Scipedia: Documents published in 2012

Formation and Propagation of Local Traffic Jam

Scipedia content — Tue, 23 Mar 2021 05:58:52 +0100

Large scale traffic congestion often stems from local traffic jam in single road or intersection. In this paper, macroscopic method was used to explore the formation and propagation of local traffic jam. It is found that (1) the propagation of traffic jam can be seen as the propagation of traffic signal parameters, that is, virtual split and virtual green time; (2) for a road with endogenous flow, entrance location influences the jam propagation. With the same demand (upstream links flow and entrance flow), the upstream got more influence; (3) when a one-lane road is thoroughly congested, virtual signal parameters everywhere are the same as that at stop line; for a basic road, the virtual signals work in a cooperative manner; (4) phase sequence is one important parameter that influences traffic performances during peak hour where spill back of channelization takes place. The same phase plan for left-turn flow and through flow would be preferred; (5) signal coordination plays an important role in traffic jam propagation and hence effective network signal parameters should be designed to prevent jam from propagation to the whole network. These findings would serve as a basis for future network traffic congestion control.

Document type: Article

Research on Alignment Consistency of Highways with the Basis of 85MSR

Scipedia content — Tue, 23 Mar 2021 05:09:59 +0100

The alignment consistency of highways is an important guarantee for vehicle safety. In this thesis, by comparing the computing methods of ΔV85 and 85MSR, the author concludes that 85MSR is a more appropriate way to evaluate the highway alignment consistency. The author studies Ningfu section on Heda superhighway with 85MSR, pointing out the section with poor alignment consistency, and provides basic data for the analysis and prevention of this section and road improvement.

Document type: Article

A New Algorithm Design for the Real-time Electrochemical Impedance Monitoring System

Scipedia content — Mon, 22 Mar 2021 23:18:08 +0100

BSTRACT: It is generally known that electrochemical impedance spectroscopy is a powerful technique and itsreal-time application has been demanded for prompt observations on instantaneous electrochemicalchanges. Nevertheless, long measurement time and laborious analysis procedures have hindereddevelopment of it. Solving the problems, here I report of a new algorithm design for developmentof a real-time electrochemical impedance monitoring system, which potentially provides a guidelinein developing monitoring systems of electric vehicles batteries and other electrochemical powerplants. The significant progress in this report is employment of the parallel processing protocolwhich connects independent sub functions to successfully operate with avoiding mutual interrup-tions. Therefore, all the processes required to monitor electrochemical impedance changes in real-time are properly operated. To realize the conceptual scheme, a Labview program was coded withsub functions units which conduct their processes individually and only data are transferredbetween them through the parallel pipelines. Finally, measured impedance spectra and analysisresults are displayed, which are synchronized according to the time of change.Keywords: Impedance spectroscopy, Electrochemical instrument, Real-time measuremen

Document type: Article

An Efficient Drift-Flux Closure Relationship to Estimate Liquid Holdups of Gas-Liquid Two-Phase Flow in Pipes

Scipedia content — Mon, 22 Mar 2021 20:16:22 +0100

The reliable predictions of liquid holdup and pressure drop are essential for pipeline design in oil and gas industry. In this study, the drift-flux approach is utilized to calculate liquid holdups. This approach has been widely used in formulation of the basic equations for multiphase flow in pipelines. Most of the drift-flux models have been developed on an empirical basis from the experimental data. Even though, previous studies showed that these models can be applied to different flow pattern and pipe inclination, when the distribution parameter is flow pattern dependent. They are limited to a set of fluid properties, pipe geometries and operational conditions. The objective of this study is to develop a new drift-flux closure relationship for prediction of liquid holdups in pipes that can be easily applied to a wide range of flow conditions. The developed correlation is compared with nine available correlations from literatures, and validated using the TUFFP (Fluid Flow Projects of University of Tulsa) experimental datasets and OLGA (OiL and GAs simulator supplied by SPTgroup) steady-state synthetic data generated by OLGA Multiphase Toolkit. The developed correlation performs better in predicting liquid holdups than the available correlations for a wide range of flow conditions.

Document type: Article

Energy, Pollutant Emissions and Other Negative Externality Savings from Curbing Individual Motorized Transportation (IMT): A Low Cost, Low Technology Scenario Analysis in Brazilian Urban Areas

Scipedia content — Mon, 22 Mar 2021 20:00:35 +0100

This article examines the inefficient use of resources in the Brazilian transportation system. The energy use growth and external cost generation in this essential economic sector are considerable, and the trend is towards an increasing problem in the coming years. The continued expansion of Brazilian cities and the increase in demand for mobility is a result of a substantial growth in the number of road transport users, as increased earnings enable lower income groups to acquire and use individual motorized means of transport. The aim of this paper is to estimate the potential gains from reducing individual motorized transport by the year 2020. This investigation concludes that in a conservationist scenario, by prioritizing low cost, low technology public policies—which include operation of Bus Rapid Transit systems, walking and cycling facilities and congestion charges, among others—it should be possible to save over USD 30 billion and USD 26 billion in external transportation and infrastructure costs, respectively, up to 2020. In addition, these public policies can save more than 35 million Tons of Oil Equivalents in energy consumption and avoid almost 4,000 thousand tons of local pollution emissions and 37,500 thousand tons of GHG emissions in the same period.

Document type: Article

Passive safety evaluation in driving adapted vehicles

Scipedia content — Tue, 16 Feb 2021 13:21:02 +0100

[EN] Driving a private vehicle represents nowadays one of the most viable ways by which disabled drivers can maintain their mobility and transport conditions. To do so it is necessary to adapt a vehicle to the user's residual capabilities. Nevertheless the technical aids installed in the vehicles must fulfill the same safety requirements as standard vehicles. This paper shows the results of a research project held at the Automobile Laboratory of the Technical University of Valencia (Spain), the main objective being to generate basic design criteria for improving the passive safety behaviour of the adapted vehicle under different impact conditions. The research project whose partial results are shown in this paper was developed by the Automobile Laboratory of the Technical University of Valencia (Spain), under the auspices of the Spanish Ministry of Science and Innovation (Ref. TRA2005-08649) during the years 2006–2008. Dols Ruiz, JF.; Masiá Vañó, J.; Eixerés Tomás, B. (2012). Passive Safety evaluation in driving adapted vehicles. International Journal of Vehicle Safety. 6(1):77-89. doi:10.1504/IJVS.2012.048534 S 77 89 6 1

Emission factors for heavy metals from diesel and petrol used in European vehicles

Scipedia content — Tue, 16 Feb 2021 13:14:16 +0100

Heavy metals constitute an important group of persistent toxic pollutants occurring in ambient air and other media. One of the suspected sources of these metals in the atmosphere is combustion of transport fuels in road vehicles. However estimates of the emissions of these metals from road vehicles as reported in national emission inventories show a very high variability in emission factors used. This paper provides high quality data on concentrations of heavy metals in fuels and derives default emission factors from these. The paper discusses these values against the emission estimates presently reported by the Parties to the LRTAP Convention. The measured concentrations of heavy metals in petrol and diesel fuel show a high variability between different samples taken at gas stations throughout Europe. Metal concentrations in road transport fuels vary over two orders of magnitude, but all remain in the ppb region (a few tenths of a ppb to a few hundred ppb for all metals). The frequency distributions of the measurements could be approximated by lognormal distributions. We could not detect a significant difference between samples from different countries. The fuel based emission factors as derived in this study are compared with those related to lubricant use as published by Winther and Slentø (2010). For most HMs studied here, this would lead to an two to fourfold increase of the tailpipe emissions as derived from the fuel concentrations. The emission factors, including 95 percent confidence intervals were derived from a statistical analysis of the survey data. The proposed emission factors were generally lower than previously published emission factors. National emissions of heavy metals from vehicle exhaust, estimated in this study therefore are in many cases considerably lower than those reported by the countries for this source.

An integrated approach for risk assessment of CO2 infrastructure in the COCATE project

Scipedia content — Tue, 16 Feb 2021 13:13:48 +0100

n innovative risk analysis model has been developed in order to quantify and analyse safety risks related to loss-of- containment scenarios in the pipeline transport of CO2. The risk model integrates the identified failure modes, consequence estimates and emergency response, producing consistent risk profiles based on complete outcome spaces and for different system design choices. The method involves integration in a Bayesian Belief Network (BN) of analytical equations for gas dispersion combined with statistics and expert estimates of particularly uncertain variables. Future failure initiators, scenarios and impacts are captured in a graphical structure which represents and calculates the effects of common causes. The test case for the integrated risk model will be a large CO2 capture and transport network at the Le Havre industrial zone with export to Rotterdam. The primary relative advantages of the BN risk model approach are discussed.

Developing a long-term global tourism transport model using a behavioural approach: implications for sustainable tourism policy making.

Scipedia content — Tue, 16 Feb 2021 13:13:34 +0100

This paper explores the creation and use of a long-term global tourism transport model for private and public sector tourism policy makers. Given that technology is unlikely to reduce tourism transport's impact on climate change sufficiently to avoid serious dangers, behavioural change is necessary. The model presented here helps policy makers and the tourism sector evaluate behavioural change measures. Such tools to assess long-term (up to a century) policy impacts do not currently exist. Projecting behavioural change over such long periods is difficult with contemporary economic modelling. This paper's model is founded in psychological economics theory and mechanisms at work in product diffusion. It describes the tourism system based on identifiable mechanisms and not on statistical relations with only current validity. It delivers global numbers of trips and distances travelled per transport mode as a function of transport cost, travel time, population and income distribution. The model is based on theories including product innovation theory (Bass model) and prospect theory (psychological value). It has been successfully calibrated to tourism development between 1900 and 2005 and tested against future low and high growth economic and demographic scenario combinations. Implications for tourism travel and climate change are discussed.

Experimental assessment of low-cost GPS-based localization in railway worksite-like scenarios

Scipedia content — Tue, 16 Feb 2021 13:12:15 +0100

Since GPS has been made available for civil usage, satellite-based localization in open space has become a more and more common option for vehicular tracking and for a number of commercial applications. The accuracy of the localization results and the availability of the localization system are influenced by several factors, such as the characteristics of the devices used, the surrounding environment, and the distance from reference stations. The possibility of exploiting off-the-shelf GPS devices, in the contest of a composite multi-sensor localization, is currently being investigated within the framework of the ALARP project [9] , where it is required to accurately localize workers in railway worksites. This paper presents the results of an experimental campaign aimed at determining if, and under which conditions, low-cost GPS devices can be used in such a scenario. The evaluation is performed comparing data from low-cost GPS devices to data collected using a highly accurate reference system. The analysis permits to assess the feasibility of two different, very popular, commercial GPS devices for the ALARP requirements on localization.

Interactions of environmental and safety measures for sustainable road transportation

Scipedia content — Tue, 16 Feb 2021 13:05:06 +0100

Purpose: This study examined interactions of environmental and safety measures for road transportation. Method: Road-safety effects of various measures targeting environmental problems of road transportation and environmental effects of various road-safety measures were reviewed. Results:"br/"The results showed that a vast majority of the examined measures support both policy objectives and thereby contribute effectively to sustainable transportation. However, there were also measures with conflicting effects, although the number of those measures was limited. In addition, there were a number of measures with no interaction. Furthermore, many potential effects were not documented and therefore in many instances only likely effects were noted. Conclusion: There are two practical implications of this study. First, those measures that result in double benefits should be encouraged to be implemented. Second, in case of conflicting measures, the specific implementations should attempt to minimize the negative effects.

