Scipedia: Documents published in 2015

Stress-strain state of pipeline depending on complicated environment

Scipedia content — Mon, 01 Feb 2021 19:50:10 +0100

The paper presents the 3D model and FEM analysis of the stress-strain state of the soil- pipe interaction system. The analysis shows that the geological environment has shown a strong effect on the pipelines. This stress-strain analysis is carried out using the ANSYS finite element program.

Quantifying the benefits of peak spreading as a sustainable solution to addressing traffic congestion within the Al Ain private school zone in Abu Dhabi, United Arab Emirates

Scipedia content — Mon, 01 Feb 2021 19:44:54 +0100

Owing to the over-concentration of about 40 schools along an approximately 5km stretch of an urban street within the City of Al Ain, United Arab Emirates (UAE), daily traffic experiences and motorists frustrations manifested in terms of intersection delay, travel time, queues, travel speed and emissions have reached intolerable levels. While varied efforts are being put in place to address the situation, the Department of Transport (DoT) embarked on a pilot study that involved staggering of the starting time of schools over a time interval of 30 minutes for two weeks. The main objective of the study was to examine the effect of peak spreading on minimizing roadway congestion and other externalities within the private school zone. The study was cross-sectional in nature and involved traffic data collection before the implementation of the staggered school starting times and during the scheme. This purpose of paper therefore summarizes the findings of the scheme in quantifiable attributes of intersection delays, link travel times and traffic volumes intensities; and also formed the basis for recommendations to further address traffic congestion within the private school zone.

Development of traffic light control algorithm in smart municipal network

Scipedia content — Mon, 01 Feb 2021 19:43:08 +0100

This paper presents smart system that bypasses the normal functioning algorithm of traffic lights, triggers a green light when the lights are red or reset the timer of the traffic lights when they are about to turn red. Different pieces of hardware like microcontroller units, transceivers, resistors, diodes, LEDs, a digital compass and accelerometer will be coupled together and programed to create unified complex intelligent system.

Does public transit reduce car travel externalities? Quasi-natural experiments' evidence from transit strikes

Scipedia content — Mon, 01 Feb 2021 19:24:25 +0100

The provision of public transit is thought to reduce travel time losses that are due to car congestion. For this reason, it is economically justified to subsidise public transit from a welfare perspective as it creates a congestion-relief benefit. The main goal of this paper is to quantify the congestion-relief benefit of public transit for Rotterdam by analysing car speed during public transit strikes. Arguably, strikes can be interpreted as exogenous transit supply shocks and therefore as a quasi-natural experiment. We are aware of two other papers that use the same methodology. Lo and Hall (2006) and, more recently, Anderson (2014) both analyse the effect of (the same) single transit strike lasting 35 days on highway speed for Los Angeles. Anderson (2014) finds a substantial congestion relief benefit with a decrease in time delays experienced by car drivers of 0.12 minutes per kilometer traveled. It is unknown to what extent this result can be generalised to cities where the share of public transit use is much higher or to cities where bicycle use might be a viable alternative. Our analysis differs from Anderson (2014) and Lo and Hall (2006) in a number of ways. First, we focus on a city, Rotterdam in the Netherlands, which, as we will document, is only mildly congested. Second, we analyse the effect of multiple strikes of various public transit modes (e.g. bus, light rail) that are citywide. Third, we examine the strike effect on car speed (and flow) both for the highway ring road as well as within the inner-city of Rotterdam. Finally, by examining heterogeneity in the effects of strikes, we are able to improve our understanding when the public transit relief benefit is particularly pronounced. For example, as one may expect, we find a particularly strong effect of strikes on car speed during weekday rush hours (but no clear effect during weekends and outside rush hours). In addition, our results suggest that the speed effects of strikes that last a few hours are similar to full-day strikes indicating that a continuous supply of public transit during the day is essential for travelers. We show that the congestion relief impact in Rotterdam is by a factor ten larger for inner city roads than for highway ring roads. For the latter we found a several times smaller effect than Anderson (2014). It turns out that the congestion relief benefit of public transit for Rotterdam is substantial, and about 50% of the current subsidy level. This result is particularly noteworthy as we focus on what can be considered an uncongested city. This suggests that subsidies to public transit are welfare improving, even for cities that exhibit low congestion levels.

ATHENIS_3D: Automotive Tested High-voltage and Embedded Non-volatile Integrated SoC Platform with 3D Technology

Scipedia content — Mon, 01 Feb 2021 19:20:45 +0100

The ATHENIS-3D FP7 EU project aims at providing new enabling technologies (analog, digital and power components) for high-voltage and high-temperature applications, tested for power systems of new hybrid/electrical vehicles. Innovation is exploited at process/device level (3D chip stacking, wafer level packaging, trench capacitors and TSV-inductors integrated in the interposer, high-reliable non-volatile Magnetic RAM), circuit-level (inductorless high-voltage DC-DC converter, high-temperature 28nm System-on-Chip platform) and system-level (compact 3D embedded power mechatronic system). Enabling high integration levels of complex systems, operating in harsh environments, in a single packaged 3D device, ATHENIS-3D allows for one order of magnitude area reduction vs. today PCB-based power and control systems. Integration costs will be consequently reduced in key industrial sectors for Europe where high-voltage/temperature operations are mandatory (vehicles, avionics, space/defense, industrial automation, energy). © 2016 EDAA.

Anticipatory Shifting - Optimization of a Transmission Control Unit for an Automatic Transmission through Advanced Driver Assistance Systems

Scipedia content — Mon, 01 Feb 2021 16:29:56 +0100

By integrating system simulation with vehicle dynamics into real-time environments, it is possible to simulate the physically correct behavior of vehicle components and also adjust it to the required operating strategies depending on external factors. Multi-physics system simulation for realistic representations of powertrains and their behavior combined with dynamic driving simulation allows for optimizations of the transmission control unit for an automatic transmission by employing advanced driver assistance systems for an increased efficiency through anticipatory shifting. Realistic load cases that are based on measured data help optimize fuel consumption and driveline dynamics with respect to the control algorithms by using variation calculations with variable transmission parameters. This works also the other way around when control algorithms are validated and optimized quickly and free of risk as part of rapid prototyping.

