Scipedia: Documents published in 2018

Christchurch from air photo, LiDAR and satellite measurements regarding

Scipedia content — Tue, 16 Feb 2021 12:23:07 +0100

Recent earthquakes show that pipeline damage is severe in the areas where permanent ground deformations (e.g., liquefaction zones) occur. Ground movement hazard to pipeline systems can be assessed by using ground displacement measurements around the location of pipelines. There are many different ways of measuring ground displacements after an earthquake occur. This paper compares displacements measured in Avonside area, Christchurch, NZ, by using four different ways with respect to their effects on pipeline damage assessments. They are air photo, satellite, high resolution light detection and ranging (LiDAR) surveys data presented at 4- and 56-m grids acquired before and after the Mw6.2 22 February 2011 earthquake. Avonside area was in the liquefaction zones of the 22 February 2011 earthquake. Where possible, benchmark measurements were also included in the comparisons. In this study, the focus was on asbestos cement and cast iron water pipelines as the length of the pipelines and the number of damages in the study area was much higher compared to other pipe materials, providing sufficient repair rate data passing the screening criteria to develop linear regressions. The correlations between pipeline damage and lateral ground strains were developed by calculating the horizontal strains from these four different type displacements. The comparisons show that satellite imagery is good for estimating total movements but not so good for estimating lateral strains and conversely LiDAR surveys are not so good for estimating total movements, but much better for estimating lateral strains. Hence, pipeline damage correlations with LiDAR calculated strains provide higher determination coefficient (r2) value. The results of comparisons are presented and discussed. © 2018, Springer Science+Business Media B.V., part of Springer Nature.

Contact heat evoked potentials: Reliable acquisition from lower extremities

Scipedia content — Tue, 16 Feb 2021 12:21:57 +0100

Objective To investigate test-retest reliability of contact heat evoked potentials (CHEPs) from lower extremities using two different stimulation protocols, i.e., normal and increased baseline temperature. Methods A total of 32 able-bodied subjects were included and a subset (N = 22) was retested. CHEPs were recorded from three different dermatomes of the lower extremity (i.e., L2, L5, and S2). Test-retest reliability of CHEPs acquisition after simulation in various lower limb dermatomes using different stimulation protocols was analyzed. Results The study revealed an improved acquisition of CHEPS employing the increased baseline protocol, particularly when stimulating more distal sites, i.e., dermatome L5 and S2. Based on repeatability coefficients, CHEP latency (N2 potential) emerged as the most robust CHEP parameter. Although CHEP amplitudes (N2P2 complex) and pain ratings were decreased in the retest, amplitudes still showed fair to excellent intraclass correlation coefficients using normal baseline or increased baseline temperature, respectively. Conclusions This is the first study to demonstrate that CHEPs acquisition from the lower extremities is improved by increasing the baseline temperature of the thermode. Significance This study highlights the usability of CHEPs as a viable diagnostic method to study small fiber integrity.

Analysis of flight variability: A systematic approach

Scipedia content — Tue, 16 Feb 2021 12:20:36 +0100

In movement data analysis, there exists a problem of comparing multiple trajectories of moving objects to common or distinct reference trajectories. We introduce a general conceptual framework for comparative analysis of trajectories and an analytical procedure, which consists of (1) finding corresponding points in pairs of trajectories, (2) computation of pairwise difference measures, and (3) interactive visual analysis of the distributions of the differences with respect to space, time, set of moving objects, trajectory structures, and spatio-temporal context. We propose a combination of visualisation, interaction, and data transformation techniques supporting the analysis and demonstrate the use of our approach for solving a challenging problem from the aviation domain.

Detecting traffic congestion propagation in urban environments – a case study with Floating Taxi Data (FTD) in Shanghai

Scipedia content — Tue, 16 Feb 2021 12:19:51 +0100

Traffic congestion in urban environments has severe influences on the daily life of people. Due to typical recurrent mobility patterns of commuters and transport fleets, we can detect traffic congestion events on selected hours of the day, so called rush hours. Besides the mentioned recurrent traffic congestion, there are non-recurrent events that may be caused by accidents or newly established building sites. We want to inspect this appearance using a massive Floating Taxi Data (FTD) set of Shanghai from 2007. We introduce a simple method for detecting and extracting congestion events on selected rush hours and for distinguishing between their recurrence and non-recurrence. By preselecting of similar velocity and driving direction values of the nearby situated FTD points, we provide the first part for the Shared Nearest Neighbour (SNN) clustering method, which follows with a density-based clustering. After the definition of our traffic congestion clusters, we try to connect ongoing events by quer...

Comparing practice-ready forecast models for weekly and monthly fluctuations of average daily traffic and enhancing accuracy by weighting methods

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

Knowing daily traffic for the current year is recognized as being essential in many fields of transport analysis and practice, and short-term forecasting models offer a set of tools to meet these needs. This paper examines and compares the accuracy of three representative parametric and non-parametric prediction models, selected by the analysis of the numerous methods proposed in the literature for their good combination of forecast accuracy and ease of calibration, using real-life data on Italian motorway stretches. Non-parametric K-NN regression model, Gaussian maximum likelihood model and double seasonality Holt–Winters exponential smoothing model confirm their goodness to predict the weekly and monthly fluctuations of average daily traffic with varying degrees of performance, while maintaining an easy use in professional practice, i.e. requiring ordinary professional skills and conventional analysis tools. Since combining several prediction models can give, on average, more accuracy than that of the individual models, the paper compares two weighting methods of easy implementation and susceptible to a direct use, namely the widely used information entropy method and the less widespread Shapley value method. Despite being less common than the information entropy method, the Shapley value method proves to be more capable in better combining single forecasts and produces improvements in the predictions for test data. With these remarks, the paper might be of interest to traffic technicians or analysts, in various and not uncommon tasks they might find in their work. Keywords: Short-term traffic forecasting, Non-parametric regression, Gaussian maximum likelihood, Double seasonal Holt–Winters exponential smoothing, Entropy weighting method, Shapley value weighting method

Improvements on the liquefaction of a pipeline CO2 stream for ship transport

Scipedia content — Tue, 16 Feb 2021 12:10:21 +0100

Ship transport and pipeline transport of CO 2 are considered to be viable options for large scale CCS. While pipeline transport is usually recommended for shorter distances, ship transport might also be considered for these distances in the early stage of CCS due to its high flexibility and low capital expenses. Ship transport is usually carried out in liquefied state at a temperature around −50 °C and low pressures. Thus, an efficient liquefaction process is required. Unlike other works on CO 2 liquefaction, it is assumed that the CO 2 has been transported by pipeline before it is transported by ship. Consequently, the CO 2 is expanded instead of being compressed and purification is not necessary as it has already been carried out before pipeline transport. Basic 1-stage, 2-stage and 3-stage closed cycle liquefaction processes are modelled, showing that a significant reduction of the minimum specific energy demand can be obtained by employing a multi-stage cascade design. The energy demand for the 2-stage base process is approximately 39% lower than for the 1-stage process. The energy demand can be further reduced by approximately 13% with a 3-stage process. Four measures of optimisation have been analysed: For the CO 2 stream, energy recovery with a liquid expander and a two phase expander are investigated. For the refrigeration cycle, the use of an aftercooler and the replacement of the cascade heat exchanger by a phase separator is studied. It can be seen that the energy demand can be reduced by approximately 30%–40% with respect to the base process if those four measures are implemented. The impact of the optimisations is influenced by the impurity concentrations of the CO 2 stream. Besides liquefaction, the specific electrical and thermal energy demands for the injection of CO 2 have been calculated. The electrical energy demand is proportional to the wellhead pressure and was found to be between 1.9 kWh/t CO 2 and 7.8 kWh/t CO 2 . The thermal energy demand is between 21.0 kWh/t CO 2 and 30.5 kWh/t CO 2 , increasing for higher wellhead pressures and impurity concentrations. The research project is funded by the Federal Ministry for Economic Affairs and Energy (project number 03ET7031FC)

COPE: Interactive exploration of co-occurrence patterns in spatial time series

Scipedia content — Tue, 16 Feb 2021 12:09:19 +0100

Spatial time series is a common type of data dealt with in many domains, such as economic statistics and environmental science. There have been many studies focusing on finding and analyzing various kinds of events in time series; the term ‘event’ refers to significant changes or occurrences of particular patterns formed by consecutive attribute values. We focus on a further step in event analysis: discover temporal relationship patterns between event locations, i.e., repeated cases when there is a specific temporal relationship (same time, before, or after) between events occurring at two locations. This can provide important clues for understanding the formation and spreading mechanisms of events and interdependencies among spatial locations. We propose a visual exploration framework COPE (Co-Occurrence Pattern Exploration), which allows users to extract events of interest from data and detect various co-occurrence patterns among them. Case studies and expert reviews were conducted to verify the effectiveness and scalability of COPE using two real-world datasets.

Governance arrangements targeting diversity in Europe: how New Public Management impacts working with social cohesion

Scipedia content — Tue, 16 Feb 2021 12:03:43 +0100

This article analyses how policies to foster social cohesion within diverse and unequal urban contexts are affected by New Public Management and austerity policies. Based on the analysis of a handful of governance arrangements in three cities that differ in their institutional structure and diversity policy approaches (Copenhagen, Leipzig and Milan), it is shown that negative effects are quite widespread yet cushioned by a strong welfare state structure, solid local government and high priority given to the recognition of diversity. Nevertheless, the shift towards the application of market logic to social work reduces innovative potential, increases efforts spent on procedures and weakens public coordination. This article analyses how policies to foster social cohesion within diverse and unequal urban contexts are affected by New Public Management and austerity policies. Based on the analysis of a handful of governance arrangements in three cities that differ in their institutional structure and diversity policy approaches (Copenhagen, Leipzig and Milan), it is shown that negative effects are quite widespread yet cushioned by a strong welfare state structure, solid local government and high priority given to the recognition of diversity. Nevertheless, the shift towards the application of market logic to social work reduces innovative potential, increases efforts spent on procedures and weakens public coordination.

Organic traffic light control for urban road networks

Scipedia content — Tue, 16 Feb 2021 11:58:14 +0100

In recent years, autonomic and organic computing have become areas of active research in the informatics community. Both initiatives aim at handling the growing complexity in technical systems by focusing on adaptation and self-optimisation capabilities. A promising application for organic concepts is the control of road traffic signals in urban areas. This article presents an organic approach to traffic light control in urban areas that exhibits adaptation and learning capabilities, allowing traffic lights to autonomously react on changing traffic conditions. A coordination mechanism for neighbouring traffic lights is presented that relies solely on locally available traffic data and communication among neighbouring intersections, resulting in a distributed and self-organising traffic system for urban areas. The organic system's efficiency is demonstrated in a simulation-based evaluation.

Airport noise modelling for strategic environmental impact assessment of aviation

Scipedia content — Tue, 16 Feb 2021 11:56:12 +0100

projected by different agencies the aviation market will experience a significant increase in air traffic demand\\ud over the next decades, driven by the large demand of the Asia-Pacific region. To overcome the further deterioration\\ud of the quality of life of communities living around airports, the various aviation stakeholders are\\ud required to explore scenarios with different technology options, flight procedures, and fleet replacement strategies.\\ud Of course, the assessment of aviation scenarios must be addressed in a more integrated manner than\\ud hitherto, where noise, air quality and carbon release are considered. For such purpose, simplified airport noise\\ud models are required to overcome the important input data requirements and computation complexity of detailed\\ud airport noise models, and also to ensure compatibility against other environmental and economic models. This\\ud paper analyses the applicability and discusses the unavoidable limitations and advantages of existing simplified\\ud airport noise models within the context of multi-disciplinary strategic environmental impact assessment of\\ud aviation. Simplified airport noise models satisfying the above requirements and developed to be coupled with\\ud technology evaluators, e.g. Rapid Aviation Noise Evaluator (RANE) model (Torija et al., 2017), can inform policy\\ud decisions about which future technology platforms would be likely to be the most environmental efficient when\\ud considered holistically. Based on the specific conditions tested, the straight-out trajectory assumption and the\\ud use of generic aircraft types seem valid approximations for computing aviation noise outputs.

Segmented pipeline damage predictions using liquefaction vulnerability parameters

Scipedia content — Tue, 16 Feb 2021 11:49:35 +0100

Past observations showed that pipeline damages in liquefaction zones are significantly higher than the damages in areas where there was no liquefaction. Existing vulnerability relationships for the pipelines in liquefaction zones utilize parameters such as ground displacement, horizontal ground strain, angular distortion or both. These relationships are particularly useful in performance or risk assessment of pipeline systems. However, prediction of these parameters for pipeline damage estimates is difficult to perform and highly variable with current procedures. This paper proposes new correlations of asbestos cement (AC), cast iron (CI) and polyvinyl chloride (PVC) pipeline damage, expressed as repairs/km, with three different liquefaction parameters: liquefaction severity number (LSN), one-dimensional volumetric reconsolidation settlement (S-V1D), and liquefaction potential index (LPI). The pipeline damage data from 22 February 2011, Mw = 6.2 Christchurch earthquake and geotechnical information pertaining to liquefied area in Christchurch are utilized herein. Cone penetration test (CPT) based Boulanger and Idriss [1] liquefaction triggering procedure with 15th, 50th and 85th percentile cyclic resistance ratio (CRR) curves (corresponding to probabilities of liquefaction, PL, equal to 15%, 50%, and 85%) was used to calculate the parameters. It is shown that the relationships between AC, CI and PVC pipeline damages and LSN, S-V1D and LPI are strong, except for the correlation for AC pipeline damage versus LPI. Considering CI and PVC pipelines, both LSN and LPI correlations are comparable and slightly better than S-V1D correlations. Use of different probabilities of liquefaction triggering does not have significant effect on correlations with LSN and S-V1D whereas the same is not true for LPI correlations. Regarding the resilience of pipelines, PVC and AC pipelines performed the best and worst, respectively in all cases with CI pipelines in the middle. The correlations have the potential for use with existing or new liquefaction hazard maps for prediction of pipeline damage from future earthquakes. C1 [Toprak, Selcuk] Gebze Tech Univ, Dept Civil Engn, Kocaeli, Turkey. [Nacaroglu, Engin; Koc, Abdullah Cem; Manav, Yasemin] Pamukkale Univ, Dept Civil Engn, Denizli, Turkey. [van Ballegooy, Sjoerd; Torvelainen, Eric] Tonkin Taylor Ltd, 105 Carlton Gore Rd, Auckland 1023, New Zealand. [Jacka, Mike] Tonkin Taylor Ltd, 33 Parkhouse Rd, Christchurch 8042, New Zealand. [O'Rourke, Thomas Denis] Cornell Univ, Civil & Environm Engn Dept, Ithaca, NY 14853 USA.

