Scipedia: Documents published in 2016

Performance comparison of guidance strategies to accomplish RTAs during a CDO

Scipedia content — Wed, 03 Feb 2021 17:05:03 +0100

© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

Best student paper award 36th DASC

Peer Reviewed

Award-winning

Document type: Conference object

A Microscopic Evaluation of Robustness in Critical Points

Scipedia content — Wed, 03 Feb 2021 17:02:35 +0100

One method to increase the quality of railway traffic flow is to construct a more robust timetable in which trains are able to both recover from delays and the delays are prevented from propagating. Previous research results show that the indicator Robustness in Critical Points (RCP) can be used to increase timetable robustness. In this paper we present the use of a method for RCP optimization, how can be implemented and assessed ex-post via microscopic simulation and subsequently evaluated. From the evaluation we learn more about how increased RCP values influence a timetable’s performance. The aim is to understand more about RCP increase at a localised level within a timetable in terms of effects to the pairs of trains that are part of the indicator. We present a case study where an initial timetable and a timetable with increased RCP values are evaluated. The ex-post evaluation includes the quantification of measures concerning train-borne delay and robustness of traffic flow, as well as measures capturing the subsequent quality of service experienced by passengers to assess the broader effects of improved robustness. The result shows that it is necessary to use several Key Performance Indicators (KPIs) to evaluate the effects of an RCP increase. The robustness will increase at a localised level, but the results also indicate that there is a need to analyse the relationship between ex-post measures and RCP further, to improve the method used to increase RCP and thus its overall effect on timetable robustness.

Viability and potential demand capitation of urban freight tramway systemss via demand-supply modelling and cost benefit analysis

Scipedia content — Wed, 03 Feb 2021 16:53:10 +0100

International audience; This paper presents a general framework to assess urban rail logistics suitability via a socio-economic cost benefit analysis. Firstly, we propose an overview on the basic notions of CBA and SCBA. Secondly, we identify and present the main types of costs and benefits or railway urban logistics services and the related final delivery services using low emission road vehicles to serve customers where the rail systems cannot. Thirdly, as an example of application, we propose to assess a scenario of deployment of a freight tramway in Paris, in a possible configuration. The results show the potential of those approaches but also show that it is important to contextualize them and inform the different users about their real capacities.

Current looping NEXRAD is inadequate for hazardous-weather flight

Scipedia content — Wed, 03 Feb 2021 16:50:23 +0100

Next-Generation Radar (NEXRAD) is an important decision-support tool for air traffic control (ATC). It is currently being introduced into aircraft cockpits, and will be equally important for remote piloting of unmanned aerial systems (UAS). Unfortunately, numerous studies strongly suggest that manually estimation of closest point of approach (CPA) to heavy weather is a difficult task for pilots, and that current-generation NEXRAD may be intrinsically inadequate for that task. In this study, we begin with an ecological information analysis of the looping NEXRAD format itself, and show that inherent task difficulty is predicted mathematically and by the neural structure of the visual system. Then, to confirm empirically, we develop a mathematical model of an extremely simple “ideal storm” to generate various types of simulated weather cells. A looping NEXRAD-type part-task simulation is created, and 21 general aviation (GA) pilots are tested to measure effects of weather system depth (19 vs. 40 nm), and the opening and closing of gaps at various closure rates between weather cells (−14, −7, 0, 7, 14 kt). For the values tested, weather system depth has no significant effect on eventual CPA from heavy weather ("40 dBZ reflectivity). However, redesign and retesting may be warranted for this variable. In contrast, weather movement clearly and greatly degrades safety. It does not seem to matter if weather movement is as slow as 7 scale kt, nor whether gaps are opening or closing. Any weather movement makes an already hard task harder. We can now say with certainty that current-generation looping NEXRAD is inadequate to manually keep aircraft safely separated from weather. Ecological analysis indicates necessity of adding 30–45 minutes of future-predicted (forecast) weather and a 20 nm range ring to the looping NEXRAD display to enable safe tactical weather avoidance.

StarDock: shipping customized computing environments to the data

Scipedia content — Wed, 03 Feb 2021 16:47:44 +0100

Surging data volumes make it increasingly unfeasible to transfer astronomical datasets to the local systems of individual scientists. Centralized pipelines offer some relief, but lack flexibility to fulfill the needs of all users. We have developed a system that leverages the Docker container application virtualization software. Along with a suite of commonly used astronomy applications, users can configure a container with their own custom software and analysis tools. Our StarDock system will move the users container to the data, and expose the requested dataset, allowing our users to safely and securely process their data without needlessly transferring hundreds of gigabytes.

Novel solar tower structure to lower plant cost and construction risk

Scipedia content — Wed, 03 Feb 2021 16:45:12 +0100

In recent times the interest in solar tower power plants is increasing with various plants being built in the last years and currently under construction, e.g. Ivanpah and Crescent Dunes in the US and Khi Solar One in South Africa. The higher cycle efficiency leads to lower levelised cost of electricity. However, further cost reductions are required and this paper compares a novel and patented solar tower structure with a conventional concrete tower. The novel solar tower design is cable-stayed which has the benefit that the cables absorb a large part of the wind and buckling loads. A tower that has to cope with fewer wind and buckling forces can have a significantly smaller diameter than a concrete tower, which enables workshop manufacture, sea and road transport, and rapid on-site installation. The case study provided in this paper finds that the tower area affected by wind can be reduced by up to 45%, installation time shortened by up to 66%, and tower cost by 20-40%. The novel design allows the constr...

New Classification Approach for Dents With Metal Loss and Corrosion Along the Seam Weld

Scipedia content — Wed, 03 Feb 2021 16:44:25 +0100

The ability to characterize metal loss and gouging associated with dents and the identification of corrosion type near the longitudinal seam are two of the remaining obstacles with in-line inspection (ILI) integrity assessment of metal loss defects. The difficulty with denting is that secondary features of corrosion and gouging present very different safety and serviceability scenarios; corrosion in a dent is often not very severe while metal loss caused by gouging can be quite severe. Selective seam weld corrosion (SSWC) along older low frequency electric resistance welding (ERW) seams also presents two different integrity scenarios; the ILI tool must differentiate the more serious SSWC condition from the less severe conventional corrosion which just happens to be near a low frequency ERW seam. Both of these cases involve identification difficulties that require improved classification of the anomalies by ILI to enhance pipeline safety."/jats:p" "jats:p"In this paper, two new classifiers are presented for magnetic flux leakage (MFL) tools since this rugged technology is commonly used by pipeline operators for integrity assessments. The new classifier that distinguishes dents with gouges from dents with corrosion or smooth dents uses a high and low magnetization level approach combined with a new method for analyzing the signals. In this classifier, detection of any gouge signal is paramount; the conservatism of the classifier ensures reliable identification of gouges can be achieved. In addition to the high and low field data, the classifier uses the number of distinct metal loss signatures at the dent, the estimated maximum metal loss depth, and the location of metal loss signatures relative to dent profile (e.g. Apex, Shoulder)."/jats:p" "jats:p"The new classifier that distinguishes SSWC from corrosion near the longitudinal weld uses two orientations of the magnetic field, the traditional axial field and a helical magnetic field. In this classifier, detection of any long narrow metal loss is paramount; the conservatism of the classifier ensures that high identification of SSWC can be achieved. The relative amplitude of the corrosion signal for the two magnetization directions is an important characteristic, along with length and width measures of the corrosion features."/jats:p" "jats:p"These models were developed using ILI data from pipeline anomalies identified during actual inspections. Inspection measurements from excavations as well as pipe removed from service for lab analysis and pressure testing were used to confirm the results.

A Human-in-the-loop Evaluation of a Coordinated Arrival/Departure Scheduling Operations for Managing Departure Delays at LaGuardia Airport

Scipedia content — Wed, 03 Feb 2021 16:43:37 +0100

LaGuardia (LGA) departure delay was identified by the stakeholders and subject matter experts as a significant bottleneck in the New York metropolitan area. Departure delay at LGA is primarily due to dependency between LGA's arrival and departure runways: LGA departures cannot begin takeoff until arrivals have cleared the runway intersection. If one-in one-out operations are not maintained and a significant arrival-to-departure imbalance occurs, the departure backup can persist through the rest of the day. At NASA Ames Research Center, a solution called "Departure-sensitive Arrival Spacing" (DSAS) was developed to maximize the departure throughput without creating significant delays in the arrival traffic. The concept leverages a Terminal Sequencing and Spacing (TSS) operations that create and manage the arrival schedule to the runway threshold and added an interface enhancement to the traffic manager's timeline to provide the ability to manually adjust inter-arrival spacing to build precise gaps for multiple departures between arrivals. A more complete solution would include a TSS algorithm enhancement that could automatically build these multi-departure gaps. With this set of capabilities, inter-arrival spacing could be controlled for optimal departure throughput. The concept was prototyped in a human-in-the- loop (HITL) simulation environment so that operational requirements such as coordination procedures, timing and magnitude of TSS schedule adjustments, and display features for Tower, TRACON and Traffic Management Unit could be determined. A HITL simulation was conducted in August 2014 to evaluate the concept in terms of feasibility, controller workload impact, and potential benefits. Three conditions were tested, namely a Baseline condition without scheduling, TSS condition that schedules the arrivals to the runway threshold, and TSS+DSAS condition that adjusts the arrival schedule to maximize the departure throughput. The results showed that during high arrival demand period, departure throughput could be incrementally increased under TSS and TSS+DSAS conditions without compromising the arrival throughput. The concept, operational procedures, and summary results were originally published in ATM20151 but detailed results were omitted. This paper expands on the earlier paper to provide the detailed results on throughput, conformance, safety, flight time/distance, etc. that provide extra insights into the feasibility and the potential benefits on the concept.

A flexible platform for intermodal transportation and integrated logistics

Scipedia content — Wed, 03 Feb 2021 16:43:23 +0100

This paper proposes an application of Information and Communications Technology (ICT) tools and Internet of Things to support intermodal transport and integrated logistics. In particular, the design and development of a new ICT platform is presented in order to facilitate the connectivity of the logistics systems, applications or objects from stakeholders to any logistics collaborative environment. The proposed platform aims to i) provide technological solutions to enhance and simplify collaboration among actors along the supply chain; ii) adopt and provide core functionalities to improve, optimise and automate transport and logistics operations within supply collaborations; iii) simplify information exchange within an integrated security framework. Finally, we show a case study in order to enlighten the effectiveness of the proposed ICT platform.

1st workshop on situational awareness in semi-Automated vehicles

Scipedia content — Wed, 03 Feb 2021 16:41:25 +0100

This workshop will focus on the problem of occupant and vehicle situational awareness with respect to automated vehicles when the driver must take over control. It will explore the future of fully automated and mixed traffic situations where vehicles are assumed to be operating at level 3 or above. In this case, all critical driving functions will be handled by the vehicle with the possibility of transitions between manual and automated driving modes at any time. This creates a driver environment where, unlike manual driving, there is no direct intrinsic motivation for the driver to be aware of the traffic situation at all times. Therefore, it is highly likely that when such a transition occurs, the driver will not be able to transition either safely or within an appropriate period of time. This workshop will address this challenge by inviting experts and practitioners from the automotive and related domains to explore concepts and solutions to increase, maintain and transfer situational awareness in semi-Automated vehicles. The organisers acknowledge the financial assistance provided under a range of projects from FNR Luxembourg (CS14/IS/8301419) and FWF Austria (I 2126-N15)

Dynamic Analysis of Variable Speed Limit Control for Traffic Accident Management

Scipedia content — Wed, 03 Feb 2021 16:40:00 +0100

two-lane cellular automaton model is developed to investigate the effects of variable speed limit (VSL) control strategy on alleviating accident induced congestion and improving traffic efficiency. The impact of accident duration on traffic dynamics are analyzed by counting the downstream discharge flow rates and drawing the spatial-temporal diagram. The effectiveness of VSL control strategy is then investigated. The simulation results indicate that the longer the accident duration, the more serious the traffic congestion and the lower the system discharge flow rates are; with appropriate speed limit value and speed limit region length, traffic congestion induced by accident can be alleviated and even the system discharge flow can be increased in some extend.

Estimation and cancellation of interferences in automotive radar signals

Scipedia content — Wed, 03 Feb 2021 16:37:13 +0100

Radar sensors become typical components for automotive driver assistance systems and autonomous driving. The widespread use of this sensor type leads to an increasing risk of unwanted interferences. Those interferences can severely degrade the detection performance and cause sensor blindness. To overcome this problem, this paper describes a method to estimate and remove interfering signals in data of chirp sequence modulated radars. The estimation is derived theoretically and applied on simulation and measurement data.

