Scipedia: Documents published in 2014

Energy Use and Emissions Impacts from Car Technologies Market Scenarios: A Multi-Country System Dynamics Model

Scipedia content — Wed, 03 Feb 2021 18:45:20 +0100

In the context of high energy use and greenhouse gas emissions from road passenger transport, the prospects of market diffusion of new car technologies is at present time uncertain. For instance, the impact of current oil prices on the market uptake of electric vehicles is yet to be seen. Systems thinking and scenario analysis are useful to explore possible future outcomes. This paper focuses on car technologies scenarios for the Chinese, German and US markets until 2030. The technologies investigated are: gasoline, diesel, flexi-fuel, liquefied petroleum gas, natural gas, hybrid, plug-in hybrid, battery electric and fuel cell vehicles. Based on the System Dynamics approach, a model integrating discrete choice and accounting frameworks is developed. The developed System Dynamics model is applied to examine alternative policies and to estimate energy use and emissions in each of the markets under various scenarios. The model results illustrate the importance of taking indirect emissions into account. In conclusion, simulated policies sensibly alter car technology uptake and have an impact on the environment. Finally, the ideas of feedback process and expansion of model boundaries are considered to be crucial in modeling such a complex and uncertain system.

Demand aggregator flexibility forecast: price incentives sensitivity assessment

Scipedia content — Wed, 03 Feb 2021 18:42:54 +0100

This work seeks to determine the potentials of a Demand Aggregator into the Demand Response scheme. The authors describe and validate the optimization technique used by the Aggregator to enable demand flexibility in domestic microgrid premises. The microgrid is comprised of Distributed Generation and shiftable load devices. By applying a monetary incentive signal in the microgrid's Energy Management System, the Aggregator empowers a change in the load profile, which signifies the potential of this concept in future electricity market and grid applications.

Realistic traffic scenarios using a census methodology: Vila real case study

Scipedia content — Wed, 03 Feb 2021 18:42:40 +0100

This paper presents the first phase of the redevelopment of the Electric Vehicle Scenario Simulator (EVeSSi) tool. A new methodology to generate traffic demand scenarios for the Simulation of Urban MObility (SUMO) tool for urban traffic simulation is described. This methodology is based on a Portugal census database to generate a synthetic population for a given area under study. A realistic case study of a Portuguese city, Vila Real, is assessed. For this area the road network was created along with a synthetic population and public transport. The traffic results were obtained and an electric buses fleet was evaluated assuming that the actual fleet would be replaced in a near future. The energy requirements to charge the electric fleet overnight were estimated in order to evaluate the impacts that it would cause in the local electricity network.

Leak detection and localization on hydrocarbon transportation lines by combining real-time transient model and multivariate statistical analysis

Scipedia content — Wed, 03 Feb 2021 18:39:46 +0100

Safety and reliability of hydrocarbon transportation lines (pipelines) around the world represents a critical aspect for industry, operators and population. Lines failures caused by external agents, corrosion, inadequate designs, among others, generate impacts on population, environment, infrastructure and economy, besides it may be catastrophically. Therefore, it is essential to constantly monitor operating conditions and hydraulic lines to faults and thus to take measures to mitigate the failure. Localization of leakage is more than comparison between simulated and measured flows, from the dynamic of these flows it can be inferred the localization of the leakage, and even its magnitude. One option is to develop an inverse Transient Model (TM) able to calculate parameters of the pipeline by using the measured flow. However, if the calculation of flows is computational expensive, the inverse calculation is even more. These phenomenological models reproduce as closely the response (flow and pressure) of the pipeline. The simulation contains information to optimize the pumping rate, the momentum and energy including a high number of inputs and constraints to consider that growing exponentially with the level of detail to get in the pipeline. Therefore, this method has a high computational cost. The other option is to simulate several scenarios by using TM and train some kind of classifier or predictor with the simulated measurements. The first phase of our complete proposed methodology under development is presented in this work. We have focused on carrying out simulations of pressure along a pipeline using TM and applying Principal Component Analysis (PCA) as a tool to recognize hided patterns which allow classify leakages in different locations and different magnitudes. doi: 10.12783/SHM2015/292

Document type: Conference object

Comparing supervised and unsupervised multiresolution segmentation approaches for extracting buildings from very high resolution imagery

Scipedia content — Wed, 03 Feb 2021 18:34:53 +0100

hough multiresolution segmentation (MRS) is a powerful technique for dealing with very high resolution imagery, some of the image objects that it generates do not match the geometries of the target objects, which reduces the classification accuracy. MRS can, however, be guided to produce results that approach the desired object geometry using either supervised or unsupervised approaches. Although some studies have suggested that a supervised approach is preferable, there has been no comparative evaluation of these two approaches. Therefore, in this study, we have compared supervised and unsupervised approaches to MRS. One supervised and two unsupervised segmentation methods were tested on three areas using QuickBird and WorldView-2 satellite imagery. The results were assessed using both segmentation evaluation methods and an accuracy assessment of the resulting building classifications. Thus, differences in the geometries of the image objects and in the potential to achieve satisfactory thematic accuracies were evaluated. The two approaches yielded remarkably similar classification results, with overall accuracies ranging from 82% to 86%. The performance of one of the unsupervised methods was unexpectedly similar to that of the supervised method; they identified almost identical scale parameters as being optimal for segmenting buildings, resulting in very similar geometries for the resulting image objects. The second unsupervised method produced very different image objects from the supervised method, but their classification accuracies were still very similar. The latter result was unexpected because, contrary to previously published findings, it suggests a high degree of independence between the segmentation results and classification accuracy. The results of this study have two important implications. The first is that object-based image analysis can be automated without sacrificing classification accuracy, and the second is that the previously accepted idea that classification is dependent on segmentation is challenged by our unexpected results, casting doubt on the value of pursuing ‘optimal segmentation’. Our results rather suggest that as long as under-segmentation remains at acceptable levels, imperfections in segmentation can be ruled out, so that a high level of classification accuracy can still be achieved.

Range extended engine management system for electric vehicles

Scipedia content — Wed, 03 Feb 2021 18:33:21 +0100

Quality of service guarantee in smart grid infrastructure communication using traffic classification

Scipedia content — Wed, 03 Feb 2021 18:19:16 +0100

fundamental requirement for smart grid is the design of a reliable and high performance communication infrastructure. The lack of timely access to information within domains of the smart grid serves as a real limit to detect and effectively react to system instability. Therefore, the delays are an important aspect and should be considered into any power system design or analysis. In this paper, we propose an IP/MPLS based communication infrastructure and optical fiber for the communication medium in the backbone network. In addition, in order to achieve the quality of service required for smart grid applications, traffic flows are classification into four classes using prioritize traffic and appropriate assignment of code point. Then, by using the Traffic Engineering with Diffserv (DS-TE) and active queue management algorithms as well as RIO, the quality of service is guaranteed in an acceptable level. (4 pages)

Robust Networks to Cascading Failures

Scipedia content — Wed, 03 Feb 2021 18:17:46 +0100

Nowadays, the ongoing progress of networking in essential utilities such as the Internet, the WWW, transportation networks, electrical power grid networks, etc., brings significant benefits to the quality of our life. However, networked systems hold a certain danger that a failure of a single node in the system may diffuse to all other nodes. This chain of failure is widely known as cascading failure. Examples of cascading failure include disease epidemics, traffic congestion, electrical power system blackouts, and so on. In these systems, if external shocks or excess loads at some nodes are propagated to other connected nodes due to failure, the domino effects often come with disastrous consequences. Thus, how to prevent cascading failures in complex networks becomes an important emergent issue. In this paper, we consider an overload-based cascading failure model and design a robust network structure against this type of cascading failure. Numerical simulations show that the proposed network, which consists of a complete cluster of connected hub nodes, and periphery nodes connecting one of hub nodes in the cluster, is least susceptible to cascading failures compared with other types of networks.

Innovation performance of the transport sector at regional level

Scipedia content — Wed, 03 Feb 2021 18:03:24 +0100

Transport is a key enabler of economic and social activity and a major industry in the European economy. However, transport is also a source of environmental concerns and other negative externalities. Improving the efficiency of the transport system, mitigating its negative impacts and increasing the competitiveness of the transport industry are the key challenges of EU policy. Innovation is essential for the European transport strategy to achieve these challenges. Acknowledging the fact that regions are important engines of economic development, regional innovations can be important drivers for growth and improvement of the transport sector in Europe. The innovation process and relative performance of the transport sector at regional level is, however, not extensively studied. In the framework of the European FP7-funded project METRIC a method has been developed to measure and explain the innovation performance of the transport sector at regional level. This paper outlines this method and presents the results of applying this method to 251 European regions. The method is based on structural equation modelling. This modelling technique enables to get scores for the innovation performance of each region and to derive estimations that express the relative importance of the explanatory factors for innovation performance. The analysis showed that the high performing regions were predominantly found in Germany and Sweden, while the low performing regions were located in Finland, Poland, Romania, Bulgaria, Hungary, Spain and United Kingdom. However, the scores of regions on innovation performance are rather different when the performance is measured for the transport manufacturing and transport service sector individually. Among the factors that may explain transport innovat ion performance of regions funding possibilities appear to be highly important, while the relevance of innovation milieu is outmost limited.

Monitoring head dynamics for driver assistance systems: A multi-perspective approach

Scipedia content — Wed, 03 Feb 2021 17:59:18 +0100

visually demanding driving environment, where elements surrounding a driver are constantly and rapidly changing, requires a driver to make spatially large head turns. Many existing state of the art vision based head pose algorithms, however, still have difficulties in continuously monitoring the head dynamics of a driver. This occurs because, from the perspective of a single camera, spatially large head turns induce self-occlusions of facial features, which are key elements in determining head pose. In this paper, we introduce a shape feature based multi-perspective framework for continuously monitoring the driver's head dynamics. The proposed approach utilizes a distributed camera setup to observe the driver over a wide range of head movements. Using head dynamics and a confidence measure based on symmetry of facial features, a particular perspective is chosen to provide the final head pose estimate. Our analysis on real world driving data shows promising results.

Real-time bus route state forecasting using particle filter: An empirical data application

Scipedia content — Wed, 03 Feb 2021 17:55:47 +0100

ISTS 2014 - 4th International Symposium of Transport Simulation, Ajaccio, FRANCE, 01-/06/2014 - 04/06/2014; Buses on the same route tend to bunch when the system is uncontrolled. This lack of regularity leads to an increase in the average passenger waiting time, increases delays and makes travel times uncertain. A wide variety of solutions have been proposed to maintain accurate bus system performance. Unfortunately, if a strategy is applied permanently, it could detract from the entire transport system efficiency. That is why a transit operator needs an accurate forecast of the route in order to intervene before the bus route is too disrupted to be restored to regularity. This paper aims to predict critical situations in real-time forecasting of a bus route state. To accomplish this, we propose to take advantage of both theoretical and empirical information (model and data) using data assimilation (a particle filter). On one hand, a stochastic dynamic bus model forecasts future bus route states. On the other hand, archived data calibrates the model parameters while real-time data provides information about the actual route state. The methodology is applied to a real case study thanks to the quality data provided by TriMet (the Portland, Oregon transit district). Predictions are finally evaluated by an a posteriori comparison with real data. The results highlight that the method leads to a valid forecast of a bus route state with a 8 minutes time window. This duration is sufficient to predict critical situations, especially bus bunching. Further research would have to consider deterministic travel times from a traffic model instead of the distributions in order to maintain correlation between travel times on links. In that case, the assimilation process would focus on the surrounding traffic flow, also potentially available in the Portland data.

Detection of Internal Defects in As-Built Pipelines for Structural Health Monitoring: A Sensor Fusion Approach Using Infrared Thermography and 3D Laser-Scanned Data

Scipedia content — Wed, 03 Feb 2021 17:45:46 +0100

Internal defects of pipelines are among the main factors causing accidents in the production phase of industrial plants. Periodic monitoring of a pipeline’s inner surface condition is of great importance for minimizing the risk of failure of industrial plants. This study proposes a sensor fusion approach to detect internal defects automatically in as-built pipelines during their service lives to ensure structural safety. The proposed approach uses infrared thermography combined with threedimensional (3D) laser-scanned data. For this purpose, a multi-sensor system equipped with a thermal infrared camera and a 3D laser scanner was internally and externally calibrated. From the combined data set, 3D points corresponding to the as-built pipelines are extracted from laser-scanned data. Then, thermographic analysis of the corresponding thermal data of those pipelines is performed. In this step, the local thermal gradients on the pipeline’s surface are calculated to detect areas having different thermal values. In addition, the global thermal gradients along the longitudinal or radial axes of the pipeline are calculated to determine the consistency of its internal thickness. The field experiment was performed at an operating petrochemical plant to validate the proposed approach. The experimental results revealed that the proposed approach has potential for detecting internal defects in as-built pipelines from infrared thermography combined with 3D laser-scanned data.

