Scipedia: Documents published in 2014

In‐service life estimation of damaged gas pipelines : Full‐scale experiments and finite element analyses

Scipedia content — Mon, 01 Feb 2021 16:15:14 +0100

International audience; Statistical analysis reveals that mechanical damage is the first cause of incidents on gas transmission pipelines. They can be created by third party activities such as excavator tooth impact or by interaction between the pipe and rocks. To manage the damaged pipeline safely without useless cost, there is a need to investigate the mechanical behaviour of dented pipelines under a varying internal pressure. The purpose of this study is to characterize the stress and strain field around defects in pipes submitted to cyclic pressure loadings in order to estimate their residual lifetime. Full 3D finite element analyses of the denting process followed by cyclic loading are performed. Full-scale experiments on dented sections are planned.

Arbitration for balancing control between the driver and ADAS systems in an automated vehicle: Survey and approach

Scipedia content — Mon, 01 Feb 2021 15:55:05 +0100

International audience; — Automated functions for real scenarios have been increasing in last years in the automotive industry. Many research contributions have been done in this field. However, other problems have come to the drivers: When should they (the drivers or the new automated systems) be able to take control of the vehicle? This question has not a simple answer; it de-pends on different conditions, such as: the environment, driver condition, vehicle capabilities, fault tolerance, among others. For this reason, in this work we will analyze the acceptability to the ADAS functions available in the market, and its relation with the different control actions. In this paper a survey on arbitration and control solutions in ADAS is presented. It will allow to create the basis for future development of a generic ADAS control (the lateral and longitudinal behavior), based on the integration of the application request, the driver behavior and driving conditions in the framework of the DESERVE project (DEvelopment platform for Safe and Efficient dRiVE 1 , a ARTEMIS project 2012-2105). The main aim of this work is to allow the development of a new generation of ADAS solutions where the control could be effectively shared between the vehicle and the driver. Different solutions of shared control have been analyzed. A first approach is proposed, based on the presented solutions.

Impact of Small-Scale Reeling Simulation on Mechanical Properties on Line Pipe Steel

Scipedia content — Mon, 01 Feb 2021 15:54:03 +0100

Reel-laying is a fast and cost effective method to install pipelines since the time consuming operations of welding and inspection are conducted onshore. During reel-laying repeated plastic strain is introduced into a pipeline which may affect strength and ductility of the line pipe material. Based on the experience, it has been shown that the small-scale reeling test procedure according to DNV-OS-F101 [1] is a good way to inspect the mechanical properties for the reel-laying process. Coupons from pipes are loaded in tension and compression tests and aged if required. Specimens for mechanical testing are machined from these coupons and tested according to the corresponding standards."/jats:p" "jats:p"This paper demonstrates current efforts to demonstrate the usability of cold-formed HFI pipes from Salzgitter Mannesmann Line Pipe GmbH (MLP) for the reel-laying process. In a first step the results of the pre-strained materials are compared in extensive material tests with the undeformed incoming materials. The effect of thermal aging from the coating process on the reeling behavior is then examined, in relation to the background of thermal aging. In discussing the difference between compression and tension zone of the reeled pipe, the influence according to the load conditions is analyzed by the material property tests. This paper demonstrates current efforts of the availability for use of cold-formed HFI pipes for the real-laying process. In addition, the report notes the difference and the effects of the material properties to testing according to the strain-based or stress-based load conditions. In discussing the influence of the tempered conditions of the mechanical properties, therefore two different pipe conditions are investigated by the small scale-reeling (SSR) testing procedure. In summary the results of the pre-strain materials are comparable with the unformed incoming materials.

Monitoring Flexible Gas Pipeline with a Microphone and Artificial Neural Networks

Scipedia content — Mon, 01 Feb 2021 15:53:46 +0100

Pipeline networks are complex systems of ducts transporting gas and chemical products through long distances. With the purpose to track these leaks a technique, based on the analysis of sound noises ca ptured by a microphone and on pressure transients generate d by leak occurrence, was developed. Neural Artificial Networks were applied to determine leak magnitude and leak location. The experimental results showed that it is possible to detect leaks in pipelines. The dynamics of these noises in time were used as input to the neur al model to determine the location and magnitude of th e leaks.

Impact analysis of urban structure and the economic sustainability of public transport in the city of Murcia (Spain)

Scipedia content — Mon, 01 Feb 2021 15:53:31 +0100

One of the fundamentals of an efficient public transport system is economic sustainability. The poorly structured growth of cities sometimes leads to the difficulty to maintain urban transport systems for public administrations. An interesting example of this territorial problem in urban and intercity transportation is the city of Murcia, the capital of a municipality of nearly 900 km2 equipped with various multi-modal public transport networks. This city of over 400,000 inhabitants has a historically dispersed urban structure where the population spread has been aggravated in recent years by a strong urban growth. The accelerated development of the city, coupled with the current crisis and budgetary consolidation, has made some public systems of urban and intercity transport economically unsustainable. This article analyzes the impact that the urban development of the city of Murcia has had on the various systems of urban and intercity transportation: car, bus, tram, suburban, etc. A diagnosis of the current problems and possible solutions for the future will be presented in order to stimulate an economically sustainable public transport strategy.

New Advances in Post-Installed Subsea Monitoring Systems for Structural and Flow Assurance Evaluation

Scipedia content — Mon, 01 Feb 2021 15:52:14 +0100

An overview of fiber optic sensors for temperature, pressure, strain, and fatigue of subsea structures is provided. Current progress details efforts to ensure proper installation and bonding to existing risers, flow-lines, mooring lines, trees, and other structures in actual subsea environments. Developments include clamp prototypes, bonding techniques, long-term fatigue analysis, sensor calibration, and temperature compensation."/jats:p" "jats:p"Fiber optic technology in subsea monitoring began over 20 years ago by migrating expertise from decommissioning of rocket motors. The first installations were on new installations of subsea pipelines, production risers, and drilling risers to measure strain and vibration for fatigue life monitoring. Of particular interest for these systems were detecting riser vortex induced vibration and strain throughout the touchdown zone. A prior limitation was that sensor installation was only performed top-side on new subsea equipment. This recent work demonstrates the capability to deploy on existing subsea equipment."/jats:p" "jats:p"The novel contributions of this study are the developments that optimize the clamp design, bonding techniques, and factors that allow long-term service life. Button pull tests validate long term service life after the clamps are subjected to accelerated aging tests. Details on the subsea calibration also provide insight on the recent progress with post-installed sensors."/jats:p" "jats:p"The purpose of reliable post-installed advanced sensors is not only to detect failures of subsea infrastructure but also to warn of signs of fatigue or hydrate formation that contribute to catastrophic failures. The calibration and testing mentioned in this paper are part of the Clear Gulf study, a collaboration formed in 2010 between the offshore energy industry and NASA. The study continues to make advances in highly sensitive monitoring systems that anticipate failures, catastrophic events, and flow assurance issues.

Remote Pipeline Pressure Monitoring Using Low Power Wireless Transmission

Scipedia content — Mon, 01 Feb 2021 15:50:40 +0100

Manual data acquisition of pressure readings in order to build a static pipeline hydraulic profile for a pipeline network, increases the security exposure of personnel, logistics cost with the attendant delay in determining and reporting pipeline pressure used in Hydrocarbon accounting, making it prone to errors, inaccurate and unrepresentative of the actual situations on the network. This paper presents results of a wireless pipeline real time (RT) pressure monitoring system using low power wireless transmitters installed at selected pressure points on the pipeline networks located in remote areas of SPDC operations. The system utilizes secure wireless transmission and special encryption systems designed to protect the data transmission from interference and degradation. The system achieved a data transmission over a 10km range from a pipeline pressure point to the gateway, with a battery life of over 6 months. Longer battery life durations can be achieved by the deployment of exception based reporting. The system provides a means of monitoring the pipeline pressure and thus enables the development of a dynamic pipeline pressure profile for the monitored pipelines. The data from the system can also be used with special algorithms to monitor the pipeline for leaks. The system versatility has also been tested as means of collating vital well data to a data concentrator enroute an enterprise intranet.

A bilevel mathematical programming model to optimize the design of cycle paths

Scipedia content — Fri, 29 Jan 2021 01:08:37 +0100

In this article, we present a methodology to simultaneously modelize car, bus, and bicycle transport modes, considering the interactions among the three modes through the modelling of the modal split and the network assignment of the different travels of each mode. Later, this model was utilized to optimize the design of cycling paths network to achieve an efficient and sustainable transport system. The proposed methodology has two levels. In the lower level there is a transport network, over which cars users, bus passengers and bicycles users could be simulated at the same time Applied to this is a combined model (modal split-assignment model) with its inputs come from a global matrix (car, bus and bicycle trips). The Multinomial Logit model for modal split and network assignment models will follow an iterative process, to provide the final matrices and service variables for each mode of transport. Finally, in the upper level, an optimization model has been developed, based on bilevel mathematical programming. The objective is to optimize the design of cycling paths, determining which typology of bike lane will be the optimal for each street. For this specific model, we considered only three typologies (segregated, non-segregated, and no bike lane). The optimization criteria utilized aims to maximize the number of cycling users. These have been applied to the real scenario of the city of Santander (Spain). The authors would like to acknowledge the financial support provided by the Spanish Ministry of Economía y Competitividad in project TRA2012-39466-C02-02

Three-Dimensional Trajectory Design for Reducing Climate Impact of Trans-Atlantic Flights

Scipedia content — Fri, 29 Jan 2021 01:03:31 +0100

The impact of aircraft emissions and contrails on the environment adds an additional aspect to aircraft trajectory optimization. This study developed a three-dimensional trajectory optimization algorithm for trans-Atlantic flights in cruise to generate aircraft trajectories that minimize environmental impacts due to CO 2 emissions and contrails in the presence of winds. The climate-optimal trajectory is developed using dynamic programming that adjusts a wind-optimal aircraft heading while determining the optimal locations, altitudes and times for en-route step climbs. Flying wind-optimal routes minimize aircraft travel time, fuel burn and associated emissions during cruise while adjusting aircraft heading and en-route step climbs at the optimal locations and times minimize climate impact of contrails. This capability integrates an air traffic management simulation with aircraft fuel burn and emissions models, contrail formation and dispersion models, simplified climate response models, and a common climate metric. A study was conducted to evaluate the potential cost and benefits of flying climate-optimal routes in North Atlantic Airspace and their impacts to the Organized Track System design based on the trans-Atlantic air traffic during a day, July 12, 2012. Results show eastbound flights achieved a larger environmental benefit with less additional fuel burn than westbound flights that operated in strong headwinds that caused more additional fuel burn and aircraft emissions to avoid traversing contrails favorable regions.

Sustainable transport systems: trends on needs, constraints, solutions

Scipedia content — Fri, 29 Jan 2021 01:01:50 +0100

In this historical moment, technology can guarantee transport systems some good solutions which seems to be quite in line with actual needs, by improving efficiency of engines (ICEs) or of travels or even rationalizing the consumption of related activities by using ITS (Intelligent Transport Systems) and by developing systems which can be sustainable through their whole life-cycle (LCC). Main results of the paper can be synthesised in pursuing the independence from the main source transport systems are based on, which is a nearly-monopoly, and use of lower unitary energy in motorised mobility in order to reduce the fuel consumption per person or per ton and - consequently - the emissions. This aim can be pursued either through higher capacity transport modes (e.g. trains, metros and automated people movers), yet guaranteeing as far as possible vehicles loaded more than their break-even in energy, or with a low level of black-oil energy used for vehicles: e.g., FEV, PHEV, natural gas for heavy-duty vehicles. The WTW analysis synthesises most of this idea.

Exploration of the Growing Trend of Electric Vehicles in Beijing with System Dynamics method and Vensim model

Scipedia content — Fri, 29 Jan 2021 01:00:46 +0100

This research is conducted to explore the growing trend of private vehicles in Beijing, China, in the coming 25 years using the system dynamics (SD) method. The vensim software is used to build the SD model and do simulations. First, the paper introduces the background of the private vehicles in Beijing and analyzes the issues of traffic congestion and air pollution caused by them. Second, the method system dynamics is justified to analyze the concerned issues of Beijing vehicle and the attendant traffic congestion and air pollution. Third, qualitative analysis is done to explore what possible policies the Beijing government can adopt to increase the percentage of electrical vehicles (EVs) and control the number of total private vehicles at the same time. A causal loop diagram is drawn to facilitate the way of thinking. Afterwards, a quantitative SD model about the system is built based on the causal loop diagram and qualitative analysis is made. Finally, the SD model is simulated to explore the plausible future trend about private vehicles and study the implications of different policies.

How to foster electric vehicle market penetration? A model based assessment of policy measures and external factors

Scipedia content — Fri, 29 Jan 2021 01:00:04 +0100

Electric vehicles (EVs) have the potential to reduce green house gas emissions from the transport sector. However, the future market evolution of EVs strongly depends on several influencing factors such as battery and oil prices as well as their future evolution. The effect of these and other influencing factors as well as the resulting future market evolution are uncertain, yet policy makers need an empirical basis to take decisions impacting the future market evolution. Here, we study the market evolution of EVs in Germany until 2020 and perform a model-based assessment of influencing factors and different monetary policy measures. We use an agent-based model with a utility maximising decision function for several thousand individual private and commercial vehicle owners. Our results reveal a great deal of uncertainty in the market evolution of EVs due to external conditions and the users’ willingness-to-pay for this new technology. Energy prices have a large impact on EV market evolution as a 25 % increase in fuel prices would double the number of EVs in stock by 2020 compared to a reference scenario. We find a special depreciation allowance for commercial vehicles and a subsidy of 1,000 Euro per vehicle to be the most effective and efficient monetary policy options. Furthermore, the high uncertainty of framework conditions and the EV market evolution implies that policies to foster market diffusion of EVs should be dynamically adaptable to react to changing framework conditions.

