Scipedia: Documents published in 2011

Predictive Models of Duration of Ground Delay Programs in New York Area Airports

Scipedia content — Tue, 02 Feb 2021 05:46:12 +0100

Initially planned GDP duration often turns out to be an underestimate or an overestimate of the actual GDP duration. This, in turn, results in avoidable airborne or ground delays in the system. Therefore, better models of actual duration have the potential of reducing delays in the system. The overall objective of this study is to develop such models based on logs of GDPs. In a previous report, we described descriptive models of Ground Delay Programs. These models were defined in terms of initial planned duration and in terms of categorical variables. These descriptive models are good at characterizing the historical errors in planned GDP durations. This paper focuses on developing predictive models of GDP duration. Traffic Management Initiatives (TMI) are logged by Air Traffic Control facilities with The National Traffic Management Log (NTML) which is a single system for automated recoding, coordination, and distribution of relevant information about TMIs throughout the National Airspace System. (Brickman, 2004 Yuditsky, 2007) We use 2008-2009 GDP data from the NTML database for the study reported in this paper. NTML information about a GDP includes the initial specification, possibly one or more revisions, and the cancellation. In the next section, we describe general characteristics of Ground Delay Programs. In the third section, we develop models of actual duration. In the fourth section, we compare predictive performance of these models. The final section is a conclusion.

Real-time data driven arterial simulation for performance measures estimation

Scipedia content — Tue, 02 Feb 2021 05:25:01 +0100

Transportation professionals are increasingly exploring multi-pronged solutions to alleviate traffic congestion. Real-time information systems for travelers and facility managers are one approach that has been the focus of many recent efforts. Real-time performance information can facilitate more efficient roadway usage and operations. Toward this end, a dynamic data driven simulation based system for estimating and predicting performance measures along arterial streets in real-time is described that uses microscopic traffic simulations, driven by point sensor data. Current practices of real-time estimation of roadway performance measures are reviewed. The proposed real-time data driven arterial simulation methodology to estimate performance measures along arterials is presented as well as preliminary field results that provide evidence to validate this approach.

Using an equilibrium model to forecast airline behavior in response to economic or regulatory changes

Scipedia content — Tue, 02 Feb 2021 05:14:07 +0100

Government and industry are exploring approaches, such as technology (e.g. SESAR/NextGen) and market-based methods, to address the pervasive delays in the air transportation system. Resistance to some of the proposed market-based strategies are based on uncertainties of the societal and economic outcomes; specifically, there is a concern that fewer markets might be served, that service within existing markets might be decreased, that airfares might rise significantly and that airline profitability will suffer. This paper describes a comparison of the behavior of the air transportation system (e.g. markets served, airfares, delays, load factors, aircraft size) during the recent run-up in fuel prices at capacity-limited New York airports and non-slot controlled San Francisco and Philadelphia airports. The results of the modeled airline behavior shows: i. Airfares change in proportion to changes in fuel prices. ii. Flights per day and markets served change in proportion to changes in airport capacity limits. iii. Average aircraft size changes in proportion to changes in airfares, number of markets served, and number of flights per day. iv. Airline profitability changes in proportion to flights per day, airfares, and average aircraft size. The implications of these results are discussed in this paper.

Water Main Burst Event Detection and Localization

Scipedia content — Tue, 02 Feb 2021 04:54:39 +0100

In this paper we present a technique for detecting and locating burst events in pipelines. The proposed method uses wavelet analysis of the high-rate pressure data to detect pipe burst events. Multiscale wavelet analysis of the pressure signal will be shown to be robust to impulsive noise encountered in the physical phenomena under observation. The wavelet coefficients also allow us to obtain additional information about the nature of the signal feature detected, which can used for further feature classification. A local search method is also proposed to accurately determine the arrival time of the pressure front associated with the burst event. The detection performance of these algorithms is verified through leak-off experiments performed on the WaterWiSe@SG test bed deployed on the water distribution system in Singapore. We also propose a graph-based search algorithm which uses the arrival times of the pressure front at different locations within the water distribution system to determine the actual location of the pipe burst event.

Etude exploratoire du stylo électronique pour le contrôle aérien

Scipedia content — Tue, 02 Feb 2021 04:43:44 +0100

International audience; Current environment used by air traffic controllers mixes digital visualizations (radar screen), and tangible systems with paper strip. Despite the fact that paper strip are robust, flexible and complementary to the radar screen, authorities decided to abandon it in the profit of digital strip. The main issue of paper strip is that the system does not have access to the information written on it. In this paper, we studied an alternative solution with hybrids Anoto pens with contiuous streaming. We first retrieved important tasks performed by air traffic controller, second, we investigated to find out efficient interaction paradigm for their activity. Finally, we developed and assessed an operational prototype with new functionalities. This suggests that it is possible to retain advantages of existing paper strip while informing informatics systems and improving interaction.

Recent Advances in Pipe Wall Assessment Technology

Scipedia content — Tue, 02 Feb 2021 04:37:45 +0100

Most of North America's oldest water mains are constructed of ferrous material, in particular cast iron, ductile iron, and steel. As utilities rarely have funds to replace all of these pipelines at the end of their design life, utilities are forced to carefully target their replacement and rehabilitation budgets. Critical for this targeting of funds is the availability of accurate knowledge of the actual pipeline conditions, in particular assessing the condition of the pipe wall and its impact on the remaining useful life of the pipeline. With this clear and impending need, a variety of technologies are becoming available for pipe wall assessment. This paper details developments and advances over the past two years in several technologies for pipe wall assessment. The results provided by each technology are outlined, as well as how these results can be used to assess progression along the failure paths of various types of pipelines. The tools are grouped in a systematic way, illustrating how they fit into three fundamental philosophies towards condition assessment. Examples of their application are provided for tools advanced beyond the R&D phase. Abstract ID 112 1. FAILURE MODES OF METALLIC MAINS Pipes fail when some portion of the pipe is no longer strong enough to withstand the stress applied to it. This can happen when unexpected stress is placed on the pipe, or when the pipe loses enough strength to be overcome by the planned stress of normal operation. In most cases, it is a combination of the two: an unexpected stress, such as a water hammer, causes a failure at a point that has been weakened by one or more factors, such as cracking or corrosion. (Makar et al, 2001) Different types of pipe have various mechanisms of failure, and hence different failure rates. Cast iron pipes are by far the most prone to failure. Cast iron pipes corrode, are brittle, are prone to cracking, and generally employ bell and spigot joints that can lose their sealing integrity. Many older North American cities contain cast iron pipe installed in the 1800's, when methods of construction were not uniform and formal quality control (inspection) and pipeline standards did not exist. For example,

CloG: A pipeline for closing gaps in a draft assembly using short reads

Scipedia content — Tue, 02 Feb 2021 04:36:31 +0100

Closing of gaps in draft assemblies using Next Generation Sequencing (NGS) data is becoming increasingly important. In this paper we present CloG, a software pipeline that uses NGS data to close gaps in draft assemblies. Firstly, CloG uses the VELVET assembler to generate a hybrid assembly from a mixture of reads: short reads from the NGS data and the original draft assembly (treated as long reads). It then closes gaps between adjacent contigs by reconciling (i.e., “stitching”) the two assemblies. By exploiting the strengths of both hybrid assembly and stitching reassembly, CloG is able to outperform its contemporaries in closing gaps in the draft assembly of the bacterium Burkholderia dolosa.

Towards Rain Detection through use of In-Vehicle Multipurpose Cameras

Scipedia content — Tue, 02 Feb 2021 04:21:38 +0100

dvanced Driver Assistance Systems (ADAS) based on video camera tends to be generalized in today's automotive. However, if most of these systems perform nicely in good weather conditions, they perform very poorly under adverse weather particularly under rain. We present a novel approach that aims at detecting raindrops on a car windshield using only images from an in-vehicle camera. Based on the photometric properties of raindrops, the algorithm relies on image processing technics to highlight raindrops. Its results can be further used for image restoration and vision enhancement and hence it is a valuable tool for ADAS.

Lateral control assistance and driver behavior in emergency situations

Scipedia content — Tue, 02 Feb 2021 04:19:04 +0100

International audience; Advanced Driver Assistance Systems (ADAS) are designed to help drivers improve driving safety. However, automation modifying the way drivers interact with their vehicle, it is important to avoid negative safety impacts. In particular, the change in drivers’ behavior introduced by ADAS in situations they are not designed for, should be carefully examined. We carried out an experiment on a driving simulator to study drivers’ reaction in an obstacle avoidance situation, when using a lateral control assistance system. A detailed analysis of the avoidance maneuver is presented. Results show that assisted and non-assisted drivers equally succeeded in avoiding the obstacle. However, further analyses tend to show an influence of the assistance system on drivers’ first reaction.

A Route-Based Queuing Network Model for Air Traffic Flow Contingency Management

Scipedia content — Tue, 02 Feb 2021 04:13:24 +0100

Ongoing research is currently focused on the need to improve the strategic traffic flow management decision making processes. The research effort in this paper is part of a greater research initiative aimed at developing quantitative analysis and design capabilities for flow contingency management, which include the design of queuing network models. This paper proposes to use the concept of route assignment for managing aggregate air traffic demand and evaluating flow contingency plans generated by human decision makers. To determine how strategic traffic controls are captured and the computational requirements associated, a simulation experiment is conducted with realistic demand data and weather impact scenarios. System-wide performance results on a realistic plan of strategic control are analyzed, and the computational requirements of arc-based and route-based modeling choices will also be discussed.

A focus on operational feasibility and potential gain

Scipedia content — Tue, 02 Feb 2021 04:05:33 +0100

Formation flying is introduced as a new and innovative air transportation system for long-haul commercial flight. With this paper the operational feasibility of formation flying is addressed, both from a market demand and economic, as well as an air traffic control perspective. Preliminary results of a case study indicate that operating a newly designed aircraft that is optimized for formation flying could cut the fuel consumption over long-haul flights in half compared to current state-of-the-art aircraft. Therefore, this air transportation system proves to be a possible solution to the impending regulations and fines regarding the reduction of CO2 emissions in aviation.

The Transport Integration Act 2010: driving integrated and sustainable transport outcomes through legislation

Scipedia content — Tue, 02 Feb 2021 03:59:18 +0100

This paper describes how the Transport Integration Act 2010 (TIA) is Victoria, Australia’s key piece of legislation in the area of transport. The Act provides an example of the use of aspirational legislation to reflect the broad policy aims of the government for integrated and sustainable transport. This paper traces the policy development process for aspirational legislation in Victoria that has taken place as part of a broader review of transport legislation. The Act locates the development of a policy framework for integrated and sustainable transport in Victoria within global and national debates regarding sustainable development. This has resulted in the inclusion of a vision, set of objectives and decision making principles for transport in the TIA reflecting an integration and sustainability policy framework. It is necessary to continue work on implementing this policy framework across transport and land use planning agencies in order to ensure that the TIA is successful in achieving its policy outcomes.

Improving roadside surveys for a better knowledge of road freight transport

Scipedia content — Tue, 02 Feb 2021 03:32:33 +0100

International audience; Purpose : The focus of this paper is to enhance our observation and knowledge of interurban road freight transport. It explores some possibilities for improving roadside freight surveys, usually used to gather origin-destination data. Methodology : To achieve this, new questions are added to a standard roadside survey form, and the enhanced survey form is tested through two surveys. The new questions relate to currently unobserved variables: the vehicle volume occupied by freight; the method of organisation (double crew, relays) used by the carriers; the existence of speci c logistical imperatives; and drivers' compulsory breaks. Results : The questions on volume constraint and carrier organisation prove to be the most informative. These two questions are thus two promising areas for improvement in roadside freight surveys. The questions about speci c logistical imperatives and driver breaks prove less fruitful. Conclusion : The paper concludes that it is possible, through minor modi cations in data collection protocols, to signi cantly enhance observation quality in road freight transport activity.