Requirements for Communication Systems in Future Passenger Air Transportation

Scipedia content — Wed, 03 Feb 2021 17:43:36 +0100

The Airports Council International (ACI) estimates that the number of global passengers will increase from over 5 billion passengers today to 12 billion by 2031. At the same time, major aircraft (A/C) manufacturers like Boeing and Airbus estimate that the worldwide commercial A/C fleet will increase 5% per year over the next 20 years, i.e. the commercial aviation market will be doubled. This growth will require not only new airports infrastructure but also investments in en-route and Air Traffic Management (ATM) systems. Part of such investments must be aimed to a growth in the capacity of the onboard communication systems. With increasing speed of Internet connections on land, passengers expect not only to be connected to the Internet but also to have good connectivity with high bandwidth to enable them the access and use of multitude applications during the flight. The need to be connected adds to the increased passenger traffic and even the implementation of new aviation standards such as: Controller-Pilot Data Link Communications (CPDLC), Future Air Navigation System (FANS), Automatic Dependent Surveillance-Broadcast (ADS-B), VHF Data Link mode 2/3/4 (VDL2/3/4), etc. Governmental initiatives such as NextGen in U.S.A. and Single European Sky ATM Research (SESAR) in Europe are forcing aviation companies to fulfill these needs to satisfy their customers while complying with regulations in different airspaces. As a result, the aviation industry faces a new paradigm in the communication system requirements, which is the subject of this paper. As a first requirement, the industry must be prepared for seamlessly adoption of future communication systems, standards, or regulation without this implying the continuous installation of new equipment, but rather the modification of the existing one. Today, any modernization of these systems represents a major change in airborne and on-land equipment, which means buying new equipment, installation of new antennas on the A/C, etc. The main repercussions of this lack of flexibility and scalability are that many of the systems currently used have become obsolete, their modernization, when possible, is highly constrained by previous limitations, and new deployments are painfully long. Therefore, the modernization of the onboard communication systems has to be flexible enough to address all these drawbacks. This paper also discusses several Requirements for Communication Systems in Future Passenger Air Transportation (RCSFPAT). Requirements like the bandwidth, which will depend on factors that cannot yet be predicted accurately (amount of increase in air traffic, capabilities of service providers, etc.). The two primary drivers for the RCSFPAT are: 1) to provide an appropriate communication infrastructure to support future air communication systems growth, and 2) to provide a consistent global solution to support the goal of fulfilling the communications requirements from passengers and communications between A/C Earth Stations (AESs) and Ground Earth Stations (GESs) thus to ensure flight safety. In order to provide worldwide coverage of the communication systems, the only current technology able to cover the oceanic regions is Satellite Communications (SatCom). Indeed, most of the airlines and A/C manufactures have signed

Simulation-based evaluation of I2V systems’ impact on traffic performance: case study – COOPERS

Scipedia content — Wed, 03 Feb 2021 17:41:22 +0100

In-vehicle technologies and cooperative services are attracting a lot of attention for their potential to deal with congestion problems and improve traffic safety. This paper aims to investigate the impact of infrastructure-to-vehicle cooperative systems, case of COOPERS, at the aggregate level, on traffic performance. A factorial experiment is designed with two factors: traffic demand and penetration of the system with three levels each. In total, nine scenarios are investigated. To replicate driving behavior with and without the system, speed distributions from a simulator experiment are used. A motorway section of 4 km is built in VISSIM simulation software. Indicators such as speed, density, delays and travel times are chosen to evaluate and compare the motorway performance with and without the system. The results show that drivers driving with the system activated are more aware and alert to near future traffic conditions compared to driving without the system. Driving with the system activated is characterized by smoother and longer speed decelerations when approaching critical incident/accident events. The results show as well that the factors investigated significantly impact the motorway performance. Congestion reduces the impact of the system whereas higher penetration levels improve traffic operation on the motorway. Future research directions can include (1) investigating the impact of the system at the micro level such as lane changing or car-following behaviors; (2) levels of compliance with the system, which is an important aspect as well.

Evaluating Tradeoff between Environmental Impact and Operational Costs for Enroute Air Traffic

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

The rapid growth of air traffic has drawn attention to aircraft-induced environmental impact. Aviation operations affect the environment mainly through the release of emissions and by the formation of contrails. Recent research has shown that altering aircraft cruise altitudes can reduce aviation environmental impact by reducing Absolute Global Temperature Change Potential, a climate assessment metric that adapts a linear system for modeling the global temperature response to aviation emissions and contrails. However, these methods will increase fuel consumption that leads to higher operational costs imposed on airlines resulting in reluctance to adopt a new routing strategy. This paper evaluates the tradeoff between environmental impact reduction and the corresponding added operational costs for enroute air traffic. The concept of social cost of carbon and the carbon auction price from California’s recent cap-and-trade system were used to provide estimates and a methodology to evaluate environmental costs for carbon dioxide emissions and contrail formations. Depending on the specific environmental policy, the strategy is considered favorable when the reduction in environmental costs exceeds the increase in operational costs. The results show how the net environmental benefit varies with different decision-making time horizons, different carbon and fuel costs, and different days. The study provides guidance towards the development of the environmental reduction strategies.

An approach towards sustainable passenger mobility in urban areas: a life cycle perspective

Scipedia content — Wed, 03 Feb 2021 17:34:17 +0100

Today the high transport demand in urban areas causes high energy consumption and great environmental repercussions such as air and noise pollution, increasing shortage of space, high congestion and traffic jams [1–6]. Numerous studies have already proven that technological improvements alone will not be able to solve all of these problems [7–9]. In order to achieve a more sustainable passenger transportation system the mobility patterns themselves have to undergo certain changes. That goal may be achieved by combining three key elements: (1) technological improvements, (2) user behavior in terms of a modal shift to collective/public or non-motorized transport and (3) user behavior in terms of avoidance of traffic by utilizing information and communication technologies (ICT), intelligent transport systems (ITS) and decrease of travel distances [7–9]. A research project is undertaken to quantitatively assess the environmental and economic implications of the three key elements from a life cycle perspective in an urban area. Various means of transportation such as individual vehicular transport as well as public transport using passenger vehicles, trams, subways etc. with electric propulsion system will be considered. The assessment of next generation chemical storage units (batteries, supercapacitors) utilized by the various vehicles will be a large focus. The presented methodology aims at quantitatively assessing a defined excerpt of future urban mobility in order to analyze the economic and ecological performance of the three key elements one by one and in combination. Thus, pathways towards a more sustainable urban passenger transport will be identified to support decision makers in traffic and mobility management.

Advanced bus transit systems – “best practice” mobility solutions for emerging agglomerations

Scipedia content — Wed, 03 Feb 2021 17:31:49 +0100

This paper on advanced bus transit systems is from the proceedings of 14th International Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors contend that most of developing countries lack the necessary financial and planning resources to establish rail-based systems (metro, light rail), so the need for bus-based public transport technology is inevitable, independent of any political desires and programs. They describe how unorganized private minibuses (“paratransit”) are currently taking a growing share of mobility in large cities in developing nations, causing major environmental and traffic problems due to inefficient use of roadspace and outdated vehicle technology. They propose the use of advanced bus systems, such as “Bus Rapid Transit” (BRT) systems, which have proven successful and economically efficient in a number of Latin American and European conurbations, as a potential solution that is based on readily-available vehicle technology and local capacities in conventional road building. The authors conclude that the sustainability balance, the transportation performance, and the financial requirements of these systems are very positive, especially when coordinated with an integrated town-planning approach.

Modelling Mixed 4phase Pipelines: Structures and Patterns

Scipedia content — Wed, 03 Feb 2021 17:28:20 +0100

This paper presents an exploration of the design space for homogeneous and mixed 4phase asynchronous linear pipelines. We extend previously published results by uncovering their complete ordered design space, demonstrate relationships between the latter's governing lattice structures, tabulating the ways in which mixed linear pipelines compose, and establish the basic rules underpinning mixed pipeline behaviours. The inherent structures and patterns we describe give rise to a succinct and transparent method for calculating the specifications of mixed and homogeneous pipelines of arbitrary depths. Practical applications of this theory are demonstrated.

On the effects of energy-aware traffic engineering on routing reliability

Scipedia content — Wed, 03 Feb 2021 17:27:42 +0100

Current network infrastructures are over-provisioned to increase their resilience against resource failures, e.g., bundled links and nodes, as well as congestion during peak hours. However such strategies waste resources as well as exhibit poor energy efficiency at off-peak periods. To this end, several energy-aware routing algorithms have been proposed to maximally switch off redundant network resource at low traffic load to minimize energy usage. These routing solutions, however, do not consider network reliability as critical back-off links/nodes maybe switched off. Henceforth, we aim to quantify the effects of five recently proposed green routing approaches, namely FGH, GreenTE, MSPF, SSPF, and TLDP, on the following two reliability measures: (i) 2-terminal reliability (ii) path reliability. Experiments using three topologies with real and synthetic traffic demands show that switching off redundant links significantly affects the 2-terminal reliability. Routing traffic through multiple paths has lesser reliability impact while reducing energy, especially when the paths are link disjoint. Interestingly, TDLP and MSPF have better path reliabilities than using shortest path routing.

The compulsive habit of cars

Scipedia content — Wed, 03 Feb 2021 17:24:11 +0100

The car dependence of people living in contemporary cities is a major concern for policy makers, who often find it difficult to persuade people into more sustainable transport modes. By contrast, recent insights from neuroscience have shown that a broad spectrum of behaviors can become habitual and, thus, resistant to change. Here, we outline the potential of collaboration between neuroscience and human geography aiming at a better understanding of habits that determine everyday commuting routines.

Targeting the introduction of E-bikes based on behaviour change potential and user perception

Scipedia content — Wed, 03 Feb 2021 17:22:21 +0100

Conventional bike-sharing schemes have been introduced in cities as an urban mobility option, reducing car usage and alleviating public transport; however, cycling shares in Goteborg is one of the lowest in Europe. Goteborg has been dedicated to increase the share of sustainable transport in the city. The Electric bicycle (E-bike), which offers a greater form of service than the conventional bicycle, then appears to be rather interesting to policy makers. This study is carried out with the goal to open the door for E-bikes in Goteborg by identifying potential for change from car users to E-bike users. First, the current situation of Swedish perception on cycling and policy were analyzed with a literature review. Second, the authors explore whether E-bikes can remove barriers or provide the same benefit of the alternative modes for people in Goteborg. At the third phase, the geographical potential of E-bikes in Goteborg was identified on three bases: the ratio of cyclist using cars for commuting purposes, travel distance, and the barriers removed. The result suggested that E-bikes theoretically remove the barriers expressed by 53% of people in Goteborg when comparing to regular bicycles. A public E-bike pool is a good solution for overcoming the first two phases of behavioral change, by demonstrating the technology and creating a public supply of E-bikes. Hisingen is the area with the greatest potential to adopt E-biking habits, setting up an E-bike pool in Hisingen can hypothetically substitute around 5% of commuting trips done by the car users who have the capacity to cycle. For the entire Goteborg area, up to 4% of the trips less than 10 km could be replaced by E-bikes. Together with the proper policy strategy, a change towards sustainable transport mode could be realized supported by wide acceptance among the general public.

Model Complexities and Requirements for Multimodal Transport Network Design

Scipedia content — Wed, 03 Feb 2021 17:20:26 +0100

In the aim for a more sustainable transport system, governments try to stimulate multimodal trip making by facilitating smooth transfers between modes. The assessment of related multimodal policy measures requires transport models that are capable of handling the complex nature of multimodality. This complexity sets requirements for adequate modeling of multimodal travel behavior and can be categorized into three classes that are related to the range and combinatorial complexity of the available alternatives, the mathematical complexity of modeling the choice between them, and the complex effect of demand–supply interactions. Classical modeling approaches typically fail to meet these requirements and state-of-the-practice approaches only partly fulfill them. Therefore, the underlying hypothesis of this study was that the application of such models in network design implied an ill-advised decision-making process. Thus, these modeling approaches, as well as the promising state-of-the-research supernetwork approach, were conceptually compared with each other. Requirements for multimodality were constructed, and all three models were tested on the way in which these requirements can be met. The findings of this conceptual comparison were supported by realistic examples in the real-world transport network of the Amsterdam Metropolitan Area in the Netherlands. The theoretical shortcomings of the classical and state-of-the-practice approach were shown to indeed result in implausible predictions of multimodal travel behavior. The flexibility of the supernetwork approach, however, was very capable of describing the expected effect of supply changes on travel behavior in most situations. This study illustrates the urgency for applying sound multimodal modeling approaches in network design studies.

Composite Repair Performance at Elevated Temperatures

Scipedia content — Wed, 03 Feb 2021 17:15:38 +0100

For the better part of the past 20 years composite materials have been used to repair damaged piping and pressurized components in plants, refineries, and pipelines. The use of composite materials has been accompanied by comprehensive research programs focused on the development and assessment of using composite technology for restoring integrity to damaged piping and pressurized components. Of particular interest are composite repair standards such as ISO 24817 and ASME PCC-2 that provide technical guidance in how to properly design composite repair systems."/jats:p" "jats:p"The vast body of research completed to date has involved assessments at ambient conditions; however, at the present time there is significant interest in evaluating the performance of composite repair materials at elevated temperatures. This paper is focused on the topic of high temperature composite repairs and addresses the critical role of utilizing temperature-based mechanical properties to establish a composite repair design. The backbone of this effort is the development of composite performance curves that correlate change in strength as a function of temperature. A discussion on supporting full-scale pressure test results are included, along with guidance for users in how to properly design composite repair systems for applications at elevated temperatures.