Content-based Publish / Subscribe communication paradigm offers a new approach to disseminate messages in the network, where the message content determines the recipients. Many applications used on AANETs, which are a subclass of VANETs, could be more efficient using this paradigm. Many Publish / Subscribe systems suitable for VANETs have been developed, however they are not efficient for some AANET applications. A promising approach is to build a Publish / Subscribe system over a cluster structure to reduce the control overhead and to offer a good scalability. However, the efficiency of this approach strongly depends on the performance of the clustering algorithm. The aim of this article is to propose a new clustering method, named CAPS, which will be the basis for a future content-based Publish / Subscribe system for AANETs. To validate our approach, a simulation model has been developed. Our algorithm has been compared to some other solutions in a modeled AANET context based on real air traffic traces. We show that CAPS gives better results than other solutions in terms of stability while maintaining at a low level the number of cluster groups.

Scipedia content — Mon, 01 Feb 2021 16:28:37 +0100

International audience; Content-based Publish / Subscribe communication paradigm offers a new approach to disseminate messages in the network, where the message content determines the recipients. Many applications used on AANETs, which are a subclass of VANETs, could be more efficient using this paradigm. Many Publish / Subscribe systems suitable for VANETs have been developed, however they are not efficient for some AANET applications. A promising approach is to build a Publish / Subscribe system over a cluster structure to reduce the control overhead and to offer a good scalability. However, the efficiency of this approach strongly depends on the performance of the clustering algorithm. The aim of this article is to propose a new clustering method, named CAPS, which will be the basis for a future content-based Publish / Subscribe system for AANETs. To validate our approach, a simulation model has been developed. Our algorithm has been compared to some other solutions in a modeled AANET context based on real air traffic traces. We show that CAPS gives better results than other solutions in terms of stability while maintaining at a low level the number of cluster groups.

Adaptive Simulated Annealing with Homogenization for Aircraft Trajectory Optimization

Scipedia content — Mon, 01 Feb 2021 16:28:21 +0100

International audience; In air traffic management, most optimization procedures are commonly based on deterministic modeling and do not take into account the uncertainties on environmental conditions (e.g., wind) and on air traffic control operations. However, aircraft performances in a real-world context are highly sensitive to these uncertainties. The aim of this work is twofold. First, we provide some numerical evidence of the sensitivity of fuel consumption and flight duration with respect to random fluctuations of the wind and the air traffic control operations. Second, we develop a global stochastic optimization procedure for general aircraft performance criteria. Since we consider general (black-box) cost functions, we develop a derivative-free optimization procedure: noisy simulated annealing (NSA).

Automated ATM System Enabling 4DT-Based Operations

Scipedia content — Mon, 01 Feb 2021 16:22:17 +0100

part of the current initiatives aimed at enhancing safety, efficiency and environmental sustainability of aviation, a significant improvement in the efficiency of aircraft operations is currently pursued. Innovative Communication, Navigation, Surveillance and Air Traffic Management (CNS/ATM) technologies and operational concepts are being developed to achieve the ambitious goals for efficiency and environmental sustainability set by national and international aviation organizations. These technological and operational innovations will be ultimately enabled by the introduction of novel CNS/ATM and Avionics (CNS+A) systems, featuring higher levels of automation. A core feature of such systems consists in the real-time multi-objective optimization of flight trajectories, incorporating all the operational, economic and environmental aspects of the aircraft mission. This article describes the conceptual design of an innovative ground-based Air Traffic Management (ATM) system featuring automated 4-Dimensional Trajectory (4DT) functionalities. The 4DT planning capability is based on the multi-objective optimization of 4DT intents. After summarizing the concept of operations, the top-level system architecture and the key 4DT optimization modules, we discuss the segmentation algorithm to obtain flyable and concisely described 4DT. Simulation case studies in representative scenarios show that the adopted algorithms generate solutions consistently within the timeframe of online tactical rerouting tasks, meeting the set design requirements.

Magnetic flux leakage and principal component analysis for metal loss approximation in a pipeline

Scipedia content — Mon, 01 Feb 2021 16:14:55 +0100

Safety and reliability of hydrocarbon transportation pipelines represent a critical aspect for the Oil an Gas industry. Pipeline failures caused by corrosion, external agents, among others, can develop leaks or even rupture, which can negatively impact on population, natural environment, infrastructure and economy. It is imperative to have accurate inspection tools traveling through the pipeline to diagnose the integrity. In this way, over the last few years, different techniques under the concept of structural health monitoring (SHM) have continuously been in development.This work is based on a hybrid methodology that combines the Magnetic Flux Leakage (MFL) and Principal Components Analysis (PCA) approaches. The MFL technique induces a magnetic field in the pipeline's walls. The data are recorded by sensors measuring leakage magnetic field in segments with loss of metal, such as cracking, corrosion, among others. The data provide information of a pipeline with 15 years of operation approximately, which transports gas, has a diameter of 20 inches and a total length of 110 km (with several changes in the topography). On the other hand, PCA is a well-known technique that compresses the information and extracts the most relevant information facilitating the detection of damage in several structures. At this point, the goal of this work is to detect and localize critical loss of metal of a pipeline that are currently working.

Document type: Article

Dispersion scenarios for pollution release in an occupied underground station – a numerical study with a micro-scale and a multi-agent model

Scipedia content — Mon, 01 Feb 2021 16:14:22 +0100

The release of hazardous material in a subway station is a dangerous situation for passengers and staff. To achieve an acceptable level of risk, a correct marking of emergency exits and escape routes is essential., For this purpose, underground air dispersion, which depends on source characteristics, the construction layout of the station, and meteorological conditions, must be known. In this paper a micro-scale wind model is combined with a dispersion model to calculate the spread of pollutants underground as well as aboveground for specific scenarios. In particular, the effect of emission temperature on the contamination of the subway facilities was studied. Completely different spots with high concentrations have been calculated for hot and cold sources. Depending on the scenario, an escape route is not always safe, underlining the need for a situation-related adaptive marking system. Further information on the optimisation of a safe way out is provided by the results of an agent-based simulation model. Depending on the number and on the individual characteristics of the agents, the contamination level can be estimated, which could help in the prioritisation process between alternative escape routes.

