Scipedia: Documents published in 2012

Variability of Pipe Coating Pull-Off Adhesion Measurements on Cylindrical Steel Pipelines

Scipedia content — Wed, 03 Feb 2021 18:12:03 +0100

One of the most commonly utilized, and stringent, quality assurance tests for coatings or linings on steel pipe is the destructive pull-off adhesion test according to ASTM D4541. The specified value of adhesion is generally in accordance with American Water Works Association (AWWA) C222 but for some projects adhesion values have been specified at very high levels which can be problematic from a testing or verification stand point. The rationale for high adhesion values (those greater than C222) appears to be a perception that very high adhesion values correlate to longer term corrosion protection. Usually, destructive pull-off tests are done by adhering metal "dollies" to the curved surface of the coated pipe using a fast reacting cyanoacrylate adhesive, and then mechanically pulling the dolly off in a radial direction. Tests are done not only on the very top of the pipe where it is possible to align the dollies well, but are also done around the sides of the pipe, where it is much more difficult to achieve ideal alignment of the dollies. Another limitation is that the adhesion of the glue to the coating may fail, giving a null result. Additionally, when the actual adhesion of coating is very high, the device for pulling the dollies from the pipe has a limit on the force that it can exert, and in necessity will terminate the test without giving a datum. The paper will discuss testing that was completed to examine the consistency of adhesion testing to ASTM D4541 on steel pipe coating with polyurethane applied in accordance with AWWA C222. Pipe diameter, flat surfaces, glue type (cyanoacrylate and epoxy), dolly diameter, polyurethane formulations scoring around dollies, and type of equipment were all considered in the testing. Possibilities for improving testing reliability and accuracy are discussed.

Development and Evaluation of a Steel-Composite Hybrid Composite Repair System

Scipedia content — Wed, 03 Feb 2021 17:58:55 +0100

Composite materials are widely recognized as a resource for repairing damaged pipelines. The fibers in conventional composite repair systems typically incorporate E-glass and carbon materials. To provide greater levels of reinforcement a system was developed that incorporates steel half shells and an E-glass composite repair system. In comparison with other competing composite technologies, the hybrid system has a significant capacity to reduce strain in corroded pipeline to a level that has not been seen previously. Specifically, the hybrid system was used to reinforce a pipe sample having 75% corrosion subjected to cyclic pressure at 36% SMYS. This sample cycled 767,816 times before a leak failure developed. Furthermore, recent testing has demonstrated that the hybrid system actually places the pipeline in compression during installation. This paper will provide results on a series of specifically-designed tests to evaluate the performance of the hybrid system and the implications in relation to the service of actual pipelines.Copyright © 2012 by ASME

Coordinated charging of electric vehicles

Scipedia content — Wed, 03 Feb 2021 17:45:10 +0100

Electric vehicles recharged from renewable energy sources will play an important role in reducing the key adverse impacts of transport: air pollution, depletion of oil resources, and CO2 emissions. But they will also add to the demand for electricity. Most electric vehicles will be charged at home, overnight. If they all charge at the same time, during the evening peak, they could cause the electricity supply of households or streets to become overloaded. Increases in peak demand ultimately require upgrades to the transmission and distribution infrastructure, which add significantly to the cost of electricity. An electric vehicle will typically need to charge for a few hours overnight. Coordinating the charging of electric vehicles distributed over many premises in an area can smooth the total demand in that area. In this paper we describe a simple load control system that uses signals broadcast from street transformers, typically servicing 30-50 premises, to influence the behaviour of smart appliances in the supplied premises to control the demand profile. Time-of-use tariffs can encourage users to shift their demand to times when electricity is cheaper because demand is usually lower. But to better manage the demand for electricity and control peak demand, we need appliances, including electric vehicles, that respond in real time to changing supply conditions by shifting their demand. Ultimately, having demand that can respond to the available supply will allow greater use of variable, renewable energy sources. Refereed/Peer-reviewed

Energy modelling of embedded multimedia streaming applications with GStreamer on heterogeneous MPSoC

Scipedia content — Wed, 03 Feb 2021 17:36:27 +0100

Embedded systems have to support more and more demanding multimedia applications. Heterogeneous multi-core architectures are now commonplace in mobile electronic devices. The impact on the power and energy consumption is tremendous; it has to be evaluated as soon as possible in the design process. Multimedia development frameworks are used to abstract the complexity of the hardware to the designer. In this paper, we propose a methodology to develop high-level performance and consumption models for multimedia streaming applications based on the GStreamer framework. Our approach is based on measurements of the power consumptions and execution times during the processing of combined video and audio streams. Performance and consumption models are build for various plugins instantiated in the corresponding GStreamer pipelines. The combination of estimations for all those plugins leads to a precise evaluation of the complete plugin performances. The precision of the models is evaluated against measurements for different real-life streaming applications.

Modeling Air Traffic Demand for a Real-Time Queuing Network Model of the National Airspace System

Scipedia content — Wed, 03 Feb 2021 17:34:39 +0100

predictive model for departure traffic demand and its route distribution at look-ahead times of 2-15 hours is proposed, for use in a queuing-network-based tool for strategic Traffic Flow Management (TFM). The proposed model uses a combination of operational data (filed flight plans, schedules), historical statistics of demand, and time- of-operation-specific factors to generate statistical predictions of traffic demand for particular routes between pairs of airports or airport clusters. Specifically, a two-stage predictor for demand is proposed. First, traffic demand for an origin-destination (O-D) pair is modeled as the summation of a known demand which captures filed and scheduled traffic, and an unknown demand which is modeled as non-homogeneous Poisson process. Second, the fraction of this O-D traffic demand on each route is modeled using a linear regression, with the historical route fractions, known (filed) route fractions, and wind-adjusted transit times for the routes serving as regressors. Historical data on demands and actual traffic volumes are used to evaluate aspects of the model, including the Poisson-process assumption and the regression model for route distributions.

Stuck in Traffic (SiT) Attacks: A Framework for Identifying Stealthy Attacks That Cause Traffic Congestion

Scipedia content — Wed, 03 Feb 2021 17:29:12 +0100

Recent advances in wireless technologies have enabled many new applications in Intelligent Transportation Systems (ITS) such as collision avoidance, cooperative driving, congestion avoidance, and traffic optimization. Due to the vulnerable nature of wireless communication against interference and intentional jamming, ITS face new challenges to ensure the reliability and the safety of the overall system. In this paper, we expose a class of stealthy attacks -- Stuck in Traffic (SiT) attacks -- that aim to cause congestion by exploiting how drivers make decisions based on smart traffic signs. An attacker mounting a SiT attack solves a Markov Decision Process problem to find optimal/suboptimal attack policies in which he/she interferes with a well-chosen subset of signals that are based on the state of the system. We apply Approximate Policy Iteration (API) algorithms to derive potent attack policies. We evaluate their performance on a number of systems and compare them to other attack policies including random, myopic and DoS attack policies. The generated policies, albeit suboptimal, are shown to significantly outperform other attack policies as they maximize the expected cumulative reward from the standpoint of the attacker.

Signal Separation for Transient Wave Reflections in Single Pipelines Using Inverse Filters

Scipedia content — Wed, 03 Feb 2021 17:22:43 +0100

Achieving Dependability Value for Pipelines and Facilities

Scipedia content — Wed, 03 Feb 2021 17:07:27 +0100

In today’s competitive and changing environment, it is crucial that pipelines and associated facilities create and sustain value for their stakeholders. This value can only be achieved by incorporating dependability into the pipeline system, in whole or in part. Dependability characteristics address not just availability and reliability as the probability of successful performance, but also identify other potential risk exposures such as degradation and wear-out that advocate the need for maintenance and logistic support to sustain “problem free” pipeline and facility operation. Dependability engineering provides practical means and measurable targets for achieving value, which are then implemented by sound operational risk assessment practices. Dependability management is needed to present viable business success options on risk avoidance, prevention, and mitigation; and where applicable, provides cost-effective risk treatments to support pipeline operation and enhance facility management. Characterizing the value of dependability focuses on two key issues: (1) what is the value of dependability, and (2) what is required to achieve it. This paper establishes a unified approach for understanding the dependability principles and practices, and enunciates how dependability value can be ascertained and assured in real life situations. It presents a general framework and provides implementation guidelines for ensuring that dependability value can be achieved in practical application for pipelines and facilities.Copyright © 2012 by ASME

In-vehicle speaker recognition using independent vector analysis

Scipedia content — Wed, 03 Feb 2021 16:59:39 +0100

part of human-centered driver assist framework for holistic multimodal sensing, we present an evaluation of independent vector analysis for speaker recognition task inside an automotive vehicle. Independent component analysis-based blind source separation algorithms have attracted attentions in recent years in the application of speech separation and enhancement. Compared to the traditional beamforming technique, the blind source separation method may typically require less number of microphones and perform better under reverberant environment. We recorded two speakers in the driver and front-passenger seats talking simultaneously inside a car and used independent vector analysis to separate the two speech signals. In the speaker recognition task, we show that by training the model with the speech signals from the IVA process, our system is able to achieve 95 % accuracy from a 1-second speech segment.

An Initial Assessment of Benefits for Noise-Aware Decision-Support Tools

Scipedia content — Wed, 03 Feb 2021 16:54:40 +0100

current trend in Air Traffic Management research is the development of decision support tools to aid in the sequencing and scheduling of terminal area and en route traffic as a means of increasing overall capacity and efficiency of operation. What is emerging as an increasingly important factor for terminal operations, however, is the environmental impact – in particular that of noise exposure. Thus, “noise-aware” decision support tools are needed so that the decision process includes consideration of noise exposure levels, particularly for the population within the immediate vicinity of the airport. This paper describes two elements of our on-going work in this direction. We first present results from simulation of the effects of noise-aware decision support tools at four U.S. airports having drastically different features and constraints. These results indicate the potential for noise-aware decision support tools to significantly improve noise exposure profiles. We also discuss the means by which a newly developed noise-aware decision support tool, the Noise Avoidance Planner, is incorporating a noise figure of merit into real-time, dynamic determination of sequencing and routing information. This work complements the simulation study, and provides additional indications of the benefits of including noiseawareness in terminal area decision support tools.

On the use of Trial and Error Traffic Engineering techniques in the Internet

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

The Border Gateway Protocol governs the overall routing in the Internet. With the time, it has been overloaded with functions which is was not initially designed for. The main example is Traffic Engineering. Internet Service Providers need to adjust the traffic on their peerings and in absence of a better alternative, use Trial and Error techniques based on manipulating the Autonomous System Path attribute in Border Gateway Protocol (BGP-4) updates. This paper shows sequences of BGP-4 updates where the use of Trial and Error Traffic Engineering techniques have led to instability and the countermeasures used to minimise their impact impact. The analysis methods presented also partially reveal the way Internet Service Providers use AS_PATH Prepending.

Do electric cars have to make noise? An emblematic opportunity for designing sounds and soundscapes

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

International audience; Electric cars tend to become the emerging generation of automotive vehicles for the next decades. One of their main features is that they are rather silent and then present issues as: must electric cars be sonified for preventing pedestrians from dangers? If necessary, what kind of sound signal is to be put to fulfill safety rules without contributing to the environmental pollution ? Moreover, because the starting point of this thought is nearly a blank page, it opens a large field of experimentation on different aspects of sound design: innovative approaches to create sounds in interactive configurations, role of sound to convey functional informations, aesthetics qualities or even emotional feelings, etc. In the frame of an industrial collaboration, we tried to handle these questions by examining the state-of-the-art in that domain, defining the specifications that sound has to comply with (warning for direction and speed, driver feedback of speed and functionning, various branding components, etc.), prototyping various ideas of interactive sonification, and initiating evaluation experiments especially in terms of primary functions (notification of presence and approaching speed). Some results from different steps of this work together with overall reflections and perspectives on the general topic will be presented and discussed.

Capturing Desired Attributes of a Dynamic Airspace Design Method

Scipedia content — Wed, 03 Feb 2021 16:23:37 +0100

From 2007 to 2010, six airspace design methods were developed by NASA with the goal of dynamically changing sector boundaries to reduce imbalances between air traffic demand and control capacity. These airspace design methods were evaluated in either or both fasttime and human-in-the-loop air traffic simulations. Whereas all of the six airspace design methods share a common goal ‐ to reduce demand and capacity imbalances by redrawing sector boundaries ‐ each method uses a different approach to achieve this goal. The objective of this paper is to capture desired attributes of a dynamic airspace design method. That is, using the previous simulations’ data, identify attributes from the six methods that increase air traffic system benefit and generate airspace designs that are acceptable to air traffic controllers. The intent of this paper is not to specify a particular airspace design method. Rather, the intent is to compile a list of desired attributes of a consolidated airspace design method that may be implemented in the future for further evaluation and development. Results show that the system benefit and the controller acceptance level of redrawn airspace boundaries increased most with attributes that enhanced the output sectors’ alignment to the direction of traffic flow. They are clean-sheet followed by localimprovement redrawing approach, aircraft count and sector design cost function base, and modified topology from the input airspace. Another attribute, implicit output sector number specification, increased the system benefit when compared to explicit specification.

A predictive aircraft landing speed model using neural network

Scipedia content — Wed, 03 Feb 2021 16:22:00 +0100

Expected increases in air traffic demand have stimulated the development of automated tools intended to assist the air traffic controller in accurately and precisely spacing aircraft landing at congested airports. Such tools require an accurate landing-speed prediction to increase throughput while decreasing the need for controller' interventions for avoiding separation violations. There are many practical challenges to developing an accurate landing-speed model that has acceptable prediction errors. This paper focuses on a near-term implementation, using readily available information, to model the final approach speed profile from the top-of-descent phase of flight to the landing runway. The developed models accurately predicted the landing speed, for the MD-80 aircraft type operations at the Dallas/Fort Worth airport, 95% of times with error margins of 12.6% for the low-and-no gust and 12% for high gust conditions, respectively. Also, the models reduced the uncertainties of the landing speed predictions by at least 9.5% for both gust conditions from the current state-of-the-art predictions.