Hamilton-Jacobi formulation for reach-avoid problems with an application to air traffic management

Scipedia content — Fri, 29 Jan 2021 00:59:14 +0100

new framework for formulating reachability problems with nonlinear dynamics and state constraints as optimal control problems is developed. The work in this paper is motivated by such problems in the area of air traffic management, in particular the problem of collision avoidance in the presence of 4D constraints, called Target Windows, that the aircraft have to respect to meet their schedule. Earlier approaches to reach-avoid computations are either restricted to linear systems, or face numerical difficulties due to possible discontinuities in the Hamiltonian of the optimal control problem. The main advantage of the approach proposed in this paper is that it can be applied to nonlinear dynamics and has very good properties in terms of its numerical solution, since the value function and the Hamiltonian of the system are both continuous. The performance of the proposed method is demonstrated by applying it to conflict detection and resolution under Target Window constraints in a two aircraft scenario.

Understanding Sustainable Mobility: The Potential of Electric Vehicles

Scipedia content — Fri, 29 Jan 2021 00:57:08 +0100

Rising awareness of the environmental impacts of dominant mobility practices lead to the development of the sustainable mobility paradigm. This paradigm advocates three features of a mobility system: 1. A reduced need to travel, 2. Modal shift towards more sustainable options, and 3. Reduced vehicle kilometres travelled. In this paper, two sets of data are presented to explore the potential of electric vehicles to contribute to a more sustainable mobility system. First, data from an international Delphi of transport experts shows how a sustainable future can be characterised by different features: efficient internal combustion engine vehicles, electric vehicles, and reduced personal car ownership. Thus electric vehicles are presented as both an opportunity and a threat in relation to sustainable mobility. A second body of empirical material is drawn from interviews with electric vehicle owners, and discusses the drivers and barriers to ownership. Interestingly, participants suggest changing mobility practices associated with electric vehicle ownership, evidenced by decreasing kilometres travelled. The paper concludes by suggesting that there may be potential for electric vehicles to contribute to a sustainable mobility future through modified mobility practices and renewable energy sources in New Zealand.

Interactions between Operations and Planning in Air Traffic Control

Scipedia content — Fri, 29 Jan 2021 00:56:54 +0100

International audience; Air traffic in Europe is predicted to largely increase over the next decades. In such a context, this paper presents a study of the interactions between costs due to ground holding regulation and costs due to en-route air traffic control. With that in mind, a traffic simulator including the computations of regulation delays, aircraft trajectories and air conflict resolution is described. Through intensive simulations based on traffic forecasts extrapolated from 2012 historical French traffic data, regulation delays and avoidance manoeuvres are computed assuming the current regulation or no regulation at all. The resulting costs analysis highlights the exponential growth of regulation costs that should be expected if the airspace capacity and the involved procedure do not change. Compared to this, the costs of air traffic control remain negligible whether regulation is performed or not. The analysis of controllers' workloads however emphasizes the future need to combine automated tools assisting controllers with a regulation better adapted to bigger traffic volumes.

Soft vector processors with streaming pipelines

Scipedia content — Fri, 29 Jan 2021 00:52:30 +0100

Soft vector processors (SVPs) achieve significant performance gains through the use of parallel ALUs. However, since ALUs are used in a time-multiplexed fashion, this does not exploit a key strength of FPGA performance: pipeline parallelism. This paper shows how streaming pipelines can be integrated into the datapath of a SVP to achieve dramatic speedups. The SVP plays an important role in supplying the pipeline with high-bandwidth input data and storing its results using on-chip memory. However, the SVP must also perform the housekeeping tasks necessary to keep the pipeline busy. In particular, it orchestrates data movement between on-chip memory and external DRAM, it pre- or post-processes the data using its own ALUs, and it controls the overall sequence of execution. Since the SVP is programmed in C, these tasks are easier to develop and debug than using a traditional HDL approach. Using the N-body problem as a case study, this paper illustrates how custom streaming pipelines are integrated into the SVP datapath and multiple techniques for generating them. Using a custom pipeline, we demonstrate speedups over 7,000 times and performance-per-ALM over 100 times better than Nios II/f. The custom pipeline is also 50 times faster than a naive Intel Core i7 processor implementation.

An overview of current capabilities and research activities in the airspace operations laboratory at NASA ames research center

Scipedia content — Fri, 29 Jan 2021 00:50:36 +0100

The Airspace Operations Laboratory at NASA Ames conducts research to provide a better understanding of roles, responsibilities, and requirements for human operators and automation in future air traffic management (ATM) systems. The research encompasses developing, evaluating, and integrating operational concepts and technologies for near-, mid-, and far-term air traffic operations. Current research threads include efficient arrival operations, function allocation in separation assurance and efficient airspace and trajectory management. The AOL has developed powerful air traffic simulation capabilities, most notably the Multi Aircraft Control System (MACS) that is used for many air traffic control simulations at NASA and its partners in government, academia and industry. Several additional NASA technologies have been integrated with the AOL's primary simulation capabilities where appropriate. Using this environment, large and small-scale system-level evaluations can be conducted to help make near-term improvements and transition NASA technologies to the FAA, such as the technologies developed under NASA’s Air Traffic Management Demonstration-1 (ATD-1). The AOL’s rapid prototyping and flexible simulation capabilities have proven a highly effective environment to progress the initiation of trajectory-based operations and support the mid-term implementation of NextGen. Fundamental questions about accuracy requirements have been investigated as well as realworld problems on how to improve operations in some of the most complex airspaces in the US. This includes using advanced trajectory-based operations and prototype tools for coordinating arrivals to converging runways at Newark airport and coordinating departures and arrivals in the San Francisco and the New York metro areas. Looking beyond NextGen, the AOL has started exploring hybrid human/automation control strategies as well as highly autonomous operations in the air traffic control domain. Initial results indicate improved capacity, low operator workload, good situation awareness and acceptability for controllers teaming with autonomous air traffic systems. While much research and development needs to be conducted to make such concepts a reality, these approaches have the potential to truly transform the airspace system towards increased mobility, safe and efficient growth in global operations and enabling many of the new vehicles and operations that are expected over the next decades. This paper describes how the AOL currently contributes to the ongoing air transportation transformation.

Optimization of Charging Strategies for Electric Vehicles in PowerMatcher-Driven Smart Energy Grids

Scipedia content — Fri, 29 Jan 2021 00:47:50 +0100

crucial challenge in future smart energy grids is the large-scale coordination of distributed energy demand and generation. The well-known PowerMatcher is a promising approach that integrates demand and supply flexibility in the operation of the electricity system through dynamic pricing and a hierarchical bidding coordination scheme. However, as the PowerMatcher focuses on short-term coordination of demand and supply, it cannot fully exploit the flexibility of e.g. electric vehicles over longer periods of time. In this paper, we propose an extension of the PowerMatcher comprising a planning module, which provides coordinated predictions of demand/price over longer times as input to the users for determining their short-term bids. The optimal short-term bidding strategy minimizing a user's costs is then formulated as a Stochastic Dynamic Programming (SDP) problem. We derive an analytic solution for this SDP problem leading to a simple short-term bidding strategy. Numerical results using real-world data show a substantial performance improvement compared to the standard PowerMatcher, without significant additional complexity.

Conception and Design of Mobile Driving Simulators

Scipedia content — Fri, 29 Jan 2021 00:44:37 +0100

Driving simulators (DS) are an indispensable developmental tool in the automotive industry. Versatile areas of application all profit from the high degree of reproducibility and safety of DS. The upcoming demands for advanced driver assistance systems (ADAS) with respect to urban traffic situations result in increasing DS requirements in regard to motion envelope and system dynamics [1]. To fulfill those increased requirements, modern-day DS show up to 12 degrees of freedom (DOF) whilst comprising multiple drive mechanisms. These improvements come with the disadvantage of creating a complex system with increased moving mass of about 80 t. Thus, a link between moving mass and motion envelope is caused, limiting either motion envelope or system dynamics."/jats:p" "jats:p"Mobile dynamic DS solve the core problem of the increased moving mass. The proposed design of a Wheeled Mobile Driving Simulators (WMDS) shows three self-propelled and active steerable wheels that allow translational motion and yaw [2]. The main idea is based on the assumption that a wheeled system, whose propulsion is limited by friction forces, is suitable to simulate dynamics of vehicles that are also limited by tire friction forces. An additional system provides cabin tilt. Avoiding the conventional rail systems, which mainly cause the moving mass increase, results in a light weight concept [3]. The design and construction of the WMDS are carried out at the Institute of Automotive Engineering (Fahrzeugtechnik Darmstadt: FZD), Germany since 2010."/jats:p" "jats:p"This paper shows the evaluation of a suitable design — by the standards of modern product development — in general for mobile dynamic DS and specifically for WMDS. Furthermore, this paper shows the selection of the individual components and overall properties as well as limitations of the prototype.

Study on Transportation Problem in Green Logistics

Scipedia content — Fri, 29 Jan 2021 00:36:42 +0100

By far, logistics has had more than 100-year development history since it was put forward by Johnsy Baker in 1905 in Troops and Transportation of Munitions. Most logistics mentioned by people in daily life are modern logistics which means a new-type integrated management combining all logistics activities such as information, transportation, storage, warehousing, handling as well as package and so on. In the west, logistics has been developed into a mature operative mode with wide development in practice as economic pillar and black house in service industry. The world industry has been turned to informatization from industrialization after experiencing industrial revolution, leading to today's green and sustainable development. With the increasingly more attention paid to greenhouse effect, the concept of low-carbon and sustainable development has also become more and more mature

Numerical Modeling of Pipe-Soil Interaction Under Transverse Direction

Scipedia content — Fri, 29 Jan 2021 00:24:19 +0100

Based on the Winkler method, a pipe can be treated as a beam, and pipe-soil interactions can be represented by soil springs in the axial, horizontal and vertical directions. Pipe deflection and resultant forces are correlated by coefficient K in the equation F=Kδ, where F is the resultant force and δ is the pipe displacement. This paper studies pipe-soil interaction for pipelines buried in clay and sand subjected to displacements in oblique directions. The objective is to measure the effect of soil parameters on coefficient K as well as the maximum soil resistance. Pipe-soil behavior has been studied using the finite element software ABAQUS/CAE. There are 48 models in total with varying soil parameters, pipe burial depth and pipe-soil interaction friction for the investigation of the effect of each variable on pipe-soil behavior. In addition, the finite element results have been compared to the analytical results from American Lifelines Alliance guideline (ALA, 2001) and proposed failure envelopes in previous studies.Copyright © 2014 by ASME

Recursive State Estimation for Lane Detection Using a Fusion of Cooperative and Map Based Data

Scipedia content — Fri, 29 Jan 2021 00:23:14 +0100

Modern automated and cooperative driver assistance systems (CoDAS) rely deeply on the position estimation. Regardless of absolute positioning accuracy, the relative position in regard to driving environment and other vehicles needs to be of high quality to enable sophisticated functions. Global Navigation Satellite Systems (GNSS) fulfill this demand only partially. In this paper we present an algorithm to accurately infer the driving lane by utilizing Dedicated Short Range Communication (DSRC) and map data alone. We evaluate our approach against simulated and real-life data from Europes largest cooperative vehicle Field Operational Test (FOT): simTD. This lane detection algorithm will be an enabler for CoDAS functions like collaborative driving and merging developed in the TEAM IP project.

R-curve evaluation of pipeline girth welds using advanced measurement techniques

Scipedia content — Fri, 29 Jan 2021 00:21:47 +0100

A strain-based flaw assessment procedure is recommended for girth welded pipelines subjected to large deformations. To evaluate the allowable defect dimensions, the tearing resistance needs to be characterized. This paper investigates the effect of weld metal strength mismatch on the resistance curve using Single Edge Notched Tension (SENT) specimens. Several advanced measurement techniques are applied during the tests in order to obtain a continuous measurement of crack extension and to visualize the deformation fields near the crack. The resistance curves are determined using a single specimen technique. The unloading compliance method and the potential drop method result in similar predictions of ductile crack extension, yielding similar resistance curves. Next to these measurements, the full field deformations are determined using digital image correlation. The experiments indicate that the position of the applied notch in the weld has the potential to influence the strain fields.

Distributed road traffic congestion quantification using cooperative VANETs

Scipedia content — Fri, 29 Jan 2021 00:17:24 +0100

The well-known traffic congestion problem in urban environments has negative impact on many areas including economy, environment, health and lifestyle. Recently, a number of solutions based on vehicle-to-vehicle communications were proposed for traffic congestion detection and management. In this paper we present an algorithm designed to enable each vehicle in the network to detect and quantify the level of traffic congestion in completely distributed way, independent of any supporting infrastructure and additional information such as traffic data from local authorities. Based on observations of traffic congestion by every vehicle, and by adapting the broadcast interval, it enables dissemination of the traffic information to other vehicles. The algorithm also makes every vehicle aware about the congestion level on the streets that are spatially separated from their current location by several streets. Its robustness keeps the vehicle's overall knowledge about congestion consistent, despite the short-term changes in vehicle's motion. Since the quantification of congestion is based on per-vehicle basis, the algorithm is able to operate even when only 10% of vehicles in the network are VANET enabled. Data aggregation and adaptive broadcasting are used to ensure that vehicles do not send redundant information about the traffic congestion. The simulations are conducted in Veins framework based on OMNeT++ network simulator and SUMO vehicular mobility simulator.

