Scipedia: Documents published in 2016

A national power infrastructure for charge-on-the-move

Scipedia content — Tue, 02 Feb 2021 03:31:13 +0100

It has been generally accepted that electrification of the road transport sector could be a critical step for coping with climate change. Charge-on-the-move is considered to be a critical enabling factor in moving towards electric vehicles and roads. The development of individual charging devices for implementing in-motion charging has been rapid but their integration with the road infrastructure at national scale is still in need of more comprehensive consideration. This work focuses on the challenges of the technology at the level of the system and aims to outline the performance requirements of a national power infrastructure suitable for implementing charge-on-the-move. A UK strategic overview suggests that the installation of a nationwide charging infrastructure of this type is economically feasible. From an estimation of electric vehicles' power requirements in conjunction with UK road traffic data the baseline of the anticipated power demand can be established. Finally, a simulation tool was proposed to investigate the application of dynamic charging and the effects of system design variables on important performance parameters of travelling electric vehicles.

Aircraft Performance for Open Air Traffic Simulations

Scipedia content — Tue, 02 Feb 2021 03:30:22 +0100

The BlueSky Open Air Traffic Simulator developed by the Control \\& Simulation section of TU Delft aims at supporting research for analysing Air Traffic Management concepts by providing an open source simulation platform. The goal of this study was to complement BlueSky with aircraft performance models in order to enable performance-related Air Traffic Management studies. The aircraft performance model developed within this work consists of a kinetic Flight Dynamics Model, which stores the required performance characteristics in a database with type-specific aircraft and engine coefficients. Currently, sixteen commercial turbofan and turboprop aircraft from different range and weight categories are represented. To evaluate the quality of the aircraft performance model, its outputs were compared to results from literature as well as from real flights. It was found that the applied methodologies for the determination of aircraft performance accurately model high-speed drag polars as well as fuel consumption for cruising and taxiing aircraft. The fuel consumption model of climbing and descending aircraft, however, leaves room for improvement. Possible strategies for obtaining a more precise estimation of fuel burn over the entire flight are recommended based on the results of this study. With this work, the BlueSky Open Air Traffic Simulator considers individual aircraft performance. This is an important step in the creation of an open simulation platform for Air Traffic Management research.

Deep learning applied to driving environments

Scipedia content — Tue, 02 Feb 2021 03:22:56 +0100

This presentation was aimed to explore the growing opportunities to merge two booming fields: deep learning and autonomous vehicles, from a technical point of view. It addressed some Intelligent Systems Laboratory (Universidad Carlos III de Madrid, Spain) developments in this line of research, such as an obstacle detection framework using convolutional neural networks (CNNs). Furthermore, it presented a large number of challenging driving-related tasks that were expected to become tractable through this new approach, with the focus on the strong requirements posed by the upcoming self-driving systems."/p" "p"This presentation was part of the 6th LSI Ph.D. Meeting, which was held on 14 Jun 2016 at the Escuela Politécnica Superior of the Universidad Carlos III de Madrid. It was published on Zenodo as an exercise within the THOR Bootcamp on Open Data, organized on 16 Nov 2016.

Risk Analysis of falsified Automatic Identification System for the improvement of maritime traffic safety

Scipedia content — Tue, 02 Feb 2021 03:17:12 +0100

International audience; On board vessels, the Automatic Identification System sends and receives localization messages and enables vessels to better understand their surroundings. Initiated by the Safety Of Life At Sea convention, this system is used for navigation security and safety, boarding prevention, fleet control or traffic control. Some of the messages broadcasted contain errors, falsification and undergo spoofing that weaken the capaci-ties of the system to achieve its goals. This paper presents a risk analysis study of the Automatic Identification System that leads to the identification of circa 350 threat scenarios. A typology of anomalies is proposed, alongside with a methodology for anomaly detection. The objectives are the determination of the false mes-sages and the improvement of both the effectiveness of the system as a security system and the maritime situa-tional awareness.

Mileage electrification potential of different electric vehicles in Germany: Paper presented at the European Battery, Hybrid and Fuel Cell Electric Vehicle Congress, 14th - 16th March 2017, Geneva, Switzerland

Scipedia content — Tue, 02 Feb 2021 03:15:04 +0100

Electric vehicles (EV), both as battery electric vehicles (BEV) and plug-in hybrid electric vehicles (PHEV) have noteworthy potential to reduce global and local CO2 emissions. However, the fully exploitable potential depends on the actual vehicle kilometers travelled (VKT) that can be electrified. For BEV, the limited range excludes long-distance trips from electrification. For PHEV, long-distance trips are not excluded but the shorter electric driving range could reduce the miles electrified. The aim of the present paper is to compare the potential to electrify total VKT of BEV and PHEV. We use real-world driving data from several 780 German conventional passenger cars that are simulated as BEV and PHEV of different ranges. Furthermore, the CO2 emission reduction potential of both technologies and the influence of battery sizes are analyzed, by combining electrified kilometers with CO2 emission factors. We find PHEV to electrify more miles, both individual VKT as well as total VKT of the overall car fleet for given electric range. The difference in fleet electrification potential is maximal for about 30 km electric range. Compared to conventional vehicles both PHEV and BEV can significantly reduce well-to-wheel CO2 emissions when using renewable energies for recharging. The maximal reduction potential per vehicle is larger for PHEV and achieved at smaller range than for BEV.

Urban Traffic Jam Simulation and Prediction

Scipedia content — Tue, 02 Feb 2021 02:53:05 +0100

the rapid increase of traffic flow around the world, the development of the city is increasingly becoming saturated. The traffic flow theory that can guide and schedule traffic is needed. Traffic flow model based on cellular automata which is used to describe the freeway traffic flow model has been reaching maturity and applied to the actual traffic simulation system. And the traffic flow model that used to describe the city road network, referred as BML model) still remains in the stage of theoretical research. Many scholars analyze the BML model by analyzing phase-change principle and making theoretical proof. Yet the scholars have not applied the BML model into the actual urban traffic network, and intelligent scheduling and guidance. The basic BML model is improved to predict traffic congestion of the actual city road network. This study focuses on the amelioration of BML model and the numerical simulation based on this model. The main idea of this paper is: (1) the real urban traffic road network mapped to the D-BML model in accordance with a certain strategy. And the proportion of traffic volume density should be mapped to the D-BML model in accordance with of the road network in a time period. (2)D-BML model evolves in accordance with rule 184 of the cellular automaton evolution. The jam coordinate values of model grid points can be got when the model eventually enter the blocked state. (3)The severe congestion at the intersection also can be got in the next period of time. The experimental results show that the proposed D-BML model can accurately predict the blocked intersection in the road network. The first analysis of the D-BML model density of traffic is on the uniform distribution and Poisson distributions. The blockage values on the model grid are analyzed. The experiments show that as long as the initialization traffic flow density distribution determined, the clogging grid points will not change. Then engineering experiments are made. The simulation experiments of this article are about England's Birmingham City traffic network. The final experimental results are very consistent with the actual traffic clogged intersections, which strongly proved correctness and effectiveness of M-BML model.

Assessing the sustainability of urban food systems for collective uses: case study of a French city

Scipedia content — Tue, 02 Feb 2021 02:51:04 +0100

International audience; The task of feeding cities is a challenge that nowadays all governments face, which involves the coordination of multiple producers, distributors, logistics operators and traders of perishable foods. With the increasing population in cities, more food and better freight transport systems are required. This takes a particular importance in cities and urban zones, since the growing population needs to be fed, but freight transport is often seen as creating nuisances such as congestion or pollution, among others. In this context, several cities started to think on how improve the city’s food supply system by combining proximity producers’ supply with advanced city logistics systems in order to decrease transport nuisances and improve the quality and sustainability of the food system.One of the possible actions is that of deploying proximity food hubs with a consequent urban food distribution system to supply the different urban zones of a city. However, this type of system is starting to be conceived and there is need of assessing the impacts of such alternative before thinking on its deployment possibilities. For this reason, this paper aims to propose a framework to assess different food delivery alternatives in the urban context focusing on a Food hub deployment and its impacts on urban development as a solution of urban consolidation center (UCC).The objective of this study is to enable municipalities to assess the consequences of food logistics flows centralization on an UCC-based food hub. Regarding the context of the research, the study focuses on a Food hub deployment to share the supplies for administrative restaurants of a city, following the sustainable food strategy of a French municipality. This municipality decided to show the example in terms of sustainable food supply and aims to increase the part of organic and local food for the administrative restaurants under its coordination. To do this, a specific food system needs to be conceived and assessed. To assess the suitability of such systems, it will be necessary to model both the demand and the logistics supply, to define the main indicators of sustainability and their estimation methods, then to construct the scenarios to assess and finally make the corresponding analyses.

Offloading personal security applications to the Network Edge: A mobile user case scenario

Scipedia content — Tue, 02 Feb 2021 02:49:41 +0100

This paper discusses some challenges that user mobility imposes over the user-centric protection model against security threats. This model is based on the idea of offloading the security applications from the end user device, and placing them in a trusted network node at the network's edge. Our research perspective is particularly centered around three interrelated mobility challenges, i) the allocation of the security applications “close” to the user, i.e., on network nodes with enhanced processing capabilities, ii) seamless mobility with negligible disruption of ongoing network connections, and iii) dynamic orchestration and management with support of security applications migration. Based on our arguments, we expose the main requirements and trade-offs to be considered in the attempt to support mobility in such environment. We propose a flexible solution that leverages Software Defined Networking, Network Function Virtualization and Computing at the Network Edge to offer a seamless on-path security protection to mobile users. Our preliminary experiments' results considering a WiFi mobile user show that seamless security migration and mobility are feasible in a simple real scenario. Vertical mobility and more complex use cases scenarios are envisioned for future research.

Peer Reviewed

Document type: Conference object

Evaluating Application-Layer Traffic Optimization Cost Metrics for P2P Multimedia Streaming

Scipedia content — Tue, 02 Feb 2021 02:46:47 +0100

To help users of P2P communication systems perform better-than-random selection of communication peers, Internet Engineering Task Force standardized the"br/"Application Layer Traffic Optimization (ALTO) protocol. The ALTO provided data-routing cost metric, can be used to rank peers in P2P communication systems. However, the method to derive the data-routing cost metric is undefined by the standard. This paper proposes and evaluates three methods to derive the data-routing cost metric for use in ALTO servers.

Design of Ultra-Low-Power Smart Wearable Systems

Scipedia content — Tue, 02 Feb 2021 02:45:43 +0100

Latest progress in microelectronics have enabled a new generation of low cost, low power, miniaturized, yet, smart sensor nodes. This new generation of wearable sensor nodes promise to deploy automated complex bio-signals analysis. In this paper, we present INYU, a wearable sensor device for physical and emotional health monitoring. The device obtains key vital signs of the user, namely Electrocardiogram (ECG), respiration and skin conductance continuously. Using this information, INYU can deliver a novel real-time algorithm for on-line heart-beat classification and correction that relies on a probabilistic model to determine whether a heartbeat is likely to happen under certain timing conditions. Thus, using this algorithm INYU can quickly decide if a beat is occurring at an expected time or if there is a problem in the series (e.g., a skipped, an extra or a misplaced beat). This new algorithm has been integrated in the processing pipeline of automated Heart-Rate Variability (HRV) analysis, both for time-domain (RMSSD, SDNN) and frequency-domain (LF/HF) algorithms.

Societal Drivers For The Future Transport System In Europe: The Mobility4Eu Project

Scipedia content — Tue, 02 Feb 2021 02:40:01 +0100

Global socio-economic and environmental megatrends ask for a paradigm shift in mobility and transport in which multimodal solutions and electrification are key. An action plan for the implementation of innovative transport and mobility in Europe is needed. The MOBILITY4EU project develops such a plan considering all modes of transport and a multitude of societal drivers. It uses a Multi-Actor-Multi-Criteria Analysis (MAMCA) methodology for consulting a broad societal stakeholder community. This paper will present objectives and methodology of the project and results on the interaction between societal trends and formulation of (future) societal requirements on transport.