Online Learning for Ground Trajectory Prediction

Scipedia content — Wed, 03 Feb 2021 16:11:20 +0100

This paper presents a model based on an hybrid system to numerically simulate the climbing phase of an aircraft. This model is then used within a trajectory prediction tool. Finally, the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) optimization algorithm is used to tune five selected parameters, and thus improve the accuracy of the model. Incorporated within a trajectory prediction tool, this model can be used to derive the order of magnitude of the prediction error over time, and thus the domain of validity of the trajectory prediction. A first validation experiment of the proposed model is based on the errors along time for a one-time trajectory prediction at the take off of the flight with respect to the default values of the theoretical BADA model. This experiment, assuming complete information, also shows the limit of the model. A second experiment part presents an on-line trajectory prediction, in which the prediction is continuously updated based on the current aircraft position. This approach raises several issues, for which improvements of the basic model are proposed, and the resulting trajectory prediction tool shows statistically significantly more accurate results than those of the default model.

Comment: SESAR 2nd Innovation Days (2012)

Consideration of Strategic Airspace Constraints for Dynamic Weather Routes

Scipedia content — Wed, 03 Feb 2021 16:08:18 +0100

This paper describes analysis of strategic airspace constraints related to flights selected for dynamic weather routes. Dynamic weather routes slightly modify a flight’s currently active flight plan. They are applied from the aircraft’s current location to a flight plan fix downstream, while avoiding forecasted convective weather regions using up to two additional waypoints. Air traffic congested sectors and Special Use Airspaces are the two types of airspace constraints that are considered in this study. The sector traffic counts are predicted to avoid congestion downstream along the dynamic weather routes. A comparison of congested sectors for actual tracks flown and aircraft simulated to fly on dynamic weather routes is shown using five days of data from the Fort Worth Center. Also, a qualitative measure of goodness of the dynamic weather route is presented. This score indicates the difference of flying the actual tracks versus flying the dynamic weather route from a sector congestion point of view. Current analysis indicates that proposing dynamic weather routes helps save time, and consequently fuel, and alleviates congestion overall. For the cases considered, it also appears that the suggested routes could route aircraft away from congestion, helping traffic managers take aircraft away from congested areas. The dynamic weather route suggestions are also evaluated for traversal through Special Use Airspaces. The Special Use Airspace impact is presented as an advisory for selection of the routes by aircraft operators.

Parametrized Verification of Distributed Cyber-Physical Systems: An Aircraft Landing Protocol Case Study

Scipedia content — Wed, 03 Feb 2021 16:05:48 +0100

In this paper, we present the formal modeling and automatic parameterized verification of a distributed air traffic control protocol called the Small Aircraft Transportation System (SATS). Each aircraft is modeled as a timed automaton with (possibly unbounded) counters. SATS is then described as the composition of N such aircraft, where N is a parameter from the natural numbers. We verify several safety properties for arbitrary N, the most important of which is separation assurance, which ensures that no two aircraft may ever collide. The verification methodology relies on computing the set of backward reachable states from the set of unsafe states to a fixed point, and checking emptiness of the intersection of these reachable states and the initial set of states. We used the Model Checker Modulo Theories (MCMT) tool, which implements this technique.

Moby.Cockpit Project for EV seamless integration in the cooperative transport infrastructure

Scipedia content — Wed, 03 Feb 2021 15:49:47 +0100

Electric Vehicles (EV) are being introduced in the market, however the reduced energy storage capacity of their batteries and the lack of a high density charging infrastructure, limits their autonomy range. In order to overcome this limitation, we propose the development of a new solution for EV drivers that enables to travel longer distances. This is achieved by integrating some components of the cooperative transport infrastructure, as EV battery charging systems and public transports systems, and by increasing the driving autonomy through energy consumption reduction, achieved by driving efficiency increase. The integration with the charging infrastructure allows planning the journey of the driver, considering the position of charging points, and booking a charging point for a specific time period in order to perform the battery charging. Therefore, the distance that the driver can drive comfortably, without fearing running out of battery, is increased. The integration of the EV with public transports systems allows extending the travel distance beyond the EV drive autonomy, given by the storing capacity of vehicle’s battery. The supplying of information on availability, schedule and price of public transports allows planning the journey of the driver, using the EV and public transportation in a complementary way, through functions like car parking booking (and charging) and ticket buying. Fundação para a Ciência e a Tecnologia (FCT)

High Definition Electrical Capacitance Tomography for Pipeline Inspection

Scipedia content — Wed, 03 Feb 2021 15:35:17 +0100

Pipelines made of dielectric materials such as Polyethylene (PE) are becoming increasingly popular. With no suitable inspection technique for dielectric pipes, there is an urgent need to develop new technology for their inspection. This paper presents a novel pipe inspection technique using Electrical Capacitance Tomography (ECT) imaging. Traditionally ECT is used for industrial process tomography as a low resolution but fast tomographic imaging technique. Typically commercial ECT can provide a resolution of approximately 10 percent of the imaging region. In this paper a limited region tomography technique is developed take into account prior knowledge about the geometry of the pipe. This has signiflcantly enhanced the imaging resolution of the ECT system, making it a viable pipe inspection solution. The experimental results in this study demonstrate an interior wall loss area as small as 0.195 percent of the ECT cross sectional imaging region is repeatable and can be reliably detected. A narrowband pass fllter method (NPFM) is used as a means to limit the region for the ECT algorithm. This results in an unprecedented resolution, making ECT a viable non-destructive evaluation (NDE) technique for plastic pipes. The NDE application of the ECT for PE pipes is demonstrated in this paper with several experimental results. A wall loss of depth of 1.5mm could be detected for an ECT sensor array of 150mm in diameter, showing a high resolution and high deflnition ECT (HD-ECT) imaging that has not been reported before.

Development of Ultrasonic Phased Array Inspection of Polyethylene Pipe Joints

Scipedia content — Tue, 02 Feb 2021 08:46:34 +0100

The current practice for assuring the quality of butt fusion joints in polyethylene (PE) pipes during installation is by recording the welding parameters used, together with a visual inspection of the welded joint, supplemented by the destructive testing of welds on a sample basis using a short-term test. However, visual inspection can only examine the external surface of the pipe weld; it cannot provide evidence of embedded flaws or a weld with incomplete fusion or cold fusion. In addition, cutting a specimen from a weld for mechanical testing and then replacing it with a weld of unknown quality does not ensure the integrity of the pipeline. Volumetric non-destructive examination (NDE) will not destroy perfectly good welds and has the added environmental advantage of reduced waste."/jats:p" "jats:p"This paper describes an ongoing European-funded project to develop ultrasonic phased array techniques for the inspection of butt fusion (BF) and electrofusion (EF) joints in PE pipes of diameters between 90 and 1000mm, and to determine critical defect sizes and particulate contamination levels using accelerated long-term testing. In addition, defect recognition and automated defect sentencing software will be developed to allow the system to automatically sentence detected flaws.

Towards a post-fossil urban transport system: an actor-oriented approach

Scipedia content — Tue, 02 Feb 2021 08:38:16 +0100

Mobility in urban areas offers a huge potential to decouple transport from fossil fuels. Energy efficiency and fuel diversification are key. Many policies and measures towards post-fossil transport are available, but information on implementation responsibilities is insufficient. The present paper goes beyond the definition of suitable policies and measures, but identifies key actors in transforming urban transport towards less oil dependency. It is analysed how each key actor can contribute to a post-fossil fuel transport system and their role in the development and realisation of policies and measures is defined. To describe the effects of each actor’s activities, policies and measures are allocated to the four different components of a post-fossil transport system: system efficiency, travel efficiency, vehicle efficiency and alternative fuels. This process uncovers main actors for each building block of a sustainable transport system. The analysis shows that responsibilities for post-fossil transport are spread among different municipal departments and national ministries. Instruments to reduce the travel activity or to increase the share of energy-efficient modes are mainly in the responsibility of local authorities, whereas instruments to improve vehicle fuel economy and to introduce alternative fuels are in the hand of national ministries. Furthermore, many policies and measures need interdepartmental or interministerial support for successful implementation. Close cooperation between key actors is necessary to steer urban transport towards less fossil-fuel dependency.

Comparison of charging systems for electric vehicles and their impact on electrical grid

Scipedia content — Tue, 02 Feb 2021 08:35:30 +0100

This paper presents a comparison of four types of on-board batteries charging systems for Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs), and their impact on the power quality of the electrical power grid. In the comparison are analyzed the features, the characteristics and the operation of each charging system, aiming their controllability and their impact on the electrical grid, mainly considering the Total Harmonic Distortion (THD) of the consumed current and the power factor. Besides the normal mode of operation to charge the batteries, denominated Grid-to-Vehicle (G2V), in this paper is also discussed the possibility of operation as Vehicle-to-Grid (V2G), in which the batteries of the Electric Vehicle return part of the stored energy back to the electrical grid. The operation of the batteries charging systems for EVs is shown through simulations and experimental results. FEDER Funds - Operational Programme for Competitiveness Factors (COMPETE) Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EEA-EEL/104569/2008, MITPT/EDAM-SMS/0030/2008

Tehran traffic congestion charging management: a success story

Scipedia content — Tue, 02 Feb 2021 08:34:58 +0100

A multi-Vdd dynamic variable-pipeline on-chip router for CMPs

Scipedia content — Tue, 02 Feb 2021 08:34:01 +0100

We propose a multi-voltage (multi-Vdd) variable pipeline router to reduce the power consumption of Network-on-Chips (NoCs) designed for chip multi-processors (CMPs). Our multi-Vdd variable pipeline router adjusts its pipeline depth (i.e., communication latency) and supply voltage level in response to the applied workload. Unlike dynamic voltage and frequency scaling (DVFS) routers, the operating frequency is the same for all routers throughout the CMP; thus, there is no need to synchronize neighboring routers working at different frequencies. In this paper, we implemented the multi-Vdd variable pipeline router, which selects two supply voltage levels and pipeline modes, using a 65nm CMOS process and evaluated it using a full-system CMP simulator. Evaluation results show that although the application performance degraded by 1.0% to 2.1%, the standby power of NoCs reduced by 10.4% to 44.4%.

Scalable and Efficient Associative Processor Solution to Guarantee Real-Time Requirements for Air Traffic Control Systems

Scipedia content — Tue, 02 Feb 2021 08:33:06 +0100

This paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machine model called an Associative Processor (AP). Our solution differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the predictability requirements for ATC, which are critical for meeting the strict certification standards required for safety critical software components. The proposed AP solution supports accurate predictions of worst case execution times and guarantees all deadlines are met. Furthermore, the software developed based on the AP model is much simpler and smaller in size than the current corresponding ATC software. As the associative processor is built from SIMD hardware, it is considerably cheaper and simpler than the MIMD hardware currently used to support ATC. We have designed a prototype for eight ATC real-time tasks on Clear Speed CSX600 accelerator that is used to emulate AP. Performance is evaluated in terms of execution time and predictability and is compared to the fastest host-only version implemented using OpenMP on an 8-core multiprocessor (MIMD). Our extensive experiments show that the AP implementation meets all deadlines that can be statically scheduled. To the contrary, some tasks miss their deadlines when implemented on MIMD. It is shown that the proposed AP solution will support accurate and meaningful predictions of worst case execution times and will guarantee that all deadlines are met.

Field testing of a low-cost, self-referenced all-fibre polarimetric current sensor for the monitoring of current in the high-speed railway catenary

Scipedia content — Tue, 02 Feb 2021 08:12:59 +0100

Optical Sensing and Detection II, Brussels, Belgium , 16-19 April, 2012 In this paper we present the field testing results of a low-cost all-fibre polarimetric current sensor for the monitoring of current in the European high-speed railway network. The sensor fulfils the requirements of robustness, sensitivity, accuracy and cost required for the monitoring of catenary current in changeover sections. Changeover sections are nonfed sections of the catenary that are placed between sections fed with different phases and that introduce discontinuities in the current collection done by the train. Since the train passes at high-speed between the two sections, an electric arc can be formed that may lead to significant damage of the infrastructure. To avoid this situation, it is essential to ensure the switch-off of the current collection before arriving and switch-on again when the changeover section is passed. An adequate protection system that monitors the current in the catenary before the changeover section allows to trigger the necessary protection mechanisms in the infrastructure. Efficient, robust and lightweight electrical current sensors are therefore essential for this security system. The sensor proposed here uses the Faraday magneto-optic Effect with a well-known polarimetric interrogation method. The optical configuration is extremely simplified through the use of few cost-effective, all-fibre devices with a simplified alignment. It allows high sensitivity for low current values, demonstrating a resolution below the ampere level with a dynamic range up to 500 A. The setup is electronically self-referenced to reduce the effect of small misalignments in the polarization, power variations in the optical source, temperature changes, birefringence effect and bending-induced attenuation in the lead fibre. A set of temperature tests in a climatic chamber were also performed in a range of temperature between -20 up to 80°C, to assess the robustness of the device to operating temperature variations. The field tests include tests during commercial operations and special tests simulating fault conditions.

Visual Analysis of Air Traffic Data Using Aircraft Density and Conflict Probability

Scipedia content — Tue, 02 Feb 2021 08:12:06 +0100

This paper presents visual analysis tools intended to aid researchers and policy makers by producing a visual representation of air traffic density and, by taking into account the required aircraft separation minima, the conflict probability. The tools support visualization of time-varying air traffic density over an area of interest using different time granularity. This visual analysis platform is used to investigate how potential changes to the aircraft separation policy can reduce congestion while maintaining key safety requirements. The same platform can also be used as a decision aid when assessing potential flight plans for unmanned aerial vehicles.

