Scipedia: Documents published in 2016

Numerical Analysis of an Intercity Bus Structure: A Simple Unifilar Model Proposal to Assess Frontal and Semifrontal Crash Scenarios

Scipedia content — Tue, 23 Mar 2021 07:00:35 +0100

TO IMPROVE THE SAFETY OF THE INTERCITY BUS STRUCTURE AGAINST IMPACT SCENARIOS AND TO REDUCE THE INJURES AND DEATH IN TRAFFIC ACCIDENTS IT IS CRUCIAL IN A COUNTRY WITH CONTINENTAL DIMENSIONS LIKE BRAZIL, WHERE THE ROAD TRANSPORT MATRIX IS FUNDAMENTAL IN THE TRAFFIC OF PEOPLE AND GOODS. IN THIS CONTEXT IN THE PRESENT ARTICLE, A NUMERICAL MODEL OF AN INTERCITY BUS WAS BUILT WITH ELASTOPLASTIC BEAMS IMPLEMENTED IN A COMMERCIAL SOFTWARE LSDYNA. THIS MODEL WAS SUBMITTED TO DIFFERENT FRONTAL AND SEMI FRONTAL IMPACT CRASH SCENARIOS. WITH THIS MODEL WERE ANALYZED DIFFERENT ACCIDENTS WHICH HAPPENED IN THE BRAZILIAN HIGHWAYS, IT WAS ALSO SIMULATED A FRONTAL IMPACT TEST AND THE RESULTS OBTAINED WERE COMPARED WITH THE EXPERIMENTAL RESULTS. FINALLY THREE NUMERICAL APPROACHES WERE COMPARED, THEY ARE: A SIMPLE MODEL MADE WITH LUMPED MASSES AND NON-LINEAR SPRINGS SERIES CONNECTED, THE ELASTOPLASTIC BEAM MODEL AND THE CONVENTIONAL NON-LINEAR FINITE ELEMENT MODEL BUILT WITH SHELL ELEMENTS. THE DIFFERENT COMPARISONS CARRIED OUT LET US VALIDATE THE INTERCITY BUS MODEL CREATED USING ELASTOPLASTIC BEAM ELEMENTS AND PROPOSE TO USE THIS MODEL AS AN EFFECTIVE TOOL TO SEARCH FOR MORE EFFICIENT BUS STRUCTURAL CONFIGURATIONS AGAINST IMPACT SCENARIOS.

Document type: Article

Intelligent Controller Design for Quad-Rotor Stabilization in Presence of Parameter Variations

Scipedia content — Tue, 23 Mar 2021 06:57:57 +0100

The paper presents the mathematical model of a quadrotor unmanned aerial vehicle (UAV) and the design of robust Self-Tuning PID controller based on fuzzy logic, which offers several advantages over certain types of conventional control methods, specifically in dealing with highly nonlinear systems and parameter uncertainty. The proposed controller is applied to the inner and outer loop for heading and position trajectory tracking control to handle the external disturbances caused by the variation in the payload weight during the flight period. The results of the numerical simulation using gazebo physics engine simulator and real-time experiment using AR drone 2.0 test bed demonstrate the effectiveness of this intelligent control strategy which can improve the robustness of the whole system and achieve accurate trajectory tracking control, comparing it with the conventional proportional integral derivative (PID).

Document type: Article

Adaptive internal model control research in autonomous landing phase for a fixed-wing UAV

Scipedia content — Tue, 23 Mar 2021 06:31:20 +0100

utonomous landing is a very complex phase of flight for unmanned aerial vehicle (UAV). Adaptive internal model control (AIMC) is proposed and applied on autonomous landing control system in this paper. Controllers are designed based on the decoupled and linearized models of a sample UAV. Estimation of process model is carried out to enhance system robustness, and filter parameter adjustment is proposed to achieve a good dynamic performance. Control effects are compared and analyzed between IMC and AIMC in different wind conditions which demonstrate that AIMC has better performances than IMC. At last, Monte Carlo simulations prove the system stability.

Document type: Article

Research on AE Signal Propagation in Helicopter Structural Elements

Scipedia content — Tue, 23 Mar 2021 05:19:01 +0100

"jats:p" The paper contains results of experimental research carried out helicopter bench. In order to create an attenuation chart for AE signal amplitude in helicopter fuselage, a number of experiments were performed on the frame and stringers, inside the fuselage. Later helicopter test bench was used to develop defect localization methodology of helicopter structure fatigue damage technical diagnostics. Analysing helicopter structural defects for different helicopters types it is concluded that the joint elements of helicopter tail boom are still exposed to fatigue crack formation. AE method shows highly effective results predicting fracture of helicopter joint elements.

Document type: Article

Evaluation of quality public transport criteria in terms of passenger satisfaction

Scipedia content — Tue, 23 Mar 2021 05:14:35 +0100

"jats:p"This article presents a detailed description and explanation of the methodology for evaluation of quality public transport criteria in terms of passenger satisfaction. In 2011-2014 this method was applied in an assessment of passenger satisfaction with the urban public transport system in Ostrava. In order to assess passengers’ satisfaction, traffic survey has been chosen utilizing questionnaire and student inquirers. The results achieved by application of the method have been processed to evaluate time accessibility criteria of a public transport system. Time accessibility criteria group (accessibility of stops, waiting for a connection and transferability in the public transport network) evaluates physical and psychological aspects of the passenger during his arrival at the station, while leaving the station, in the course of waiting for a connection and during the transfer. The time accessibility criteria are considered the most significant criteria that impact a passenger’s decision to utilise public transport options.

Document type: Article

Estimation of the Parameters Affecting the Water Pipelines on the Mining Terrains with A Use of An Adaptive Fuzzy System

Scipedia content — Tue, 23 Mar 2021 05:07:49 +0100

"jats:p" The research presented in this paper is basically focused on two objectives. Firstly, the selection of parameters affecting the water supply network damage. The causes of failures were selected from a population of tens of breakdown cases and then classified in view of their importance. Secondly, attention was paid to the selection of the most suitable linguistic model which could be commonly used for selecting factors which generate failures. Finally a Mamdani-based model could be worked out as a system possessing best generalization qualities. This model can create bases for an adaptative decision system which can show the type of water supply-sewage network, depending on continuous surface strains due to the mining activity.

Document type: Article

A Survey on Urban Traffic Management System Using Wireless Sensor Networks

Scipedia content — Tue, 23 Mar 2021 03:53:26 +0100

Nowadays, the number of vehicles has increased exponentially, but the bedrock capacities of roads and transportation systems have not developed in an equivalent way to efficiently cope with the number of vehicles traveling on them. Due to this, road jamming and traffic correlated pollution have increased with the associated adverse societal and financial effect on different markets worldwide. A static control system may block emergency vehicles due to traffic jams. Wireless Sensor networks (WSNs) have gained increasing attention in traffic detection and avoiding road congestion. WSNs are very trendy due to their faster transfer of information, easy installation, less maintenance, compactness and for being less expensive compared to other network options. There has been significant research on Traffic Management Systems using WSNs to avoid congestion, ensure priority for emergency vehicles and cut the Average Waiting Time (AWT) of vehicles at intersections. In recent decades, researchers have started to monitor real-time traffic using WSNs, RFIDs, ZigBee, VANETs, Bluetooth devices, cameras and infrared signals. This paper presents a survey of current urban traffic management schemes for priority-based signalling, and reducing congestion and the AWT of vehicles. The main objective of this survey is to provide a taxonomy of different traffic management schemes used for avoiding congestion. Existing urban traffic management schemes for the avoidance of congestion and providing priority to emergency vehicles are considered and set the foundation for further research.

Document type: Article

Mixed High-Speed, Conventional and Metro Central Rail Stations as Places to Work: The Case Study of Naples

Scipedia content — Tue, 23 Mar 2021 03:38:56 +0100

International audience; Today, rail stations tend to be considered as nodes but also as places within an area. In this respect, different types of shops and services can be present in rail stations. High Speed Rail services tend to increase the importance of the train station as a place. Our aim is to show that in some cases, some firms extend the role of the station as a place by using high speed train stations to provide temporary offices inside them. Thus the role of the station as a place is transformed in a place to work for mobile workers, a kind of third-place. This is the case of Regus, which is the world's leading provider of flexible workspaces all over the world, supporting over 1 million customers everyday. The objective of this contribution is to identify the characteristics of the clients of the temporary Regus offices in the Naples HSR station and the role of HSR in this context. For this purpose, a recent survey has been employed, interviewing clients using Regus offices. Data concerning the clients have been collected, such as socio-economic characteristics, transport mode chosen to reach Naples and the Regus services used.

Document type: Article

A Novel Surrogate Safety Indicator Based on Constant Initial Acceleration and Reaction Time Assumption

Scipedia content — Tue, 23 Mar 2021 03:28:51 +0100

The development of surrogate safety measures has drawn significant research interest in the field of traffic safety analysis. Innovative data sources such as video-based traffic surveillance systems have made it possible to collect large amounts of microscopic traffic data. By deriving traffic safety indicators such as the Deceleration Rate to Avoid a Crash (DRAC) statements concerning traffic safety over a determined road section can be made. This work presents the derivation of a novel surrogate safety indicator based on a Constant Initial Acceleration and reaction time assumption which considers the interaction between vehicles and describes the traffic safety of a road section. The evaluation is based on a video-based microscopic traffic data collection. To examine the efficiency, the new developed indicator is compared to the original Deceleration Rate to Avoid a Crash (DRAC) and the modified indicator (MDRAC) which includes the reaction time. The results showed that the new indicator is more sensitive in detecting critical situations than the other indicators and in addition describes the conflict situations more realistically.

Document type: Article

Three Extensions of Tong and Richardson’s Algorithm for Finding the Optimal Path in Schedule-Based Railway Networks

Scipedia content — Tue, 23 Mar 2021 03:16:57 +0100

High-speed railways have been developing quickly in recent years and have become a main travel mode between cities in many countries, especially China. Studying passengers’ travel choices on high-speed railway networks can aid the design of efficient operations and schedule plans. The Tong and Richardson algorithm that is used in this model offers a promising method for finding the optimal path in a schedule-based transit network. However, three aspects of this algorithm limit its application to high-speed railway networks. First, these networks have more complicated common line problems than other transit networks. Without a proper treatment, the optimal paths cannot be found. Second, nonadditive fares are important factors in considering travel choices. Incorporating these factors increases the searching time; improvement in this area is desirable. Third, as high-speed railways have low-frequency running patterns, their passengers may prefer to wait at home or at the office instead of at the station. Thus, consideration of a waiting penalty is needed. This paper suggests three extensions to improve the treatments of these three aspects, and three examples are presented to illustrate the applications of these extensions. The improved algorithm can also be used for other transit systems.

Document type: Article

A Method for Traffic Congestion Clustering Judgment Based on Grey Relational Analysis

Scipedia content — Tue, 23 Mar 2021 02:43:29 +0100

Traffic congestion clustering judgment is a fundamental problem in the study of traffic jam warning. However, it is not satisfactory to judge traffic congestion degrees using only vehicle speed. In this paper, we collect traffic flow information with three properties (traffic flow velocity, traffic flow density and traffic volume) of urban trunk roads, which is used to judge the traffic congestion degree. We first define a grey relational clustering model by leveraging grey relational analysis and rough set theory to mine relationships of multidimensional-attribute information. Then, we propose a grey relational membership degree rank clustering algorithm (GMRC) to discriminant clustering priority and further analyze the urban traffic congestion degree. Our experimental results show that the average accuracy of the GMRC algorithm is 24.9% greater than that of the K-means algorithm and 30.8% greater than that of the Fuzzy C-Means (FCM) algorithm. Furthermore, we find that our method can be more conducive to dynamic traffic warnings.

Document type: Article

Analyzing Traffic Crash Severity in Work Zones under Different Light Conditions

Scipedia content — Tue, 23 Mar 2021 02:35:56 +0100

Previous studies have investigated various factors that contribute to the severity of work zone crashes. However, little has been done on the specific effects of light conditions. Using the data from the Enhanced Tennessee Roadway Information Management System (E-TRIMS), crashes that occurred in the Tennessee work zones during 2003–2015 are categorized into three light conditions: daylight, dark-lighted, and dark-not-lighted. One commonly used decision tree method—Classification and Regression Trees (CART)—is adopted to investigate the factors contributing to crash severity in highway work zones under these light conditions. The outcomes from the three decision trees with differing light conditions show significant differences in the ranking and importance of the factors considered in the study, thereby indicating the necessity of examining traffic crashes according to light conditions. By separately considering the crash characteristics under different light conditions, some new findings are obtained from this study. The study shows that an increase in the number of lanes increases the crash severity level in work zones during the day while decreasing the severity at night. Similarly, drugs and alcohol are found to increase the severity level significantly under the dark-not-lighted condition, while they have a limited influence under daylight and dark-lighted conditions.

Document type: Article

Energy efficiency improvements in air traffic: The case of Airbus A320 in Spain

Scipedia content — Tue, 23 Mar 2021 02:19:02 +0100

Structural improvements in aircraft design, seeking to improve energy efficiency, can significantly reduce greenhouse gas emissions (GHG) by reducing reduced fuel consumption. This research reviews improvements with the introduction of a structural component known as "winglet;" these are positioned at the top of the aircraft wing, and increased Airbus Group A320 sales. Data used are taken from air traffic in Spain for the 2010–2014 period with projections being made for 2020. The results show that winglets reduce CO2 equivalent emissions associated with Spain's air transport for the 2015–2020 period between 66.29 and 59.56 Gg. depending on the scenario considered in 2020. Junta de Andalucía proyecto SEJ-132 Fundación Roger Torné, Universidad de Sevilla, Cátedra de Economía de la Energía y del Medio Ambiente 1394/0103 Ministerio de Economía y Competitividad de España ECO2014-56399-R Universidad Autónoma de Chile

Document type: Article

Stochastic Dynamic Traffic Assignment Model under Emergent Incidents

Scipedia content — Tue, 23 Mar 2021 01:48:36 +0100

Urban emergent incidents affect transportation operation and result in the rapid spread of traffic congestion in network, so it's necessary to analyze the dynamic changes of traffic flow distribution under emergent incidents. Therefore, model and algorithm for the dynamic traffic assignment problem under emergent incidents have been highly concerned by government and scholars. This paper proposes a stochastic dynamic traffic assignment (SDTA) model based user optimum considering the loss of node capacity and change of network structure under traffic and environment emergencies. The Nested Logit model is used to describe the departure time and path choice. Then, the variational inequality formulation is proposed and discrete dynamic network loading algorithm is designed and validated by a numerical example. The results show that the model and algorithm can be used to express the development trend of actual dynamic network under emergency.