Enhanced Flatbed Tow Truck Model for Stable and Safe Platooning in the Presences of Lags, Communication and Sensing Delays

Scipedia content — Mon, 01 Feb 2021 16:06:22 +0100

International audience; Many ideas have been proposed to reduce traffic congestion. Driving a platoon of vehicles with constant spacing seems to be a promising idea as it increases traffic density. But keeping constant inter-vehicle spacing requires very reliable communication. Another control policy is to drive the platoon with a time headway between vehicles. It is a robust and well known policy but large inter-vehicle distances in addition to weak stability (unity error gain) near low frequencies make it less practical. We have proposed in [1], [2] a modification of the Constant Time Headway policy (CTH). This modification largely reduces the inter-vehicle distances using only one information shared between all vehicles. In this work, we propose an additional modification of our control law. This modification makes our control law similar, in form, to the classical constant spacing policy, but it requires to share only one information between the vehicles. This modification improves the stability of the platoon and removes the weak stability of the CTH near low frequencies. We prove the robustness of the control law in the presence of actuating lags, sensing and communication delays. This proof can also be used to prove the stability of the classical constant spacing policy in the presence of all previous delays, which makes our result more general than those established in the literature. Safety is also discussed and the maximum acceptable communication delay without losing safety is determined. Simulations have been done in many critical scenarios.

Data Preparation to Simulate Public Transport in Micro-Simulations Using OSM and GTFS

Scipedia content — Fri, 29 Jan 2021 01:02:58 +0100

Research on demand-responsive collective transportation facilities that can act as feeder services to time-table based public transportation (PT) requires detailed and accurate information about the PT infrastructure, including the attachment of bus stops to the appropriate network link. Due to the size of the infrastructure, the data integration shall be automated. This paper describes the effort to prepare data from publicly available OpenStreetMap (OSM) and General Transit Feed Specification (GTFS) sources. Procedures are proposed (i) to build a network derived from OSM suitable for simulations in transportation, (ii) to extract bus stops from GTFS and remove anomalies and (iii) to find candidate network links to attach them. The research reported was partially funded by the IWT 135026 Smart-PT: Smart Adaptive Public Transport (ERANET Transport III Flagship Call 2013 “Future Traveling”).

Reducing Latency in African NRENS Using Performance-Based LISP/SDN Traffic Engineering

Scipedia content — Fri, 29 Jan 2021 00:58:12 +0100

ve topology measurements on the African Internet have showed that over 75% of the intra-Africa traffic destined for Africa’s National Research and Education Networks (NRENs) uses intercontinental links, resulting in high latencies and data transmission costs. The goal of this work is to investigate how latency-based path selection using Locator/Identifier Separation Protocol (LISP) and Software Defined Networking (SDN) in NRENs can be used to reduce inter-NREN latencies. We present aspects of an experimental prototype implementation for real-time topology probes to discover lower-latency remote gateways and dynamic configuration of end-to-end Internet paths. Simulation results indicate that ranking remote ingress gateways, and dynamic configuration of end-to-end paths between gateways can lower the average latency for inter-NREN traffic exchange.

Simulation Model of The Collision Event of Submarine Mudflows Exerting A Horizontal Pipeline

Scipedia content — Fri, 29 Jan 2021 00:57:42 +0100

The collision between submarine slide and sub-sea pipelines was simulated through laboratory experiment in order to investigate drag force exerted by mudflow on pipe surface. Mud model used was slurry of kaolin clay-water mixtures. Gravity flow concepts of fluid mechanics principles were implemented by lock-exchange system. It was developed through the laboratory equipment of rectangular channel to generate the mudflow in water ambient. A crosswise pipe stem positioned at certain run-out distance. It was collided by mudflow. The collision attributes of velocity (u), Reynolds number (Re), maximum drag force exerted by mudflow (Fdmax) and drag force coefficient (Cd) were observed based on ratio between water depth (at pipe position) and pipe diameter, abbreviated as H/d. Overall, higher H/d ratio generated higher values of collision attributes. H/d ratio variations had similar constant of Power-law model expression in Re-Cd relationship. It proved that H/d ratio had not effect to Cd very much. The current experiment also generated a high similarity trend line of Re-Cd relationship graph with the previous study. It indicated that the content of clay material (i.e. kaolin) play a major role in mudflow movement and collision, whereas granular materials (used in previous study) provide an extra density.

Joint prediction of road-traffic and parking occupancy over a city with representation learning

Scipedia content — Fri, 29 Jan 2021 00:55:17 +0100

journey planning services begins to include real time traffic forecast features in order to compute more accurate routing along the journey, adaptive traffic control systems can also benefit from this prediction so as to minimize traffic congestion. But these two systems dedicated to end user and road traffic management authorities could also benefits from other information, and particularly from parking availability prediction since cruising for parking spot represents a significant part of urban traffic: when looking for a parking, drivers must guess where to go, and if they are wrong, may face long distances to find the next location, resulting in considerable time loss and a worsening of traffic congestion. We focus on the simultaneous prediction of traffic and parking availability. Our approach relay on machine learning techniques and more precisely on representation learning methods: each road and car-park is represented by a vector in a common large dimensional space which captures both structural and dynamical information about the observed phenomenon. Such a model is thus able to jointly capture the spatio-temporal correlations between parking and traffic resulting in a high performance prediction system. The results of our experiments on the Grand Lyon (France) urban area show the effectiveness of our approach compared to state of the art methods.

Electric Vehicles charging control based on future internet generic enablers

Scipedia content — Fri, 29 Jan 2021 00:52:45 +0100

In this paper a rationale for the deployment of Future Internet based applications in the field of Electric Vehicles (EVs) smart charging is presented. The focus is on the Connected Device Interface (CDI) Generic Enabler (GE) and the Network Information and Controller (NetIC) GE, which are recognized to have a potential impact on the charging control problem and the configuration of communications networks within reconfigurable clusters of charging points. The CDI GE can be used for capturing the driver feedback in terms of Quality of Experience (QoE) in those situations where the charging power is abruptly limited as a consequence of short term grid needs, like the shedding action asked by the Transmission System Operator to the Distribution System Operator aimed at clearing networks contingencies due to the loss of a transmission line or large wind power fluctuations. The NetIC GE can be used when a master Electric Vehicle Supply Equipment (EVSE) hosts the Load Area Controller, responsible for managing simultaneous charging sessions within a given Load Area (LA); the reconfiguration of distribution grid topology results in shift of EVSEs among LAs, then reallocation of slave EVSEs is needed. Involved actors, equipment, communications and processes are identified through the standardized framework provided by the Smart Grid Architecture Model (SGAM).

