Scipedia: Documents published in 2011

The urban logistic service model in the aspect of the domestic logistic system

Scipedia content — Wed, 03 Feb 2021 22:01:09 +0100

The paper presents the research effects of the development project entitled “The Model of the Logistic System for Poland as a Way to Transport Comodality in the EU” in relation to the logistic service of a town. Urban agglomeration service models that employ Load Consolidation Centers and Urban Transhipment Hubs are also presented in the paper. The issues of urban logistics in the aspect of the delivery of goods to customers located within the city borders are presented as an optimization task with the service cost minimization criterion. Proposals for practical applications of the approach are exemplified with a model developed for the Warsaw agglomeration.

Distributed E2E QoS-Based Path Computation Algorithm over Multiple Inter-domain Routes

Scipedia content — Wed, 03 Feb 2021 21:50:41 +0100

International audience; Internet usages have changed with the emergence of value added services relying on a higher interactivity and needs for a better quality of experience (QoE). Telecommunication operators have to face a continuing growth of new types of Internet traffic (video, games, telepresence, etc.) imposing not only a more efficient utilization of their network infrastructure resources, but also the generation of new revenues to pursue investments and sustain the increasing demand. Such services generally cross multiple domains, but inter-domain routing protocols still have some limitations in terms of service assurance. For example, BGP's single route announce for a destination limits potential traffic engineering features (e.g. no quality of service price/efficiency optimization, inter-domain shared route protection , inter-domain load balancing, etc.). In order to provision end-to-end inter-domain connections that obey to constraints such as bandwidth, delay, jitter, and packet loss for these services, an interesting approach is to compute end-to-end (e2e) paths over multiple inter-domain routes. This will allow establishing more efficiently the inter-domain connections with respect to requested QoS constraints and sharing these constraints (and associated revenues) among multiple operators to globally accept more demands in the system, while keep satisfying the customer QoE. To address these challenges, we propose an efficient distributed inter-domain algorithm that computes such constrained paths among a set of domains, exploring multiple inter-domain routes. We demonstrate that our algorithm not only increases success rate in delivering feasible paths, but also admits more connections and keeps a reasonable runtime.

Productivity Improvement in Construction of Onshore Oil & Gas Pipeline Tie in Joints Execution

Scipedia content — Wed, 03 Feb 2021 21:41:16 +0100

One of the economical ways of transporting crude oil or gas over long distances is through onshore pipelines. Construction of onshore pipelines, involves considerable repetitive activities at various stages of the project. Cost incurred in the construction of pipelines depends on the length of the pipeline, the route and the timely completion of the project. One of the difficult areas in the execution of onshore pipeline construction is “tie in” joints on either side of crossings like roads, rail tracks etc. The aim of this research work is to improve the productivity of execution of “tie in” joints in onshore oil transporting pipelines so that more number of “tie-in” joints can be executed in a day. Improvements are proposed by suggesting alternatives like advanced tools and equipments or by suggesting alternative work methods to the existing conditions. Suggestion of alternative tools is achieved by using end caps to cover the ends of the pipeline sections, ring type cutting and beveling machines and semi automatic welding for “tie-in” joints. Also, an alternative work sequence has been suggested that has the potential to reduce the operational cost of equipments to a certain extent. The outcome after incorporating these alternatives to the existing as well as the proposed alternative work method is assessed by developing a simulation model. Comparison based on percentage reduction between the alternative work method and the existing work method revealed a 50% reduction in time and 46% reduction in cost.

Network planning and traffic engineering in ecoframe optical packet ring

Scipedia content — Wed, 03 Feb 2021 21:38:26 +0100

International audience; ECOFRAME ring is a novel network technology for the metropolitan transport that exploits optical packet switching and optical transparency. Each station in this ring is equipped with a tunable transmitter and a number of fixed receivers, able to extract traffic from a predefined set of wavelengths (number of wvl. ≥ 1). Receivers can be shared by different destinations, of- fering to this technology an ability to achieve significant CAPEX savings by using the optimum number of network resources, if properly dimensioned. In this paper we present a wide set of conclusions obtained when applying different network planning and traffic engineering tools in investigating an optimal design and evaluating performances of an ECOFRAME ring. More precisely, regarding network planning issues, we have estimated equipment costs, identified different network configurations and studied their impact on ring performances. Finally, we have found the potential savings when ring is properly designed. On the other hand, based on the previous results, we have identified the optimal ring configuration from price, capacity and scheduling point of view, suggested a cheap and fair scheduling policy for a general case and evaluated the positive impact of statistical multiplexing due to the WDM dimension, on the ring capacity. We have shown that an OPS ring that is properly dimensioned can achieve a solid QoS performance without slot reservation mechanisms.

Drowsiness detection by thoracic effort signal analysis in real driving environments

Scipedia content — Wed, 03 Feb 2021 21:31:33 +0100

Detection of drowsiness while driving is a leading objective in advanced driver assistance systems. This work presents a new index to assess the alertness state of drivers based on the respiratory dynamics derived from an inductive band. More than 100 hours of driving in real environments from 13 healthy subjects were analyzed. The proposed method has a sensitivity of 93.7% and specificity of 86.3% in detecting full awake drivers while it has a sensitivity of 83.1% and specificity of 95.3% in detecting drowsy drivers. The results show that the proposed index may be promising to assess the alertness state of real drivers.

Peer Reviewed

Best-effort Highway Traffic Congestion Control via Variable Speed Limits

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

International audience; The problem of controlling the congestion front in a single link road section is considered in this paper. For this purpose, we introduce a new variable-length two-cell lumped model composed of; one congested cell, and another in free flow. This model has the advantage of having few states while preserving the vehicle conservation property. This model is used as a basis to design a simple "best-effort" controller that regulates (at its best) the congestion front to some prespecified value. The control law can be implemented using only information about the congestion front position.

Anticipatory wireless bitrate control for blocks

Scipedia content — Wed, 03 Feb 2021 21:13:48 +0100

We present BlockRate, a wireless bitrate adaptation algorithm designed for blocks, or large contiguous units of transmitted data, as opposed to small packets. Our work is motivated by the observation that recent research results suggest significant overhead amortization benefits of blocks. Yet state-of-the-art bitrate algorithms are optimized for adaptation on a per-packet basis, so they can either have the amortization benefits of blocks or high responsiveness to underlying channel conditions of packets, but not both. To bridge this disparity, BlockRate employs multiple bitrates within a block that are predictive of future channel conditions. In each feedback round, BlockRate uses a history-based scheme to predict the SNR for packets within the next block. In slow-changing scenarios as under pedestrian mobility, BlockRate uses a simple linear regression model to predict the SNR trend over the next block. In fast-changing scenarios as under vehicular mobility, BlockRate uses a path loss model to capture more significant SNR variations within a block. We have implemented a prototype of BlockRate in a commodity 802.11 driver and evaluated it via deployment on an indoor mesh testbed as well as an outdoor vehicular testbed. Our evaluation shows that BlockRate achieves up to 1.4× and 2.8× improvement in goodput under indoor and outdoor mobility respectively.

Verification of PCCP Failure Margin and Risk Curves

Scipedia content — Wed, 03 Feb 2021 21:12:05 +0100

Failure margin analysis of prestressed concrete cylinder pipe (PCCP) evaluates the effect of broken prestressing wires on performance of the pipe and its margin to failure using the risk curves technology. The risk curves technology is based on structural analysis calibrated and verified by hydrostatic pressure testing of pipes with broken wires to failure, nonlinear finite element analysis that simulates the behavior of distressed pipe to failure, and external inspection of pipes with broken wires. This paper compares the observed levels of distress from external inspection of failed or highly distressed pipes to those predicted using the risk curves technology with the observed number of broken wires and expected internal pressure.

Pipeline Rehabilitation amidst Environmentally Sensitive Location

Scipedia content — Wed, 03 Feb 2021 21:10:53 +0100

The District of Columbia Water and Sewer Authority (DC Water) was faced with repair of a degrading aerial sewer located in an environmentally sensitive area. The sewer is located over Klingle Creek in US National Park Service land. The sewer is an 18-in sanitary terra cotta line encased in 30-in wide by 30-in deep degrading concrete with support columns and footings position in the steam bed and banks. Significant erosion at the stream bed undermined the stream bed footings. This caused the design span to double and put the aerial sewer in jeopardy. Mitigation options included realignment, replacement, renewal, and footing support updates. The importance of the sewer to accommodate public demand was not well supported by options requiring environmental impact reports or special permits, such as replacement, realignment, and stream bed alterations. Although initial project discussions considered realignment and replacement as viable options, DC Water recognized the urgency for an alternative that did not require extended planning and permitting. The pipe owner contacted Analytical Engineering to provide an FRP (fiber reinforced polymer) repair alternative. Analytical recommend the use of the Tyfo CFRP (carbon fiber reinforced polymer) system for strengthening the exiting encased crossing while eliminating the need for stream bed supports and alterations. The use of the Tyfo CFRP system for external rehabilitation of the crossing also eliminated the need for

Cross-polar aircraft trajectory optimization and the potential climate impact

Scipedia content — Wed, 03 Feb 2021 21:07:39 +0100

Cross-Polar routes offer new opportunities for air travel markets. Transpolar flights reduce travel times, fuel burns, and associated environmental emissions by flying direct paths between many North American and Asian cities. This study evaluates the potential benefits of flying wind-optimal polar routes and assessed their potential impact on climate change. An optimization algorithm is developed for transpolar flights to generate wind-optimal trajectories that minimize climate impact of aircraft, in terms of global warming potentials (relative to warming by one kg of CO 2 ) of several types of emissions, while avoiding regions of airspace that facilitate persistent contrail formation. Estimations of global warming potential are incorporated into the objective function of the optimization algorithm to assess the climate impact of aircraft emissions discharged at a given location and altitude. The regions of airspace with very low ambient temperature and areas favorable to persistent contrail formation are modeled as undesirable regions that aircraft should avoid and are formulated as soft state constraints. The fuel burn and climate impact of cross-polar air traffic flying various types of trajectory including flight plan, great circle, wind-optimal, and contrail-avoidance are computed for 15 origin-destination pairs between major international airports in the U.S. and Asia. Wind-optimal routes reduce average fuel burn of flight plan routes by 4.4% on December 4, 2010 and 8.0% on August 7, 2010, respectively. The tradeoff between persistent contrail formation and additional global warming potential of aircraft emissions is investigated with and without altitude optimization. Without altitude optimization, the reduction in contrail travel times is gradual with increase in total fuel consumption. When altitude is optimized, a one percent increase in additional global warming potential, a climate impact equivalent to that of 4070kg and 4220kg CO 2 emission, reduces 135 and 105 minutes persistent contrail formation per flight during a day with medium and high contrail formation, respectively.

Hydrate formation in natural gas pipelines

Scipedia content — Wed, 03 Feb 2021 20:53:45 +0100

Gas hydrates pose a problem to the flow assurance programs in the oil and gas industry. This paper highlights the mechanisms of hydrate formation in natural gas pipelines. Computational Fluid Dynamics (CFD) was used to gain insight in to the mechanisms of water vapour condensation and consequent water accumulation in the lowered sections of a gas pipeline. The pipeline temperature profile, condensation of water vapour at walls, hydrate formation and hydrate slurry rheology were modelled with user defined functions (UDF) integrated into the CFD-software Fluent. It was found that the uphill sections of gas pipelines are natural sites for water accumulation and hydrate formation. It is demonstrated that CFD is a valuable tool to understand complex physical phenomena occurring in multiphase flow problems.

Low-cost recovery for the code integrity protection in secure embedded processors

Scipedia content — Wed, 03 Feb 2021 20:48:27 +0100

International audience; To ensure the code integrity in secure embedded processors, most previous works focus on detecting attacks without paying their attention to recovery. This paper proposes a novel hardware recovery approach allowing the processor to resume the execution after detecting an attack. The experimental results demonstrate that our scheme introduces a very low impact on the performance while requiring a reasonable hardware overhead.

Managing Gravity Pipelines in Philadelphia

Scipedia content — Wed, 03 Feb 2021 20:41:04 +0100

The Philadelphia (Pennsylvania) Water Department delivers drinking water and operates all storm and sanitary sewers within the city of Philadelphia. This 142-square-mile area contains 3,400 miles of publicly owned sanitary sewers, storm sewers, and a large area of combined sewers. As measurement technology has matured, the department has enhanced its systems for managing its infrastructure. In some areas, these changes have been dramatic. These include use of remote video equipment to inspect city sewers, online monitoring of levels and flows throughout the system, and geographic mapping tools that make it easier to locate specific pipes. Each of these programs requires large databases that require maintenance and application integration. To manage this information, the department has developed a comprehensive set of interfaces available throughout the citywide corporate network that address specific needs and provides for analysis that cuts across several systems.

