Scipedia: Documents published in 2007

DEVELOPMENT OF A WIDE-VIEW VISUAL PRESENTATION SYSTEM AND ESTIMATING HUMAN PRIMARY VISUAL CORTICAL MAGNIFICATION BY USING FMRI FOR TRAFFIC SAFETY

Scipedia content — Mon, 22 Mar 2021 19:22:34 +0100

It is very important to understand human visual characteristics in the wide-view condition for traffic safety. In the present study, we focus on human basic visual characteristics of retinotopic mapping by using functional Magnetic Resonance Imaging (fMRI), and provide basic research results for traffic safety. Previous fMRI studies on human visual retinotopic mapping are typically used for central and/or peri-central visual field stimulus. The retinotopic characteristics on human peripheral vision are still not well known. In this study, we developed a new visual presentation system widest view (60 degrees of eccentricity). The wide-view visual presentation system was made from nonmagnetic optical fibers and a contact lens, so it can used in general clinical fMRI conditions and the cost is lower. In the present study, by using the newly developed wide view visual presentation system, we have firstly been able to gain success in the world to identify the human primary visual cortex (V1) with an eccentricity of 60 degrees and the quantitative relationship between V1 and peripheral visual field (eccentricity up to 60 degrees) by fMRI. In addition, we estimated the mean area for the V1 between 0–60 degree eccentricities, and acquired the areal cortical magnification function for V1 between 0–60 degree eccentricities was Mareal = 272/(E+1.44)2. The mean cortical surface area of V1 between the 0–60 degree eccentricities was about 2229 mm2. Our results have good agreement with using physiological, patient and anatomical measurements. From the results of the present study, it is explained why traffic accidences easily take place on crossings. In the human brain visual cortex (V1), only a small cortical area is used to process visual information from the peripheral visual field. The basic results suggest that drivers are unable to recognise the dangerous information from both sides of peripheral vision.

Document type: Article

Modeling, validation, and simulation of massive self-organizing wireless sensor networks with cross-layer optimization and congestion mitigation techniques

Scipedia content — Tue, 16 Feb 2021 13:02:24 +0100

TNO has formulated the ambition of founding a basis for the development of flexible multi-data source and multi-application (ad hoc) sensor networks. These networks are envisioned on a scale that is beyond networks for specific and separate sensor networks. These separate networks need in the future to be combined intelligently in order to assist users with real-time assessment during operations in challenging environments. For this, enabling technologies such as network architectures and model-based data-interpretation are being developed. In this context TNO has developed wireless sensor networks that consist of very small and cheap nodes. Each node can be the size of a golf ball and can run for a long time on an A4 battery. They are designed to be deployed on a massive scale (100-10k or larger). In the tactical environment they are typically lying on the ground. Because it is very difficult to test the performance of such deployments under realistic and controllable conditions, simulation is the only way to get insight in this. This paper focuses on how to study the performance of massive deployments of these sensor networks through simulation. It describes the modeling, validation and simulation of such networks. Features such as antenna patterns, radio propagation/path loss, terrain, medium access and transport protocols, routing, and simulation parallelization are discussed. Model validation experiments for the antenna pattern, the path loss propagation and communication performance for nodes lying on the ground will be discussed. It further describes the implementation of a promising energy aware MAC and transport protocol that are proposed in the literature and are suitable for congestion mitigation and cross-layer optimization. Results on timeliness of messages, bandwidth and power consumption are discussed. ©2008 IEEE.

A Queueing Framework for Routing Problems with Time-dependent Travel Times

Scipedia content — Tue, 16 Feb 2021 12:52:10 +0100

gning and scheduling vehicle routes in a dynamic environment is a crucial management problem. Despite numerous publications dealing with efficient scheduling methods for vehicle routing, very few addressed the inherent stochastic and dynamic nature of travel times. In this paper, a vehicle routing problem with time-dependent travel times due to potential traffic congestion is considered. The approach developed introduces the traffic congestion component based on queueing theory. This is an innovative modelling scheme to capture the stochastic behavior of travel times as it generates an analytical expression for the expected travel times as well as for the variance of the travel times. Routing solutions that perform well in the face of the extra complications due to congestion are developed. These more realistic solutions have the potential to reduce real operating costs for a broad range of industries which daily face routing problems. A number of datasets are used to illustrate the appropriateness of the novel approach. Moreover it is shown that static (or time-independent) solutions are often infeasible within a congested traffic environment which is generally the case on European road networks. Finally, the effect of travel time variability (obtained via the queueing approach) is quantified for the different datasets.

Aircraft noise pollution: a model of interaction between airports and local communities

Scipedia content — Tue, 16 Feb 2021 12:41:42 +0100

transport represents a dynamic and fast growing industry that fits well with the needs of nowadays society. The process of liberalization and deregulation in the air transport market introduced by the European Commission in the last decade, has deeply modified the structure of aviation at Community level. The growth in importance of carriers with a different economic structure along with the growth of regional airports are among the most important products of the changed scenario. Regional airports occupy a central role within the deregulated market since they represent preferred destinations for low-cost carriers and spokes for network carriers. However aviation represents a source of environmental externalities, especially at local level, which interferes with human activities. If on the one hand the impact of emissions at local level is under study and deserves a better understanding, on the other hand noise has always been a serious problem for dwellings located near the airports. Even if there has been a tremendous improvement in aircraft noise performances during the last twenty years the growth of the aviation market has outstripped this benefits. The enforcement of recent noise policies by the European Commission shifts the problem of noise impact from annoyance for people living near the airports to a constraint of airports growth. It is essential for airport operators to manage the variables that affect airport acoustical capacity in order to maximize the number of aircrafts that an airport can handle within a given noise level.

Prospective and limitations

Scipedia content — Tue, 16 Feb 2021 12:35:47 +0100

This article investigates the prospective and limitations in the application of potential intelligent transport system (ITS) functions to reduce accident risks, using a cause‐treatment relationship. The main causes of road accidents are described and appropriate ITS solutions (including advanced driver assistance systems and advanced traveller information systems) are presented as countermeasures. Anticipated impacts are discussed and indicate that several ITS have the potential of improving road safety and addressing specific accident causes. However, attention is required on particular aspects of their implementation as they may trigger adverse effects by imposing behavioural adaptation risks, and overestimation and over‐reliance on system capabilities. Further, user acceptability and strategic implementation issues are paramount to the successful introduction of these systems."br

Voluntary Carbon Offsetting Schemes for Aviation: Efficiency, Credibility and Sustainable Tourism

Scipedia content — Tue, 16 Feb 2021 12:24:31 +0100

Tourism is becoming increasingly dependent on air transport. Recent scientific work has pointed out the significant and growing contribution of air transport to greenhouse gas (GHG) emissions. Obligations to reduce GHG emissions under the Kyoto Protocol and post-Kyoto instruments might make transport more expensive or even restricted in the future. This paper examines these questions and the issues raised by the increasing number of organisations offering voluntary carbon offsetting schemes as a means of compensating for emissions of GHGs, mostly from transport, which could help to stabilise or reduce emissions. There are substantial differences between the approaches chosen by these organisations in terms of their calculation of emissions, compensation measures, price levels, company structures and evaluation processes. The paper discusses these differences and their consequences for the efficiency and credibility of voluntary carbon offsetting schemes. Within this increasingly contested area, there is general agreement that increased clarity and regulation is required.

Vectorial dislocation monitoring of pipelines by use of Brillouin-based fiber-optics sensors

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

In this paper, we propose and experimentally validate the use of a distributed optical fiber sensor for monitoring pipeline dislocation. The proposed technique is based on the measurement of the normal strain, by use of stimulated Brillouin scattering, along three longitudinal directions running along the pipeline. We demonstrate that, by choosing three lines reciprocally displaced by 120° around the circumference of the pipeline, it is possible to measure the amount and direction of pipeline dislocation. The longitudinal position at which the deformation occurs is also evaluated. The measurements achieved by using the proposed technique can be directly used to monitor the structural integrity of the pipeline, as well as to monitor the deformations of the rock/soil surrounding the pipeline. This can be of importance to monitor geological events. Numerical simulations carried out by the finite-element method have been employed to evaluate the accuracy of the measurements.

Towards nondestructive testing of pre-crash systems in a HIL setup

Scipedia content — Tue, 16 Feb 2021 12:11:26 +0100

Recently, the developments in the field of ADA systems shifted from comfort oriented systems to safety oriented systems. Consequently, the complexity of testing those systems increased. This leads to a demand for reproducible, efficient and safe testing methods for ADA systems in general, and pre-crash systems in particular. A method for pre-crash systems evaluation is presented, involving TNO's Vehicle Hardware-inthe-Loop facility (VeHIL) and its Crash Lab. This method, called VeHIL/Pre-crash, aims to support the development and verification of pre-crash systems, increasing the level of reproducibility, effectiveness and safety of the testing process. To this end, a test vehicle, positioned on a roller bench, is placed in a simulated traffic environment. In order to provide the test vehicle's environment sensor input, one of the simulated traffic participants is represented by a rail guided target vehicle, which is stopped by crumple tubes. Although the realization of this setup is not straightforward due to practical aspects such as high decelerations of the target and the challenge to establish a realistic sensory input in a confined environment, it is considered a promising development allowing for nondestructive testing of pre-crash systems in a hardwarein-the-loop setup. © 2008 IEEE.

Determining operating inlet pressure head incorporating uniformity parameters for multioutlet plastic pipelines

Scipedia content — Tue, 16 Feb 2021 12:07:38 +0100

WOS: 000256076400008

An important objective of a microirrigation system is to determine the proper operating inlet pressure head, ensuring the desired level of water application uniformity as well as the allowable pressure head variation along the multioutlet pipeline. This paper offers, simple, direct, but sufficiently accurate, relationships incorporating different microirrigation uniformity parameters, such as Christiansen uniformity coefficient, coefficient of variation of emitter discharge, and allowable pressure head variation, to determine the operating inlet pressure head (i.e., pressure head and outflow profiles) for multioutlet plastic pipelines. In this analysis some mathematical expressions were deduced to relate three uniformity parameters; then the operating inlet pressure head is simply reformulated by taking into account a multiplying factor alpha to the required average outlet pressure head, in terms of three uniformity parameters. Resulting, the influence of different uniform pipe slopes on the water application uniformity and the operating inlet pressure head for various emitter discharge exponents, was evaluated. In addition, to cover various design combinations an extensive comparison between the proposed equations and those of the previous studies was also presented. Examination of the results from this research indicated that, the performance of the proposed technique is sufficient in comparison to those of the recent analytical and numerical procedures.

Admission of QoS aware users in a smart network

Scipedia content — Tue, 16 Feb 2021 11:59:05 +0100

Smart networks have grown out of the need for stable, reliable, and predictable networks that will guarantee packet delivery under Quality of Service (QoS) constraints. In this article we present a measurement-based admission control algorithm that helps control traffic congestion and guarantee QoS throughout the lifetime of a connection. When a new user requests to enter the network, probe packets are sent from the source to the destination to estimate the impact that the new connection will have on the QoS of both the new and the existing users. The algorithm uses a novel algebra of QoS metrics, inspired by Warshall's algorithm, to look for a path with acceptable QoS values to accommodate the new flow. We describe the underlying mathematical principles and present experimental results obtained by evaluating the method in a large laboratory test-bed operating the Cognitive Packet Network (CPN) protocol.

Analytical Relationships for Designing Multiple Outlets Pipelines

Scipedia content — Tue, 16 Feb 2021 11:49:19 +0100

WOS: 000245159300007

In this paper an analytical procedure taking into account the nonuniform outflow profile for hydraulic analysis and design of multiple outlets pipelines, is presented. Energy relations are improved based on the average friction drop approach with a simple exponential function, to express the nonuniform outflow concept. To determine friction head losses, the Darcy-Weisbach formula is used here; and the kinetic head change is considered whereas minor head losses are neglected. Several mathematical relationships are also derived for computing extreme pressure heads and their locations of occurrence along the pipeline. The presented method also provides specific lengths of the segments in which the different flow regimes occur along its length. This method simulates pressure and outflow profiles along trickle and sprinkler irrigation laterals and manifolds, as well as gated pipes. The presented technique was applied to several computational examples to clarify its precision for trickle and sprinkler lateral design and the analytical results were compared with those obtained using the numerical step-by-step method. The comparison test for the various design combinations indicated that, the proposed method is found to be sufficiently accurate in all design cases for both trickle and sprinkler lateral design. The analytical development is simple, direct, and easily adaptable to solve hydraulic design problems of various types of single-diameter mutiple-outlet pipelines in different flow regimes and uniform line slope cases. It is preferred to the numerical techniques which need large amounts of execution time and complex computer operations.