New optimization and security approaches to enhance the Smart Grid performance and reliability

Scipedia content — Wed, 03 Feb 2021 16:36:37 +0100

International audience; Nowadays, the Smart Grid (SG) is becoming smarter thanks to the integration of different information and communication technologies to enhance the reliability and efficiency of the power grid. However, several issues should be met to ensure high SG performance. Among these issues, we cite the problem of electric vehicles (EVs) integration into the SG to avoid electricity intermittence due to the important load that EVs can create. Another issue is the SG communication network security that can be attempted by malicious intruders in order to create damages and make the power grid instable. In this context, we propose at a first level a Bayesian game-theory model that aims to integrate optimally EVs into the SG and maintain the equilibrium between the offer and the demand. At a second level, we propose an Intrusion Detection System (IDS) to protect the SG from attacks that aim to disturb the state estimation. Numerical results prove the efficiency and robustness of our proposed models.

Private Development of Road and Air Transport Market from Romania – Implications for the Economy

Scipedia content — Wed, 03 Feb 2021 16:33:53 +0100

Model predictive current control of a proposed single-switch three-level active rectifier applied to EV battery chargers

Scipedia content — Wed, 03 Feb 2021 16:32:15 +0100

This paper presents a model predictive current control applied to a proposed new topology of single-switch three-level (SSTL) active rectifier, which is exemplified in an application of single-phase battery charger for electric vehicles (EVs). During each sampling period, this current control scheme selects the state of the SSTL active rectifier that minimizes the error between the grid current and its reference. Using this strategy it is possible to obtain sinusoidal grid currents with low total harmonic distortion and unitary power factor, which is one of the main requirements for EVs chargers. The paper presents in detail the principle of operation of the SSTL active rectifier, the digital control algorithm and the EV battery charger (where is incorporated the SSTL active rectifier) that was used in the experimental verification. The obtained experimental results confirm the correct application of the model predictive current control applied to the proposed SSTL active rectifier. This work was supported in part by the FCT–Fundação para a Ciência e Tecnologia in the scope of the project: PEst UID/CEC/00319/2013. Vítor Monteiro was supported by the scholarship SFRH/BD/80155/2011 granted by the FCT agency.

Experimental prototype for remote tower systems design

Scipedia content — Wed, 03 Feb 2021 16:31:13 +0100

Small and medium-sized airports are poorly occupied or occupied for a small period of time, hence the remote control towers are a good solution to control air traffic in these airports. A surveillance and monitoring air traffic prototype has been built to test surveillance, control and visualization concepts. The prototype is comprised of a hybrid real-synthetic scenario using augmented reality techniques to evaluate the operation of the surveillance/vision systems, observing the behavior of this system with different targets, backgrounds, inclement weather, etc. and helping the design/experimentation of novel control procedures in the airport area. This allows the analysis of risky situations and the controller training without putting at risk neither people nor material goods.

Document type: Conference object

A real-time radio transient pipeline for ARTS

Scipedia content — Wed, 03 Feb 2021 16:30:43 +0100

RTS is a new instrument designed to discover transient astronomical sources in the radio spectrum. To operate, it will require a high-performance radio transient pipeline, capable of processing hundreds of data streams in real-time, at a data rate of 36 GB/s. What makes the processing of these data streams challenging is the fact that radio signals received from space are dispersed by the interaction with the inter-stellar medium, and dispersion is a function of the distance between source and receiver. Because the distance of yet to discover objects is not known in advance, every data stream needs to be processed for thousands of trial distances, an extremely time consuming process. In this paper we introduce and describe a prototype for the ARTS radio transient pipeline. Our proposed pipeline is highly parallel and uses Graphics Processing Units as accelerators for its computational kernels. We test the pipeline on two different and widely used GPUs, the HD7970 from AMD and the K20X from NVIDIA, and show linear scalability and real-time performance on both. Using these performance results, we provide an estimate on the size of the system necessary to implement ARTS, and a lower bound on its power consumption. The results of this paper are also relevant in the context of designing the Square Kilometer Array.

Exact and Heuristic Algorithms for Runway Scheduling

Scipedia content — Wed, 03 Feb 2021 16:29:21 +0100

Assessment of road transport infrastructure in Osogbo, Osun State, Nigeria

Scipedia content — Wed, 03 Feb 2021 16:28:07 +0100

The growth and progress of a society is determined and measured to a large extent by the socio-economic development of the city. This is largely dependent on the transportation system of the area. Transportation promotes development in any area and when transportation is hindered, development is also retarded. In Nigeria, and Osogbo, Osun State Capital in particular, the only available mode of transportation is road transport. It provides the linkages between spatially separated facilities, enable social contact, and access to employments. Road infrastructure is a critical ingredient of economic development in the study area. The demands for road transport infrastructure in Nigeria over the years have increased tremendously, while the supplies of road transport services have declined grossly. There is a miss-merge between the demand and supply of road infrastructure in the study area. The study therefore, assessed the availability and adequacy of road transport infrastructure in Osogbo. The study was carried out through personal observation and direct measurement of the available road infrastructure in the study area. The study surveyed 101 kilometres of roads, of which about 77% of the roads are characterized with potholes and about 88% of the roads are without walkways which does not make it safe for pedestrians and about 92% of the roads are without road signs. The study is concluded by suggesting the need for government and public participation in the provision and maintenance of road transport infrastructure in the study area to enhance effective and efficient movement of goods, services and people in the study area.

The causality analysis of air transport and socio-economics factors: the case of OECD countries

Scipedia content — Wed, 03 Feb 2021 16:24:34 +0100

transport is one of the most important industries in the world with its rapid growth, and direct and indirect contribution to world economy. In other words, GDP, tourism and employment are the key factors causing that growth in air transport and an increase in those factors boost the demand for air transport. However, uncertainty in economy, rising unemployment and increased terrorist attacks towards tourism would be a big threat to the growth of air transport in the future. To understand the importance of the mentioned factors, we first aim to apply an econometric approach which is panel Granger causality analysis. To achieve that, data from World Bank data set for OECD countries between the year of 2000 and 2013 is used in this study. We apply Pesaran CDLM test and Friedman’s test which are preferred when the number of units (N) is higher than the time (T) to test cross-sectional dependence and we then perform Granger causality analysis in order to see whether there is a causal relationship (unidirectional or bidirectional) or not among air transport, tourism, economic growth and employment. Econometric results indicate that there is a unidirectional short run causal relationship between economic growth, tourism, employment and air transport and that those factors play an important role in the growth of air transport. In this paper, we also aim to discuss the future challenges for air transport within the frame of econometric results and statistical analysis. Publisher version

Nonlinear model predictive extended eco-cruise control for battery electric vehicles

Scipedia content — Wed, 03 Feb 2021 16:19:44 +0100

International audience; Battery Electric Vehicles are becoming a promising technology for road transportation. However, the main disadvantage is the limited cruising range they can travel on a single battery charge. This paper presents a novel extended ecological cruise control system to increase the autonomy of an electric vehicle by using energy-efficient driving techniques. Driven velocity, acceleration profile, geometric and traffic characteristics of roads largely affect the energy consumption. An energy-efficient velocity profile should be derived based on anticipated optimal actions for future events by considering the electric vehicle dynamics, its energy consumption relations, traffic and road geometric information. A nonlinear model predictive control method with a fast numerical algorithm is adapted to determine proper velocity profile. In addition, a novel model to describe the energy consumption of a series-production electric vehicle is introduced. The hyperfunctions concept is used to model traffic and road geometry data in a new way. The proposed system is simulated on a test track scenario and obtained results reveal that the extended ecological cruise control can significantly reduce the energy consumption of an electric vehicle.

Conflict resolution for wind-optimal aircraft trajectories in North Atlantic oceanic airspace with wind uncertainties

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

traffic in the North Atlantic oceanic airspace (NAT) experiences very strong winds caused by jet streams. Flying wind-optimal trajectories increases individual flight efficiency, which is advantageous when operating in the NAT. However, as the NAT is highly congested during peak hours, a large number of potential conflicts between flights are detected for the sets of wind-optimal trajectories. Conflict resolution performed at the strategic level of flight planning can significantly reduce the airspace congestion. However, being completed far in advance, strategic planning can only use predicted environmental conditions that may significantly differ from the real conditions experienced further by aircraft. The forecast uncertainties result in uncertainties in conflict prediction, and thus, conflict resolution becomes less efficient. This work considers wind uncertainties in order to improve the robustness of conflict resolution in the NAT. First, the influence of wind uncertainties on conflict prediction is investigated. Then, conflict resolution methods accounting for wind uncertainties are proposed.

Micro and macro mechanical analysis of gas pipeline steels

Scipedia content — Wed, 03 Feb 2021 16:12:55 +0100

The actual safety margins of gas pipelines depend on a number of factors that include the mechanical characteristics of the material. The evolution with time of the metal properties can be evaluated by mechanical tests performed at different scales, seeking for the best compromise between the simplicity of the experimental setup to be potentially employed in situ and the reliability of the results. Possible alternatives are comparatively assessed on pipeline steels of different compositions and in different states.

Calculated definition of the technological parameters of butt welding of polyethylene pipes at low temperatures

Scipedia content — Wed, 03 Feb 2021 16:06:28 +0100

The thermal process of welding polyethylene pipes for gas pipelines at temperatures below standard is theoretically studied. The used mathematical model considers the heat of the phase change within the temperature range and the heat effect formed at burr setting. Computing experiments indicate the possibility of regulation by temperature conditions when welding at low ambient air temperature and the possibility of providing the same change of the temperature field as at admissible air temperature in the heat-affected zone.

Multi-agent Systems for Air Traffic Conflicts Resolution by Local Speed Regulation and Departure Delay

Scipedia content — Wed, 03 Feb 2021 16:03:35 +0100

This article won two awards : Best of Session (SE/TFM) Award Best Undergraduate Student Paper Award; International audience; Air Traffic Flow Management (ATFM) aims at structuring traffic in order to reduce congestion in airspace. Congestion being linked to aircraft located at the same position at the same time, ATFM organizes traffic in the spatial dimension (e.g. route network) and/or in the time dimension (sequencing and merging in TMA, Miles-in-Trail for en-route airspace). The objective of this paper is to develop a methodology that allows the traffic to self-organize in the time dimension when demand is high. This structure disappears when the demand diminishes. In order to reach this goal, a multi-agent system has been developed. In this system, aircraft agents regulate speed and delay departure time in order to reduce the number of conflicts, thus decreases overall traffic complexity, which becomes easier to manage by air traffic controllers. This algorithm was applied on realistic examples.

Exploring the bifurcation between sedimentation versus scour onset below pipelines in unidirectional currents

Scipedia content — Wed, 03 Feb 2021 16:01:47 +0100

The onset of tunnel scour beneath offshore pipelines has been previously documented to result from a phenomenon known as piping, in which the hydrodynamic pressure difference across a pipeline causes a sufficient pressure gradient within the soil under the pipe to result in floatation or suspension of downstream sediment particles. The change in propensity for onset of tunnel scour due to sedimentation around the pipe has also been previously noted. This paper explores the potential for predicting the cumulative sedimentation around a pipeline in unidirectional currents using a more fundamental approach than has previously been described in the literature. The results of this approach are compared to model pipeline experiments to see how well the predictions explain the observed changes in sedimentation and the associated effects of sedimentation on the potential for tunnel scour.

Analysis of Neural Network Models in Prediction of Ground Surface Settlement around Deep Foundation Pit

Scipedia content — Wed, 03 Feb 2021 16:00:30 +0100

During the foundation pit excavation,the prediction of ground surface settlement around deep foundation pit is directly related to the safety of the foundation pit excavation, surrounding buildings and pipelines, but the ground surface settlement of foundation pit has the characteristics of nonlinear and fuzzy. So it is necessary to monitor and predict the excavation settlement according to the excavation conditions, the surrounding environment, security level and other buildings around. Neural networkcan simulate any unknown system of complex polygene conveniently and high precision. GRNN and two improved BP neural network prediction models are established to predictsettlement in this paper. The ground surfacesettlement around a deep foundation pit is predicted with all main influential factors being taken into account properly. The three neural network prediction models—GRNN, PSO-BP and GA-BPpredictionmodel are analyzed in principle and network architecture design.And they are used to predict ground surface settlement for an engineering example in Beijing. The prediction results show that neural network have high feasibility and reliabilityin predicting ground surface settlement around deep foundation pit, and neural network will have better application prospect in the field of geotechnical in-situ testing & monitoring.