CFD analysis of natural gas emission from damaged pipelines: Correlation development for leakage estimation

Scipedia content — Tue, 16 Feb 2021 11:46:30 +0100

Natural Gas (NG) leak may occur from either an above- or an under-ground pipeline, resulting in environmental and financial consequences. Although there are some relations for estimating the gas leak from an above-ground pipeline, there is no equation for the calculation of a buried pipeline leakage. The main objective of this work is to develop precise gas leak calculator equations for low- and medium-pressure buried pipelines. For this, an under-ground gas pipeline is numerically modeled considering the surrounding soil as a porous medium. Two- and three-dimensional models are used to investigate the gas leak through a hole intentionally made on the pipe. Pure methane, with a steady state, compressible and turbulent flow, is assumed through the pipe. The developed correlations are functions of the pipe diameter, the hole diameter, and the gas flow pressure. Comparison of the results with previous works in the field demonstrates that considering a one-dimensional model for the pipe and neglecting the length of the pipe after the hole causes up to 20% error. The results indicate that a two-dimensional model is not precise enough for estimating the gas leak from an under-ground pipeline (due to the soil resistance in three directions in a real situation). In addition, linear, second order and fourth order relations are observed between the amount of gas leak and the three effective parameters of the pipe entry pressure, the hole diameter, and the ratio of the hole diameter to the pipe diameter, respectively. Analysis of the results indicates that the relative difference between the results of the simulation and the results given by the developed correlations is within the range of ±7% for all cases.

Enhancing Cooperative Driving in IEEE 802.11 Vehicular Networks Through Full-Duplex Radios

Scipedia content — Tue, 16 Feb 2021 11:27:13 +0100

International audience; On the path to zero fatalities on the roadways, all vehicles have to periodically broadcast cooperative awareness messages (CAMs) in a timely and reliable manner, even in areas of high traffic density. The carrier senses multiple access with collision avoidance (CSMA/CA) scheme of IEEE 802.11, the de-facto standard for vehicular communications, is known to offer no reliability to broadcast packets that cannot be acknowledged, and to poorly perform at high network load due to collisions and interference. In this paper, an enhanced CSMA/CA protocol is analyzed for vehicular networks, which improves the CAM timeliness and reliability by leveraging full-duplex (FD) transceivers on board. FD devices can listen to the channel while transmitting, thus making collision detection viable. A FD vehicle can detect a CAM collision while sending, promptly abort the packet and retransmit it later. Results achieved through an analytical model under mathematically tractable assumptions, and through extensive system-level simulations in a complex urban environment, show the effectiveness of the protocol to cope with direct collisions, especially in high traffic areas, paving the way towards the realization of cooperative automated driving.

Combination of tradable credit scheme and link capacity improvement to balance economic growth and environmental management in sustainable-oriented transport development: A bi-objective bi-level programming approach

Scipedia content — Tue, 16 Feb 2021 11:22:15 +0100

In this paper, we propose a bi-objective bi-level programming model to balance economic growth and environmental management, which orients sustainable transport development by combining a tradable credit scheme (TCS) and a link capacity improvement measure. At the upper level, the decision maker aims to both maximize the economic benefit and minimize the total amount of traffic emissions by the optimal determination of a TCS and a link capacity improvement measure. The lower level is the user equilibrium problem, with elastic origin-destination (O-D) demand given the TCS and link capacity expansion measure. Further, a relaxation algorithm with a series of transformations is proposed to solve the proposed model. Numerical experiments illustrate the effectiveness of the proposed bi-objective bi-level model as well as the proposed relaxation algorithm. This study demonstrates how economic and environmental goals are influenced by the implementation of different development patterns comprising TCSs and link capacity improvements.

Estimation of network level benefits of reliability improvements in intermodal freight transport

Scipedia content — Tue, 16 Feb 2021 11:12:41 +0100

n important problem in the assessment of reliability benefits of transport projects is that link level improvements must be translated to network level, so that they can be economically valued based on users’ trips from origins to destinations. For intermodal transport, shipments follow a chain with more than one mode. Generally, this requires aggregation of travel time distributions that are not additive. We propose an approach that estimates the change in transport time reliability of an intermodal transport chain based on the changes for links of that chain. We demonstrate the framework of reliability assessment for a case study of network improvement for rail-truck intermodal transport in China. Also, we demonstrate the application in a cost-benefit analysis context with user valuations of transport reliabilities from the case at hand. The application leads to the result that projects for the renovation and expansion of the transshipment terminal perform better compared with project that improve rail haulage speed. Another finding is that the effect of reliability improvement projects can be super-additive at network level. In comparison with traditional methods, we conclude that the proposed method can better estimate transport time reliability benefits when the distribution of link travel times is highly skewed. Also, it opens new possibilities for further research for measuring correlated reliability measures within networks and for performing network resilience analysis.

Safety Management and the Concept of Dynamic Risk Management Dashboards

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

Risk management is considered as the core process of an effective safety management system for identifying hazards and assessing risks. However, recent fatal hull loss accidents appear to have resulted from a combination of factors, none of which can alone cause an accident or even a serious incident. Therefore, traditional safety risk assessment processes, risk matrices, hazard logs and conventional risk management methodologies that mainly address individual risks, in some cases remained less effective in preventing major accidents that resulted from cumulative risks. Consequently, air operators have the need not only to proactively identify the ‘initial’ and the ‘residual’ risk of a hazard, but also to recognize the ‘current’ or ‘actual’ risk state of their system and to take the necessary mitigation actions for preventing an accident or a serious incident that may result from a combination of factors. The aim of this paper is to present and explain the concept of Dynamic Risk Management Dashboards (DRMDs), a tool which is a combined, real-time basis, a cross-departmental effort for managing risks resulting from a combination of factors. DRMD could concurrently examine and visualize the actual risk state of an aerodrome, an aircraft, an aircrew or an air traffic route based on a set of pre-defined Risk Acceptance Criteria that have been developed and tailored by each operator. The DRMDs have been implemented and evaluated by the safety department of a large military aviation organization as a proactive safety tool that complements the existing risk management process. Anecdotal results after a six-month trial period showed that DRMD assist decision makers in identifying the cumulative risks of particular missions and effectively in responding to unacceptable risks before authorizing or dispatching a particular flight.

Analysing the trip and user characteristics of the combined bicycle and transit mode

Scipedia content — Tue, 16 Feb 2021 11:04:57 +0100

Several cities around the world are facing mobility related problems such as traffic congestion and air pollution. Although limited individually, the combination of bicycle and transit offers speed and accessibility that can compete with automobiles by complementing each other's characteristics. Recognising the potential benefits with regard to accessibility, health, and sustainability, several studies have investigated policies that encourage integration of these modes. However, the actual users and trips of the combined bicycle and transit mode have not been extensively studied empirically. This study addresses this gap by (i) reviewing empirical findings on related modes, (ii) deriving user and trip characteristics of the combined bicycle and transit mode in the Netherlands, and (iii) applying latent class cluster analysis to discover prototypical users based on their socio-demographic attributes. Most trips by this combined mode are found to be for relatively long commutes where transit is in the form of trains, and bicycle and walking are access and egress modes respectively. Furthermore, seven user groups are identified and their travel behaviour is discussed. Transport authorities may use these empirical results to further streamline integration of bicycle and transit for its largest users as well as to tailor policies to attract more travellers.

An empirical study into the factors that influence connection times at EV-charging stations

Scipedia content — Tue, 16 Feb 2021 11:01:41 +0100

This study is the first to systematically and quantitatively explore the factors that determine, the length of charging sessions at public charging stations for electric vehicles in urban areas, with, particular emphasis placed on the combined parking- and charging-related determinants of connection, times. We use a unique and large data set – containing information concerning 2.6 million charging, sessions of 64,000 (i.e., 60% of) Dutch EV-users – in which both private users and taxi and car sharing, vehicles are included; thus representing a large variation in charging duration behaviour. Using, multinomial logistic regression techniques, we identify key factors explaining heterogeneity in charging, duration behaviour across charging stations. We show how these explanatory variables can be used to, predict EV-charging behaviour in urban areas and we derive preliminary implications for policy-makers, and planners who aim to optimize types and size of charging infrastructure.

Impact of disruptive innovations on road transport strategy

Scipedia content — Tue, 16 Feb 2021 11:00:38 +0100

Scenario describing the future include many disruptive innovations, which implies that traditional models calibrated on historical data are not always applicable for quantification of these scenarios. This paper describes disruptive changes to be expected which will influence the reliability of forecasting approaches used for road transport assessments and which changes to these approaches can be recommended. Also adaptions to the forecasting framework are proposed and the key modelling issues to be improved are indicated. Some aspects will remain hard to predict and in these cases additional pro-active mitigation actions are recommended, such as flexibilization of the infrastructure and location policy for economic activities.

Developing Assessment Criteria for Sustainable Transport Appraisal

Scipedia content — Tue, 16 Feb 2021 10:56:55 +0100

Defining a clear, comprehensive, and non-overlapping set of assessment criteria is a crucial step in multi-criteria analysis processes. Although criteria are typically developed based on planning objectives, there currently exists no standard procedure for conducting this exercise when both transportation and wider sustainable development goals need to be considered jointly. Based on research applying the multi-actor multi-criteria analysis approach to the case of a high-speed rail project in the UK, this paper presents a framework and a replicable stakeholder involvement process for selecting, defining, and naming assessment criteria to be used in sustainable transport appraisal (STA). The framework consists of a set of systematic guidelines and considerations for producing a coherent list that addresses known cognitive biases and can be understood by a broad range of stakeholders. A further practicable outcome of the research is a comprehensive list, developed using this framework, of 28 transport assessment criteria encompassing direct project impacts, indirect societal impacts, and environmental impacts. This list can serve as a starting point for planners wishing to conduct MCA-based STA. One key take-away from this research is the emphasis on an inclusive, interactive, and iterative approach for defining sustainable transport assessment criteria.

Implications for the energy transition

Scipedia content — Tue, 16 Feb 2021 10:56:43 +0100

A key issue in smart grid visions is the integration of the energy and mobility systems. Electric vehicles (EVs) can be charged with renewable photovoltaic (PV) solar power, and contribute to the integration of solar power in the electricity network via vehicle-to-grid systems. In such systems the role of consumers becomes crucial as they both generate and store energy. We investigate differences between PV and EV adopter groups and the implications of these differences for the transition to smart energy systems. We study how socio-demographic characteristics of the consumer base influence regional diffusion patterns. In turn, we build scenarios to explore the influence of diffusion patterns on the viability of regional EV-PV integration in terms of energy use and regional self-consumption. The results point out large differences in the spatial diffusion patterns between EV and PV. These differences have implications for the transition to smart sustainable grids; vehicle-to-grid systems may not be viable for certain regions.

A variable quality of service model

Scipedia content — Tue, 16 Feb 2021 10:45:04 +0100

Reservations in daily services can improve user satisfaction, and give additional information about the demand patterns to the operators. However, providing reservations to carsharing clients is difficult. While carsharing is especially convenient if it is allowing one-way trips and vehicle drop-off anywhere in the service area (called free-floating), this flexibility increases management complexity because of vehicle stock imbalance. Most of the commercial providers of free-floating carsharing offer reservations under highly restrictive terms, for example only up to 30 min in advance. In this paper, we propose an innovative reservation enforcement technique that allows substantially longer reservation times while keeping the system profitable and achieving high service quality. A simple way to enforce reservations is locking vehicles until the departure time of a client. However, it comes at the cost of idling vehicles that could be used by other users and decreasing the revenue. Our approach, called relocations-based reservation enforcement method (R-BR) combines vehicle locking and relocation movements. It locks vehicles only a short time before the trip departure if a suitable vehicle is close enough due to the natural trip patterns. If no such vehicle is available, a car is relocated from another place. Further, we propose a variable quality of service (QoS) model in which the guaranteed radius around the user within which the reserved vehicle will be placed, and the maximum allowed reservation time before the departure depends on the zone of trip departure. A simulation-based optimization is used whereby the carsharing operation is simulated and optimized using an iterated local search (ILS) metaheuristic for adjustment of service level parameters. The proposed technique is tested on a set of artificial problem examples and a case study of a simulated working day in the Lisbon Municipality, Portugal. Results show that the proposed R-BR method is substantially better than the simple vehicle locking when the constant QoS approach is used and that the devised ILS metaheuristic can further increase the system performance, especially with high trip volumes.

Virus detection in high-throughput sequencing data without a reference genome of the host

Scipedia content — Tue, 16 Feb 2021 10:42:00 +0100

Discovery of novel viruses in host samples is a multidisciplinary process which relies increasingly on next-generation sequencing (NGS) followed by computational analysis. A crucial step in this analysis is to separate host sequence reads from the sequence reads of the virus to be discovered. This becomes especially difficult if no reference genome of the host is available. Furthermore, if the total number of viral reads in a sample is low, de novo assembly of a virus which is a requirement for most existing pipelines is hard to realize. We present a new modular, computational pipeline for discovery of novel viruses in host samples. While existing pipelines rely on the availability of the hosts reference genome for filtering sequence reads, our new pipeline can also cope with cases for which no reference genome is available. As a further novelty of our method a decoy module is used to assess false classification rates in the discovery process. Additionally, viruses with a low read coverage can be identified and visually reviewed. We validate our pipeline on simulated data as well as two experimental samples with known virus content. For the experimental samples, we were able to reproduce the laboratory findings. Our newly developed pipeline is applicable for virus detection in a wide range of host species. The three modules we present can either be incorporated individually in other pipelines or be used as a stand-alone pipeline. We are the first to present a decoy approach within a virus detection pipeline that can be used to assess error rates so that the quality of the final result can be judged. We provide an implementation of our modules via Github. However, the principle of the modules can easily be re-implemented by other researchers.

Modeling and fault diagnosis of flat inland navigation canals

Scipedia content — Tue, 16 Feb 2021 10:41:28 +0100

This article regards the development of an analytical redundancy-based approach for detecting and isolating both sensor and actuator faults in flat inland navigation canals. Inland navigation networks are principally used for transport and are composed of many canalized natural rivers and artificial canals characterized by no slope. These canals are strongly affected by resonance phenomena, which can create waves such that the navigation condition might not be guaranteed. It is, therefore, required to ensure dealing with fault-free measured data and actuators. The proposed approach is based on the integrator delay zero model of the flat inland navigation canal. The proposed method is tested by considering the Cuinchy–Fontinettes navigation reach (in the north of France) to detect and isolate the occurrence of faults in the Cuinchy and Fontinettes level sensors and in the Cuinchy gate.

This work has been partially funded by the Spanish Ministry of Economy and Competitiveness (MINECOP) and FEDER through the project HARCRICS (ref. DPI2014-58104- R) and through the grant IJCI-2014-20801.