Un modèle en programmation entière pour le transport aérien de produits dangereux et spéciaux

Scipedia content — Tue, 02 Feb 2021 08:09:11 +0100

The aircraft loading problem is a real-world combinatorial optimisation problem highly constrained. This weight must be distributed to keep the centre of gravity within speci ed limits. Moreover, an aircraft has usually several cargo compart- ments with speci c contours and structural limitations such as oor loading, com- bined load limits and cumulative load limitations. Finally, some shipments are par- ticularly restrictive to transport, like dangerous goods, live animals and perishable goods. This paper is concerned with the incorporation of these latter constraints in a mixed integer linear program for the problem of loading a set of Unit Load- ing Devices and bulk into an aircraft. Experimental results show that our method achieves optimal solutions within only few seconds. Peer reviewed

Automated pipeline extraction for modeling from laserscanned data

Scipedia content — Tue, 02 Feb 2021 08:03:55 +0100

Purpose Threedimensional (3D) as-built plant models are required for various purposes, such as plant operation, maintenance, and the expansion of existing facilities. The as-built plant model reconstruction process consists of as-built plant measurement and 3D plant model reconstruction. As-built plant measurement uses 3D laser scanning technology to efficiently acquire data. However, the current method used for 3D as-built plant model reconstruction from laserscanned data is still labor-intensive. The objective of this study is to develop a fully-automated parametric reconstruction of the as-built pipe-line occupying a large portion of the area in an as-built plant. Method The proposed approach consists of three main steps. The first step is to extract the cylindricallyformed pipelines from laser-scanned data based on random sampling consensus (RANSAC). The second step is to segment the extracted pipelines into pipe components, such as straight pipe, elbow, and branch tee, based on medial axis extraction and curve skeletonization. The last step is to surface-model reconstruct the segmented pipe-lines using the parametric modeling method. Results & Discussion The experiment was performed at an operating plant to validate the proposed method. The experimental results revealed that the proposed method could contribute to automation for 3D as-built plant model reconstruction.

Underwater pipeline and cable inspection using autonomous underwater vehicles

Scipedia content — Tue, 02 Feb 2021 07:59:41 +0100

To ensure their continuing integrity, the state of pipelines and cables needs to be monitored regularly. Divers, towfish ore remotely operated underwater vehicles (ROVs), which are traditionally used for cable & pipeline inspection, are time and human resources intensive. On the other hand, autonomous underwater vehicles (AUVs) represent a tool with great benefits. Therefore, a reliable localization and robust tracking system is required and it is the focus of this paper. The developed system will be tested for its performance in different pipeline layout scenarios.

Towards video processing in vehicles under adverse weather conditions

Scipedia content — Tue, 02 Feb 2021 07:54:48 +0100

In this contribution we propose methods for vehicle detection and tracking for the Advanced Driver Assistance Systems (ADAS) that work under extremely adverse weather conditions. Most of the state-of-the-art vehicle detection and tracking methods are based either on appearance based vehicle recognition or on extraction and tracking of dedicated image key points. Visibility deterioration due to rain drops and water streaks on the windshield, swirling spray, and fog lead to a drastic performance reduction or even to a complete failure of these approaches. In this contribution we propose several methods for coping with these phenomena. In addition to an extension of the feature-based tracking method, which copes with outliers and temporarily disappearing key points, we present a detection and tracking method based on search for vehicle rear lights and whole rear views in the saturation channel. Utilization of symmetry operators and search space restriction allows to detect and track vehicles even in pouring rain conditions. Furthermore, we present two applications of the above-described methods. Estimation of the strength of spray produced by preceding vehicles allows to draw conclusions about the overall visibility conditions and to adjust the intensity of one's own rear lights. Besides, a restoration of deteriorated image regions becomes possible.

DAARIA: Driver assistance by augmented reality for intelligent automobile

Scipedia content — Tue, 02 Feb 2021 07:51:00 +0100

International audience; Taking into account the drivers' state is a major challenge for designing new advanced driver assistance systems. In this paper we present a driver assistance system strongly coupled to the user. DAARIA 1 stands for Driver Assistance by Augmented Reality for Intelligent Automobile. It is an augmented reality interface powered by several sensors. The detection has two goals: one is the position of obstacles and the quantification of the danger represented by them. The other is the driver's behavior. A suitable visualization metaphor allows the driver to perceive at any time the location of the relevant hazards while keeping his eyes on the road. First results show that our method could be applied to a vehicle but also to aerospace, fluvial or maritime navigation.

Accurate distance estimation using camera orientation compensation technique for vehicle driver assistance system

Scipedia content — Tue, 02 Feb 2021 07:41:04 +0100

This paper proposes a camera orientation compensation technique to help compensating unwanted camera orientation so as to accurately estimate the distance of a preceding vehicle in a vehicle driver assistance system. We propose a method in computing a homography to compensate the unwanted camera orientation misalignment. Distance between the preceding vehicle and the digital camera can then be accurately estimated. We will demonstrate that this approach be most suitable for vehicle driver assistance systems, and it also further expands the extent of automobile safety.

Evaluation of the Convective Weather Avoidance Model for Arrival Traffic

Scipedia content — Tue, 02 Feb 2021 07:32:20 +0100

The effective management of traffic flows during convective weather events in congested air space requires decision support tools that can translate weather information into anticipated air traffic operational impact. In recent years, MIT Lincoln Laboratory has been maturing the Convective Weather Avoidance Model (CWAM) to correlate pilot behavior in the enroute airspace with observable weather parameters from convective weather forecast systems. This paper evaluates the adaptation of the CWAM to terminal airspace with a focus on arrival decision making. The model is trained on data from five days of terminal convective weather impacts. The performance of the model is evaluated on an independent dataset consisting of six days of convective weather over a variety of terminal areas. Model performance in different terminal areas is discussed and the sensitivity of prediction accuracy to weather forecast horizon is presented. I. Introduction future air traffic system capable of predicting convective weather impacts and proactively issuing TMIs will more effectively use the available airspace, and in turn mitigate the effect of convective weather on the system. The Convective Weather Avoidance Model (CWAM) is a probabilistic model of pilot decision making in the presence of convective weather. CWAM is based on the correlation of spatially filtered weather observations with trajectories of aircraft that penetrated or avoided areas of convective weather in the en route flight regime [1]. The output of the en route CWAM is a three-dimensional {cloud tops, flight altitude, precipitation intensity} Weather Avoidance Field (WAF) that provides the likelihood that a pilot will deviate at a specific position and time given the current and forecasted weather. Outside of the en route phase (e.g. during departure and arrival), aircraft are commonly below the tops of most convection and are subject to different decision mechanisms, both of which are not modeled in the original CWAM. Therefore, in order to model impacts over an entire flight trajectory, CWAM should be adapted to include low-altitude flight phases such as arrival and departure [2]. This paper presents an evaluation of the adaptation of CWAM for arrival operations. Arrival CWAM is trained on approximately 11,000 flights and 1,900 terminal weather encounters over five convective weather days [3]. The training database includes multiple types of weather avoidance decisions that occur during arrival operations to four major metroplex areas (ORD, DFW, CLT, DEN). The decisions types distinguish between strategic and tactical time horizons and encompass both pilot and air traffic management decisions. Additionally, unlike pilots in en route airspace who may have an option to fly at higher altitudes over storms, pilots in arrival airspace are constrained to follow descending trajectories that are typically below the cloud tops. For this reason, the output of the arrival CWAM is a two-dimensional WAF {precipitation intensity, cloud tops}. The performance of arrival CWAM is evaluated by an independent dataset, where the sensitivity of the model to terminal airspace structure and weather forecast horizon are investigated. The independent dataset contains weather decisions from six convective weather days in a variety of terminal areas (ORD, DFW, DEN, CLT, BOS, JFK/LGA/EWR, DCA/IAD). The most descriptive features of pilot avoidance of convective weather are precipitation intensity and storm height, where a 4 km spatial filter on the 90 th percentile value of each feature corresponds to the best tradeoff between probability of detection and false alarm rate.The performance of the model

Hybrid design for automotive body panels

Scipedia content — Tue, 02 Feb 2021 07:29:34 +0100

The increasing trend for electric mobility adoption brings new challenges to the automotive industry, requiring a new approach to the manufacture processes, materials adopted and adaptation the market needs. The conventional technologies used to manufacture automotive parts imply significant overhead costs (tooling, assembly, etc.) which can only be justified by large series. The need of light and cost effective materials was the driving force of this study, acknowledging that the growth of the electric vehicles market will be driven by price. The study aims to deliver a hybrid design material solution that would offer quality and security to the vehicle, affordable to everyone, developing engineered solutions in terms of design and production process. To the study were considered exterior body panels that are conventionally manufactured by sheet metal stamping or conventional thermoplastic injection, both having associated high investment costs related with tooling. To follow up this case study was defined as constrains that small series should be considered and weight reduction has to be achieved. The adoption of engineered materials leading to hybrid body panel's configuration was studied with increased resistance and reduced weight, using processes with low cost assembly operations and low tooling investment for a start. Structural reinforcement inserts were used on the test case to provide the desired results on the final component behavior. The approach taken considered different materials and methodologies focusing on the use of DCPD RIM components having as baseline the materials used nowadays in the automotive industry for the same type of exterior body panels. For deeper understanding on exterior panels' state of art, an analysis through several vehicle doors was made, analyzing the materials used and their combination. As a result, different combinations of materials were considered as adequate for weight reduction and for production on small production series Virtual simulation of two exterior body panels' solutions was done demonstrating the potential of DCPD as a hybrid solution to deliver structural consistence in conjunction with weigh reduction at a reduced cost. FEDER Funds, through the Operational Programme for Competitiveness Factors - COMPETE under the project 13844. FCT (Fundação para a Ciência e Tecnologia) for PhD scholarship (SFRH / BD / 51119 / 2010) under the scope of the MIT Portugal Program in Engineering Design and Advanced Manufacturing - Leaders for Technical Industries focus area.

Achieving Maximum Crack Remediation Effect From Optimized Hydrotesting

Scipedia content — Tue, 02 Feb 2021 07:11:43 +0100

Hydrostatic testing is a key method for managing SCC in oil and gas pipelines. Benefits are achieved by eliminating defects above a critical size for the hydrotest pressure and hence achieving a post-test period without operating failure. Other benefits are related to temporary growth retardation after hydrotest because of crack tip blunting. Conversely, benefits of such a test could be offset by stable flaw growth in the previously dormant population and growth of cracks during hydrostatic loading. Although this type of growth behaviour has been previously analyzed, it was only assessed from tests in air, which neglects the effects of corrosive environments."/jats:p" "jats:p"Recent research has shown that crack growth can occur during hydrotests at much smaller crack dimensions than those originally analyzed. The adverse effect of hydrotesting is negligible if it initiates crack growth only on large-size cracks that are near the final stage of pipeline life. However, benefits of hydrotest would become uncertain if hydrostatic loading induces crack growth when crack dimensions are relatively small. This reduction in pipeline remaining lifetime by hydrostatic testing can be significant considering the fact that several hydrotests may be performed in the lifetime of a pipeline. Although hydrotests would usually re-condition the crack tip so that a lower crack growth rate can be expected for a limited time, it is questionable whether the reduced growth rate would compensate for the loss of life because of the crack growth during hydrotesting. Therefore, the overall benefits of hydrotesting must be evaluated from the viewpoint of life extension and pipeline safety."/jats:p" "jats:p"Effects of hydrostatic tests in this investigation were analyzed based on two competing morphological conditions at the crack tip before, during and after hydrostatic testing, that is, crack tip blunting and crack tip sharpening. Crack tip sharpening is related to the hydrogen effects and mechanisms of cyclic loading, while the crack tip blunting is attributed to low temperature creep of the pipeline steels. From the investigation, strategies aimed at achieving maximum crack remediation are proposed.

Investigating pedal errors and multi-modal effects: Driving testbed development and experimental analysis

Scipedia content — Tue, 02 Feb 2021 07:11:24 +0100

These days, Intelligent Driver Assistance Systems (IDAS) for driving safety enhancement have an increasingly important role. Although there have been a large amount of related research studies in this area, developing an efficient assistance system, which can perceive and assist the driver in a non-intrusive and naturalistic manner, is still an open question. Due to the diverse characteristics and safety issue of driving, one initial and major difficulty in studying and developing such systems is to have adequate infrastructure testbeds with multi-modal sensing and displays. In this paper, we introduce two multi-modal driving testbeds (including both a real-world vehicle and a driving simulator) that we have been developing for years in our laboratory. Based on these testbeds, we describe two novel joint audio visual driving experiments and databases that we have built for investigating driver pedal misapplication error phenomenon in traffic accident prevention. We will then discuss our analysis towards understanding some factors influencing driver pedal errors including driver workload, sequential effect, and cue modality (i.e. audio visual stimuli) as well as a possibility to predict and mitigate pedal errors to some extent using our approach for modeling and prediction of driver foot behavior.

A fuzzy dual expert system for managing situation awareness in a safety supervisory system

Scipedia content — Tue, 02 Feb 2021 06:52:50 +0100

Safety supervisory systems continue to increase in degree of automation and complexity as operators are decreasing. As a result, each operator must be able to comprehend and respond to an ever increasing amount of available risky status and alert information. They generally have no difficulty in performing their tasks physically but they are stressed by the task of understanding what is going on in the situation. So in the last two decades, situation awareness has been recognized as a critical foundation for successful decision making across a broad range of complex and dynamic systems. This paper develops a fuzzy dual expert system based approach to enhance situation awareness. The proposed approach has ability to support the operators' understanding and assessing the situations, and to deal with uncertainties, applying fuzzy risk assessment concepts.

