Scipedia: Documents published in 2015

Metropolis: Relating Airspace Structure and Capacity for Extreme Traffic Densities

Scipedia content — Tue, 02 Feb 2021 02:56:05 +0100

International audience; Personal and unmanned aerial vehicles have received increasing media attention over the last decade. As a result of the growing excitement for these two aircraft types, many within and outside the aerospace industry envision a future in which large numbers of small aircraft fly over urban areas. With this vision for the future, the question arises what would be required, in terms of airspace organization, to make this feasible, or in deed, if it will be possible at all. In this context, the Metropolis project aims to investigate the influence of airspace structure on capacity, complexity, safety, and efficiency for high - density airspace. To this end, four airspace concepts, ranging fro m a decentralized direct routing concept, to a highly structured tube network using 4D trajectory - based operations, have been considered. The four concepts were compared by means of large - scale simulation experiments, for multiple scenarios that are extrem e when compared to current air traffic densities. This paper presents an overview of the Metropolis project with a focus on the project objectives, design and implementation of airspace concepts, and preliminary simulation results.

A Speech-Enabled Simulation Interface Agent for Airspace System Assessments

Scipedia content — Tue, 02 Feb 2021 02:52:48 +0100

Extensive human-in-the-loop testing of the Next-Generation Air Transportation System (NextGen) concepts and technologies is typically required in a controlled lab environment before they can be integrated for evaluation in the field. The experiments tend to require the participation of a large number of subject-matter experts (SMEs) including air traffic controllers (ATC) and (pseudo-)pilots, where such requirements make the experiments costly and the logistics with so many participants make them difficult to plan. These experiments often are designed only to collect data from either ATC or the pilots, but seldom both; the counterpart is needed only to provide realism in communication between them. The paper illustrates our research in developing a Speech-Enabled Simulation Interface Agent (SESIA) to replace the non-essential human subjects in these experiments. SESIA can interact with the SMEs through voice communication, and interface with the simulation platform to perform the intended control. It has the benefit of reduced cost associated with the experiments and increased convenience in their planning, thus allowing the opportunities to schedule additional testing. In cases where a pseudo-pilot would normally represent multiple flights and communicate to the ATC with the same voice for all flights, SESIA will actually increase the realism of the experiments by allowing different voices to be synthesized to simulate different pilots.

Overview of the HAIC “Space-borne Observation and Nowcasting of High Ice Water Content Regions” Sub-Project and Mid-Term Results

Scipedia content — Tue, 02 Feb 2021 02:47:23 +0100

International audience; The High Altitude Ice Crystals (HAIC) Sub-Project 3 (SP3) focuses on the detection of cloud regions with high ice water content (IWC) from current available remote sensing observations of space-based geostationary and low-orbit missions. The SP3 activities are aimed at supporting operationally the two up-coming HAIC flight campaigns (the first one in May 2015 in Cayenne, French Guyana; the second one in January 2016 in Darwin, Australia) and ultimately provide near real-time cloud monitoring to Air Traffic Management. More in detail the SP3 activities focus on the detection of high IWC from space-borne geostationary Meteosat daytime imagery, explore the synergy of concurrent multi-spectral multiple-technique observations from the low-orbit A-Train mission to identify specific signatures in high IWC cloud regions, and finally develop a satellite-based nowcasting tool to track and monitor convective systems over the Tropical Atlantic. The paper presents the HAIC SP3 objectives and provides an objective status of the sub-project at mid term of the HAIC project.

Material property relationships for pipeline steels and the potential for application of NDE

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

The oil and gas industry in the USA has an extensive infrastructure of pipelines, 70% of which were installed prior to 1980, and almost half were installed during the 1950s and 1960s. Ideally the mechanical properties (i.e. yield strength, tensile strength, transition temperature, and fracture toughness) of a steel pipe must be known in order to respond to detected defects in an appropriate manner. Neither current in-ditch methods nor the ILI inspection data have yet determined and map the desired mechanical properties with adequate confidence. In the quest to obtain the mechanical properties of a steel pipe using a nondestructive method, it is important to understand that there are many inter-related variables. This paper reports a literature review and an analysis of a sample set of data. There is promise for correlating the results of NDE measurement modalities to the information required to develop relationships between those measurements and the mechanical measurements desired for pipelines to ensure proper response to defects which are of significant threat.

Reassessing the financial and social costs of public transport

Scipedia content — Tue, 02 Feb 2021 02:45:59 +0100

This paper uses a previously developed spreadsheet cost model which simulates public transport modes operated on a 12km route to analyse the total costs of different passenger demand levels. The previous cost model was a very powerful tool to estimate the social and operator cost for different public transport technologies. However, as the model is strategic based, some assumptions are very basic and idealized and the demand was assumed to be exogenous (externally fixed). When the level of demand is high for the lower capacity public transport technologies, passengers may find the incoming vehicle full and therefore they have to wait more than one service interval. This paper applies queueing theory to investigate the probability of having to wait longer than the expected service headways which will affect the average passenger waiting time. The extra waiting time for each passenger is calculated and applied in the spreadsheet cost model. The speed-flow equation in the original spreadsheet model assumes the speed decreases according to the ratio of the current frequency and the lane capacity which is based on the safety headway without any passenger boarding. However, this may vary in different operating environments. Therefore, the speed equation is improved by moving from a linear equation to a piecewise equation that considers the features of different operating environments. To evaluate the differences after applying these equations, endogenous demand rather than exogenous demand will be investigated by using the elasticities for passenger waiting time and journey time.

TOWARDS EVALUATION TOOLS FOR LAST MILE DELIVERY PROJECTS: INSIGHTS FROM FRANCE

Scipedia content — Tue, 02 Feb 2021 02:40:17 +0100

International audience

On the study of human reliability in transportation systems of systems

Scipedia content — Tue, 02 Feb 2021 02:38:37 +0100

International audience; Humans are and will remain one of the critical constituents of a technological system. The study of Human Factors is a broad domain with equally varying applications. Quantification thereof, with a Human Reliability Analysis (HRA) poses considerable challenges and advantages. In increasingly complex modern systems where large resources are allocated towards ensuring system's operational safety, it becomes necessary to analyze the actions of human operator who directly or indirectly influences system reliability. This paper envisages establishing a base towards a HRA model, to address existing issues. Railway systems and Advanced Driver Assistance Systems for automobiles are our application domains; we aim to identify the need of and usability in both. Human considered as a component of the System of Systems for risk assessment allows us to study its impact on system reliability and give feedback to improve system safety.

One Sketch to Rule Them All

Scipedia content — Tue, 02 Feb 2021 02:31:33 +0100

Network management requires accurate estimates of metrics for traffic engineering (e.g., heavy hitters), anomaly detection (e.g., entropy of source addresses), and security (e.g., DDoS detection). Obtaining accurate estimates given router CPU and memory constraints is a challenging problem. Existing approaches fall in one of two undesirable extremes: (1) low fidelity general-purpose approaches such as sampling, or (2) high fidelity but complex algorithms customized to specific application-level metrics. Ideally, a solution should be both general (i.e., supports many applications) and provide accuracy comparable to custom algorithms. This paper presents UnivMon, a framework for flow monitoring which leverages recent theoretical advances and demonstrates that it is possible to achieve both generality and high accuracy. UnivMon uses an application-agnostic data plane monitoring primitive; different (and possibly unforeseen) estimation algorithms run in the control plane, and use the statistics from the data plane to compute application-level metrics. We present a proof-of-concept implementation of UnivMon using P4 and develop simple coordination techniques to provide a ``one-big-switch'' abstraction for network-wide monitoring. We evaluate the effectiveness of UnivMon using a range of trace-driven evaluations and show that it offers comparable (and sometimes better) accuracy relative to custom sketching solutions.

Vehicle Fuel-Efficiency Choices, Emission Externalities, and Urban Sprawl

Scipedia content — Tue, 02 Feb 2021 02:29:47 +0100

This paper shows that a city where both a congestion externality and an externality from greenhouse gas emissions are corrected by efficient policies is more compact than the laissez-faire equilibrium city. Motivated by recent empirical studies showing a positive relationship between population density and vehicle fuel-efficiency, the consumer is assumed to choose vehicle fuel-efficiency jointly with housing consumption and residential location. By incorporating the consumer׳s vehicle choice into the urban spatial model, we can represent the total amount of vehicle emissions released by the city residents. We first establish the well-known result that the congestion externality as a source of market failure is associated with excessive urban sprawl. We then show that vehicle emissions are an additional source of market failure, which also leads to excessive urban sprawl. The source of excessive sprawl arising from the emission externality is the use of larger and less-fuel efficient vehicles in more sprawled cities, which is different from that of the congestion externality. We also analyze the effect of the Corporate Average Fuel Economy (CAFE) standards on urban spatial structure and its efficacy as a second-best tool for correcting the emission externality.

Proactive and Reactive Management of Non-Weather Capacity Disruption Events in the National Airspace System: A Flow Modeling and Design Approach

Scipedia content — Tue, 02 Feb 2021 02:24:36 +0100

primary function of air traffic flow management is to strategically shape traffic demand to match capacities (e.g., airport arrival/departure rate limits and Sector capacities), without imposing excessive delay. In the current United States National Airspace System (NAS), the disruptions modulating capacities and hence traffic management are predominantly weather events, including convection, winter weather, and high winds. However, during the next 15 years and beyond, it is likely that the air traffic system will be increasingly subject to man-made disruptions that impact traffic management, including 1) a growing frequency of cyberand physical-world security incidents, 2) commercial space operations, and 3) integration of high-altitude unmanned aircraft. Disruptions of these types have already begun to impact traffic control and management: for instance, the insider attack on the Chicago Air Route Traffic Control Center (ZAU) communication equipment during October 2014, and several recent commercial space launches and UAS-integration test scenarios. To date, such non-weather disruptions have had relatively contained and limited impact on air traffic system operations, but they will undoubtedly incur greater impact and cost in the near future as the airspace system becomes increasingly heterogeneous and cyberenabled. In consequence, paradigms for traffic management that account for non-weather disruptions will be needed in the near future.

Application of groundwater aggressiveness assessment method for estimation of the karst process at main gas pipeline construction

Scipedia content — Tue, 02 Feb 2021 02:18:51 +0100

Main pipelines maintenance is connected with hazard engineering and geological working conditions. The article deals with the use of groundwater aggressiveness assessment method to estimate the karst processes development during the construction of main gas pipelines. The possibility of using this method is analyzed on the example of the initial section of the designed gas pipeline "Power of Siberia" (section "Chayanda-Lensk"). The calculation of the nonequilibrium index Ca was made in accordance with the geotechnical survey data. The dependencies between the geomorphological features of the terrain and the natural waters aggressiveness were determined.

Impact of wheel shape on the vertical damage of cast crossing panels in turnouts

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

Impact forces generated in the load transfer area of railway crossing panels lead to a range of degradation modes from wear and fatigue of the contacting materials, fatigue of supporting components to ballast/subgrade deterioration. A simplified modelling approach has been developed to first analyse the geometrical problem of the axle rolling through the crossing geometry, and in a second step to predict the vertical dynamic force produce from the interaction between the wheel unsprung mass and the track system. The force is analysed in the frequency domain to estimate the level of damage in different parts of the track system. A parametric analysis of wheel shapes was carried out showing that the axle lateral displacement has a significant influence on the produced level of damage and also that characteristics such as the wheel flange thickness and the equivalent slope in the area of contact also leads to increased damage. It is suggested that such a measure in combination with the simplified algorithms developed here could be used, possibly in combination with track side monitoring system, to highlight traffic instances leading to increased asset damage.

Development and Testing of a Post-Installable Deepwater Monitoring System Using Fiber-Optic Sensors

Scipedia content — Tue, 02 Feb 2021 02:14:10 +0100

This paper addresses the design and development of a fiber-optic monitoring system that can be deployed on existing deep water risers and flow lines; and provides a summary of test article fabrication and the subsequent laboratory testing performed at the National Aeronautics and Space Administration-Johnson Space Center (NASA-JSC)."/jats:p" "jats:p"A major challenge of a post-installed instrumentation system is to ensure adequate coupling between the instruments and the riser or flow line of interest. This work investigates the sensor coupling for pipelines that are suspended in a water column (from topside platform to seabed) using a fiber-optic sensor clamp and subsea bonding adhesive. The study involved the design, fabrication, and test of several prototype clamps that contained fiber-optic sensors. A mold was produced by NASA using 3-D printing methods that allowed the casting of polyurethane clamp test articles to accommodate 4-inch and 8-inch diameter pipes. The prototype clamps were installed with a subsea adhesive in a “wet” environment and then tested in the NASA Structures Test Laboratory (STL). The tension, compression, and bending test data showed that the prototype sensor clamps achieved good structural coupling, and could provide high quality strain measurement for active monitoring.