Online energy management for hybrid electric vehicles

Scipedia content — Tue, 16 Feb 2021 11:21:29 +0100

Hybrid electric vehicles (HEVs) are equipped with multiple power sources for improving the efficiency and performance of their power supply system. An energy management (EM) strategy is needed to optimize the internal power flows and satisfy the driver's power demand. To achieve maximum fuel profits from EM, many solution methods have been presented. Optimal solution methods are typically not feasible in an online application due to their computational demand and their need to have a priori knowledge about future vehicle power demand. In this paper, an online EM strategy is presented with the ability to mimic the optimal solution but without using a priori road information. Rather than solving a mathematical optimization problem, the methodology concentrates on a physical explanation about when to produce, consume, and store electric power. This immediately reveals the vehicle characteristics that are important for EM. It is shown that this concept applies to many existing HEVs as well as possible future vehicle configurations. Since the method only focuses on typical vehicle characteristics, the underlying algorithm requires minor computational effort and can be executed in real time. Clear directions for online implementation are given in this paper. A parallel HEV with a 5-kW integrated starter/generator (ISG) is selected to demonstrate the performance of the EM strategy. Simulation results indicate that the proposed EM strategy exhibits similar behavior as an optimal solution obtained from dynamic programming. Profits in fuel economy primarily arise from engine stop/start and energy obtained during regenerative braking. This latter energy is preferably used for pure electric propulsion where the internal combustion engine is switched off. © 2008 IEEE.

Editorial

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

Infections are a frequent consequence of natural disasters. Repatriated victims may require hospital care due to multiple fractures, pneumonia or wound infections caused by multi-resistant pathogens that require specific infection control measures. To address potential pitfalls of infection control and clinical care in repatriated patients, we sought to provide microbiological insight into the possible origins of multi-drug antibiotic resistance in survivors of natural disasters. A review of the medical literature was performed from 1986 to 2006 with an emphasis on the 2004 tsunami disaster in the Indian Ocean. After natural disasters, polymicrobial infections may occur following heavy inoculation during trauma. Multi-resistant Gram-negative pathogens are more prevalent than Gram-positive bacteria. A high incidence of extended spectrum beta-lactamase-producing bacteria and difficult-to-treat fungal infections in otherwise immunocompetent hosts may challenge routine hospital care. We recommend that survivors of natural disasters should be kept in pre-emptive contact isolation during air transport and hospitalisation until the results of all microbiological cultures become available. A meticulous diagnostic work-up is necessary upon admission and empiric antibiotic treatment should be avoided. Infections may also become manifest after several weeks of hospitalisation. In case of life-threatening infection, antibiotic therapy should cover non-fermenting pathogens.

Transient Heat Transfer from an Offshore Buried Pipeline during Start-up Working Conditions

Scipedia content — Tue, 16 Feb 2021 11:13:57 +0100

The 2D heat transfer from offshore, completely buried pipelines is studied with reference to transient working conditions. In particular, the start-up case is considered (i.e., the case of a pipeline initially at equilibrium with the surrounding soil). Two different start-up cases are investigated: the step-rising case and the smooth-rising case. (In the latter, the steady-state wall temperature is reached in a finite time.) The energy balance equation is written in a dimensionless form and solved numerically by means of a finite element method. The dimensionless temperature field in the soil and the thermal power exchanged per unit length by the pipeline with the soil are determined. A comparison with a simpler one-dimensional model of the phenomenon (“extra-soil layer” approximation) is performed.

Effects of recommendations

Scipedia content — Tue, 16 Feb 2021 11:12:59 +0100

The provision of travel information may serve as a means of changing the behavior of individual travelers in ways that are beneficial to the transportation system at large. On the basis of the argument that a better understanding of travel behavior in the presence of traffic information is required, this paper reports on the analysis of a computer experiment investigating the effects of recommendations with different underlying control objectives on route choice under uncertainty. The results indicate that when potential congestion is anticipated, travelers use the recommendations provided as an indicator of the choices of other travelers as they conjecture the rate of compliance to reduce the uncertainty when they make decisions.

An exploratory analysis of reverse logistics in Flanders

Scipedia content — Tue, 16 Feb 2021 10:55:25 +0100

This paper reports on a reverse logistics survey of shippers and logistics service providers in Flanders, one of the leading logistics regions in Europe. We characterise the reverse logistics activities with respect to return reasons, recovery options, outsourcing, lifecycle length and value of products. Practically all the respondents have to deal either with shortlife cycle or low-value products, or both, stressing the importance of efficient reverse logistics handling. Yet, in spite of the increasing attention that reverse logistics is receiving in management literature, its full potential still appears to be under exploited in practice. Respondents consider reverse logistics processes to be out of control, especially for packaging and support materials and still with relatively modest management attention. In addition, we assess the future outlook and potential growth. Almost all companies expect an increase of management attention for reverse logistics, and the results show a large potential with respect to third party service providers, including decision support tools in this area. Furthermore, we examine the underlying causes of the relatively low reverse logistics performance and point out issues that need improvement.

Testing for Economies of Scope in European Railways:An Efficiency Analysis

Scipedia content — Tue, 16 Feb 2021 10:50:00 +0100

In this paper, we conduct a pan-European efficiency analysis to investigate the performance of European railways with a particular focus oil economics of vertical integration. We test the hypothesis that integrated railways realise economies of scope and, thus, produce railway services with a higher level of efficiency. To determine whether joint or separate production is more efficient, we apply a data envelopment analysis super-efficiency bootstrapping model which relates the efficiency for integrated production to a reference set consisting of separated firms which Use a different production technology. We find that for a majority of European railways, economics of scope exist.

Evaluation of Ankara - Istanbul high speed train project

Scipedia content — Tue, 16 Feb 2021 10:36:50 +0100

Many countries have been carrying out some changes in their transportation policies for the sake of environmental and economical considerations. These circumstances have also affected Turkey to change the national transportation policies. In this study, transportation policies of Turkey have been investigated and, in this context, an important railway project of Ankara - Istanbul line has been analyzed. In evaluation, the present condition of the rail line, high speed train project is compared in terms of market study, technological and economical point of views. Finally, conclusions and suggestions are presented. © 2007 Taylor & Francis Group, LLC. All rights reserved.

Uncertainties in risk assessment of CO2 pipelines

Scipedia content — Tue, 16 Feb 2021 10:31:57 +0100

The main goal of this study is to identify knowledge gaps and uncertainties in Quantitative Risk Assessments (QRA) for CO2 pipelines and to assess to what extent those gaps and uncertainties affect the final outcome of the QRA. The impact of methodological choices and uncertain values for input parameters on the results of QRA’s have been assessed through an extensive literature review and by using commercially available release, dispersion and effect models. It is made apparent that over the full life cycle of a QRA knowledge gaps and uncertainties are present that may have large scale impact on the accuracy of assessing risks of CO2 pipelines. These encompass the invalidated release and dispersion models, the currently used failure rates, choosing the type of release to be modeled and the dose-effect relationships assumed. Also recommendations are presented for the improvement of QRA’s for CO2 pipelines.

Managing traffic by privatisation of road capacity: a property rights approach

Scipedia content — Tue, 16 Feb 2021 10:03:09 +0100

Road congestion remains a serious problem, despite all the efforts to limit road use and to manage growing road traffic volumes. Economic approaches (such as pricing) are introduced based on traditional welfare economic theory. Although they are sometimes very successful, the magnitude of traffic issues also requires alternative and unconventional approaches. Perhaps a more innovative perspective is needed. The paper discusses an alternative economic approach starting from property rights theory. It is translated in transport systems in concepts of infrastructure capacity slot management, where slots are dynamically priced and exclusively allocated to individual users. Debates and practices regarding this approach in air traffic and rail traffic are further developed than in the field of road traffic. The paper aims to explore the potential benefits and disadvantages of the property rights approach for road traffic. Attention is paid to major institutional and technical conditions. The conclusion is that the approach theoretically has clear advantages and seems technologically feasible. Nevertheless, serious political and institutional issues have to be solved first.

Promoting bike-and-ride: the Dutch experience

Scipedia content — Tue, 16 Feb 2021 10:02:50 +0100

The number of policy initiatives to promote the use of bike-and-ride, or the combined use of bicycle and public transport for one trip, has grown considerably over the past decade as part of the search for more sustainable transport solutions. This paper discusses the experiences with, and impacts of, such initiatives in the Netherlands. The Dutch measures to promote bicycle use in access trips have been generally successful. A country-wide program to upgrade regular and secure bicycle parking at train stations has led to an increase in user satisfaction and a growth in bicycles parked at stations. Smaller programs to stimulate the combined use of bike-and-bus have resulted in an increase in bicycle use, bus use, and share of infrequent bus passengers. Bicycle lockers at bus stops are hardly used by bus passengers, due in part to the dominance of students among bus users as well as the relatively high price of lockers in comparison to the value of bicycles used for access trips. Measures to promote the use of the bicycle in egress trips have met with more varying results. Projects to introduce leasing bicycles for egress trips have failed to attract passengers, for both train and bus services. In contrast, the introduction of flexible rental bicycles at train stations has resulted in a small reduction in car use, growth in train trips, and growth in bicycle use for non-recurrent trips. The Dutch experiences suggest some lessons for promoting bike-and-ride in countries and cities with a less well-developed bicycle infrastructure.

A Matching Model for the Backhaul Problem

Scipedia content — Tue, 16 Feb 2021 09:58:06 +0100

The 'backhaul problem' is characterized by an imbalance in transport flows between locations. This problem is usually studied in a perfectly competitive framework, which essentially predicts that when the imbalance is sufficiently large, the freight price of transport from low demand regions to high demand regions, the so-called backhaul price, drops to zero. This result is inconsistent with empirical observations. In this paper, we develop a matching model to address this inconsistency. We argue that market friction, through search imperfections due to lack of information by carriers on the (future) demand for transport by customers, may play an important role in the determination of backhaul prices. We demonstrate that carriers are at least compensated for the time they search for customers, so the backhaul price is in general positive. The matching model is numerically applied to the inland navigation shipping market in the Rhine river area in Western-Europe. We also analyse the effects of increases in transport costs on transport flows and backhaul prices, e.g. due to climate changes.

RESEARCH INTO INTELLIGENT TRANSPORT SYSTEMS (ITS) TECHNOLOGIES AND EFFICIENCY

Scipedia content — Mon, 15 Feb 2021 12:23:24 +0100

Intelligent Transport Systems work with information and control technologies which provide the core of ITS functions. Some of these technologies, like loop detectors, are well known to transportation professionals. However, there are a number of less familiar technologies and system concepts that are the key to ITS functions. The technical core of ITS is information and control technologies, but human factors are also vitally important, and potentially very complex. This paper introduces the main ITS enabling technologies and explains why transport professionals should involve human factor experts at an early stage of design of ITS equipment and facilities. First Published Online: 27 Oct 2010

Document type: Article

Research and Development Work on Lithium-ion Batteries for Environmental Vehicles

Scipedia content — Mon, 15 Feb 2021 10:51:22 +0100

Interest in electric vehicles (EVs) and hybrid electric vehicles (HEVs) has risen dramatically on account of environmental and energy concerns. The biggest issues that must be addressed in order to popularize these advanced vehicles are related to the battery.We have been promoting vigorous R&

D work on batteries for application to environmental vehicles since the beginning of the 1990s. Attention was focused on lithium-ion batteries early on as a fundamental solution to the critical issue mentioned above. The conclusion was reached that the development of those potentialities to their fullest extent would create completely new forms of value unobtainable with conventional batteries. As a result of extensive theoretical studies and many experimental demonstrations, we successfully showed ahead of others that those potentialities did in fact exist and could be achieved.This paper makes clear the various performance requirements of advanced batteries for EV or HEV application, focusing in particular on the critical aspects of the battery thermal design and construction for system stability. It also explains how the power output of the lithium-ion battery has been substantially improved for application to HEVs.

Document type: Article

THE INFLUENCE OF URBAN LAND USE ON PEDESTRIANS CASUALTIES

Scipedia content — Fri, 12 Feb 2021 16:15:36 +0100

This study investigates how urban land use affects pedestrian and bicyclist casualties in children, adults, and elderly, and takes into account both people killed or seriously injured (KSI) and minor casualties. The study took into account ages of pedestrians and urban land use patterns, not traffic flow. The study used governmental United Kingdom land use classifications and separate models for different times of day, as pedestrian traffic varies during working and non-working hours. Land use data, casualty data, and population density data were taken from Newcastle upon Tyne and analyzed. The study found that most causalities involved adult pedestrians during non-working hours, and suggests that attention be paid to the number, location, and open hours of retail outlets in order to reduce the incidence of traffic accidents.

