Scipedia: Documents published in 2018

Selecting an Appropriate Express Railway Pavement System Using VIKOR Multi-Criteria Decision Making Model

Scipedia content — Tue, 23 Mar 2021 05:05:38 +0100

A gigantic evolution has been brought about in the railway transportation by the emergence of the expressways as the most efficient method of carrying passengers within short and medium interurban distances. Various types of expressway pavements have been offered during the recent years. A considerable amount of the repair and maintenance costs in railroad sector is allocated to the constituents forming the pavements. No thorough and precise research has been so far conducted on the railroad expressways featuring traffics with speeds over 250 km/h and the extant information have merely been trivial changes in the procedures existent for speeds below 200 km/h and these are not deemed of much use and applicability. Thus, the current research paper is devoted to the investigation and selection of express railways pavement system design using VIKOR method. The evaluations indicate that the commencement of the first high-speed train work in 1964 in Japan marked a turning point in the railroad passenger transportation in the world. The development of the high-speed railway transportation is enumerated as an important revolution helping the railroads retake their crucial role in passenger transportation in such a way that it is found overtaking the roadway and aerial transportation and even exposing some airlines to real crisis. The high-speed railroad is undergoing an intensive expansion worldwide and as a safe, sound and sustainable transportation system, it has well proved its role in the social and economic development of the nations.

Document type: Article

Optimal Bus-Bridging Service under a Metro Station Disruption

Scipedia content — Tue, 23 Mar 2021 05:00:59 +0100

A station disruption is an abnormal operational situation that the entrance or exit gates of a metro station have to be closed for a certain of time due to an unexpected incident. The passengers’ travel behavioral responses to the alternative station disruption scenarios and the corresponding controlling strategies are complex and hard to capture. This can lead to the hardness of estimating the changes of the network-wide passenger demand, which is the basis of carrying out a response plan. This paper will establish a model to solve the metro station disruption problem by providing optimal additional bus-bridging services. Two main contributions are made: "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"""mml:mo stretchy="false""("/mml:mo""mml:mn fontstyle="italic""1"/mml:mn""mml:mo stretchy="false"")"/mml:mo""/mml:math" a three-layer discrete choice behavior model is developed to analyze the dynamic passenger flow demand under station disruption; and "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"""mml:mo stretchy="false""("/mml:mo""mml:mn fontstyle="italic""2"/mml:mn""mml:mo stretchy="false"")"/mml:mo""/mml:math" an integrated algorithm is designed to manage and control the station disruption crisis by providing additional bus-bridging services with the objective of minimizing the total travel time of affected passengers and the operating cost of bridging-buses. Besides, the multimodal transport modes, including metro, bridging-bus, shared-bike, and taxi, are considered as passengers’ alternative choices in face of the station disruption. A numerical study based on the Beijing metro network shows that additional bus-bridging services can significantly eliminate the negative impact of the station disruption.

Document type: Article

Rail Transit Development of the Pearl River Delta Planning, Obstacles and History

Scipedia content — Tue, 23 Mar 2021 04:52:15 +0100

A new round of regional planning was conducted from 2014 to 2016 by the provincial government of Guangdong, providing an overview of the regional transportation development and history. Major problems in the Pearl River Delta (PRD) railway network are identified: the inconsistencies between railway planning and land use, lack of transit-oriented regional policy, issues regarding the competition and compatibility of different methods of transportation by rail. This paper incorporates the following solutions which include direct connection of major regional business centers, improve railway and land use synergy, integrate railway and underground subway system and also discusses the future of railway transportation in densely populated areas.

Document type: Article

Modelling of runway excursions using Bayesian belief networks

Scipedia content — Tue, 23 Mar 2021 04:27:46 +0100

Runway excursion (RE) is recognized as one of the main Airport Safety Issues. It can be defined as an event in which an aircraft veers-off or overruns the runway surface during either takeoff or landing. In this paper an application of Bayesian Belief Network (BBN) method on RE events is presented. BBN belongs to quantitative class of causal methods. It estimates the risk of incident or accident according to estimation of probability of occurrence of each cause of an event. It might be restricted to pure statistical analysis based on the available data or combine these data with expert judgment (personal beliefs) on the accident causes. The aim of this paper is to identify potential causal factors, analyze and determine the probability of their realization. In order to illustrate BBN application on RE, two models were developed: one for landing and other for take-off. Based on the Ishikawa diagram method, causal factors have been identified, and then through a qualitative BBN model, their interdependencies are presented. The quantification of the model is accomplished by combining statistical data with the expert beliefs. Sensitivity analysis has shown what are the most critical causal factors whose knowledge allows developing certain measures to reduce the risk of RE.

Document type: Article

Environmental safety of the gas distribution system

Scipedia content — Tue, 23 Mar 2021 04:11:54 +0100

This article analyzes the causes of accidents on overhead gas pipelines. Special attention is paid to the operating conditions of gas distribution and gas consumption systems. The main measures aimed at reducing the environmental danger of gas supply systems operation have been identified. The main methods of increasing the reliability of gas distribution systems in the design of gas networks are considered. The complex index of reliability of gas distribution systems is used, which allows choosing the optimal version of the gas supply system.

Document type: Article

PiGx: reproducible genomics analysis pipelines with GNU Guix

Scipedia content — Tue, 23 Mar 2021 04:02:40 +0100

In bioinformatics, as well as other computationally intensive research fields, there is a need for workflows that can reliably produce consistent output, from known sources, independent of the software environment or configuration settings of the machine on which they are executed. Indeed, this is essential for controlled comparison between different observations and for the wider dissemination of workflows. However, providing this type of reproducibility and traceability is often complicated by the need to accommodate the myriad dependencies included in a larger body of software, each of which generally comes in various versions. Moreover, in many fields (bioinformatics being a prime example), these versions are subject to continual change due to rapidly evolving technologies, further complicating problems related to reproducibility. Here, we propose a principled approach for building analysis pipelines and managing their dependencies with GNU Guix. As a case study to demonstrate the utility of our approach, we present a set of highly reproducible pipelines called PiGx for the analysis of RNA sequencing, chromatin immunoprecipitation sequencing, bisulfite-treated DNA sequencing, and single-cell resolution RNA sequencing. All pipelines process raw experimental data and generate reports containing publication-ready plots and figures, with interactive report elements and standard observables. Users may install these highly reproducible packages and apply them to their own datasets without any special computational expertise beyond the use of the command line. We hope such a toolkit will provide immediate benefit to laboratory workers wishing to process their own datasets or bioinformaticians seeking to automate all, or parts of, their analyses. In the long term, we hope our approach to reproducibility will serve as a blueprint for reproducible workflows in other areas. Our pipelines, along with their corresponding documentation and sample reports, are available at http://bioinformatics.mdc-berlin.de/pigx

Document type: Article

A Global Sensitivity Analysis of Dynamic Loading and Route Selection Parameters on Network Performances

Scipedia content — Tue, 23 Mar 2021 03:36:36 +0100

We conduct a Global Sensitivity Analysis (GSA) of urban-scale network performances to parameters representing a wide range of realistic dynamic loadings, decomposed in a choice of OD matrix, routing alternatives, and paths flow distribution. A special attention is given to the route alternatives generation, where overlapping metrics and selection methods are introduced to reproduce a wide variety of paths sets configuration. Paths flow distributions are calculated based on different equilibrium criteria. Several sets of simulations are conducted and analyzed graphically and then with a variance-based GSA method so as to get insights on how much and in which conditions each network loading parameter influences network performances by itself or by interaction. Results notably reveal that the demand level is the most decisive parameter since low values simply lead to free-flow conditions with no influence of the other parameters, whereas higher values lead to a wide diversity of network states going from close to capacity but stable to gridlocked. While a nonnegligible amount of this disparity is explained by the demand pattern parameter, the number of paths per OD, their overlapping, and the equilibrium criterion of the paths flow distribution are still influential enough to maintain the network close to its optimal capacity or to prevent the network from fast collapse (gridlock). The highlighted connection between spatial and temporal heterogeneities of the network states explains the gridlocking phenomena. These extracted insights are very encouraging for operational implementations.

Document type: Article

Autonomous vehicles and freight traffic: towards better efficiency of road, rail or urban logistics?

Scipedia content — Tue, 23 Mar 2021 02:55:34 +0100

"jats:p"The freight transport sector is a low profit and high competition business and therefore has less ability to invest in research and development in the field of autonomous vehicles (AV) than the private car industry. There are already different levels of automation technologies in the transport industry, but most of these are serving niche demands and answers have yet to be found about whether it would be worthwhile to industrialise these technologies. New innovations from different fields are constantly changing the freight traffic industry but these are less disruptive than on other markets. The aim of this article is to show the current state of development of freight traffic with regards to AVs and analyse which future directions of development might be viable. The level of automation is very different in the case of different transport modes and most probably the technology will favour road transport over other, less environmentally harmful traffic modes.

Document type: Article

Experimental Observation on Variation of Rheological Properties during Concrete Pumping

Scipedia content — Tue, 23 Mar 2021 02:53:40 +0100

Workability of concrete varies during pumping. Even though concrete satisfies the required workability before pumping, it often does not satisfy the required standard after pumping. Moreover, serious problem could happen such as segregation and blockage. In this study, the rheological properties of concrete change during pumping from the pressure distribution over the pipe length was investigated. The rheological properties and the pressures measured from seven different real-scale pumping tests with 116 m to 1000 m long pipelines and 24 MPa to 100 MPa concrete were analyzed. As a result, it was found that the rheological properties vary gradually along the pipeline, and could abruptly change inside the pump. The variation of rheological properties during pumping seems to be attributed in part to the increase of water absorption in aggregates under high pressure and the additional mixing effect, namely, intensive shearing under high pressure inside pump.

Document type: Article

Numerical study of electro-osmotic consolidation effect on pipe-soil interaction

Scipedia content — Tue, 23 Mar 2021 02:51:26 +0100

Subsea pipelines are laid directly on seabed with further constraining measures to stabilise it against adverse effect of axial walking, upheaval buckling and lateral buckling. Costly mitigating measures are being employed and the need for further investigation to explore more option is considered. Stability of soil depends on the soil strength. Increasing the soil strength has been identified as a possible mitigation against pipeline displacement. Electro-osmotic consolidation process is currently being employed to increase soil strength around offshore and onshore structures, but the effect on pipe-soil interaction has not been fully investigated. This aspect received no attention on numerical model or detail experiment in this regard. The present study numerically investigates the effect of pipe-soil interaction using capabilities of commercial ABAQUS finite element software tool on both Electro-Kinetic (EK) treated and untreated soil to determine their behaviours. Results from this study when compared with non-EK treated soil, indicates remarkable developments, as the force required to displace pipeline increases significantly due to EK treatment.

Document type: Article

Application of multinomial and ordinal logistic regression to model injury severity of truck crashes, using violation and crash data

Scipedia content — Tue, 23 Mar 2021 02:28:28 +0100

In 2016 alone, around 4000 people died in crashes involving trucks in the USA, with 21% of these fatalities involving only single-unit trucks. Much research has identified the underlying factors for truck crashes. However, few studies detected the factors unique to single and multiple crashes, and none have examined these underlying factors to severe truck crashes in conjunction with violation data. The current research assessed all of these factors using two approaches to improve truck safety. The first approach used ordinal logistic regression to investigate the contributory factors that increased the odds of severe single-truck and multiple-vehicle crashes, with involvement of at least one truck. The literature has indicated that past violations can be used to predict future violations and crashes. Therefore, the second approach used risky violations, related to truck crashes, to identify the contributory factors to the risky violations and truck crashes. Driver actions of failure to keep proper lane following too close and driving too fast for conditions accounted for about 40% of all the truck crashes. Therefore, the same violations as the aforementioned driver actions were included in the analysis. Based on ordinal logistic regression, the analysis for the first approach indicated that being under non-normal conditions at the time of crash, driving on dry-road condition and having a distraction in the cabin are some of the factors that increase the odds of severe single-truck crashes. On the other hand, speed compliance, alcohol involvement, and posted speed limits are some of the variables that impacted the severity of multiple-vehicle, truck-involved crashes. With the second approach, the violations related to risky driver actions, which were underlying causes of severe truck crashes, were identified and analysis was run to identify the groups at increased risk of truck-involved crashes. The results of violations indicated that being nonresident, driving off-peak hours, and driving on weekends could increase the risk of truck-involved crashes. This paper offers an insight into the capability of using violation data, in addition to crash data, in identification of possible countermeasures to reduce crash frequency.

Document type: Article

SEM application to the household travel survey on weekends versus weekdays: the case of Seoul, South Korea

Scipedia content — Tue, 23 Mar 2021 02:13:22 +0100

Purpose This study analyzes the relationship that land use has with weekend travel in comparison to weekday travel. Unlike previous studies, it uses the same sample for two models that are specified to test the relationship separately for weekday and weekend travel. Methods Structural equation modeling is employed to test the land use–travel relationship. A comparison is made using two mode-specific travel measures: trip frequency and travel time. Results On weekday travel, land use in Seoul tends to reduce automobile trips and to add transit and nonmotorized trips. This does not lead to a reduction in the total frequency of weekday trips. Instead, an overall reduction occurs in the frequency of weekend trips because the addition of transit and nonmotorized trips is less than the reduction of automobile trips. Conclusions The application of structural equation modeling to a Seoul household travel survey confirms the opposing role of land use in travel mode choices on weekdays versus weekends.