Cyber Security of Cyber Physical Systems: Cyber Threats and Defense of Critical Infrastructures

Scipedia content — Wed, 03 Feb 2021 15:58:35 +0100

Summary form only. Most critical infrastructures such as the power grid, railway or air traffic control, industrial automation in manufacturing, water/sewage infrastructure, banking system, etc., are cyber physical systems (CPS). Since continued availability of the major functions of these are extremely important for economic and normal lives of people, there is a wide spread concern that these might come under intense cyber attacks. In fact, a number of such cases have occurred in the last decade. Therefore, defending these systems from cyber threats is extremely important. Because of the cyber physical nature of most of these systems, and due to increasing use of networking, embedded computing, and SCADA (Supervisory Control and Data Acquisition) the attack surfaces have grown. In this tutorial, we shall consider some of these cyber threats, discuss the methodologies, tools and techniques for defending such systems, and show how the design of secure cyber physical systems differs from previous design methodologies of CPS systems.

An Integrated Gate Turnaround Management Concept Leveraging Big Data/Analytics for NAS Performance Improvements

Scipedia content — Wed, 03 Feb 2021 15:55:32 +0100

"Gate Turnaround" plays a key role in the National Air Space (NAS) gate-to-gate performance by receiving aircraft when they reach their destination airport, and delivering aircraft into the NAS upon departing from the gate and subsequent takeoff. The time spent at the gate in meeting the planned departure time is influenced by many factors and often with considerable uncertainties. Uncertainties such as weather, early or late arrivals, disembarking and boarding passengers, unloading/reloading cargo, aircraft logistics/maintenance services and ground handling, traffic in ramp and movement areas for taxi-in and taxi-out, and departure queue management for takeoff are likely encountered on the daily basis. The Integrated Gate Turnaround Management (IGTM) concept is leveraging relevant historical data to support optimization of the gate operations, which include arrival, at the gate, departure based on constraints (e.g., available gates at the arrival, ground crew and equipment for the gate turnaround, and over capacity demand upon departure), and collaborative decision-making. The IGTM concept provides effective information services and decision tools to the stakeholders, such as airline dispatchers, gate agents, airport operators, ramp controllers, and air traffic control (ATC) traffic managers and ground controllers to mitigate uncertainties arising from both nominal and off-nominal airport gate operations. IGTM will provide NAS stakeholders customized decision making tools through a User Interface (UI) by leveraging historical data (Big Data), net-enabled Air Traffic Management (ATM) live data, and analytics according to dependencies among NAS parameters for the stakeholders to manage and optimize the NAS performance in the gate turnaround domain. The application will give stakeholders predictable results based on the past and current NAS performance according to selected decision trees through the UI. The predictable results are generated based on analysis of the unique airport attributes (e.g., runway, taxiway, terminal, and gate configurations and tenants), and combined statistics from past data and live data based on a specific set of ATM concept-of-operations (ConOps) and operational parameters via systems analysis using an analytic network learning model. The IGTM tool will then bound the uncertainties that arise from nominal and off-nominal operational conditions with direct assessment of the gate turnaround status and the impact of a certain operational decision on the NAS performance, and provide a set of recommended actions to optimize the NAS performance by allowing stakeholders to take mitigation actions to reduce uncertainty and time deviation of planned operational events. An IGTM prototype was developed at NASA Ames Simulation Laboratories (SimLabs) to demonstrate the benefits and applicability of the concept. A data network, using the System Wide Information Management (SWIM)-like messaging application using the ActiveMQ message service, was connected to the simulated data warehouse, scheduled flight plans, a fast-time airport simulator, and a graphic UI. A fast-time simulation was integrated with the data warehouse or Big Data/Analytics (BAI), scheduled flight plans from Aeronautical Operational Control AOC, IGTM Controller, and a UI via a SWIM-like data messaging network using the ActiveMQ message service, illustrated in Figure 1, to demonstrate selected use-cases showing the benefits of the IGTM concept on the NAS performance.

Modelling Climate Change Effects on Sustainable Transport Facilities through Time Series and Rainfall Trend Analysis of Palapye - Botswana

Scipedia content — Wed, 03 Feb 2021 15:53:22 +0100

HOW TRAVEL DEMAND AFFECTS DETECTION OF NON-RECURRENT TRAFFIC CONGESTION ON URBAN ROAD NETWORKS

Scipedia content — Wed, 03 Feb 2021 15:52:33 +0100

Occurrence of non-recurrent traffic congestion hinders the economic activity of a city, as travellers could miss appointments or be late for work or important meetings. Similarly, for shippers, unexpected delays may disrupt just-in-time delivery and manufacturing processes, which could lose them payment. Consequently, research on non-recurrent congestion detection on urban road networks has recently gained attention. By analysing large amounts of traffic data collected on a daily basis, traffic operation centres can improve their methods to detect non-recurrent congestion rapidly and then revise their existing plans to mitigate its effects. Space-time clusters of high link journey time estimates correspond to non-recurrent congestion events. Existing research, however, has not considered the effect of travel demand on the effectiveness of non-recurrent congestion detection methods. Therefore, this paper investigates how travel demand affects detection of non-recurrent traffic congestion detection on urban road networks. Travel demand has been classified into three categories as low, normal and high. The experiments are carried out on London’s urban road network, and the results demonstrate the necessity to adjust the relative importance of the component evaluation criteria depending on the travel demand level.

Designing future turnouts – where research capabilities meet industry needs

Scipedia content — Wed, 03 Feb 2021 15:43:56 +0100

Railway switches and crossings (S&C) are the most costly items for railway infrastructure managers. In the UK over 20% of the planned maintenance and renewal budget for 2014-19 is taken by S&C despite the fact that they only represent a small proportion of the network in terms of km-installation. They are complicated and expensive assets, representing a bottle neck with potential for costly traffic disruptions while attracting a large proportion of the networks failures (e.g. Point Operating Equipment - POE related). Recent European projects (e.g. Innotrack, Sustrail, Drail, Capacity4Rail) and the new H2020/Shift2Rail opportunities for funding are enabling industry and research institutes to work together with infrastructure managers and suppliers to help rethink and redesign a technology which in some aspects remains truly embedded in the middle of last century. What was then a satisfactory design is now being proven beyond its intended design capacity, with ever increasing loads, traffic speed and frequency; while at the same time the window for maintenance and intervention is being drastically narrowed. \\ud One fundamental aspect emerging from these previous research programmes is that a lot of the observed failures surrounding S&C have their root cause explained by the discontinuities experienced by the vehicle at S&C. The nature of these is related to the varying geometrical interface between the vehicle wheels and the guiding rails (e.g. load transfer between stock and switch rails), as well as the uneven vertical support offered to the vehicle through the S&C (e.g. uneven loading of long bearers, increased bending stiffness of cast crossings). A large number of reliability issues find their source in the physical vibrations and dynamically amplified loads occurring because of these two facts, this includes some of the gradual deterioration experienced by POE. Research institutes, including the Institute of Railway Research at the University of Huddersfield, have helped develop advanced simulation tools capable of confidently predicting these phenomena and assess contributory factors to degradation modes as well as iteratively work on remedial actions. These might either be small step changes to existing designs or they might be radical concept changes, covering short, medium and long term vision for 2050 railways in Europe. The author will summarise some of the outcome of recent EU projects, give examples of were simulation technology might be used to assess future improvements and radical changes, as well as opportunities for validating these and other wheel-rail interface research projects using advanced testing techniques.

Considering knowledge gaps for automated driving in conventional traffic

Scipedia content — Wed, 03 Feb 2021 15:41:40 +0100

—With increasing numbers of vehicles using low level automation and higher level automation expected in the future, significant effects are expected on traffic flow. Despite much simulation and driving simulator research on SAE level 1 vehicles, there remain many questions in regard to the effects of the systems on traffic flow. The effects of higher levels of automation are even more difficult to estimate, as these vehicles are not even present on roads at this time, let alone in sufficient numbers to analyze. In this research, we propose a methodology for a-priori analysis of potential conflict situations: Method for Explorative TRaffic scenario Observation and Analysis (METRO-A). It is applied to the case of automated driving in conventional traffic to analyze potential difficulties that SAE level 3 and 4 and higher vehicles may encounter in mixed traffic conditions, for a weaving section case-study. Furthermore, a set of important research questions are constructed that are relevant for the automotive industry, and road agencies and authoritie

A study on the traffic impact of the road corridors due to flyover construction at Surabaya intersection, Banda Aceh of Indonesia

Scipedia content — Wed, 03 Feb 2021 15:39:56 +0100

The urbanest areas are suffering from unmaintained externalities such as excessive travel time, unnecessary fuel consumption and even serious economic loss due extraordinary growth in automobile traffic (i.e. motorcycle and car), and as consequence of automobile ownership and usage have continued rapid growth into recent days including in Banda Aceh, a capital of Aceh Province. An increasing of automobile usage leads to induce traffic congestion in the city centers including in Surabaya intersection. To counter the negative effects of the congestion, the Government of Aceh (GoA) decided to build a flyover at the congested intersection mentioned above. However, during the construction period, traffic congestion is severe along this corridor, and traffic is randomly distributed to the road network in surrounding construction site without any traffic arrangement by the authority. It is, therefore, this research aims to analyze the traffic impact due to flyover’s construction. The study was conducted at three corridors which are considered as the most congested corridors due to exiting of bottleneck traffic. Those corridors are Teuku Muhammad Hasan Rd., Prof Ali Hasyimi Rd., Tgk. Imum Lueng Bata Rd. The findings from the analysis revealed that the traffic loading has increased accounting up to 34% and 37% for Teuku Muhammad Hasan Rd. and Prof. Ali Hasyimi Rd., respectively. Furthermore, the results of the level of service (LOS) analyses show that dropped in LOS from B to C during the construction period for Teuku Muhammad Hasan Rd. and Prof. Ali Hasyimi Rd.The urbanest areas are suffering from unmaintained externalities such as excessive travel time, unnecessary fuel consumption and even serious economic loss due extraordinary growth in automobile traffic (i.e. motorcycle and car), and as consequence of automobile ownership and usage have continued rapid growth into recent days including in Banda Aceh, a capital of Aceh Province. An increasing of automobile usage leads to induce traffic congestion in the city centers including in Surabaya intersection. To counter the negative effects of the congestion, the Government of Aceh (GoA) decided to build a flyover at the congested intersection mentioned above. However, during the construction period, traffic congestion is severe along this corridor, and traffic is randomly distributed to the road network in surrounding construction site without any traffic arrangement by the authority. It is, therefore, this research aims to analyze the traffic impact due to flyover’s construction. The study was conducted at three...

Experimental application of OMA solutions on the model of industrial structure

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

It is very important and sometimes even vital to maintain reliability of industrial structures. High quality control during production and structural health monitoring (SHM) in exploitation provides reliable functioning of large, massive and remote structures, like wind generators, pipelines, power line posts, etc. This paper introduces a complex of technological and methodical solutions for SHM and diagnostics of industrial structures, including those that are actuated by periodic forces. Solutions were verified on a wind generator scaled model with integrated system of piezo-film deformation sensors. Simultaneous and multi-patch Operational Modal Analysis (OMA) approaches were implemented as methodical means for structural diagnostics and monitoring. Specially designed data processing algorithms provide objective evaluation of structural state modification.

What are the effects of incentives on plug-in electric vehicle sales in Europe?

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

Plug-in electric vehicles (PEV), both as battery electric vehicles (BEV) and plug-in hybrid vehicles (PHEV) have noteworthy potential to reduce global and local emissions. Governments around the world have implemented monetary and non-monetary policies to accelerate PEV market diffusion. However, empirical estimates of their effectiveness are scarce. Here, we analyse data on PEV sales from 30 European countries from 2010–2016 with respect to direct subsidies, tax rebates, and other incentives. We apply panel data regression models and control for several other influencing factors such as income and fuel prices. We find income, diesel prices and both direct and indirect subsidies to positively influence PEV adoption. The aim of the present paper is to contribute to the discussion on policy-aided market evolution using empirical evidence about electric vehicles and alternative fuel vehicles in general.