Document type: Article

Transport systems and policies for sustainable cities

Scipedia content — Fri, 12 Feb 2021 14:49:30 +0100

The 20th century witnessed revolutionary developments in transportation technology with major impacts on the form and character of cities. Progress in increasing mobility has brought many benefits as well as serious problems, particularly in deterioration of livability and sustainability. Increase in auto ownership led to serious problems of chronic traffic congestion. Attempts to rebuild cities to provide full accommodation of private cars have led to serious problems of auto dependency and deterioration of cities. Experiences from recent decades have shown that urban transportation is much more complex than usually realized. Livable and sustainable cities require policies that lead to creation of a transportation system consisting of coordinated public transit and private cars, and encourages pedestrian environment and efficient, sustainable development. Great need for better understanding of the complex problems in implementing incentives and disincentives aimed at achieving intermodal balance is emphasized. Brief descriptions of cities which lead in achieving such livable conditions is followed by a summary of lessons and guidelines for the future.

Document type: Article

Revisión. Supervisión de transportes intermodales de frutas mediante redes de sensores

Scipedia content — Fri, 12 Feb 2021 14:24:11 +0100

Most of the fruit in Europe is transported by road, but the saturation of the major arteries, the increased demand for freight transport, and environmental concerns all indicate there is a need to change this means of transport. A combination of transport modes using universal containers is one of the solutions proposed: this is known as intermodal transport. Tracking the transport of fruit in reefer containers along the supply chain is the means by which product quality can be guaranteed. The integration of emerging information technologies can now provide real-time status updates. This paper reviews the literature and the latest technologies in this area as part of a national project. Particular emphasis is placed on multiplexed digital communication technologies and wireless sensor networks.

La calidad de los productos hortofrutícolas adquiere cada día más importancia. En la Unión Europea la mayor parte de la fruta es transportada en camiones, pero la congestión de la principales carreteras, el aumento de la demanda de transporte de mercancías, estimado en un 38% para los próximos 10 años, y los problemas medioambientales que de ello se derivan hacen necesario modificar los procedimientos de transporte. El transporte intermodal puede ser preciso, flexible y más respetuoso con el medio ambiente. Para asegurar la calidad de las frutas es imprescindible realizar un seguimiento y garantizar la trazabilidad de las mismas durante su transporte a lo largo de la cadena de suministro. Un sistema que integre diferentes tecnologías emergentes puede informar en tiempo real del estado de la carga. Este artículo hace una revisión de las últimas publicaciones y tecnologías aparecidas y recoge una propuesta de desarrollo de una red de sensores en un contenedor frigorífico mediante redes inalámbricas de sensores, buses de campo y sensores inteligentes. También se expone una propuesta de especificaciones para un sistema de supervisión multidistribuido de frutas y hortalizas mediante diferentes sensores y dispositivos electrónicos.

Document type: Article

Transportation Bipolar Ni-MH Battery

Scipedia content — Fri, 12 Feb 2021 12:36:21 +0100

novel bipolar packaging design for a nickel metal hydride (NiMH) battery has been developed. As with other bipolar designs, advantages include reduced battery resistance and volume when compared with more conventional approaches. These advantages make the bipolar NiMH an excellent energy and power source for existing and emerging high voltage, high power applications. In this paper, we give an account of our recent experiences with the design, with a focus on designs for high power batteries for hybrid electric vehicles and high energy batteries for plug-in hybrids. In addition, we discuss results from a hybrid electric vehicle to plug-in hybrid electric vehicle conversion utilizing a high energy bipolar NiMH battery. The conversion and results demonstrate the successful implementation of the battery design in an automotive application.

Document type: Article

Impact of Employer Based Programs on the Transit System Ridership and Transportation System Performance

Scipedia content — Thu, 11 Feb 2021 14:11:31 +0100

This document reports on a study that established a direct quantitative relationship between employer-based Transportation Demand Management (TDM) strategies and the performance of a transportation system. The study objectives were to develop a methodology for measuring the impacts of employer-based TDM programs on the performance of a traffic network using measures universal to traffic operations staff, transportation planners, and decision-makers. The study used a microsimulation traffic model to simulate the effects of Washington State Commute Trip Reduction (CTR) programs implemented by 189 employers in an 8.6-mile segment of I-5 in the Seattle downtown area. The current performance of the selected network with the actual volumes provided by the Washington State Department of Transportation (Scenario With TDM) was compared to that of a scenario with vehicle trips actually reduced by CTR programs at the worksites added onto the network (Scenario Without TDM). Performance measures analyzed included the spatial and temporal extent of congestion, recurring delay, speed, and travel time. On the segment of I-5 in the study area, savings in AM peak delay due to CTR programs were 152,489 vehicle minutes and 17,297 vehicle miles of travel were reduced. Savings in PM peak delay were 169,486 vehicle minutes and 14,510 vehicle miles were reduced. Fuel saved in the AM and PM peak were 3,489 and 4,314 gallons, respectively. The study proved that TDM programs have a significant impact on the operation of the transportation network. Further sensitivity analysis proved that even a small reduction in vehicle trips at worksites (assuming as little as 4 percent with non-regulatory programs) had a significant impact on the performance of the transportation network decreasing delay in vehicle-minutes by as much as 21.9 and 32.3 percent during the AM and PM peak periods, respectively.

Road Pricing, the Economy and the Environment

Scipedia content — Mon, 08 Feb 2021 12:30:20 +0100

It is often claimed that many drivers use their private car rather habitually. The claim gains credibility from the fact that travelling to many everyday destinations fulfils all the prerequisites for habit formation: it is recurring, performed under stable circumstances and produces rewarding consequences. Since the decision is made quite automatically and only one choice alternative is considered (the habitually chosen one), behaviour guided by habit is difficult to change. The implications of car use habits for converting drivers to commuters using public transportation is analysed based on a survey undertaken in the Copenhagen area. The study reveals that a relatively low percentage of drivers (10-20%) consider commuting by public transportation in the near future, which is hardly a surprise. A hierarchical analysis, where reported use of public transportation is regressed on intentions to do so, car use habit, and the interaction between the two, confirms the theory-derived hypothesis that car use habits act as an obstacle to the transformation of intentions to commute by public transportation into action. It is often claimed that many drivers use their private car rather habitually. The claim gains credibility from the fact that travelling to many everyday destinations fulfils all the prerequisites for habit formation: it is recurring, performed under stable circumstances and produces rewarding consequences. Since the decision is made quite automatically and only one choice alternative is considered (the habitually chosen one), behaviour guided by habit is difficult to change. The implications of car use habits for converting drivers to commuters using public transportation is analysed based on a survey undertaken in the Copenhagen area. The study reveals that a relatively low percentage of drivers (10-20%) consider commuting by public transportation in the near future, which is hardly a surprise. A hierarchical analysis, where reported use of public transportation is regressed on intentions to do so, car use habit, and the interaction between the two, confirms the theory-derived hypothesis that car use habits act as an obstacle to the transformation of intentions to commute by public transportation into action.

Decentralised Progressive Signal Systems for Organic Traffic Control

Scipedia content — Mon, 08 Feb 2021 12:29:18 +0100

n increased mobility and the resulting rising traffic demands lead to serious congestion problems in many cities. Although there is not a single solution that will solve traffic congestion and the related environmental and economical problems, traffic light coordination is an important factor in achieving efficient networks. This paper presents a new distributed approach for dynamic traffic light coordination that relies on locally available traffic data and communication among neighboring intersections. The coordination mechanism is combined with an organic traffic control approach to form an adaptive, distributed control system with learning capabilities. The efficiency of the resulting organic system is demonstrated in a simulation-based evaluation.

Interdependence of dynamic traffic flows

Scipedia content — Mon, 08 Feb 2021 10:14:08 +0100

End-to-end (e2e) quality of service (QoS) is the key target to be achieved in order to successfully support high quality real-time services. While ISDN, SDH and ATM provide service classes that natively support constant bit-rate transmission tunnels, i.e. provide circuit switching that offers constant bandwidth for the entire duration of a service, packet switched technologies natively do not provide that option. The economically irreversible migration to the Internet protocol (IP) as transport plane for all kinds of services necessitates sophisticated traffic engineering to fulfil the basic service demands of real-time services being low latency, fast round-trip times (RTT), negligible jitter and minimal loss-rate. Most of the current approaches to optimise IP routing for real-time services target firstly at admission control and secondly on node internal priority scheduling. In this study we focus on the second part and try to evaluate the problems that arise when such node internal mechanisms get cascaded along a path, i.e. study the problems that need to be solved in order to derive e2e QoS from node performance in dynamic network scenarios. From the results mechanisms for dynamic admission control and priority scheduling in relation to current network and node state could be derived.

The Italian motorways of the sea system: current situation, policies and prospects

Scipedia content — Mon, 08 Feb 2021 10:06:54 +0100

The EU transport policy supports the development of the motorways of the sea (MOS) network as a priority axis of the Trans European Transport Network (TEN-T). In the general context of the EU transport policy and legislation, the Italian national authorities recognise the specific role of motorways of the sea links as one of the strategic action areas that can facilitate the mobility of freight. In this paper, the state of the art regarding the implementation of the MOS program in Italy is illustrated, with special regard to the services now in operation and the specific transport policy initiatives promoted by the Italian national authorities. Following the “Piano Generale della Mobilità”, published by the Italian Ministry of Transport in 2007, ports, together with airports and railway terminals, are included in the list of the so-called “international doors”, which are considered to be the most important nodes of the Italian transport network as a whole. The “Piano Generale della Mobilità” aims to encourage the development of synergies and to increase the level of integration between lo-lo and ro-ro services, which deploy more or less the same amount of capacity. In 2002 the Italian government promoted the so-called “Ecobonus” initiative. In 2004 it set up a new government-controlled company, Rete Autostrade Mediterranee (R.A.M.), with the specific task to support and co-ordinate actions for the development of motorways of the sea services at the national and European level. The Ecobonus is an incentive that the Italian national authorities offer to the trucking community in order to shift traffic volumes from road to motorways of the sea routes involving Italian ports. The Ecobonus accounts for up to 30% of the price of the ticket and it is offered to those truckers who opt for the sea instead of the road, with a particular premium for truckers who reach a high number of trips/year (1600). This kind of premium aims also to enhance the pooling of small operators. Both national and EU routes to be promoted through the ecobonus initiative are identified by the Italian Law. In this work, for each Italian domestic and international scheduled MOS route, the operator, the weekly frequency, the average travel time, the sea distance and the price have been identified and reported. Nowadays, traffic volumes on Italian MOS represent 5% of the total freight traffic volumes served by the Italian inland motorway system and an amount of 8% is the target-value expected for year 2011. A total amount of 460 return trips on 79 routes are operated by 39 companies. The average route length and the average speed are equal to 536 km and 34 km/h respectively. The most important operator that serves Italian ports with MOS lines is Grimaldi Group Napoli, which accounts for the 13% of the services in km per week. 24 Italian ports offer motorways of the sea services and Genoa, Ancona and Civitavecchia ports are the top three for km per week of scheduled MOS services. The price-distance functions for MOS services to/from Italian ports have been calculated, for a full-load 16-metre-long truck. The price rises, as travel distance increases. Nevertheleses, distance explains only a part of the variance of price with respect to a linear relationship between price and route length and actually prices strongly depend on the particular shipping company that operates the line. It can be noted that, actually, no Italian domestic continental motorways of the sea line is in operation yet, despite the Italian peninsula is characterised by two quite long “natural” motorways of the sea corridors like the Tyrrhenian and Adriatic Seas. Indeed, MOS will effectively succeed to determine a modal shift towards waterway transport, only if they provide services whose quality and competitiveness are comparable to road transport. Both the efficiency of ports and the cruise speed are crucial elements for MOS lines to compete against road-only transport.

Supply chain (re)design: support for managerial and policy decisions?

Scipedia content — Mon, 08 Feb 2021 10:04:57 +0100

A well-structured supply chain is of key importance in achieving efficient operations amongst the suppliers, manufacturers, distribution facilities and distribution channels that constitute the supply chain. The changing economic and political environment challenges multinational corporations to redesign their existing production and distribution network and to develop new strategies to meet customer service levels at lowest cost. This paper reviews the literature on supply chain design since 1999 with the objective of supporting the development of richer supply chain models capable of taking all logistics costs into account thereby optimizing the full cost of ownership for multinational corporations and allowing for a consolidation of value adding activities in high-wage regions.