Real-time Energy Resource Scheduling considering a Real Portuguese Scenario

Scipedia content — Wed, 03 Feb 2021 17:12:06 +0100

The development in power systems and the introduction of decentralized generation and Electric Vehicles (EVs), both connected to distribution networks, represents a major challenge in the planning and operation issues. This new paradigm requires a new energy resources management approach which considers not only the generation, but also the management of loads through demand response programs, energy storage units, EVs and other players in a liberalized electricity markets environment. This paper proposes a methodology to be used by Virtual Power Players (VPPs), concerning the energy resource scheduling in smart grids, considering day-ahead, hour-ahead and real-time scheduling. The case study considers a 33-bus distribution network with high penetration of distributed energy resources. The wind generation profile is based on a real Portuguese wind farm. Four scenarios are presented taking into account 0, 1, 2 and 5 periods (hours or minutes) ahead of the scheduling period in the hour-ahead and realtime scheduling.

A flexible, efficient and accurate framework for community question answering pipelines

Scipedia content — Wed, 03 Feb 2021 17:04:39 +0100

hough deep neural networks have been proving to be excellent tools to deliver state-of-the-art results, when data is scarce and the tackled tasks involve complex semantic inference, deep linguistic processing and traditional structure-based approaches, such as tree kernel methods, are an alternative solution. Community Question Answering is a research area that benefits from deep linguistic analysis to improve the experience of the community of forum users. In this paper, we present a UIMA framework to distribute the computation of cQA tasks over computer clusters such that traditional systems can scale to large datasets and deliver fast processing.

Heterogeneous processor pipeline for a product cipher application

Scipedia content — Wed, 03 Feb 2021 17:04:10 +0100

Processing data received as a stream is a task commonly performed by modern embedded devices, in a wide range of applications such as multimedia (encoding/decoding/ playing media), networking (switching and routing), digital security, scientific data processing, etc. Such processing normally tends to be calculation intensive and therefore requiring significant processing power. Therefore, hardware acceleration methods to increase the performance of such applications constitute an important area of study. In this paper, we present an evaluation of one such method to process streaming data, namely multi-processor pipeline architecture. The hardware is based on a Multiple-Processor System on Chip (MPSoC), using a data encryption algorithm as a case study. The algorithm is partitioned on a coarse grained level and mapped on to an MPSoC with five processor cores in a pipeline, using specifically configured Xtensa LX3 cores. The system is then selectively optimized by strengthening and pruning the resources of each processor core. The optimized system is evaluated and compared against an optimal single-processor System on Chip (SoC) for the same application. The multiple-processor pipeline system for data encryption algorithms used was observed to provide significant speed ups, up to 4.45 times that of the single-processor system, which is close to the ideal speed up from a five-stage pipeline.

Sustainable Distribution in the Consumer Goods Supply Chain

Scipedia content — Wed, 03 Feb 2021 17:02:19 +0100

Sustainability in logistics and efforts to increase economic gains while managing the impact on the environment and on society have been discussed in all spheres of companies' decision-making processes. Especially in the consumer goods industry, customers' pressures are becoming more intense, not only related to product stewardship but also to supply chain responsibility. This paper intends to discuss how companies have been preparing themselves or reacting to these new demands. Using the content analysis method, practices published in public reports and implemented by top ranked sustainable companies were collected and analyzed. The practices were structured according to a newly developed framework for sustainable supply chains and are focused on distribution activities. These activities account for a large percentage of companies' carbon footprint and therefore offer ample opportunity for improvements in sustainability. The results show that the bulk of companies' investments related to sustainability is in Equipment and Vehicles technologies, especially battery electric vehicles. To understand more about this new trend, a survey was conducted with 33 companies from different industries in order to detect business users' profiles as well as their technical characteristics. The paper's results include insights about the challenges and opportunities in the consumer goods industry towards a sustainable supply chain network.

MIMO Hinf control for power source coordination - application to energy management systems of electric vehicles

Scipedia content — Wed, 03 Feb 2021 16:59:03 +0100

International audience; This paper deals with a control strategy used for designing energy management systems within average-power electric vehicles. The power supply system is composed of three sources, namely a fuel cell, a battery and an ultracapacitor - specialized within distinct frequency ranges - which must be coordinated in order to satisfy power demand of the vehicle's electrical motor. The three sources with their associated DC-DC converters are paralleled on a common DC-bus supplying the electrical motor. The DC-bus is required to be constant regardless of the load state thanks to the fuel cell which provides the mean power and to the other two sources - auxiliary sources - which are controlled to supply the high-frequency variations of power demand according to an H1 optimization strategy. MATLAB/ Simulink numerical simulation is used to validate the proposed strategy under real driving cycle condition proposed by IFSTTAR (Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux), and this approach is assessed against another optimal strategy that uses LQR as control design.

Maritime Transport VI

Scipedia content — Wed, 03 Feb 2021 16:57:26 +0100

Safely conducting airport surface trajectory-based operations

Scipedia content — Wed, 03 Feb 2021 16:42:56 +0100

piloted simulation study was conducted at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) to evaluate the ability to safely conduct surface trajectory-based operations (STBO) by assessing the impact of providing traffic intent information, conflict detection and resolution (CD&R) system capability, and the display of STBO guidance to the flight crew on both head-down and head-up displays (HUD). Nominal and off-nominal conflict scenarios were conducted using 12 airline crews operating in a simulated Memphis International Airport terminal environment. The flight crews met their required time-of-arrival at route end within 10 seconds on 98 percent of the trials, well within the acceptable performance bounds of 15 seconds. Traffic intent information was found to be useful in determining the intent of conflict traffic, with graphical presentation preferred. The CD&R system was only minimally effective during STBO because the prevailing visibility was sufficient for visual detection of incurring traffic. Overall, the pilots indicated STBO increased general situation awareness but also negatively impacted workload, reduced the ability to watch for other traffic, and increased head-down time.

Standard Deviation of Travel Time in a Freeway Network--A Mathematical Quantifying Tool for Reliability Analysis

Scipedia content — Wed, 03 Feb 2021 16:39:15 +0100

Travel time reliability is a new way of looking at congestion and unpredictable variation of travel time. The standard deviation of travel time is a good indicator for investigating reliability of a network. This paper presents a mathematical model dealing with the standard deviation of the total travel time within a freeway network. In general, the distribution of the travel time of links and the distribution of delays at bottlenecks can be described by different probability distributions. The parameters of those distributions can be calibrated by measurements or simulation studies. However, it is hard to calculate the standard deviation or variance of travel time of a route consisting of several consecutive links or bottlenecks. The presented paper shows that, under some assumptions, the variance of the total route travel time can be calculated as the sum of the variances of the single links or bottlenecks in case that the travel times and the delays are independent of each other. In reality the independency between the consecutive links or bottlenecks may not be satisfied. In this case the variance of the total travel time can also be estimated given the correlation coefficient between the two consecutive links or bottlenecks. Again, this correlation coefficient can be calibrated by measurements or by simulation studies. Once the variance in the travel time is known, the standard deviation is also known. Using the proposed model, the standard deviation of travel time - and, thus, the reliability of a freeway network - can be quantitatively estimated given the geometric design of the freeway network and the traffic demand.

Investigating the contribution of Demand Responsive Transport to a sustainable local public transport system

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

Various studies have advocated the potential for Demand Responsive Transport (DRT) services to deliver sustainable local public transport. This paper investigates the sustainability credentials of DRT services using evidence from UK-based research. More specifically, six potential DRT market niches were identified, including those which offer potential commercial opportunities (e.g. airport surface access) and those that meet social needs (e.g. non-emergency hospital trips). Mode share of these DRT services, against car or bus travel, was simulated from mixed logit models within a panel data modelling framework estimated from survey data. The survey was conducted of over 400 respondents in urban (Rochdale, Manchester) and rural (Melton Mowbray, Leicestershire) areas.Experience shows that it is particularly difficult to make DRT services financially viable. Of the DRT services investigated, those targeting airline or train passengers offer potential. However, they are in direct competition with the car, and so their success depends on the cost and availability of parking spaces. Some of the DRT schemes explored meet social needs, such as to access shopping facilities or hospitals, but they face cost challenges. In addition, institutional barriers for new DRT schemes need to be overcome in order to develop a sustainable local public transport system.

Modelling the non-equilibrium two-phase flow during depressurisation of CO2 pipelines

Scipedia content — Wed, 03 Feb 2021 16:36:23 +0100

The development, testing and validation of a two-fluid transient flow model for simulating outflow following the failure of high pressure CO 2 pipelines is presented. Thermal and mechanical non-equilibrium effects during depressurisation are accounted for by utilising simple constitutive relations describing inter-phase mass, heat and momentum transfer in terms of relaxation to equilibrium. Pipe wall/fluid heat exchange on the other hand is modelled by coupling the fluid model with a finite difference transient heat conduction model. The two-fluid transient flow model's performance is tested by comparison of the predicted transient pressure and temperature profiles along the pipeline against those based on the simplified homogeneous equilibrium model (HEM) as well as real data captured during the full bore rupture of a 260 m long, 233 mm internal diameter pipeline containing CO 2 at 36 bara and 273 °C. The two-fluid model is found to produce a reasonably good degree of agreement with the experimental data throughout the depressurisation process. The HEM based flow model on the other hand performs well only near the rupture plane and during the early stages of the depressurisation process.

Document type: Article

Automatic fitting procedure for the fundamental diagram

Scipedia content — Wed, 03 Feb 2021 16:33:06 +0100

The fundamental diagram of a road, including free flow capacity and queue discharge rate, is very important for traffic engineering purposes. In the real word, most traffic measurements come from stationary loop detectors. This paper proposes a method to fit Wu’s fundamental diagram to loop detector data. Wu’s fundamental diagram is characterised by five parameters, being the free flow speed, wave speed, free flow capacity, queue discharge rate and jam density. The fits appear to be not very sensitive to the right value for the wave speed or the free flow speed. The proposed method therefore entails fixing these two parameters. The method consists of two steps. We first use a triangular fundamental diagram to separate the congested branch from the free flow branch. Then, the remaining three parameters of Wu’s fundamental diagram are fitted on each of the branches using a least square fit. This method is shown to be robust for cases tested in real life, and hence very noisy, data.

Combined solution of capacity expansion and signal setting problems for signalized road networks

Scipedia content — Wed, 03 Feb 2021 16:30:55 +0100

Traffic congestion has been growing at an unsustainable rate and decreasing the quality of life of people living in many countries especially in last few decades. At the same time, congestion causes decreasing accessibility and mobility whereas it leads to increase travel time and air pollution. Although various optimization techniques in determining signal timings or optimal capacity expansion have been discussed separately in the literature, few studies have been considered for solving the both problems simultaneously. Thus, it can be emphasized that the majority of literature fails to highlight an indispensable relationship between these two problems. To fill this gap, a bi-level solution methodology based on Differential Evolution ( DE) algorithm is proposed in this study. The upper level deals with minimizing total system travel cost under given budget and signal timing plan while the User Equilibrium link flows are determined by VISUM at the lower level. In this study, the DE based solution algorithm is coded in VBA which is combined with VISUM for solving the problem. In order to illustrate the efficiency of the proposed algorithm, it is applied to real data of Sioux-Falls city network which has 76 links, 24 nodes and 552 OD trips. In this network, 7 nodes are considered as signalized junction, and 16 links which connect these nodes are chosen as candidate for capacity expansion. Results indicated that the proposed algorithm shows significant performance in solving the combined problem for signalized road networks. (C) 2015 The Authors. Published by Elsevier B.V.

High Speed Rail System and the Tourism Market: Between Accessibility, Image and Coordination Tool

Scipedia content — Wed, 03 Feb 2021 16:26:04 +0100

he aim of this P is to propose a state-of-the-art concerning the interaction between High-Speed Rail systems and the tourism market, in order to identify the possible best practices aiming to enhance the value of the tourist activities. This question arises because there are many projects of High-Speed Rail and others are ongoing, whose economic justification is based on the benefits deriving from them. In November 2013 there were 21.472 km of High Speed Railways (i.e., whose speed is greater than 250 km / h) in the world, 13964 km were under construction and 16347 km were scheduled by 2025. In 2025, 51784 km should be operational (UIC 2013), as in Germany, Belgium, Brazil, China, the United States, France, Iran, Morocco, and Portugal. Because of increase in accessibility, which the territories served benefit, the actors involved expect a dynamic economy, in general, and of the tourism in particular. Although expectations are important in France as abroad, a literature review of studies carried out ex-post shows that the effects are not systematic. Indeed, there is not a systematic dynamism because of the implementation of the High-Speed service. More specifically, we show that different types of tourism are variously impacted by High-Speed Rail service. Urban and business tourism are the most impacted ones. Specifically, we show the importance of the prior existence of famous cities. These last ones must offer a basket of tourist products and services that benefit a good accessibility from being served by a High Speed Rail station. But it can be noted also that, if the high speed allows, in some circumstances, the increase in the number of tourists, a decrease of stay is also possible. Moreover, as the number of cities served by High Speed Rail increases, High Speed Rail can be itself a differentiation asset to develop tourism market. The role of high speed should also be related to accessibility, understood both as attractiveness of the destination such as coordination of the actors in order to propose a coordinated and renewed supply.