Coordination between sectors in shared airspace operations

Scipedia content — Fri, 29 Jan 2021 00:06:04 +0100

Recent studies have shown that a more efficient use of airspace may involve shared airspace operations, i.e., temporal as well as spatial separation of arrival and departure flows [1][2]. Temporal separation would permit a departure aircraft to fly through an arrival flow, depending on an available gap. This would necessitate careful and precise coordination between controllers in different sectors. Three methods of coordination which permit the penetration of a controller's airspace by another controller's aircraft are described: point out, lookand-go, and prearranged coordination procedure. Requirements of each method are given, along with associated problems that have surfaced in the field as described by Aviation Safety and Reporting System (ASRS) and other reports. A Human-in-the-Loop simulation was designed to compare two of the methods: point out and prearranged coordination procedures. In prearranged coordination procedures (P-ACP), the controllers control an aircraft in another controller's airspace according to specified prearranged procedures, without coordinating each individual aircraft with another controller, as is done with point outs. In the simulation, three experienced controllers rotated through two arrival sectors and a non-involved arrival sector of a Terminal Radar Approach Control (TRACON) airspace. Results of eighteen one-hour simulation runs (nine in each of the two conditions) showed no impact of the coordination method on separation violations nor in arrival times for 208 departing aircraft crossing an arrival stream. Participant assessment indicated that although both coordination conditions were acceptable, the prearranged coordination procedure condition was slightly safer, more efficient, timely, and overall, worked better operationally. Problems arose in the point out condition regarding controllers noticing acceptance of point outs. Also, in about half of the point-out runs, time pressure was felt to have had an impact on when and if the departures could cross an arrival stream. An additional problem with point outs may be confusion in the field about which controller has responsibility for separating point-out aircraft from other aircraft.

Automated Deviation Analysis for As-Built Status Assessment of Steel Assemblies and Pipe Spools

Scipedia content — Fri, 29 Jan 2021 00:03:58 +0100

Steel assemblies and pipe spools play an essential role in the industrial construction sector. Fabrication of steel assemblies has been a challenging task due to the limited fabrication precision of the tools used in the process and inadequate inspection during fabrication. Moreover, unfavorable deformations may occur during the transportation phase which makes the erection and installation phase more complicated. These deviations require further considerations for realignment and repair that are associated with rework on construction sites. Hence, a systematic and automatic framework is required to continuously monitor the fabrication and installation processes of steel assemblies. Current approaches lack a sufficient level of control and are prone to error. This paper presents an automated framework to detect defective parts in steel assemblies and pipe spools in particular. A laser-based point cloud, which represents the as-built status, is compared to the original state from the CAD drawings that exist in the Building Information Model (BIM). Therefore, the defective parts are detected in a timely manner. The comparison is distance based and the procedure is fully automated. The experiments conducted to validate the proposed approach show that the model has high precision and a high rate of recall and has the potential to be employed for automated damage detection in order to improve productivity on construction sites. PROBLEM STATEMENT Steel structural assemblies are one of the critical components in both residential and industrial construction. Pipe spools are also key components for most industrial construction projects such as refineries and power plants. Utilizing steel structural assemblies on construction sites requires accurate fabrication and incident free shipment to site. Due to the advantages that staged fabrication of modules provides such as a controlled environment for fabrication, improved safety and improved

A Tactical Separation Assurance System for Terminal Airspace

Scipedia content — Fri, 29 Jan 2021 00:03:37 +0100

tactical separation assurance prototype system is evaluated for its fitness to support the Standard Terminal Automation Replacement System (STARS) in a complex terminal airspace environment that includes a mix of visual- and instrument-approach aircraft, Mode C intruders, and limited trajectory-intent data. Fast-time simulation experiments using air traffic data from human-in-the-loop simulations and live Terminal Radar Control (TRACON) operations featuring a mix of visual and instrument approaches and Mode C intruders are performed to assess the performance and benefits of the system in a near-term national airspace system (NAS). It is found that nuisance alerts attributable to aircraft on visual approach are eliminated with a high-severity alerting option. With a normal lowseverity alerting option, Mode C intruder alerts are reduced more than 50% as compared to the Conflict Alert system, a legacy function in STARS. The trajectory intent information that is most effective in reducing false alerts is identified and found to be available in STARS or easily adapted from existing NAS automation.

Analysis of Airport Ground Delay Program Decisions Using Data Mining Techniques

Scipedia content — Fri, 29 Jan 2021 00:02:06 +0100

traffic service providers have to make decision s regarding changes to air traffic flow in the event of major weather dist urbances and traffic congestions to maintain safety of the system. The b ehavior of the air traffic management system will be more predictable if consistent decisions are made under similar traffic and weather conditions. Consi stency of deciding on control action depends on the weather and traffic c onditions as well as accuracy in predicting these conditions. Weather parameters (defined in terms of forecast and actual weather and traffic co nditions) on different days can be used to categorize these into days with litt le decision consistency, days with moderate decision consistency and days with high decision consistency. Five years of traffic, weather and ground delay pro gram decisions data at major airports in the United States are used in the analysis. This paper examines performance of different data mining methods in the three regions of decision consistency. Not surprisingly, data mi ning methods have the best performance in the region of most decision consiste ncy and have the poorest performance in the region of little decision consis tency. In applications where data mining methods have differing performance in differing regions, it would be more useful to characterize region specifi c performance instead of characterizing performance by a single parameter. Finally, the results show no significant variation in the performance of diff erent data mining methods for this particular problem. The fact that differe nt mining methods show no significant variation also provides further confide nce in the results of data mining methods. This paper also discusses how prediction errors impact regions of decision consistency.

Complete vehicle energy management with large horizon optimization

Scipedia content — Thu, 28 Jan 2021 23:56:16 +0100

In this paper, we extend the dual decomposition approach to Complete Vehicle Energy Management (CVEM) with novel solution methods to reduce computation time. The CVEM problem is solved for a case study of a hybrid heavy-duty vehicle, equipped with an electric machine, a high-voltage battery system and a refrigerated semi-trailer, by combining two solution methods. The first proposed solution method is to apply another decomposition on top of the dual decomposition that was proposed before. This additional decomposition is based on the Alternating Direction Method of Multipliers. The second proposed solution method uses the Lagrangian Method that is best suited for systems whose optimal state trajectory has limited contact points with its constraints. The computational efficiency is demonstrated by solving the problem for a drive cycle with 88656 time steps in 29 minutes. Moreover, we show that for a drive cycle of 2000 time steps, the computation time can be reduced with a factor 100, when compared to the previously proposed dual decomposition approach.

Investigation on the Effects of Environmental and Operational Conditions (EOC) on Diffuse-Field Ultrasonic Guided-Waves in Pipes

Scipedia content — Thu, 28 Jan 2021 23:55:03 +0100

In spite of many favorable characteristics of guided-waves for Nondestructive Evaluation (NDE) of pipes, real-world application of these systems is still quite limited. Beside the complexities derived from multi-modal, dispersive and multi-path characteristics of guided-waves, one of the main challenges in guided-wave based NDE of pipelines is sensitivity of these systems to variations of environmental and operational conditions (EOC). This paper investigates the effects of varying EOCs on guilded-wave based NDE of pipelines. We first provide a review of the studies to date in the field of guided-wave based testing to identify research gaps for enhancing the application of these systems in pipeline NDE. To study the identified gaps, guided-wave data from a fully operational piping system, with continuously varying flow rate and temperature, is used. Time-shift and amplitude drift effects due to flow rate variations are evaluated along with those of temperature. It is observed that masking effects of flow rate for damage detection can be at least as significant as temperature effects, and that such effects become more dominant when flow rate and temperature variations co-occur.

Assessing positional accuracy of drainage networks extracted from ASTER, SRTM and OpenStreetMap

Scipedia content — Thu, 28 Jan 2021 23:48:32 +0100

This study intends to evaluate the positional accuracy and compare the completeness of the drainage networks extracted from three sources of free geographic data, namely from the Digital Elevation Models ASTER and SRTM and the collaborative project OpenStreetMap (OSM), in an area included in the basin of Mondego river, located in the centre of continental Portugal. The drainage networks extracted from ASTER and SRTM are generated considering several values of flow accumulation as the critical level to identify the water courses and the feature “waterway” was extracted from OSM. To assess the completeness and positional accuracy of these water courses the drainage network of the 1/25000 topographic map of the Portuguese Army Geographical Institute was used as reference. The distance between the ASTER, SRTM and OSM derived water courses to the reference data was computed as well as the length of the water courses and the results compared.

Pathways to an oil-constrained sustainable city

Scipedia content — Thu, 28 Jan 2021 23:47:19 +0100

The global production of conventional oil is predicted to have reached a peak plateau in the first decade of this century and will gradually decline, while demand outstrips the discovery and exploitation of new oil sources. Current oil strategies are geared to mitigation actions, but adaptive measures will become more important in the longer term future as oil supply becomes constrained. This paper reports the grounded theory research of a PhD investigation into adapting urban residential development to an oil-constrained future, in the Australian and wider context. The planning research is grounded in a general theoretical framework of sustainable development theory, encompassing urban metabolism and material flow analysis. European pre-oil economy cities form the basis for development of four grounded theories and a conceptual framework model about the characteristics of an oil-constrained sustainable city. The framework provides the basis of a tool for integrating the effects of oil constraints into the urban metabolism for sustainable planning and development. These theories and model will assist spatial planners to guide transformation of urban residential forms towards a transitional city of tomorrow and an oil-constrained city of the future.

On-board electric vehicle battery charger with enhanced V2H operation mode

Scipedia content — Thu, 28 Jan 2021 23:43:19 +0100

This paper proposes an on-board Electric Vehicle (EV) battery charger with enhanced Vehicle-to-Home (V2H) operation mode. For such purpose was adapted an on-board bidirectional battery charger prototype to allow the Grid-to-Vehicle (G2V), Vehicle-to-Grid (V2G) and V2H operation modes. Along the paper are presented the hardware topology and the control algorithms of this battery charger. The idea underlying to this paper is the operation of the on-board bidirectional battery charger as an energy backup system when occurs a power outages. For detecting the power outage were compared two strategies, one based on the half-cycle rms calculation of the power grid voltage, and another in the determination of the rms value based in a Kalman filter. The experimental results were obtained considering the on-board EV battery charger under the G2V, V2G, and V2H operation modes. The results show that the power outage detection is faster using a Kalman filter, up to 90% than the other strategy. This also enables a faster transition between operation modes when a power outage occurs. Fundação para a Ciência e Tecnologia (FCT), Project Scope: Pest OE/EEI/UI0319/201

Bayesian predictive assistance system: An embedded application for resource optimization in industrial cleaning processes

Scipedia content — Thu, 28 Jan 2021 23:41:28 +0100

Bayesian networks (BNs) have been used in different contexts of decision support solutions such as directive, strategic, tactical and operational. These contexts differ from each other only in the realization of the decision support in terms of time. The real-time implementation of BN in an embedded system for resource optimization is very challenging because of the low computation capacity in embedded systems and, to the best of our knowledge, has not been reported yet. In this paper, we present a BN based predictive assistance system that uses real-life data to perform the real-time decision support in industrial cleaning processes.

Impact of Ethernet Multipath Routing on Data Center Network Consolidations

Scipedia content — Thu, 28 Jan 2021 23:40:14 +0100

International audience; —With the advent of network virtualization, data center networking is reaching a high level of management complexity. Indeed, interconnection networks in data center networks (DCN) are no longer just based on flat over-provisioned pipes, but are increasingly facing traffic engineering (TE) issues that commonly characterize long-haul provider networks. TE objectives, however, are opposite to energy efficiency (EE) objectives commonly chased by virtual machine (VM) consolidations. Moreover, the specific topologies of DCNs and the systematic use of multipath forwarding make the joint TE and VM consolidation optimization complex. The contribution of this paper is twofold. First, we propose a repeated matching heuristic for the DCN optimization problem with multipath capabilities, which also scales well for large topologies without discarding both TE and EE objectives. Second, we assess the impact of multipath forwarding on TE and EE goals. Extensive simulations show us that multipath forwarding is beneficial only when EE is not the primary goal in network-aware VM consolidations, and that it can be counterproductive when instead the EE is the primary goal of such optimizations.