Comment: To appear in IEEE International Electric Vehicle Conference (IEEE IEVC 2014)

A Novel Approach to Automated Merge 4D Arrival Trajectories for Multi-parallel Runways

Scipedia content — Fri, 29 Jan 2021 00:41:53 +0100

International audience; This paper reports on the research status of automated merging 4D trajectories for multi-parallel runwaysoperations in complex terminal area. In order to simultaneously reduce delay and increase capacity in metropolis airportwith multi-parallel runways, based on the classic Point-Merge route structure, a novel Multiple-Points-Merge (M-PM)route system is firstly proposed. It consists of multi-layers on the sequencing legs for dierent categories of aircraftwith H,Mand L, and a M-PM system for Beijing Capital international airport is built with lazy “8” topology. After that,a multiple-objectives function is discussed for this aircraft scheduling problem, operational constraints are analyzed indetail, a modelling strategy with sliding time window and simulated annealing algorithm is proposed for solving thisreal-time scheduling and sequencing landing problem. According to the relationship between aircraft entry time andthe position of sliding time window, all arrival aircraft are firstly classified into 4 dierent status: planned, ongoing,active, and completed, and then in the sliding time window the aircraft with active or ongoing status are optimized withre-sequence and conflict detection and resolution (CD&R) process. Conflict detection (CD) is based on pairwise formto detect separation infringement between aircraft. There are two types of conflict, catching up conflict and convergingconflict. Conflict resolution (CR) solve the detected horizontal conflict with speed adjustment, slot time control, andturning time control technique. In a future work, this novel M-PM system will be evaluated with real operational data.

Automatic Design of Aircraft Arrival Routes with Limited Turning Angle

Scipedia content — Fri, 29 Jan 2021 00:41:37 +0100

We present an application of Integer Programming to the design of arrival routes for aircraft in a Terminal Maneuvering Area (TMA). We generate operationally feasible merge trees of curvature-constrained routes, using two optimization criteria: (1) total length of the tree, and (2) distance flown along the tree paths. The output routes guarantee that the overall traffic pattern in the TMA can be monitored by air traffic controllers; in particular, we keep merge points for arriving aircraft well separated, and we exclude conflicts between arriving and departing aircraft. We demonstrate the feasibility of our method by experimenting with arrival routes for a runway at Arlanda airport in the Stockholm TMA. Our approach can easily be extended in several ways, e.g., to ensure that the routes avoid no-fly zones.

THE COMPARISON OF PUBLIC ROAD AND RAILWAY TRANSPORT COSTS

Scipedia content — Fri, 29 Jan 2021 00:38:27 +0100

This article compares the costs of public road and rail regional passenger transport in the district of Pardubice. The article contains the differences in unit costs between two means of transport, the objective point of view of the road and rail transport costs in the Pardubice region. The topic of solution is the classification of the differences in costs for road and rail passenger transport, because road transport does not include costs for road infrastucture and travel reimbursement for the use of other infrastructure. Příspěvek řeší porovnání nákladů na veřejnou silniční a železniční regionální osobní dopravu v Pardubickém kraji. Bude provedena analýza nákladů na silniční a železniční osobní dopravu, vymezen rozdíl v nákladovosti obou druhů dopravy, analýza jednotkových nákladů na dopravní výkon, objektivizace pohledu na nákladovost silniční a železniční dopravy v Pardubickém kraji. Předmětem řešení bude identifikace rozdílu v nákladech u silniční a železniční osobní dopravy, protože v silniční dopravě se nezapočítávají náklady na dopravní a cestu úhrada za použití ostatní infrastruktury.

A Jump-Linear Model based Sensitivity Study for Optimal Air Traffic Flow Management under Weather Uncertainty

Scipedia content — Fri, 29 Jan 2021 00:35:24 +0100

In this paper, we develop an analytical approach to planning air traffic flow management (TFM) strategies under uncertain weather. To do that, we model the dynamics of an air traffic flow under uncertain weather as a discrete jump-linear system, which enacts the tracking of transient traffic congestion statistics. We then conduct a sensitivity analysis of traffic congestion to disturbances introduced by mean inflow rate and flow restriction constraint. The integrated framework of jump-linear modeling and sensitivity analysis permits optimal planning for flow redistribution and flow restriction redesign. We demonstrate the design procedure through an example of a major flow splitting into multiple flows that enter a bank of weather zones.

The effect of electromagnetic fields due to hv line on the parallel pipeline

Scipedia content — Fri, 29 Jan 2021 00:35:09 +0100

The effects of electromagnetic fields(EMF) due to high voltage line on the parallel pipeline are not a common issue nowadays. The EMF will bring up some pipeline problems and safety issues. There are only a few of previous studies about EMF effects consider in the lightning fault parameter and study in term of currents. This means the EMF effect of the transmission line to the pipeline still not completed. A study has been carried out to determine the effect of electromagnetic field in term of voltage and current of the shared corridor between the transmission tower and the pipeline. This study is simulated by using ANSYS Maxwell software. The induced voltage obtained is in the range of 2.6089V to 4.7723V which within the maximum acceptable value (15V) of IEEE 80-2000 standards. The induced current obtained is in the range of 3.1893nA to 61.4640 nA. Besides, mitigation is also discussed.

OpenSky: A swiss army knife for air traffic security research

Scipedia content — Fri, 29 Jan 2021 00:34:52 +0100

The Automatic Dependent Surveillance - Broadcast (ADS-B) protocol is one of the key components of the next generation air transportation system. Since ADS-B will become mandatory by 2017 in the European airspace, it is crucial that aspects such as its security and privacy are promptly investigated by the research community. However, as expensive specialized equipment was previously necessary to collect real-world data on a large scale, such data has not been freely accessible until now. To enable researchers around the world to conduct experimental studies based on real air traffic data, we have created OpenSky, a participatory sensor network for air traffic research. In this paper, we describe the setup and capabilities of OpenSky, and detail some of the research into air traffic security that we have conducted using OpenSky.

Integration of dynamic weather routes automation with air/ground data communications

Scipedia content — Fri, 29 Jan 2021 00:33:23 +0100

The Dynamic Weather Routes (DWR) tool continuously and automatically analyzes airborne flights in en route airspace to identify flights where a route correction could save significant flight time and still avoid weather. A partnership between NASA, American Airlines (AA), and the FAA has enabled testing of DWR in real-world air traffic operations. En route Data Communications (Data Comm) could significantly reduce the controller and pilot workload needed to communicate DWR route changes under today's voice-based operations and thereby enable more timely and frequent high-value corrections to weather avoidance routes. Sample data from the DWR trial at AA illustrate how Data Comm could improve DWR operations. Two operating concepts that integrate DWR with Data Comm are described: (1) route corrections are initiated by air traffic control and implemented using Airborne Reroutes and Data Comm, and (2) route corrections are initiated by the dispatcher and pilot and implemented via Data Comm. Both concepts align with Federal Aviation Administration (FAA) plans for implementation of Data Comm in en route airspace.