Peer reviewed

Planning low carbon urban-rural ecosystems: An integrated transport land-use model

Scipedia content — Tue, 16 Feb 2021 10:38:19 +0100

As urbanization gradually modifies natural ecosystems and affects environmental sustainability, urban spatial planning can be used as a tool to address to Urban Metabolism and meet sustainable development targets. The concentration of people in urban areas makes these increasingly requiring for primary products and services as food and energy, and the fulfilment of such needs result in significant carbon emissions. The inclusion of spatial functions as agriculture and renewables in the urban planning can address to this environmental impact, but would require support-planning tools able to explore new land-use allocation strategies within an integrated urban-rural ecosystem. In this paper, we propose an optimization framework for the planning of low carbon urban-rural ecosystems that integrates transport and land-use planning and cope with urban metabolism, involving urban mobility, food transportation, energy supplies. This framework contributes to the literature as it formulates a network between urban, agricultural, energy, and carbon mitigation land-covers and optimizes the horizontal carbon fluxes within an integrated urban-rural environment. In order to minimize carbon emissions by mobility and resources (i.e. food) transportation, the framework aids identifying trade-offs between accessibility and density over the spatial distribution of resource-generating and resource-consuming land-covers. Proof of concept is provided with a realistic numerical example, propelled by real-world data from an Italian region. The land-use allocation solution makes the exemplifying urban-rural ecosystem behaving as carbon sink due to the established green areas and the configuration of the spatial uses. A sensitivity analysis is finally carried out to assess the impacts of mobility and resources transportation on the spatial urban-rural structure and associated carbon emissions. It comes out that the optimal urban configuration to mitigate carbon emissions from transportation integrates urban and rural uses and guarantees accessibility to several functions as cultivated areas, renewables and green covers, responsible to provide food, energy and air cleaning respectively to dwellers.

Novel DC Bias Suppression Device Based on Adjustable Parallel Resistances

Scipedia content — Tue, 16 Feb 2021 10:37:43 +0100

For lack of the appropriate global distribution of dc currents, the conventional suppression method to suppress dc bias based on capacitive dc blocking device (BD) redirects current to the ground as much as possible, which predisposes to the exceeding neutral current of other transformers in the regional power grid and leads to the contradiction between the power grid corporation and other public enterprises. Therefore, this paper presents a flexible suppression method for dc bias based on a novel dc-bias suppression device. First, a current balancing device (CBD) based on adjustable parallel resistances is designed. The mathematical model for global optimal switching of CBDs is established by a field-circuit coupling method with the equivalent resistance network of an ac system along with the location of substations and ground electrodes. The optimal switching scheme to minimize the global maximum dc current is obtained by gravitational search algorithm. Based on the aforementioned work, we propose a suppression strategy considering electro-corrosion of metal pipelines. The effectiveness and superiority of suppression methods are verified by comparative case studies of the Yichang power grid.

The Construction of Flow in and through Radio Traffic Reports

Scipedia content — Tue, 16 Feb 2021 10:35:24 +0100

With the rise of privatized automobility and the increase of traffic jams, new sociotechnical systems have emerged that aim at traffic control. Radio traffic information has been a key element in these systems. Through a qualitative analysis of historical radio broadcasts of the largest Dutch news station between 1960 and 2000, this article explores the changing format and content of traffic information updates. I will show how the rather formal, detailed, and paternalistic narratives of the traffic reports in the 1960s gave way to more informal, witty, yet flow-controlling traffic information discourse in later decades. I will explain the dynamics involved by drawing on mobility and media studies and by developing two distinct notions of flow, one of which builds conceptually on Raymond Williams’s work on mobile privatization, the other is grounded in the field of traffic management. In so doing, this article aims to contribute to a better understanding of the role of public radio broadcasts in our world of privatized automobility.

Network Model for Optimal Aircraft Location for Human Organ Transportation Activities

Scipedia content — Tue, 16 Feb 2021 10:34:29 +0100

Background The efficiency of transport phases is a key factor in successful organ transplant operations. Reliability, safety, and punctuality must be in compliance with the European Union and national frameworks and be consistent with economic, quantitative, and level-of-service parameters. In this study we investigated the optimal numbers and locations of aircraft in the Italian territory by comparing performance indexes related to different time intervals and service design scenarios. Methods An integer linear programming model is described as an optimal service solution for covering the demand for extraregional organ transport by air between June 2015 and May 2016. Restrictions on aircraft utilization and actual length of the missions in cases of incompatible activities are the relevant input data of the model. Results Based on mission durations and their origin and destination, the model returns the optimal number and location of aircraft in various scenarios. The performance parameters required by law and the need to guarantee the service from/to the whole territory, together with the transplant figures performed and transplant center locations, have been taken into account to determine the most efficient spatial and numerical allocation. Conclusion The efficient design of an urgency-based service such as the transportation of organs for transplant purposes is not an easy task. Nevertheless, knowledge of the logistic chain and continuous monitoring and update of data and performance parameters can allow for collection of useful information to guarantee a high-performing service.

Congested urban areas with high interactions between vehicular and pedestrian flows: A cost-benefit analysis for a sustainable transport policy in Naples, Italy

Scipedia content — Tue, 16 Feb 2021 10:33:03 +0100

Introduction/Methods:"/jats:title""jats:p"A significant application of the Sustainable Urban Mobility Plan of Naples, in southern Italy, will be described with specific reference to design a sustainable transport scenario for one of the highest density and congested area of the city: Municipio square, in the centre of Naples, where the homonymous station of the Metro Line 1 was under construction. The particularity of this case study is that Municipio Square is a high dense population area characterized by multimodal traffic flows (vehicles and pedestrians) and a thousand of travellers who embark/disembark every day from the marina to the islands of the Naples Gulf ("jats:italic"e.g."/jats:italic"Capri, Ischia) and cruises around the Mediterranean Sea. Thousands of vehicles and people pass through the square every day, often slowing the vehicular flows."/jats:p""jats:p"Starting from these considerations, a multi-scale modelling architecture (estimated"jats:italic"ad-hoc"/jats:italic"for the specific case study) was proposed to better evaluate policy impacts ("jats:italic"e.g."/jats:italic", transport, social, environmental), applying both macroscopic and microscopic simulation models simultaneously to design a sustainable transport scenario in term of both geometrical and traffic solutions."/jats:p""/jats:sec""jats:sec""jats:title"Results:"/jats:title""jats:p"Six different design scenario were compared and the main results of the most significant one are described and discussed. The best project solution reduces the average travel time and the long queues thanks to a better distribution of the flows (both vehicles and pedestrians) in the broader area around of Municipio square. The simulation results also underlined the benefits for pedestrians related to the presence of different size of sidewalks and paths."/jats:p""/jats:sec""jats:sec""jats:title"Conclusion:"/jats:title""jats:p"Because of the realization of the new metro station will increase the pedestrian flows, the external layout of the square was designed, regarding infrastructures and paths, to minimize the conflicts and reduce the overall travel time. The proposed sustainable transport scenario was conceived in term of best geometrical devices and traffic solutions."/jats:p""jats:p"Finally, a cost-benefit analysis was also proposed, according to the European guidelines, aiming in improving transport, urbanistic, artistic/cultural, aesthetic, economic and environmental aspects as well as liveability for citizens, transport users (public and private) and tourists."/jats:p""/jats:sec

Computed tomography analysis of impact response of lightweight sandwich panels with micro lattice core

Scipedia content — Tue, 16 Feb 2021 10:32:13 +0100

One of the main focuses in transportation engineering is the application of sandwich materials in order to create safer and efficient vehicles. The main focus of this study was the application of 3D computed tomography for analyzing the responses of sandwich panels with micro lattice core subjected to impact loading. Micro lattice specimens were manufactured using Ti-6Al-4V powder by means of a direct metal laser sintering system. A theoretical model was applied for predicting the failure initiation loads under impact loading. The predictions presented good consistency with the experimental measurements. The 3D computed tomography system was used for the analysis of the collapse modes of the micro lattice sandwich panels after low-velocity impact tests. Experimental and theoretical results proved that lightweight sandwich panels with micro lattice cores are excellent energy absorbers and, therefore, they could have significant applications in the transportation industry. © 2018, © IMechE 2018.

Train-Network Interactions and Stability Evaluation in High-Speed Railways-Part I:Phenomena and Modeling

Scipedia content — Tue, 16 Feb 2021 10:30:21 +0100

This paper presents an impedance-based model to systematically investigate the interaction performance of multiple trains and traction network interaction system, aiming to evaluate the serious phenomena, including low-frequency oscillation (LFO), harmonic resonance, and harmonic instability. The train-network interaction mechanism is therefore studied, and one presents a detailed coupling model for investigating the three interactive phenomena and their characteristics, influential factors, analysis methods, and possible mitigation schemes. In Part I of the two-part paper, the measured waveforms of such three phenomena are first characterized to indicate their features and principles. A unified framework of the train-traction network system for investigating the three problems is then presented. In order to reveal the interaction mechanism, all-frequency impedance behaviors of the electric trains and traction network are equally modeled. In which, an impedance-based input behavior of the train is fully investigated with considering available controllers and their parameters in DQ-domain. The entire traction network, including traction transformer, catenary, supply lines, is represented in a frequency-domain nodal matrix. Furthermore, the impedance-frequency responses of both electric train and traction network are measured and validated through frequency scan method. Finally, a generalized train-network simulation and experimental system are conducted for verifying the theoretical results of the two-part paper.

Causal Relationship Between Air Transport and Economic Growth: Evidence from Panel Data for High, Upper-Middle, Lower-Middle and Low-Income Countries

Scipedia content — Tue, 16 Feb 2021 10:19:57 +0100

Kiraci, Kasim/0000-0002-2061-171X; BAKIR, Mahmut/0000-0002-3898-4987

WOS: 000510158200002

This study aims to find out the causal relationship between air transport and economic growth based on income level. To this end, selected countries with high-income, upper-middle-income, lower-middle-income, and low-income levels were included in the analyses for this study. Focusing on the 1990-2016 period, a total of 70 countries were classified according to their income levels and were analyzed empirically. in the study, panel causality analyzes by Konya (2006) and Emirmahmutoglu & Kose (2011) were used. Our findings show that GDP has a certain degree of effect on air transport. They also indicate that the unidirectional or bidirectional causal relationships running from GDP to air transport and air transport to GDP vary by the income level of countries.

A novel paradigm for a sustainable mobility based on electric vehicles, photovoltaic panels and electric energy storage systems: Case studies for Naples and Salerno (Italy)

Scipedia content — Tue, 16 Feb 2021 10:15:28 +0100

The paper presents an in-depth analysis of a novel scheme for the sustainable mobility, based on electric vehicles, photovoltaic energy and electric energy storage systems. The work aims to analyse such innovative system, putting in evidence its advantages in comparison to a conventional one, based on the grid-to-vehicle technology. The study also provides interesting guidelines for potential users and system designers. Two case studies are presented: i) the taxi fleet of the city centre of Naples and ii) the cargo vans of the city of Salerno; both towns are in Southern Italy. For each case, the hourly power consumption of the vehicles was evaluated, as a function of the daily trip length. An accurate procedure was implemented to select the sites suitable for the installation of the charging stations, including a photovoltaic field and an electric storage system. A comparison was also performed between two different electric storage technologies: lead-acid and lithium-ion battery. The case studies were analysed by means of a detailed dynamic simulation model, developed in TRNSYS. A sensitivity analysis was also performed, to evaluate how different values of the most important design and operating parameters affect the system overall performance. It was found that the results are mostly affected by solar field area, capacity of the energy storage system and investment cost. The comparison between the two selected storage technologies did not exhibit significant differences. For both the cases investigated, it was found that, during the summer, solar energy covers an important amount of the total energy demand. On the contrary, in winter the amount of energy provided by the public electric grid was high. From an economic point of view, assuming a lithium-ion battery capital cost equal to 90 €/kWh, acceptable pay-back periods (about 6 years) were obtained, for both the applications considered.

Optimizing the valorization of industrial by-products for the induction healing of asphalt mixtures

Scipedia content — Tue, 16 Feb 2021 10:07:06 +0100

Self-healing within asphalt pavements is the process whereby road cracks can be repaired automatically when thermal and mechanical conditions are met. To accelerate and improve this healing process, metal particles are added to asphalt mixtures. However, this approach is costly both in economic and environmental terms due to the use of virgin metallic particles. So, even though the self-healing of asphalt mixtures has been widely addressed in experimental terms over the years, there is a lack of research aimed at modelling this phenomenon, especially with the purpose of optimizing the use of metal particles through the valorization of industrial by-products. As such, the goal of this study was to develop a statistical methodology to model the healing capacity of asphalt concrete mixtures (AC-16) from the characteristics of the metal particles added and the time and intensity used for magnetic induction. Five metal particles were used as heating inductors, including four types of industrial by-products aimed at transforming waste products into material for use in the road sector. The proposed approach consisted of a combination of cluster algorithms, multiple regression analysis and response optimization, which were applied to model laboratory data obtained after testing asphalt concrete mixtures containing these inductors. The results proved the accuracy of the statistical methods used to reproduce the experimental behaviour of the asphalt mixtures, which enabled the authors to determine the optimal amount of industrial by-products and time needed to make the self-healing process as efficient as possible.

ViLDAR-Visible light sensing-based speed estimation using vehicle headlamps

Scipedia content — Tue, 16 Feb 2021 10:03:24 +0100

The introduction of light emitting diodes (LED) in automotive exterior lighting systems provides opportunities to develop viable alternatives to conventional communication and sensing technologies. Most of the advanced driver-assist and autonomous vehicle technologies are based on Radio Detection and Ranging (RADAR) or Light Detection and Ranging (LiDAR) systems that use radio frequency or laser signals, respectively. While reliable and real-time information on vehicle speeds is critical for traffic operations management and autonomous vehicles safety, RADAR or LiDAR systems have some deficiencies especially in curved road scenarios where the incidence angle is rapidly varying. In this paper, we propose a novel speed estimation system so-called the Visible Light Detection and Ranging (ViLDAR) that builds upon sensing visible light variation of the vehicle's headlamp. We determine the accuracy of the proposed speed estimator in straight and curved road scenarios. We further present how the algorithm design parameters and the channel noise level affect the speed estimation accuracy. For wide incidence angles, the simulation results show that the ViLDAR outperforms RADAR/LiDAR systems in both straight and curved road scenarios. Publisher's Version

LiveBox: A Self-Adaptive Forensic-Ready Service for Drones

Scipedia content — Tue, 16 Feb 2021 10:02:18 +0100

eer-reviewed Unmanned Aerial Vehicles (UAVs), or drones, are increasingly expected to operate in spaces populated by humans while avoiding injury to people or damaging property. However, incidents and accidents can, and increasingly do, happen. Traditional investigations of aircraft incidents require on-board ight data recorders (FDRs); however, these physical FDRs only work if the drone can be recovered. A further complication is that physical FDRs are too heavy to mount on light drones, hence not suitable for forensic digital investigations of drone ights. In this paper, we propose a self-adaptive software architecture, LiveBox, to make drones both forensic-ready and regulation compliant. We studied the feasibility of using distributed technologies for implementing the LiveBox reference architecture. In particular, we found that updates and queries of drone ight data and constraints can be treated as transactions using decentralised ledger technology (DLT), rather than a generic time-series database, to satisfy forensic tamper-proof requirements. However, DLTs such as Ethereum, have limits on throughput (i.e. transactions-per-second), making it harder to achieve regulation-compliance at runtime. To overcome this limitation, we present a self-adaptive reporting algorithm to dynamically reduce the precision of ight data without sacri cing the accuracy of runtime veri cation. Using a real-life scenario of drone delivery, we show that our proposed algorithm achieves a 46% reduction in bandwidth without losing accuracy in satisfying both tamper-proof and regulation-compliant requirements.