Bike sharing station placement leveraging heterogeneous urban open data

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

International audience; Bike sharing systems have been deployed in many cities to promote green transportation and a healthy lifestyle. One of the key factors for maximizing the utility of such systems is placing bike stations at locations that can best meet users' trip demand. Traditionally, urban planners rely on dedicated surveys to understand the local bike trip demand, which is costly in time and labor, especially when they need to compare many possible places. In this paper, we formulate the bike station placement issue as a bike trip demand prediction problem. We propose a semi-supervised feature selection method to extract customized features from the highly variant, heterogeneous urban open data to predict bike trip demand. Evaluation using real-world open data from Washington, D.C. and Hangzhou shows that our method can be applied to different cities to effectively recommend places with higher potential bike trip demand for placing future bike station

Design of an Autonomous Intelligent Demand-Side Management System by using Electric Vehicles as Mobile Energy Storage Units by Means of Evolutionary Algorithms

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

International audience; Evolutionary Algorithms (EAs), or Evolutionary Computation, are powerful algorithms that have been used in a range of challenging real-world problems. In this paper, we are interested in their applicability on a dynamic and complex problem borrowed from Demand-Side Management (DSM) systems, which is a highly popular research area within smart grids. DSM systems aim to help both end-use consumer and utility companies to reduce, for instance, peak loads by means of programs normally implemented by utility companies. In this work, we propose a novel mechanism to design an autonomous intelligent DSM by using (EV) electric vehicles' batteries as mobile energy storage units to partially fulfill the energy demand of dozens of household units. This mechanism uses EAs to automatically search for optimal plans, representing the energy drawn from the EVs' batteries. To test our approach, we used a dynamic scenario where we simulated the consumption of 40 and 80 household units over a period of 30 working days. The results obtained by our proposed approach are highly encouraging: it is able to use the maximum allowed energy that can be taken from each EV for each of the simulated days. Additionally, it uses the most amount of energy whenever it is needed the most (i.e., high-peak periods) resulting into reduction of peak loads.

HSR and tourism: what can we learn from the past 50 years?

Scipedia content — Tue, 02 Feb 2021 01:54:57 +0100

International audience; HSR and tourism: what can we learn from the past 50 years?Important investements in High Speed Rail (HSR) lines have been carried out all over the world since the opening of the first line in 1964. The analysis of the wider effects brought by these systems has been the core of major publications in the literature with the objective of investigating the benefits of the investments themselves.One aspect, less treated but of great interest, is the impact of HSR systems on the tourism market. Indeed, for an optimal assessment of this impact, some variables should be taken into account: firstly, how many tourists would not have gone to a given destination had the HSR not existed? Secondly, what are the characteristics of the tourists choosing to visit a destination served by a HSR line and what is the duration of their journey? ? Thirdly, do visitors spending justify the returns on investment?Some studies confirm that there is an impact, for example during the period between 1999 and 2010, the emerging HSR services did have significant impacts on boosting tourism in China. Provinces with HSR services were likely to have approximate 20% additional numbers of foreign arrivals and 25% greater tourism revenues than provinces without such systems (Chen and Haynes, 2012). But other authors show that it is not always the case in all the served cities (Todorovitch et al., 2011) and sometimes, a decrease of the journey has also been observed (Delaplace et al., 2014).The objective of this contribution is to show, through a literature review of studies carried out ex-post, that the effects are not systematic, since they depend on the implementation of the HSR service and on the characteristics of the places served. Indeed, if the HSR allows, in some cases, the increase in the number of tourists, a decrease of the length stay might follow. Some of the main findings of the scientific literature over the past 40 years are that the changes of accessibility of a destination served by a new HSR link is not the only element playing a role in tourism dynamism. It is necessary to take also into account the way HSR systems improve the image of the destination itself and the way they contribute to the coordination of the local stakeholders.

The effect of video caching on network resource planning — a real-case study

Scipedia content — Tue, 02 Feb 2021 01:48:46 +0100

Traffic Engineering is one of the building blocks for a correct network planning. Internet Service Providers are always trying to fulfill the user Quality of Experience (QoE). However, each technological advance brings new services to the user, with new challenges to be solved to maintain the QoE.

The Design of Signal Control Software and Intersection Traffic Simulation

Scipedia content — Tue, 02 Feb 2021 01:46:06 +0100

The current traffic signal lights often do not have flexible revise function, so it can't reach the real-time control requirements, and leads to increasingly serious urban traffic congestion, this control software presents an effective method to solve it by researching intersection traffic signal control. In this paper, intersection traffic signal timing control software and traffic flow microscopic simulation are designed. The software is implemented using the MFC programme. Simulation is based on SUMO. Through combining them, it can accomplish fixed timing control, multi-time control and adaptive control, which can adapt to different timing requirements and response to the current road conditions intuitively. By analyzing simulation result datas, it can be used for urban traffic signal timing optimization. To some degree, this software can ease the traffic congestion.

A Framework of Point Merge-based Autonomous System for Optimizing Aircraft Scheduling in Busy TMA

Scipedia content — Tue, 02 Feb 2021 01:42:10 +0100

International audience; In this article we present recent work towards the development of an autonomous system with point merge (PM) that performs sequencing, merging and spacing for arrival aircraft in the busy terminal area. This autonomous arrival management system aims to safely solve the major arrival flight scheduling problems currently handled by human controllers. With PM, it has the potential to handle higher traffic demands without more workload on controllers, consequently increasing capacity and reducing delay. The main objective of this paper is to introduce the framework of this autonomous system with PM. Based on analysis of classic PM route structure, a novel PM-based route network is firstly designed for Beijing Capital International Airport. Vertically, this PM system consists of multi-layers on the sequencing legs for different categories of aircraft with Heavy and Medium, horizontally, it is shaped as a lazy “8”. Then, a multiple-objectives function is discussed for this aircraft scheduling problem, operational constraints and conflict detection and resolution are analysed in detail, a modelling strategy with sliding time window and simulated annealing algorithm is proposed for solving this real-time dynamic problem. Experimental results verify our algorithm is well adapting the high-density traffic optimisation, and finally a conclusion is made and future work is pointed ou

Enabling a "RISC" Approach for Software-Defined Monitoring using Universal Streaming

Scipedia content — Tue, 02 Feb 2021 01:37:34 +0100

Network management relies on an up-to-date and accurate view of many traffic metrics for tasks such as traffic engineering (e.g., heavy hitters), anomaly detection (e.g., entropy of source addresses), and security (e.g., DDoS detection). Obtaining an accurate estimate of these metrics while using little router CPU and memory is challenging. This in turn has inspired a large body of work in data streaming devoted to developing optimized algorithms for individual monitoring tasks, as well as recent approaches to make it simpler to implement these algorithms (e.g., OpenSketch). While this body of work has been seminal, we argue that this trajectory of crafting special purpose algorithms is untenable in the long term. We make a case for a "RISC" approach for flow monitoring analogous to a reduced instruction set in computer architecture---a simple and generic monitoring primitive from which a range of metrics can be computed with high accuracy. Building on recent theoretical advances in universal streaming, we show that this "holy grail" for flow monitoring might be well within our reach.

Table of Content

Scipedia content — Tue, 02 Feb 2021 01:31:41 +0100

Table of Content Acta Cardiologia Indonesiana Volume 1 Number 1 Year 2015

Document type: Article

A Research on Prediction about Air passenger Traffic in the Capital Airport Area

Scipedia content — Tue, 02 Feb 2021 01:22:48 +0100

With the continuous development of China's economic level, the amount of air traffic has improved a lot. More and more airports are constructed or expanded in China. in order to avoid the waste of resources caused by too large-scale planning, prediction for air traffic has occupied a more and more important position. Based on the detailed analysis of factors affecting the air passenger traffic, combined with the use of SPSS13.0 software, we try to find out how these factors affect air traffic and how they affect each other. Some methods like trend extrapolation and linear regression analysis are also used in this paper. Considering all these factors together and using these methods mentioned above to get a final predict result.

Risk assessment of a petroleum product pipeline in Nigeria: the realities of managing problems of theft/sabotage

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

Pipelines carrying oil and gas are very safe forms of energy transportation, but they do sometimes fail. In the Developed World these failures are usually associated with impact damage (e.g. from earth moving equipment), corrosion, or manufacturing faults in the pipeline materials. In the Developing World theft and sabotage is a major, and increasing cause of failure. Countries such as China, Mexico, and Nigeria have major problems with theft of pipeline products, sabotage, and vandalism. This paper reviews pipeline failures in Nigeria, focusing on pipelines carrying hydrocarbon liquids. The review clearly shows that theft/sabotage is the major cause of failure to pipelines, and the recorded failure rates (0.35 per km-year) are well above failure rates reported on other pipeline systems around the world. Fatalities from pipeline failures range from 0.04 to 0.38 per km-yr, depending on the region in Nigeria. Additionally, on average, the operator of the pipeline system considered in this paper loses about $US100million/year due to these failures. This value does not consider the costs associated with payment of compensation, fines, environmental clean-ups, litigation, etc. The paper concludes with recommendations to improve pipeline safety systems to reduce these fatalities and costs.

SERVICE ISSUES: overview of electric vehicles use in Vietnam

Scipedia content — Tue, 02 Feb 2021 00:59:44 +0100

International audience; Due to the problems caused by the gasoline engine on the environment and people, the automotive industry has turned to the electrically powered vehicle. Electric Vehicles (EVs) such as electric two-wheelers and electric cars provide convenient local transportation and are becoming popular means of transport in Vietnam in recent years. Electric bicycles, electric motorbikes and electric cars appeared in Vietnam since the early 2000s and are growing very quickly. As of September 2015, Vietnam's EV market has grown to an estimated 2.5 million e-bike units and over 1000 electric cars. However, electric vehicles, as a competitive solution for green transportation, are yet to be bettered off. Lead poisoning, traffic accidents, lack of charging facilities, lack of policies and regulations to ensure safe and effective usage for a better environment and sustainability, in general are the elements that affect and restrain the further development of the Vietnamese market. In this paper, we present an overview of EV use in Vietnam, as well as the benefits and limitations of EV use, especially the many existing issues, and some recommendations to manage the development of these new modes of transport.

Simulating the Risks from Aircraft Debris to the Public on the Ground

Scipedia content — Tue, 02 Feb 2021 00:55:13 +0100

International audience; The International Civil Aviation Organisation (ICAO) identify an Airprox to be a situation in which, in the opinion of a pilot or air traffic services personnel, the distance between aircraft as well as their relative positions and speed have been such that the safety of the aircraft involved may have been compromised. These are relatively rare events but they must be reported and investigated in order to reduce future risks. Airprox investigations and similar studies into near-miss incidents focus on the risk to passengers and crew. They do not consider the impact of debris. This raises concerns when, for example, the Bijlmermeer crash led to the deaths of 39 people on the ground. This paper presents a system that was developed to simulate the risks from aircraft debris on ground-based infrastructures. The system was developed and validated with help from Airprox investigators. To this end, a User Centered Design process was applied; analysing the activities and needs of potential users from two European investigation agencies. The following pages present the key design decisions, provide insights into the development process and identify limitations with our existing system. The closing sections identify further applications of this approach and suggest areas for further work.

The experimental study on shear behavior of concrete I-shaped beam with web openings

Scipedia content — Tue, 02 Feb 2021 00:52:03 +0100

KEYWORD:Experimental study; Web openings;Concrete I-shaped beams;Annular stirrups;Shear behavior ABSTRACT:Openings on the I-shaped beam web could accommodate pipelines and therefore might cut down the project cost due to the floor height is lower. In this paper, three concrete I- shaped beams are prepared, the sole difference between their is the openings position on the beam web. To compensate the strength undermined by the openings, annular stirrups are added to the surroundings of the openings. Then, based on these preparation works, a series of experiments were carried out to test the shear behavior of the beams and obtain relevant data, such as deflection, crack width and distribution, strain of reinforcing steel. Data analyses were made according to the statistics collected from the experiments what testified the feasibility of extending the opening at the beam web's ends. Some useful proposals about how to decide the bar amounts of annular stirrups also given by this work.