Document type: Article

Studying the Topology of Transportation Systems through Complex Networks: Handle with Care

Scipedia content — Tue, 23 Mar 2021 02:07:07 +0100

The introduction of complex network concepts in the study of transportation systems has supposed a paradigm shift and has allowed understanding different transport phenomena as the emergent result of the interactions between the elements composing them. In spite of several notable achievements, lurking pitfalls are undermining our understanding of the topological characteristics of transportation systems. In this study, we analyse four of the most common ones, specifically related to the assessment of the scale-freeness of networks, the interpretation and comparison of topological metrics, the definition of a node ranking, and the analysis of the resilience against random failures and targeted attacks. For each topic we present the problem from both a theoretical and operational perspective, for then reviewing how it has been tackled in the literature and finally proposing a set of solutions. We further use six real-world transportation networks as case studies and discuss the implications of these four pitfalls in their analysis. We present some future lines of work that are stemming from these pitfalls and that will allow a deeper understanding of transportation systems from a complex network perspective.

Document type: Article

The Roles of Car Following and Lane Changing Drivers’ Anticipations during Vehicle Inserting Process: A Structural Equation Model Approach

Scipedia content — Tue, 23 Mar 2021 01:57:40 +0100

Anticipating ability is a skill that drivers count on to handle risky tasks in the traffic. This paper explores how the drivers of lane changing vehicle and its immediately car follower anticipate surrounding vehicles’ movements and adjust their manoeuvers during vehicle inserting process. The drivers’ anticipating mechanisms are modelled in the framework of structural equation model and estimated from field data. Results show that the change of lane changing type or traffic signal affects the drivers’ anticipation. Increased vehicle speed impels subject driver to anticipate driving condition in further future, but the stimulus is lower than the one coming from the kinematic comparisons of subject vehicle and other vehicles. The drivers care more about the vehicles’ interactions with which they are personally involved than the one to which they are only onlookers. The drivers’ responses to the counterpart vehicle’s movements depend on the progress of vehicle insertion and their roles in vehicle interactions.

Document type: Article

The Dependence of the Optimal Size of a Wind Turbine Tower on Wind Profile in Height

Scipedia content — Tue, 23 Mar 2021 01:42:24 +0100

"jats:p"In this article the necessity of measuring wind at its different heights is discussed. The economical optimization of tower height is impossible without such measurement. In places where land is relatively flat, for example, in deserts or swamps, smaller wind turbines are more profitable, while in forest zones bigger turbines are more profitable. In both cases, to make a correct decision on the optimal tower height, it is very important to know exactly the wind profile law. Even for places where land is expensive, the measurement of the wind at different heights can influence the correct decision regarding the optimal size and number of needed turbines for getting the required power. For places with cheaper land, this dependence is even stronger. This analysis refutes a common misconception: “the bigger – the better”.

Document type: Article

Logistics management of the rail connections using graph theory: the case of a public transportation company on the example of Koleje Dolnośląskie S.A.

Scipedia content — Tue, 23 Mar 2021 01:23:13 +0100

"jats:p"The main purpose of the paper was the structural analysis of the connections network used by a railway carrier Koleje Dolnośląskie S.A. operating in southern Poland. The analysis used simulation methods. The analysis and simulation were based on graph theory, which is successfully used in analysing a wide variety of networks (social, biological, computer, virtual and transportation networks). The paper presents indicators which allow judging the analysed connections network according to an appropriate level of transport services. Simulation results allowed proposing some modifications for the improvement of the analysed connections network. The paper also demonstrates that graph theory and network simulations should be used as tools by transportation companies during the stage of planning a connections network.

Document type: Article

Traffic Engineering Analysis in the Preparation and Reconstruction of Urban Roads

Scipedia content — Tue, 23 Mar 2021 01:11:16 +0100

The contribution deals with issues of road administration in municipalities in terms of the requirements for engineering renovations of urban communications networks. The goal is to declare an end to the degradation of the quality and service of local roads in cities. The reason is the lack of funding. The engineering analysis should demonstrate the need to make an informed request for reconstruction of local roads in our towns and cities. The aim of this paper is to describe the processes that are related to specific engineering work but are closely linked to the performance of the preparation on both sides, i.e., the administration versus the design. Why do we passively observe the gradual destruction of the quality of our local roads in the cities? Before our eyes the road constructions of roadways crumble, on the other hand, the level of their transport service on them only presents us with traffic jams. How can you know the status of the background of our streets and their pavements in an urbanized area? A couple of technical studies oriented towards the advance of public transport, especially for Bratislava, the capital of Slovakia which were based on traffic modelling together with engineering designs were published (Borš et.al, 2017; Pomichal et.al, 2017; Koštial et.al, 2017; Schlosser and Schlosser, 2016; Schlosser and Orthová, 2016; Schlosser et.al, 2016; Schlosser et.al, 2017; Schlosser et.al, 2017). Some answers to the complexities of this issue are set out in this article.

Document type: Article

A Subjective Optimal Strategy for Transit Simulation Models

Scipedia content — Tue, 23 Mar 2021 01:01:33 +0100

A behavioural modelling framework with a dynamic travel strategy path choice approach is presented for unreliable multiservice transit networks. The modelling framework is especially suitable for dynamic run-oriented simulation models that use subjective strategy-based path choice models. After an analysis of the travel strategy approach in unreliable transit networks with the related hyperpaths, the search for the optimal strategy as a Markov decision problem solution is considered. The new modelling framework is then presented and applied to a real network. The paper concludes with an overview of the benefits of the new behavioural framework and outlines scope for further research.

Document type: Article

Policy Considerations for Zero-Emission Vehicle Infrastructure Incentives: Case Study in Canada

Scipedia content — Tue, 23 Mar 2021 00:57:44 +0100

Transportation accounts for more than 20% of the total Greenouse Gas (GHG) emissions in Canada. Switching from fossil fuels to more environmentally friendly energy sources and to Zero-Emission Vehicles (ZEVs) is a promising option for future transportation but well to wheel emission and charging/refuelling patterns must also be considered. This paper investigates the barriers to and opportunities for electric charging and hydrogen refueling infrastructure incentives in Ontario, Canada and estimates the number of Internal Combustion Engine Vehicles (ICEVs) that would be offset by infrastructure incentives. The paper also assesses the potential of electric and hybrid-electric powertrains to enable GHG reductions, explores the impact of the electricity supply mix for supporting zero-emission vehicles in different scenarios and studies the effect of the utility factor for PHEVs in Ontario. The authors compare the use of electric vehicle charging infrastructures and hydrogen refueling stations regarding overall GHG emission reductions for an infrastructure incentive funded by a 20-million-dollar government grant. The results suggest that this incentive can provide infrastructure that can offset around 9000 ICEVs vehicles using electricity charging infrastructure and 4000&ndash

8700 when using hydrogen refuelling stations. Having appropriate limitations and policy considerations for the potential 1.7 million electric-based vehicles that may be in use by 2024 in Ontario would result in 5&ndash

7 million tonne GHG avoidances in different scenarios, equivalent to the removal of 1&ndash

1.5 million ICEVs from the road.

Document type: Article

Case Study of Corlu, Turkey

Scipedia content — Tue, 23 Mar 2021 00:54:16 +0100

The traffic congestion, which has become one of the major problems of developed and developing countries, has led to a shift in the way public transport systems are viewed, and it has accelerated efforts to increase the efficiency of these systems. In recent studies, several approaches, in which both user and operator benefits are evaluated together in order to increase the demand for public transportation systems and to ensure the sustainability of these systems, are emphasized. In this study, a bilevel simulation/optimization model is developed to optimize service headways and departure times of first buses from the beginning of the routes in urban bus networks. At the upper level of the proposed model, a multiobjective function representing user and operator costs is evaluated using the metaheuristic harmony search (HS) optimization technique. The transit assignment problem, which represents the distribution of transit users over the routes, is handled at the lower level. In the proposed model, the transit assignment problem is solved by the timetable-based assignment approach with VISUM transport planning software. The timetable-based transit assignment is an approach in which the perception errors within the users' route choice are taken into consideration and the transfer wait times can be precisely calculated. The proposed model is applied to a real-life urban bus network of the Çorlu district (Tekirdaǧ, Turkey), and the effectiveness of the model on a medium-sized urban bus system has been demonstrated. The results show that the user and operator benefits can be simultaneously increased by adding an initial departure offset parameter to the problem. © 2018 Huseyin Ceylan and Tayfun Ozcan.

Document type: Article

Ant Colony Optimized Routing Strategy for Electric Vehicles

Scipedia content — Tue, 23 Mar 2021 00:52:33 +0100

Electric vehicles (EVs) have recently attracted increasing research interest, on account of environmental issues and diminishing fuel reserves. EVs are environmentally friendly but have a short driving range. EVs must utilize energy efficiently, because they travel with limited energy. Conventional vehicle routing methods are not suitable for EVs, as they do not take energy consumption into account. This study introduces an energy efficient routing method using ant colony optimization (ER-ACO) to maximize the energy efficiency. We simulated ER-ACO and compared it with other ACO techniques, including the conventional routing method and other approaches for EVs. As a result, the proposed model improved the energy efficiency in terms of both the average distance per kW and average energy consumption.

Document type: Article

Total Cost of Ownership Based Economic Analysis of Diesel, CNG and Electric Bus Concepts for the Public Transport in Istanbul City

Scipedia content — Tue, 23 Mar 2021 00:47:36 +0100

across the world, in Turkey, several studies have been carried out by local government to use sustainable and 100% zero-emission public transport following increased public awareness. Increasing greenhouse gas emissions (GHG) due to transportation systems in the world make it necessary to establish &ldquo

zero-emission sustainable transportation systems&rdquo

in Turkey. In this study, an economic analysis based on actual field data is presented for Istanbul Electricity, Tramway and Tunnel General Management (IETT) to seek the suitability of an electric bus concept for Istanbul conditions. For this purpose, a dynamic model based on the Total Cost of Ownership (TCO) from well to wheel has been proposed for the three groups of transportation, namely diesel, CNG (compressed natural gas) and electric buses. The data source used in the proposed approach is created by performing actual field performance tests for diesel, CNG and electric buses under real Istanbul road, time, and trip conditions. Afterwards, the Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period (PB) methods considering TCO values and updated unit prices are carried out for the investment versus profitability analyses to compare the different public bus concepts. The results show that the electric bus concept with a charging station depot achieving sustainable and zero-emission goals will be the driving force to advance the electric bus concept for Istanbul Public Transport.

Document type: Article

Potensi Pengembangan Rute di Bandar Udara Mutiara SIS Al Jufri-Palu

Scipedia content — Tue, 23 Mar 2021 00:37:27 +0100

The Development Potential of Air Transportation Routes at Mutiara SIS Al Jufri Airport Palu: The government policy in regulating the air transportation routes on a macro basis aims to open up regional isolation and develop the potential of those regions. Mutiara SIS Al Jufri Airport is one of the entrances to the movement of people and goods through air transport to Central Sulawesi Province. Along with the increasingly socio-economic development of Palu City and Central Sulawesi Province in general, the demand for movement of people and goods also increased, and with the economic improvement of society of Central Sulawesi Province, air transportation becomes the main choice. This study is intended to measure the potential for the development of aviation routes at Mutiara SIS Al Jufri Airport, based on the opinion of current users of air transport and air carrier services, and adapted to the Master Plan of the Airport and the Spatial Planning Document of Central Sulawesi Province, using multiple linier regression analysis method. The results of the survey to the airlines provide the information about the plan to open the Palu-Morowali flight route due to its potential demand for transportation of goods between those cities using ATR-72 type aircraft, where there are many production of mining and palm oil products in Morowali. However, from the analysis, if ATR-72 aircraftshould be operated then the runway capacity at Morowali Airport have to be developed since the current condition with runway length of 1,050 m is not sufficient to be landed by ATR-72 in which require a runway with minimum length of 1,600 m.
Kebijakan pemerintah tentang pengaturan rute penerbangan secara makro bertujuan untuk membuka isolasi daerah dan mengembangkan potensi yang dimiliki masing-masing daerah tersebut.Bandar Udara Mutiara SIS Al-Jufri adalah salah satu pintu masuk pergerakan orang dan barang melalui angkutan udara ke Provinsi Sulawesi Tengah.Seiring dengan semakin berkembangnya sosio-ekonomi Kota Palu dan Provinsi Sulawesi Tengah pada umumnya, maka demand pergerakan orang dan barang pun turutmeningkat, dan dengan kemajuan perekonomian masyarakat di Provinsi Sulawesi Tengah maka transportasi udara menjadi pilihan utama. Pengkajian ini ingin melihat bagaimana potensi pengembangan rute penerbangan di Bandar Udara Mutiara SIS AlJufri, berdasarkan opini pengguna jasa angkutan udara dan maskapai penerbangan yang saat ini beroperasi, serta disesuaikan dengan rencana induk bandar udara dan dokumen Tata Ruang Wilayah Propinsi Sulawesi Tengah, dengan menggunakan metode analisis regresi linier berganda. Hasil survei kepada maskapai penerbangan diperoleh informasi adanya rencana pembukaan rute penerbangan Palu-Morowali yang sangat berpotensi adanya permintaan kebutuhan angkutan dari Morowali menuju kota Palu untuk angkutan barang dengan menggunakan pesawat udara jenis ATR-72, dikarenakan daerah Morowali banyak terdapat produksi hasil tambang dan kelapa sawit. Namun dari hasil analisis jika ingin menggunakan pesawat ATR-72, maka kapasitas landas Pacu (runway) di Bandar Udara Morowali harus dikembangkan karena kondisi saat ini dengan panjang 1.050 m masih belum memungkinkan untuk didarati oleh pesawat ATR72 yang membutuhkan minimal panjang runway 1.600 m.

Document type: Article

Ship Noise Level Analysis Based on the International Regulations

Scipedia content — Tue, 23 Mar 2021 00:29:16 +0100

"jats:p"The target of analyse was to determine the exposure levels to the staff on the vessel and ensure adequate measures are in place to minimize the exposure when necessary. Noise levels through the vessel will be compared to the noise code detailed in section 2 of this report. The measurement data results obtained at this survey will be analysed against the codes, as shown below. In addition, the measurement result table has the readings from 2007 during sea trials at the shipyard, Brodogradilište d.o.o. – Split. The analyse is to measure the exposure levels, through the accommodation and machinery spaces to determine the risk to staff working in these areas as well as making recommendations that could reduce the exposure levels.