SMART Pressure Regulation In Main Oil Pipeline

Scipedia content — Thu, 28 Jan 2021 23:36:28 +0100

Regulation with help of simultaneous using of pump and valve in applying to main oil pipeline pressure control is researched in the article. An energy efficient mode for this system is being calculated. Article describes an algorithm and an idea of economic pressure stabilization. Keywords-Pressure control; valve; automatic control; pump; frequency controlling. I. INTRODUCTION Main pipeline pumps are difficult technical constructions and play crucial part in oil pipeline transportation. Parts of them are intended for oil supply form buster pumps to main pipeline. And others are used for energy losses replenishment during pressure control and also for pipeline hydrodynamic separation on given in draft sectors to provide pumping and hydra impact effects localization in main pipeline. The main problem of oil transportation is pressure maintenance set by regulatory requirements. The recent time tendency of pressure regulation is controlling pressure by pump rotating speed changing. To provide desired operating mode main pump stations include serially connected pumps, which are controlled with frequency adjustable motors with high power consuming. This power depends on an oil supply volume in pipeline Q and value of pressure H

A review and framework of Control Authority Transitions in automated driving

Scipedia content — Thu, 28 Jan 2021 23:27:44 +0100

The paper reviews some of the essentials of human-machine interaction in automated driving, focusing on control authority transitions. We introduce a driving state model describing the human monitoring level and the allocation of lateral and longitudinal control tasks. An authority transition in automated driving is defined as the process of changing from one static state of driving to another static state. Based on (1) who initiates the transition and (2) who is in control after the transition, we categorize transitions into four types: driver-initiated driver control (DIDC), driver-initiated automation control (DIAC), automation-initiated driver control (AIDC), and automation-initiated automation control (AIAC). Finally, we discuss the effects of human-machine interfaces on driving performance during transitions.

Automatic Pipeline Generation by the Sequential Segmentation and Skelton Construction of Point Cloud

Scipedia content — Thu, 28 Jan 2021 23:26:12 +0100

Point clouds are the main output of automatic data collection using laser-scanner technologies. The large numbers of points scanned from pipeline plants make the plant reconstruct very difficult. We have developed a system based on the Point cloud Library (PCL), to find, recognize and reconstruct 3D pipes within point-clouds fully automatically. The proposed approach consists of pre-processing point cloud data, segmentation, skeleton extraction and automatic cylinder fitting for pipeline. The presented results shows that the proposed method enables reliable 3D models of pipelines, which could be successfully incorporated into the reconstruction of a plant information modelling method and utilized for, assist maintenance and expansion of existing plants.

ESTIMATION OF THE CONVECTIVE HEAT TRANSFER COEFFICIENT IN PIPELINES WITH THE MARKOV CHAIN MONTE CARLO METHOD

Scipedia content — Thu, 28 Jan 2021 23:20:52 +0100

Could the increased use of e-bikes (pedelecs) in Sweden contribute to a more sustainable transport system?

Scipedia content — Thu, 28 Jan 2021 23:18:37 +0100

The transport sector accounts for large proportions of greenhouse gas emissions and energy usage in Sweden, about 40% and 30%, respectively. Most of this, 93%, comes from road transports. There is, therefore, a strong political desire to reduce the use of fossil fuels in road transport. Several alternatives to fossil fuels have been discussed and, more recently, interest in electrically driven vehicles has increased substantially. Numerous studies have been made with respect to electric cars, but there is insufficient knowledge about the use of electrically assisted bicycles. With increased knowledge of the potential of these new bicycles, society can better meet the new trend. The main aim here is to present the effects of pedelec (in this paper referred to as e-bike) usage on CO2 emissions. Based on a web questionnaire sent to users of /e-bikes, this paper also attempts to gain insight into the actual usage and users' motives for buying e-bikes. The survey uses a sample consisting of customers who bought e-bikes through a retailer in Sweden. The results indicate that, contrary to other European studies, the majority of users switched from using their cars to e-bikes. Furthermore, most of the users were men with a driver's license and good access to a car. Calculations suggest that there are large gains to be made in terms of decreased CO2 emissions through a reduction in car mileage. Considering the CO2 reduction potential, and that e-bikes seem to attract men with good access to a car, the results are very interesting indeed. However, the survey is based on a small sample from a single retailer, and to what extent these users mirror the average e-bike user in Sweden is open to question. On the other hand, there is scant evidence to suggest that this would not be the case if standardized e-bikes are focused on. (Less)

A real-time implementable model-predictive cruise controller for electric vehicles and energy-efficient driving

Scipedia content — Thu, 28 Jan 2021 23:16:44 +0100

International audience; This paper presents a novel energy-efficient model-predictive cruise control formulation for electric vehicles. The controller and the underlying dynamic model are designed to meet the properties of a series-production electric vehicle whose characteristics are identified by measurements. A predictive eco-cruise controller involves the minimisation of a compromise between terms related to driving speed and energy consumption which are in general both described by nonlinear differential equations. In this work, a coordinate transformation is used which leads to a linear differential motion equation without loss of information. The energy consumption map is approximated by the maximum of a set of linear functions which is implicitly determined in the optimisation problem. The reformulations finally lead to a model-predictive control approach with quadratic cost function, linear prediction model and linear constraints that corresponds to a piecewise linear system behaviour and allows a fast real-time implementation with guaranteed convergence. Simulation results of the MPC controller and the simulation model in closed-loop operation finally provide a proof of concept.

Optimal Routing of Energy-aware Vehicles in Networks with Inhomogeneous Charging Nodes

Scipedia content — Thu, 28 Jan 2021 23:12:31 +0100

We study the routing problem for vehicles with limited energy through a network of inhomogeneous charging nodes. This is substantially more complicated than the homogeneous node case studied in [1]. We seek to minimize the total elapsed time for vehicles to reach their destinations considering both traveling and recharging times at nodes when the vehicles do not have adequate energy for the entire journey. We study two versions of the problem. In the single vehicle routing problem, we formulate a mixed-integer nonlinear programming (MINLP) problem and show that it can be reduced to a lower dimensionality problem by exploiting properties of an optimal solution. We also obtain a Linear Programming (LP) formulation allowing us to decompose it into two simpler problems yielding near-optimal solutions. For a multi-vehicle problem, where traffic congestion effects are included, we use a similar approach by grouping vehicles into "subflows". We also provide an alternative flow optimization formulation leading to a computationally simpler problem solution with minimal loss in accuracy. Numerical results are included to illustrate these approaches.

Comment: To appear in proceeding of 22nd Mediterranean Conference on Control and Automation, MED'14

An international crowdsourcing study into people's statements on fully automated driving

Scipedia content — Thu, 28 Jan 2021 22:55:07 +0100

Fully automated driving can potentially provide enormous benefits to society. However, it has been unclear whether people will appreciate such far-reaching technology. This study investigated anonymous textual comments regarding fully automated driving, based on data extracted from three online surveys with 8,862 respondents from 112 countries. Initial filtering of comments with fewer than 15 characters resulted in 1,952 comments. The sample consisted primarily of males (74%) and had a mean age of 32.6 years. Next, we launched a crowdsourcing job and asked 69 workers to assign each of the 1,952 comments to at least one of 12 predefined categories, which included positive and negative attitude to automated driving, enjoyment in manual driving, concerns about trust, reliability of software, and readiness of road infrastructure. 46% of the comments were classified into the category ‘no meaningful information about automated driving’, leaving 792 comments for further analysis. 39% of the comments were classified as ‘positive attitude towards automated driving’ and 23% were classified as ‘negative attitude towards automated driving’. In conclusion, the public opinion appears to be split, with a substantial number of respondents being positive and a significant number of respondents being negative towards fully automated driving.

Characterization of Nationwide TRACON Departure Operations

Scipedia content — Thu, 28 Jan 2021 22:53:19 +0100

This paper presents a characterization study focused on nationwide TRACON departure operations. It assesses shortfalls of present-day operations and identifies the potential benefits of improving TRACON departure scheduling. To characterize present-day TRACON operations across the National Airspace System, an analysis of National Traffic Management Logs is performed along with interviews of operational subject matter experts and firsthand observations at a TRACON facility. The focus of the study is on miles in trail restrictions applied at the departure fix, as well as the process of compressing and swapping departure fixes and gates. The study shows that departure fix restrictions are frequently used and that implementation of these restrictions can be complex and workload-intensive. Also, significant facility-to-facility variation in the implementation of departure restrictions makes this problem even more challenging. The nationwide analysis shows that the top thirteen TRACONs issued more than 2,700 departure fix restrictions during the month of July 2013, affecting more than 28,000 flights. A substantial amount of delay was incurred by flights subject to these departure fix restrictions, totaling more than 4,700 hours for the month studied.

Survey and Classification of Cooperative Automated Driver Assistance Systems

Scipedia content — Thu, 28 Jan 2021 22:43:11 +0100

The introduction of dedicated short-range Vehicle- to-Vehicle communication (DSRC) enables the next step in advanced driver assistance systems (ADAS) - the cooperative automated driver assistance systems (CoDAS). Combined with automated functions and even autonomous driving, a host of novel functions become feasible. Some of these - such as platooning- have been in research for decades, while others are not tackled yet. In this paper we give an overview on research on automated cooperative functions, survey conceivable functions and present a way to classify them.

The modes of government guidance for public bicycle operation and state-owned company operation: a case study of Hangzhou city in China

Scipedia content — Thu, 28 Jan 2021 22:31:59 +0100

The amount of public bicycle use in China has rapidly increased in the last ten years. By the end of 2013, public bicycle projects were operating in at least 70 cities, and there are more than 6 cities with a bicycle population exceeding 10 thousand. However, the local governments implement different public bicycle operation modes, which result in different effects. In this paper, four modes are summarized, including the Beijing mode of company operation, the Wuhan mode of company operation and government limited support, the Shanghai mode of company operation and government purchase, and the Hangzhou mode of government guidance and state-owned company operation. The Hangzhou case study shows that the Hangzhou mode is the best choice for China. Hangzhou is running the largest public bicycle program to date with a noticeable impact in the world. By 2013, 69,750 bikes are used with an average of 5.5 times each day. Most programs have not shown to be economically sustainable while Hangzhou is an exception. The rental, advertising and exporting of techniques guarantee the balance of expense and income in Hangzhou program. Economical sustainability is the key factor of successful application of Hangzhou mode. In future program planning, the authors suggest that bicycle transportation should be included in the public transportation system, while government guidance and state-owned company operation is the most healthful mode for most of public bicycle projects due to its public service attribution. Moreover, based on the survey results 57.14% cyclers are not against the increase of rental, the authors suggest that the rental can be adjusted to improve the income for city-transit policy makers.

SideEye: Mobile assistant for blind spot monitoring

Scipedia content — Thu, 28 Jan 2021 22:28:16 +0100

Distracted driving is an ever growing concern and driver safety systems are increasingly getting adopted. However, they still remain as features in the luxury vehicles. The high penetration of smartphones has made it possible to bring some of those safety features within everyone's reach. While some of the recent works have proposed tracking the road conditions as well as monitoring the driver with a smartphone, they have not covered the blind spot. In this paper, we present SideEye, a smartphone based system to monitor the blind spot on the driver side and alert the driver about the presence of a vehicle. We explore two approaches based on intensity variation and contour matching to detect a vehicle in the blind spot. Our evaluation shows that, when a vehicle is in the blind spot, our system can detect and alert the driver with an accuracy of 87% in real-time.

Temporal State Management for Supporting the Real-Time Analysis of Clinical Data

Scipedia content — Thu, 28 Jan 2021 22:26:20 +0100

Database systems are more and more employed to analyze an ever increasing amount of temporal data by applying a continuously evolving knowledge and are expected to do this in a timely fashion. Examples are financial services, computer systems monitoring, air traffic monitoring, and patient care. In each of these cases data are processed in order to understand current situations and to determine optimal responses. In this paper, we exemplarily investigate system requirements for a patient care scenario in which patient data are continuously collected and processed by a database system. We show that the concepts provided by today's systems are still not enough for supporting the complex reasoning process needed. In particular, we identify situation-based reasoning as a missing database component and propose a temporal state concept for leveraging simple event processing. States provide a high level (and qualitative) description of past and current situations defined over streams of medical data, complemented by projections into the future. Our proposed database extension allows for a compact and intuitive representation of medical data; much like physicians use abstraction from details and dramatically simplifies the analysis of medical data.

On the complexity of optimal electric vehicles recharge scheduling

Scipedia content — Thu, 28 Jan 2021 22:25:13 +0100

International audience; The massive introduction of Electric Vehicles (EVs) is expected to significantly increase the power load experienced by the electrical grid, but also to foster the exploitation of renewable energy sources: if the charge process of a fleet of EVs is scheduled by an intelligent entity such as a load aggregator, the EVs' batteries can contribute in flattening energy production peaks due to the intermittent production patterns of renewables by being recharged when energy production surpluses occur. To this aim, time varying energy prices are used, which can be diminished in case of excessive energy production to incentivize energy consumption (or increased in case of shortage to discourage energy utilization). In this paper we evaluate the complexity of the optimal scheduling problem for a fleet of EVs aimed at minimizing the overall cost of the battery recharge in presence of time-variable energy tariffs. The scenario under consideration is a fleet owner having full knowledge of the customers' traveling needs at the beginning of the scheduling horizon. We prove that the problem has polynomial complexity, provide complexity lower and upper bounds, and compare its performance to a benchmark approach which does not rely on prior knowledge of the customers' requests, in order to evaluate whether the additional complexity required by the optimal scheduling strategy w.r.t. the benchmark is worthy the achieved economic advantages. Numerical results show considerable cost savings obtained by the optimal scheduling strategy.