Air Transport Network: a short review

Scipedia content — Tue, 16 Feb 2021 13:03:39 +0100

transport is a key infrastructure of modern societies. In this paper we review some recent approaches to air transport, which make extensive use of theory of complex networks. We discuss possible networks that can be defined for the air transport and we focus our attention to networks of airports connected by flights. We review several papers investigating the topology of these networks and their dynamics for time scales ranging from years to intraday intervals, and consider also the resilience properties of air networks to extreme events. Finally we discuss the results of some recent papers investigating the dynamics on air transport network, with emphasis on passengers traveling in the network and epidemic spreading mediated by air transport.

Comment: 28 pages, 6 figure

New international services and the competitiveness of Tokyo International Airport

Scipedia content — Tue, 16 Feb 2021 12:57:20 +0100

With the completion of Narita International Airport (Narita) in the Greater Tokyo Area, Tokyo International Airport (Haneda) was practically downgraded to a domestic airport. It lost its position as a key traffic hub for domestic to international air transport in Japan. Now the Japanese government is trying to expand its international role again by the resumption of international air services at the airport. A route choice probability model is applied to show how Haneda’s hub competitive position in its connecting markets from Japan has changed since the resumption of these services. The results reveal that Haneda’s market shares increased significantly in the markets between Japan and Asia-Oceania, between Japan and Europe and between Japan and North America. The dense domestic networks offered at Haneda appear to connect well with the newly started international flights to Asia-Oceania, Europe and North America. The competitive position of Haneda in the connecting markets from Japan is expected to increase towards 2013 when its international air networks will be expanded further.

Methods for value assessment of water and sewer pipelines

Scipedia content — Tue, 16 Feb 2021 12:53:16 +0100

The value of existing assets has become a factor of special interest to the asset owners as outsourcing of maintenance duties has increased. The value of water and sewer systems should be assessed in order to follow up the development of the network's long-term condition during a maintenance partnership contract and to determine the optimal renovation timing and method. Many factors affect the condition of the network, which makes the determination of the service life difficult. The use of existing value assessment methods is also essential in order to assess the systems economically. However, the value should be addressed holistically instead of determining only the economic value of the system. In this paper, we provide a comprehensive discussion on the value assessment of the water and sewer systems. A method for assessing the development of value during maintenance or renovation contract is presented.

Studying Shared Situation Awareness by Agent-Based Simulation

Scipedia content — Tue, 16 Feb 2021 12:52:58 +0100

Shared Situation Awareness is an often employed concept in domains where teams of agents have to solve complex tasks in a distributed manner, like incident management and air traffic control. Although widely studied in the literature, the concept is difficult to be analyzed in a systematic manner, due to 1) the abundance of factors that can be related to Shared SA, and 2) the lack of a commonly agreed, formal definition. This paper proposes Agent-Based Social Simulation as a scientific method to study questions related to Shared SA. Founded in theories from Social Science, an agent-based framework is presented, which allows users to explore a variety of hypothetical scenarios in an automated manner. The resulting global patterns are illustrated by discussing a number of simulation results for different parameter settings. These simulations show that, although preliminary, the presented framework has potential as an analytical tool for researchers and policy makers.

Competition in multi-modal transport networks: A dynamic approach

Scipedia content — Tue, 16 Feb 2021 12:47:48 +0100

This discussion paper resulted in a publication in 'Transportation Research Part B: Methodological' , 2013, 53, 31-44. We analyse the behaviour of market participants in a multi-modal commuter network where roads are not priced, but public transport has a usage fee, which is set while taking the effects on the roads into account. In particular, we analyse the difference between markets with a monopolistic public transport operator, which operates all public transport links, and markets in which separate operators own each public transport link. To do so, we consider a simple transport network consisting of two serial segments and two parallel congestible modes of transport. We obtain a reduced form of the public transport operator's optimal fare setting problem and show that, even if the total travel demand is inelastic, serial Bertrand-Nash competition on the public transport links leads to different fares than a serial monopoly; a result not observed in a static model. This results from the fact that trip timing decisions, and therefore the generalized prices of all commuters, are influenced by all fares in the network. We then use numerical simulations to show that, contrary to the results obtained in classic studies on vertical competition, monopolistic fares are not always higher than duopolistic fares; the opposite can also occur. We also explore how different parameters influence the price differential, and how this affects welfare.

Traffic flow harmonization in expressway merging

Scipedia content — Tue, 16 Feb 2021 12:40:00 +0100

Steering a vehicle is a task increasingly challenging the driver in terms of mental resources. Reasons for this include the increasing volume of road traffic and a rising quantity of road signs, traffic lights, and other distractions at the roadside (such as billboards), to name a few. The application of Advanced Driver Assistance Systems, in particular if taking advantage of Ambient Intelligence (AmI) technology, can help to increase the perceptivity of a driver, leading as a direct consequence to more relaxed mental stress of the same. One situation where we see potential in the application of such a system are merging areas on the expressway where two or more varying traffic streams converge into a single one. In order to reduce cognitive liabilities (in this work expressed as panic or anger), drivers are exposed to while merging, we have developed two behavioral rules. The first ("increased range of perception") enables drivers to change early upstream into a spare lane, allowing the merging traffic to join into mainline traffic at reduced conflicts, the second ("inter-car distance management" in the broader area of merging) provide drivers with recommendations of when and how to change lanes at the best. From a technical point of view, the "VibraSeat" a in-house developed car seat with integrated tactile actuators, is used for delivering information about perception range and inter-car distances to the driver in a way that does not stress his/her mental capabilities. To figure out possible improvements in its application in real traffic and at a meaningful scale, cellular automaton---based simulation of a specific section of Madrid expressway M30 was performed. Results from the data-driven simulation experiments on the true to scale model indicate that AmI technology has the potential to increase road throughput or average driving speed and furthermore to decrease the panic of drivers while merging into an upper (the main) lane.

Combining models and commodity chain research for making long-term projections of port throughput : an application to the Hamburg-le Havre range

Scipedia content — Tue, 16 Feb 2021 12:34:53 +0100

Long term projections of cargo throughput are indispensable for port development plans. Although commodity flow projections are useful for governments, port authorities, terminal operating companies and port users, scientific research on commodity flow projections for ports is limited. Existing studies generally use econometric models that assume stable relationships between growth of port throughput and such variables as GDP growth and trade growth. This paper presents a method that was developed as part of the Port Vision 2030 project of Port of Rotterdam Authority. The method combines a model with expert judgement and commodity specific research. This combination enables incorporating disruptions of past growth patterns. The contribution of this paper is the description of this method, its application to the volumes in 2030 of all major commodities handled in the Hamburg – Le Havre range, with four different scenarios, while most studies deal with a few commodities in one port, and often for a shorter period and with less scenarios. The results show that in all scenarios, total throughput is expected to rise, although in three scenarios not as fast as in the previous two decades. Furthermore, intermediates and container flows are expected to continue to grow, while throughput of raw materials (iron ore, crude oil) may decline.

Experimental measurement and Reynolds-averaged Navier–Stokes modelling of the near-field structure of multi-phase CO2 jet releases

Scipedia content — Tue, 16 Feb 2021 12:33:22 +0100

International audience; The deployment of a complete carbon capture and storage chain requires a focus upon the hazards posed by the operation of CO2 pipelines and intermediate storage vessels, and the consequences of accidental release. The aim of this work is the construction of a computational fluid dynamic model capable of accurately representing the complex physics observed in such a release, essential if dispersion phenomena are to be accurately predicted. The interacting thermo-physical processes observed include those associated with the rapid expansion of a highly under-expanded jet, leading to an associated sonic flow structure. In such a release, it is also possible for three phases to be present due to the expansion and subsequent Joule-Thomson cooling, and a suitable equation of state is required to elucidate a system's composition. The primary objective of this work is the consideration of these physical processes, and their integration into a suitable numerical framework which can be used as a tool for quantifying associated hazards. This also incorporates the validation of such a model using data available in the literature and also using that recently obtained, and presented here for the first time. Overall, the model has provided an excellent level of agreement with experimental data in terms of fluid and sonic structure and temperature measurements, and good agreement with respect to composition data.

Drinking water quality and formation of biofilms in an office building during its first year of operation, a full scale study

Scipedia content — Tue, 16 Feb 2021 12:33:07 +0100

Complex interactions existing between water distribution systems' materials and water can cause a reduction in water quality and unwanted changes in materials, aging or corrosion of materials and formation of biofilms on surfaces. Substances leaching from pipe materials and water fittings, as well as the microbiological quality of water and formation of biofilms were evaluated by applying a Living Lab theme i.e. a research in a real life setting using a full scale system during its first year of operation. The study site was a real office building with one part of the building lined with copper pipes, the other with cross-linked polyethylene (PEX) pipes thus enabling material comparison; also differences within the cold and hot water systems were analysed. It was found that operational conditions, such as flow conditions and temperature affected the amounts of metals leaching from the pipe network. In particular, brass components were considered to be a source of leaching; e. g. the lead concentration was highest during the first few weeks after the commissioning of the pipe network when the water was allowed to stagnate. Assimilable organic carbon (AOC) and microbially available phosphorus (MAP) were found to leach from PEX pipelines with minor effects on biomass of the biofilm. Cultivable and viable biomass (heterotrophic plate count (HPC), and adenosine triphosphate (ATP)) levels in biofilms were higher in the cold than in the hot water system whereas total microbial biomass (total cell count (DAPI)) was similar with both systems. The type of pipeline material was not found to greatly affect the microbial biomass or Alpha-, Beta- and Gammaproteobacteria profiles (16s rRNA gene copies) after the first one year of operation. Also microbiological quality of water was found to deteriorate due to stagnation.

Comparison of static vehicle flow assignment methods and microsimulations for a personal rapid transit network

Scipedia content — Tue, 16 Feb 2021 12:32:48 +0100

SUMMARY This article describes a static assignment method for a class of emerging public transport systems called personal rapid transit (PRT). PRT is a fully automated public transportation system where small-size vehicles run on exclusive guideways. Because of its automated, on-demand service, PRT must be able to automatically reroute empty vehicles after use to supply stations with waiting passengers. Consequently, any PRT traffic assignment must take into account the flow of empty vehicles as well as the flow of vehicles with passengers. The PRT assignment methods described in this work are based on linear programming models. One of the assignment methods has been applied to a realistic PRT network, and the statically assigned flows have been compared with averaged link flows produced by a PRT microsimulation. It is shown that the proposed static assignment method is not only useful to identify capacity bottlenecks of the planned PRT network but also serves to benchmark the microsimulator's vehicle management algorithms. Copyright © 2012 John Wiley & Sons, Ltd.

