negative effect on the traffic network in terms of congestion and travel times but should coexist serving both the needs of people who do not drive and those who use the public transport mode. The purpose of this paper is to present the development and evaluation of a number of scenarios aiming at attracting commuters back to public transportation. This idea stems from the fact that surveys among the Cypriot commuters show that people will use buses if buses provide a fast and reliable service. For this purpose, microscopic simulation models are developed in order to examine several scenarios of dedicated bus lanes and bus priority schemes so that the buses can provide the desired level of service with the minimal impact on the rest of the traffic. © 2009 IFAC. 434 441 "p"Sponsors: IFAC Technical Committee on Transportation Systems TC 7.4 Conference code: 85831 Cited By :3

Power-and-area efficient 14-bit 1.5 MSample/s two-stage algorithmic ADC based on a mismatch-insensitive MDAC

Scipedia content — Wed, 03 Feb 2021 16:26:56 +0100

IEEE International Symposium on Circuits and Systems, pp. 220 – 223, Seattle, EUA This paper presents a 14-bit 1.5 MSample/s two-stage algorithmic ADC with a power-and-area efficiency better than 0.5 pJmm2 per conversion. This competes with the most efficient architectures available today namely, ΣΔ and self-calibrated pipeline. The 2 stages of the ADC are based on a new 1.5-bit mismatch-insensitive MDAC and simulations demonstrate that a THD of –79 dB and an ENOB better than 12 bits can be reached without self-calibration.

Stochastic reachable sets of interacting traffic participants

Scipedia content — Wed, 03 Feb 2021 16:23:58 +0100

Knowledge about the future development of a certain road traffic situation is indispensable for safe path planning of autonomous ground vehicles or action selection of intelligent driver assistance systems. Due to a significant uncertainty about the future behavior of traffic participants, the prediction of traffic situations should be computed in a probabilistic setting. Under consideration of the dynamics of traffic participants, their future position is computed probabilistically by Markov chains that are obtained with methods known from hybrid verification. The characteristic feature of the presented approach is that all possible behaviors of traffic participants are considered, allowing to identify any dangerous future situation. The novel contribution of this work is the explicit modeling of the interaction of traffic participants, which leads to a more accurate prediction of their positions. Results are demonstrated for different traffic situations.

Decision support tool for predicting aircraft arrival rates from weather forecasts

Scipedia content — Wed, 03 Feb 2021 16:23:13 +0100

The principle bottlenecks of the air traffic control system are the major commercial airports. Atlanta, Detroit, St. Louis, Minneapolis, Newark, Philadelphia, and LaGuardia all expect to be at least 98% capacity by 2012. Due to their cost and the environmental and noise issues associated with construction, it is unlikely that any new airports will be built in the near future. Therefore to make the National Airspace System run more efficiently, techniques to more effectively use the limited airport capacity must be developed Air Traffic Management has always been a tactical exercise, with decisions being made to counter near term problems. Since decisions are made quickly, limited time is available to plan out alternate options that may better alleviate arrival flow problems at airports. Extra time means nothing when there is no way to anticipate future operations, therefore predictive tools are required to provide advance notice of future air traffic delays. This research describes how to use Support Vector Machines (SVM) to predict future airport capacity. The Terminal Aerodrome Forecast (TAF) is used as an independent variable within the SVM to predict Aircraft Arrival Rates (AAR) which depict airport capacity. Within a decision support tool, the AAR can be derived to determine Ground Delay Program (GDP) program rate and duration and passenger delay. Real world examples are included to highlight the usefulness of this research to airlines, air traffic managers, and the flying consumer. New strategies to minimize the effect of weather on arrival flow are developed and current techniques are discussed and integrated into the process. The introduction of this decision support tool will expand the amount of time available to make decisions and move resources to implement plans.

Low-power 6-bit 1-GS/s two-channel pipeline ADC with open-loop amplification using amplifiers with local-feedback

Scipedia content — Wed, 03 Feb 2021 16:18:35 +0100

IEEE International Symposium on Circuits and Systems, pp. 2258 – 2261, Seattle, EUA A low-power 1.2 V 6-bit 1-GS/s time-interleaved pipeline ADC designed in 130 nm CMOS is described. It is based on a new 2-channel 1.5-bit MDAC that performs openloop residue amplification using a shared amplifier employing local-feedback. Time mismatches between channels are highly attenuated, simply by using two passive front-end Sample-and-Hold circuits, with dedicated switch-linearization control circuits, driven by a single clock phase. Simulated results of the ADC achieve 5.35-bit ENOB, with 20 mW and without requiring any gain control/calibration scheme.

Optimizing network performance of computing pipelines in distributed environments

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

Supporting high performance computing pipelines over wide-area networks is critical to enabling large-scale distributed scientific applications that require fast responses for interactive operations or smooth flows for data streaming. We construct analytical cost models for computing modules, network nodes, and communication links to estimate the computing times on nodes and the data transport times over connections. Based on these time estimates, we present the efficient linear pipeline configuration method based on dynamic programming that partitions the pipeline modules into groups and strategically maps them onto a set of selected computing nodes in a network to achieve minimum end-to-end delay or maximum frame rate. We implemented this method and evaluated its effectiveness with experiments on a large set of simulated application pipelines and computing networks. The experimental results show that the proposed method outperforms the streamline and greedy algorithms. These results, together with polynomial computational complexity, make our method a potential scalable solution for large practical deployments.

Planning for electric vehicles in Australia - Can we match environmental requirements, technology and travel demand?

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

Refereed/Peer-reviewed