An international crowdsourcing study into people's statements on fully automated driving

Scipedia content — Thu, 28 Jan 2021 22:16:21 +0100

An Efficient Elephant Flow Detection with Cost-Sensitive in SDN

Scipedia content — Thu, 28 Jan 2021 22:02:02 +0100

The software defined networking (SDN) allows separating control and data plane, which provides better network management and higher utilization for data center network. Among these topical applications in SDN, such as traffic engineering, QoS and network management, there is significant interest on classifying the flows and predict future traffic. Classification plays an important role in SDN, especially for elephant flow detection. However, how to efficiently detect all kinds of flows with low cost still remains a challenge task in current researches. To address this issue, in this paper, we propose to introduce cost-sensitive learning method to define a real-time elephant flow detection strategy and the subsequent metric in flow detection. Then we apply our strategy to train and evaluate cost-sensitive decision trees in SDN. Extensive experiments on different settings and data sets have been performed, showing that our strategy is good at detecting elephant flow with high detection rates and low overhead.

Research on Passenger Market Competitiveness of China High Speed Railway and Railway Traffic

Scipedia content — Thu, 28 Jan 2021 21:39:29 +0100

High speed railway (HSR) in China will have a rapid growth in the following years. This paper first analyzes the different technological and economic characteristics of HSR, railway, air traffic and highway traffic and finds their unique comparative travelling distances. And then, three representative categories of O-D distances are studied. Specially, when HSR improves its speed from 300 km/h to 350 km/h, the competitive O-D distance extends from 1000km to 1300km. Considering competition and cooperation of HSR and railway traffic, it is suggested transforming the prevailing management mechanism and get adapted to the transportation market competition.

An applicable model for establishing sustainable traffic

Scipedia content — Thu, 28 Jan 2021 21:31:51 +0100

Solving transport problems in the cities assumes the implementation of regulatory measures and a complex of technological, operational and economic measures. The improvement of transport conditions in urban areas is a precondition for their sustainable development. Regulative harmonization and regional infrastructure development is a necessary precondition in the integration process and in adopting the best practices in the organization of local (urban) transport. This paper deals with the problems of modelling urban public transport with regard to the principle of the sustainability of transport development, which integrates the objectives of mobility, physical planning and environmental protection in transport policy. The models for the improvement of urban transport in the projects realized are analogously applicable at a regional level. This fact is of great importance for the regulatory harmonization, strategic planning and policy development of urban transport management in Croatia.

Crafting Soft Geometry Form and Materials Informing Analog and Digital Craft Processes

Scipedia content — Thu, 28 Jan 2021 21:31:37 +0100

This paper outlines a methodology that adds to current craft-based discourse in the digital age. It proposes pedagogy centered on a constant examining of the parametric relationships between form, material, and load. The paper illustrates how materials and loads were integrated as datasets into “soft geometry” modeling and installation pipelines that further explore a hybrid process that incorporates materials and craftsmanship. The results expand the boundary of conventional static form and spatial interaction within the deformation rules (material and force) while seeking form through the exploration of both digital simulation and analog techniques.

Effect of traffic position accuracy for conducting safe airport surface operations

Scipedia content — Thu, 28 Jan 2021 21:24:42 +0100

The Next Generation Air Transportation System (NextGen) concept proposes many revolutionary operational concepts and technologies, such as display of traffic information and movements, airport moving maps (AMM), and proactive alerts of runway incursions and surface traffic conflicts, to deliver an overall increase in system capacity and safety. A piloted simulation study was conducted at the National Aeronautics and Space Administration (NASA) Langley Research Center to evaluate the ability to conduct safe and efficient airport surface operations while utilizing an AMM displaying traffic of various position accuracies as well as the effect of traffic position accuracy on airport conflict detection and resolution (CDR when indications or alerts were generated in these same scenarios, the incidences were averted.

Adaptive dynamic power management for hard real-time pipelined Multiprocessor Systems

Scipedia content — Thu, 28 Jan 2021 21:20:47 +0100

Energy efficiency is a critical design concern for embedded systems. Dynamic power management (DPM) schemes in Multiprocessor System on Chips (MPSoCs) has been wildly used to explore the idleness of processors and dynamically reduce the energy consumption by putting idle processors to low-power states. In this paper, we explore how to effectively apply dynamic power management in adaptive manner to reduce leakage power consumption for coarse-grained pipelined systems under hard real-time requirements. At each adaptive point, a system transformation is proposed to model the pipeline system with unfinished events as multi-stream system. By using extended pay-burst-only-once principle, the service curves for corresponding stream can be computed as a constraint for a minimal resource demand and energy minimization problem can be formulated with respect to the resource demands at each adaptive point. One light-weight heuristic, called balance workload scheme (BWS), is proposed in this paper to solve the minimization problem. Simulation results using real-life applications are presented to demonstrate the effectiveness of our approach.

Vehicle-Hardware-In-The-Loop system for ADAS prototyping and validation

Scipedia content — Thu, 28 Jan 2021 21:20:05 +0100

This paper introduces an innovative system easing prototyping and validation of Advanced Driver Assistance Systems (ADAS) for automotive applications. This system, based on a chassis-dynamometer and a multi-sensor simulation software, act as a virtual reality platform for intelligent vehicle. This system allows to test and validate complex ADAS systems under various simulated environmental conditions and scenario without the cost, complexity and hazard associated with test-drives. It can also be used early in the design process to test and validate the integration of multiple ADAS in a vehicle. This system is being used for the Virtual Testing applications in the DESERVE 1 project.

Wake vortex detection, prediction and decision support tools in SESAR program

Scipedia content — Thu, 28 Jan 2021 21:12:17 +0100

airports, surface operation on the runway is the limiting factor for the overall throughput; specifically the fixed and overly conservative ICAO wake turbulence separation minima. The wake turbulence hazardous flows can dissipate quicker because of decay due to air turbulence or be transported out of the way on oncoming traffic by cross-wind, yet wake turbulence separation minima do not take into account wind conditions. Indeed, for safety reasons, most airports assume a worst-case scenario and use conservative separations; the interval between aircraft taking off or landing therefore often amounts to several minutes. However, with the aid of accurate wind data and precise measurements of wake vortex by radar sensors, more efficient intervals can be set, particularly when weather conditions are stable. Depending on traffic volume, these adjustments can generate capacity gains, which have major commercial benefits. This paper presents the developments of a wake turbulence system supporting increased throughput as part of the European ATM research program SESAR. This wake turbulence system is designed to, punctually or permanently, reduce landing and departure wake turbulence separations, thus increasing the runway throughput in such a way that arrival demand peaks and departure delays are safety absorbed. This global objective is by deploying radar sensors to deliver real-time position and strength information of the wake vortices and to assess wind conditions including ambient air turbulence via Eddy Dissipation Rate (EDR). To further address the optimization of throughput, two extensions for the use of wake turbulence system are considered for the terminal area and the runway rollout. These extensions connect the ground system with the aircraft to maximize benefits. The first application is the optimization of aircraft sequence via point-merge procedure, which is part of interval management operational improvement. The second application relates to the optimization of runway exit based on assessment of runway condition and aircraft-based braking capability to select the best runway exit for both the aircraft objectives and the runway throughput.

Study on Traffic Management Countermeasures Based on Road Network Capacity

Scipedia content — Thu, 28 Jan 2021 21:11:12 +0100

Urban traffic is a huge system, the key lies in the management of the normal operation of reasonable and effective measures. The choice of traffic management measures depends on traffic operation status of the overall. In quantitative analysis, network capacity is a characterization of the traffic state key index. In this paper, through the analysis of numerical calculation and capacity of road network, as a basis for determining the traffic management measures. At the same time, it takes Beidaihe district as the road network capacity calculation examples. Research background As a branch of management science, Traffic management is mainly in accordance with the actual situation of provisions of national laws, policies, regulations and road traffic, using various means, methods, tools, facilities, scientific and reasonable management measures. Due to the traffic environment is a complex system, the research methods can be divided to the quantitative analysis and qualitative analysis. Between them, quantitative analysis can objectively grasp the actual state of traffic operation, which is the most clear to object, the most intuitive to proceed, the most reliable to result. In quantitative analysis, network capacity is the key index for the traffic operation.

Advancements in the Detection and Sizing of “Pinhole” Metal Loss

Scipedia content — Thu, 28 Jan 2021 21:09:37 +0100

At IPC 2010 PII Pipeline Solutions (PII) presented the paper “VALIDATION OF LATEST GENERATION MFL IN-LINE INSPECTION TECHNOLOGY LEADS TO IMPROVED DETECTION AND SIZING SPECIFICATION FOR PINHOLES, PITTING, AXIAL GROOVING AND AXIAL SLOTTING”1, IPC 2010-31124. The suggestion was that this improvement would allow operators to make more informed pipeline integrity decisions in future."/jats:p" "jats:p"In the 4 years since this paper was presented many hundreds of runs have been completed with this latest generation MFL ILI technology, capturing information on tens of thousands of kilometers of pipe, and generating a significant volume of dig verification data. In collaboration with Oil & Gas pipeline operators around the world this growing dig verification database has been utilized to improve software models, algorithms, & analysis processes to validate and further enhance system detection, sizing, & reporting capabilities."/jats:p" "jats:p"This paper focuses on the recent collaboration between ExxonMobil and PII, to investigate system capabilities with respect to “Pinholes”, to address a known threat to a specific pipeline in the United Kingdom. This paper will describe the:"/jats:p" "jats:p"• Evolution of the “Pinhole” specification that captured the interest of ExxonMobil."/jats:p" "jats:p"• Use of Finite Element models to predict entitlement for characterization of “Pinhole” type defects"/jats:p" "jats:p"• Detail of and results from the ExxonMobil sponsored test program that was conducted in early 2013"/jats:p" "jats:p"• The in-line inspection, analysis report, and dig verification that followed for the pipeline in question."/jats:p" "jats:p"This joint paper, prepared and presented in collaboration by ExxonMobil & PII, will reflect the perspective and synergy of the Pipeline Owner/Operator and the ILI Vendor.

Vision on Wheels: Looking at Driver, Vehicle, and Surround for On-Road Maneuver Analysis

Scipedia content — Thu, 28 Jan 2021 21:02:28 +0100

utomotive systems provide a unique opportunity for mobile vision technologies to improve road safety by understanding and monitoring the driver. In this work, we propose a real-time framework for early detection of driver maneuvers. The implications of this study would allow for better behavior prediction, and therefore the development of more efficient advanced driver assistance and warning systems. Cues are extracted from an array of sensors observing the driver (head, hand, and foot), the environment (lane and surrounding vehicles), and the ego-vehicle state (speed, steering angle, etc.). Evaluation is performed on a real-world dataset with overtaking maneuvers, showing promising results. In order to gain better insight into the processes that characterize driver behavior, temporally discriminative cues are studied and visualized.

Impact of virtual bridging on virtual machine placement in data center networking

Scipedia content — Thu, 28 Jan 2021 20:51:26 +0100

International audience; The increasing adoption of virtualization techniques has recently favored the emergence of useful switching functions at the hypervisor level, commonly referred to as virtual bridging. In the context of data center network (DCN) consolidations, for VMs colocated in the same virtualization server, virtual bridging becomes very useful to offload inter-VM traffic from access and aggregation switches, at the expense of an additional computing load. DCN consolidations typically chase traffic engineering (TE) and energy efficiency (EE) objectives, and both should be affected by virtual bridging, but it is not intuitive to assert whether virtual bridging acts positively or negatively with respect to TE and EE that should also depend on the DCN topology and forwarding techniques. In this paper, we bring additional understanding about the impact of virtual bridging on DCN consolidations. First, we present a repeated matching heuristic for the generic multi-objective DCN optimization problem, with possible multipath and virtual bridging capabilities, accounting for both TE and EE objectives. Second, we assess the impact of virtual bridging on TE and EE in DCN consolidations. Extensive simulations show us that enabling virtual bridging has a negative impact when EE is the goal and multipath forwarding is adopted, while it leads to important gains, halving the maximum link utilization, when TE is the DCN consolidation goal. I. INTRODUCTION The recent achievement of x86 virtualization by advanced software techniques allows attaining virtualization of server and network functions at competitive performance-cost trade-offs with respect to legacy solutions. The increasing adoption of virtualization techniques has recently favored the emergence of useful switching functions at the hypervisor level, commonly referred to as virtual bridging. In the context of data center network (DCN) consolidations, for VMs colocated in the same virtualization server, virtual bridging becomes very useful to offload inter-VM traffic from access and aggregation switches, at the expense of an additional computing load on the physical server. DCN consolidations typically chase traffic engineering (TE) and energy efficiency (EE) objectives, and both should be affected by virtual bridging, but it is not intuitive to assert whether virtual bridging acts positively or negatively with respect to TE and EE that should also depend on the DCN topology and forwarding techniques. In this paper, we bring additional understanding about the impact of virtual bridging on DCN consolidations. The literature on DCN consolidation problems is extensive. Often referred to as DCN optimization, VM placement or virtual network embedding, the various propositions at the state of the art often have a narrow scope, with a set of constraints so that it is not possible to jointly adopt EE

NDNFlow: Software-defined Named Data Networking

Scipedia content — Thu, 28 Jan 2021 20:50:29 +0100

In this paper, we introduce NDNFlow: an open-source software implementation of a Named Data Networking based forwarding scheme in OpenFlow-controlled Software-Defined Networks (SDNs). By setting up an application-specific communication channel and controller layer parallel to the application agnostic OpenFlow protocol, we obtain a mechanism to deploy specific optimizations into a network without requiring a full network upgrade or OpenFlow protocol change. Our open-source software implementation consists of both an NDN-specific controller module and an NDN client plug-in. NDNFlow allows OpenFlow networks with NDN capabilities to exploit the benefits of NDN, by enabling the use of intermediate caches, identifying flows of content and eventually performing traffic engineering based on these principles.