Novel two-stage algorithm for non-parametric cast shadow recognition

Scipedia content — Wed, 03 Feb 2021 20:40:40 +0100

Environment perception and scene understanding is an important issue for modern driver assistance systems. However, adverse weather situations and disadvantageous illumination conditions like cast shadows have a negative effect on the proper operation of these systems. In this paper, we propose a novel approach for cast shadow recognition in monoscopic color images. In a first step, shadow edge candidates are extracted evaluating binarized channels in the color-opponent and perceptually uniform CIE L*a*b* space. False detections are rejected in a second verification step, using SVM classification and a combination of meaningful color features. We introduce a non-parametric representation for complex shadow edge geometries that enables utilizing shadow edge information for improving downstream vision-based driver assistance systems. A quantitative evaluation of the classification performance as well as results on multiple real-world traffic scenes show a reliable cast shadow recognition with only a few false detections.

Trajectory generation for aircraft subject to dynamic weather uncertainty

Scipedia content — Wed, 03 Feb 2021 20:36:22 +0100

Determining safe aircraft trajectories that avoid hazardous weather regions and other aircraft while efficiently using the available airspace is an important problem. Although tactical weather forecast maps have been available, their use in automated aircraft trajectory generation has not been fully explored or implemented. We consider aircraft trajectory generation using forecast data available from the Corridor Integrated Weather System product. The forecasts, updated at regular intervals, are used to design no-fly regions. We propose a receding horizon trajectory generation based on the dynamic nature of the forecast. Our method uses current environment information and incrementally updated forecast to update and optimize the trajectories. Simulations are shown based on forecast weather and indicate the advantage of taking into account time-varying forecasts in the planning horizon.

Trajectory-Based Takeoff Time Predictions Applied to Tactical Departure Scheduling: Concept Description, System Design, and Initial Observations

Scipedia content — Wed, 03 Feb 2021 20:34:02 +0100

Current aircraft departure release times are based on manual estimates of aircraft takeoff times. Uncertainty in takeoff time estimates may result in missed opportunities to merge into constrained en route streams and lead to lost throughput. However, technology exists to improve takeoff time estimates by using the aircraft surface trajectory predictions that enable air traffic control tower (ATCT) decision support tools. NASA s Precision Departure Release Capability (PDRC) is designed to use automated surface trajectory-based takeoff time estimates to improve en route tactical departure scheduling. This is accomplished by integrating an ATCT decision support tool with an en route tactical departure scheduling decision support tool. The PDRC concept and prototype software have been developed, and an initial test was completed at air traffic control facilities in Dallas/Fort Worth. This paper describes the PDRC operational concept, system design, and initial observations.

Visualization of uncertainty for Air Traffic Controllers

Scipedia content — Wed, 03 Feb 2021 20:30:15 +0100

International audience; The goal of Air Traffic Controllers (ATCo) is to maximize both safety and capacity, so as to accept all flights without compromising the life of the passengers or creating delays. Because air traffic is expected to double by 2030, new IT systems must be developed to manage this traffic increase while maintaining or improving safety. ATCo radar screen displays past, current, and future aircraft position that contains uncertainty without displaying it. Uncertainty is mentally integrated by ATCo when assessing the future aircraft position. In this paper, we give some information regarding the radar data uncertainty and we propose new designs to display future aircraft positions more accurately with their uncertainty.

An introduction to OpenStreetMap and some use in research

Scipedia content — Wed, 03 Feb 2021 20:28:51 +0100

Improving insight in modal choice determinants: an approach towards more sustainable transport

Scipedia content — Wed, 03 Feb 2021 20:28:16 +0100

This paper will discuss how understanding what determinants influence modal choice is important towards developing more sustainable transport systems. An improved knowledge about these factors is vital in tackling the current mobility problems in a more efficient and sustainable way. In order to assist in the understanding and modeling of modal choice decisions a review on modal choice and its determinants is carried out. The data collection strategy for this review is mainly based on a computerized search guided by the search term ‘modal choice’ and mostly covers the last two decades. First of all, it was found that researchers too often rely on a unimodal approach when studying modal choice and this leads to an underestimation of access and exit modes by neglecting other travel modes, which are mainly the softer modes (walking and cycling). Taking into account the sequence of modes within a single trip is therefore needed to analyze daily mobility in a more sustainable and realistic way. Second, the review clearly showed that modal choice is determined by a whole range of factors that are interrelated to a larger or smaller extent. It is often the result of a very compound choice process that can take place consciously or unconsciously and that includes objective as well as subjective determinants. This paper identifies and structures the determinants of importance influencing the modal choice decision. Moreover, improving insight in these influencing factors can assist in developing policy measures that are better adjusted to the current mobility trends in order to create a modal shift towards more sustainable transport modes and therefore reducing environmental impacts.

Multiobjective evolutionary algorithms for intradomain routing optimization

Scipedia content — Wed, 03 Feb 2021 20:26:04 +0100

Evolutionary Algorithms (EAs) have been used to develop methods for Traffic Engineering (TE) over IP-based networks in the last few years, being used to reach the best set of link weights in the configuration of intra-domain routing protocols, such as OSPF. In this work, the multiobjective nature of a class of optimization problems provided by TE with Quality of Service constraints is identified. Multiobjective EAs (MOEAs) are developed to tackle these tasks and their results are compared to previous approaches using single objective EAs. The effect of distinct genetic representations within the MOEAs is also explored. The results show that the MOEAs provide more flexible solutions for network management, but are in some cases unable to reach the level of quality obtained by single objective EAs. Furthermore, a freely available software application is described that allows the use of the mentioned optimization algorithms by network administrators, in an user-friendly way by providing adequate user interfaces for the main TE tasks. FCT - project ref. PTDC/EIA-EIA/115176/2009; grant UMINHO/BII/061/2009

An optimization model for sample day selection in NAS-wide modeling studies

Scipedia content — Wed, 03 Feb 2021 20:18:21 +0100

Future flight Schedules are generated based on air traffic demand forecast for the purpose of aviation planning and performance analysis studies. A selection process needs to be designed and implemented by sampling historical operational data for each fiscal quarter and choosing representative days that best reflect seasonality in terms of a given set of performance metrics. We propose an optimization based solution method for the sample day selection problem, which is formulated as a Mixed Integer Program (MIP). The objective of the MIP is to minimize the weighted difference between the true population and the sample to be selected in terms of the defined metrics subject to a set of constraints including the sample size limit, coverage requirements and other desired properties. An efficient solution algorithm has been implemented using the CPLEX MIP solver. Experiments have been conducted with a wide range of flight data from the recent years. The results from the MIP method provided robust solutions for the sample day selection problem. It is also shown that the method is quite flexible to incorporate additional constraints based on expert knowledge.

Green-aware routing in GMPLS networks

Scipedia content — Wed, 03 Feb 2021 20:16:23 +0100

The increasing amount of traffic in the Internet has been accommodated by the exponential growth of bandwidth provided by the optical networks technologies. However, such a growth has been also accompanied by an increase in the energy consumption and the concomitant green house gases (GHG) emissions. Despite the efforts for improving energy efficiency in silicon technologies and network designs, the large energy consumption still poses challenges for the future development of Internet. In this paper, we propose an extension of the Open Shortest Path First — Traffic Engineering (OSPF-TE) protocol and a green-aware routing and wavelength assignment (RWA) algorithm for minimizing the GHG emissions by routing connection requests through green network elements (NE). The network behavior and the performance of the algorithm are analyzed through simulations under different scenarios, and results show that it is possible to reduce GHGs emissions at the expense of an increase in the path length, and, in some cases, in the blocking probability. The trade-off between emissions and performance is studied. To the authors knowledge, this is the first work that provides a detailed study of a green-aware OSPF protocol.

A Stochastic Modeling and Analysis Approach to Strategic Traffic Flow Management under Weather Uncertainty

Scipedia content — Wed, 03 Feb 2021 20:06:31 +0100

In this article, we introduce a promising framework for representing an air traffic flow (stream) and flow-management action operating under weather uncertainty. We propose to use a meshed queuing and Markov-chain model—specifically, a queuing model whose service-rates are modulated by an underlying Markov chain describing weather-impact evolution—to capture traffic management in an uncertain environment. Two techniques for characterizing flow-management performance using the model are developed, namely 1) a master-Markov-chain representation technique that yields accurate results but at relatively high computational cost, and 2) a jump-linear system-based approximation that has promising scalability. The model formulation and two analysis techniques are illustrated with numerous examples. Based on this initial study, we believe that the interfaced weather-impact and traffic-flow model analyzed here holds promise to inform strategic flow contingency management in NextGen.

Early user participation in the identification of use case scenarios for 'Connected cruise control'

Scipedia content — Wed, 03 Feb 2021 19:56:48 +0100

Connected Cruise Control (CCC) aims to improve throughput in dense commuter traffic on motorways by advising drivers on speed, headway and lane-use via a nomadic human-machine interface. The advice is generated from a prediction of future traffic flow, based on actual traffic-loop data and is transmitted to the in-car platform via 3.5G communication. The systems advantage compared to Cooperative Adaptive Cruise Control (CACC) lies in its potential for rapid implementation and its additional support of lateral driver behaviour. It is important to note that CCC will not have direct control over the car movement. Its beneficial effect is dependent on the driver‘s willingness to comply with the advice. In turn, willingness to comply, in the long term, is also dependent on the perceived benefit of using the system. It is assumed, that to increase both the driver‘s initial willingness to comply and the perceived benefit of using the system, CCC has to reduce the frequency of situations that are seen as most unpleasant by drivers during peak hour traffic. Therefore it is important to understand what these situations are. This study determines the level of frustration caused by driver behaviour in dense motorway traffic, at a lane drop and at an on-ramp/off-ramp. The results help to identify use cases scenarios for driving simulator experiments to ensure that CCC can have a beneficial effect in these situations.

Light Propagation algorithm for aircraft trajectory planning

Scipedia content — Wed, 03 Feb 2021 19:48:26 +0100

Best presentation Award; International audience; The need for increasing air traffic capacity motivates 4D trajectory planning concept. In order to generate conflict-free 4D trajectories, we introduce a new concept based on light propagation modeling algorithm. This algorithm is a wavefront propagation method that yields a natural solution for the path planning problem specifically in the case of air traffic congestion.

Short-term forecasting in road evacuation: calibration of a travel time function

Scipedia content — Wed, 03 Feb 2021 19:34:02 +0100

The objective of this paper is to present a framework to define a function for estimating within-day variations of travel time on a network. The framework integrates two main components: a within-day traffic assignment model that simulates the interaction between travel demand flows and the road transport network and a dynamic vehicle routing model that provides optimal routes of emergency vehicles. The variable linking the two models is the short-term forecasted travel time, making it possible to capture anticipatory information on traffic dynamics on the network in evacuation conditions.

Monitoring Oil and Gas Facilities: Use of Natural Reflectors and Artificial Corners Reflectors

Scipedia content — Wed, 03 Feb 2021 19:26:49 +0100

InSAR based ground motion monitoring of oil and gas facilities, including pipelines, plants and LNG terminals, contributes to production planning and the safety of operations. Factors such as seismicity, landslides, coastal erosion or anthropogenic effects such as the oil and gas activities themselves may cause infrastructure to be affected by ground motion, which may in turn pose a threat to the surrounding population and wildlife, or the efficiency of the infrastructure itself. The PSI technique is an efficient tool for assessing and monitoring the effects of the aforementioned on the infrastructure and the surrounding area.

Convective Weather Avoidance Modeling in Low-Altitude Airspace

Scipedia content — Wed, 03 Feb 2021 19:25:02 +0100

Thunderstorms are a leading cause of delay in the National Airspace System (NAS), and significant research has been conducted to predict the areas pilots will avoid during a storm. An example of such research is the Convective Weather Avoidance Model (CWAM), which provides the likelihood of pilot deviation due to convective weather in a given area. This paper extends the scope of CWAM to include low-altitude flights, which typically occur below the tops of convective weather and have slightly different operational constraints. In general, the set of low-altitude flights includes short-hop routes and low-altitude escape routes used to reduce the impact of convective weather in the terminal area. This paper will discuss the classification procedure, present the performance of low-altitude CWAM on observed and forecasted weather, analyze areas of poor performance, and suggest potential improvements to the model. I. Introduction ONVECTIVE weather is a significant impediment to effective and efficient Air Traffic Management (ATM) decisions, and sometimes results in unnecessary delays to the National Airspace System (NAS). In the NAS, 70% of delays are caused by weather, and of those delays, 60% are specifically accounted for by convective weather [1]. Currently, rerouting decisions made by air traffic managers are aided by weather products such as the Corridor Integrated Weather System (CIWS) and the National Convective Weather Forecast (NCWF) [2, 3]. In a Next Generation ATM system, decision support tools such as the Route Availability Planning Tool (RAPT) will mitigate weather-induced delays by supplementing the situational awareness of an air traffic manager with a forecast of the availability of specific flight routes [4]. RAPT is based on the Convective Weather Avoidance Model (CWAM), which is a probabilistic model of pilot decision making in the presence of convective weather [5]. CWAM is a tool originally developed for the en route flight regime to predict pilot deviation decisions by correlating in-flight deviations of aircraft to the weather features they encounter. The model is based on a database comprised of the deviation decision of each flight and weather statistics along each route, which are obtained from CIWS. Pattern classification experiments on the en route CWAM database show that the most descriptive predictors for deviation are related to echo top height, where the most descriptive is the difference in altitude between the aircraft and the echo top height [5]. In the terminal area, deviations are predicted with a different set of features. Several studies of the Dallas and Memphis areas using weather information from the Integrated Terminal Weather System (ITWS) show that deviation decisions are closely related to the radar intensity of the storm and the proximity of the aircraft to the airport [6, 7]. This paper presents the development of a low-altitude version of CWAM which is based on a database composed of weather encounters that occur during level flight between FL100 and FL240. This model is applicable to jet traffic that uses low altitude air routes to „escape‟ from terminal areas when weather or volume congestion impacts lead to constraints on high-altitude airspace, or to low-altitude flight by regional jets on „short hop‟ routes. Such traffic is common in major metroplex airspaces. In this analysis, flight trajectories are obtained from the Enhanced Traffic Management System (ETMS) database, and weather data are acquired from CIWS for 23 convective weather days across two geographical regions (Chicago and New York). A Gaussian classifier is used to determine a set of deviation predictors and the results are tested on observed and forecasted data. The predictor performance is compared to the existing terminal departure CWAM used in RAPT, and the differences are discussed.