Concept development for vehicle design education projects carried out in collaboration with industry

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

This paper describes the concept development process of three vehicle design team projects carried out in successive years in our fourth year undergraduate studio course, in collaboration with industry. The problem areas for all three projects were unfamiliar to student teams, and our collaboration required close involvement of the firms, for their technical expertise and design feedback. Our framework and strategies for this process involved: user research conducted in the field; group discussions for analyzing the operations carried out by the users and mapping their relation to the functions of the related hardware; scenario building for describing the context within an activity based time-related process and searching for solutions at the same time; the generation of numerous ideas through the matching of alternative scenarios with the project dimensions; convergence of these ideas into alternative design proposals; and decision-making on the final project concepts. User research extended throughout the concept development process, supported with an intense 3D exploration and with class assignments that encouraged goal-oriented teamwork. Although we followed a similar design process in all three projects, the strategies used in the various stages were modified depending on the requirements of each project, and regarding the differences in the vehicle types involved, the users and the tasks. (C) 2016 The Authors. Published by Elsevier B.V.

An Improved Actuated Signal Control of Intersection Based on VISVAP

Scipedia content — Tue, 02 Feb 2021 02:24:22 +0100

Traffic congestion has become an inevitable problem in modern society, and the signal control of intersection plays an important role to ensure the effective operation of urban transport. The paper proposes an improved actuated signal control model to improve the running efficiency of intersection. In order to verify the effectiveness of the improved algorithm,the paper uses VISSIM to simulate the operating condition of different durations under timing control, actuated signal control and improved actuated signal control based on actual traffic flow, signal timing and other data of intersection. The simulation result shows that travel time and delay time are both reduced under the control of actuated signal in different time periods. And the improved actuated signal control is more effective than other signal controls.

DORA – Integration of air transport in overall urban and regional mobility information

Scipedia content — Tue, 02 Feb 2021 02:21:44 +0100

DORA stands for “Door to Door Information for Passengers and Airports” and targets on seamless integration of air mobility in the overall urban and regional transport systems. Integrating real time data and incident information of both transport modes in one information system the DORA closes the information gap between air transport and landside transportation. The overall goal of the DORA project activities is to optimise and reduce the total travel time, taking into account origins and final destinations of the travels and make sure that even in case of land traffic disruptions and critical situations at the airports the passengers arrive at the airport in time to complete all necessary clearance procedures before entering the plane. The DORA system is based on two innovations: A cross-modal incident management and information system to ensure the accessibility of airports at all times. This system is based on the cooperation of all transport operators to manage disturbances in the airport bound public transport system and road traffic based on pre-defined action plans and information strategies. The second pillar is a multimodal mobile information service for air passengers. This DORA app helps passengers to plan their trip to the airport, to find the shortest way in the terminals and provides passengers with the trip recommendation on how to travel from the destination airport to their final destination. The third pillar is the exploring of technologies for time efficient procedures in the terminal. Special emphasis is put on detection of waiting times at check-ins or security checks and indoor routing and navigation technologies to improve the service quality in the terminal. DORA will be a seamless solution through considering scheduled and real time services of all flight connection and urban transport modes and terminal proceedings (luggage belt, security gate, departure gates), The system will integrate services for a door-to-door journey planning, booking and ticketing for landside transport with strategic compliancy (with static and dynamic control strategies) of operator and municipalities, as well as online trip monitoring.

An Improved Simulated Annealing Technique for Enhanced Mobility in Smart Cities

Scipedia content — Tue, 02 Feb 2021 02:21:12 +0100

Vehicular traffic congestion is a significant problem that arises in many cities. This is due to the increasing number of vehicles that are driving on city roads of limited capacity. The vehicular congestion significantly impacts travel distance, travel time, fuel consumption and air pollution. Avoidance of traffic congestion and providing drivers with optimal paths are not trivial tasks. The key contribution of this work consists of the developed approach for dynamic calculation of optimal traffic routes. Two attributes (the average travel speed of the traffic and the roads’ length) are utilized by the proposed method to find the optimal paths. The average travel speed values can be obtained from the sensors deployed in smart cities and communicated to vehicles via the Internet of Vehicles and roadside communication units. The performance of the proposed algorithm is compared to three other algorithms: the simulated annealing weighted sum, the simulated annealing technique for order preference by similarity to the ideal solution and the Dijkstra algorithm. The weighted sum and technique for order preference by similarity to the ideal solution methods are used to formulate different attributes in the simulated annealing cost function. According to the Sheffield scenario, simulation results show that the improved simulated annealing technique for order preference by similarity to the ideal solution method improves the traffic performance in the presence of congestion by an overall average of 19.22% in terms of travel time, fuel consumption and CO2 emissions as compared to other algorithms; also, similar performance patterns were achieved for the Birmingham test scenario.

Document type: Article

Future of Electric Vehicle Charging

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

Charging infrastructure for electric vehicles (EV) will be the key factor for ensuring a smooth transition to e-mobility. This paper focuses on five technologies that will play a fundamental role in this regard: smart charging, vehicle-to-grid (V2G), charging of EVs from photovoltaic panels (PV), contactless charging and on-road charging of EVs. Smart charging of EVs is expected to enable larger penetration of EVs and renewable energy, lower the charging cost and offer better utilization of the grid infrastructure. Bidirectional EV chargers will pave the way for V2G technology where the EV can be used for energy arbitrage and demand-side management. Solar charging of EV will result in sustainable transportation and use of the EV battery as PV storage. On the other hand, stationary contactless charging and on-road inductive charging of EV will remove the necessity for any cables, eliminate range anxiety issues and pave the way for automated driving. The electromagnetic and power converter design for contactless power transfer systems for future highways is reviewed in this paper.

Post-Production Heavy Oil Operations: A Case For Partial Upgrading

Scipedia content — Tue, 02 Feb 2021 02:18:00 +0100

This paper investigates the economic viability of post-production partial upgrading, specifically visbreaking, of heavy oil. We evaluate the potential technical and economic advantages and disadvantages of using visbreaking as a tool for reducing diluent use. Additionally, we identify the cost and energy drivers affecting the economic performance of this partial upgrading operation through a probabilistic Net Present Value (NPV) analysis. We have created a screening tool that can be used for a preliminary evaluation of visbreaking for transportation of heavy-oil solvent systems. Partial upgrading at the wellsite can potentially reduce operational costs to producers and transportation companies. A comparative economic study offered by this test can be used to make decisions on whether to proceed to a more detailed investigation of the process. Importantly, we have created a first-pass standardization tool for the screening of heavy oils for partial upgrading. Visbreaking can prove to be an economically favorable addition or, perhaps, even an alternative to blending heavy oil prior to pipeline transportation. In fact, operational costs of visbreaking are offset by the reduced cost of diluent and capital expenditures that can be mitigated within a reasonable time frame. Finally, we conclude that the altered fluid properties of a visbroken product require less energy per barrel for transportation, which translates to a more attractive economic scenario for transportation for the two baseline cases presented.

Learning Energy Storage in Hybrid/Electric Vehicles: Erasmus Mundus Master Course in Sustainable Transportation & Electrical Power Systems

Scipedia content — Tue, 02 Feb 2021 02:15:17 +0100

The "Erasmus Mundus Master Course in Sustainable Transportation a Electrical Power Systems" is supported by three universities, located in Spain, Italy and United Kingdom, and a Polytechnic Institute in Portugal. One of the main goals is the training of qualified staff in areas related to electrical energy management, emphasizing in power systems for electric propulsion vehicles and renewable energies. Among others, the subject "Energy Storage and Recovery in Power Systems and Hybrid/Electric Vehicles" is considered a keystone in the Master. During third semester, the students who follow the technical track, have to develop small projects and tasks related to electric vehicles, battery management, power stages for battery charger and so on. This paper show the goals and the results obtained in these topics. All of these topics are partially collected in one subject, with a high practical content. The students have to learn not only the theoretical topics, but they have to elaborate a project, in a work team and use modern laboratory equipment as well. It should be noted that the students have to work and collaborate in a multicultural environment, with students and professors. This paper describes the subject methodology, and the results obtained.

Parking equilibrium along the street

Scipedia content — Tue, 02 Feb 2021 02:12:19 +0100

International audience; Purpose.The paper studies the progressive occupancy of parking capacity along the street by candidate users, under the user equilibrium paradigm. The situation depicted typically applies to a parking peak period.Methods.In our model, the parking supply is made up of capacitated lots situated along a spatial axis, while the demand is disaggregated continuously in both destination place and preferred time of arrival. Each user selects a parking lot and time from among options on the basis of their trade-offs between walking, driving, parking price and schedule delay. Efficient algorithms are developed and an application instance is dealt with in detail.Results.The dynamical equilibrium pattern exhibits parking lots “efficiency regions” in the plane of destination places and preferred arrival times. These efficiency regions are dynamic market areas with strong yet simple structural characteristics, making it easy to assign each parking user to his preferred option and to derive the lot saturation times. The latter are identified as the key state variables for the parking system, since they induce the lot efficiency regions. The equilibrium state is characterized as the solution to a fixed-point problem with respect to the saturation times.Conclusion.Our model improves upon previous parking models in economic theory, by adopting a higher resolution in space and time on both supply and demand side. The higher resolution is enabled by focusing on the street level, thus restricting the outreach of the model. Further research may be directed to extend the model to a network of streets, on the side of traffic assignment, and to study parking management policies, on the side of parking economics.

Document type: Article

Social sustainability and smart mobility : exploring the relationship

Scipedia content — Tue, 02 Feb 2021 02:09:33 +0100

In this article the relationship between two broad concepts will be explored. The first concept is social sustainability, a concept still in discussion. The second concept is smart mobility, a new concept, related to IT- related mobility options and solutions. How social sustainable is smart mobility ? This article offers a clarification of both concepts and of the relationships between the concepts. The conclusion is that whether smart mobility will be social sustainable depends on the route smart mobility will take; only related to cars, and to higher segments of the fleet, or broader in scope and more related to mobility services. Keywords social sustainability; smart mobility; mobility services; equity; accessibility; social cohesion

Reduction and calibration pipelines for e-MERLIN and COBRaS

Scipedia content — Tue, 02 Feb 2021 01:54:03 +0100

Detection of urban traffic patterns from Floating Car Data (FCD)

Scipedia content — Tue, 02 Feb 2021 01:42:49 +0100

Real time data collection in traffic engineering is crucial for better traffic corridor control and management. In the literature, many data collection methods have been used such as; magnetic loops, road tube counters, piezo sensors, radars, Bluetooth etc. to estimate the link occupancy, average speed or density of a corridor. More recently, Floating Car Data (FCD) has become another important traffic data source and has an increasing usage due to its lower cost and higher coverage despite its reliability problems. FCD obtained from GPS equipped vehicles moving in the traffic can provide speed or travel speed data for many segments for even 1-min intervals in real-time. Though not totally diverse providing more than one of the traffic flow parameters, measuring the effectiveness of this extensive data source in detecting some critical urban traffic states is the ultimate goal of this study. As a case study, 1-min interval FCD for an urban arterial in Ankara has been collected during the morning peak hour for 2 months. Average speed values were transformed into a qualitative 4-scale state parameter based on the Level of Service (LOS) definitions for urban roads. Pattern searches over consecutive segment states using different search length (i.e. 2 segments, 3 segments, etc.) showed that FCD is capable to detect recurrent congestion or bottleneck locations, and even have an idea about the length of queue formed before the bottlenecks. (C) 2016 The Authors. Published by Elsevier

Investigating the Empirical Existence of Static User Equilibrium

Scipedia content — Tue, 02 Feb 2021 01:40:19 +0100

The Static User Equilibrium is a powerful framework for the theoretical study of traffic. Despite the restricting assumption of stationary flows that intuitively limit its application to real traffic systems, many operational models implementing it are still used without an empirical validation of the existence of the equilibrium. We investigate its existence on a traffic dataset of three months for the region of Paris, FR. The implementation of an application for interactive spatio-temporal data exploration allows to hypothesize a high spatial and temporal heterogeneity, and to guide further quantitative work. The assumption of locally stationary flows is invalidated in a first approximation by empirical results, as shown by a strong spatial and temporal variability in shortest paths and in network topological measures such as betweenness centrality. Furthermore, the behavior of spatial autocorrelation index of congestion patterns at different spatial ranges suggest a chaotic evolution at the local scale, especially during peak hours. We finally discuss the implications of these empirical findings and describe further possible developments based on the estimation of Lyapunov dynamical stability of traffic flows.