Estimation and back extrapolation of CO2emissions from the road transport sector: emissions in Ireland, 1990 to 2013

Scipedia content — Tue, 02 Feb 2021 00:49:58 +0100

The estimation of CO2 emissions is an important information process in the assessment of climate impacts, mitigation policy development, and assessment of the impacts of previous interventions in various polluting sectors. This investigation comprised the estimation of CO2 emissions from the road transport sector in Ireland using a previously unavailable level of data disaggregation for vehicle mileage as well as using vehicle class specific data and an improved estimation methodology. Estimates of CO2 emissions were carried out for the recent years up to 2013 and these were also back extrapolated to 1990. CO2 emissions were estimated using COPERT software. Historic vehicle fleet data were restructured, annual mileage data were estimated and back extrapolated using a linear regression approach. The results of this investigation outline the distribution of CO2 emissions across the transport sector in Ireland in 2013. These results also facilitate a comparison of the impacts of the new input data and improved estimation methodology over previous estimates of CO2 emissions. Previous assessments (1990–2012) were shown to have under-estimated the contribution of diesel fuelled passenger cars by more than 38%. Diesel fuelled passenger cars were also shown to account for the majority of CO2 emissions from road transport activities in Ireland in 2013.The results of this investigation highlight the impact of recent trends of increasing numbers of diesel car purchases in Ireland, which has been incentivised by government climate change policy.

Sustainable transport in cities: learning from best and worst practice?

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

It is generally recognized that a shift from car use to public transport, walking and cycling will reduce both local and global emissions. The goal of this paper was firstly to identify the European cities with the lowest and the highest car use, and secondly, to discuss if and how other cities can learn from the Best and Worst practice. The top twenty of cycling cities in Europe is presented. Munster in Germany tops the list and is the European Bike City. The new TEMS EPOMM database makes it easy to compare a modal split in cities and thus answer questions like: Which city is most transport sustainable? Which city is the most car dependent? It is not surprising that they cycle a lot in Dutch cities, nor in Copenhagen, possibly more surprising that the bike is used extensively in Berlin? Milton Keynes has indeed become a car city, 75 percent of all trips is with a car. A line can be drawn through Europe. North of the line one find “cycling countries” and south of the line “car countries”. Belgium is divided in two. Cities in the Flemish part to the north cycle a lot, while in Valona they hardly cycle. The paper discusses some of the findings and gives tentative answers to these differences between countries and citie

Spatial and Temporal Analysis of Mismatch between Planned Road Infrastructure and Traffic Demand in Large Cities

Scipedia content — Tue, 02 Feb 2021 00:38:18 +0100

large cities evolve in time, the traffic demand and the road network adapt to the mutually presented changes by each other. As a result of this process, previously planned roads and intersections that were designed according to some optimality criteria at the time, turn out to be sub-optimal when traffic conditions change. This paper presents a method that can be used in order to identify intersections whose capacity is no longer in correspondence with the demand of vehicles on them and the choices agent make at those locations. Using real data from a survey describing the travel patterns of people in the city of Singapore we are able to model the routing choices of commuters and simulate the traffic demands on the road network. After calculating the turning probabilities on every intersection we are able to compare the traffic demand for every turn with the planned physical roads' capabilities. Furthermore we define a measure, which quantifies the deviation of the whole road network from the ideal demand-calculated values. We use these measures to evaluate the temporal and spatial profile of the mismatch between the roads and the demand for them. The measure is designed such that it is universal in nature and invariant to the absolute values of the traffic flows in the city. It can, therefore, be used to compare the proper utilization of road networks among different cities.

Programming sensor networks with nomadic NFC transponders

Scipedia content — Tue, 02 Feb 2021 00:26:43 +0100

We present how NFC transponders can be used for energy efficient programming of closed-loop sensor networks, to update or augment the existing functionality. Use cases include road tunnel inspection, water pipeline monitoring and maintaining safety information on behalf of mine workers. We utilize opportunistic movement of the human operator, the flow of fluid in a pipeline or material in mines, to move the NFC transponder in the system effortlessly and without external network connectivity. Transponders contain mobile agents in their memory, which are injected into the system when transponder comes to the proximity of a node with NFC reader component. Then mobile agents autonomously operate their tasks, i.e. collect and process sensor data in the devices, detect events from data, control physical components and report their results. Mobile agents can adapt to the operational conditions of the system and physical environment, e.g. to save energy or operate in isolated network segments in fault situations. Real-world evaluation shows that this method is energy efficient in comparison with communications atop similar wireless sensor network.

Moving Vehicles Detection Based on Improved Gaussian Mixture Model

Scipedia content — Tue, 02 Feb 2021 00:25:10 +0100

Vehicles detection has a great significance on traffic congestion relief, traffic accidents prevention and treatment. This paper proposes an improved Gaussianmixture model(GMM) to detect moving vehicles because GMM always detects background for foreground in complex environment. The new algorithm combines GMM with frame difference. Then, the whole vehicle can be detected by this new algorithm because of the enhanced demarcation point between background and foreground. Finally, the moving vehicles detection system is established. Experiments in different weather(sunny and rainy) and different time(day and night) have been made. They can prove that the new algorithm has been greatly improved in the aspects of adaptability, accuracy, real-time and so on. The movingvehicles can also be detected correctly and effectively in the situation with various complicated factors.

Numerical simulation and pressure drop prediction of slug flow in oil/gas pipelines

Scipedia content — Tue, 02 Feb 2021 00:24:34 +0100

The sustainable transportation of liquid fuels in a piping system can be interrupted due to slug flow, which causes the severe unsteady loading on pipelines. A feature that is particularly affected by this problem is the oil transportation pipeline, where gas is often combined with the produced oil. In order to fully understand the behavior of such flows, it is imperative to simulate the effective zones along the span of the pipelines. This will allow the designer of the piping system to estimate the required pumping power through the evaluation of the pressure drop in the slug oil/gas flow. This paper reports the oil/gas flow phenomena in a horizontal pipe with a large diameter of 0.16 m, with 3-dimensional, transient, incompressible fluids, utilizing STAR-CCM+ commercial software. The volume of fluid (VOF) model was adopted to track the interface between the two phases. The operational conditions for the cases studied were extracted for the slug zone from the Baker chart. The slug flow was achieved accordingly, which gives us granted validation with the experimental source. The numerical procedure allowed the determination of the pressure drop. Also, the transient behavior of the slug flow was predicted through the tracking of the slug development in the pipe segment. Moreover, the proposed model could be extended to simulate other types of two-phase flow regimes.

An Intersection Game-Theory-Based Traffic Control Algorithm in a Connected Vehicle Environment

Scipedia content — Tue, 02 Feb 2021 00:23:01 +0100

Urban traffic congestion is a growing problem that we experience every day. Intersections are one of the major bottlenecks that contribute to urban traffic congestion. Traditional traffic control methods, such as traffic signal and stop sign control are not optimal for all demand levels as demonstrated in the literature. Recently, numerous research efforts proposed Intelligent Transportation System (ITS) applications to enhance intersection capacity and hence reduce congestion. In this paper we propose a game-theory-based algorithm for controlling autonomous vehicle movements equipped with Cooperative Adaptive Cruise Control (CACC) systems at uncontrolled intersections. The goal of this research effort is to develop an algorithm capable of using the future autonomous/automated vehicle capabilities to replace the usual state-of-the-practice control systems at intersections (e.g. stop signs, traffic signals, etc.). The proposed algorithm is chicken-game inspired and is efficient for application in real-time. It assumes vehicles can communicate with a central agent at the intersection to provide their instantaneous speeds and locations. The proposed algorithm assumes that vehicles obey the Nash equilibrium solution of the game. The simulation results demonstrated reductions in vehicle travel time and delay relative to an all-way stop sign control in the range of 49 and 89 percent on average respectively.

Luxembourg SUMO Traffic (LuST) Scenario: 24 hours of mobility for vehicular networking research

Scipedia content — Tue, 02 Feb 2021 00:21:55 +0100

Different research communities varying from telecommunication to traffic engineering are working on problems related to vehicular traffic congestion, intelligent transportation systems, and mobility patterns using information collected from a variety of sensors. To test the solutions, the first step is to use a vehicular traffic simulator with an appropriate scenario in order to reproduce realistic mobility patterns. Many mobility simulators are available, and the choice is usually done based on the size and type of simulation required, but a common problem is to find a realistic traffic scenario. In order to evaluate and compare new communication protocols for vehicular networks, it is necessary to use a wireless network simulator in combination with a vehicular traffic simulator. This additional step introduces further requirements for the scenario. The aim of this work is to provide a scenario able to meet all the common requirements in terms of size, realism and duration, in order to have a common basis for the evaluations. In the interest of building a realistic scenario, we decided to start from a real city with a standard topology common in mid-size European cities, and real information concerning traffic demands and mobility patterns. In this paper we show the process used to build the Luxembourg SUMO Traffic (LuST) Scenario, and present a summary of its characteristics together with an overview of its possible use cases.

Distributed traffic control for reduced fuel consumption and travel time in transportation networks

Scipedia content — Tue, 02 Feb 2021 00:12:17 +0100

This paper proposes a distributed framework for optimal control of vehicles in transportation networks. The objective is to reduce the balanced fuel consumption and travel time through hybrid control on speed limit and ramp metering rate. The dual decomposition theory associated with the subgradient method is then applied in order to decompose the optimal control problem into a series of suboptimal problems and then solve them individually via networked road infrastructures (RIs). Coordination among connected RIs is followed in each iteration to update the individual controls. An example is demonstrated to verify the reduction in terms of fuel consumption and travel time using the proposed approach.

Engineering Oracles for Time-Dependent Road Networks

Scipedia content — Tue, 02 Feb 2021 00:11:30 +0100

We implement and experimentally evaluate landmark-based oracles for min-cost paths in large-scale time-dependent road networks. We exploit parallelism and lossless compression, combined with a novel travel-time approximation technique, to severely reduce preprocessing space and time. We significantly improve the FLAT oracle, improving the previous query time by $30\\%$ and doubling the Dijkstra-rank speedup. We also implement and experimentally evaluate a novel oracle (HORN), based on a landmark hierarchy, achieving even better performance wrt to FLAT.

Comment: In ALENEX 2016

A City Traffic Library

Scipedia content — Tue, 02 Feb 2021 00:07:33 +0100

Digital Product Simulation (DPS) created a library for the modeling of city traffic. This library is designed for the development and evaluation of control strategies, rendered possible when vehicles are able to communicate between each other and with their infrastructure. CityTraffic library allows for the implementation of control strategies by all of the players acting in an urban environment (e.g. located in vehicles, with a global server computing set points for the vehicles, or with a traffic management system setting speed limits and traffic light cycles). The library is divided in two parts, macroscopic traffic and microscopic traffic. Macroscopic components are used to describe road networks such as highways whereas microscopic components allow for modeling city traffic where interactions between vehicles and their environment are many. By using a City Traffic library, cities can decrease the number of traffic jams on their road network, and improve the overall impact of the traffic on the environment.

Transport and traffic rule violation monitoring service in ITS: A secured VANET cloud application

Scipedia content — Tue, 02 Feb 2021 00:04:06 +0100

Vehicular Ad-hoc Network (VANET) cloud, a hybrid technology, provides several computational services to minimize traffic congestion, travelling time, accidents, and environmental pollution. In the proposed work, the concept of VANET cloud is used for helping the regulatory authorities in identifying the vehicles violating the traffic rules through sensors included as part of On Board Unit (OBU). When the vehicle is on fly the sensor values are periodically transferred to the cloud, controlled by the traffic police. A novel concept called Transient Ticket (TT) has been used to minimize the time and the cost of distributing Certificate Revocation List (CRL) to the vehicles. The proposed scheme also ensures utmost verification of identity, authenticity, confidentiality and integrity of the communication parties and messages exchanged. The work has been simulated using NS3 network simulator and Google App Engine (GAE). All the generated keys, TTs and the exchanged messages have been securely stored in the GAE for the ease of accessibility and processing. The results show that the proposed approach consumes very less time with respect to the generation of keys, exchange of messages, verification of authenticity and the generation of TT without compromising security.

The design of an agent based model of human activities and communications in cardiac resuscitation

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

International audience; Cardio-pulmonary arrest is a common emergency situation causing over 400,000 deaths per year, more than a 1000 per day, in the USA alone. The goal of this work is to develop an agent based computer simulator that will allow trainers to experiment with different communication protocols, such as those found in air traffic control. This paper describes the first step in designing the simulator development. The design is based on an analysis of communications during real life training simulations using the FIPA standard categories.