Pipeline Engineering in the Ground: The Impact of Ground Conditions on Pipeline Condition and Maintenance Operations

Scipedia content — Tue, 02 Feb 2021 03:31:51 +0100

The ground in which utility service pipelines are buried inevitably controls, to a large degree, the structural performance and progressive deterioration of the pipelines themselves. In a parallel programme of research to the UK Mapping the Underworld (MTU) project, a study of the fundamental properties of the ground, and how they change with the seasons and local physical and chemical contexts, is being conducted at the University of Birmingham, UK. While the results of this study feed into both the operational protocols for the MTU multi-sensor location device and the associated knowledge based system (KBS) that is being created to aid its deployment (both topics being the subjects of separate papers to this conference), the suite of complementary research projects on the ground and its properties provide valuable insights to the pipeline engineer. Geophysics is being used by the research team to explore the state of the ground with the aim of highlighting areas of concern for the structural health of pipelines buried in the ground. Studies of cast iron pipeline corrosion mechanisms have focussed on the changes that the reaction products cause to the surrounding soils, with a particular emphasis on clay soils, and one interesting finding is that these clay-iron reaction products can make the pipelines ‘invisible’ to standard geophysical location devices. Moreover there are other features in the ground that are being targeted (voids, ground wetting and softening due to leakage, ground weakening due to progressive erosion), and these features effectively make the ground more or less ‘visible’ to geophysical technologies. Alongside this work, bespoke tests have been developed for use on site to ‘calibrate’ the geophysics, thereby enhancing the signatures of the features. This paper introduces these parallel research projects and draws out the important findings for pipeline engineers charged with establishing the condition of existing buried assets.

Human-centered challenges and contributions for the implementation of automated driving

Scipedia content — Tue, 02 Feb 2021 03:04:33 +0100

utomated driving is expected to increase safety and efficiency of road transport. With regard to the implementation of automated driving, we observed that those aspects which need to be further developed especially relate to human capabilities. Based on this observation and the understanding that automation will most likely be applied in terms of partially automated driving, we distinguished 2 major challenges for the implementation of partially automated driving: (1) Defining appropriate levels of automation, and; (2) Developing appropriate transitions between manual control and automation. The Assisted Driver Model has provided a framework for the first challenge, because this model recommends levels of automation dependent on traffic situations. To conclude, this research also provided brief directions on the second challenge, i.e. solutions how to accommodate drivers with partially automation

Accuracy of Dynamic and Acoustic Analysis of Lightweight Panel Structures:a comparison of ABAQUS and ANSYS

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

Currently there is an increasing focus on the transmission of low frequency sound in buildings, as sources such as road and air traffic or even home theatre subwoofers become part of everyday life for many people. Hence, development of efficient and accurate methods for prediction of sound in such buildings is important. In the lowfrequency range, prediction of sound and vibration in building structures may be achieved by finite-element analysis (FEA). The aim of this paper is to compare the two commercial codes ABAQUS and ANSYS for FEA of an acoustic-structural coupling in a timber lightweight panel structure. For this purpose, modal analyses are carried out employing a fully coupled model of sound waves within an acoustic medium and vibrations in the structural part. The study concerns the frequency range 50–250 Hz.

Estimation of maximum-likelihood discrete-choice models of the runway configuration selection process

Scipedia content — Tue, 02 Feb 2021 02:40:42 +0100

The runway configuration is the subset of the runways at an airport that are used for arrivals and departures at any time. Many factors, including weather (wind and visibility), expected arrival and departure demand, environmental considerations such as noise abatement procedures, and coordination of flows with neighboring airports, govern the choice of runway configuration. This paper develops a statistical model to characterize this process using empirical observations. In particular, we demonstrate how a maximum-likelihood discrete-choice model of the runway configuration process can be estimated using aggregate traffic count and other archived data at an airport, that are available over 15 minute intervals. We show that the estimated discrete-choice model not only identifies the influence of various factors in decision-making, but also provides significantly better predictions of runway configuration changes than a baseline model based on the frequency of occurrence of different configurations. The approach is illustrated using data from Newark (EWR) and LaGuardia (LGA) airports.

Document type: Conference object

Modeling tourist's mode choice behavior under parking and cordon charge policies

Scipedia content — Tue, 02 Feb 2021 02:36:40 +0100

Traffic congestion is a perennial problem at seasonal tourist destinations throughout the world. Meanwhile, understanding the mode choices of tourist's traveler will help to identify effective solutions. This analysis contributes to that effort by characterizing the mode preferences of tourists under parking and cordon polices in central business district (CBD) of Mashhad city. With respect to the research methodology, this research employs econometric model, discrete choice model. Using a stated preference survey of visitors, the results presented that travel time, parking fare, cordon cost, education levels and vehicle price type are characteristics in Mashhad city that determine tourist's modal choice and influence the modal shift from congestion pricing in central business area. In addition, the finding shows that congestion pricing has more effective response than the parking strategy.

Real-Time Leak Isolation based on State Estimation in a Plastic Pipeline

Scipedia content — Tue, 02 Feb 2021 02:10:54 +0100

International audience; A Leak Detection and Isolation (LDI) algorithm based on a State Estimation Observer is designed and tested in real-time to locate a water-leak on a plastic pipeline prototype. In order to tackle the problem of friction variations in such a pipeline, the explicit so-called Swamee-Jain equation is implanted for the friction, instead of a constant parameter as in other studies. The observer is then designed as an Extended Kalman filter on the basis of a discretized model both in time and in space. The space discretization is nonuniform depending on the unknown leak location, and the time variable is discretized with the Heun's method. The approach assumes only flow and pressure sensors at the ends of the duct, and experimental results with data obtained from the pipeline prototype are presented to assess the method efficiency.

Not Planning a Sustainable Transport System - Swedish Case Studies

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

The overall objective of the Swedish transport policy is to ensure the economically efficient and sustainable provision of transport services for people and business throughout the country. More specifically the transport sector shall contribute to the achievement of environmental quality objectives where the development of the transport system plays an important role in the achievement of the objectives. The aim of this study is to analyse if current transport planning supports this policy. This is done by analyzing two recent cases: the national infrastructure plan 2010-2021 and the planning of Bypass Stockholm, a major road investment. Our results show that the plans are in conflict with several of the environmental quality objectives. Another interesting aspect of the planning processes is that the long-term climate goals are not included in the planning processes, neither as a clear goal nor as factor which will influence the future transport system. In this way the long-term sustainability aspects are not present in the planning. We conclude that the two cases do not contribute to a sustainable transport system. Thus, several changes must be made in the processes, including putting up clear targets for emissions.

Implementation of a transmission line model for fast simulation of fluid flow dynamics

Scipedia content — Tue, 02 Feb 2021 02:07:36 +0100

n implementation of a lumped and 1-dimensional pipeline model for simulation of fast pressure and flow transients such as water-hammer effects is presented. It is an extension of the classical Transmission Line Model (TLM), a transfer matrix representation of a pipeline, relating pressure and volume flow rates at the extremities of a pipeline. The proposed model has extended previous work in different aspects. The extensions were developed for the detailed operational investigation of a pipeline for the transport of carbon dioxide from a carbon capture plant to a suitable location for the geological storage of supercritical, dense phase carbon dioxide. A lumped temperature model, derived as the TLM model by integrating the distributed dynamics, has been added to describe the effect of heat losses in long pipelines. A dynamic friction model that is explicit in the medium and pipeline characterisitcs has also been included. Finally, it is shown that, with simple adjustments, the model can reasonably well describe the pressure dynamics in turbulent flow conditions. Some simulations have been carried out to compare the performance of the proposed model to the one from the Modelica Standard Library, and the results were also compared to measurement results from the literature. The resulting model has become useful for a wide variety of engineering applications: pipelines for gas and oil, district heating networks, water distribution networks, wastewater systems, hydro power plants and more. In the lumped, constant temperature version, there are no discretization artifacts, and even in the discretized version taking into account spatial and temporal changes in temperature, discretization artifacts are much smaller than for the standard finite volume model. Moreover, the short simulation times make the model suitable for real-time applications.

Evaluation of Seven Flexible Linings to Determine Suitability As an Alternative to Mortar Lining

Scipedia content — Tue, 02 Feb 2021 01:47:07 +0100

Southern Nevada gets nearly 90 percent of its water supply from the Colorado River which is currently facing the worst drought on record. To ensure a more reliable long term water supply for the Las Vegas Valley, the Southern Nevada Water Authority (SNWA, Authority) is planning to develop water resources in east-central Nevada. The Groundwater Development (GWD) Project is proposed to ultimately consist of a pipeline and power conveyance system and well fields. The main pipeline system, made up of welded steel pipe ranging in size from 66-inches to 96-inches in diameter, will transmit groundwater from well fields to be developed in Lincoln and White Pines Counties, Nevada over 200 miles into Clark County, Nevada. SNWA enlisted the preliminary design services of HDR Engineering to perform system hydraulic analysis and facility definition of the main pipeline. The preliminary design effort included evaluation of various options for pipe procurement. Any option considered would likely result in the pipe being stored for extended periods of time. The duration and harsh climate where the pipe would be stored caused concern that that the integrity of a mortar lining could be compromised. In addition, SNWA experience caused concern that, because of the water chemistry, leaching of alkalinity from the mortar lining could necessitate extensive flushing of the line. Lastly, due to the magnitude of the project, the use of flexible linings had the potential to reduce the tonnage of steel and thus reduce the overall project cost. These factors contributed to convincing the project team that alternate lining materials should be considered. Investigations showed that flexible linings, specifically polyurethane linings, were gaining more acceptance as an alternative to cement mortar linings. However, experience with flexible linings in water pipelines is limited. Epoxy systems were added to the evaluation after considering that recent developments in the formulation of epoxy systems have resulted in quicker set times. Epoxies, as a family of products, have been available longer than polyurethane systems.

Latency inflation with MPLS-based traffic engineering

Scipedia content — Tue, 02 Feb 2021 01:36:27 +0100

While MPLS has been extensively deployed in recent years, little is known about its behavior in practice. We examine the performance of MPLS in Microsoft's online service network (MSN), a well-provisioned multi-continent production network connecting tens of data centers. Using detailed traces collected over a 2-month period, we find that many paths experience significantly inflated latencies. We correlate occurrences of latency inflation with routers, links, and DC-pairs. This analysis sheds light on the causes of latency inflation and suggests several avenues for alleviating the problem.

Metro line implementation in a European city

Scipedia content — Tue, 02 Feb 2021 01:24:07 +0100

This paper describes how the train, which is the earliest form of mass transport, with technological evolution has become far less of a polluter than other forms of transportation. Green and sustainable transportation is essential for every region for social and economic growth. This paper analyzes specificities of a European urban rail network. Offer/demand disequilibrium is identified and potential solutions are presented in the paper. Because the geographical area is vast and data is dissipated, it is essential to select the most accurate information available. A first step is to determine disequilibrium between existing capacity and current rail transport demand. Existing capacity is the total daily number of passengers transported in each rail network zone. Current transport demand is the total number of citizens that need rail transport for daily displacements in each zone. Current rail transport demand estimation is based on regression analysis tools applied to Local Transport Authority annual mobility reports. Demand is also estimated for new line entrance in service year, plus ten, twenty and thirty years. These long term previsions are essential in analyzing the offer/demand evolution process with reversed impacts in land-use politics. Different transport options are going to be analyzed and their economic and technical viability will be considered to support a final solution. This paper will start with a city and an existing transport network briefing. This will be followed in the paper by a service characterization. Existing capacity is determined to establish a workable level and current transport demand and its characteristics will precede demand variation. The main factors influencing these variables are presented and disequilibrium and potential solutions are evaluated before the paper concludes with an economic analysis.

Transportation and sustainable development in a mid-size French city, Dijon

Scipedia content — Tue, 02 Feb 2021 01:21:57 +0100

International audience

Stability analysis of transportation networks with multiscale driver decisions

Scipedia content — Tue, 02 Feb 2021 01:20:17 +0100

Stability of Wardrop equilibria is analyzed for dynamical transportation networks in which the drivers' route choices are influenced by information at multiple temporal and spatial scales. The considered model involves a continuum of indistinguishable drivers commuting between a common origin/destination pair in an acyclic transportation network. The drivers' route choices are affected by their, relatively infrequent, perturbed best responses to global information about the current network congestion levels, as well as their instantaneous local observation of the immediate surroundings as they transit through the network. A novel model is proposed for the drivers' route choice behavior, exhibiting local consistency with their preference toward globally less congested paths as well as myopic decisions in favor of locally less congested paths. The simultaneous evolution of the traffic congestion on the network and of the aggregate path preference is modeled by a system of coupled ordinary differential equations. The main result shows that, if the frequency of updates of path preferences is sufficiently small as compared to the frequency of the traffic flow dynamics, then the state of the transportation network ultimately approaches a neighborhood of the Wardrop equilibrium. The presented results may be read as a further evidence in support of Wardrop's postulate of equilibrium, showing robustness of it with respect to non-persistent perturbations. The proposed analysis combines techniques from singular perturbation theory, evolutionary game theory, and cooperative dynamical systems.