Innovative Joint Proves Successful in Critical Slipline Project

Scipedia content — Wed, 03 Feb 2021 19:18:31 +0100

Ever-tightening budgets are forcing water system owners to rehabilitate their major water transmission mains with permanent solutions, a key approach in their asset management programs. Halifax Water was recently faced with a deteriorating Prestressed Concrete Cylinder Pipe (PCCP) water transmission main that needed rehabilitation or replacement. This transmission main is located under Kearney Lake Road, a main high traffic level corridor on the west side of Halifax. The use of Spirally Welded Steel Pipe (WSP) with a unique O-ring rubber-gasket joint, allowed Halifax Water to successfully rehabilitate 4,920 LF (1.5 km) of a 48-inch (1200 mm) host PCCP primary transmission main by sliplining. This fully structural lining system provided a structurally independent solution designed to last 100 years. This paper details the innovative use of polyurethane lined and coated Steel Pipe with the unique joint that eliminated liner pipe bells and ensured that maximum internal flow area was provided by the lining system. OVERVIEW Halifax, Nova Scotia, not unlike numerous other municipalities in North America, developed their water transmission system using Prestressed Concrete Cylinder Pipe (PCCP). Beginning in 1952, Halifax began the development of the Pockwock Water Supply system to support the growing industrial and cultural dynamics of metro Halifax. In 1977, the Pockwock Water Supply system was brought online to provide high quality water and service to the taxpayers of Halifax. A primary water transmission main from one of the nine water supply plants operated by Halifax Water was constructed in 1977 along Kearney Lake Road, a major thoroughfare serving the west side of metro Halifax. This transmission main ranged in diameter from 30 inch (1050 mm) to 60 inch (1500mm). In the late 1980’s and throughout the 1990’s there were several major failures along the Kearney Lake Road transmission main. Halifax Water began repairs on this pipeline through the use of conventional open cut pipe removeand-replace methods. In 2001, construction began to twin approximately 5000 LF (1.5 km) of the pipeline along the areas that had failed over the last several years. This twining program was instituted because of growing concerns about the performance ability of this line over time. SOLUTION ALTERNATIVES In 2005, Halifax Water contracted with the Pressure Pipe Inspection Company (now owned by Pure Technologies) to use their Prestressed Concrete Cylinder Pipe PCCP assessment technology. The condition assessment program identified numerous prestressing wire breaks along the transmission main. These wire breaks created performance concerns and were repaired. Then in 2006 and 2007 respectively, two additional catastrophic failures occurred on this line. The latter failures demanded 1 Northeastern Regional Sales Manager, Northwest Pipe Company, 1050 N. State St. Mezzanine Suite 7, Chicago, IL 60610; Tel: (312)587-8702; Email: tbaas@nwpipe.com 2 Engineering Manager, Northwest Pipe Company, 183 Northwest Drive, Washington, WV 26181; Tel: (304)863-3316 ext. 4904; Email: jgardner@nwpipe.com 3 Director of Engineering, Northwest Pipe Company, 5721 SE Columbia Way, Suite 200, Vancouver, WA 98661, Tel: (360) 397-6250, E-mail: rmielke@nwpipe.com 644 Pipelines 2011: A Sound Conduit for Sharing Solutions © ASCE 2011

Improved Concentric Thread Connectors for SCRs and Pipelines

Scipedia content — Wed, 03 Feb 2021 19:12:54 +0100

Modeling the Controller's Conflict Detection Task Using Fast Time Simulation

Scipedia content — Wed, 03 Feb 2021 19:07:29 +0100

International audience; This paper shows how the CATS (Complete Air Traffic Simulator) can model the controller¡¯s conflict detection task using a sliding time window. Because of uncertainties, detection is by far the most time consuming and cognitively challenging aspect of air traffic control. The processes governing detection are distinct from resolution actions. Few conflicts detected lead to a resolution maneuver. Because future aircraft positions are uncertain, controllers detect many more conflicts or "potential conflicts" than actually occur. In this paper, we solve conflicts in a real time context and compare different uncertainty scenarios. We show how uncertainties impact the number of theoretical potential conflicts detected and the increase the number of unnecessary maneuver actions required to keep the traffic safe. When we deal with realistic uncertainty values, the majority of calculation time in CATS is used for calculating maneuvers that will usually not be transmitted to pilots. This observation reveals the true nature of the controller¡¯s workload today.

Route Availability Planning Tool Evaluation Visualizations for the New York and Chicago Departure Flows

Scipedia content — Wed, 03 Feb 2021 19:06:18 +0100

When operationally significant weather affects a region of the National Airspace System (NAS) a Severe Weather Avoidance Program (SWAP) is initiated for that region. Each SWAP event is a unique mix of demand, weather conditions, traffic flow management (TFM) initiatives and traffic movement. On the day following a SWAP, the SWAP events are reviewed by FAA and airline representatives as part of the daily planning teleconference, and the TFM initiatives used are evaluated to understand their impact on the traffic flows, benefits, and disadvantages. Due to the complexity of the situation various exploratory visualizations were designed in order to evaluate aspects of the aviation environment and the responsive actions of the NAS during outbreaks of convective weather as well as to gain insights on the interaction of weather and traffic operations. From these visualizations, analyses and metrics were developed that could be used to objectively evaluate the effectiveness of TMIs. This paper will present three visualizations that have directly resulted in the development of analyses for TMIs or lead to insights into air traffic operations.

Fuel efficiency driver assistance system for manufacturer independent solutions

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

Energy efficiency has become a major issue in modern trade, business and environmental perception. While the next generation of zero emission propulsion systems are still under development, it is already possible to increase fuel efficiency in regular vehicles by applying a more fuel efficient driving behaviour. This particularly holds true for transport companies, where even small percentage savings can accumulate to huge absolute savings. Although there are common fuel efficiency guidelines, they are often imprecise and not adapted to a specific vehicle. Furthermore drivers may not even know the fuel efficiency rules or lack the motivation to apply them in practice. In this paper, an online driving assistance system is presented that assist drivers during their journeys by giving them fuel efficiency guidelines that are suited for the current situation and vehicle. The driver assistance system uses an internal manufacturer independent model that can adapt to the current vehicle solely based on online CAN-Bus data.

An empirical study on the interactions between ALTO-assisted P2P overlays and ISP networks

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

The recently proposed Application Layer Traffic Optimization (ALTO) framework has opened up a new dimension for Internet traffic management that is complementary to the traditional application-agnostic traffic engineering (AATE) solutions currently employed by ISPs. In this paper, we investigate how ALTO-assisted Peer-to-Peer (P2P) traffic management functions interact with the underlying AATE operations, given that there may exist different application-layer policies in the P2P overlay. By considering specific P2P peer selection behaviors on top of a traffic-engineered ISP network, we conduct a performance analysis on how the application and network-layer respective performance is influenced by different policies at the P2P side. Our empirical study offers significant insight for the future design and analysis of cross-layer network engineering approaches that involve multiple autonomous optimization entities with both consistent and non-consistent policies.

Common Pitfalls in Hydraulic Design of Large Diameter Pipelines: Case Studies and Good Design Practice

Scipedia content — Wed, 03 Feb 2021 18:49:02 +0100

When designing large diameter water transmission pipelines, some engineers rely on design rules-of-thumb or a previous project as a template, without recognizing the inherent differences of each project. For large-scale water supply projects, mistakes in hydraulic design, especially underestimating friction headlosses, can be magnified resulting in reduced system capacities, catastrophic failures, or potential litigation. One of the most common mistakes in hydraulic design of large-diameter pipelines is underestimating pipe resistance and friction headlosses. The Hazen-Williams equation is the most widely used method for calculating headlosses in pipelines because it is simple and easy to use. However, the Hazen-Williams equation is empirical and, for large-diameter pipelines, has a limited range of applicability. Conversely, the Darcy-Weisbach equation provides a better approximation of friction headlosses since it takes into account the pipe roughness and Reynolds Number for different pipe materials, and is valid for all pipe sizes and turbulent flow ranges. Although there is an abundance of evidence of the limitations of the Hazen-Williams equation, it is continually misused in the engineering industry. There are many other design issues that can cause serious performance problems with large-diameter pipeline projects if not taken into consideration during design. Additional common hydraulic design pitfalls include: underestimating effects of sediment and biological material in raw water sources, not accounting for aging of pipeline materials, inadequate pipe pressure class design, improper placement and sizing of air valves, lack of accurate transient and surge analysis, inadequate flow and pressure field measurement, and potential need for pipeline maintenance and cleaning. There have been numerous publications on the topic of hydraulic design and proper calculation of pipeline friction headlosses. However, the focus of this paper is to provide analysis through case studies of several major water supply systems that reaffirms the importance of utilizing proper hydraulic considerations. Common hydraulic design oversights and short-cuts can often result in capacity and maintenance problems for large water supply systems.

A legal safety concept for highly automated driving on highways

Scipedia content — Wed, 03 Feb 2021 18:43:19 +0100

International audience; This paper discusses the design of an Advanced Driver Assistance System (ADAS) that ensures safety when traffic rules are respected by all road users. This concept, referred to as legal safety, is proposed as a basis that permits human and automated drivers to share the road infrastructure. It is illustrated for a Highly Automated driving System with speed keeping, distance keeping and lane changing functionalities on highways (HAS). The requirements legal safety places upon HAS components are presented, with a special focus on the co-pilot which calculates a safe trajectory for the vehicle based on perception of lanes and traffic signs and prediction of the trajectories of objects in the environment. A lane coordinate system is proposed as a powerful reference for the trajectory calculations of the co-pilot. The system controls the vehicle and communicates with the driver, according to an automation mode scheme inspired by the horse-rider metaphor (H-metaphor).

Decision support system for the design of sustainable demand responsive transport

Scipedia content — Wed, 03 Feb 2021 18:37:50 +0100

The provision of traditional public transport services in rural areas have shown to be very inefficient and ineffective. In fact, rural areas are naturally categorized by low levels of population density leading to complex demand patterns (low levels and high spatial and temporal dispersion), which leads to low levels of service of conventional transport services (low frequencies, usage of old vehicles, etc). Demand Responsive Transport systems have been seen as an effective alternative solution already adopted in several countries. There are however some issues concerning DRT costs and benefits that still have to be addressed. In this research work an integrated analysis incorporating both internal and external costs is proposed aiming to support decision makers investigating the impacts and performance measures related to the adoption of a flexible transportation system solution. Additionally, DRT systems are highly dependent on the correct calibration of some organizational and functional parameters. In this paper, a comprehensive framework to support decision-makers in the design and planning of flexible transportation systems is proposed. The developed approach allows the simulation of different scenarios corresponding to different design alternative solutions. Accurate estimation of their global performance, in terms of both viability and sustainability, can be obtained providing effective support in the design and operational stages of a DRT system implementation in low density areas. Fundação para a Ciência e a Tecnologia (FCT) COMPETE - QREN

Integrating formal verification and high-level processor pipeline synthesis

Scipedia content — Wed, 03 Feb 2021 18:36:25 +0100

When a processor implementation is synthesized from a specification using an automatic framework, this implementation still should be verified against its specification to ensure the automatic framework introduced no error. This paper presents our effort in integrating fully automated formal verification with a high-level processor pipeline synthesis framework. As an integral part of the pipeline synthesis, our framework also emits SMV models for checking the functional equivalence between the output pipelined processor implementation and its input non-pipelined specification. Well known compositional model checking techniques are automatically applied to curtail state explosion during model checking. The paper reports case studies of applying this integrated framework to synthesize and formally verify pipelined RISC and CISC processors.