Brillouin-based fiber-optics sensors for vectorial dislocation monitoring of pipelines

Scipedia content — Mon, 08 Feb 2021 09:51:15 +0100

Design and evaluation of a 4D interface for ATC

Scipedia content — Mon, 08 Feb 2021 09:46:37 +0100

The increasing complexity of Air Traffic System is pushing toward the development of innovative and more automated tools conceived to manage it. In this scenario an important role is assumed by HCI (Human Computer Interfaces) used by air traffic controllers and operators to visualize and interact with air traffic data. Currently, information about 3D scenery are displayed with a two-dimensional representation. This paper presents the design, development and evaluation of an innovative interface for ATC (Air Traffic Control) based on a 4D (3D space + time) visualization display. The proposed interface allows the operator to perceive all the information, included meteorological conditions, useful for TWR/APP (ToWeR/APProach) control in a unique 4D synthetic reconstruction of the airport area. A particular attention is dedicated to the fourth variable, time, which is a fundamental parameter in ATC. A simple and fast trajectory prediction algorithm has been implemented in order to provide the operator with an effective “user assistance” tool in conflict detection activities. The interface has been evaluated performing test simulations and collecting results and useful advices for future developments by means of questionnaire

Reducing congestion in urban transport by using intermodal transport solutions

Scipedia content — Wed, 03 Feb 2021 22:02:15 +0100

The impact of cargo transport on the economy, society and environment has been defined and recognized as an essential element of the European integrations. The increase in the cargo transport share has raised also the density of traffic on the urban roads, which in turn raised the problem of traffic flows in the cities, congestion, traffic sustainability and environmental pollution. The past research related to solving the congestion problem in the cities was based on the tendencies to improve the entire transport system. One of the ways is to shift a certain volume of cargo from road to other transport branches, which results in the reduction of the number of heavy cargo vehicles on the roads, reduction of the adverse impact, i.e. use of intermodal transport which is more environmentally friendly and influences the increase of longevity and organization of urban and suburban traffic. Arguments supporting the mentioned hypotheses include: Interoperability as the basic precondition for the development of combined transport can be technical, functional, and market-oriented. Interoperability insures the continuous flow of cargo through the entire transport chain, and easier and faster transport of cargo and people through the urban areas (between the starting and end terminal or sender and receiver). Traffic infrastructure has to support the need for different modes of transport ; railtransport, road transport and water transport. Successful operation of combined transport (neutral to the mode of transport) requires the management of the entire transport chain (logistics), cargo control, so that cargo can be tracked at any moment, as well as the cargo safety in the transport chain.

Initial Implications of Automation on Dynamic Airspace Configuration

Scipedia content — Wed, 03 Feb 2021 21:54:58 +0100

The dynamic airspace configuration concept strives to remove today’s rigid structure of navigation aids, airways, pre-defined sectors of airspace, and special-use airspace to provide traffic managers with more flexibility to reconfigure airspace to address convective weather and meet fluctuations in user demand. The impact of increasing levels of air traffic management automation on controller workload and airspace capacity is analyzed. The automation levels represent a current operations baseline; seamless, integrated datalink operations; and automated airspace operations in which separation, merging and spacing guidance is provided for 33,000 ft and above without human controller involvement. Denver Center traffic and airspace for a good weather day are modeled to predict the effect of increased controller productivity on airspace configuration strategies. Results indicate that integrated datalink operations enable the high and low altitude feeder sectors for Denver arrivals to be combined into a single sector for the selected traffic demand, facilitating more uninterrupted descents than possible under current operations. Furthermore, results indicate automated airspace operations enable a single en route sector team to manage airspace below 33,000 ft that is a combination of 5 of today’s sectors.

A dynamic adaptive decision framework: integrating transport and land use measures aimed at traffic congestion reduction

Scipedia content — Wed, 03 Feb 2021 21:54:31 +0100

This paper describes how much has been written about the desperate need to seek alternative solutions to the urban traffic congestion problems that are faced today. In order to manage these problems three main streams of intervention have evolved from supply, demand and land use management paradigms. While their underlying measures all have the ability to reduce traffic congestion one way or another, little has been done to integrate the measures of each stream using a decision framework or process to facilitate the selection of site specific measures supporting local traffic and transport conditions. This paper reports the results of an empirical investigation by which a Multi-Criteria Analysis based dynamic adaptive decision framework was developed which screens through selected measures, identifying those that have the potential to alleviate site specific traffic congestion and transpose them into an integrated strategy. In assessing its usefulness and workability it was found to be capable of producing integrated strategies with the ability to manage traffic congestion, encourage sustainable development and alleviate some site specific development challenges.

Aerial Leak Detection for Significantly Improved Integrity Assurance

Scipedia content — Wed, 03 Feb 2021 21:50:54 +0100

BP gas production operations in North America manages over 15,000 miles of onshore pipelines that make up our vast, complex, and aging gas gathering networks. Surveying these for leaks presents a huge resource challenge using current ground based technology and, in turn, impacts the assurance of the safety and integrity of these operations. The Exploration and Production Technology Group evaluated new leak detection technologies using laser, thermal imaging camera and a high speed gas sampling detector that were deployed on aircraft and used global positioning systems coordinates to survey gas gathering pipelines. Field trials on gas gathering systems in the North Texas, Anadarko asset showed that the laser and gas sampling based leak detection systems were the most accurate, but the video imaging from the thermal camera made a powerful statement. Helicopters proved to be more suitable in leak detection surveys on gas gathering pipelines than that of fixed-wing aircraft. The aerial leak detection technologies produce a significant increase in efficiency and productivity in managing the integrity of BP’s gas gathering systems. While that improves business performance, perhaps more importantly is the fact that small gas leaks can be easily found before they become big ones. That reduces environmental damage and the potential for leaks to impact the public. The development and implementation of aerial leak detection in BP is being recognized as an integrity tool in providing a significantly improved integrity assurance to its gas gathering operations. A. Introduction The Exploration and Production Technology Group (EPTG) has worked closely with leading companies in the development of aerial gas leak detection technologies capable and suitable to the BP North America operations in gas production. Also potential applications lie in operations outside of North America as well as future capital projects. The safety and integrity of BP operations has become increasing important as the oil and gas industry has become closely watched and scrutinized by stakeholders, government agencies and the public. BP has been working diligently in providing assurance to its facilities and processes especially its gas gathering systems. BP strives to achieve its safety values where No Accidents, No Harm to People, and No Damage to the Environment within its operations. Several companies that were evaluated employing leading technologies in gas leak detection systems (LDS). Three different technologies for gas leak detection systems are laser, thermal camera, and sophisticated gas sampling based detection technologies and were tested in field trials. All of these technologies were installed on aircraft either helicopters or fixed-wing aircraft and can be deployed on the ground via vehicle mounted or hand held use. The remote detection capabilities of these technologies were attractive features that showed promise in using it on the BP gas gathering systems in order to meet its safety and integrity in the operation of gas gathering systems (GGS). B. Leak Detection Technologies The following technologies were reviewed: lasers, thermal camera and gas sampling based systems for leak detection systems (LDS). These hardware technologies have remote capabilities and can detect and locate leaks from a distance that can be deployed on fast moving aircraft giving them rapid measurement capabilities. There are obvious advantages in using aircraft compared to ground methods and will be discussed in the following section. Lasers (in the infrared wavelength) using light detection and radar (LIDAR) principles, similar to that of

Inter-Domain Path Computation using Improved Crankback Signaling in Label Switched Networks

Scipedia content — Wed, 03 Feb 2021 21:49:04 +0100

For label switched networks, such as MPLS and GMPLS, most existing traffic engineering (TE) solutions work in a single routing domain. These solutions do not work when a route from the ingress node to the egress node leaves the routing area or the autonomous system (AS) of the ingress node. In such cases, the path computation problem becomes complicated because of the unavailability of the complete routing information throughout the network. We present CWS (computation while switching), a new inter-domain path computation scheme which tries to compute a near-optimal path without assuming the availability of complete topology information. We provide a detailed comparison of the CWS scheme with another per-domain path computation scheme given in J.-P. Vasseur et al. (2006). Unlike the standard per-domain path computation scheme (Vasseur et al., 2006), the CWS scheme continues the quest for a better path instead of terminating the search at the first available path, resulting a significant improvement in terms of path optimality. In particular, CWS guarantees that, for a given network state, a computed inter-domain path will traverse a minimum number of domains. This improvement in path computation directly impacts the amount of traffic that can be allowed on the network. For example, for the COST266 topology with 28 domains and 37 bidirectional inter-domain links, CWS places 960 of the requested 2000 paths as compared to 683 paths placed by existing schemes. Finally, the path setup latency of the CWS scheme remains comparable to that of existing schemes, by allowing the data flow as soon as the first feasible path is found.

Participative processes for sustainable changes in European ATM and enabling methods within the SESAR context

Scipedia content — Wed, 03 Feb 2021 21:48:00 +0100

Safety Assessment of Autonomous Cars using Verification Techniques

Scipedia content — Wed, 03 Feb 2021 21:47:01 +0100

common requirement for autonomous cars is a safe locomotion which is evaluated by the method of hybrid verification applied online. The approach checks avoidance of static obstacles and dynamic traffic participants, which are described by imprecise data on their positions and velocities. The nonlinear dynamics of the autonomous car and other traffic participants is conservatively abstracted to Markov chains, which allows the efficient computation of their future positions probabilistically. The result is the probability of a crash for a given time horizon, showing if a given control strategy may lead to unsafe situations.

Robust Road Modeling based on a Hierarchical Bipartite Graph

Scipedia content — Wed, 03 Feb 2021 21:44:08 +0100

Driver assistance systems based on video processing deliver a number of warnings to the driver, such as lane departure, lane invasion by other vehicles, collision prediction, etc. This have been a field of intense research for many years, providing solutions based on road models where vehicles are afterwards detected and tracked. Robustness is essential in this field of road safety where outliers represent one of the major problems for road modeling. The motivation of this work is to provide a robust and, at the same time, flexible road model which identifies a variable number of lanes, their widths, the curvature of the road and the position of the vehicle in its lane. The major advantage of this model is that the system gives confidence measures for each lane, determining which lanes are actually present and which not. The model is structured as a hierarchical bipartite graph which simplifies information management, reduces sub-module dependencies and classifies elements of the road in different levels. At each level different strategies are applied, following four overall steps: measurement, estimation, evaluation and extrapolation, which lead to enhanced road model accuracy, reliability and flexibility. Several experimental results are provided, showing the robustness of the system, its stability and accurate results for large test paths.

Document type: Conference object

Robust Egress Interdomain Traffic Engineering

Scipedia content — Wed, 03 Feb 2021 21:43:28 +0100

BGP is traditionally configured to implement traffic engineering objectives without considering potential network dynamics. This might result in undesirable traffic distribution when network failures occur. In this paper, we present algorithms for interdomain traffic engineering that achieve the interdomain traffic engineering objectives under network failures. That is, we aim to configure routing policies so that traffic is distributed evenly. More importantly, the configuration is robust in the sense that it is able to achieve the specified traffic engineering goals despite network failures. We first investigate the coarse-grained robust configurations. The derived configuration can achieve optimal robust traffic engineering objectives for most network failures. Further, we develop a greedy algorithm to derive robust BGP configuration for any traffic distribution and link capacities. We use simulations to evaluate the robustness of the derived BGP configurations by applying the algorithm to both transit and stub ASs under realistic traffic demands. Our results show that the derived BGP configurations can improve the default configuration significantly in terms of achieving the robust traffic engineering objectives. Furthermore, our algorithm achieves robust traffic engineering goals without diminishing other routing objectives.

Traffic pollutant emissions in Barreiro city

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

Urban traffic is becoming a major problem, since most people use their own private car for all kind of trips, increasing the traffic congestion and atmospheric pollution. The purpose of this work was to study the atmospheric pollutants dispersion in Barreiro highway (IC21), in two specific situations, a traffic lights crossroad and a roundabout. The pollutants studied were traffic related pollutants, such as nitrogen oxides (NOx), particulate matter (PM) and CO (carbon monoxide). A traffic counting field campaign and particulate matter measurements were carried out in the light traffic crossroad and in the roundabout of the highway. Data from monitoring network stations was also collected. All this information was introduced in a dispersion model (ADMS-urban), to obtain a spatial simulation of the pollutants dispersion. Vehicle number, class and speed, fuel type, time of the day and urban street canyon were the traffic related parameters used by the model. Meteorological variables, such as wind speed and direction, relative humidity, temperature and heat flux were also taken into consideration to understand pollutant behaviour. The model results show the pollutants dispersion, on the IC21 highway, in two different meteorological scenarios: winter and summer. Winter seems to be the worst scenario for NOx and CO background concentrations, whereas PM tends to deposit due to rain, decreasing its concentration in this season. In summer, ozone (O3) concentration increases due to the photochemical reaction with some pollutants such as NOx. Analysing PM emissions, in the specific situations of light traffic crossroad and roundabout, on the IC21 highway, environmental advantages were found in the roundabout, despite its larger traffic flow, as it has a smaller PM concentration, even though it is above the legal limits.