Battery Capacity Estimation and Health Management of an Electric Vehicle Fleet

Scipedia content — Thu, 28 Jan 2021 20:41:30 +0100

International audience; This paper addresses the challenge of monitoring battery in fleets of electric vehicles (EV). The goal is to identify the different EV utilization modes, during real use, and to highlight the constraining conditions to manage battery health evolution. The other part of this study aims to build a battery capacity estimation model, permitting to estimate the remaining capacity of an EV during its real use. Finally, is explained a strategy to improve capacity estimates, based on the identified EV utilization modes.

Automatic 3D Reconstruction of As-built Pipeline Based on Curvature Computations from Laser-Scanned Data

Scipedia content — Thu, 28 Jan 2021 20:35:25 +0100

Demand has been growing for three-dimensional (3D) reconstruction of asbuilt pipelines that occupy large areas within operating plants. In practice, measurements are efficiently performed using laser-scanning technology; however reconstructing an as-built pipeline from this laser-scanned data remains challenging. The data acquired from the plant facility can be incomplete due to complex occlusion, or it can be affected by noise due to the reflective surfaces of the pipelines and other parts. The aim of this study is to propose a method for generating models of entire pipelines that include straight pipes, elbows, reducers, and tee pipes from laserscanned data. The proposed 3D reconstruction method for as-built pipelines is divided into three main tasks: (1) identifying the types and locations of the pipelines from the laser-scanned data; (2) segmenting the pipelines into each type of pipe form; and (3) reconstructing the pipelines’ geometry and topology and generating models of them. Field experiments were performed at an operating industrial plant in order to validate the proposed method. The results revealed that the proposed method can indeed contribute to the automation of 3D reconstruction of as-built pipelines.

Can High Speed Rail foster the choice of destination for tourism purpose?

Scipedia content — Thu, 28 Jan 2021 20:15:51 +0100

International audience; Marketing decisions and strategic planning of tourism provisions require knowledge of factors affecting this choice and type of trips and forecast of tourism flows in the short and long term. It is interesting to know how holidaymakers select their holiday destinations and investigate which factors are determining their choices. Indeed the objective of this paper is to analyze the role of High Speed Rail systems in this choice. A survey was carried out in Paris in October 2012, tourists were interviewed close to the Eiffel Tower, Paris Lyon Central Train Station and Notre-Dame Cathedral. The results will be compared with a previous survey employed in Rome in April 2012. The scope here is providing an answer to the questions: are tourists influenced by the presence of High Speed Rail in choosing Paris or Rome for their holidays? Does High Speed Rail influence the probability of visiting other served cities and returning to Paris or to Rome? The research suggests that several factors (the presence of architectural sites, the quality of promotion of the destination itself, the presence of events) influence the choice of a tourist. It also shows that the HSR system has affected the choice of Paris and Rome differently.

From Scripted HPC-Based NGS Pipelines to Workflows on the Cloud

Scipedia content — Thu, 28 Jan 2021 20:14:15 +0100

In this paper we describe our initial experiences in the Cloud-e-Genome project with moving the whole exome sequencing pipeline from the scripted HPC-based solution to a workflow enactment system running in the cloud. We discuss shortcomings of the existing approach based on scripts and list benefits that a workflow-based solution can provide. Despite the effort it involved to wrap all required tools in the form of workflow blocks and the restrictions of the dataflow model used to represent workflows we expect the migration to significantly improve the current status of the pipeline. Our target is to enable flexibility, traceability and reproducibility of the solution, so that it can better fit the evolution of tools, data and pipeline itself and allow us to run it at national scale. This work will become foundation for the more complete system that includes variant filtering and interpretation for the diagnostic purposes.

Integrated Approach to Machine Guidance and OperationsMonitoring in Tunnel Construction

Scipedia content — Thu, 28 Jan 2021 20:01:47 +0100

Tunnel construction method using a tunnel boring machine (TBM) is commonly adopted for building underground infrastructure, such as railways, roads, sewers, or utility pipelines. TBM tunnelling entails precise guidance of the machine in the underground space, as well as effective construction management and project control. The research aims to address critical engineering and management problems during the course of tunnel excavation, including TBM guidance, automated asbuilt data acquisition, real-time data processing and 3D visualization. In this paper, we propose an integrated TBM guidance and operations monitoring solution for tunneling applications. A robotic total station is employed to automate the continuous processes of TBM tracking and guidance inside the tunnel. Wireless sensor networks are particularly implemented for on-site data communication. The results of TBM's position state, tunnel alignment and construction progress are processed and presented in straightforward, user-friendly interfaces on the fly. Working with the City of Edmonton, Alberta, Canada, the integrated system has been implemented in the construction of a 2.4-meterdiameter and 1-km-long sewage tunnel project and undergone seven-month field testing in 2013. The solution lends substantial support to TBM operators and project managers in making critical decisions on a near real-time basis.

The Irkutsk Transportation Master Plan solutions for public transport system development

Scipedia content — Thu, 28 Jan 2021 19:52:50 +0100

Irkutsk has extremely favourable conditions for developing the electric public transportation system. The basis of the regional power system is the Irkutsk hydropower station. It has a unique feature; the stability of seasonal power production throughout the year. Due to this factor, the cost of power production in Irkutsk is one of the lowest in the world. The master plan for Irkutsk was created in 1985 and was intended as a means to further the development of the tram network. However, ten years later, the tramline was excluded from the technical project of the new bridge across Angara River. As a result, private bus companies received the most lucrative segment of the public transport system and the municipal network of electric public transport became ineffective and received a negative economic balance. In 2008–2010 the transportation laboratory of Irkutsk State Technical University (TL ISTU) created the Transportation Master Plan for Irkutsk. The goal of this project was to forecast traffic and passenger flow distribution up to 2020. According to TL ISTU forecasts, the largest daily passenger and traffic flows are between the Sverdlovsky borough and the city center. TL ISTU has modelled several combinations of routes for the public transport system, including the consideration of a new bridge over the Angara River and arguing for the municipal trolleybus network development.

A Hole in Your Pocket; Mitigating Corrosion Perforations of Well Casings in Corrosive Formations with Advanced Technology Epoxies

Scipedia content — Thu, 28 Jan 2021 19:51:00 +0100

!!paper is an overview of coated and non-coated well casings in corrosive formations. Failure trend studies of externally un-coated well casings indicate a prevalence of external casing failures due to corrosive formations. Some casing failures have been documented in as little as twenty-four months. Well casings coated with advanced technology epoxies have improved the service life of these wells significantly. This paper describes the key learnings from these applications. ! Current successes in hydraulic fracturing techniques have lead to an extraordinary increase in drilling activity around the world. This recent boom in drilling activity has caught the attention of the general public and government regulators alike. One concern of particular interest is the use and protection of fresh water resources. Modern completion techniques require large amounts of fresh water to fracture hydrocarbon producing zones. There is also growing concern from the general public about completion chemicals and production fluids potentially contaminating freshwater sources. Maintaining casing integrity is essential to oil and gas production as well as protecting freshwater zones. Historically, Operators have employed several methods to isolate wellbores and production fluids from freshwater zones. Many of these protection methods have been used with differing amounts of success depending on casing design and metallurgy, cementing practices, wellbore geology and numerous other factors. One isolation method that is often overlooked is protective coatings for the externals of well casing. !coatings have commonly been used in the Oil & Gas industry for decades as the first line of defense against corrosion. Coatings are known to be an effective and economically efficient method for protecting metal structures against the effects of corrosive environments. They are used on everything from the rig floor to pipelines and just about everything in between. Why is it then, that we overlook protective coatings as a corrosion control method for well casing? Well casing is often exposed to the following corrosive conditions: ! ∞ Microbiologically-Influenced Corrosion (MIC)

A Generic System Architecture for Energetic Optimization of Vehicles by Using Driver Assistance Systems

Scipedia content — Thu, 28 Jan 2021 19:41:48 +0100

The increase of energy efficiency of vehicles in the course of rising energy costs and the limited range of electric vehicles can be realized with ecological driver assistance systems. Based on preview information these systems can assist the driver in providing energy efficient driving and operating strategies. But, many of these systems directly focus on specific functional approaches and do not consider a comprehensive system architecture. Thus, functional extensions and adoptions to other vehicle and propulsion concepts are hereby complicated."/jats:p" "jats:p"In this paper a generic system architecture is introduced which represents a framework for present and future for assistance systems for ecological optimization. The framework provides hereby the overview of the necessary core modules and the interfaces between them. The innovative aspect of the introduced framework is the modularization in a vehicle independent optimization module and a vehicle dependent energy conversion model. This approach promotes a vehicle independent and efficient system development. The system architecture aims to provide a basis for assistance systems that are robust towards functional extensions and adoptions to other vehicle and propulsion concepts."/jats:p" "jats:p"In an exemplary use case the application of the generic system architecture is demonstrated and the portability is discussed.

Structural Performance of Buried Steel Pipelines Crossing Strike-Slip Faults

Scipedia content — Thu, 28 Jan 2021 19:35:08 +0100

The performance of pipelines subjected to permanent strike-slip fault movement is investigated by combining detailed numerical simulations and closed-form solutions. A closed-form solution for the force-displacement relationship of a buried pipeline subjected to tension is presented and used in the form of nonlinear springs at the two ends of the pipeline in a refined finite element model, allowing an efficient nonlinear analysis of the pipe-soil system at large strike-slip fault movements. The analysis accounts for large deformations, inelastic material behaviour of the pipeline and the surrounding soil, as well as contact and friction conditions on the soil-pipe interface. Appropriate performance criteria of the steel pipeline are adopted and monitored throughout the analysis. It is shown that the end conditions of the pipeline have a significant influence on pipeline performance. For a strike-slip fault normal to the pipeline axis, local buckling occurs at relatively small fault displacements. As the angle between the fault normal and the pipeline axis increases, local buckling can be avoided due to longitudinal stretching, but the pipeline may fail due to excessive axial tensile strains or cross sectional flattening.

The effectiveness of using viscoelastic materials to reduce seismic induced vibrations of above ground pipelines

Scipedia content — Thu, 28 Jan 2021 19:33:36 +0100

Pipeline systems are commonly used to transport oil, natural gas, water, sewage and other materials. They are normally regarded as important lifeline structures. Ensuring the safety of these pipeline systems is crucial to the economy and environment. There are many reasons that may result in the damages to pipelines and these damages are often associated with pipeline vibrations. Therefore it is important to control pipeline vibrations to reduce the possibility of catastrophic damages. This paper carries out numerical investigations on the effectiveness of using viscoelastic material layers to mitigate seismic induced vibrations of above ground pipelines. The numerical analyses are carried out by using the commercial finite element code ANSYS. The numerical model of the viscoelastic material is firstly calibrated based on the experimental data obtained from a 1.6m long tubular sandwich structure. The calibrated material model is then applied to the pipeline system. The effectiveness of using viscoelastic materials as the seismic vibration control solution is discussed.

Pedestrian path prediction using body language traits

Scipedia content — Thu, 28 Jan 2021 19:24:51 +0100

Driver Assistance Systems have achieved a high level of maturity in the latest years. As an example of that, sophisticated pedestrian protection systems are already available in a number of commercial vehicles from several OEMs. However, accurate pedestrian path prediction is needed in order to go a step further in terms of safety and reliability, since it can make the difference between effective and non-effective intervention. In this paper, we consider the three-dimensional pedestrian body language in order to perform path prediction in a probabilistic framework. For this purpose, the different body parts and joints are detected using stereo vision. We propose the use of GPDM (Gaussian Process Dynamical Models) for reducing the high dimensionality of the input feature vector (composed by joints and displacement vectors) in the 3D pose space and for learning the pedestrian dynamics in a latent space. Experimental results show that accurate path prediction can be achieved at a time horizon of ≈ 0.8 s.

A hybrid algorithm for planning public charging stations

Scipedia content — Thu, 28 Jan 2021 19:23:43 +0100

International audience; Green mobility solutions are receiving currently an enormous attention. Indeed, during last years, electric vehicles, being part of the field of the smart-grid, entered the automobile market of the whole world. This technology requires an effective deployment of charging stations of electric refill since the main problem in this system remains over the duration of refill of the batteries. In this work, we propose an optimized algorithm to locate electric charging stations. The main task of the algorithm is to find the best site of charging stations locations so as to minimize loss on the way to the charging station, as well as minimize investment cost, we take into account several constraints to find the optimal number and placement of charging station. Our hybrid algorithm with improved K-means clustering and genetic algorithm can be used to find optimal number and place of charging stations.

Retrofit solutions for inland ships: The MoVe IT! approach

Scipedia content — Thu, 28 Jan 2021 19:18:17 +0100

In MoVe IT!, a project in the European 7th framework package, it is investigated how existing European inland cargo ships can be retrofitted in order to improve their economic and environmental performance. In the project, experts from academia worked closely together with five ship owners to identify the most promising retrofit options for one of their ships and to elaborate them. In this paper, the MoVe IT! approach is discussed, as well as some key results. After a brief introduction to the project, an overview of all identified retrofit options is presented, followed by the selection of the options that were deemed most desirable. As an example of the MoVe IT! solutions, the elaborated hydrodynamic retrofit options for the coupled unit MS Herso I and barge Leonie are discussed in detail, followed by a short overview of the results of retrofit attempts for all ships surveyed within MoVe IT!. The paper is concluded with the most important lessons that were learned from the efforts to find good retrofit solutions for inland ships.