Indicators for sustainable mobility in the cities

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

The creation of a sustainable transport system is the main objective of the European transport policy. This system should encourage facilities to connect all people and should be linked with economic, social and environmental aspects of society. Current trends and future challenges will meet a growing “accessibility” demand, highlighting concerns about the sustainability of transport. Therefore one of the priorities of transport policy is the improving of overall quality of transport, including aspects related to: personal safety, accidents and health hazards reduction, protection of passengers rights and of accessibility to remote areas. This paper is dedicated to sustainable development, with particular attention to urban transport and to daily mobility of citizens. It is important to analyze all the aspects that make it possible to clarify a definition of “sustainable transport”. Their analysis has to be related to the individuation of a set of indicators that simultaneously take into account the three dimensions of sustainability: environment, economy and social issues. This, set should help to take decisions on policy and planning of urban transport systems. A limited and easily available set of indicators is more convenient to be used, but it may overlook important impacts, thus distorting planning decisions. A broad set of indicators can propose more quality in terms of completeness, but it has characterized by incredible data collection costs and by serious difficulties of interpretation. This study is based on the results of a survey carried out to verify feasibility and usefulness of such indicators for sustainable urban mobility in a particular territory. Values assumed by economic, environmental and social indicators are referred to the city of Palermo. A survey on family shifts was carried out in this city. It aims to the creation of a set of indicators that would allow comparison between different urban transport strategies. Finally, we analyze the possibility to generalize the proposed

Comparison of the Mechanical Properties of Steel and Ductile Iron Pipe Materials

Scipedia content — Wed, 03 Feb 2021 18:31:58 +0100

Water infrastructure engineers commonly evaluate a variety of pipe materials to determine the most appropriate solution for a particular application. Occasionally engineers inappropriately apply identical structural design criteria for both steel and ductile iron pipe (DIP). While similarities do exist, there are substantial differences in the material properties that make their structural designs unique. The applicable AWWA standards and design manuals are evidence of such variances. To demonstrate the distinguishing mechanical properties of steel and ductile iron, large diameter samples were gathered, cut, and subjected to mechanical property testing. A review of the results will validate the existence of distinct material properties and clearly indicate the need for unique design practices that should not be modified or comingled. The mechanical property differences between steel and ductile iron and the implications to applicable AWWA design criteria are discussed.

Runway Scheduling Using Generalized Dynamic Programming

Scipedia content — Wed, 03 Feb 2021 18:31:33 +0100

y, the runway scheduling problem (RSP) can be thought of as a job shop scheduling problem [11] withprecedence and release time constraints, where the objective is to sequence a set of jobs (aircraft) in a particularordertobeprocessedbyaprocessor(runway)sothatsomecostfunctionisminimized. Fortherunwayschedulingproblem, one wants to ﬁnd an eﬃcient schedule for aircraft to use the runway. The output, then, to the runwayscheduling problem is a time for each aircraft to begin using the runway, which will be referred to as a runwayschedule.Therunwayschedulingproblemisformallydescribedasfollows: Givenanorderedsetofdepartureaircraft Q d foreachdeparturequeue d ,asetofdepartureaircraft G g foreachgate g ofcardinality1,anorderedsetofaircraft C c foreachrunwaycrossingqueue c ,asetofaircraft P i thatmustnotusetherunwaybeforeaircraft i ,anearliesttime α ( i )foraircraft i toreachtherunway,andvarioustimingconstraints(describedbelow),ﬁndthesetof non-dominating a runwayschedule(s)withrespecttobothdelayandthroughput.A diagram of a typical problem is shown below in Figure 1. This diagram shows an example airport with onedeparture runway, a ramp area, and a network of taxiways. Each aircraft on the airport surface waits to use therunwayinchainlikestructurescalledqueues. Forthisdiagram,departureaircraftlocatedwithintherampareaareattheirgatesorgatequeues,anddepartureaircraftnearthetopleftentranceofthedeparturerunwayarewaitingindeparturequeues. Finally,thereisonetaxiwaythatcrossestherunwaywithachainoftwoaircraftwaitingcross.Theseaircraftwaitingtocrosstherunwayaresaidtobewaitingintheircrossingqueue.Tobeexact,anaircraf

Evaluation of the Monotonic Lagrangian Grid and Lat-Long Grid for Air Traffic Management

Scipedia content — Wed, 03 Feb 2021 18:25:17 +0100

The Air Traffic Monotonic Lagrangian Grid (ATMLG) is used to simulate a 24 hour period of air traffic flow in the National Airspace System (NAS). During this time period, there are 41,594 flights over the United States, and the flight plan information (departure and arrival airports and times, and waypoints along the way) are obtained from an Federal Aviation Administration (FAA) Enhanced Traffic Management System (ETMS) dataset. Two simulation procedures are tested and compared: one based on the Monotonic Lagrangian Grid (MLG), and the other based on the stationary Latitude-Longitude (LatLong) grid. Simulating one full day of air traffic over the United States required the following amounts of CPU time on a single processor of an SGI Altix: 88 s for the MLG method, and 163 s for the Lat-Long grid method. We present a discussion of the amount of CPU time required for each of the simulation processes (updating aircraft trajectories, sorting, conflict detection and resolution, etc.), and show that the main advantage of the MLG method is that it is a general sorting algorithm that can sort on multiple properties. We discuss how many MLG neighbors must be considered in the separation assurance procedure in order to ensure a five-mile separation buffer between aircraft, and we investigate the effect of removing waypoints from aircraft trajectories. When aircraft choose their own trajectory, there are more flights with shorter duration times and fewer CD&R maneuvers, resulting in significant fuel savings.

Challenges to Modeling Vectored Area Navigation Departures at Dallas/Fort Worth International Airport

Scipedia content — Wed, 03 Feb 2021 18:21:51 +0100

This paper analyzes both air traffic volume and controller motivations while attempting to correlate these factors to the vectoring of area navigation (RNAV) departures at Dallas/Fort Worth International Airport (DFW). One-third of DFW RNAV departures encounter some form of vectoring away from the RNAV routes. The majority of those vectored, about one-quarter of all the departures, are given direct routings that bypass fixes on the route and shorten the distance flown within the DFW Terminal Radar Approach Control (TRACON) airspace. Understanding when and why vectoring occurs gives researchers further insight into the complex dynamics of super dense airspace operations which can be used to improve trajectory prediction for automated decision support tools. This paper describes the development of models aimed at understanding and modeling those instances. The results of these models’ development show they are not good predictors of short cuts, as they fail to capture controllers’ decision-making criterion for vectoring. The interviews with retired TRACON controllers, however, provided other data to consider or to obtain that might improve the modeling. These interviews also indicate the subjectivity of their decisions to vector these aircraft in clear conditions and highlight the complexity of air traffic in super-dense airspace.

Modeling conflicts resolution of Unmanned Aircraft System using a lightweight Duration Calculus

Scipedia content — Wed, 03 Feb 2021 18:21:38 +0100

Over the last two decades, an interesting area of Brazilian military and civil sectors is the Unmanned Aircraft Vehicle (UAV) development. This article tackles the modeling of conflicts resolution of Unmanned Aircraft System (UAS) using a lightweight Duration Calculus (DC) to verify if the temporal specification and design of the system is correct and to ensure formally that the system implementation meets all its requirements. Moreover, the article proposes a formal modeling (using DC) of a conflicts resolutions set of rules, adapted from Free Flight concept in Communications, Navigation and Surveillance/Air Traffic Management (CNS/ATM). In the adapted approach to UAS, each UAV is surrounded by an imaginary space of two cylinders, which form, respectively, the protected zone and the alert zone. The major contribution of this article is structuring a new scenario application of the conflicts resolution to UAS through formal modeling, using the DC technique to confirm that the models could be implemented without deadlocks and unreachable states, as well as with satisfaction of temporal restrictions. Furthermore, this work uses the state-of-the-art practices in formal methods, including a model checking tool to ensuring correct real-time requirements specification of a real-time critical system.

State of the art in airport navigation

Scipedia content — Wed, 03 Feb 2021 18:20:43 +0100

The general increase in air traffic and the complexity of modern airport layouts have conducted to think about new technologies to assist pilots during maneuvers on airport surface. Some airport navigation applications have been developed in recent years. The current technologies plot the estimated aircraft position on the airport map. In good visibility condition, this information helps the pilot to navigate on the airport. These applications contribute to the reduction of the taxiing time and runway incursions. Nevertheless, this information is not sufficient to navigate in low visibility condition. This paper introduces the state of the art in airport navigation, with the current functions available to assist pilots, and also the additional applications envisaged to improve the airport navigation in low visibility condition. Current constraints and limitations of airport navigation development are highlighted.

Power Generation Case Study: Feasibility of Carbon Fiber and Alternate Repair Methods

Scipedia content — Wed, 03 Feb 2021 18:20:07 +0100

coal fired Power Generation Facility in the Baltimore relies on a large diameter circulation pipeline stretching half a mile from the boiler to the cooling towers. The line was constructed with mainly 102 Prestressed Concrete Cylinder Pipe (PCCP) containing problematic class IV wire. The plant started experiencing breaks in the nineties with costly repairs and even more costly lost revenue. The plant engineers then devised a proactive inspection and preventive repair program that managed to mitigate breaks but still forced longer outages and costly repairs using post-tensioning loops or concrete encasements. In 2007, a solution was presented which included the use of Fiber Reinforced Polymer, or Fiber Wrap. The advanced composite system was applied on the interior of the pipelines at this facility first in the fall of 2007. After that first successful experience, internal repairs utilizing Fiber Wrap became common practice for dealing with distressed pipes as they were detected year after year. The Power Generation facility went beyond the year to year approach and in 2009 decided to strengthen the entire length under the switchyard to completely eliminate the chance that a break or a leak would shut down the entire plant. The scope of work for this Project, completed in early 2010, was 55 sections, 20 ft long and 102 diameter to complete in 30 days. The project included a very short window for surface preparation of 10 days. The completion of the Fiber Wrap installation and top coating was reached on day 24 of the project, well ahead of a very challenging schedule. Alternative methods of mitigating this critical pipeline problem could have cost up to 5 times the Fiber Wrap option and would have caused major construction to take place under rail lines. The application of Fiber Wrap can be completed in 10–15% of the time required to replace pipelines of this nature. For over a decade Fiber Wrap has been utilized to strengthen and renew pipelines in varying degrees of distress and degradation in the municipal water and power generation market. The process is viable when there is an inability to excavate and a trenchless method must be utilized. Fiber Wrap liners lend themselves well to trenchless rehabilitation where a fully structural solution is a requirement. The Fiber Wrap designs may consider various loading combinations from internal pressure to external loads such as vehicular traffic, or in some cases, train traffic. The Fiber Wrap liner used as a segmental repair in combination with electromagnetic wire break testing for PCCP or Ultra Sonic(UT) testing for steel wall thickness loss may be a more economically feasible repair method when pipeline owners are working with limited rehabilitation budgets. The case study will present a clear contrast of various methods of pipeline repair considering the associated costs of down time, environmental impact, safety and capacity loss. Using the Power Generation facility project as a detailed case study this paper will assist pipeline owners in determining if and when to consider the use of Fiber Wrap. It will present a concise and objective comparison and contrast to traditional pipeline upgrade meant to provide Conference attendees usable information to assist in making these critical operational and financial decisions.

Efficiency Benefits Using the Terminal Area Precision Scheduling and Spacing System

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

NASA has developed a capability for terminal area precision scheduling and spacing (TAPSS) to increase the use of fuel-efficient arrival procedures during periods of traffic congestion at a high-density airport. Sustained use of fuel-efficient procedures throughout the entire arrival phase of flight reduces overall fuel burn, greenhouse gas emissions and noise pollution. The TAPSS system is a 4D trajectory-based strategic planning and control tool that computes schedules and sequences for arrivals to facilitate optimal profile descents. This paper focuses on quantifying the efficiency benefits associated with using the TAPSS system, measured by reduction of level segments during aircraft descent and flight distance and time savings. The TAPSS system was tested in a series of human-in-the-loop simulations and compared to current procedures. Compared to the current use of the TMA system, simulation results indicate a reduction of total level segment distance by 50% and flight distance and time savings by 7% in the arrival portion of flight (~200 nm from the airport). The TAPSS system resulted in aircraft maintaining continuous descent operations longer and with more precision, both achieved under heavy traffic demand levels.

The Passenger Stock and Attractivity Threshold for transit assignment with capacity constraints

Scipedia content — Wed, 03 Feb 2021 18:10:29 +0100

actes sont disponibles en ligne et sur DVD (payant) http://amonline.trb.org/; International audience

Latest Advances in Pipeline Renovation with Fiber Reinforced Polymer (FRP)

Scipedia content — Wed, 03 Feb 2021 18:05:36 +0100

There has been a growing interest in the use of Fiber Reinforced Polymer (FRP) for repair and strengthening of structures, including pipelines in recent years. This paper focuses on the development of a new generation of FRP products called SuperLaminate. These sheets are produced in manufacturing plants per design specifications to meet the strength and stiffness requirements of the particular project. The products are stronger than conventional FRP and are installed in significantly less time. Among the applications are strengthening of pressurized pipes, repair of corrugated metal pipe culverts and joints in water and sewer pipes. A single roll can be used to repair any diameter pipe, making this a very versatile product.