Mapping deadmalls landscape: how VGI support research and actions on abandoned retail heritage

Scipedia content — Tue, 02 Feb 2021 08:40:07 +0100

Advanced Driver Assistance Systems

Scipedia content — Tue, 02 Feb 2021 08:36:45 +0100

The role of taxes in triggering change in corporate car fleets

Scipedia content — Tue, 02 Feb 2021 08:29:04 +0100

International audience; Corporate car fleets account for 16% of all light-duty vehicles in France, and about 25% of their total CO2 emissions. They also account for 40% of new light-duty vehicle sales, and close to 50% of new battery-electric vehicle sales. Yet, the environmental performance of corporate vehicles differs widely between passenger cars and light commercial vehicles. The former are heavily taxed based on their CO2 emissions under both, the ‘malus’ scheme (environmental penalty upon initial registration) and the TVS scheme (annual circulation tax), whereas the latter are exempt from all CO2-based taxes. On the other hand, both passenger cars and light commercial vehicles in corporate car fleets are eligible to the ‘bonus’ scheme (environmental incentive upon initial registration), and to the registration tax rebates for alternative-fuel vehicles. This paper discusses the influence of tax policy on the CO2 emission levels of, and demand for alternative-fuel vehicles by, corporate car fleets in France. We present the main tax schemes that have a probable influence on the choices of corporations with regards to the CO2 emission levels and drivetrain technology of the vehicles they purchase and use (past and present terms and conditions: scope, tax base, etc.), based on a historical review of tax policies. Besides, we provide a preliminary assessment of the expected effectiveness of the various tax schemes listed, based on the magnitude of the costs (or benefits) they impose on corporations, using a TCO (total costs of ownership) approach. Finally, we discuss the similarities and differences in the terms and conditions of the schemes reviewed, and the relative strength of their incentive effects on corporate car fleets.Through unravelling the complexity of the tax policy framework, we highlight several challenges pertaining to the lack of legibility and/or consistency among tax schemes, and the existence of inertia, which hinder the effectiveness of tax policy in fostering the uptake of low-emission vehicles by corporate car fleets. We argue for an overhaul of the tax policy framework that applies to corporate car fleets, which would provide an opportunity to clarify the objectives of policy-makers with regards to the environmental impacts of fleets, and to design more efficient policies (tax or otherwise).

Modelling the dynamics of driver situation awareness in automated driving

Scipedia content — Tue, 02 Feb 2021 08:28:54 +0100

This study presents a numerical model that describes the dynamic process of building situation awareness after an automation-initiated transition. The model predicts the level of situation awareness as a function of elapsed time since the transition, and is verified using data from an experiment in which participants watched animated video clips of automated driving scenarios. Additionally, the ‘number of fixations per second’ is suggested for real-time monitoring of situation awareness in automated driving.

Aspect-oriented Formal Specification Modeling of Air Traffic Control System

Scipedia content — Tue, 02 Feb 2021 08:28:33 +0100

Constraint satisfaction problem based on flow graph to study the resilience of inland navigation networks in a climate change context

Scipedia content — Tue, 02 Feb 2021 08:24:46 +0100

International audience; The T-Ten European program aims at optimizing the transport logistics in Europe by promoting alternative transport modes. Navigation transport offers a competitive and environmentally friendly alternative. Hence, it is foresaw an increase of the navigation transport demand that it will be necessary to accommodate. This will be very challenging particularly in a global change context where less available water resource is expected. A constraint satisfaction problem based on flow graph is proposed in this paper to study the resilience of inland navigation networks against increase of the navigation demand and extreme events. Drought and flood scenarios are simulated considering an network composed of five interconnected navigation reaches. The results show that the designed tools are well adapted to the resilience study of inland navigation networks.

Airport noise predicts song timing of European birds

Scipedia content — Tue, 02 Feb 2021 08:23:39 +0100

Anthropogenic noise is of increasing concern to biologists and medical scientists. Its detrimental effects on human health have been well studied, with the high noise levels from air traffic being of particular concern. However, less is known about the effects of airport noise pollution on signal masking in wild animals. Here, we report a relationship between aircraft noise and two major features of the singing behavior of birds. We found that five of ten songbird species began singing significantly earlier in the morning in the vicinity of a major European airport than their conspecifics at a quieter control site. As birds at both sites started singing before the onset of air traffic in the morning, this suggests that the birds in the vicinity of the airport advanced their activity to gain more time for unimpaired singing before the massive plane noise set in. In addition, we found that during the day, chaffinches avoided singing during airplane takeoffs, but only when the noise exceeded a certain threshold, further suggesting that the massive noise caused by the airport can impair acoustic communication in birds. Overall, our study indicates that birds may be adjusting their mating signals and time budgets in response to aircraft noise.

Document type: Article

Do new sources of traffic data make the application of Chaos Theory to traffic management a realistic possibility?

Scipedia content — Tue, 02 Feb 2021 08:21:25 +0100

Current signal systems for managing road traffic in many urban areas around the world lack a coordinated approach to detecting the spatial and temporal evolution of congestion across control regions within city networks. This severely inhibits these systems’ ability to detect reliably, on a strategic level, the onset of congestion and implement effective preventative action. As traffic is a time-dependent and non-linear system, Chaos Theory is a prime candidate for application to Urban Traffic Control (UTC) to improve congestion and pollution management. Previous applications have been restricted to relatively uncomplicated motorway and inter-urban networks, arguably where the associated problems of congestion and vehicle emissions are less severe, due to a general unavailability of high-resolution temporal and spatial data that preserve the variability in short-term traffic patterns required for Chaos Theory to work to its full potential. This paper argues that this restriction can now be overcome due to the emergence of new sources of high-resolution data and large data storage capabilities. Consequently, this opens up the real possibility for a new generation of UTC systems that are better able to detect the dynamic states of traffic and therefore more effectively prevent the onset of traffic congestion in urban areas worldwide.

Optimization and simulation based approach for an arrival and departure manager tool

Scipedia content — Tue, 02 Feb 2021 08:20:06 +0100

International audience; This work proposes a methodology for developing an airport arrival and departure manager tool. This methodology employs optimization together with simulation techniques for improving the robustness of the solution. An arrival and departure manager tool is intended to help air traffic controllers in managing the inbound and outbound traffic without incurring in conflicts or delays. In this context, air traffic controllers need to have a tool able to help them to make the right decisions in a short time horizon. The maindecisions taken in the present methodology for each aircraft are: entry time and entry speed in the airspace and push back time at the gate. The objective of this methodology is to have a smooth flow of aircraft both in the airspace and on the ground. Preliminary tests were made using Paris Charles de Gaulle Airport as case study, and the results show that conflicts were sensibly reduced.

Lane Density as Measure of Effectiveness of Multi lane Indian Highways under Heterogeneous Traffic Conditions Traffic Engineering

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

MacroSim: A macroscopic Mobsim for MATSim

Scipedia content — Tue, 02 Feb 2021 08:11:38 +0100

The simulation of large-scale scenarios requires high-performance simulations. MATSim, an agent-based transport simulation, is increasingly reaching limits. The traditional approach is to scale the scenarios, i.e. simulating only 10% of a population instead of 100%. This paper suggests MacroSim, a macroscopic mobility simulation module for MATSim, to overcome the current per- formance limits within MATSim. It uses volume-delay functions to estimate travel times for links based on experienced usages of these links. This allows to decouple agents and thus allows a parallelization of the mobility simulation within MATSim per design. A preliminary implementation of MacroSim showed promising results (7 to 50 times faster than the current mobility simulation depending on the scenario size). Given its limitations - most important no back propagation of traffic congestion - MacroSim is suggested as a complementary mobility simulation to the current implementation for cases where scenario size and simulation performance are more important than precise traffic dynamics. ISSN:1877-0509

CFD analysis of supercritical CO2 used as HTF in a solar tower receiver

Scipedia content — Tue, 02 Feb 2021 08:08:44 +0100

The relative cost of a solar receiver can be minimized by the selection of an appropriate heat transfer fluid capable of achieving high receiver efficiencies. In a conventional central receiver system, the concentrated solar energy is transferred from the receiver tube walls to the heat transfer fluid (HTF), which passes through a heat exchanger to generate steam for a Rankine cycle. Thus, higher working fluid temperature is associated with greater efficiency in receiver and power cycle. Emerging receiver designs that can enable higher efficiencies using advanced power cycles, such as supercritical CO2 (s-CO2) closed-loop Brayton cycles, include direct heating of s-CO2 in tubular receiver designs capable of withstanding high internal fluid pressures (around 20 MPa) and temperatures (900 K). Due to the high pressures required and the presence of moving components installed in pipelines (ball-joints and/or flexible connections), the use of s-CO2 presents many technical challenges due to the compatibility of...

Performance of an Automated System for Control of Traffic in Terminal Airspace

Scipedia content — Tue, 02 Feb 2021 07:57:23 +0100

This paper examines the performance of a system that performs automated conflict resolution and arrival scheduling for aircraft in the terminal airspace around major airports. Such a system has the potential to perform separation assurance and arrival sequencing tasks that are currently handled manually by human controllers. The performance of the system is tested against several simulated traffic scenarios that are characterized by the rate at which air traffic is metered into the terminal airspace. For each traffic scenario, the levels of performance that are examined include: number of conflicts predicted to occur, types of resolution maneuver used to resolve predicted conflicts, and the amount of delay for all flights. The simulation results indicate that the percentage of arrivals that required a maneuver that changes the flight's horizontal route ranged between 11% and 15% in all traffic scenarios. That finding has certain implications if this automated system were to be implemented simply as a decision support tool. It is also found that arrival delay due to purely wake vortex separation requirements on final approach constituted only between 29% and 35% of total arrival delay, while the remaining major portion of it is mainly due to delay back propagation effects.

An adaptive Kalman filter based traffic prediction algorithm for urban road network

Scipedia content — Tue, 02 Feb 2021 07:55:05 +0100

Frequent traffic congestion and gridlocks are causing global economies staggering cost in terms of fuel consumption, time wastage, and public health. To rectify this problem, many advocates combining Information and Communication Technologies (ICT) and traffic engineering concepts for better traffic management. Timely and accurate traffic prediction and management are central to the ICT-based Intelligent Transportation Systems (ITS). In this paper, we presented a traffic prediction model based on Kalman filtering theory, which optimizes the prediction of speed by minimizing the variance between the real-Time speed measurement and its estimation. The prediction model predicts the speed across high-level roadway segments using historical and real-Time speed measurements (spot speed) reported by the vehicles traveling on the urban road network. The performance evaluation of the proposed prediction model includes a number of case studies. Each case study is conducted with different parametric settings to explain the different characteristic of the model. The results show that provided the spot speed measurements don't fluctuate significantly over the time, the proposed model is capable of predicting traffic with 54% more accuracy. This work was made possible by NPRP Grant No.: 8-2459-1-482 from the Qatar National Research Fund (a member of The Qatar Foundation) Scopu

Investigation and performance analysis of OpenVX optimizations on computer vision applications

Scipedia content — Tue, 02 Feb 2021 07:51:35 +0100

The development of Advanced Driver Assistance Systems (ADAS), such as pedestrian detection, requires real-time update rates at high image resolution. Hopefully, heterogeneous architectures with high computing performance have been developed for this purpose. To benefit from this hardware performance, different programming languages and acceleration frameworks have been developed. OpenVX framework provides a graph-based execution model to program image processing algorithms on heterogeneous platforms. In this work, we investigate OpenVX optimizations for computer vision applications. We examine how this framework responds to different data access patterns. We test three important optimizations of OpenVX: kernels merge, data tiling and parallelization via OpenMP. The contribution and the impact of each optimization on different data access pattern are explained.

The Openpipeflow Navier–Stokes solver

Scipedia content — Tue, 02 Feb 2021 07:46:32 +0100

Pipelines are used in a huge range of industrial processes involving fluids, and the ability to accurately predict properties of the flow through a pipe is of fundamental engineering importance. Armed with parallel MPI, Arnoldi and Newton--Krylov solvers, the Openpipeflow code can be used in a range of settings, from large-scale simulation of highly turbulent flow, to the detailed analysis of nonlinear invariant solutions (equilibria and periodic orbits) and their influence on the dynamics of the flow.