Determination of Necessary and Sufficient Operational Conditions of The Sleeve-Type Bearings in Autonomous Power Plants of Ormat Type Under Conditions of Siberia and the Far East

Scipedia content — Fri, 29 Jan 2021 00:32:36 +0100

The analysis of integral reliability characteristics for autonomous energy sources in gas pipelines of Russia is carried out. The reasons of the most frequent failures are determined. Recommendations for increase of integral reliability characteristics for autonomous energy sources are formulated.

Detection and recognition of road markings in panoramic images

Scipedia content — Fri, 29 Jan 2021 00:31:43 +0100

The detection of road lane markings has many practical applications, such as advanced driver assistance systems and road maintenance. In this paper we propose an algorithm to detect and recognize road lane markings from panoramic images. Our algorithm consists of four steps. First, an inverse perspective mapping is applied to the image, and the potential road markings are segmented based on their intensity difference compared to the surrounding pixels. Second, we extract the distance between the center and the boundary at regular angular steps of each considered potential road marking segment into a feature vector. Third, each segment is classified using a Support Vector Machine (SVM). Finally, by modeling the lane markings, previous false positive detected segments can be rejected based on their orientation and position relative to the lane markings. Our experiments show that the system is capable of recognizing \\(93\\,\\%\\), \\(95\\,\\%\\) and \\(91\\,\\%\\) of striped line segments, blocks and arrows respectively, as well as \\(94\\,\\%\\) of the lane markings.

Managing an urban transport system in enhancing the area stability

Scipedia content — Fri, 29 Jan 2021 00:29:04 +0100

© Copyright 2016 by SCITEPRESS - Science and Technology Publications, Lda. All rights reserved.The urbanized mankind is faced with vulnerability of urban systems, migration and concentration of population, low quality of habitat, loss of fertile land, and necessity of waste disposal. In large cities, a significant contribution to atmospheric pollution with sulphur dioxide, nitrogen and carbon oxides, and industrial dust comes from the motor transport. The motor traffic growth inevitably affects the human health by causing road and transport traumatism, respiratory diseases and diseases caused by physical inactivity. The proposed solution is based on optimization of a city transport system parameters. This was achieved by via simulation modelling taking into account a large number of parameters, both within and outside the system, many of the latter being stochastic. The recommendations include rearranging of the public transport routes and changing over to vehicles running on gas motor fuel.

How Do Layered Airspace Design Parameters Affect Airspace Capacity and Safety?

Scipedia content — Fri, 29 Jan 2021 00:23:42 +0100

ce structure can be used as a procedural mechanism for a priori separation and organization of en-route air traffic. Although many studies have explored novel structuring methods to increase en-route airspace capacity, the relationship between the level of structuring of traffic and airspace capacity is not well established. To better understand the influence of traffic structure on airspace capacity, in this research, four airspace concepts, representing discrete points along the dimension of structure, were compared using large-scale simulation experiments. By subjecting the concepts to multiple traffic demand scenarios, the structure-capacity relationship was inferred from the effect of traffic demand variations on safety, efficiency and stability metrics. These simulations were performed within the context of a future personal aerial transportation system, and considered both nominal and non-nominal conditions. Simulation results suggest that the structuring of traffic must take into account the expected traffic demand pattern to be beneficial in terms of capacity. Furthermore, for the heterogeneous, or uniformly distributed, traffic demand patterns considered in this work, a decentralized layered airspace concept, in which each altitude band limited horizontal travel to within a predefined heading range, led to the best balance of all the metrics considered.

A Multi-Perspective View on Human-Automation Interactions in Aviation

Scipedia content — Fri, 29 Jan 2021 00:20:21 +0100

Part 3: Specific Contexts; International audience; Control mechanisms for the evolving potential of autonomous systems are not yet sufficiently established. However, there is a need for control to be allocated throughout organisational and institutional levels of society in order to manage increasing complexities. This study, which applies to the domain of Air Traffic Management (ATM), aims s to gauge stakeholders’ attitudes at an organisational level in order to lay the foundations for an easier identification of the challenges and paths to improvements in this industry. Using Grounded Theory (GT), the study maps and interprets workshop data and questionnaires gathered to elicit professionals’ views on automation in the aviation industry. The themes identified, which resonate with all those reviewed in the literature, will form the basis for the construction of a checklist and survey of automation issues expressed at an organisational level of control.

Hybrid SDN architecture for resource consolidation in MPLS networks

Scipedia content — Fri, 29 Jan 2021 00:13:59 +0100

This paper proposes a methodology for resource"br/"consolidation towards minimizing the power consumption in a"br/"large network, with a substantial resource overprovisioning. The"br/"focus is on the operation of the core MPLS networks. The"br/"proposed approach is based on a software defined networking"br/"(SDN) scheme with a reconfigurable centralized controller, which"br/"turns off certain network elements. The methodology comprises"br/"the process of identifying time periods with lower traffic demand;"br/"the ranking of the network elements, based on their utilization"br/"and criticality; the rerouting of the traffic off the least utilized"br/"elements; and finally, the switching off of the appropriate nodes"br/"or links. An algorithm for traffic rerouting, based on the MPLS"br/"traffic engineering techniques is proposed and its performance is"br/"evaluated in terms of the achieved energy efficiency in"br/"accordance with predefined connectivity and quality of service"br/"constraints.

Aircraft 4D trajectories planning under uncertainties

Scipedia content — Fri, 29 Jan 2021 00:00:36 +0100

International audience; To sustain the rapidly increasing air traffic demand, the future air traffic management system will rely on a concept, called Trajectory-Based Operations (TBO), that will require aircraft to follow an assigned 4D trajectory (time-constrained trajectory) with high precision. TBO involves separating aircraft via strategic (long-term) trajectory deconfliction rather than the currently-practicing tactical (short-term) conflict resolution. In this context, this paper presents a strategic 4D aircraft trajectory planning approach aiming at minimizing interaction between aircraft trajectories for a given day. The proposed methodology allocates an alternative departure time, a horizontal flight path, and a flight level to each flight at a country and a continent scale. Uncertainties of aircraft position and arrival time on its curvilinear abscissa are taken into account in the trajectory planning process. The proposed approach optimizes the 4D trajectory of each aircraft so as to minimize the interaction between trajectories. A hybrid-metaheuristic optimization algorithm has been developed to solve this large-scale mixed-variable optimization problem. The algorithm is implemented and tested with real air traffic data taking into account uncertainty over the French and the European airspace for which a conflict-free and robust 4D trajectory plan is produced.