Protecting Offshore Pipelines Against Drifting Ice: A Discussion on Standards and Guidelines

Scipedia content — Mon, 01 Feb 2021 23:59:21 +0100

In freezing waters, seabed gouging ice features (icebergs, pressure ridges) are a threat to offshore pipelines, which must be buried to a safe depth. Several standards and guidelines addressing this issue are examined and compared. The type of information that each code deems significant varies considerably — factors that are important to some code writers are not to others. API RP 2N, CSA-ISO 19906, CSA Z662 and DNV OS F101 direct the users to specific factors that either must or could be considered for design, but do not indicate what is to be done with them. In contrast, the RMRS rules are highly prescriptive. From a code user’s perspective, a comprehensive listing of all factors involved in ice-seabed-pipe interaction might provide better guidance in assessing what needs to be considered. This assessment could also be divided into three distinct operations: determination of design gouge depth, determination of clearance below the design gouge depth, and determination of pipeline response.Copyright © 2015 by Her Majesty the Queen in Right of Canad

JChoc DisSolver - Bridging the Gap Between Simulation and Realistic Use

Scipedia content — Mon, 01 Feb 2021 23:58:49 +0100

The development of innovative and intelligent multiagent applications based on Distributed Constraints Reasoning techniques is obviously a fastidious task, especially to tackle new combinatorial problems (e.i. distributed resource management, distributed air traffic management, Distributed Sensor Network (Bejar et al., ´ 2005)). However, there are very few open-source platforms dedicated to solve such problems within realistic uses. Given the difficulty that researchers are facing, simplifying assumptions and simulations uses are commonly used techniques. Nevertheless, these techniques may not be able to capture all the details about the problem to be solved. Hence, transition from the simulation to the actual development context causes a loss of accuracy and robustness of the applications to be implemented. In this paper, we present preliminary results of a new distributed constraints programming platform, namely JChoc DisSolver. Thanks to the extensibility of JADE communication model and the robustness of Choco Solver, JChoc brings a new added value to Distributed Constraints Reasoning. The platform is user-friendly and the development of multiagent applications based on Constraints Programming is no longer a mystery to users. A real distributed problem is used to illustrate how the platform can be appropriated by an unsophisticated user and the experimental results are encouraging for more investigations.

Green transportation analysis based on environmental logistics in China

Scipedia content — Mon, 01 Feb 2021 23:57:45 +0100

Objective: emphasizing preventing the environment from being harmed by logistics, Then he analyses green transportation of the environmental logistics study.especially on the part of possible degree in china. Methods: Survey Analysis based on status of China. Results: Chinese people believe that at this stage the logistics of low prices for the realization of the higher cost of environment logistics, most people are willing to pay a higher cost, but China's current energy structure and the technical level is difficult to achieve in a short leap. Conclusion: Although green transport is extremely important in a ring of environmental logistics, it's the reality of today's China is difficult to significant improvement in

Assessing people travel behavior using GPS and open data to validate neighbourhoods characteristics

Scipedia content — Mon, 01 Feb 2021 23:52:22 +0100

With the help of technologies such as GPS tracks, GIS and open data is now possible to study people travel behaviour in a new way. Nowadays, large datasets can be easily handled thanks to databases and better visualized using GIS. Moreover, the availability of GPS data, open data and VGI makes accessible a lot of new information, which was not obtainable before. This research is about the analysis of mobility patterns in different neighbourhoods in three cities in the Netherlands. The study is based on the validation of mobility theoretical performances by the actual performances measured through the analysis of GPS logs of households, who live in the neighbourhoods. A series of spatial indicators based on proximity, density and accessibility are computed in order to assess the theoretical performances of the neighbourhoods. To achieve this task, information about built environment characteristics and infrastructure networks is retrieved from OpenStreetMap, and other datasets. In the end the neighbourhoods are classified into five classes, according to the different levels of performances in terms of sustainable mobility. In such a way, it is possible to better understand the key factors that influence actual people travel patterns, providing policy makers with accurate information about the real movement of people.

Modulating Workload for Air Traffic Controllers during Airport Ground Operations

Scipedia content — Mon, 01 Feb 2021 23:48:36 +0100

International audience; Evaluating future technology concepts for air traffic control ground operations requires exploration of work scenarios of differing complexities, i.e. scenarios that create more or less taskload for air traffic controllers. While the link between traffic load and workload has been well-characterized in the literature and is often the only complexity variable applied to validation studies, there are other operational events that can augment controller workload. Through a series of interviews and on-site observations of professional and student air traffic controllers, we defined seven general operational events that can be applied to all airport ground operations. We discuss the development of two scenarios of different workloads (average and hard) and their validation with air traffic controllers.

PMSR - Poor Man's Segment Routing, a minimalistic approach to Segment Routing and a Traffic Engineering use case

Scipedia content — Mon, 01 Feb 2021 23:43:18 +0100

The current specification of the Segment Routing (SR) architecture requires enhancements to the intra-domain routing protocols (e.g. OSPF and IS-IS) so that the nodes can advertise the Segment Identifiers (SIDs). We propose a simpler solution called PMSR (Poor Man's Segment Routing), that does not require any enhancement to routing protocol. We compare the procedures of PMSR with traditional SR, showing that PMSR can reduce the operation and management complexity. We analyze the set of use cases in the current SR drafts and we claim that PMSR can support the large majority of them. Thanks to the drastic simplification of the Control Plane, we have been able to develop an Open Source prototype of PMSR. In the second part of the paper, we consider a Traffic Engineering use case, starting from a traditional flow assignment optimization problem which allocates hop-by-hop paths to flows. We propose a SR path assignment algorithm and prove that it is optimal with respect to the number of segments allocated to a flow.

Comment: September 2015 - Paper accepted to the Mini-conference track of NOMS 2016

Mechanism based on pipe cleaning apparatus of high-pressure water jet

Scipedia content — Mon, 01 Feb 2021 23:34:14 +0100

Industrial pipes conveying fluid in the long process will produce dirt, which affects the efficiency of transmission. This paper presents a design applicable to pipeline clean-up program. The use of high pressure rotating nozzle head is designed to use high-pressure water jet to clean up the striking force pipeline. This paper also proposes a clamping force relies on two cams to constrain pipes. The coordination with the two cams control the speed and mode of high-pressure pipes to to apply to different pipe scale. And the design of adaptive spring system accommodates different diameter high-pressure transmission pipes. Experimental results demonstrate the effectiveness of pipeline cleaning device based on high pressure water jet. Introduction Pipeline in the chemical business has been very widely used, mainly used to transport chemical raw materials and chemical liquid. The long-time delivery will lead to the chemical liquid remaining in the pipeline, which greatly reduces the effective portion of the pipeline, seriously affects the transmission efficiency and increases costs, so that the pipelines need to clean in times. According to the current domestic and international existing high-pressure water jet control scheme, this paper proposes a high-pressure water jet pipe cleaning solution for factories. The use of high pressure rotating nozzle head is designed to use high-pressure water jet to clean up the striking force pipeline. The coordination with the two cams control the speed and mode of high-pressure pipes to apply to different pipe scale. And the design of adaptive spring system accommodates different diameter high-pressure transmission pipes. The device is designed to solve the inconvenience to clean up the vertical pipe, and the problems of horizontal pipes’ incomplete clean. Overall high-pressure injection system design and demonstration. According to the equation 0.745 F q p  about water jet (q is the flow per minute through the water, unit L / min, p is the pressure of the water jet, unit Mpa). The design specifications required of climbing height lead to calculate the pressure and flow pressure, and then adjust the high-pressure pipe nozzle spray angle to achieve the best cleaning effect. Using high-pressure rotating nozzle head, followed by a row of nozzle orifices with a set angle trunk, high-pressure hose connected to the tail through thread. Legs and high pressure nozzle body joints using a torsion spring. The upper legs fit with a large number of small roller. When facing the diameter transformation, torsion springs compress, so that the legs can be shorter to adjust the diameter changing pipeline. The model of high-pressure rotating nozzle head shows in figure 1. 5th International Conference on Information Engineering for Mechanics and Materials (ICIMM 2015) © 2015. The authors Published by Atlantis Press 169 Fig.1 High-pressure rotating nozzle head model Whether the high pressure hose can go through the variable diameter pipeline, the key point is the choice of torsion stiffness. Figure 2 shows some parameters of a torsion spring in large diameter pipe to a small diameter pipe transition state of motion. The analysis of Adams in which the transition from the high-pressure nozzle is designed to process large diameter pipes of small diameter, the role of time and the tail thrust related to the relatively short duration of action. So you can draw a conclusion that the designs of high pressure nozzle thrust can go through varying-diameter pipelines. (a) Torsion spring x direction velocity (b) Torsion spring deformation (c) Torsion spring torque diagram Fig.2 Torsion spring in the variable diameter pipeline motion state diagram To achieve climbing height, high-pressure rotating nozzle head needs to overcome its own gravity and hose gravity. According to 0.745 F q p  , get a group of theoretical value of the pressure and flow rate, the relationship shown in Figure 3. And then according to the theoretical value for the selected motor, and finally a combination of a high pressure injection control system is completed. Fig.3 Water jets striking force ,pressure and flow diagrams Design and implementation of high-pressure hose’s speed-control mechanism Thread screw goes through the hole between the frame and the support plate on the threaded connection. Since the box is fixed, when knobbing screw thread, the thread-support plate will move along the direction of the screw. There are two limit stops on the front end of the movement plate, thereby pressing the spring and the movement plate. The roller mounting shaft passing through the

A Software Stack for Next-Generation Automotive Systems on Many-Core Heterogeneous Platforms

Scipedia content — Mon, 01 Feb 2021 23:21:39 +0100

The advent of commercial-of-the-shelf (COTS) heterogeneous many-core platforms is opening up a series of opportunities in the embedded computing market. Integrating multiple computing elements running at lower frequencies allows obtaining impressive performance capabilities at a reduced power consumption. These platforms can be successfully adopted to build the next-generation of self-driving vehicles, where Advanced Driver Assistance Systems (ADAS) need to process unprecedently higher computing workloads at low power budgets. Unfortunately, the current methodologies for providing real-time guarantees are uneffective when applied to the complex architectures of modern many-cores. Having impressive average performances with no guaranteed bounds on the response times of the critical computing activities is of little if no use to these applications. Project HERCULES will provide the required technological infrastructure to obtain an order-of-magnitude improvement in the cost and power consumption of next generation automotive systems. This paper presents the integrated software framework of the project, which allows achieving predictable performance on top of cutting-edge heterogeneous COTS platforms. The proposed software stack will let both real-time and non real-time application coexist on next-generation, power-efficient embedded platform, with preserved timing guarantees.

As a Sustainable Transportation Issue Evaluation Of Dolmush Taxi Transition in Bursa Turkey

Scipedia content — Mon, 01 Feb 2021 23:21:10 +0100

Aircraft trajectory clustering techniques using circular statistics

Scipedia content — Mon, 01 Feb 2021 23:13:08 +0100

This paper presents a statistical aircraft trajectory clustering approach aimed at discriminating between typical manned and expected unmanned traffic patterns. First, the track angle history for each trajectory is re-sampled and modelled using a mixture of Von Mises distributions (circular statistics). Second, the re-modelled trajectories are globally aligned using tools from bio-informatics. Third, the alignment scores are used to cluster the trajectories using an iterative k-medoids approach and an appropriate distance function. The approach is then evaluated using synthetically generated unmanned aircraft flights combined with real air traffic position reports taken over a sector of Northern Queensland, Australia. Results suggest that the technique is useful in distinguishing between expected unmanned and manned aircraft traffic behaviour, as well as identifying some common conventional air traffic patterns. Refereed/Peer-reviewed

Modelling flexible thrust performance for trajectory prediction applications in ATM

Scipedia content — Mon, 01 Feb 2021 23:06:29 +0100

Reduced thrust operations are of widespread use nowadays due to their inherit benefits for engine conservation. Therefore, in order to enable realistic simulation of air traffic management (ATM) scenarios for purposes such as noise and emissions assessment, a model for reduced thrust is required. This paper proposes a methodology for modelling flexible thrust by combining an assumed temperature (AT) polynomial model identified from manufacturer take-off performance data and public thrust models taken from typical ATM performance databases. The advantage of the proposed AT model is that it only depends on the take-off conditions —runway length, airport altitude, temperature, wind, etc. The results derived from this methodology were compared to simulation data obtained from manufacturer’s take-off performance tools and databases. This comparison revealed that the polynomial model provides AT estimations with sufficient accuracy for their use in ATM simulation. The Base of Aircraft Data (BADA) and the Aircraft Noise and Performance (ANP) database were chosen as representative of aircraft performance models commonly used in ATM simulation. It was observed that there is no significant degradation of the overall accuracy of their thrust models when using AT, while there is a correct capture of the corresponding thrust reduction.