OptiFlow - A Capacity Management Tool

Scipedia content — Wed, 03 Feb 2021 21:41:05 +0100

Intra-domain traffic engineering for routing protocols such as OSPF (open shortest path first) or intermediate system-intermediate system (IS-IS) can be performed by finding a judicious set of weights to allocate to the links of the network. Unfortunately, methods proposed in the literature for finding those weights may require a significant computational effort. By way of contrast, weight setting approaches based on linear programming can be shown in this paper to find suitable weights in the order of seconds. Prior to this time, it was necessary to determine appropriate weight settings in an off-line mode. From the results presented in this paper it can be demonstrated that solutions can be located for this problem in a matter of seconds. This makes it possible to perform traffic engineering for short term link overloads in real-time mode. The performance of this methodology has been verified by using simulation based on the well-known performance tool, ns-2. The technique described in this paper is being integrated into an optimisation module of a network capacity management tool called OptiFlow.

Implementation and Experimental Evaluation of On-Line Simulation Server for OSPF-TE

Scipedia content — Wed, 03 Feb 2021 21:36:54 +0100

the amount of traffic transfered on the Internet are increasing, dynamic Traffic Engineering (TE) becomes important to avoid link congestion. In Open Shortest Path Fast(OSPF)-based networks, link costs are statically set according to its long-term utilization for reducing traffic on some congested nodes, hence temporary performance degradation may occur due to short-term traffic fluctuation. For dynamic TE on OSPF-based networks, measurement of the utilization of links / nodes, inferring the set of link costs for improving transmission behavior and setting the cost set to routers are necessary and so-called On-Line Simulation (OLS) system can operate these functions autonomously and periodically. In this paper, we construct the server prototype in OLS system, and evaluate its scalability and control performance in our testbed network. Experimental results show that the server succeeds in providing low-cost network management and real-time control even if there is the large amount of traffic on the network. Furthermore, the total throughput over the network was greatly improved by the OLS.

7th International Conference on Hybrid Intelligent Systems (HIS 2007), 17-19 Sept. 2007, Kaiserlautern, Germany

Isotopic Identification Of Leakage Gas From Underground Storage Reservoirs- A Progress Report

Scipedia content — Wed, 03 Feb 2021 21:09:31 +0100

The Illinois State Geological Survey reports that in areas where bacteriogenic methane occurs in the near-surface groundwater, isotopic analysis of methane reliably distinguishes this gas from gas that has leaked from underground storage reservoirs. Bacteriogenic methane generally has an isotopic-carbon composition of -64 to -90 per mil, whereas the pipeline and reservoir gases analyzed thus far have all had isotopic-carbon compositions in the range of -40 to -46 per mil.

Low-Cost Protection for SER Upsets and Silicon Defects

Scipedia content — Wed, 03 Feb 2021 20:59:52 +0100

Extreme transistor scaling trends in silicon technology are soon to reach a point where manufactured systems will suffer from limited device reliability and severely reduced life-time, due to early transistor failures, gate oxide wear-out, manufacturing defects, and radiation-induced soft errors (SER). In this paper we present a low-cost technique to harden a microprocessor pipeline and caches against these reliability threats. Our approach utilizes online built-in self-test (BIST) and microarchitectural checkpointing to detect, diagnose and recover the computation impaired by silicon defects or SER events. The approach works by periodically testing the processor to determine if the system is broken. If so, we reconfigure the processor to avoid using the broken component. A similar mechanism is used to detect SER, faults, with the difference that recovery is implemented by re-execution. By utilizing low-cost techniques to address defects and SER, we keep protection costs significantly lower than traditional fault-tolerance approaches while providing high levels of coverage for a wide range of faults. Using detailed gate-level simulation, we find that our approach provides 95% and 99% coverage for silicon defects and SER events, respectively, with only a 14% area overhead.

Map-Based Precision Vehicle Localization in Urban Environments

Scipedia content — Wed, 03 Feb 2021 20:57:46 +0100

Many urban navigation applications (e.g., autonomous navigation, driver assistance systems) can benefit greatly from localization with centimeter accuracy. Yet such accuracy cannot be achieved reliably with GPS-based inertial guidance systems, specifically in urban settings. We propose a technique for high-accuracy localization of moving vehicles that utilizes maps of urban environments. Our approach integrates GPS, IMU, wheel odometry, and LIDAR data acquired by an instrumented vehicle, to generate high-resolution environment maps. Offline relaxation techniques similar to recent SLAM methods [2, 10, 13, 14, 21, 30] are employed to bring the map into alignment at intersections and other regions of self-overlap. By reducing the final map to the flat road surface, imprints of other vehicles are removed. The result is a 2-D surface image of ground reflectivity in the infrared spectrum with 5cm pixel resolution. To localize a moving vehicle relative to these maps, we present a particle filter method for correlating LIDAR measurements with this map. As we show by experimentation, the resulting relative accuracies exceed that of conventional GPS-IMU-odometry-based methods by more than an order of magnitude. Specifically, we show that our algorithm is effective in urban environments, achieving reliable real-time localization with accuracy in the 10centimeter range. Experimental results are provided for localization in GPS-denied environments, during bad weather, and in dense traffic. The proposed approach has been used successfully for steering a car through narrow, dynamic urban roads.

Classification of Weather Situations on Single Color Images

Scipedia content — Wed, 03 Feb 2021 20:54:28 +0100

Present vision based driver assistance systems are designed to perform under good-natured weather conditions. However, limited visibility caused by heavy rain or fog strongly affects vision systems. To improve machine vision in bad weather situations, a reliable detection system is necessary as a ground base. We present an approach that is able to distinguish between multiple weather situations based on the classification of single monocular color images, without any additional assumptions or prior knowledge. The proposed image descriptor clearly outperforms existing descriptors for that task. Experimental results on real traffic images are characterized by high accuracy, efficiency, and versatility with respect to driver assistance systems.

A model to reduce traffic, pollution and costs in urban distribution

Scipedia content — Wed, 03 Feb 2021 20:47:49 +0100

This paper presents a proposal to help metropolitan areas reduce traffic, pollution and also to cut delivery costs. The use of the collaborative logistics in the networking design for this fine distribution method shall allow the distribution partner to plan and execute deliveries, which will reducing the number of vehicles used in comparison with the regular distribution model (this also allows the use of a clean fleet of small vehicles – like electric minivans). The methodology used to develop the proposal is to simulate two different scenarios, comparing the variables that influence the traffic, the pollution emission and the cost involved with the distribution of goods in urban areas. Further to the variables considered in the study, this new model needs to prove its efficiency at service level. The conclusion of this study will compare those three variables between the regular model, where many different carriers need to reach the retail stores every day, delivering all kinds of products, with the proposed model, where only one carrier will do the deliveries in the urban areas.

TIE breaking: Tunable interdomain egress selection

Scipedia content — Wed, 03 Feb 2021 20:38:54 +0100

International audience; The separation of intradomain and interdomain routing has been a key feature of the Internet's routing architecture from the early days of the ARPAnet. However, the appropriate "division of labor" between the two protocols becomes unclear when an Autonomous System (AS) has interdomain routes to a destination prefix through multiple border routers—a situation that is extremely common to-day because neighboring domains often connect in several loca-tions. We believe that the current mechanism of early-exit or hot-potato routing—where each router in an AS directs traffic to the "closest" border router based on the intradomain path costs—is convoluted, restrictive, and sometimes quite disruptive. In this pa-per, we propose a flexible mechanism for routers to select the egress point for each destination prefix, allowing network administrators to satisfy diverse goals, such as traffic engineering and robustness to equipment failures. We present one example optimization prob-lem that uses integer-programming techniques to tune our mecha-nism to improve network robustness. Experiments with topology and routing data from two backbone networks demonstrate that our solution is both simple (for the routers) and expressive (for the net-work administrators).

Fatigue Life Prediction Due to Slug Flow in Extra Long Submarine Gas Pipelines

Scipedia content — Wed, 03 Feb 2021 20:33:39 +0100

Some offshore production fields require transporting of production fluids through very long submarines pipelines without a previous separation process. In the case of gas production, condensate will appear in the pipeline due to the pressure losses and low temperatures. For some production conditions a slug flow pattern may then develop in the pipeline, and because of the irregular sea bottom profile, there may be pipe unsupported spans of even hundreds of meters long. Therefore, slugs traveling in the pipeline will act as moving loads for the unsupported pipe, producing a dynamic response that in some cases might reduce the fatigue life of the pipeline. In this work, a finite element (FE) model of a pipeline transporting slugs has been developed and used to assess the fatigue life of a horizontal pipeline. Slug hydrodynamic characteristics have been obtained using Taitel & Barnea’s model. The structural FE model is based in Bernoulli beam elements where slugs, once they have been geometrically characterized, are input as moving loads traveling in the pipeline. The system dynamic response was calculated for different spans conditions and slugs characteristics corresponding to different gas-liquid ratios typical from gas field production conditions. Once a steady state condition was obtained in the dynamic response, mean and alternating stress levels were obtained for each analyzed case and introduced in fatigue formulae to obtain the fatigue life of the pipeline. Results show that for some production conditions and free span longitudes, fatigue life of pipeline may experience important reductions due to slug flow. These free spans are obviously most likely to happen in extra long submarines pipelines.Copyright © 2008 by ASME

Procedures and Issues of a Restrictive Runway Configuration at Dallas/Forth Worth International Airport

Scipedia content — Wed, 03 Feb 2021 20:33:27 +0100

This paper documents the Dallas/Fort Worth operations in northwest flow including the transition to and from this configuration, to shed some light on issues needing further attention. Documenting pilot and air traffic contro ller decision logic during these transitions can be used to create realistic air traffic models. While the Dallas/Fort Worth airport is the main subject for this paper, delays are seen at any airport where a restrictive runway configuration used during periods of non-prevailing winds. The two main sources of data were the quantitative flight data from the terminal area and en route airspace regions and insights into the qualitative decision-making proce ss provided by air traffic management subject matter experts. Archived flight data, such as aircraft tracks and landing runways, were used to plot aircraft approaches, holding patt erns, and vectoring. As expected, the primary factor in causing delay was the reduced number of runways. Secondary factors such as reduced approach precision and a high air t raffic controller workload arising from an uncommon runway configuration also contributed.

Improving Arterial Performance Measurement Using Traffic Signal System Data

Scipedia content — Wed, 03 Feb 2021 20:01:37 +0100

The characterization of the performance of freeways in real time and on a historical basis has been successfully achieved for many years. The ability to characterize arterial performance has been more elusive. Currently numerous applications of traffic management and traveler information systems include freeways but lack the ability to extend their operation to major arterials. This paper describes methods for quantifying arterial performance using data from signal system loop detectors. Included in the array of metrics are traffic density, total delay, predicted travel time, and signal coordination effectiveness. Methods for determining performance in these areas are adapted for use in quantitatively evaluating arterials in real time. To assess them, methods are employed to analyze archived data for a segment of Barbur Blvd. in Portland, Oregon. Suggestions for future research are also included.

Investigation of an AHP Based Multi Criteria Weighting Scheme for GIS Routing of Cross Country Pipeline Projects

Scipedia content — Wed, 03 Feb 2021 19:50:41 +0100

Pipelines are the most efficient, cost effective and environmentally friendly means of fluid transport [1]. When selecting the route of a cross country pipeline, the goal is to route it so that it has the greatest utility to the public while minimizing negative impacts to people and the natural environment. In order to accomplish this goal of addressing several factors, a large amount of location based information needs to be analyzed. Hence the manual routing processes are very tedious in nature. The advent of new techniques like that of Geographic Information System (GIS) has made the routing process of pipelines more systematic and effective. This work identifies the various factors which need to be considered while routing a pipeline in the Indian scenario. A GIS to represent the various factors and automatically route the pipeline has been developed. A main drawback in the system is the lack of a structured methodology to derive the relative preferences of the different factors affecting the route. To address this issue, an AHP based methodology was developed. The GIS and the AHP methodology have been tested on case studies in the Indian scenario.

Trajectory reconstruction techniques for evaluation of ATC systems

Scipedia content — Wed, 03 Feb 2021 19:46:51 +0100

This paper is focused on trajectory reconstruction techniques for evaluating ATC systems, using real data of recorded opportunity traffic. We analyze different alternatives for this problem, from traditional interpolation approaches based on curve fitting to our proposed schemes based on modeling regular motion patterns with optimal smoothers. The extraction of trajectory features such as motion type (or mode of flight), maneuvers profile, geometric parameters, etc., allows a more accurate computation of the curve and the detailed evaluation of the data processors used in the ATC centre. Different alternatives will be compared with some performance results obtained with simulated and real data sets.