A Time-Space diagram as controller support tool for closed path Continuous descent operations

Scipedia content — Wed, 03 Feb 2021 17:56:42 +0100

Tactical control during a closed-path Continuous Descent Operation stops the aircraft from following its optimized descent. To mitigate tactical control, air traffic controllers apply arbitrary large spacing buffers to account for the unpredictability of the aircraft trajectory from the controller’s point of view. A controller support tool is required for early de-confliction, spacing, and sequencing to facilitate these operations without the need to apply large buffers. The Time-Space Diagram controller support tool was developed to make the constraints and complexity of a Continuous Descent Operation perceptually evident and provide tools and information to the controller to be an active problem solver. This paper addresses the further development and validation of the interface. The concept of Visual Momentum was applied to enhance the efficiency of working the multi-display interface that consists of the Plan View Display and Time-Space Diagram. Direct Manipulation Interfaces were added to enable the controller to plan and implement actions, such as speed and altitude control. A controller-in-the-experiment was setup to validate the interface. In the experiment the subjects used either the Time-Space Diagram support tool or a stack list that provided the required spacing and time to lose or gain as a baseline. Both interfaces enabled the subjects to space the aircraft safely and efficiently. Compared to the baseline, the Time-Space Diagram interface freed time to plan traffic ahead using the Direct Manipulation Interfaces, which according to all subjects worked intuitively. The number of instructions per aircraft was decreased by 25%. Early accurate speed control was applied and use of heading vectors was no longer necessary in most scenarios. As a result aircraft commenced their continuous descent at a higher altitude and greater distance from the runway. The controller workload was significantly reduced and the level of Situational Awareness increased.

A lighting study for air traffic control towers

Scipedia content — Wed, 03 Feb 2021 17:54:16 +0100

The purpose of this work was to determine the characteristics of glass and natural and artificial lighting systems capable of achieving, within the operating rooms of the air traffic control towers, the optimal conditions in terms of visual performance and comfort, within a framework established by law, from energy conservation, the availability of materials, ease of maintenance, security. The solutions identified, although the result of a compromise between different environmental and functional requirements often conflict with each other, were still subject to the need to ensure the proper and safe view of the external environment by air traffic controllers. The methodology, given the complexity of the problems arising from the interaction between various parameters, is based on different and successive levels of detail, each of which is in preparation of the next. In particular, starting from a lumped parameter-analysis that considers only the global aspects of the problem and identifies the main characteristics of materials and systems used, is followed by a study of distributed parameter to analyze in detail the visual aspects and solutions possible, before arriving in the creation of design specifications whose validity has been verified by studying a case type. The different levels of analysis can be summarized as follows: 1. Lumped parameter analysis 2. Distributed parameter analysis: visual environment 3. Distributed parameter analysis: case study

Hydraulic Transient Computer Model for San Diego Water Authority

Scipedia content — Wed, 03 Feb 2021 17:43:47 +0100

San Diego County Water Authority is a water wholesaler providing a safe and reliable water supply to its 24 member agencies in the San Diego region. The Water Authority supplies up to 90% of San Diego County's water, which serves more than 3 million residents. The water supply system includes approximately 300 miles of open channel and pressurized pipelines, ranging from 48 to 108 inches in diameter, 103 active meter connections, 7 pumping stations, 4 hydroelectric facilities, one water treatment plant, and one reservoir. These facilities were constructed over the last 60 years through a sequence of individual projects, resulting in a complex hydraulic distribution system. DHI, Inc. and Franklin DeFazio, Inc. have been working together to develop a dynamic transient flow model that will be suitable for modeling the Water Authority's conveyance and distribution system. The dynamic transient simulation model will also be used to analyze and simulate relevant appurtenant facilities of other local agencies that have a significant hydraulic influence upon the Water Authority's system. The work includes modification to an existing Hydraulic Transient Engine known as FG3D (Flow Gradient Dynamics Inc.) which is incorporated into a MIKE URBAN (DHI, Inc.) hydraulic model to provide an integrated modeling system. The project includes substantial programming of menus and tools, as well as additional functionality in the Transient Model code. The transient model will be verified on pilot reaches, including the Second Aqueduct untreated water pipelines from Twin Oaks Valley Flow Regulatory Structure (TOVFRS) to Otay Lake (135 miles) in conjunction with the Olivenhain Pipeline and Pump Station. The outline of this ongoing project, as well as the experience from hydraulic transient computing and development is discussed in this paper.

Method for stereo mapping based on ObjectARX and pipeline technology

Scipedia content — Wed, 03 Feb 2021 17:43:25 +0100

Stereo mapping is an important way to acquire 4D production. Based on the development of the stereo mapping and the characteristics of ObjectARX and pipeline technology, a new stereo mapping scheme which can realize the interaction between the AutoCAD and digital photogrammetry system is offered by ObjectARX and pipeline technology. An experiment is made in order to make sure the feasibility with the example of the software MAP-AT (Modern Aerial Photogrammetry Automatic Triangulation), the experimental results show that this scheme is feasible and it has very important meaning for the realization of the acquisition and edit integration.

On the Evaluation of Urban Logistics Intermodal Terminal Projects

Scipedia content — Wed, 03 Feb 2021 17:39:24 +0100

This paper is looking to incorporate uncertainty and risk in the financial assessment of an urban logistics investment project - a ""rail-road" intermodal terminal performing urban logistic distribution functions. A "cost benefit analysis" (CBA) is performed for four decision scenarios (with different destinations and technologies). The variables included in the CBA are treated as random variables with different distribution functions (uniform, binomial, normal). The net present value (NPV) used to rank the different decision scenarios is based on results from a Monte Carlo simulation. NPV obtained as a discrete variable has been used to evaluate risk (expressed with specific indicators) and for the comparison with a NPV of a similar project in operation. A comparison with CBA that expresses NPV deterministically and the "states of nature" with known probabilities is made. Under uncertainty conditions (the "states of nature" completely unknown) the preferences of the decision maker are analysed for a certain scenario depending on his/her attitude towards risk (cautious, optimistic, pessimistic). The CBA is complemented by a "cost-efficacy analysis" (CEA) which reflects the manner in which the non-financial, social consequences of the project can be used to rank the decision scenarios. In conclusion, the paper pleads for the professionalism required by CBA and CEA, when risk and uncertainty cannot be ignored, this being the case of most infrastructure investments with social implications difficult to estimate financially. Refereed/Peer-reviewed

Lane change intent prediction for driver assistance: On-road design and evaluation

Scipedia content — Wed, 03 Feb 2021 17:37:29 +0100

utomobiles are quickly becoming more complex as new sensors and support systems are being added to improve safety and comfort. The next generation of intelligent driver assistance systems will need to utilize this wide array of sensors to fully understand the driving context and situation. Effective interaction requires these systems to examine the intentions, desires, and needs of the driver for preemptive actions which can help prepare for or avoid dangerous situations. This manuscript develops a real-time on-road prediction system able to detect a driver's intention to change lanes seconds before it occurs. In-depth analysis highlights the challenges when moving intent prediction from the laboratory to the road and provides detailed characterization of on-road performance.

Girgit: A Dynamically Adaptive Vision System for Scene Understanding

Scipedia content — Wed, 03 Feb 2021 17:36:15 +0100

International audience; Abstract. Modernvisionsystemsmustrunincontinuallychangingcontexts.For example, a system to detect vandalism in train stations must function during the day and at night. The vision components for acquisition and detection used dur- ing daytime may not be the same as those used at night. The system must adapt to a context by replacing running components such as image acquisition from color to infra-red. This adaptation must be dynamic with detection of context, decision on change in system configuration, followed by the seamless execution of the new configuration. All this must occur while minimizing the impact of dy- namic change on validity of detection and loss in performance. We present Girgit, a context-aware vision system for scene understanding, that dynamically orches- trates a set of components. A component encapsulates a vision-related algorithm such as from the OpenCV library. Girgit inherently provides loading/caching of multiple component instances, system reconfiguration, management of incoming events to suggest actions such as component re-configuration and replacement of components in pipelines. Given the surplus architectural layer for dynamic adap- tation one may ask, does Girgit degrade scene understanding performance? We perform several empirical evaluations on Girgit using metrics such as frame-rate and adaptation time to answer this question. For instance, the average adaptation time between change in configurations is less than 2 μs with caching, while 8 ms without caching. This in-turn has negligible effect on scene understanding perfor- mance with respect to static C++ implementations for most practical purposes.

Modeling and Simulation of the Impact of Air Traffic Operations on the Environment

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

traffic affects the environment locally, regionally, and globally. Recent studies indicate an increased urgency to understand and mitigate the impact of air traffic on climate. Greenhouse gases...

Impact of Electric Vehicles on power quality in a Smart Grid context

Scipedia content — Wed, 03 Feb 2021 17:25:23 +0100

The large dependency of the imported fossil fuels and the soaring oil prices, makes essential the look for alternatives to the traditional people transportation system. The natural bet is the electric mobility, namely Electric Vehicles (EV), and Plug-in Hybrid Electric Vehicles (PHEV). This way, in this paper is analyzed the potential impacts of the battery charging systems on the grid power quality, in a Smart Grid context. It is considered the current consumed, according to a typical electric consumption profile, and the voltage degradation for a large number of houses. Two different types of EV batteries chargers were considered: a traditional charger; and a smart charger with sinusoidal current consumption and unitary power factor. It presents simulation results of the integration of EVs and PHEVs in terms of power quality, and experimental results of a smart charger which was specially developed for EV charging and that allows mitigation of the power quality degradation. Fundação para a Ciência e a Tecnologia (FCT)

NAS-wide simulation and passenger itinerary performance: Implications for NextGen benefits analysis

Scipedia content — Wed, 03 Feb 2021 17:21:59 +0100

NAS-wide simulations are one of the methods used to estimate annual system-wide benefits for Air Traffic Control modernization concepts-of-operations and technologies (e.g. NextGen/SESAR). These tools simulate the operation of up to 60,000 flights per day in various combinations of demand (i.e. flights) and capacity (i.e. airport and airspace capacity). The main input to the simulation is a schedule of flights (not a schedule of passenger itineraries). As a result, estimates of passenger delays assume all passengers are on direct itineraries only, and the impact of cancelled flights, missed connection, and airline network effects are not considered. This paper describes the results of an aggregate model of the operation of a hub-and-spoke network that takes into account passenger itineraries (i.e. direct and connecting) and a ll forms of itinerary disruptions (i.e. delayed flights, cancelled flights and missed connections). This model shows that the reduction in lost economic productivity generated from NAS-wide simulations is under-reported, as passenger trip delays due to delayed flights only account for approximately 40% of the total passenger trip delays. Furthermore, the model identifies the significant roles played by factors other than flight performance, such as airline itinerary structure, airline fleet mix (i.e. aircraft size), load factors and airline hub banking structure, on total passenger trip delay. For example, a 7–10% increase in load-factor can nullify the reduction in total passenger trip delay gained by a 5% improvement in on-time performance achieved by NextGen. The implications of these results on NextGen benefits assessments through NAS-wide simulation are discussed.

Prestressed Concrete Cylinder Pipe Condition Assessment—What Works, What Doesn't, What's Next

Scipedia content — Wed, 03 Feb 2021 17:21:38 +0100

This paper presents a summary of the research performed for Water Research Foundation on the evaluation of condition assessment and remaining service life prediction/failure margin analysis technologies in use for prestressed concrete cylinder pipe (PCCP). The project involved a literature review, an industry survey, and a workshop. The literature review integrated the published experiences with all condition assessment and monitoring technologies. The industry survey included design, distribution, and compilation of responses to a questionnaire sent to water utilities, technology stakeholders, and consultants to document their experiences. The workshop provided a venue to discuss utility experiences and utility needs. The results of the literature review, industry survey, and workshop were used to develop a Best Practices Guidance Manual that identifies a method of prioritizing pipelines for condition assessment; condition assessment, monitoring, and failure margin analysis technologies that are in existence or near deployment; benefits and limitations of existing technologies; gaps in knowledge; what works and what does not work in management of a pipeline; and further research and field work needed to improve condition assessment and pipeline management.

Mapping the Underworld: A Step-Change in the Approach to Utility Location and Designation

Scipedia content — Wed, 03 Feb 2021 17:15:54 +0100

Trenchless technologies (TT), unlike open cut trenching, offer the potential to install, maintain and refurbish buried utilities without the need to close long stretches of carriageway. Recent studies indicate that carbon emissions associated with trenchless installations are far smaller, and trenchless installations are more sustainable, than trenching. Yet utility companies, and their contractors, routinely shun trenchless technologies due to the perceived risk of damaging previously undetected third party assets. Mapping the Underworld (MTU) seeks to create a multi-sensor tool, and a new philosophical approach to underground mapping, to mitigate such risks and facilitate the routine adoption of TT. The novel approach is now being developed through the proof of concept stage towards field trials and the results of these proving trials form the basis of this paper. Moreover such street works, like all construction, repair, renewal and maintenance projects, must be reviewed in terms of a sustainability assessment framework to explore their real costs and benefits to the society on behalf of which, as ultimate ‘users’ of the facilities, the works are being carried out. This paper seeks to integrate the findings of a highly multi-disciplinary technology-based project with a wider research programme on the context of effective and efficient working in the streets. The lessons drawn from this programme of research extend to all aspects of pipeline engineering.