Comment: 21 pages, 2 figures, submitted

MODELLING ENVIRONMENTAL INFLUENCE ON THE PIPELINES INTEGRITY

Scipedia content — Tue, 02 Feb 2021 00:12:37 +0100

Environmental impact assessment based on a potential oil spill scenario: Eastern Black Sea coastal zone, Turkey

Scipedia content — Mon, 01 Feb 2021 23:59:36 +0100

The coastal fishery made in the Eastern Black Sea coastal area satisfies the country’s major demand for fish and seafood. The area has also attracted attention with the increasing international oil and gas exploration activities carried on recently. Large capacity tankers pass through this sea area to carry crude oil and petrochemical products while existing and planned hydrocarbon transportation pipelines increase the cargo traffic as well. Therefore the new environmental risks are threatening this region’s ecosystem due to the potential events such as tanker accidents, well explosions or pipeline leaks. In this study, the off-shore oil spill scenario is modeled for the Eastern Black Sea area. Potential Incident Simulation Control and Evaluation System (PISCES 2) is used to simulate the spreading of the spilled oil. The following factors are taken into consideration in the mathematical model: 1) environmental parameters: coastline, field of currents, weather, wave height and water density, 2) physical properties of spilled oil: specific gravity, surface tension, viscosity, distillation curve and emulsification characteristics, 3) properties of spill sources. Results of the oil spill scenario modeling shows extremely negative environmental impact of the potential oil spill accident on the coastal zone of the Eastern Black Sea.

Inferring a network congestion map with zero traffic overhead

Scipedia content — Mon, 01 Feb 2021 23:57:30 +0100

This paper proposes a purely passive method for inferring a congestion map of a network. The congestion map is computed using the congestion markings carried in existing traffic, and is continuously updated as traffic is received. Consequently, congestion changes can be tracked in a real-time fashion with zero traffic overhead. Unlike active congestion reporting methods, our novel passive method is more robust during periods of congestion because there are no congestion report messages that could be lost and existing congestion is never aggravated. Our solution has several applications ranging from informing IP fast re-route algorithms and traffic engineering schemes to assisting in inter-domain path selection.

Downtown Parking and Traffic Congestion: A Diagrammatic Exposition

Scipedia content — Mon, 01 Feb 2021 23:49:21 +0100

Through an extended numerical example, this paper develops a diagrammatic analysis of steady-state parking and traffic congestion in an isotropic downtown and provides systematic policy analysis. Unlike our previous work, the model incorporates curbside parking, garage parking, and price-sensitive travel demand in a unified setting. We examine the deadweight loss associated with underpriced curbside parking, as well as first- and second-best curbside parking capacities. We also explore the transient dynamics and stability of various downtown traffic equilibria. Keywords: cruising for parking, curbside parking, parking garages, parking policy, traffic congestion JEL Classification: D04; L91; R41; R48

Benefits of Mid-Term Flexible Airspace Management in Presence of Weather

Scipedia content — Mon, 01 Feb 2021 23:45:32 +0100

By examining the relative benefit of reconfigured airspace to the original airspace under the same traffic conditions, this paper assessed Flexible Airspace Management that reconfigures airspace boundaries. Using weather rerouted flight plans, four airspace design methods reconfigured the original airspace design in Kansas City Center. Air traffic simulations with estimated NextGen midterm (2018) airport capacities and traffic demand were performed for the original and each reconfigured airspace design. Analysis showed that within the simulated scenarios, reconfigured airspace demonstrated user benefit by decreasing 68% of the number of flights needing to be delayed or turned away from entering the airspace to maintain balance between traffic demand and capacity. Utilization of available air traffic control resources increased by 8%, demonstrating service provider benefit. Airspace design methods that applied more changes to the original airspace achieved more benefit. However, increased change from the original airspace configuration implied a possible increase in air traffic controller workload during the transition from the original to the reconfigured airspace.

STUDIES DETERMINING THE AGGRESSIVENESS OF WATER IN GEOTECHNICAL PRACTICE

Scipedia content — Mon, 01 Feb 2021 23:35:48 +0100

The aim of this publication is to study realization of aggressiveness of water in engineering geological and geotechnical practice. Determination of water aggressiveness is important for the knowledge of effect of concrete and steel. In the case that water is aggressive to concrete, located in the foundation structure, can be disturbed statics of the building or other malfunctions. Similar problems may occur in the case of steel elements. Moreover, various pipelines are steel pipes, which can be accelerated corrosion damaged. Determination of aggressiveness is thus one of the important goals engineering geological and geotechnical survey.

Optimal time advance in terminal area arrivals: Throughput vs. fuel savings

Scipedia content — Mon, 01 Feb 2021 23:35:03 +0100

The current operational practice in scheduling air traffic arriving at an airport is to adjust flight schedules by delay, i.e. a postponement of an aircraft's arrival at a scheduled location, to manage safely the FAA-mandated separation constraints between aircraft. To meet the observed and forecast growth in traffic demand, however, the practice of time advance (speeding up an aircraft toward a scheduled location) is envisioned for future operations as a practice additional to delay. Time advance has two potential advantages. The first is the capability to minimize, or at least reduce, the excess separation (the distances between pairs of aircraft immediately in-trail) and thereby to increase the throughput of the arriving traffic. The second is to reduce the total traffic delay when the traffic sample is below saturation density. A cost associated with time advance is the fuel expenditure required by an aircraft to speed up. We present an optimal control model of air traffic arriving in a terminal area and solve it using the Pontryagin Maximum Principle. The admissible controls allow time advance, as well as delay, some of the way. The cost function reflects the trade-off between minimizing two competing objectives: excess separation (negatively correlated with throughput) and fuel burn. A number of instances are solved using three different methods, to demonstrate consistency of solutions.

NoC frequency scaling with flexible-pipeline routers

Scipedia content — Mon, 01 Feb 2021 23:20:09 +0100

Voltage and frequency scaling (VFS) for NoC can potentially reduce energy consumption, but the associated increase in latency and degradation in throughput limits its deployment. We propose flexible-pipeline routers that reconfigure pipeline stages upon VFS, so that latency through such routers remains constant. With minimal hardware overhead, the deployment of such routers allows us to reduce network frequency and save network energy, without significant performance degradation. Furthermore, we demonstrate the use of simple performance metrics to determine the optimal operation frequency, considering the energy/performance impact on all aspects of the system — the cores, the caches and the interconnection network.

For Spacious Skies: Self-Separation with "Autonomous Flight Rules" in US Domestic Airspace

Scipedia content — Mon, 01 Feb 2021 22:56:39 +0100

utonomous Flight Rules (AFR) are proposed as a new set of operating regulations in which aircraft navigate on tracks of their choice while self-separating from traffic and weather. AFR would exist alongside Instrument and Visual Flight Rules (IFR and VFR) as one of three available flight options for any appropriately trained and qualified operator with the necessary certified equipment. Historically, ground-based separation services evolved by necessity as aircraft began operating in the clouds and were unable to see each other. Today, technologies for global precision navigation, emerging airborne surveillance, and onboard computing enable traffic conflict management to be fully integrated with navigation procedures onboard the aircraft. By self-separating, aircraft can operate with more flexibility and fewer flight restrictions than are required when using ground-based separation. The AFR concept proposes a practical means in which self-separating aircraft could share the same airspace as IFR and VFR aircraft without disrupting the ongoing processes of Air Traffic Control. The paper discusses the context and motivation for implementing self-separation in US domestic airspace. It presents a historical perspective on separation, the proposed way forward in AFR, the rationale behind mixed operations, and the expected benefits of AFR for the airspace user community.

Advanced Research Strategy for Designing the Car of the Future

Scipedia content — Mon, 01 Feb 2021 22:51:47 +0100

This paper describes a novel concept regarding the method for research and development of future vehicles. It is shown that the traditional rate of progress cannot keep up with the increasingly pressing issues of global warming and social sustainability. A new, holistic approach which takes into account the form, operation and social aspects of the future society is suggested. This approach tries to remove the boundaries between different sections of science and also accelerate the rate and speed of adoption of new technologies into the final, mass-produced vehicle. Such an approach can pave the way for the creation of a vehicle that reaches our goal of zero accidents and zero emissions.

Flight Departure Delay and Rerouting Under Uncertainty In En Route Convective Weather

Scipedia content — Mon, 01 Feb 2021 22:41:49 +0100

Delays caused by uncertainty in weather forecasts can be reduced by improving traffic flow management decisions. This paper presents a methodology for traffic flow management under uncertainty in convective weather forecasts. An algorithm for assigning departure delays and reroutes to aircraft is presented. Departure delay and route assignment are executed at multiple stages, during which, updated weather forecasts and flight schedules are used. At each stage, weather forecasts up to a certain look-ahead time are treated as deterministic and flight scheduling is done to mitigate the impact of weather on fourdimensional flight trajectories. Uncertainty in weather forecasts during departure scheduling results in tactical airborne holding of flights. The amount of airborne holding depends on the accuracy of forecasts as well as the look-ahead time included in the departure scheduling. The weather forecast look-ahead time is varied systematically within the experiments perfomed in this paper to analyze its effect on flight delays. Based on the results, longer look-ahead times cause higher departure delays and additional flying time due to reroutes. However, the amount of airborne holding necessary to prevent weather incursions reduces when the forecast look-ahead times are higher. For the chosen day of traffic and weather, setting the look-ahead time to 90 minutes yields the lowest total delay cost.

Development and application of an evaluation framework for urban traffic management and Intelligent Transport Systems

Scipedia content — Mon, 01 Feb 2021 22:39:32 +0100

The aim of this paper is to present and apply a new evaluation framework for traffic management and Intelligent Transport Systems, to assist urban transport authorities in assessing relevant policies and technologies as to their performance. The principles behind performance measures and indices are outlined, along with a description of theframework development methodology. Two Key Performance Indicators (KPIs) for the topics of mobility and traffic accidents respectively are formulated and operative definitions are presented. Then, the new KPIs are applied to a case study in the city of Paris, involving the introduction of a scheme granting priority to buses at signalised junctions. The results from the before- and after-analysis are reported and interpreted, not only in terms of the case study itself, but most importantly from the standpoint of the applicability of the evaluation framework.

Document type: Conference object

Completing Condition Assessments Using In-Pipe GPR As Pipe Penetrating Radar

Scipedia content — Mon, 01 Feb 2021 22:34:46 +0100

This paper describes the development of Pipe Penetrating Radar (PPR), the underground in-pipe application of GPR, a non-destructive testing method that can detect defects and cavities within and outside mainline diameter ("18 in / 450mm) non-metallic (concrete, PVC, HDPE, etc.) underground pipes. The method uses two or more high frequency GPR antennae carried by a robot into underground pipes. The radar data is transmitted to the surface via fibre optic cable and is recorded together with the output from CCTV (and optionally sonar and laser). Proprietary software analyzes the data and pinpoints defects or cavities within and outside the pipe. Thus the testing can identify existing pipe and pipe bedding symptoms that can be addressed to prevent catastrophic failure due to sinkhole development and can provide useful information about the remaining service life of the pipe. The key innovative aspect is the unique ability to map pipe wall thickness and deterioration including cracks and voids outside the pipe, enabling accurate predictability of needed intervention or the timing of replacement. This reliable non-destructive testing method significantly impacts subsurface infrastructure condition based asset management by supplying previously unattainable measurable conditions.

Evaluation of response characteristics of buried pipelines during earthquakes

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

This paper presents an evaluating method for seismic behaviour of pipelines during earthquakes and studies the response characteristics of them for various conditions of ground displacements and pipelines. The proposed method consists of mainly two analytical methods which are the seismic response analysis of surface ground layers and the pseudo static response analysis of buried pipelines. The seismic response analysis method for surface ground layers is 2-dimensional effective stress analysis based on Biot’s two phase mixture theory and Iai’s constitutive equation. The pipeline analysis is based on a beam theory on an elastic foundation and modified transfer matrix method. Numerical computations are performed for various models with changing conditions of ground and pipes. As a result, axial and lateral response characteristics of pipelines are shown and evaluated by relating with earthquakes, grounds and pipelines conditions.