Document type: Conference object

Microarchitecture parameter selection to optimize system performance under process variation

Scipedia content — Wed, 03 Feb 2021 19:46:37 +0100

Design variability due to within-die and die-to-die process variations has the potential to significantly reduce the maximum operating frequency and the effective yield of high-performance microprocessors in future process technology generations. This variability manifests itself by increasing the number and criticality of long delay paths. To quantify this impact, we use an architectural process variation model that is appropriate for the analysis of system performance in the early-stages of the design process. We propose a method of selecting microarchitectural parameters to mitigate the frequency impact due to process variability for distinct structures, while minimizing IPC (instructions-per-cycle) loss. We propose an optimization procedure to be used for system-level design decisions, and we find that joint architecture and statistical timing analysis can be more advantageous than pure circuit level optimization. Overall, the technique can improve the 90% yield frequency by about 14% with 3% IPC loss for a baseline machine with a 20FO4 logic depth per pipestage. This approach is sensitive to the selection of processor pipeline depth, and we demonstrate that machines with aggressive pipelines will experience greater challenges in coping with process variability.

Strain-Based Design Methods for Composite Repair Systems

Scipedia content — Wed, 03 Feb 2021 19:44:36 +0100

Composite materials are commonly used to repair corroded and mechanically-damaged pipelines. Most of these repairs are made on straight sections of pipe. However, from time to time repairs on complex geometries such as elbows, tees, and field bends are required. Conventional design methods for determining the amount of required composite materials are not conducive for these types of repairs. Over the past several years, the author has developed a methodology for assessing the level of reinforcement provided by composite materials to damaged pipelines using finite element methods. Instead of stress as the design basis metric, the method employs a strain-based design criteria that is ideally-suited for evaluating the level of reinforcement provided to non-standard pipe geometries. The finite element work has been validated using experimental methods that employed strain gages placed beneath the composite repair to quantify the level of reinforcement provided by the repair. This paper provides a detailed description of the strain-based design method along with appropriate design margins for both the reinforced steel and long-term performance of the composite materials.Copyright © 2008 by ASME

Updating demand vectors using traffic counts on congested networks: a real case application

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

the elements of a transportation system model generally suffer from some approximation. Normally the demand vector is considered the most crucial and problematic element to be simulated, and traffic counts are thus generally used to update it so that the whole model system is able to reproduce the observed link flows. Updating demand vectors using traffic counts has received considerable attention in recent years. In this paper the methodology proposed by Cascetta and Postorino (Fixed point models for the estimation of O-D matrices using traffic counts on congested networks. Transportation Science, Vol. 35, 2001) for updating the demand vector using traffic counts on congested networks is applied to a real case: the OD demand vectors for the city of Naples (Italy). The results show the good capacity of this methodology to reproduce the traffic counts measured. Furthermore, through the estimated OD vectors it was possible to make a structural analysis of transportation demand in Naples. Keyword: origin-destination demand updating; bi-level programming problem; transportation simulation model.

Modelling Environmental and Economic Impacts of Aviation: Introducing the Aviation Integrated Modelling Project

Scipedia content — Wed, 03 Feb 2021 19:19:32 +0100

The Aviation Integrated Modelling project is developing a policy assessment capability to enable comprehensive analyses of aviation, environment and economic interactions at local and global levels. It contains a set of inter-linked modules of the key elements relevant to this goal. These include models for aircraft/engine technologies, air transport demand, airport activity and airspace operations, all coupled to global climate, local environment and economic impact blocks. A major benefit of the integrated system architecture is the ability to model data flow and feedback between the modules. Policy assessment can be conducted by imposing policy effects on the upstream modules and following implications through the downstream modules to the output metrics, which can then be compared to a baseline case. A case study involving different evolution scenarios of the US air transportation system from 2000 to 2030 is used to show the importance of feedback and to model a sample policy scenario in order to illustrate current capabilities.

Development of a Carbon-Fiber Composite Repair System for Offshore Risers

Scipedia content — Wed, 03 Feb 2021 19:10:46 +0100

Composite systems are a generally-accepted method for repairing corroded and mechanically-damaged onshore pipelines. The pipeline industry has arrived at this point after more than 15 years of research and investigation. Because the primary method of loading for onshore pipelines is in the circumferential direction due to internal pressure, most composite systems have been designed and developed to provide hoop strength reinforcement. On the other hand, offshore pipes (especially risers), unlike onshore pipelines, can experience significant tension and bending loads. As a result, there is a need to evaluate the current state of the art in terms of assessing the use of composite materials in repairing offshore pipelines and risers. The significance of the body of work presented herein is that this study is the first comprehensive evaluation of a composite repair system designed for the repair of offshore risers using a strain-based design method coupled with full-scale prototype testing. This paper presents findings conducted as part of a joint industry effort involving the Minerals Management Service, the Offshore Technology Research Center at Texas A&M University, Stress Engineering Services, Inc., and several composite repair manufacturers to assess the state of the art using finite element methods and full-scale testing methods. Representative loads for offshore risers were used in the test program that integrated internal pressure, tension, and bending loads. This program is the first of its kind and likely to contribute significantly to the future of offshore riser repairs. The end result of this study was the development of a carbon-fiber repair system that can be easily deployed to provide significant reinforcement for repairing risers. It is anticipated that the findings of this program will foster future investigations involving operators by integrating their insights regarding the need for composite repair based on emerging technology.Copyright © 2008 by ASME

Air quality management in Auckland, New Zealand

Scipedia content — Wed, 03 Feb 2021 19:05:22 +0100

quality in New Zealand is perceived by many to be very good. This is facilitated by low population density, geographical isolation and a maritime climate. The climate and weather of New Zealand is also affected by large scale wind systems which promote westerly winds and aid dispersion. Despite favourable conditions, air pollution is a problem in many urban centres in New Zealand. Although industrial emissions contribute to pollution, emissions from domestic and traffic sources are significant. Outdoor burning and domestic fires are common, and are a major source of air pollutants and complaints. National Environmental Standards for Ambient Air Quality were introduced in 2004 but these are unlikely to be achieved in a number of locations including Auckland, New Zealand’s largest city, where traffic emissions are the major source of air pollution. Auckland’s population is 1.3 million people (almost one third of the national total). The city covers an area approximately equal in size to London. Poorly developed public transport services and urban sprawl have resulted in reliance on private vehicles, and ownership rates in New Zealand are among the highest in the world. In conjunction with an aged vehicle fleet and severe traffic congestion, the resulting air pollution has become a significant issue in Auckland. This paper considers the process of air quality management in New Zealand, illustrated by the particular problems systemic to Auckland. Policy responses include a Regional Land Transport Strategy with health protection as a key objective. However, it is far from certain whether these will successfully deliver cleaner air, and further national guidance and additional transport focussed regulations may be needed to achieve the air quality improvements in Auckland necessary to meet the national Standards.

A low power VLIW processor generation method by means of extracting non-redundant activation conditions

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

This paper proposes a low power VLIW processor generation method by automatically extracting non-redundant activation conditions of pipeline registers for clock gating. It is important for the best power reduction by clock gating to create control signals that can completely shut off redundant clock supplies for registers. In order to generate the control signals automatically, the proposed method utilizes high-level architecture information called Micro-Operation Descriptions, which describes a VLIW processor architecture. Exploiting the Micro-Operation Descriptions in a VLIW processor generation process, the proposed method automatically extracts the non-redundant activation conditions that can control clock gating to supply the minimum clocks to the pipeline registers. Using the non-redundant activation condition extraction, the proposed method achieves short calculation time and low area overhead; the proposed method can be applied to VLIW processor generation. Experimental results show that the VLIW processor generated with proposed method achieves power reduction about 60% compared to the non-clock-gated VLIW processor, and about 35% compared to the VLIW processor that is applied clock gating by PowerCompiler with negligible area overhead.

Design of a Research Platform for En Route Conflict Detection and Resolution

Scipedia content — Wed, 03 Feb 2021 18:49:53 +0100

This paper describes the process of designing a software tool for testing en route air traffic management decision support tool functionalities in a research environment. This effort focused on the development of a scalable, low maintenance software application to replace a legacy en route conflict prediction tool. Previous development efforts provided the lessons learned that guided the development of the new en route conflict prediction tool. This new tool met near term functional requirements while allowing flexibility to support future research objectives both inside and outside of the en route domain. The software process encouraged incremental prototyping and short development intervals. The development team used best practices to increase the reliability and maintainability of the software. The tool was also ported to multiple hardware and operating system platforms to further increase its scalability. When compared to the legacy en route conflict prediction tool, the new application had seven times fewer highly complex functions, while maintaining data integrity to ensure consistent predictions.

Analysis of Handoffs for Future En Route Automation

Scipedia content — Wed, 03 Feb 2021 18:46:58 +0100

The Federal Aviation Administration (FAA) is developing the En Route Automation Modernization (ERAM) system to replace the current air traffic controller automation. In order to support the developmental and operational testing of ERAM, a study was conducted by the Automation Metrics Test Working Group (AMTWG) with the objective to address questions related to the handoff of flights by air traffic controllers as the flights pass from one controlling sector to another. Specifically, how effective would an automatic initialization of handoff (auto-init) be? Furthermore, what are the best situations for an accurate automatic initialization? In order to address these questions, handoffs needed to be investigated to determine the different possible scenarios and then analyzed to determine the efficiency of an automatic initialization within each scenario. Prior to the implementation of any testing strategy, actual flight data was collected for analysis. The data was analyzed for different events to determine the frequency of occurrence, and accuracy was determined based on statistics within each event crossing. The same strategy will be applied to actual ERAM data when it becomes available. The main metric selected for this study was the comparison of the predicted sector to actual next sector of handoff.

Artificial Neural Networks Ensemble Used for Pipeline Leak Detection Systems

Scipedia content — Wed, 03 Feb 2021 18:46:34 +0100

The physical and operational properties of pipelines vary greatly. There is thus no universally applicable method, external or internal, which possesses all the features and the functionality required for a perfect leak detection performance. The authors of this paper know quite well that traditional methods, in a low uncertainty environment, overcome artificial intelligence methods of leak detection systems. If one considers the real world as a creator of uncertainties, neural networks and fuzzy systems emerge as important promising technologies for the development of leak detection systems. In this work, we propose a method for constructing ensembles of ANNs for pipeline leak detection. The results obtained in our experiments were satisfactory.Copyright © 2008 by ASME

Making IP traffic engineering robust to intra- and inter-AS transient link failures

Scipedia content — Wed, 03 Feb 2021 18:35:47 +0100

Intra- and inter-AS transient link failures are common in operational IP networks. Robust intra- and inter-AS traffic engineering (TE) schemes have been proposed to optimize network performance against transient link failures. The existing literature has focused solely on either intra- or inter-AS link failure. They have, however, neglected the interactions between robust intra- and inter-AS TE, specifically the impact of intra-AS link failure on inter-AS TE and vice versa. As a result, the overall network performance may not be truly robust to link failures if the interactions are neglected. This paper proposes a joint robust TE approach that takes the interactions into account for achieving good network performance under both normal state and any single intra- or inter-AS link failure. We propose a two-phase heuristic to solve the problem and compare its performance with four alternative approaches that do not consider the interactions. Evaluation results reveal that our joint robust TE approach achieves higher robustness against intra- and inter-AS link failures than all the alternatives.

NEWSKY Networking the Sky for Aeronautical Communications

Scipedia content — Wed, 03 Feb 2021 18:29:02 +0100

n overview of the NEWSKY project (“NEtWorking the SKY”) is given. This project is co-funded by the European Commission within the 6th Framework Programme and has started in February 2007. The main goal of the NEWSKY project is to show that the integration of different communications systems and different applications into a global, heterogeneous network for aeronautical communications is feasible and how this integration can be achieved. The envisaged applications comprise not only Air Traffic Control (ATC) and Air Traffic Management (ATM) but also airline and passenger communications (AOC, AAC, APC). The aim of NEWSKY is not the development of new link technologies; rather, NEWSKY aims to develop an innovative networking concept to integrate different existing and emerging link technologies into a single, global network for a secure, seamless and robustly redundant communication system, which is scalable to cope with future long-term increasing demands. High benefits are expected from the increased information availability and information sharing possibilities that the NEWSKY network will enable.

New Brushless Synchronous Machine for Vehicle Application

Scipedia content — Wed, 03 Feb 2021 18:23:57 +0100

The results of theoretical and experimental investigations of the special synchronous machine and the electrical drive on its base are submitted. This paper covers the principle of operation the brushless synchronous machine, its experimental characteristics, comparison with other types of motors, technique of account of the electromagnetic torque, functional circuits of the electric drive with the independent excited synchronous reactive motor (FRRM - Field Regulated Reluctance Machine). It is the most favorable application of the considered electric drive in the vehicles with heavy conditions of operation, where such are urgent it advantages, as: brushless, high rigidity of the shaft, large overloads on the torque. It can be used in the regular cars for starter generators, in pure-electrical and hybrid-electrical vehicles for power drive, in independent power generating installations with high-speed of the gas turbine engine and so on. Copyright © 2007 SAE International.