Comment: 9 pages, 5 figures. Forthcoming in Transportation Research Procedia, EWGT2016, 5-7 September 2016, Istanbul

Research on Solutions for Urban Traffic Congestion

Scipedia content — Tue, 02 Feb 2021 01:36:10 +0100

The Effect of Spiral Cold-Bending Manufacturing Process on Pipeline Mechanical Behavior

Scipedia content — Tue, 02 Feb 2021 01:35:53 +0100

Large-diameter spiral-welded pipes are employed in demanding hydrocarbon pipeline applications, which require an efficient strain-based design framework. In the course of a large European project, numerical simulations on spiral-welded pipes are conducted to examine their bending deformation capacity in the presence of internal pressure referring to geohazard actions, as well as their capacity under external pressure for offshore applications in moderate deep water. Numerical models that simulate the manufacturing process (decoiling and spiral cold bending) are employed. Subsequently, the residual stresses due to cold bending are used to examine the capacity of pipe under external pressure and internally-pressurized bending. A parametric analysis is conducted to examine the effect of spiral cold forming process on the structural behavior of spiral welded pipes and the effect of internal pressure on bending capacity. The results from the present study support the argument that spiral-welded pipes can be used in demanding onshore and offshore pipeline applications.

Study on Detecting Location for Bus Rapid Transit with Signal Priority

Scipedia content — Tue, 02 Feb 2021 01:24:54 +0100

Network Fundamental Diagram (NFD) and traffic signal control: first empirical evidences from the city of Santander

Scipedia content — Tue, 02 Feb 2021 01:21:29 +0100

According to recent literature, the aggregate traffic conditions of an urban road network may be measured by an asymmetric inverse-U shaped diagram, called Network or Macroscopic Fundamental Diagram (NFD or MFD). The research on NFD was finalizes for applications connected to congestion control by means of gating, pricing schemes, multi-modal network analysis, freight vehicle routing. The control of urban road networks by means of NFD is a promising research area, where new methods and models are proposed to reduce traffic congestion and delay. The general objective of the research is to investigate if and in which measure the NFD profile (estimated by means of observed traffic data) changes according to the control strategy adopted for junction signals in an urban area. The first empirical evidences presented in this paper are related to a portion of Santander urban area, where a specific zone has been identified according to traffic characteristics and land uses. Data from traffic loops are collected and correlated with the signal control plans during a working day at link (flow-density diagrams) and network levels (NFD). Some preliminary considerations are derived from the empirical results. The cycle length with a fixed regulation plan does not influence the main traffic variables (flow, density) at link and network level, but these results cannot be generalized.

Part-time amenity migrants: Revealing the importance of second homes for senior residents in a transit-oriented development

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

Transit-oriented development (TOD) has been proposed as a model for sustainable urban and regional development beyond the troubled heritage of modernistic planning. Key to TOD is mixed use and reduced dependence on private cars. However, functionalistic land-use divides persist in the principles of TOD, such as the division between leisure and work and between permanent residences and second homes. These divides relate to, and are emphasised by, a strong focus on urban qualities within the TOD discourse, while discussions on landscape amenities are set aside. Following recent research on compensation theory and amenity migration, this study argues that densification of TODs could increase residents’ dependency on second homes in the countryside. The study provides insights gained from semi-structured interviews with senior residents in newly-built apartments and houses in a TOD location in Sweden. The interviews revealed how the importance of multiple dwellings is enhanced by the densification project and how car dependency is built into the model. The term ‘part-time amenity migrant’ has been coined to describe this phenomenon and increase awareness of landscape amenities in TOD locations.

Comparative assessment of safety indicators for vehicle trajectories on the highway

Scipedia content — Tue, 02 Feb 2021 01:14:38 +0100

Safety measurement and analysis have been a challenging and well-researched topic in transportation. Conventionally, surrogate safety measures have been used as safety indicators in simulation models for safety assessment, in control formulations for driver assistance systems, and in data analysis of naturalistic driving studies. However, surrogate indicators only give partial insights into traffic safety i.e., they only indicate a predetermined set of possible pre-crash situations for an interacting vehicle pair. Recently, a safety indicator called the driving safety field based on field theory has been proposed for two-dimensional vehicle interactions. However, the objectivity of its functional form and validity are yet to be tested. This paper provides a qualitative and quantitative comparison of different safety indicators as a risk measure to demarcate their mathematical properties and evaluate their usefulness in quantifying trajectory risk. We compare five relevant safety indicators: inverse time to collision, post-encroachment time, potential indicator of collision with urgent decceleration, warning index and safety field strength. Their formulations are mathematically analyzed to yield qualitative insights and their values over simulated vehicle trajectories are evaluated to yield quantitative insights. Our results acknowledge the limitations and demarcate the functional utilities of the selected safety indicators.

Development Mode and Strategy of High-density City Underground Space

Scipedia content — Tue, 02 Feb 2021 01:06:20 +0100

The large-scale development of urban underground space is the inevitable trend of high-density city economic development height. With increasing height and density of buildings, urban ground space is very crowded, such as, traffic congestion, lack of greening, serious environment pollution and lack of humanized living space. Therefore, in order to address this tension state of ground, we must strive to develop underground space, and form a three-dimensional and highly-efficient urban space system.

Dynamic cluster-based over-demand prediction in bike sharing systems

Scipedia content — Tue, 02 Feb 2021 00:53:45 +0100

International audience; Bike sharing is booming globally as a green transportation mode, but the occurrence of over-demand stations that have no bikes or docks available greatly affects user experiences. Directly predicting individual over-demand stations to carry out preventive measures is difficult, since the bike usage pattern of a station is highly dynamic and context dependent. In addition, the fact that bike usage pattern is affected not only by common contextual factors (e.g., time and weather) but also by opportunistic contextual factors (e.g., social and traffic events) poses a great challenge. To address these issues, we propose a dynamic cluster-based framework for over-demand prediction. Depending on the context, we construct a weighted correlation network to model the relationship among bike stations, and dynamically group neighboring stations with similar bike usage patterns into clusters. We then adopt Monte Carlo simulation to predict the over-demand probability of each cluster. Evaluation results using real-world data from New York City and Washington, D.C. show that our framework accurately predicts over-demand clusters and outperforms the baseline methods significantly

Short-Term Crude Oil Scheduling Modeling and Algorithm with High Fusion Point Oil and Two Pipelines Transportation Based on Priority-Slot

Scipedia content — Tue, 02 Feb 2021 00:52:44 +0100

Some oil refineries arrange low fusion point crude oil storage tanks and high fusion point ones at two different locations. Different fusion point crude oil needs different pipeline to transfer. So, to transport diverse fusion point oil needs two pipelines. Because of the constraints resulted from transferring high fusion point oil, to schedule such an organization is hard. This paper proposes a new MINLP formulation with transferring high-fusion-point oil and two pipelines transfer that is based on single-operation sequencing (SOS). This formulation aims at minimizing the sum of high-fusion-point oil transfer cost. Simple two-stage MILP-NLP heuristic method cannot be applied to solve the model, so we give an iterative algorithm directly using MINLP solver DICOPT to solve it.

Reusable, extensible, and modifiable R scripts and Kepler workflows for comprehensive single set ChIP-seq analysis

Scipedia content — Tue, 02 Feb 2021 00:45:28 +0100

There has been an enormous expansion of use of chromatin immunoprecipitation followed by sequencing (ChIP-seq) technologies. Analysis of large-scale ChIP-seq datasets involves a complex series of steps and production of several specialized graphical outputs. A number of systems have emphasized custom development of ChIP-seq pipelines. These systems are primarily based on custom programming of a single, complex pipeline or supply libraries of modules and do not produce the full range of outputs commonly produced for ChIP-seq datasets. It is desirable to have more comprehensive pipelines, in particular ones addressing common metadata tasks, such as pathway analysis, and pipelines producing standard complex graphical outputs. It is advantageous if these are highly modular systems, available as both turnkey pipelines and individual modules, that are easily comprehensible, modifiable and extensible to allow rapid alteration in response to new analysis developments in this growing area. Furthermore, it is advantageous if these pipelines allow data provenance tracking. Results We present a set of 20 ChIP-seq analysis software modules implemented in the Kepler workflow system; most (18/20) were also implemented as standalone, fully functional R scripts. The set consists of four full turnkey pipelines and 16 component modules. The turnkey pipelines in Kepler allow data provenance tracking. Implementation emphasized use of common R packages and widely-used external tools (e.g., MACS for peak finding), along with custom programming. This software presents comprehensive solutions and easily repurposed code blocks for ChIP-seq analysis and pipeline creation. Tasks include mapping raw reads, peakfinding via MACS, summary statistics, peak location statistics, summary plots centered on the transcription start site (TSS), gene ontology, pathway analysis, and de novo motif finding, among others. Conclusions These pipelines range from those performing a single task to those performing full analyses of ChIP-seq data. The pipelines are supplied as both Kepler workflows, which allow data provenance tracking, and, in the majority of cases, as standalone R scripts. These pipelines are designed for ease of modification and repurposing.

Augmented and Virtual Reality in the Airport Control Tower

Scipedia content — Tue, 02 Feb 2021 00:42:03 +0100

a matter of fact, airports are considered as the bottleneck to increasing the capacity of the overall Air Traffic Management (ATM) system. While augmenting throughput in high performing airport operations, attention has rightly been placed on doing it in a safe manner. Many of the advances in airport operational safety come in the form of visualization tools for tower controllers. The increasing interest in Synthetic Vision (SV) and Augmented Reality (AR) technologies has led various analysts to positively esteem the adoption of new tools enabling both pilots and controllers to seamlessly operate under Visual Meteorological Conditions and Instrument Meteorological Conditions. This paper presents the motivations, the objectives, the proposed methodology and the expected impacts of the RETINA (Resilient Synthetic Vision for Advanced Control Tower Air Navigation Service Provision) project that has recently been granted by the SESAR (Single European Sky Air Traffic Management Research) Joint Undertaking. The two-years exploratory research project will investigate the potential and applicability of SV tools and Virtual/Augmented Reality (V/AR) display techniques for the Air Traffic Control (ATC) service provision by the airport control tower.

Electric tracing system temperature control of submarine heavy oil pipeline based on genetic algorithm

Scipedia content — Tue, 02 Feb 2021 00:36:15 +0100

Framing Social Inclusion as a Benchmark for Cycling-Inclusive Transport Policy in Kisumu, Kenya

Scipedia content — Tue, 02 Feb 2021 00:32:52 +0100

Cycling in many cities of the Global South faces unending exclusion from street spaces despite the on-going transport policy reforms. This exclusion worsens the marginalisation of the poor majority who use this mode. In this paper, we formulate social inclusion as a policy tool for reconciling transport policy to the cycling needs of Kisumu, Kenya. We draw from social quality theory and Lefebvre’s right to the city concept to assemble the ideals of social inclusion. These ideals form the benchmark for a qualitative content analysis of the policy pronouncements contained in the Kenya Vision 2030 and the Integrated National Transport Policy to ascertain the opportunities presented by these policies for cycling inclusion. Findings from interviews held with transport professionals in government and private practice support this content analysis. Results show that while the Kenya Vision 2030 focuses on economic growth, the Government has prioritised the implementation of its projects, thus diminishing the fragile opportunity for cycling inclusion presented by the transport policy. To consolidate this opportunity, we propose different policy recommendations to improve the terms for cyclists to claim and produce street spaces.