Sevilla: a successful experience of bicycle promotion in a Mediterranean context

Scipedia content — Thu, 28 Jan 2021 19:15:05 +0100

From 2006 to 2011 Sevilla experienced a rapid growth in urban cycling, from a negligible participation in the modal split up to 9% of the total mechanical trips. This rapid growth was based on some active policies heavily based on the building of a continuous and homogeneous network of segregated cycle paths. In this paper the authors analyse the main guidelines for the development of this infrastructure, as well as its impact on urban mobility and bicycle traffic safety. The authors found that the risk of cycling was reduced in parallel to the increase in the number of cyclists, in agreement with the safety in numbers hypothesis. Future trends for further improving bike mobility are also described and analysed. Finally, the authors make an estimation of the possible effects on bicycle use of a hypothetical compulsory helmet regulation, a possibility that is presently under debate in Spain.

Optimizing Buffer Sizes for Pipeline Workflow Scheduling with Setup Times

Scipedia content — Thu, 28 Jan 2021 19:07:02 +0100

Mapping linear workflow applications onto a set of homogeneous processors can be optimally solved in polynomial time for the throughput objective with fewer processors than stages. This result even holds true, when setup times occur in the execution and homogeneous buffers are available for the storage of intermediate results. In this kind of applications, several computation stages are interconnected as a linear application graph, and each stage holds a buffer of limited size where intermediate results are stored and a processor setup time occurs when passing from one stage to another. In this paper, we tackle the problem where the buffer sizes are not given beforehand and have to be fixed before the execution to maximize the throughput within each processor. The goal of this work is to minimize the cost induced by the setup times allocating buffers with proportional sizes of each other. We present a closed formula to compute the optimal buffer allocation in the case of non-decreasing setup costs in the linear application. For the case of unsorted setup times, we provide competitive heuristics that are validated via extensive simulation.

Empirical analysis of lane changing behavior at a freeway weaving section

Scipedia content — Thu, 28 Jan 2021 18:58:22 +0100

TRB 2014 - Transportation Research Board 93rd Annual Meeting, WASHINGTON D.C, ETATS-UNIS, 12-/01/2014 - 16/01/2014; An empirical analysis is conducted on lane changing behavior using a trajectory data set collected at a weaving section in Grenoble (France). A detailed literature review shows that strong empirical understanding of the weaving mechanisms is still lacking. The goal is to investigate the lane changing behavior at a microscopic level. Data collection distinguished lane changes from the main road and those towards the main road. Descriptive empirical analysis examines the positions of the lane changes and the corresponding accepted gaps. Results show that under heavy congested traffic conditions the weaving vehicles tend to change lane as soon as possible after the start of the weaving section. When the traffic conditions are fluid, the weaving vehicles coming from the main road tend to change lane earlier than the weaving vehicles coming from the auxiliary lane. Moreover, weaving vehicles coming from the auxiliary lane accept smaller gaps and headways than the weaving vehicles coming from the main road. Our findings are questioning some results of previous works using micro-simulation to study weaving sections. As the weaving vehicles change lane at the beginning of the studied weaving section, our findings ask whether the length of the weaving section is a key variable to estimate its capacity. Our findings raise also some questions about the relevance of the gap acceptance theory to model lane changes at weaving sections. But further research are needed to asses these hypothesis.

An agent-based approach to automated merge 4D arrival trajectories in busy terminal maneuvering area

Scipedia content — Thu, 28 Jan 2021 18:56:09 +0100

This paper presents a new approach for automated merging multiple aircraft flows in a busy Terminal Maneuvering Area (TMA). This work is motivated by the current overloaded airspace in the Beijing Capital international airport, the highlighted delay in the China air transportation and the need of more efficient methods to help air traffic controllers. Present research consists of a new approach to optimize a set of aircraft planned to land at a given airport based on multi-agents technique, which is automated generating comprehensive sequencing plan and conflicts-free trajectories.The architecture of the system is based on a Point Merge (PM) route structure to enable expediting or delaying aircraft while staying on lateral navigation mode.The whole system is designed by two main models to manage the process of arriving flows: Sequencing leg and Link. And then, 4 kinds of agents are designed to support the implementation of this automated system: aircraft agent, flow manager agent, conflict detection and resolution agent and 4D trajectory planning agent. We consider the 4D trajectory-based operation situation in TMA and apply different wake turbulence constraint in these two models. Finally, aconclusion is made and future work is outlined. Refereed/Peer-reviewed

How to address the chicken-egg-problem of electric vehicles? Introducing an interaction market diffusion model for EVs and charging infrastructure

Scipedia content — Thu, 28 Jan 2021 18:54:37 +0100

native fuel vehicles (AFVs) face the lack of refuelling infrastructure as one obstacle to initial market diffusion. Also potential operators of refuelling stations await significant market shares before constructing a dense refuelling network. The resulting lock-in effect or chicken-egg-problem has been a field of research for many AFVs, but the co-diffusion of PEVs has rarely been analysed for plug-in electric vehicles (PEVs) up to now.1 This might derive from the large availability of private charging options (simple sockets at home) or semi-public charging options (at work). The question is whether these charging options are sufficient to overcome the potential lock-in or how much additional public charging infrastructure is needed. Here, we develop an agent-based market diffusion model for PEVs and their charging infrastructure that is based on a large number of individual driving profiles for private and commercial car holders in Germany. Within the model, we determine the utility-maximising fuel type for each user based on cost, willingness-to-pay and the available charging infrastructure which derives from its driving behaviour and socio-demographic information. Infrastructure agents build public charging points when economically sensible. Our results show that there can be a market evolution in Germany without any public charging infrastructure facilities, since many vehicles are parked in garages or close to a house where power outlets are already available or easy to install. The second-best option for an infrastructure set-up is at work where the majority of vehicles is parked over a long time during the day, the installation is not costly and users profit more than from public facilities. Public charging facilities can increase PEV market shares, but they need to be subsidised for a long time.

Measuring control plane latency in SDN-enabled switches

Scipedia content — Thu, 28 Jan 2021 18:49:38 +0100

Timely interaction between an SDN controller and switches is crucial to many SDN applications---e.g., fast rerouting during link failure and fine-grained traffic engineering in data centers. However, it is not well understood how the control plane in SDN switches impacts these applications. To this end, we conduct a comprehensive measurement study using four types of production SDN switches. Our measurements show that control actions, such as rule installation, have surprisingly high latency, due to both software implementation inefficiencies and fundamental traits of switch hardware.

Using Urban Modelling and Geographical Analyses to Tackle Emergent Urban Logistics Issues: Developing a Decision-making Tool for Urban Goods Distribution

Scipedia content — Thu, 28 Jan 2021 18:49:15 +0100

For the most part, urban goods transportation is neglected by urban studies and urban planning, as opposed to urban passenger transportation. This article will present outcomes of a research project whose goal is to develop an efficient decision-making tool for urban logistics from a spatial and territorial perspective, based on urban modelling and geographical analyses. The hypothesis of this research project is that understanding urban freight through spatial structures will contribute to improving territorial diagnosis, which is essential to the understanding of urban goods distribution issues before any decision can be made and will result in specific and efficient last-mile delivery solutions. This article will describe the methodology of the decision-making tool, and discuss its limitations, inputs and perspectives.

Generating rich trip data using smartphone applications to facilitate feasibility studies for bicycle sharing schemes

Scipedia content — Thu, 28 Jan 2021 18:47:20 +0100

eer-reviewed Limerick was designated as Ireland’s National Smarter Travel demonstration area in 2012. Limerick Smarter Travel, which aims to promote sustainable travel in the City and suburbs, is a partnership between the Limerick Councils and the University of Limerick (UL). Within UL, final-year projects and other research is on-going in the smarter travel subject area. This paper is based on Limerick City’s Bike Sharing Scheme and a final-year project thesis which is a study of the feasibility of a stand-alone bike sharing scheme in the suburb of Castletroy adjacent to the University of Limerick. This paper also focused on discovering if it would be feasible to merge a Castletroy scheme with the existing Limerick city scheme or extend the existing city scheme to the Castletroy area. The paper details the use of a smartphone application to collect rich trip and mode share data and proposes this methodology as a significant improvement on current feasibility study methods for bike sharing scheme feasibility studies. The smartphone application is capable of collecting numerous persons travel data for the entire period of the day. Data such as distance travelled, mode of travel, time taken to travel and trip destination and origin are all collected within the application. From this data, heat maps were produced for each of the survey participants. An example of a heat map for one candidate can be seen in Figure 3.6. In these heat maps, dark purple lines highlight routes of low activity, where bright orange lines highlight routes of high activity for that user for the specified study period. A number of precedent studies were also investigated as well as generating, collecting, analysing and investigating a number of quantitative datasets. The quantitative datasets explored include: travel survey results for University of Limerick students and staff; Places of Work – Census of Anonymised Records data for Castletroy residents; secondary data gathered through an online survey and primary data gathered using the implementation of the GPS smartphone application to monitor the travel patterns of eighteen candidates. Recommendations for further research are also outlined in the paper.

Extended Range Guidance System for the Teleoperation of Microtunnelling Machines

Scipedia content — Thu, 28 Jan 2021 18:42:23 +0100

Microtunneling is a trenchless construction method that is highly adequate to install pipelines beneath roads, rail roads, dams, harbours and environmentally sensitive areas. Microtunneling could be understood as a remotely-controlled, guidance operation of a MicroTunneling Boring Machine (MTBM), where references are provided by a human operator from the surface. A review of current technologies and main working principles of traditional guidance systems used to determine the position and orientation of the drill head of the MTBM during tunneling will be presented. Practical limitations and drawbacks will be discussed. A special attention will be given to those systems based on a laser-generated reference. In this paper a new video target system developed to improve the current performance of guidance systems will be presented. As it will be detailed, improving target processing of laser’ incidence allow us to extend the minimum range to achieve a distance over 400 m, without having to displace the total reference stations which are guiding the path during tunnel execution. The new target sensing principle, the implementation approach, the image processing and pose estimation algorithms will be discussed. Additionally, some preliminary results of the prototype in its current testing phase in real scenarios, gathered in parallel with commercial units, and its comparison will be presented.

An interval based representation of occupancy information for driver assistance systems

Scipedia content — Thu, 28 Jan 2021 18:35:59 +0100

Future Advanced Driver Assistance Systems (ADAS) require detailed information about occupancy states in the vehicle's local environment. In contrast to widespread occupancy grids, this information should be represented in a compact, scalable and easy-to-interpret data structure. In this paper, we show how occupancy probabilities can efficiently be represented in our 2D Interval Map framework. The basic idea of this approach is to discretize the vehicle's environment only in longitudinal direction and to avoid quantization errors in lateral direction by storing continuous values. In order to correctly deal with dynamic obstacles in ADAS scenarios, the map also interacts with a model based object tracking. The comparison of our experimental results to a ground truth illustrates the differences of grid and interval based environment representations. A tested collision avoidance function yields similar results for both representations, while computation times and memory requirements are substantially improved by the application of the 2D Interval Map.

Assessment of plug-in natural gas versus electric vehicles on the Groningen energy network

Scipedia content — Thu, 28 Jan 2021 18:29:03 +0100

This study aims to evaluate the effect in the energy network of a big shared of decarbonise vehicles (NGV and EV) based on car-use profiles of current conventional and electric vehicles in the city of Groningen. Charging profiles were developed within CBS dataset of mobility and transport, and the electric charging profiles provided by E-Laad.

The effective use of excess capacity for low carbon urban transport futures

Scipedia content — Thu, 28 Jan 2021 18:27:07 +0100

reduction in emissions from transport is essential and requires a system wide approach, inclusive of technological and behavioural changes. Defining capacity in urban transport as the space through which transport demand can be met, the research explores where there is excess capacity in the system and how this could be used to reduce emissions. Capacity may be physical capacity in the roadspace or seats within vehicles, or temporal capacity, where there are fluctuations in the use of the system, such as peak and off-peak flows. This is complementary to the International Energy Agency (IEA)’s definition of urban transport energy efficiency as maximising travel activity whilst minimising energy consumption through a range of approaches and techniques. This paper proposes that interventions designed to enable behavioural change could reduce emissions by changing the way that the urban transport system is used. Drawing on the literature, this work demonstrates how effective use of excess capacity might be facilitated through measures such as smarter choices programmes and the application of intelligent transport systems (ITS). Case studies are provided as examples of ways that urban transport infrastructure can be adapted for more efficient use, including shared space projects and the ‘complete streets’ policy in New York City. The paper concludes by presenting the potential impacts of effective use of excess capacity for reducing urban transport emissions as demonstrated through the case studies.

Development of miles-in-trail passback restrictions for air traffic management

Scipedia content — Thu, 28 Jan 2021 18:26:21 +0100

This paper presents modeling of miles-in-trail passback restrictions for use in air traffic management. Generally, FAA managers employ miles-in-trail as a traffic management initiative when downstream traffic congestion at airports or in sectors is anticipated. In order to successfully implement the miles-in-trail at airspace fixes or navigational aids, it is desired that restriction values be computed for passing back to upstream facilities at specific boundaries. This paper presents a model which can be used for that purpose. This model improves on a previous version using traffic manager feedback resulting in significant improvement in guidance. The modeling approach is described along with lessons learned and improvements made during model development. Results for two sample traffic and one real traffic scenarios are presented. Additional operational considerations required by the traffic managers to implement the passback restrictions, namely maximum ground delay and absorbable airborne delay are incorporated in the model. A main result of this research is that absorbing small amount of ground and airborne delays are sufficient to handle the imposed constraint. Another finding is that implementing the passback restrictions provides the traffic managers ways to alleviate traffic constraints to help reduce excessive airborne delay for current traffic conditions.