The use and understanding of the proximate status indication in traffic displays

Scipedia content — Wed, 03 Feb 2021 17:11:55 +0100

Traffic Collision Avoidance System (TCAS) traffic displays use symbol fill to distinguish “proximate” from “non-proximate” targets, where proximate targets are within a specified range and altitude of ownship, and non-proximate targets are outside these parameters. While this is satisfactory for TCAS displays, Cockpit Displays of Traffic Information (CDTI) can present much more information than TCAS displays, and an alternative use of symbol fill may be preferred. Since a symbol for traffic has a limited number of visual features for encoding information, CDTI symbology should only encode information that can be used effectively by pilots. This study evaluated the utility of the proximate status indication in an effort to understand whether it is useful enough to show on CDTIs. One hundred and one corporate and airline pilots were recruited for the web-based study via advertisements in on-line pilot newsletters. Pilots viewed videos of traffic scenarios depicted on a traffic display. Half the pilots were shown displays with a proximate status indication, and half the subjects were shown displays without a proximate status indication. Results showed that the proximate status indication did not improve consistency of pilot ratings relative to objective measures of threat and visibility. Furthermore, pilots who had the proximate status indication were 9% less accurate on average in selecting the highest threat traffic, whether the most threatening traffic was proximate or not. Pilots also answered questions about the proximate indication status in TCAS. Most pilots reported they found it useful, usually for prioritizing their attention. Most pilots recognized that a proximate symbol must be within a specific range and altitude, but nearly equal proportions of pilots also believed proximate traffic must always be a higher threat than non-proximate traffic, which is not the case. The combined results suggest that when assessing traffic threat, pilots place greater weight on U.S. Government work not protected by U.S. copyright the closeness of traffic than other key characteristics such as relative closing speed.

Using the Solution Space Diagram in Measuring the Effect of Sector Complexity During Merging Scenarios

Scipedia content — Wed, 03 Feb 2021 17:11:28 +0100

When designing Air Traffic Control (ATC) sectors and procedures, traffic complexity and workload are important issues. For predicting ATC workload, metrics based on the Solution Space Diagram (SSD) have been proposed. This paper studies the effect of sector design on workload and SSD metrics. When considering the SSD in evaluation of a sector, each aircraft within the sector introduces a zone of conflict, the Forbidden Beam Zone (FBZ), on the SSD. The properties of these FBZ are systematically studied to increase understanding of the SSD usability in assessing workload and sector complexity. The effects of sector design variables on Air Traffic Controller (ATCo) workload and also SSD properties were evaluated. Example of sector properties are, number of streams to be merged, the merge angle, the proximity of incoming aircraft and the variability of traffic mix of small and large aircraft. Based on the findings, each sector design variable leads to different effect on both workload and SSD properties. Apart from that, correlation between the workload and the SSD properties were found to be in a higher level than of the number of aircraft within the sector, proving that the SSD-based analysis to be a good workload indicator. These correlations were studied based on two different groups of subjects with ranging experience in order to demonstrate the robustness of the method.

Integration of a speed-dependent emission model in dynamic traffic assignment: a large scale application to the Paris metropolitan area

Scipedia content — Wed, 03 Feb 2021 16:58:40 +0100

International audience; It is a common practice, when interfacing a traffic assignment model with an average-speed emission model, to use link mean speeds instead of trip mean speeds. Using synthetic traffic data produced by a microscopic model, we show that both approaches do not capture well the effect of congestion on emissions. Instead, using the distributions of vehicle speeds - as opposed to a single average-speed value - can make an average-speed emission model behave consistently with a kinematic emission model. The main contribution of this paper is to show that simple, bimodal, speed distributions, can capture a significant part of the dynamic of congested traffic w.r.t. an average-speed emission model. (C) 2009 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the Organizing Committee.

Emergency response and traffic congestion: the dispatcher’s perspective

Scipedia content — Wed, 03 Feb 2021 16:48:36 +0100

Traffic congestion may impede the ability of emergency vehicles to reach the site of a traffic incident or other disaster in a fast and reliable manner. It is imperative that emergency dispatchers use real time traffic information in order to improve dispatching of Emergency Medical Services (EMS) to the disaster site. Preliminary research indicates, however, that many dispatchers have not been trained to cope with severe congestion nor have they been given the tools that would allow them to consider traffic congestion in the dispatching process. In order to (a) document the extend of this problem in the state of Alabama and (b) understand how traffic congestion impacts emergency dispatching decisions and response, this study developed and conducted a statewide survey of emergency dispatchers on behalf of the University Transportation Center at the University of Alabama at Birmingham. The survey sought feedback from EMS dispatchers in Alabama on current practices, positive and negative experiences, preferences, as well as their perceptions on the use of real time traffic data to help optimize emergency response and transport times. The results of the survey analysis clearly show that there is a disconnect between dispatching decisions and conditions in the field. Traffic congestion was generally not viewed as a major concern among the dispatchers surveyed nor was any real time traffic information used to improve decision making at the dispatching control center. Availability of real-time traffic information for dispatching purposes, and education of dispatchers about the opportunities and benefits that can be realized by using such information are very important steps toward improving Emergency Medical Services (EMS) performance and reliability, which in return can improve survivability of victims requiring medical attention.

A study of Wireless Sensor Network Architectures and Projects for Traffic Light Monitoring

Scipedia content — Wed, 03 Feb 2021 16:46:14 +0100

International audience; Vehicular traffic is increasing around the world, especially in urban areas. This increase results in a huge traffic congestion, which has dramatic consequences on economy, human health, and environment. Traditional methods used for traffic management, surveillance and control become inefficient in terms of performance, cost, maintenance, and support, with the increased traffic. Wireless Sensor Networks (WSN) is an emergent technology with an effective potential to overcome these difficulties, and will have a great added value to intelligent transportation systems (ITS). In this survey, we review traffic light projects and solutions. We discuss their architectural and engineering challenges, and shed some light on the future trends as well.

Document type: Conference object

Benefit Assessment of Precision Departure Release Capability Concept

Scipedia content — Wed, 03 Feb 2021 16:39:37 +0100

Precision Departure Release Capability concept is being evaluated by both the National Aeronautics and Space Administration and the Federal Aviation Administration as part of a larger goal of improving throughput, efficiency and capacity in integrated departure, arrival and surface operations. The concept is believed to have the potential of increasing flight efficiency and throughput by avoiding missing assigned slots and minimizing speed increase or path stretch to recover the slot. The main thrust of the paper is determining the impact of early and late departures from the departure runway when an aircraft has a slot assigned either at a meter fix or at the arrival airport. Results reported in the paper are for two scenarios. The first scenario considers flights out of Dallas/Fort Worth destined for Hartsfield-Jackson International Airport in Atlanta flying through the Meridian meter-fix in the Memphis Center with miles-in-trail constraints. The second scenario considers flights destined to George Bush Intercontinental/Houston Airport with specified airport arrival rate constraint. Results show that delay reduction can be achieved by allowing reasonable speed changes in scheduling. It was determined that the traffic volume between Dallas/Fort Worth and Atlanta via the Meridian fix is low and the departures times are spread enough that large departure schedule uncertainty can be tolerated. Flights can depart early or late within 90 minutes without accruing much more delay due to miles-in-trail constraint at the Meridian fix. In the Houston scenario, 808 arrivals from 174 airports were considered. Results show that delay experienced by the 16 Dallas/Fort Worth departures is higher if initial schedules of the remaining 792 flights are kept unaltered while they are rescheduled. Analysis shows that the probability of getting the initially assigned slot back after perturbation and rescheduling decreases with increasing standard deviation of the departure delay distributions. Results show that most Houston arrivals can be expected to be on time based on the assumed zero-mean Normal departure delay distributions achievable by Precision Departure Release Capability. In the current system, airport-departure delay, which is the sum of gate-departure delay and taxi-out delay, is observed at the airports. This delay acts as a bias, which can be reduced by Precision Departure Release Capability.

Detection and recognition of urban road markings using images

Scipedia content — Wed, 03 Feb 2021 16:36:05 +0100

While road lane markings detection was extensively studied, in particular for intelligent vehicle applications, the detection and recognition of all kind of marking such as arrows, crosswalks, zebras, words, pictograms, continuous and discontinuous lane markings was drastically less studied. However, it has many potential applications in the design of advanced driver assistance systems, as well as for asset management along itineraries. An algorithm is proposed which is based on the following processing steps: marking pixel extraction, detection using connected components before Inverse Perspective Mapping and recognition based on the comparison with a single pattern or with repetitive rectangular patterns. The proposed algorithm is able to detect and recognize repetitive markings (such as crosswalks) as well as single patterns (such as arrows). We believe that the proposed algorithm can be extended easily to solve the problem of the identification of all types of markings.

On the Behavior of a Stuck Curved Pipe-Jacking

Scipedia content — Wed, 03 Feb 2021 16:17:09 +0100

The influences of coefficient of friction (COF) and contact condition on the soil-pipe interaction have been analyzed and discussed by different related studies. However, the assessments of various jacking forces in literatures rarely explore the impact of changes in the COF caused by alterations in the geological conditions or construction situations. This paper investigated common construction problems in two curved pipejacking cases from Chiayi and Kaohsiung, and one case of straight, long-distance pipejacking in Taichung. We discovered that the actual jacking force often exceeded the pre-construction calculations. To examine the impact of a stuck pipe on the jacking force, this study sets different contact properties between the soil and the pipe within the area of the stuck pipe. Finite element method was used to simulate a horizontal curved pipejacking with a stuck condition. In the stuck pipe simulation, we found that because of the intense interactions between the pipe and the soil, the distribution of stress increased, and the jacking force also increased along with an increase in the area of stuck pipe.

Human-in-the-Loop Simulation of Three-Dimensional Path Arrival Management with Trajectory Error

Scipedia content — Wed, 03 Feb 2021 16:15:38 +0100

The Efficient Descent Advisor (EDA) is a prototype ground-based decision support tool (DST) that assists air traffic controllers in efficiently managing arrivals in en route airspace. Currently under development at NASA Ames Research Center, EDA is an extension of the Traffic Management Advisor (TMA) and a component of the Three Dimensional Path Arrival Management (3D PAM) project, a collaborative FAA/NASA/Industry effort. The objective of this study was twofold: one was to investigate the effects of fixed or dynamic turn-out points as part of the path stretch maneuver on EDA operation performance and controller workload. The other was to examine the feasibility of the 3D PAM concept under the presence of uncertainty in aircraft weight, winds, and pilot maneuver conformance. Results indicate that the dynamic start-point configuration caused more corrective advisories to be issued, and made the traffic patterns more complex, though the configuration had little impact on controller workload. Results also demonstrated that the inclusion of uncertainties of the chosen magnitude did not significantly impact either EDA functions or usability for the traffic simulated.

Electric vehicles in urban areas: test cases using a scenario simulator

Scipedia content — Wed, 03 Feb 2021 16:10:19 +0100

Electric vehicles introduction will affect cities environment and urban mobility policies. Network system operators will have to consider the electric vehicles in planning and operation activities due to electric vehicles’ dependency on the electricity grid. The present paper presents test cases using an Electric Vehicle Scenario Simulator (EVeSSi) being developed by the authors. The test cases include two scenarios considering a 33 bus network with up to 2000 electric vehicles in the urban area. The scenarios consider a penetration of 10% of electric vehicles (200 of 2000), 30% (600) and 100% (2000). The first scenario will evaluate network impacts and the second scenario will evaluate CO2 emissions and fuel consumption.

Modeling and Simulation Vehicle Air Brake System

Scipedia content — Wed, 03 Feb 2021 16:09:40 +0100

brake system has been widely used in heavy trucks and intercity buses for its great superiority over other brake system. The practical performance of air brake system may be greatly different from if we analyze it with static theory. Thus, it is necessary to build an integrate air brake system model to simulate the process of brake accurately. However, the dynamic mathematic model of air brake system is very complicate, which makes the model hard to be solved. In this paper, the components of air brake system are decomposed to several basic standard pneumatic components, and then build the system based on these basic standard pneumatic components. The standard pneumatic components which are built in the softwareMWorks based on Modelica language include cylinder, nozzle, air reservoir, volume, and air pipe. An air brake system which contains brake valve, relay valve, brake chambers and pipelines is made based on the standard pneumatic components. The simulation results show the dynamic characteristics of air brake system.

Building a generic debugger for information extraction pipelines

Scipedia content — Wed, 03 Feb 2021 16:08:32 +0100

Complex information extraction (IE) pipelines are becoming an integral component of most text processing frameworks. We introduce a first system to help IE users analyze extraction pipeline semantics and operator transformations interactively while debugging. This allows the effort to be proportional to the need, and to focus on the portions of the pipeline under the greatest suspicion. We present a generic debugger for running post-execution analysis of any IE pipeline consisting of arbitrary types of operators. For this, we propose an effective provenance model for IE pipelines which captures a variety of operator types, ranging from those for which full to no specifications are available. We have evaluated our proposed algorithms and provenance model on large-scale real-world extraction pipelines.