A Hybrid Control for Automatic Docking of Electric Vehicles for recharging

Scipedia content — Tue, 02 Feb 2021 06:52:09 +0100

International audience; In this paper, we present the architecture of an innovative docking station for electric vehicles recharging and a hybrid control scheme for automatic docking of the vehicles. This work is a part of on-going project concerning the development of a smart charging station for electric vehicles equipped with an automated arm, which connect the vehicle to the charging station, and an infrared beacon system for localizing the automatically maneuvering vehicle in the docking area. The proposed control scheme combines time-optimal (bang-bang) control with continuous time-invariant nonlinear control, which stabilizes the vehicle to a small neighborhood of the docking point. Simulation and experimental results illustrate the effectiveness of the proposed controller.

Context aided multilevel pedestrian detection

Scipedia content — Tue, 02 Feb 2021 06:41:30 +0100

The proposed work, depicts a novel algorithm able to provide multiple pedestrian detection, based on the use of classical sensors in modern automotive application and context information. The work takes advantage of the use of Joint Probabilities Data Association (JPDA) and context information to enhance the classic performance of the pedestrian detection algorithms. The combination of the different information sources with powerful tracking algorithms helps to overcome the difficulties of this processes, providing a trustable tool that improves performance of the single sensor detection algorithms. Context in a rich information source, able to improve the fusion process in all levels by the use of a priori knowledge of the application. In the present work multilevel fusion solution is provided for road safety application. Context is used in all the fusion levels, helping to improve the perception of the road environment and the relations among detections. By the fusion of all information sources, accurate and trustable detection is provided and complete situation assessment obtained, with estimation of the danger that involves any detection. This work was supported by the Spanish Government through the Cicyt projects (GRANT TRA2010-20225-C03-01) and (GRANT TRA 2011-29454-C03-02). CAM through SEGVAUTO-II ( S2009/DPI-1509).

Markov Chain Topological Route Selection

Scipedia content — Tue, 02 Feb 2021 06:28:42 +0100

Vulnerability assessment of water supply network

Scipedia content — Tue, 02 Feb 2021 06:15:44 +0100

With global warming water issue is becoming a mean problem in areas of the south hemisphere where raining is decreasing considerably. As a result, preserving such resource is becoming a crucial task facing the authorities. One of the main ways of preservation is making the water pipelines network as safe as possible from any damages involving lose of water around urban areas in particular those situated within areas prone to seismicity. For this purpose, a method to assess the seismic vulnerability of water pipelines was developed and implemented in a Geographical Information System (GIS), allowing larger water supply network to be covered and studied. This method is based on the identification of the parameters that have an influence on the behaviour of pipelines. Each parameter having a coefficient that represent its influence on the behaviour of the structure, the product of these parameters represent the seismic vulnerability of the section pipe under study. As a result, a proposed classification is obtained allowing the determination of a safe section (green colour), an unsafe section (red colour) and an intermediate situation (orange colour). For a proposed application of the method, a case study for a town in suburb of Algiers is presented within this paper. It concerns the town of Blida. The results are given in the following sections.

Aircraft conflict avoidance : a mixed-integer nonlinear optimization approach

Scipedia content — Tue, 02 Feb 2021 06:07:29 +0100

Detecting and solving aircraft conflicts, which occur when aircraft sharing the same airspace are too close to each other according to their predicted trajectories, is a crucial problem in Air Traffic Management. We focus on mixed-integer optimization models based on speed regulation. We first solve the problem to global optimality by means of an exact solver. The problem being very difficult to solve, we also propose a heuristic procedure where the problem is decomposed and it is locally solved by an exact solver. Computational results show that the proposed approach provides satisfactory results in reasonable time.

Comparison of the fire consequences of an electric vehicle and an internal combustion engine vehicle

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

International audience; Since energy storage systems represent key new technologies in the development of electric vehicles (EV), risks pertaining to them have to be examined closely. Lithium-ion (Li-ion) batteries powering EV contain highly energetic active materials and flammable organic electrolytes, which raise safety questions, different to conventional cars. In case of EV fire, concerns remain about batteries fire behavior, about their impact on the fire growth, about their fire-induced potential toxicity, especially in confined spaces and underground car parks and about their reaction with water in case of firemen intervention. Fire tests were therefore achieved for two French car manufacturers on two battery units, on a full battery pack, on an EV and on an analogous internal combustion engine (ICE) vehicle. Thermal and toxic threat parameters governing the fire risk were quantified. For this purpose, the heat release rate and the effective heat of combustion were determined to qualify the thermal impact whereas the main emitted gases governing the toxic potency of the fire effluents were measured. Fire consequences of an EV and the corresponding ICE vehicle were compared. This paper aims at presenting the main results of these fire tests.

Evaluating Anchor Impact Damage to the Subsea Canyon Chief Pipeline Using Analysis and Full-Scale Testing Methods

Scipedia content — Tue, 02 Feb 2021 05:47:58 +0100

This paper presents findings from a study conducted as part of a joint industry effort involving engineers from Williams Midstream, Stress Engineering Services, Inc., GL Noble Denton, and Saipem America. The purpose of this study was to evaluate the severity of damage inflicted to Williams’ subsea 18-inch x 0.875-inch, Grade X60 Canyon Chief Gas Export Pipeline due to an anchor impact at a water depth of 2,300 feet. The phases of work included an initial assessment after the damage to the deepwater pipeline was detected, evaluating localized damage via finite element analysis based using in-line inspection data, full-scale destructive testing including burst tests, and final efforts included the design and evaluation of a subseadeployed repair sleeve. The study included modeling Saipem’s repair sleeve design accompanied by full-scale destructive testing. Strain gages were used to measure strain in the reinforced dent beneath the sleeve, that were then compared to prior results for the unrepaired dent test results. The work associated with this study represents one of the more comprehensive efforts conducted to date in evaluating damage to a subsea pipeline. The results of the analysis and testing work provided Williams with a solid understanding on the behavior on the damage inflected to the pipeline and what level of performance can be expected from the repaired pipeline during future operation. After the engineering analysis and testing phases of this work were completed, the deepwater pipeline was repaired INTRODUCTION The Williams Canyon Chief 18-inch diameter pipeline was hooked by an anchor in late 2005 at a depth of 2,300 feet. The resulting damage pulled the pipeline laterally 1,500 feet from its original path. Inspection efforts using ROVs at the time of the accident indicated that the pipeline was not leaking. However, in the interest of safety, the pipeline pressure was lowered to approximately 800 psi (15% SMYS, pressure, where SMYS is the Minimum Specified Yield Strength of the pipe material) and allowed to continue operation while a remediation method was developed (the repair was made at a reduced pressure). The intent after remediation work was completed that the pipeline would be returned to the full 3,200 psi (55% SMYS) operating pressure. A minimum level of information was available; however, the clearly-defined objective from Williams was to develop a reinforcing solution to restore integrity to the damaged pipeline that involved a dent having material loss in a bent section of pipe. Sources of information included ROV video footage, in-field measurements using ROV-assisted tools, and in-line inspection data that provided the three-dimensional geometry of the dent. A photograph is provided in Figure 1 was taken using an ROV showing the geometry of the dent. As observed in this figure the coating was relatively intact, although the in-line inspection tool did detect metal loss in the vicinity of the dent. Figure 2 includes a sonar image of the bend in the pipeline, which was overlaid with scale circles used to provide an estimate of the radius of bend. As shown, the radius of the bend was between 35 and 80 feet. After the initial inspection efforts were completed, Williams contracted the services of Stress Engineering Services, Inc. to perform an assessment of the pipeline damage. Finite element analysis, along with and full-scale destructive testing were used to evaluate the damage inflicted to the 18-inch x 0.875-inch, Grade X60 Canyon Chief Gas Export Pipeline. At the time of the incident, the operating pressure was 1,450 psi (25% SMYS)., while the maximum allowable operating pressure (MAOP) is 3,600 psi (62% SMYS). Multiple defects were detected in the pipeline and measured during the in-line inspection, some involving dents with combined metal loss. From among the identified defects the most severe dent defect was selected and evaluated for further study. The assessment included detailed modeling, as well as full-scale destructive testing. In a parallel effort, Williams retained the services of Saipem America to assist in the design, assessment, construction, and deployment of a repair sleeve. The main focus of the testing program was to experimentally quantify the severity of damage inflicted to the pipeline by the anchor snag. The limited finite element modeling supported the experimental work, primarily to size the indenter geometry. In-line inspection data provided by Rosen was used to generate a representative dent defect including the associated metal loss. The repair sleeve, designed by Saipem America, was tested as part of the program, with results being compared between the reinforced and unreinforced dent geometries to evaluate the effectiveness of the repair. The sections of this paper that follow provide details on the finite element modeling work, experimental assessment efforts, and design/fabrication/deployment of the sleeve technology to reinforce the damaged Canyon Chief pipeline. The authors of this paper were able to participate in all phases of this project, spanning the initial assessment of the dent in question after its discovery to actually designing and deploying the repair technology.

Adaptive and predictive control architecture of inland navigation networks in a global change context: application to the Cuinchy-Fontinettes reach

Scipedia content — Tue, 02 Feb 2021 05:35:40 +0100

In this paper, an adaptive and predictive control architecture is proposed to improve the management of inland navigation networks in a global change context. This architecture aims at ensuring the seaworthiness conditions of inland navigation networks, and to improve the efficiency of the water resource management. It is based on supervision and prognosis modules which allow the estimation of the current state of the network, and the forecasting of the extreme event occurrence. According to these indicators and to the management constraints and objectives, control strategies of the inland navigation networks will be adapted to limit the impacts of the extreme events. To achieve this aim, three challenges are considered and discussed in this paper. The first one consists in proposing an accurate modeling approach of navigation reaches which are characterized by large scale, nonlinearities, time delays, unknown inputs and outputs, etc. The second one is to increase the knowledge about potentiality of extreme events, consequences of the climate change. The prediction of these events is rather complex due to their rarity, the spacio-temporal scale of the networks, etc. Finally, the third one is the pooling of the two first contributions, i.e. the model of the system and the knowledge about extreme events. Thus, the resilience of the system and the adaptation of the management strategies could be realized

Peer Reviewed

Document type: Article

Maintaining separation between airliners and RPAS in non-segregated airspace

Scipedia content — Tue, 02 Feb 2021 05:35:01 +0100

Best paper in track award. ATM Seminar Eurocontrol/FAA (2013-06-13)

When an airliner and a Remotely Piloted Air System (RPAS) have conflicting courses that may compromise the minimum safety separation between them, how much in advance should the RPAS start the separation manoeuvre? Which is the optimal heading change that will guarantee the desired separation distance with a minimum reaction time? These same questions can be asked if it is the airliner that performs the separation manoeuvre. In this paper the time reaction margins for both aircraft are analysed assuming they are equipped with Automatic Dependent Surveillance (ADS) systems able to exchange aircraft intents. Due to their small cruise speeds, RPAS manoeuvres must be initiated well before the airliner ones. This leads to some safety buffer in case the RPAS cannot comply with the required change of trajectory or if it becomes suddenly unresponsive (due to an internal failure or because a lost-link situation). The paper also assesses the operational point of view by simplifying the reaction times and conflict geometries by grouping them in a small set of cases, regarding the severity of a loss of separation event.

Award-winning

Runway Incursion Studies in NASA's Future Flight Central

Scipedia content — Tue, 02 Feb 2021 05:30:21 +0100

In recent years the Federal Aviation Administration (FAA) has made reduction of runway incursions a priority for surface operations throughout the national airspace system. In a series of experiments conducted in April 2001, NASA studied alternatives designed to improve the efficient movement of surface traffic and reduce runway incursions at Los Angeles International Airport (LAX). The experiments were conducted in NASA Ames Research Center’s FutureFlight Central (FFC), a full virtual reality air traffic control tower cab simulator. This paper details the lifecycle of the safety studies from design to execution, describes the alternatives that were proposed for runway incursion reduction, and offers a brief summary of the experiment results.

A Case Study of Coordinated Electric Vehicle Charging for Peak Shaving on a Low Voltage Grid

Scipedia content — Tue, 02 Feb 2021 05:26:33 +0100

This paper discusses the impact of coordinated charging of electric vehicles for a peak shaving objective, through an online coordination algorithm, on low voltage grid constraints. The results for uncoordinated and coordinated charging are compared to assess the effect on the peak power demand. Furthermore, an unbalanced load flow analysis is performed on a real low voltage grid to assess the impact on the nodal voltages. The simulation results show a positive impact of coordinated charging for both the peak shaving objective and for voltage deviations. The results show that the coordination algorithm obtains effective results, while only needing a limited amount of communication, measurements and predictive knowledge. ispartof: 2012 3RD IEEE PES INNOVATIVE SMART GRID TECHNOLOGIES EUROPE (ISGT EUROPE) ispartof: IEEE PES Innovative Smart Grid Technologies Europe location:Berlin, Germany date:14 Oct - 17 Oct 2012 status: published

Lateral Buckling Induced by Trawl Gears Pull-Over Loads on High Temperature/High Pressure Subsea Pipeline

Scipedia content — Tue, 02 Feb 2021 05:10:10 +0100

Lateral buckling has become a challenge to deep water and high pressure/high temperature (HP/HT) flowlines. In areas that support major commercial fishing industries (e.g. the North Sea in Norway and Atlantic Margin in UK), there is high possibility of interaction between flowlines and fishing trawl gears. This interaction can expose the flowlines to substantial loads and induce lateral buckling."/jats:p" "jats:p"This paper presents global response of subsea pipeline as a result of trawl gear pull-over loads. The external interference from trawl gear pull-over loads can create substantial imperfection or out-of-straightness on the pipeline and may also generate global lateral buckling. The pull-over loads can also induce excessive bending moments and strains in the buckle region."/jats:p" "jats:p"To be able to understand the global response of the pipeline under pull-over loading conditions, a Finite Element (FE) analysis is carried out based on DNV OS F101 [1], DNV RP F110 [2] and DNV RP F111 [3] using general FE analysis software ANSYS v13. Non-linear transient analysis is used to incorporate the non-linear effects, such as the pipeline material nonlinearity, and the response of a structure under the action of pull-over time-dependent loads [8]."/jats:p" "jats:p"The FE analysis covers two periods of duration, i.e. during pull-over duration and post pull-over duration. The analysis during pull-over duration deals with the pipeline global response as a result of trawl gear pull-over loads. The pipeline is subjected to substantial horizontal and vertical pull-over forces from the trawl gear. For post pull-over duration, the FE analysis was carried out for an additional five seconds. In this period, the pull-over loads are no longer applied. However, the pipeline may expand further due to temperature and pressure loads on pipeline."/jats:p" "jats:p"The FE analysis result shows that the pull-over loads induce out-of-straightness on the pipeline and may cause lateral buckling. The pipeline deforms laterally at the pull-over location. The DNV displacement condition code check is used to check the integrity of the pipeline. The pipeline may in the risk under the trawl gears pull-over loads."/jats:p" "jats:p"This paper also shows the development of lateral buckling on the pipeline under different magnitudes of trawl gear pullover loads and lateral soil frictions. Further work should also take into account different dimension of pipeline, as the variation of operating temperature and pressure and variation of lateral and axial soil friction combinations to obtain better conclusions.