Mass estimation for an adaptive trajectory predictor using optimal control

Scipedia content — Thu, 28 Jan 2021 18:16:25 +0100

traffic predictability is paramount in the air traffc system in order to enable concepts such as Trajectory Based Operations (TBO) and higher automation levels for self-separation. Whereas in simulated environments 4D conflict-free trajectory optimisation has shown good potential in the improvement of air traffc effciency, its application to real operations has been very challenging due to the current lack of information sharing between airspace users. Consequently, such operations are still very limited in scope and rarely attempted in dense traffic situations. Better predictability of other traffc future states would be an enabler for each aircraft to fly its user preferred route without decreasing safety in a self-separation context. But this is not an easy task when basic aircraft parameters such as aircraft weight, performance data or airline strategies are not available at the time of prediction. In this paper the authors propose to compensate this hindrance by continuously integrating the state of the surounding traffc to improve the ownship's knowledge of other aircraft's dynamics. Specifically, conventional position (and velocity) messages, as coming from Automatic Dependent Surveillance Broadcast (ADS-B), are integrated at the ownship. Then, an optimisation problem is formulated, using optimal control theory, that minimises the error with the known states, having the parameters of study (i.e. mass) as decision variables. A scenario with two departing trajectories is used to demonstrate the e ectiveness of this parameter estimation method. In it, the take-off mass of the potential intruder is estimated on- board the ownship and its impact to conflict detection and resolution is presented, demonstrating the big improvements in predictability and safety.

Peer Reviewed

Document type: Conference object

Traffic engineering with elastic traffic

Scipedia content — Thu, 28 Jan 2021 18:14:59 +0100

In the network layer, an internet service provider controls the traffic across an autonomous system by load balancing via traffic engineering and by varying the offered traffic of the users via feedback signals. In the transport layer, users send traffic into the network using the TCP protocol, which adjusts offered traffic according to the received feedback. We investigate how feedback and current traffic engineering practice interact with congestion control under the network utility maximization framework. We show that the current interaction is stable, increases network utility, but does not necessarily improve the traffic engineering objective. The mismatch in outcome and incentives prompt us for a more holistic view using game theory. With suitable modification of the feedback, we show that the interaction converges to a socially optimal solution for users running either primal or dual algorithms. We further show that the results hold even when traffic engineering is performed at any irregular intervals. More generally, we show via heterogeneous feedback the same optimality result for a mix of users running primal and dual algorithms.

Predicting multimedia traffic in wireless networks: A performance evaluation of cognitive techniques

Scipedia content — Thu, 28 Jan 2021 18:14:48 +0100

Traffic engineering in networking is defined as the process that incorporates sophisticated methods in order to ensure optimization and high network performance. One of the most constructive tools employed by the traffic engineering concept is the traffic prediction. Having in mind the heterogeneous traffic patterns originated by various modern services and network platforms, the need of a robust, cognitive, and error-free prediction technique becomes even more pressing. This work focuses on the prediction concept as an autonomous, functional, and efficient process, where multiple cutting-edge methods are presented, modeled, and thoroughly assessed. To this purpose, real traffic traces have been captured, including multiple multimedia traffic flows, so as to comparatively assess widely used methods in terms of accuracy.

The influence of the European CiViTAS ELAN project on development of a better and sustainable public transport in the City of Zagreb

Scipedia content — Thu, 28 Jan 2021 18:13:30 +0100

The CiViTAS Initiative is the EU response to the growing problems caused by traffic in European urban centres such as traffic congestion, noise, exhaust gases and difficult access to the city centre. The CiViTAS Initiative helps cities to test and develop an integrated set of measures for sustainable urban mobility. One of the projects is CiViTAS ELAN where five cities Ljubljana, Gent, Zagreb, Brno and Porto are cooperating. The goal of this project is to improve the quality of life for citizens and to implement better solutions in urban transport by promoting and enhancing sustainable, clean and energy efficient ways of transport. It is funded by the FP7 Programme and total duration of the project is 48 months from 2008 to 2012. As a part of CiViTAS ELAN, the City of Zagreb wants to discourage the use of cars by making public transport and cycling as a more attractive alternative. CiViTAS highlights in Zagreb are: decrease of traffic congestion, improvement of quality, accessibility and attractiveness of public transport, switch to cleaner modes of public transport, lower environmental impact of city fleet, inclusion of the existing railway into the city’s public transport system, improvement of cycling conditions and introduction of alternative modes of transport and mobility i.e. car pooling. The paper will present some measures and their results after three years of project implementation such as decreased congestion in pilot corridor along Savska street, decreased energy consumption and noise, improved public transport quality by purchasing 70 energy efficiency trams and 160 buses on gas or bio-diesel, e-ticketing, inter-modal solutions, etc.

A new performance measure and evaluation benchmark for road detection algorithms

Scipedia content — Thu, 28 Jan 2021 18:09:53 +0100

Detecting the road area and ego-lane ahead of a vehicle is central to modern driver assistance systems. While lane-detection on well-marked roads is already available in modern vehicles, finding the boundaries of unmarked or weakly marked roads and lanes as they appear in inner-city and rural environments remains an unsolved problem due to the high variability in scene layout and illumination conditions, amongst others. While recent years have witnessed great interest in this subject, to date no commonly agreed upon benchmark exists, rendering a fair comparison amongst methods difficult. In this paper, we introduce a novel open-access dataset and benchmark for road area and ego-lane detection. Our dataset comprises 600 annotated training and test images of high variability from the KITTI autonomous driving project, capturing a broad spectrum of urban road scenes. For evaluation, we propose to use the 2D Bird's Eye View (BEV) space as vehicle control usually happens in this 2D world, requiring detection results to be represented in this very same space. Furthermore, we propose a novel, behavior-based metric which judges the utility of the extracted ego-lane area for driver assistance applications by fitting a driving corridor to the road detection results in the BEV. We believe this to be important for a meaningful evaluation as pixel-level performance is of limited value for vehicle control. State-of-the-art road detection algorithms are used to demonstrate results using classical pixel-level metrics in perspective and BEV space as well as the novel behavior-based performance measure. All data and annotations are made publicly available on the KITTI online evaluation website in order to serve as a common benchmark for road terrain detection algorithms.

Cooperative ramp metering simulation

Scipedia content — Thu, 28 Jan 2021 18:08:14 +0100

The increase of vehicle numbers in recent decades resulted in road traffic congestion problems. Such congestions are a characteristic of densely populated urban areas and occur daily during morning and afternoon rush hours. Urban areas have been suffering from the lack of space needed to build new road infrastructure. The traffic congestion problem can be solved by applying new traffic control approaches from the domain of intelligent transportation systems (ITS). One of the applied methods from ITS is known as ramp metering and is used to increase the throughput of urban highways with many on- and off-ramps. Nowadays ramp metering is used in cooperation with additional control approaches like variable speed limit control (VSLC). Prior to implementation, such cooperative traffic control systems have to be tested in simulations using real world traffic data. One of the used simulators is CTMSIM which enables macroscopic simulation of highway traffic and local ramp metering approaches. In this paper the CTMSIM simulator is augmented to enable simulation of cooperative ramp metering algorithms, stand-alone VSLC, and cooperation between ramp metering and VSLC. Augmented simulator is tested using some limited available traffic data with the Zagreb bypass urban highway as a case study.

Air pollution generated by road traffic in the city of Zagreb and measures proposed

Scipedia content — Thu, 28 Jan 2021 18:02:09 +0100

The objective of this paper is to analyze the impact of road traffic on air pollution in the city of Zagreb and emphasise the measures to establish sustainable traffic in the city of Zagreb. Due to the large number of vehicles, high percentage of defective vehicles and relatively low speeds (below 80 km/h), the highest effect on air pollution in the city of Zagreb is generated by road vehicles. If air pollution in the city is analyzed from 2001 to 2009 it may be concluded that the biggest problem lies in the pollution by nitrogen oxides, airborne particles and ground-level, which means that taking these pollution parameters into consideration the air was of category II, i.e. moderately polluted. The most endangered city areas are the industrial zones and traffic nodes. Some of the suggestions for decreasing the emission of harmful components in exhaust gasses emissions in Zagreb are: reconstruction of road network (emphasis on intersection), introduction of traffic oriented control, usage of intelligent transport systems for guiding organization of traffic, “park and ride” system, fuel quality improvement etc. In the city of Zagreb there’s a lot of room for improvements in technical, technological and ecological sense. This paper in conclusion offers optimal proposals of measures to establish better air quality and sustainable traffic in the city of Zagreb.

A review of Turboelectric Distributed Propulsion technologies for N+3 aircraft electrical systems

Scipedia content — Thu, 28 Jan 2021 17:57:11 +0100

In order to minimise the environmental impact of increased air traffic substantial developments in civil aircraft electrical power systems must occur. NASA have set a target to reduce noise by 71dB, NOx emissions by 80% and fuel consumption by 60% for the N+3 generation of aircraft entering into service sometime between 2030 and 2035. Turboelectric Distributed Propulsion (TeDP) is expected to enable these goals to be met. NASA's N3-X concept aircraft comprises gas turbine engines which drive electrical generators and a DC network distributes power to an array of fans, which provide thrust. Interconnection and protection technologies will also be included to achieve desired levels of reliability of supply to the propulsion motors. This paper outlines the architecture of a generic TeDP system, explores its benefits, describes technical challenges that will need to be overcome and discusses the technical implications of implementing TeDP with regards to electrical system power density and safety.

A Matlab Implementation of Differential GPS for Low-cost GPS Receivers

Scipedia content — Thu, 28 Jan 2021 17:53:46 +0100

number of public codes exist for GPS (global positioning system) positioning and baseline determination in off-line mode. However, no software code exists for DGPS (differential GPS) exploiting correction factors at base stations, without relying on double difference information. In order to accomplish it, a methodology is introduced in MATLAB environment for DGPS using C/A (course acquisition) pseudoranges on single frequency L1 only to make it feasible for low-cost GPS receivers. The base station is at accurately surveyed reference point. Pseudoranges and geometric ranges are compared at base station to compute the correction factors. These correction factors are then handed over to rover for all valid satellites observed during an epoch. The rover takes it into account for its own true position determination for corresponding epoch. In order to validate the proposed algorithm, the rover is also placed at a pre-determined location. The proposed code is an appropriate and simple to use tool for post-processing of GPS raw data for accurate position determination of a rover e.g. Unmanned Aerial Vehicle during post-mission analysis.

Document type: Article

A SOAP-Based Social Traffic Network System for Smart Phone Users

Scipedia content — Thu, 28 Jan 2021 17:53:14 +0100

Road traffic congestions are one of the major problems in highly populated cities. In the recent years, GPS based solutions have become popular since people are able to see the traffic flow on streets instantaneously. However such systems are lack of intelligent reasoning regarding the traffic problems. As a result, one cannot anticipate the traffic slowdown duration and overall impact. This study proposes a social network based solution using web services where people will be able to share latest traffic incidents such as accidents and roadwork. The proposed solution aims to help people to make the right decisions between alternative routes. The prototype developed was evaluated in a survey among 182 smart phone users and the results show that the most of the participants (72%) reveal a very positive attitude towards the solution and accept it as a desirable tool as a remedy for daily traffic problems.

Conditioning TRANSPETRO’s Gas Pipeline Network to the Baía de Guanabara LNG Terminal New Regasification Profile

Scipedia content — Thu, 28 Jan 2021 17:50:28 +0100

Petrobras Transporte S.A. – TRANSPETRO’s Gas Pipeline System, composed by 7.3 thousand kilometers, 135 delivery stations and 21 compressor stations, has a very seasonally dependent operation. Highly linked with the Brazilian energy grid, during the dry season of the year a large part of the 77.3 million cubic meters of natural gas daily transportation are used to generate around 6.4 gigawatts to power the country. Additionally, the ever increasing number of power plants and distribution companies around the country demand more and more gas to be offered to supply the system. Among the different sources of natural gas available, the LNG is the most flexible for such seasonal operation."/jats:p" "jats:p"In order to support this current demand and to attend future demands, the regasification ability of Baía de Guanabara LNG Terminal was increased in December 2012, by changing the regasification vessel that supplies the southeast portion of the gas pipeline network, from 14 to 20 million cubic meters per day. To prepare to receive the new ship, some tests were performed to determine the operational limits on system survival time without LNG supply during vessel exchange. This assessment involved two different issues. The ship change operation occurred during a period of high consumption, when the LNG terminal was needed to sustain the network inventory. A long period without this supply, caused by the exchange of LNG vessel, would affect the deliveries. On the other hand, the new ship’s commissioning curve would introduce a large amount of natural gas into the system during a short period of time, demanding that the deliveries absorbed such volume. Four planning scenarios were assessed based on some expected pipeline supply and delivery conditions. The work was important as a reference for future changes on operating supply units of TRANSPETRO gas pipeline system, showing the importance of pipeline simulation both as a planning tool for pipeline logistic problems and as operational support.