A model for traffic behaviour evaluation based on a discrete event simulation approach

Scipedia content — Wed, 03 Feb 2021 17:59:40 +0100

There are various reasons why both freight and passenger transport demands keep growing significantly not only in Europe, but also worldwide. In this framework, the interaction between such demands in urban areas assumes a relevant role in the overall performances of an urban transportation system. In this paper, the special case of a seaport located in an urban area is considered, since such a situation often occurs in cities grown along the coast around an “old” port. Then, to cope with the problem of simply modeling the freight and passenger flows in urban areas, in this paper a colored Petri net modeling approach is proposed.

Study on Mechanical Property of Corroded Pipeline

Scipedia content — Wed, 03 Feb 2021 17:58:44 +0100

Stochastic finite element method (FEM) was applied to analyze the mechanical property of the corroded pipeline. Firstly, mechanical properties of the corroded steel were studied. Then, dynamic properties of the corroded pipeline were investigated; sensitivity analyses were performed on the effective factors respectively. Considering the distribution characters of the defects on the pipe surface as stochastic variables, a series of numerical investigations were executed on the corroded pipeline. Relation between the dynamic property of the submarine pipeline and the corrosion state of the material is achieved.

Alarm Management for Pipelines

Scipedia content — Wed, 03 Feb 2021 17:58:18 +0100

In 2005 the National Transportation Safety Board, concluded that an effective alarm review/audit system will increase the likelihood of controllers appropriately responding to alarms associated with pipeline leaks. This paper looks at the pipeline industry in the broader context of process industry alarm management and how the best practices of the process industry apply to the pipeline industry.Copyright © 2008 by Matrikon Inc.

Air Traffic Complexity: An Input-Output Approach

Scipedia content — Wed, 03 Feb 2021 17:52:57 +0100

There has been much effort to increase airspace capacity and one of the fundamental research problems is to measure the traffic complexity inside sectors. This paper proposes a new method for describing the air traffic complexity of a given traffic situation. We view the airspace as a closed- loop input-output system and define air traffic complexity as "how difficult" a given traffic situation is, in terms of the control activity required to resolve it, in response to a change in "reference signal", that is the presence of a new aircraft entering the airspace. We present a "complexity map" that offers a graphical view of the complexity for a given traffic situation. We also discuss how to extract a scalar measure of air traffic complexity from the complexity map. We illustrate our methodology with a few examples.

Evaluating UAS Autonomy Operations Software in Simulation

Scipedia content — Wed, 03 Feb 2021 17:47:27 +0100

We describe a software simulation test bed for evaluating Concepts of Operation (CONOPS) for Unmanned Aircraft Systems (UAS) flying earth science missions. The Mission Operational Concept Evaluation Framework (MOCEF) aids in the rapid evaluation of proposed system automation designs, including intelligent controllers for vehicles, sensor payloads, and decision support systems, on a wide range of missions. Such broad evaluation is prohibitively expensive when limited to physical experiments and real missions. MOCEF allows evaluation of automation concepts in multiple mission scenarios operating in a wide range of environments. It records mission metric parameters such as the quality of sensor data obtained, flight time, stress on the vehicles, and air traffic control rules infringed or invoked. This information can be fed into specific mission metric formulas to rate performance and into the Google Earth tool for visualization.

SCADA “Supervisory Control And Data Acquisition” implementation in “Sui Northern Gas Pipelines Limited Pakistan” (SNGPL)

Scipedia content — Wed, 03 Feb 2021 17:47:01 +0100

This paper will explain SCADA “Supervisory Control And Data Acquisition”, and the need for quality management information systems in today’s competitive and widely spread business world. Information systems help companies extend their reach to faraway locations, reshape jobs and work flows, and perhaps profoundly change the way they conduct their business. SNGPL is the only gas transportation company in Pakistan, which is utilizing the SCADA system on such a large scale, with much effect. The SCADA system, implemented in SNGPL since 2000, has greatly changed the corporate profile and organizational procedures as well as the public image of the company. DMC phones and traditional tele-printer messages were mainly used for the communication/dissipation of information across the organization before the implementation of SCADA. No timely or abrupt response could have been given to any sabotage/rupture of pipelines, mainly due to lack of an effective and efficient information system throughout the organization. Nowadays, while monitoring mainline pressure and flow at Gas Control Center Faisalabad, the desk operator would immediately issue a command to close the nearest valve, not only to save the gas volume being purged into the atmosphere but also to ensure the safety of precious human lives and public property. Moreover, the company’s image in the consumer market has improved greatly due to an uninterrupted gas supply to all major cities and towns of Punjab and NWFP. In short, SCADA has proved to be a blessing in disguise for SNGPL, keeping in view its widely spread infrastructure.

Modeling Tactical Trajectory Accuracy Effects on Traffic Flow Management Operations

Scipedia content — Wed, 03 Feb 2021 17:38:07 +0100

Software, databases, and methods from previous predictive model studies were used to assess benefits of augmenting parametric methods with kinetic model trajectory predictions. Those results were consistent with other studies of models for aircraft position prediction accuracy during climbs and descents. A kinetic model reduced error for average arrival meter fix crossing time predictions across a one-hour predictive range by 0.6 minutes (39% improvement) when compared to the parametric model used in an experimental traffic flow management system. These results are comparable to the kinetic model's 1.1 minute (47% improvement) error reduction over the operational traffic flow management's parametric implementation. Data also show national convective weather conditions do not appear to affect performance differentials. Kinetic systems do not necessarily ensure performance superior to parametric systems in all areas. Parametric models of air traffic management procedural effects on altitude profiles demonstrated an average 10% error reduction for selected sector entry and occupancy metrics. The sources of these particular errors are not inherent to kinetic methods and could be addressed by procedural modeling improvements. The errors reductions achievable by kinetic models do not ameliorate pre-departure uncertainties, though traffic flow management functions a variety of air traffic management teams and functions may benefit from these levels of increased accuracy at their information exchange boundaries, particularly at Center, sector, and meter-fix crossings.

Reducing greenhouse emissions by improving traffic signal operations

Scipedia content — Wed, 03 Feb 2021 17:28:30 +0100

Refereed/Peer-reviewed

Experimental Evaluation of an Integrated Datalink and Automation-Based Strategic Trajectory Concept

Scipedia content — Wed, 03 Feb 2021 17:04:50 +0100

This paper presents research on the interoperability of trajectory -based automation conce pts and technologies with modern Flight Management Systems and datalink communication available on many of today’s commercial aircraft. A tight integration of trajectory -based ground automation systems with the aircraft Flight Management System through da talink will enable mid -term and far -term benefits from trajectory -based automation methods. A two -way datalink connection between the trajectory -based automation resident in the Center/TRACON Automation System and the Future Air Navigation System -1 integra ted FMS/datalink in NASA Ames’ B747 -400 Level D simulator has been established and extensive simulation of the use of datalink messages to generate strategic trajectories completed. A strategic trajectory is defined as an aircraft deviation needed to solv e a conflict or honor a route request and then merge the aircraft back to its nominal preferred trajectory using a single continuous trajectory clearance. E ngineers on the “ground side” of the datalink generated lateral and vertical trajectory clearances and transmitted them to the Flight Management System of the 747 ; th e airborne automation then fl ew the new trajectory without human intervention , requiring the flight crew only to review and to accept the trajectory . This simulation established the protoco ls needed for a significant majority of the trajectory change types required to solve a traffic conflict or deviate around weather. This demonstration provides a basis for understanding the requirements for integration of trajectory -based automation with c urrent Flight Management Systems and datalink to support future National Airspace System operations.

MET: an efficient static routing algorithm for WDM networks with full wavelength conversion

Scipedia content — Wed, 03 Feb 2021 17:01:19 +0100

ming at simultaneously minimizing the network wavelength requirement (NWR) and the network bandwidth requirement (NBR) for a given traffic matrix, we focus on the static routing problem in WDM networks with full wavelength conversion. A new algorithm MET (most even traffic distribution) is proposed. MET consists of two steps, the initial shortest-path-based route assignment, followed by a rerouting process to refine the solution. Unlike existing approaches, MET makes each rerouting decision by judiciously balancing the overall network traffic loads. A uniformity function is defined and embodied in MET to characterize the traffic load distribution in the network. Numerical results show that MET outperforms the best existing algorithm (Min-hops) by requiring less amount (about 10% saving) of network bandwidth (NBR) and less number of wavelengths (NWR).

Investigation of slug flow characteristics in inclined pipelines

Scipedia content — Wed, 03 Feb 2021 16:54:24 +0100

In the present work a numerical analysis of the slug flow in inclined pipelines is performed with an aim to improve the understanding of slug flow characteristics over hilly-terrain section. The solution is obtained with the two-fluid model on its one-dimensional form. It consists of two sets of conservation equations of mass and linear momentum for the liquid and gas phases. The slug capturing methodology involves the numerical solution of the equations using a finite volume formulation, which is capable of naturally predicting the onset of slugging from a stratified flow regime, as well as the growth and collapse of the slugs. Flows of an oil–gas mixture in slightly inclined pipe configurations are investigated. Three types of pipelines were considered: horizontal, descending and a V-section pipeline. The influence of the gravity effect in average slug parameters, such as frequency, velocity and length is addressed. Qualitative comparisons with experimental observations in the literature show that the methodology seems to be able to correctly predict the effect of pipe inclination on the occurrence (or not) of the slug regime, as well as different overall slugging behaviour in V-section pipes if different inlet gas and liquid superficial velocities are imposed.

Automated Conflict Resolution: A Simulation Evaluation Under High Demand Including Merging Arrivals

Scipedia content — Wed, 03 Feb 2021 16:44:01 +0100

Performance of a n automated conflict resolution algorithm is assessed. Evaluations are based on fast -time simulation s of 24 hours of nominal and heavily increased air traffic demand in the Cleveland Air Route T raffic C ontrol Center airspace. Departure, en -route, and arrival traffic were represented, based on recorded Host data . The algorithm is designed to resolve detected conflicts —projected to be between two and twenty minutes from first loss of separation —by amending the lateral, vertical, or longitudinal trajectory of one aircraft such that the conflict is resolved, no new conflicts are created, and the aircraft is returned to its original flight plan . The results indicate that the conflict resolution algorithm is ca pable of resolving conflicts safely and efficiently at traffic levels significantly higher than today under nominal conditions . Safety and efficiency metrics are offered as benchmarks for comparison with alternative algorithms.

Towards Selective Addressing of Aircraft with Voice Radio Watermarks

Scipedia content — Wed, 03 Feb 2021 16:39:26 +0100

The current voice communication system in use worldwide for Air Traffic Control (ATC) was standardised more than sixty years ago. Digital watermark technology for intellectual property right protection is part of many digital medias like music, pictures and videos. The EUROCONTROL Experimental Centre (EEC) proposed employing this mass-market technique to embed a digital signature as watermark in ATC voice communication. The project is called Aircraft Identification Tag (AIT). Watermarked speech allows the automatic identification of the originator of the received voice message in real-time. This AIT concept helps to increase the safety in ATC and secures the legacy voice communication system against malicious attacks. Embedding the destination address of the called aircraft into the controller’s speech would extend AIT’s safety benefit towards the aircraft by an automatically generated attention getter in the cockpit when the aircraft is called. For this, active controller cooperation is required. This paper proposes the replacement of the currently used ‘Push To Talk’ (PTT) switch by the concept of a selective PTT switch, with which the controller indicates the addressed aircraft. An early demonstrator of the selective PTT switch concept was presented to former controllers for a preliminary scenario-based evaluation of the usability. The results are positive.

A computer simulation scenario analysis approach as a decision support tool for transportation systems planning

Scipedia content — Wed, 03 Feb 2021 16:17:36 +0100

This paper describes how, as the level of traffic congestion rises and the complexity of traffic networks increase, the development of effective transportation strategies becomes the most challenging task for every transport authority. Meanwhile, advancements in computer technology, especially the technique of computer simulation offer a new effective way for testing plausible solutions prior to implementation. Based on a microscopic traffic simulation model this paper presents an evaluation of the effectiveness of alternative traffic solution interventions on a main arterial highway in Nicosia, Cyprus. In particular, computer experiments are carried out to test various plausible scenario solutions. The scenarios under evaluation, involve the use of dedicated bus lanes, high occupancy vehicle lanes and road enhancement interventions. The simulation results show that an attractive scenario such as the use of dedicated bus lanes, if not designed properly, could bring disastrous results not only to the private car transport mode but also to the bus transport mode as coupling effects cause buses to get stuck with the rest of the traffic. By going through a computer experimentation process and scenario analysis a viable solution is derived, where restricted lanes for buses and high occupancy vehicles are introduced in combination with road geometry redesign and traffic re-direction at key points.