Impact of mood changes on application selection

Scipedia content — Tue, 02 Feb 2021 00:21:36 +0100

Users of quantified self applications habitually log and track personal information, such as mood. Attempts to automate the procedure of logging mood have been made, but applications themselves rarely provide insights into the user’s mental well-being. In this paper we explore data from two small scale studies related to mobile device usage and mood tracking. We analyse associations between user’s mood throughout the day and the use of smartphone applications from different categories. Our analysis provides insights into the user’s behaviour based on their device usage. These insights mean that QS applications can independently use simple analysis tools to provide similar insights for the user.

Head up only — A design concept to enable multiple remote tower operations

Scipedia content — Tue, 02 Feb 2021 00:11:49 +0100

Multiple remote tower control aims at enabling one air traffic controller (ATCO) to control simultaneous traffic at two airports at the same time. This concept has the advantage that workforce of the ATCOs can be utilized in an optimized way. Nevertheless, it raises the questions how the workplace should be designed in order to allow the ATCO to handle as much traffic as possible in a safe and efficient manner. One important parameter is the visual attention of the ATCO. Monitoring is the main task of tower ATCOs and is the mechanism by which ATCOs detect deviations between the preplanned and the real traffic situation. As a rule of thumb, air traffic controllers are trained to “look outside” as often as possible, also called working “head-up”. Especially, it is a normative behavior that the controller should monitor an aircraft during the take-off and landing phase in order to detect any hazardous events as early as possible, e.g. a burning engine. In contrast to this rule, the so-called “head-down” times of air traffic controllers increased already over the past years as new information sources were presented to the ATCOs by adding displays to their working positons. So it is of interest; whether ATCOs are able conduct their monitoring task in a multiple remote tower environment where the number of sources with visual information is further increased. Specifically, the ATCOs should be able to monitor take-off and landings as good as compared to working on a single airport.

Generic Management of Availability in Fail-Operational Automotive Systems

Scipedia content — Tue, 02 Feb 2021 00:08:49 +0100

The availability of functionality is a crucial aspect of mission- and safety-critical systems. This is for instance demonstrated by the pursuit to automate road transportation. Here, the driver is not obligated to be part of the control loop, thereby requiring the underlying system to remain operational even after a critical component failure. Advances in the field of mixed-criticality research have allowed to address this topic of fail-operational system behaviour more efficiently. For instance, general purpose computing platforms may relinquish the need for dedicated backup units, as their purpose can be redefined at runtime. Based on this, a deterministic and resource-efficient reconfiguration mechanism is developed, in order to address safety concerns with respect to availability in a generic manner. To find a configuration for this mechanism that can ensure all availability-related safety properties, a design-time method to automatically generate schedules for different modes of operations from declaratively defined requirements is established. To cope with the inherent computational complexity, heuristics are developed to effectively narrow the problem space. Subsequently, this method’s applicability and scalability are respectively evaluated qualitatively within an automotive case study and quantitatively by means of a tool performance analysis.

A New Concept of Functional Energetic Modelling and Simulation

Scipedia content — Tue, 02 Feb 2021 00:05:49 +0100

International audience; In this study a new concept of functional modelling and simulation is introduced. First, the necessity and the expected outcomes of the new concept are explained. Secondly, the methodology of functional modelling based on a modular concept and the basic elements are presented, with details of OFS (Organico Functional Set). Then, the implementation of the new modelling concept using Sherpa Engineering's PhiSim environment is described in order to perform simulations. Finally, the proposed modelling method is applied to two different applications: a generic parallel hybrid electric vehicle (HEV) and a waste water treatment unit of a building. Simulation results of parallel HEV application are also presented.

Exposure-based Road Traffic Fatality Rates by Mode of Travel in France

Scipedia content — Tue, 02 Feb 2021 00:00:11 +0100

Travel practices are changing: bicycle and motorized two-wheeler (MTW) use are rising in some of France's large cities. These are cheaper modes of transport and therefore attractive at a time of economic crisis, but they also allow their users to avoid traffic congestion. At the same time, active transport modes such as walking and cycling are encouraged because they are beneficial to health and reduce pollution. It is therefore important to find out more about the road crash risks of the different modes of transport. To do this, we need to take account of the number of individuals who use each, and, even better, their travel levels. We estimated the exposure-based fatality rates for road traffic crashes in France, on the basis of the ratio between the number of fatalities and exposure to road accident risk. Fatality data were obtained from the French national police database of road traffic casualties in the period 2007-2008. Exposure data was estimated from the latest national household travel survey (ENTD) which was conducted from April 2007 to April 2008. Three quantities of travel were computed for each mode of transport: (1) the number of trips, 2) the distance travelled and (3) the time spent travelling. Annual fatality rates were assessed by road user type, age and sex. The overall annual fatality rates were 6.3 per 100 million trips, 5.8 per billion kilometers travelled and 0.20 per million hours spent travelling. The fatality rates differed according to road user type, age and sex. The risk of being killed was 20 to 32 times higher for motorized two-wheeler users than for car occupants. For cyclists, the risk of being killed, both on the basis of time spent travelling and the number of trips was about 1.5 times higher than for car occupants. Risk for pedestrians compared to car occupants was similar according to time spent travelling, lower according to the number of trips and higher according to the distance travelled. People from the 17-20 and 21-29 age groups and those aged 70 and over had the highest rates. Males had higher rates than females, by a factor of between 2 and 3. When exposure is taken into account, the risks for motorized two-wheeler users are extremely high compared to other types of road user. This disparity can be explained by the combination of speed and a lack of protection (except for helmets). The differential is so great that prevention measures could probably not eliminate it. The question that arises is as follows: with regard to public health, should not the use of MTW, or at least of motorcycles, be deterred? The difference between the fatality risk of cyclists and of car occupants is much smaller (1.5 times higher); besides, there is much room for improvements in cyclist safety, for instance by increasing the use of helmets and conspicuity equipment. Traffic calming could also benefit cyclists, pedestrians and perhaps moped users. Language: en

Document type: Conference object

Uplift Resistance of Buried Pipelines in Dry and Unsaturated Sands: Comparison of Analytical and FE Model Results with Large-Scale Test Data

Scipedia content — Mon, 01 Feb 2021 23:49:53 +0100

Pipelines are commonly buried underground to provide environmental stability, temperature insulation and mechanical protection. These pipelines are frequently subjected to earthquake induced upward displacements, which can cause significant social-economic loss to consumers and utility management. Further, high thermal and pressure of the conveying medium can induce differential stresses on the axial restrained pipe to result in upward buckling of the pipeline that can disturb the serviceability conditions. The uplift resistance from soil cover protects the pipe against such unwanted movements, representing it as a vital design parameter, in that pipeline integrity under operating conditions relies on its value. The paper presents full-scale uplift results and finite-element parametric studies conducted to investigate the effects of dimensionless cover heights (soil cover height to diameter ratio), soil relative density and moisture content on the peak uplift resistance of pipes. The results showed that the available analytical models could predict realistic peak uplift resistance for pipes buried at shallower depths, however, they can substantially under-predict the pipe loads/uplift resistance especially when buried at deeper embedded depths and non-dry soil conditions. The results of the current study are useful for pipe designs against earthquakes and/or severe operating conditions of induced uplift displacements in sandy soils.

Scalable Methods for Monitoring Limited Access Roadways using Crowd-Sourced Probe Data

Scipedia content — Mon, 01 Feb 2021 23:42:29 +0100

Commercial crowd-sourced probe vehicle data has been gaining traction in recent years as a ubiquitous and scalable resource for identifying traffic congestion on limited access roadways. It is routinely used in real-time by navigation software that displays color coded maps. However, outside of public agency traffic management centers, there are no factual “big picture” reports on traffic conditions. The media tries to fill this gap, but they either provide descriptions of construction locations, or highly subjective opinions. This paper proposes and illustrates a “big picture” characterization of regional and national traffic conditions using archived and real-time data. Average speeds of vehicles on segments of roadway can be retrieved in near real-time at one-minute intervals to produce performance metrics that measure cumulative miles of congestion per route, per entire Metropolitan Statistical Area (MSA), and on coast-to-coast Interstates using speed profile analysis. Moreover, both real-time and historic archival performance measures can be used for after-action analysis of major traffic events. In this study, the traffic congestion for four MSAs and two Interstates during the week of June 28 to July 6 was used as a case study to illustrate the concepts. The study found most congestion in the Chicago, Los Angeles, and New York City metropolitan areas occurred during the PM rush on July 2 before the holiday weekend, with at least 20% of all limited access roadways in each area falling below 40 mph between the hours of 4:30 PM and 5:45 PM local time. On a coast-to-coast level, Interstate 80 showed the heaviest congestion eastbound at 5:15 PM EDT with 140 combined miles of congestion across 11 states. Data reduction and aggregation methods using 15-minute medians outlined in this study allow future systems to implement regional congestion graphs, speed profile charts, and temporal congestion graphs for operational and practical uses. This information can be leveraged by local, regional, and state transportation agencies as well as for media dissemination and outreach to inform the public.

Investigation of the effect of passive vortex inserts of different geometrical shapes on the vibrations reduction efficiency in pipelines with two-phase flow

Scipedia content — Mon, 01 Feb 2021 23:40:00 +0100

This paper describes the experimental test bench used in coolant flow research with application of adjusted optical laser system. It is based on the technology of pulsed particle visualization of micro tracers, i.e. Particle Image Velocimetry (PIV system) that allows for the analysis of the microstructure of the hydrodynamic liquid flow passed through the vortex inserts. Optical measurement (PIV-method) of hydro- and aerodynamic characteristics of the coolant flow allowed obtaining the velocity distribution in straight and various curved sections of the pipeline in order to reliably define the vortex formation condition and the occurrence of the pressure gradient on the outer and inner walls of the curved sections. This gives us the opportunity to verify the calculation models describing the problem of passive control (decrease) of the displacement of pipelines of power equipment, and thus to improve the reliability and safe operation of the system in general. © 2017 The Authors, published by EDP Sciences.

Assessing the Impact of Operational Constraints on the Near-Term Unmanned Aircraft System Traffic Management Supported Market

Scipedia content — Mon, 01 Feb 2021 23:26:38 +0100

CARMENES: data flow

Scipedia content — Mon, 01 Feb 2021 23:24:33 +0100

CARMENES, the new Calar Alto spectrograph especially built for radial-velocity surveys of exoearths around M dwarfs, is a very complicated system. For reaching the goal of 1 m/s radial-velocity accuracy, it is appropriate not only to monitor stars with the best observing procedure, but to monitor also the parameters of the CARMENES subsystems and safely store all the engineer and science data. Here we describe the CARMENES data flow from the different subsystems, through the instrument control system and pipeline, to the virtual-observatory data server and astronomers.

Literature review of research on scour propagation below the submarine pipeline

Scipedia content — Mon, 01 Feb 2021 23:09:53 +0100

Keywords: Scour propagation, Submarine pipeline, Method, Measurement Abstract: The scour process is closely related to the damage and failure of pipelines, so the study of the flow field around pipelines and the sediment transport below pipelines is especially important. Furthermore, the effects of scour propagation below submarine pipelines especially around span shoulders have significant meaning for the study of hydraulics and sediment transport in the ocean. In this paper, investigations in this area are considered and summarized with respect to the different methods of studying the mechanisms: experiment and numerical simulation. The main achievements are presented and compared. The majority of these achievements were derived from experiments because of the lack of a precise theory of sediment transport below pipelines and the difficulties of generating numerical simulations. The different devices used to monitor the scour process are discussed in this paper, and a new way of measuring the scour process is proposed which can be used in laboratory experiments.