Adaptive calibration of (u,v)-wind ensemble forecasts

Scipedia content — Tue, 16 Feb 2021 12:30:15 +0100

Ensemble forecasts of (u,v)‐wind are of crucial importance for a number of decision‐making problems related to e.g. air traffic control, ship routeing and energy management. The skill of these ensemble forecasts as generated by NWP‐based models can be maximised by correcting for their lack of sufficient reliability. The original framework introduced here allows for an adaptive bivariate calibration of these ensemble forecasts. The originality of this methodology lies in the fact that calibrated ensembles still consist of a set of (space–time) trajectories, after translation and dilation. In parallel, the parameters of the models employed for improving the stochastic properties of the generating processes involved are adaptively and recursively estimated to accommodate smooth changes in the process characteristics and to lower computational costs. The approach is applied and evaluated based on the adaptive calibration of ECMWF ensemble forecasts of (u,v)‐wind at 10 m above ground level over Europe over a three‐year period between December 2006 and December 2009. Substantial improvements in (bivariate) reliability and in various deterministic/probabilistic scores are observed. Finally, the maps of translation and dilation factors are discussed. Copyright © 2012 Royal Meteorological Society

Traffic jam driving with NMV avoidance

Scipedia content — Tue, 16 Feb 2021 12:26:07 +0100

In recent years, the development of advanced driver assistance systems (ADAS) - mainly based on lidar and cameras - has considerably improved the safety of driving in urban environments. These systems provide warning signals for the driver in the case that any unexpected traffic circumstance is detected. The next step is to develop systems capable not only of warning the driver but also of taking over control of the car to avoid a potential collision. In the present communication, a system capable of autonomously avoiding collisions in traffic jam situations is presented. First, a perception system was developed for urban situations - in which not only vehicles have to be considered, but also pedestrians and other non-motor-vehicles (NMV). It comprises a differential global positioning system (DGPS) and wireless communication for vehicle detection, and an ultrasound sensor for NMV detection. Then, the vehicles actuators - brake and throttle pedals - were modified to permit autonomous control. Finally, a fuzzy logic controller was implemented capable of analyzing the information provided by the perception system and of sending control commands to the vehicles actuators so as to avoid accidents. The feasibility of the integrated system was tested by mounting it in a commercial vehicle, with the results being encouraging. © 2012 Elsevier Ltd. All rights reserved.

Peer Reviewed

Document type: Article

New directions for air traffic control simulators: A discussion to guide the selection and renovation of simulators

Scipedia content — Tue, 16 Feb 2021 12:25:39 +0100

WOS: 000317869800003

The authors have recent experience of the specification, procurement, customisation and operation of advanced air traffic control simulator systems. This paper summarises the specification of the software and hardware components of air traffic control simulators within a framework of user needs and advances in simulation technology. Both the required conventional characteristics and the desired innovative features which can accommodate future requirements are defined using taxonomy within this framework. Considering the high investments and challenges involved in the acquisition and operation of modem simulators, the proposed classifications and approaches will provide important benefits to users when selecting or renovating their systems.

Electric cars and wind energy

Scipedia content — Tue, 16 Feb 2021 12:22:20 +0100

To limit or, even better, reduce the emission of CO2 and the corresponding global warming effects, measures should be taken in the two most polluting economic sectors: the energy and transport sectors. The Netherlands has set goals to reduce CO2 emissions, in line with global and European initiatives. To reach this target, the electricity production sector should also use more renewables and the transport sector should take measures. In the electricity sector, the Netherlands wants to realize 10 GW of installed wind power in 2020; one of the initiatives for the transport sector is to have one million EVs (electric vehicles) in the same year. When EVs are powered with electricity from renewable sources, both sectors benefit: as such, we can 'kill two birds with one stone'. To study this, we researched the possible effects on the electricity system when introducing a large number of EVs and an increasing amount of wind power. The research presented models this for the 2020 Dutch situation. The study shows that the 2020 electricity system can cope with one million EVs and 10 GW of wind power, provided that EVs are charged using a load management regime that levels the nightly electricity demand. (C) 2012 Elsevier Ltd. All rights reserved.

Secondary suspension of railway vehicles - air spring modelling : Performance and critical issues

Scipedia content — Tue, 16 Feb 2021 12:17:04 +0100

This paper shows the importance of modelling the components of the suspension when performing dynamics simulations of a railway vehicle. Focusing on the air spring secondary suspension, a process to define an accurate component model is proposed based on a combination of laboratory tests and model identification techniques. Six models for the air spring secondary suspension are discussed and assessed based on comparison with experiments. "p"QC 20140604

Route planner for unmanned aerial system insertion in civil non-segregated airspace

Scipedia content — Tue, 16 Feb 2021 11:59:41 +0100

One of the most interesting challenges of the next few years will be airspace system automation. This process will involve different aspects such as air traffic management, aircraft and airport operations and guidance and navigation systems. The use of unmanned aerial system for civil missions will be one of the most important steps in this automation process. In this article, an air traffic management oriented conflict detection & resolution algorithm that models air traffic management operative technique as avoidance manoeuvres in order to self-separate the unmanned aerial vehicle from piloted air traffic is presented. As a first step, a geometric analysis identifies all possible unmanned aerial vehicle routes among the mission targets and related potential conflicts with piloted air traffic. For each potential conflict, air traffic management operative techniques are used to model different options of conflict resolution: vertical and horizontal avoidance, speed regulation, holding patterns and rerouting. The performances of a reference unmanned aerial vehicle are used to estimate the cost of each possible sub-route and, in case of conflict, the cost of each possible avoidance manoeuvre. In this way, the unmanned aerial vehicle mission is modelled as a combinatorial optimization problem that concerns the sequencing of both targets and conflict resolution options. As output, a conflict free route that minimizes the air traffic impact over the mission is provided. Simulation results over real air traffic data show how this approach could be useful for future common management of piloted and non-piloted air traffic.

A homogeneous relaxation flow model for the full bore rupture of dense phase CO2 pipelines

Scipedia content — Tue, 16 Feb 2021 11:50:55 +0100

International audience; The development of an homogeneous relaxation flow model for simulating the discharge behaviour following the full bore rupture of dense phase CO2 pipelines is presented. Delayed liquid-vapour transition during the decompression process is accounted for using an empirically derived equation for the relaxation time to thermodynamic equilibrium. The flow model's robustness is successfully demonstrated based on a series of hypothetical shock tube tests. Model validation on the other hand is performed by comparison of the predictions against experimental data obtained for the full bore rupture of realistic scale CO2 pipelines. Within the ranges investigated, it is found that although delayed phase transition effects have negligible impact on the pipeline decompression rate, ignoring such phenomena results in underestimating the transient discharge rate. This is important since the latter governs the minimum safety distances to CO2 pipelines and emergency response planning in the unlikely event of pipeline failure.

Electric cars and wind energy: Two problems, one solution? A study to combine wind energy and electric cars in 2020 in The Netherlands

Scipedia content — Tue, 16 Feb 2021 11:49:06 +0100

Emptying of Large-Scale Pipeline by Pressurized Air

Scipedia content — Tue, 16 Feb 2021 11:41:24 +0100

Emptying of an initially water-filled horizontal PVC pipeline driven by different upstream compressed air pressures and with different outflow restriction conditions, with motion of an air-water front through the pressurized pipeline, is investigated experimentally. Simple numerical modeling is used to interpret the results, especially the observed additional shortening of the moving full water column due to formation of a stratified water-air "tail". Measured discharges, water-level changes and pressure variations along the pipeline during emptying are compared using Control Volume model results. The CV model solutions for a non-stratified case are shown to be delayed as compared with the actual measured changes of flow rate, pressure and water level, but by considering water-column mass loss due to the water-air tail and residual motion, the calibrated CV model yields solutions that are qualitatively in good agreement with the experimental results. A key interpretation is that the long air-cavity celerity is close to its critical value at the instant of minimum flow acceleration. The influences of driving pressure, inertia and friction predominate, with the observed water hammer caused by the initiating downstream valve opening not significantly influencing the water-air front propagation. Keywords: Air-water interactions, Drainage, Experimentation, Pipes, Transient flow, Unsteady flow

Modal analysis of a cantilever beam by use of Brillouin based distributed dynamic strain measurements

Scipedia content — Tue, 16 Feb 2021 11:35:57 +0100

In this work we report an experimental modal analysis of a cantilever beam, carried out by use of a Brillouin optical time-domain analysis (BOTDA) setup operated at a fixed pump–probe frequency shift. The employed technique permitted us to carry out distributed strain measurements along the vibrating beam at a maximum acquisition rate of 108 Hz. The mode shapes of the first three bending modes (1.7, 10.8, 21.6 Hz) were measured for the structure under test. The good agreement between the experimental and numerical results based on a finite-element method (FEM) analysis demonstrates that Brillouin based distributed sensors are well suited to perform the modal analysis of a vibrating structure. This type of analysis may be useful for applications in structural health monitoring where changes in mode shapes are used as indicators of the damage to the structure.

What determines carpooling to workplaces in Belgium : location, organisation, or promotion

Scipedia content — Tue, 16 Feb 2021 11:33:53 +0100

Home to work travel remains the prime focus of mobility management policies, in which the promotion of carpooling is one of the main strategies. Besides governments, employers are key players in this strive for a more sustainable commute. However, commuting research tends to focus on individual commuters and their place of residence, rather than on workplaces and company-induced measures. Therefore, this paper takes the workplace as research unit to analyse the popularity of carpooling in Belgium. After an exploratory (spatial) data analysis, we incorporate three groups of factors in a multilevel regression model which predicts the share of carpooling at large workplaces: location (accessibility), organisation (activity sector), and promotion (carpool-oriented mobility management measures). Higher levels of carpooling are found at less accessible locations, and in the activity sectors construction, manufacturing and transport. This analysis gives insight in the determinants of carpooling, and may thus contribute to the development of sustainable transport policies.

Towards mapping land use patterns from volunteered geographic information

Scipedia content — Tue, 16 Feb 2021 11:26:39 +0100

large number of applications have been launched to gather geo-located information from the public. This article introduces an approach toward generating land-use patterns from volunteered geographic information (VGI) without applying remote-sensing techniques and/or engaging official data. Hence, collaboratively collected OpenStreetMap (OSM) data sets are employed to map land-use patterns in Vienna, Austria. Initially the spatial pattern of the landscape was delineated and thereafter the most relevant land type was assigned to each land parcel through a hierarchical GIS-based decision tree approach. To evaluate the proposed approach, the results are compared with the Global Monitoring for Environment and Security Urban Atlas (GMESUA) data. The results are compared in two ways: first, the texture of the resulting land-use patterns is analyzed using texture-variability analysis. Second, the attributes assigned to each land segment are evaluated. The achieved land-use map shows kappa indices of 91, 79, and 76% agreement for location in comparison with the GMESUA data set at three levels of classification. Furthermore, the attributes of the two data sets match at 81, 67, and 65%. The results demonstrate that this approach opens a promising avenue to integrate freely available VGI to map land-use patterns for environmental planning purposes.

Park-and-Ride motivations and air quality norms in Europe

Scipedia content — Tue, 16 Feb 2021 11:26:08 +0100

Transport congestion and the quality of the air in cities is a persistent concern for urban planners, and in this context Park and Ride (P. +. R) facilities have been proposed as an element of urban sustainability strategies in many cities in Europe. In 2008 a European Commission directive aimed at improving local air quality has been introduced, the Directive on air quality and cleaner air for Europe. It seems reasonable to suggest that increased regulatory measures at European level may have spurred interest in developing potential sustainable transport (policy) innovations such as P. +. R.We test this hypothesis through a survey among 25 cities in North-West Europe. We find that by 2010 perceived regulatory pressure for P. +. R has indeed increased compared to 2005, although it remains weak and is still not a significant motivation for P. +. R development. Furthermore, it was found that perceived community pressure has become a significant motivation, possibly because of increased public awareness and attention for global warming and sustainability. Overall we find that framing of P. +. R among urban planners as well as the cities' engagement levels have not evolved significantly from 2005 levels and thus that air quality concerns are an increasing but currently not strong motivation for local authorities in North-West Europe to develop P + R. © 2013 Elsevier Ltd.