Decision Making Regarding Aircraft De-Icing and In-Flight Icing Using the Canadian Airport Nowcasting System (CAN-Now)

Scipedia content — Wed, 03 Feb 2021 16:06:57 +0100

The Canadian Airport Nowcasting Project (CAN-Now) has developed an advanced prototype all-season weather forecasting and nowcasting system that can be used at major airports. This system uses numerical model data, pilot reports, ground in-situ sensor observations (precipitation, icing, ceiling, visibility, winds, etc), on-site remote sensing (such as vertically pointing radar and microwave radiometer) and off-site remote sensing (satellite and radar) information to provide detailed nowcasts out to approximately 6 hours. The nowcasts, or short term weather forecasts, should allow decision makers at airports such as pilots, dispatchers, deicing crews, ground personnel or air traffic controllers to make plans with increased margins of safety and improved efficiency. The system is being developed and tested at Toronto Pearson International Airport (CYYZ) and Vancouver International Airport (CYVR). A Situation Chart has been developed to allow users to have a high glance value product which identifies significant weather related problems at the airport. Some new products combining observations and numerical model output into nowcasts are being tested. This talk will describe the uses of the system for decisions regarding aircraft de-icing at the ground and in-flight icing over the airport. Some statistical verifications of forecast products regarding precipitation amount, precipitation type, in-flight icing, etc, will be given.

Impact of Tactical and Strategic Weather Avoidance on Separation Assurance

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

The ability to keep flights away from weather hazards while maintaining aircraft-to- aircraft separation is critically important. The Advanced Airspace Concept is an automation concept that implements a ground-based strategic conflict resolution algorithm for management of aircraft separation. The impact of dynamic and uncertain weather avoidance on this concept is investigated. A strategic weather rerouting system is integrated with the Advanced Airspace Concept, which also provides a tactical weather avoidance algorithm, in a fast time simulation of the Air Transportation System. Strategic weather rerouting is used to plan routes around weather in the 20 minute to two-hour time horizon. To address forecast uncertainty, flight routes are revised at 15 minute intervals. Tactical weather avoidance is used for short term trajectory adjustments (30 minute planning horizon) that are updated every minute to address any weather conflicts (instances where aircraft are predicted to pass through weather cells) that are left unresolved by strategic weather rerouting. The fast time simulation is used to assess the impact of tactical weather avoidance on the performance of automated conflict resolution as well as the impact of strategic weather rerouting on both conflict resolution and tactical weather avoidance. The results demonstrate that both tactical weather avoidance and strategic weather rerouting increase the algorithm complexity required to find aircraft conflict resolutions. Results also demonstrate that tactical weather avoidance is prone to higher airborne delay than strategic weather rerouting. Adding strategic weather rerouting to tactical weather avoidance reduces total airborne delays for the reported scenario by 18% and reduces the number of remaining weather violations by 13%. Finally, two features are identified that have proven important for strategic weather rerouting to realize these benefits; namely, the ability to revise reroutes and the use of maneuvers that start far ahead of encountering a weather cell when rerouting around weather.

Comparing Data from Mobile and Static Traffic Sensors for Travel Time Assessment

Scipedia content — Wed, 03 Feb 2021 15:42:05 +0100

Travel time and speed measures on road networks provide key information to identify critical spots of congestion and evaluate the scale of this phenomenon across an urban area. Many technologies are currently available to measure travel time and speed, but each has its limitations. As part of a wider project aiming to develop travel time reliability indicators, this paper presents a comparison and validation of data collected through four different non-intrusive techniques: floating cars, GPS traces, Bluetooth detections and video processing. First, some background information regarding the project and the modeling of travel times and speed on highway networks is provided. Then, a comparison between the various sources of data is presented. Finally, the characteristics of the various data sources are discussed based on the relevance and the availability of the sources.

Knowledge-aided multisensor data fusion for maritime surveillance

Scipedia content — Wed, 03 Feb 2021 15:36:53 +0100

Multi sensor fusion techniques are widely employed in several surveillance applications (e.g., battlefield monitoring, air traffic control, camp protection, etc). The necessity of tracking the elements of a dynamic system usually requires combining information from heterogeneous data sources in order to overcome the limitations of each sensor. The gathered information might be related to the target kinematics (position, velocity), its physical features (shape, size, composition) or intentions (route plan, friend/foe, engaged sensor modes, etc). The combination of such heterogeneous sensor data proved to benefit from the exploitation of context information, i.e., static and dynamic features of the scenario, represented in a Knowledge Base (KB). A Geographic Information System (GIS) is a typical example for a KB that can be exploited for the enhancement of multi sensor data fusion. The present paper describes potential strategies for "knowledge-based" data fusion in the area of Maritime Situational Awareness (MSA). MSA is founded on the data from heterogeneous sources, including radars, Navigation Aids, air- and space-based monitoring services, and recently-conceived passive sensors. Several strategies for optimally fusing two or more of these information data flows have been proposed for MSA applications. Relevant KB information comprises port locations, coastal lines, preferred routes, traffic rules, and potentially a maritime vessel database. We propose mathematical models and techniques to integrate kinematic constraints, e.g., in terms of navigation fields, and different object behaviour into a data fusion approach. For an exemplary sensor suite, we evaluate performance measures in the framework of centralised and decentralised fusion architectures.

Technical and economic feasibility of the use of airships within two Portuguese market niches: the tourism and the urban logistic case studies

Scipedia content — Wed, 03 Feb 2021 15:36:20 +0100

over the world there are several countries where airships are being used for military and civilian purposes. The rebirth of this mean of transportation, capable of easily overcoming some deficiencies of the conventional ones, brings medium and long term economic benefits. In addition, they offer different services at lower costs, and they also may stimulate new commercial and industrial activities and even new transactional routes. The background of airship technology comes from the XVIII century. Since then, all those years were of scientific and empirical knowledge. Now, they form the basis for a sustainable future in emerging technologies, making the return of airships possible. This revived interest in airship technology brings a multitude of technical concepts resulting from interdisciplinary research. Consequently, the state of art of airships presents new research which paves the way for the reappearance of renewed horizons with regards to the use of airships. Companies are focused on the research, development and testing of new airship concepts and designs too. Nowadays, airships are being studied for commercial transport in different parts of the globe, from Canada, Brazil, Peru, to Australia. India, for example, has studies about the connection to remote areas with poor surface infrastructure which only can be reached by air or walking. This way, it's expected that airships will become a competitive mean of transport to link areas served by deficient transport infrastructures. Taking the principles of sustainable development of air transport, airships are the most environment-friendly vehicles with lower fuel consumption and with higher endurance. Therefore, as a result, they are paving the way for new markets. This work examines these technological improvements and the economic feasibility of the use of airships in certain market niches. Mainly, this work makes use of a study concerning the viability of the use of airships within Portuguese Tourism and Urban Logistic activity sectors. This paper is organized as follows: firstly, state of the art reviews about airships technological characteristics: operational constraints, operation scenarios, and international and national legislation. Secondly, improvement of two case studies within the Portuguese territory (touristic flights and urban logistic activity): operational parameters evaluation and operating cost estimation. And thirdly, some insights and challenges of research that is still in progress.

Logistique urbaine et épicerie électronique : les livraisons de proximité ont-elles un impact positif sur les parcours d'achat des ménages ?

Scipedia content — Wed, 03 Feb 2021 15:34:16 +0100

International audience; This paper proposes a discussion of three scenarios related to e-grocery distribution developments, in order to identify and analyze the impacts of new forms of proximity deliveries on households' shopping trip flows. Firstly, we present the two basic logistics models adopted by online retailers (in-warehouse picking and in-store picking), as well as the three main proximity delivery approaches in e-grocery. Secondly, we focus on city logistics, more particularly on the relations between e-grocery development and the related various urban goods movement flows. Thirdly, we propose to study the impact of these systems on consumer's purchasing trips and, to this end, we use an empirical simulation approach in order to make a comparison of these three scenarios.

Document type: Article

Variable speed limits for green mobility

Scipedia content — Wed, 03 Feb 2021 15:31:55 +0100

Due to increasing environmental concerns the focus of traffic management and control is shifting towards optimizing the traffic control measures to also reduce traffic emissions and fuel consumption. In this context we propose a model-based predictive traffic control approach for the balanced reduction of travel times, emissions, and fuel consumption for freeway networks, where not only the local emissions are taken into account but also the dispersion of the emissions to various target zones near the freeways. The core of the approach is a new efficient model for describing the area-wide dispersion of the emissions that is much faster than the models we have proposed in earlier papers. We present a detailed description of the new so-called expanding grid-based model and we embed it in a model-based predictive traffic control approach using variable speed limits.

An agent model for the simulation of electrical vehicle charging management

Scipedia content — Wed, 03 Feb 2021 15:28:35 +0100

This paper presents an agent model to the simulation of the charging process to control and monitor the Electric Vehicle charging process, taking into account the existing power distribution limitations. The process is based on the simulation study of the user consumption profile, based on two main steps: in the first step is performed the home consumption simulation by the data collection and the analysis of consumption of three family types (small, medium and large) and in the second step is the Electric Vehicle integration, using the identified profiles in low voltage. In this simulation we evaluate the limitations of the existing electrical power grid, and the factors that influence the EV charging. The main results obtained are the typical charging curves for residential consumption, which identify the power available for the Electric Vehicle charging, and determine the capability of the actual electrical power grid to supply energy to the final consumers and to charge the bank of batteries of the Electrical Vehicles, which can occur simultaneously. Fundação para a Ciência e a Tecnologia (FCT)

Impacts of Intermediate Cruise-Altitude Advisory for Conflict-Free Continuous-Descent Arrival

Scipedia content — Tue, 02 Feb 2021 08:45:45 +0100

Efficient Descent Advisor (EDA) is a proposed ground-based decision-support tool for Air Route Traffic Control Center (ARTCC) sector controllers for managing arrival flows. It calculates the maneuver instructions for an arrival flight to fly a conflict-free (when able), fuel-efficient, continuous-descent trajectory and also meet a time-based metering requirement at the Terminal Radar Approach Control (TRACON) boundary. Currently, speed variations and path-stretch maneuvers are the only degrees of freedom used by EDA to find a solution. This study examined the feasibility of altitude change as an additional degree of freedom. Results of the human-in-the-loop simulation experiment showed that the altitude-advisory capability reduced the number of conflicting EDA advisories. It also reduced controller workload when the traffic situation was complex. Results also suggested that changes to EDA's user interface design and inter-sector coordination procedures are required for controllers to accept an altitude-advisory capability.

Assessing speed enforcement policy measures by analyzing multi sustainability criteria

Scipedia content — Tue, 02 Feb 2021 08:39:12 +0100

This paper discusses how the sustainability assessment is generally used to identify the unsustainable effects of policy measures, such as sustainable transport policy strategies. Still, sustainability effects of road traffic safety policy measures are insufficiently studied. This paper assesses the sustainability of speed enforcement policy measures on highways. A multicriteria evaluation framework, containing social, economic and environmental assessment criteria, evaluates different speed enforcement policy alternatives. The framework determines how the policy alternatives meet the criteria and ranks the policy alternatives according to their sustainability. The results presented in this paper show that intelligent speed enforcement strategies are more sustainable than automatic and manned speed enforcement strategies. Multicriteria have proved to be very useful for assessing sustainability.

Statistical Analysis of Condition Assessment Data and Prediction of Future Performance of PCCP

Scipedia content — Tue, 02 Feb 2021 08:39:01 +0100

This paper presents the benefits of a well-managed, long-term asset management program in determining the current condition and predicting future deterioration of prestressed concrete cylinder pipe (PCCP). More than 10 years of inspection and monitoring data were analyzed, accumulated from Palo Verde Nuclear Generating Station (PVNGS), operated by the Arizona Public Service Company (APS). Pipe segments were inspected every 3 years on average. These data were analyzed to determine the current condition of the PCCP assets, and to develop statistical models of future deterioration of the pipeline and future deterioration rates of distressed pipes in different repair priorities by tracking individual deterioration zones throughout the inspection history. Using established risk and uncertainty analysis techniques, future repair priorities are forecast. The frequency of inspections and quality of the data collected allowed us to develop meaningful predictive statistical models of deterioration in PCCP assets. Starting from the detailed data on distress levels in the pipelines, the models forecast future progression of distress, including the total number of distressed pipes, total number of highly distressed pipes requiring repair or replacement, areas of severe distress, areas of rapid deterioration, and specific pipe segments reaching severe distress level in a specific future time period. The inspection data and results of this study were incorporated into a Geographic Information System (GIS). Such information is of paramount importance for effective PCCP asset management.

Inclusion of the aviation sector into the emission trading scheme : an economic analysis

Scipedia content — Tue, 02 Feb 2021 08:22:16 +0100

International audience; The air transport sector is going to enter the European Trading Scheme in 2012. The regulation of CO2 emissions is costly for airlines and modifies the organization of their market. Our paper proposes an economic analysis in which the regulation but also CO2 emissions of airlines are modelled. We show that, in a perfect competition setting, the difference between passengers carried without regulation and when the regulation is considered is negative for the best-performing planes. However, for the less efficient aircraft, the implementation of the regulation entails a reduction of airlines activity, and therefore a low level of carbon emissions.