Document type: Article

A Hybrid Method for Short-Term Traffic Congestion Forecasting Using Genetic Algorithms and Cross Entropy

Scipedia content — Tue, 23 Mar 2021 00:35:52 +0100

This paper presents a method of optimizing the elements of a hierarchy of fuzzy-rule-based systems (FRBSs). It is a hybridization of a genetic algorithm (GA) and the cross-entropy (CE) method, which is here called GACE. It is used to predict congestion in a 9-km-long stretch of the I5 freeway in California, with time horizons of 5, 15, and 30 min. A comparative study of different levels of hybridization in GACE is made. These range from a pure GA to a pure CE, passing through different weights for each of the combined techniques. The results prove that GACE is more accurate than GA or CE alone for predicting short-term traffic congestion.

Document type: Article

Extraction Method of Driver’s Mental Component Based on Empirical Mode Decomposition and Approximate Entropy Statistic Characteristic in Vehicle Running State

Scipedia content — Tue, 23 Mar 2021 00:26:00 +0100

In the driver fatigue monitoring technology, the essence is to capture and analyze the driver behavior information, such as eyes, face, heart, and EEG activity during driving. However, ECG and EEG monitoring are limited by the installation electrodes and are not commercially available. The most common fatigue detection method is the analysis of driver behavior, that is, to determine whether the driver is tired by recording and analyzing the behavior characteristics of steering wheel and brake. The driver usually adjusts his or her actions based on the observed road conditions. Obviously the road path information is directly contained in the vehicle driving state; if you want to judge the driver’s driving behavior by vehicle driving status information, the first task is to remove the road information from the vehicle driving state data. Therefore, this paper proposes an effective intrinsic mode function selection method for the approximate entropy of empirical mode decomposition considering the characteristics of the frequency distribution of road and vehicle information and the unsteady and nonlinear characteristics of the driver closed-loop driving system in vehicle driving state data. The objective is to extract the effective component of the driving behavior information and to weaken the road information component. Finally the effectiveness of the proposed method is verified by simulating driving experiments.

Document type: Article

The Model to Assess the Implementation of Technical Conditions Defined in Annex IV of Marpol Convention 73/78: The Case of the Baltic Sea Port of Klaipeda

Scipedia content — Mon, 22 Mar 2021 23:52:51 +0100

"jats:p"Baltic Marine Environment Protection Commission members seeking to implement MARPOL 73/78 Annex IV amendments which recognize the Baltic Sea as special are, in which discharge of uncommitted sewage from passenger ships is forbidden, must ensure that ports are equipped with adequate reception facilities. To ensure implementation of amendments of Annex IV in port of Klaipeda, the analysis framework model was defined by authors. The model evaluates the readiness of the port to changes brought by the amendments of MARPOL Annex IV. The scientific problem comes with perception of adequacy. Resolution MEPC.200(62) amending MARPOL 73/78 Annex IV states, that port reception facilities must be adequate to the needs of passenger ships using them without causing undue delay. Concept of adequacy is not defined, therefore other guidelines explaining adequacy were used: EU directive 2000/59/EC and IMO resolution MEPC.83(44) Guidelines for ensuring adequacy of port reception facilities. Based on these sources, criteria that must be met to ensure adequacy were identified and tested in article: 1) reception facilities meet needs of ships normally using them; 2) discharge of sewage does to cause undue delay; 3) reception facilities does not provide disincentive to use them; 4) facilities are accessible; 5) facilities contribute to the improvement of the marine environment.

Document type: Article

Optimising local council's return on investment from annual pavement rehabilitation budgets through targeting of the average pavement condition index

Scipedia content — Mon, 22 Mar 2021 23:47:01 +0100

A high quality transportation system is necessary in a modern economy, and a road network is a common and significant, component of the system. Road systems have two major objectives: to enable the movement of passenger vehicles and the movement of freight vehicles at reasonable speeds. An important part of the transportation system and an expensive investment, a functional road network must meet both objectives to maintain an efficient economy. In Australia, the Department of Infrastructure and Regional Development reported that, in 2011/12, the total road length was approximately 900,000 km, and the total road expenditure was approximately $19 billion. Good policy requires that infrastructure investments provide a return on investment, thus warranting judicious management to ensure that it is maintained in a cost effective manner. Recent studies in Queensland, Australia, have identified differences between financial and engineering professionals in their understanding of infrastructure depreciation, condition deterioration, and future funding needs. Furthermore, the Queensland Asset Sustainability Ratio (ASR) requires clearer definitions to ensure that infrastructure remains meaningful to all users. This study proposes a separate sustainability index for road pavements (SIR) unlike the ASR that combines all type of assets. The justification is our ability to assess road condition, the high value of road assets, relative value to other infrastructure, and advanced knowledge of deterioration relative to other infrastructure. The SIR involves community consultation to target an average pavement condition index (PCI). This study also provides an alternative method to determine the optimal target PCI for a local government authority (LGA) that balances community expectations and funding levels, with a particular focus on return on investment (ROI) for the annual road reseal and rehabilitation budget.

Document type: Article

Optimal Container Routing in Liner Shipping Networks Considering Repacking 20 ft Containers into 40 ft Containers

Scipedia content — Mon, 22 Mar 2021 23:21:11 +0100

The volume of a 40 ft container is twice as large as that of a 20 ft container. However, the handling cost (loading, unloading, and transshipment) of a 40 ft container is much lower than twice the corresponding handling cost of two 20 ft containers. Enlightened by this observation, we propose a novel container routing with repacking problem in liner shipping, where two 20 ft containers can be repacked to a 40 ft container in order to reduce the handling cost. We develop a mixed-integer linear programming model that formulates the routing decisions and the repacking decisions in a holistic manner. An illustrative example is reported to demonstrate the applicability of the model. Results show that the benefit of repacking is the most significant when containers are transshipped several times.

Document type: Article

Critical analysis of laboratory measurements and monitoring system of water-pipe network corrosion-case study.

Scipedia content — Mon, 22 Mar 2021 22:57:00 +0100

Case study of corrosion failure of urban water supply system caused by environmental factors was presented. Nowadays corrosion monitoring of water distribution systems is an object of major concern. There is possibility of application broad range of techniques like gravimetric and electrochemical. Both kinds of techniques can be applied in laboratory and field conditions. In many cases researches limit the case analysis to measurements in laboratory conditions. Presented work contain critical analysis of results obtained in laboratory and field conditions based on corrosion monitoring of three pipelines systems failure in Krakow.

Document type: Article

Inductive Power Transfer Systems for Bus-Stop-Powered Electric Vehicles

Scipedia content — Mon, 22 Mar 2021 22:52:51 +0100

This study presents an inductive power transfer (IPT) system for electric vehicles (EVs) based on EE-shaped ferrite cores. The issues of the IPT system such as efficiency, air gap, displacement, dislocation, and motion are discussed. Furthermore, finite element analysis software is utilized to simulate the IPT system operated under large air gap conditions. Simulation and measurement results are presented to validate the performance of the proposed scheme and meet the requirements for bus-stop-powered EVs.

Document type: Article

Recognition and Reconstruction of Zebra Crossings on Roads from Mobile Laser Scanning Data

Scipedia content — Mon, 22 Mar 2021 22:09:07 +0100

Zebra crossings provide guidance and warning to pedestrians and drivers, thereby playing an important role in traffic safety management. Most previous studies have focused on detecting zebra stripes but have not provided full information about the areas, which is critical to both driver assistance systems and guide systems for blind individuals. This paper presents a stepwise procedure for recognizing and reconstructing zebra crossings using mobile laser scanning data. First, we propose adaptive thresholding based on road surface partitioning to reduce the impact of intensity unevenness and improve the accuracy of road marking extraction. Then, dispersion degree filtering is used to reduce the noise. Finally, zebra stripes are recognized according to the rectangular feature and fixed size, which is followed by area reconstruction according to arrangement patterns. We test our method on three datasets captured by an Optech Lynx mobile mapping system. The total recognition rate of 90.91% demonstrates the effectiveness of the method.

Document type: Article

Entropy Minimizing Curves with Application to Flight Path Design and Clustering

Scipedia content — Mon, 22 Mar 2021 22:07:40 +0100

International audience; Air traffic management (ATM) aims at providing companies with a safe and ideally optimal aircraft trajectory planning. Air traffic controllers act on flight paths in such a way that no pair of aircraft come closer than the regulatory separation norms. With the increase of traffic, it is expected thatthe system will reach its limits in a near future: a paradigm change in ATM is planned with the introduction of trajectory based operations. In this context, sets of well separated flight paths are computed in advance, tremendously reducing the number of unsafe situations that must be dealt with by controllers. Unfortunately, automated tools used to generate such plannings generally issue trajectories not complying with operational practices or even flight dynamics. In this paper, a mean of producing realistic air routes from the output of an automated trajectory design tool is investigated. For that purpose, the entropy of a system of curves is first defined and a mean of iteratively minimizing it is presented.The resulting curves form a route network that is suitable for use in a semi-automated ATM system with human in the loop. The tool introduced in this work is quite versatile and may be applied also to unsupervised classification of curves: an example is given for the french traffic.

Document type: Article

Measurement of the stressed state of welded joints in the NPP process components and circulation pipelines based on acoustoelasticity theory

Scipedia content — Mon, 22 Mar 2021 21:58:49 +0100

The paper presents the results of a theoretical justification and an experimental research for a method to measure the stressed state of welded joints in the nuclear power plant (NPP) process components and circulation pipelines based on acoustoelasticity theory, as well as for ways to implement them technically. Devices for measuring the stressed state of welded joints in the NPP process components and circulation pipelines based on acoustoelasticity theory allow online measurement of residual stresses along the weld height and detection of crack formation points. The use of such devices will enable early crack detection in welded joints for an increased safety of the NPP operation.

Document type: Article

Designs and Algorithms to Map Eye Tracking Data with Dynamic Multielement Moving Objects

Scipedia content — Mon, 22 Mar 2021 21:47:22 +0100

Design concepts and algorithms were developed to address the eye tracking analysis issues that arise when (1) participants interrogate dynamic multielement objects that can overlap on the display and (2) visual angle error of the eye trackers is incapable of providing exact eye fixation coordinates. These issues were addressed by (1) developing dynamic areas of interests (AOIs) in the form of either convex or rectangular shapes to represent the moving and shape-changing multielement objects, (2) introducing the concept of AOI gap tolerance (AGT) that controls the size of the AOIs to address the overlapping and visual angle error issues, and (3) finding a near optimal AGT value. The approach was tested in the context of air traffic control (ATC) operations where air traffic controller specialists (ATCSs) interrogated multiple moving aircraft on a radar display to detect and control the aircraft for the purpose of maintaining safe and expeditious air transportation. In addition, we show how eye tracking analysis results can differ based on how we define dynamic AOIs to determine eye fixations on moving objects. The results serve as a framework to more accurately analyze eye tracking data and to better support the analysis of human performance.

Document type: Article

Electric Vehicles in Logistics and Transportation: A Survey on Emerging Environmental, Strategic, and Operational Challenges

Scipedia content — Mon, 22 Mar 2021 21:29:25 +0100

Current logistics and transportation (L&T) systems include heterogeneous fleets consisting of common internal combustion engine vehicles as well as other types of vehicles using ?green? technologies, e.g., plug-in hybrid electric vehicles and electric vehicles (EVs). However, the incorporation of EVs in L&T activities also raise some additional challenges from the strategic, planning, and operational perspectives. For instance, smart cities are required to provide recharge stations for electric-based vehicles, meaning that investment decisions need to be made about the number, location, and capacity of these stations. Similarly, the limited driving-range capabilities of EVs, which are restricted by the amount of electricity stored in their batteries, impose non-trivial additional constraints when designing efficient distribution routes. Accordingly, this paper identifies and reviews several open research challenges related to the introduction of EVs in L&T activities, including: (a) environmental-related issues; and (b) strategic, planning and operational issues associated with ?standard? EVs and with hydrogen-based EVs. The paper also analyzes how the introduction of EVs in L&T systems generates new variants of the well-known Vehicle Routing Problem, one of the most studied optimization problems in the L&T field, and proposes the use of metaheuristics and simheuristics as the most efficient way to deal with these complex optimization problems. Fil: Juan, Angel Alejandro. Universitat Oberta de Catalunya; España Fil: Mendez, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Faulin, Javier. Universidad de Navarra; España Fil: de Armas, Jesica. Universitat Oberta de Catalunya; España Fil: Grasman, Scott. Rochester Institute of Technology; Estados Unido

Document type: Article

Decision Tree-Based Maneuver Prediction for Driver Rear-End Risk-Avoidance Behaviors in Cut-In Scenarios

Scipedia content — Mon, 22 Mar 2021 21:21:45 +0100

Predicting driver rear-end risk-avoidance maneuvers in cut-in scenarios, especially dangerous precrash scenarios, benefits the customization of automatic driving, particularly automatic steering. This paper studies driver rear-end risk-avoidance behaviors in cut-in scenarios on a straight three-lane highway. Data from 24 participants in 1326 valid trials were collected using a motion-based driving simulator. An Eysenck Personality Questionnaire (revised for Chinese participants) was used to obtain the personality traits of the participants. Based on a statistical analysis, the candidate features used in the driver maneuver prediction were determined as a combination of objective risk indicators and driver characteristics. A decision tree-based model was constructed for maneuver prediction in cut-in scenarios. The prediction accuracy of the extracted classification rules was 79.2% for the training data set and 80.3% for the test data set. The most powerful predictive variables were extracted, and their effects on maneuver decisions were analyzed. The results show that driver characteristics strongly influence the prediction of maneuver decisions.