A Functional Resonance Analysis Method Driven Resilience Quantification for Socio-Technical Systems

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

Due to the continuous increment in complexity of the socio-technical systems, decision makers call for new methods which are able to support timely as well as accurate decision-making related to resilience management. The current methods tend to be polarized on: efficiency-thoroughness forcing decision makers in making decisions on the base of resource availability instead of the problem to be solved. This paper presents a new fast-forward, cost-effective, and thorough enough framework to quantify resilience of a complex socio-technical system. The approach extends the functional resonance analysis method (FRAM) with a numerical method for the quantification of the analysis (Q-FRAM). In particular, it has been extended and operationalized the qualitative concepts of functional variability and dumping capacities into a method in which key performance indicators are derived from the model and aggregated into four indicators representing the FRAM resilience cornerstones (anticipate, respond, monitor, learn) through a bottom-up hierarchical approach. Finally, the four indicators are composed in a unique system resilience index that expresses the total variability present in the system at instant t . A numerical example of the use of the framework is provided together with a validation based on a comparison of the proposed approach with the current landscape.

The method of calculating emissions of pollutants from road transport in an urban environment

Scipedia content — Mon, 15 Feb 2021 12:30:29 +0100

To assess the quality of road traffic organization on environmental indicators, two methods of five regulations operating in the Russian Federation, which take into account the parameters of traffic flow, affecting the volume of emissions Pollutants. The parameter that affects the results of calculations in both methods is the average speed of movement. In real-world conditions on urban highways there are areas where the traffic flow is uneven (braking, acceleration, stopping), which entails an increase in the amount of pollutants from vehicles. At the same time, this uneven traffic is largely due to the existing the road design and traffic engineering on certain elements of the road network. This is the basis for the development of a methodology for calculating pollutant emissions to assess the quality of the traffic engineering, taking into account the uneven flow of traffic.

Document type: Article

Proposed OHTC Formula for Subsea Pipelines Considering Thermal Conductivities of Multi-Layered Soils

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

Subsea pipelines are designed to transport mixtures of oil, gas, and their associated impurities from a wellhead that can be in excess of approximately 100 °C, while the external temperature may be approximately 5 °C. Heat can be lost from a subsea pipeline containing a high-temperature fluid to the surrounding environment. It is important that the pipeline be designed to ensure that the heat loss is small enough to maintain sufficient flow from the unwanted deposition of hydrate and wax, which occurs at a critical temperature of about 40 °C. Therefore, it is essential to estimate the heat loss of a subsea pipeline in various circumstances. In previous studies, overall heat transfer coefficient(OHTC) formulas were considered only for a single soil type. Thus, it is difficult to characterize the OHTC of the actual seabed with multiple soil layers. In this paper, an OHTC formula that considers multi-layered soils is proposed for more precise OHTC estimation.

Document type: Article

Evaluating the Performance of Structure from Motion Pipelines

Scipedia content — Mon, 15 Feb 2021 12:28:59 +0100

Structure from Motion (SfM) is a pipeline that allows three-dimensional reconstruction starting from a collection of images. A typical SfM pipeline comprises different processing steps each of which tackles a different problem in the reconstruction pipeline. Each step can exploit different algorithms to solve the problem at hand and thus many different SfM pipelines can be built. How to choose the SfM pipeline best suited for a given task is an important question. In this paper we report a comparison of different state-of-the-art SfM pipelines in terms of their ability to reconstruct different scenes. We also propose an evaluation procedure that stresses the SfM pipelines using real dataset acquired with high-end devices as well as realistic synthetic dataset. To this end, we created a plug-in module for the Blender software to support the creation of synthetic datasets and the evaluation of the SfM pipeline. The use of synthetic data allows us to easily have arbitrarily large and diverse datasets with, in theory, infinitely precise ground truth. Our evaluation procedure considers both the reconstruction errors as well as the estimation errors of the camera poses used in the reconstruction.

Document type: Article

An Improved Deep Learning Model for Traffic Crash Prediction

Scipedia content — Mon, 15 Feb 2021 12:27:49 +0100

Machine-learning technology powers many aspects of modern society. Compared to the conventional machine learning techniques that were limited in processing natural data in the raw form, deep learning allows computational models to learn representations of data with multiple levels of abstraction. In this study, an improved deep learning model is proposed to explore the complex interactions among roadways, traffic, environmental elements, and traffic crashes. The proposed model includes two modules, an unsupervised feature learning module to identify functional network between the explanatory variables and the feature representations and a supervised fine tuning module to perform traffic crash prediction. To address the unobserved heterogeneity issues in the traffic crash prediction, a multivariate negative binomial (MVNB) model is embedding into the supervised fine tuning module as a regression layer. The proposed model was applied to the dataset that was collected from Knox County in Tennessee to validate the performances. The results indicate that the feature learning module identifies relational information between the explanatory variables and the feature representations, which reduces the dimensionality of the input and preserves the original information. The proposed model that includes the MVNB regression layer in the supervised fine tuning module can better account for differential distribution patterns in traffic crashes across injury severities and provides superior traffic crash predictions. The findings suggest that the proposed model is a superior alternative for traffic crash predictions and the average accuracy of the prediction that was measured by RMSD can be improved by 84.58% and 158.27% compared to the deep learning model without the regression layer and the SVM model, respectively.

Document type: Article

Power Quality Performance of Fast-Charging under Extreme Temperature Conditions

Scipedia content — Mon, 15 Feb 2021 12:23:12 +0100

Exposing electric vehicles (EV) to extreme temperatures limits its performance and charging. For the foreseen adoption of EVs, it is not only important to study the technology behind it, but also the environment it will be inserted into. In Europe, temperatures ranging from &minus

30 °

C to +40 °

C are frequently observed and the impacts on batteries are well-known. However, the impact on the grid due to the performance of fast-chargers, under such conditions, also requires analysis, as it impacts both on the infrastructure&rsquo

s dimensioning and design. In this study, six different fast-chargers were analysed while charging a full battery EV, under four temperature levels (&minus

25 °

C, &minus

15 °

C, +20 °

C, and +40 °

C). The current total harmonic distortion, power factor, standby power, and unbalance were registered. Results show that the current total harmonic distortion (THDI) tended to increase at lower temperatures. The standby consumption showed no trend, with results ranging from 210 VA to 1650 VA. Three out of six chargers lost interoperability at &minus

C. Such non-linear loads, present high harmonic distortion, and, hence, low power factor. The temperature at which the vehicle&rsquo

s battery charges is crucial to the current it withdraws, thereby, influencing the charger&rsquo

s performance.

Document type: Article

Feasibility study on fixed flight-path angle descent for wide-body passenger aircraft

Scipedia content — Mon, 15 Feb 2021 12:22:48 +0100

This study proposes the use of fixed flight-path angle (FPA) descent as a potential alternative for eco-friendly air traffic operations. Additionally, given that the proposed descent procedure follows a fixed, assigned flight-path angle, with the aircraft continuously descending toward the runway threshold with near-idle thrust, the trajectory should be more predictable for air-traffic controllers. As such, the proposed approach is expected to contribute significantly toward decreasing the air traffic fuel consumption, while simultaneously facilitating the air traffic controllers’ task of maintaining the required time spacing between concurrent traffic. Furthermore, FPA descent does not require any retrofits in the fundamental components of current ground systems and/or onboard avionics. This paper clarifies the feasibility of fixed flight-path angle descent for B777-200 and B787-8 wide-body jet passenger aircraft, envisaging its implementation in near-term operations. A total of 30 trials were carried out in a series of experiments designed to evaluate the proposed descent method, considering arrivals at two major international airports in Japan—the Tokyo and Kansai International Airports—using B777-200 and B787-800 full flight simulators of a national airline. The pilots’ procedures, cockpit operability, assigned vertical path tracking performance, and fuel efficiency associated with the proposed FPA descent are discussed and compared with those of conventional arrival operations. The analysis results indicate that the fixed flight-path angle descent is feasible for large-sized jet aircraft within the assumed operational environment, and that its combined use with speed control has the potential to result in even better energy-saving performance in future air traffic management operations.

Document type: Article

Exploring the integration of the power to gas technologies and the sustainable transport

Scipedia content — Mon, 15 Feb 2021 12:22:15 +0100

The de-carbonization of the transport sector is a particularly complex challenge as greenhouse gases are delocalized and diffused. Therefore, the problem has to be tackled from the source of the emissions, and efforts in the scientific and technological field must seek out new energy vectors of high density, neutral in CO2 and based on renewable energy that meet the sector demands and requisites. This could be the case of the synthetic natural gas which can be produced through the Power to Gas process (PtG). This process, originally developed by the German institutes ZSW and IWES, converts electricity into synthetic natural gas (SNG) via the methanation of CO2 together with H2 from water electrolysis. The energy content of the produced methane comes from the primary source for power generation (optimally renewable electricity) and it is possible to produce a CO2 neutral fuel by capturing the carbon emissions from an existing source. In addition, the PtG process can be seen as a new concept of renewable energy and CO2 hybrid storage. This paper identifies the possibilities that the Power to Gas technology offers for the production of sustainable methane and the existing potential for the symbiosis of industrial sectors through optimization of their waste streams of matter and energy. In particular power and transport sectors are considered and the outline of a small facility for the generation of synthetic natural gas from renewable electricity and its consumption in the vehicles of a road freight company is presented as a case study. Not only the technical feasibility but the economic viability of the process and the environmental improvements resulting from the use of a renewable fuel free of CO2 emissions in terms of carbon footprint are evaluated.

Document type: Article

Quantitative assessment of urban transport development – a spatial approach

Scipedia content — Mon, 15 Feb 2021 12:18:13 +0100

"jats:p"Urban transport is considered the basis of properly functioning cities and their development. The main aim of the paper is to attempt the assessment of urban transport development in selected voivodeships (provinces) as a crucial factor of macro logistics. The research also aimed to identify the underdeveloped areas of urban transport in Poland as the basis for the implementation of support policy. The source of information in the investigation process was data drawn from the Central Statistical Office in Poland for 2013–2016. In the scope of dealing with the research problem, chosen classical and order multivariate statistical measures were implemented into the research process. Next, the taxonomic measures for the years of interest served as the basis for the construction of the total (general) synthetic measure applicable to the entire period. The main results and findings of the research indicate that the level of urban transport development is correlated with the whole transportation system which affects the socio-economic development of some regions of Poland. The research can lead to a better understanding of Polish urban transportation development in selected regions. Hence, the results can be helpful in the investment process and for shaping the right transportation policy to improve the use of financial resources.

Document type: Article

Urban road traffic flow control under incidental congestion as a function of accident duration

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

"jats:p"An abrupt increase in urban road traffic flow caused by incidental congestion is considered. The residual traffic capacity varies in different lanes after an accident, and the influence of accident duration on traffic flow is taken into account. The swallowtail catastrophe model was built based on catastrophe theory. The critical state of traffic congestion under incidental congestion was analyzed using this model, and a traffic flow control scheme is proposed with the goal of maximizing the traffic capacity. Finally, the operational state of traffic flow under different scenarios is analyzed through case study and the feasibility of the model is validated.

Document type: Article

Dinoflagellates, a Unique Lineage for Retrogene Research

Scipedia content — Mon, 15 Feb 2021 12:16:00 +0100

The birth and evolution of retrogenes have played crucial roles in genome evolution. Dinoflagellates represent a unique lineage for retrogene research because the retrogenes can be reliably identified by the presence of a 22 nucleotide splice leader called DinoSL, which is post-transcriptionally added to the 5′ terminus of all mRNAs. Compared to studies of retrogenes conducted in other model genomes, dinoflagellate retrogenes can potentially be more comprehensively characterized because intron-containing retrogenes have already been detected. Unfortunately, dinoflagellate retrogene research has long been neglected. Here, we review the work on dinoflagellate retrogenes and show their distinct character. Like the dinoflagellate genome itself, dinoflagellate retrogenes are also characterized by many unusual features, including a high survival rate and large numbers in the genome. These data are critical complements to what we know about retrogenes, and will further frame our understanding of retroposition and its roles in genome evolution, as well as providing new insights into retrogene studies in other genomes.

Document type: Article

DIFTOS: A Distributed Infrastructure-Free Traffic Optimization System Based on Vehicular Ad Hoc Networks for Urban Environments

Scipedia content — Mon, 15 Feb 2021 12:15:14 +0100

Aiming to alleviate traffic congestion, many congestion avoidance and traffic optimization systems have been proposed recently. However, most of them suffer from three main problems. Firstly scalability: they rely on a centralized server, which has to perform intensive communication and computational tasks. Secondly unpredictability: they use smartphones and other sensors to detect the congested roads and warn upcoming vehicles accordingly. In other words, they are used to solve the problem rather than avoiding it. Lastly, infrastructure dependency: they assume the presence of pre-installed infrastructures such as roadside unit (RSU) or cellular 3G/4G networks. Motivated by the above-mentioned reasons, in this paper, we proposed a fully distributed and infrastructure-less congestion avoidance and traffic optimization system for VANET (Vehicular Ad-hoc Networks) in urban environments named DIFTOS (Distributed Infrastructure-Free Traffic Optimization System), in which the city map is divided into a hierarchy of servers. The vehicles that are located in the busy road intersections play the role of servers, thus DIFTOS does not rely on any centralized server and does not need internet connectivity or RSU or any kind of infrastructure. As far as we know, in the literature of congestion avoidance using VANET, DIFTOS is the first completely infrastructure-free congestion avoidance system. The effectiveness and scalability of DIFTOS have been proved by simulation under different traffic conditions.