A hierarchical approach for dynamic origin-destination matrix estimation on large-scale congested networks

Scipedia content — Tue, 02 Feb 2021 08:09:39 +0100

In this paper we propose a hierarchical approach for decomposing and simplifying the dynamic OD estimation procedure for large-scale congested networks. The main idea is to subdivide the network into multiple hierarchical levels. Next an OD estimation is performed on each level separately, starting with the highest level, and the output of this estimation is used as input for the OD estimation on a lower level. The main advantage of this approach is that different levels of complexity (of the DNL/DTA model and of the estimation method) can be used for different parts of the network as required. In addition, this hierarchical approach solves many practical and theoretical limitations of traditional OD estimation methods, which have been identified in previous research. ispartof: pages:1543-1548 ispartof: 2011 14TH INTERNATIONAL IEEE CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC) pages:1543-1548 ispartof: IEEE ITSC 2011 location:Washington DC date:5 Oct - 7 Oct 2011 status: published

How to measure monitoring performance of pilots and air traffic controllers

Scipedia content — Tue, 02 Feb 2021 08:04:19 +0100

In prior research on the future of aviation it was established that operators will have to work with highly automated systems. Increasing automation will require operators monitoring appropriately (OMA). OMA are expected to demonstrate the use of distinctly different monitoring phases (orientation, anticipation, detection, and recheck). Within these phases, they must grasp in time the relevant information that would enable them to take control should automation fail. The presented study aims at finding appropriate measurements for the identification of OMA on the basis of eye tracking. In order to do this, a normative model of adequate monitoring behavior was designed including the definition of areas of interest. We tested 90 participants who had to monitor a dynamic automatic process, and then take control. In order to decide on suitable eye tracking parameters it was asked which parameters are significantly related to manual control performance. The results show that the suitability of parameters depends on the specific phase of the monitoring process. Gaze durations allow for differentiating between high and low performing subjects during orientation phases. In contrast, relative fixation counts are suitable for predicting monitoring performance during detection phases. In general, the results support the assumption that eye tracking parameters are appropriate for identifying OMA.

Calibration of Fitting Loss Coefficients for Modelling Purpose of a Plastic Pipeline

Scipedia content — Tue, 02 Feb 2021 07:59:29 +0100

International audience; Motivated by the sensitivity of model-based monitor- ing algorithms to the so-called Equivalent Straight Length (ESL) of a pipeline, this paper proposes an experiment- based calibration of this parameter and also for the val- ues of the Fitting Loss Coefficients (FLC). This comes as an alternative to achieve a better description of the real flow behavior in a pipeline than the modelling obtained by using the FLC from the manufacturer data-sheet. The proposed calibration method relies on a flow mod- elling, and Kalman observer-based estimation of the FLC of a pipeline. The friction coefficient in the model is es- timated by the explicit so-called Swamee-Jain equation. The approach only assumes sensors of flow and pressure at the ends of the duct. Experimental results are presented

Classification of traffic video based on a spatiotemporal orientation analysis

Scipedia content — Tue, 02 Feb 2021 07:58:24 +0100

This paper describes a system for classifying traffic congestion videos based on their observed visual dynamics. Central to the proposed system is treating traffic flow identification as an instance of dynamic texture classification. More specifically, a recent discriminative model of dynamic textures is adapted for the special case of traffic flows. This approach avoids the need for segmentation, tracking and motion estimation that typify extant approaches. Classification is based on matching distributions (or histograms) of spacetime orientation structure. Empirical evaluation on a publicly available data set shows high classification performance and robustness to typical environmental conditions (e.g., variable lighting).

Reputation for Vertical Handover decision making

Scipedia content — Tue, 02 Feb 2021 07:54:18 +0100

International audience; To meet the continuously increasing demands and requirements of mobile users, next generation wireless systems are more and more relaying on the coexistence of heterogeneous wireless networks. The objective is to provide any time and anywhere connectivity to users. One of the main challenges in such a heterogeneous environment is mobility management, including network selection and Vertical Handover (VHO) procedures. In this paper, we propose a VHO management solution combining the use of reputation as a Quality of Experience (QoE) indicator for fast decision-making and the Stream Control Transmission Protocol (SCTP) as a mobility protocol. This reputation-based Vertical Handover solution operates on the previous observed experiences of users within the different available networks to make fast decisions and uses the SCTP protocol that provides multihoming facilities. Performance results demonstrate that the proposed handover scheme provides seamless mobility, with low latency, good throughput and almost no packet lo

Dynamic lane reversal in traffic management

Scipedia content — Tue, 02 Feb 2021 07:47:08 +0100

Contraflow lane reversal — the reversal of lanes in order to temporarily increase the capacity of congested roads — can effectively mitigate traffic congestion during rush hour and emergency evacuation. However, contraflow lane reversal deployed in several cities are designed for specific traffic patterns at specific hours, and do not adapt to fluctuations in actual traffic. Motivated by recent advances in autonomous vehicle technology, we propose a framework for dynamic lane reversal in which the lane directionality is updated quickly and automatically in response to instantaneous traffic conditions recorded by traffic sensors. We analyze the conditions under which dynamic lane reversal is effective and propose an integer linear programming formulation and a bi-level programming formulation to compute the optimal lane reversal configuration that maximizes the traffic flow. In our experiments, active contraflow increases network efficiency by 72%.

Reducing congestion through persuasive gaming

Scipedia content — Tue, 02 Feb 2021 07:23:19 +0100

In this paper we provide an overview of the I-GEAR (incentives and gaming environments for automobile routing) project that is intended to reduce traffic congestion in Luxembourg through the use of persuasive gaming. In order to illustrate some of the issues involved we also present an outline concept of a live game in which we propose to encourage the workshop participants to take part. If a sufficient number of workshop participants take part, this real life game could even be used as a small scale study within the project.

Fusion of laserscannner and video based lanemarking detection for robust lateral vehicle control and lane change maneuvers

Scipedia content — Tue, 02 Feb 2021 07:22:03 +0100

The knowledge about lanes and the exact position on the road is fundamental for many advanced driver assistance systems. In this paper, a novel iterative histogram based approach with occupancy grids for the detection of multiple lanes is proposed. In highway scenarios, our approach is highly suitable to determine the correct number of all existing lanes on the road. Additionally, the output of the laserscannner based lane detection is fused with a production-available vision based system. It is shown that both sensor systems perfectly complement each other to increase the robustness of a lane tracking system. The achieved accuracy of the fusion system, the laserscannner and video based system is evaluated with a highly accurate DGPS to investigate the performance with respect to lateral vehicle control applications.

Evaluation of High Density Air Traffic Operations with Automation for Separation Assurance, Weather Avoidance and Schedule Conformance

Scipedia content — Tue, 02 Feb 2021 07:13:48 +0100

In this paper we discuss the development and evaluation of our prototype technologies and procedures for far-term air traffic control operations with automation for separation assurance, weather avoidance and schedule conformance. Controller-in-the-loop simulations in the Airspace Operations Laboratory at the NASA Ames Research Center in 2010 have shown very promising results. We found the operations to provide high airspace throughput, excellent efficiency and schedule conformance. The simulation also highlighted areas for improvements: Short-term conflict situations sometimes resulted in separation violations, particularly for transitioning aircraft in complex traffic flows. The combination of heavy metering and growing weather resulted in an increased number of aircraft penetrating convective weather cells. To address these shortcomings technologies and procedures have been improved and the operations are being re-evaluated with the same scenarios. In this paper we will first describe the concept and technologies for automating separation assurance, weather avoidance, and schedule conformance. Second, the results from the 2010 simulation will be reviewed. We report human-systems integration aspects, safety and efficiency results as well as airspace throughput, workload, and operational acceptability. Next, improvements will be discussed that were made to address identified shortcomings. We conclude that, with further refinements, air traffic control operations with ground-based automated separation assurance can routinely provide currently unachievable levels of traffic throughput in the en route airspace.

A new teletraffic approach for network planning and evolution prediction

Scipedia content — Tue, 02 Feb 2021 07:09:19 +0100

This paper outlines a new multi-layer optimization approach that considers stochastic traffic composed of heavy tailed flows for optimizing traffic engineering and grooming, network design, dimensioning and planning, and evolution prediction.

Virtual Integration Platforms (VIP) –A Concept for Integrated and Interdisciplinary Air Transportation Research and Assessment

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

This paper introduces the concept of Virtual Integration Platforms (VIP) as a method for the development, integration and assessment of new Air Transportation System (ATS) concepts. The VIP concept aims to enable a meaningful integration and assessment of new technologies on a system-of-systems scale. The approach taken follows a systems engineering-based approach to develop new ATS concepts. We describe three VIPs, each of them focussing on a different market segment: One VIP considers short-to-medium haul air transport, one VIP focusses on long haul transport and one VIP studies new business travel concepts. The scope of a virtual integration platform is based on operational targets for various time horizons. Four main substructures of the air transportation system were identified: aircraft, airport, ATM and airline. This paper also includes two examples to demonstrate the VIP concept and its application.

Costs and benefits of logistics pooling for urban freight distribution: scenario simulation and assessment for strategic decision support

Scipedia content — Tue, 02 Feb 2021 06:38:16 +0100

International audience; Collaborative transportation and logistics pooling are relatively new concepts in research, but are very popular in practice. In the last years, collaborative transportation seems a good city logistics alternative to classical urban consolidation centres, but it is still in a development stage. This paper proposes a framework for urban logistics pooling ex-ante evaluation. This framework is developed with two purposes. The first is to generate comparable contrasted or progressive scenarios representing realistic situations; the second to simulate and assess them to make a "before-after" comparative analysis. In this framework, a demand generation model is combined with a route optimization algorithm to simulate the resulting routes of the proposed individual or collaborative distribution schemes assumed by each scenario. Then, several indicators can be obtained, mainly travelled distances, working times, road occupancy rates and operational monetary costs. To illustrate that framework, several scenarios for the urban area of Lyon (France) are simulated and discussed to illustrate the proposed framework possible applications.

Highly automated driving on highways: system implementation on PC and automotive ECUs

Scipedia content — Tue, 02 Feb 2021 06:31:55 +0100

ITSC 2011 : International IEEE Conference on Intelligent Transportation Systems, WASHINGTON, ETATS-UNIS, 05-/10/2011 - 07/10/2011; This paper presents the implementation of a highly automated driving system on automotive Electronic Control Units (ECUs). It integrates a perception component, which uses the combination of high-level sensors to map the environment, a co-pilot, which finds an optimal trajectory in this environment and a control component, which guides the vehicle on this trajectory. The cooperation between human and automation is managed by the driving Mode Selection and arbitration Unit (MSU) and Human-Machine Interface (HMI) components. The co-pilot and control components have been implemented on AUTOSAR-based ECUs, the other components in the RTMaps environment on a standard PC. It has been first been tested on the simulation tool SiVIC and was then transferred to a physical vehicle on test track.

Transitioning from Leak Detection to Leak Prevention: Proactive Repair of Steel Pipelines Using Fiber Reinforced Polymer (FRP) Composites

Scipedia content — Tue, 02 Feb 2021 06:12:22 +0100

Steel pipelines are the one of the most economic and safe transport systems for water, and are often our population centers' only means of receiving goods which are vital to day-to-day existence. As a means of long-distance transport, pipelines have to fulfill high demands of safety, and reliability. Most metallic pipelines, regardless of what they transport, are designed with a typical life span of 25 – 50 years. When they begin to fail, the pipelines slowly form leaks at construction joints, corroded areas and small structural cracks. These leaks can gradually progress to a catastrophic failure if gone undetected or can result in substantial water loss over extended periods of time. Pipeline leak detection systems (LDS) are beneficial because they can enhance productivity and system reliability by means of reduced downtime and reduced inspection time through pinpointing and localizing the leak locations. LDS Systems are therefore an important aspect of pipeline technology that are primarily used to assist Pipeline Owners in detecting leaks. But what happens after leaks have been detected in steel pipelines and require immediate repair? This paper will present the importance of the correlation between efficient leak detection and pipeline repair. The general guidelines for the proper design and installation of fiber wrap strengthening systems for steel pipelines will also be presented. Discussion will center upon case histories and best practices to avoid over or under-designing the retrofit, and how to best implement the proper installation of these CFRP systems. The case studies will be explored in detail to evaluate the performance of past and present designs, both for municipal and industrial clients.

Design of pipelines for high operating pressure by numerical simulations and experimental validation

Scipedia content — Tue, 02 Feb 2021 05:59:54 +0100

For pipelines laid in difficult ground, as frequently encountered in Alpine regions, a pipe system, consisting of individual pipes, made of ductile cast iron, which are connected at joints at the construction site, are a favourable type of construction. The paper deals with the development of such pipelines for high operating pressures. Because the joints have to sustain both the high operating pressure and high axial forces assuring water tightness, they are a critical part of such pipelines. In this contribution the synthesis of numerical simulations and experimental validation will be presented as an efficient approach for developing such pipes. The dimensions of prototypes are determined on the basis of the results of fully three-dimensional FE-simulations. These prototypes are then used to check the design by ultimate load testes and to compare the numerical prediction with the measured response.