Document type: Article

Optimal Corridor Selection for a Road Space Management Strategy: Methodology and Tool

Scipedia content — Mon, 22 Mar 2021 21:04:55 +0100

Nationwide, there is a growing realization that there are valuable benefits to using the existing roadway facilities to their full potential rather than expanding capacity in a traditional way. Currently, state DOTs are looking for cost-effective transportation solutions to mitigate the growing congestion and increasing funding gaps. Innovative road space management strategies like narrowing of multiple lanes (three or more) and shoulder width to add a lane enhance the utilization while eliminating the costs associated with constructing new lanes. Although this strategy (among many) generally leads to better mobility, identifying optimal corridors is a challenge and may affect the benefits. Further, there is a likelihood that added capacity may provide localized benefits, at the expense of system level performance measures (travel time and crashes) because of the relocation of traffic operational bottlenecks. This paper develops a novel transportation programming and investment decision method to identify optimal corridors for adding capacity in the network by leveraging lane widths. The methodology explicitly takes into consideration the system level benefits and safety. The programming compares two conflicting objectives of system travel time and safety benefits to find an optimal solution.

Document type: Article

The Roller-Ground Dynamic Interaction in The Compaction Process Through Vibrations for Road Construction

Scipedia content — Mon, 22 Mar 2021 21:01:51 +0100

"jats:p" The natural soil used in filling the embankment of the road communications is characterized by the following factors: humidity, porosity, toughness. For certain factor values that describe the soil state is distinguished a certain soil behavior under the influence of the external forces applied through static or dynamic mechanical means."/jats:p" "jats:p"In this study are presented the numeric simulation results of the soil-compactor interaction based on the complex and nonlinear rheological model proposed by the author in the result of the elaborated doctorate thesis, that follows the real soil characteristics (elastic, dissipative and plastic) on those of the compaction equipment (with a single vibrating roll). The model was harmonised and granted in accordance with the results obtained from the processing of the experimental data. For the simulation model was used the specialized software package Matlab (Simulink, SimMechanics). The obtained results revealed the real behavior of the equipment and its action on the compacted soil.

Document type: Article

Implementation of Satellite Techniques in the Air Transport

Scipedia content — Mon, 22 Mar 2021 20:58:06 +0100

"jats:p" The article shows process of the implementation satellite systems in Polish aviation which contributed to accomplishment Performance-Based Navigation (PBN) concept. Since 1991 authors have introduced Satellite Navigation Equipment in Polish Air Forces. The studies and researches provide to the Polish Air Force alternative approaches, modernize their navigation and landing systems and achieve compatibility with systems of the North Atlantic Treaty Organization (NATO) and International Civil Aviation Organization (ICAO). Acquired experience, conducted military tests and obtained results enabled to take up work scientifically - research in the environment of the civil aviation. Therefore in 2008 there has been launched cooperation with Polish Air Navigation Services Agency (PANSA). Thanks to cooperation, there have been compiled and fulfilled three fundamental international projects: EGNOS APV MIELEC (EGNOS Introduction in European Eastern Region - APV Mielec), HEDGE (Helicopters Deploy GNSS in Europe), SHERPA (Support ad-Hoc to Eastern Region Pre-operational in GNSS). The successful completion of these projects enabled implementation 21 procedures of the RNAV GNSS final approach at Polish airports, contributing to the implementation of PBN in Poland as well as ICAO resolution A37-11. Results of conducted research which served for the implementation of satellite techniques in the air transport constitute the meaning of this material.

Document type: Article

How to make modal shift from road to rail possible in the European transport market, as aspired to in the EU Transport White Paper 2011

Scipedia content — Mon, 22 Mar 2021 20:55:27 +0100

The total demand for freight transport in Europe has increased significantly in recent decades, but most of it has been handled by road transport. To fulfil the modal shift targets set in the EU White Paper 2011, it will be necessary to double rail’s market share from today’s 18 %, by 2050. Translating this into reality means rail will have to handle 3 to 4 times the cargo volume it does today. With this in mind, the paper develops a vision of an efficient rail freight system in 2050. To achieve the above objective, the research applies literature survey and group discussion methodology and applying a system approach. Keeping on board the EU Transport White Paper 2011 modal shift targets, as well as future freight demand and customer requirements, the current research attempts to answer the following three critical questions: The authors find that the service quality can be improved by better planning, application of appropriate ICT-systems and adoption of an integrated supply chain approach. A more customer-orientated service can also be achieved by further deregulation of rail. There is also an urgent need for a faster implementation of Rail Freight Corridors (RFC). As well as liner trains, future rail freight services should be offering end-point trains, with semi/ fully automated loading/unloading equipment in hub-terminals, as well as terminals at sidings to improve the availability of intermodal operation. To offer a competitive price and reliable service, a reduction in operating costs will be vital by implementing a number of measures, including operation of heavier and longer trains, wider loading gauge, higher average speed, and better utilisation of wagon space and all assets. This will bring increased capacity, as well as better timetable planning, signalling systems and infrastructure improvements.

Document type: Article

A Least-Square Model to Estimate Historical Percentages of Itinerant General Aviation Operations by Aircraft Types and Flight Rules at an Airport

Scipedia content — Mon, 22 Mar 2021 20:46:31 +0100

Historical airport-level General Aviation (GA) activity plays an important role in airport managerial and operational decision-making processes. We developed a model to estimate historical percentages of itinerant GA operations by four aircraft types and two flight rules. The model is formulated as a least-square optimization model and can be applied to both towered and nontowered airports. We applied the model to airports in the Terminal Area Forecast and compared model estimates with the observed statistics. This study provides a method that could be used in the decision-making processes that require detailed historical GA operations.

Document type: Article

Air Transport versus High-Speed Rail: An Overview and Research Agenda

Scipedia content — Mon, 22 Mar 2021 20:43:04 +0100

The development of high-speed rail (HSR) services throughout the last decades has gradually blurred the concept of competition and cooperation with air transportation. There is a wide range of studies on this subject, with a particular focus on single lines or smaller regions. This article synthesizes and discusses recently published studies in this area, while aiming to identify commonalities and deviations among different regions throughout the world, covering services from Europe, Asia, and North America. Our meta-analysis reveals that the literature is highly controversial and the results vary substantially from one region to another, and a generalization is difficult, given route-specific characteristics, such as demand distribution, network structure, and evolution of transportation modes. As a major contribution, we propose a list of five challenges as a future research agenda on HSR/air transport competition and cooperation. Among others, we see a need for the construction of an open-source dataset for large-scale multimodal transport systems, the comprehensive assessment of new emerging transport modes, and also taking into account the resilience of multimodal transport systems under disruption.

Document type: Article

Location Design of Electric Vehicle Charging Facilities: A Path-Distance Constrained Stochastic User Equilibrium Approach

Scipedia content — Mon, 22 Mar 2021 20:10:57 +0100

Location of public charging stations, range limit, and long battery-charging time inevitably affect drivers’ path choice behavior and equilibrium flows of battery electric vehicles (BEVs) in a transportation network. This study investigates the effect of the location of BEVs public charging facilities on a network with mixed conventional gasoline vehicles (GVs) and BEVs. These two types of vehicles are distinguished from each other in terms of travel cost composition and distance limit. A bilevel model is developed to address this problem. In the upper level, the objective is to maximize coverage of BEV flows by locating a given number of charging stations on road segments considering budget constraints. A mixed-integer nonlinear program is proposed to formulate this model. A simple equilibrium-based heuristic algorithm is developed to obtain the solution. Finally, two numerical tests are presented to demonstrate applicability of the proposed model and feasibility and effectiveness of the solution algorithm. The results demonstrate that the equilibrium traffic flows are affected by charging speed, range limit, and charging facilities’ utility and that BEV drivers incline to choose the route with charging stations and less charging time.

Document type: Article

When It Comes to Container Port Efficiency, Are All Developing Regions Equal?

Scipedia content — Mon, 22 Mar 2021 20:10:12 +0100

This paper develops a port productivity and efficiency analysis of all developing regions between 2000 and 2010, using both parametric and nonparametric approaches. From a unique dataset -our sample covers 70 developing countries, 203 ports, and 1,750 data points-, we carry out an analysis of the evolution and drivers of productivity and efficiency changes across developing regions. We show that productivity growth rates between 2000 and 2010 vary significantly and that this heterogeneity is explained by pure efficiency changes rather than scale efficiency of technological changes. Therefore, we carry out a detailed efficiency analysis to determine the drivers of port efficiency. Time series results show an upward trend for port efficiency in developing regions, as it increased from 47 percent in 2000 to 57 percent in 2010. Our analysis indicates that private sector participation, the reduction of corruption in the public sector and improvements in liner connectivity and the existence of multimodal links increase the level of port efficiency in developing regions.

Document type: Article

Automatic Traffic Data Collection under Varying Lighting and Temperature Conditions in Multimodal Environments: Thermal versus Visible Spectrum Video-Based Systems

Scipedia content — Mon, 22 Mar 2021 19:44:35 +0100

Vision-based monitoring systems using visible spectrum (regular) video cameras can complement or substitute conventional sensors and provide rich positional and classification data. Although new camera technologies, including thermal video sensors, may improve the performance of digital video-based sensors, their performance under various conditions has rarely been evaluated at multimodal facilities. The purpose of this research is to integrate existing computer vision methods for automated data collection and evaluate the detection, classification, and speed measurement performance of thermal video sensors under varying lighting and temperature conditions. Thermal and regular video data was collected simultaneously under different conditions across multiple sites. Although the regular video sensor narrowly outperformed the thermal sensor during daytime, the performance of the thermal sensor is significantly better for low visibility and shadow conditions, particularly for pedestrians and cyclists. Retraining the algorithm on thermal data yielded an improvement in the global accuracy of 48%. Thermal speed measurements were consistently more accurate than for the regular video at daytime and nighttime. Thermal video is insensitive to lighting interference and pavement temperature, solves issues associated with visible light cameras for traffic data collection, and offers other benefits such as privacy, insensitivity to glare, storage space, and lower processing requirements.

Document type: Article

Gross polluters for food shopping travel: an activity-based typology

Scipedia content — Mon, 22 Mar 2021 19:40:47 +0100

To address the failure of sustainable transport policies to bring about significant change, researchers have proposed to ‘tame the few’, targeting the minority sectors of the population responsible for a disproportionate amount of emissions. At the same time, activity- and practice-based approaches are increasingly proposed as the way forward for transport and energy research. In this article, we develop an approach inspired by both developments, by focusing on the car- and carbon-intensive food shopping practices of the 20% of households with the longest car travel distance as recorded in the National Travel Survey of Great Britain (NTS 2002-2010) for this activity. We present a four-cluster typology of gross polluters, highlighting the crucial role of frequency and the existence of a small but growing group of low-income, older households with ‘Shopping intensive’ travel patterns. These results suggest that, while the households with the worst climate impact have a distinct socio-demographic profile, broader sections of the population are recruited into gross polluting patterns of food shopping travel. Also, while built environment policies remain key, significantly reducing transport emissions in this area requires a broader approach, taking into account the relationships between food shopping and eating practices.

Document type: Article

Robust Evaluation for Transportation Network Capacity under Demand Uncertainty

Scipedia content — Mon, 22 Mar 2021 19:37:21 +0100

As more and more cities in worldwide are facing the problems of traffic jam, governments have been concerned about how to design transportation networks with adequate capacity to accommodate travel demands. To evaluate the capacity of a transportation system, the prescribed origin and destination (O-D) matrix for existing travel demand has been noticed to have a significant effect on the results of network capacity models. However, the exact data of the existing O-D demand are usually hard to be obtained in practice. Considering the fluctuation of the real travel demand in transportation networks, the existing travel demand is represented as uncertain parameters which are defined within a bounded set. Thus, a robust reserve network capacity (RRNC) model using min–max optimization is formulated based on the demand uncertainty. An effective heuristic approach utilizing cutting plane method and sensitivity analysis is proposed for the solution of the RRNC problem. Computational experiments and simulations are implemented to demonstrate the validity and performance of the proposed robust model. According to simulation experiments, it is showed that the link flow pattern from the robust solutions to network capacity problems can reveal the probability of high congestion for each link.

Document type: Article

Tagging in Volunteered Geographic Information: An Analysis of Tagging Practices for Cities and Urban Regions in OpenStreetMap

Scipedia content — Mon, 22 Mar 2021 19:36:50 +0100

In Volunteered Geographic Information (VGI) projects, the tagging or annotation of objects is usually performed in a flexible and non-constrained manner. Contributors to a VGI project are normally free to choose whatever tags they feel are appropriate to annotate or describe a particular geographic object or place. In OpenStreetMap (OSM), the Map Features part of the OSM Wiki serves as the de-facto rulebook or ontology for the annotation of features in OSM. Within Map Features, suggestions and guidance on what combinations of tags to use for certain geographic objects are outlined. In this paper, we consider these suggestions and recommendations and analyse the OSM database for 40 cities around the world to ascertain if contributors to OSM in these urban areas are using this guidance in their tagging practices. Overall, we find that compliance with the suggestions and guidance in Map Features is generally average or poor. This leads us to conclude that contributors in these areas do not always tag features with the same level of annotation. Our paper also confirms anecdotal evidence that OSM Map Features is less influential in how OSM contributors tag objects.