Document type: Article

The Assessment of Mental Load of Air Traffic Controllers Based on Psychophysiological Indicators

Scipedia content — Mon, 15 Feb 2021 12:12:41 +0100

The article presents a part of a broader study on identifying and monitoring occupational risks, early detection of signs and symptoms of reversible impairment of physical and mental health of staff, decrease in work capacity and the occurrence of deficient, risky behavior in working practices, as a result of intense neuropsychological or physical professional effort. The results of the study aimed at highlighting: professional effort factors experienced by the trial subjects; occupational risk factors that cannot be avoided and which, due to the nature of the workload and the conditions for completing it, can in time lead to reduced work capacity, premature wear and tear, work-related illnesses and risky behaviors in the workplace, with serious consequences for the safety and health of employees and / or other people; measures to prevent and reduce identified work and stress factors, in order to ensure health and safety at work, optimal use of human resources and maintenance of work capacity throughout the professional life. The results can be implemented in the actions taken to ensure occupational health and safety regulations and to monitor employees’ health conditions and their work capacity in accordance with the legislation in force.

Document type: Article

Influence of unsteady pressure-flow conditions on strength of steel pipelines with volumetric defects reinforced by composite sleeves

Scipedia content — Mon, 15 Feb 2021 12:10:05 +0100

Structural integrity and risk management have a wide interest because of its practical applications, such as oil and gas pipelines, piping systems under pressure in power stations, urban water, and heating networks. The main goal of this paper is twofold. Firstly, to estimate the unsteady pressureflow variations in a gas transmission grid within the framework of sequential data assimilation. This technique enables to determine accurately the maximum pressure at the localized defect on the pipeline by merging measurements that contain random errors into the inexact numerical flow model. For this purpose, a particle filter is used. The semi-discretization approach is applied to convert the nonisothermal flow model into an initial value problem of ordinary differential equations. The spatial discretization is based on a five-point, fourth-order finite difference approximation and the time marching was done using a diagonally implicit Runge-Kutta scheme. Secondly, to study the strength of steel tubes reinforced with composite sleeves containing localized part-wall thickness losses caused by corrosion while taking into consideration a safe operating pressure. For a steel thin-walled cylinder containing a wrap of fiberglass with epoxy resin, the burst pressure and sleeve thickness are determined. Finally, the repaired pipeline with a fiber-reinforced composite sleeve is investigated. The results enable operators to handle problems of corroded steel pipelines and develop effective repair activities during operation. For this reason, current research is important for the maintenance of underground steel networks.

Document type: Article

Impact of Capacity Drop on Commuting Systems under Uncertainty

Scipedia content — Mon, 15 Feb 2021 12:09:16 +0100

This paper analyzes the impact of capacity drop on commuters’ travel choice behaviors under uncertainty. For clarity, we assume that the capacity drop is triggered by the queue forming at the bottleneck under the hypercongestion circumstances, and the stochasticity of the drop could not be neglected. Considering the uncertainty of travel time, we establish a bottleneck model with commuters choosing their departure time according to the mean travel cost. From the proposed model, analytical solutions are achieved and therefore several properties are presented, including monotonicity of travel cost and departure rate, and the relationship between dispersion degree and length of peak period. To alleviate traffic congestion at the bottleneck and avoid capacity drop, we design a time-varying toll scheme and a step toll scheme. Evolution of queue length in equilibrium is discussed based on the Laih model. Numerical examples are also presented to demonstrate the established model and the effectiveness of the proposed toll schemes.

Document type: Article

IMPROVING CAR NAVIGATION WITH A VISION-BASED SYSTEM

Scipedia content — Mon, 15 Feb 2021 12:08:11 +0100

The real-time acquisition of the accurate positions is very important for the proper operations of driver assistance systems or autonomous vehicles. Since the current systems mostly depend on a GPS and map-matching technique, they show poor and unreliable performance in blockage and weak areas of GPS signals. In this study, we propose a vision oriented car navigation method based on sensor fusion with a GPS and in-vehicle sensors. We employed a single photo resection process to derive the position and attitude of the camera and thus those of the car. This image georeferencing results are combined with other sensory data under the sensor fusion framework for more accurate estimation of the positions using an extended Kalman filter. The proposed system estimated the positions with an accuracy of 15 m although GPS signals are not available at all during the entire test drive of 15 minutes. The proposed vision based system can be effectively utilized for the low-cost but high-accurate and reliable navigation systems required for intelligent or autonomous vehicles.

Document type: Article

Influence of Soil Deformation Caused by Mining on Sewage Pipelines Built Using The Pipe Jacking Method

Scipedia content — Mon, 15 Feb 2021 12:06:50 +0100

This paper discusses the issues associated with the influence of underground mining operations on sewage pipelines built using the pipe jacking method. At present, to build sewage pipelines, especially in urban areas and deep embedment, trenchless technologies are employed. Mainly in these technologies, pipes are jacked into a bored tunnel using hydraulic jacks. These methods are also applied in mining areas."/jats:p""jats:p"The aim of this paper is to analyse the influence of ground deformation, caused by mining operations, on sewage pipelines built using the pipe jacking method. The type of pipelines discussed here is built with butted sections, which cannot compensate the influences of mining operations in pipe joints if horizontal compression occurs in the near-surface layer of soil. Pipelines embedded in trenches in the mining areas are secured against the influence of mining operations with expansion joints, which compensate for ground deformation. Hence, in the analysis of the influence of soil deformation caused by mining on sewage pipelines built using jacking method, special attention was paid to the performance of pipe joints. Pipelines of the type are subjected to additional loads and displacements, caused by soil deformations like horizontal strains, horizontal soil displacements and surface curvatures. We propose a way to consider the influence of mining operations on sewage pipelines built using the pipe jacking method.

Document type: Article

Analytical Model for Passing Sight Distance Design Criteria of Two-Lane Roads in Sri Lanka

Scipedia content — Mon, 15 Feb 2021 12:02:46 +0100

"jats:p"For a safe overtaking manoeuvre on two-lane highways, drivers need a sufficient sight distance along the roadway, but it depends on the traffic environment. To provide an adequate Passing Sight Distance (PSD), a number of models have been proposed since the initial model introduced by American Association of State Highways and Transport Officials (AASHTO) in 1954. It is a current design practice in Sri Lanka as well, however, not validated for local traffic conditions. This paper will present an alternative PSD model and an evaluation of AASHTO model for national highway design. Experiment was based on GPS data collection. In conclusion, PSD demand was satisfied by AASHTO PSD under mix traffic conditions, but not the safety concerns for speeds greater than 80 km/h, while alternative model successful for all speeds.

Document type: Article

Vibration and sound radiation of a rotating train wheel subject to a vertical harmonic wheel–rail force

Scipedia content — Mon, 15 Feb 2021 12:01:34 +0100

The rapid development of high-speed railway networks requires advanced methods for analysing vibration and sound radiation characteristics of a fast rotating train wheel subject to a vertical harmonic wheel–rail force. In order to consider the rotation of the wheel and at the same time increase the computational efficiency, a procedure is adapted in this paper taking advantage of the axial symmetry of the wheel. In this procedure, a recently developed 2.5D finite element method, which can consider wheel rotation but only requires a 2D mesh over a cross section containing the wheel axis, is used to calculate the vibration response of the wheel. Then, the vibration response of the wheel is taken as acoustic boundary condition and the 2.5D acoustic boundary element method, which only requires a 1D mesh over the boundary of the above cross section, is utilised to calculate the sound radiation of the wheel. These 2.5D methods and relevant programs are validated by comparing results from this procedure with those from conventional 3D analyses using commercial software. The comparison also demonstrates that these 2.5D methods have a much higher computational efficiency. Using the 2.5D methods, we study the wheel rotation speed influences on the factors including the vertical receptance of the wheel at wheel–rail contact point, sound pressure level at a pre-defined standard measurement point, radiated sound power level, directivity of the radiation, and contribution of each part of the wheel. It can be concluded that the wheel rotation speed splits most peaks of the vertical receptance at the wheel–rail contact point, sound pressure levels at the field, and the sound power level of the wheel into two peaks. The directivity and power contribution of the wheel are also significantly changed by the wheel rotation speed. Therefore, the rotation of a train wheel should be taken into account when calculating its vibration and sound radiation.

Document type: Article

Assessment of the scalability of a microtiter plate system for screening of oleaginous microorganisms

Scipedia content — Mon, 15 Feb 2021 11:59:40 +0100

Recent developments in molecular biology and metabolic engineering have resulted in a large increase in the number of strains that need to be tested, positioning high-throughput screening of microorganisms as an important step in bioprocess development. Scalability is crucial for performing reliable screening of microorganisms. Most of the scalability studies from microplate screening systems to controlled stirred-tank bioreactors have been performed so far with unicellular microorganisms. We have compared cultivation of industrially relevant oleaginous filamentous fungi and microalga in a Duetz-microtiter plate system to benchtop and pre-pilot bioreactors. Maximal glucose consumption rate, biomass concentration, lipid content of the biomass, biomass, and lipid yield values showed good scalability for Mucor circinelloides (less than 20% differences) and Mortierella alpina (less than 30% differences) filamentous fungi. Maximal glucose consumption and biomass production rates were identical for Crypthecodinium cohnii in microtiter plate and benchtop bioreactor. Most likely due to shear stress sensitivity of this microalga in stirred bioreactor, biomass concentration and lipid content of biomass were significantly higher in the microtiter plate system than in the benchtop bioreactor. Still, fermentation results obtained in the Duetz-microtiter plate system for Crypthecodinium cohnii are encouraging compared to what has been reported in literature. Good reproducibility (coefficient of variation less than 15% for biomass growth, glucose consumption, lipid content, and pH) were achieved in the Duetz-microtiter plate system for Mucor circinelloides and Crypthecodinium cohnii. Mortierella alpina cultivation reproducibility might be improved with inoculation optimization. In conclusion, we have presented suitability of the Duetz-microtiter plate system for the reproducible, scalable, and cost-efficient high-throughput screening of oleaginous microorganisms. Electronic supplementary material The online version of this article (10.1007/s00253-018-8920-x) contains supplementary material, which is available to authorized users.

Document type: Article

Comparative Study on the Applicability of Analytical and Experimental Methods in the Analysis of the Safe Use of Rail Tankers Carrying Petroleum Products Under Pressure

Scipedia content — Mon, 15 Feb 2021 11:58:27 +0100

"jats:p"The safety of railways has been and remains a critical topic. Whether it is infrastructure or rolling stock, the issue of safety is a permanent concern of the utmost importance, being reflected in the efficiency of any transport system."/jats:p" "jats:p"This paper focuses on the safety in operation of pressure vessels that equip railway tanks. There are many articles and works on this subject, and it is well-known that there are both national and international regulations regarding their design, execution, operation and maintenance. Also, there are quite a few reports on the BLEVE (Boiling Liquid Expanding Vapour Explosion) phenomenon resulting in material damage and significant casualties. The BLEVE-type explosion is not considered a chemical explosion derived from a gas-air explosive environment (also present in non-flammable gases), but rather a mechanical explosion through over-pressurization."/jats:p" "jats:p"Thus, we propose a comparative study between the results obtained using theoretical methods and those obtained as a result of tensoresistive measurements on such a tanker.

Document type: Article

Coordinated Control Model of Main-Signal and Pre-Signal for Intersections with Dynamic Waiting Lanes

Scipedia content — Mon, 15 Feb 2021 11:56:53 +0100

In order to alleviate the problem of the oversaturation of intersections, a traffic control method using a main-signal and pre-signals to periodically control the direction of dynamic waiting lanes was proposed in this paper. Based on the research on vehicle delay at intersections with dynamic waiting lanes and constraint relationships among a set of timing elements of the main-signal and pre-signal, a coordinated control model of a main-signal and pre-signal was built to minimize the average delay. Finally, a case study was performed to show that the proposed model is feasible. The objective optimization was performed by using a genetic algorithm to determine the main-signal and pre-signal timing scheme of the case study intersection, and then the average delay before and after installing dynamic waiting lanes was calculated and analyzed. The proposed method was found to be effective in reducing the intersection delay by 31.8% compared with the present situation of the intersection. Subsequently, the traffic volumes in the directions with dynamic waiting lanes installed were changed. It was demonstrated that with increasing traffic volumes, the effectiveness of the model to reduce intersection delay would be significant.

Document type: Article

A Nested Logit analysis of the influence of distraction on types of vehicle crashes

Scipedia content — Mon, 15 Feb 2021 11:56:03 +0100

Purpose This work aims to study factors, such as driver characteristics, environmental conditions, and vehicle characteristics, that affect different crash types with a special focus on distraction parameters. For this purpose, distraction factors are divided into five groups: cellphone usage, cognitive distractions, passengers distracting the driver, outside events attracting the driver’s attention, and in-vehicle activities. Methods Taking the crashes that occurred in the USA into account, the crash types are divided into two main groups, single-vehicle crashes and two-vehicle crashes. Since there were different crash types (alternatives) in the dataset and the probable correlation in the unobserved error term, the Nested Logit model is developed. Results The results of model illustrate that all of the aforementioned distraction-related factors increase the probability of run-off-road crashes, collision with a fixed object, and rear-end crashes. Cognitive distraction increases the probability of collision with a pedestrian. Distractions caused by passengers or out-of-vehicle events increase the probability of sideswipe crashes. Conclusion By examining how a factor affects multiple crash type outcomes, it is possible to devise countermeasures, improvements to roadway geometry, and traffic control strategies, while minimizing unintended consequences. The results should be of value in the design of educational programs and propose road safety improvement techniques.

Document type: Article

Indirect Damage of Urban Flooding: Investigation of Flood-Induced Traffic Congestion Using Dynamic Modeling

Scipedia content — Mon, 15 Feb 2021 11:55:10 +0100

In many countries, industrialization has led to rapid urbanization. Increased frequency of urban flooding is one consequence of the expansion of urban areas which can seriously affect the productivity and livelihoods of urban residents. Therefore, it is of vital importance to study the effects of rainfall and urban flooding on traffic congestion and driver behavior. In this study, a comprehensive method to analyze the influence of urban flooding on traffic congestion was developed. First, a flood simulation was conducted to predict the spatiotemporal distribution of flooding based on Storm Water Management Model (SWMM) and TELAMAC-2D. Second, an agent-based model (ABM) was used to simulate driver behavior during a period of urban flooding, and a car-following model was established. Finally, in order to study the mechanisms behind how urban flooding affects traffic congestion, the impact of flooding on urban traffic was investigated based on a case study of the urban area of Lishui, China, covering an area of 4.4 km"sup"2"/sup". It was found that for most events, two-hour rainfall has a certain impact on traffic congestion over a five-hour period, with the greatest impact during the hour following the cessation of the rain. Furthermore, the effects of rainfall with 10-and 20-year return periods were found to be similar and small, whereas the effects with a 50-year return period were obvious. Based on a combined analysis of hydrology and transportation, the proposed methods and conclusions could help to reduce traffic congestion during flood seasons, to facilitate early warning and risk management of urban flooding, and to assist users in making informed decisions regarding travel.