Cooperative transportation system for electric vehicles

Scipedia content — Tue, 02 Feb 2021 05:00:54 +0100

Electric Vehicles (EVs) are being introduced in the market, but batteries reduced energy storage capacity and the lack of a high density charging infrastructure limit their autonomy range. In order to overcome this limitation, we propose developing a new solution enabling drivers to drive longer distances. This will be achieved by integrating some components of the cooperative transport infrastructure (charging system, public transport system and the vehicle), and by increasing driving autonomy through energy consumption reduction obtained with the improvement of driving efficiency. In this work we show how to create a cooperative system in a mobile device to integrate public transportation real time information in an EV. Integration of EVs with public transport system allows extension of driving autonomy beyond the storing capacity of vehicle’s batteries. Supplying information on availability, schedule and price of public transport allows the driver to plan the journey using EV and public transportation in a complementary way, using functions as car parking booking (and charging) and ticket buying. This information is integrated in a mobile device providing the driver with a collaborative holistic approach of different public transportation infrastructure sources, that can be combined with real traffic information, parking places and charging slots and current driver position, to support the driver decision making process. FEDER Funds - Operational Programme for Competitiveness Factors (COMPETE) PTDC/EEA-EEL/104569/2008 and the project MITPT/ EDAM-SMS/0030/2008. Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EEA-EEL/104569/2008, MITPT/EDAM-SMS/0030/2008.

The analysis of congested infrastructure and capacity utilisation at Trafikverket

Scipedia content — Tue, 02 Feb 2021 05:00:17 +0100

Trafikverket analyzes railroad capacity in Sweden. Capacity utilization is calculated annually for the whole system. Capacity utilization remains high in the Swedish railroad network. This paper describes the implementation of the common European standard (for capacity utilization) that the Capacity Leaflet UIC 406 describes. The paper also discusses the Southern Main Line that connects Malmo and Stockhom, in Sweden. The Southern Main Line was congested in 2011. The paper describes the methods used to analyze and aid the congested line.

Setting cooperative relations among terminals at seaports using a multi-agent system

Scipedia content — Tue, 02 Feb 2021 04:52:42 +0100

Trabalho apresentado em 16th IEEE Conference of Intelligent Transportation Systems (ITSC'13), 2013, Haia, Holanda Seaports are gateways between the over sea and the hinterland commerce, where different cargo types are handled at dedicated terminals. Currently, seaports are facing traffic congestion leading to a decrease in its performance. Prior to increase the existing infrastructures in terms of transport capacity between the seaport and the hinterland it is important to improve cooperation among terminals. A multi-agent system to guarantee cooperation among terminals within a seaport is proposed in this paper. A control agent is assigned to each terminal and is responsible for the cargo assignment to the transport capacity at its disposal such that cargo arrives on time at the agreed location. Control agents solve in parallel an optimization problem formulated in accordance to the Model Predictive Control (MPC) strategy. Cooperation among control agents is established using a coordinator agent that updates the transport capacity assigned to each control agent based on the marginal costs provided by all control agents. The proposed framework does not require the exchange of private information and assumes an altruist behavior for all control agents. The proposed approach can perform similarly to a central approach. The framework performance is illustrated with simulation studies considering a seaport composed of 3 container terminals info:eu-repo/semantics/publishedVersion

Conceptual Optimal Design of Airliners with Noise Constraints

Scipedia content — Tue, 02 Feb 2021 04:47:11 +0100

Noise generated by airplane during the takeoff and landing flight phases is a matter of increasing concern for both aviation and aeronautical industries. Air traffic is steadily increasing and airports are operating close to their capacity limit. Airlines are under high pressure from communities surrounding airports to operate quieter airplanes and/or change their operating procedures. For this reason, quieter airplanes will be welcome by the airlines and comply to the expected traffic growth. From an airplane manufacturer point of view, the reduction of noise generated by airplane to acceptable levels is a very challenging task. It is to be expected that such drastic noise reductions will not be achieved by merely working on mitigating noise sources on the airplane in isolated form. Instead, the interactions of noise sources as well as shielding effects have to be taken into account. Airplane noise becomes a configuration issue and thus has to be considered in the conceptual design phase. Quieter airplanes could be charged with some penalties like performance degradation and higher fuel consumption, in the latter case generating more pollutants. In order to carry out the design for a quieter airplane considering all this aspects, it is useful to incorporate a noise assessment methodology into a multi-disciplinary design and optimization framework. This approach is justified because an airplane should not be designed considering just a few requirements. Field performance, stability and control, operating costs, manufacturing costs, passenger comfort, embedded technology, all this must be simultaneously considered for designing an airliner that airlines need. A Parametric Airliner Noise Prediction Architecture (PANPA) has been developed at Instituto Tecnologico de Aeronautica (ITA), which is able to predict noise levels generated by an airliner along arbitrary flight trajectories. The related noise levels are estimated for an observer positioned on ground, as required by certification authorities. The module takes into account major airframe and engine noise sources, as well as diverse effects on sound propagation. A multi-disciplinary integrated conceptual airplane design framework, designated AIDMIM, has been in development for some time at ITA. This framework features a modular structure written in MATLAB® language, which allows for manageable incorporation of additional disciplines and analysis methods to the overall design process. PANPA was integrated into AIDMIN and some design tasks with and without noise constraints were carried out.

Improving safety and sustainability of urban transport surfaces through the recycling of reclaimed extinguishing powders

Scipedia content — Tue, 02 Feb 2021 04:26:01 +0100

Fire resistance of transport surfaces is a crucial aspect, especially in specific contexts such as road and railway tunnels in urban areas. In fact, tunnels are characterized by specific environmental and logistic conditions that make the consequences of a fire event severer. Furthermore, as far as bituminous mixes are concerned (flexible pavements, blankets for railways and rapid transit systems), the fire resistance of bituminous materials can have an outstanding role in terms of safety and security. Indeed, these materials burn at medium temperature (400– 500°C) and release toxic smokes. This fire behaviour makes bituminous pavements unsuitable for tunnel contexts. To this end, many studies tried to demonstrate that, by adding virgin flame-retardant additives, it is possible to improve the performance of bituminous pavements, in terms of mechanical properties and fire resistance. On the other hand, owing to the fact that a sustainable transportation surface needs to comply with environmental issues, meeting the needs of present-day users without compromising those of future generations, the use of recycled materials is becoming more and more relevant. In the light of the above premises, the objective of this study is to evaluate the effects of Reclaimed Extinguisher Powders (REP) on the performance of bituminous mixtures in urban transport surfaces. Fire resistance, mechanistic properties and environmental compatibility were considered. An experimental plan was designed and carried out. Results showed that the addition of REP can improve the fire resistance of asphalt binders and bituminous mixtures, without compromising mechanistic and environmental performance. Practical applications and perspectives in rehabilitation, maintenance, and research are outlined. Recommendations for future studies involving the application and

An Update to the UKOPA Pipeline Damage Distributions

Scipedia content — Tue, 02 Feb 2021 04:14:34 +0100

The United Kingdom Onshore Pipeline Operators Association (UKOPA) was formed by UK pipeline operators to provide a common forum for representing operators interests in the safe management of pipelines. This includes providing historical failure statistics for use in pipeline quantitative risk assessment and UKOPA maintain a database to record this data."/jats:p" "jats:p"The UKOPA database holds data on product loss failures of UK major accident hazard pipelines from 1962 onwards and currently has a total length of 22,370 km of pipelines reporting. Overall exposure from 1952 to 2010 is of over 785,000 km years of operating experience with a total of 184 product loss incidents during this period. The low number of failures means that the historical failure rate for pipelines of some specific diameters, wall thicknesses and material grades is zero or statistically insignificant. It is unreasonable to assume that the failure rate for these pipelines is actually zero."/jats:p" "jats:p"However, unlike the European Gas Incident data Group (EGIG) database, which also includes the UK gas transmission pipeline data, the UKOPA database contains extensive data on measured part wall damage that did not cause product loss. The data on damage to pipelines caused by external interference can be assessed to derive statistical distribution parameters describing the expected gouge length, gouge depth and dent depth resulting from an incident. Overall 3rd party interference incident rates for different class locations can also be determined. These distributions and incident rates can be used in structural reliability based techniques to predict the failure frequency due to 3rd party damage for a given set of pipeline parameters."/jats:p" "jats:p"The UKOPA recommended methodology for the assessment of pipeline failure frequency due to 3rd party damage is implemented in the FFREQ software. The distributions of 3rd party damage currently used in FFREQ date from the mid-1990s. This paper describes the work involved in updating the analysis of the damage database and presents the updated distribution parameters. A comparison of predictions using the old and new distributions is also presented.

Why people use their cars while the built environment imposes cycling

Scipedia content — Tue, 02 Feb 2021 03:56:58 +0100

Residing in a high-density, diverse, and accessible neighborhood tends to be associated with less car use, more public transport, and more cycling and walking. However, this does not hold for all people because of differences in personal perceptions and preferences. This paper, therefore, analyzes spatial (mis)match, or the correspondence between perceptions of someone’s residence and the objectively measured spatial characteristics of that residence. Based on a sample for Flanders, Belgium, we found that people tend to overrate the urbanized character of their residence. Among urbanites, (mis)matched spatial perceptions do not influence mode choice. Mode choices remain mainly influenced by urban characteristics and not by personal perceptions as such. However, the influence of spatial (mis)match becomes more important among rural dwellers and, especially, suburbanites. The travel consequences of (mis)matched spatial perceptions thus clearly depend on the residential neighborhood type.

Review of existing transportation sustainability initiatives and their applicability to Qatar

Scipedia content — Tue, 02 Feb 2021 03:52:34 +0100

Sustainable development is Qatar's main national goal. The fact that Qatar has secured the World Cup bid for 2022 will make it the first Arab country to host the world cup. This honor and Qatar's plan to advance its development has led the state to start upgrading its entire transportation infrastructure. Qatar's commitment to sustainability and the state's upcoming investments in the transportation sector has led the authors to investigate current transportation sustainability assessment systems, which can be transferred to Qatar. A thorough literature review revealed that the current initiatives have a number of limitations that render them inapplicable to Qatar. This paper presents these findings and suggests the main features of a sustainability rating system applicable to Qatar. This will be the first step in developing the Qatar Transportation Sustainability Assessment System (QTS). Scopu

Failure Risk of Bar-Wrapped Pipe with Broken Bars and Corroded Cylinder

Scipedia content — Tue, 02 Feb 2021 03:50:04 +0100

Bar-wrapped pipe (“BWP”) commonly used in pressure pipelines due to its reliability, cost effectiveness and durability. Failure of BWP can occur as a result of long term leakage and subsequent corrosion or as a result of leakage and deterioration of the reinforcing bars over time. The failure can also be the direct result of a transient pressure or other sudden catastrophic events. The consequence of failure may result in a significant disruption of operation and service for a water utility without any warning. This is a concern because assessing the condition of a damaged BWP is very challenging. In this paper, a nonlinear finite element analysis was used to evaluate the performance of a damaged BWP. For the structural evaluation, stresses and strains developed in the damaged BWP were evaluated. Cracking and spalling of the mortar lining will eventually lead to the corrosion of the steel components. In an effort to account for the steel deterioration, the model was adjusted by reducing the thickness of the steel cylinder. This study investigates the behavior of a deteriorating BWP under various levels of distress and various internal pressures. The results based on a 24-inch pipe transmission main, are used to define criteria to evaluate the performance of a damaged BWP. Based upon the finite element results obtained in this study, suggestions for future work are presented and discussed.

Efficiency of transport infrastructure and ICT development

Scipedia content — Tue, 02 Feb 2021 03:38:15 +0100

This study examines the impact of ICT growth on the productivity effects of transportation infrastructure. Using dynamic panel data of OECD member countries, the study finds econometrically meaningful results on examining the complementarity between ICT and transportation infrastructures. The network effect of growth of motorway infrastructure in advanced countries tends to accelerate when the ICT network grows beyond a certain threshold level.

Strip-TIC : exploring augmented paper strips for Air Traffic Controllers

Scipedia content — Tue, 02 Feb 2021 03:15:46 +0100

International audience; The current environment used by French air traffic controllers mixes digital visualization such as radar screens and tangible artifacts such as paper strips. Tangible artifacts do not allow controllers to update the system with the instructions they give to pilots. Previous attempts at replacing them in France failed to prove efficient. This paper is an engineering paper that describes Strip-TIC, a novel system for ATC that mixes augmented paper and digital pen, vision-based tracking and augmented rear and front projection. The system is now working and has enabled us to run workshops with actual controllers to study the role of writing and tangibility in ATC. We describe the system and solutions to technical challenges due to mixing competing technologies.