Prediction of weather impacted airport capacity using ensemble learning

Scipedia content — Mon, 01 Feb 2021 22:15:18 +0100

Ensemble learning with the Bagging Decision Tree (BDT) model was used to assess the impact of weather on airport capacities at selected high-demand airports in the United States. The ensemble bagging decision tree models were developed and validated using the Federal Aviation Administration (FAA) Aviation System Performance Metrics (ASPM) data and weather forecast at these airports. The study examines the performance of BDT, along with traditional single Support Vector Machines (SVM), for airport runway configuration selection and airport arrival rates (AAR) prediction during weather impacts. Testing of these models was accomplished using observed weather, weather forecast, and airport operation information at the chosen airports. The experimental results show that ensemble methods are more accurate than a single SVM classifier. The airport capacity ensemble method presented here can be used as a decision support model that supports air traffic flow management to meet the weather impacted airport capacity in order to reduce costs and increase safety.

Contrast restoration of road images taken in foggy weather

Scipedia content — Mon, 01 Feb 2021 22:05:01 +0100

Driver assistance systems based on camera are strongly disturbed by the presence of foggy weather. The restoration of images, as pre-processing, would improve the performances of such systems. In this paper, we propose a method to restore the image contrast of foggy road scenes combining a physical approach, based on Koschmieders model and a signals approach, based on local histogram equalization. Then we optimize the parameters of our method using a simulated annealing. This method, evaluated on a reference image database, presents a significant improvement compared to other methods and gives consistent results for both homogeneous and inhomogeneous fog.

V2G smart system an intelligent system to the electric vehicle charging problem

Scipedia content — Mon, 01 Feb 2021 21:46:35 +0100

The next big step in the evolution of the automotive industry is the introduction of electric vehicles (EV), however has associated limitations of autonomy and in conjunction with this limitation, extended charging times, very few points of charging and smart electricity grids very embryonic. In this context, is requires a very rigorous planning of daily use of the EV. Thus, this work presents an information system that aims to help the driver in the daily use of the EV in order to deal with the charging problem, minimizing the problem of anxiety to achive the objectives through the continuous monitoring of the autonomy of the vehicle and the timely submission of relevant information related to charging process, also allowing the storage the energy transactions for later analysis and further improvements. Similarly, given the limitations of the electrical distribution network and taking into account N simultaneous charging process a management system is proposed to deal with this problem, in order to limit the total power consumed in each moment. Fundação para a Ciência e a Tecnologia (FCT)

Cooperative Regulation of Emissions Using Plug-in Hybrid Vehicles

Scipedia content — Mon, 01 Feb 2021 21:41:46 +0100

We exploit new types of vehicles, such as Plug-in Hybrid Electric Vehicles (PHEVs), to control transport related emissions in urban environments. By appropriately choosing whether single power-split hybrid vehicles should be operated in fully electric or in fuel mode we regulate where and how much pollution is delivered into the environment, without particular inconvenience to the vehicle owners. Preliminary ideas and simulation results are provided to illustrate the efficacy of the proposed approach.

High-Speed Prediction of Air Traffic for Real-Time Decision Support

Scipedia content — Mon, 01 Feb 2021 21:33:14 +0100

The ability to rapidly generate traffic predictions is expected to be central for implementing next-generation air traffic management functionality, both on the ground and aboard aircraft. While high-end computers can be used for this purpose, emerging capabilities of computational hardware such as Graphics Processing Units, together with Cloud Computing concepts can be exploited to realize substantial acceleration of trajectory computations at a modest cost increment. This paper discusses the development of a computational appliance for rapid prediction of aircraft trajectories that combines efficient algorithm and software design with emerging high performance computing architectures. The research effort accelerates trajectory predictions through software profiling and tuning, and implements computationally intensive functions on high performance computing architectures such as computing clusters, multi-threaded programming on multi-core computers and Graphics Processing Units. The fastest of these implementations uses a Graphics Processing Unit, which can perform a system-wide 24-hour trajectory prediction for 35,000 aircraft in less than 2.5 seconds. When compared with the baseline trajectory prediction software, the present approach provides over two orders of magnitude speedup.

HAsim: FPGA-based high-detail multicore simulation using time-division multiplexing

Scipedia content — Mon, 01 Feb 2021 21:30:34 +0100

In this paper we present the HAsim FPGA-accelerated simulator. HAsim is able to model a shared-memory multicore system including detailed core pipelines, cache hierarchy, and on-chip network, using a single FPGA. We describe the scaling techniques that make this possible, including novel uses of time-multiplexing in the core pipeline and on-chip network. We compare our time-multiplexed approach to a direct implementation, and present a case study that motivates why high-detail simulations should continue to play a role in the architectural exploration process.

Estimating Controller Intervention Probabilities for Optimized Profile Descent Arrivals

Scipedia content — Mon, 01 Feb 2021 21:09:29 +0100

Simulations of arrival traffic at Dallas/Fort-Worth and Denver airports were conducted to evaluate incorporating scheduling and separation constraints into advisories that define continuous descent approaches. The goal was to reduce the number of controller interventions required to ensure flights maintain minimum separation distances of 5 nmi horizontally and 1000 ft vertically. It was shown that simply incorporating arrival meter fix crossing-time constraints into the advisory generation could eliminate over half of the all predicted separation violations and more than 80% of the predicted violations between two arrival flights. Predicted separation violations between arrivals and non-arrivals were 32% of all predicted separation violations at Denver and 41% at Dallas/Fort-Worth. A probabilistic analysis of meter fix crossing-time errors is included which shows that some controller interventions will still be required even when the predicted crossing-times of the advisories are set to add a 1 or 2 nmi buffer above the minimum in-trail separation of 5 nmi. The 2 nmi buffer was shown to increase average flight delays by up to 30 sec when compared to the 1 nmi buffer, but it only resulted in a maximum decrease in average arrival throughput of one flight per hour.

Safety of hydrogen/natural gas mixtures by pipelines : ANR french project HYDROMEL

Scipedia content — Mon, 01 Feb 2021 21:05:23 +0100

International audience; In order to gain a better understanding of hazards linked with Hydrogen/Natural gas mixtures transport by pipeline, the National Institute of Industrial Environment and Risks (INERIS) alongside with the Atomic Energy Commission (CEA), the industrial companies Air Liquide and GDF SUEZ, and the French Research Institutes ICARE and PPRIME (CNRS) have been involved in a project called HYDROMEL. This project was partially funded by the French National Research Agency (ANR) in the framework of its PAN-H program aimed at promoting the R&D activities related to the hydrogen deployment. Firstly, the project partners investigated how a NG/H2 mixture may influence the modeling of a hazard scenario, i.e. how the addition of a quantity of hydrogen in natural gas can increase the potential of danger. Therefore it was necessary to build an experimental database of physics properties for mixtures. Secondly, effect distances in accidental scenarios that could happen on pipelines have been calculated with existing models adapted to the mixtures. This part was preceded by a benchmark exercise between all partners' models and experimental results found in the literature. Finally the consortium wrote a 'good practice guideline for modeling the effects related to the release of natural gas /hydrogen mixture'. The selected models and their comparison with data collected in the literature as well as the experimental results of this project, and the main conclusions of the guidelines are presented in this paper.

User Centered, Application Independent Visualization of National Airspace Data

Scipedia content — Mon, 01 Feb 2021 20:53:32 +0100

This paper describes an application independent software tool, IV4D, built to visualize animated and still 3D National Airspace System (NAS) data specifically for aeronautics engineers who research aggregate, as well as single, flight efficiencies and behavior. IV4D was originally developed in a joint effort between the National Aeronautics and Space Administration (NASA) and the Air Force Research Laboratory (AFRL) to support the visualization of air traffic data from the Airspace Concept Evaluation System (ACES) simulation program. The three main challenges tackled by IV4D developers were: 1) determining how to distill multiple NASA data formats into a few minimal dataset types; 2) creating an environment, consisting of a user interface, heuristic algorithms, and retained metadata, that facilitates easy setup and fast visualization; and 3) maximizing the user’s ability to utilize the extended range of visualization available with AFRL’s existing 3D technologies. IV4D is currently being used by air traffic management researchers at NASA’s Ames and Langley Research Centers to support data visualizations.

Modeling and analyzing transient military air traffic control

Scipedia content — Mon, 01 Feb 2021 20:53:15 +0100

theoretical application of transient queueing analysis is provided for military air traffic control. The exact distribution of the nth arriving or departing flight's sojourn time in an M/M/s queue with k flights initially present is reviewed. Algorithms previously developed for computing the covariance between sojourn times for an M/M/1 queue with k ≥ 0 flights present at time zero are provided and utilized. Maple computer code is utilized for practical applications in air traffic control of transient queue analysis for many system measures of performance without regard to traffic intensity (i.e., the system may be unstable with traffic intensity greater than one), thus negating the need for simulation.

Pedestrian Detectability: Predicting Human Perception Performance with Machine Vision

Scipedia content — Mon, 01 Feb 2021 20:38:22 +0100

How likely is it that a driver notices a person standing on the side of the road? In this paper we introduce the concept of pedestrian detectability. It is a measure of how probable it is that a human observer perceives pedestrians in an image. We acquire a dataset of pedestrians with their associated detectabilities in a rapid detection experiment using images of street scenes. On this dataset we learn a regression function that allows us to predict human detectabilities from an optimized set of image and contextual features. We exploit this function to infer the optimal focus of attention for pedestrian detection. With this combination of human perception and machine vision we propose a method we deem useful for the optimization of Human-Machine-Interfaces in driver assistance systems.

Complex event post processing for traffic accidents

Scipedia content — Mon, 01 Feb 2021 20:24:08 +0100

In this paper, we describe a framework for an expert system that tries to predict effects of an accident based on past data using supervised learning employing artificial neural networks. For this purpose, sensory data events are post processed in order to generate a reasonable mapping between input and output parameters in case an event is detected automatically or manually. The framework is intended to be used to take actions for reducing the effects of the accident on traffic congestion and to inform necessary parties to intervene in a timely fashion.

Formulation of Chlorine and Decontamination Booster Station Optimization Problem

Scipedia content — Mon, 01 Feb 2021 20:18:36 +0100

commonly used indicator of water quality is the amount of residual chlorine in a water distribution system. Chlorine booster stations are often utilized to maintain acceptable levels of residual chlorine throughout the network. In addition, hyper-chlorination has been used to disinfect portions of the distribution system following a pipe break. Consequently, it is natural to use hyper-chlorination via multiple booster stations located throughout a network to mitigate consequences and decontaminate networks after a contamination event. Many researchers have explored different methodologies for optimally locating booster stations in the network for daily operations. In this research, the problem of optimally locating chlorine booster stations to decontaminate following a contamination incident will be described.

Persistence and communication state transfer in an asynchronous pipe mechanism

Scipedia content — Mon, 01 Feb 2021 20:13:25 +0100

Emergent wide-area distributed systems like computational grids present opportunities for large scientific applications. On these systems, communication mechanisms have to deal with dynamic resource availability and occurrence of network failures. In this paper, we present the design and implementation of an asynchronous and persistent pipe mechanism, called pi-channels. These communication issues are addressed by combining adaptive caching with data streaming for efficient and fault-tolerant communication. We present the underlying distributed algorithm that implements (a) caching of pipe data segments; (b) asynchronous operation; and (c) re-establishment of connections when a peer leaves and rejoins the computation - part of a communication state transfer mechanism. This makes it possible for different segments (from cache and from writer) of the pipe data to be concurrently streamed to the migrated reader, reducing the retrieval time. Finally, we present some performance results showing the benefits of asynchronous operation.