Document type: Article

A Comparison Analysis of Surrogate Safety Measures with Car-Following Perspectives for Advanced Driver Assistance System

Scipedia content — Mon, 15 Feb 2021 11:33:04 +0100

Surrogate Safety Measure (SSM) is one of the most widely used methods for identifying future threats, such as rear-end collision. Various SSMs have been proposed for the application of Advanced Driver Assistance Systems (ADAS), including Forward Collision Warning System (FCWS) and Emergency Braking System (EBS). The existing SSMs have been mainly used for assessing criticality of a certain traffic situation or detecting critical actions, such as severe braking maneuvers and jerking before an accident. The ADAS shows different warning signals or movements from drivers’ driving behaviours depending on the SSM employed in the system, which may lead to low reliability and low satisfaction. In order to explore the characteristics of existing SSMs in terms of human driving behaviours, this study analyzes collision risks estimated by three different SSMs, including Time-To-Collision (TTC), Stopping Headway Distance (SHD), and Deceleration-based Surrogate Safety Measure (DSSM), based on two different car-following theories, such as action point model and asymmetric driving behaviour model. The results show that the estimated collision risks of the TTC and SHD only partially match the pattern of human driving behaviour. Furthermore, the TTC and SHD overestimate the collision risk in deceleration process, particularly when the subject vehicle is faster than its preceding vehicle. On the other hand, the DSSM shows well-matched results to the pattern of the human driving behaviour. It well represents the collision risk even when the preceding vehicle moves faster than the follower one. Moreover, unlike other SSMs, the DSSM shows a balanced performance to estimate the collision risk in both deceleration and acceleration phase. These research findings suggest that the DSSM has a great potential to enhance the driver’s compliance to the ADAS, since it can reflect how the driver perceives the collision risks according to the driving behaviours in the car-following situation.

Document type: Article

Non-Roundabout design of cancel the intersection signal light on horizontal plane

Scipedia content — Mon, 15 Feb 2021 11:30:28 +0100

Traffic congestion is a world problem and an important factor restricting urban development. In order to solve the problem of urban traffic congestion, this paper takes the traffic flow theory and the intersection channel design theory as the research foundation, and conducts in-depth research on the causes of congestion at the intersection and the corresponding solutions, and proposes to cancel the traffic lights at the intersection without any stagnation. This paper proposes a new intersection design scheme, which is like the veins of the flower veins to channel the design intersection, cancel the signal light, and the vehicle can pass through the intersection without stagnation. It proposes a new solution to solve the traffic congestion problem. This new design allows the traffic flow to be spatially separated on the horizontal plane, and due to the cancellation of the signal lights, there is no signal waiting at the intersection, and the vehicle can travel without stopping at the intersection. At the same time, this paper also establishes a plane intersection service capability evaluation system based on simulation and quantitative calculation, which provides an evaluation index and proof basis for the non-stagnation driving channel design of the non-roundabout intersection.

Document type: Article

A macroscopic traffic model for traffic flow harmonization

Scipedia content — Mon, 15 Feb 2021 11:30:12 +0100

Traffic flow will harmonize to forward conditions. The time and distance required for harmonization can have a significant effect on the traffic density behavior. The flow can evolve into clusters of vehicles or become uniform depending on parameters such as safe time headway and safe distance headway. In this paper, a new model is presented to provide a realistic characterization of traffic behavior during the harmonization period. Results are presented for a discontinuous density distribution on a circular road which shows that this model produces more realistic traffic behavior than other models in the literature.

Document type: Article

Improving electric vehicle charging station efficiency through pricing

Scipedia content — Mon, 15 Feb 2021 11:28:15 +0100

Recent studies show that charging stations are operated in an inefficient way. Due to the fact that electric vehicle (EV) drivers charge while they park, they tend to keep the charging station occupied while not charging. This prevents others from having access. This study is the first to investigate the effect of a pricing strategy to increase the efficient use of electric vehicle charging stations. We used a stated preference survey among EV drivers to investigate the effect of a time-based fee to reduce idle time at a charging station. We tested the effect of such a fee under different scenarios and we modelled the heterogeneity among respondents using a latent class discrete choice model. We find that a fee can be very effective in increasing the efficiency at a charging station but the response to the fee varies among EV drivers depending on their current behaviour and the level of parking pressure they experience near their home. From these findings we draw implications for policy makers and charging point operators who aim to optimize the use of electric vehicle charging stations.

Document type: Article

DEVELOPMENT OF WEBGIS BASED REAL TIME ROAD TRAFFIC INFORMATION SYSTEM

Scipedia content — Mon, 15 Feb 2021 11:08:00 +0100

Abstract. Rapid increase in road traffic density results into a serious problem of Traffic Congestion (TC) in cities. During peaks hours TC is very high and hence public search least congested path for their journeys in order to minimize ravel time and hence transportation cost. In this study, a new empirical model was developed to estimate congestion levels using real time road Traffic Parameters (TPs) such as vehicle density, speed, class and vehicle-to-vehicle (V2V) gap. These real time road TPs were collected using latest generation Inductive Loop Detector (ILD) technology. Further, a WebGIS based Road Traffic Information System (RTIS) for Dehradun city was developed for real time TD analyses and visualisation. This RTIS is very useful for public and user departments for planning and decision making processes. No other such system is available in India, which handles multiple traffic parameters simultaneously to provide solution of day-to-day problems.

Document type: Article

The spatial–temporal dynamics in job accessibility by car in the Netherlands during the crisis

Scipedia content — Mon, 15 Feb 2021 11:07:07 +0100

This paper analyzes the changes in spatial–temporal job accessibility by car in the Netherlands during the economic crisis (2009–14). It also assesses which component change is the most determinant in accessibility changes per municipality and part of the day. The paper shows that changes in job distribution reduced accessibility in almost the entire country, except around Amsterdam. Improvements in the road network capacity increased accessibility in the central provinces, particularly during peak hours. In summary, the values of job accessibility by car in the Netherlands became more transport dependent, except in the Amsterdam region.

Document type: Article

Scaling Rules at Constant Frequency for Resonant Inductive Power Transfer Systems for Electric Vehicles

Scipedia content — Mon, 15 Feb 2021 11:02:13 +0100

The paper proposes the development of a set of rules for the resizing of inductive power transfer systems with particular attention to the ones dedicated to the charge of electric vehicles. These rules aim at the construction of down-scaled prototypes allowing the study and the design with benefits in terms of costs, time consumption and flexibility. The theoretical results are experimentally validated by comparing a 1.1 kW system with its down-scaled version.

Document type: Article

Is Uber a substitute or complement for public transit?

Scipedia content — Mon, 15 Feb 2021 10:59:03 +0100

How Uber affects public transit ridership is a relevant policy question facing cities worldwide. Theoretically, Uber’s effect on transit is ambiguous: while Uber is an alternative mode of travel, it can also increase the reach and flexibility of public transit’s fixed-route, fixed-schedule service. We estimate the effect of Uber on public transit ridership using a difference-in-differences design that exploits variation across U.S. metropolitan areas in both the intensity of Uber penetration and the timing of Uber entry. We find that Uber is a complement for the average transit agency, increasing ridership by five percent after two years. This average effect masks considerable heterogeneity, with Uber increasing ridership more in larger cities and for smaller transit agencies.

Document type: Article

Improving the efficiency of road transport companies by optimizing the costs of information and advertising activities

Scipedia content — Mon, 15 Feb 2021 10:56:25 +0100

In this article, we propose to improve the efficiency of transport companies by managing information and advertising activities to promote material flow. In this research, within the framework of planning the supply of consumer goods in cities, we offer the following alternative supply schemes: the direct goods delivery and delivery through distribution centres. In order to choose a rational supply scheme as a criterion of efficiency it was proposed to use the total delivery cost including the information and advertising component. The research also provides the methodology for determining the maximum effect of advertising activities by road transport companies. In addition, an example of developed advertising packages with the minimum and maximum advertising costs is given. The measures proposed in the research will allow developing a program to stimulate demand for transport services and increase the competitiveness of road transport companies in the transport market.

Document type: Article

An Improved Robust Principal Component Analysis Model for Anomalies Detection of Subway Passenger Flow

Scipedia content — Mon, 15 Feb 2021 10:52:15 +0100

Subway is an important transportation means for residents, since it is always on schedule. However, some temporal management policies or unpredicted events may change passenger flow and then affect passengers requirement for punctuality. Thus, detecting anomaly event, mining its propagation law, and revealing its potential impact are important and helpful for improving management strategy; e.g., subway emergency management can predict flow change under the condition of knowing specific policy and estimate traffic impact brought by some big events such as vocal concerts and ball games. In this paper, we propose a novel anomalies detection method of subway passenger flow. In this method, an improved robust principal component analysis model is presented to detect anomalies; then ST-DBSCAN algorithm is used to group the station-level anomaly data on space-time dimensions to reveal the propagation law and potential impact of different anomaly events. The real flow data of Beijing subway are used for experiments. The experimental results show that the proposed method is effective for detecting anomalies of subway passenger flow in practices.

Document type: Article

Hybrid Random Regret Minimization and Random Utility Maximization in the Context of Schedule-Based Urban Rail Transit Assignment

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

Route choice is one of the most critical passenger behaviors in public transit research. The utility maximization theory is generally used to model passengers’ route choice behavior in a public transit network in previous research. However, researchers have found that passenger behavior is far more complicated than a single utility maximization assumption. Some passengers tend to maximize their utility while others would minimize their regrets. In this paper, a schedule-based transit assignment model based on the hybrid of utility maximization and regret minimization is proposed to study the passenger route choice behavior in an urban rail transit network. Firstly, based on the smart card data, the space-time expanded network in an urban rail transit was constructed. Then, it adapts the utility maximization (RUM) and the regret minimization theory (RRM) to analyze and model the passenger route choice behavior independently. The utility values and the regret values are calculated with the utility and the regret functions. A transit assignment model is established based on a hybrid of the random utility maximization and the random regret minimization (RURM) with two kinds of hybrid rules, namely, attribute level hybrid and decision level hybrid. The models are solved by the method of successive algorithm. Finally, the hybrid assignment models are applied to Beijing urban rail transit network for validation. The result shows that RRM and RUM make no significant difference for OD pairs with only two alternative routes. For those with more than two alternative routes, the performance of RRM and RUM is different. RRM is slightly better than RUM in some of the OD pairs, while for the other OD pairs, the results are opposite. Moreover, it shows that the crowd would only influence the regret value of OD pair with more commuters. We conclude that compared with RUM and RRM, the hybrid model RURM is more general.

Document type: Article

Driver’s Lane Selection Model Based on Phase-Field Coupling and Multiplayer Dynamic Game with Incomplete Information

Scipedia content — Mon, 15 Feb 2021 10:50:00 +0100

Intelligent driving is an effective means to achieve the active safety of automobile, and the accurate prediction of vehicle group situation is the premise to achieve the intelligent driving of vehicle. Lane selection and lane changing are not only the most fundamental reasons for the transformation of vehicle group situation, but also the basic contents for the research on driver behavior of traffic flow theory. In this paper, with a view to the background of Internet of Things, the vehicle group situation was given a comprehensive consideration on the basis of the factors which influence driver’s behavior. The driver’s lane selection behavior was analyzed under the condition of incomplete information, and lane selection model based on phase-field coupling and multiplayer dynamic game with incomplete information was constructed considering the time-varying character of driving propensity. The means of actual driving experiment, virtual driving experiment, and microscopic simulation of traffic flow were used to verify the model. The verification results showed that the model built in this paper can objectively reflect the actual operation characteristic of traffic flow on road section and the process of lane selection. The theoretical basis of the research on lane selection can be provided for intelligent driving especially anthropomorphic driving under the condition of Internet of Things.

Document type: Article

Solving “Smart City” Transport Problems by Designing Carpooling Gamification Schemes with Multi-Agent Systems: The Case of the So-Called “Mordor of Warsaw”

Scipedia content — Mon, 15 Feb 2021 10:48:14 +0100

To reduce energy consumption and improve residents’ quality of life, “smart cities” should use not only modern technologies, but also the social innovations of the “Internet of Things” (IoT) era. This article attempts to solve transport problems in a smart city’s office district by utilizing gamification that incentivizes the carpooling system. The goal of the devised system is to significantly reduce the number of cars, and, consequently, to alleviate traffic jams, as well as to curb pollution and energy consumption. A representative sample of the statistical population of people working in one of the biggest office hubs in Poland (the so-called “Mordor of Warsaw”) was surveyed. The collected data were processed using spatial data mining methods, and the results were a set of parameters for the multi-agent system. This approach made it possible to run a series of simulations on a set of 100,000 agents and to select an effective gamification methodology that supports the carpooling process. The implementation of the proposed solutions (a “serious game” variation of urban games) would help to reduce the number of cars by several dozen percent, significantly reduce energy consumption, eliminate traffic jams, and increase the activity of the smart city residents.

Document type: Article

Improving of the monolithic foamconcrete quality for used in the high-rise constructions

Scipedia content — Mon, 15 Feb 2021 10:46:07 +0100

The article is devoted to the problem of obtaining the desired rheological characteristics of the foamconcrete when transporting it by the feeding pipelines to the place of installation in high-rise construction. The dependence of the density change of foamconcrete on the height to which it is transported is shown. It is stated that the use of stabilizers for the foam, as well as certain mechanisms of stabilization results in the concrete mix of the required density. To assess the rheological properties of the concrete mix the coefficient of volumetric relaxation is proposed.

Document type: Article

Stop Plan of Express and Local Train for Regional Rail Transit Line

Scipedia content — Mon, 15 Feb 2021 10:43:45 +0100

The urban rail transit line operating in the express and local train mode can solve the problem of disequilibrium passenger flow and space and meet the rapid arrival demand of long-distance passengers. In this paper, the Logit model is used to analyze the behavior of passengers choosing trains by considering the sensitivity of travel time and travel distance. Then, based on the composition of passenger travel time, an integer programming model for train stop scheme, aimed at minimizing the total passenger travel time, is proposed. Finally, combined with a certain regional rail line in Shenzhen, the plan is solved by genetic algorithm and evaluated through the time benefit, carrying capacity, and energy consumption efficiency. The simulation result shows that although the capacity is reduced by 6 trains, the optimized travel time per person is 10.34 min, and the energy consumption is saved by about 16%, which proves that the proposed model is efficient and feasible.