Document type: Article

Tools4MSP: an open source software package to support Maritime Spatial Planning

Scipedia content — Tue, 23 Mar 2021 00:24:21 +0100

This paper presents the Tools4MSP software package, a Python-based Free and Open Source Software (FOSS) for geospatial analysis in support of Maritime Spatial Planning (MSP) and marine environmental management. The suite was initially developed within the ADRIPLAN data portal, that has been recently upgraded into the Tools4MSP Geoplatform (data.tools4msp.eu), an integrated web platform that supports MSP through the application of different tools, e.g., collaborative geospatial modelling of cumulative effects assessment (CEA) and marine use conflict (MUC) analysis. The package can be used as stand-alone library or as collaborative webtool, providing user-friendly interfaces appropriate to decision-makers, regional authorities, academics and MSP stakeholders. An effective MSP-oriented integrated system of web-based software, users and services is proposed. It includes four components: the "jats:italic"Tools4MSP Geoplatform"/jats:italic" for interoperable and collaborative sharing of geospatial datasets and for MSP-oriented analysis, the "jats:italic"Tools4MSP package as stand-alone library"/jats:italic" for advanced geospatial and statistical analysis, the "jats:italic"desktop applications"/jats:italic" to simplify data curation and the "jats:italic"third party data repositories"/jats:italic" for multidisciplinary and multilevel geospatial datasets integration. The paper presents an application example of the Tools4MSP GeoNode plugin and an example of Tools4MSP stand-alone library for CEA in the Adriatic Sea. The Tools4MSP and the developed software have been released as FOSS under the GPL 3 license and are currently under further development.

Document type: Article

Virtuelle Realität für Radargeräte in Autos

Scipedia content — Tue, 23 Mar 2021 00:12:46 +0100

Car manufacturers spend quite a lot on the development of driver assistance systems and subsequently on autonomous driving functionality. To ensure the safety and reliability of these functions meet industrial standards it is necessary to verify and validate their functionality. While tests on the road are still the ultimate evidence of correct operation they are associated with huge efforts and risks. Therefore, they have to be complemented by other means like simulations and tests on specialised testbeds. For the latter the car’s sensors have to be stimulated in a way that they perceive a desired – but only virtual – environment. An important type of sensor in cars is the radar due to its various advantages. This article describes the development of a stimulator generating virtual radar targets in order to enable the testing of autonomous driving functions.

Document type: Article

Lane Endpoint Detection and Position Accuracy Evaluation for Sensor Fusion-Based Vehicle Localization on Highways

Scipedia content — Tue, 23 Mar 2021 00:04:09 +0100

Landmark-based vehicle localization is a key component of both autonomous driving and advanced driver assistance systems (ADAS). Previously used landmarks in highways such as lane markings lack information on longitudinal positions. To address this problem, lane endpoints can be used as landmarks. This paper proposes two essential components when using lane endpoints as landmarks: lane endpoint detection and its accuracy evaluation. First, it proposes a method to efficiently detect lane endpoints using a monocular forward-looking camera, which is the most widely installed perception sensor. Lane endpoints are detected with a small amount of computation based on the following steps: lane detection, lane endpoint candidate generation, and lane endpoint candidate verification. Second, it proposes a method to reliably measure the position accuracy of the lane endpoints detected from images taken while the camera is moving at high speed. A camera is installed with a mobile mapping system (MMS) in a vehicle, and the position accuracy of the lane endpoints detected by the camera is measured by comparing their positions with ground truths obtained by the MMS. In the experiment, the proposed methods were evaluated and compared with previous methods based on a dataset acquired while driving on 80 km of highway in both daytime and nighttime.

Document type: Article

Comparative study on shotcrete repair solutions of buried steel pipelines

Scipedia content — Mon, 22 Mar 2021 23:50:02 +0100

The research aims to optimize the rehabilitation works of steel buried pipes after their lifespan is reached. It is based on objective real situations met in the Romanian agricultural irrigation system. The study proposes an analytical approach to predict the behavior of the rehabilitated pipelines initially subjected to various corrosion rates, from low to high agressivity of the environment. Besides traditional lining with reinforced concrete, a new trend given by the relative modern structural repair mortars is considered. The time behavior of the shotcrete lining is estimated based on information given by the appropriate European norm. The results question the design philosophy, still not clarified in the field, and emphasize the superior performance of modern cementitious materials, both in terms of technical performance and economical efficiency. Future research perspectives are also underlined with regard to the new materials meeting sprayed concrete technology requirements, and design philosophy.

Document type: Article

TOD residents’ attitudes toward walking to transit station: a case study of transit-oriented developments (TODs) in Bangkok, Thailand

Scipedia content — Mon, 22 Mar 2021 23:42:47 +0100

The study aims to analyze the attitude toward walking to the stations of residents living within 1 km of transit stations, or they are called transit-oriented development (TOD) residents. They are highly expected to walk to transit station and use rail in their daily travel. In this research, 249 respondents are asked 10 questions on attitudes of walking to station. The analysis was conducted in two stages: factor analysis and structural equation model. As the current access mode of respondents, walkers are more likely to be low-income households. People using motorized mode are mostly from middle- to high-income, households the largest group of respondents. For walking acceptance, high-income group accepts distance and time shorter than other incomes. Low-income households can accept the longer walking distance but shorter time. Middle-income households are more likely to walk in shorter distance than lower-income households, but they tend to accept longer walking time than others. As for the analysis results, the feeling of walking among all respondents significantly influences the walking acceptance. The benefit of walking significantly influences walking acceptance only among middle-income households. The walking attitudes on convenience, safety, a sense of freedom, healthiness, and environmental friendliness highly affect respondents’ acceptable walking distance and time in TODs.

Document type: Article

A Load Transportation Nonlinear Control Strategy Using a Tilt-Rotor UAV

Scipedia content — Mon, 22 Mar 2021 23:37:13 +0100

This paper proposes a nonlinear control strategy to solve the trajectory tracking problem of a tilt-rotor Unmanned Aerial Vehicle (UAV) when transporting a suspended load. For the present study, the aim of the control system is to track a desired trajectory of the aircraft with load’s swing-free, even in the presence of external disturbances, parametric uncertainties, unmodeled dynamics, and noisy position measurements with lower sampling frequency than the controller. The whole system modeling is obtained through the Euler-Lagrange formulation considering the dynamics of the tilt-rotor UAV coupled to the suspended load. As for the nonlinear control strategy, an inner-loop control is designed based on input-output feedback linearization combined with the dynamic extension approach to stabilize the attitude and altitude of the UAV assuming nonlinearities, while an outer-loop control law is designed for guiding the aircraft with reduced load swing. The linearized dynamics are controlled using linear mixed "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"""mml:msub""mml:mrow""mml:mi mathvariant="script""H"/mml:mi""/mml:mrow""mml:mrow""mml:mn mathvariant="normal""2"/mml:mn""/mml:mrow""/mml:msub""mml:mo"/"/mml:mo""mml:msub""mml:mrow""mml:mi mathvariant="script""H"/mml:mi""/mml:mrow""mml:mrow""mml:mi mathvariant="normal""∞"/mml:mi""/mml:mrow""/mml:msub""/mml:math" controllers with pole placement constraints. The solution is compared to two simpler control systems: the first one considers the load as a disturbance to the system but does not avoid its swing; the second one is a previous academic result with a three-level cascade strategy. Finally, in order to deal with the problem of position estimation in presence of unknown disturbances and noisy measurements with low sampling frequency, a Linear Kalman Filter with Unknown Inputs is designed for estimating both the aircraft’s translational position and translational disturbances. Simulation results are carried out to corroborate the proposed control strategy.

Document type: Article

Challenges of Promoting Sustainable Mobility on University Campuses: The Case of Eastern Mediterranean University

Scipedia content — Mon, 22 Mar 2021 23:28:30 +0100

Universities have the extraordinary ability to generate awareness regarding all aspects of sustainability in communities. To be successful, they must first adopt and model sustainable concepts within their own campuses. Transportation is one of the most affective sectors on the level of sustainability on university campuses. In recent decades, numerous universities around the world have begun encouraging usage of active modes of transportation through various strategies. This research has a multi-faceted approach to researching proven strategies, sampling local conditions, and making context-driven recommendations. The literature review outlines the most effective strategies related to Transportation Demand Management (TDM) for promoting usage of active modes of transportation inside university campuses. After that, the condition of existing facilities and strategies as well as commuters&rsquo

propensities related to active modes of transportation in the Eastern Mediterranean University (EMU) campus are evaluated using both qualitative and quantitative methods. The results include a set of recommendations and a framework for administrating, implementing, and enhancing a sustainable transportation system thereby increasing the commuter&rsquo

s use of sustainable active modes of transportation to, from, and within the university campus.

Document type: Article

Analyzing urban traffic demand distribution and the correlation between traffic flow and the built environment based on detector data and POIs

Scipedia content — Mon, 22 Mar 2021 23:24:14 +0100

Purpose This paper aims to determine the urban traffic flow spatiotemporal characteristics and correlation with the built environment using SCATS (Sydney Coordinated Adaptive Traffic System) and POIs (Point of Interests) data of Shenyang, China. Methods A standard analysis framework based on these data is proposed in the paper. The study analyzes the traffic volume spatiotemporal distributions and built environment influence factors determined by the geographical detector. An improved gravity model using simple structural parameters (lanes number and road length) is proposed to estimate the traffic flows of day and peak hour scales for specific flow ranges. Results The results show that the peak hours of different intersections and roads are heterogeneous and reveal trip time flexibility. The correlation between peak hour flows and day flows is significant in the multidimensional analysis. Based on the investigation of lanes, more interesting conclusions are found. In this case, when the numbers of lanes of intersections and roads are more than 14 and 4 respectively, the lane resources are wasted to a great extent. There is also a certain correlation between these factors. Proposed gravity model establishes the connection between structure and function of urban roads. Conclusions Flexible work time and places will be effective methods to reduce traffic congestion. The day flows could be estimated via a traffic survey on peak hour flows, especially in developing cities. The traffic flow mainly concentrates in a relatively small part of city roads. The maximum service traffic volumes exhibit segmentation, we should reconsider the maximum optimal lanes number of intersections and roads under better performance and utilization rate of the network. The effect of lanes number on the service traffic volumes is found to be more significant compared with the other factors. Our conclusions will be helpful for policy-makers and sustainable urban planning.

Document type: Article

Comparison of Factors Affecting Crash Severities in Hit-and-Run and Non-Hit-and-Run Crashes

Scipedia content — Mon, 22 Mar 2021 23:16:24 +0100

A hit-and-run (HR) crash occurs when the driver of the offending vehicle flees the crash scene without reporting it or aiding the victims. The current study aimed at contributing to existing literatures by comparing factors which might affect the crash severity in HR and non-hit-and-run (NHR) crashes. The data was extracted from the police-reported crash data from September 2017 to August 2018 within the City of Chicago. Two multinomial logistic regression models were established for the HR and NHR crash data, respectively. The odds ratio (OR) of each variable was used to quantify the impact of this variable on the crash severity. In both models, the property damage only (PDO) crash was selected as the reference group, and the injury and fatal crash were chosen as the comparison group. When the injury crash was taken as the comparison group, it was found that 12 variables contributed to the crash severities in both HR and NHR model. The average percentage deviation of OR for these 12 variables was 34%, indicating that compared with property damage, HR crashes were 34% more likely to result in injuries than NHR crashes on average. When fatal crashes were chosen as the comparison group, 2 variables were found to be statistically significant in both the HR and the NHR model. The average percentage deviation of OR for these 2 variables was 127%, indicating that compared with property damage, HR crashes were 127% more likely to result in fatalities than NHR crashes on average.

Document type: Article

Employing Incremental Outlines for OpenStreetMap Data Updating

Scipedia content — Mon, 22 Mar 2021 23:12:09 +0100

The updating of changing information plays a significant role in ensuring the quality of OpenStreetMap, which is usually completed by mapping the whole changing objects with a high degree of uncertainty. The incremental object-based approach provides opportunities to reduce the unreliability of data, while challenges of data inaccuracy and redundancy remain. This paper provides an incremental outline-based approach for OpenStreetMap data updating to solve this issue. First, incremental outlines are delineated from the changed objects and distinguished through a spatial classification. Then, attribute information corresponding to incremental outlines is proposed to assist in describing the physical changes. Finally, through a geometric calculation based on both the spatial and attribute information, updating operations are constructed with a variety of rules to activate the data updating process. The proposed approach was verified by updating an area in the OpenStreetMap datasets. The result shows that the incremental outline-based updating approach can reduce both the time and storage costs compared to incremental objects and further improve data quality in the updating process.

Document type: Article

Stress and Deformation Analysis of Buried Gas Pipelines Subjected to Buoyancy in Liquefaction Zones

Scipedia content — Mon, 22 Mar 2021 22:40:58 +0100

Buried pipelines are the main means of long distance transportation of natural gas. These pipelines are in high risk crossing liquefaction areas due to large deformations and stresses that may exist in pipe induced by the buoyancy load. In this study, a systematic analytical and numerical analysis were performed to investigate the mechanical behavior of a buried gas pipeline subjected to buoyancy in liquefaction areas. Soil constraints on pipe were considered accurately in the proposed models through soil spring assumptions. Effects of axial forces on pipe&rsquo

s bending deformation were also considered via the governing equations for beam under bending and tension. Deformation compatibility condition was utilized to derive the axial forces in pipe. The accuracy of the proposed analytical model was validated by comparing its results with those derived by an established rigorous finite element model. In addition, parametric analysis was finally performed using the analytical model to study the influences of pipe diameter, pipe wall thickness, soil spring stiffness and width of liquefaction zone on pipe&rsquo

s mechanical responses. This study can be referenced in the strength analysis and performance based safety evaluation of buried gas pipelines crossing liquefaction areas.