Comment: 5 pages, 4 figure

Document type: Article

Transferring urban traveling speed model fits across cities

Scipedia content — Tue, 02 Feb 2021 07:44:07 +0100

Purpose Link traveling time models form the basis for route planning methods used in navigation devices as well as for logistic applications. These models are provided based on extensive real world data sets which are available to a differing degree in different cities as well as for different links within a given city. For smaller cities, where typically fewer data is available or less frequently measured links, it might be beneficial to transfer models from close-by cities or links from the same city with sufficient data basis. In this paper, the potential for transferring link traveling time model fits, that is, the estimated models, between cities and within a city is investigated. Methods that combine information typically contained in street maps with empirically derived features that are easily transferred are developed and tested with substantial real world data sets. This provides the basis for developing route planning methods in cities with insufficient real world data coverage to base accurate route traveling time predictions on. Methods Link traveling time models are derived on the basis of an extensive floating taxi data set in Vienna, Austria. The models incorporate typical map information such as speed limits and functional road classification (frc). Estimation is performed using penalized least squares methods to control for overfitting. The expected accuracy for the model transfer is investigated both in terms of intracity transfer (from modelled links to other links in the same city) and in terms of intercity transfer (from one city to another city). Data sets of different extent are used from the two Austrian cities of Vienna and Linz as well as for the French city of Lyon. Results The models presented in this paper are demonstrated to lead to superior performance compared to the benchmark model of Leodolter et al. (2015). It is shown that transfer between cities in the same country (here using the Vienna model for Linz) may be beneficial in terms of prediction accuracy while the transfer between countries (here from Vienna to Lyon) decreases accuracy but not dramatically. Conclusion These results demonstrate that the transfer of link traveling time models within a city or from one city to another city can provide acceptable prediction accuracy and thus can be used as the basis for navigation algorithms in case no good data basis is accessible for a city.

Document type: Article

KeystoneML: Optimizing Pipelines for Large-Scale Advanced Analytics

Scipedia content — Tue, 02 Feb 2021 07:43:08 +0100

Modern advanced analytics applications make use of machine learning techniques and contain multiple steps of domain-specific and general-purpose processing with high resource requirements. We present KeystoneML, a system that captures and optimizes the end-to-end large-scale machine learning applications for high-throughput training in a distributed environment with a high-level API. This approach offers increased ease of use and higher performance over existing systems for large scale learning. We demonstrate the effectiveness of KeystoneML in achieving high quality statistical accuracy and scalable training using real world datasets in several domains. By optimizing execution KeystoneML achieves up to 15x training throughput over unoptimized execution on a real image classification application.

En iyi konumlandırma için bağlamsal haydut problemleri ile trafik yoğunluğunu öğrenme

Scipedia content — Tue, 02 Feb 2021 07:25:21 +0100

Date of Conference: 15-18 May 2017 Conference Name: IEEE 25th Signal Processing and Communications Applications Conference, SIU 2017 Optimum localization problem, which has a wide range of application areas in real life such as emergency services, command and control systems, warehouse localization, shipment planning, aims to find the best location to minimize the arrival, response or return time which might be vital in some applications. In most of the cases, uncertainty in traffic is the most challenging issue and in the literature generally it is assumed to obey a priori known stochastic distribution. In this study, problem is defined as the optimum localization of ambulances for emergency services and traffic is modeled to be Markovian to generate context data. Unlike the solution methods in the literature, there exists no mutual information transfer between the model and solution of the problem; thus, a contextual multi-armed bandit learner tries to determine the underlying traffic with simple assumptions. The performance of the bandit algorithm is compared with the performance of a classical estimation method in order to show the effectiveness of the learning approach on the solution of the optimum localization problem.

Utilisation de rapports post-incident d'impacts sur voie ferrée pour l'évaluation de la méthode IRIP de cartographie du ruissellement

Scipedia content — Tue, 02 Feb 2021 07:25:06 +0100

FloodRisk, 3rd European Conference on Flood Risk Management, Lyon, FRA, 17-/10/2016 - 21/10/2016; International audience; Indicator of Intense Pluvial Runoff (French Acronym) - is a method to map the susceptibility of territories to surface runoff generation, transfer and accumulation. The method is based on a geomatic combination of landscape factors extracted from topography, land use and soil type. This study is part of the method evaluation process and suggests using information from post-event surveys of surface runoff events to evaluate the agreement between the IRIP maps and the field observations. Surface runoff susceptibility maps are produced at five meters resolution for three impact areas on railways with different infrastructure and environment configurations. First, information categories are extracted from the post-event surveys, and then the IRIP maps are analyzed to see if and how the information categories are retrieved. This study shows that the IRIP maps fit the impact description. The areas susceptible to surface runoff transfer fit the gullies locations and the areas susceptible to surface runoff accumulation fit the sediment deposit traces. The comparison also highlights that the IRIP maps can give further information on the event spatial dynamics. Given the simplicity and the robustness of the mapping method, IRIP can be a tool to perform surface runoff post-event surveys and to improve the surface runoff hazard assessment.

FACTS2: A service oriented simulation framework for aeronautical communication system evaluation

Scipedia content — Tue, 02 Feb 2021 07:19:46 +0100

The modernization of the European air transportation system will increase the need for data communication. This creates the need for large-scale simulations to ascertain that new aeronautical communication systems fulfil the requirements of future air traffic management communication. This paper pre-sents a framework for such simulations based on service-oriented software architecture. The Framework for Aeronautical Communications and Traffic Simulations 2 (FACTS2) is based on the concept of service oriented simulation creating complex simulations from simple software building blocks called "services". Separating the tasks of services appropriately allows for natural parallelization at the service level. FACTS2 was applied to the simulation of European reference air traffic for the years 2007 to 2035 that will provide the basis for future aeronautical communication evaluations. It could be shown that the service-oriented simulation approach offers significant performance gains through parallelization scaling linearly with the number of available CPUs. The air traffic simulation results were validated against published simulation results to verify their correctness.

A Dynamic Heads-Up Air Traffic Locator & Collision Advisory Display Using Google Glass

Scipedia content — Tue, 02 Feb 2021 07:15:16 +0100

First place winner of oral presentations. Presented to the 12th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held at the Heskett Center, Wichita State University, April 29, 2016.

Finding the right RoPax vessel size and freight price. A coste and mode choice model

Scipedia content — Tue, 02 Feb 2021 07:04:47 +0100

[EN] Motorways of the sea operated as RoPax services are natural competitors with only-road freight haulage transportation. Cost, time and quality perceived are the determinants that make transporters and shippers use one route or another. This research considers the role that shipping companies and their ship deployment and pricing strategy have in the equation, as incentives for modal shift from road to sea. A model of the ships and transporter costs is developed considering different business models for the transporter (accompanied versus unaccompanied cargo) followed with a discrete choice model that, once calibrated, allows to test the influence that variables such as frequency, ship size and commercial speed might play into the competitiveness of a shipping line. As a result, different pricing strategies for the shipping line are developed and the characteristics of the optimal shipping line for each of them are found, to either maximize the profit of the shipping company or the modal shift.DOI: http://dx.doi.org/10.4995/CIT2016.2016.4148 http://ocs.editorial.upv.es/index.php/CIT/CIT2016 Morales Fusco, P.; Grau Sala, M.; Saurí Marchán, S. (2016). Finding the right RoPax vessel size and freight price. A coste and mode choice model. Editorial Universitat Politècnica de València. 1456-1470. https://doi.org/10.4995/CIT2016.2015.4148 OCS 1456 1470

Social Sustainability and Smart Mobility : Exploring the relationship

Scipedia content — Tue, 02 Feb 2021 07:03:15 +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

SDN-based Overlay Networks for QoS-aware Routing

Scipedia content — Tue, 02 Feb 2021 07:01:11 +0100

International audience; We propose a SDN-based architecture for distant points in- terconnection through an overlay network. The main goal of the overlay network is to provide with resilient and high- performance interconnection between its nodes, without the need of changing nor handling Internet routers. Our pro- posed architecture benets from the advantages inherited from SDN such as simplicity of management and ow-level Trac Engineering capabilities. In particular, our approach allows to build the overlay network without any tunnelling technology, which promises to provide a gain in terms of performance, and to ease deployment and management. In addition, we address one of the challenges of SDN, by dis- cussing a possible approach for active monitoring in the pro- posed SDN-overlay architecture.

The Optimization of Chinese Air Route Network with Cooperative Coevolving PSO

Scipedia content — Tue, 02 Feb 2021 06:58:13 +0100

With the rapid development of Chinese air transportation, the performance of the Chinese air route network (ARN) becomes more and more important. Since the location of air route waypoints (ARWs) is crucial for the performance of ARN, we propose an ARW optimization model in this paper. In the model, the cooperative coevolving particle swarm optimization (CCPSO) is adopted to optimize the location of ARWs. The simulation results show that CCPSO can effectively decrease the total flight conflict coefficient and improve the performance of the Chinese ARN. Our work will be helpful to better understand and optimize the Chinese air route network. Introduction The air route is the real track that every flight travels from one airport to another. In the air route network (ARN), airports or air waypoints are nodes and links are denoted by the air route segments. Airports are the points that generate and absorb air traffic flow while air waypoints are the points that only transmit traffic flow without generating or absorbing any air traffic flow. There are two kinds of waypoints in ARN, one is the air route waypoints (ARWs) and the other is the crossing waypoints (CWs). An ARW is a navigation marker which keeps the pilots informed about the desired track [1,2], while a CW is a crossing point where two or more aircrafts may encounter with each other. With the rapid development of air transportation, researchers and practitioners have pay great attention in past decades to improve the efficiency and safety of the air transportation system [3,4]. Different models aiming to optimize the performance of ARN have been proposed and some important aspects have been taken into account [5,6], such as flights efficiency, potential conflict and airspace capacity. Siddiquee [5] firstly presented a mathematical model to quantify various attributes of the air route network. Mehadhebi et al. [7] proposed an approach to minimize the total airline cost of the ARN. Zhou et al. [8] proposed a multi-objective optimization algorithm to minimize both airline costs and flight conflicts. Cai et al. [9] proposed a bi-objective optimization model to solve the crossing waypoint location (CWL) problems. Their approach not only reduces the total airline cost (TAC) but also decreases the total flight conflict coefficients (TFCC). Jin et al. [10] proposed a triple-objectives model to solve the CWL problems, where three key factors (flights efficiency, potential conflict and airspace capacity) are investigated. Since the number of ARWs is larger than that of CWs, it is more difficult to optimize the location of ARWs. It is known that the cooperative coevolution (CC) algorithms [11-14] are suitable for solving large-scale optimization problems, and the particle swarm optimization (PSO) is an effective solution to solve complicated optimization problems. Thus, in this paper, we use the cooperative coevolving particle swarm optimization (CCPSO) to optimize the location of ARWs of the Chinese ARN. The rest of this paper is organized as follows. Section 2 describes the CCPSO algorithm in detail. Section 3 presents the ARW optimization model based on the CCPSO. Section 4, simulation results and correspondent theoretical analysis are provided. Finally, we give the including remarks in section 5. 2nd International Conference on Electronics, Network and Computer Engineering (ICENCE 2016) © 2016. The authors Published by Atlantis Press 378 The CCPSO Algorithm The CC algorithms can be regarded as automatic approaches to implement the divide-and-conquer strategy [11-14] and are quite effective for large-scale optimization problems. The particle swarm optimization (PSO) is a nature-inspired algorithm that has shown excellent performance in solving many real optimization problems. The CCPSO is a comprehensive optimization algorithm, where PSO and CC are incorporated together. The framework of CCPSO can be summarized as follows: (1) Problem decomposition: A high-dimensional decision vector is decomposed into some smaller subcomponents. This is a dynamically grouping process, where the variables are selected randomly to form groups and a scheme is used to dynamically determine the size of the coevolving subcomponent variables. (2) Subcomponent optimization: The algorithm of Cauchy and Gaussian PSO is used to optimize the subcomponents. In the algorithm, each swarm is located in a ring topology structure, which is potential to slow down the speed of convergence and maintains the diversity of population. (3) Subcomponents coadaptation: Since interdependencies may exist between subcomponents, coadaptation is essential to capture such interdependencies during the optimization process. It is necessary to combine all subcomponents to a complete decision vector. The best individual from other subpopulations will be used when the objective function is calculated. The ARW Optimization Model Actually, the ARW location optimization problem is a high-dimension problem. The challenge of the location optimization of the ARWs is two-fold: first, a typical problem involves a large number of design variables; second, the objective function is non-differentiable. It is difficult to solve these problems by using traditional optimization algorithms [15-17], which suffer from the “curse of dimensionality”, i.e., the performance will deteriorate rapidly as the dimensionality of search space increases. In our ARW optimization model, we will adopt the CCPSO [14] algorithm to optimize the location of ARWs. The target of the ARW optimization model is to optimize the location of ARWs within a limited airspace. Following the previous work [9], the mathematical formulation of the ARW optimization problem has three assumptions and principles: (1) The ARN is defined as a planar graph, without considering aircrafts’ climbing or descending among different flight levels. (2) The trajectory of each flight is always the shortest path in the ARN. (3) Since the airport is a part of flight trajectory, we define the position of airports as one of the decision variables. An ARW is a navigation marker whose longitude and latitude coordinates are determined by the ground navaids. Thus, the location of airports and ARWs can be represented as 2-dimensional vectors, xmin i ≤xi≤xmax i , ∀i∈{1, ..., n}, ymin i ≤yi≤ymax i , ∀i∈{1, ..., n}, (1) where xi and yi represent the location of ARW i. Objective: The objective can be measured by the total flight conflict coefficient (TFCC). Here, the TFCC is a reference value indicating how “dangerous” the network is. Generally, the larger the total flight conflict is, the higher the flight conflicting risk is. min TFCC = ∑ ∑ ∑ fji∙fki∙S V∙cos ( αjk i 2 ) Ti k=1 Ti j=1 j≠k n i=1 , (2) where fji is the traffic flow from node j to node i, and fki is the traffic flow from node k to node i; ajk i ∈[0,π] is the included angle between air routes ji and ki; S is the horizontal separation standard (km) of air traffic control, and V is the average cruising speed (km/h) of flights. Constraint: The flight efficiency, which can be calculated by the total airline cost (TAC) of flights. min TAC = ∑ ∑ fij∙dij, m+n j=1 m+n i=1 (3)