Urban monitoring using NetKDE and VGI: network based kernel density estimation on volunteered geographic information applied to Baghdad, Iraq

Scipedia content — Mon, 01 Feb 2021 20:07:31 +0100

This paper presents a methodology for urban monitoring using volunteered geographic information (VGI) and journalism data Iraq war logs with network based kernel density estimation (NetKDE). It investigates, using spatio-temporal analysis, the evolution of urban events in Baghdad between 2004 and 2009. The extracted street network is based on the data distributed by OpenStreetMap (OSM). A total of 21,876 logged events, 66,648 network segments, 22,644 gridpoints (200m resolution grid) and 362,304 gridpoints (50m resolution grid) are used for the analysis. The methodology combines and adapts these VGI data and is mainly based on open source and/or publicly available software. It handles very large datasets with multiscale, multi-resolution and temporal perspectives. Fuzzy-set map comparison (FMC) is used to identify level of changes between each period of time. The methodology is already used in other fields of research being biology, urban planning, criminology or economic evelopment. It should help stakeholders in respective domain to analyze the evolution of network constrained events in multiple contexts. This paper is divided in three parts. Firstly, conceptual background of VGI, NetKDE and FMC is presented. Secondly, the methodology is illustrated using data Iraq war logs, OSM data and grids with two different resolutions. Thirdly, spatio-temporal analysis results are presented and discussed. Peer Reviewed

OpenEnergySim: Conducting behavioral studies in virtual worlds for sustainable transportation

Scipedia content — Mon, 01 Feb 2021 20:05:09 +0100

Intelligent Transport System (ITS) strategies can significantly reduce CO 2 emissions of vehicles. Since the impact of ITS measures is highly dependent on driver acceptance and compliance rates, it is important to study the response of human drivers to new ITS strategies (the “human factor”). However, there is currently no low-cost yet effective method to investigate the human factor. Conventional driving simulators offer high realism of the driving and traffic environment, but they are expensive, not easily accessible, and restricted to one driver at a time, and hence make it difficult to conduct large-scale behavioral studies. Web-based survey methods are accessible but they do not allow to capture a person's moment-by-moment driving behavior. Therefore, we propose OpenEnergySim, an online multi-user three-dimensional (3D) simulation space based on emerging 3D Internet technology. OpenEnergySim can provide three functions in a realistic and integrated environment: (1) driving simulation of multiple users (as graphical ‘avatars’) in a simulated traffic network by using computer keyboard or game wheel; (2) visualization of the result of microscopic traffic simulation and (metaphoric) visualization of CO 2 emissions; (3) a shared real-time collaboration space for testing and comparing the effects of “green” ITS strategies on CO 2 emission reduction. Those features make OpenEnergySim a highly accessible platform for conducting behavioral studies in the transport domain. Since driving simulators have to address behavioral validity concerns, we will present results of a study where “car following” behavior in the virtual world is compared to both real-world data and Gipps' car-following model.

Tomorrow's Car - For Today's People: Can Tilting Three Wheeled Vehicles be a Solution for the Problems of Today and the Future?

Scipedia content — Mon, 01 Feb 2021 19:56:28 +0100

The current automotive industry and todays car drivers are faced with every increasing challenges, not previously experienced. Climate Change, financial issues, rising fuel prices, increased traffic congestion and reduced parking space in cities are all leading to changes in consumer preferences and the requirements of modern passenger vehicles. However, despite the shift in the industry dynamics, the principal layout of a car hasn’t changed since its invention. The design of a ’conventional’ vehicle is still principally a matchbox with four wheels, one at each corner. The concept has served its purpose well for over 100 years, but such a layout is not suited to solving today’s problems. To address the range of problems faced by the industry, a number of alternative commuting vehicles have been developed. Yet the commercialization of these ‘alternative’ vehicles has yet to be successful. This is largely due failure of these vehicles to meet the changing demands of the industry and the limited understanding of consumer behaviour, motivation and attitudes. Deakin University’s Tomorrow’s Car concept tackles all of these problems. The vehicle is a novel three-wheeler cross over concept between a car and a motorbike that combines the best of both worlds. The vehicle combines the low cost, small size and ‘fun’ factor of a motorbike together with the safety, comfort and easy to drive features of a car produce a vehicle with a fuel efficiency better than either car or scooter. Intensive market research has been conducted for various major potential markets of alternative vehicles including India, China and Australia. The research analysed consumer attitudes in relation to narrow tilting vehicles, and in particular towards Deakin’s Tomorrow’s Car (TC). The study revealed that a relatively large percentage of consumers find such a concept very appealing. For the other consumers, the overall appearance and perception of safety and not the actual safety performance were found to be the most impeding factors of such vehicles. By addressing these issues and marketing the vehicle accordingly the successful commercialization of Tomorrow’s Car can be ensured.

En-Route Optimal Flight Planning Constrained to Pass Through Waypoints using MINLP

Scipedia content — Mon, 01 Feb 2021 19:48:09 +0100

In this paper we study the en-route strategic flight planning of a commercial aircraft constrained to pass through a set of waypoints whose sequence is not predefined. This problem has been solved as an hybrid optimal control problem in which, given the dynamic model of the aircraft, the initial and final states, the path constraints constituting the envelope of flight, and a set of waypoints in the European air space, one has to find the control inputs, the switching times, the optimal sequence of waypoints and the corresponding trajectory of the aircraft that minimize the direct operating cost during the flight. The complete layout of waypoints in the European airspace is reduced and waypoints are gathered into a small number of clusters. The aircraft is constrained to pass through one waypoint inside every cluster of waypoints. The presence of multi point constraints makes the optimal control problem particularly difficult to solve. The hybrid optimal control problem is converted into a mixed integer non linear programming problem first making the unknown switching times part of the state, then introducing binary variable to enforce the constraint of passing through one waypoint inside every cluster, and finally applying a direct collocation method. The resulting mixed integer non linear programming problem has been solved using a branch and bound algorithm. The cases studied and the numerical results show the effectiveness, efficiency and applicability of this method for enroute strategic flight plans definition.

Air Traffic Estimation and Decision Support for Stochastic Flow Management

Scipedia content — Mon, 01 Feb 2021 19:45:49 +0100

** † ‡ Development of a decision support system that uses real-time track data to estimate statistical parameters describing the stochastic traffic flow is described. Modern statistical decision theory is applied to optimize traffic flow. An advanced estimation algorithm provides the parameter estimates based on queuing network models of traffic flow. A hypothesis testing approach is developed for triggering traffic flow management initiatives in the terminal area, and a stochastic quadratic programming methodology is advanced to achieve flow control objectives such as runway load balancing. The use of this methodology is demonstrated using multi-day track data in the San Francisco terminal area. It is shown that the methodology can correctly identify the need for restricting the traffic flow into the terminal area, and provide decision support to balance the traffic flow at the runways under uncertain traffic flow conditions. The present approach can be extended to the creation of decision support tools for a wide variety of stochastic air traffic flow control situations.

Clear-Air Turbulence Impact Modeling Based on Flight Route Analysis

Scipedia content — Mon, 01 Feb 2021 19:29:43 +0100

In this study, a Route-Based Turbulent-Weather Avoidance Model (TWAM-R) is presented. TWAM-R improves a previously reported trajectory-based model which was tactical in nature. TWAM-R considers more strategic turbulence-avoidance decisions that are based on turbulence forecasts and pilot reports (PIREPs). TWAM-R identifies areas of reduced capacity and areas of potential hazards due to congestion caused by air traffic avoiding clear-air turbulence. The algorithm is explained and illustrated using real-life turbulence and air traffic demand data. This study is a part of a larger effort aimed at the creation of weather impact translation models which specify the link between the weather hazard causes and their impact on the National Airspace System (NAS).

Urban growth and transport: understanding the spatial temporal relationship

Scipedia content — Mon, 01 Feb 2021 19:23:20 +0100

This paper describes how public transport and urban growth are strongly related. In fact, there is a reciprocal relationship between transport and urban growth. In order to understand this relationship, it is necessary to analyze urban spatial temporal changes and their related causes and effects. An extensive evidence-based and scientific description of the relationship between urban growth and transport is presented in this paper. This relationship is specifically explored for Jeddah City, Saudi Arabia, applying spatial temporal analysis techniques from remote sensing and Geographic Information Systems (GIS). Spatial and statistical analyses have been used to analyze and relate urban growth and transport spatial temporal indicators. Results indicate a strong reciprocal relationship between urban growth and transport in Jeddah City. The paper found that transport infrastructure expansion strongly correlates with population growth, spatial expansion and land use change. Results also reveal that population growth has increased urban trips and the consequent travel demand, and there is imbalance between travel demand and transport infrastructure supply that explains the increase in congestion. This study also points out a strong significant influence of transport infrastructure on spatial temporal expansion and land use change. It is found that highways and main roads have stronger influence on spatial expansion and land use change in comparison with secondary roads. Although, this study provides significant information for transport and urban development policies, further research is encouraged to use spatial statistical analysis and dynamic modeling to study the reciprocal relationship between urban growth and transport.

Establishing a Risk-Based Separation Standard for Unmanned Aircraft Self Separation

Scipedia content — Mon, 01 Feb 2021 19:22:58 +0100

Unmanned Aircraft Systems require an ability to sense and avoid other air traffic to gain access to civil airspace and meet requirements in civil aviation regulations. One sense and avoid function is self separation, which requires that aircraft remain "well clear." An approach is proposed in this paper to treat well clear as a separation standard, thus posing it as a relative state between aircraft where the risk of collision first reaches an unacceptable level. By this approach, an analytically- derived boundary for well clear can be derived that supports rigorous safety assessment. A preliminary boundary is proposed in both time and distance for the well clear separation standard, and recommendations for future work are made.

Requirements for EV charge stations with photovoltaic generation and storage

Scipedia content — Mon, 01 Feb 2021 16:25:17 +0100

With the increase in electric mobility, public and private charge facilities will be required to provide solutions adjusted to the actual needs and requirements. A new methodology for dimensioning charge stations for electric vehicles (EVs) is presented in this paper. Such proposal is based on the Markov chains, and uses as output rates, the capabilities of the charge station in providing energy from the sun through photovoltaic generation, stored energy in local batteries and also as a back-up the power grid. A numerical result is also presented for a better understanding of the process.

Document type: Conference object

Geometrical and kinematic properties of interfacial waves in horizontal heavy oil-water stratified flow

Scipedia content — Mon, 01 Feb 2021 15:50:56 +0100

The oil-water stratified flow pattern is common in the petroleum industry, especially in offshore directional wells and pipelines. Previous studies have shown that the phenomenon of flow pattern transition in stratified flow can be related to the interfacial wave structure (problem of hydrodynamic instability). The study of the wavy stratified flow pattern requires the characterization of the interfacial wave properties, i.e., its nature (kinematic or dynamic), average shape, celerity and geometric properties as a function of holdup and phases’ relative velocity. However, the data available in the literature on wavy stratified flow is scanty, especially when oil is viscous. This paper presents geometric and kinematic interfacial wave properties as a function of holdup and relative velocity in the wavy stratified flow. The experimental work was conducted in a glass test line of 12 m and 0.026 m i.d., oil (density 828 kg / m³ and viscosity of 0.3 Pa.s at 20°C) and water as the working fluids at horizontal.

Observations from Several Condition Assessments of Prestressed Concrete Cylinder Pipe Used at Energy Generation Facilities

Scipedia content — Fri, 29 Jan 2021 00:57:58 +0100

Golder Associates Incorporated has conducted several condition assessments of prestressed concrete cylinder pipe (PCCP) used in the cooling water systems of energy generation facilities. This paper presents observations from these condition assessment projects. A vital component to the operation of energy generation facilities is the cooling water system. The cooling water system conveys cool water from a river or basin through the plant's condensers to condense steam produced in the process of power generation. The heated water is then returned to the river or basin, or sent through cooling towers to dissipate the gained heat. To work effectively, these systems typically operate with high flows (greater than 200,000 gpm) and low pressures (less than 60 psi) in large diameter pipelines (typically 54 to 120 in). These systems may provide cooling water to one or more units, and redundancy is not typical. Thus, the isolation of these systems for evaluation or repair may require the temporary shutdown of one or several units, resulting in significant costs associated with purchasing replacement power. Many utilities operating energy generation facilities constructed in the 1970s and 1980s have not included these cooling water systems in their general plant evaluation and maintenance schedule, and these systems have often operated continuously for over 30 years. Due to the increased awareness of plant personnel, and the age of their buried infrastructure, these systems are now being evaluated. Condition assessment of these systems is similar to other pipelines with tasks such as document review, physical evaluation and condition summary, but also requires detailed planning to coincide with planned unit outages, and in some cases requires significant coordination with other facilities to allow for several unit outages at the same time. Pipeline condition assessments conducted have identified a wide range of conditions for the 30- to 40-year-old PCCP used in cooling water systems, ranging from pristine pipe, to pipe that has technically failed. Factors contributing to the distress observed in the pipelines include the manufacturing practices (particularly the use of class IV prestressing wire), installation practices, nearby stray electric currents, groundwater quality and interaction, and operational stresses. Recommendations from these condition assessments have also varied greatly, from continued evaluation, instituting operational controls, or even complete replacement of distressed portions of the line.