Document type: Article

Introducing Weather Factor Modelling into Macro Traffic State Prediction

Scipedia content — Mon, 22 Mar 2021 19:35:23 +0100

Adverse weather has significant impacts on road conditions and traffic dynamics. It is observed that adverse weather as a set of exogenous factors lowers the free flow speed, shifts critical density, decreases flow capacity, and makes the freeway more prone to congestion. This paper proposes a weather factor model to be plugged into a macroscopic traffic prediction model, so that under bad weather traffic variables can be more accurately and reasonably estimated and predicted for traffic control use. To be specific, weather-specific fundamental diagrams are built by introducing weather factors to free flow speed, capacity, and critical density. The weather factors are modelled by selected weather measurements. Weather factor parameters are trained by recent historical weather and traffic data and then can be put into real-time macro traffic prediction and control. The traffic prediction model in the case study is METANET model, in which fundamental diagram parameters are one source of input. The weather-specific prediction error and conventional prediction error are compared. Real data collected by loop detectors on Whitemud Drive, Edmonton, Canada, is used for parameter calibration and prediction error evaluation. The results show that the proposed weather models reasonably improved the accuracy of macro traffic state prediction model compared to conventional model.

Document type: Article

Corrigendum to “Characteristic Analysis of Mixed Traffic Flow of Regular and Autonomous Vehicles Using Cellular Automata”

Scipedia content — Mon, 22 Mar 2021 19:22:57 +0100

Document type: Article

Combined application of multi-criteria optimization and life-cycle sustainability assessment for optimal distribution of alternative passenger cars in US

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

This research aims to advance the existing sustainability assessment framework for alternative passenger cars with a combination of life-cycle sustainability assessment and multi-criteria decision-making. To this end, sixteen macro-level sustainability impacts are evaluated for seven different vehicle types: internal combustion vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles with all-electric ranges of 16, 32, 48, and 64 km of electric powered drive, and battery electric vehicles. Additionally, two battery charging scenarios are considered in this analysis with respect to plug-in hybrid electric vehicles and battery electric vehicles; Scenario 1 is based on existing electric power infrastructure in the U.S., while Scenario 2 is an extreme scenario in which electricity to power battery electric vehicles and plug-in hybrid electric vehicles is generated entirely via solar charging stations. In this study, optimal vehicle distributions are calculated based on the environmental, social, and economic impacts of all vehicle types for each scenario. Various distributions are presented in accordance with the relative importance assigned to each indicator, with different weighting scenarios applied to account for variability in decision-makers' priorities, such as the assignment of higher weights to socio-economic indicators (e.g. maximizing employment) and lower weights to environmental indicators (e.g. minimizing greenhouse gas emissions). In a balanced weighting case (i.e. when environmental and socio-economic indicators have equal importance) under Scenario 1, hybrid electric vehicles have the largest fleet share, comprising 91% of the optimal U.S. passenger car fleet, while internal combustion vehicles dominate the optimal fleet with 99.5% of the optimal fleet share when only socio-economic indicators are given priority. On the other hand, in a balanced weighting case under Scenario 2, the optimal U.S. passenger car fleet consists entirely (100%) of plug-in hybrid electric vehicles with 16 km of all-electric range. In the majority of the considered weighting scenarios, battery electric vehicles were not given any share of the optimal vehicle fleet. The proposed framework can be used as a practical decision-making platform when deciding which vehicle type to promote given each vehicle type's respective environmental, social, and economic impacts. Considering that decision makers are often highly influenced by the “silo effect”, i.e. a lack of communication among different agencies and departments (national or international), the proposed framework provides a holistic system-based approach to minimize the silo effect and can enhance the efficiency of future inter/cross/trans-disciplinary works. Furthermore, the outcomes of this study can pave the way for advancement in the state-of-the-art and state-of-the-practice of current sustainability research.

Application of the TOPSIS and intuitionistic fuzzy set approaches for ranking the life cycle sustainability performance of alternative vehicle technologies

Scipedia content — Tue, 16 Feb 2021 13:43:26 +0100

This research involves two novel elements to advance the body of knowledge in existing sustainability assessment frameworks for alternative vehicle technologies. First, we developed an input–output based hybrid life cycle sustainability assessment model using several macro-level social, economic, and environmental indicators, taking into consideration the manufacturing of vehicles and batteries, operation, and end-of-life phases. Second, the results of a hybrid life cycle sustainability assessment for different conventional and alternative vehicles technologies (internal combustion electric vehicles, hybrid electric vehicles, plug-in-hybrid electric vehicles, and battery electric vehicles) are incorporated into the Technique for Order-Preference by Similarity to Ideal Solution and Intuitionistic Fuzzy Sets. Two policy scenarios are considered in this analysis, with Scenario 1 being based on existing electric power infrastructure in the U.S. with no additional infrastructure requirements, while Scenario 2 is an extreme scenario in which the electricity to power electric vehicles is generated exclusively via solar charging stations. The Intuitionistic Fuzzy Multi-Criteria Decision Making and Technique for Order Preference by Similarity to Ideal Solution methods are then utilized to rank the life cycle sustainability performance of alternative passenger vehicles. Furthermore, since expert judgments play an important role in determining the relative performance of alternative vehicle technologies, a sustainability triangle analysis is also presented to show how the weighting applied to each dimension affects the selection of different alternatives. The results indicate that hybrid and plug-in hybrid electric vehicles are the best alternatives for both Scenarios 1 and 2 when all of the indicators are considered. On the other hand, the ranking of vehicles changes significantly when each of the environmental, economic, and social indicators are evaluated individually. This proposed method can be a useful decision making platform for decision-makers to develop more effective policies and guide the offering of incentives to the right domains for sustainable transportation.

Travel Demand Management (TDM) case study for social behavioral change towards sustainable urban transportation in Istanbul

Scipedia content — Tue, 16 Feb 2021 13:37:34 +0100

In order to realize sustainable cities, it is vital to achieve and maintain social behavioral change for shifting our modes of mobility from inefficient, wasteful and motorized means to cleaner, greener, healthier and more economic means such as walking, cycling and public transportation in addition to smart use of land, intelligent transportation systems, and clean and green vehicles. This study is based on a critical review of literature in order to establish a framework of social behavioral change policies, particularly developed and tested for urban mobility and traffic congestion. First, various mega cities were compared on different sustainability indicators to better understand the case of Istanbul. Then, selected policy potentials, namely Travel Demand Management (TDM), were evaluated for Istanbul following a set of personal interview surveys aiming to reveal travel patterns of residents, their perceptions and attitudes on current transport system performance, and their opinions for possible TDM interventions in the future. We proposed a multiplicative model to process data from these surveys as inputs, which would then be used to determine travel demand. A simulation model was constructed using PTV-VISSIM tool and validated with current traffic congestion metrics obtained from field measurements in a selected district of Istanbul. Based on this validated simulation model, projections of traffic conditions in the future under different TDM scenarios were predicted with the help of determined TDM potentials obtained from the survey results. As a result of this study, it was revealed that the traffic congestion levels in Istanbul tend to become worse year by year under existing conditions, but it was also found that the TDM policies offer significant potential for reducing congestion, hence its consequent hazards, via increased use of sustainable mobility modes without the need for new infrastructure investments.

Integration of system dynamics approach toward deepening and broadening the life cycle sustainability assessment framework: a case for electric vehicles

Scipedia content — Tue, 16 Feb 2021 13:34:39 +0100

Quantitative life cycle sustainable assessment requires a complex and multidimensional understanding, which cannot be fully covered by the current portfolio of reductionist-oriented tools. Therefore, there is a dire need on a new generation of modeling tools and approaches that can quantitatively assess the economic, social, and environmental dimensions of sustainability in an integrated way. To this end, this research aims to present a practical and novel approach for (1) broadening the existing life cycle sustainability assessment (LCSA) framework by considering macrolevel environmental, economic, and social impacts (termed as the triple bottom line), simultaneously, (2) deepening the existing LCSA framework by capturing the complex dynamic relationships between social, environmental, and economic indicators through causal loop modeling, (3) understanding the dynamic complexity of transportation sustainability for the triple bottom line impacts of alternative vehicles, and finally (4) investigating the impacts of various vehicle-specific scenarios as a novel approach for selection of a macrolevel functional unit considering all of the complex interactions in the environmental, social, and economic aspects. To alleviate these research objectives, we presented a novel methodology to quantify macrolevel social, economic, and environmental impacts of passenger vehicles from an integrated system analysis perspective. An integrated dynamic LCSA model is utilized to analyze the environmental, economic, and social life cycle impact as well as life cycle cost of alternative vehicles in the USA. System dynamics modeling is developed to simulate the US passenger transportation system and its interactions with economy, the environment, and society. Analysis covers manufacturing and operation phase impacts of internal combustion vehicles (ICVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). In total, seven macrolevel indicators are selected; global warming potential, particulate matter formation, photochemical oxidant formation, vehicle ownership cost, contribution to gross domestic product, employment generation, and human health impacts. Additionally, contribution of vehicle choices to global atmospheric temperature rise and public welfare is investigated. BEVs are found to be a better alternative for most of sustainability impact categories. While some of the benefits such as contribution to employment and GDP, CO2 emission reduction potential of BEVs become greater toward 2050, other sustainability indicators including vehicle ownership cost and human health impacts of BEVs are higher than the other vehicle types on 2010s and 2020s. While the impact shares of manufacturing and operation phases are similar in the early years of 2010s, the contribution of manufacturing phase becomes higher as the vehicle performances increase toward 2050. Analysis results revealed that the US transportation sector, alone, cannot reduce the rapidly increasing atmospheric temperature and the negative impacts of the global climate change, even though the entire fleet is replaced with BEVs. Reducing the atmospheric climate change requires much more ambitious targets and international collaborative efforts. The use of different vehicle types has a small impact on public welfare, which is a function of income, education, and life expectancy indexes. The authors strongly recommend that the dynamic complex and mutual interactions between sustainability indicators should be considered for the future LCSA framework. This approach will be critical to deepen the existing LCSA framework and to go beyond the current LCSA understanding, which provide a snapshot analysis with an isolated view of all pillars of sustainability. Overall, this research is a first empirical study and an important attempt toward developing integrated and dynamic LCSA framework for sustainable transportation research.

Networks of fixed-cycle intersections

Scipedia content — Tue, 16 Feb 2021 13:33:44 +0100

We present an algorithmic method for analyzing networks of intersections with static signaling, with as primary example a line network that allows traffic flow over several intersections in one main direction. The method decomposes the network into separate intersections and treats each intersection in isolation using an extension of the fixed-cycle traffic-light (FCTL) queue. The network effects are modeled by matching the output process of one intersection with the input process of the next (downstream) intersection. This network analysis provides insight into wave phenomena due to vehicles experiencing progressive cascades of green lights and sheds light on platoon forming in case of imperfections. Our algorithm is shown to match results from extensive discrete-event simulations and can also be applied to more complex network structures.

Improved one-dimensional models for rapid emptying and filling of pipelines

Scipedia content — Tue, 16 Feb 2021 13:22:00 +0100

Improved one-dimensional (1D) models—compared to previous work by the authors—are proposed which are able to predict the velocity, length, and position of the liquid column in the rapid emptying and filling of a pipeline. The models include driving pressure and gravity, skin friction and local drag, and holdup at the tail and gas intrusion at the front of the liquid column. Analytical and numerical results are validated against each other, and against experimental data from a large-scale laboratory setup.

How can fuel cell vehicles bring a bright future for this dragon? Answer by multi-criteria decision making analysis

Scipedia content — Tue, 16 Feb 2021 13:20:37 +0100

Fuel Cell Vehicles (FCVs) has been introduced to the market around the world in recent years. As the largest automobile market of the world, China is also one of the potential FCVs market. However, a series of factors and barriers influence the willingness of China's customers to accept FCVs. By using Fishbone Diagram, field survey and workshop discussions, this paper proposes a group of factors that may affect customers' preferences on FCVs. Furthermore, Fuzzy AHP and Pareto Analysis are employed to prioritize these factors, and identify the critical ones. The results indicate that fuel availability, vehicle performance, and economic costs are the most important dimensions in affecting customers' attitude towards FCVs. More specifically, vehicle reliability and safety, purchasing cost, industry development, vehicle model and space contribute the most significance in customers' purchase decision. According to the results, some policy implications are proposed from the prospective of improving and demonstrating vehicle performance, government leading facility construction and operation, and costs reductions. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Security vulnerability assessment of gas pipelines using Discrete-time Bayesian network

Scipedia content — Tue, 16 Feb 2021 13:19:29 +0100

Security of chemical and oil & gas facilities became a pressing issue after the terrorist attacks of 9/11, due to relevant quantities of hazardous substances that may be present in these sites. Oil & gas pipelines, connecting such facilities, might be potential targets for intentional attacks. The majority of methods addressing pipeline security are mostly qualitative or semi-quantitative, based on expert judgment and thus potentially subjective. In the present study, an innovative security vulnerability assessment methodology is developed, based on Discrete-time Bayesian network (DTBN) technique to investigate the vulnerability of a hazardous facility (pipeline in this study) considering the performance of security countermeasures in place. The methodology is applied to an illustrative gas pipeline in order to rank order the pipeline segments based upon their criticality.

Modelling ICT Perceptions and Views of Urban Front-liners

Scipedia content — Tue, 16 Feb 2021 13:15:10 +0100

Information and Communication Technologies (ICT) have become important tools to promote an achieve a variety of public goals and policies. The growing importance of ICT in daily life, business activities and governance prompts the need to consider the role of ICT more explicitly in urban administrations and policies. What are the city-makers' expectations of ICT? And how do they assess the future implications of ICT for their city? An analysis of these questions is needed to provide us with a better understanding of the extent to which urban authorities are willing to invest in, and to adopt, ICT policy. This paper offers both a conceptual and an operational model that aims to map out the causes and implications of ICT perceptions and views of urban policy-makers and/or administrative officials (denoted as urban front-liners). This is followed by the presentation of an operational path model-i.e. a linear structural equations model (Lisrel). The model serves to describe and test the relationships between perceptions of the city, policy-makers' beliefs about ICT and the associated urban ICT policy. According to the model, respondents who perceive their city as having many urban functions (such as commercial centre, service centre, higher education centre) have more awareness of various ICT tools and are likely to consider a multiplicity of ICT measures as relevant to their city. Respondents who consider their city as having severe bottlenecks (such as traffic congestion, housing shortage) are less likely to think of ICT measures and ICT-related goals as relevant to their city, and nor do they think that the municipality impacts significantly on ICT in the city. Furthermore, respondents who perceive their city as suffering from many socioeconomic problems (unemployment, ageing population, industrial decline and so on) are likely to consider many ICT tools as relevant to their city, although they have a low awareness of the specific tools to be deployed. Finally, respondents who believe that ICT will significantly (and positively) affect the city and its administration also tend to believe that the municipality has a high municipal influence on ICT and consider many ICT initiatives as relevant to their city. © 2004 The Editors of Urban Studies.