Document type: Article

EsATAC: an easy-to-use systematic pipeline for ATAC-seq data analysis

Scipedia content — Mon, 22 Mar 2021 22:39:41 +0100

Summary ATAC-seq is rapidly emerging as one of the major experimental approaches to probe chromatin accessibility genome-wide. Here, we present ‘esATAC’, a highly integrated easy-to-use R/Bioconductor package, for systematic ATAC-seq data analysis. It covers essential steps for full analyzing procedure, including raw data processing, quality control and downstream statistical analysis such as peak calling, enrichment analysis and transcription factor footprinting. esATAC supports one command line execution for preset pipelines and provides flexible interfaces for building customized pipelines. Availability and implementation esATAC package is open source under the GPL-3.0 license. It is implemented in R and C++. Source code and binaries for Linux, MAC OS X and Windows are available through Bioconductor (https://www.bioconductor.org/packages/release/bioc/html/esATAC.html). Supplementary information Supplementary data are available at Bioinformatics online.

Document type: Article

Performance Comparison of Geobroadcast Strategies for Winding Roads

Scipedia content — Mon, 22 Mar 2021 22:33:55 +0100

Vehicle-to-X (V2X) communications allow real-time information sharing between vehicles and Roadside Units (RSUs). These kinds of technologies allow for the improvement of road safety and can be used in combination with other systems. Advanced Driver Assistance Systems (ADAS) are an example and can be used along with V2X communications to improve performance and enable Cooperative Systems. A key element of vehicular communications is that the information transmitted through the network is always linked to a GPS position related to origin and destination (GeoNetworking protocol) in order to adjust the data broadcast to the dynamic road environment needs. In this paper, we present the implementation and development of Institute for Automobile Research (INSIA) V2X communication modules that follow the European vehicular networking standards in a close curve in a winding road where poor visibility causes a risk to the safety of road users. The technology chosen to support these communications is ETSI ITS-G5, which has the capability to enable specific services that support GeoNetworking protocols, specifically the Geobroadcast (GBC) algorithm. These functionalities have been implemented and validated in a real environment in order to demonstrate the performance of the communication devices in real V2V (Vehicle-to-Vehicle) and V2I (Vehicle-to-Infrastructure) situations. GBC messages are also compared with two different configurations of emission area. A comparison with/without RSU modules in critical areas of the road with previous knowledge of the road cartography has also been made.

Document type: Article

Adjustable Robust Optimization Algorithm for Residential Microgrid Multi-Dispatch Strategy with Consideration of Wind Power and Electric Vehicles

Scipedia content — Mon, 22 Mar 2021 22:17:08 +0100

A prospect of increasing penetration of uncoordinated electric vehicles (EVs) together with intermittent renewable energy generation in microgrid systems has motivated us to explore an effective strategy for safe and economic operation of such distributed generation systems. This paper presents a robust economic dispatch strategy for grid-connected microgrids. Uncertainty from wind power and EV charging loads is modeled as an uncertain set of interval predictions. Considering the worst case scenario, the proposed strategy can help to regulate the EV charging behaviors, and distributed generation in order to reduce operation cost under practical constraints. To address the issue of over-conservatism of robust optimization, a dispatch interval coefficient is introduced to adjust the level of robustness with probabilistic bounds on constraints, which gradually improves the system's economic efficiency. In addition, in order to facilitate the decision-making strategies from an economic perspective, this paper explores the relationship between the volatility of uncertain parameters and the economy based on the theory of interval forecast. Numerical case studies demonstrate the feasibility and robustness of the proposed dispatch strategy.

Document type: Article

Study on Gasoline Vehicle Emission Inventory Considering Regional Differences in China

Scipedia content — Mon, 22 Mar 2021 21:59:57 +0100

Rapid growth of China’s urban road vehicles, in particular, the increase in the number of gasoline vehicles, leads to an increase in the traffic congestion and problems pertaining to air pollution. The establishment of the emission inventory of gasoline vehicles is influenced by several factors, like environmental characteristics, vehicle conditions, road conditions, and so on. In order to obtain gasoline vehicle emission inventory in accordance with the actual situation in different regions, this study proposed a method of establishing a list of gasoline vehicles with regional differences. Comprehensive consideration and evaluation of various factors that affect the vehicle emissions were carried out and the corresponding correction factors were obtained. According to the formula of comprehensive emission factor for Zibo city, the emission inventory of gasoline vehicle was established. This method can be effectively utilized to obtain the emission inventory of gasoline vehicles in different cities more accurately and provide theoretical support for control strategies of gasoline vehicle emissions.

Document type: Article

Does Urban Rail Transit Discourage People from Owning and Using Cars? Evidence from Beijing, China

Scipedia content — Mon, 22 Mar 2021 21:53:06 +0100

With the rapid urbanization and motorization, many cities are developing urban rail transit (URT) to reduce car dependence. This paper explores the URT effect on car ownership and use based on the home-based work tour data in Beijing, China. Considering the mediating effects of car ownership and travel distance simultaneously, we develop a structural equation model to examine the complex relationship among URT, car ownership, travel distance, and car use. The results indicate that URT plays an important role in reducing car dependence. Living within URT catchment areas by itself is not significantly associated with car ownership and use, but if the workplace is near a URT station, people are less likely to own and use cars. People who both live and work near URT station areas have lower probability of owning and using cars. Moreover, car ownership and travel distance mediate the relationship between URT and car use, and the mediating effect of car ownership is greater than travel distance. Our study verifies that URT does discourage people from owning and using cars, which may have important implications for developing cities to make response to the ongoing motorization.

Document type: Article

From mobility patterns to behavioural change: leveraging travel behaviour and personality profiles to nudge for sustainable transportation

Scipedia content — Mon, 22 Mar 2021 21:51:55 +0100

Rendering transport behaviours more sustainable is a pressing issue of our times. In this paper, we rely on the deep penetration of mobile phones in order to influence citizens’ behavior through data-driven mobility and persuasive profiles. Our proposed approach aims to nudge users on a personalized level in order to change their mobility behavior and make more sustainable choices. To achieve our goal, first we leverage pervasive mobile sensing to uncover users’ mobility patterns and use of transportation modes. Second, we construct users’ persuadability profiles by considering their personality and mobility behavior. With the use of the aforementioned information we generate personalized interventions that nudge users to adopt sustainable transportation habits. These interventions rely on persuasive technologies and are embedded in a route planning application for smartphones. A pilot study with 30 participants using the system for 6 weeks provided fairly positive evaluation results in terms of the acceptance of our approach and revealed instances of behavioural change.

Document type: Article

Level of Services (LOS) for Public Bus and Passenger’s Aspiration in Kerian District, Malaysia

Scipedia content — Mon, 22 Mar 2021 21:49:38 +0100

Public transportation facilitates the mobility of activities and goods from all sustainable development key dimensions. Over the past decades, more trips of public transportation move people towards a more sustainable future, by reducing congestion on the roads and increasing the efficiency of the road system. The research aims at analysing the passenger’s aspiration and perspective of sustainable public transport measure and evaluating Malaysian rural bus services, using the case study of Kerian District in the state of Perak. On-board intercept passenger survey and adoption of Geographical Information System (GIS) / Global Positioning System (GPS) were used to collect the primary data. The research suggested that whilst the services levels are less than those aspired by the passengers, there are many improvement areas to be prioritised in the near future.Keywords: Sustainable transportation; sustainable transport indicator; transport planning; sustainable transportation dimension; passenger’s aspiration.eISSN 2398-4279 © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.

Document type: Article

ATAC2GRN: optimized ATAC-seq and DNase1-seq pipelines for rapid and accurate genome regulatory network inference

Scipedia content — Mon, 22 Mar 2021 21:41:31 +0100

Background Chromatin accessibility profiling assays such as ATAC-seq and DNase1-seq offer the opportunity to rapidly characterize the regulatory state of the genome at a single nucleotide resolution. Optimization of molecular protocols has enabled the molecular biologist to produce next-generation sequencing libraries in several hours, leaving the analysis of sequencing data as the primary obstacle to wide-scale deployment of accessibility profiling assays. To address this obstacle we have developed an optimized and efficient pipeline for the analysis of ATAC-seq and DNase1-seq data. Results We executed a multi-dimensional grid-search on the NIH Biowulf supercomputing cluster to assess the impact of parameter selection on biological reproducibility and ChIP-seq recovery by analyzing 4560 pipeline configurations. Our analysis improved ChIP-seq recovery by 15% for ATAC-seq and 3% for DNase1-seq and determined that PCR duplicate removal improves biological reproducibility by 36% without significant costs in footprinting transcription factors. Our analyses of down sampled reads identified a point of diminishing returns for increased library sequencing depth, with 95% of the ChIP-seq data of a 200 million read footprinting library recovered by 160 million reads. Conclusions We present optimized ATAC-seq and DNase-seq pipelines in both Snakemake and bash formats as well as optimal sequencing depths for ATAC-seq and DNase-seq projects. The optimized ATAC-seq and DNase1-seq analysis pipelines, parameters, and ground-truth ChIP-seq datasets have been made available for deployment and future algorithmic profiling. Electronic supplementary material The online version of this article (10.1186/s12864-018-4943-z) contains supplementary material, which is available to authorized users.

Document type: Article

A Causal Model for Safety Assessment Purposes in Opening the Low-Altitude Urban Airspace of Chinese Pilot Cities

Scipedia content — Mon, 22 Mar 2021 21:39:22 +0100

China has been gradually relaxing its ban on the use of low-altitude airspace across the country. To guarantee the high reliability of air traffic management (ATM), conflict detection and conflict resolution (CDR) approaches are indispensable to maintain safe separation between neighbouring small fixed-wing aircraft. In this study, we analyse a temporal and spatial integrated strategy for safety assessment purposes in opening the low-altitude urban airspace of Chinese pilot cities. First, we present a detailed mathematical description of the proposed algorithms based on a spatial grid partitioning system (SGPS). For our system, a conflict detection (CD) algorithm is designed to determine if two trajectories pass through the same grid space within overlapping time windows. A conflict resolution (CR) algorithm integrates a proposed time scheduling-based technique (TST) and vertical change-based technique (VCT), which operate under predetermined basic principles. Then, based on our novel CDR algorithms, a causal model is constructed in graphical modelling and analysis software (GMAS) to generate a state space that can provide a global perspective on scenario dynamics and better understanding of induced conflict occurrences. Finally, simulation results demonstrate that the proposed approach is practical and efficient.

Document type: Article

A Capillary Computing Architecture for Dynamic Internet of Things: Orchestration of Microservices from Edge Devices to Fog and Cloud Providers

Scipedia content — Mon, 22 Mar 2021 21:33:56 +0100

The adoption of advanced Internet of Things (IoT) technologies has impressively improved in recent years by placing such services at the extreme Edge of the network. There are, however, specific Quality of Service (QoS) trade-offs that must be considered, particularly in situations when workloads vary over time or when IoT devices are dynamically changing their geographic position. This article proposes an innovative capillary computing architecture, which benefits from mainstream Fog and Cloud computing approaches and relies on a set of new services, including an Edge/Fog/Cloud Monitoring System and a Capillary Container Orchestrator. All necessary Microservices are implemented as Docker containers, and their orchestration is performed from the Edge computing nodes up to Fog and Cloud servers in the geographic vicinity of moving IoT devices. A car equipped with a Motorhome Artificial Intelligence Communication Hardware (MACH) system as an Edge node connected to several Fog and Cloud computing servers was used for testing. Compared to using a fixed centralized Cloud provider, the service response time provided by our proposed capillary computing architecture was almost four times faster according to the 99th percentile value along with a significantly smaller standard deviation, which represents a high QoS.

Document type: Article

Distribution-Free Model for Ambulance Location Problem with Ambiguous Demand

Scipedia content — Mon, 22 Mar 2021 21:17:36 +0100

Ambulance location problem is a key issue in Emergency Medical Service (EMS) system, which is to determine where to locate ambulances such that the emergency calls can be responded efficiently. Most related researches focus on deterministic problems or assume that the probability distribution of demand can be estimated. In practice, however, it is difficult to obtain perfect information on probability distribution. This paper investigates the ambulance location problem with partial demand information; i.e., only the mean and covariance matrix of the demands are known. The problem consists of determining base locations and the employment of ambulances, to minimize the total cost. A new distribution-free chance constrained model is proposed. Then two approximated mixed integer programming (MIP) formulations are developed to solve it. Finally, numerical experiments on benchmarks (Nickel et al., 2016) and 120 randomly generated instances are conducted, and computational results show that our proposed two formulations can ensure a high service level in a short time. Specifically, the second formulation takes less cost while guaranteeing an appropriate service level.

Document type: Article

Data and Cyber Security in Autonomous Vehicle Networks

Scipedia content — Mon, 22 Mar 2021 21:16:37 +0100

"jats:p"An autonomous vehicle (AV) is a vehicle that operates and performs tasks under its own power. Some features of autonomous vehicle are sensing the environment, collecting information and managing communication with other vehicles. Many autonomous vehicles in development use a combination of cameras, sensors, GPS, radar, LiDAR, and on-board computers. These technologies work together to map the vehicle’s position and its proximity to everything around it. Because of their reliance on these sorts of technologies, which are easily accessible to tampering, a autonomous vehicles are susceptible to cyber attacks if an attacker can discover a weakness in a certain type of vehicle or in a company’s electronic system. This lack of information security can lead to criminal and terrorist acts that eventually cost lives. This paper gives an overview of cyber attack scenarios relating to autonomous vehicles. The cyber security concept proposed here uses biometric data for message authentication and communication, and projects stored and new data based on iris recognition. Iris recognition system can provide other knowledge about drivers as well, such as how tired and sleepy they might be while driving, and they are designed to encrypt the vehicle-to-vehicle and vehicle-to-environment communication based on encryption security mechanisms.