Impact of New Transport Infrastructure on Walking, Cycling, and Physical Activity

Scipedia content — Mon, 01 Feb 2021 23:04:21 +0100

Introduction: Walking and cycling bring health and environmental benefits, but there is little robust evidence that changing the built environment promotes these activities in populations. This study evaluated the effects of new transport infrastructure on active commuting and physical activity. Study design: Quasi-experimental analysis nested within a cohort study. Setting/participants: Four hundred and sixty-nine adult commuters, recruited through a predominantly workplace-based strategy, who lived within 30 kilometers of Cambridge, United Kingdom and worked in areas of the city to be served by the new transport infrastructure. Intervention: The Cambridgeshire Guided Busway opened in 2011 and comprised a new bus network and a traffic-free walking and cycling route. Exposure to the intervention was defined using the shortest distance from each participant’s home to the busway. Main outcome measures: Change in weekly time spent in active commuting between 2009 and 2012, measured by validated 7-day recall instrument. Secondary outcomes were changes in total weekly time spent walking and cycling and in recreational and overall physical activity, measured using the validated Recent Physical Activity Questionnaire. Data were analyzed in 2014. Results: In multivariable multinomial regression models—adjusted for potential sociodemographic, geographic, health, and workplace confounders; baseline active commuting; and home or work relocation—exposure to the busway was associated with a significantly greater likelihood of an increase in weekly cycle commuting time (relative risk ratio=1.34, 95% CI=1.03, 1.76) and with an increase in overall time spent in active commuting among the least active commuters at baseline (relative risk ratio=1.76, 95% CI=1.16, 2.67). The study found no evidence of changes in recreational or overall physical activity. Conclusions: Providing new sustainable transport infrastructure was effective in promoting an increase in active commuting. These findings provide new evidence to support reconfiguring transport systems as part of public health improvement strategies. JP is supported by a National Institute for Health Research (NIHR) post-doctoral fellowship (PDF- 2012-05-157). EH is supported by an NIHR Public Health Research project grant (see below) and DO is supported by the Medical Research Council [Unit Programme number MC_UP_12015/6]. RM is funded by the Higher Education Funding Council for England. The Commuting and Health in Cambridge Study was initially funded under the auspices of the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence. Funding from the British Heart Foundation, Economic and Social Research Council, Medical Research Council, National Institute for Health Research and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. The study is now funded by the National Institute for Health Research Public Health Research programme (project number 09/3001/06). The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the NIHR PHR programme or the Department of Health This is the final version of the article. It was first available from Elsevier via http://dx.doi.org/10.1016/j.amepre.2015.09.021

Document type: Article

Software-Defined mobile backhaul for future Train to ground Communication services

Scipedia content — Mon, 01 Feb 2021 23:00:58 +0100

International audience; Software Defined Networking (SDN) has attracted tremendous interest in the telecommunication industry due to its ability to abstract, manage and dynamically re-configure end-to-end networks from a centralized controller. Though SDN is considered to be a suitable candidate for various use cases in mobile networks, none of the work so far has discussed its advantages and actual realization for Train-to-Wayside Communication System (TWC). In this paper, for the first time, the architecture and use cases of SDN controlled mobile backhauling framework for TWC is proposed. We discuss how our proposed architecture can efficiently handle mobility management and also provide dynamic quality-of-service (QoS) for different services on board. As a first step, a software prototype is developed using industrial standard OpenDayLight SDN controller to have our architecture evaluated. Since the automotive sector is being considered to be an important driver for 5G network, our SDN based mobile backhauling solution can be positioned in 5G where SDN plays an important role.

Evaluation of stress-strain state and in-service repair of a damaged pipeline

Scipedia content — Mon, 01 Feb 2021 22:49:30 +0100

During the operation and servicing of hydrocarbons transmission pipelines, a plenty of engineering problems arise. One of them is the repair of various defects in the pipeline, such as defects occurring in welds, damages caused by external mechanical impact, cracks and surface corrosion defects. In the present study, we have considered several problems for the damaged pipeline with one or two volumetric surface defects, subjected to internal pressure loading. In all the cases, it was considered that the defects were caused by surface corrosion and that they were subsequently exposed to a mechanical treatment in order to eliminate the stress concentration effects. The problem of an optimal repair system for a pipe based on its wrapping via laminate composite is considered. The analysis of the most efficient repair wrap properties is performed; some practical recommendations are provided.

Improve round-trip time measurement quality via clustering in inter-domain traffic engineering

Scipedia content — Mon, 01 Feb 2021 22:45:43 +0100

International audience; For multi-homed networks, inter-domain traffic engineering (TE) consists in selecting the best path via available transit providers, so that the transmission quality is improved in front of network events, such as congestion and fail-over. In practice, this choice bases on end-to-end (e2e) measurements toward destination networks. These measurements, especially Round-Trip Time (RTT), are expected to offer an faithful view on inter-domain path properties. Hosts in destination networks with open ports are deliberately discovered for active measurement. RTT traces so obtained can be influenced by host-local factors that are not relevant to inter-domain routing and eventually mislead route decisions. We data-mined the RTT time-series between two ASes with unsupervised learning method - clustering, on a set of statistic features. Achieved results showed that our method was capable of improving data quality, by excluding less reliable traces. Moreover, we considered traceroute measurements. Early results suggested that most variations of e2e delay actually occured in access networks. We thus believe that the proposed scheme can improve the accuracy and stability of the route selection for multi-homed networks.

Vessel Traffic Control Strategy under Complex Weather Conditions for Three Gorges Reservoir

Scipedia content — Mon, 01 Feb 2021 22:42:29 +0100

ontrol Abstract: To ease ship traffic overstock and accidents caused by complex weather in Three Gorges reservoir, the paper took ship traffic organization as the research object. Combined with the features of inland navigation, the paper built up both the safety distance model and safe model for Three Gorges reservoir under complicated weather conditions, which would provide references for safety distance and safety speed control. On the above basis, the paper put forward the specific vessel traffic control strategy including ship speed limit, dynamic ship monitoring, etc., to ensure ship navigation safety and improve management skills under complex weather conditions in Three Gorges reservoir.

The evaluation of cities for environmentally sustainable transport based on DEA method

Scipedia content — Mon, 01 Feb 2021 22:40:24 +0100

Global land transport system ComplexTrans and its contribution to city sustainability

Scipedia content — Mon, 01 Feb 2021 22:35:18 +0100

Statistical Modeling of Corrosion Failures in Natural Gas Transmission Pipelines

Scipedia content — Mon, 01 Feb 2021 22:33:59 +0100

What's in a Name?

Scipedia content — Mon, 01 Feb 2021 22:25:37 +0100

mong the several findings deriving from the application of complex network formalism to the investigation of natural phenomena, the fact that linguistic constructions follow power laws presents special interest for its potential implications for psychology and brain science. By corresponding to one of the most essentially human manifestations, such language-related properties suggest that similar dynamics may also be inherent to the brain areas related to language and associative memory, and perhaps even consciousness. The present work reports a preliminary experimental investigation aimed at characterizing and modeling the flow of sequentially induced associations between words from the English language in terms of complex networks. The data is produced through a psychophysical experiment where a word is presented to the subject, who is requested to associate another word. Complex network and graph theory formalism and measurements are applied in order to characterize the experimental data. Several interesting results are identified, including the characterization of attraction basins, association asymmetries, context biasing, as well as a possible power-law underlying word associations, which could be explained by the appearance of strange loops along the hierarchical structure underlying word categories.

Comment: 5 pages, 6 figures, 3 table

Document type: Preprint

Workshop on Human Machine Interaction in Autonomous Vehicles

Scipedia content — Mon, 01 Feb 2021 22:24:28 +0100

The challenges related to the development of automated vehicles are not only of a technical nature, but also affect the quality of on-board interaction. The role of the HMI is crucial to manage unexpected events and ensure a safe and smooth transition of control. The workshop will promote and discuss the approach used in the HMI design for autonomous vehicles realized from the European projects ADAS&ME and AutoMate. ADAS&ME is dedicated to the creation of new driver state adaptive ADAS that incorporate driver/rider state, the situational and environmental context, as well as the adaptive interaction to automatically transfer control. AutoMate will enhance safety by using the strength of both the automation and driver in a dynamic situation dependent way. In the workshop the main challenges emerged in the projects will be discussed with the audience, to obtain feedbacks and enhancements, and to highlight themes and strategies not yet emerged.

Modeling and Simulation of Passenger Traffic in a National Airport

Scipedia content — Mon, 01 Feb 2021 22:23:49 +0100

Optimal operation of a country's air transport infrastructure plays a major role in the economic development of nations. Due to the increasing use of air transportation in today's world, flights' boarding times have become a concern for both airlines and airports, thus the importance of knowing beforehand how changes in flights demand parameters and physical airport layout will affect passengers flow and boarding times. This paper presents a pedestrian modeling study in which a national airport passenger flow was analyzed. The study was conducted at Vanguardia National Airport in Villavicencio, Meta, Colombia. Different effects of structural changes are shown and provide judging elements for decision makers regarding passenger traffic in airport design.

Comment: 8 pages, submitted to LACCEI 2016

Exploration and Practice of Training Excellent Engineers of Traffic Engineering via School-enterprise Cooperation

Scipedia content — Mon, 01 Feb 2021 22:22:36 +0100

nalyzed domestic and foreign education situation and development trend in excellent engineers training, and explained the significance and necessity of exploration and practice of traffic engineering excellent engineers training program. Combined with the actual situation of Chinese higher education, we explored ways, teaching methods, training programs and practical results to traffic engineering excellence engineers training program.

An Improved MFD based Regional Traffic Volume Dynamic Control

Scipedia content — Mon, 01 Feb 2021 22:21:30 +0100

The connection between traffic congestion and regional demand has become a consensus. A reasonable road network inflow control is essential to prevent the occurrence of congestion. With a consideration of deployment of detectors, an improved macroscopic fundamental diagram-based traffic volume dynamic control method via the feedback control is proposed in this study. Based on OD distribution of trips and connectivity of nodes, a novel method is adopted to identify the key nodes, on which the detectors are laid. And Artificial Neural Network is adopted to predict traffic volume of those sections without detectors. As a case study, the proposed methodology is applied to the regional Road network which is located in downtown area of Nanning, China. Adequate survey and analysis are carried out under current road traffic conditions via simulation study. It is proved that the regional traffic volume dynamic control can ensure steady and orderly regional traffic flow, and enhance the mobility in a saturated traffic conditions.

Innovation in air transport market: impact on competitors strategies

Scipedia content — Mon, 01 Feb 2021 22:17:08 +0100

International audience; The objective of this empirical paper is to analyze the impact of an innovation in air transport system on airlines competitive behavior. We consider as innovation, the use of an aircraft with a significant higher capacity: the Airbus 380. Does the use of the A380 by an airline on a particular route give incentives to competitors to introduce as well this type on aircraft on the same route? To answer this question we use some econometric methods to estimate the impact of the introduction of the A380 by an airline, on the probability that airline’s competitors will follow up the innovation. Controlling for others factors which might impact the choice of innovation, we show that the use of the A380 by an airline on a route gives incentives to competitors to introduce it as well

Instrumenting smartphones with portable NIRS

Scipedia content — Mon, 01 Feb 2021 22:13:11 +0100

In this paper we propose a mobile sensing solution that uses Near Infrared Spectroscopy (NIRS) and discuss its potential in future everyday use cases. The proposed design enables novice end users to classify various objects using NIRS and without prior knowledge of the technology itself. We describe how an instrument that traditionally has been used solely by trained lab personnel, can be commoditized to be used by any end user with a mobile device. The preliminary results indicate that samples can be identified with high accuracy, but that a series of implementation and design challenges must be first accounted for.