Function Area Defining of Freeway Ramp

Scipedia content — Tue, 02 Feb 2021 06:45:31 +0100

Based on existing research and standards ,this paper proposed a new method of freeway ramp function area calculation, divided the ramp into upstream function area, downstream function area and ramp function area, and redefined each function area. Moreover, according to the relationship among vehicle speed of certain point, the time required to change lanes , design speed and other parameters,modified the time of a lane change in the "Traffic Engineering Handbook", proposed new equation of each area and figure out the length.

Study of Group Route Optimization for IoT Enabled Urban Transportation Network

Scipedia content — Tue, 02 Feb 2021 06:41:54 +0100

Traffic congestion is always a major issue in urban planning, especially when the vehicles in the roadway keep growing and the local authorities are lack of solutions to manage or distribute the traffics in the city. Although there are several factors that may cause traffic congestion, inefficiency in traffic management is always the main issue. Additionally, the most traditional methods of resolving traffic congestion or rerouting algorithm are mainly designed for individuals' benefits, by simply planning a driver's route based on minimum travel time or shortest path accordingly. There is lack of consideration in group benefit or urban development. However, with the development of technologies in Internet of Things (IoT), vehicle to vehicle (V2V) or Vehicle to Infrastructure (V2I) communications, group based routing becomes achievable. Instead of optimizing the routing path for individual drivers, this paper studies how to develop a new method to provide new routing method based on vehicles' similarities in a specific urban's transportation environment.

On caching with more users than files

Scipedia content — Tue, 02 Feb 2021 06:39:06 +0100

Caching appears to be an efficient way to reduce peak hour network traffic congestion by storing some content at the user's cache without knowledge of later demands. Recently, Maddah-Ali and Niesen proposed a two-phase, placement and delivery phase, coded caching strategy for centralized systems (where coordination among users is possible in the placement phase), and for decentralized systems. This paper investigates the same setup under the further assumption that the number of users is larger than the number of files. By using the same uncoded placement strategy of Maddah-Ali and Niesen, a novel coded delivery strategy is proposed to profit from the multicasting opportunities that arise because a file may be demanded by multiple users. The proposed delivery method is proved to be optimal under the constraint of uncoded placement for centralized systems with two files, moreover it is shown to outperform known caching strategies for both centralized and decentralized systems.

Comment: 6 pages, 3 figures, submitted to ISIT 2016

Create beautiful Highway Traffic Engineering Design

Scipedia content — Tue, 02 Feb 2021 06:35:44 +0100

Label encoding algorithm for MPLS Segment Routing

Scipedia content — Tue, 02 Feb 2021 06:34:03 +0100

International audience; Abstract: Segment Routing is a new architecture that leverages the source routing mechanism to enhance packet forwarding in networks. It is designed to operate over either an MPLS (SR-MPLS) or an IPv6 control plane. SR-MPLS encodes a path as a stack of labels inserted in the packet header by the ingress node. This overhead may violate the Maximum SID Depth (MSD), the equipment hardware limitation which indicates the maximum number of labels an ingress node can push onto the packet header. Currently, the MSD varies from 3 to 5 depending on the equipment manufacturer. Therefore, the MSD value considerably limits the number of paths that can be implemented with SR-MPLS, leading to an inefficient network resource utilization and possibly to congestion. We propose and analyze SR-LEA, an algorithm for an efficient path label encoding that takes advantage of the existing IGP shortest paths in the network. The output of SR-LEA is the minimum label stack to express SR-MPLS paths according to the MSD constraint. Therefore, SR-LEA substantially slackens the impact of MSD and restores the path diversity that MSD forbids in the network.

Line pilot perspectives on complexity of terminal instrument flight procedures

Scipedia content — Tue, 02 Feb 2021 06:17:02 +0100

Many new Performance Based Navigation (PBN) Instrument Flight Procedures (IFPs) are being developed as the United States transforms its airspace to improve safety and efficiency. Despite significant efforts to prepare for operational implementation of new IFPs, the process does not always go smoothly. The primary goal of this study was to understand what makes IFPs difficult from the perspective of line pilots. We spoke to 45 professional pilots in small groups. The pilots reviewed, briefed, and discussed six IFPs in an office setting. We extracted a comprehensive list of subjective complexity factors by observing pilot briefings and gathering pilot feedback. Then we organized the list into a framework that captures a variety of types of complexity. We define a subjective complexity factor as one that requires an extra mental or physical step by the pilot. IFP design parameters (e.g., the number of transitions and flight path constraints) are a main driver for subjective complexity for line pilots. Unusual IFP designs can result in novel chart depictions that are unfamiliar and more difficult to use. In turn, novel chart formats may have inconsistencies that increase subjective complexity. Participants also mentioned factors that are outside the control of IFP designers, such as weather, fatigue, and aircraft performance or equipment. We separate out these as operational complexity factors. The broad nature of the pilot interviews also provided insights into how pilots use charts today, in the context of the modern flight deck. A full report on the study is in preparation.

The Analysis and Optimization of the VANET Topology

Scipedia content — Tue, 02 Feb 2021 06:13:12 +0100

Keyword: VANET, Topology, Optimization, Adaptive Abstract: Vehicular Ad-hoc Networks (VANET) is the research focus of ad-hoc network technology in recent years. Due to fast-moving and other properties of Vehicles, it is extremely easy to change the Topology of the VANET, and communication channels of VANET may become unstable. Then the system performance of the VANET drop overall. Based on the VANET Topology features, this paper proposes an adaptive VANAET Topology optimized Method .According to it, all the region of the VANET is divided into several logical spaces adaptively. In logical region, the method make the connection of V2V or V2I more efficient as possible. and between logical regions, it select several key nodes as the center nodes connecting with other logical regions. So it not only can reduce the average Degree distribution a D in and between logical regions but also improve the connection efficiency  of the entire region. Thereby, providing professional traffic advices and emergency communication services for solving traffic congestion.

Discussion on urban road traffic congestion algorithm for automatically determining

Scipedia content — Tue, 02 Feb 2021 06:10:32 +0100

Compared with expressway, most of the traffic flow in urban road network can be denoted as interrupted traffic flow. Based on the currently employed equipment for traffic flow collection and traffic signal control in urban roads, different types of traffic flow in urban roads is analyzed with the traffic flow arrival/departure model in transportation engineering. Mathematical models complying with traffic flow changes are utilized to match the traffic flow in both entry and exit road blocks, thus enabling the automatic detection of traffic incident. This algorithm serves as a measure for the automatic judgment of urban road congestion and the expansion utility of intelligent transportation facilities in urban areas.

Off the Beaten Path: Let's Replace Term-Based Retrieval with k-NN Search

Scipedia content — Tue, 02 Feb 2021 06:02:39 +0100

Retrieval pipelines commonly rely on a term-based search to obtain candidate records, which are subsequently re-ranked. Some candidates are missed by this approach, e.g., due to a vocabulary mismatch. We address this issue by replacing the term-based search with a generic k-NN retrieval algorithm, where a similarity function can take into account subtle term associations. While an exact brute-force k-NN search using this similarity function is slow, we demonstrate that an approximate algorithm can be nearly two orders of magnitude faster at the expense of only a small loss in accuracy. A retrieval pipeline using an approximate k-NN search can be more effective and efficient than the term-based pipeline. This opens up new possibilities for designing effective retrieval pipelines. Our software (including data-generating code) and derivative data based on the Stack Overflow collection is available online.

Real-time performance and safety validation of an integrated vehicle dynamic control strategy

Scipedia content — Tue, 02 Feb 2021 06:00:50 +0100

The state of the art in automotive control has proposed several analytical, simulation and experimental studies of longitudinal adaptive cruise control strategies, and of lateral control strategies. However, methodical integration of these two strategies is to a large extent missing, as well as validation in real-time computing environment of the safety and performance of longitudinal and lateral integrated solutions. This work proposes a real-time validation of an integrated vehicle dynamic control strategy, designed to create safe interaction between longitudinal and lateral controllers: the integrated system is designed, implemented and tested through Dynacar, a real-time simulation environment for the development and validation of vehicle embedded functionalities. The results show that the proposed integrated controller satisfies the performance in terms of real-time computation, path tracking and collision avoidance for various driving situations.

Application of MPLS-TP for transporting power system protection data

Scipedia content — Tue, 02 Feb 2021 05:50:32 +0100

Power utilities are increasingly dependent on the use of communications networks. These networks are evolving to be packet-based, rather than using conventional Time-Division Multiplexing (TDM) technologies. Transporting current differential protection traffic over a packet network is especially challenging, due to the safety-critical nature of protection, the strict requirements for low delay and low asymmetrical delay, and the extensive use of legacy TDM-based protocols. This paper highlights the key technical characteristics of Multi-Protocol Label Switching-Transport Profile (MPLS-TP), and demonstrates its application for transporting current differential protection traffic. A real-time hardware-in-the-loop testing approach has been used to thoroughly validate the technologies in various configurations. It is demonstrated that MPLS-TP technologies can meet the requirements of current differential protection and other, less critical applications. In particular, it is shown that delay and asymmetrical delay can be controlled through the inherent use of bi-directional paths---even when “hitless” link redundancy is configured. The importance of appropriate traffic engineering, clocking schemes, circuit emulation methods is also demonstrated.

Wind optimal flight trajectories to minimise fuel consumption within a 3 dimensional flight network

Scipedia content — Tue, 02 Feb 2021 05:40:59 +0100

This paper assesses the potential fuel savings benefits that can be gained from wind optimal flight trajectories. This question is posed on a 3 dimensional fixed flight network consisting of discrete waypoints which is representative of the size of Europe. The optimisation implements Dijkstra's shortest path algorithm to compute the minimum fuel burn route through a network and compares this to the fuel burn for the shortest distance route. Particular effort is applied to testing the repeatability and robustness of the results. This is achieved through a sensitive analysis based on a number of identified model parameters relating to the setup of the flight network. The results of this study show fuel savings between 1.0%-10.3%, and suggest that the benefits of wind optimal flight trajectories are significant.