Document type: Article

The Location Selection for Roundabout Construction Using Rough BWM-Rough WASPAS Approach Based on a New Rough Hamy Aggregator

Scipedia content — Mon, 22 Mar 2021 21:15:39 +0100

n adequately functionally located traffic infrastructure is an important factor in the mobility of people because it affects the quality of traffic, safety and efficiency of carrying out transportation activities. Locating a roundabout on an urban network is an imperative for road engineering to address traffic problems such as reduction of traffic congestion, enhancement of security and sustainability, etc. Therefore, this paper evaluates potential locations for roundabout construction using Rough BWM (Best Worst Method) and Rough WASPAS (Weighted Aggregated Sum Product Assessment) models. Determination of relative criterion weights on the basis of which the potential locations were evaluated was carried out using the Rough BWM method. In this paper, in order to enable the most precise consensus for group decision-making, a Rough Hamy aggregator has been developed. The main advantage of the Hamy mean (HM) operator is that it can capture the interrelationships among multi-input arguments and can provide DMs more options. Until now, there is no research based on HM operator for aggregating imprecise and uncertain information. The obtained indicators are described through eight alternatives. The results show that the fifth and sixth alternatives are the locations that should have a priority in the construction of roundabouts from the perspective of sustainable development, which is confirmed throughout changes of parameter k and with comparing to other methods in the sensitivity analysis.

This article belongs to the Special Issue Multi-Objective and Multi-Attribute Optimisation for Sustainable Development Decision Aiding

Document type: Article

An Earlier Predictive Rollover Index Designed for Bus Rollover Detection and Prevention

Scipedia content — Mon, 22 Mar 2021 21:14:27 +0100

As vehicle rollovers annually cause a great deal of traffic-related deaths, an increasing number of vehicles are being equipped with rollover prevention systems with the aim of avoiding such accidents. To improve the functionality of active rollover prevention systems, this study provided a potential enhanced method with the intention to predict the tendency of the lateral load transfer ratio (LTR), which is the most common rollover index. This will help provide a certain amount of lead time for the control system to respond more effectively. Before the prediction process, an estimation equation was proposed to better estimate the LTR; the equation was validated using Simulink and TruckSim. Further, to eliminate the influence of drawbacks and make this method practical, a buffer operator was added. Simulation results showed that grey LTR (GLTR) was able to roundly predict the future trend of the LTR based on current and previous data. Under the tests of “Sine with Dwell” (Sindwell) and double lane change (DLC), the GLTR could provide the control system with sufficient time beforehand. Additionally, to further examine the performance of the GLTR, a differential system model was adopted to verify its effectiveness. Through the Sindwell maneuver, it was demonstrated that the GLTR index could improve the performance of the rollover prevention systems by achieving the expected response.

Document type: Article

Road transport vehicles in South Africa towards 2050: Factors influencing technology choice and implications for fuel supply

Scipedia content — Mon, 22 Mar 2021 20:57:16 +0100

The South African transport sector is estimated to emit 60 MtCO2eq and require 800 PJ of energy, similar in scale to industrial energy demand and emissions. The sector is forecast to potentially eclipse industry in this regard if conventional vehicle choices and travel modes persist. This paper explores scenarios of transport technology choices and demand in a future of uncertain fuel and technology costs, and the consequences for energy supply and greenhouse gas emissions. It explores the extent of electric vehicle (EV) adoption and the implication of fuel migration from petroleum products. The preference for alternative fuels such as hydrogen, liquid biofuels and natural gas is also investigated. The evolution of road transport in South Africa towards 2050 is investigated utilising the South African TIMES model, a full energy sector least-cost optimisation model that relies on a rich technological database of the entire energy supply and demand system. Hydrogen fuel cell vehicles are shown to be a viable option in freight and public transport, potentially meeting 70% of travel demand by 2045. The private passenger and light commercial sectors emerge as the main market for electric vehicles, potentially accounting for 80% of new vehicle sales by 2045. Electricity as a transport fuel could account for 30% of fuel supply and reduce transport emissions to half of present day estimates. However, the key uncertainty driving EV adoption is future vehicle costs and crude oil prices, which could dampen EV uptake. Another main finding is that petroleum-dependent vehicles remain an important vehicle class, and that re-investment in existing crude oil refineries to conform to Euro5 standards is a likely requirement. There seems to be little indication, however, that additional refining capacity would be economically viable within the planning horizon.

Document type: Article

A Methodology for Choosing between Route Deviation and Point Deviation Policies for Flexible Transit Services

Scipedia content — Mon, 22 Mar 2021 20:51:37 +0100

Flexible transit services, which bring together the characteristics of fixed-route transit and demand-responsive transit, have been proven to be cost-efficient in low-density residential areas. In this paper, a methodology is proposed to assist planners in making better decisions when choosing between route deviation policy and point deviation policy, which are two promising types of flexible transit services. A user cost function is developed to measure the service quality of the transit systems, and analytical models are constructed to compare the system performance under both expected and unexpected demand levels. Based on the experiments for various scenarios over a real-life transit example, the critical demands, which represent the switching point between the two competing service policies, have been derived. Our findings show that point deviation policy is more efficient at low-demand levels, while route deviation policy is a better choice at low-to-moderate demand levels. At unexpectedly high demand levels, route deviation policy is better able to accommodate rejected passengers than point deviation policy.

Document type: Article

Formal and computational modeling of anticipation mechanisms of resilience in the complex sociotechnical air transport system

Scipedia content — Mon, 22 Mar 2021 20:38:50 +0100

With ever-growing numbers of passengers and complexity of the air transport system, it becomes more and more of a challenge to manage the system in an effective, safe, and resilient manner. This is especially evident when disruptions occur. Understanding and improving resilience of the air transport system and its adaptive capacity to disruptions is essential for the system’s uninterrupted successful performance. Using theoretical findings from behavioral sciences, this paper makes the first steps towards formalization of the adaptive capacity of resilience of the air transport system with a particular focus on its ability to anticipate. To this end, an expressive logic-based language called Temporal Trace Language is used. The proposed approach is illustrated by a case study, in which anticipatory mechanisms are implemented in an agent-based airport terminal operations model, to deal with a disruptive scenario of unplanned and challenging passenger demand at the security checkpoint. Results showed that the timing of an adaptive action could have a significant influence on reducing the risk of saturation of the system, where saturation implies performance loss. Additionally, trade-off relations were obtained between cost, corresponding to the extra resources mobilized, and the benefits, such as a decrease in risk of saturation of the passenger queue.

Document type: Article

Effectiveness and Optimization of Harbour Tug Fleet

Scipedia content — Mon, 22 Mar 2021 20:34:44 +0100

"jats:p" Determination of efficiency and optimization harbour tug fleet is based on simulation of fleet work and usage for this the methods of ship dynamics and probability theory. Visiting the port transport vessels of possible types is considered as random stream of given intensity. This stream is distributed over the berths. Productivities of berths are given random variables. Random variables are also characteristics of weather conditions in the harbour basin. Tug fleet is represented by the collection of existing port tugs of different types. Work of tugs is determined by operations of approaching to ships, escorting theirs in the near-port waters, posting on the approach channels, transportation within the port waters, berthing, unberthing and going out the ship from the port with the repetition of functioning operations in reverse order. Selection of tugs to service the next arriving or departing ship is dependent from the intensity of the current weather conditions in the port and busyness of tugs in operations with other ships. Work fleet is considered on the conditional time interval of one year. In this time the efficiency of the tug fleet is defined by economic indexes of fulfilment of all towing operations and operations on maintenance tugs. Optimization of the fleet composition is carried out according to the criteria required minimum total bollard pull, low cost and high profit. Based on performed research a program for calculating the efficiency and optimization of the port towing fleet is composed. The program can be adapted to any port with whatever types of tugs.

Document type: Article

Real-Time Prediction of Lane-Based Queue Lengths for Signalized Intersections

Scipedia content — Mon, 22 Mar 2021 20:29:08 +0100

Queue length is one of the most important traffic evaluation indexes for traffic signal control at signalized intersections. Most previous studies have focused on estimating queue length, which cannot be predicted effectively. In this paper, we applied the Lighthill–Whitham–Richards shockwave theory and Robertson’s platoon dispersion model to predict the arrival of vehicles in advance at intervals of 5 seconds. This approach fully described the relationship between disparate upstream traffic arrivals (as a result of vehicles making different turns) and the variation of incremental queue accumulation. It also addressed the shortcomings of the uniform arrival assumption in previous research. In addition, to predict the queue length of multiple lanes at the same time, we integrated the prediction of the traffic volume proportions in each lane using the Kalman filter. We tested this model in a field experiment, and the results showed that the model had satisfactory accuracy. We also discussed the limitations of the proposed model in this paper.

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Sustainable solutions for internal mobility in spread university campuses

Scipedia content — Mon, 22 Mar 2021 20:26:46 +0100

The advent of alternative vehicle technologies such as Electrical Vehicles (EVs) is an efficient effort to reduce the emission of carbon oxides and nitrogen oxides. Ironically, EVs poses concerns related to vehicle recharging and management. Due to the significance of charging station infrastructure, electric vehicles’ charging stations deployment is investigated in this work. Its aim is to consider several limitations such as the power of charging station, the average time needed for each recharge, and traveling distance per day. Initially, a mathematical formulation of the problem is framed. Then, this problem is optimized by application of Genetic Algorithm (GA), with the objective to calculate the necessary number of charging stations then finding the best positions to locate them to satisfy the clients demand.

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Delay Causes Distribution: EU vs Croatian Coastal Airports

Scipedia content — Mon, 22 Mar 2021 20:18:31 +0100

The growth in air traffic in recent decades in Europe has consequently caused aircraft delays due to insufficient capacities of airspace and airports. Primary and reactionary delays at certain European and Croatian coastal airports in 2014 are analyzed in the paper according to CODA methodology and classified according to main flight delays causes. The largest share of delay minutes at the Croatian coastal airports (75%) are related to reactionary delays, ranging from around 20% to 60% of total delay at the most congested European airports. Special emphasis is given to the analyses of rotational reactionary delay, and the results indicate that the share of reactionary delay in total delay at the Split airport is significantly higher compared to selected European airports, which may be explained by delays propagated from air traffic network and limited airport capacity. The total recorded delay at Croatian coastal airports is minor compared to total recorded delay in the European air traffic system, but delay patterns are quite similar, especially during peak summer months.

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Analysis of the impact of an operator’s workstation on the safety of functioning of selected road transport systems

Scipedia content — Mon, 22 Mar 2021 20:11:37 +0100

Modern times are characterized by fast economic and social development. However, not all spheres of life have developed in a sustainable manner, for example some elements of anthropotechnical systems are still far from being sustainable. This results in low safety level of these systems involving high risk of injury or death caused by road accidents. Transport systems of the type Human-Machine-Environment , where undesired events are caused by human behavior, belong to such systems. The author of this study has addressed the issues connected with the impact of man-made objects on their operation safety. The objects in question are selected transport systems and the study subject is assessment of the equipment operator’s behavior. The main goal of this study is to provide assessment and analysis of the impact of transport means ergonomics on the quality of transport services they provide. The research object are delivery trucks with the maximum vehicle weight up to 3.5t. The first part of the study contains identification of the factors and threats which affect functioning of transport systems. Further, ergonomics criterion is defined and the factors affecting ergonomics of selected transport means are provided. A questionnaire survey was performed with participation of professional drivers who were asked to identify the factors which have an adverse effect on the safety of the transport process as well as factors that increase the drivers’ comfort of work. Basing on this, an analysis of the results was performed and negative aspects involved in driving ergonomics were identified.

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Research on Urban Logistics Competitiveness in Fujian Province Based on Factor Analysis and Cluster Analysis

Scipedia content — Mon, 22 Mar 2021 20:08:45 +0100

As an important province in the southeast coastal area, Fujian is composed of 9 cities. Due to various economic, political and geographical influences, the logistics development of these cities is uneven. Based on the analysis of the factors affecting the competitiveness of urban logistics, this paper establishes the evaluation index system of urban logistics competitiveness. Factor analysis is used to evaluate the logistics competitiveness index of each city in Fujian Province, and the comprehensive score and ranking of the logistics competitiveness of each city are obtained. Cluster analysis is used to divide 9 cities in Fujian into 4 categories, and the reasons for the results are analyzed.