Peer Reviewed

Decentralized Control for Scalable Quadcopter Formations

Scipedia content — Mon, 01 Feb 2021 23:05:35 +0100

An innovative framework has been developed for teamwork of two quadcopter formations, each having its specified formation geometry, assigned task, and matching control scheme. Position control for quadcopters in one of the formations has been implemented through a Linear Quadratic Regulator Proportional Integral (LQR PI) control scheme based on explicit model following scheme. Quadcopters in the other formation are controlled through LQR PI servomechanism control scheme. These two control schemes are compared in terms of their performance and control effort. Both formations are commanded by respective ground stations through virtual leaders. Quadcopters in formations are able to track desired trajectories as well as hovering at desired points for selected time duration. In case of communication loss between ground station and any of the quadcopters, the neighboring quadcopter provides the command data, received from the ground station, to the affected unit. Proposed control schemes have been validated through extensive simulations using MATLAB®/Simulink® that provided favorable results.

Document type: Article

Loading/unloading lay-by areas location and sizing: a mixed analytic-Monte Carlo simulation approach

Scipedia content — Mon, 01 Feb 2021 23:04:54 +0100

The already significant volume of freight vehicles moving within city limits is steadily growing, and is expected to continue increasing at an even faster rate. Many European cities, however, have historical urban heritages and constraints that make them a logistics nightmare, where traffic congestion can result from improperly parked vehicles. In this paper, we focus on the location and sizing of commercial parking lay-bys in urban centres, where it is possible to park for a limited amount of time to perform loading/unloading operations and deliveries. The problem has been formulated and addressed with reference to a central district in the city of Bergamo, with a strong commercial presence, and characterized by significant problems of traffic congestion. We present a mixed analytic-Monte Carlo simulation approach in order to find an optimal distribution and relative sizes of the lay-by areas according to the demand and location of the business activities.

Initial Analysis of and Predictive Model Development for Weather Reroute Advisory Use

Scipedia content — Mon, 01 Feb 2021 22:58:23 +0100

In response to severe weather conditions, traffic management coordinators specify reroutes to route air traffic around affected regions of airspace. Providing analysis and recommendations of available reroute options would assist the traffic management coordinators in making more efficient rerouting decisions. These recommendations can be developed by examining historical data to determine which previous reroute options were used in similar weather and traffic conditions. Essentially, using previous information to inform future decisions. This paper describes the initial steps and methodology used towards this goal. A method to extract relevant features from the large volume of weather data to quantify the convective weather scenario during a particular time range is presented. Similar routes are clustered. A description of the algorithm to identify which cluster of reroute advisories were actually followed by pilots is described. Models built for fifteen of the top twenty most frequently used reroute clusters correctly predict the use of the cluster for over 60 of the test examples. Results are preliminary but indicate that the methodology is worth pursuing with modifications based on insight gained from this analysis.

Virtual flight testing in an aircraft sizing and optimization process

Scipedia content — Mon, 01 Feb 2021 22:54:13 +0100

The approach proposed in this paper aims at increasing knowledge during the conceptual design phase through the addition of new modules or disciplines. Various investigations identified the Stability Augmentation System as a key subsystem to be taken into account as soon as possible since it opens the design space and allows potential performance gains. In parallel, studies demonstrated the strong impact of certification constraints on the sizing of an aircraft. A new Multi Disciplinary Analysis and Optimization process for conceptual studies is then defined. One of its characteristics is that a certification module corresponding to a digital version of the regulatory texts can exchange with the Multi Disciplinary Analysis during the optimization. With such a layout, designers can optimize a configuration given a set of constraints or, they can trace the necessary modifications to the certification rules for a given architecture. Another key feature of the proposed process is the use of a full simulator (6 degrees of freedom) to fly the various reference missions within the sizing process. With this approach aircraft designers have then a high fidelity mission module that provides an important amount of information. Potential benefits can be foreseen for advanced concepts (especially flying technology demonstrators) relying on energy sources other that kerosene. In addition, the possibility to simulate the real routes of the aircraft during the optimization phase opens many options for close collaborations with Air Traffic Management research. Of course, this amount of information comes at a certain computational cost that is unusual for conceptual design tools. However, there are already ideas on how to reduce computational time.

Underground pipeline laying using the pipe-in-pipe system

Scipedia content — Mon, 01 Feb 2021 22:52:54 +0100

The problems of resource saving and environmental safety during the installation and operation of the underwater crossings are always relevant. The paper describes the existing methods of trenchless pipeline technology, the structure of multi-channel pipelines, the types of supporting and guiding systems. The rational design is suggested for the pipe-in-pipe system. The finite element model is presented for the most dangerous sections of the inner pipes, the optimum distance is detected between the roller supports.

Suboptimal longitudinal reference trajectory computation for time based continuous descent operations

Scipedia content — Mon, 01 Feb 2021 22:47:12 +0100

This paper addresses a specific aspect of air traffic control services, namely the achievement of an orderly and expeditious flow of air traffic under time constrained continuous descent approach. More specifically, a futuristic 4D trajectory application where the air traffic controller will ask an aircraft to overfly a meter fix at a specific time is addressed. The main benefit expected from this application is to improve flight efficiency by more precise maneuvering resulting from on-board capabilities as well as noise abatement and fuel saving. More precise maneuvers are also expected to increase sector capacity. Indeed moving from radar vectoring to monitoring precomputed trajectories would contribute to decrease controller's workload and therefore to increase sector capacity. This paper presents a new methodology to compute a reference trajectory for time based continuous descent operations and focuses on aircraft longitudinal motion including known wind. As far as time constrained operations are assumed, final time as well as final altitude and along track distance to be flown are imposed. We propose a new methodology to compute a reference calibrated airspeed (CAS) and a reference vertical speed to achieve imposed final position and altitude at a prescribed time which solve the Two-point Boundary Value Problem (TPBVP) where initial and final constraints are coupled with the set of ordinary differential equations associated with the aircraft motion. The aircraft is considered as a point mass model. The optimal control problem consists in minimizing fuel consumption while ensuring that the maximum longitudinal and normal accelerations remain lower than the acceptable level for civil flights. The computed trajectory is a time parametrized trajectory which will be used as a reference trajectory by some envisioned tracking controller installed on board the aircraft. Nevertheless the design of the tracking controller is out of the scope of this paper. Numerical simulations using Bada 3.11 9 are provided to illustrate the suboptimal trajectory generation method and achieved results.

Optimal routing of electric vehicles in networks with charging nodes: A dynamic programming approach

Scipedia content — Mon, 01 Feb 2021 22:42:43 +0100

Motivated by the significant role of recharging in battery-powered vehicles, we study the routing problem for vehicles with limited energy through a network of charging nodes. We seek to minimize the total elapsed time for vehicles to reach their destinations considering both traveling and recharging times at nodes when the vehicles do not have adequate energy for the entire journey.We have studied the case of homogeneous charging nodes in [1] and generalized it to inhomogeneous charging nodes in [2] by formulating and solving a Mixed Integer Non-Linear Programming problem (MINLP) for a single-vehicle. In this paper, we solve the same problem using Dynamic Programming (DP), resulting in optimal solutions with lower computational complexity compared to [2]. For a multi-vehicle problem, where traffic congestion effects are included, we use a similar approach by grouping vehicles into “subflows” and propose a DP formulation. Our numerical results show that DP becomes prohibitively slow as the number of subflows increases. As in [1] and [2] we resort to an alternative flow optimization formulation leading to a computationally simpler problem solution with minimal loss of accuracy.

Perceived Accessibility of Public Transport as a Potential Indicator of Social Inclusion

Scipedia content — Mon, 01 Feb 2021 22:36:47 +0100

Perceived accessibility has been acknowledged as an important aspect of transport policy since the 70s. Nevertheless, very few empirical studies have been conducted in this field. When aiming to improve social inclusion, by making sustainable transport modes accessible to all, it is important to understand the factors driving perceived accessibility. Unlike conventional accessibility measures, perceived accessibility focuses on the perceived possibilities and ease of engaging in preferred activities using different transport modes. We define perceived accessibility in terms of how easy it is to live a satisfactory life with the help of the transport system, which is not necessarily the same thing as the objective standard of the system. According to previous research, perceived accessibility varies with the subjectively-rated quality of the mode of transport. Thus, improvements in quality (e.g. trip planning, comfort, or safety) increase the perceived accessibility and make life easier to live using the chosen mode of transport. This study (n=750) focuses on the perceived accessibility of public transport, captured using the Perceived Accessibility Scale PAC (Lättman, Olsson, & Friman, 2015). More specifically, this study aims to determine how level of quality affects the perceived accessibility in public transport. A Conditional Process Model shows that, in addition to quality, feeling safe and frequency of travel are important predictors of perceived accessibility. Furthermore, elderly and those in their thirties report a lower level of perceived accessibility to their day-to-day activities using public transport. The basic premise of this study is that subjective experiences may be as important as objective indicators when planning and designing for socially inclusive transport systems.

Economic and CO2 Emission Benefits of a Solar Powered Electric Vehicle Charging Station for Workplaces in the Netherlands

Scipedia content — Mon, 01 Feb 2021 22:29:32 +0100

The paper analyses the economic and environmental benefits of charging electric vehicles (EV) at workplaces in the Netherlands using photovoltaic panels (PV). A 10kW EV-PV charging system is used to charge the electric cars directly from photovoltaic panels. The cost of using a gasoline vehicle is compared with that of an electric vehicle that is charged from the grid or from solar panels. It is found that charging EV from PV results in huge savings in fuel cost, taxes and lower CO2 emissions. A comparison is made for solar panels installed on rooftops and as a solar carport and the impact of feed-in tariffs on PV generation revenues is evaluated.

Global earthing systems: Characterization of buried metallic parts

Scipedia content — Mon, 01 Feb 2021 22:15:47 +0100

International Standards IEC 61936-1 and EN 50522 define a Global Earthing System (GES) as the earthing network, created by the interconnection of local earthing systems, that should guarantee the absence of dangerous touch voltages. This is achieved through two effects: the division of the earth fault current between many earthing systems and the creation of a quasi equipotential surface. The second effect can be enhanced by the presence of buried metallic parts, such as light poles and water/gas pipelines, that can modify the earth surface potential profile. In order to characterize these buried conductors, an extensive measurement campaign was organized; in order to determine the resistance to earth of these buried conductors a simplified measurement protocol has been applied to more than 800 metallic objects. In this paper, the measurement set-up, the results and their analysis are reported.

Paired T-test analysis to measure the efficiency impact of a flying RPAS in the non-segregated airspace

Scipedia content — Mon, 01 Feb 2021 22:11:06 +0100

In the context of the ERAINT project, a number of human-in-the-loop simulations were conducted to study the implications of integrating a remote piloted aircraft system (RPAS) into the managed airspace. For the purpose of this study, the RPAS was assumed to be involved in surveillance missions, flying a large-endurance scan pattern. The area of surveillance was selected such that it crossed an active airway for approaches. Furthermore, the simulations also included situations in which the RPAS was involved in an emergency situation such as lost links and engine failures. From previous work, the results obtained from these simulations showed that the air traffic controllers (ATCs) could successfully manage the required separations for airspace safety assurance. Nevertheless, the number of total commands issued increased, in particular the number of requirements for altitude changes, and especially those destined to commercial aircraft. Given an aircraft's flying altitude impact on performance, one question rapidly arose: Is there an increase in flight costs for airlines as a result of the increased number of ATC commands issued to provide the necessary separation with the RPAS? For this purpose two metrics relating to time and fuel are defined such that they are targeted on quantifying the economic impact for commercial air traffic resulting from the presence of a RPAS. Both metrics are computed from the ADS-B traces of all aircraft in the sector and the results of each simulation are compared with those of a baseline simulation, in which the RPAS is not present. To improve on the comparison between each simulation's results we complement this study with a statistical analysis of the available data samples using paired t-test analyses to determine if the observed differences are statistically significant or simply due to random variability.