Large Scale SfM with the Distributed Camera Model

Scipedia content — Mon, 01 Feb 2021 22:00:49 +0100

We introduce the distributed camera model, a novel model for Structure-from-Motion (SfM). This model describes image observations in terms of light rays with ray origins and directions rather than pixels. As such, the proposed model is capable of describing a single camera or multiple cameras simultaneously as the collection of all light rays observed. We show how the distributed camera model is a generalization of the standard camera model and describe a general formulation and solution to the absolute camera pose problem that works for standard or distributed cameras. The proposed method computes a solution that is up to 8 times more efficient and robust to rotation singularities in comparison with gDLS. Finally, this method is used in an novel large-scale incremental SfM pipeline where distributed cameras are accurately and robustly merged together. This pipeline is a direct generalization of traditional incremental SfM; however, instead of incrementally adding one camera at a time to grow the reconstruction the reconstruction is grown by adding a distributed camera. Our pipeline produces highly accurate reconstructions efficiently by avoiding the need for many bundle adjustment iterations and is capable of computing a 3D model of Rome from over 15,000 images in just 22 minutes.

Comment: Published at 2016 3DV Conference

DC Fast-charging stations for EVs controlled by a local battery storage in low voltage grids

Scipedia content — Mon, 01 Feb 2021 21:53:10 +0100

Electric Vehicles (EVs) are representing a great opportunity for major car manufacturers to invest resources in new technologies in order to support sustainable transportation and the reduction of CO 2 emissions, in particular in the metropolitan areas. In recent years, the increasing penetration of EVs and their charging systems are going through a series of changes. This paper addresses the design of a new DC Fast Charging Station (DCFCS) for EVs coupled with a local Battery Energy Storage (BES) by using the IEC 15118, which provides a communication interface among different actors. DCFCS is equipped with a bidirectional AC/DC converter for feeding power back to the grid, two lithium batteries and a DC/DC converter. The proposed solution decreases the charging time of EVs and facilitates the integration of fast chargers in existing low voltage (LV) grids. The charging station can also be used as a multifunctional grid-utility for ancillary services such as primary frequency control, load levelling and congestion management.

ADAS Virtual Prototyping using Modelica and Unity Co-simulation via OpenMETA

Scipedia content — Mon, 01 Feb 2021 21:45:40 +0100

utomotive control systems, such as modern Advanced Driver Assistance Systems (ADAS), are becoming more complex and prevalent in the automotive industry. Therefore, a highly-efficient design and evaluation methodology for automotive control system development is required. In this paper, we propose a closed-loop simulation framework that improves ADAS design and evaluation. The proposed simulation framework consists of four tools: Dymola, Simulink, OpenMETA and Unity 3D game engine. Dymola simulates vehicle dynamics models written in Modelica. Simulink is used for vehicle control software modeling. OpenMETA provides horizontal integration between design tools. OpenMETA also has the capability to improve design efficiency through the use of PET (Parametric Exploration Tool) and DSE (Design Space Exploration) tools. Unity provides the key functionality to enable interactive, or closed-loop ADAS simulation, which contains sensor models for ADAS, road environment models and provides visualization.

A model-based eco-routing strategy for electric vehicles in large urban networks

Scipedia content — Mon, 01 Feb 2021 21:39:47 +0100

International audience; A novel eco-routing navigation strategy and energy consumption modeling approach for electric vehicles are presented in this work. Speed fluctuations and road network infrastructure have a large impact on vehicular energy consumption. Neglecting these effects may lead to large errors in eco-routing navigation, which could trivially select the route with the lowest average speed. We propose an energy consumption model that considers both accelerations and impact of the road infrastructure, also separating the costs of all the possible turning movements in the transportation network by means of the adjoint graph. The approach makes use of only aggregated data available from existing map services. We demonstrate that the proposed strategy is more effective and reliable than the existing approaches in predicting vehicle energy consumption and in suggesting an energy-efficient route.

Machine learning from experience feedback on accidents in transport

Scipedia content — Mon, 01 Feb 2021 21:39:19 +0100

International audience; In addition to identifying safety deficiencies evidenced by accidents, the independent investigative body makes recommendations to eliminate or reduce these deficiencies. Its main purpose is to advance transportation safety by conducting investigations of accidents in rail and other modes of transportation. He must answer several questions: what happened, why did it happen, and what can be done to reduce the risk of it happening again? In this process, one of the difficulties involved is finding abnormal accident scenarios which are capable of generating a specific hazard. This paper proposes an original method based on machine learning to assist investigators experts in their crucial task of analysis and assessment of the safety for railway transport systems in France. This contribution is based on the use of artificial intelligence techniques and has involved the development of several approaches and tools which assist in the modeling, storage and assessment of knowledge about safety. The proposed approach has two objectives, firstly to record and store experience concerning safety analyses, and secondly to assist those involved in the development and assessment of the systems in the demanding task of evaluating safety studies.

Societal goals, STI policies and socio-technical transitions : the case of the Dutch smart mobility policy

Scipedia content — Mon, 01 Feb 2021 21:27:33 +0100

This research explores the potential value of incorporating a transition perspective in terms of goal setting, rationales, and instruments used in STI policies using the smart mobility policy in the Netherlands as a case study.

Based on Flight Departure Queuing Problem for Terminal Area Capacity Assessment

Scipedia content — Mon, 01 Feb 2021 21:21:02 +0100

In recent years, along with the high-speed growth of national economy, the total turnover of scheduled air transportation in China has risen to number five and passenger turnover rose to Number four in the world. Flight departure queuing occurs mainly in the terminal control area and this is an important part for causing flight delays. To improve the effectiveness of assessment for the departure flight which in the terminal control area, according to the air traffic flow queuing feature, considering estimate departure time, apron, wake turbulence, adopting an algorithm with improved first come first serve to build simulation models to assess the simulation situation for reducing flight delays. Take an example of terminal area of Wuhan Tianhe International Airport, it chooses a flight plan of one day to simulate the daily operation. Simulation results show that using first come first serve algorithm for departure flight can reduce delays, increase airport capacity and improve runway utilization. Keywords-terminal area; departure flight; aircraft; capacity evaluation; queue

Urban Public Transport Financial Supporting Policies Study in China

Scipedia content — Mon, 01 Feb 2021 21:19:00 +0100

With the rapid development of Chinese cities and economy, public transport demand is increasing rapidly, urban public transport priority development has become the focus of the China's transportation development policy. However, Chinese public transport supply and the huge demand for public transportation can't match. China has not established a sustainable financial support mechanism for urban public transportation. Urban public transportation infrastructure investment and operating loss are also needed to be compensated by the central and local government. In this paper, on the basis of analyzing the current situation of the development of urban public transportation in China, from the standpoint of legislation, the local financial support system, the central financial support system and cost-price linkage mechanism, a sustainable subsidy mechanism of Chinese urban public transport should be established in order to further promote the development of Chinese urban public transport.

Route optimization for offloading congested meter fixes

Scipedia content — Mon, 01 Feb 2021 21:16:00 +0100

The Optimized Route Capability (ORC) concept proposed by the FAA facilitates traffic managers to identify and resolve arrival flight delays caused by bottlenecks formed at arrival meter fixes when there exists imbalance between arrival fixes and runways. ORC makes use of the prediction capability of existing automation tools, monitors the traffic delays based on these predictions, and searches the best reroutes upstream of the meter fixes based on the predictions and estimated arrival schedules when delays are over a predefined threshold. Initial implementation and evaluation of the ORC concept considered only reroutes available at the time arrival congestion was first predicted. This work extends previous work by introducing an additional dimension in reroute options such that ORC can find the best time to reroute and overcome the ‘first-come-first-reroute’ phenomenon. To deal with the enlarged reroute solution space, a genetic algorithm was developed to solve this problem. Experiments were conducted using the same traffic scenario used in previous work, when an arrival rush was created for one of the four arrival meter fixes at George Bush Intercontinental Houston Airport. Results showed the new approach further improved delay savings. The suggested route changes from the new approach were on average 30 minutes later than those using other approaches, and fewer numbers of reroutes were required. Fewer numbers of reroutes reduce operational complexity and later reroutes help decision makers deal with uncertain situations.

Blind Signal Separation Algorithm for Space-based ADS-B

Scipedia content — Mon, 01 Feb 2021 21:11:27 +0100

utomatic Dependent Surveillance Broadcast (ADS-B) is a main technology for Air Traffic Management (ATM). As a trend of aerial surveillance, space-based ADS-B uses satellite to receive ADS-B signals to realize aerial surveillance globally. The space-based ADS-B has a series of new features that Terrestrial-based doesn't have including wider coverage, lower SNR, less power difference between signals. These new features make ADS-B signals collisions at the receiver more severe. This paper proposes a model of ADS-B signals collision pattern at the satellite based on poisson process model. This model makes the separation algorithm focus on several collision situations. This paper proposes the iterative projecting algorithm (IPA). IPA uses iteration and projecting algorithm which has less computation complexity and is more suitable for the hardware to perform. Through simulation IPA has similar performance but much lower complexity compared with other ADS-B BSS algorithms in satellite channel.

The influence of direct stray current on the corrosion performance of buried oil pipeline

Scipedia content — Mon, 01 Feb 2021 21:02:11 +0100

Fibbing in action

Scipedia content — Mon, 01 Feb 2021 21:01:04 +0100

Video streaming, in conjunction with social networks, have given birth to a new traffic pattern over the Internet: transient, localized traffic surges, known as flash crowds. Traditional traffic-engineering methods can hardly cope with these surges, as they are unpredictable by nature. Consequently, networks either have to be over-provisioned, which is expensive and wastes resources, or risk to periodically incur congestion, which infuriates customers. This demonstration shows how Fibbing can improve network performance and preserve users’ quality of experience when accessing video streams, by implementing a fine-grained load-balancing service. This service leverages two unique features of Fibbing: programming per destination load-balancing and implementing uneven splitting ratios.

CAP: Collaborative advanced planning, trade-off between airspace management and optimized flight performance: Demonstration of En-Route reduced airspace congestion through collaborative flight planning

Scipedia content — Mon, 01 Feb 2021 20:59:16 +0100

International audience; High demand of flights on elementary air traffic control sectors results in high delays, extra-fuel burn and CO2 emissions, and may also lead to safety issues due to the destabilization of the aviation network. This paper presents a new control strategy approach to keep control of the current flight demand in European busiest sectors (Reims, Paris and Marseille sectors). Flow management positions in Area Control Centers suggest to airline operations centers delay-free routes for the most capacity impeding flights within the French airspace. Instead of spreading flight demand over time, this innovative approach aims at spreading the demand in space, relying on local expertise and enhanced collaboration. The trials conducted from July to September 2015 proved to be beneficial for airlines operations with more than 12,000 minutes of delay saved compared to summer 2014 while traffic increased by more than 6% from 9h to 13h UTC. Following Airport-Collaborative Decision Making, the Collaborative Advanced Planning process paves the way for the En-Route Collaborative Decision Making concept.

Agent Based Monitoring for Smart Cities: Application to Traffic Lights

Scipedia content — Mon, 01 Feb 2021 20:58:11 +0100

International audience; Traffic congestion in large cities became a huge problem, which can lead to a lot of losses especially at the human and material levels. This paper proposes a decentralized model based on multi-agent systems (MAS) and complex event processing (CEP). The new control scheme aims to improve green light time in order to reduce the average waiting time of vehicles in front of the traffic light, especially if the road is empty, and to reduce congestion at crossroad. This improvement is provided by the observation of the intersection through Cyber Physical Systems (CPS). This paper propose an auto-adaptive model for smart regulation traffic lights. The developed model will be evaluated and analyzed using different metrics and scenarios so as to test their influence on system performance.