Field oriented control of an axial flux permanent magnet synchronous motor for traction solutions

Scipedia content — Wed, 03 Feb 2021 16:22:24 +0100

Electric Vehicles (EVs) are increasingly used nowadays, and different powertrain solutions can be adopted. This paper describes the control system of an axial flux Permanent Magnet Synchronous Motor (PMSM) for EVs powertrain. It is described the implemented Field Oriented Control (FOC) algorithm and the Space Vector Modulation (SVM) technique. Also, the mathematical model of the PMSM is presented. Both, simulation and experimental, results with different types of mechanical load are presented. The experimental results were obtained using a laboratory test bench. The obtained results are discussed. F CT – Fundação para a Ciência e Tecnologia in the scope of the project: PEst - OE/EEI/UI0319/2014

Distribution of pseudonym certificates via bursts for VANETs with low and medium mobility

Scipedia content — Wed, 03 Feb 2021 16:15:24 +0100

Wireless intelligent transport systems based on Car-to-X communication technology are about to enter the mass market in upcoming years. Thereby, efficient and reliable security systems are a core point of concern in system design. Currently regarded digital signature schemes using pseudonym certificates can introduce significant overhead into the highly bandwidth restricted system. Thus, mechanisms to optimize the efficiency of the security mechanisms in regard to authentication delay and channel load are required. Prior work has focused on scenarios with high node mobility, e.g., Freeways. However, bandwidth conserving mechanisms are also required for urban low and medium mobility scenarios to enable foreseen extension of the wireless network for the many other volatile road users like pedestrians. Hence, an approach for efficient pseudonym certificate distribution in urban scenarios is provided in this work. The given simulation based environment shows that it can enhance cooperative awareness while limiting used bandwidth. Thus, it can be regarded as well suitable for future urban intelligent transport systems.

Benefits of a unified LaSRS++ simulation for NAS-wide and high-fidelity modeling

Scipedia content — Wed, 03 Feb 2021 16:14:27 +0100

The LaSRS++ high-fidelity vehicle simulation was extended in 2012 to support a NAS-wide simulation mode. Since the initial proof-of-concept, the LaSRS++ NAS-wide simulation is maturing into a research-ready tool. A primary benefit of this new capability is the consolidation of the two modeling paradigms under a single framework to save cost, facilitate iterative concept testing between the two tools, and to promote communication and model sharing between user communities at Langley. Specific benefits of each type of modeling are discussed along with the expected benefits of the unified framework. Current capability details of the LaSRS++ NAS-wide simulations are provided, including the visualization tool, live data interface, trajectory generators, terminal routing for arrivals and departures, maneuvering, re-routing, navigation, winds, and turbulence. The plan for future development is also described.

Network of automated vehicles: the AutoNet 2030 vision

Scipedia content — Wed, 03 Feb 2021 16:13:58 +0100

onic proceedings; International audience; AutoNet2030 - Co-operative Systems in Support of Networked Automated Driving by 2030 - is a European project connecting two domains of intensive research: cooperative systems for Intelligent Transportation Systems and Automated Driving. Given the latest developments in the standardization of vehicular communications, vehicles will soon be wirelessly connected, enabling cooperation among them and with the infrastructure. At the same time, some vehicles will offer very advanced driving assistance systems, ranging from Cooperative Adaptive Cruise Control (C-ACC) to full automation. The research issues addressed in AutoNet2030 are as follows: how can all these vehicles with different capabilities most efficiently cooperate to increase safety and fluidity of the traffic system? What kind of information should be exchanged? Which organization (e.g. centralized or distributed) is the best? The purpose of this paper is to introduce the vision and concepts underlying the AutoNet2030 project and the direction of this ongoing research work.

ADS-B vulnerability to low cost jammers: Risk assessment and possible solutions

Scipedia content — Wed, 03 Feb 2021 16:10:31 +0100

utomatic Dependent Surveillance-Broadcast (ADS-B) systems provide to the air traffic control centers flight and status information of the cooperating targets. Problems due to jamming and/or spoofing of the ADS-B channel are under study, as well as verification and validation techniques. In this paper, we show how a low cost jammer can affect an ADS-B receiver. Three types of threats were evaluated. A multichannel receiver permitted to evaluate the received signal stream with and without jammer. The measurements were carried out coupling the receiver antenna with the in-cable jammer radio frequency (1090 MHz) signal. The results show the detection loss as a function of jammer range and jammer type. Finally, possible solutions are proposed to mitigate the effects. Some trials to evaluate their effectiveness are described.

Optimizing Wellfield Operation in a Variable Power Price Regime

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

Wellfield management is a multi-objective optimization problem. One important management objective has been energy efficiency in terms of minimizing the energy footprint (EFP) of delivered water (MWh/m3). However, power systems in most countries are moving in the direction of deregulated power markets and power price variability is increasing in many markets because of increased penetration of intermittent renewable power sources. In this context the relevant management objective becomes minimizing the cost of energy used for pumping and distribution of groundwater rather than minimizing energy use itself."br/""br/"We estimated energy footprint as a function of wellfield pumping rate (EFP-Q relationship) for a wellfield in Denmark using a coupled well and pipe network model. This EFP-Q relationship was subsequently used in a stochastic dynamic programming framework to minimize total cost of operating the combined wellfield-storage-demand system over the course of a 2-year planning period based on a time series of observed price on the Danish power market and a deterministic, time-varying hourly water demand. In the SDP setup, hourly pumping rates are the decision variables. Constraints include storage capacity and hourly water demand fulfilment. The SDP was solved for a baseline situation and for four scenario runs representing different EFP-Q relationships and different maximum wellfield pumping rates."br/""br/"Savings were quantified as differences in total cost between the scenario and a constant-rate pumping policy. Minor savings up to 10% were found in the baseline scenario, while the scenario with constant EFP and unlimited pumping rate resulted in savings up to 40%. Key factors determining potential cost savings obtained by flexible wellfield operation under a variable power price regime are the shape of the EFP-Q relationship, the maximum feasible pumping rate and the capacity of available storage facilities."br

Performance evaluation of the hydrogen-powered prototype locomotive ‘Hydrogen Pioneer’

Scipedia content — Wed, 03 Feb 2021 16:05:04 +0100

The narrow-gauge locomotive ‘Hydrogen Pioneer’, which was developed and constructed at the University of Birmingham, was employed to establish the performance of a hydrogen-hybrid railway traction vehicle. To achieve this several empirical tests were conducted. The locomotive utilises hydrogen gas in a Proton Exchange Membrane Fuel Cell power-plant to supply electricity to the traction motors or charge the on-board lead-acid batteries. First, the resistance to motion of the vehicle was determined, then operating tests were conducted for the speeds 2 km h−1, 6 km h−1, 7 km h−1, and 10 km h−1 on a 30 m straight, level alignment resembling light running. The power-plant and vehicle efficiency as well as the performance of the hybrid system were recorded. The observed overall duty cycle efficiency of the power-plant was from 28% to 40% and peak-power demand, such as during acceleration, was provided by the battery-pack, while average power during the duty cycle was met by the fuel cell stack, as designed. The tests establish the proof-of-concept for a hydrogen-hybrid railway traction vehicle and the results indicate that the traction system can be applied to full-scale locomotives.

Document type: Article

AnaVANET: an experiment and visualization tool for vehicular networks

Scipedia content — Wed, 03 Feb 2021 16:01:06 +0100

International audience; The experimental evaluation of wireless and mobile networks is a challenge that rarely substitutes simulation in research works. This statement is even more evident in vehicular communications, due to the equipment and effort needed to obtain significant and realistic results. In this paper, key issues in vehicular experimental evaluation are analyzed by an evaluation tool called AnaVANET, especially designed for assessing the performance of vehicular networks. This software processes the output of well-known testing tools such as ping or iperf, together with navigation information, to generate geo-aware performance figures of merit both in numeric and graphical forms. Its main analysis capabilities are used to validate the good performance in terms of delay, packet delivery ratio and throughput of NEMO, when using a road-side segment based on IPv6 GeoNetworking.

Significant Reduction of Validation Efforts for Dynamic Light Functions with FMI for Multi-Domain Integration and Test Platform

Scipedia content — Wed, 03 Feb 2021 16:00:16 +0100

Modern advanced driver assistance systems (ADAS) provide a significant increase in comfort and safety. In many cases, a single vehicle, today, contains more than one assistance system, while the trend to use ADAS continues to grow. At the same time, the number of systems that perform control interventions with safety-relevant functions increases as well. From an overall perspective, it must be assured that the driver assistance systems – individually as well as in the way they interact – function flawlessly in any driving situation and with any driver at the wheel anywhere in the world. This results in an increased development and testing effort for modern ADAS in general. In-development testing based on virtual test driving offers an approach to a solution that allows the validation effort to be significantly reduced while meeting the requirements for safetyrelevant functions in the vehicle associated with ISO 26262. This is particularly evident when developing and testing new light functions, which in real-world road tests can often be performed only in conditions of darkness. Dynamic Light Functions are defined as the situation-dependent headlight adjustment consisting of cornering light, headlight leveling and (glare-free) headlight assistance. This paper presents this new methodology.

Panoramic stitching for driver assistance and applications to motion saliency-based risk analysis

Scipedia content — Wed, 03 Feb 2021 15:54:09 +0100

Cameras can provide the capability for surround vehicle analysis and intuitive visualization for driver support in critical situations. As salient objects can be distributed anywhere around the vehicle, a wide view of the surround has many benefits for studying driver behavior in a holistic manner, as well as developing effective driver assistance systems. In this work, we are concerned with the hardware setup and calibration needed to provide such stitched views. In particular, views with large translation differences, many moving objects, and large changes in brightness are handled. We show the qualitative effects of calibration scene and camera orientation on common stitching algorithms. Finally, we analyze the stitched view for salient objects to detect critical events.

Real-time route diversion control at congested off-ramp areas -Part II: Route guidance versus off-ramp closure

Scipedia content — Wed, 03 Feb 2021 15:46:18 +0100

Summarization: This paper investigates the application of real-time route diversion policies, with or without off-ramp closure, to address recurrent motorway traffic congestion created due to a saturated off-ramp. In particular, the proposed route diversion policies attempt to avoid the off-ramp queue spill-over onto the motorway mainstream and the resulting motorway congestion by re- routing the motorway vehicles through nearby off-ramps towards the same destination. This paper addresses the case where real-time route guidance strategies, based on user-optimum considerations, are not sufficient to resolve the spill-over and motorway congestion problem, which may call for harsh measures (off-ramp closure) to force route diversion; while other cases are treated in a companion paper. The proposed route diversion concepts are tested for a hypothetical, but quite typical network infrastructure and traffic scenario by use of macroscopic simulation. The obtained simulation results are compared to the case where no route diversion is employed, and reveal interesting features and the potential for significant improvements. Παρουσιάστηκε στο: 16 th Meeting of the EURO Working Group on Transportation

Detection of Vulnerable Road Users in Smart Cities

Scipedia content — Wed, 03 Feb 2021 15:43:29 +0100

Starting from 2008, more than half of the world's population now lives in urban areas, and this number is expected to grow for the next decades. To the extent that the population of a city grows, new problems arise, which include scarcity of resources, pollution, and traffic congestion. One of the most important problems of big cities are road traffic injuries, which is the eighth leading cause of death globally, and the main cause of death for young people, mainly in middle and low income countries. Vulnerable road users (VRUs) are among the users at higher risks of traffic accidents. In order to cope with the problems of the growing urban communities, the concept of smart cities has emerged. A smart city is based on the use of smart computing technologies, such as Intelligent Transportation Systems and Vehicular Ad hoc Networks. In this paper, we propose a model to be used in smart cities, to detect if a VRU intends to cross a road in a risky zone, and to issue alerts to the vehicles nearby. The proposed model is cost effective, and is able to detect a VRU at risk in a short period of time. The evaluation of the proposed model shows that it performs correctly.

Informal public transport in Sub-Saharan Africa as a vessel for novel Intelligent Transport Systems

Scipedia content — Wed, 03 Feb 2021 15:43:18 +0100

Developed countries have lead the way in the implementation of Intelligent Transport Systems, with the objectives of improving safety, efficiency, and environmental impact of transport. With the developing world entering the fray, the questions are: Is ITS in its current form relevant to the developing world? These regions face challenges that are different to that of the developed world, and are unique in their own ways. Many of the regions are evolving novel and innovative solutions to deliver on ITS objectives. In this paper we explore the informal public transport sector in Sub- Saharan Africa, which is in many ways unique to that of the developing world. We highlight some of the unique aspects, and highlight the dire safety and efficiency challenges that the sector faces. Mindful of the regional limitations, we introduce and discuss novel ITS solutions, which can be used to address these challenges. We also share some of the initial results observed through initial experimentation with one of the solutions.