Peer Reviewed

Traffic Flow Model Based on Power Flow

Scipedia content — Mon, 01 Feb 2021 22:07:35 +0100

The article is research on the traffic rules of freeways. We analyze factors like traffic flow and safety performance respectively, and propose the theory basis for making more reasonable rules of the road. We first establish an evaluation system of traffic flow, which can be designed based on the average speed, the traffic density, the following ratio and the overtaking ratio. And we separately calculate the average speed and traffic density in heavy traffic and the opposite. Meanwhile, we obtain a relation of traffic flow and overtaking ratio or following ratio via fitting. We next construct an assessment system, based on IHSDM, and reach the conclusion that the more different the speed of vehicles is, the higher the relevant accident rate will be. As the accident rate reflects the safety performance directly, combining the conclusion with the overtaking model, we can probe into safety performance of freeways under different traffic rules. Afterwards, we compare the freeway network to power network to find a solution, and establish a traffic flow model based on power flow (TFPF). It calculates power flow. We utilize cellular automata (CA) method to simulate traffic circulation, and verify the accuracy of the above model with the obtained data. The verification shows the model is feasible in certain degree. Finally, the intelligent control of urban traffic flow applies to both light and heavy traffic. And it cannot only reduce the required time controlled by human factor, but also guide and schedule reasonably through the network monitoring, so as to ease traffic congestion and traffic accidents, and improve the efficiency of transportation.

Research on the Application of Internet of Things (IOT) for Urban Gas Industry

Scipedia content — Mon, 01 Feb 2021 22:07:18 +0100

he Internet of things is an important part of the next generation information technology. Also it is a vital development stage of the "informationization" era. The internet of things can connect the traditional urban gas industry to the network information platform. By changing the mode of production, the transformation and upgrading of traditional industries can be finally realized. This paper analyzes the wireless meter reading and remote service, wireless network monitoring and management of the network of gas pipelines on users' side. In this way, it aims to introduce the scheme of network of things now widely used in urban gas industry in China. In the scheme, applying scientific means based on Internet of things deals with effectively control over operation safety cared by all urban gas enterprises. In addition, in big data era, automatic collection of operation data and management data is also realized through Internet of things nowadays, not only laying solid foundation for delicacy management in enterprise, but also providing opportunities for integrating resources, creating new business and finding new profit growth points in traditional enterprises.

Synthetic Fuels from Electricity for the Swedish Transport Sector: Comparison of Well to Wheel Energy Efficiencies and Costs

Scipedia content — Mon, 01 Feb 2021 22:05:34 +0100

Synthetic fuels based on electricity, water, and carbon dioxide (CO2) may be necessary to cover the fuel demand in a sustainable transport sector based on renewable energy sources. The aim of this paper is to compare hydrogen, methane, methanol and diesel produced in this way. The main parameters for the analysis are well to wheel energy efficiency and costs, and the fuels are analysed in a Swedish context. The results indicate that methane and diesel could have the potential to be cost competitive in the near term, at least if common incentivesfor renewable transportation fuels are applied. Moreover, that hydrogen is the best option in terms of well to wheel energy efficiency, and that it in the longer term also may be cost competitive to the other fuels.

PRINCIPES CARTOGRAPHIQUES ET CARACTERISTIQUES UTILISATEURS DANS LA VISUALISATION DYNAMIQUE D’INFORMATION

Scipedia content — Mon, 01 Feb 2021 22:03:17 +0100

International audience; We detail an empirical animation study to assess how display design and user spatial ability and training might influence visuospatial decision-making with animated displays showing aircraft movements. We present empirical results of a visuospatial detection task with moving objects, based on response accuracy and response time, including a descriptive eye-movement analysis. We found significant differences in a visuospatial detection task of moving objects across animation design types and domain expertise levels based on viewers' visuospatial skill differences. With this empirical approach, we hope to better understand how users explore and extract information from animated displays. Based on these results, we aim to further develop empirically validated animation display design guidelines to increase their efficiency and effectiveness for decision-making with and about moving objects.; Nous présentons en détail une expérimentation évaluant des tâches utilisateurs dans un contexte de visualisation dynamique représentant des mouvements d'avions sur une interface de contrôle aérien. Nous cherchons à évaluer l'influence des principes d'affichage et du niveau d'expertise sur les aptitudes spatiales des participants à prendre des décisions. L'évaluation est basée sur l'exactitude des réponses données, le temps de réponse, et analyse descriptive des mouvements oculaires (eye tracking). Nous constatons des différences significatives dans la détection visuelle et spatiale d'objets en mouvement, selon le type d'animation et le niveau d'expertise des utilisateurs. À l'aide de cette expérimentation, nous espérons mieux comprendre comment les utilisateurs examinent, interprètent et extraient des connaissances à partir d'affichages dynamiques. À partir de ces résultats, nous souhaitons dégager des principes directeurs qui nous permettrons d'améliorer la conception d'animation, nous cherchons ainsi à accroître l'efficacité dans les prises de décisions des utilisateurs considérant la visualisation d'objets en mouvement.

Soft space regional planning as an approach for integrated transport and land use planning in Sweden – challenges and ways forward

Scipedia content — Mon, 01 Feb 2021 22:02:54 +0100

Current mobility patterns mean that many trips cross one or several municipal borders. This emphasises the need to integrate land-use and transport planning at regional functional scales. However, the Swedish planning system is characterised by a ‘municipal planning monopoly’, where local governments control the formal planning instruments. The lack of formal means for regional-level planning has sparked initiatives that can be characterised as soft spaces in planning. The paper analyses how soft space planning as spatial strategy making at regional level is influencing local-level planning. The analysis covers 10 municipalities in the Swedish Region of Skåne. The results illustrate that the dialogue-based process has established a broad consensus on the need to consider the regional scale in municipal planning. However, the results also show that the impact on planning is limited since the consensus-based process resulted in strategic objectives with limited influence on prevailing planning practices. Findings also illustrate that key concepts for operationalising the strategies – including densification and public transport accessibility – were defined and used differently in different municipalities. Consequently, a more stringent use, and stricter definitions, of core concepts could be a way to strengthen the capacity of soft space regional planning.

Volume Averaging of Multiphase Flows With Hydrate Formation in Subsea Pipelines

Scipedia content — Mon, 01 Feb 2021 21:56:32 +0100

In oil and gas pipeline operations, the gas, oil, and water phases simultaneously move through pipe systems. The mixture cools as it flows through subsea pipelines, and forms a hydrate formation region, where the hydrate crystals start to grow and may eventually block the pipeline. The potential of pipe blockage due to hydrate formation is one of the most significant flow-assurance problems in deep-water subsea operations. Due to the catastrophic safety and economic implications of hydrate blockage, it is important to accurately predict the simultaneous flow of gas, water, and hydrate particles in flowlines. Currently, there are few or no studies that account for the simultaneous effects of hydrate growth and heat transfer on flow characteristics within pipelines. This thesis presents new and more accurate predictive models of multiphase flows in undersea pipelines to describe the simultaneous flow of gas, water, and hydrate particles through a pipeline. A growth rate model for the hydrate phase is presented and then used in the development of a new three-phase model. The conservation equations of mass, momentum, and energy are formulated to describe the physical phenomena of momentum and heat transfer between the fluid and the wall. The governing equations are solved based on an analytical-numerical approach using a Newton-Raphson method for the nonlinear equations. An algorithm was developed in Matlab software to solve the equations from the inlet to the outlet of the pipeline. The developed models are validated against a single-phase model with mixture properties, and the results of comparative studies show close agreement. The new model predicts the volume fraction and velocity of each phase, as well as the mixture pressure and temperature profiles along the length of the pipeline. The results from the hydrate growth model reveal the growth rate and location where the initial hydrates start to form. Finally, to assess the impact of certain parameters on the flow characteristics, parametric studies have been conducted. The results show the effect of a variation in the pipe diameter, mass flow rate, inlet pressure, and inlet temperature on the flow characteristics and hydrate growth rates.

Augmented reality tower technology flight test

Scipedia content — Mon, 01 Feb 2021 21:55:05 +0100

ugmented reality technology adapted for air traffic control tower applications was used to track an OH-58C helicopter in proximity to an airport. A camera and 'see-through' display system was used to measure the registration error of static airport features and dynamic test aircraft. The observed registration errors of the test aircraft were largely attributable to two terms of error: 1) aircraft surveillance transport latency, and 2) registration error (from all sources) of the static environment. Compensating for registration errors of static objects and modeling aircraft movement reduces registration errors for dynamic (aircraft) objects to ≤2° of error for aircraft-surveillance transport latency ≤ 5 seconds, and to ≤1° of error for transport latency ≤ 2 seconds.

Measures to limit subsidence of underground oil pipeline in insular permafrost

Scipedia content — Mon, 01 Feb 2021 21:53:29 +0100

In this paper optimal solutions to limit the subsidence of underground oil pipeline in insular permafrost are proposed.

Relating airspace structure and capacity for extreme traffic densities

Scipedia content — Mon, 01 Feb 2021 21:46:02 +0100

Personal and unmanned aerial vehicles have received increasing media attention over the last decade. As a result of the growing excitement for these two aircraft types, many within and outside the aerospace industry envision a future in which large numbers of small aircraft fly over urban areas. With this vision for the future, the question arises what would be required, in terms of airspace organization, to make this feasible, or indeed, if it will be possible at all. In this context, the Metropolis project aims to investigate the influence of airspace structure on capacity, complexity, safety, and efficiency for high-density airspace. To this end, four airspace concepts, ranging from a decentralized direct routing concept, to a highly structured tube network using 4D trajectory-based operations, have been considered. The four concepts were compared by means of large-scale simulation experiments, for multiple scenarios that are extreme when compared to current air traffic densities. This paper presents an overview of the Metropolis project with a focus on the project objectives, design and implementation of airspace concepts, and preliminary simulation results.

Study of drought impact on inland navigation systems based on a flow network model

Scipedia content — Mon, 01 Feb 2021 21:37:25 +0100

International audience; Inland navigation systems are large scale networks that are used for transport. The navigation can be accommodated if the navigation condition are gathered, i.e. if there is enough volume of water in each part of the network. Thus, it is necessary to supply the inland navigation networks with water and to well dispatch the available volume of water on the whole system. This aim is generally achieved without difficulty in normal condition. However, during drought periods, the available volume of water is decreasing and the navigation conditions would not be reached every time. These situations are expected to be more current in the future specially in a global change context in which the frequency and the magnitude of drought events will increase. Hence, it is necessary to design some tools to study the resilience of inland navigation networks against drought events. For this purpose a flow network model, allowing to simulate the inland navigation systems, is proposed in this paper.

An aircraft performance model implementation for the estimation of global and regional commercial aviation fuel burn and emissions

Scipedia content — Mon, 01 Feb 2021 21:36:42 +0100

Estimates of global aviation fuel burn and emissions are currently nearly 10years out of date. Here, the development of the Aircraft Performance Model Implementation (APMI) software which is used to update global commercial aviation fuel burn and emissions estimates is described. The results from APMI are compared with published estimates obtained using the US Federal Aviation Administration’s System for Assessing Aviation’s Global Emissions (SAGE) for the year 2006. The number of global departures modelled with the APMI software is 8% lower compared with SAGE and reflects the difference between their commercial air traffic statistics data sources. The mission fuel burn, CO2 and H2O estimates from APMI are approximately 20% lower than those predicted by SAGE for 2006 while the estimate for the total global aircraft SOx emissions is approximately 40% lower. The estimates for the emissions of CO, HC and NOx are 10%, 140% and 30% higher than those predicted by SAGE respectively. The reasons for these differences are discussed in detail.

Real-time scheduling of electric vehicles for ancillary services

Scipedia content — Mon, 01 Feb 2021 21:24:09 +0100

© 2015 IEEE. This work is part of a project that aims to demonstrate the concept of Vehicle-to-Grid (V2G) with an operational fleet. A fleet of electric vehicles is operated with the objective of providing regulation services to the grid. The focus of this paper is on the real-time operation of the fleet. Specifically, given an optimal trajectory for the vehicle state of charge, schemes for distributing the regulation power commands among the vehicles are tested. A scheme based on a convex optimization problem is proposed. Several numerical illustrations and simulations show the effectiveness of the scheme respect to common scheduling heuristics in terms of accuracy.