Analyse architecturale des performances des Processeurs LEON synthétisées sur FPGA

Scipedia content — Mon, 01 Feb 2021 20:54:11 +0100

International audience; Modern embedded processors have gone through multiple internal optimization to speed-up the average execution time e.g., caches, pipelines, branch prediction. Besides, internal communication mechanisms and shared resources like caches or buses have a significant impact on Worst-Case Execution Times (WCETs). Having an accurate estimate of a WCET is now a challenge. Probabilistic approaches provide a viable alternative to single WCET estimation. They consider WCET as a probabilistic distribution associated to uncertainty or risk.In this paper, we present synthetic benchmarks and associated analysis for several LEON3 configurations on FPGA targets. Benchmarking exposes key parameters to execution time variability allowing for accurate probabilistic modeling of system dynamics. We analyze the impact of architecture-level configurations on average and worst-case behaviors.; Les processeurs embarqués modernes sont passés par optimisation interne multiple pour accélérer l'exécution moyenne par exemple le temps, les caches, les pipelines, la prédiction de branchement. Par ailleurs, mécanismes de communication et de partage des ressources comme des caches ou bus ont un impact significatif sur le temps d'exécution pire des cas (WCETs). Avoir une estimation précise d'un WCET est maintenant en défi. Les approches probabilistes fournies pour des alternatives viables à Singles WCET estimation. Ils considèrent comme un WCET probabiliste la distribution associée à l'incertitude ou le risque du pire cas.Dans cet article, nous présentons des benchmarks synthétiques et associés analyse pour plusieurs configurations LEON3 sur FPGA cibles. Benchmarking expose l'effet de certains paramètres sur la variabilité de l'exécution des taches afin de permettre à la modélisation probabiliste précise de la dynamique du système. Nous analysons l'impact des configurations sur les comportements moyens et pire cas du systeme.

SCENARIOS OF TERRITORIAL TRANSFORMATION OF AN ITALIAN ALPINE AREA: THE PROVINCE OF BELLUNO

Scipedia content — Mon, 01 Feb 2021 20:52:39 +0100

Research on the Development of China's Urban Development Based on the Ecological Concept of Low-carbon

Scipedia content — Mon, 01 Feb 2021 20:50:33 +0100

Keywords: Low-carbon, Urban, Environment, Ecological concept Abstract. The rapid progress of urbanization in China will be an important event that will affect the economic and social development of China and the world. The development of low-carbon eco city should study the low carbon eco city development strategy, determine the development of low-carbon eco city, follow the city function and low-carbon eco city development, rational development of city industry; scientific planning, reasonable guide the development of low-carbon eco city planning, improve the index system, the implementation of the planning EIA to ensure sustainable development of the city; at the same time sustainable transportation system comprehensive guidance city energy efficient operation, the construction of sustainable city traffic system; research on energy saving technology promotion, the promotion of green building technology and clean production technology, to provide technical support for the development of low-carbon eco city; promote the system innovation, the reform of the taxation system and evaluation system, and create a system environment for the development of low-carbon eco city, reform the administrative management system of city government, city government function transformation and optimization, to promote the development of low-carbon eco city.

Research of Reliability Assessment of Air Traffic Management Automation Equipment

Scipedia content — Mon, 01 Feb 2021 20:44:05 +0100

Evaluation model. Abstract. To solve the issue that there is some lack of subjectivity and objectivity in the Traditional reliability assessment of air traffic management evaluation means and by analyzing and finding out the related and essential factors in the reliability assessment process of air traffic management equipment, a fuzzy level comprehensive evaluation model can be established and reliability levels of the control equipment are Quantized .SoW that the reliability and evaluation credibility of the equipment are improved. According to the examples below, it turns out that the solution referred can reduce the subject bias in the assessment process, so the result of assessment is more logical, scientific and normative relatively.

Resuming manual control or not? Modeling choices of control transitions in full-range adaptive cruise control

Scipedia content — Mon, 01 Feb 2021 20:38:52 +0100

Automated vehicles and driving assistance systems such as adaptive cruise control (ACC) are expected to reduce traffic congestion, accidents, and levels of emissions. Field operational tests have found that drivers may prefer to deactivate ACC in dense traffic flow conditions and before changing lanes. Despite the potential effects of these control transitions on traffic flow efficiency and safety, most mathematical models evaluating the impact of ACC do not adequately represent that process. This research aimed to identify the main factors influencing drivers' choice to resume manual control. A mixed logit model that predicted the choice to deactivate the system or overrule it by pressing the gas pedal was estimated. The data set was collected in an on-road experiment in which 23 participants drove a research vehicle equipped with full-range ACC on a 35.5-km freeway in Munich, Germany, during peak hours. The results reveal that drivers were more likely to deactivate the ACC and resume manual control when approaching a slower leader, when expecting vehicles cutting in, when driving above the ACC target speed, and before exiting the freeway. Drivers were more likely to overrule the ACC system by pressing the gas pedal a few seconds after the system had been activated and when the vehicle decelerated. Everything else being equal, some drivers had higher probabilities to resume manual control. This study concludes that a novel conceptual framework linking ACC system settings, driver behavior characteristics, driver characteristics, and environmental factors is needed to model driver behavior in control transitions between ACC and manual driving.

Unsupervised aircraft trajectories clustering: a minimum entropy approach

Scipedia content — Mon, 01 Feb 2021 20:35:22 +0100

Best paper award; International audience; Clustering is a common operation in statistics. When data considered are functional in nature, like curves, dedicated algorithms exist, mostly based on truncated expansions on Hilbert basis. When additional constraints are put on the curves, like in applications related to air traffic where operational considerations are to be taken into account, usual procedures are no longer applicable. A new approach based on entropy minimization and Lie group modeling is presented here, yielding an efficient unsupervised algorithm suitable for automated traffic analysis. It outputs cluster centroids with low curvature, making it a valuable tool in airspace design applications or route planning. Keywords–curve clustering; probability distribution estimation; functional statistics; minimum entropy; air traffic management. I. INTRODUCTION Clustering aircraft trajectories is an important problem in Air Traffic Management (ATM). It is a central question in the design of procedures at takeoff and landing, the so called sid-star (Standard Instrument Departure and Standard Terminal Arrival Routes). In such a case, one wants to minimize the noise and pollutants exposure of nearby residents while ensuring runway efficiency in terms of the number of aircraft managed per time unit. The same question arises with cruising aircraft, this time the mean flight path in each cluster being used to optimally design the airspace elements (sectors and airways). This information is also crucial in the context of future air traffic management systems where reference trajectories will be negotiated in advance so as to reduce congestion. A special instance of this problem is the automatic generation of safe and efficient trajectories, but in such a way that the resulting flight paths are still manageable by human operators. Clustering is a key component for such tools: major traffic flows must be organized in such a way that the overall pattern is not too far from the current organization, with aircraft flying along airways. The classification algorithm has thus not only to cluster similar trajectories but at the same time make them as close as possible to operational trajectories. In particular, straightness of the flight segments must be enforced, along with a global structure close to a graph with nodes corresponding to merging/splitting points and edges the airways.

Rationales and instruments for a STI policy from a socio-technical transition perspective

Scipedia content — Mon, 01 Feb 2021 20:28:43 +0100

Astro-H data analysis, processing and archive

Scipedia content — Mon, 01 Feb 2021 20:26:37 +0100

o-H (Hitomi) is an X-ray/Gamma-ray mission led by Japan with international participation, launched on February 17, 2016. The payload consists of four different instruments (SXS, SXI, HXI and SGD) that operate simultaneously to cover the energy range from 0.3 keV up to 600 keV. This paper presents the analysis software and the data processing pipeline created to calibrate and analyze the Hitomi science data along with the plan for the archive and user support. These activities have been a collaborative effort shared between scientists and software engineers working in several institutes in Japan and USA.

A one dimensional numerical approach for computing the eigenmodes of elastic waves in buried pipelines

Scipedia content — Mon, 01 Feb 2021 20:24:35 +0100

Ultrasonic guided waves are often used in the detection of defects in oil and gas pipelines. It is common for these pipelines to be buried underground and this may restrict the length of the pipe that can be successfully tested. This is because acoustic energy travelling along the pipe walls may radiate out into the surrounding medium. Accordingly, it is important to develop a better understanding of the way in which elastic waves propagate along the walls of buried pipes, and so in this article a numerical model is developed that is suitable for computing the eigenmodes for uncoated and coated buried pipes. This is achieved by combining a one dimensional eigensolution based on the semi-analytic finite element (SAFE) method, with a perfectly matched layer (PML) for the infinite medium surrounding the pipe. This article also explores an alternative exponential complex coordinate stretching function for the PML in order to improve solution convergence. It is shown for buried pipelines that accurate solutions may be obtained over the entire frequency range typically used in long range ultrasonic testing (LRUT) using a PML layer with a thickness equal to the pipe wall thickness. This delivers a fast and computationally efficient method and it is shown for pipes buried in sand or soil that relevant eigenmodes can be computed and sorted in less than one second using relatively modest computer hardware. The method is also used to find eigenmodes for a buried pipe coated with the viscoelastic material bitumen. It was recently observed in the literature that a viscoelastic coating may effectively isolate particular eigenmodes so that energy does not radiate from these modes into the surrounding [elastic] medium. A similar effect is also observed in this article and it is shown that this occurs even for a relatively thin layer of bitumen, and when the shear impedance of the coating material is larger than that of the surrounding medium.

Application of the situational management methods to ensure safety in intelligent transport systems

Scipedia content — Mon, 01 Feb 2021 20:22:29 +0100

Copyright © 2017 by SCITEPRESS-Science and Technology Publications, Lda. All rights reserved. The article shows directions of intellectualization of vehicles, analyzed issues and ways to improve safety, reliability and sustainability of transport systems. Methods of situational management are shown. They are based on intelligent technologies for improving safety of complex technical systems. Development and application of precedent expert systems is actual for systems with incomplete information and high complexity of object of management. Such systems reflect decisions by analogy, i.e. according to reports of critical situations, which are potentially dangerous for this object. The object-oriented case model describing the dynamics of dangerous conditions object is developed. Measures on prevention, localization and mitigation of dangerous conditions (such as identification of the dangerous conditions, identify their causes, the safety evaluation, forecasting of development scenarios) are envisaged.

Citywide traffic congestion estimation with social media

Scipedia content — Mon, 01 Feb 2021 20:17:17 +0100

Conventional traffic congestion estimation approaches require the deployment of traffic sensors or large-scale probe vehicles. The high cost of deploying and maintaining these equipments largely limits their spatial-temporal coverage. This paper proposes an alternative solution with lower cost and wider spatial coverage by exploring traffic related information from Twitter. By regarding each Twitter user as a traffic monitoring sensor, various real-time traffic information can be collected freely from each corner of the city. However, there are two major challenges for this problem. Firstly, the congestion related information extracted directly from real-time tweets are very sparse due both to the low resolution of geographic location mentioned in the tweets and the inherent sparsity nature of Twitter data. Secondly, the traffic event information coming from Twitter can be multi-typed including congestion, accident, road construction, etc. It is non-trivial to model the potential impacts of diverse traffic events on traffic congestion. We propose to enrich the sparse real-time tweets from two directions: 1) mining the spatial and temporal correlations of the road segments in congestion from historical data, and 2) applying auxiliary information including social events and road features for help. We finally propose a coupled matrix and tensor factorization model to effectively integrate rich information for Citywide Traffic Congestion Eestimation (CTCE). Extensive evaluations on Twitter data and 500 million public passenger buses GPS data on nearly 700 mile roads of Chicago demonstrate the efficiency and effectiveness of the proposed approach.

Situational impairments to mobile interaction in cold environments

Scipedia content — Mon, 01 Feb 2021 20:10:04 +0100

We evaluate the situational impairments caused by cold ambient temperature on fine-motor movement and vigilance during mobile interaction. For this purpose, we tested two mobile phone applications that measure fine motor skills and vigilance in controlled temperature settings. Our results show that cold adversely affected participants’ fine-motor skills performance, but not vigilance. Based on our results we highlight the importance of correcting measurements when investigating performance of cognitive tasks to take into account the physical element of the tasks. Finally, we identify a number of design recommendations from literature that can mitigate the adverse effect of cold ambiance on interaction with mobile devices.