Signal control in a congested traffic area

Scipedia content — Thu, 28 Jan 2021 23:53:22 +0100

The most travel delays in daily trips in modern large urban areas take place primarily at signal-controlled junctions due to regular interruption by alternating traffic lights. Therefore in urban traffic control road networks alleviation increasing of traffic congestion at signalized junctions becomes one of the most significant issues, facing decision makers at various levels of management. This paper is devoted to development of methodological tools to cope with problem of settings traffic signals for congested transportation network. The global traffic control system is assumed to define timing parameters of signals for the whole transportation network. Users of network are believed to react on any fixed signal setting, assigning according to user-equilibrium of Wardrop. Thus, the global optimal signal settings problem under user network equilibrium conditions is formulated as bi-level optimization program. When travel time is modeled by modified linear BPR cost function, the user-equilibrium flow patterns for two intersecting networks of parallel routes could be obtained as explicit condition of the lower programming level.

HybridTE: Traffic Engineering for Very Low-Cost Software-Defined Data-Center Networks

Scipedia content — Thu, 28 Jan 2021 23:50:21 +0100

The size of modern data centers is constantly increasing. As it is not economic to interconnect all machines in the data center using a full-bisection-bandwidth network, techniques have to be developed to increase the efficiency of data-center networks. The Software-Defined Network paradigm opened the door for centralized traffic engineering (TE) in such environments. Up to now, there were already a number of TE proposals for SDN- controlled data centers that all work very well. However, these techniques either use a high amount of flow table entries or a high flow installation rate that overwhelms available switching hardware, or they require custom or very expensive end-of-line equipment to be usable in practice. We present Hybrid TE, a TE technique that uses (uncertain) information about large flows. Using this extra information, our technique has very low hardware requirements while maintaining better performance than existing TE techniques. This enables us to build very low-cost, high performance data-center networks.

The Impact of Submarine Slides on Pipelines: Outcomes from the COFS-MERIWA JIP

Scipedia content — Thu, 28 Jan 2021 23:48:48 +0100

PerSEE: A central sensors fusion electronic control unit for the development of perception-based ADAS

Scipedia content — Thu, 28 Jan 2021 23:46:21 +0100

utomated vehicles and Advanced Driver Assistance Systems (ADAS) face a variety of complex situations that are dealt with numerous sensors for the perception of the local driving area. Going forward, we see an increasing use of multiple, different sensors inputs with radar, camera and inertial measurement the most common sensor types. Each system has its own purpose and either displays information or performs an activity without consideration for any other ADAS systems, which does not make the best use of the systems. This paper presents an embedded real-time system to combine the attributes of obstacles, roadway and ego-vehicle features in order to build a collaborative local map. This embedded architecture is called PerSEE: a library of vision-based state-of-the-art algorithms was implemented and distributed in processors of a main fusion electronic board and on smart-cameras board. The embedded hardware architecture of the full PerSEE platform is detailed, with block diagrams to illustrate the partition of the algorithm on the different processors and electronic boards. The communications interfaces as well as the development environment are described.

Modelling Based Radiography for NDE of Subsea Pipelines

Scipedia content — Thu, 28 Jan 2021 23:42:28 +0100

This work presents the use of limited experimental measurements to develop a set of calibrated simulation parameters that can then be used for reliable simulation of subsea pipeline inspections. The modelling software aRTist is used as the simulation tool, and the calibration is through comparison with experimental images of a well characterised sample in a water tank. Image quality parameters such as signal-to-noise ratio, contrast and basic spatial resolution are compared with the aim of matching simulated values to experimental results. Currently the model is partially calibrated, with signal-to-noise ratio successfully matched while differences are still found in contrast-to-noise ratio comparisons. This means that measurements depending on absolute intensity are not accurate enough in the simulation at this stage. However, the simulation is found to be accurate for wall thickness measurements in tangential images, which are not based on absolute intensity, with simulated and experimental cases producing similar results.

On the Complexity of Congestion Free Routing in Transportation Networks

Scipedia content — Thu, 28 Jan 2021 23:38:10 +0100

Traffic congestion has been proven a difficult problem to tackle, particularly in big cities where the number of cars are steadily increasing while the infrastructure remains stagnant. Several approaches have been proposed to alleviate the effects of traffic congestion, however, so far congestion is still a big problem in most cities. In this work we investigate a new route reservation approach to address the problem which is motivated by air traffic control. This paper formulates the route reservation problem under different assumptions and examines the complexity of the resulting formulations. Two waiting strategies are investigated, (i) vehicles are allowed to wait at the source before they start their journey, and (ii) they are allowed to wait at every road junction. Strategy (i) though more practical to implement, results to an NP-complete problem while strategy (ii) results to a problem that can be solved in polynomial time but it is not easily implemented since the infrastructure does not have adequate space for vehicles to wait until congestion downstream is cleared. Finally, a heuristic algorithm (based on time-expanded networks) is derived as a solution to both proposed waiting strategies. © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works C. Menelaou, P. Kolios, S. Timotheou and C. Panayiotou, "On the Complexity of Congestion Free Routing in Transportation Networks," 2015 IEEE 18th International Conference on Intelligent Transportation Systems, Las Palmas, 2015, pp. 2819-2824. doi: 10.1109/ITSC.2015.453

Document type: Conference object

Design of an Ecological Flow-based Interface for 4D Trajectory Management in Air Traffic Control

Scipedia content — Thu, 28 Jan 2021 23:34:02 +0100

The concept of trajectory-based operations as proposed by SESAR and NextGen seeks to increase airspace efficiency and capacity by introducing time as an explicit control variable. Such form of operations lean heavily on the introduction of higher levels of automation to support the human air traffic controller in performing this new task. In previous research, and following the ecological interface design paradigm, a constraint-based decision support tool has been developed to visualize safe and unsafe fields of travel for rerouting the 4D trajectories of individual aircraft. A human-in-the-loop experiment showed that although the interface visualizes the boundaries between safe and unsafe actions, the quality of control in terms of robustness was mainly dependent on the level of expertise of the human controller. Following these findings, the goal of this study has been twofold: 1) to explicitly integrate the attributes of robust control actions into the constraint-based visualization, and 2) to enable flow-based (multi-aircraft) operations with the decision-support tool which is more in line with the mental model of expert controllers. As a result, a metric for the evaluation of robustness has been developed and three different types of structure-based control abstractions have been identified which have been integrated into the tool. Future work will focus on a human-in-the-loop experiment in order to evaluate the effectiveness of these two new additions.