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Priority Transfer Management Algorithm, Based on Interaction of the Public Transport Dispatch Systems Information and Traffic Lights Control

Scipedia content — Mon, 22 Mar 2021 20:08:02 +0100

"jats:p"The article is dedicated to the multi agent approach for urban public transport dispatch system to organize priority transfer management, based on interaction with traffic lights control system. The article deals with the issue of urban passenger transport priority transfer of signalized intersections. Priority transfer management algorithm developed by the authors based on interaction of traffic lights control and public transport dispatch systems. The authors considered the role of agents in interaction process of traffic lights control and public transport dispatch systems for implementation of the buses priority passage. Criterion for decision making taking into account savings and loses of time of all participants of traffic at the intersection. The results of simulation modelling of priority public transport passage a signalized intersection are presented

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Book review on cognitive engineering and safety organization in air traffic management

Scipedia content — Mon, 22 Mar 2021 20:05:51 +0100

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Characteristics of variable speed limit systems

Scipedia content — Mon, 22 Mar 2021 20:04:35 +0100

The control algorithm used for deciding on the speed limit in variable speed limit systems is crucial for the performance of the systems. The algorithm is designed to fulfil the purpose of the variable speed limit system, which can be one or several of the following aspects: increasing safety, increasing efficiency and decreasing environmental impacts. Today, many of the control algorithms used in practice are based on fixed thresholds in speed and/or flow. Therefore, they are not necessarily reflecting the current traffic conditions. Control algorithms with a greater level of complexity can be found in the literature. In this paper, four existing control algorithms are investigated to conclude on important characteristics affecting the performance of the variable speed limit system. The purpose of the variable speed limit system and, consequently, the design of the control algorithm differ. Requirements of the investigated control algorithms are that they should be easy to interpret and the execution time should be short. The algorithms are evaluated through microscopic traffic simulation. Performance indicators related to traffic safety, traffic efficiency and environmental impacts are presented. The results show that the characteristics of the variable speed limit system and the design of the control algorithm will have effect on the resulting traffic performance, given that the drivers comply with the variable speed limits. Moreover, the time needed to trigger the system, the duration and the size of speed limit reductions, and the location of the congestion are factors of importance for the performance of variable speed limit systems. "p"Funding Agencies|Swedish Transportation Administration (Trafikverket)

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CO"sub"2"/sub" Pipeline Design: A Review

Scipedia content — Mon, 22 Mar 2021 20:03:54 +0100

There is need to accurately design pipelines to transport the expected increase of CO2 captured from industrial processes after the signing of the Paris Climate Agreement in 2016. This paper reviews several aspects of CO2 pipeline design with emphasis on pressure drop and models for the calculation of pipeline diameter. Two categories of pipeline equations were identified. The first category is independent of pipeline length and has two different equations. This category is used to specify adequate pipeline diameter for the volume of fluid transported. The optimum economic pipe diameter equation (Eq. 17) with nearly uniform resultant velocity values at different flow rates performed better than the standard velocity flow equation (Eq. 20). The second category has four different equations and is used to calculate pipeline pressure drop or pipeline distance for the installation of booster stations after specifying minimum and maximum pipeline pressures. The hydraulic equation is preferred because it gave better resultant velocity values and the closest diameter value obtained using Aspen HYSYS (V.10) simulation. The effect of impurities on the pressure behaviour and optimal pipeline diameter and pressure loss due to acceleration were ignored in the development of the models. Further work is ongoing to incorporate these effects into the models.

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Measuring the Influences and Impacts of Signalized Intersection Delay Reduction on the Fuel Consumption, Operation Cost and Exhaust Emissions

Scipedia content — Mon, 22 Mar 2021 20:01:54 +0100

With the rapid urban expansion and economic development, vehicle fuel dissipation and exhaust emissions have been identified as major energy wastage and urban air pollutions in Kalar City and Iraqi Kurdistan Region in general. Traffic congestion is a growing problem in Kalar City and other urban areas. As it increases, the delay at the transportation network will increase. Any increase of the delay in the transportation network will reflect negatively by increasing the delay at the signalized intersections. Therefore, a study on delay and its relation to fuel consumption, operation cost and emissions at signalized intersection are necessary. This paper, studies the influences and impacts of signalized intersection delay reduction on the fuel consumption, operation cost, and exhaust emissions. A simulation is carried out to evaluate the existing conditions of selected intersections by estimating the intersection delay, operation cost, and emissions. The simulation results show that fuel consumption, operation cost, and emissions are high and directly proportional to the intersection delay. To reduce intersection delay, a signal timing optimization is carried out to the selected intersections. The optimization results show that the delay reduction has a significant influence and impacts in reducing; fuel wastage, operation cost, and exhaust emissions.

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Transfer Robustness Optimization for Urban Rail Transit Timetables

Scipedia content — Mon, 22 Mar 2021 19:58:30 +0100

A good timetable is required to not only be efficient, but also yield effectiveness in preventing and counteracting delays. When travelling via urban rail transit networks, transferring passengers may miss their scheduled connecting train because of a feeder train delay that results in them experiencing increased travel costs. Considering that running time supplements and transfer buffer times yield different effects on the travel plans of transferring and nontransferring passengers, we formulate an expected extra travel cost (EETC) function to appropriately balance efficiency and robustness, which is then implemented in the construction of a robust transfer optimization model with the objective of minimizing the total EETC. Next, to improve the computational efficiency, we propose an approximate linearization approach for the EETC function and introduce two types of binary variables and auxiliary substitution variables to convert the nonlinear model to a mixed-integer linear model. Experimental results show that our proposed method can yield practically applicable solutions with significant reductions in both EETC and probability of missing a transfer.

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Examining the Relationship between Household Vehicle Ownership and Ridesharing Behaviors in the United States

Scipedia content — Mon, 22 Mar 2021 19:51:26 +0100

To improve the sustainability and efficiency of transport systems, communities and government agencies throughout the United States (US) are looking for ways to reduce vehicle ownership and single-occupant trips by encouraging people to shift from driving to using more sustainable transport modes (such as ridesharing). Ridesharing is a cost-effective, sustainable and effective alternative transportation mode that is beneficial to the environment, the economy and society. Despite the potential effect of vehicle ownership on the adoption of ridesharing services, individuals&rsquo

ridesharing behaviors and the interdependencies between vehicle ownership and ridesharing usage are not well understood. This study aims to fill the gap by examining the associations between household vehicle ownership and the frequency and probability of ridesharing usage, and to estimate the effects of household vehicle ownership on individuals&rsquo

ridesharing usage in the US. We conducted zero-inflated negative binomial regression models using data from the 2017 National Household Travel Survey. The results show that, in general, one-vehicle reduction in households was significantly associated with a 7.9% increase in the frequency of ridesharing usage and a 23.0% increase in the probability of ridesharing usage. The effects of household vehicle ownership on the frequency of ridesharing usage are greater for those who live in areas with a higher population density than those living in areas with a lower population density. Young people, men, those who are unable to drive, individuals with high household income levels, and those who live in areas with rail service or a higher population density, tend to use ridesharing more frequently and are more likely to use it. These findings can be used as guides for planners or practitioners to better understand individuals&rsquo

ridesharing behaviors, and to identify policies and interventions to increase the potential of ridesharing usage, and to decrease household vehicle ownership, depending on different contextual features and demographic variables. Comprehensive strategies that limit vehicle ownership and address the increasing demand for ridesharing have the potential to improve the sustainability of transportation systems.

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The Sustainability of Shared Mobility in London: The Dilemma for Governance

Scipedia content — Mon, 22 Mar 2021 19:50:49 +0100

The role of governments in the regulation of potentially beneficial low carbon practices, such as car sharing, has proved difficult, as there are many different actors involved and as existing practices can be undermined. The mobility sector provides clear evidence of these dilemmas, as a wide range of users need to be engaged in the discourse over the innovations, and as existing governance structures may be unsuitable for addressing both the opportunities and limitations of innovation. This paper focuses on the sustainability implications of shared mobility and the need for new approaches to governance. A qualitative study of car sharing in London is used to examine the ideas, incentives, and institutions of the key actors involved in this sharing sector. The elements of change and continuity in the emerging sharing economy indicate the different possibilities for enhancing sustainable mobility. Any search for an alternative governance regime should take account of the ideational factors that would require an understanding of the different incentives needed to accommodate the full range of actors involved with the sharing economy.

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Prospective Life Cycle Assessment of the Increased Electricity Demand Associated with the Penetration of Electric Vehicles in Spain

Scipedia content — Mon, 22 Mar 2021 19:44:02 +0100

The penetration of electric vehicles (EV) seems to be a forthcoming reality in the transport sector worldwide, involving significant increases in electricity demand. However, many countries such as Spain have not yet set binding policy targets in this regard. When compared to a business-as-usual situation, this work evaluates the life-cycle consequences of the increased electricity demand of the Spanish road transport technology mix until 2050. This is done by combining Life Cycle Assessment and Energy Systems Modelling under three alternative scenarios based on the low, medium, or high penetration rate of EV. In all cases, EV deployment is found to involve a relatively small percentage (

Experimental Study of the Low-Cycle Fatigue in Double-Walled Hollow Pipe Members

Scipedia content — Mon, 22 Mar 2021 19:43:27 +0100

This paper introduces a double-walled hollow pipe (DWHP) that demonstrates good corrosion resistance and mechanical properties and that can be used in pipeline transportation and structural stress components in marine, freshwater, and corrosive environments. We designed and machined the specimens to meet the bending bearing capacity using a cross section method. We conducted low-cycle loading tests of the specimens to investigate the energy dissipation capacity of the DWHP, the effects of different geometrical parameters, and the concrete-filled strength of the DWHP on energy dissipation capacity. The results show that the failure forms of the specimens are similar. The geometrical characteristics of the specimens, the cohesive function between the concrete and the steel plate, and the strength of the concrete-filled pipe showed a significant influence on the mechanical properties of the specimens. Hysteretic curves are plump and possess a high capacity for energy dissipation. The energy dissipation capacity of the specimen decreases with an increase in the slenderness ratio. The slope of strength degradation decreases with any increase in the strength of the concrete-filled pipe. We optimized the section design of the component by improving the constraint effect coefficient, and we effectively improved its stability by adding stiffeners to the inner side of the outer wall of steel.

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Context-Based Path Prediction for Targets with Switching Dynamics

Scipedia content — Mon, 22 Mar 2021 19:32:06 +0100

Anticipating future situations from streaming sensor data is a key perception challenge for mobile robotics and automated vehicles. We address the problem of predicting the path of objects with multiple dynamic modes. The dynamics of such targets can be described by a Switching Linear Dynamical System (SLDS). However, predictions from this probabilistic model cannot anticipate when a change in dynamic mode will occur. We propose to extract various types of cues with computer vision to provide context on the target’s behavior, and incorporate these in a Dynamic Bayesian Network (DBN). The DBN extends the SLDS by conditioning the mode transition probabilities on additional context states. We describe efficient online inference in this DBN for probabilistic path prediction, accounting for uncertainty in both measurements and target behavior. Our approach is illustrated on two scenarios in the Intelligent Vehicles domain concerning pedestrians and cyclists, so-called Vulnerable Road Users (VRUs). Here, context cues include the static environment of the VRU, its dynamic environment, and its observed actions. Experiments using stereo vision data from a moving vehicle demonstrate that the proposed approach results in more accurate path prediction than SLDS at the relevant short time horizon (1 s). It slightly outperforms a computationally more demanding state-of-the-art method.

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Probabilistic En Route Sector Traffic Demand Prediction Based upon Statistical Analysis of Error Distribution Characteristics

Scipedia content — Mon, 22 Mar 2021 19:28:39 +0100

In China, air traffic congestion has become increasingly prominent and tends to spread from terminal areas to en route networks. Accurate and objective traffic demand prediction could alleviate congestion effectively. However, the usual demand prediction is based on conjecture method of flying track, and the number of aircraft flying over a sector in a set time interval could be inferred through the location information of any aircraft track. In this paper, we proposed a probabilistic traffic demand prediction method by considering the deviations caused by random events, such as the change of departure or arrival time, the temporary change in route or altitude under severe weather conditions, and unscheduled cancellation for a flight. The probabilistic method quantifies these uncertain factors and presents numerical value with its corresponding probability instead of the deterministic number of aircraft in a sector during a time interval. The analysis results indicate that the probabilistic traffic demand prediction based on error distribution characteristics achieves an effective match with the realistic operation in airspace of central and southern China, which contributes to enhancing the implementation of airspace congestion risk management.

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Impact of passenger engagement through road safety bus stickers in public service vehicles on road traffic crashes in Zambia: a randomized controlled trial

Scipedia content — Mon, 22 Mar 2021 19:22:08 +0100

Road Traffic Crashes (RTCs) are the third highest cause of death in Zambia, claiming about 2000 lives annually, with pedestrians and cyclists being the most vulnerable. Human error accounts for 87.3% of RTCs. Minibus and big bus public service vehicles (PSVs) are among the common vehicle types involved in these crashes. Given the alarmingly high rate of road traffic crashes involving PSV minibuses and big buses within Zambia, there is a need to mitigate this through innovative solutions. In other settings, it has been shown that stickers in PSVs encouraging passengers to speak out against reckless driving can reduce RTCs, but it is unclear whether such an intervention could work in Zambia. Based on this evidence, the Zambia Road Transport and Safety Agency (RTSA) has developed a road safety bus sticker campaign for PSVs and before national scale-up, RTSA is interested in evidence of the impact of these stickers. This evaluation will be a stratified two-arm randomized controlled trial with a one-to-one ratio. The sample will be stratified by vehicle type, thus creating a two-arm trial for minibuses and a separate two-arm trial for big buses. The sample will include 2110 minibuses and 300 big buses from four towns in Zambia. The primary outcome of interest will be the difference in the rate of RTCs over a 14-month period (7-months before the intervention and 7 months after) between buses with and without the new RTSA road safety bus stickers. This study will provide evidence on the impact of the Zambian sticker program on road traffic crashes as implemented through minibuses and big buses, that can help inform the scale up of a national ‘Zambia road safety bus sticker campaign’. PACT-R, PACTR201711002758216 . Registered 13 November 2017-Retrospectively registered.

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Fuel-Efficient Driving Strategies for Heavy-Duty Vehicles: A Platooning Approach Based on Speed Profile Optimization

Scipedia content — Mon, 22 Mar 2021 19:21:23 +0100

A method for reducing the fuel consumption of a platoon of heavy-duty vehicles (HDVs) is described and evaluated in simulations for homogeneous and heterogeneous platoons. The method, which is based on speed profile optimization and is referred to as P-SPO, was applied to a set of road profiles of 10 km length, resulting in fuel reduction of 15.8% for a homogeneous platoon and between 16.8% and 17.4% for heterogeneous platoons of different mass configurations, relative to the combination of standard cruise control (for the lead vehicle) and adaptive cruise control (for the follower vehicle). In a direct comparison with MPC-based approaches, it was found that P-SPO outperforms the fuel savings of such methods by around 3 percentage points for the entire platoon, in similar settings. In P-SPO, unlike most common platooning approaches, each vehicle within the platoon receives its own optimized speed profile, thus eliminating the intervehicle distance control problem. Moreover, the P-SPO approach requires only a simple vehicle controller, rather than the two-layer control architecture used in MPC-based approaches.