Document type: Article

The Air Cargo Carrying Potential of The Airbus A350-900XWB and Boeing 787-9 Aircraft on Their Ultra-Long-Haul Flights: A Case Study for Flights from San Francisco to Singapore

Scipedia content — Mon, 15 Feb 2021 10:42:43 +0100

"jats:p"The introduction of the Airbus A350-900 (A359) and the Boeing B787-9 (B789) have enabled airlines to operate ultra-long-range services. Using a mixed methods research design, this study has examined the air cargo-carrying potential of Singapore Airlines Airbus A350-900XWB (A359) and United Airlines Boeing B787-9 (789) aircraft on their ultra-long-haul San Francisco to Singapore and the Singapore to San Francisco air routes. The qualitative data was analysed using document analysis, and the air cargo payload was modelled by simulation. The air cargo-carrying potential of the two aircraft types was significantly influenced by enroute weather. In the event of eastbound winds, the Singapore Airlines Airbus A350-900XWB air cargo payload was 16.9 tonnes and the United Airlines Boeing 787-9 was 11.5 tonnes, when these flights had a full passenger payload. In the case of westbound winds with a full passenger payload, the Singapore Airlines Airbus A350-900XWB air cargo payload was 13.1 tonnes and the United Airlines Boeing 787-9 was 7.9 tonnes. When there were no winds on the air routes, the Singapore Airlines Airbus A350-900XWB offered 15.0 tonnes and the United Airline Boeing 787-9 offered 9.7 tonnes of air cargo payload, respectively.

Document type: Article

A New Three-Level Flying-Capacitor Boost Converter with an Integrated LC2D Output Network for Fuel-Cell Vehicles: Analysis and Design

Scipedia content — Mon, 15 Feb 2021 10:41:22 +0100

In this paper, a new three-level boost converter with continuous input current, common ground, reduced voltage stress on the power switches, and wide voltage gain range is proposed. The proposed converter is composed of a three-level flying-capacitor switching cell and an integrated LC2D output network. The LC2D output network enhances the voltage gain of the converter and reduces the voltage stress on the power switches. The proposed converter is a good candidate to interface fuel cells to the dc-link bus of the three-phase inverter of an electric vehicle (EV). A full steady-state analysis of the proposed converter in the continuous conduction mode (CCM) is given in this paper. A 1.2 kW scaled-down laboratory setup was built using gallium nitride (GaN) transistors and silicon carbide (SiC) diodes to verify the feasibility of the proposed converter.

Document type: Article

Towards Sophisticated Air Traffic Control System Using Formal Methods

Scipedia content — Mon, 15 Feb 2021 10:40:29 +0100

We propose a general formal modeling and verification of the air traffic control system (ATC). This study is based on the International Civil Aviation Organization (ICAO), Federal Aviation Administration (FAA), and National Aeronautics and Space Administration (NASA) standards and recommendations. It provides a sophisticated assistance system that helps in visualizing aircrafts and presents automatic bugs detection. In such a critical safety system, the use of robust formal methods that assure bugs absence is highly required. Therefore, this work suggests a formalism of discrete transition systems based on abstraction and refinement along proofs. These ensure the consistency of the system by means of invariants preservation and deadlock freedom. Hence, all invariants hold permanently providing a handy solution for bugs absence verification. It follows that the said deadlock freedom ensures a continuous running of a given system. This specification and modeling technique enable the system to be corrected by construction.

Document type: Article

Analog modeling of sand slope stability with different precipitation conditions

Scipedia content — Mon, 15 Feb 2021 10:39:45 +0100

Water–sand flow triggered by rainfall is the dominant mechanism for instability and failure of sand slopes. To further analyze the stability state of sand on a slope under different rainfall conditions, the initiation conditions and flow characteristics of water–sand flows are studied. Based on the theory of equilibrium forces and hydrological dynamics, a 1:100-scale analog model is built and verified with field observation data. The results indicate three dynamic stabilization stages of the sand slope under different weather conditions: dry sand, wet sand, and water–sand flow. Water–sand flows are triggered easily under short duration and heavy rainfall conditions. The rainfall threshold required to initiate water–sand flow is 4.14 mm/h. Rainfall amount and duration required to initiate water–sand flow decrease with fine sand content increasing. A sand head that develops at the front of the water–sand flow results in a flow along the edge of the sand debris flow and a “tree root” flow morphology. Modeling results are consistent with theoretical analysis and field observations.

Document type: Article

Are Brazilian cities ready to develop an efficient urban freight mobility plan?

Scipedia content — Mon, 15 Feb 2021 10:39:15 +0100

According to the Urban Mobility National Policy (UMNP), Brazilian cities with more than 20,000 inhabitants are obligated to elaborate Urban Mobility Plans (UMPs). The literature shows a lack of national research on urban freight planning and a need for better understanding issues on cargo transportation for authorities, especially regarding decision-making on policies and on urban freight transportation planning. City Logistics solutions can be considered on UMPs to reduce the problematic urban freight transport. Therefore, a survey was applied to investigate the resources available within cities to draw UMPs, the solutions for cargo movement in Brazilian cities, and the perceptions of public managers about freight transportation. The results show that “restrictions” are the solutions most adopted by Brazilian authorities, including the representative sample for cities within the São Paulo State with more than 250,000 inhabitants. The conclusions point out that Brazilian cities are not prepared to develop an efficient urban freight plan, as public managers seem to be unconscious about urban logistics demands within their cities or have neglected aspects regarding urban freight within the UMNP.

Resumo Conforme o Plano Nacional de Mobilidade Urbana (PNMU), as cidades brasileiras com mais de 20 mil habitantes são obrigadas a elaborar Planos de Mobilidade Urbana (PlanMob). A literatura mostra falta de pesquisas nacionais sobre planejamento e políticas de frete urbano e de um melhor entendimento para as autoridades sobre transporte de cargas, especialmente para a tomada de decisão sobre políticas e planejamento do transporte urbano de carga. Soluções para Logística Urbana podem ser consideradas nos PlanMobs para reduzir o problemático transporte urbano de cargas. Dessa forma, um levantamento de dados foi realizado para investigar os recursos disponíveis para as cidades planejarem o PlanMob, as soluções para a movimentação de cargas presentes nas cidades brasileiras e as percepções de gestores públicos sobre o transporte de carga em suas cidades. Os resultados mostram que as soluções mais adotadas pelas autoridades brasileiras são as restrições, incluindo uma amostra representativa das cidades do estado de São Paulo com mais de 250 mil habitantes. As conclusões apontam que as cidades brasileiras não estão preparadas para desenvolver um plano eficiente de transporte de carga urbano, porque os gestores públicos parecem estar inconscientes sobre demandas da logística urbana em suas cidades ou os gestores têm negligenciado aspectos de carga urbana dentro do PNMU.

Document type: Article

Application of AHP and DEMATEL Methods in Choosing and Analysing the Measures for the Distribution of Goods in Szczecin Region

Scipedia content — Mon, 15 Feb 2021 10:38:52 +0100

Urban areas are centres of business and innovation. Freight transport is indispensable for the proper functioning of any modern urban society. Urban areas cannot function without an appropriate freight transport system, due to the need to replenish stocks of food and other goods in retail shops. The complexity of the decisions concerning implementation of measures to improve the movement of goods in the city requires tools designed to support this process. In this context, a research gap and a research problem occur&mdash

how to obtain a reliable set of factors for development of sustainable urban freight transport (UFT). The purpose of this article is to introduce the possibility of applying the Analytic Hierarchy Process (AHP) as well as the Decision Making Trial and Evaluation Laboratory Method (DEMATEL) in choosing a set of measures and in analysing the field of distribution logistics, which will help to solve delivery problems and streamline cargo flow in Szczecin, in the context of sustainable development. This paper presents the findings of a survey in which experts evaluate the main coefficients for sustainable freight transport in the city area. Using both AHP and DEMATEL methods, we have concluded that: (i) all coefficients from administrative, financial, technical and promotional measures are highly interconnected

(ii) strategy of freight transport development should take into consideration how these coefficients influence each other

(iii) P2&mdash

eco-driving trainings, T4&mdash

alternative delivery systems and P1&mdash

promotional campaigns for sustainable transport are the most important criteria and should be priorities for investments

(iv) A1&mdash

implementation of loading/unloading and transit restrictions&mdash

highly influences other coefficients

(v) T2&mdash

intelligent route guidance in freight transport is greatly influenced by them.

Document type: Article

Near-term deployment of carbon capture and sequestration from biorefineries in the United States

Scipedia content — Mon, 15 Feb 2021 10:37:51 +0100

Significance Carbon dioxide removal through the permanent sequestration of biogenic CO2 is a critical technique for climate change mitigation, but most bioenergy with carbon capture and sequestration (CCS) technologies are technically immature or commercially unavailable. In contrast, examples of CCS of biogenic CO2 resulting from fermentation emissions already exist at scale. Here, we evaluate low-cost, commercially ready sequestration opportunities for existing biorefineries in the United States. We find that existing and proposed financial incentives suggest a substantial near-term opportunity to catalyze the growth of CCS infrastructure, improve the impacts of conventional biofuels, support development of carbon-negative biofuels, and satisfy low-carbon fuel policies.

Capture and permanent geologic sequestration of biogenic CO2 emissions may provide critical flexibility in ambitious climate change mitigation. However, most bioenergy with carbon capture and sequestration (BECCS) technologies are technically immature or commercially unavailable. Here, we evaluate low-cost, commercially ready CO2 capture opportunities for existing ethanol biorefineries in the United States. The analysis combines process engineering, spatial optimization, and lifecycle assessment to consider the technical, economic, and institutional feasibility of near-term carbon capture and sequestration (CCS). Our modeling framework evaluates least cost source–sink relationships and aggregation opportunities for pipeline transport, which can cost-effectively transport small CO2 volumes to suitable sequestration sites; 216 existing US biorefineries emit 45 Mt CO2 annually from fermentation, of which 60% could be captured and compressed for pipeline transport for under $25/tCO2. A sequestration credit, analogous to existing CCS tax credits, of $60/tCO2 could incent 30 Mt of sequestration and 6,900 km of pipeline infrastructure across the United States. Similarly, a carbon abatement credit, analogous to existing tradeable CO2 credits, of $90/tCO2 can incent 38 Mt of abatement. Aggregation of CO2 sources enables cost-effective long-distance pipeline transport to distant sequestration sites. Financial incentives under the low-carbon fuel standard in California and recent revisions to existing federal tax credits suggest a substantial near-term opportunity to permanently sequester biogenic CO2. This financial opportunity could catalyze the growth of carbon capture, transport, and sequestration; improve the lifecycle impacts of conventional biofuels; support development of carbon-negative fuels; and help fulfill the mandates of low-carbon fuel policies across the United States.

Document type: Article

Capacity Impacts and Optimal Geometry of Automated Cars’ Surface Parking Facilities

Scipedia content — Mon, 15 Feb 2021 10:34:16 +0100

The impact of Automated Vehicles (AVs) on urban geography has been widely speculated, though there is little quantitative evidence in the literature to establish the magnitude of such effects. To quantify the impact of the greater precision of automated driving on the spatial efficiency of off-street parking facilities, we develop a mixed integer nonlinear model (solved via a branch-and-cut approach) and present comparisons against industry-standard requirements for human-driving operation. We demonstrate that gains on the order of 40–50% in spatial efficiency (parking spaces per unit area) are in principle achievable while ensuring that each parked vehicle is independently accessible. We further show that the large majority of these efficiency gains can be obtained under current automotive engineering practice in which only the front two wheels pivot. There is a need for standardized methods that take the parking supply of a city as an input and calculate both the aggregate (citywide) efficiency impacts of automated driving and the spatial distribution of the effects. This study is intended as an initial step towards this objective.

Document type: Article

Analysis on Port and Maritime Transport System Researches

Scipedia content — Mon, 15 Feb 2021 10:26:06 +0100

This paper examines the past and current research in the container port and maritime field. Using rigorous bibliometric analysis, the paper identifies the core authors/affiliations, their rankings, and collaboration patterns. The analysis of the paper will enable new researchers to quickly build an understanding of the container port and maritime field by reading core authors’ papers published in specific journals.

Document type: Article

Accumulation of selected heavy metals in soils and common dandelion (Taraxacum officinale) near a road with high traffic intensity

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

"jats:p"The aim of the study was to determine the levels of selected trace elements in soils and in the common dandelion depending on the distance from a traffic route. The study was conducted in Warsaw near one of the main roads in the suburb of Ursynów. Samples for testing were taken from the 0–25 cm layer at sites located directly alongside the roadway and at a distance of 30, 60 and 300 m from its edge. The amounts of Pb, Ni, Cu, Zn and Cd in the soils were determined by the AAS method, after extraction in HCl at a concentration of 1 mol·dm"jats:sup"−3"/jats:sup", and in the aboveground parts and roots of dandelion plants after wet mineralization in a mixture of HNO"jats:sub"3"/jats:sub" and HClO"jats:sub"4"/jats:sub" by the AAS method. On the basis of the results obtained, it was shown that the concentrations of the tested metals, both in the soils and in the biomass of the test plant, were highest directly at the edge of the roadway and decreased significantly with the distance away from the road. This correlation indicates a significant impact of road transport on heavy metal levels in the environment bordering a traffic route. It was also shown that dandelion plants accumulate higher amounts of heavy metals in the aboveground parts than in the roots, and the heavy metal contents in the dandelion biomass were found to be significantly positively correlated with the amounts of these elements in the soils.

Document type: Article

Pedestrianism as an Effective Tool for Sustainable Intra-City Commuting in Calabar, Southern Nigeria

Scipedia content — Mon, 15 Feb 2021 10:23:40 +0100

"jats:p"The promotion of walking has become a global strategy in sustainable urban transportation planning. This is with the aim of reducing the urban commuter’s problems that result from the dominance of motorized urban transit, especially in developing countries with an increasing rate of urbanization. This study is carried out in Calabar, Southern Nigeria with the aim of assessing the conditions under which pedestrianism is enhanced. Research questionnaires were administered to household heads in all 22 localities with political delineation (wards) in the city. Respondents were sampled using the stratified sampling technique where every 10"jats:sup"th"/jats:sup" residential house is sampled after the initial listing of houses. Logistic regression analysis was conducted to predict the conditions under which about 382 household heads (about 98% respondent rate) in Calabar could undertake utilitarian walking using factors such as motorized traffic, weather conditions, lack of safety of pedestrians and socio-economic variables as category predictors. A test of the full model against a constant single model was statistically significant, indicating that the predictors, as a set, reliably distinguished utilitarian walking and non-walking (chi square = 60.544, p

Learning from Data to Predict Future Symptoms of Oncology Patients

Scipedia content — Mon, 15 Feb 2021 10:17:35 +0100

Effective symptom management is a critical component of cancer treatment. Computational tools that predict the course and severity of these symptoms have the potential to assist oncology clinicians to personalize the patient’s treatment regimen more efficiently and provide more aggressive and timely interventions. Three common and inter-related symptoms in cancer patients are depression, anxiety, and sleep disturbance. In this paper, we elaborate on the efficiency of Support Vector Regression (SVR) and Non-linear Canonical Correlation Analysis by Neural Networks (n-CCA) to predict the severity of the aforementioned symptoms between two different time points during a cycle of chemotherapy (CTX). Our results demonstrate that these two methods produced equivalent results for all three symptoms. These types of predictive models can be used to identify high risk patients, educate patients about their symptom experience, and improve the timing of pre-emptive and personalized symptom management interventions.