Development of real-time pipeline management system for the prevention of accidents

Scipedia content — Wed, 03 Feb 2021 15:41:52 +0100

Recently the importance of the management technologies for prevention increases. There are many kinds of pipelines under the ground of cities which have pipelines for waterworks, wastewater, oil, gas, electronic power, communications, heat energy, and so on. And these underground pipelines have different roles in supply the essential resources for citizens of cities and will be more important for citizens increasingly. So we call these pipelines as "LifeLine." By the way, these pipelines do not support their core roles to citizens and we can easily see that pipeline accidents have given inconvenient facts or serious man-made disasters to modern citizens as well. For examples, road settlement and sinkholes, waterworks leaks, pollutions by wastewater and oil, explosions by gas, and so on. Nowadays, we live in times using ICT - sensor technologies. So these environments have been advanced and are probably possible to resolve pipeline management problems using them beforehand in real time. Thus, ICT convergences will encourage us to make new technologies and paradigms on the field of pipeline management.

Interactions gestuelles pour Strip’TIC, un environnement tangible pour les contrôleurs aériens

Scipedia content — Wed, 03 Feb 2021 15:39:29 +0100

International audience; In this paper, we explore gesture-based interactions in a mixed interactive system for Air Traffic Controllers. This exploration lies on an analysis of controller gestures, that we were able to observe in a control tower and in a simulator centre. In our design, we focus on gesture-based interaction for the virtual objects associated with the physical objects.; Dans cet article nous décrivons une exploration des possibilités ouvertes par l’interaction gestuelle dans un système interactif mixte pour les contrôleurs aériens. Cette exploration repose sur une analyse des gestes des contrôleurs que nous avons pu observer en tour de contrôle et en simulateur. La conception exploratoire que nous proposons nous permet en particulier d'évaluer la pertinence de l’interaction gestuelle pour les objets virtuels associés aux objets physiques.

A hardware prototype for integration, test and validation of avionic networks

Scipedia content — Wed, 03 Feb 2021 15:35:06 +0100

Based on the current state-of-the-art in avionics, the adoption of new networking technologies and their integration into complex systems requires important efforts to guarantee the respect of system level requirements. This sets a need for a more effective and systematic approach to validate new technological choices and their integration process. In this paper, we propose a hardware prototyping platform for validating the design of an avionic transducers network in an early development stage. The specific implementation reported in this paper targets two boards based on a Spartan-6 LX45T Xilinx FPGA. Both boards were configured to validate a custom transducers network architecture proposed by the authors. The resulting prototype is configured to maintain a throughput of at least 1 Mbit/s and to guarantee a deterministic traffic on the field bus to conform to actual avionic constraints. This paper covers the methodology involved in the design of our prototyping platform and highlights some of the advantages it offers.

Ultrasonic inspection of adhesive joints of composite pipelines

Scipedia content — Tue, 02 Feb 2021 08:46:23 +0100

Composite pipelines are an attractive solution when traditional materials are not suitable for this purpose, which happens frequently at aggressive environments and also where the structural weight is a limiting factor. This work studies the application of the ultrasonic technique at the detection of defects as lack of adhesive and lack of adhesion, commonly found in adhesive joints of glass fiber reinforced plastic (GFRP) pipelines applied at onshore and offshore facilities. Computational simulations were conducted in CIVA 11© software (beta version) in order to obtain the best possible configuration for the inspections, applying the pulse-echo technique. Experimental results were compared to these simulations and several transducers were tested. An inspection methodology and reference blocks were developed for the calibration of the inspections. Some samples were selected for cutting in order to compare the ultrasonic results and the real condition of the joints. Results show that smaller frequencies ar...

SocialCycle what can a mobile app do to encourage cycling?

Scipedia content — Tue, 02 Feb 2021 08:46:09 +0100

Traffic congestion presents significant environmental, social and economic costs. Encouraging people to cycle and use other forms of alternate transportation is one important aspect of addressing these problems. However, many city councils face significant difficulties in educating citizens and encouraging them to form new habits around these alternate forms of transport. Mobile devices present a great opportunity to effect such positive behavior change. In this paper we discuss the results of a survey aimed at understanding how mobile devices can be used to encourage cycling and/or improve the cycling experience. We use the results of the survey to design and develop a mobile app called SocialCycle, which purpose is to encourage users to start cycling and to increase the number of trips that existing riders take by bicycle.

A survey on impacts of bike-oriented policies on residents and economic activities

Scipedia content — Tue, 02 Feb 2021 08:38:39 +0100

Fighting against the “car only” nature of towns, the bicycle has been gaining constant ground in the urban space since the 1970s. Much more than just a sport or leisure accessory, it has become a simple and efficient means of transport that, today, is an integral part of mobility services. The bicycle is ideal for short daily journeys, lends itself well to intermodality and is at the heart of sustainable development policy. For its user, it is practical, cheap, green and good for one’s health; for the countries that have adopted it, developing cycleable infrastructures, it has almost always been successful. The success can be measured by the many impacts on residents and activities and it is related to a correct design of the bike network and services. A conflicting example can be considered the bike lane inaugurated on the 10th November 2012 in the city of Napoli (Italy). It was introduced without simulating it with a proper decision support system (DSS) in order to evaluate the possible impacts on the users or on non-users (externalities), like congestion, parking problems, impacts on the local economy and without first involving the stakeholders for their feedback before its realization. To analyse the effects of the bike lane on activities, residents and mobility choices, two different revealed preference surveys have been carried out. A large part of respondents was sensitive to sustainable mobility and to the policy adopted by local authority. Both residents and retailers underlined the lack of parking spaces due to the bike lane and, as a consequence, a reduction of the turnover has been declared by retailers. Beneath bike mode is not considered nowadays as a valid alternative to car and public transport, a relevant increase in its use can be expected by surveys if right measures will be implemented.

A Stream Algebra for Computer Vision Pipelines

Scipedia content — Tue, 02 Feb 2021 08:33:49 +0100

Recent interest in developing online computer vision algorithms is spurred in part by a growth of applications capable of generating large volumes of images and videos. These applications are rich sources of images and video streams. Online vision algorithms for managing, processing and analyzing these streams need to rely upon streaming concepts, such as pipelines, to ensure timely and incremental processing of data. This paper is a first attempt at defining a formal stream algebra that provides a mathematical description of vision pipelines and describes the distributed manipulation of image and video streams. We also show how our algebra can effectively describe the vision pipelines of two state of the art techniques.

Limit Bending Capacity of Steel Pipes Considering Strain Hardening Effect

Scipedia content — Tue, 02 Feb 2021 08:26:11 +0100

Based on Hencky's total strain theory of plasticity, the limit bending capacity of steel pipes can be determined analytically assuming an elastic-linear strain hardening material. The simplified analytical solution is proposed as well. Good agreement is observed when limit bending capacities obtained from analytical solutions are compared with experimental results from full-size testing of steel pipes. It is shown that pipe considered to be strain hardening yields a higher bending capacity than that of pipe assumed as an elastic-perfectly plastic material. Thus, the ignorance of strain hardening effect, as commonly assumed in current codes, may underestimate the limit bending capacity of steel pipes. The solutions proposed in this paper are applicable in the design of offshore and onshore steel pipes, supports of offshore platforms and other tubular structural steel members.

Removable battery packs to remove air pollution in Paris : economic evaluation through the CoBAYe decision-making tool

Scipedia content — Tue, 02 Feb 2021 08:24:29 +0100

International audience

Optimizing components size of an extended range electric vehicle according to the use specifications

Scipedia content — Tue, 02 Feb 2021 08:23:07 +0100

Transport Research Arena (TRA) 5th Conference: Transport Solutions from Research to Deployment, PARIS, FRANCE, 14-/04/2014 - 17/04/2014; This paper presents a methodology to optimally design the drivetrain of an Extended Range Electric Vehicle (EREV) according to the use specifications from European mobility surveys. At first the analysis of car uses is carried out, and a process aiming to classify the car use profiles into different clusters is proposed. Clusters that could fit typical EREV use are selected and applied in a sizing methodology to design the battery and the Range Extender (RE). Using a validated simulation software, the proposed method takes into account the range requirements of the car use profile, its energy consumption, realistic driving cycles from European database and battery aging. Combined with a simple Total Cost of Ownership (TCO) model, the most cost effective solution is determined, depending on the performance required. The results show that EREVs might be an interesting solution to consider, as they could lead to a significant TCO reduction (-17%) while offering twice as much range as currently available Battery-only Electric Vehicles (BEVs).

Assessing the consistency between observed and modelled route choices through GPS data

Scipedia content — Tue, 02 Feb 2021 08:15:18 +0100

In traffic engineering, different assumptions on user behaviour are adopted in order to model the traffic flow propagation on the transport network. This paper deals with the classical hypothesis that drivers use the shortest possible path for their trip, pointing out the error related to using such approximation in practice, in particular in the context of dynamic origin-destination (OD) matrix estimation. If this problem is already well known in the literature, only few works are available, which provide quantitative and empirical analysis of the discrepancy between observed and modelled route sets and choices. This is mainly related to the complexity of collecting suitable data: to analyse route choice in a systematic way, it is necessary to have observations for a large period of time, since observing trajectories for the single user on a specific day could not be enough. Information is required for several days in order to analyse the repetitiveness and understand which elements influence this choice. In this work the use of the real shortest path for a congested network is evaluated, showing the differences between what we model and what users do. Results show that there is a systematic difference between the best possible choice and the actual choice, and that users clearly consider route travel time reliability in their choice process.

Lightweight Location Verification in Air Traffic Surveillance Networks

Scipedia content — Tue, 02 Feb 2021 08:05:59 +0100

In this work, we develop a realistic threat model for attacks on modern air traffic communication networks and show that current state-of-the-art countermeasures such as multilateration are insufficient. We propose two alternatives, a statistical location verification technique and a grid-based location estimation approach, to deal with the identified threats. We evaluate our proposals using real-world flight data and quantify their effectiveness in terms of aircraft location accuracy, resilience to message injection attacks, attack detection speed, and surveillance coverage. Our results show that the statistical verification approach can increase the effective air traffic surveillance coverage compared to multilateration by a factor of more than 100. Concerning our location estimation method, we find that the mean aircraft location accuracy can be increased by up to 41% in comparison with multilateration while also being able to pinpoint ground-based attackers with a mean error of 145m for air-based attackers. Finally, we demonstrate that our proposal is lightweight as it does not require any changes to the existing air traffic protocols and transmitters, and is easily implemented using only low-cost hardware.

Human detection in uncluttered environments: From ground to UAV view

Scipedia content — Tue, 02 Feb 2021 08:00:57 +0100

International audience; Nowadays pedestrian detectors are fast, scale-robust and quite efficient. Embedded within a UAV such a detector would open new possibilities. In this paper the very well known HOG detector is adapted for UAV use and a new kind of training dataset is proposed in order to increase the detector's angular robustness. A more appropriate set of detection windows, together with a new detection pipeline, is proposed in order to reduce the search space and consequently reduce the computation time. Tests conducted using the improved detector show significantly better results on aerial images.

Implementation and Performance of Probabilistic Inference Pipelines

Scipedia content — Tue, 02 Feb 2021 07:56:04 +0100

In order to handle real-world problems, state-of-the-art probabilistic logic and learning frameworks, such as ProbLog, reduce the expensive inference to an efficient Weighted Model Counting. To do so ProbLog employs a sequence of transformation steps, called an \\emph{inference pipeline}. Each step in the probabilistic inference pipeline is called a \\emph{pipeline component}. The choice of the mechanism to implement a component can be crucial to the performance of the system. In this paper we describe in detail different ProbLog pipelines. Then we perform a empirical analysis to determine which components have a crucial impact on the efficiency. Our results show that the Boolean formula conversion is the crucial component in an inference pipeline. Our main contributions are the thorough analysis of ProbLog inference pipelines and the introduction of new pipelines, one of which performs very well on our benchmarks. ispartof: pages:90-104 ispartof: Practical Aspects of Declarative Languages vol:9131 pages:90-104 ispartof: Practical Aspects of Declarative Languages location:Portland, Oregon, USA date:18 Jun - 19 Jun 2015 status: published

A New Heuristic Providing an Effective Initial Solution for a Simulated Annealing approach to Energy Resource Scheduling in Smart Grids

Scipedia content — Tue, 02 Feb 2021 07:53:13 +0100

n intensive use of dispersed energy resources is expected for future power systems, including distributed generation, especially based on renewable sources, and electric vehicles. The system operation methods and tool must be adapted to the increased complexity, especially the optimal resource scheduling problem. Therefore, the use of metaheuristics is required to obtain good solutions in a reasonable amount of time. This paper proposes two new heuristics, called naive electric vehicles charge and discharge allocation and generation tournament based on cost, developed to obtain an initial solution to be used in the energy resource scheduling methodology based on simulated annealing previously developed by the authors. The case study considers two scenarios with 1000 and 2000 electric vehicles connected in a distribution network. The proposed heuristics are compared with a deterministic approach and presenting a very small error concerning the objective function with a low execution time for the scenario with 2000 vehicles.