Against the failures of risk regulation. Liability and safety in air traffic management (ATM)

Scipedia content — Tue, 16 Feb 2021 11:25:06 +0100

This article aims to analyse liability issues as a further means to regulate risks, in case the precautionary measures of the delivered safety system fail. Through liability, the risk that cannot be prevented can be transferred onto those parties who are in the best position to spread them. The allocation of liability thus works as an incentive to the correct functioning of the preventive measures. Liability rules appear to be a key legal remedy which can ensure both tort reparation and a fair and efficient distribution of burdens in a legal order. In this vein, air traffic management (ATM) is addressed as a case study, which shows the main issues and the gaps that liability rules face when dealing with the trade off between risk and safety as conveyed by technology."/jats:p""jats:p"After having clarified the nature of the relations between risk and liability on the one hand, and automation and liability on the other hand, this article analyses liability issues in the framework of ATM by approaching this topic in a comparative way between the National Airspace System (NAS) of the United States of America (USA) and the Single European Sky (SES) of the European Union (EU).

Six-port technology for traffic safety

Scipedia content — Tue, 16 Feb 2021 11:24:37 +0100

The market for driver-assistance systems for modern automobiles is rapidly growing. Formerly only provided for the luxury automotive market, these systems are nowadays more and more available for mid- and compact-class vehicles as well. This development is not only limited to the passenger car segment but is also more and more important for commercial vehicles and trucks. Some driving assistance systems have already become mandatory, e.g., the antilock breaking system (ABS). Some governments are currently thinking about requiring automatic distance control by law for heavy trucks. Automatic distance control in combination with an automatic emergency breaking system is one of the rising stars for enhancing traffic safety. Radar- based distance control mostly interacts with cruise control systems and it adapts the speed of the driver's car to the distance to the car or obstacle in front of the vehicle. Furthermore, unavoidable accidents are detected and actions for reducing the effects of the crash are automatically initiated for some systems. © 2012 IEEE.

Can a dysprosium shortage threaten green energy technologies?

Scipedia content — Tue, 16 Feb 2021 11:20:21 +0100

Dysprosium, one of the various rare earth elements, is currently for more than 99% mined in China. As China is reducing its exports, new mining projects outside of China are needed to sustain supply and meet future demands. Dysprosium is mainly used in permanent magnets to retain the magnet's strength at elevated temperatures. Therefore, the use of dysprosium doped permanent magnets is preferred in electric vehicles and direct-drive wind turbines. Based on four scenarios it could be shown that dysprosium demand will probably outstrip supply in the short term (up to 2020). Although new mines are being developed, it takes several years for them to become productive. For the long term it is expected that enough dysprosium oxide is available in the earth crust (which is economically feasible to mine with current dysprosium prices) to fulfil the projected demand of dysprosium up to 2050. Recycling of dysprosium can further secure dysprosium supply in the long term by reducing primary dysprosium use by 35% in 2050. Electric vehicles are likely to play a dominant role in future increases in dysprosium demand. Even with the limited market share in 2011, electric vehicles already contribute to 20% of dysprosium use.

NOx, fuel consumption and time effects of flight path angle during descent

Scipedia content — Tue, 16 Feb 2021 11:17:04 +0100

WOS: 000318575900001

Due to factors affecting flight operation and air traffic management, such as air traffic separation, avoidance of traffic from congested areas, or facilitating separation with crossing traffic, as well as environmental constraints, aircraft cannot always use optimum descent profiles and perform stair step descent or low level flight. This leads to vertical flight inefficiencies and thereby an increase in fuel consumption and NOx emissions. In order to address the negative impact of vertical flight inefficiencies, particularly in the descent phase, descending at constant flight path angles has been identified as an efficient approach procedure by aviation organizations and researchers. This procedure is defined as continuous descent approach. In this study, an evaluation of continuous descent approach and various flight path angles, in relation to conventional approaches, is investigated and the comparative results are given in terms of NOx emissions, fuel consumption, and descent duration. As a result, a strong inverse proportion between flight path angle and fuel consumption is found. As expected, an analogous strong inverse relationship is also found for flight path angle and NOx emissions, not only from reduced fuel usage, but also from the changed exhaust gas temperature due to lower power settings thanks to the continuous descent approach. It can also be seen that the descent duration could be less for steeper flight path angles.

The effects of different environmental conditions on thermoregulation and clinical and hematological variables in long-distance road-transported calves

Scipedia content — Tue, 16 Feb 2021 11:12:27 +0100

The aim of this study was to investigate the effects of long-distance road transport (19 h, from Poland to Italy) during 2 seasons (summer vs. win- ter) on clinical and hematological variables in calves. The environmental temperature range that could com- promise the thermoregulation system (thermal stress) of the calves was tested. For the 7 Holstein calves in each transport, the BW and rectal temperature (RT) were measured, and blood samples were collected at the farm of origin, before loading at the transit center (T2), after unloading at the farm of destination (T3), and 1, 2, 3, and 4 d after arrival. The body temperature (BT) and heart rate (HR) were continuously monitored from T2 to T3. The data were statistically analyzed according to a mixed model that considered the fixed effects of transport (repeated measurements), season of journey, and their interaction. Within the observed temperature-humidity index (THI) range (30 to 80), effective thermoregulation allowed the calves to main- tain their BT with small physiologic changes to pre- vent thermal stress, particularly in the summer. With no seasonal differences, the HR was greater at load- ing than unloading (120 vs. 115 beats per min; P = 0.012). As for the transport effect, the BW was less (P " 0.001) after unloading, and the RT was greater (P = 0.004). This effect was more marked in summer. The hematological variables indicated a moderate ef- fect of transport on the hydration condition, reactive and muscular systems, and metabolism, although he- matocrit (P = 0.004), erythrocytes, cortisol, NEFA, β-hydroxybutyrate, lactate, creatine kinase, lactate de- hydrogenase, and aspartate aminotransferase activity (P " 0.001), and total protein (P = 0.007) were greater after unloading. This was confirmed by a moderate decrease in total leukocytes (P = 0.031) and glucose concentration (P = 0.002). The changes in the clinical variables were similar for both seasons even though in the summer, hematocrit (P " 0.001), urea (P = 0.008), and total protein (P = 0.010) increased and glucose concentration (P = 0.038) decreased. In conclusion, the data did not show a pronounced effect attributable to the season of the journey. Long-distance road transport leads to notable changes in clinical and hematological variables at the end of the journey. However, these vari- ables remained within their physiological ranges and returned to basal values within a few days after the journey.

Impact of utility-based accessibility measures on urban public transportation planning: A case study of Denizli, Turkey

Scipedia content — Tue, 16 Feb 2021 10:58:30 +0100

it is considerably difficult to identify specific changes by using a single numeric parameter, improvements gained by a new urban public transport (UPT) facility or by an operation policy is still a challenge in the decision-making process with respect to transportation planning. Although some indicators such as service quality, capacity usage ratio, service kilometers, passenger kilometers or seat kilometers are used by planners and policy makers, these indicators may not always reflect the total gain of trip makers: to access a facility providing a specific utility. Thus, this study aims to evaluate accessibility measures as performance indicators in the UPT planning process. Three scenarios that consist of timetable regulation, central business district restriction and integration with bus rapid transit are investigated using accessibility perspective in addition to the conventional indicators obtained by using VISUM™ travel demand modeling software. The results show that the first scenario leads to a more effective UPT system in terms of accessibility. Hence, a more distinctive measure is obtained for the decision stage of UPT planning. © 2013 Elsevier Ltd.

Quercetin and flaxseed included in the diet of fattening lambs: Effects on immune response, stress during road transport and ruminal acidosis

Scipedia content — Tue, 16 Feb 2021 10:57:20 +0100

7 páginas, 5 tablas.

Thirty-two lambs were divided in 4 groups with 2 replicates each (8 batches in total) according to their body weights. The lambs were fed a total mixed ration (TMR) formulated either with palm oil (CTRL, 2 replicates, 4 animals per replicate; 34gpalmoilkg-1 TMR) or flaxseed (FS, 2 replicates, 4 animals per replicate; 85gflaxseedkg-1 TMR). Four more batches were fed the same TMRs but enriched with quercetin (QCT, 2 replicates, 4 animals per replicate, 34g palm oil plus 2gquercetinkg-1 TMR; FS-QCT, 2 replicates, 4 animals per replicate, 85g flaxseed plus 2gquercetinkg-1 TMR). Three weeks after starting with the experimental diets, the animals were immunized by a subcutaneous injection of ovalbumin, and blood samples were collected at days 0, 4, 9, 14 and 17 post-immunization to measure antibodies against ovalbumin. Afterwards, all of the lambs were subjected to a 4-h transportation-stress period to study the evolution of haematological and biochemical parameters during road transport and, finally, slaughtered. Mean ova-specific IgG titres were significantly lower in the lambs fed FS on days 14 and 17 when compared to CTRL group (FS×DAY, P=0.033). Additionally, FS reduced white blood cells counts and tissue damage (creatine phosphokinase, P"0.05) during road transport. Consequently, flaxseed showed some immunological properties and protection against tissue damage during road transport. Regarding ruminal acidosis, both quercetin and flaxseed seemed to be adequate to reduce the level of parakeratosis. © 2013 Elsevier B.V.

Financialsupportreceivedfrom ‘Consejería de Educación de la Junta de Castilla y León’ (ProjectCSI185B11-2)is gratefullyacknowledged.Julio Benavides,MaríaMartinez- Valladares,MaríaL.Tejido,Raúl Bodas,and NuriaPrieto (JAE-Doccontracts)were supportedbytheprogramme ‘Junta para la Ampliación de Estudios’ (CSIC-European SocialFund).

Peer Reviewed

Computational Fluid Dynamics Modeling of Corrugated Static Mixers for Turbulent Applications

Scipedia content — Tue, 16 Feb 2021 10:50:58 +0100

This work is aimed at investigating the capability of a fully predictive computational fluid dynamics (CFD) approach to catch the main features of the liquid flow in pipelines equipped with corrugated static mixer inserts. The simulations are based on the numerical solution of the Reynolds averaged Navier−Stokes equations on the three-dimensional domain closely representing the static mixer geometry. As a benchmark, literature experiments on a laboratory scale SMV mixer were considered and the simulation results obtained at different locations were compared with relevant velocity and tracer concentration data. The effect of the turbulence modeling, the near-wall treatment, and the numerical approximations on the accuracy of the results is discussed. The results analysis demonstrated that the selected CFD model can be reliably adopted to evaluate the velocity field and the mixing performances of turbulent flows in static mixers for design and optimization purposes. On the other hand, the application of the same model to an industrial scale corrugated plate mixer highlighted the effects of the distributor geometry and of the distance between consecutive elements on the mixing of two miscible liquids.