Division of activities and tasks-challenges and efficient structures for market-based procurement of public transport services

Scipedia content — Tue, 16 Feb 2021 13:11:04 +0100

Assessment of cathodic protection by close interval survey incorporating the instant off potential method

Scipedia content — Tue, 16 Feb 2021 13:08:51 +0100

This paper reviews five field assessments of the cathodic protection of coated steel pipelines buried in soils of an average resistivity of 4300 Ω cm, performed using the close interval survey (CIS) technique and incorporating the instant off potential (IOP) method to measure any voltage drop. Multiple current sources were identified in the surveys, and simultaneous interruption of all the current sources was achieved using synchronised switches. The results presented here highlight the importance of incorporating the IOP method when performing CIS in order to quantify the voltage drop factor and thus improve the interpretation of potential measurements. Unexpected field situations encountered when performing the CIS technique are discussed and the practicality of using corrosion coupons is analysed.

The authors express their gratitude to Eng. C. K. Meier from Corrosion Control Inc., Rutledge, Ga, USA for the many discussions, and to CICYT, Spain (Project Nº DPI2011-26480) for financial support.

Peer Reviewed

A new statistical method of assigning vehicles to delivery areas for CO 2 emissions reduction

Scipedia content — Tue, 16 Feb 2021 13:06:45 +0100

Transportation CO2 emissions are expected to increase in the following decades, and thus, new and better alternatives to reduce emissions are needed. Road transport emissions are explained by different factors, such as the type of vehicle, delivery operation and driving style. Because different cities may have conditions that are characterized by diversity in landforms, congestion, driving styles, etc., the importance of assigning the proper vehicle to serve a particular region within the city provides alternatives to reduce CO2 emissions. In this article, we propose a new methodology that results in assigning trucks to deliver in areas such that the CO2 emissions are minimized. Our methodology clusters the delivery areas based on the performance of the vehicle fleet by using the k-means algorithm and Tukey’s method. The output is then used to define the optimal CO2 truck-area assignment. We illustrate the proposed approach for a parcel company that operates in Mexico City and demonstrate that it is a practical alternative to reduce transportation CO2 emissions by matching vehicle type with delivery areas.

A brief introduction to the bird strike numerical simulation

Scipedia content — Tue, 16 Feb 2021 13:05:34 +0100

Bird impacts can be extremely critical events for the air transport safety. Since aircraft structures have become more and more complex components, the numerical prediction of the damage onset and evolution induced by a bird impact has become a very challenging task. The aim of this work is to provide a brief overview of the numerical techniques adopted for the prediction of the bird impact phenomenon on a leading edge of a regional aircraft wing. Smooth Particle Hydrodynamics (SPH), Rigid and Lagrangian models have been investigated and the results have been compared and critically assessed.

Are technology myths stalling aviation climate policy?

Scipedia content — Tue, 16 Feb 2021 13:05:19 +0100

Emissions from aviation will continue to increase in the future, in contradiction of global climate policy objectives. Yet, airlines and airline organisations suggest that aviation will become climatically sustainable. This paper investigates this paradox by reviewing fuel-efficiency gains since the 1960s in comparison to aviation growth, and by linking these results to technology discourses, based on a two-tiered approach tracing technology-focused discourses over 20 years (1994-2013). Findings indicate that a wide range of solutions to growing emissions from aviation have been presented by industry, hyped in global media, and subsequently vanished to be replaced by new technology discourses. Redundant discourses often linger in the public domain, where they continue to be associated with industry aspirations of 'sustainable aviation' and 'zero-emission flight'. The paper highlights and discusses a number of technology discourses that constitute 'technology myths', and the role these 'myths' may be playing in the enduring but flawed promise of sustainable aviation. We conclude that technology myths require policy-makers to interpret and take into account technical uncertainty, which may result in inaction that continues to delay much needed progress in climate policy for aviation.

V2V protocols for traffic congestion discovery along routes of interest in VANETs: a quantitative study

Scipedia content — Tue, 16 Feb 2021 13:02:53 +0100

One of the most interesting and promising challenges for Intelligent Transportation Systems (ITSs) relates to the traffic congestion problem. Congestion is a relevant issue for transportation because it reduces the efficiency of infrastructure and increases travel time, air pollution, and fuel consumption. Nowadays, the most promising technology in support of ITSs is found in the domain of Vehicular Ad Hoc Networks (VANETs). In this paper, we propose three protocols that are able to transmit traffic information for routes of interest on VANETs without any Road Side Unit (RSU) support. The proposed protocols adopt strategies to improve the performance of packet routing based on the density and location of vehicles; moreover, they enable an interesting comparison of the performance achievable with either reactive or proactive approaches. The extensive performance results reported show how it is possible to limit the congestion monitoring overhead along Routes of Interest (ROIs), while maintaining a sufficiently high performance in terms of traffic reporting. This may be done by employing context-aware data delivery techniques that autonomously adapt to runtime conditions. Copyright © 2016 John Wiley & Sons, Ltd.

A regression model for terminal airspace delays

Scipedia content — Tue, 16 Feb 2021 13:02:12 +0100

WOS: 000415149800005

Air Traffic Management (ATM) research generally focuses on achieving a safer, more effective and economical air traffic system. The current airspace system has become increasingly strained as the demand for air travel has steadily grown. Innovative, proactive and multi-disciplinary approaches to research are needed to solve flight congestion and delays as a consequence of this rapid growth. As a result of this growth, air traffic flow becomes more complex, especially in Terminal Airspaces (TMA) where climb and descent manoeuvres of departing and arriving flights take place around airports. As air traffic demand exceeds the capacity in a TMA, the resultant congestion leads to delays that spread all over the system. Therefore, the reduction of delays is critical for airspace designers to increase customer satisfaction and the perception of service quality. Numerous studies have been conducted to reduce delays within TMAs. This research focuses on defining the causes of delays quantitatively through statistical analysis. The first step was to create a fast-time simulation model of sample airspace for collecting delay data. After building up this model using the SIMMOD fast-time ATM simulation tool, simulation experiments were run to produce various traffic scenarios and to generate traffic delay data. The number of airports, entry points, fixes and flight operations in airspace and the probability of wide-body aircraft were considered as independent variables. The correlations between the considered variables were analysed, and the total delay data was modelled using a linear regression model. The findings of regression model present a statistical approach for airspace designers and air traffic flow planners.

Anadolu University Scientific Research Projects Commission [1203F052]

This study was supported by Anadolu University Scientific Research Projects Commission under grant no: 1203F052.

The Human Element and Autonomous Ships

Scipedia content — Tue, 16 Feb 2021 13:01:12 +0100

The autonomous ship technology has become a “hot” topic in the discussion about more efficient, environmentally friendly and safer sea transportation solutions. The time is becoming mature for the introduction of commercially sensible solutions for unmanned and fully autonomous cargo and passenger ships. Safety will be the most interesting and important aspect in this development. The utilization of the autonomous ship technology will have many effects on the safety, both positive and negative. It has been announced that the goal is to make the safety of an unmanned ship better that the safety of a manned ship. However, it must be understood that the human element will still be present when fully unmanned ships are being used. The shore-based control of a ship contains new safety aspects and an interesting question will be the interaction of manned and unmanned ships in the same traffic area. The autonomous ship technology should therefore be taken into account on the training of seafarers. Also it should not be forgotten that every single control algorithm and rule of the internal decision making logic of the autonomously navigating ship has been designed and coded by a human software engineer. Thus the human element is present also in this point of the lifetime navigation system of the autonomous ship.

Inventory theory, mode choice and network structure in freight transport

Scipedia content — Tue, 16 Feb 2021 13:00:22 +0100

In passenger transport, hub-and-spoke networks allow the transportation of small passenger flows with competitive frequencies, in a way that direct line networks cannot. Equivalently, in freight transport, it can be expected that small shipper-receiver flows of high added value commodities transit through hub and spoke networks, while larger shipper-receiver flows of less expensive commodities are transported directly, without transhipment. The objective of this paper is first to present an analytical model, based on inventory theory, explaining how for a given commodity flow, the organisation of freight transport operations is closely related to the characteristics of the shipper-receiver relationship; second to assess empirically this model. Special emphasis is put on the number of transhipments in the transport operation, as an indication of organisation of the transport operations. The theoretical model is a simplified microeconomic model, built on principles of inventory theory. The empirical assessment of this model is based on the French shipment survey ECHO, which provides both the details of the transport operation and of the shipper-receiver relationships. With this database, we first provide a straightforward, graphical verification of the prediction of the theoretical model; secondly, we estimate it econometrically. © 2016, Editorial Board EJTIR. All rights reserved.

Finding effective pathways to sustainable mobility: bridging the science–policy gap

Scipedia content — Tue, 16 Feb 2021 12:59:57 +0100

This overview paper examines three areas crucial to understanding why, despite clear scientific evidence for the growing environmental impacts of tourism transport, there is large-scale inertia in structural transitions and a lack of political will to enact meaningful sustainable mobility policies. These include the importance of addressing socio-technical factors, barriers posed by “technology myths” and the need to overcome “transport taboos” in policy-making. The paper seeks pathways to sustainable mobility by bridging the science–policy gap between academic research and researchers, and policy-makers and practitioners. It introduces key papers presented at the Freiburg 2014 workshop, covering the case for researcher engagement using advocacy and participatory approaches, the role of universities in creating their own social mobility policies, the power of social mechanisms encouraging long-haul travel, issues in consumer responsibility development, industry self-regulation and the operation of realpolitik decision-making and implementation inside formal and informal destination-based mobility partnerships. Overall, the paper argues that governments and the tourism and transport industries must take a more cautious approach to the technological optimism that fosters policy inertia, and that policy-makers must take a more open approach to implementing sustainable transport policies. A research agenda for desirable transport futures is suggested.

Spatial planning for fisheries in the Northern Adriatic: Working toward viable and sustainable fishing

Scipedia content — Tue, 16 Feb 2021 12:50:41 +0100

Given the great overfishing of the demersal resources in the Northern Adriatic Sea (geographical sub-area [GSA] 17), along with the fishing pressure in marine habitats, evidence strongly supports the need to evaluate appropriate management approaches. Several fishing activities operate simultaneously in"br/"the area, and the need to minimize conflicts among them is also a social concern. We applied a spatially and temporally explicit fish and fisheries model to assess the impact of a suite of spatial plans suggested by practitioners that could reduce the pressure on the four demersal stocks of high commercial interest in the GSA 17 and that could promote space sharing between mutually exclusive activities. We found that excluding trawlers from some areas has lowered the effective fishing effort, resulting in some economic losses but providing benefit to the set netters. Not every simulated fishing vessel is impacted in the same way because some fishing communities experienced different economic opportunities, particularly when a 6-nautical mile buffer zone from the coast was implemented in the vicinity of important fishing grounds. Along this buffer zone, the four stocks were only slightly benefiting from the protection of the area and from fewer discards. In contrast, assuming a change in the ability of the population to disperse led to a large effect: Some fish became accessible in the coastal waters, therefore increasing the landings for rangelimited fishers, but the discard rate of fish also increased, greatly impairing the long-term biomass levels. Our evaluation, however, confirmed that no effort is displaced onto vulnerable benthic habitats and to grounds not suitable for the continued operation of fishing. We conclude that the tested spatial management is helpful, but not sufficient to ensure sustainable fishing in the area, and therefore, additional management measures should be taken. Our test platform investigates the interaction between fish and fisheries at a fine geographical scale and simulates data for varying fishing methods and from different harbor communities in a unified framework. We contribute to the development of effective science-based inputs to facilitate policy improvement and better governance while evaluating trade-offs in fisheries management and marine spatial planning

When signal processing meets human factors : in the driver's seat

Scipedia content — Tue, 16 Feb 2021 12:46:04 +0100

This article provides an interdisciplinary perspective on driver monitoring systems by discussing state-of-the-art signal processing solutions in the context of road safety issues identified in human factors research. Recently, the human factors community has made significant progress in understanding driver behaviors and assessed the efficacy of various interventions for unsafe driving practices. In parallel, the signal processing community has had significant advancements in developing signal acquisition and processing methods for driver monitoring systems. This article aims to bridge these efforts and help initiate new collaborations across the two fields. Toward this end, we discuss how vehicle measures, facial/body expressions, and physiological signals can assist in improving driving safety through adaptive interactions with the driver, based on the driver's state and driving environment. Moreover, by highlighting the current human factors research in road safety, we provide insights for building feedback and mitigation technologies, which can act both in real time and postdrive. We provide insights into areas with great potential to improve driver monitoring systems, which have not yet been extensively studied in the literature, such as affect recognition and data fusion. Finally, a high-level discussion is given on the challenges and possible future directions for driver monitoring systems.

Unfamiliar fuel:How the UK public views the infrastructure required to supply hydrogen for road transport

Scipedia content — Tue, 16 Feb 2021 12:40:20 +0100

In 2007, under contract to the UK Department for Transport, we engaged with the public about the infrastructure to supply hydrogen for transport. We combined a quota-sample survey of 1003 across three disparate ‘travel-to-work areas’ in England with focus groups representative of them. We informed the groups ‘at arm's length’ through a purpose-made video, composed with advice from a hydrogen scientist and made by professional broadcasters. Participants saw benefits in hydrogen energy. None rejected it on safety grounds, though many discussed the risks. The costs were considered a problem. ‘The public’ was not of one mind. Regular car drivers were unwilling to reduce their car use. Bus users, cyclists and walkers often sought improvements in air quality. Motorists knew more than others about hydrogen energy. In discussion we seek psychological and socio-cultural explanations for these results. We conclude by drawing out implications for the future of hydrogen in transport.