Document type: Article

A Uniform Strain Transfer Scheme for Accurate Distributed Optical Fiber Strain Measurements in Civil Structures

Scipedia content — Mon, 15 Feb 2021 10:16:38 +0100

We report a screw-like package design for an embeddable distributed optical fiber strain sensor for civil engineering applications. The screw-like structure is the exterior support for an optical fiber sensor. The bare optical fiber is embedded and secured in a longitudinal groove of the screw-like package using a rigid adhesive. Our packaging scheme prevents damage to the bare optical fiber and ensures that the packaged sensor is accurately and optimally sensing strain fields in civil structures. Moreover, our screw-like design has an equal area in a cross-section perpendicular to and along the screw axis, so strain field distributions are metered faithfully along the length of the embedded optical fiber. Our novel screw-like package optical fiber sensor, interfaced to a Rayleigh scattering-based optical frequency domain reflectometer system enables undistorted, accurate, robust, and spatially-distributed strain measurements in bridges, tunnels, pipelines, buildings, etc. along structural dimensions extending from centimeters to kilometers.

Document type: Article

From Antenna Design to High Fidelity, Full Physics Automotive Radar Sensor Corner Case Simulation

Scipedia content — Mon, 15 Feb 2021 10:16:21 +0100

Advanced driver assistance systems (ADAS) have recently been thrust into the spotlight in the automotive industry as carmakers and technology companies pursue effective active safety systems and fully autonomous vehicles. Various sensors such as lidar (light detection and ranging), radar (radio detection and ranging), ultrasonic, and optical cameras are employed to provide situational awareness to vehicles in a highly dynamic environment. Radar has emerged as a primary sensor technology for both active/passive safety and comfort-advanced driver-assistance systems. Physically building and testing radar systems to demonstrate reliability is an expensive and time-consuming process. Simulation emerges as the most practical solution to designing and testing radar systems. This paper provides a complete, full physics simulation workflow for automotive radar using finite element method and asymptotic ray tracing electromagnetic solvers. The design and optimization of both transmitter and receiver antennas is presented. Antenna interaction with vehicle bumper and fascia is also investigated. A full physics-based radar scene corner case is modelled to obtain high-fidelity range-Doppler maps. Finally, this paper investigates the effects of inclined roads on late pedestrian detection and the effects of construction metal plate radar returns on false target identification. Possible solutions are suggested and validated. Results from this study show how pedestrian radar returns can be increased by over 16 dB for early detection along with a 27 dB reduction in road construction plate radar returns to suppress false target identification. Both solutions to the above corner cases can potentially save pedestrian lives and prevent future accidents.

Document type: Article

Mathematical simulation of the rate of carbon dioxide corrosion at the facilities of Gazprom dobycha Urengoy LLC

Scipedia content — Mon, 15 Feb 2021 10:15:29 +0100

In Gazprom dobycha Urengoy LLC, as in other oil-and-gas production enterprises, there are problems of increased equipment wear due to corrosion. A special role there plays CO"jats:sub"2"/jats:sub" corrosion. Despite the homogeneity of the extracted fluid and even chemical composition of the working medium, the nature and intensity of corrosion damage to pipelines and equipment varies over a wide range, due to different thermobaric parameters of well operation. To determine parameters influencing the rate of corrosion most different methods of statistical analysis were used. The paper provides a methodology for compiling a mathematical model and assessing its reliability. As a result, the equation of carbon dioxide corrosion in relation to the conditions of Achimov deposits of Urengoy oil, gas and condensate field was obtained. The type of the obtained equation was chosen according to the model of the classical de Waard-Milliams carbon dioxide corrosion equation. The model proposed by the authors describes the processes of carbon dioxide corrosion more reliably than the de Waard-Milliams equation does. The disadvantage of the developed model is that it does not reliably describe the speed of corrosion in wells with corrosion rates, significantly exceeding the average values for all wells studied.

Document type: Article

Optimal Design of Transportation Networks with Automated Vehicle Links and Congestion Pricing

Scipedia content — Mon, 15 Feb 2021 10:15:03 +0100

We propose a bi-level network design model comprising automated vehicle (AV) links and congestion pricing to improve traffic congestion. As upper-level road planners strive to minimize total travel-time costs by optimizing both the network design and the congestion pricing, lower-level travelers make choices about their routes to minimize their individual travel costs. Our proposed model integrates a network design and congestion pricing to improve traffic congestion and we use a relaxation-based method to solve the model. We conducted a series of numerical tests to analyze the proposed model and solution method. Our results indicate that network design is more effective than congestion pricing when the AV market penetration is high and the opposite is true when AV penetration is low. More importantly, we find that a network design of automated vehicle links with congestion pricing is superior to a single network design or congestion pricing, especially when both AVs and conventional vehicles have a relatively large market penetration.

Document type: Article

Research on Hydraulic Characteristics in Diversion Pipelines under a Load Rejection Process of a PSH Station

Scipedia content — Mon, 15 Feb 2021 10:14:08 +0100

Transient analysis in diversion pipelines should be performed to ensure the safety of a hydropower system. After the establishment of a three-dimensional (3D) geometric model from the part upstream reservoir to the diversion pipeline end in a pumped storage hydropower (PSH) station, the hydraulic characteristics of the diversion system were solved by Reynold average Navier&ndash

Stokes (RANS) equations based on a volume of fluid (VOF) method under the condition of simultaneous load rejection of two units. The variations of the water level in the surge tank, the pressure at the pipeline end, and the velocity on the different pipeline sections with time were obtained through the calculation. The numerical results showed that the water level changing in the surge tank simulated by VOF was consistent with the field test data. These results also showed that a self-excited spiral flow occurs in the pipeline when the flow at the end of the pipeline was reduced to zero and its intensity decreased with the flow energy exhaustion. The discovery of the self-excited spiral flow in the study may provide a new explanation for the pressure wave attenuation mechanism.

Document type: Article

Context-Aware Intelligent Traffic Light Control through Secure Messaging

Scipedia content — Mon, 15 Feb 2021 10:12:47 +0100

In this paper, we propose STCM, a context-aware secure traffic control model to manage competing traffic flows at a given intersection by using secure messages with real-time traffic information. The vehicle is modeled as a virtual sensor which reports the traffic state, such as its speed and location, to a traffic light controller through a secure and computationally lightweight protocol. During the reporting process, a vehicle’s identity and location are kept anonymous to any other vehicle in the system. At an intersection, the traffic light controller receives the messages with traffic information, verifies the identities of the vehicles, and dynamically implements and optimizes the traffic light phases in real-time. Moreover, the system is able to detect the presence of emergency vehicles (such as ambulances and fire fighting trucks) in the communication range and prioritize the intersection crossing of such vehicles to in order to minimize their waiting times. The simulation results demonstrate that the system significantly reduces the waiting time of the vehicles in both light and heavy traffic flows compared to the pretimed signal control and the adaptive Webster’s method. Simulation results also yield effective robustness against impersonating attacks from malicious vehicles.

Document type: Article

Optimal Charging of Electric Vehicles with Trading on the Intraday Electricity Market

Scipedia content — Mon, 15 Feb 2021 10:09:43 +0100

Trading on the energy market is a possible way to reduce the electricity costs of charging electric vehicles at public charging stations. In many European countries, it is possible to trade electricity until shortly before the period of delivery on so called intraday electricity markets. In the present work, the potential for reducing the electricity costs by trading on the intraday market is investigated using the example of the German market. Based on simulations, the authors reveal that by optimizing the charging schedule together with the trading on the intraday electricity market, the costs can be reduced by around 8% compared to purchasing all the required energy from the energy supplier. By allowing the charging station operator to resell the energy to the intraday electricity market, an additional cost reduction of around 1% can be achieved. Besides the potential cost savings, the impacts of the trading unit and of the lead time of the intraday electricity market on the costs are investigated. The authors reveal that the achievable electricity costs can be strongly affected by the lead time, while the trading unit has only a minor effect on the costs.

Document type: Article

Turbine Blade of Gas Turbine Engine Additional Unloading by Changing the Layout of the Gravity Centre of the Shroud Shelf

Scipedia content — Mon, 15 Feb 2021 10:09:29 +0100

"jats:p"The article describes the impact of the gas turbine engine low-pressure turbine blade shroud shelf on the blade profile stress position. Attention is focused directly on the impact of the location of the gravity centre of the shroud shelf on blade stress distribution at the three most critical points of the profile. The paper describes the details of the calculation and the required expressions provided, as well as the results of the calculation example with clear graphical dependencies.

Document type: Article

Design, Analysis and Model Predictive Control of an Axial Field Switched-Flux Permanent Magnet Machine for Electric Vehicle/Hybrid Electric Vehicle Applications

Scipedia content — Mon, 15 Feb 2021 10:09:14 +0100

In this paper, an axial field switched-flux permanent magnet (AFSFPM) machine with stator-PM, which has a high power/torque density and efficiency feature as well as shorter axial length, is designed, analyzed and controlled. The topology, operating principle and design procedure of the AFSFPM machine are labored and discussed. The electromagnetic performance, including the flux linkage, back-EMF, cogging torque, winding inductance and field-control capability, are studied based on 3-D finite-element analysis (FEA). In order to investigate the operating performance of the machine in the whole speed range, a continuous-control-set model predictive control (MPC) method for the AFSFPM machine is proposed. Based on the stage control targets, the maximum torque per ampere (MTPA) and maximum output power flux-weakening strategies are presented in constant torque and constant power regions, respectively. Finally, a prototype of AFSFPM machine has been manufactured and experimentally evaluated and the results show that the MTPA strategy increases the load capability and the flux-weakening strategy broadens the constant power operation range. Moreover, the anti-load-disturbance capacity and dynamic response performance are improved under the MPC method. As a result, the proposed AFSFPM machine drive system is excellent alternative for electrical vehicles (EVs) or hybrid EVs (HEVs).

Document type: Article

Urban Transformation in the Context of Rail Transport Development: The Case of a Newly Built Railway Line in Gdańsk (Poland)

Scipedia content — Mon, 15 Feb 2021 10:07:14 +0100

Development of railway transport systems is perceived as one of the most effective ways of shaping sustainable urban transportation. However, railway transportation systems can only compete with individual means of transportation when having properly developed infrastructure, especially in terms of the train stops accessibility. The main objective of this article is to discuss mutual relations between operation of a newly built railway line and spatial changes taking place in its closest vicinity which determine the accessibility to it. The research methods included the GIS tools, direct measurements of passenger exchange, and public opinion poll among the passengers taking the new line. The research area was the city of Gdańsk, one of the largest cities in Poland, where transportation problems are cumulating as a result of the urban sprawl. The new railway was opened in order to mitigate these problems. The research results have proved this strategy was only partially successful as the course of the line and location of the stops do not provide a large number of potential passengers. That is why it was necessary to connect the line to the already existing urban transportation system, yet this solution has not resolved the problem completely. However, the urban development plan assumes introduction of large housing projects in the areas surrounding the existing train stops what will allow using the new line more efficiently in the future.

Document type: Article

Sustainability assessment of retail logistics solutions using external costs analysis: a case-study for the city of Antwerp

Scipedia content — Mon, 15 Feb 2021 10:06:22 +0100

Purpose Policy implementation in the logistics sector might drive unexpected side-effects which sometimes undermine the performance of key economic activities of logistics operators, especially in areas such as transport service, sustainability of operations, etc. Especially for the latter, there is a lack of understanding how the sustainability performance if retail logistics solutions is impacted on by policy implementation and, in turn, by operators’ responsive measures. This paper conducts a sustainability analysis of concrete innovative and already tested retail logistics solutions addressing the research question “what are the effects of retail logistics solutions on total costs and sustainability performance?” Methods The analysis relies on the development and application of an indicator-based framework based on the key sustainability components (economy, environment, society) and enriched by the addition of the transport component. The framework assesses three different scenarios together with a business-as-is one: Urban Consolidation Centre, Tethering and Shared Bus accompanied with a Strengths-Weaknesses analysis. Data are provided by an international food retailer operating within the city of Antwerp, Belgium, but conclusions can be generalized due to wider applicability of measures and solutions examined. Results External costs analysis shows that higher degree of internalization is achieved in the line-haul transport. Within an urban context, the measures that do not require significant initial investment and broad interventions are assessed as the most sustainable in our analysis. Tethering is the solution that indicates the highest sustainability score. Conclusions The impact of innovative and already tested solutions relies on a variety of factors: organizational, urban context, type of goods transported, engagement of stakeholders, etc.. In any case, innovation is crucial for urban retail logistics impacting on transport service, society, economy and environment. Any new retail business model should be designed with respect to cost efficiency and through a socially acceptable transition path.

Document type: Article

Complex Heat Pump Operational Mode Identification and Comparison for Use in Electric Vehicles

Scipedia content — Mon, 15 Feb 2021 09:58:30 +0100

Previous research has focused on the use of heat pumps in electric vehicles, with the focus on recuperating heat from, normally, ambient and one thermal source on the vehicle. Here 5 potential thermal sources on a vehicle have been identified and thorough testing on the benefit of each source has been performed. The results presented suggest the motor, a thermal storage device, and cabin exhaust extraction should be used >

80% of the time according to the scenarios tested, while battery heating and transmission heat extraction should be used subject to conditions on the ambient temperature and drive cycle.

Document type: Article

The role of landscape preferences in the travel decisions of railway passengers: Evidence from Hungary

Scipedia content — Mon, 15 Feb 2021 09:55:51 +0100

"jats:p"When surveying the motivation side of travel and tourism, we can state that tourists consider in their travel decisions, certain landscape preferences – to a certain extent. It also seems to be evident, however, that the objective evaluation of a landscape is a hard task for researchers for numerous reasons. In recent decades, several attempts have been made to create such methods but it seems that, in Hungary at least, this topic is rather neglected. The aim of this study is to provide an evaluation method for the landscape preferences of passengers travelling on Hungarian railway lines, demonstrating how the landscape around the railways could become an attraction during the travel. We survey what types of landscape appearance would be needed in order to generate travel decisions for tourists and also how the travel experience itself could become a tourism product.

Document type: Article