Long-term characteristics of simulated ice deformation in the Baltic Sea (1962-2007)

Scipedia content — Tue, 16 Feb 2021 10:50:12 +0100

[1] The North Atlantic Oscillation (NAO) index is a frequently used measure for the mean winter conditions in Northern Europe. A positive, high index is associated with strong westerlies and anomalous warm temperatures. The effects on sea ice conditions in the Baltic Sea are twofold. Warm temperatures prevent sea ice formation. If ice is present nevertheless, the strong winds can promote the formation of ice ridges which hinders ship traffic. We use an ocean-sea ice model to investigate the NAO impact on the ridged ice area fraction in the Baltic during 1962–2007. Our simulations indicate that in the northern Bothnian Bay, a high NAO index is related to an anomalous accumulation of ridges, while in the rest of the Baltic Sea, the relationship is contrary. The NAO explains locally at most only 20–25% of the ridged ice fraction interannual variability which indicates the systems complexity. However, we find high skill with local correlations around 0.8 for annually averaged ridged ice fraction reconstructed from multilinear regression using winter averaged wind extremes, surface air temperature, and sea surface temperature (SST). This suggests that the amount of ridged ice in late winter can be derived from these routinely measured quantities. In large parts of the basin, it is sufficient to use the atmospheric parameters as a predictor, while in the eastern Bothnian Bay and southern Gulf of Finland, the SST is required to reconstruct the bulk of the ridged ice fraction.

Effects of microplasma arc AISI 316L welds on the corrosion behaviour of pipelines in LiBr cooling systems

Scipedia content — Tue, 16 Feb 2021 10:47:29 +0100

[EN] The effect of microplasma arc welding (MPAW) on the electrochemical and corrosion behaviour of AISI 316L stainless steel tubes has been studied. Scanning electrochemical measurements were performed in sodium chloride to evaluate the difference in the electrochemical activity of base (non-welded) and welded samples. Oxygen reduction rates increase in AISI 316L due to the heat treatment effect induced by welding, indicating a higher electrochemical activity in the welded samples. Additionally, the use of MPA weldments in lithium bromide (LiBr) absorption machines was also analysed at typical operating temperatures and Reynolds numbers. The welding process increases corrosion rates, hinders passivation and increases the susceptibility to pitting attack in LiBr. However, zero-resistance ammeter and localization index measurements show that the galvanic pair generated between the base and welded alloys is weak, both electrodes being in their passive state. Temperature greatly affects the corrosion process. (C) 2013 Elsevier Ltd. All rights reserved. The authors would like to express their gratitude to the FPU grant given to Rita Sanchez Tovar, MICINN (CTQ2009-07518), to FEDER, to the Programa de Apoyo a la Investigacion y Desarrollo de la UPV (PAID-06-11-1864), to the Generalitat Valenciana for its help in the SECM acquisition (PPC/2011/013) and to Dr. Asuncion Jaime for her translation assistance. Sánchez-Tovar, R.; Montañés, M.; García-Antón, J. (2013). Effects of microplasma arc AISI 316L welds on the corrosion behaviour of pipelines in LiBr cooling systems. Corrosion Science. 73:365-374. https://doi.org/10.1016/j.corsci.2013.04.025 S 365 374 73

Congested Traffic Equilibria and Degenerate Anisotropic PDEs

Scipedia content — Tue, 16 Feb 2021 10:47:17 +0100

Congested traffic problems on very dense networks lead, at the limit, to minimization problems posed on measures on curves as shown in Baillon and Carlier (Netw. Heterog. Media 7:219–241, 2012 ). Here, we go one step further by showing that these problems can be reformulated in terms of the minimization of an integral functional over a set of vector fields with prescribed divergence as in Beckmann (Econometrica 20:643–660, 1952 ). We prove a Sobolev regularity result for their minimizers despite the fact that the Euler–Lagrange equation of the dual is highly degenerate and anisotropic. This somehow extends the analysis of Brasco et al. (J. Math. Pures Appl. 93:652–671, 2010 ) to the anisotropic case. Copyright Springer Science+Business Media New York 2013

A mechanistic model for pressure drops in corrugated plates static mixers

Scipedia content — Tue, 16 Feb 2021 10:46:03 +0100

In this work original experimental data and a simplified model for the prediction of pressure drops in pipelines equipped with static mixers are presented. The experimental data clarify the effect of the element length and of the relative position between two consecutive elements on the pressure drop. A significant reduction of the pressure drop is obtained by shortening the element length, while the relative position between consecutive elements has a minor importance. The experimental data are discussed and adopted for testing the proposed model reliability under various physical and geometrical conditions. The results show that the model, which is also compared with the available literature correlations, can be confidently applied to standard static mixers as well as to unconventional static elements arrangement, since it reliably accounts for the pressure drop variations due to changes in the geometrical configuration. The analysis is focused on static mixers for turbulent flow in pipelines, in particular the corrugated plate mixers.

A Survey on the Path Computation Element (PCE) Architecture

Scipedia content — Tue, 16 Feb 2021 10:45:37 +0100

Quality of Service-enabled applications and services rely on Traffic Engineering-based (TE) Label Switched Paths (LSP) established in core networks and controlled by the GMPLS control plane. Path computation process is crucial to achieve the desired TE objective. Its actual effectiveness depends on a number of factors. Mechanisms utilized to update topology and TE information, as well as the latency between path computation and resource reservation, which is typically distributed, may affect path computation efficiency. Moreover, TE visibility is limited in many network scenarios, such as multi-layer, multi-domain and multi-carrier networks, and it may negatively impact resource utilization. The Internet Engineering Task Force (IETF) has promoted the Path Computation Element (PCE) architecture, proposing a dedicated network entity devoted to path computation process. The PCE represents a flexible instrument to overcome visibility and distributed provisioning inefficiencies. Communications between path computation clients (PCC) and PCEs, realized through the PCE Protocol (PCEP), also enable inter-PCE communications offering an attractive way to perform TE-based path computation among cooperating PCEs in multi-layer/domain scenarios, while preserving scalability and confidentiality. This survey presents the state-of-the-art on the PCE architecture for GMPLS-controlled networks carried out by research and standardization community. In this work, packet (i.e., MPLS-TE and MPLS-TP) and wavelength/spectrum (i.e., WSON and SSON) switching capabilities are the considered technological platforms, in which the PCE is shown to achieve a number of evident benefits.

Extending prednisolone treatment does not reduce relapses in childhood nephrotic syndrome

Scipedia content — Tue, 16 Feb 2021 10:43:47 +0100

xtabstractProlonged prednisolone treatment for the initial episode of childhood nephrotic syndrome may reduce relapse rate, butwhether this results fromthe increased duration of treatment or a higher cumulative dose remains unclear.We conducted a randomized, double-blind, placebo-controlled trial in 69 hospitals in The Netherlands. We randomly assigned 150 children (9 months to 17 years) presenting with nephrotic syndrome to either 3 months of prednisolone followed by 3 months of placebo ( n=74) or 6 months of prednisolone (n=76), and median follow-up was 47 months. Both groups received equal cumulative doses of prednisolone (approximately 3360 mg/m2). Among the 126 children who started trial medication, relapses occurred in 48 (77%) of 62 patients who received 3 months of prednisolone and 51 (80%) of 64 patients who received 6 months of prednisolone. Frequent relapses, according to international criteria, occurred with similar frequency between groups as well (45% versus 50%). In addition, there were no statistically significant differences between groups with respect to the eventual initiation of prednisolone maintenance and/or other immunosuppressive therapy (50% versus 59%), steroid dependence, or adverse effects. In conclusion, in this trial, extending initial prednisolone treatment from 3 to 6 months without increasing cumulative dose did not bene fit clinical outcome in children with nephrotic syndrome. Previous findings indicating that prolonged treatment regimens reduce relapses most likely resulted from increased cumulative dose rather than the treatment duration. Copyrigh

Dimensions and determinants of expert and public attitudes to sustainable transport policies and technologies

Scipedia content — Tue, 16 Feb 2021 10:34:16 +0100

This paper investigates (a) attitudes to sustainable transport and how these differ between experts and non-experts, and (b) factors that influence these attitudes and their relevant importance in explaining why such differences occur. Attitudes of experts (N = 53) and British public (N = 40) were compared using open-ended questionnaires, attitude scales, analytic hierarchy process and preference ranking. Both samples prioritised reduction in transport demand in qualitative measures. In quantitative measures, however, experts preferred techno-economic measures while the public prioritised behaviour change and public transport improvement. Some options for sustainable transport also varied with individuals’ values, suggesting that expertise alone does not fully account for variation in attitudes. Different perspectives and values imply a need for a broader definition of expertise in transport policy-making, and that the public may not accept transport policies/technologies designed by experts – underlining the importance of early public engagement.

Employer Attitudes towards Peak Hour Avoidance

Scipedia content — Tue, 16 Feb 2021 10:28:36 +0100

Peak Hour Avoidance is a relatively new Dutch mobility management measure. To reduce congestion frequent car drivers are given a financial reward for reducing the proportion of trips that they make during peak hours on a specific motorway section. Although previous studies show that employers are not eager to support mobility management measures, employers are nevertheless an important stakeholder. They can provide their employees with alternatives such as other travel times, work locations or travel modes and encourage their use. This paper investigates the attitudes of Dutch employers towards Peak Hour Avoidance. Exploring the factors that influence these attitudes may help to fully utilise employer support. The data from 103 employers were collected through a web questionnaire. A structural equation model on the employer support for Peak Hour Avoidance was estimated. The results demonstrate that the size of the organisation and sector only have an indirect effect on the support for Peak Hour Avoidance. Results reveal that most support for Peak Hour Avoidance can be expected from organisations who feel responsible for influencing the commuting behaviour of employees, that have human resource managers with a positive attitude towards Peak Hour Avoidance, with flexible working times and that have already implemented mobility management measures. The largest contribution to PHA that can be expected from employers is providing employees with flexible working times and encouraging employees to fully utilise this option as an alternative for driving in peak hours. This would not only be beneficial for PHA but for a wide range of mobility management initiatives as well.

DNS as critical infrastructure, the energy system case study

Scipedia content — Tue, 16 Feb 2021 10:25:59 +0100

Modern critical infrastructures (e.g., power plants, energy grids, oil pipelines, etc.), make nowadays extensive use of information and communication technologies (ICT). As a direct consequence their exposure to cyber-attacks is becoming a matter of public security. In this paper, we analyse a particular infrastructure, rarely considered as source of threats, on which indeed the majority of network based services rely: the domain name system. Taking as example the power system, we show how deeply a failure (accidental or malicious) of the DNS might impact on the operation of the modern and distributed critical infrastructure.

Toward 4-D Trajectory Management in Air Traffic Control: A Study Based on Monte Carlo Simulation and Reachability Analysis

Scipedia content — Tue, 16 Feb 2021 10:22:44 +0100

One of the fundamental elements for the next generation in air traffic management systems, as envisioned by the Single European Sky Air Traffic Management Research Project and the Next Generation Air Transportation System Project, is 4-D trajectory management. In the contract-based air transportation system project, a novel concept of operations based on target windows (TWs) is developed. TWs are 4-D constraints imposed at different parts of the flight to increase predictability, efficiency, and safety. In this paper, we use Monte Carlo simulations and reachability analysis to evaluate some of these features of the TW concept. We start by using Monte Carlo methods to estimate the TW hitting probability and the probability of conflict. We then outline methods and computational tools based on reachability theory and highlight how they can be adapted to characterize the maneuvering freedom afforded by TWs. We also demonstrate how the reachability calculations can be used to guide conflict resolution in the presence of TW constraints. Our results indicate that TWs provide a promising balance between predictability of air traffic and maneuverability.