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Female non-smokers’ environmental tobacco smoking exposure by public transportation mode

Scipedia content — Mon, 22 Mar 2021 19:19:33 +0100

Background This study aimed to analyze environmental tobacco smoking exposure in female nonsmokers by public transportation mode using representative data of Koreans. Methods Data from the Second Korean National Environmental Health Survey (2012–2014) were analyzed. Urine cotinine was analyzed by public transport behavior, secondhand smoke exposure, socioeconomic factors, and health-related factors. Participants were 1322 adult females; those with the top 75% urine cotinine concentrations were assigned to the high exposure group. A logistic regression analysis was performed considering appropriate weights and stratification according to the sample design of the Second Korean National Environmental Health Survey. Results The geometric mean of urine cotinine concentrations differed according to public transportation modes: subway (1.66 μg/g creatinine) bus (1.77 μg/g creatinine), and taxi (1.94 μg/g creatinine). The odds ratio [OR] was calculated for the high exposure group. The OR of the taxi (2.39; 95% confidence interval, 1.00–5.69) was statistically significantly higher than the subway value (reference), and marginally significant after adjusted with life style, sociodemographic factors and involuntary smoking frequency (2.42, 95% confidence interval, 0.97–6.04). Conclusions The odds ratio of passengers who mainly used taxis was marginally significantly higher than those of passengers who used subways and buses after adjusted with life style and sociodemographic factors. Implementation of supplementary measures and further studies on exposure to environmental tobacco smoking in taxis are warranted.

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Analysis of Systems Ensuring the Acquisition of Real-Time Cartographic Navigation Information

Scipedia content — Mon, 22 Mar 2021 19:18:12 +0100

"jats:p"Electronic Chart Display and Information Systems (ECDIS), which are used on vessels and can replace paper charts, allow to obtain and display on electronic charts information from basic and additional data sources. For the certified use of ECDIS instead of paper charts, it is necessary to ensure constant updating of Electronic Navigation Chart (ENC) data provided to vessels for use. The known visual and satellite observation systems intended for cartographic information update are costly, have low accuracy and do not allow to quickly update navigational charts in real-time mode. The stand-alone use of remotely piloted aircraft (RPA) will make it possible not only to substantially reduce costs and increase the accuracy of monitoring, but also to provide information in real-time mode.

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Assessing the operations of commuter rail: A case study in KRL commuter line of Jakarta Metropolitan Area

Scipedia content — Mon, 22 Mar 2021 19:17:53 +0100

Public transportation is considered to be able to handle several transportation problems, such as “the ancient” traffic congestion to “the contemporary” environmental impact. Rail transit, or also known as commuter rail, is one of the most important public transportation types since it could reduce effectively the traffic congestion. At this instant, service quality of commuter rail is essential to achieve the customer satisfaction. This research aims to assess the operations of commuter rail by assessing its service quality. The importance-performance and gap analysis (IPGA) based on nine criteria was applied to accomplish the objective. A case study was conducted in KRL commuter line of Jakarta Metropolitan Area which is operated by P.T. Kereta Commuter Indonesia. The result shows that the safety criterion has the highest relative importance score and the fare has the highest relative performance score. The IPGA technique then was employed to build strategies based on the relative importance and performance from the passengers’ point of view.

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Shared Autonomous Taxi System and Utilization of Collected Travel-Time Information

Scipedia content — Mon, 22 Mar 2021 19:17:31 +0100

Shared autonomous taxi systems (SATS) are being regarded as a promising means of improving travel flexibility. Each shared autonomous taxi (SAT) requires very precise traffic information to independently and accurately select its route. In this study, taxis were replaced with ride-sharing autonomous vehicles, and the potential benefits of utilizing collected travel-time information for path finding in the new taxi system examined. Specifically, four categories of available SATs for every taxi request were considered: currently empty, expected-empty, currently sharable, and expected-sharable. Two simulation scenarios—one based on historical traffic information and the other based on real-time traffic information—were developed to examine the performance of information use in a SATS. Interestingly, in the historical traffic information-based scenario, the mean travel time for taxi requests and private vehicle users decreased significantly in the first several simulation days and then remained stable as the number of simulation days increased. Conversely, in the real-time information-based scenario, the mean travel time was constant. As the SAT fleet size increased, the total travel time for taxi requests significantly decreased, and convergence occurred earlier in the historical information-based scenario. The results demonstrate that historical traffic information is better than real-time traffic information for path finding in SATS.

Document type: Article

Public Awareness towards Sustainable Transportation in Shah Alam, Malaysia

Scipedia content — Mon, 22 Mar 2021 19:17:10 +0100

This paper studied the awareness of an urban population to use sustainable vehicles and their readiness to reduce car usage. Data were collected through a survey of 384 vehicle users in Shah Alam, Selangor. Results suggested that the majority were not ready to consider cycling and walking as alternatives. About to environmental awareness, the majority showed their awareness of the dangers of motor vehicles towards the environment. However, they refused to use more sustainable mode oftravelling. Among other reasons provided as “refusal” regarding of sustainable vehicles,applicationwas hot weather, surrounding safety factor and inefficient public transport services.Keywords: Sustainable vehicles; environmental awareness, travel behavioureISSN 2398-4295 © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. http://dx.doi.org/10.21834/ajbes.v3i11.109

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Sensorless control strategy for light-duty EVs and efficiency loss evaluation of high frequency injection under standardized urban driving cycles

Scipedia content — Tue, 16 Feb 2021 13:46:31 +0100

Sensorless control of Electric Vehicle (EV) drives is considered to be an effective approach to improve system reliability and to reduce component costs. In this paper, relevant aspects relating to the sensorless operation of EVs are reported. As an initial contribution, a hybrid sensorless control algorithm is presented that is suitable for a variety of synchronous machines. The proposed method is simple to implement and its relatively low computational cost is a desirable feature for automotive microprocessors with limited computational capabilities. An experimental validation of the proposal is performed on a full-scale automotive grade platform housing a 51¿kW Permanent Magnet assisted Synchronous Reluctance Machine (PM-assisted SynRM). Due to the operational requirements of EVs, both the strategy presented in this paper and other hybrid sensorless control strategies rely on High Frequency Injection (HFI) techniques, to determine the rotor position at standstill and at low speeds. The introduction of additional high frequency perturbations increases the power losses, thereby reducing the overall efficiency of the drive. Hence, a second contribution of this work is a simulation platform for the characterization of power losses in both synchronous machines and a Voltage Source Inverters (VSI). Finally, as a third contribution and considering the central concerns of efficiency and autonomy in EV applications, the impact of power losses are analyzed. The operational requirements of High Frequency Injection (HFI) are experimentally obtained and, using state-of-the-art digital simulation, a detailed loss analysis is performed during real automotive driving cycles. Based on the results, practical considerations are presented in the conclusions relating to EV sensorless control.

Peer Reviewed

Document type: Article

Online leak diagnosis in pipelines using an EKF-based and steady-state mixed approach

Scipedia content — Tue, 16 Feb 2021 13:44:43 +0100

This paper proposes a methodology for leak detection and isolation (LDI) in pipelines based on data fusion from two approaches: a steady-state estimation and an Extended Kalman Filter (EKF). The proposed method considers only pressure head and flow rate measurements at the pipeline ends, which contain intrinsic sensor and process noise. The LDI system is tested in real-time by using an USB data acquisition device that is implemented in MATLAB environment. The effectiveness of the method is analyzed by considering: online detection, location as well as quantification of non-concurrent leaks at different positions. The leak estimation error average is less than 1% of the flow rate and less than 3% in the leakage position. Furthermore, the incorporation of a steady-state estimation shows that the solution of the LDI problem has improved significantly with respect to the one that only considers the EKF estimation. An experimental analysis was also performed on the effectiveness of the proposed approach for different sampling rates and for different leakage positions

Peer Reviewed

An empirical evaluation of changes in public service obligations in Spain

Scipedia content — Tue, 16 Feb 2021 13:39:56 +0100

Public Service Obligations are a key mechanism for countries to improve connections among islands and remote regions with the Continent. While Public Service Obligations are allowed by the European Commission, they represent an interference with free market competition, and impact on the entrance of competitors, prices and service frequency. This study employs Canarian air market data for 2002–2015 to econometrically evaluate the effects of two changes in European policy on the number of passengers transported. The results point to the need to make market access more flexible to benefit society by generating increases in the volume of passengers moved.

Assessment of the North European free route airspace deployment

Scipedia content — Tue, 16 Feb 2021 13:38:53 +0100

Free Route Airspace is an operational concept for the modernization of the airspace, addressed to improving the efficiency of the flights. It also aims at the environmental friendly performance area by reducing the emissions from fuel burnt. But these benefits should not derive in a loss of safety. Several areas are introducing free route as part of the Single European Sky Airspace Research programme (SESAR). This paper assesses the Northern Europe Free Route Airspace deployment, where two SESAR solutions are combined: the Free Route Airspace and the Functional Airspace Blocks. This assessment is produced using fast-time simulations and presented from a safety perspective using two indicator sets: the aircraft loss of separation and the airspace complexity. The number of potential separation losses, together with complexity metrics, such as adjusted density, potential horizontal, vertical and/or speed interactions, are presented for different free route deployment status. Results reflect that from the safety perspective the free route deployment in North Europe did not present notable changes in terms of the selected indicators, despite of the increase of traffic of last years.

Peer Reviewed

Challenges to Standardizing Emissions Calculation of Logistics Hubs as Basis for Decarbonizing Transport Chains on a Global Scale

Scipedia content — Tue, 16 Feb 2021 13:16:44 +0100

Carbon footprinting is regarded as one means of enhancing transparency on where greenhouse gas (GHG) emissions are produced within a transport chain and thus limiting the emissions and improving the efficiency of transport and transhipment on both the demand and supply sides of the market. To meet global GHG reduction targets and to realize sustainable transport chains, standardization of emissions calculations is progressing swiftly. One of the core requirements in the next steps of the standardization effort is harmonization of level of detail of the various transport modes. In particular logistics hubs have been identified as relevant for such a development and whereas developments for transport modes such as rail, road, air, or water are pursued by industry representatives and their organizations, logistics hubs have no organization which is intrinsically motivated to further develop an approach to emissions calculation. Research can deliver an important and valuable contribution here. Therefore, based on extensive empirical research in the form of questionnaires and real-life examples of emissions calculation, this paper describes the motivations and barriers currently experienced by shippers and logistics service providers when computing emissions. Possible approaches to overcoming these barriers and contributing to the further improvement of the level of maturity of emissions calculation of logistics hubs are described and discussed. The paper closes with an outlook on further requirements toward transport chain emissions calculation standardization developments.

Time-lapse acoustic monitoring of deteriorating pipes

Scipedia content — Tue, 16 Feb 2021 13:08:36 +0100

In-service degradation of a pipe section is monitored in real time with torsional guided waves which can resolve 5% damage to the internal wall. We use a single permanently installed source–receiver pair as opposed to the current state-of-the-art sensor rings. There is no baseline subtraction requirement as a single reflection coefficient is derived by internal referencing of the time trace. Even with continuously operating pump vibration, there is enough acoustic signal for confident damage localization. Since pipelines wear out gradually in industrial installations, the acoustic footprint is similar to that previously determined in periodically damaged pipes. The reflective method can thus be applied successfully to monitor structural health in industrial pipelines during operation as opposed to the current state-of-the-art guided wave inspection approaches using near-weld reflection techniques along with disassembled and re-assembled sensor rings.

Keep Moving, Stay Tuned: The Construction of Flow in and through Radio Traffic Reports

Scipedia content — Tue, 16 Feb 2021 13:03:51 +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.

A Decision-Support Framework for the Stowage of Maritime Containers in Inland Shipping

Scipedia content — Tue, 16 Feb 2021 12:58:22 +0100

The typical voyage of a barge transporting maritime containers inland, consists of visiting a set of terminals where loading/unloading operations occur. The required stowage plans must meet stability requirements during all transport phases and avoid costly re-handling operations. In this paper, we formalize this problem and consider a typical dry-port transport system. We propose a comprehensive mathematical model that seeks to maximize stowed containers. To solve it, we develop a hybrid metaheuristic approach, based on local search and an industrial solver. Numerical experiments, based on real-world data, provide insights into the performances of the proposed framework and current stowage practices.

The use of the analytic hierarchy process for admission to an air traffic control department

Scipedia content — Tue, 16 Feb 2021 12:56:32 +0100

Meeting the need for qualified staff in the field of air traffic control depends primarily on selection of appropriate candidates among many applicants. The selection of competent air traffic controllers, who play a vital role in the air traffic system, is of critical importance and is usually conducted through multi-stage examinations. It is also important to use correct methods in the selection process in order to identify the most suitable candidates. In particular, the application of subjective examinations, such as interviews in a standard way, and determination and standardization of criteria can assist in selecting the right candidates. Within this context, the student selection process in an air traffic control department is investigated, with the aim of supporting the interview examination through the Analytic Hierarchy Process. The criteria weighting is determined by expert opinion. Thirty-nine candidates are ranked according to the AHP, with the current and proposed rankings being compared. As a result, the ranking has changed significantly with the proposed approach.

Aircraft classification for efficient modelling of environmental noise impact of aviation

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

With the environmental externalities of civil aviation under unprecedented scrutiny, and with the projected\\ud significant increase in air traffic demand over the next few decades, fleet-level studies are required to assess the\\ud potential benefit of novel aircraft technologies and operational procedures for minimizing environmental impact\\ud of aviation. Using a statistical classification process, the UK commercial aircraft fleet is reduced to four representative-\\ud in-class aircraft on the basis of aircraft physical characteristics, and aircraft noise and engine exhaust\\ud emissions. These four representative aircraft, that appropriately capture the noise and emissions characteristics\\ud for each category within the UK commercial fleet, are also selected to be used as baseline cases for the\\ud high-level assessment of the environmental benefit of novel aircraft technologies. For the particular case of\\ud aviation noise, the modelling tools are highly sensitive to the number of aircraft types in the flight schedule. A\\ud reduction of about 80% in computational time with relatively minor decrease in accuracy (between −4% and\\ud +5%) is observed when the whole aircraft fleet is replaced with the four representative-in-class aircraft for\\ud computing noise contours. Therefore, the statistical classification and selection of representative-in-class aircraft\\ud presented in this paper is a valid approach for the rapid and accurate computation of a large number of exploratory\\ud cases to assess aviation noise reduction strategies.