HMAX Image Processing Pipeline with Coupled Oscillator Acceleration

Scipedia content — Tue, 02 Feb 2021 07:51:50 +0100

In this paper we report on the performance of a coupled oscillator based implementation of the HMAX image-processing pipeline. Within this pipeline we have used coupled oscillator arrays to replace traditional Boolean logic with a Degree-of-Match (DoM) function that measures the L2 distance squared between two vectors in an n-dimensional space. We show that this operation can be used in three stages of the pipeline: 1) as a substitute for convolution in filtering operations, 2) as a computational kernel for pattern matching, and 3) as a distance function in a nearest neighbor classification algorithm. In this study, we have modeled the performance of the latter two and report our recognition results over a test set from the Neo Vision2 image database.

Accessibility in a post-apartheid city: Comparison of two approaches for the computation of accessibility indicators

Scipedia content — Tue, 02 Feb 2021 07:50:11 +0100

y indicators take land use, the transport system, and their interdependencies into account in a holistic fashion. In many areas, however, spatial data to perform accessibility calculations are hard to obtain or not available at all. Freely available volunteered geographic information (VGI) like from OpenStreetMap (OSM), which is increasingly becoming a world-wide standard for geo-spatial data, may be a solution to this problem. In fact, some accessibility studies use data from OSM to create representations of the transport network and to perform network-based computations. In this paper, two approaches for accessibility assessment for Nelson Mandela Bay Municipality in South Africa are presented. The approaches possess different levels of utilization of OSM data which both exceed the use of OSM data for network creation. In the first approach, the transport network as well as locations and types of activity facilities are taken from OSM. Additionally, a synthetic population is created based on a census. The corresponding travel demand is generated based on a travel survey. Local expert knowledge is applied to design a household-specific accessibility indicator that takes into account various characteristics of travel and land use, such as travel time to work and/or education, travel time to the nearest health/shopping facility, availability of different transport options, and availability of various facilities within walking distance. Weights are used to combine the respective values of aforementioned characteristics into a composite, household-based accessibility score. This approach appears particularly suitable in the South African context where housing locations and travel characteristics are highly diverse among the population. The second approach relies exclusively on OSM data, which is -- as before -- used to create the network and activity facilities in the model. The approach applies an econometric accessibility indicator, which calculates the accessibility of a given measuring point as the weighted sum over the utilities of all opportunities including the costs of reaching them. In contrast to the first approach, no synthetic population, but only household locations -- collected from OSM in the same way as (other) activity facilities -- are used for the calculation. The approach is highly portable since no input data other than those from OSM are used. It is found that the second approach, though being much more lightweight in terms of data requirements, yields the same quality of insights concerning accessibilities of different areas of the region. Both approaches detect areas where levels of accessibility deprivation are high and where interventions in the transport-land-use system are advisable. Consequently, the paper is a contribution to accessibility analyses based on easily obtainable and ubiquitously available OSM data to obtain similar results as with respective approaches based on traditional spatial data.

From Virtual to Reality, How to Prototype, Test and Evaluate New ADAS: Application to Automatic Car Parking

Scipedia content — Tue, 02 Feb 2021 07:42:42 +0100

Over the past decade, a lot of researches have been done on the development of advanced driver assistance systems (ADAS). Most of these ADAS are now active and need to be tested and evaluated before large deployment. In these ADAS, the prototyping and the implementation of the control stages are risky stages and not so easy to carry out. Indeed, the prototyping and the test of such reactive algorithms need heavy hardware and software supports (dedicated vehicle, actuators, hardware architecture, software architecture, sensors). To achieve such active devices, additional developments and implementation of numerous expensive embedded devices are required. Therefore, in order to reduce both time and risk, in early design stage, it becomes necessary to have a very realistic simulation environment dedicated to the development and to the evaluation of these ADAS. For such virtual platform, it is mandatory to provide physics-driven road environments, virtual embedded sensors, and physics-based vehicle models. In this publication, we present a dedicated couple of platforms with their efficient interconnection for the prototyping of such ADAS. Initially, the SiVIC simulation platform has been developed to generate the virtual world (environments, sensors, actuators, vehicles). In order to improve the real time prototyping capabilities of SiVIC, an efficient interconnection of this first platform has been done with RTMaps platform. This second one is mainly dedicated to the multi-sensors data processing (data management, fusion, flow recording and replaying). In this paper we will show the interest of such bi-directionnal interconnected platforms to prototype complex and real time embedded ADAS. This interconnection can be done as well on an only one computeur than on a distributed and distant computers architecture. The relevance of this approach will be illustrated with an automatic parking application.

Enhancing Liquid Hydrocarbon Pipeline Leak Detection Using Instrumented Aerial Surveillance

Scipedia content — Tue, 02 Feb 2021 07:41:18 +0100

Suncor Energy Inc. contacted Synodon as part of an effort to enhance pipeline leak detection. Ideally, Suncor needed a technology that could detect natural gas as well as liquid hydrocarbon releases. Synodon’s new technology is an aircraft mounted gas remote sensing instrument that has been used for detecting leaks from natural gas pipelines for over four (4) years and was expanding their capability to include liquid hydrocarbons."/jats:p" "jats:p"This paper will describe the steps that Suncor and Synodon have taken over the last two years to develop and validate this detection technology. Synodon completed a number of studies including laboratory and field tests that demonstrated the ability of Synodon’s technology to remotely detect ground-level plumes of vapours released from a liquid hydrocarbon pipeline."/jats:p" "jats:p"Synodon conducted full atmospheric analytic modeling followed by laboratory measurements to determine the level of sensitivity of its instrument measurement to both methane and various liquid hydrocarbon vapors including gasoline, condensates and synthetic crude oil. Suncor participated in the development of test methodology and field execution in order to witness and validate the results."/jats:p" "jats:p"Based on this work, Suncor has determined an optimum inspection frequency based on theoretical spill size, SCADA leak detection thresholds and conventional aerial patrol constraints."/jats:p" "jats:p"The results and conclusions of this work will be presented.

Acoustic Reflectometry for Blockage Detection in Pipeline

Scipedia content — Tue, 02 Feb 2021 07:29:49 +0100

Flow assurance is an important aspect of offshore, particularly deepwater pipeline design and operation, since one of the critical issues is the eventual initiation and growth of hydrate or paraffin blockages under certain conditions. Ideally, operators would benefit from online information regarding position and extent of an eventual blockage in a pipeline. The aim of this work is to apply acoustic technology to design and make a prototype that can be used in a pipe to efficiently identify and measure blockages. The technique uses a short duration sound pulse that is injected into the pipe. When the acoustic pulse encounters an impedance discontinuity, a portion is reflected back towards the acoustic source and microphones or hydrophones. Analysis of the measured signal reflections can provide valuable data related to location and size of the blockages. An experimental setup with a pipe of 4″ internal diameter and length of 100 m was constructed, and different excitation signals for the impulsive response function measurements were conducted. Microphones and hydrophones measurements were recorded using a fit-for-purpose data acquisition system with sampling rates of up to 1kS/s per channel. The tests were performed in air and water using different sizes of blockages and in different positions in the pipe. In parallel, finite element analyses were performed using the commercial software Abaqus to simulate the same conditions. The experiments were numerically reproduced with good correlation proving the potential of the technique.Copyright © 2014 by ASME

Calculation of flight deck interval management assigned spacing goals subject to multiple scheduling constraints

Scipedia content — Tue, 02 Feb 2021 07:16:10 +0100

The Federal Aviation Administration's Next Generation Air Transportation System will combine advanced air traffic management technologies, performance-based procedures, and state-of-the-art avionics to maintain efficient operations throughout the entire arrival phase of flight. Flight deck Interval Management (FIM) operations are expected to use sophisticated airborne spacing capabilities to meet precise in-trail spacing from top-of-descent to touchdown. Recent human-in-the-loop simulations by the National Aeronautics and Space Administration have found that selection of the assigned spacing goal using the runway schedule can lead to premature interruptions of the FIM operation during periods of high traffic demand. This study compares three methods for calculating the assigned spacing goal for a FIM operation that is also subject to time-based metering constraints. The particular paradigms investigated include: one based upon the desired runway spacing interval, one based upon the desired meter fix spacing interval, and a composite method that combines both intervals. These three paradigms are evaluated for the primary arrival procedures to Phoenix Sky Harbor International Airport using the entire set of Rapid Update Cycle wind forecasts from 2011. For typical meter fix and runway spacing intervals, the runway- and meter fix-based paradigms exhibit moderate FIM interruption rates due to their inability to consider multiple metering constraints. The addition of larger separation buffers decreases the FIM interruption rate but also significantly reduces the achievable runway throughput. The composite paradigm causes no FIM interruptions, and maintains higher runway throughput more often than the other paradigms. A key implication of the results with respect to time-based metering is that FIM operations using a single assigned spacing goal will not allow reduction of the arrival schedule's excess spacing buffer. Alternative solutions for conducting the FIM operation in a manner more compatible with the arrival schedule are discussed in detail.

Curved-Wide Plate Testing of X100 Girth Welds

Scipedia content — Tue, 02 Feb 2021 06:56:43 +0100

Curved-wide plate (CWP) tests are frequently used for assessing the quality of pipeline girth welds. Despite a large number of CWP tests having been conducted at great expense over many decades, an industry consensus standard remains unavailable. Considerable effort at several research institutions is focused on the standardization of test protocols. It is widely recognized that comparing results from CWP tests from different institutions is difficult without accounting for all the possible parametric differences."/jats:p" "jats:p"This paper presents the procedural details recently used in testing X100 girth welds. The protocols cover (1) specimen design and dimensions, (2) instrumentation plan and data acquisition, (3) specimen fabrication and preparation, (4) preparing and executing the tests, (5) processing of raw test data and (6) post-test metallurgical examination."/jats:p" "jats:p"The evaluation of specimen deformation, flaw growth, and comparison of test data with model predictions will be presented in a future paper. Selected CWP test data from this program were evaluated and compared to tensile strain models of the girth welded pipe in a recent paper [1].

Enhancing Resilience in European Air Traffic Passenger and Freight Transport

Scipedia content — Tue, 02 Feb 2021 06:43:15 +0100

viation-Beitrag zur Berliner Abschlusskonferenz des FP7 Projektes MOWE-IT

Protection of Pipelines and Buried Structures Using EPS Geofoam

Scipedia content — Tue, 02 Feb 2021 06:35:23 +0100

Expanded Polystyrene (EPS) geofoam is a lightweight, compressible material that can be used to protect buried infrastructure in areas with high to moderate seismicity. This paper summarizes recent research conducted at the University of Utah regarding the seismic design and construction of EPS geosystems to improve the seismic resiliency of pipelines and buried structures, particularly at normal fault crossings. It discusses the development and verification of an EPS cover/backfill system to protect buried pipelines and other structures from potential rupture caused by permanent ground deformation (e.g., tectonic faulting, subsidence, liquefaction, land sliding, etc. Full-scale experiments and numerical modeling show that a light-weight cover system constructed, in part, with EPS block offers significant benefits in protecting buried pipelines from the damaging effects of offset caused by permanent ground deformation. The prototype EPS cover system significantly reduced the vertical uplift force and stresses imposed on the buried pipe system as it was subjected to uplift through the EPS cover system.

Intermodal transportation perspectives in South Africa: a case study of its application within the Gauteng Province and lessons learned for other metropolitan areas

Scipedia content — Tue, 02 Feb 2021 06:28:20 +0100

Gauteng Province is located in the northern part of the South African national spatial system and is bordered by the Free State, North West, Limpopo and Mpumalanga Provinces. It is the smallest geographically of all the provinces, but the largest in terms of population and its contribution to the country’s GDP. Originally, Gauteng Province developed on the wealth of gold (40% of the world’s reserves). The economy has since diversified to more sophisticated sectors, such as finance, manufacturing, transport and telecommunications. It forms the economic engine of the Southern African region and the gateway to doing business in the rest of Africa. The study area is the smallest of the nine provinces, but contributes more than 30% to the national economy and 10% to the African economy. Due to the locational factors the study area is currently fulfilling a primary role in the growth and development of the national economy and its spatial development. This also applies to development within the Africa continental spatial system. The Gauteng Provincial Government in 2013 published the Gauteng Integrated Transport Master Plan (GITMP). In this plan consideration is given to the promotion of intermodal transportation development. The purpose of this paper is to assess the intermodal transport perspectives within the Gauteng Province and to relate it to the strategies as formulated in the National Development Plan (2012) for NATMAP 2050 for the national spatial system. The paper focuses on the use of specific planning and development instruments to promote sustainable transportation planning and development. It’s guiding giving influence and impacts on intra traffic movements through process linkages and alignment between strategy and implementation approaches are investigated. The findings will serve as a guideline to follow in application of similar strategy, planning and implementation approaches within other provincial spatial systems.