Document Analysis Algorithm Contributions in End-to-End Applications: Report on the ICDAR 2011 Contest

Scipedia content — Fri, 29 Jan 2021 00:55:33 +0100

ISBN: 978-1-4577-1350-7; International audience; This contest aims to provide a metric giving indications on the influence of individual document analysis stages to overall end-to-end applications. Contestants are provided with a full, working pipeline which operates on a page image to extract useful information. The pipeline is built with clearly identified analysis stages (e.g. binarization, skew detection, layout analysis, OCR ...) that have a formalized input and output. Contestants are invited to contribute their own algorithms as an alternative to one or more of the initially provided stages. The evaluation measures the overall impact of the contributed algorithm on the final (end-of-pipeline) output.

Complexity Management Using Metrics for Trajectory Flexibility Preservation and Constraint Minimization

Scipedia content — Fri, 29 Jan 2021 00:43:31 +0100

The growing demand for air travel is increasing the need for mitigating air traffic congestion and complexity problems, which are already at high levels. At the same time new surveillance, navigation, and communication technologies are enabling major transformations in the air traffic management system, including net-based information sharing and collaboration, performance-based access to airspace resources, and trajectorybased rather than clearance-based operations. The new system will feature different schemes for allocating tasks and responsibilities between the ground and airborne agents and between the human and automation, with potential capacity and cost benefits. Therefore, complexity management requires new metrics and methods that can support these new schemes. This paper presents metrics and methods for preserving trajectory flexibility that have been proposed to support a trajectory-based approach for complexity management by airborne or ground-based systems. It presents extensions to these metrics as well as to the initial research conducted to investigate the hypothesis that using these metrics to guide user and service provider actions will naturally mitigate traffic complexity. The analysis showed promising results in that: (1) Trajectory flexibility preservation mitigated traffic complexity as indicated by inducing self-organization in the traffic patterns and lowering traffic complexity indicators such as dynamic density and traffic entropy. (2) Trajectory flexibility preservation reduced the potential for secondary conflicts in separation assurance. (3) Trajectory flexibility metrics showed potential application to support user and service provider negotiations for minimizing the constraints imposed on trajectories without jeopardizing their objectives.

Development of a Safety Assessment Methodology for the Risk of Collision of an Unmanned Aircraft System with the Ground

Scipedia content — Fri, 29 Jan 2021 00:42:59 +0100

ft, UAS performance characteristics are examined. This helps to clarify in which airspace classes the different available UAS may be able to fly. This concerns the broad range of size, various configurations and different performance characteristics. Next, causal models are developed for 15 accident scenario that may result in a collision with the ground. These causal models are represented as Event Sequence Diagrams (ESDs) and Fault Trees (FTs), and provide a logical structure showing how hazards and causal factors could combine to cause a collision with the ground. This approach utilizes the Causal model for Air Transport Safety (CATS) developed for the Dutch Ministry of Transport. Five specific UAS related ESDs are added to cover UAS specific hazards that do not exist in manned aircraft operation. Using the twenty ESDs, a UAS accident probability model for the risk of collision with the ground is developed.

Visual Simulation Environment

Scipedia content — Fri, 29 Jan 2021 00:30:26 +0100

Describes the Visual Simulation Environment (VSE) software product. VSE has been developed under $1.3 million of research funding, primarily from the US Navy, for over a decade. It enables discrete-event, general-purpose, object-oriented, picture-based, component-based, visual simulation model development and execution. This advanced environment can be used for solving complex problems in areas such as air traffic control and space systems, business process reengineering and workflows, complex system design evaluation, computer and communication networks, computer performance evaluation, education and training, health care systems, manufacturing systems, military/combat systems, satellite and wireless communications systems, service systems, supply chain management and transportation systems.

Computational Air Traffic Management

Scipedia content — Fri, 29 Jan 2021 00:25:10 +0100

This is a quasi-review paper which defines and then places Computational Air Traffic Management (CATM) in a historical context. CATM is presented as the natural convergence of many, seemingly disparate, air traffic technologies that have evolved over the past two decades. It is the emergent order which is derived from the collective behaviour of a number of interacting systems. A distinction is initially made between strategic air traffic management (ATM) and tactical air traffic control (ATC). This distinction ebbs in CATM and the intimately intertwined relationship between ATM and ATC is accentuated. The features of an ideal ATC system are discussed and developed objectively in contrast to current systems. The requirements are based on a high level top-down approach, but also look at the time-proven characteristics that allow the current ATC system to function so surprisingly well. An inventory of the interesting research questions in the overall CATM picture is therefore gradually drawn-up along the discussion to indicate areas with insufficient research coverage. In the second part of the paper, a clean sheet approach for devising an operational concept for a streamlined CATM system is proposed and discussed. This example describes an airborne, decentralized, fault-tolerant paradigm for a continental (and perhaps global) ATC system that readily scales up (perhaps linearly) to accommodate projected future aircraft densities. The system is broadly consistent with the proposed objectives as put forward in both NextGen (Next Generation Air Transportation System) and SESAR (Single European Sky ATM Research). Practical algorithms for several subsystems are classified, and discussed in the context of emerging computational hardware. The case is then made for a new breed of grid-oriented avionics hardware that will enable aircraft to take CATM to the skies by leveraging on the many benefits brought by pervasive inter-aircraft ad-hoc communication networks and heterogeneous, high performance grid-computing.

Design of an airport surface routing evaluation tool

Scipedia content — Fri, 29 Jan 2021 00:21:03 +0100

There are many studies related with airport surface routing algorithms, based on different approaches and with different evaluation methods and metrics. So, the need of performing a balanced analysis and comparison using a common framework is evident. This paper presents an implementation of an evaluation tool for airport surface routing algorithms. The routing evaluation tool presented here is based in three basic pillars composed by the airport model, the model and generation of traffic and a comprehensive figure of merit function. The paper includes some example evaluations performed over Barajas Airport with representative traffic samples using several simple routing methods.

A grouping model for distributed pipeline assets maintenance decision

Scipedia content — Fri, 29 Jan 2021 00:14:55 +0100

Distributed pipeline assets systems are crucial to society. The deterioration of these assets and the optimal allocation of limited budget for their maintenance correspond to crucial challenges for water utility managers. Decision makers should be assisted with optimal solutions to select the best maintenance plan concerning available resources and management strategies. Much research effort has been dedicated to the development of optimal strategies for maintenance of water pipes. Most of the maintenance strategies are intended for scheduling individual water pipe. Consideration of optimal group scheduling replacement jobs for groups of pipes or other linear assets has so far not received much attention in literature. It is a common practice that replacement planners select two or three pipes manually with ambiguous criteria to group into one replacement job. This is obviously not the best solution for job grouping and may not be cost effective, especially when total cost can be up to multiple million dollars. In this paper, an optimal group scheduling scheme with three decision criteria for distributed pipeline assets maintenance decision is proposed. A Maintenance Grouping Optimization (MGO) model with multiple criteria is developed. An immediate challenge of such modeling is to deal with scalability of vast combinatorial solution space. To address this issue, a modified genetic algorithm is developed together with a Judgment Matrix. This Judgment Matrix is corresponding to various combinations of pipe replacement schedules. An industrial case study based on a section of a real water distribution network was conducted to test the new model. The results of the case study show that new schedule generated a significant cost reduction compared with the schedule without grouping pipes.

A pattern recognition approach for anomaly detection on buses brake system

Scipedia content — Fri, 29 Jan 2021 00:11:11 +0100

Diagnosis of complex systems refers to the problem of identifying a breakdown or a failure based on an inspection, a control or a test. Monitoring such industrial complex systems is essential to schedule relevant maintenance actions. We consider an automotive subsystem to monitor: the brake system, because of its impact on the vehicles availability. Through a European project [1], data are acquired via in-vehicle communication protocols and additional sensors. This work aims at developing remote diagnostic and maintenance support tools driven by these data. Our approach combines an analytic model and detection techniques in order to monitor the brake system. We provide experimental results on vehicle data using two multivariate detection methods.

Triggering the development of electric mobility: a review of public policies

Scipedia content — Thu, 28 Jan 2021 23:58:46 +0100

disponible en ligne : http://www.springerlink.com/content/ghq570268853q546/fulltext.pdf (This article is published with open access at SpringerLink.com); International audience; The fundamental challenge of a massive deployment of electric mobility is the reduction of transportation's impact on climate. Hereby derived challenges specifically concern: (a) the organization of mobility together with the uptake of recharge infrastructure, (b) the interaction of the electric mobility system with the electricity net, hereby considering the energy storage function of batteries, (c) the technological progress and the industrial production of vehicles and various components. Overall, these stakes involve the community more than the individual vehicle user. This paper analyses public policies and projects in favour of electric mobility based on private or shared vehicle usage. An international review of national policies and regional projects is given. The conditions for availability and attractiveness of an electric mobility system to potential users are discussed, notably so with respect to the deployment of the recharging infrastructure and its adequacy to existing land-use patterns. Current policy approaches supporting the uptake of electric mobility are promising. For the time being, however, the complexity of the electromobility system impedes a valid conclusion on the effectiveness of measures put in place. Besides public policy intervention mainly also economic, technical and industrial factors will define the success of e-mobility. Upcoming years will allow first ex-post policy analyses.

Re-design of an inbound planning interface for air traffic control

Scipedia content — Thu, 28 Jan 2021 23:57:53 +0100

In the coming decades, the task of an air traffic controller is expected to shift to one of strategic, trajectorybased air traffic management. This form of air traffic control is no longer possible without the help of automated support tools. In previous research, it has been shown that the time-space diagram, combined with a conventional plan view display is a good candidate for supporting an air traffic controller with the inbound planning task in the future situation. However, in this initial study, the vertical plane was not yet fully included. Secondly, during an initial validation experiment, creating and maintaining a ’mental picture’ of the traffic was reported to be a difficult task. These findings lead to the re-design of the interface in the current research, which focuses on implementing the vertical plane and improving the integration of information across the successive displays. An experiment has been performed with a PC-based simulation which validates that the enhanced interface can be used to manage the air traffic safely and efficiently. Secondly, it has been shown that the ability to manipulate the speed of an aircraft in the adjacent sector can significantly increase situation awareness and reduce controller workload.

Beyond MLU: An application-centric comparison of traffic engineering schemes

Scipedia content — Thu, 28 Jan 2021 23:55:17 +0100

Traffic engineering (TE) has been long studied as a network optimization problem, but its impact on user-perceived application performance has received little attention. Our paper takes a first step to address this disparity. Using real traffic matrices and topologies from three ISPs, we conduct very large-scale experiments simulating ISP traffic as an aggregate of a large number of TCP flows. Our application-centric, empirical approach yields two rather unexpected findings. First, link utilization metrics, and MLU in particular, are poor predictors of application performance. Despite significant differences in MLU, all TE schemes and even a static shortest-path routing scheme achieve nearly identical application performance. Second, application adaptation in the form of location diversity, i.e., the ability to download content from multiple potential locations, significantly improves the capacity achieved by all schemes. Even the ability to download from just 2–4 locations enables all TE schemes to achieve near-optimal capacity, and even static routing to be within 30% of optimal. Our findings call into question the value of TE as practiced today, and compel us to significantly rethink the TE problem in the light of application adaptation.