Real-time information extraction of an electric vehicle

Scipedia content — Tue, 02 Feb 2021 03:14:46 +0100

In this paper is presented the development of a project to extract, in real-time, information’s related with an Electric Vehicle (EV). This project was elaborated to extract data from an EV battery charging device developed at the University of Minho, and from an EV prototype, the VEECO (Veículo Eléctrico ECOlógico – Ecologic Electric Vehicle), developed in a cooperation project of ISEL (Lisbon Superior Institute of Engineering) and the Portuguese company VE. The main goal of this project consists in collecting and transmitting the extracted data to inform the EV driver about the performance and the real behavior of the EV. Thereby, it is created an open interface to manage, in real-time, the main data related with the EV, as the batteries SoC (State-of-Charge), the EV speed, and internal temperatures (like the temperatures of the batteries, motor and power electronics inverter), as well as to control the start and stop of the batteries charging process, and to optimize the charging program (to define the best algorithm to preserve the batteries lifespan). This interface also controls the discharging process of the batteries, in order to make possible to deliver back to the electrical power grid part of the stored energy in the batteries, which is defined by the concept Vehicle-to-Grid (V2G). In the paper are presented and described the two main parts of this work: the real-time information extraction system and the charging device. FEDER Funds - Operational Programme for Competitiveness Factors (COMPETE) Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EEA-EEL/104569/2008, MITPT/EDAM-SMS/0030/2008.

Implementation of Magnetic Meters for Irrigation Volumetric Measurement

Scipedia content — Tue, 02 Feb 2021 03:12:07 +0100

The irrigation industry is experiencing a growth in the use of magnetic meters for measuring the flow rate and volume in irrigation pipelines. Historically, propeller meters have been the device selected by users. New legislation in California (SB7x7) will require measurement devices at key locations for irrigation water delivery. Some users are very interested in the magnetic meter for making the measurement at the turnout or farm gate. The key feature of the new meter is the ability for the device to work in less than ideal flow conditions. Electromagnetic meters have been tested by the Irrigation Training and Research Center in lab and field pipelines located less than the 10 diameters upstream of disturbances with good results. There are several manufacturers that are selling units to the irrigation market as well as several types of magnetic meter designs. This paper discusses how a magnetic flow meter works, advantages/disadvantages of this type of meter, test results, and new guidelines for field applications.

Coverage search in 3D

Scipedia content — Tue, 02 Feb 2021 03:11:06 +0100

Searching with a sensor for objects and to observe parts of a known environment efficiently is a fundamental prob- lem in many real-world robotic applications such as household robots searching for objects, inspection robots searching for leaking pipelines, and rescue robots searching for survivors after a disaster. We consider the problem of identifying and planning efficient view point sequences for covering complex 3d environments. We compare empirically several variants of our algorithm that allow to trade-off schedule computation against execution time. Our results demonstrate that, despite the intractability of the overall problem, computing effective solutions for coverage search in real 3d environments is feasible. "p"Accepted for Publication."/p" ELLIIT CADICS CUAS SHERPA

TrafficCam: Sharing traffic information based on dynamic IPv6 multicast group assignment using smartphone sensors

Scipedia content — Tue, 02 Feb 2021 02:54:46 +0100

Exchanging traffic information among nearby vehicles is one of the communication scenarios in the field of intelligent transport systems (ITS). An important question in this scenario is “How can traffic information be delivered to only one subset of nearby vehicles in the same road traffic situation?”, for example, to only congested traffic in a certain lane. In this demonstration, we propose a dynamic IPv6 multicast group assignment mechanism using GPS, an accelerometer and a magnetometer embedded in smartphones. Our mechanism enables each vehicle to find the relevant vehicles, and to compose a temporary IPv6 multicast address. Our mechanism can deliver traffic information to a group of vehicles in a particular situation. This demonstration, carried out on virtual traffic congestion, shows an information-sharing scenario using a prototype of the proposed mechanism, implemented as an Android application called TrafficCam. Our application demonstrates the usefulness of the proposed mechanism.

Towards fine-grained urban traffic knowledge extraction using mobile sensing

Scipedia content — Tue, 02 Feb 2021 02:51:53 +0100

We introduce our vision for mining fine-grained urban traffic knowledge from mobile sensing, especially GPS location traces. Beyond characterizing human mobility patterns and measuring traffic congestion, we show how mobile sensing can also reveal details such as intersection performance statistics that are useful for optimizing the timing of a traffic signal. Realizing such applications requires co-designing privacy protection algorithms and novel traffic modeling techniques so that the needs for privacy preserving and traffic modeling can be simultaneously satisfied. We explore privacy algorithms based on the virtual trip lines (VTL) concept to regulate where and when the mobile data should be collected. The traffic modeling techniques feature an integration of traffic principles and learning/optimization techniques. The proposed methods are illustrated using two case studies for extracting traffic knowledge for urban signalized intersection.

Enabling Sleep Mode in Backbone IP-Networks: a Criticality-Driven Tradeoff

Scipedia content — Tue, 02 Feb 2021 02:41:22 +0100

International audience; The energy consumption of network devices, and, as a consequence, of communication networks, is generally independent from their level of utilization, which results in a waste of energy when the network is lightly loaded. Ideally the consumption of a network should be proportional to the amount of traffic it conveys. The most straightforward way to enforce such a proportionality between the network energy consumption and its utilization level, is to dynamically adapt the status of network devices to the load, forcing a subset of them to enter a sleep state during the low activity periods. We present in this paper an algorithm to dynamically put links into a sleep state, based on a cooperative-game approach, named "L-Game". Our approach decides which links can be switched off based on a measure of the criticality of each link expressed as its Shapley value. This measure combines topological aspects and traffic conditions. Simulation results on real network scenarios show that our solution achieves a better trade off between energy saving and Traffic Engineering than other legacy approaches.

NASA's ATM technology demonstration-1: Integrated Concept of arrival operations

Scipedia content — Tue, 02 Feb 2021 02:22:38 +0100

This paper describes operations and procedures envisioned for NASA's Air Traffic Management (ATM) Technology Demonstration #1 (ATD-1). The ATD-1 Concept of Operations (ConOps) demonstration will integrate three NASA technologies to achieve high throughput, fuel-efficient arrival operations into busy terminal airspace. They are Traffic Management Advisor with Terminal Metering (TMA-TM) for precise time-based schedules to the runway and points within the terminal area, Controller-Managed Spacing (CMS) decision support tools for terminal controllers to better manage aircraft delay using speed control, and Flight deck Interval Management (FIM) avionics and flight crew procedures to conduct airborne spacing operations. The ATD-1 concept provides de-conflicted and efficient operations of multiple arrival streams of aircraft, passing through multiple merge points, from top-of-descent (TOD) to touchdown. It also enables aircraft to conduct Optimized Profile Descents (OPDs) from en route altitude to the runway, using primarily speed control to maintain separation and schedule. The ATD-1 project is currently addressing the challenges of integrating the three technologies, and implantation into an operational environment. Goals of the ATD-1 demonstration include increasing the throughput of high-density airports, reducing controller workload, increasing efficiency of arrival operations and the frequency of trajectory-based operations, and promoting aircraft ADS-B equipage.

Scalable On-Demand Network Management Module for Software Defined Telecommunication Networks

Scipedia content — Tue, 02 Feb 2021 02:16:28 +0100

The design of telecommunication networks and its provisioning is a challenging and complex task, which is constantly influenced by various factors. The disciplines of Traffic Engineering (TE) and Network Management (NM) have addressed these domains with static, semi-automatic and pure self-organizational approaches. Most of the existing approaches usually either relax the problem by taking strong assumptions on the problem instances or by only taking a small portion of the solution space into consideration, thus losing the chance of proving any global optimality gaps. The emerging cloud hosted flexible telecommunication system addressed by the industry nowadays puts new requirements on TE and ND. Current, telecommunication networks are often statically deployed and over-provisioned to cover pre-defined peak data rates, but are inflexible to adapt to dynamic network load situations. This paper presents novel dynamic Traffic Engineering (TE) and adaptive Network Management (NM) approaches for software defined telecommunication networks, which reduce Operational - and Capital Expenditures (OPEX/CAPEX), but also enhance the level of flexibility and elasticity at the same time.

A spatial database for reroute planning

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

Current storage and retrieval of air traffic management data by the FAA allows for sufficient control of aircraft flows in the National Airspace System. However, these storage methods allow neither for deep historical analysis nor for use of advanced, standards-compliant tools. Another shortcoming of these storage methods is that air traffic management data are not readily accessible by all interested parties. The contributions of this paper are a new approach to describing, storing, and serving air traffic management data, and its software implementation. This approach is compliant with relevant published standards and, therefore, is easily incorporated into current and future systems. We fully develop a schema for describing reroute advisories, implement a database based upon that schema, then implement an example tool that can use this new system to provide information in a way not possible in the current system. This schema is an extension of the Aeronautical Information Exchange Model and allows for geometric queries to databases based upon the model. The example tool uses this feature by requesting previously implemented reroutes that do not intersect a supplied region of interest. The results enable a traffic manager to base a new reroute on past decisions of all traffic managers, which is not an approach used today. In today's operations, the sharing of past decisions between traffic managers given similar situations is not a formal process. The disconnect between what various managers might implement leaves room for inefficiencies in the system and helps motivate this study. As an example of the potential benefits of the system described here, there was a savings over 1000 nmi in total flight distance over all flights affected by a particular reroute advisory.

ISIS+: A realistic ATM-UAS simulation environment

Scipedia content — Tue, 02 Feb 2021 01:54:39 +0100

Unmanned Aircraft Systems (UAS) are currently being used primarily for military applications, but with the evolution of avionics technology, a huge market in civil applications is emerging. However, most civil applications require UAS to access non-segregated airspace. Current use limitations of non-segregated airspace make it extremely difficult to extensively evaluate operational concepts and mission profiles. Using real flights to test the complete UAS mission infrastructure involves costs and risks. Therefore, simulators must be used prior to real flight campaigns to test and validate UAS components and must take into account all the actors involved in the non-segregated airspace. This paper describes the development of a Software-in-the-Loop simulator called ISIS+ to evaluate the automated operations of UAS in non-segregated airspace and to test new software components of the UAS with other avionics components. The ISIS+ simulator provides a realistic simulation environment in which the UAS software components can be developed under real air traffic scenarios while taking into account all the UAS's peculiarities. The UAS is integrated with eDEP, an air traffic simulation environment, in order to explore the UAS behavior, conflicting traffic and air traffic controllers' requests with the airspace actors. The integration is carried out using ADS-B messages and considers the UAS as an active actor in the networked environment to simulate future SESAR and NextGen scenarios.

Peer Reviewed

Understanding Vehicle Related Crime to Elaborate on Countermeasures Based on ADAS and V2X Communication

Scipedia content — Tue, 02 Feb 2021 01:48:27 +0100

mong numerous types of criminal activities, vehicle related crime contributes to personal injury as well as to economic losses. Over the last 10 years vehicle related crime continuously constitutes over 10% of all crime in Germany. However, vehicle related crime is not particularly a German phenomenon but even more a worldwide problem which does not respect national borders. Meanwhile, connected mobility gains importance and vehicles are increasingly equipped with advanced driver assistance systems (ADAS). Additionally, the penetration of consumer electronics (CE) increases constantly. Hence, it seems promising to use these new technologies to tackle vehicle related crime. But to be able to apply these new technologies successfully against vehicle related crime, a systematic approach to understand these crimes in detail is necessary. To address this challenge, we apply two criminological theories, Rational Choice Perspective and Situational Crime Prevention, to the vehicle related context. We also provide an innovative idea for a countermeasure based on information and communication technologies (ICT).

On-Bottom Stability Analysis for a Pipeline on a Mobile Seabed

Scipedia content — Tue, 02 Feb 2021 01:37:17 +0100

This paper describes the work performed to assess the stability of an existing pipeline off the North Western coast of Western Australia. Originally, the pipeline was post-trenched (for stability), by ploughing. The plough formed an open v-shaped trench below the pipeline. Several years after the pipeline was installed, a severe cyclone caused significant changes to the seabed along the pipeline. The v-shaped ploughed trench is generally no longer visible with the trench backfilled in places and the pipeline exposed in others. In addition to this, the embedment profile either side of the pipeline was often found to be assymetrical, with higher embedment on one side of the pipeline relative to the other."/jats:p" "jats:p"Current on-bottom stability guidelines and recommended practices do not account for the effects of assymetrical embedment and seabed mobility (Ref. 5). These two factors are believed to contribute significantly to the overall stability of the pipeline. Consequently, it was decided to use physical model testing to obtain a better understanding of hydrodynamic loading and changes in embedment over the duration of a design storm. The physical model testing was performed for various pipeline embedment profiles. The results of these 2D physical model tests were then applied to the 3D FEA on-bottom stability software, CORUS 3D."/jats:p" "jats:p"This paper provides a detailed description of the physical model testing program performed as part of the pipeline stability assessment. The method used to combine the results of the physical model testing and apply them to the 3D FEA on-bottom stability software is also presented.