Cyber-physical systems: A framework for dynamic traffic light control at road intersections

Scipedia content — Mon, 01 Feb 2021 20:09:44 +0100

Traffic control at road intersections is based on traffic lights (TLs). The control mechanism typically used for traffic lights operates based on a periodic schedule to change the light (red/yellow/green). In many cases, a different schedule is used in late night/early morning hours. This fixed control mechanism does not adequately account for changing traffic conditions, and is unaware of/unresponsive to congestion. In this work, we propose a framework for dynamic traffic light control at intersections. The framework relies on a simple sensor network to collect traffic data and includes novel protocols for traffic flow control to handle congestion and facilitate flow. We show that our proposed algorithms have low overhead and are practical to employ in live traffic flow scenarios. Through extensive simulations, we demonstrate the benefits of our framework in optimizing traffic flow metrics, such as traffic throughput, average vehicle waiting time, and vehicle waiting line length.

Planning Under Uncertainty for Aggregated Electric Vehicle Charging with Renewable Energy Supply

Scipedia content — Mon, 01 Feb 2021 20:06:42 +0100

Renewable energy sources introduce uncertainty regarding generated power in smart grids. For instance, power that is generated by wind turbines is time-varying and dependent on the weather. Electric vehicles will become increasingly important in the development of smart grids with a high penetration of renewables, because their flexibility makes it possible to charge their batteries when renewable supply is available. Charging of electric vehicles can be challenging, however, because of uncertainty in renewable supply and the potentially large number of vehicles involved. In this paper we propose a vehicle aggregation framework which uses Markov Decision Processes to control electric vehicles and deals with uncertainty in renewable supply. We present a grouping technique to address the scalability aspects of our framework. In experiments we show that the aggregation framework maximizes the profit of the aggregator, reduces cost of customers and reduces consumption of conventionally-generated power.

Reduction of errors when estimating emissions based on static traffic model outputs

Scipedia content — Mon, 01 Feb 2021 19:58:23 +0100

The rapid growth of traffic congestion has led to an increased level of emissions and energy consumption in urban areas. Well designed infrastructure and traffic controllers along with more efficient vehicles and policy measures are required to mitigate congestion and thus reduce transport emissions. In order to evaluate how changes in the traffic system affect energy use and emissions, traffic analysis tools are used together with emission models. In large urban areas emission models mainly rely on aggregated outputs from traffic models, such as the average link speed and flow. Static traffic models are commonly used to generate inputs for emission models, since they can efficiently be applied to larger areas with relatively low computational cost. However, in some cases their underlying assumptions can lead to inaccurate predictions of the traffic conditions and hence to unreliable emission estimates. The aim of this paper is to investigate and quantify the errors that static modeling introduces in emission estimation and subsequently considering the source of those errors, to suggest and evaluate possible solutions. The long analysis periods that are commonly used in static models, as well as the static models’ inability to describe dynamic traffic flow phenomena can lead up to 40 % underestimation of the estimated emissions. In order to better estimate the total emissions, we propose the development of a post processing technique based on a quasi-dynamic approach, attempting to capture more of the excess emissions created by the temporal and spatial variations of traffic conditions.

Look-Ahead Information Based Optimization Strategy for Hybrid Electric Vehicles

Scipedia content — Mon, 01 Feb 2021 19:54:45 +0100

Local scour around two subsea pipelines in an oscillatory flow

Scipedia content — Mon, 01 Feb 2021 19:48:57 +0100

In offshore engineering, wave generated flows are generally modelled as oscillatory flows when flow around small scale cylindrical structures are considered. The understanding of local scour around subsea pipelines under waves is important to ensure the stability of pipelines. In this study, local scour around two identical pipelines in a tandem arrangement in an oscillatory flow is investigated numerically. The flow around the pipelines is simulated by the Reynolds-averaged Navier-Stokes (RANS) equations and the local scour is predicted by solving the conservation equation of the sediment mass. The numerical model is firstly validated against experimental data. Then, the effects of the gap between the two pipelines and the KC number on the scour depth below the pipelines are examined over a wide parameter space.

Routing strategy including time and carbon dioxide emissions: effects on network performance

Scipedia content — Mon, 01 Feb 2021 19:47:28 +0100

Traffic congestion leads to delays and increased carbon dioxide (CO2) emissions. Traffic management measures such as providing information on environmental route costs have been proposed to mitigate congestion. Multi-criteria routing dynamic traffic assignment (MCR-DTA) models are needed to evaluate the effectiveness of such measures. This paper presents a simulation-based bi-level optimization method to solve the MCR-DTA problem, which works as follows. Route costs include travel times and emissions, but those are updated inside two different loops. In the inner loop, emission costs are considered fixed; the assignment is performed by updating route travel times, using a traditional DTA tool. Then, in the outer loop, emissions are calculated based on link loads and fed back to the DTA tool, which performs a new assignment. The MCR user equilibrium is found when emissions or predefined generalized costs converge to an equilibrium. The bi-level method is first tested on a small network, showing that the proposed method is able to effectively solve the MCR-DTA problem. Next, the method is applied to a medium-size urban network. The results show that if drivers choose routes based on emissions besides travel time, the average travel time and emissions per vehicle decrease. This occurs because congested links have a higher impact on route costs; hence the equilibrium is pushed away from the single-criteria routing (SCR) user optimum towards the SCR system optimum. Results support the conclusion that informing drivers about CO2 emissions per route can potentially lead to decreased delay and emissions in real networks.

Scour patterns below pipelines and scour hole expansion rate

Scipedia content — Mon, 01 Feb 2021 19:46:05 +0100

This paper presents the results of an experimental study on the onset of scour and the propagation of scour hole on the cross-section of a partially buried pipeline under a unidirectional current with uniform sediment. A specially designed device including a transparent pipeline with a mini underwater camera installed inside it is utilized to observe and record the whole scour process. The scour below the pipeline can be divided into an integral scour pattern and a partial scour pattern. In both patterns, the seepage force is the main cause of the onset of scour. However, the scour hole expansion process is driven by the seepage force in the integral scour pattern, while in the partial scour pattern it is driven by the bed shear stress. The effects of pipeline embed-ment, flow depth and the averaged flow velocity on the averaged cross-section expansion rate of the scour hole are also evaluated.

Assessing the impact of aviation security on cyber power

Scipedia content — Mon, 01 Feb 2021 19:40:29 +0100

We analyse the impact of new wireless technology threat models on cyber power, using the aviation context as an example. The ongoing move from traditional air traffic control systems such as radar and voice towards enhanced surveillance and communications systems using modern data networks causes a marked shift in the security of the aviation environment. Implemented through the European SESAR and the US American NextGen programmes, several new air traffic control and communication protocols are currently being rolled out that have been in the works for decades. Unfortunately, during their development the shifting wireless technology threat models were not taken into account. As technology related to digital avionics is getting more widely accessible, traditional electronic warfare threat models are fast becoming obsolete. This paper defines a novel and realistic threat model based on the up-to-date capabilities of different types of threat agents and their impact on a digitalised aviation communication system. After analysing how the changing technological environment affects the security of aviation technologies, current and future, we discuss the reasons preventing the aviation industry from quickly improving the security of its wireless protocols. Among these reasons, we identify the existing tradition of the industry, the prevalence of legacy hard- and software, major cost pressures, slow development cycles, and a narrow focus on safety (as opposed to security). Finally, we analyse how this major technological shift informs the future of cyber power and conflict in the aviation environment by looking at tangible effects for state actors.

Mitigate the load sharing of segment routing for SDN green traffic engineering

Scipedia content — Mon, 01 Feb 2021 19:39:15 +0100

National audience; This research paper proposes IEEE802.3az incorporated green algorithmic schemes on the software defined networking-based segment routing (SDN-based SR) centralized network. The proposed schemes are the green (i.e. the EAGER and CARE metrics) SDN-based SR networks with and without traffic engineering (TE) tunneling. Green metrics extend the IEEE 802.3az energy saving to the whole network, while tunneling avoids the load sharing mechanism included in the segment routing that is not convenient for energy saving purpose. The findings of emulation revealed that the energy efficiency under the EAGER-tunneling strategy is comparable to the conventional metric with TE tunneling, and the saving realized under the CARE-tunneling scheme is twofold in comparison with the LEGACY-tunneling strategy. Meanwhile, the energy saving performance achieved with all three metrics under TE non-tunneling was inferior to those with tunneling. Nonetheless, the lower end-to-end delay and lower maximum link utilization (MLU) were achievable with the non-tunneling strategy.

An Evolutionary Learning Approach to Self-configuring Image Pipelines in the Context of Carbon Fiber Fault Detection

Scipedia content — Mon, 01 Feb 2021 19:23:44 +0100

Carbon fiber reinforced plastics (CFRP) play a key role for the production of leightweight structures. Simultaneously, online quality inspection of CFRP becomes more important, especially for environments with high safety standards. In this context, vision systems aim to find defects of different shape, size, contour and orientation. Little effort, however, has been made in detecting defect areas in images taken from the surface of carbon fibers. A common approach for segmenting filament defects are edge detection and thresholding. With every change of material and process adjustments, the filter parameters have to be adapted. In this paper, we propose a cartesian genetic programming (CGP) approach to semi-automatically select the best parameters. This strategy saves time for parameter identification while at the same time increases precision. A test run on randomly selected samples shows how the approach can substantially improve detection reliability.

Residual Stress State of X65 Pipeline Girth Welds Before and After Local and Furnace Post Weld Heat Treatment

Scipedia content — Mon, 01 Feb 2021 16:30:13 +0100

This research investigated the effects of global (in other words, furnace-based) and local post weld heat treatment (PWHT) on residual stress (RS) relaxation in API 5L X65 pipe girth welds. Two pipe spools were fabricated using identical pipeline production procedures for manufacturing multi-pass narrow gap welds. Non-destructive neutron diffraction strain scanning was carried out on girth welded pipe spools and stress-free comb samples and also thin slices for the determination of lattice spacing. All residual stress measurements were carried out at the KOWARI strain scanning instrument at the Australian Nuclear Science and Technology Organization (ANSTO)."/jats:p" "jats:p"Residual stresses of two pipe spools (in the as-welded condition) were measured through the thickness in the weld material and adjacent parent metal starting from the weld toe. Three line-scans were completed 3mm below outer surface, at mid thickness and 3mm above the inner surface. PWHT was adopted for stress relaxation; one pipe was conventionally heat treated entirely in an enclosed furnace and the other was locally heated by a flexible ceramic heating pad. Residual stresses were measured after PWHT at exactly the same locations as those used for the as-welded condition. Residual stress states of the two pipe spools in as-welded condition and after PWHT were compared and the results were presented in full stress maps. Additionally, through thickness residual stress profiles and the results of one line scan (3mm below outer surface) were compared with the respective residual stress profiles advised in British Standard BS 7910 “Guide to methods for assessing the acceptability of flaws in metallic structures” and the UK nuclear industry’s R6 procedure. The residual stress states of the two pipe spools measured in the as-welded condition were similar. With the given parameters, local PWHT has effectively reduced residual stresses in the pipe spool to such a level that it prompted the thought that local PWHT can be considered a substitute for global PWHT.

Emergent Behaviour of Trajectory Based Operations Under Very High En-route Traffic Demand

Scipedia content — Mon, 01 Feb 2021 16:29:08 +0100

Effective collaboration between planning controller, tactical controller and pilots in handling various uncertainties and hazards is the result of decades of evolutionary development. The forthcoming paradigm shift to Trajectory Based Operations (TBO) requires a similarly effective collaboration between the TBO layer and a tactical layer. Through agent-based modelling and simulation the authors have recently shown that in a pure airborne self-separation environment these two layers together can yield remarkably positive emergent behaviour in managing uncertainties and hazards, as a result of which very high en-route traffic demands can safely be accommodated. The current paper addresses the question if similarly good emergent behaviour is feasible with a ground based TBO design. The key findings are twofold. A negative finding is that ground-based TBO is not providing the remarkably positive emergent behaviours of pure airborne TBO. Though a positive finding is that ground-based TBO has the potential to safely accommodate high en route traffic demands.