Urban electrical vehicles as the solution for public transportation in the cities of Romania

Scipedia content — Thu, 28 Jan 2021 23:47:46 +0100

This paper shows that the European Recommendation COM (2007) 551 final finds that over 60% of the population lives in urban areas in the European Union (EU). Urban areas now constitute the living environment of the majority of the population and increased traffic in town and city centers has resulted in chronic congestion. Every year nearly 100 billion Euros, or 1% of the EU’s gross domestic product (GDP), are lost to the European economy as a result of this congestion. The analysis of the means of transport presented in this paper will show which electrical vehicle is the solution for non-polluting transport according to each specific need. The Romanian company ICPE SAERP, together with the Urban Transport Administration of Bucharest (RAT Bucharest), has modernized classic tramcars, equipping them with three-phase inverters and asynchronous motors and a partially lowered floor. By 2011, 18 tramcars will be modernized. ICPE SAERP together with ASTRA BUS Arad, will produce and deliver new trolleybuses with lowered floors in Bucharest. These new trolleybuses will be equipped with three-phase inverters, with asynchronous motors and with converters for the auxiliary services and for the air conditioning system. Also the trolleybus has a protection device against high voltage present on the body of the vehicle, which is controlled by means of a DSP processor in the master controller. The methodology used in the authors research is presented in this paper as well as the results that led to the conclusion that the type of public transportation proposed is cleaner, more reliable, more efficient and more comfortable than others.

Exploring spatiotemporal patterns by integrating visual analytics with a moving objects database system

Scipedia content — Thu, 28 Jan 2021 23:32:21 +0100

International audience; In previous work, we have proposed a tool for Spatiotemporal Pattern Query. It matches individual moving object trajectories against a given movement pattern. For example, it can be used to find the situations of Missed Approach in ATC data (Air Traffic Control systems, used for tracking the movement of aircrafts), where the landing of the aircraft was interrupted for some reason. This tool expresses the pattern as a set of predicates that must be fulfilled in a certain temporal order. It is implemented as a Plugin to the Secondo DBMS system. Although the tool is generic and flexible, domain expertise is required to formulate and tune queries. The user has to decide the set of predicates, their arguments, and the temporal constraints that best describe the pattern. This paper demonstrates a novel solution where a Visual Analytics system, V-Analytics, is used in integration with this query tool to help a human analyst explore such patterns. The demonstration is based on a real ATC data set.

VirtualKnotter: Online Virtual Machine Shuffling for Congestion Resolving in Virtualized Datacenter

Scipedia content — Thu, 28 Jan 2021 23:13:32 +0100

Our measurements on production data center traffic together with recently reported results suggest that data center networks suffer from long-lived congestion caused by core network over subscription and unbalanced workload placement. In contrast to traditional traffic engineering approaches that optimize flow routing, in this paper, we explore the opportunity to address the continuous congestion via optimizing VM placement in virtualized data centers. To this end, we present Virtual Knotter, an efficient online VM placement algorithm to reduce congestion with controllable VM migration traffic as well as low time complexity. Our evaluation with both real and synthetic traffic patterns shows that Virtual Knotter performs close to the baseline algorithm in terms of link unitization, with only 5%-10% migration traffic of the baseline algorithm. Furthermore, Virtual Knotter decreases link congestion time by 53% for the production data center traffic.

Analysis of Mental Workload during En-route Air Traffic Control Task Execution Based on Eye-Tracking Technique

Scipedia content — Thu, 28 Jan 2021 23:09:30 +0100

International audience; This text aims to present a study which deals with mental workload evaluation during task execution. It is focused on the Air Traffic Controllers working situation. In this document, we mainly introduce an experiment which has been conducted in a French En-Route air traffic center with the participation of Air Traffic Controllers. Four principal experiment characteristics are detailed: the experiment procedure, the working situation elaborated for our experimentation, the nature of the task achieved by participants, and the technique chosen to analyze mental workload felt by operators. We finally present the main results from our first data analysis which seem to confirm major observations known in the field of air traffic control, as well as, mental workload study field.

Electric mobility in Portugal : municipal plans for its promotion

Scipedia content — Thu, 28 Jan 2021 22:56:13 +0100

The electric mobility program in Portugal is based on four strategic areas, namely the business model, infrastructure, incentives and communication, also supported by a completely adjusted legislation, which is subjacent to the priorities defined in the Portuguese Program for Electric Mobility. A Model for Electric Mobility was also defined, supported by four main components: the value chain, actors, charging network and operation of the pilot-phase. In this work the different phases of implementation of this Program will be identified, with particular emphasis to the measures and incentives in the pilot-phase to promote the use of electric vehicles, such as the development of 25 municipal plans to promote the electric mobility at a local level, covering the principal municipalities of the country to generate a coherent and logical charging network. This paper presents the first steps in electric mobility planning in Portugal in order to justify the decisions taken by the municipalities in this very early stage of its implementation. As an example, the results for the municipality of Beja, located in South of Portugal, will be presented.

Erasing Core Boundaries for Robust and Configurable Performance

Scipedia content — Thu, 28 Jan 2021 22:52:07 +0100

Single-thread performance, reliability and power efficiency are critical design challenges of future multicore systems. Although point solutions have been proposed to address these issues, a more fundamental change to the fabric of multicore systems is necessary to seamlessly combat these challenges. Towards this end, this paper proposes Core Genesis, a dynamically adaptive multiprocessor fabric that blurs out individual core boundaries, and encourages resource sharing across cores for performance, fault tolerance and customized processing. Further, as a manifestation of this vision, the paper provides details of a unified performance-reliability solution that can assemble variable-width processors from a network of potentially broken) pipeline stage-level resources. This design relies on interconnection flexibility, micro architectural innovations, and compiler directed instruction steering, to merge pipeline resources for high single-thread performance. The same flexibility enables it to route around broken components, achieving sub-core level defect isolation. Together, the resulting fabric consists of a pool of pipeline stage-level resources that can be fluidly allocated for accelerating single-thread performance, throughput computing, or tolerating failures.

Effect of Uncertainty on Deterministic Runway Scheduling

Scipedia content — Thu, 28 Jan 2021 22:37:24 +0100

ve runway scheduling involves scheduling departures for takeoffs and arrivals for runway crossing subject to numerous constraints. This paper evaluates the effect of uncertainty on a deterministic runway scheduler. The evaluation is done against a firstcome-first-serve scheme. In particular, the sequence from a deterministic scheduler is frozen and the times adjusted to satisfy all separation criteria; this approach is tested against FCFS. The comparison is done for both system performance (throughput and system delay) and predictability, and varying levels of congestion are considered. The modeling of uncertainty is done in two ways: as equal uncertainty in availability at the runway as for all aircraft, and as increasing uncertainty for later aircraft. Results indicate that the deterministic approach consistently performs better than first-come-first-serve in both system performance and predictability.

The Use of Bicycle Messengers in the Logistics Chain, Concepts Further Revised

Scipedia content — Thu, 28 Jan 2021 22:27:41 +0100

The paper deals with the use of bicycle messengers, also called bike couriers, in the modern logistics chain. In an era where almost every actor - from policy makers to senior managers - is thinking about the environment and sustainability, new innovative concepts are developed worldwide. On the other hand, an abundance of solutions to improve efficiency and overall sustainability of logistics and other related business activities are already available in the market. Reinventing the wheel all over again might not be necessary. One of the methods to deliver parcels in a more sustainable way, is the transport of freight by bike. People on bike deliver and transport post, parcels or freight with a low volume or weight. Bike couriers are proven to be fast and reliable within congested urban areas. These bikers mainly advertised their ability to go fast from one place to another in a city. Sustainability was a selling argument, but speed was of more importance. Also, in Europe some bike courier markets are reasonably well developed. Specific markets seem to exist for transport of freight by bike. The research question of this paper concerning bicycle messengers is whether these companies can be an economic viable alternative for fossil fuel powered transport, and if so, in what markets these opportunities can be found. The authors draw conclusions about the business model and integrate encountered weaknesses and opportunities. An operational cost calculation is included. A simulation of a round trip delivery scheme in an urban area took place. A van as well as a bike courier solution was compared. To draw some conclusions about the economic feasibility of the round trip by bike courier, the cost per stop is compared and will be discussed. The paper ends with a conclusion on the observations made, and with a number of recommendations. (C) 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the 7th International Conference on City Logistic

Pipeline Engineering: How to Plan for Everything

Scipedia content — Thu, 28 Jan 2021 22:20:10 +0100

Every large pipeline project has its own unique design elements and surprises. Anticipating and knowing how to prepare for these potential issues is critical to the successful design, construction and operation of the pipeline. During Preliminary Engineering for pipeline projects there are a few guiding principles that every team should follow to plan the project effectively. Since a thorough Preliminary Engineering evaluation is fundamental for a project's success, these guiding principles cannot be ignored. This paper provides the planning principles and a detailed checklist for owners and engineering managers to utilize during the planning stages of a major pipeline project. Utilization of these tools will help identify potential surprises encountered on each pipeline project earlier than before. These principles and checklist have been developed through experience of planning and design of over 400 miles of large diameter pipelines in mostly urban environments. Planning for everything may seem too cumbersome to accomplish, but this paper will simplify the process for a majority of the typical challenges and include examples from previous lessons learned.

Comparison of Trajectory Synthesis Algorithms for Monitoring Final Approach Compression

Scipedia content — Thu, 28 Jan 2021 22:11:49 +0100

This study analyzes the performance of aircraft in-trail separation monitoring algorithms using 480,000 flights on the final approach courses of 25 major airports in the National Airspace System. While compression monitoring is expected to help air traffic controllers achieve and maintain higher arrival rates, the trajectory prediction requirements for it are not well understood. To address this gap, analytical trajectories were constructed from flight plan and track data for flights arriving at the 14 major and 11 satellite airports of the 8 busiest terminal areas. Three types of analytical trajectory models were compared. These trajectory models were a constant speed model, and two heuristic deceleration models. The trajectory prediction accuracy and separation prediction accuracy of each of these models were calculated for all aircraft pairs along the final approach course. The results were used to rank the overall performance of the various trajectory models in terms of the true and false alerts by the compression monitoring algorithms. The best performing trajectory model enforced the landing speed constraint, used a landing speed based upon weight class, and did not adjust the landing speed by airport elevation. All of the trajectory models exhibited significantly more false alarms when excess in-trail separation was less than 0.5 nm.

Innovative Micro-Walking Robot Using Flexible Microactuator

Scipedia content — Thu, 28 Jan 2021 21:59:49 +0100

In the area of Robotics, the micro-walking robots play a very important role as it is required to perform inspection and maintenance inside pipelines or narrow spaces where people cannot enter. Extensive research work is under way in the design and control of the micro-walking robot. An exhaustive survey of all such robots conveys the idea of higher and higher sophistication with innumerable components and elaborate controls with programmable ability. Microwalking robots proposed by earlier researchers use flexible micro actuators that have two or more internal chambers whose internal pressures are controlled independently. The proposed micro-walking robot uses flexible micro actuators (FMA) that are having single internal chamber with an innovative Electro-pneumatic control algorithm (EPCA), simple feedback mechanism and which are compact and easy to manufacture. The present work has paved the way for extensive research on this innovative technique as it holds out the true potential for very interesting applications in various areas such as robot grippers, pipeline inspection robots and underwater robots.

Problems with Operational Pigging In Low Flow Oil Pipelines

Scipedia content — Thu, 28 Jan 2021 21:40:22 +0100

Pigging of pipelines within the oil industry has been around for well over 100 years and has been used as the preferred (if not the only) internal method for cleaning, maintaining operational efficiency, data gathering and inspection for integrity management purposes. The benefits in carrying out routine “operational” pigging cannot be underestimated and operational pigging to remove water, wax, scale and other debris which is formed during routine operations whilst transporting crude oil and gas is paramount in maintaining the integrity of any crude oil and gas pipeline system. The build up of such debris is common whether the pipeline is offshore between production platforms, from a production platform to onshore or a totally land based pipeline. Similar problems are encountered to varying degrees dependent on pipeline size, location and type of the crude product being transported. Pipelines are normally designed for a specific maximum flowrate, this maximum rate is generally maintained on a “plateau” for several years of a field’s life, during which routine pigging operation presents little or no real problem to the pipeline operator. The cleaning pigs which are used are generally designed for the “maximum” of “potential flowrate” which the pipeline is due to see during it’s plateau phase of operation. This assumption, that these pigs will be suitable for the life of field operations, is common place with pipeline operators and as such there is a significant increase in the risk that pigs will become “stalled” on a regular basis or potentially “stuck” causing significant disruption to operation, production and in the worst case scenario a very costly subsea intervention. As can be seen from Industry Analysts¹ there will be a decline in overall oil production not just from the UK Sector but from the North Sea Basin and Europe as a whole. Therefore the need to understand pigging operations in “low flow” modes of operation cannot be stressed highly enough.