A stochastic games framework for verification and control of discrete time stochastic hybrid systems

Scipedia content — Tue, 16 Feb 2021 10:21:31 +0100

We describe a framework for analyzing probabilistic reachability and safety problems for discrete time stochastic hybrid systems within a dynamic games setting. In particular, we consider finite horizon zero-sum stochastic games in which a control has the objective of reaching a target set while avoiding an unsafe set in the hybrid state space, and a rational adversary has the opposing objective. We derive an algorithm for computing the maximal probability of achieving the control objective, subject to the worst-case adversary behavior. From this algorithm, sufficient conditions of optimality are also derived for the synthesis of optimal control policies and worst-case disturbance strategies. These results are then specialized to the safety problem, in which the control objective is to remain within a safe set. We illustrate our modeling framework and computational approach using both a tutorial example with jump Markov dynamics and a practical application in the domain of air traffic management.

The New Cispadana Motorway. Impact on Industrial Buildings Property Values

Scipedia content — Tue, 16 Feb 2021 10:21:18 +0100

Infrastructures, through externalities, modify the territorial status quo: by creating advantages and disadvantages, they lead to inequalities and territorial cohesion problems, calling for a setup of territorial equalization mechanisms. In this paper, the estimation of the costs and benefits generated from the building of the new Cispadana regional motorway (Emilia-Romagna Region, Italy) is described. The study focuses on the price variations of the industrial buildings property values in the real estate market after the new motorway will be built, aiming at developing a forecasting method, which could be repeatable and applicable to other kinds of externalities. Thanks to the hedonic pricing method, which is recurring in transport literature, using a multiple linear regression model based on ordinary least squares method (OLS), the contribution of the accessibility on the industrial buildings' pricing has been isolated; it was then possible to forecast the rise in the industrial buildings prices that will be due to the accessibility variation produced by the new infrastructure. The purpose of such a procedure is the setup of equalization mechanisms, which can re-balance the territorial effects though he so-called “land value capture” tools. Thanks to a relatively quick phase of development and implementation, the described application could be used as a tool for the ex-ante evaluation of different infrastructure projects and as an ex-post analysis tool for the monitoring of an existing infrastructure. Finally, thanks to the chance to understand the contribution of each territorial feature to the final price of the good, this application could be very useful in participatory planning processes because it could provide a common knowledge base which could be used to support the public administration’s capability of negotiation with the private partner, both in the participatory planning processes and in the public-private partnership procedures.

Small-scale modelling of the physiochemical impacts of CO2 leaked from sub-seabed reservoirs or pipelines within the North Sea and surrounding waters

Scipedia content — Tue, 16 Feb 2021 10:20:24 +0100

two-fluid, small scale numerical ocean model was developed to simulate plume dynamics and increases in water acidity due to leakages of CO2 from potential sub-seabed reservoirs erupting, or pipeline breaching into the North Sea. The location of a leak of such magnitude is unpredictable; therefore, multiple scenarios are modelled with the physiochemical impact measured in terms of the movement and dissolution of the leaked CO2. A correlation for the drag coefficient of bubbles/droplets free rising in seawater is presented and a sub-model to predict the initial bubble/droplet size forming on the seafloor is proposed. With the case studies investigated, the leaked bubbles/droplets fully dissolve before reaching the water surface, where the solution will be dispersed into the larger scale ocean waters. The tools developed can be extended to various locations to model the sudden eruption, which is vital in determining the fate of the CO2 within the local waters.

A Transportation Control System for Urban Environments

Scipedia content — Tue, 16 Feb 2021 10:19:27 +0100

Wireless technologies can help solve traffic congestions in urban environments, where road infrastructures develop slower than the sometimes exponential growth in the number of cars in traffic. We present a traffic control and congestion avoidance system developed over a vehicular ad-hoc network created between the cars in traffic and the road infrastructure. We propose a solution for monitoring traffic using not only sensors within the road infrastructure, but also the cars themselves acting as data collectors. The traffic control decision, provided by the road infrastructure, is scalable, load-balanced, and uses correction decisions for the route adjustment based on local areas. We present evaluation results that show the capabilities of the proposed congestion avoidance model.

When do global pipelines enhance the diffusion of knowledge in clusters?

Scipedia content — Tue, 16 Feb 2021 10:12:31 +0100

Recent studies have stressed the role played by global pipelines in fostering the growth of clusters and innovativeness. In this article, we develop a formal model to investigate when global pipelines contribute to an increase in local knowledge, depending on various characteristics of clusters such as size, knowledge endowment, and the ease of transmission of internal knowledge. This model is an extension of Cowan and Jonard’s (2004) model in which we introduce the concept of cluster and a role for spatial proximity in the diffusion of knowledge. Our results reveal that there is a natural tendency of actors within global pipelines to act as external stars, rather than gatekeepers of knowledge. Global pipelines are beneficial for the accumulation of knowledge only if the cluster is either characterized by a high-quality local buzz or is small and weakly endowed in terms of knowledge.

Enhancing urban resilience in face of climate change: a methodological approach

Scipedia content — Tue, 16 Feb 2021 10:11:57 +0100

Climate change can be considered as one of the main environmental topic of the 21st century (IPCC, 2011). It poses a serious challenge for cities all over the world (EEA, 2012): cities show, on the one hand a high level of vulnerability in face of climate change, on the other hand, they are responsible for 60% to 80% of global energy consumption and greenhouse gas (GHG) emissions, which represent the main causes of change in climate conditions."/p""p"In 2011, the 73% of European population was living in urban areas and the level of urbanization is expected to be at 82% by 2050 (UN, 2012). Due to the evidence that in Europe the 69% of all GHG emissions are currently generated by cities, larger and larger is the attention devoted, by scientific literature and policy makers, to outline strategies for urban adaptation to climate change, both at European and local scale."/p""p"Governments and scholars currently highlight the need for strengthening urban resilience in face of climate change and related consequences. By this perspective, some actions are already running, even though a clear identification of the features which make a city resilient in face of climate change is still missing."/p""p"To fill this gap, this contribution is mainly addressed to:"/p""p"- provide, by integrating different disciplinary perspectives, a conceptual model of the set of adaptive capacities and properties that characterize a resilient system;"/p"- verify, starting from a snapshot of current strategies and actions for urban adaptation currently implemented at European level, the consistency between those strategies and the identified set of resilience capacities and properties.

Step tolling with bottleneck queuing congestion

Scipedia content — Tue, 16 Feb 2021 10:06:28 +0100

In most dynamic traffic congestion models, congestion tolls must vary continuously over time to achieve the full optimum. This is also the case in . Vickrey (1969) 'bottleneck model'. To date, the closest approximations of this ideal in practice have so-called 'step tolls', in which the toll takes on different values over discrete time intervals, but is constant within each interval. Given the prevalence of step-tolling schemes they have received surprisingly little attention in the literature. This paper compares two step-toll schemes that have been studied using the bottleneck model by . Arnott et al. (1990) and Laih (1994). It also proposes a third scheme in which late in the rush hour drivers slow down or stop just before reaching a tolling point, and wait until the toll is lowered from one step to the next step. Such 'braking' behaviour has been observed in practice. Analytical derivations and numerical modelling show that the three tolling schemes have different optimal toll schedules and reduce total social costs by different percentages. These differences persist even in the limit as the number of steps approaches infinity. Braking lowers the welfare gain from tolling by 14% to 21% in the numerical example. Therefore, preventing or limiting braking seems important in designing step-toll systems. © 2012 Elsevier Inc.

Self-Directed Learning in Adaptive Training Systems: A Plea for Shared Control

Scipedia content — Tue, 16 Feb 2021 09:57:54 +0100

In the field of aviation, air traffic controllers must be able to adapt to and act upon continuing changes in a highly advanced technological work environment.

Seismic vulnerability of natural gas pipelines

Scipedia content — Tue, 16 Feb 2021 09:54:36 +0100

This work deals with the analysis of the interaction of earthquakes with pipelines transporting and distributing natural gas for industrial and civil use. To this aim, a new large data-set of seismic information classified on the basis of selected seismological, geotechnical and structural parameters is presented and analyzed. Particular attention is devoted to continuous pipelines under strong ground shaking, which is the geotechnical effect due to passage of waves in soil. Results are provided in terms of the likelihood of the loss of containment with respect to Peak Ground Velocity (PGV), a seismic intensity parameter which may be easily retrieved either from local authorities and public databases or from site dependent hazard analysis. Fragility functions and seismic intensity threshold values for the failure and for the loss of containment of gas from pipeline systems are also given. The obtained functions can be easily implemented in existing codes and guidelines for industrial risk assessment, land-use planning, and for the design of public distribution network, with specific reference to Natural - Technological interaction (Na-Tech). © 2013 Elsevier Ltd.

Corrosion of Pipe Steel in CO2 Containing Impurities and Possible Solutions

Scipedia content — Tue, 16 Feb 2021 09:52:20 +0100

CO2 flue gases acquired from different sources contain a significant amount of impurities and water, which are corrosive to the pipeline steel. To design the pipelines for large scale of CO2 flue gas transport, the corrosion of pipeline steels has to be investigated in the realistic conditions. In this paper, corrosion behaviour of steel S355 and stainless steel 316L in CO2 flue gas solutions has been investigated using electrochemical techniques in an autoclave. The corrosion rates of the steels in different environments were measured by polarization and mass loss measurements. The corrosion morphology and products on the steel surface were analyzed by photo- And electron microscope and x-ray diffraction, respectively. Three types of polymer coatings on the steel S355 have been studied in 3.5% NaCl solution plus CO2 in the autoclave at 100 bar and 60°C. The corrosion resistance of the coatings has been measured by electrochemical impedance measurements. The structures and the adhesion of the coatings before and after the autoclave tests have been investigated using microscope and pull-off test. The results show that the Coating B has better corrosion resistance than the other two types of coatings, which is a good candidate for internal coatings of a pipeline. © 2013 The Author.

On credibility improvements for automotive navigation systems

Scipedia content — Tue, 16 Feb 2021 09:52:06 +0100

utomotive navigation systems are becoming ubiquitous as driver assistance systems. Vendors continuously aim to enhance route guidance by adding new features to their systems. However, we found in an analysis of current navigation systems that many share interaction weaknesses, which can damage the system’s credibility. Such issues are most prevalent when selecting a route, deviating from the route intentionally, or when systems react to dynamic traffic warnings. In this work, we analyze the impact on credibility and propose improved interaction mechanisms to enhance perceived credibility of navigation systems. We improve route selection and the integration of dynamic traffic warnings by optimizing route comparability with relevance-based information display. Further, we show how bidirectional communication between driver and device can be enhanced to achieve a better mapping between device behavior and driver intention. We evaluated the proposed mechanisms in a comparative user study and present results that confirm positive effects on perceived credibility.

Two-dimensional water entry and exit of a body whose shape varies in time

Scipedia content — Tue, 16 Feb 2021 09:51:53 +0100

The two-dimensional water entry and exit of a body whose shape varies in time in a prescribed way is investigated through analytical and numerical modelling. For this purpose, an analytical model has been developed which extends the modified Logvinovich model of water impact to bodies with time-varying shape. A modified von Karman approach has been developed to describe the exit stage, and a rational derivation of the water exit model which is in use in offshore engineering is presented. CFD simulations are used to assess the accuracy of the analytical model. Several case studies of water entry and exit are presented. The analytical model provides very good force predictions during the entry stage in all cases, but the accuracy of the model in the exit stage depends on the maximum penetration depth. In particular, the appearance of high fluid forces on the body directed downward in both the entry and exit stages is remarkable.