Real-time estimation of critical vehicle accumulation for maximum network throughput

Scipedia content — Mon, 01 Feb 2021 21:21:36 +0100

Perimeter traffic flow control has recently been found to be a practical and efficient control scheme in mitigating traffic congestion in urban road networks. This control scheme aims at stabilising the accumulation of vehicles of the socalled network fundamental diagram near critical accumulation to achieve maximum network throughput. Nevertheless, the maximum throughput in urban road networks may be observed over a range of accumulation-values. In this work, an adaptive perimeter flow control strategy is proposed that allows the automatic monitoring of the critical accumulation to help maintain the accumulation near the optimal range of accumulation-values, while network's throughput is maximised. To this end, we design a Kalman filter-based estimation scheme that utilises real-time measurements of circulating flow and accumulation of vehicles to produce estimates of the currently prevailing critical accumulation. We use real data from an urban area with 70 sensors and show that the area exhibits a network fundamental diagram with low scatter. We demonstrate that the fundamental diagram is reproduced under different days but its shape and critical occupancy depend on the applied semi-real-time signal control and the distribution of congestion in the network. Results from the application of the estimation algorithm to the experimental data indicate good estimation accuracy and performance, and rapid tracking behaviour.

SEGMENTATION OF ACADEMIC COMMUNITY FOR THE PURPOSES OF MOBILITY PLAN DEVELOPMENT - CASE STUDY OF GDANSK UNIVERSITY OF TECHNOLOGY

Scipedia content — Mon, 01 Feb 2021 21:14:30 +0100

The objective of the paper is to analyse the structure of academic community for its transport behaviour and attitudes using the example of the Gdansk University of Technology (the GUT) in Poland. Once understood, the group can be divided into homogenous sub-groups and studied for their potential and ways to influence their behaviour, attitudes and transport patterns. The results may be used to develop dedicated actions designed to change the mentality and transport behaviour or to maintain sustainable transport patterns. The purpose of the research was to help draw up a GUT mobility plan using market segmentation, a method commonly used in management and marketing. The segmentation was based on transport behaviour surveys among the University’s employees. A total of 5 segments were distinguished: absolute car dependent (24%), conscious car drivers (27%), promising car drivers (7%), car free commuters (16%) and sustainable car owners (26%). In-depth analyses helped to aggregate the segments into 3 groups to be targeted with different measures aimed at changing mentality (24%), transport behaviour (34%) or maintaining sustainable transport habits (41%). Changing the proportion of particular segments and/or target groups can be one of the goals for the mobility plan. Based on the results of GUT research some dependences between affiliation to the segment and other describing variables were observed. However, further research is necessary into the other cases. If positively verified, the research can be a basis for the development of a universal method for dividing the academic community into segments based on the available data or simple criteria. This would reduce the time to prepare the mobility plan and ensure that the measures are targeted properly and developed with less effort.

Scheduling instruction effects for a statically pipelined processor

Scipedia content — Mon, 01 Feb 2021 21:12:26 +0100

Statically pipelined processors have a fully exposed datapath where all portions of the pipeline are directly controlled by effects within an instruction, which simplifies hardware and enables a new level of compiler optimizations. This paper describes an effect scheduling strategy to aggressively compact instructions, which has a critical impact on code size and performance. Unique scheduling challenges include more frequent name dependences and fewer renaming opportunities due to static pipeline (SP) registers being dedicated for specific operations. We also realized the SP in a hardware implementation language (VHDL) to evaluate the real energy benefits. Despite the compiler challenges, we achieve performance, code size, and energy improvements compared to a conventional MIPS processor.

Hazmat Routing: Safety and Security Challenges

Scipedia content — Mon, 01 Feb 2021 21:09:51 +0100

The railroad industry is being challenged by recent state regulations requiring the disclosure of routing information of trains carrying hazardous materials (hazmat) to the general public. While there is a need to know, the dissemination of such information is contrary to both industry practice and Federal Railroad Administration (FRA) rules. The conundrum is that there needs to be disclosure to first responders, law enforcement, fusion centers and the like to ensure the security and safety of the public."/jats:p" "jats:p"This paper addresses the rules regulating the movement and handling of hazmat, to include toxic inhalation hazard (TIH) material; government demands, particularly those at the state level to release the routes, commodities, and quantities to the general public; and the operational impacts and risks that could result. It then explores the security of how hazmat train routing information can be safeguarded while ensuring that first responders and affected communities have what is needed to address the risks and be able to effectively respond to incidents. The overlaps and conflicts found in the rules and regulations of the Transportation Security Administration (TSA) and the Pipeline and Hazardous Material Safety Administration (PHMSA) are also addressed.

Estimation of driver awareness of pedestrian based on Hidden Markov Model

Scipedia content — Mon, 01 Feb 2021 21:05:43 +0100

International audience; Understanding driver behaviors is an important need for the Advanced Driver Assistance Systems. In particular, the pedestrian detection systems become extremely distracting and annoying when they inform the driver with unnecessary warning messages. In this paper, we propose to study the driver behaviors whenever a pedestrian appears in front of the vehicle. A method based on the driving actions and the Hidden Markov Model (HMM) algorithm is developed to classify the driver awareness of pedestrian and the driver unawareness of pedestrian. The method is successfully validated using the collected data from the experiments that are conducted on a driving simulator. Furthermore, two simple methods based on the static parameters such as the Time-To-Collision and the Required Deceleration Parameter are also applied to our problem and are compared to the proposed method. The result shows a significant improvement of the HMM-based method compared to the simple ones.

Reliability analysis and performance predictions of aged pipelines subjected to internal corrosion: a Markov modelling technique

Scipedia content — Mon, 01 Feb 2021 21:04:19 +0100

To maintain the integrity of corroded oil and gas pipelines, the reliability at times of exposure over the lifecycle duration need to be understood. This paper describes the procedures for predicting the performance of internally corroded oil and gas pipelines using a probabilistic-based Markovian process. The Pipeline Corrosivity Index (PCI), which is expressed as a function of the retained pipe-wall thickness was used to describe the condition of the corroded pipelines at exposure durations for low, moderate, high and severe corrosion rates. The time variation of the predicted Pipeline Corrosivity Index (PCI) was compared with field measured Pipeline Corrosivity Indexes (PCIs) of corroded API X52 grade pipelines and the results indicate that the model developed in this research is viable for integrated management of aged corroded pipelines and remaining useful life predictions.Copyright © 2015 by ASME

Analysis and comparison of voltage dependent charging strategies for single-phase electric vehicles in an unbalanced Danish distribution grid

Scipedia content — Mon, 01 Feb 2021 20:57:38 +0100

This paper studies four voltage dependent solutions for modulating the charging of multiple Electric Vehicles (EVs) in a real Danish network. Uncontrolled EV charging, especially in grid with high EV penetration, can result in overloaded lines and transformers, low-voltages and other performance degradations which lead to poor quality of supply. Therefore, a decentralized control for modulating the EVs’ charging current is developed, which sets the EV reference current based on the phase-to-neutral voltage at the EV connection node. Due to the controller’s decentralised feature, EVs plugged-in on phases with lower voltages are constrained during the charging period. In order to solve instability issues which may occur due to lack of communication between the controllers, several improvements are applied to the aforementioned droop control. Simulation results demonstrate the performance of the voltage dependent"br/"controls for a real Danish distribution grid."br

Analyzing stakeholders’ commitment in urban logistics projects by using Community of Practice theory

Scipedia content — Mon, 01 Feb 2021 20:55:21 +0100

International audience

Pilot Perception and Use of ADS-B In Traffic and Weather Services (TIS-B and FIS-B)

Scipedia content — Mon, 01 Feb 2021 20:50:16 +0100

This project was funded by the U.S. Department of Transportation - Federal Aviation Administration through the Consortium in Aviation Operations Research (NEXTOR II) Center of Excellence.

The Economics of Patent Backlog

Scipedia content — Mon, 01 Feb 2021 20:45:21 +0100

Patent offices around the world face massive backlogs of applications, which threatens to slow down the pace of technological progress. However, economists lack analytical tools to address the issue. This paper provides a model of patent backlog inspired from the traffic congestion literature. Inventors in the cohort are heterogeneous with respect to desired patent pendency duration and react in anticipation of the waiting time resulting from the backlog. They can accelerate or slow down pendency duration by adapting their filing strategy. We find that the backlog impedes patent examination progress by providing incentives to strategically manipulate pendency. We discuss four policy responses: increasing examination capacity; introducing a penalty fee; altering the value of pending applications; and allowing deferred examination.

Technology Research on Traffic Organization of Wuhan Municipal Engineering Projects Under Construction

Scipedia content — Mon, 01 Feb 2021 20:43:47 +0100

Present Chinese big cities are facing one common problem that road resources have being occupied by the construction of traffic projects. In order to solve the problems of traffic organization during construction properly, this paper put forward the research content and technical principle of municipal engineering projects traffic organization firstly, then suggest a method of traffic organization for viaduct according to the characteristics of the construction period that is divided into three stages (pipelines reconstruction renovation, substructure construction and superstructure construction), which was applied to Traffic organization scheme for construction period of Wuhan Road in Hankou, and it has achieved desired effect. Refer to traffic organization of Wuhan municipal projects under construction, other types of construction projects can be elevated to organize traffic reasonably and keep city traffic common operation, with the consideration of the project characteristics and the actual situation of traffic during construction. Keywords-municipal engineering projects ; under construction ; traffic organization ; traffic impact analysis ; Wuhan city.

Context-Aware Online Spatiotemporal Traffic Prediction

Scipedia content — Mon, 01 Feb 2021 20:42:26 +0100

With the availability of traffic sensors data, various techniques have been proposed to make congestion prediction by utilizing those datasets. One key challenge in predicting traffic congestion is how much to rely on the historical data v.s. The real-time data. To better utilize both the historical and real-time data, in this paper we propose a novel online framework that could learn the current situation from the real-time data and predict the future using the most effective predictor in this situation from a set of predictors that are trained using historical data. In particular, the proposed framework uses a set of base predictors (e.g. A Support Vector Machine or a Bayes classifier) and learns in real-time the most effective one to use in different contexts (e.g. Time, location, weather condition). As real-time traffic data arrives, the context space is adaptively partitioned in order to efficiently estimate the effectiveness of each predictor in different contexts. We obtain and prove both short-term and long-term performance guarantees (bounds) for our online algorithm. Our experiments with real-world data in real-life conditions show that the proposed approach significantly outperforms existing solutions.

Risk Assessment on Debris Flow Hazard along Linear Construction Civil Engineering Based on Satellite Remote Sensing and Fuzzy Comprehensive Evaluation Method

Scipedia content — Mon, 01 Feb 2021 20:27:56 +0100

Taking the Lixian-Guangyuan segment of Lanzhou-Chengdu-Chongqing product oil pipeline as an example, the satellite images in the study area were produced based on multi-source remote sensing information. The authors then established the remote sensing interpretation signs for debris flows according to the data of geological and ecological environment. After that, the 3D remote sensing image models of debris flows were constructed by texture mapping technique and DEM (Digital Elevation Model). Based on the satellite images and the 3D models, debris flows along the pipelines were identified, and their features were extracted for risk assessment, which were designed into the different evaluation indexes. The authors thus introduced fuzzy comprehensive evaluation model to assess the debris flows based on these evaluation indexes. According to field investigation, the identified and evaluated results were checked to be well. It is obvious that this assessment method can quickly identify debris flows along linear construction civil engineering and evaluate their risk, which would provides scientific basis for engineering disaster prevention. Keywords-Oil pipeline;Remote sensing detection;3D model;Debris flow hazard;Fuzzy comprehensive evaluation model

Communication, Navigation and Surveillance Performance Criteria for Safety-Critical Avionic Systems

Scipedia content — Mon, 01 Feb 2021 20:25:33 +0100

The demand for improved safety, integrity and efficiency due to the rapid expansion of global air transport and the growing concern for environmental sustainability issues poses significant challenges on the development of future Communication, Navigation and Surveillance/Air Traffic Management (CNS/ATM) and Avionics (CNS+A) systems. High-integrity, highreliability and all-weather services are required in the context of four dimensional Trajectory Based Operations / Intent Based Operations (TBO/IBO). The Next Generation Flight Management Systems (NG-FMS), which are the primary automated navigation and guidance services in manned aircraft and Remotely-Piloted Aircraft System (RPAS) will have to address these challenges. After describing the key system architectures, the mathematical models for trajectory generation and CNS performance criteria evaluation are presented. An evaluation of the proposed concepts and methodologies is accomplished by simulation. The results demonstrate the functional capability of the avionics and ATM systems to generate cost-effective trajectory profiles satisfying both operational and environmental requirements, as well as satisfying the CNS performance criteria.

CHANGING ATTITUDES TOWARDS CAR SHARING: A BIG CHANCE FOR URBAN ECOLOGY?