The attitudes of shippers and forwarders

Scipedia content — Tue, 16 Feb 2021 12:37:17 +0100

The transport sector accounts for 25% of the global CO2 emissions. All firms in the transport industry share a responsibility for this environmental impact. This paper explores, as one of the first, the attitude of both shippers and forwarders, as the main purchasers of transport services, towards environmental sustainability in the sourcing of transport services. Based on a literature review we develop several hypotheses and test those through a survey among shippers and forwarders in the Netherlands. We conclude that shippers focus more on sustainability than forwarders, the size of shippers has a positive influence on the demand for transparency of the environmental performance, explicit sustainability targets have a positive influence on the demand for sustainable solutions and the vast majority of shippers and forwarders expect an increased importance of sustainable purchasing.

Aviation product lability insurance in US, UK, and Italian law systems

Scipedia content — Tue, 16 Feb 2021 12:34:43 +0100

The complexity of the insurance liability from defective aeronautical product and the high-risk level of the air transport sector imply a highly specialized insurance market. This market is characterized by principles common to the US, UK and Italian insurance practices. Th e market in which insurance companies operate is characterized by continuous operating improvements and technical innovations that have allowed a reduction of aviation accidents. However, we have seen that the technologies bring new vulnerabilities due to new devices, as well as by the increasing regulation of the sector. Th is led to the confi guration of further assumptions of liability and reimbursable damage. Europe is now facing a new challenge with the initiative of the Single European Sky (SES-SESAR) aiming to improve the integration and effi ciency of air traffi c management, step up the air navigation services and increase safety. Therefore, the insurance practice should be re-evaluated in the light of SES and the introduction of new technologies. Among the risk factors that the insurance market will have to take into account there is certainly the human factor, which is still a major cause of aeronautical accidents, including those due to product liability, at least with regard to the design and installation of aircraft components. Therefore, it will be interesting to examine whether the development of SES will contribute not only to prevent aircraft accidents but also to develop new safeguards to protect the aviation sector, including the insurance services, allowing insurers to offer competitive policies appropriate for the future technological changes.

The meeting of hydrogen and automotive: A review

Scipedia content — Tue, 16 Feb 2021 12:33:37 +0100

1st International Mediterranean Science and Engineering Congress (IMSEC)

WOS: 000412033800073

In this study, an overview has been presented a classification of the vehicles using hydrogen with different ways. The using of hydrogen in vehicles has been categorized into two main categories as designs in which hydrogen is burned and energy is generated by conversion to electricity. The designs of internal combustion vehicles with using hydrogen via burning, the designs of the fuel cell vehicles that using hydrogen by converting into electricity and their hybrid versions have been introduced. In the automotive industry, the structure and future advantages of hydrogen fuel cell electric vehicles have been handled in a separate title. Onboard storage, safety, the capital cost and operating cost of the different design of vehicles have been analyzed rigorously. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Design and analysis of a wireless power transfer system with alignment errors for electrical vehicle applications

Scipedia content — Tue, 16 Feb 2021 12:30:03 +0100

LTIN, Necmi/0000-0003-3294-9782; ALTIN, Necmi/0000-0003-3294-9782; WOS: 000406726000035 In this study, a 15 kW wireless power transfer system with high frequency and large air gap for electrical vehicle battery charge systems is designed and co-simulations with ANSYS-Maxwell and Simplorer software are performed. The air gap between the primary and the secondary windings are determined as 20 cm for the 15 kW wireless power transfer system. Operation of the designed system for different operation conditions such as completely aligned windings (ideal condition) and windings with alignment errors, which can occur because of user error or another reason, are analyzed and obtained results are reported. The resonant frequency of the designed system which has a 60 x 60 cm secondary winding and a 60 x 100 cm primary winding is 17.702 kHz, and the maximum efficiency of the system is obtained as 75.38% for completely aligned windings. The distribution and density of the electromagnetic flux, and variation of efficiency versus load level of the system and responses of the system in case of different alignment errors are also investigated and reported for both ideal operation conditions and in case of alignment errors. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Comparing the modeling of delay propagation in the US and European air traffic networks

Scipedia content — Tue, 16 Feb 2021 12:10:54 +0100

Complex Systems are those in which a very large number of elements interact, usually in a non-linear fashion, producing emergent behaviors that are typically difficult to predict. Air transportation systems fall in this category, with a large number of aircraft following a pre-scheduled program. It has been shown that it is possible to understand and forecast delays propagation in these systems. The objective of this analysis is to compare the modeling in the US and in the European air traffic networks, analyzing the propagation of delays due to failures in the schedule or to disturbances. We use two different agent based models recently developed to simulate the delays propagation and assess the effect of disruptions in the networks (US and ECAC areas). Our results show that a first-come first-served protocol managing the flights produces larger congestion when compared with an ATFM (Air Traffic Flow Management) slots priority system.

This work is co-financed by EUROCONTROL acting on behalf of the SESAR Joint Undertaking (the SJU) and the EUROPEAN UNION as part of TREE project under the Work Package E in the SESAR Programme. Bruno Campanelli is funded by the Conselleria d'Educació, Cultura i Universitats of the Government of the Balearic Islands and the European Social Fund. José J. Ramasco acknowledges funding from the Ramón y Cajal program of the Spanish Ministry of Economy (MINECO).

Peer reviewed

Conceptual Design of a Small Hybrid Unmanned Aircraft System

Scipedia content — Tue, 16 Feb 2021 12:08:43 +0100

UAS (Unmanned Aircraft System) technologies are today extremely required in various fields of interest, from military to civil (search and rescue, environmental surveillance and monitoring, and entertainment). Besides safety and legislative issues, the main obstacle to civilian applications of UAS systems is the short time of flight (endurance), which depends on the equipped power system (battery pack) and the flight mission (low/high speed or altitude). Long flight duration is fundamental, especially with tasks that require hovering capability (e.g., river flow monitoring, earthquakes, devastated areas, city traffic monitoring, and archeological sites inspection). This work presents the conceptual design of a Hybrid Unmanned Aircraft System (HUAS), merging a commercial off-the-shelf quadrotor and a balloon in order to obtain a good compromise between endurance and weight. The mathematical models for weights estimation and balloon static performance analysis are presented, together with experimental results in different testing scenarios and complex environments, which show 50% improvement of the flight duration.

Document type: Article

Light vehicle model for dynamic car simulator

Scipedia content — Tue, 16 Feb 2021 11:56:25 +0100

Driving simulators have been becoming little by little a suitable tool oriented to improve the knowledge about the domain of driving research. The investigations that can be conducted with this type of tool concern the driver’s behaviour, the design/control of vehicles, testing assistance systems for driving and the roadway infrastructure’s impact. The benefits of simulation studies are many: lack of any real risk to users, reproducible situations, time savings and reduced testing costs. In addition, their flexibility allows to test situations that do not exist in reality or at least they rarely and randomly exist. The topic of the present work concerns the development of a brand new dynamic model for an existing car simulator owned by LEPSIS laboratory (Laboratoire d’Expliotation, Perception, Simulateurs et Silulations – Laboratory for Road Operations, Perception, Simulators and Simulations) belonging to COSYS (COmposants et SYStems), which is a department of IFSTTAR institute (Institut Français des Sciences et Technologies des Transports, de l’Aménagement et des Réseaux – French Institute of Science and Technology for Transport, Spatial Planning, Development and Networks) site. Once uses and advantages of driving simulators are listed and described, imperfections and limitations of the existing driving vehicle model belonging to the two Degrees of Freedom (DoF) driving simulator of the laboratory are highlighted. Subsequently, structure of the brand new vehicle model, designed by means of Matlab Simulink software, are illustrated through the theoretical framework. Since the vehicle model must refer to a real one, an instrumented Peugeot 406 has been chosen because all its technical features are provided and inserted both on the present model and Prosper/Callas 4.9 by OKTAL software to create a highly sophisticated and accurate virtual version of the commercial car. The validation of this new vehicle model is performed, where the results returned by several different driving scenarios are compared with the ones provided by Prosper software. All the scenarios are simulated with both existing and new vehicle model uploaded in the driving simulator, and the outputs are subsequently compared with the ones returned by Prosper in order to demonstrate the improvements done. Finally, being the number of outputs provided by the new model definitively higher with respect to previous one, additional validations concerning the further results are accomplished.

Toward Prevention of Pipeline Integrity Threats Using a Smart Fiber-Optic Surveillance System

Scipedia content — Tue, 16 Feb 2021 11:54:47 +0100

9 págs.; INSPEC Accession Number: 16375077

This paper presents the first available report in the literature of a system aimed at the detection and classification of threats in the vicinity of a long gas pipeline. The system is based on phase-sensitive optical time-domain reflectometry technology for signal acquisition and pattern recognition strategies for threat identification. The system operates in two different modes: 1) machine+activity identification, which outputs the activity being carried out by a certain machine; and 2) threat detection, aimed at detecting threats no matter what the real activity being conducted is. Different strategies dealing with position selection and normalization methods are presented and evaluated using a rigorous experimental procedure on realistic field data. Experiments are conducted with $\\text{eight}$ machine+activity pairs, which are further labeled as threat or nonthreat for the second mode of the system. The results obtained are promising given the complexity of the task and open the path to future improvements toward fully functional pipeline threat detection systems operating in real conditions. Copyright © 2016, IEEE

GERG partners, European Research Council, Spanish “Plan Nacional de I+D+i”, Comunidad de Madrid, FP7 ITN ICONE program, European Commission, Spanish Ministry of Economy and Competivity, Spanish Ministry of Science and Innovation

Peer Reviewed

An integration of hybrid choice and random regret-based models

Scipedia content — Tue, 16 Feb 2021 11:53:34 +0100

Increasingly, the number of private car tends to exacerbate environmental problems such as emissions, decreasing exhaustible resources, taking land for road and parking spaces, and so forth. The severity of these damaging effects is even more problematic when it is realized that private cars spend the majority of time parked. Public transit could be a good alternative, though it has several shortcomings in terms of door-to-door accessibility, flexibility, personalization and carrying goods. In this context, carsharing systems have recently attracted considerable attention in many cities. These systems provide people the benefits of private cars without the costs and responsibilities of car-ownership. The shared-cars and their operating systems are owned and maintained by carsharing organizations. In order to use a shared-car, people need to join a carsharing organization with deposit and/or monthly membership costs. After that, they can use a shared-car by checking the availability of shared-cars, booking one of them, getting and returning the car at the same designated point-of-departure and paying the costs, including time-based, distance-based and fuel costs. According to the previous research, carsharing systems induce people to sell their own-vehicles and avoid purchasing a new vehicle. Therefore, knowledge of underlying decision-making processes related to joining carsharing system can help designing more attractive systems, thereby alleviating the environmental problems caused by private cars. Several studies have applied state choice experiments to investigate the intention of joining carsharing systems. Although these studies have produced some interesting findings, they have in common some critical limitations. First, prior studies did not consider any alternative behaviors to joining carsharing programs. One of the alternative behaviors is purchasing a new car. If the purchase and operation costs of a new car are reasonable compared to the membership and operation costs and the burdensome procedures of using a shared-car, people might prefer purchasing a new car to joining carsharing. The other alternative behavior is using the current transportation modes: own-car and/or public transit. People may not be interested in joining a carsharing program if current transportation systems sufficiently satisfy their needs. Second, uncertainties underlying carsharing decisions have been largely ignored in previous studies. Since a car is shared by a number of members, there is some inherent uncertainty in obtaining a car whenever they want. In addition, it is more difficult for people to anticipate the expected travel costs by a shared-car than those of a private car or public transit because the usage cost of a shared-car depends on various types of unit cost, which are greatly different from a private car and public transit, and are more sensitive to activity-travel durations. Therefore, it might be expected that these uncertainties play important roles in decisions to join carsharing. The present study develops an integrated model by incorporating random regret into a hybrid choice modeling framework in order to simultaneously consider satisfactions with the current transportation system and the uncertainties in the carsharing decision. Random regret is employed to account for people’s decision-making behavior under the uncertainties of the carsharing system. The model postulates that people choose an alternative which minimizes anticipated random regret. By integrating these modelling approaches, the proposed model allows us to simultaneously understand the effects of the satisfaction of the current system on the carsharing decision under the uncertainties. The parameters are estimated based on a stated choice data about the intention of joining carsharing against purchasing a new car and using the current systems. Before completing the stated choice experiment, respondents were asked the qualities of their current travel modes and their satisfaction with the systems. Some of these actual qualities were shown in the stated choice experiment as the attributes of the current systems and utilized as reference points to set attributes levels of a new car and a shared-car. The knowledge obtained by our empirical study would be useful to establish more effective strategies to increase the number of users of carsharing programs.

Assessment of Automated Driving Systems using real-life scenarios

Scipedia content — Tue, 16 Feb 2021 11:52:15 +0100

More and more Advanced Driver Assistance Systems (ADAS) are entering the market for improving both safety and comfort by assisting the driver with their driving task. An important aspect in developing future ADAS and Automated Driving Systems (ADS) is testing and validation. Validating the failure rate of an ADS requires so many operational hours that testing in real time is almost impossible. One way to reduce this test load is virtual testing or hardware in-The-loop testing. The major challenge is to create realistic test cases that closely resemble the situation on the road. We present a way to use data of naturalistic driving to generate test cases for Monte-Carlo simulations of ADS. Because real-life data is used, the assessment allows to draw conclusions on how the ADS would perform in real traffic. The method, developed in EU AdaptIVe, is demonstrated by testing an Adaptive Cruise Control (ACC) system in scenarios where the predecessor of the ego vehicle is braking. We show that the probability of the occurrence of unsafe situations with the ACC system can be accurately and efficiently determined.