Energetics, Security and the Sustainable Development of Cities

Scipedia content — Mon, 15 Feb 2021 12:21:08 +0100

Life in cities and its quality increasingly depends on transport means and on the energy used for their propulsion. A much discussed reason for the substitution of classical energy sources is also energy security; a second reason is the decreasing energetic returnability of oil. This paper draws attention to some aspects connected with accessibility to passenger transport in the city system. It is emphasized that the solution of the abovementioned problems takes into consideration many factors, not only those from the field of transportation. These factors influence one another; therefore it is necessary to find ways how to harmonize these factors for achieving the sustainable development of the city system. The sustainable city development is conditioned by the bearable development of the transport system so that access to various transport modes is ensured for all city inhabitants, and so the sustainable mobility of the city's inhabitants is ensured.

Document type: Article

A Study on the Model of Traffic Flow and Vehicle Exhaust Emission

Scipedia content — Mon, 15 Feb 2021 12:10:36 +0100

The increase of traffic flow in cities causes traffic congestion and accidents as well as air pollution. Traffic problems have attracted the interest of many researchers from the perspective of theory and engineering. In order to provide a simple and practical method for measuring the exhaust emission and assessing the effect of pollution control, a model is based on the relationship between traffic flow and vehicle exhaust emission under a certain level of road capacity constraints. In the proposed model, the hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) are considered as the indexes of total exhaust emission, and the speed is used as an intermediate variable. To verify the rationality and practicality of the model, a case study for Beijing, China, is provided in which the effects of taxi fare regulation and the specific vehicle emission reduction policy are analyzed.

Document type: Article

Probabilistic Method to Assess the Impact of Charging of Electric Vehicles on Distribution Grids

Scipedia content — Mon, 15 Feb 2021 11:00:20 +0100

This paper describes a grid impact analysis of charging electric vehicles (EV) using charging curves with detailed battery modelling. A probabilistic method using Monte Carlo was applied to a typical Spanish distribution grid, also using mobility patterns of Barcelona. To carry out this analysis, firstly, an IEEE test system was adapted to a typical distribution grid configuration

secondly, the EV and its battery types were modeled taking into account the current vehicle market and the battery characteristics

and, finally, the recharge control strategies were taken into account. Once these main features were established, a statistical probabilistic model for the household electrical demand and for the EV charging parameters was determined. Finally, with these probabilistic models, the Monte Carlo analysis was performed within the established scenario in order to study the lines’ and the transformers’ loading levels. The results show that an accurate model for the battery gives a more precise estimation about the impact on the grid. Additionally, mobility patterns have been proved to be some of the most important key aspects for these type of studies.

Document type: Article

A Review on Transit Assignment Modelling Approaches to Congested Networks: A New Perspective

Scipedia content — Mon, 15 Feb 2021 10:58:25 +0100

This paper reviews a number of studies on both frequency-and schedule-based transit assignment models that have been proposed by far, wherein various behavioural assumptions on a wide range of aspects are embedded. With a reinvestigation on the relationships and homogeneity between different modelling approaches, it explores the representative veins of the models, and thereby extends a new perspective to the existing reviews under a historical context. Meanwhile, both advantages and disadvantages of these methods are presented. On the strength of the analyses and discussions of the state-of-the-art transit assignment models, further research directions are suggested.

Document type: Article

Human’s Overtrust in and Overreliance on Advanced Driver Assistance Systems: A Theoretical Framework

Scipedia content — Mon, 15 Feb 2021 10:58:13 +0100

This paper gives a theoretical framework to describe, analyze, and evaluate the driver’s overtrust in and overreliance on ADAS. Although “overtrust” and “overreliance” are often used as if they are synonyms, this paper differentiates the two notions rigorously. To this end, two aspects, (1) situation diagnostic aspect and (2) action selection aspect, are introduced. The first aspect is to describe overtrust, and it has three axes: (1-1) dimension of trust, (1-2) target object, and (1-3) chances of observation. The second aspect, (2), is to describe overreliance on the ADAS, and it has other three axes: (2-1) type of action selected, (2-2) benefits expected, and (2-3) time allowance for human intervention.

Document type: Article

The influence of hearing loss on transport safety and mobility

Scipedia content — Mon, 15 Feb 2021 10:50:17 +0100

Purpose: To examine how road users with different degree of hearing loss experience safety and mobility in transport situations, compared to road users with normal hearing.Methods: A questionnaire ...

Document type: Article

Potential risk factors associated with contact dermatitis, lameness, negative emotional state, and fear of humans in broiler chicken flocks

Scipedia content — Mon, 15 Feb 2021 10:22:30 +0100

The objectives of this study were to 1) identify determinants of poor welfare in commercial broiler chicken flocks by studying the associations between selected resource-based measures (RBM, potential risk factors), such as litter quality and dark period, and animal-based welfare indicators (ABM), such as foot pad dermatitis and lameness, and 2) establish the breadth of effect of a risk factor by determining the range of animal welfare indicators associated with each of the risk factors (i.e., the number of ABM related to a specific RBM). Eighty-nine broiler flocks were inspected in 4 European countries (France, Italy, the United Kingdom, and the Netherlands) in a cross-sectional study. The ABM were contact dermatitis (measured using scores of foot-pad dermatitis and hock burn, respectively), lameness (measured as gait score), fear of humans (measured by the avoidance distance test and the touch test), and negative emotional state (measured using qualitative behavior assessment, QBA). In a first step, risk factors were identified by building a multiple linear regression model for each ABM. Litter quality was identified as a risk factor for contact dermatitis. Length of dark period at 3 wk old (DARK3) was a risk factor for the touch test result. DARK3 and flock age were risk factors for lameness, and the number of different stockmen and DARK3 were risk factors for QBA results. Next, the ABM were grouped according to risk factor and counted. Then, in a second step, associations between the ABM were investigated using common factor analysis. The breadth of a risk factor's effect was judged by combining the number (count) of ABM related to this factor and the strength of association between these ABM. Flock age and DARK3 appeared to affect several weakly correlated ABM, thus indicating a broad range of effects. Our findings suggest that manipulation of the predominant risk factors identified in this study (DARK3, litter quality, and slaughter age) could generate improvements in the related ABM and thereby enhance the birds’ overall welfare status.

Document type: Article

Characteristics of Heavily Edited Objects in OpenStreetMap

Scipedia content — Mon, 15 Feb 2021 10:20:15 +0100

This paper describes the results of an analysis of the OpenStreetMap (OSM) database for the United Kingdom (UK) and Ireland (correct to April 2011). 15; 640 OSM ways (polygons and polylines), resulting in 316; 949 unique versions of these objects, were extracted and analysed from the OSM database for the UK and Ireland. In our analysis we only considered “heavily edited” objects in OSM: objects which have been edited 15 or more times. Our results show that there is no strong relationship between increasing numbers of contributors to a given object and the number of tags (metadata) assigned to it. 87% of contributions/edits to these objects are performed by 11% of the total 4128 contributors. In 79% of edits additional spatial data (nodes) are added to objects. The results in this paper do not attempt to evaluate the OSM data as good/poor quality but rather informs potential consumers of OSM data that the data itself is changing over time. In developing a better understanding of the characteristics of “heavily edited” objects there may be opportunities to use historical analysis in working towards quality indicators for OSM in the future.

Document type: Article

Refrigeration logistics operations and perishable transport costs in groupage loads: an application for Spanish exports in Europe

Scipedia content — Mon, 15 Feb 2021 10:18:45 +0100

Creative Commons Attribution License [EN] In this paper, we analyze the current Spanish tariff system as applied by low-temperature distribution companies on transport in part loads of perishable freight that are destined to Spain’s main European export markets. Using 2008 data that have been directly obtained from a sample of transport companies, the price structure is formulated by making a distinction between ordinary and final prices and their respective variables. Next, the price structure is compared to the mean production costs. According to our calculations, we can state that the tariffs of distribution companies depend on the mean total cost, and they are estimated by using final prices calculated expressly for every customer. Finally, this paper outlines directions for future empirical work. [ES] Este trabajo analiza el sistema de tarificación aplicado en España por los operadores logísticos de frío (OLF) en el transporte de alimentos perecederos en carga fraccionada con destino a los principales mercados europeos de exportación. A partir de datos recabados en una muestra de OLF, se formula un modelo que posibilita la identificación de los componentes que integran el precio final. El análisis econométrico distingue en qué medida son relevantes dichos componentes y constata que los OLF tarifican según el coste total medio, empleando precios finales que calculan expresamente para cada cliente, dado que hay demandas de distinta intensidad a lo largo del año y trayectos con diferencias acusadas en los costes de producción. Andrés González-Moralejo, S. (2012). Refrigeration logistics operations and perishable transport costs in groupage loads: an application for Spanish exports in Europe. Ciencia e Investigación Agraria. 39(2):265-278. http://hdl.handle.net/10251/59741 S 265 278 39 2

Document type: Article

Design Optimization of Micro Air Launch Vehicle Using Differential Evolution

Scipedia content — Fri, 12 Feb 2021 16:11:59 +0100

In this paper, we have used the differential evolution to optimize the design of a Micro Air Launch Vehicle and its launch trajectory. Since trajectory design of a launch vehicle requires prior knowledge of the masses and propulsion performance parameters of the Micro Air Launch Vehicle, whereas the vehicle design requires prior knowledge of the required velocity (ΔV) to insert the required payload into the target orbit, a two-step optimization cycle was adopted. A Micro Air Launch Vehicle was designed to launch a 20-kg payload into a 400-km circular polar orbit. The preliminary design of the Micro Air Launch Vehicle was conducted given the required ΔV, which was obtained from trajectory optimization, and then applied in mission analysis to obtain the initial masses. These initial masses were used in the vehicle design to get the performance and geometry parameters. The objective function of the Micro Air Launch Vehicle design optimization is to minimize the initial mass under specified constraints on the insertion orbit. The objective of trajectory optimization is to maximize the payload mass under constraints on orbit specifications and design variables. For the 20-kg payload mass, the optimal initial mass is 1267.8 kg and optimal payload is 20.6 kg, which slightly exceeds the mission requirements.

Document type: Article

Pattern Analysis of Driver’s “Pressure-State-Response” in Traffic Congestion

Scipedia content — Fri, 12 Feb 2021 16:04:10 +0100

Traffic congestion, which has a direct impact on the driver’s mood and action, has become a serious problem in rush hours in most cities of China. Currently, the study about driver’s mood and action in traffic congestion is scarce, so it is necessary to work on the relationship among driver’s mood and action and traffic congestion. And the PSR (pressure-state-response) framework is established to describe that relationship. Here, PSR framework is composed of a three-level logical structure, which is composed of traffic congestion environment, drivers’ physiology change, and drivers’ behavior change. Based on the PSR framework, various styles of drivers have been chosen to drive on the congested roads, and then traffic stream state, drivers’ physiology, and behavior characters have been measured via the appropriative equipment. Further, driver’s visual characteristics and lane changing characteristics are analyzed to determine the parameters of PSR framework. According to the PSR framework, the changing law of drivers’ characteristics in traffic congestion has been obtained to offer necessary logical space and systematic framework for traffic congestion management.

Document type: Article

Sustainable Energy Alternatives Experimentation at SCT

Scipedia content — Fri, 12 Feb 2021 15:13:40 +0100

Sustained energy generation is very important for any region's economic growth either developed or developing. As the growth of the country depends on sustainable and efficient power generation management, in order to attain the sustainable energy generation, experimentation, and explorations in the latest avenues for these generations have to be carried out. In this paper an attempt is made to report the experimentation carried out at Salalah College of Technology (SCT) in terms of sustainable energy generation using alternate energy resources. Experimentation carried out at SCT for solar harnessing in sustainable transportation and wind energy alternatives for hybrid power generation at decentralized levels is tested. Experimentation results for individual experiments are not disclosed. Whereas the overall efficiency in using such alternate technologies for sustained power generation and comparisons with other likewise locations are reported in this paper.