Research on Sustainable Development Evaluation method of City Road-Network

Scipedia content — Tue, 02 Feb 2021 01:37:01 +0100

Key : words Traffic engineering; sustainable development; analytic hierarchy process; city traffic Abstract. According to the spatial distribution characteristics of the network is divided into sections and intersections of City road-network , according to the distribution of traffic flow characteristics an reference of relevant standards at home and abroad, the city traffic sustainable development degree is divided into 5 grades, selected the city sustainable development indicators, using analytic hierarchy process to establish traffic sustainable development two level evaluation index system and the corresponding fuzzy comprehensive evaluation model, and finally to a specific network traffic can develop continuously undertook determining. The research results for the assessment of city traffic sustainable development provided a kind of effective quantitative analysis method. At present, the city traffic sustainable development quantitative description has no unified standards, mainly to saturation, speed, density or fleet retention length to judge, although these amount to a certain extent the road network traffic can develop continuously undertook certain expressions, they don't reflect the traffic sustainable development - what is the essence of the road traffic is a serious waste of resources, or imbalance of traffic order. Transport aims to make people and objects are efficient, fast, convenient moving, but regardless of is the saturation, or speed or density are not accurately, effectively describe network traffic sustainable development degree, then based on the concept of traffic congestion mitigation strategy is also not really solve the congestion problem ) 6 1 ( − . Therefore, it is important to Judge network traffic sustainable development research, it can provide traffic management departments by accurate traffic data. Appropriate to the outlet of network traffic sustainable development measures, can provide a meaningful reference, avoiding the city traffic construction expands blindly and money and waste of resources.

SACAT: An instrumented vehicle for driver assistance and safety

Scipedia content — Tue, 02 Feb 2021 01:27:51 +0100

The present paper describes the framework and components of an instrumented vehicle for driver assistance and safety. The experimental platform is based on the use of an on-board computer vision system to capture the traffic signs, and on a multiple of electronic components to capture the vehicle state and identify drivers. The hardware architecture is designed with the purpose of making the deployment of functionalities related to driver assistance and road safety easy. The paper covers firstly the description of the hardware architecture, and then describes some of the implemented functionalities such as driver assistance based on traffic signs detection and recognition, traffic violation recorder, and a realization of an emergency call system. Manuscript received 15 February, 2012. This work was supported in part by the Regional Government of Madrid under the S2009/DPI-1509-SEGVAUTO grant, and the PN I+D+i under the TRA2010-20225-C03-02 SAMPLER grant.

Opportunistic system for collaborative traffic monitoring using existing IEEE 802.11 networks

Scipedia content — Tue, 02 Feb 2021 01:25:22 +0100

Traffic monitoring and control is getting more and more important as the number of vehicles and traffic jams steadily grow. Nevertheless, traffic control is still predominantly done by visual means using strategically placed video cameras. To be more effective, proposals to improve the traffic conditions should consider automated monitoring systems. This work proposes an opportunistic system for collaborative traffic monitoring using available IEEE 802.11 networks. Based on the information received by 802.11 beacon frames, vehicles provide the data needed by a central entity to handle and disseminate information about traffic conditions on urban roads, exploiting readily available network resources. Experiments performed with data from a real public wireless network, in Rio de Janeiro, demonstrate the possibility of obtaining traffic conditions with our proposed traffic monitoring method. The system results are close to GPS traces. Moreover, the proposed system facilitates large-scale adoption since it does not require specific hardware.

A Linear Programming Approach to the Development of Contrail Reduction Strategies Satisfying Operationally Feasible Constraints

Scipedia content — Tue, 02 Feb 2021 01:23:15 +0100

class of strategies has been proposed to reduce contrail formation in the United States airspace. A 3D grid based on weather data is built and the cruising altitude level of aircraft is adjusted to avoid the persistent contrail potential area with the consideration to fuel-eciency. In this paper, the authors introduce a contrail avoidance strategy on 3D grid by considering additional operationally feasible constraints from an air trac controllers aspect. First, shifting too many aircraft to the same cruising level will make the miles-in-trail at this level smaller than the safety separation threshold. Furthermore, the high density of aircraft at one cruising level may exceed the manageable workload for the trac controller. Therefore, in our new model we restrict the number of total aircraft at each level. Second, the aircraft count variation for successive intervals can not be too drastic since the workload to manage climbing/descending aircraft is much larger than managing cruising aircraft. The contrail reduction problem is formulated as integer programming and the problem is shown to have the property of total unimodularity. Solving the corresponding relaxed linear programming with the simplex method provides an optimal and integral solution to the problem. Simulation results are provided to illustrate the methodology.

A track-to-track association method for automotive perception systems

Scipedia content — Tue, 02 Feb 2021 00:50:34 +0100

Recent and future driver assistance systems use more and more sensors, that have individual tracking modules. For target tracking, it becomes necessary to find techniques to manage as simply as possible the use of a great number of independent and heterogeneous sensors, at the different stages of the process. This paper presents a modular highlevel track-fusion architecture for a multisensor environment. This architecture allows the variation of the number and the types of the used sensors with no major change in the tracking algorithm. The paper also tackles the multisensor track-to-track association issue with a new algorithm based on a particular track-to-track distance computation. An example of target tracking method is shown to make use of the proposed architecture and the track-to-track association algorithm.

Smart battery charger for electric mobility in smart grids

Scipedia content — Tue, 02 Feb 2021 00:49:38 +0100

In this paper is presented the development of a smart batteries charger for Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs), aiming their integration in Smart Grids. The batteries charging process is controlled by an appropriate control algorithm, aiming to preserve the batteries lifespan. The main features of the equipment are the mitigation of the power quality degradation and the bidirectional operation, as Grid-to-Vehicle (G2V) and as Vehicle-to-Grid (V2G). During the charging process (G2V), the consumed current is sinusoidal and the power factor is unitary. Along the discharging process (V2G), when the equipment allows delivering back to the electrical power grid a small amount of the energy stored in the batteries, the current is also sinusoidal. The V2G mode of operation will be one of the main features of the Smart Grids, both to collaborate with the electrical power grid to increase stability, and to function as a distributed Energy Storage System (ESS). The functioning of the smart batteries charger is shown through simulation and experimental results, both during the charging (G2V) and the discharging (V2G) modes of operation. Also in this paper are shown and briefly described the roles of the key concepts related with the Smart Grids in terms of Systems and Functional Areas, Power Electronics Systems, and Electric Mobility. This work is financed by FEDER Funds, through the Operational Programme for Competitiveness Factors – COMPETE, and by National Funds through FCT – Foundation for Science and Technology of Portugal, under the project PTDC/EEA-EEL/104569/2008 and the project MIT-PT/EDAM-SMS/0030/2008.

Air-traffic conflict resolution via B-splines and semi-infinite programming

Scipedia content — Tue, 02 Feb 2021 00:19:49 +0100

National audience; The most critical point of air-traffic control is to ensure safety separation between airplanes. To achieve this goal, a safety standard separation distance has been defined : 5 Nm (Nautical miles) horizontally and 1000 feet vertically. Air traffic controllers are responsible for ensuring the respect of these separation rules. Air traffic being constantly increasing, controllers in charge of an aviation sector must handle more and more flights. Nowadays, air-traffic management (ATM) has already used every available ressource to increase airspace capacity. From now to 2030, air-traffic is expected to be further multiplied by a factor two or three [1]. Consequently, ATM will have to deal with this overload while ensuring at least equivalent standards of safety [1].

Is urban logistics pooling viable? A multistakeholder multicriteria analysis

Scipedia content — Tue, 02 Feb 2021 00:19:15 +0100

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

Container based calculation of greenhouse gas emissions. A method to determine emissions of container handlings in container terminals: Paper presented at 13th World Conference on Transport Research, WCTR 2013, July 15-18, 2013, Rio de Janeiro, Brazil

Scipedia content — Tue, 02 Feb 2021 00:16:30 +0100

The container transport is the key factor for globalized markets. Due to this the shipping volume in the past 20 years grew by the factor of 5. Based on this, container terminals are very important transshipment facilities in global transport chains with a high amount of annual throughput and greenhouse gas (GHG) emissions. The transport sector is responsible for a large proportion of GHG emissions. An increase of traffic and GHG emissions for any transport mode is estimated. However, emissions are caused by transport modes and transshipment facilities and have to be reduced for both. State of the Art methods of determining transportation caused emissions consider only transportation modes. Emissions in transshipment facilities were currently rarely applied. However, for calculating emissions along the entire transport chain, the emissions from transshipment facilities have to be taken into account. Furthermore the reduction of greenhouse gases is significant for both the terminal itself and for the entire transport chain. Derived from existing standards for calculation of GHG emission a calculation tool for container terminals has been developed. Based on the energy consumption of the handling equipment and storage facilities the tool calculates the overall emissions in terminals. Furthermore, these emissions are allocated to loading units by using overall handling data and handling factors. The developed tool can be adapted to any multimodal container terminal. The calculated results of the tool include total emissions and the allocation of emissions on loading units.

Fiber Optic Monitoring of Subsea Equipment

Scipedia content — Tue, 02 Feb 2021 00:14:49 +0100

Bass Lite deepwater field in the Gulf of Mexico, at water depths of approximately 2,050 m (6,750 feet), commenced operation in February 2008. Natural gas is produced from Bass Lite via a 90-km (56-mile) subsea tieback to the Devils Tower Spar. This project involved several innovations, one of which was the incorporation of a fiber optic sensing system that measures real-time temperature, pressure and strain along the pipeline length. This is a first of its kind innovation that is in actual operation.Copyright © 2012 by ASME

Seismic Design Guidelines to Mitigate Upheaval Buckling of Small Diameter Pipes

Scipedia content — Mon, 01 Feb 2021 23:58:34 +0100

This paper describes The Draft Seismic Design Guidelines to Mitigate Upheaval Buckling of Small Diameter Pipes which were reported by Ministry of Economy, Trade and Industry in 2011. Upheaval buckling of small diameter gas pipes occurred in a high-pressure gas pipeline and three middle-pressure city lines due to the strong ground motion during the 2007 Niigata Chuetsu Offshore earthquake which was a powerful earthquake with moment magnitude of 6.6. A three year research program had been conducted since 2008 to investigate the upheaval buckling behaviors and develop seismic design guidelines to ensure seismic integrity of small diameter high-pressure gas pipelines and middle-pressure main distribution lines.Copyright © 2012 by ASME

The Efficient Descent Advisor: Technology Validation and Transition

Scipedia content — Mon, 01 Feb 2021 23:58:17 +0100

NASA recently completed the development and testing of the Efficient Descent Advisor (EDA) ‐ a trajectory-based tool for en route air traffic controllers that computes Optimized Profile Descent (OPD) solutions designed to minimize aircraft fuel consumption and associated carbon dioxide emissions while maximizing airspace throughput. EDA was developed and refined through a series of high fidelity Human-in-the-Loop (HITL) simulations, carried out in a three-year effort with the FAA and Boeing known as 3D-Path Arrival Management (3D-PAM). A final simulation was carried out to assess potential benefits using a prototype that reflected a culmination of previous design decisions. The simulation compared EDA against baseline operations in which controllers were provided with scheduling automation alone, representing metering operations today. For added fidelity, the simulation included models of trajectory prediction uncertainty. Results showed that EDA enabled a 92% improvement in the accuracy by which controllers delivered aircraft to the terminal airspace boundary in conformance with metering schedules. In addition, with EDA, controllers were able to accommodate overtake maneuvers en route without adjustments to the optimal arrival sequence. Furthermore, EDA was shown to reduce fuel consumption in transition airspace by 110 lbs per flight, averaged for all aircraft types and traffic scenarios, with substantially more fuel savings observed for busier traffic conditions and larger aircraft types. Reductions in controller workload were also observed along with a 60% reduction in the number of required maneuver instructions between controllers and pilots. Results from this simulation and previous experiments, together with prototype software and design specifications, were delivered to the FAA for transitioning EDA towards operational deployment.

An Automotive Side-View System Based on Ethernet and IP

Scipedia content — Mon, 01 Feb 2021 23:49:37 +0100

Emerging driver assistance systems pose new requirements on the communication protocols. This is especially true for assistance systems based on cameras as sensors. This paper discusses the challenges of such systems using the Side View system, which uses five cameras as input, as an example. Standard and potential communication protocols are evaluated with respect to these challenges in this paper. The paper argues why Ethernet and IP form a suitable basis for new driver assistance systems and describe a first prototypical implementation of the Side View system.

The Application and Analysis of Data Mining in Clustering Data of Petroleum Pipeline

Scipedia content — Mon, 01 Feb 2021 23:45:04 +0100

dopting the methods of the K-means and the SOFM neutral network in the data mining and basing on the characteristics of data of petroleum pipeline, a system is built that fits for the data mining and the evaluation on the effects of the clustering data. It is shown that the effects of this data mining are the best by comparison between the two results of the clustering data by using the multiple regression analysis. Keywords-Data mining, K-means, SOFM neutral network, Multiple regression analysis. I. INTRODUCTION The data mining makes the database technique enter into a higher stage. It can not only query and ergodic the past data but also find out the potential connections between the past data. Thus it can promote the transmission of the information. Today, data mining technology is mainly applied in the classifying, clustering and forecasting areas(1). This paper adopts the clustering K-means and SOFM neutral networks. In the oil and gas industry, pipeline transport grows rapidly in the present worldwide. There is an obvious advantage of the pipeline transport over others in the transportation of the oil and gas. The oil transport is an important link in the normal operation of this industry, and it preserves large amount of statistics as well, which provides a great deal of information for the analysis of the whole oil transportation(2). So, analyzing the data of petroleum pipeline by using the clustering algorithm in the data mining is helpful to the thorough research on the fault identification of the pipeline, diagnosis and forecast, the safety of the transport, the response to accidents, the price making after interconnection reconstruction.