Seismic Design of Buried Steel Water Pipelines

Scipedia content — Tue, 02 Feb 2021 06:27:16 +0100

The present paper provides an overview of available tools and provisions for the structural analysis and design of buried welded (continuous) steel water pipelines in seismic areas, subjected to earthquake action. Both transient and permanent ground actions (coming from tectonic faults, landslides and liquefaction-induced lateral spreading) are considered. Specific issues are discussed on the modelling of the interacting pipeline-soil system using either simple analytical models or nonlinear finite elements, and their main advantages and disadvantages are pin-pointed. Subsequently, the resistance of buried pipelines is discussed, with emphasis on possible failure modes. Finally, possible mitigations measures for reducing seismic effects are discussed, for the safe operation of steel water pipelines against seismic hazard.

Regulatory Next Steps in Addressing Pipeline Seam Weld Challenges

Scipedia content — Tue, 02 Feb 2021 06:24:25 +0100

Since the beginning of pipeline transportation operations, pipe seam integrity and mitigation measures to prevent pipe seam leaks and failures have been a challenge for the industry and government regulators. The Pipeline and Hazardous Materials Safety Administration’s (PHMSA) Office of Pipeline Safety (OPS) has investigated leaks and failures, issued advisory bulletins, funded research projects, and developed regulations for integrity assurance of pipe seams during pipeline design, construction, and operations and maintenance (including integrity management)."/jats:p" "jats:p"This report will discuss PHMSA’s pipe seam efforts to date, framing leak and failure history, past advisory bulletins, United States (U.S.) Legislative and Executive actions (statutory actions), recent U.S. National Transportation Safety Board (NTSB) findings, accident investigation findings, and ongoing research for pipe long seam welds. PHMSA will review challenges and summarize past and possible future regulatory considerations based on the research findings to date and pipe seam incidents."/jats:p" "jats:p"In 2011 PHMSA initiated a long seam research project titled “Comprehensive Study to Understand Longitudinal ERW Seam Failures.” The program goals are to assist PHMSA in favorably closing U.S. NTSB Recommendations P-09-01 [1] and P-09-02 [1], which were issued after the Carmichael, Mississippi pipeline electric resistance welded (ERW) seam rupture, and recommended that PHMSA conduct a comprehensive study of ERW pipe properties and implement measures to assure that they do not fail in service."/jats:p" "jats:p"The research objectives for Phase 1 were to review current ERW seam integrity assessment methods (hydrostatic testing and in-line inspection using a crack-detection tool) to understand measures needed to consistently identify subcritical seam defects in order to act in time to prevent ERW seam ruptures. Phase 2 objectives are to develop hydrotest protocols, improve anomaly characterization criteria, develop seam defect growth models, and develop seam integrity management techniques. Phase 1 was completed in early January 2014, and Phase 2 is scheduled to be completed in late fall 2014. To date, this study has led to 17 technical reports. These reports are publically available on the following PHMSA website: http://primis.phmsa.dot.gov/matrix/PrjHome.rdm?prj=390.

Mathematical models for the best water usage strategy

Scipedia content — Tue, 02 Feb 2021 06:13:37 +0100

In this paper, we investigate the best water usage strategy problem of China. Firstly, based on the historical date from 2004 to 2012, we forecast the fresh water supply and demand in each province in the near future by GM(1,1) model. Then we calculate the supply-demand gap and the pure fresh water surplus in each province, and partition all provinces into water-supplying provinces and water-demanding provinces according to their signs of pure fresh water surplus. We formulate the problem into a linear programming model and a mix integer linear programming model respectively. The total costs in each model are calculated by the data of 2012. The total costs obtained from the mix integer linear programming model are 18680.59 billion yuan, which are 51883.53 billion yuan less than that obtained by the linear programming model. The results show that we can reduce the total costs of water usage by using multiple methods including pipeline transportation, desalinization and conservation etc.

A sustainable urban logistics dashboard from the perspective of a group of logistics managers

Scipedia content — Tue, 02 Feb 2021 06:04:49 +0100

Urban logistics has now become a priority issue in both supply chain management and urban planning. However, the different stakeholders involved develop different approaches whose aims and objectives do not always coincide and sometimes present conflicting standpoints. The aim of this paper is to complete existing literature by proposing a sustainable dashboard for evaluating the sustainable performance of urban delivery systems, from the perspective of operational logistics managers, one of the categories of stakeholders given less consideration by public authorities in their quest for consensus. First, a synthesis of the main works on the subject is proposed, in order to provide a common grid of economic, environmental and social/societal indicators for Sustainable Supply Chain Management, after which the method for defining the dashboard is presented. This method is derived from a collaborative decision-aid approach and applied to a panel of operational logistics managers. Next, the results of the analysis framework are presented, and the selected indicators proposed and commented. Finally, a model dashboard is presented and discussed, followed by conclusions and further developments in view to the practical application of the approach proposed.

Modelling eco-efficiency for vehicular emissions from the perspective of Dhaka city: development of a tool for sustainable transport planning

Scipedia content — Tue, 02 Feb 2021 05:51:08 +0100

Development in the transport sector can achieve sustainability when efficiency in service and emissions reduction is ensured. The objective of this research was thus to generate scenarios of pollution and green house gas (GHG) levels at different states of the transport system in Dhaka City, Bangladesh, along with assessing its efficiency level. The innovative idea encompassed in this research is in developing a model based on the relationships developed with the system parameters, capable of dealing with a system provided with very detailed data of the parameters or with a limited data set, to assess transport eco-efficiency of a city with a similar urban structure. This eco-efficiency approach can create new opportunities for rapidly motorizing cities in developing countries (such as Dhaka City) for the purpose of appraising the performance of their transport system in attaining increased environmental efficiency through policy and/or strategic planning modifications to the road network and land use. Refereed/Peer-reviewed

Concept Maps for Integrating Modeling Techniques for the Analysis and Re-Design of Partly-Autonomous Interactive Systems

Scipedia content — Tue, 02 Feb 2021 05:41:59 +0100

Socio-Technical Systems (STS) such as Air Traffic Management Systems (ATM) are considered as complex as they encompass interactions involving humans and machines deeply influenced by environmental aspects (e.g. weather conditions) and by the overall organizational structure in which they are deployed in. Within such STS, interactive systems are omnipresent allowing operators to interact with the underlying system. Such interactive systems must be both usable (i.e. enabling users to perform their tasks efficiently and effectively while ensuring a certain level of operator satisfaction) and resilient to adverse events including software malfunctions (e.g. automation degradation) as well as interaction related problems (e.g. human errors or interactive system failures). Current techniques, methods and tools do not allow to model STSs as a whole and thus to analyze both usability and resilience properties. This paper proposes a multi-models based approach for the modelling and the analysis of partly-autonomous interactive systems for assessing their resilience and usability. The approach integrates 3 modelling techniques: Functional Resonance Analysis Method (FRAM) (focused on organizational functions), Human-centered Assessment and Modelling to Support Task Engineering for Resilient Systems (HAMSTERS) (centered on human goals and activities) and Interactive Cooperative Objects (ICO) (dedicated to the modelling of interactive systems). The principles of the multi-models approach is illustrated on an example for carefully showing the extensions proposed to the selected modelling techniques and how they integrate together. A case study dealing with aircraft route change due to bad weather conditions demonstrates the scalability and benefits of the approach.

Optimization of charging strategies for electric vehicles in PowerMatcher-driven smart energy grids

Scipedia content — Tue, 02 Feb 2021 05:14:59 +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 exibility 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 exibility 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.

Mobile Sensor Networks for Leak and Backflow Detection in Water Distribution Systems

Scipedia content — Tue, 02 Feb 2021 05:09:01 +0100

Leak and backflow detection are essential aspects of Water Distribution System (WDS) monitoring. Most existing solutions for leak/backflow detection in WDSs focus on the placement of expensive static sensors located strategically. In contrast to these, we propose a solution whereby mobile sensors (i.e., their movement aided only by the inherent water flow in the system) detect leaks/backflow. Information about the leaks/backflow is collected from the sensors either by physically capturing them, or through wireless communication. Specifically, we propose models to maximize leak/backflow detection given a cost constraint (a limit on the number of sensors). Through extensive simulations, we demonstrate the superior performance of our proposed solution when compared with the state of the art solutions (e.g., algorithms/protocols and analysis).

A framework for flight guidance along air streams

Scipedia content — Tue, 02 Feb 2021 05:01:49 +0100

International audience; With the current performances of aeronautical communication, navigation and surveillance systems, free flight and traffic management through trajectory negotiation become a reality. However, the adoption of free flight in congested airspace leads to an increase of the number of potential traffic conflicts which are solved by diverting aircraft from their original flight plan, limiting the benefits of free flight. In this paper it is proposed to organize traffic in congested airspace along main air streams which are characterized by a flyable 3D track for modern transportation aircraft. Then aircraft position can be given in a local space indexed cylindrical coordinates system which should ease the management of traffic separation and surveillance. This should result in the need to develop new 3D space indexed guidance modes to perform lateral trajectory tracking while insuring time separation between successive aircraft.

The sustainability of gravel roads as depicted by sub Saharan Africa’s standard specifications and manuals for road works: Tanzania case study

Scipedia content — Tue, 02 Feb 2021 04:55:07 +0100

The sustainability of gravel roads depends, among other things, on the appropriate locally formulated manual and standard specification. These regulating documents should not only address how best these roads could be brought into being but also address the environmental and climatic issues affecting or affected by gravel roads. To achieve that goal, these manuals and standard specifications have to ensure that during their design life, the gravel roads constructed are in harmony with the environment. In that period, the gravel roads should contribute less to the pollution and degradation of the environment and climatic changes. This can be achieved through properly documented mitigation procedures embedded during gravel roads design and construction and also during routine and periodic maintenance. This paper reviews what is specified in the Tanzania’s Pavements and Materials Design Manual (PMDM) and the Standard Specification for Road Works (SSRWs), in particular on environmental and climatic issues associated with the gravel roads construction and maintenance activities and mitigation measures adopted. The review results show that the Tanzania PMDM and SSRWs do not adequately address environment and climate issues affecting or being affected by gravel roads performance. This paper concludes by listing the appropriate measures expected to achieve gravel roads sustainability.

Looking-in and looking-out vision for Urban Intelligent Assistance: Estimation of driver attentive state and dynamic surround for safe merging and braking

Scipedia content — Tue, 02 Feb 2021 04:33:27 +0100

This paper details the research, development, and demonstrations of real-world systems intended to assist the driver in urban environments, as part of the Urban Intelligent Assist (UIA) research initiative. A 3-year collaboration between Audi AG, Volkswagen Group of America Electronics Research Laboratory, and UC San Diego, the driver assistance portion of the UIA project focuses on two main use cases of vital importance in urban driving. The first, Driver Attention Guard, applies novel computer vision and machine learning research for accurately tracking the driver's head position and rotation using an array of cameras. The system then infers the driver's focus of attention, alerting the driver and engaging safety systems in case of extended driver inattention. The second application, Merge and Lane Change Assist, applies a novel probabilistic compact representation of the on-road environment, fusing data from a variety of sensor modalities. The system then computes safe and low-cost merge and lane-change maneuver recommendations. It communicates desired speeds to the driver via Head-up Display, when the driver touches the blinker, indicating his desired lane. The fully-implemented systems, complete with HMI, were demonstrated to the public and press in San Francisco in January of 2014.

The Nanostructuring of the Functional Surface of the Oil Pipelines

Scipedia content — Tue, 02 Feb 2021 04:26:22 +0100

The current state of oil pipelines is characterized by decrease of operational reliability and efficiency which are caused by intensive corrosion processes and accumulation of asphaltens-resinous-wax formations on internal surfaces. Formation of accumulations is the reason of essential increase in hydraulic resistance of pipeline. The most suitable way for decrease of hydraulic resistance of oil pipelines is the modifying of internal surfaces at the expense of formation of molecular fluorine SAS layers. Nano-structural modification of internal surfaces is carried out at the expense of the focused adsorption of fluorine SAS molecules from the transported environment and formation so-called «a paling of Lengmjura». It is established that updating of internal surfaces of the pipeline at the expense of formation on them of molecular fluorine SAS layers leads to reduction of their hydraulic resistance on 30 ÷ 23 %. Molecular fluorine SAS layers, generated on a metal surface, considerably improves its hydraulic characteristics without dependence from roughness size. This peculiarity of molecular fluorine SAS layers allows not only to restore hydraulic resistance of the oil pipelines which have grown during of operating process, but also to improve their initial hydraulic characteristics. Characteristics of interaction of a stream of oil and an internal surface are optimized by nano-structural processing. The given technology allows to lower hydraulic resistance by changing the roughness of the internal surface of the pipeline, to lower power expenses for transportation of hydrocarbons raw materials, to raise operational reliability and to extend the between-repairs period.