Scipedia content — Mon, 01 Feb 2021 20:24:21 +0100

Concept of an advanced hyperspectral remote sensing system for pipeline monitoring

Scipedia content — Mon, 01 Feb 2021 20:23:28 +0100

occupied by oil pipelines and storage facilities are prone to severe contamination due to leaks caused by natural forces, poor maintenance or third parties. These threats have to be detected as quickly as possible in order to prevent serious environmental damage. Periodical and emergency monitoring activities need to be carried out for successful disaster management and pollution minimization. Airborne remote sensing stands out as an appropriate choice to operate either in an emergency or periodically. Hydrocarbon Index (HI) and Hydrocarbon Detection Index (HDI) utilize the unique absorption features of hydrocarbon based materials at SWIR spectral region. These band ratio based methods require no a priori knowledge of the reference spectrum and can be calculated in real time. This work introduces a flexible airborne pipeline monitoring system based on the online quasi-operational hyperspectral remote sensing system developed at Fraunhofer IOSB, utilizing HI and HDI for oil leak detection on the data acquired by an SWIR imaging sensor. Robustness of HI and HDI compared to state of the art detection algorithms is evaluated in an experimental setup using a synthetic dataset, which was prepared in a systematic way to simulate linear mixtures of selected background and oil spectra consisting of gradually decreasing percentages of oil content. Real airborne measurements in Ettlingen, Germany are used to gather background data while the crude oil spectrum was measured with a field spectrometer. The results indicate that the system can be utilized for online and offline monitoring activities.

Empirical Study on the impact of Urbanization on air Transport Industry in Shanghai

Scipedia content — Mon, 01 Feb 2021 20:20:00 +0100

Urbanization is a process of overall development on the aspects of population, economy, society and land. As the carrier of economic, social communication and logistics interaction between the city and outside world, air transport industry is greatly affected by urbanization. By choosing 1995-2012's statistical data of population, economy, society and land to evaluate the overall level of urbanization and 1995-2012's statistical data of air cargo traffic and air passenger traffic to indicate the development of air transport industry, this paper establishes a comprehensive evaluation system of urbanization based on the method of entropy, and use correlation index and regression analysis model to analyzes the relation between urbanization and air transport industry development in Shanghai. The results show that urbanization has a strong correlation with air transport industry in Shanghai, and the urbanization of population, economy and land gradually become the main force to drive the development of air transport industry, among which the urbanization of economy is the most important force.

Liénard type model of fluid flow in pipelines: Application to estimation

Scipedia content — Mon, 01 Feb 2021 20:08:31 +0100

International audience; This paper highlights how fluid flow in a pipelinecan be represented as a nonlinear model of so-called Liénardtype. It is then shown how the structure of this model is suitablefor the design of algorithms to identify parameters of a pipelineor estimate unmeasurable states. This approach is illustratedby simulation results, for instance showing how to estimate theDarcy-Weisbach friction coefficient or the fluid acceleration.

Equilibrium Analysis in the Parking Search Game with Heuristic Strategies

Scipedia content — Mon, 01 Feb 2021 20:02:33 +0100

The tremendous growth of urbanization calls for several interventions for the efficient and environmentally sustainable management of various urban processes, including the road traffic management. Indeed, transportation engineers need to be able to understand how drivers decide their route to effectively address the plethora of challenges for alleviating the congestion phenomena in city areas. In this paper, we model drivers' decision-making with respect to the parking space search, which has been regarded as one of the major causes of traffic congestion. We view the parking search as an instance of sequential search problems and present a game-theoretic investigation of the efficiency of heuristic parking search strategies to locate available parking spot at minimum walking and driving overhead. The analytical study concludes by drawing similarities between the parking game and well-known archetypal games that the Game Theory examines.

Comparative study of regulations, codes and standards and practices on hydrogen fuelling stations

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

This work deals with a comparative study of regulations, codes and standards for hydrogen fuelling station dedicated for light duty land vehicles in the following countries: United States (California), United Kingdom, Italy, Germany, Canada, Sweden, Norway, Denmark and Spain. The following technical components of a hydrogen fuelling station are included in the scope of the study: the hydrogen storage systems (cryogenic or compressed gases) and buffer storage, the compressor stations, the high pressure buffer storage, the cooling systems for hydrogen, the dispensing equipments and the dispensing area. The hydride storage, the pipelines, on site production and the hydrogen vehicle have been excluded. The analysis, performed in September 2014 in a report from INERIS DRA-14-141532-06227C BENCHMARK STATIONS-SERVICE HYDROGENE, is based on documents collected by bibliographic review and information obtained through a questionnaire sent to authorities and IA HySafe [1] members in the above mentioned countries. This paper gives a synthesis of the regulations and on permitting process in the different studied countries (including the new European Directive on the deployment of alternative fuels infrastructure in Europe [2]), it develops the required safety barriers in the different parts of a fuelling station and specially for the dispensing area, gives an overview of the different approaches for safety distances and processes to obtain licences to operate.

Estimation of train dwell time at short stops based on track occupation event data

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

Train dwell time is one of the most unpredictable components of railway operations, mainly because of the varying volumes of alighting and boarding passengers. However, for reliable estimations of train running times and route conflicts on main lines, it is necessary to obtain accurate estimations of dwell times at the intermediate stops on the main line, the so-called short stops. This is a great challenge for a more reliable, efficient and robust train operation. Previous research has shown that the dwell time is highly dependent on the number of boarding and alighting passengers. However, these numbers are usually not available in real time. This paper discusses the possibility of a dwell time estimation model at short stops without passenger demand information by means of a statistical analysis of track occupation data from the Netherlands. The analysis showed that the dwell times are best estimated for peak and off-peak hours separately. The peak-hour dwell times are estimated using a linear regression model of train length, dwell times at previous stops and dwell times of the preceding trains. The off-peak-hour dwell times are estimated using a non-parametric regression model, in particular, the k-nearest neighbor model. There are two major advantages of the proposed estimation models. First, the models do not need passenger flow data, which is usually impossible to obtain in real time in practice. Second, detailed parameters of rolling stock configuration and platform layout are not required, which makes the model more generic and eases implementation. A case study at Dutch railway stations shows that the estimation accuracy is 85.8%-88.5% during peak hours and 80.1% during off-peak hours, which is relatively high. We conclude that the estimation of dwell times at short stop stations without passenger data is possible.

Estimating Urban Traffic Patterns through Probabilistic Interconnectivity of Road Network Junctions

Scipedia content — Mon, 01 Feb 2021 19:59:46 +0100

The emergence of large, fine-grained mobility datasets offers significant opportunities for the development and application of new methodologies for transportation analysis. In this paper, the link between routing behaviour and traffic patterns in urban areas is examined, introducing a method to derive estimates of traffic patterns from a large collection of fine-grained routing data. Using this dataset, the interconnectivity between road network junctions is extracted in the form of a Markov chain. This representation encodes the probability of the successive usage of adjacent road junctions, encoding routes as flows between decision points rather than flows along road segments. This network of functional interactions is then integrated within a modified Markov chain Monte Carlo (MCMC) framework, adapted for the estimation of urban traffic patterns. As part of this approach, the data-derived links between major junctions influence the movement of directed random walks executed across the network to model origin-destination journeys. The simulation process yields estimates of traffic distribution across the road network. The paper presents an implementation of the modified MCMC approach for London, United Kingdom, building an MCMC model based on a dataset of nearly 700000 minicab routes. Validation of the approach clarifies how each element of the MCMC framework contributes to junction prediction performance, and finds promising results in relation to the estimation of junction choice and minicab traffic distribution. The paper concludes by summarising the potential for the development and extension of this approach to the wider urban modelling domain.

Document type: Article

Efficient Dynamic Compressor Optimization in Natural Gas Transmission Systems

Scipedia content — Mon, 01 Feb 2021 19:59:24 +0100

The growing reliance of electric power systems on gas-fired generation to balance intermittent sources of renewable energy has increased the variation and volume of flows through natural gas transmission pipelines. Adapting pipeline operations to maintain efficiency and security under these new conditions requires optimization methods that account for transients and that can quickly compute solutions in reaction to generator re-dispatch. This paper presents an efficient scheme to minimize compression costs under dynamic conditions where deliveries to customers are described by time-dependent mass flow. The optimization scheme relies on a compact representation of gas flow physics, a trapezoidal discretization in time and space, and a two-stage approach to minimize energy costs and maximize smoothness. The resulting large-scale nonlinear programs are solved using a modern interior-point method. The proposed optimization scheme is validated against an integration of dynamic equations with adaptive time-stepping, as well as a recently proposed state-of-the-art optimal control method. The comparison shows that the solutions are feasible for the continuous problem and also practical from an operational standpoint. The results also indicate that our scheme provides at least an order of magnitude reduction in computation time relative to the state-of-the-art and scales to large gas transmission networks with more than 6000 kilometers of total pipeline.

Progress in application on the prediction of rolling bearing performances for urban rail and traffic engineering

Scipedia content — Mon, 01 Feb 2021 19:56:12 +0100

present, an unprecedented development situation of the urban rail and traffic engineering is presented. Bearing as a key component of vehicle operation safety, its performances and reliability should achieve higher requirements. Because the number of characteristi c data of bearing performances is small and prior information on probability distributions and trends is poor, statistics has difficulty in assessing the bearing performance. In order to study the nonlinear dynamic characteristics of rolling bearing performances, a unified representation of variable uncertainty and function polytrope characteristics of rolling bearing performances are proposed in information-poor relation space, which reveals its evolvement rule of nonlinear dynamic characteristics. The development of bearing technology for the urban rail and traffic Engineering should comply with safe operation, high speed, a longer maintenance period and the excellent running comfort.

Medium scale CO2 releases

Scipedia content — Mon, 01 Feb 2021 19:51:47 +0100

International audience; The scale of proposed carbon dioxide (CO2) capture and storage (CCS) chains also draws attention to the hazards posed by the transport mode, enabling the link from source to sink. As such, the adverse consequences of an accidental release from transport pipelines or other equipment containing CO2 at high pressure in a dense-phase (supercritical or liquid) state are (re)considered in theory and in practice. Several experimental observations of large-scale CO2 releases have been made, and yet the physics and thermodynamics involved are not fully understood. The work presented here provides a database focused on the specificities of the release and the dispersion of the carbon dioxide cloud in case of substantial variations of storage (temperature and pressure) and discharge conditions (nozzle size).

Document type: Conference object

Where is my next friend? Recommending enjoyable profiles in location based services

Scipedia content — Mon, 01 Feb 2021 19:51:28 +0100

How many of your friends, with whom you enjoy spending some time, live close by? How many people are at your reach, with whom you could have a nice conversation? We introduce a measure of enjoyability that may be the basis for a new class of location-based services aimed at maximizing the likelihood that two persons, or a group of people, would enjoy spending time together. Our enjoyability takes into account both topic similarity between two users and the users’ tendency to connect to people with similar or dissimilar interest. We computed the enjoyability on two datasets of geo-located tweets, and we reasoned on the applicability of the obtained results for producing friend recommendations. We aim at suggesting couples of users which are not friends yet, but which are frequently co-located and maximize our enjoyability measure. By taking into account the spatial dimension, we show how 50 % of users may find at least one enjoyable person within 10 km of their two most visited locations. Our results are encouraging, and open the way for a new class of recommender systems based on enjoyability.

Toward V2I communication technology-based solution for reducing road traffic congestion in smart cities

Scipedia content — Mon, 01 Feb 2021 19:51:05 +0100

Due to the limited capacity of road networks and sporadic on-route events, road traffic congestions are posing serious problems in most big cities worldwide and resulting in considerable number of casualties and financial losses. In order to deal efficiently with these problems and alleviate their impact on individuals, environment, and economic activities, advanced traffic monitoring and control tools (e.g., SCATS and SCOOT) are being widely used in hundreds of major cities in the world. However, due to increasing road traffic and dynamic spatio-temporal events, additional proactive mechanisms remain needed to prevent traffic congestions. Within this context, we argue that the emergent V2X communication technologies, and especially V2I (Vehicle to Infrastructure), would be of great help. To this end, we investigate in this paper the opportunities that could be offered by V2I technology in improving commuters' journey duration and mitigating the above irritating and frequent problems. We then propose an approach where road-side facilities (e.g. traffic light controllers at road intersections) communicate traffic light cycle information to approaching vehicles. Based on this information, the vehicles collaboratively determine their optimal speeds and other appropriate actions to undertake in order to cross road intersections with minimum delays while ultimately avoiding stoppings. The obtained evaluation results show that our approach achieves a significant gain in terms of the commuters' average travel time reduction.