Dynamic model development of performance indices for planning of sustainable transportation systems

Scipedia content — Mon, 01 Feb 2021 23:38:06 +0100

Sustainability has recently become a very important research area in transportation because of the dependencies between transportation, economic and environmental system. A lot of research is taking place in various aspects that try to understand the interdependencies. However, there is a need to capture the behavior of such systems over time. The research presented in this paper is the first attempt to build dynamic models that try to capture the interdependent behavior of these systems. The research is influenced and motivated by the predator-prey models developed by renowned researchers Lotka and Volterra. The current study is performed to capture the interaction between interdependent systems i.e. transportation system, activity system, and environmental system. To study the interactions from a macro-scale, this research emphasizes non-linear modeling techniques to capture the nominal behavior of all the three systems. The results indicate that the performance of transportation system and the activity system follow a periodic behavior with phase lag, while the performance of environment system decreases with time. The modeling approach proposed in this research will be helpful to other researchers so that they can modify and enhance such models for proper analysis of sustainable systems.

Anytime Algorithms for GPU Architectures

Scipedia content — Mon, 01 Feb 2021 23:37:02 +0100

Most algorithms are run-to-completion and provide one answer upon completion and no answer if interrupted before completion. On the other hand, anytime algorithms have a monotonic increasing utility with the length of execution time. Our investigation focuses on the development of time-bounded anytime algorithms on Graphics Processing Units (GPUs) to trade-off the quality of output with execution time. Given a time-varying workload, the algorithm continually measures its progress and the remaining contract time to decide its execution pathway and select system resources required to maximize the quality of the result. To exploit the quality-time tradeoff, the focus is on the construction, instrumentation, on-line measurement and decision making of algorithms capable of efficiently managing GPU resources. We demonstrate this with a Parallel A* routing algorithm on a CUDA-enabled GPU. The algorithm execution time and resource usage is described in terms of CUDA kernels constructed at design-time. At runtime, the algorithm selects a subset of kernels and composes them to maximize the quality for the remaining contract time. We demonstrate the feedback-control between the GPU-CPU to achieve controllable computation tardiness by throttling request admissions and the processing precision. As a case study, we have implemented AutoMatrix, a GPU-based vehicle traffic simulator for real-time congestion management which scales up to 16 million vehicles on a US street map. This is an early effort to enable imprecise and approximate real-time computation on parallel architectures for stream-based timebounded applications such as traffic congestion prediction and route allocation for large transportation networks.

Multi-Agent Reinforcement Learning for Integrated Network of Adaptive Traffic Signal Controllers (MARLIN-ATSC)

Scipedia content — Mon, 01 Feb 2021 23:36:34 +0100

Traffic congestion in Greater Toronto Area costs Canada $ 6 billion /year and is expected to grow up to $ 15 billion /year in the next few decades. Adaptive Traffic Signal Control(ATSC) is a promising technique to alleviate traffic congestion. For medium-large transportation networks, coordinated ATSC is becoming a challenging problem because the number of system states and actions grows exponentially as the number of networked intersections grows. Efficient and robust controllers can be designed using a multi-agent reinforcement learning (MARL) approach in which each controller (agent) is responsible for the control of traffic lights around a single traffic junction. This paper presents a novel, decentralized and coordinated adaptive real-time traffic signal control system using Multi-Agent Reinforcement Learning for Integrated Network of Adaptive Traffic Signal Controllers (MARLINATSC) that aims to minimize the total vehicle delay in the traffic network. The system is tested using microscopic traffic simulation software (PARAMICS) on a network of 5 signalized intersections in Downtown Toronto. The performance of MARLIN-ATSC is compared against two approaches: the conventional pretimed signal control (B1) and independent RL-based control agents (B2), i.e. with no coordination. The results show that network-wide average delay savings range from 32% to 63% relative to B1 and from 7% to 12% relative to B2 under different demand levels and arrival profiles.

A Survey on YouTube Streaming Service

Scipedia content — Mon, 01 Feb 2021 23:34:47 +0100

Established in 2005, YouTube is one of the fastest-growing websites, and has become one of the most accessed sites in the Internet. It has a significant impact on the Internet traffic distribution, but itself is suffering from severe scalability constraints and quality of service. Understanding the features of YouTube is thus crucial to network traffic engineering and to sustainable development of this new generation of services. In this survey, we first present an overview of previous works and analysis on YouTube with a particular attention on Quality of Experience. We then describe how the increased availability of meta-data in Web 2.0 (e.g., popularity distribution of video clips) could be effectively exploited to improve the performance and scalability of YouTube. In particular, we study the benefit gained by local caching along with prefetching in terms of reducing the client access time and start up delay in watching video.

A cooperative scheme to aggregate spatio-temporal events in VANETs

Scipedia content — Mon, 01 Feb 2021 23:32:09 +0100

International audience; Today, thanks to vehicular networks, drivers may receive useful information produced or relayed by neighboring sensors or vehicles (e.g., the location of an available parking space, of a traffic congestion, etc.). In this paper, we address the problem of providing assistance to the driver when no recent information has been received on his/her vehicle. Therefore, we present a cooperative scheme to aggregate, store and exchange these events in order to have an history of past events. This scheme is based on a dedicated spatio-temporal aggregation structure using Flajolet-Martin sketches and deployed on each vehicle. Contrary to existing approaches considering data aggregation in vehicular networks, our main goal here is not to save network bandwidth but rather to extract useful knowledge from previous observations. In this paper, we present our aggregation data structure, the associated exchange protocol and a set of experiments showing the effectiveness of our proposal.

Bidirectional multilevel converter for electric vehicles

Scipedia content — Mon, 01 Feb 2021 23:28:07 +0100

In this paper is presented an H-Bridge Multilevel Converter topology for Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs). The topology of the presented multilevel converter allows the interface between the batteries, the electric motor of the vehicle, and the electrical power grid. Thereby, taking into account that the proposed multilevel converter requires the use of isolated voltage sources, the interface between the batteries and the multilevel converter is evaluated regarding the converter operation as a Battery Management System (BMS), controlling the charging and discharging processes. The interface between the multilevel converter and the electrical power grid is described considering a bidirectional operation. These modes of operation occur during the batteries charging process, denominated as Grid-to-Vehicle (G2V), and during the operation as Vehicle-to-Grid (V2G), that consists in delivering back to the electrical power grid a small amount of the energy stored in the batteries, in accordance with the electrical grid requirements and with the vehicle driver accordance. In both modes of operation, the waveform of the AC current of the electrical power grid is kept sinusoidal with unitary power factor, contributing to maintain a good level of power quality. FEDER Funds - Operational Programme for Competitiveness Factors (COMPETE) Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EEA-EEL/104569/2008, MITPT/ EDAM-SMS/0030/2008

Wind Information Requirements to Support Four Dimensional Trajectory-Based Operations

Scipedia content — Mon, 01 Feb 2021 23:19:53 +0100

†‡ § ** Accurate wind information is required to support some of the key applications envisioned for future air traffic concepts. A Wind Information Analysis Framework is described to assess wind information needs for different applications. The framework is applied in a Four-Dimensional Trajectory Based Operations (4D-TBO) application using simplified versions of the framework’s elements to demonstrate its utility. Realistic ranges of wind information accuracy limitations in terms of wind forecast and Flight Management System wind representation errors are studied. Their impacts on 4D-TBO performance in terms of Required Time of Arrival compliance and fuel burn are presented. Interpretations of the findings to determine wind information requirements are provided.

An Operational Model for the Prediction of Jet Blast

Scipedia content — Mon, 01 Feb 2021 23:00:15 +0100

This paper presents an operational model for the prediction of jet blast. The model was developed based upon three modules including a jet exhaust model, jet centerline decay model and aircraft motion model. The final analysis was compared with data acquired during a jet blast study conducted by the Volpe Center in 1999. The current analysis closely matched the data from the 1999 test. The analysis was then used to predict the jet blast evolution from aircraft that have been introduced since 1999, including the Boeing 777300ER. The result of this analysis is a tool that can be used to help provide insight to operating procedure designs where jet blast concerns may arise.

Radar simulation in SiVIC platform for transportation issues. Antenna and propagation channel modelling

Scipedia content — Mon, 01 Feb 2021 22:52:16 +0100

International audience; This paper proposes a new radar sensor modelling for Advanced Driver Assistance Systems (ADAS) prototyping. The model is embedded on the SiVIC platform (Simulator for Vehicle, Infrastructure and Sensors). Lots of simulators already exist for this issue, but none is designed to address the objectives of real-time computation, highly sampled signal generation. And few simulators offer the ability to be integrated in a dynamic platform for the ADAS prototyping. In this paper, several radar technologies will be presented. Then, a radar designed especially for automotive domain will be described exploring each subparts, radar antenna andi.e. propagation channel. Such as the generic model, hypothesis done on electromagnetic waves and environmental objects modelling will also be provided. A first model of simple duplex radar with Frequency Shift Keying (FSK) modulation is implemented and shown as illustration for the defined architecture. Finally, in order to optimize the duration for signal generation, several software architecture solution will be proposed.

Joint Probabilistic Data Association fusion approach for pedestrian detection

Scipedia content — Mon, 01 Feb 2021 22:43:36 +0100

Fusion is becoming a classic topic in Intelligent Transport System (ITS) society. The lack of trustworthy sensors requires the combination of several devices to provide reliable detections. In this paper a novel approach, that takes advantage of the Joint Probabilistic Data Association technique (JPDA) for data association, is presented. The approach uses one of the most powerful techniques of Multiple Target Tracking theory and adapts it to fulfill the strong requirements of road safety applications. The different test performed proved that a powerful association technique can enhance the capacity of Advance Driver Assistance Systems. Two main sensors are used for pedestrian detection: laser scanner and computer vision. Furthermore, the approach takes advantage of the availability of other information sources i.e. context information and online information (GPS). The detections are fused using JPDA, enhancing the capacities of classical pedestrian detection systems, mainly based in visual information. The test performed also showed that JPDA improved the results offered by other data association techniques, e.g. Global Nearest Neighbors. This work was supported by the Spanish Government through the Cicyt projects (GRANT TRA2010-20225-C03- 01) and (GRANT TRA2011-29454-C03-02). CAM through SEGAUTO-II ( S2009/DPI-1509) .

Determination and visualization of uncertainties in 4D-trajectory prediction

Scipedia content — Mon, 01 Feb 2021 22:31:16 +0100

Future air traffic management relies on trajectory forecasting for higher safety, efficiency and environmental friendliness. The quality of trajectory predictions is subject to errors from a variety of sources. These errors in parameters cause inaccuracies in the calculations of the flight trajectories. Therefore the implementation of the future trajectory-based air traffic management requires decision support tools as well as reporting tools to analyze and predict uncertainties in actual flight paths. The Institute of Flight Guidance of the German Aerospace Center (DLR) is one of the leading establishments in the field of air traffic management and conducts research with focus on trajectories based on simulation systems. These simulations are strongly focused on generating scientific data which are evaluated subsequent to the campaign. To be able to evaluate the simulations, we developed a concept for the calculation and visualization of the trajectory prediction uncertainty. The concept is implemented as a component into DLR’s evaluation environment “Extensible Workflow Management for Simulations'' (EWMS) and validated using simulation scenarios. The most important factors for trajectory prediction, which are analyzed for the theoretical concept, are meteorological parameters (wind, temperature), aircraft performance (weight, speed) and navigation performance. Finally, the study applies error analysis to a sample collection of over 2,000 flights under various environmental conditions. The uncertainty of an aircraft position can be described in terms of temporal or spatial metrics by three-dimensional ellipsoids. For the processing in computer scientific systems the error data are classified and the possibilities of visualization in diagrams and geo systems are evaluated. For the representation of scalar errors charts generated by JFreeChart-Tool are suitable. NASA World Wind is used for the geographical visualization of trajectories and their errors. The concept implemented in EWMS enables the user to load fast-time simulation results from the TrafficSim-tool, calculate and compare trajectory uncertainties, and to visualize the results in diagrams as well as in the 3D NASA World Wind environment. The developed calculation and visualization routines provide the ability to analyze trajectory-based air traffic management concepts, as well as support decision-making in air traffic control.

The potential of electric and non-electric bicycles to reduce energy consumption and emissions in private transport

Scipedia content — Mon, 01 Feb 2021 22:23:15 +0100

Electric vehicles are widely considered as an important future option to reduce green house gas emissions from car traffic due to their efficient propulsion technology and the possibility to be charged from renewable energy sources. However, replacing car trips by bicycle trips in principle allows a strong reduction of fossil fuel demand in private transport even with currently available technologies. Two factors of current development increase the likelihood of this option: the introduction of electric bicycles and the construction of bicycle fast lanes. The former have already reached significant sales shares in different European countries and the latter are currently being introduced as special bicycle "motor ways" in different regions of Europe. Both increase the likelihood of slightly longer trips to be performed by bicycle. However, the real potential for CO2 mitigation and possible substitution rates (substitute car trips by bicycle trips) are not properly understood yet. Here, we combine different statistical sources to estimate the potential of increased bicycle driving and the possible reduction of energy use in private transport and green house gas emissions. Using a large data set of German vehicle usage we analyse their driving behaviour in terms of the distribution of trip lengths, working trips and their weather dependence. Our analysis shows that electric and non-electric two-wheelers have the potential to mitigate traffic and emissions in densely populated regions.

Study of Lateral Buckling of Submarine Pipeline

Scipedia content — Mon, 01 Feb 2021 21:55:37 +0100

The upheaval buckling of marine pipelines caused by the temperature stress is one of the main failure modes of pipelines. When a pipeline is operated at high internal pressure and temperature, it will attempt to expand and contract for differential temperature changes. Normally the line is not free to move because of the plane strain constraints in the longitudinal direction and soil friction effects. For positive differential temperature it will be subjected to an axial compressive load and when this load reaches some critical value, the pipe may experience vertical (upheaval buckling) or lateral (snaking buckling) movements that can jeopardize the structural integrity of the pipeline. In these circumstances, an evaluation of the pipeline behavior should be performed in order to ensure the pipeline structural integrity during operation in such demanding loading conditions. Performing such analysis, the correct mitigation measures for thermal buckling can be taken into account either by acceptance of bar buckling but preventing the development of excessive bending moment, or by preventing any occurrence of bending.