Numerical Computation of Compressible Laminar Flow With Heat Transfer in the Entrance Region of a Pipe

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

The authors’ research work on pressure drop along gas transmission pipelines raised questions regarding the development length of the corresponding compressible flow and the effect of heat transfer in the entrance region on the pressure drop along the whole length of the pipe. In this paper, laminar, viscous, compressible flow in the entrance region of a pipe is investigated numerically in two dimensions. The numerical procedure is a finite-volume based finite-element method applied on unstructured grids. This combination together with a new method applied for boundary conditions allows accurate computation of the variables in the entrance region. The method is applied to some incompressible cases in order to verify the results. The results are confirmed by previous numerical and experimental research on the developing length in incompressible flow.Copyright © 2008 by ASME

Optimization model for medium term natural gas commitment

Scipedia content — Wed, 03 Feb 2021 16:13:18 +0100

In this paper we study the optimal natural gas commitment for a known demand scenario. This study implies the best location of GSUs to supply all demands and the optimal allocation from sources to gas loads, through an appropriate transportation mode, in order to minimize total system costs. Our emphasis is on the formulation and use of a suitable optimization model, reflecting real-world operations and the constraints of natural gas systems. The mathematical model is based on a Lagrangean heuristic, using the Lagrangean relaxation, an efficient approach to solve the problem. Computational results are presented for Iberian and American natural gas systems, geographically organized in 65 and 88 load nodes, respectively. The location model results, supported by the computational application GasView, show the optimal location and allocation solution, system total costs and suggest a suitable gas transportation mode, presented in both numerical and graphic supports.

Accurate Positioning for Vehicular Safety Applications - The SAFESPOT Approach

Scipedia content — Wed, 03 Feb 2021 15:54:44 +0100

One of the main restrictions of present-day driver assistance systems is the limited temporal and spatial horizon. In order to overcome this limitation, the European integrated project SAFESPOT aims to develop a safety margin assistant, which provides the driver with appropriate recommendations for how to avoid critical situations. For reaching that goal, positioning algorithms with sub-meter accuracy are necessary. In this paper, the SAFESPOT approach for accurate relative positioning of vehicles is presented. The main idea is to combine several sources of information from a cooperative vehicle ad-hoc network using a data fusion module. Thus, the single positioning technologies (e. g. satellite navigation, communication signals, and landmarks) as well as the data fusion algorithms are explained. The results are expected to improve localization accuracy in a way which makes it possible for vehicular safety applications to determine even the lane in which a vehicle is travelling.

Linguistic knowledge sources for spoken language understanding

Scipedia content — Wed, 03 Feb 2021 15:47:44 +0100

The objective of the Unisys Spoken Language Systems effort is to develop and demonstrate technology for the understanding of goal-directed spontaneous speech. The Unisys spoken language architecture couples speech recognition systems with the Unisys discourse understanding system, PUNDIT. PUNDIT is a broad-coverage language understanding system used in a variety of message understanding applications and has been extended to handle spoken input. Its power comes from the integration of syntax, semantics, and pragmatics processing, the ability to port rapidly to new task domains, and from an open, modular architecture. PUNDIT is unique in its ability to handle connected discourse; it includes a reference resolution module that tracks discourse entities and distinguishes references to previously mentioned entities from the introduction of new entities. The PUNDIT front-end supports turn-taking dialogue and permits the system to include both questions and answers in building an integrated discourse context, required for the handling of interactive communication. PUNDIT has been interfaced to several speech recognition systems (MIT SUMMIT and ITT VRS-1280) to perform applications in direction-finding assistance, air travel planning and air traffic control.

Anticipatory vehicle routing using delegate multi-agent systems

Scipedia content — Wed, 03 Feb 2021 15:40:08 +0100

This paper presents an agent-based approach, called delegate multi-agent systems, for anticipatory vehicle routing to avoid trafﬁc congestion. In this approach, individual vehicles are represented by agents, which themselves issue light-weight agents that explore alternative routes in the environment on behalf of the vehicles. Based on the evaluation of the alternatives, the vehicles then issue light-weight agents for allocating road segments, spreading the vehicles’ intentions and coordinating their behavior. To evaluate the approach, we have developed an initial prototype application. Test results indicate that delegate multi-agent systems are a promising approach for anticipatory vehicle routing. ispartof: pages:87-93 ispartof: Intelligent Transportation Systems Conference, 2007. ITSC 2007. IEEE pages:87-93 ispartof: ITSC location:Seattle, USA date:30 Sep - 3 Oct 2007 status: published

Traffic Management and Traffic Engineering for the Future Internet

Scipedia content — Wed, 03 Feb 2021 15:37:52 +0100

International audience; The crucial future role of Internet in society makes of network monitoring a critical issue for network operators in future network scenarios. The Future Internet will have to cope with new and different anomalies, motivating the development of accurate detection algorithms. This paper presents a novel approach to detect unexpected and large traffic variations in data networks. We introduce an optimal volume anomaly detection algorithm in which the anomaly-free traffic is treated as a nuisance parameter. The algorithm relies on an original parsimonious model for traffic demands which allows detecting anomalies from link traffic measurements, reducing the overhead of data collection. The performance of the method is compared to that obtained with the Principal Components Analysis (PCA) approach. We choose this method as benchmark given its relevance in the anomaly detection literature. Our proposal is validated using data from an operational network, showing how the method outperforms the PCA approach.

Active Heads-up Display based Speed Compliance Aid for Driver Assistance: A Novel Interface and Comparative Experimental Studies

Scipedia content — Wed, 03 Feb 2021 15:35:55 +0100

In this paper we introduce a novel laser-based wide-area head-up windshield display, and its evaluation for assisting a driver to comply with speed limits. The paper includes a comparative experimental evaluation with an instrumented vehicle of four different types of display protocols. The result is the dynamic active display - speed control system, a part of the dynamic active display concept of presenting safety-critical visual icons to the driver in a manner that minimizes deviation of his or her gaze direction without adding to unnecessary visual clutter. The experimental system make use of global positioning system (GPS) information to locate the vehicle on an annotated map with speed limits, the novel heads-up-display, and 3 biologically inspired alerts to present speed and speed limit information on this display. Each alert strategy is tested on actual roadways, and compared with the situation of having to rely only on the dash indicators. Given the inclination, drivers who are given an over-speed warning alert reduced the amount of "time-to-slow-back-down" to speed limit by 42% as compared to drivers not given the alert. The use of other alerts produced similar decreases. Ultimately, each of these alerts exhibit strengths in complementing ways, indicating that a combination of these alerts would provide the best strategy for promoting speed limit compliance.

Inspection & Assessment of Damaged Subsea Pipelines: A Case Study

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

The Central Area Transmission System (CATS) in the UK sector of the North Sea delivers natural gas through a 404 km pipeline from the CATS riser platform to the North East coast of England. During the summer of 2007 this 36 inch diameter natural gas pipeline was damaged by a vessel anchor. The anchor lifted the pipeline from under the seabed, dragged it across the seabed, bending the pipe and locally deforming it. This event resulted in a significant inspection, assessment and repair programme before the pipeline could safely return to operation. This paper describes the detailed structural assessment of the damaged pipeline and the inspection and repair operations. Following inspection of the pipeline by divers, the damage was assessed using the “Pipeline Defect Assessment Manual” (PDAM). The manual was prepared from research primarily for onshore pipelines: this paper discusses the strengths and weaknesses of PDAM and key differences in defect assessment for onshore and offshore pipelines. The paper highlights several very important lessons learnt from this incident, including: • the complex stresses developed in a pipeline that is pulled and moved by an anchor; • the need for damage assessment methods for pipe containing high compressive stresses and ‘locked-in’ stresses; • the safety aspects and complexity of inspecting a pressurised and damaged subsea pipeline. These lessons learnt are then translated into recommendations for the industry, and advice to other subsea pipeline operators.Copyright © 2008 by ASME

Scanning Vibrating Electrode Technique as an application for measuring corrosion activity of carbon steel welded pipelines

Scipedia content — Tue, 02 Feb 2021 08:33:16 +0100

The scanning vibrating electrode technique, also known as SVET, is a relatively new technique which offers the opportunity to obtain information concerning corrosion activity on a small scale. However, its utilisation to investigate the corrosion of welds has been limited. SVET experiments were carried out on specimens of different welded sections within two different electrolytes, e.g., 0.35% NaCl solution alone and buffered 0.35% NaCl solution with CO2 saturations. SVET was used during these investigations to evaluate preferential corrosion susceptibilities of weldments.

Multiple Input Support in a Model-Based Interaction Framework

Scipedia content — Tue, 02 Feb 2021 08:30:21 +0100

International audience; Developing for tabletops puts special requirements on interface programming frameworks: managing parallel input, device discovery, device equivalence, and describing combined interactions. We analyse these issues and describe the solutions that were used in IntuiKit, a model- based framework aimed at making the design and development of post-WIMP user interfaces more accessible. Some solutions are simple consequences of the support of multi- modality, while others are more specific to multiple touch. We illustrate these features through examples developed in several tabletop projects, including one application aimed at improving collaboration between air traffic controllers.

A two level optimization approach for long-term planning in a large air transportation network

Scipedia content — Tue, 02 Feb 2021 08:21:03 +0100

International audience; In this communication, the problem of long-term forecasting of the traffic growth in a large air transportation network is considered. This problem is crucial when planning the necessary investments in airports, fleets and air traffic control equipments. The resulting optimization problem is a multilevel one. The proposed approach makes use of two different optimization models: One model is devoted to demand forecasting, while the other defines the air transport supply according to a profit maximization behaviour of the airlines sector. The proposed solution scheme is composed of an iterative process between the current solutions of the demand and the supply optimization problems. Convergence conditions are discussed for this iterative process between these two problems which can be seen as inverse of each other. The proposed optimization approach is briefly illustrated in the case of the long-term forecasting of air traffic in the West Africa region.

Plug-in hybrid electric vehicles in dynamical energy markets

Scipedia content — Tue, 02 Feb 2021 07:45:29 +0100

The plug-in hybrid electric vehicle allows vehicle propulsion from multiple internal power sources. Electric energy from the grid can be utilized by means of the plug-in connection. An on-line energy management (EM) strategy is proposed to minimize the costs for taking energy from each power source. Especially in a dynamical energy market, an on-line optimization algorithm is desirable since energy prices change over time. By construction, the proposed EM system can operate with, and without prediction information. If predictions are available, an electronic horizon is applied to anticipate on up-coming events and further optimize the strategy. Illustrative examples are given to explain the added value for both solutions. Also the situation where energy is transferred back to the grid is considered. © 2008 IEEE.

Rotating optical geometry sensor for fresh water pipe inspection

Scipedia content — Tue, 02 Feb 2021 07:32:54 +0100

The inspection of sewer or fresh water pipes is usually carried out by a remotely controlled inspection vehicle equipped with a high resolution camera and a lightning system. Beside the subjective classification of pipe defects trough the operator standard CCTV technology is not suitable for detecting geometrical deformations resulting from e.g. structural mechanical weakness of the pipe, corrosion of the cast-iron material or sedimentations. The Fraunhofer Institute for Information and Data Processing in Karlsruhe, Germany developed a new Rotating Optical Geometry Sensor (ROGS) for fresh water pipe inspection which is capable of measuring the inner pipe geometry very precisely over the whole pipe length. The developed sensor concept has been applied successfully to fresh water and sewer pipes - the results will be presented in detail.

Using Surface Demand Trends to Evaluate Multiple Airport Surface Initiatives

Scipedia content — Tue, 02 Feb 2021 07:30:04 +0100

One of the major difficulties in performing post-implementation analysis for an initiative is the lack of control over the environment. Many times, multiple initiatives are being attempted simultaneously and it is difficult to attribute operational impacts to specific programs. In this paper, we examine the taxi time and departure rate impacts of two recent enhancements at Orlando International Airport (MCO): a new runway and enhanced Air Traffic Control surface surveillance through the Airport Surface Detection Equipment – Model X (ASDE-X). Both enhancements have had positive effects on surface efficiency; however, each initiative exhibits unique impact characteristics when examined in relation to the surface demand. More specifically, plots of taxi-out time and departure rate vs. surface demand show quite different behaviors. We interpret the results and believe similar analysis should be useful for refining the estimated benefits of other ASDE-X sites and predicting the impact of future surface initiatives. The suggested methodology of examining the different trend characteristics of a metric in relation to demand should provide a valuable method for future post-implementation analysis.