Distributed joint optimization of traffic engineering and server selection

Scipedia content — Thu, 28 Jan 2021 21:33:22 +0100

Internet service providers (ISP) apply traffic engineering (TE) in the underlay network to avoid congestion. On the other hand, content providers (CP) use different server selection (SS) strategies in the overlay network to reduce delay. It has been shown that a joint optimization of TE and SS is beneficial to the performance from both ISP's and CP's perspectives. One challenging issue in such a network is to design a distributed protocol which achieves optimality while revealing as little information as possible between ISP and CP. To address this problem, we propose a distributed protocol termed PETS, in which each router of ISP makes independent traffic engineering decision and each server of CP makes independent server selection decision. We prove that PETS can achieve optimality for the joint optimization of TE and SS. We also show that PETS can significantly reduce message passing and enables ISP to hide important underlay network information (e.g., topology) from CP. Furthermore, PETS can be easily extended to handle the case of multiple CPs in the network.

Regulation of the wind power production: contribution of the electric vehicles and other energy storage systems

Scipedia content — Thu, 28 Jan 2021 21:29:17 +0100

The increase in penetration of variable renewable energy sources (RES) introduced additional difficulties regarding the management of the Portuguese Power System. This is mainly due to the high temporal variability and low controllability, characteristics of these kinds of sources. There is a real need to reduce the impact of non-dispatchable RES sources; maximizing their penetration and minimizing curtailment. This is especially true for the wind power and run-of-the-river hudro (ROR); as it appears beneficial to combine their variable production with added capacity of energy storage and demand side management; thereby increasing the flexibility of the power system as a whole. This paper aims to assess the excess wind generation (and other non-dispatchable sources); this for periods of production's excess in a 2020 timeframe, and assuming different weather scenarios. The adjustment of wind power generation (WPG) profile to the load prfile is also addressed; the result is computed in the form of the value of the energy temporally deferred, using Pumped Hydro Storage (PHS) power plants as well as electric Vehicles (EVs)

ITS‐Cloud: Cloud Computing for Intelligent Transportation System

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

International audience; Intelligent transportation clouds could provideServices such as autonomy, mobility, decision support and thestandard development Environment for traffic managementstrategies, and so on. With mobile agent technology, anurban-traffic management system based on Agent-BasedDistributed and Adaptive Platforms for Transportation Systems(Adapts) is both feasible and effective. However, the large-scaleuse of mobile agents will lead to the emergence of a complex,powerful organization layer that requires enormous computingand power resources. To deal with this problem, we propose aprototype urban-traffic management system using multi agentbased intelligent traffic clouds. Cloud computing can help us tohandle the large amount of storage resources and masstransportation of data effectively and efficiently.

Planning Future Electric Vehicle Central Charging Stations Connected to Low-Voltage Distribution Networks

Scipedia content — Thu, 28 Jan 2021 21:23:23 +0100

great interest is recently paid to Electric Vehicles (EV) and their integration into electricity grids. EV can potentially play an important role in power system operation, however, the EV charging infrastructures have been only partly defined, considering them as limited to individual charging points, randomly distributed into the networks. This paper addresses the planning of public central charging stations (CCS) that can be integrated in low-voltage (LV) networks for EV parallel charging. The concepts of AC and DC architectures of CCS are proposed and a comparison is given on their investment cost. Investigation on location and size of CCS is conducted, analyzing two LV grids of different capacity. The results enlighten that a public CCS should be preferably located in the range of 100 m from the transformer. The AC charging levels of 11 kW and 22 kW have the highest potential in LV grids. The option of DC fast-charging is only possible in the larger capacity grids, withstanding the parallel charge of one or two vehicles.

A Novel Technique for Monitoring Hydrate Safety Margin

Scipedia content — Thu, 28 Jan 2021 21:18:38 +0100

Great concerns with flow assurance issues have been raised by the oil and gas industry, while the industry is increasingly moving to deepwater reservoirs. Gas hydrate blockages are one of the most common risks for the long distance offshore gas and oil production transport pipelines. Various types of hydrate inhibitors are usually deployed to ensure unimpeded flow of hydrocarbons. At present hydrate inhibitors are injected at the upstream of the pipelines according to approximate assessment of the flowing conditions including the produced water cut and the hydrate phase boundary that is determined based on the worst temperature and pressure conditions, without any means of monitoring the actual degree of inhibition along the pipeline. A novel technique has been developed to optimize the injection of hydrate inhibitors by monitoring the actual hydrate safety margin (i.e., degree of inhibition), which makes it possible to reduce unnecessary cost and potential impact on the environment. It measures the acoustic velocity and electrical conductivity of downstream aqueous samples and then determines both the inhibitor concentration and salt concentration through a trained artificial neural network. The hydrate phase boundary, hence the hydrate safety margin, are finally determined by an integrated in-house thermodynamic model using the determined salt and inhibitor concentrations. Its performance has been intensively evaluated using synthetic samples and real produced water samples by the authors and some oil & gas and service companies. This communication reports the success in development of the hydrate inhibition monitoring system. Results of the evaluation demonstrate that the system can be used for different inhibition systems including methanol-salt systems, mono ethylene glycol- salt systems, and kinetic hydrate inhibitor-salt systems with an acceptable measurement accuracy.

Some Possible Aplications Of Electric Drives in Military Vehicles

Scipedia content — Thu, 28 Jan 2021 21:12:01 +0100

The major advantages of electric propulsion compared to conventional power transmission drive of diesel engine to the wheels are presented and explained. It is in briefly showed development of some electrical vehicles in our country. The analysis of the electric drive showed some advantages of electric propulsion, such as operation without thermo emission of the vehicle, improved maneuvering and noiseless operating of the vehicle and saving fossil fuel. For any applications, hybrid vehicles have some good features of electric drive and vehicles with IC engines. Some military applications in the world of electric vehicle will be shown in this paper.

An adaptive learning algorithm for a route choice problem in uncertain traffic environments

Scipedia content — Thu, 28 Jan 2021 21:02:10 +0100

This paper describes how user equilibrium in a congested network has been conventionally formulated using mathematical optimization procedures. These approaches assume drivers’ behaviors with complete information in the sense that each driver knows the other drivers’ behaviors and their payoff functions. If each driver doesn’t know the other drivers’ strategies, they cannot optimize each others’ strategy. In such a situation, an adaptive heuristics may be a relevant approach to obtain a better solution. To establish behavioral rules of route choice under incomplete information, the paper uses a smooth fictitious play and a regret matching model developed in game theory. The model combines these two approaches. The paper also proposes a new algorithm that can be applicable to a complex situation in traffic environments.

When trains go faster than planes: the strategic reaction of airlines in Spain

Scipedia content — Thu, 28 Jan 2021 21:00:23 +0100

Plans for the development of high speed railway lines (HSR) in Spain were recently realised. At the beginning of 2010, four HSR lines were operating along routes where air transport was previously dominant. In this paper, we examine through econometric means the air carriers’ reaction to these HSR entrances into the transport market with data at the route level. We test whether the HSR lines have affected the airlines’ travel frequencies and market shares. Our results show that on average, HSR has reduced the number of air transport operations by 17 per cent. At the same time, travel demand has increased substantially, though the share of air transport in the total market has declined, as has the share of the dominant Spanish air carrier, Iberia.

A validation study of merging and spacing techniques in a NAS-wide simulation

Scipedia content — Thu, 28 Jan 2021 20:57:15 +0100

In November 2010, Intelligent Automation, Inc. (IAI) delivered a software tool to NASA Langley that models Merging and Spacing (M&S) for arrivals and departures in the Airspace Concepts Evaluation System (ACES) NAS-wide simulation. This delivery allows researchers to use ACES for system-level studies of the complex terminal airspace. As a precursor to use of the tool for research, the software was evaluated against current day arrivals in the Atlanta TRACON using Atlanta's Hartsfield-Jackson International Airport (KATL) arrival schedules, Standard Terminal Arrival Routes (STARs), and traffic flow management (TFM) techniques typical for Atlanta. Results of this validation effort are presented describing data sets, traffic flow assumptions and techniques, and arrival rate comparisons between reported landings at Atlanta versus simulated arrivals using the same traffic sets in ACES equipped with M&S. Since emphasis for intended research is on arrival capacity, this was also the focus of the validation. Before testing began, the simulated system was expected to demonstrate superior capacity over current day Atlanta by managing spacing intervals efficiently and exactly. Initial results, instead, showed the simulation's modeled capacity to be far short of what human controllers currently achieve, despite the efficiently managed spacing. Investigation into the cause of the shortfall revealed aspects of systems-level flow and control techniques that are critical to achieving sustained high capacity in the face of varying traffic loads and type mixes. This new understanding, once applied to the current day validation model, allowed a match of Atlanta's arrival capacity as well as a better understanding of how modern airports are limited by current day route models. Following this validation effort, a sensitivity study was conducted to measure the impact of variations in system parameters on the Atlanta airport arrival capacity.

Metrics and Analysis Methods for Evaluation of a Real-Time Automated Separation Assurance System

Scipedia content — Thu, 28 Jan 2021 20:53:36 +0100

*A system of metrics and analysis plots has been developed in order to evaluate the effectiveness and accuracy of trajectory prediction and automated conflict prediction and resolution algorithms. This research is conducted using a real-time air traffic management system to perform experimental runs using both live and simulated air traffic scenarios. The resulting data from these runs needs to be analyzed both to evaluate the performance of the software and to create objective metrics and plots for use in research studies. Specific analysis methods have been developed to assess data runs based on losses of legal separation between aircraft, conflict detections, trajectory prediction error, flight amendments, leveloffs, and fuel burn. I. Introduction ASA is developing tools and concepts to assist air traffic controllers in ensuring safe and efficient operations under increasing traffic demand. This work is divided into specialized tasks to focus on addressing specific air traffic management (ATM) needs. One such task is Separation Assurance (SA) research whose primary goals are to study automated algorithms for ensuring adequate separation between aircraft and to improve traffic flow through Air Route Traffic Control Center (ARTCC), or Center, airspace by using efficient, conflict-free flight paths. 1 In this research, the Center TRACON Automation System (CTAS) 2-4 is an important ATM tool with capabilities for automated conflict detection and resolution used as an experimental environment for comparing actual and simulated air traffic scenarios. The evaluation of the performance of this system under real-time traffic conditions is critical for proving the effectiveness of automated separation assurance algorithm

Intelligent management of end consumers loads including electric vehicles through a SCADA system

Scipedia content — Thu, 28 Jan 2021 20:50:14 +0100

The large penetration of intermittent resources, such as solar and wind generation, involves the use of storage systems in order to improve power system operation. Electric Vehicles (EVs) with gridable capability (V2G) can operate as a means for storing energy. This paper proposes an algorithm to be included in a SCADA (Supervisory Control and Data Acquisition) system, which performs an intelligent management of three types of consumers: domestic, commercial and industrial, that includes the joint management of loads and the charge/discharge of EVs batteries. The proposed methodology has been implemented in a SCADA system developed by the authors of this paper – the SCADA House Intelligent Management (SHIM). Any event in the system, such as a Demand Response (DR) event, triggers the use of an optimization algorithm that performs the optimal energy resources scheduling (including loads and EVs), taking into account the priorities of each load defined by the installation users. A case study considering a specific consumer with several loads and EVs is presented in this paper.

A decentralized event-based predictive navigation scheme for Air-Traffic Control

Scipedia content — Thu, 28 Jan 2021 20:32:04 +0100

This paper presents an approach for the multiagent navigation and conflict resolution problem, that considers the issue of performance. We present a decentralized predictive navigation scheme that combines the Decentralized Navigation Functions methodology with the Model Predictive Control (MPC) framework while preserving the former's collision avoidance and convergence guarantees. Aircrafts, flying at constant altitude, are modeled as unicycles. Performance criteria are encoded in a cost functional. Due to decentralization, each agent does not take into account the decisions of others in the control law calculation, resulting in performance discrepancies. Therefore, we employ event-triggered executions in our scheme. The improved performance is demonstrated through simulations.