Taxi Time Prediction at Charlotte Airport Using Fast-Time Simulation and Machine Learning Techniques

Scipedia content — Thu, 28 Jan 2021 23:32:03 +0100

urate taxi time prediction is required for enabling efficient runway scheduling that can increase runway throughput and reduce taxi times and fuel consumptions on the airport surface. Currently NASA and American Airlines are jointly developing a decision-support tool called Spot and Runway Departure Advisor (SARDA) that assists airport ramp controllers to make gate pushback decisions and improve the overall efficiency of airport surface traffic. In this presentation, we propose to use Linear Optimized Sequencing (LINOS), a discrete-event fast-time simulation tool, to predict taxi times and provide the estimates to the runway scheduler in real-time airport operations. To assess its prediction accuracy, we also introduce a data-driven analytical method using machine learning techniques. These two taxi time prediction methods are evaluated with actual taxi time data obtained from the SARDA human-in-the-loop (HITL) simulation for Charlotte Douglas International Airport (CLT) using various performance measurement metrics. Based on the taxi time prediction results, we also discuss how the prediction accuracy can be affected by the operational complexity at this airport and how we can improve the fast time simulation model before implementing it with an airport scheduling algorithm in a real-time environment.

Generation of ultra-realistic synthetic echocardiographic sequences to facilitate standardization of deformation imaging

Scipedia content — Thu, 28 Jan 2021 23:24:57 +0100

© 2015 IEEE. Despite the overwhelming availability of techniques for computation of cardiac deformation and strain with 2D echocardiography, their widespread dissemination in clinical practice is still held back by the reported low reproducibility between different solutions. This can in part be attributed to the lack of a solid and open quality assurance framework to assess and compare their performance. Building upon our previous work, we present here a new pipeline for the benchmarking of such algorithms making use of realistic 2D synthetic sequences. While the synthetic motion is fully controlled by a computational heart model, the visual appearance is extremely similar to a real ultrasound recording. The pipeline is used to generate an initial library of four sequences. ispartof: pages:756-759 ispartof: IEEE International Symposium on Biomedical Imaging vol:2015-July pages:756-759 ispartof: IEEE International Symposium on Biomedical Imaging location:New York City. US date:May - May 2015 status: published

Measuring the long-distance accessibility of Italian cities

Scipedia content — Thu, 28 Jan 2021 23:23:39 +0100

Long-distance accessibility is a crucial element for economic development and for territorial cohesion. To be revealing, however, a measure of accessibility must not only consider the distance or travel time of a single mode, but should include the fares, the frequency and the interchanges of all available modes. The paper aims to address whether and where there is an accessibility problem between Italian regions, through a comprehensive measure of accessibility covering the entire Italian territory. The measure used in the paper is potential accessibility, with an exponential decay impedance function. Different from similar studies, this one gives a more in-depth definition of impedance parameters due to the availability of a transport model that includes the entire Italian long-distance supply (roads, coaches, long-distance rail services, air services, and ferries). The opportunities at destination are proxied by population, and private and public sector employees. The main outputs are detailed maps of accessibility that are significantly more realistic than using simple infrastructure indicators or single-mode measures. In addition, some policy conclusions are drawn in terms of past and future investment policies.

The implications of automobile dependency in Abu Dhabi city

Scipedia content — Thu, 28 Jan 2021 23:20:37 +0100

Global trends indicate that automobile dependency is increasing at a tremendous pace especially in developing countries – much faster than the provision of roadway and transport infrastructure. Furthermore, research shows both car use and ownership tend to increase with economic development and growth. Abu Dhabi City is a typical example of a fast growing (economically, population and wealth) city, where car ownership is growing at an annual rate of 24% and most journeys are made by car. Transport policy makers in Abu Dhabi face an uphill challenge as they try on the one hand to develop a comprehensive multi-modal transport network that includes various elements of mass transit systems and on the other, to deal with an increasing car dependency. The externalities associated with a car dependent society is currently being felt in Abu Dhabi and the region in general, with the rise of congestion, health problems associated with lack of physical mobility, accidents and environment deterioration. This paper assesses the impacts of automobile dependency in Abu Dhabi city, and includes how Abu Dhabi compares with similar international cities, outlines key challenges facing Abu Dhabi while taking into account the unique characteristics of Abu Dhabi; and finally concludes with key recommendations that Abu Dhabi can employ to overcome automobile dependency, in order to realize the long-term aspirations of a world-class city with a well-integrated multi-modal transport system.

A Cleanup Algorithm for Implementing Storage Constraints in Scientific Workflow Executions

Scipedia content — Thu, 28 Jan 2021 23:19:05 +0100

Scientific workflows are often used to automate large-scale data analysis pipelines on clusters, grids, and clouds. However, because workflows can be extremely data-intensive, and are often executed on shared resources, it is critical to be able to limit or minimize the amount of disk space that workflows use on shared storage systems. This paper proposes a novel and simple approach that constrains the amount of storage space used by a workflow by inserting data cleanup tasks into the workflow task graph. Unlike previous solutions, the proposed approach provides guaranteed limits on disk usage, requires no new functionality in the underlying workflow scheduler, and does not require estimates of task runtimes. Experimental results show that this algorithm significantly reduces the number of cleanup tasks added to a workflow and yields better workflow makespans than the strategy currently used by the Pegasus Workflow Management System.

Acoustic energy transmission in cast iron pipelines

Scipedia content — Thu, 28 Jan 2021 23:14:57 +0100

In this paper we propose acoustic power transfer as a method for the remote powering of pipeline sensor nodes. A theoretical framework of acoustic power propagation in the ceramic transducers and the metal structures is drawn, based on the Mason equivalent circuit. The effect of mounting on the electrical response of piezoelectric transducers is studied experimentally. Using two identical transducer structures, power transmission of 0.33 mW through a 1 m long, 118 mm diameter cast iron pipe, with 8 mm wall thickness is demonstrated, at 1 V received voltage amplitude. A nearlinear relationship between input and output voltage is observed. These results show that it is possible to deliver significant power to sensor nodes through acoustic waves in solid structures. The proposed method may enable the implementation of acousticpowered wireless sensor nodes for structural and operation monitoring of pipeline infrastructure.