Evaluation metrics of upper extremities for people with neurological disorders: An energy based approach

Scipedia content — Tue, 02 Feb 2021 05:33:22 +0100

Various neurological disorders, like Parkinson's disease, Multiple Sclerosis, Huntington's disease and Stroke, affect millions of people worldwide. Tremor that is a result of these disorders affects the performance of many Activities of Daily Living such as dressing, bathing, self-care, and writing, which reduces the functional independence and self-rated quality of life. Standardized rating scales have been developed, however, these scales display some degree of variability due to their subjective/qualitative approach. Therefore, the accurate and objective measure of a patient's condition is crucial. Due to the lack of objectivity and accuracy from conventional procedures, there is a need to develop an objective evaluation system. In this work, a horizontal movement test is implemented in a Virtual Environment with the use of a Haptic Interface. The proposed test consists of a simple reaching task (more tasks are under development) for defining quantitative metrics. Wrist motion is accurately measured using the haptic interface and analyzed to calculate evaluation metrics based on the joint energy and spatial deviation from the ideal path. To improve the sensitivity of the metrics, a harmonic disturbance force is applied by the haptic interface to the user. The disturbance frequency is varied from 1 to 7 Hz and the duration of the movement is constraint to be constant. Fourteen healthy adults performed the experiments with 10 to 21 repetitions for each movement conditions. The results show that all users spend higher energy to complete the test at frequencies around 2.5 Hz. The statistical analysis indicates that energy is a reliable evaluation metric, with low variance, that can be used to quantify upper extremities. Copyright © 2017 ASME. 1

Modeling Functional Specifications of Ground Systems in the NAS

Scipedia content — Tue, 02 Feb 2021 05:30:58 +0100

The goal of the Airspace operations and Safety Program (AOSP) at NASA is to develop new concepts and technologies for air traffic management that can be integrated within the National Airspace (NAS ...

Scalable BGP Prefix Selection for Effective Inter-domain Traffic Engineering

Scipedia content — Tue, 02 Feb 2021 05:28:14 +0100

International audience; Inter-domain Traffic Engineering for multi-homed networks faces a scalability challenge, as the size of BGP routing table continue to grow. In this context, the choice of the best path must be made potentially for each destination prefix, requiring all available paths to be characterized (e.g., through measurements) and compared with each other.Fortunately, it is well-known that a few number of prefixes could carry a dominant part of the traffic. As a natural consequence, to engineer a majority of traffic only a handful of prefixes need to be managed. Yet, traffic characteristics of a given prefix can vary greatly over time, which requires us to predict most significant prefixes in the near future. Moreover, little is known on the traffic dynamism at this aggregation level and sophisticated prediction methods won’t scale in such context.In this paper, we study the relationship between prefix volume, stability, and predictability, based on recent traffic traces from nine different networks.Three simple and resource-efficient methods to se- lect the prefixes associated with the most important foreseeable traffic volume are then proposed. Such proposed methods are capable of select sets of prefixes with both excellent representativeness (volume cover- age) and stability in time, for which the best routes are identified. The analysis carried out confirms the potential benefits of a route decision engine.

Real-Time Probe Data Dashboards for Interstate Performance Monitoring During Winter Weather and Incidents

Scipedia content — Tue, 02 Feb 2021 05:27:12 +0100

The Indiana Department of Transportation (INDOT) manages over 1800 centerline miles of interstate that can be profoundly impacted by weather, crashes, and construction. Real-time performance measurement of interstate speeds is critical for successful traffic operations management. Agency managers and Traffic Management Center decision makers need situational awareness of the network and the ability to identify irregularities at a glance in order to manage resources and respond to media queries. One way to access this level of detail is crowdsourced probe vehicle data. Crowdsourced probe vehicle data can be obtained by collecting speed data from cell phones and global positioning system (GPS) devices. In Indiana, approximately 2673 predefined interstate segments are used to generate over 3.8 million speed records per day. These data can be overwhelming without efficient procedures to reduce and aggregate both spatially and temporally. This paper introduces a spatial and temporal aggregation model and an accompanying real-time dashboard to characterize the current and past congestion history of interstate roadways. The primary high level view of the aggregated data resembles a stock ticker and is called the “Congestion Ticker.” The data archive allows for after-action review of major events such as ice storms, major crashes, and construction work zones. The utility of this application is demonstrated with two case studies: a snowstorm that covered northern and central Indiana in February 2015 and an I-70 back of queue crash in April 2015.

Optimizing segment routing using evolutionary computation

Scipedia content — Tue, 02 Feb 2021 05:26:53 +0100

Segment Routing (SR) combines the simplicity of Link-State routing protocols with the flexibility of Multiprotocol Label Switching (MPLS). By decomposing forwarding paths into segments, identified by labels, SR improves Traffic Engineering (TE) and enables new solutions for the optimization of network resources utilization. This work proposes an Evolutionary Computation approach that enables Path Computation Element (PCE) or Software-defined Network (SDN) controllers to optimize label switching paths for congestion avoidance while using at the most three labels to configure each label switching path. This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT Fundac¸˜ao para a Ciˆencia e Tecnologia within the Project Scope: UID/CEC/00319/2013. info:eu-repo/semantics/publishedVersion

LISP-EC: Enhancing LISP with egress control

Scipedia content — Tue, 02 Feb 2021 05:23:34 +0100

International audience; The Locator/Identifier Separation Protocol (LISP) was specified a few years ago by the Internet Engineering Task Force (IETF) to enhance the Internet architecture with novel inbound control capabilities. Such capabilities are particularly needed for multihomed networks that dispose of multiple public IP routing locators for their IP networks, and that are willing to exploit them in a better way than what possible with the legacy Border Gateway Protocol (BGP) [8]. In this work, we specify how to enhance the LISP routing system to perform egress control too. Our goal is to give the highest possible routing optimization degree to LISP networks, so that ingress and egress traffic engineering strategies can be jointly performed, without requiring coordination between LISP and BGP. We design the enhancement to the LISP router system, specify the required protocol extensions, open sourcing the code and proving the overhead and the achievable gains by experimentation.

Analytical solutions for liquid slugs and PIGS traveling in pipelines with entrapped gas

Scipedia content — Tue, 02 Feb 2021 05:23:18 +0100

Liquid slugs have a relatively low mass and can therefore — when they occupy a full cross-section of a pipeline — be accelerated to very high velocities by means of pressurized gas. When entrapped gas pockets are present, pressures and temperatures may become dangerously high. Simple models and analytical solutions are derived and used to predict transient velocities, pressures and temperatures. The models have a generic character as they also describe the basics of breaking surface waves impacting on a wall, and pigs and bullets propelled by compressed gas.

DCRoute: Speeding up Inter-Datacenter Traffic Allocation while Guaranteeing Deadlines

Scipedia content — Tue, 02 Feb 2021 05:19:17 +0100

Datacenters provide the infrastructure for cloud computing services used by millions of users everyday. Many such services are distributed over multiple datacenters at geographically distant locations possibly in different continents. These datacenters are then connected through high speed WAN links over private or public networks. To perform data backups or data synchronization operations, many transfers take place over these networks that have to be completed before a deadline in order to provide necessary service guarantees to end users. Upon arrival of a transfer request, we would like the system to be able to decide whether such a request can be guaranteed successful delivery. If yes, it should provide us with transmission schedule in the shortest time possible. In addition, we would like to avoid packet reordering at the destination as it affects TCP performance. Previous work in this area either cannot guarantee that admitted transfers actually finish before the specified deadlines or use techniques that can result in packet reordering. In this paper, we propose DCRoute, a fast and efficient routing and traffic allocation technique that guarantees transfer completion before deadlines for admitted requests. It assigns each transfer a single path to avoid packet reordering. Through simulations, we show that DCRoute is at least 200 times faster than other traffic allocation techniques based on linear programming (LP) while admitting almost the same amount of traffic to the system.

Comment: 23rd IEEE International Conference on High Performance Computing (HiPC)

Document type: Conference object

Research on Improving Validity of Public Participation on Rail Transits

Scipedia content — Tue, 02 Feb 2021 05:13:41 +0100

The rail transit is playing an important role in solving ground traffic congestion, guiding urban space layout and improving effectiveness of land using. The public are paying more and more attention to its social influences and environmental problems in construction and operation stages. This paper analyses traits of rail transit's environmental impact and sums up the influencing factors in public participation by considering construction contents and environmental impact of the first project stage of Xi'an subway 5th line. Finally it draws the conclusion that whole-process public participation, diverse ways of information disclosure, more representative survey samples, more accurate and efficiency data statistic and valid public feedback can be the main ways for improving validity of public participation, lowing rail transit's environmental and social impact and enhancing the sustainable development of rail transit. Keywords-public participation; validity; rail transit; environmental impact assessment; whole-process I. INTRODUCTION

Connected Motorized Riders - A Smart Mobility System to Connect Two and Three-wheelers

Scipedia content — Tue, 02 Feb 2021 05:07:34 +0100

The Smart Cities Mission has been launched in India in 2015 to develop 100 cities, with smart mobility being one of the main topics in the mission. As urban areas are flooded with two (motorcycles) and three wheelers (auto-rickshaws), introducing smart control of such vehicles may reduce the congestions on the roads and the number of accidents. Indeed, over-speeding and drunken driving are common traffic violations. In this project we propose an IoT-based smart mobility system which tracks data, such as the vehicle location, vehicle speed, alcohol level of the driver, etc. efficiently over the internet. Our system has been conceived with CPAL, a high-level language meant to simulate and execute Cyber Physical Systems including IoT applications. A prototype running on ARM mbed IoT hardware, shows the feasibility of our concept. We believe that more efficient and interactive traffic management, more disciplined driving behaviors, reduction in accident rate, more controlled pollution, increased passenger safety can be achieved if systems like the one prototyped in this work deployed contributing to smarter cities.

Traffic Simulation of Hongqi Elevated Road in Yantai

Scipedia content — Tue, 02 Feb 2021 04:59:48 +0100

With the increasing number of vehicles in Yantai, the downtown traffic volume is increasing. Hongqi Road, the main road in Yantai exists the traffic congestion problems. Yantai Planning Bureau proposed to construct for viaduct this road. This design is mainly based on the planning and design of the elevated road in Yantai Hongqi Road (Hongqi Road intersection-Shanhai Road intersection). We used the VISSIM micro simulation system to carry out the simulation of the elevated road in Hongqi Road, and the stops and queue length are the evaluation indices for quantitative evaluation. Then through the evaluation indices and specific data obtained by simulation, we analyze the selection of the scheme and draw the final plan of the construction of the elevated road, which was provide a good reference for the planning and construction of Hongqi elevated road.

Evaluating an SH wave EMAT system for pipeline screening and extending into quantitative defect measurements

Scipedia content — Tue, 02 Feb 2021 04:58:21 +0100

Guided waves are now commonly used in industrial NDT for locating corrosion in pipelines in the form of wall thinning. Shear Horizontal waves generated by EMATs are used in a screening arrangement in this work to locate and size corrosion in terms of axial extent and circumferential positioning. This is facilitated by propagating SH waves circumferentially around the pipeline whilst moving a scanning rig axially, keeping transducer separation constant. This arrangement is preferential in that it can operate through thin(up to 1mm) coatings and does not require full access to the pipe’s circumference and is useful for detecting corrosion in difficult to access regions, such as below pipe supports and in subsea applications. The performance of the system in terms of screening capability and the possibilities of extension into more quantitative measures are assessed. The behaviour of different wave modes as they interact with defects is investigated via experimental measurements on artificially induced corro...

Error analysis of air traffic control command decision based on rough complex network

Scipedia content — Tue, 02 Feb 2021 04:55:56 +0100

Validating the FACTS2 air traffic simulation framework

Scipedia content — Tue, 02 Feb 2021 04:53:48 +0100

the heart of the modern air traffic management system there is the communication infrastructure that enables efficient aircraft guidance and safe separation in all phases of flight. However, although current systems are mature and generally providing a good service, they are suffering from the VHF band’s increasing saturation in high density areas. The EU and US, representing the two areas experiencing the most pressure, strive therefore for the sustainable modernization of the aeronautical communication infrastructure. Air traffic management communication shall transition from analog VHF voice communication to more spectrum efficient digital data communication supported by automated decisions of computer systems. This digitization of the air-ground communications infrastructure has to be evaluated carefully against the expected future air traffic to ascertain its sustainability and future-proofness. The accepted approach to this endeavor is to employ large-scale computer simulations. The most used method - generating synthetic air traffic with simplified flight trajectories from extrapolated flight plan databases - is largely accepted by the community as a good compromise between constant aircraft populations (too simplistic) and recorded real-world data (not available for the future). A combination of great-circle routes and simplified altitude profiles is deemed to provide sufficient fidelity for the simulation of long-range communication systems. However, the validity of this approach has yet to be investigated in detail. Although this investigation is certainly not possible in the general case we think that it can be performed for selected areas. In this paper we investigate the validity of synthetic air traffic generation for aeronautical communication system evaluation by comparing the results of our FACTS2 simulator to recorded flight data of Germany. FACTS2 is the German Aerospace Center's framework for aeronautical communication system evaluation.