Fault classification method for the driving safety of electrified vehicles

Scipedia content — Tue, 02 Feb 2021 04:09:24 +0100

fault classification method is proposed which has been applied to an electric vehicle. Potential faults in the different subsystems that can affect the vehicle directional stability were collected in a failure mode and effect analysis. Similar driveline faults were grouped together if they resembled each other with respect to their influence on the vehicle dynamic behaviour. The faults were physically modelled in a simulation environment before they were induced in a detailed vehicle model under normal driving conditions. A special focus was placed on faults in the driveline of electric vehicles employing in-wheel motors of the permanent magnet type. Several failures caused by mechanical and other faults were analysed as well. The fault classification method consists of a controllability ranking developed according to the functional safety standard ISO 26262. The controllability of a fault was determined with three parameters covering the influence of the longitudinal, lateral and yaw motion of the vehicle. The simulation results were analysed and the faults were classified according to their controllability using the proposed method. It was shown that the controllability decreased specifically with increasing lateral acceleration and increasing speed. The results for the electric driveline faults show that this trend cannot be generalised for all the faults, as the controllability deteriorated for some faults during manoeuvres with low lateral acceleration and low speed. The proposed method is generic and can be applied to various other types of road vehicles and faults. "p"QC 20140509. Updated from manuscript to article in journal"/p""p""/p""p"Funder: Swedish Hybrid vehicle Center

Protecting combinational logic in pipelined microprocessor cores against transient and permanent faults

Scipedia content — Tue, 02 Feb 2021 04:03:32 +0100

International audience; CMOS technology trends at one side open up some opportunities like making small and power efficient devices available, which in turn allow to put more functionality into a single chip. However, on the other side it poses some challenges like making devices vulnerable to hard and soft errors. In this paper we propose an efficient fault-tolerant architecture able to deal with permanent and transient faults in combinational parts of pipeline structures. The principle consists in triplicating the combinational logic parts but, unlike TMR, only two copies are running in parallel while the third one remains in standby until an error is detected. We implement this approach on a MIPS microprocessor as case study to make it resilient against transient and permanent faults.

The modelling of air supply system efficiency in refrigerated vehicles

Scipedia content — Tue, 02 Feb 2021 04:02:17 +0100

Inadequate air circulation within refrigerated truck chambers is one of the main causes of unsuitable road transport of perishable goods under controlled temperatures. An accurate understanding of indoor air motion is crucial to improving the cold conditions as well as increasing the energy efficiency of mechanical and electrical systems. This paper presents a computational model to predict the velocity, temperature and relative humidity fields in refrigerated truck chambers. The model consists of a computer procedure, in which the general equations describing the airflow pattern and the heat/mass transfer in a refrigerated room are solved using the finite volume method. The computer model was experimentally validated by measurements taken from a reduced-scale model designed to provide similarity with a prototype. The computational model was applied to calculate the cold quality, for example the temperature distribution, provided by different types of air supply systems used in compartments of long-haul vehicles. The results of the numerical solutions demonstrate how the model can be profitably used in practice to study and develop the design of refrigerated chambers.

Virtual network mapping for cloud services under probabilistic regional failures

Scipedia content — Tue, 02 Feb 2021 03:57:59 +0100

Network virtualization is critical for distributing cloud services over expanded distances and improving scalability and responsiveness. However many providers are very concerned about maintaining high availability, particularly under large catastrophic/disaster type conditions causing multiple failures. Now recent studies have looked at network virtualization for disaster recovery. However these efforts have only treated resourceintensive protection strategies and have not incorporated the probabilistic nature of disasters. Hence this paper studies virtual network embedding using a-priori failure state information and proposes various strategies based upon both traffic engineering (resource efficiency) and risk minimization (disaster mitigation) objectives. The performance of these schemes is tested using network simulation and future research directions identified.

First Impacts of ASEAN Liberalization on Regional Air Transport Markets : The case of Cambodia

Scipedia content — Tue, 02 Feb 2021 03:56:13 +0100

International audience; The ASEAN air transport liberalization was initiated in 2004. The objective for 2015 is to establish a relaxation of 3rd, 4th and 5th freedom rights between member states. 7th freedom and cabotage rights, which are necessary to a successfully completed single market, are not yet included but could be by 2023. Two multilateral air services agreements have been set up (MAAS and MAFLPAS), and will lead to this liberalization objective in January 2015. Nevertheless, ASEAN countries can already decide to implement these multilateral agreements without waiting for the deadline. This strategy is the one chosen by Cambodia, which has applied MAAS and/or MAFLPAS agreements with Malaysia and Thailand in 2013. In parallel, the bilateral air services agreements with other ASEAN countries, and a few Asian countries, have also been updated in 2013, with removal of constraints on frequencies and capacities. These new air services agreements have already resulted in changes in airline behaviour. This paper analyses changes in the Cambodian market in terms of traffic patterns, airline behaviour, and competition. It provides some hints as to the potential impacts of the ASEAN air transport liberalization on the Cambodian air transport market; highlights the potential benefits and risks, and enlarges the discussion to the other local markets.

Modeling and verification of ATM security policies with SecBPMN

Scipedia content — Tue, 02 Feb 2021 03:50:21 +0100

High Performance Computing (HPC) techniques are essential in complex systems such as Socio-Technical Systems (STSs), where humans and organizations are elements of the same system along with technical infrastructures and hardware/software components. For example, several HPC approaches have been successfully applied to support and facilitate distribution or aggregation of computation power among independent and atomic components (e.g., smart meters to solve and/or simulate complex models). However, HPC techniques have to be studied and developed without underestimating the problem of security that, given the interaction-centric nature of STSs, has to be considered not only from the single component perspective but for the system as a whole. In our previous work, we have proposed SecBPMN, a framework to support the design of secure STSs. It is used to model the interaction design and security policies of a STS and it supports their verification through a querying engine. In this paper, we describe how SecBPMN has been successfully used for the study of security in an Air Traffic Management (ATM) system, and we show how it can result also an efficient support when of HPC techniques when applied in complex and heterogeneous environments.

Auction-based autonomous intersection management

Scipedia content — Tue, 02 Feb 2021 03:48:54 +0100

utonomous vehicles present new opportunities for addressing traffic congestion through flexible traffic control schemes. This paper explores the possibility that auctions could be run at each intersection to determine the order in which drivers perform conflicting movements. While such a scheme would be infeasible for human drivers, autonomous vehicles are capable of quickly and seamlessly bidding on behalf of human passengers. Specifically, this paper investigates applying autonomous vehicle auctions at traditional intersections using stop signs and traffic signals, as well as to autonomous reservation protocols. This paper also addresses the issue of fairness by having a benevolent system agent bid to maintain a reasonable travel time for drivers with low budgets. An implementation of the mechanism in a microscopic simulator is presented, and experiments on city-scale maps are performed.

Intentional Destructive Testing: A Means for Establishing Mechanical Integrity in Plants, Facilities, and Pipelines

Scipedia content — Tue, 02 Feb 2021 03:40:47 +0100

Operators of plants, facilities, and pipelines have at their disposal multiple resources for evaluating the integrity of identified features and anomalies. With advances in inspection technology, industry is being called upon to evaluate an ever-increasing number of features. When a feature is identified as a threat and severe enough to warrant repair or replacement, operators are faced with sometimes significant costs."/jats:p" "jats:p"In this paper the authors provide guidance on the benefits associated with full-scale testing for evaluating mechanical integrity, referred to Intentional Destructive Testing (IDT). Unlike many analysis techniques that require the development and implementation of assumed operating and boundary conditions, well-designed IDT programs are able to replicate in situ conditions to provide operators with a clear understanding regarding the behavior of anomalies and their response to simulated operating conditions. Case studies are included to demonstrate the merits of the IDT approach. In using IDT, operators have improved confidence in predicting the behavior of identified features to ensure that maintenance resources are properly allocated for either continuing operation or repairing anomalies.

The three Cs of intensity: understanding rail-based urban assemblage in Brooklyn

Scipedia content — Tue, 02 Feb 2021 03:40:32 +0100

Transit-oriented urban intensification is proposed to be the most fundamental planning approach for a sustainable city. The key notion of urban intensity remains vague referring to the integration of land-use, transport and density. Limited research at local scale, reduction to urban form and the lack of a clear conception of intensity has led to inconsistencies in the discourse of transit-orientation. The Brooklyn case study is presented as a laboratory for exploring urban intensity of this rail-based assemblage. The selected study area is mid-rise, compact mix of housing, retail, offices, industry and amenities. The analysis is based on assemblage thinking: place is conceived as a synergy of people, dwellings, functions, densities, flows and practices. It is here proposed that the three complementary Cs: concentration, connectedness and co-functioning mediate urban intensity. Concentration resonates with building heights, site coverage, dwelling densities, co-functioning with functional, formal and social mix, and connectivity with access, movement networks. Urban intensity emerges from the interaction, links and adaptations of the three Cs, and is manifested in flows of people, transport, information and goods throughout the city. This paper explores ways in which urban intensity emerges in the Brooklyn assemblage. This comprehensive multi-scalar understanding of urban intensification contributes to sustainable urban practices.

Dynamic Social Network Analysis for Infrastructure Transportation Systems

Scipedia content — Tue, 02 Feb 2021 03:28:05 +0100

It is essential to build, maintain, and use our transportation systems in a manner that meets our current needs while addressing the social and economic needs of future generations. In today’s world, transportation congestion causes serious negative impacts to our societies. To this end, researchers have been utilizing various statistical methods to better study the flow of traffic into the road networks. However, these valuable studies cannot realize their true potential without solid in-depth understanding of the connectivity between the various traffic intersections. This paper bridges the gap between the engineering and social science domains. To this end, the authors propose a dynamic social network analysis framework to study the centrality of the existing road networks. This approach utilizes the field of network analysis where: (1) visualization and modeling techniques allow capturing the relationships, interactions, and attributes of and between network constituents, and (2) mathematical measurements facilitate analyzing quantitative relationships within the network. Connectivity and the importance of each intersection within the network will be understood using this method. The authors conducted social network analysis (SNA) using a two studies in Louisiana. Results indicate intersection SNA modeling aligns with current congestion studies and transportation planning decisions.

Assessing map-based maneuver hypotheses using probabilistic methods and evidence theory

Scipedia content — Tue, 02 Feb 2021 03:27:41 +0100

The prediction of the behavior of other traffic participants and the generation of appropriate motion hypotheses is a key capability of advanced driver assistance systems and autonomous vehicles. Motion prediction is a difficult task since it has to deal with the uncertainty within the environmental perception and the ambiguity of a traffic scene. For this reason the authors propose a two-layer situation analysis concept. This includes an associative and predictive situation model which combines probabilistic object hypotheses with a stochastic model of the road network in a curve coordinate system. Utilizing this description, the authors formulate various hypotheses regarding the evolvement of the situation using an Extended Kalman Filter supported by the Intelligent Driver Model. Furthermore, the authors introduce an evidence theory based situation interpretation to assess the several behavior hypotheses as well as to determine the inherent uncertainty. Especially in ambiguous situations, the ability to determine the imprecision by the difference of belief and plausibility of a certain hypothesis provides suitable information for an appropriate reaction. Both layers of the proposed situation analysis are not relying on training data and so it is not limited to previous known traffic scenarios. Finally, the capability of the concept is demonstrated by evaluating 157 maneuvers, recorded at an urban intersection.

3D MODELS OVER THE CENTURIES: FROM OLD FLOOR PLANS TO 3D REPRESENTATION

Scipedia content — Tue, 02 Feb 2021 03:21:50 +0100

International audience; This paper presents a set of algorithms dedicated to the 3D modeling of historical buildings from a collection of old ar-chitecture plans, including floor plans, elevations and cut-offs. Image processing algorithms help to detect and local-ize main structures of the building from the floor plans (thick and thin walls, openings). The extrusion of the walls allow us to build a first 3D model. We compute height informations and add textures to the model by analyzing the elevation im-ages from the same collection of documents. We applied this pipeline to XVIII th century plans of the Château de Versailles, and show results for two different parts of the Château.

High-efficiency step-down converter for on-board thermoelectric generators on heavy duty vehicles

Scipedia content — Tue, 02 Feb 2021 03:16:18 +0100

Today's combustion engines have low efficiency and a large amount of useful energy converts to heat as waste in different type of vehicles. Improving the dynamics of the car body, injection system, the shape of the internal engine components and manipulating the fuel compositions have had influence on fuel economy, but still less than 50% of energy in the fuel is converted to useful mechanical power. Since the lost energy escapes through the exhaust system as heat, taking advantage of thermoelectricity, part of that energy can be converted to useful electrical energy, improving the overall efficiency. However, the output voltage from a thermoelectric generator is a function of hot and cold side temperature and since, the electrical system of the vehicle operates with constant voltage, the use of a power converter is necessary. In this paper, simulation and experimental results of such a high-efficiency converter(94-96%), designed for thermoelectric generators on heavy duty vehicles is presented and discussed. "p"QC 20150904

A simulation-based algorithm for the integrated location and routing problem in urban logistics

Scipedia content — Tue, 02 Feb 2021 03:01:19 +0100

In most medium and large sized cities around the world, freight transportation operations might have a noticeable impact on urban traffic mobility as well as on city commercial activities. In order to reduce both traffic congestion and pollution levels, several initiatives have been traditionally implemented. One of the most common strategies concerns the allocation of urban distribution warehouses near the city center in order to consolidate freight delivery services. This paper considers the integrated problem of locating distribution centers in urban areas and the corresponding freight distribution (vehicle routing). The combined problem is solved by using a hybrid algorithm which employs Monte Carlo simulation to induce biased randomness into several stages of the optimization procedure. The approach is then validated using real-life data and comparing our results with results from other works already available in the existing literature.