Document type: Article

Level network performance with respect to IPv4 IPv6 networks with MPLS and RSV

Scipedia content — Fri, 12 Feb 2021 15:03:46 +0100

Este documento contiene información pertinente sobre el estado del arte de la Ingeniería de Tráfico (TE) MPLS (Multiprotocol Label Switching) y RSVP (Resource Reservation Protocol); también es importante como caso de estudio y porque da a conocer las técnicas utilizadas bajo la nueva versión de IPV6, en comparación con la versión IPV4. El objetivo es que sirva como marco de referencia para el estudio de la TE basada en la nueva versión de IPV6, específicamente en redes MPLS y RSVP, teniendo en cuenta las consideraciones pertinentes a la hora de tomar decisiones con respecto a la estabilidad del backbone y siendo la clave para proveedores de servicios de Internet que recientemente han estabilizado su infraestructura con IPV4. This paper contains relevant information of the state of art of traffic engineering, MPLS (Multiprotocol Lable Switching) and RSVP (Resource Reservation Protocol), as a case study and the techniques used under the new version of IPV6, against IPV4 version. The paper is intended to serve as a framework for the study of Engineering Traffic Based on the new version of IPV6, specifically MPLS and RSVP, taking into account relevant considerations necessary when making decisions regarding the stability of the Backbone remains the key to Internet service providers that have recently stabilized its IPv4 infrastructure.

Document type: Article

A graph-based approach for designing extensible pipelines

Scipedia content — Fri, 12 Feb 2021 15:00:10 +0100

Abstract"/p" "p"Background"/p" "p"In bioinformatics, it is important to build extensible and low-maintenance systems that are able to deal with the new tools and data formats that are constantly being developed. The traditional and simplest implementation of pipelines involves hardcoding the execution steps into programs or scripts. This approach can lead to problems when a pipeline is expanding because the incorporation of new tools is often error prone and time consuming. Current approaches to pipeline development such as workflow management systems focus on analysis tasks that are systematically repeated without significant changes in their course of execution, such as genome annotation. However, more dynamism on the pipeline composition is necessary when each execution requires a different combination of steps."/p" "p"Results"/p" "p"We propose a graph-based approach to implement extensible and low-maintenance pipelines that is suitable for pipeline applications with multiple functionalities that require different combinations of steps in each execution. Here pipelines are composed automatically by compiling a specialised set of tools on demand, depending on the functionality required, instead of specifying every sequence of tools in advance. We represent the connectivity of pipeline components with a directed graph in which components are the graph edges, their inputs and outputs are the graph nodes, and the paths through the graph are pipelines. To that end, we developed special data structures and a pipeline system algorithm. We demonstrate the applicability of our approach by implementing a format conversion pipeline for the fields of population genetics and genetic epidemiology, but our approach is also helpful in other fields where the use of multiple software is necessary to perform comprehensive analyses, such as gene expression and proteomics analyses. The project code, documentation and the Java executables are available under an open source license at "url"http://code.google.com/p/dynamic-pipeline"/url". The system has been tested on Linux and Windows platforms."/p" "p"Conclusions"/p" "p"Our graph-based approach enables the automatic creation of pipelines by compiling a specialised set of tools on demand, depending on the functionality required. It also allows the implementation of extensible and low-maintenance pipelines and contributes towards consolidating openness and collaboration in bioinformatics systems. It is targeted at pipeline developers and is suited for implementing applications with sequential execution steps and combined functionalities. In the format conversion application, the automatic combination of conversion tools increased both the number of possible conversions available to the user and the extensibility of the system to allow for future updates with new file formats.

Document type: Article

An energy concept for macroscopic traffic flow modeling

Scipedia content — Fri, 12 Feb 2021 14:43:36 +0100

International audience; Introduction The main differences between the deterministic macroscopic models are to be found in pressure expressions and representation of various phases observed experimentally. Methods In this paper, using the laws of fluid dynamics and thermodynamics to describe the traffic flow reality, a new expression of pressure is made and a second order model is proposed. Results It represents different traffic flow phases and, thus, conditions for transition between phases become clear. In addition, our approach suggests solutions to a number of problems yet to be resolved. Afterwards, simulations are presented which show some agreement with experimental data. Conclusion Finally, the proposed model highlights different types of possible actions for traffic flow control.

Document type: Article

Cuckoo Search Algorithm with Levy Flights

Scipedia content — Fri, 12 Feb 2021 14:31:59 +0100

During the last two decades, Continuous Network Design Problem (CNDP) has received much more attention because of increasing trend of traffic congestion in road networks. In the CNDP, the problem is to find optimal link capacity expansions by minimizing the sum of total travel time and investment cost of capacity expansions in a road network. Considering both increasing traffic congestion and limited budgets of local authorities, the CNDP deserves to receive more attention in order to use available budget economically and to mitigate traffic congestion. The CNDP can generally be formulated as bilevel programming model in which the upper level deals with finding optimal link capacity expansions, whereas at the lower level, User Equilibrium (UE) link flows are determined by Wardrop's first principle. In this paper, cuckoo search (CS) algorithm with Lévy flights is introduced for finding optimal link capacity expansions because of its recent successful applications in solving such complex problems. CS is applied to the 16-link and Sioux Falls networks and compared with available methods in the literature. Results show the potential of CS for finding optimal or near optimal link capacity expansions in a given road network. © 2013 Ozgur Baskan.

Document type: Article

The Distance Between Real Time Data and Decision Making in Urban Road Freight Transportation Systems; The Example of the City of Thessaloniki

Scipedia content — Fri, 12 Feb 2021 14:17:09 +0100

"jats:p" Road freight transport in urban areas (city logistics) is under study worldwide, especially during the last years, mainly due to its negative impacts to the environment and to the efficient operation of the road network. The modern approach to deal with this rising issue includes the deployment of strategies and measures that take into consideration the conditions prevailing in each study area. In order the decision makers to adopt the proper measures and define the strategy, it is vital for them to have full knowledge of the way an Urban Road Freight Transportation (URFT) system is organized and functions in the field. For this to happen, the decision makers must have under their disposal reliable real time data. After all URFT systems evolve through time and space and it is s crucial that the necessary data not only will be collected correctly but also they will be accessible anytime and anywhere. In this paper a new approach is proposed in order to achieve real time monitoring for URFT systems in order to provide the decision makers with all the necessary data for the case of Greece.

Document type: Article

Energy Consumption Prediction of a Vehicle along a User-Specified Real-World Trip

Scipedia content — Fri, 12 Feb 2021 13:41:51 +0100

Standard cycles provide an easy way to evaluate the energy consumption of vehicles, but it is the energy consumption that occurs on real-world trips that really matters to the driver and, to a larger extent, society. This study shows how digital maps and vehicle simulation tools can be used to estimate energy consumption on a real-world trip. The user (1) selects a trip in the mapping service ADAS-RP (Advanced Driver Assistance Systems Research Platform), (2) defines a vehicle model in the vehicle powertrain simulation tool Autonomie, and (3) runs and analyzes the simulation in that same tool. For each section of the trip, ADAS-RP provides various information that can include speed limits, historic data on traffic pattern speeds, the slopes of the routes, and the positions of stop signs and traffic lights. The first stage of processing this information is to schedule the stops and to create an intermediate speed target that takes those stops into account. The final driver demand speed includes transitions – accelerations and decelerations – between sections with different intermediate speed targets, or around stops. The ADAS-RP/Autonomie process is then used to compute the energy consumption of a hybrid electric vehicle and a conventional vehicle on 10 trips defined across the United States and Germany. The hybrid vehicle is more fuel efficient, especially on congested routes and routes with downhill slopes, the effect of which is analyzed in further detail.

Document type: Article

Highway to Success: The Impact of the Golden Quadrilateral Project for the Location and Performance of Indian Manufacturing

Scipedia content — Thu, 11 Feb 2021 14:42:22 +0100

We investigate the impact of the Golden Quadrilateral (GQ) highway project on the Indian organized manufacturing sector using enterprise data. The GQ project upgraded the quality and width of 5,846 km of roads in India. We use a difference-in-difference estimation strategy to compare non-nodal districts based upon their distance from the highway system. We find several positive effects for non-nodal districts located 0-10 km from GQ that are not present in districts 10-50 km away, most notably higher entry rates and increases in plant productivity. These results are not present for districts located on another major highway system, the North-South East-West corridor (NS-EW). Improvements for portions of the NS-EW system were planned to occur at the same time as GQ but were subsequently delayed. Additional tests show that the GQ project's effect operates in part through a stronger sorting of land-intensive industries from nodal districts to non-nodal districts located on the GQ network. The GQ upgrades further helped spread economic activity to moderate-density districts and intermediate cities. Document type: Preprint

SpaceBook D3.3.2 : Final Populated City Model Component

Scipedia content — Thu, 11 Feb 2021 14:21:32 +0100

QC 20140521 www.spacebook-project.eu

Internet inter-domain traffic engineering and optimizatioon

Scipedia content — Wed, 10 Feb 2021 09:20:18 +0100

Railway and sustainable transport development

Scipedia content — Wed, 10 Feb 2021 09:19:57 +0100

The potential of intelligent transport system (ITS) development in road transport of Hong Kong

Scipedia content — Wed, 10 Feb 2021 09:19:12 +0100

A study of the traffic congestion problem in Hong Kong : a case study of Wanchai district

Scipedia content — Wed, 10 Feb 2021 09:17:35 +0100

A study of safety in road transport in Hong Kong

Scipedia content — Wed, 10 Feb 2021 09:17:12 +0100

Sustainable transportation policy for Dhaka city, Bangladesh

Scipedia content — Wed, 10 Feb 2021 09:16:15 +0100

A sustainable transportation system in Hong Kong? : towards an Era of Ecological Modernisation

Scipedia content — Wed, 10 Feb 2021 09:15:47 +0100

The policy role of administrative tribunals : a study of the Air Transport Licensing Authority

Scipedia content — Wed, 10 Feb 2021 09:15:35 +0100

The role of electronic road pricing in tackling traffic congestion in Hong Kong

Scipedia content — Wed, 10 Feb 2021 09:15:19 +0100

Bus to bus interchange : solution for traffic congestion in Hong Kong Island

Scipedia content — Wed, 10 Feb 2021 09:15:05 +0100

Spatial perspective on sustainable transport under population decentralization : a case of Hong Kong

Scipedia content — Wed, 10 Feb 2021 09:14:50 +0100

Worldwide developments in air transport : liberalization and open skies concepts

Scipedia content — Tue, 09 Feb 2021 09:35:10 +0100

A study of the impact of SARS on air transport demand in Hong Kong : the case of Cathay Pacific Airways

Scipedia content — Tue, 09 Feb 2021 09:32:39 +0100

Cognition in the air : exploring and modeling expertise in air traffic control

Scipedia content — Tue, 09 Feb 2021 09:22:08 +0100

A study of the impact of SARS on air transport demand in Hong Kong : the case of Cathay Pacific Airways

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

Bicycle use and sustainable transport in Hong Kong : a case study of Shatin

Scipedia content — Tue, 09 Feb 2021 09:21:33 +0100