INTEGRITY ASSESSMENT OF OFFSHORE AND ONSHORE OIL PIPELINES

Scipedia content — Tue, 02 Feb 2021 04:47:27 +0100

Impacts of geological store uncertainties on the design and operation of flexible CCS offshore pipeline infrastructure

Scipedia content — Tue, 02 Feb 2021 04:40:55 +0100

Planning for Carbon Capture and Storage (CCS) infrastructure needs to address the impact of store uncertainties and store flow variability on infrastructure costs and availability. Key geological storage properties (pressure, temperature, depth and permeability) can affect injectivity and lead to variations in CO2 flow, which feed back into the pipeline transportation system. In previous storage models, the interface between the reservoir performance and the transportation infrastructure is unclear and the models are unable to provide details for flow and pressure management within a transportation network in response to changes in the operation of storage sites. Variation in storage demand due to daily and seasonal variations of fossil fuels uses and by extension CO2 flow is also likely to influence transportation infrastructure availability and the capacity to deliver. This work evaluates, at the level of infrastructure planning, the impact of geological uncertainty on CCS pipeline transportation and injection infrastructure. The analysis presented shows how to consider uncertainty in store properties in combination with CO2 flow variability to estimate the likely impact on pipeline infrastructure design. The operational envelope of the storage site infrastructure is estimated by combining the Darcy flow analysis of simple reservoir models with rigorous process simulation of the storage site wells. The proximity of wellhead conditions to the CO2 equilibrium line and the maximum velocities inside the well constrain the operational envelope of the storage site and limit the ability of the storage site infrastructure to handle CO2 flow variation. These factors, which are significantly influenced by variations in subsurface conditions, have also an impact on the design of the offshore pipeline infrastructure, needing to accommodate changes in pressure delivery requirements. Based on the evaluation of examples developed for different offshore transportation scenarios relevant to the United Kingdom, detailed insight on the expected impacts of store properties on pipeline transportation infrastructure design and operation is provided. For instance, it is found that enabling storage site flexibility is simpler in stores with an initial pressure above 20MPa. Given reductions in reservoir permeability, the requirements for pressure delivery are strongly dependent on the store temperature. Although the analysis is performed for specific geological characteristics in the North Sea the evaluation methodology is transferable to other locations and can be used for site screening to identify sites which are more flexible in terms of uncertainty in store performance.

Document type: Article

Electric L-category vehicles for smart urban mobility

Scipedia content — Tue, 02 Feb 2021 04:40:31 +0100

The demand of personal mobility in European Union (EU) cities is increasing the use of motor vehicles; consequentially, gas emissions, noise levels and traffic jams increase, affecting quality of life of city-dwellers. To tackle such problems, European-wide emission targets are becoming stricter and urban mobility plans are being drawn. Future scenarios for EU urban centres see a modal shift in personal mobility from cars to lighter, smaller, more specialised and environmentally friendly alternatives. ELVs (Electric L-category Vehicles) are part of such alternatives that can cater to the average commuter's needs because of their small size and light weight; that means low on board energy requirement and small batteries, which allows lower costs and faster recharge. However, this modal shift offers new challenges: many urban users do not consider LVs as a viable and comfortable option for their needs. Urban policies could encourage ELV adoption, but four limiting factors are slowing down the diffusion of ELVs: cost, energy efficiency, attractiveness of ELVs and drivers willingness to use. RESOLVE EU project, co-funded under European Green Vehicles Initiative, is aimed at making ELVs practical alternatives to cars, by encouraging a number of commuters to switch to narrow-track ELVs. Led by the 2 largest LV manufacturers in EU and complemented by top component suppliers, Research Institutes and Universities, RESOLVE will give a contribution to reduction of overall urban traffic congestion, cutting commuting time and easing parking. To achieve its ambitious objectives, RESOLVE uses a holistic approach to explore solutions, culminating in two demonstration vehicles that will show the advances to the State-of-the-Art and could form a basis for attractive commercial ELV propositions. The project will start with user needs definition and market analysis, in order to ensure that expected technical results will be properly aimed. User needs will be identified taking into account the actual usage of either ICE (Internal Combustion Engine) powered-two-wheelers (PTWs) or light-heavy quadricycles (L6-L7 category) and of supermini (M1 category) cars in cities and suburban areas, throughout European countries. The task will also allow seeing which is the market potential size and share (shift from car drivers) by analysing database on market data and trends for ICE and electric L vehicles. User needs will be both quantitative data (e.g. km ridden per days, travel path, time stop, required performance etc.) and qualitative ones (such as parking easiness, manoeuvrability, acceptability by women/men, elderly/young, experienced/inexperienced, riders/drivers, protection from rain, etc.). Outcomes are the basis to develop a number of technological advances that aim to maximise the energy efficiency of ELVs, such as regenerative braking and lightweight design, as well as to optimise ELV rider experience, such as active vehicle stability and handling, human machine interface (HMI) and measures to enhance comfort and weather protection.

City-wide shared taxis: a simulation study in Berlin

Scipedia content — Tue, 02 Feb 2021 04:39:57 +0100

Recently, ridesharing services have grown rapidly. In future, fleets of shared and pooled autonomous vehicles may transform urban mobility. In this paper, we introduce an approach to dynamically simulate these services within a full-stack transport simulation using an insertion-based algorithm. In a first test case, using a taxi data set from Berlin, the potential for shared rides is evaluated using a fleet of vehicles with a capacity between two and four ride requests. The simulation suggests that the overall vehicle kilometers traveled may be reduced by 15-20%, while travel time increases can be kept at a relatively low level of less than three minutes per person. Additionally, the simulation results suggest in which areas of the city it may be the most rewarding to offer shared services.

Charging Electric Vehicles from Solar Energy

Scipedia content — Tue, 02 Feb 2021 04:27:45 +0100

Modelación en Transporte Público con Tren Ligero LRT en la Carrera 7, Bogotá, Colombia

Scipedia content — Tue, 02 Feb 2021 04:27:03 +0100

a contribution to solve mobility problems in Bogota, Colombia, this research applied computerized modeling techniques to study how to improve public transportation by implementation of an intended LRT system along the important Carrera 7 avenue, in consideration of its particular limiting conditions. Using specialized software, firstly, TransModeler simulated traffic flow conditions in the Carrera 7 sector between 34 and 53 streets, intersections included, to determine possible interferences of the light train operation; secondly, a particular train station concept, with elevated waiting platform, was conceptually designed and modelled in render format, adapted to the narrowest street section and minimum parallel traffic interferences. The Carrera 7 s main problems are a deficient public transportation service, and high traffic congestion and contamination, in limited physical space conditions, with failure on implementing the conventional TransMilenio, a BRT system. The study results showed a possible light train operation even in limiting space conditions and no need of private property acquisitions containing highly valued buildings, but with traffic interferences at intersections. Computerized modeling usefulness was realized, with recommendation to continue studies to solve train interference to normal vehicle traffic at intersections.

A branch-and-price algorithm for Dynamic Sector Configuration

Scipedia content — Tue, 02 Feb 2021 04:23:28 +0100

International audience; Air traffic generates workload for the air traffic controllers in charge of the airspace. For a large airspace, a single air traffic controller is not able to manage all this workload and the airspace is divided into sectors, each of them being assigned to a controller. When the traffic demand is decreasing during the night, the sectors are gathered together into groups to reduce the number of controllers in operation. Nowadays, this regrouping is performed empirically by airspace experts. In this paper, we show how the branch-and-price method can be used to compute a balanced grouping of air traffic control sectors to optimally reduce the number of controller teams during daily low flow periods.

A Systematic Assessment of Smartphone Usage Gaps

Scipedia content — Tue, 02 Feb 2021 04:09:00 +0100

Researchers who analyse smartphone usage logs often make the assumption that users who lock and unlock their phone for brief periods of time (e.g., less than a minute) are continuing the same "session" of interaction. However, this assumption is not empirically validated, and in fact different studies apply different arbitrary thresholds in their analysis. To validate this assumption, we conducted a field study where we collected user-labelled activity data through ESM and sensor logging. Our results indicate that for the majority of instances where users return to their smartphone, i.e., unlock their device, they in fact begin a new session as opposed to continuing a previous one. Our findings suggest that the commonly used approach of ignoring brief standby periods is not reliable, but optimisation is possible. We therefore propose various metrics related to usage sessions and evaluate various machine learning approaches to classify gaps in usage.

The selection of quantification pipelines for Illumina RNA-seq data using a subsampling approach

Scipedia content — Tue, 02 Feb 2021 04:05:12 +0100

RNA sequencing, or (RNA-seq for short,, is a widely applied technology that for extractings gene and transcript expression from biological samples. Given numerous quantification pipelines for RNA-seq data, one fundamental challenge is to determine identify a pipeline that can produce the most accurate estimate the most accurate gene and/or transcript expression. Exploring all available pipelines requires tremendous extensive computational resources, so. Therefore, we propose to use a subsampling approach that can improve speed up the pipeline evaluation and selection the efficiency process of pipeline performance evaluation for a given RNA-seq dataset. We applied our approach to one simulated and two real RNA-seq datasets and found that expression estimates derived from subsampled data are close surrogates for those derived from original data. In addition, the ranking of quantification pipelines based on the subsampled data was highly correlated concordant with that based on the original data. Therefore, we conclude that subsampling is a valid approach to facilitating efficient quantification pipeline selection using RNA-seq data.

Stop Sending Me Messages!: the Negative Impact of Persuasive Messages on Green Transportation

Scipedia content — Tue, 02 Feb 2021 03:51:09 +0100

Persuasive information and communication technology has been used to persuade people to choose fuelefficient transportation (i.e., green transportation), for example, by sending messages to the public. Many factors may influence the effect of such messages. In this exploratory we report a social experiment, in which participants received persuasive messages from social and non-social approaches. To our surprise, results seem to show a negative impact on green transportation, meaning participants receiving the messages used less green transportation modes. This suggests that messages may not be as an effective way to persuade the public as many organizations’ practice assumes and other persuasive techniques such as real-time feedback and awareness raising techniques may be needed in causing the desired changes.

Information Management for Smart and Sustainable Mobility

Scipedia content — Tue, 02 Feb 2021 03:41:01 +0100

The main objective of this work is to present a modular platform to manage traffic information for smart mobility. The management and collection of dynamic data is a challenging process especially in the context of low penetration of floating car data (FCD) and limited availability of traffic monitoring stations. In this work, three different road segments of a European medium-sized city were selected to collect vehicle dynamic data over multiple scenarios of traffic demand. Simultaneously, traffic volumes were recorded in real time. The main objective of this pilot experiment was to assess how it would be possible to read and predict traffic congestion and emissions levels with limited information and how data from multiple sources should be managed in order to correlate and deal with this information in real time. It was possible to correlate simultaneously multiple data set such as congestion values, specific vehicle power (VSP) mode distribution, Google traffic data and emission. Preliminary findings suggest that in urban arterials travel time and congestion levels can be reliable indicators for estimating emissions in real time. In sections of rural arterials, the estimation of real-time traffic performance is more complex. Key issues towards the implementation of a prototyping platform in an urban context are also discussed

The Influence of Traffic Structure on Airspace Capacity

Scipedia content — Tue, 02 Feb 2021 03:35:35 +0100

Best paper award for the Network Management track; International audience; Airspace structure can be used as a procedural mechanism for a priori separation and organization of en-route air traffic. Although many studies have explored novel structuring methods to increase en-route airspace capacity, the relationship between the level of structuring of traffic and airspace capacity is not well established. To better understand the influence of traffic structure on airspace capacity, in this research, four airspace concepts, representing discrete points along the dimension of structure, were compared using large-scale simulation experiments. By subjecting the concepts to multiple traffic demand scenarios, the structure-capacity relationship was inferred from the effect of traffic demand variations on safety, efficiency and stability metrics. These simulations were performed within the context of a future personal aerial transportation system, and considered both nominal and non-nominal conditions. Simulation results suggest that the structuring of traffic must take into account the expected traffic demand pattern to be beneficial in terms of capacity. Furthermore, for the heterogeneous, or uniformly distributed, traffic demand patterns considered in this work, a decentralized layered airspace concept, in which each altitude band limited horizontal travel to within a predefined heading range, led to the best balance of all the metrics considered.