Design and testing of an innovative monitoring system for railway vehicles

Scipedia content — Tue, 16 Feb 2021 11:48:37 +0100

In recent years there has been increased interest in developing a safer and more efficient railway system, as the railway has demonstrated the potential to become the most sustainable mode of transport. In Europe, significant investments have been made in order to increase the speed of both passenger and freight vehicles, but a good efficiency of railway transport can be achieved only if it is possible to ensure a high level of safety and reliability. These requirements can be achieved by adopting onboard diagnostic systems in order to increase the vehicle safety and to improve the strategies for a scheduled and corrective maintenance. This study shows the design and testing of an onboard monitoring system, which can be installed on different types of railway vehicles. The system is able to detect anomalies of the running behavior of vehicles and faults at the component level.

Evolution toward an open value system for smart mobility services

Scipedia content — Tue, 16 Feb 2021 11:47:08 +0100

The markets around transport and mobility are undergoing significant changes. One of the central drivers for these changes is the deployment of information and communications technology throughout the transport system, which in turn enables a wide range of smart mobility services. At the moment, however, smart mobility services are rather fragmented and work in isolated silos. A key issue in future development is how these isolated systems will become interconnected and in general more open. In this article, we apply the framework introduced by Ali-Vehmas and Casey (2012) to model how the evolution toward an open value system for smart mobility services could occur in Finland. In particular, we apply analogies from the emergence of GSM-based mobile networks and the Internet where the former has followed a more centralized path and the latter a more decentralized path.

A New Methodology for 3D Target Detection in Automotive Radar Applications

Scipedia content — Tue, 16 Feb 2021 11:46:50 +0100

Today there is a growing interest in automotive sensor monitoring systems. One of the main challenges is to make them an effective and valuable aid in dangerous situations, improving transportation safety. The main limitation of visual aid systems is that they do not produce accurate results in critical visibility conditions, such as in presence of rain, fog or smoke. Radar systems can greatly help in overcoming such limitations. In particular, imaging radar is gaining interest in the framework of Driver Assistance Systems (DAS). In this manuscript, a new methodology able to reconstruct the 3D imaged scene and to detect the presence of multiple targets within each line of sight is proposed. The technique is based on the use of Compressive Sensing (CS) theory and produces the estimation of multiple targets for each line of sight, their range distance and their reflectivities. Moreover, a fast approach for 2D focus based on the FFT algorithm is proposed. After the description of the proposed methodology, different simulated case studies are reported in order to evaluate the performances of the proposed approach.

Document type: Article

Valuation of active blind spot detection systems by younger and older adults

Scipedia content — Tue, 16 Feb 2021 11:45:51 +0100

Due to their disproportional representation in fatal crashes, younger and older drivers both stand to benefit from in-vehicle safety technologies, yet little is known about how they value such technologies, or their willingness to adopt them. The current study investigated older (aged 65 and greater; N = 49) and younger (ages 18-23; N = 40) adults’ valuation of a blind spot monitor and asked if self-reported visual difficulties while driving predicted the amount participants were willing to pay for a particular system (BMW's Active Blind Spot Detection System) that was demonstrated using a short video. Large and small anchor values ($250 and $500, respectively) were used as between subjects manipulations to examine the effects of initial valuation, and participants proceeded through a short staircase procedure that offered them either the free installation of the system on their current vehicle or a monetary prize ($25-$950) that changed in value according to which option they had selected in the previous step of the staircase procedure. Willingness to use other advanced driver assistance systems (lane-departure warning, automatic lane centering, emergency braking, adaptive cruise control, and self-parking systems) was also analyzed, additionally controlling for prior familiarity of those systems. Results showed that increased age was associated with a higher valuation for the Active Blind Spot Detection System in both the large and small anchor value conditions controlling for income, gender, and technology self-efficacy. Older adults valued blind spot detection about twice as much ($762) as younger adults ($383) in the large anchor condition, though both groups’ values were in the range for the current cost of an aftermarket system. Similarly, age was the most robust positive predictor of willingness to adopt other driving technologies, along with system familiarity. Difficulties with driving-related visual factors also positively predicting acceptance levels for adaptive cruise control and emergency braking systems. Results are discussed in comparison to older adults’ willingness to pay for other home-based assistive technologies aimed at improving well-being and independence.

Challenges in Slug Modeling and Control for Offshore Oil and Gas Productions:A Review Study

Scipedia content — Tue, 16 Feb 2021 11:44:42 +0100

The upstream offshore multi-phase well-pipeline-riser installations are facing huge challenges related to slugging flow: An unstable flow regime where the flow rates, pressures and temperatures oscillate in the multi-phase pipelines. One typical severe slug is induced by vertical wells or risers causing the pressure to build up and hence originates the oscillating pressure and flow. There exist many negative consequences related to the severe slugging flow and thus lots of investments and effort have been put into reducing or completely eliminating the severe slug. This paper reviews in details the state-of-the-art related to analysis, detection, dynamical modeling and elimination of the slug within the offshore oil & gas Exploration and Production (E&P) processes. Modeling of slugging flow has been used to investigate the slug characteristics and for design of anti-slug control as well, however most models require specific facility and operating data which, unfortunately, often is not available from most offshore installations. Anti-slug control have been investigated for several decades in oil & gas industry, but many of these existing methods suffer the consequent risk of simultaneously reducing the oil & gas production. This paper concludes that slug is a well defined phenomenon, but even though it has been investigated for several decades the current anti-slug control methods still have problems related to robustness. It is predicted that slug-induced challenges will be even more severe as a consequence of the longer vertical risers caused by deep-water E&P in the future.

Climate change in asset management of infrastructure: A riskbased methodology applied to disruption of traffic on road networks due to the flooding of tunnels

Scipedia content — Tue, 16 Feb 2021 11:43:10 +0100

This paper presents a risk-based method to quantify climate change effects on road infrastructure, as a support for decision-making on interventions. This can be implemented in climate adaptation plans as an element of asset management. The method is illustrated by a specific case in which traffic on a road network is disrupted by the flooding of a tunnel due to extreme rainfall. Novel techniques to describe both probability of occurrence and consequences of an event are integrated into the proposed risk-based approach. To model a typical climate-change related phenomenon, i.e. rainfall intensity-duration, a model using copulas is proposed as well as a method to account for uncertainty using structured expert judgement. To quantify the consequences, an existing quick scan tool is adopted. The method calculates the risk of flooding of a tunnel, expressed in both probability of occurrence and subsequent additional travel duration on the road network. By comparison of this evolving risk to a societally acceptable threshold, the remaining resilience of the tunnel is evaluated. Furthermore, the method assesses the development of the resilience over time as a result of projected climate change. The maximum time-to-intervention is defined as the period up until the moment when the resilience is depleted. By application of the method to a tunnel in two different contexts, i.e. in a regional road network and a highway network, it is shown that the consequences of tunnel flooding may differ by an order of magnitude (25-fold for the example). Using a risk-based decision-making perspective leads to significant differences in the maximum time-to-intervention. In the example case the year of intervention is determined at 2020 for a tunnel in a highway network, while interventions can be postponed until 2140 in a regional road network. © 2016, Editorial Board EJTIR. All rights reserved.

Robust Energy Scheduling in Vehicle-to-Grid Networks

Scipedia content — Tue, 16 Feb 2021 11:40:20 +0100

The uncertainties brought by intermittent renewable generation and uncoordinated charging behaviors of EVs pose great challenges to the reliable operation of power systems, which motivates us to explore the integration of robust optimization with energy scheduling in V2G networks. In this article, we first introduce V2G robust energy scheduling problems and review the stateof- the art contributions from the perspectives of renewable energy integration, ancillary service provision, and proactive demand-side participation in the electricity market. Second, for each category of V2G applications, the corresponding problem formulations, robust solution concepts, and design approaches are described in detail based on the characteristics of problem structures and uncertainty sets. Then, an adjustable robust energy scheduling solution is proposed to address the over-conservatism problem by exploring chance-constrained methods. Results demonstrate that the proposed algorithm not only can efficiently shift the peak load and reduce the total operation cost, but also provide great flexibility in adjusting the trade-off between economic performance and reliable operation. Finally, we present key research challenges and opportunities.

The spatial scope of airline competition

Scipedia content — Tue, 16 Feb 2021 11:35:42 +0100

We investigate whether alternative city- or airport pairs are viable substitutes and the extent to which they impact airline competition between the United Kingdom and continental Europe. To this end, we employ and measure airlines’ best responses in equilibrium. Using monthly airline-route seat capacity levels and two stage least-squares dummy-variables regression models, we estimate airlines’ strategic reaction to the competitors’ capacity levels, including competitors on other routes. We show that airlines’ relevant market extends beyond the airport-pair level. Strategic reactions depend on airline type, but all airline types have a similar strategic reaction towards high speed rail.

Value assessment of aggregated energy flexibility when traded on multiple markets

Scipedia content — Tue, 16 Feb 2021 11:34:58 +0100

ggregated demand response for smart grid services is a growing field of interest especially for market participation. A growing trend in research is to utilize aggregated demand response for multiple smart grid services. This could be multi-market trading (day ahead, intraday and imbalance) or a combination of market and ancillary services such offering reserve power or congestion management. However, there is a potential conflict of interest when offering the same resource for simultaneous services. This work investigates the impact, both from a monetary and network stability perspective, of applying a predictive control trading strategy which actively offers aggregated flexibility of electric vehicles on both the German EPEX day ahead and intraday markets. An artificial neural network was used to forecast the available ramp up and down capacity of a Virtual Power Plant (VPP) of 1000 electric vehicles. Using this information, the available flexibility is traded to ramp up in one quarter and down in the next depending on the price delta seen in the intraday market. A number of simulation runs are done, each with different levels of flexibility traded. In every run, one week of realistic VPP behaviour is simulated. The total earnings on the intraday market are calculated as well as imbalance cost and imbalance power generated over this period. It was seen that with an increased offer of available flexibility, there was an increase in both total revenues up to ∼4200 euros for one week of trade as well as imbalance generated, ∼1.6 MWh. Therefore, there is a clear need for effective regulation that limits imbalance without losing the future grid-stabilising effects of the flexibility aggregator.

A comparison between Carsonâs formulae and a 2D FEM approach for the evaluation of AC interference caused by overhead power lines on buried metallic pipelines

Scipedia content — Tue, 16 Feb 2021 11:23:51 +0100

In this paper, the AC interference produced by an overhead power transmission line on a buried metallic pipeline is estimated using a circuital method based on the well-known Carsonâs formulae and a two-dimensional finite element numerical code. The finite element formulation used in this paper implicitly takes into account the mutual inductive coupling between all the considered conductors, and it allows a more detailed analysis in cases where a nonhomogeneous soil is present. The FEM approach includes a procedure which has been developed to enforce that the sum of the currents flowing through the soil, pipeline and eventual overhead ground wire is equal to zero. A case study has been identified, and the results obtained by the two approaches have been compared and discussed.

Implications of the New EU Maritime Emission Monitoring Regulation on Ship Transportation of CO2

Scipedia content — Tue, 16 Feb 2021 11:23:29 +0100

In the framework of the CCSP R&D program, the regulatory gaps have been assessed at VTT using the current monitoring rules for capture, pipeline transportation and geological storage of CO"sub"2"/sub" as a benchmark. The scope of the presented work includes: (i) definition of CO"sub"2"/sub" emissions from ship transportation of CO"sub"2"/sub"; (ii) review of EU regulations on MRV of maritime CO"sub"2"/sub" emissions; and (iii) review of the MRV regulation on capture, transport and geological storage of CO"sub"2"/sub" under the EU-ETS. The considered activities related to ship transportation of CO"sub"2"/sub" are liquefaction and intermediate storage with recirculation loop for boil-off CO"sub"2"/sub", loading and unloading facilities and CO"sub"2"/sub" transportation and handling during the ship voyage. Identification of the regulatory gaps, based on the above, shows what is needed to enable ship transportation of CO"sub"2"/sub" for geological storage in Europe. Based on the results, maritime transportation for CCS could be made possible with very limited new emission monitoring and verification practices. Also the trade-offs of using an MRV regulation analogous to pipeline transportation of CO"sub"2"/sub" is discussed in the results.

Measuring connectivity in the air freight industry

Scipedia content — Tue, 16 Feb 2021 11:19:52 +0100

In this paper, we present an air transport connectivity model for air freight. For the purposes of this paper, connectivity is defined as all possible direct and indirect connections to or from an airport operated by wide-body aircraft, weighted for the quality of the connection in terms of transhipment and in-flight times. Using this model, we analyse the networks of seven European airports. Europeâ€™s largest hub airports carry most air freight thanks to their extensive intercontinental passenger networks, while smaller airports with a strong focus on air freight carry large amounts of cargo on dedicated freighter aircraft. For air freight operations, the catchment area of an airport is much larger than it is for passenger services, as shipments are being trucked to their departure airport throughout all of mainland Europe. Since there are many airports sharing the same catchment area, potential competition for air freight is fierce. We found that well located regions between the four large European airports have access to large air freight networks, whilst regional air freight connectivity in northern and southern parts of Europe is substantially lower.

Quantifying the impact of adverse weather conditions on road network performance

Scipedia content — Tue, 16 Feb 2021 11:14:40 +0100

dverse weather conditions regularly lead to severe congestion and large travel time delays on road networks all over the world. Different climate scenarios indicate that in the future adverse weather conditions are likely to become more frequent, last longer and will be more extreme. Although climate mitigation measures are being taken, it remains important to investigate how adverse weather events will affect the performance of the road network in the future. The main objective of this paper is to give an overview of how the impact of adverse weather conditions and adaptation measures on road network performance can be quantified. A literature review has been performed to show what is empirically known about the impact of adverse weather conditions on the road network performance. Furthermore, available methods to quantify the impact of adverse weather conditions and adaptation measures on the road network performance for future situations are reviewed. As an example, a case study for the municipality of Rotterdam has been carried out that shows how a combination of models can be used to analyse which links in the road network are most vulnerable for increasingly severe local weather related disturbances. The results of the case study allow local authorities to decide whether or not they need to take adaptation measures. © 2016, Editorial Board EJTIR. All rights reserved.