The urban recharging infrastructure design problem with stochastic demands and capacitated charging stations

Scipedia content — Tue, 16 Feb 2021 12:49:05 +0100

In this study we develop an exact solution method to optimize the location and capacity of charging stations to satisfy the fast charging needs of electric vehicles in urban areas. Stochastic recharge demands, capacity limitations of charging stations and drivers’ route preferences (deviation tolerances) are simultaneously considered to address this challenging problem faced by recharging infrastructure planners or investors. Taking a scenario based approach to model demand uncertainty, we first propose a compact two stage stochastic programming formulation. We then project out the second stage decision variables from the compact formulation by describing the extreme rays of its polyhedral cone and obtain (1) a cut formulation that enables an efficient branch and cut algorithm to solve large problem instances (2) a novel characterization for feasible solutions to the capacitated covering problems. We test our algorithm on the Chicago metropolitan area network, by considering real world origin-destination trip data to model charging demands. Our results attest the efficiency of the proposed branch and cut algorithm and provide significant managerial insights.

A shortest path algorithm for the departure time and speed optimization problem

Scipedia content — Tue, 16 Feb 2021 12:48:46 +0100

We present a shortest-path algorithm for the departure time and speed optimization problem under traffic congestion. The objective of the problem is to determine an optimal schedule for a vehicle visiting a fixed sequence of customer locations to minimize a total cost function encompassing emissions cost and labor cost.We account for the presence of traffic congestion, which limits the vehicle speed during peak hours.We show how to cast this problem as a shortest-path problem by exploiting some structural results of the optimal solution. We illustrate the solution method and discuss some properties of the problem.

What externally presented information do VRUs require when interacting with fully Automated Road Transport Systems in shared space?

Scipedia content — Tue, 16 Feb 2021 12:45:16 +0100

the desire for deploying automated (“driverless”) vehicles increases, there is a need to understand how they might communicate with other road users in a mixed traffic, urban, setting. In the absence of an active and responsible human controller in the driving seat, who might currently communicate with other road users in uncertain/conflicting situations, in the future, understanding a driverless car’s behaviour and intentions will need to be relayed via easily comprehensible, intuitive and universally intelligible means, perhaps presented externally via new vehicle interfaces. This paper reports on the results of a questionnaire-based study, delivered to 664 participants, recruited during live demonstrations of an Automated Road Transport Systems (ARTS; SAE Level 4), in three European cities. The questionnaire sought the views of pedestrians and cyclists, focussing on whether respondents felt safe interacting with ARTS in shared space, and also what externally presented travel behaviour information from the ARTS was important to them. Results showed that most pedestrians felt safer when the ARTS were travelling in designated lanes, rather than in shared space, and the majority believed they had priority over the ARTS, in the absence of such infrastructure. Regardless of lane demarcations, all respondents highlighted the importance of receiving some communication information about the behaviour of the ARTS, with acknowledgement of their detection by the vehicle being the most important message. There were no clear patterns across the respondents, regarding preference of modality for these external messages, with cultural and infrastructural differences thought to govern responses. Generally, however, conventional signals (lights and beeps) were preferred to text-based messages and spoken words. The results suggest that until these driverless vehicles are able to provide universally comprehensible externally presented information or messages during interaction with other road users, they are likely to contribute to confusing and conflicting interactions between these actors, especially in a shared space setting, which may, therefore, reduce efficient traffic flow.

The role of integration in achieving sustainable benefits from airline alliances

Scipedia content — Tue, 16 Feb 2021 12:41:26 +0100

WOS: 000469422700005

Air transport is one of the industries where strategic alliances are most common. While alliance strategies by airlines are widespread, the performance and sustainability of alliances is currently in debate. However, the importance of the level of integration for the benefits from mergers and alliances in the literature is an important topic discussed. In this study, we relate the sustainability of alliances to the benefits gained from that cooperation and aimed to demonstrate the importance of the level of integration on the alliance benefits in the airline industry. To achieve this aim, after a comprehensive literature, we conducted a research on three global airline alliance members. The study comprises 26 international airlines who are members of one of global airline alliances - Star, Sky Team and Oneworld. The results suggest that there is a significant and positive relationship between level of integration of airlines to the global alliance and the alliance benefits gained from the alliance membership.

Scientific Research Projects Commission, Anadolu University [1401E019]

The authors acknowledge the support of Scientific Research Projects Commission, Anadolu University for sponsoring the project (1401E019).

Improving traffic management through consideration of uncertainty and stochastics in traffic flow

Scipedia content — Tue, 16 Feb 2021 12:39:30 +0100

In a bid to cost-effectively tackle congestion, traffic management is often seen as a key option to utilise road capacity. Prior to the application of traffic management measures, a-priori analysis allows the effectiveness of measures to be judged and where necessary adapted. However, current approaches do this without considering the effects of stochastic uncertainty and fluctuations in traffic flow. These stochastic effects have been shown to substantially influence the evaluation of traffic management measures. In this contribution, a methodological framework is proposed and demonstrated in a multi-part case study, applying approaches that explicitly consider stochastic variations and applications for traffic management. The results of the case study demonstrate the effectiveness of the models and highlight the necessity to consider uncertainty and fluctuations when a-priori evaluating traffic management measures. © 2018 World Conference on Transport Research Society

Autonomous Driving Progressed by oneM2M : The Experience of the AUTOPILOT Project

Scipedia content — Tue, 16 Feb 2021 12:38:41 +0100

The European Commission Horizon 2020 AUTOPILOT (AUTOmated driving Progressed by Internet Of Things) is aiming to exploit the IoT ecosystem to integrate connected cars and transform them in automated moving "objects". One of the key challenges encountered in the project is to ensure the interoperability of the different components and IoT platforms serving e.g. in-vehicle and road-side devices and sensors. The adopted solution is the use of Federated IoT platforms, with the oneM2M Interoperability Platform used to ensure that all components are able to communicate with each other. This paper provides a high-level description of the project and its goals and then concentrates on the importance to ensure interoperability support for IoT platforms using the standard IoT platform provided by oneM2M. © 2019 IEEE.

Collecting evidence from distributed sources to evaluate railway suicide and trespass prevention measures

Scipedia content — Tue, 16 Feb 2021 12:38:18 +0100

It can be difficult to select from available safety preventative measures, especially where there is limited evidence of effectiveness in different contexts. This paper describes application of a method to identify and evaluate wide-ranging preventative measures for rail suicide and trespass fatalities. Evidence from literature and industry sources was collated and reviewed in a two stage process to achieve consensus among experts on the likely effects of the measures and factors influencing their implementation. Multiple evaluation criteria were used to examine the measures from different perspectives. Fencing, awareness campaigns and different types of organisational initiatives were recommended for further testing. This is the first time evidence has been collected internationally across such a range of preventative measures. Commentary is provided on using this type of approach to select safety measures from a pool of prevention options, including how re-framing the scope of the exercise could identify alternative options for prevention. Practitioner summary: The findings give insight to how different measures work in different ways and how industry can consider this in strategic initiatives. The method could be used in future studies with different frames of reference (e.g. different timescales, level of ambition and safety context e.g. railway crossings or highway fatalities). Abbreviation: RESTRAIL: REduction of Suicides and Trespasses on RAILway property.

Optimization models for high-speed train unit routing problems

Scipedia content — Tue, 16 Feb 2021 12:34:26 +0100

Train unit routing problem determines the number of train units needed to carry out involved trips, which is a significant part of railway operation cost. In this paper, we focus on high-speed train unit routing problems, in which maintenance resource constraints both on time and distance are taken into account. Based on a connection network, this paper first proposes a general train unit routing model. Then, the general model is specialized to meet the circulation and maintenance conditions of high-speed train units in China, which is based on a special connection network with a two-day time horizon. A strategy is proposed to reduce the scale of the connection network, which improves the model’s solvability. Furthermore, an extension on multi-depot train unit routing problem is discussed. Finally, numerical experiments based on the real data of Chinese high-speed railway are carried out to verify the effectiveness and efficiency of the proposed mode and method.

Air traffic assignment based on daily population mobility to reduce aircraft noise effects and fuel consumption

Scipedia content — Tue, 16 Feb 2021 12:32:21 +0100

The paper first investigates the influence of daily mobility of population on evaluation of aircraft noise effects. Then, a new air traffic assignment model that considers this activity is proposed. The main objective is to reduce the number of people affected by noise via lowering as much as possible the noise exposure level L "sub"den"/sub" of individuals or groups of people who commute to the same locations during the day. It is hereby intended to reduce the noise impact upon individuals rather than to reduce the impact in particular – typically densely populated – areas. However, sending aircraft farther away from populated regions to reduce noise impact may increase fuel burn, thus affecting airline costs and sustainability. Therefore, a multi-objective optimization approach is utilized to obtain reasonable solutions that comply with overall air transport sustainability. The method aims at generating a set of solutions that provide proper balance between noise annoyance and fuel consumption. The reliability and applicability of the proposed method are validated through a real case study at Belgrade airport in Serbia. The investigation shows that there is a difference between the number of people annoyed (NPA) evaluated based on the census data and the NPA evaluated based on the mobility data. In addition, these numbers differ significantly across residential locations. The optimal results show that the proposed model can offer a considerable reduction in the NPA, and in some cases, it can gain up to 77%, while maintaining the same level of fuel consumption compared with the reference case.

Assessment of the risk related to environmental damage following major accidents in onshore pipelines

Scipedia content — Tue, 16 Feb 2021 12:30:43 +0100

Major accidents may cause both direct damages to the exposed population and damage to the environment, indirectly affecting the population by the contamination of land, surface water and groundwater. A wide attention was paid to date to the assessment of the direct risk for the population deriving from major accidents (fires, explosions, toxic releases). Less work was devoted to the quantitative assessment of the risk due to the environmental consequences of major accidents. In the present study, an innovative GIS-based approach was developed for the quantitative assessment of the risk caused by damage to the environment deriving from major accidents involving pipelines. The method allows the calculation of local and overall environmental risk indexes, expressed both in physical and monetary terms. These are structured so that in perspective they can be combined with the risk obtained for the exposed population, providing a comprehensive risk figure of the potential consequences of major accidents involving oil pipelines. A specific software tool was developed to support the application of the methodology. A real-life case-study is presented and discussed in order to assess the potentiality of the approach. The results confirm that, in the frame of safety guidelines and good practices for pipelines, the proposed methodology represents a useful tool to fulfil requirements concerning the comprehensive risk assessment of pipeline operation, providing useful information on safety-critical segments and on the expected severity and economic impact of spill scenarios. © 2018 Elsevier Ltd

Sensor motes for the exploration and monitoring of operational pipelines

Scipedia content — Tue, 16 Feb 2021 12:29:14 +0100

We report on a first field test in which miniaturized sensor motes were used to explore and inspect an operational pipeline by performing in situ measurements. The spherical sensor motes with a diameter of 39 mm were equipped with an inertial measurement unit (IMU) measuring 3-D acceleration, rotation, and magnetic field, as well as an ultrasound emitter. The motes were injected into the pipeline and traversed a 260-m section of it with the flow of water. After the extraction of the motes from the pipeline, the recorded IMU data were read out for the off-line analysis. Unlike dead-reckoning techniques, we analyze the IMU data to reveal structural information about the pipeline and locate pipe components, such as hydrants and junctions. The recorded data show different and distinct patterns that are a result of the fluid dynamics and the interaction with the pipeline. Using the magnetic data, pipe sections made from different materials and pipe components are identified and localized. A preliminary analysis on the motes’ interaction with the pipeline shows differences in pipe wall roughness and locates structural anomalies. The results of this field test show that sensor motes can be used as a versatile and cost-effective tool for exploration and inspection of a wide variety of pipelines.

Impacts on Road Network Performance and Equity

Scipedia content — Tue, 16 Feb 2021 12:28:35 +0100

Information-based demand measures using social routing advice are receiving increasing attention, as they are expected to be successful in reducing the traffic congestion. Such measures direct travelers toward routes that benefit the road network. As such, some travelers need to act socially and take a detour. This paper explores the impacts on network performance and equity that result from the application of a social routing service. We complement the existing work by using a large-scale real-world road network, by assessing impacts on the individual level and by discussing our findings in the light of observed individual compliance behavior obtained from a field experiment. Our results show that 3.6% of total travel time within our road network could be reduced when all trips are made in compliance with the received advice. However, based on the observed compliance behavior, a social routing service is expected to direct only a minority of travelers toward social routes. We show how the attained travel time savings vary with the assumed compliance rate, e.g., to achieve 50% of the potential travel time savings, about 30% of travelers need to be willing to take a detour. Moreover, we find that lower the compliance among travelers, the more the social travelers need to compensate for the selfish behavior of others by taking longer detours. Finally, we demonstrate that the impacts on network performance and equity highly depend on the spatial distribution of social travelers among origins and destinations.

Document type: Article

Scenario-based functional safety for automated driving on the example of valet parking

Scipedia content — Tue, 16 Feb 2021 12:24:51 +0100

New safety challenges have to be targeted due to the development of fully automated vehicles in the upcoming future. However, designing safe vehicle automation systems is essential. This work presents a scenario-based methodology for functional safety analysis according to the ISO 26262 using the example of automated valet parking . The vehicle automation system is decomposed into functional scenarios that can occur during operation. Potential malfunctions are identified for each scenario within a hazard analysis and risk assessment . Elaborated safety goals for automated valet parking are presented. © Springer Nature Switzerland AG 2019.