Integration of vulnerable road users in cooperative ITS systems

Scipedia content — Tue, 16 Feb 2021 11:13:43 +0100

Charging cost optimization for EV buses using neural network based energy predictor

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

For conventional buses, based on the decades of their operational knowledge, public transport companies are able to optimize their cost of operation. However, with recent trend in the usage of electric buses, cost optimal operation can become challenging. In this paper an offline optimal charging strategy is developed to minimize the energy cost. This is done by exploiting the periodicity and predictable operation of the city buses. For effective usage of the developed offline strategy, the actual energy demand of the electric bus must be known a-priori, which can be demanding. In order to address this issue, a predictor is designed. The neural network based predictor is able to estimate the energy demand for the next day. Using this, three different optimal charging strategies are implemented. Initially, only the operational constraints are considered to ensure the completion of a trip, later, a more involved problems consisting of battery state of charge (SoC) constraints and temperature constraints are included for the second and third optimization problems, respectively. All the three approaches result in significant energy cost minimization when compared to the non-optimal strategy of charging the electric bus to the full capacity at every available opportunity. Additionally, for the second and third formulations, namely, SoC and temperature constraints, by using a qualitative aging approach, some enhancements in the battery health is observed when compared to the non-optimal charging strategy.

"Us up here and them down there": how design, management and neighborhood facilities shape social distance in a mixed-tenure housing development

Scipedia content — Tue, 16 Feb 2021 11:09:10 +0100

Despite the fact that social mix is an essential component of urban policies in Western Europe, it remains unclear at what spatial scale housing diversification programs may be most effective. When people with different backgrounds, household compositions, and lifestyles live in close proximity to one another, the emergence of close social ties is not always guaranteed. On the one hand, living in socially mixed environments may create bridges between residents of different social positions. On the other hand, it can lead to processes of social distancing and reproduce negative stereotypes. This article aims to provide insights into how these diverging experiences of social closeness or distance relate to place-specific features such as housing design, management practices, and the structure of local facilities. Lessons are drawn from a qualitative study on resident experiences of living with difference in a fine-grained mixed-tenure development in a newly built neighborhood in Amsterdam, the Netherlands.

Document type: Article

Transport of Human Organs in Italy: Location, Time, and Performances

Scipedia content — Tue, 16 Feb 2021 11:08:13 +0100

Introduction The outcome of transplantation activities depends on a variety of unpredictable factors. Up-to-date criteria on organ allocation foresee an efficient transport chain along with compliant performance parameters. Methods and Objectives The Centro Nazionale Trapianti and the Department of Civil, Chemical, Environmental, and Materials Engineering of the University of Bologna (respectively, CNT and DICAM) have been updating a national database of organ transplantation activities to investigate performance parameters and the main causes of disruption. Results Between June 2015 and July 2016, 617 of 1061 organs have been shipped by air (making for 486 flight events), of which 407 were accompanied by medical equipment. Origin/destination and distance matrixes have been drawn for both road and air transport. Each airport node is ranked based on the n° of organs ingoing/outgoing and each route link on its frequency. Performance parameters such as average speed, distance covered, and time have been computed and compared with each organ's cold ischemia time (CIT). Average distance frontiers are rather homogeneous, but much effort is necessary to reduce the number of events performed with approximately 90% or more of CIT spent. Conclusions The monitoring of organ transplantation activities' performance is a standalone action within Europe to support strategic policies to optimize the system. Thus, a clearer awareness on performances and issues related to organ transport has been made possible: analyses show that the higher uncertainty associated with total time of displacement by air is due to the steps which take place by road (length and paths must be optimized) and lung transports generally perform weaker than heart transports due to longer average distances travelled and smaller average speeds, often resulting in a total displacement time greater than 90% of CIT.

Improving the gossiping effectiveness with distributed strategic learning (Invited paper)

Scipedia content — Tue, 16 Feb 2021 11:06:26 +0100

Gossiping is a widely known and successful approach to reliable communications, tolerating packet losses and link crashes. It has been extensively used in several middleware kinds, such as event notification services and application domains, like infrastructures for air traffic management, power grid control, health information exchange, just to cite some of them. Despite achieving a high loss-tolerance and scalability degrees, gossiping is affected by degraded performances and heavy traffic loads on the network. For this reason, it may be not optimal in applications where reliability must be provided jointly with timeliness and/or in congestion-prone networks. The crucial aspect for improving a gossiping scheme is deciding which nodes should receive a gossiping message, and our driving idea is to adopt a distributed strategic learning logic to determine such nodes in an efficient manner. This is able to resolve gossiping's weakness points and to achieve better performance and reduced traffic loads. This paper describes how to introduced strategic learning in a gossip scheme so as to determine the best set of nodes that can be used to send gossip messages and to optimize their utility. Such a solution has been experimentally assessed through a set of simulations demonstrating the effectiveness of the proposal.

Quantifying the effectiveness of ITS in improving safety of VRUs

Scipedia content — Tue, 16 Feb 2021 11:06:08 +0100

Implications of diesel emissions control failures to emission factors and road transport NOx evolution

Scipedia content — Tue, 16 Feb 2021 11:05:24 +0100

Diesel NOx emissions have been at the forefront of research and regulation scrutiny as a result of failures of late vehicle technologies to deliver on-road emissions reductions. The current study aims at identifying the actual emissions levels of late light duty vehicle technologies, including Euro 5 and Euro 6 ones. Mean NOx emission factor levels used in the most popular EU vehicle emission models (COPERT, HBEFA and VERSIT+) are compared with latest emission information collected in the laboratory over real-world driving cycles and on the road using portable emissions measurement systems (PEMS). The comparison shows that Euro 5 passenger car (PC) emission factors well reflect on road levels and that recently revealed emissions control failures do not call for any significant corrections. However Euro 5 light commercial vehicles (LCVs) and Euro 6 PCs in the 2014–2016 period exhibit on road emission levels twice as high as used in current models. Moreover, measured levels vary a lot for Euro 6 vehicles. Scenarios for future evolution of Euro 6 emission factors, reflecting different degree of effectiveness of emissions control regulations, show that total NOx emissions from diesel Euro 6 PC and LCV may correspond from 49% up to 83% of total road transport emissions in 2050. Unless upcoming and long term regulations make sure that light duty diesel NOx emissions are effectively addressed, this will have significant implications in meeting future air quality and national emissions ceilings targets. © 2016 Elsevier Ltd

First-order traffic flow models incorporating capacity drop: overview and real-data validation

Scipedia content — Tue, 16 Feb 2021 11:01:25 +0100

The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 321132, project TRAMAN21. Summarization: First-order traffic flow models of the LWR (Lighthill-Whitham-Richards) type are known for their simplicity and computational efficiency and have, for this reason, been widely used for various traffic engineering tasks. However, these first-order models are not able to reproduce significant traffic phenomena of great interest, such as the capacity drop and stop-and-go waves. This paper presents an overview of modeling approaches, which introduce the ability to reflect the capacity-drop phenomenon into discretized LWR-type first order traffic flow models; and also proposes a new approach. The background and main characteristics of each approach are analyzed with particular emphasis on the practical applicability of such models for traffic simulation, management and control. The presented modeling approaches are tested and validated using real data from a motorway network in the U.K. Presented on: Transportation Research Part B: Methodological

Transport reduction by crowdsourced deliveries – a library case in Finland

Scipedia content — Tue, 16 Feb 2021 10:58:06 +0100

The paper presents a case study of applying crowdsourcing to library deliveries. The trial was conducted in the city of Jyvaskyla in Finland as part of the Resource Wise Communities program funded by The Finnish Innovation Fund Sitra. The city has a population of 120 000 inhabitants and is facing the shut-down of half of the public libraries in order to adapt its economy to lowered revenues and compulsory cost savings. The assumption was that the level of service for customers not able to settle for e-books would be lowered and/or customers would have to travel longer distances. However, a research pilot was carried out where –instead of lowering the level of service in the area– books and other library media were delivered to customers' homes by utilizing a novel crowdsourced delivery service called PiggyBaggy. Crowdsourced delivery means that citizens deliver goods to each other along their way. Ideally, the deliveries would be made with minimal detour, along the way, thus maximizing the reduction in natural resource use and related environmental impacts from the transport. However, the transport fuel forms only one part of the overall footprint and in practice rebound effects such as drivers traveling longer distances motivated by monetary compensation, can reduce the targeted environmental improvement. The objective of our study was to investigate whether an existing consumer service, in this case the library public service, can adopt crowdsourced deliveries quickly from scratch, and to whether consumers participate in the deliveries in a way that has real sustainability benefits. Despite prevailing regulative challenges, the study found that existing library deliveries can be successfully crowdsourced. Each crowdsourced delivery reduced an average of 1.6 km driven by car, despite 80 per cent of the deliveries being made within less than a 5-km distance. Mobility related footprint reduction potential for Finland is also estimated.

Event-based, 6-DOF Camera Tracking from Photometric Depth Maps

Scipedia content — Tue, 16 Feb 2021 10:54:34 +0100

Event cameras are bio-inspired vision sensors that output pixel-level brightness changes instead of standard intensity frames. These cameras do not suffer from motion blur and have a very high dynamic range, which enables them to provide reliable visual information during high-speed motions or in scenes characterized by high dynamic range. These features, along with a very low power consumption, make event cameras an ideal complement to standard cameras for VR/AR and video game applications. With these applications in mind, this paper tackles the problem of accurate, low-latency tracking of an event camera from an existing photometric depth map (i.e., intensity plus depth information) built via classic dense reconstruction pipelines. Our approach tracks the 6-DOF pose of the event camera upon the arrival of each event, thus virtually eliminating latency. We successfully evaluate the method in both indoor and outdoor scenes and show that---because of the technological advantages of the event camera---our pipeline works in scenes characterized by high-speed motion, which are still unaccessible to standard cameras.

Comment: 12 pages, 13 figures. 2 tables. (in press)

Visual aids for safe operation of remotely piloted vehicles in the controlled air space

Scipedia content — Tue, 16 Feb 2021 10:52:30 +0100

The paper presents a set of visual AIDS for enhancing remote pilot perception of potential violations of allowed fly areas or conflicts with conventional air traffic when operating remotely piloted aerial vehicles. Assuming a video stream from an on-board camera is available to the remote pilot, visual AIDS are provided in a head-up display modality by means of reality augmentation techniques. The main visual element consists of a dynamic set of fences allowing for a safe aircraft separation away from no-fly zones and from neighboring vehicles. The shape of the fences is varied according to aircraft current speed and altitude, in order to allow for a sufficient safety margin, also in case of a loss-of-control accident. As a further visual aid, the predicted future position of the aircraft is determined and fence color is changed in order to highlight potential violations of the allowed operational area. The proposed methodology is validated by means of simulations in a reference operational scenario. Results demonstrate the effectiveness of the proposed approach in improving pilot awareness.

Modeling the fuel flow-rate of transport aircraft during flight phases using genetic algorithm-optimized neural networks

Scipedia content — Tue, 16 Feb 2021 10:49:24 +0100

WOS: 000369198300006

Predicting the fuel consumption of transport aircraft is vital for minimizing the detrimental effects of fuel emissions on the environment, saving fuel energy sources, reducing flight costs, achieving more accurate aircraft trajectory prediction, and providing effective and seamless management of air traffic. In this study, a genetic algorithm-optimized neural network topology is designed to predict the fuel flow-rate of a transport aircraft using real flight data. This model incorporates the cruise flight phase and the fuel consumption dependency with respect to both the variation of true airspeed and altitude. Feed-forward backpropagation and Levenberg-Marquardt algorithms are applied, and a genetic algorithm is utilized to design the optimum network architecture regarding time and effort. The predicted fuel flow-rates closely match the real data for both neural network training algorithms. Backpropagation gives the best accuracy for the climb and cruise phases, whereas the Levenberg-Marquardt algorithm is optimal for the descent phase

Joint Fact-Finding in Practice: Review of a Collaborative Approach to Climate-Ready Infrastructure in Rotterdam

Scipedia content — Tue, 16 Feb 2021 10:48:02 +0100

Joint fact-finding has been advanced as a method for helping stakeholders grappling with technically intensive policy and planning challenges to collaboratively engage in research and arrive at shared sets of facts to inform their decision-making. This paper introduces joint fact-finding and considers its application in the context of infrastructure stakeholders aiming to assess and increase the resilience of their infrastructure systems to climate change. A set of evaluative criteria is introduced, which are proposed for assessing joint fact finding processes both procedurally and substantively in terms of the outcomes, considering them to be both arenas for collaborative governance and joint knowledge production efforts. These criteria are applied to a case in Rotterdam, the Netherlands. This case suggests that joint fact-finding can provide value, but also reveals some lessons. For the efforts themselves, these lessons relate to: The practical applicability of the outcomes; the inherently contingent nature of the outcomes when addressing wicked problems; questions of representation from stakeholder groups; and the importance of leadership and good process design. The following observations are made regarding the criteria: While they are typically interdependent, both process and outcomes should be evaluated; and more attention should be paid to the method and metrics of evaluation, while recognizing that there is no single formula or approach that can be applied, given the heterogeneity of the criteria. © 2016, Editorial Board EJTIR. All rights reserved.

North European Export Industry and the Shadows of Sulphur Directive

Scipedia content — Tue, 16 Feb 2021 10:37:59 +0100

"jats:p"EU Directive of MARPOL Annex VI and its economic impact on the Nordic paper industry is theme of this research work. Empirical data for analysis purposes was gained from a large Nordic paper mill that exports bulk products mainly to Europe (70 % of its volume). The study shows that in the end the industry’s location still has an economical effect, and that the location has a distinct impact on competition through rising transportation costs. Environmental regulation continues and fosters long-term upwards trajectory of transportation cost, which has been experienced by the paper mill earlier during years 2001-2009. Sulphur regulation change to cleaner grades of maritime diesel did not turn as heavy cost increase in the 2015, however, possibility to gain cost benefits in rapidly deteriorating oil markets were not reached either. Therefore, in depressed industrial product markets, like paper industry, implications were such that margins of export industry remained low.

Document type: Article