Research sucker on load-unload robot special for electric power metering device testing

Scipedia content — Thu, 28 Jan 2021 23:08:11 +0100

Electricity metering equipment automatic testing detection pipeline has been widely used in most provincial company of the State Grid in the past two years. Sichuan electric power corpora- tion metering center first developed a fully compatible pipelines, the compatibility of robot is one of the difficulties need to solve. According to the actual operation situation after the pipeline fully put into production, this paper analyzes the design and capacity of load-unloading robot special for electric energy metering equipment. Firstly, it introduces the current research status of the load- unload industrial robot, do a comparison between the existing robot execution ends in the electric power industry and the new design compatible sucker end-effector, and then introduces the struc- tural design of robot, the design parameters of sucker, and the running process and the beats of ro- bot. Through actual production operation, it is shown that the sucker robot special for the electric energy metering equipment can achieve precision several kinds equipments, which has a good ap- plication prospect.

Reducing set-associative L1 data cache energy by early load data dependence detection (ELD"sup"3"/sup")

Scipedia content — Thu, 28 Jan 2021 22:59:00 +0100

Fast set-associative level-one data caches (L1 DCs) access all ways in parallel during load operations for reduced access latency. This is required in order to resolve data dependencies as early as possible in the pipeline, which otherwise would suffer from stall cycles. A significant amount of energy is wasted due to this fast access, since the data can only reside in one of the ways. While it is possible to reduce L1 DC energy usage by accessing the tag and data memories sequentially, hence activating only one data way on a tag match, this approach significantly increases execution time due to an increased number of stall cycles. We propose an early load data dependency detection (ELD3) technique for in-order pipelines. This technique makes it possible to detect if a load instruction has a data dependency with a subsequent instruction. If there is no such dependency, then the tag and data accesses for the load are sequentially performed so that only the data way in which the data resides is accessed. If there is a dependency, then the tag and data arrays are accessed in parallel to avoid introducing additional stall cycles. For the MiBench benchmark suite, the ELD3 technique enables about 49% of all load operations to access the L1 DC sequentially. Based on 65-nm data using commercial SRAM blocks, the proposed technique reduces L1 DC energy by 13%.

Rail Surface Measurement And Multi-Scale Modeling Of Wheel-Rail Contact

Scipedia content — Thu, 28 Jan 2021 22:55:57 +0100

Published (Publication status)

A crowdsourcing solution to collect e-commerce reverse flows in metropolitan areas

Scipedia content — Thu, 28 Jan 2021 22:47:57 +0100

International audience; On the forward side, the growth of E-commerce in recent years substantially generates additional packets and parcels for distribution; meanwhile, on the reverse side, collecting returned goods is also becoming a preoccupation of sustainability, especially in metropolitan areas. Inspired by the concepts of crowdsourcing and the Physical Internet, in this paper, we propose an innovative solution that seeks to exploit the extra loading capacity and constant mobility from taxis in metropolitan areas to collect and delivery the e-commerce returns from final consumption points back to retailers. We assume that, on one hand, e-retailers will have incentive to outsource this task; on the other hand, taxi drivers will also be motivated because they can earn a little extra money from the shipments that they have fulfilled. As an alternative to the traditional ways, the solution proposed is more sustainable because it could simultaneously reduce the economical (pickup and transportation costs), environmental (CO 2 emissions, energy consumption, traffic congestion in city), and social (the wastes of the impulse buying, reduced incitation of online shopping) impacts resulted from reverse flows management in metropolitan areas. As the first qualitative and quantitative study of the concept, this paper uses open databases of taxi GPS traces and locations of shops in a large city in China for investigating the feasibility and viability of the solution proposed. Two collection strategies are proposed and evaluated by an optimization-based simulation model. The results generate several useful insights to the implementability and managerial issues of the concept.

Comparison of numerical predictions with CO2 pipeline release datasets of relevance to carbon capture and storage applications

Scipedia content — Thu, 28 Jan 2021 22:40:25 +0100

Predicting the correct multi-phase fluid flow behaviour during the discharge process in the near-field of sonic CO2 jets is of particular importance in assessing the risks associated with transport aspects of carbon capture and storage schemes, given the very different hazard profiles of CO2 in the gaseous and solid states. In this paper, we apply our state-of-the-art mathematical model implemented in an efficient computational method to available data. Compared to previous applications, an improved equation of state is used. We also compare to all the available data, rather than just subsets as previously, and demonstrate both the improved performance of the fluid flow model and the variation between the available datasets. The condensed phase fraction at the vent, puncture or rupture release point is revealed to be of key importance in understanding the near-field dispersion of sonic CO2.

Wind Information Uplink to Aircraft Performing Interval Management Operations

Scipedia content — Thu, 28 Jan 2021 22:39:34 +0100

Interval Management (IM) is an ADS-B-enabled suite of applications that use ground and flight deck capabilities and procedures designed to support the relative spacing of aircraft (Barmore et al., 2004, Murdoch et al. 2009, Barmore 2009, Swieringa et al. 2011; Weitz et al. 2012). Relative spacing refers to managing the position of one aircraft to a time or distance relative to another aircraft, as opposed to a static reference point such as a point over the ground or clock time. This results in improved inter-aircraft spacing precision and is expected to allow aircraft to be spaced closer to the applicable separation standard than current operations. Consequently, if the reduced spacing is used in scheduling, IM can reduce the time interval between the first and last aircraft in an overall arrival flow, resulting in increased throughput. Because IM relies on speed changes to achieve precise spacing, it can reduce costly, low-altitude, vectoring, which increases both efficiency and throughput in capacity-constrained airspace without negatively impacting controller workload and task complexity. This is expected to increase overall system efficiency. The Flight Deck Interval Management (FIM) equipment provides speeds to the flight crew that will deliver them to the achieve-by point at the controller-specified time, i.e., assigned spacing goal, after the target aircraft crosses the achieve-by point (Figure 1.1). Since the IM and target aircraft may not be on the same arrival procedure, the FIM equipment predicts the estimated times of arrival (ETA) for both the IM and target aircraft to the achieve-by point. This involves generating an approximate four-dimensional trajectory for each aircraft. The accuracy of the wind data used to generate those trajectories is critical to the success of the IM operation. There are two main forms of uncertainty in the wind information used by the FIM equipment. The first is the accuracy of the forecast modeling done by the weather provider. This is generally a global environmental prediction obtained from a weather model such as the Rapid Refresh (RAP) from the National Centers for Environmental Prediction (NCEP). The weather forecast data will have errors relative to the actual, or truth, winds that the aircraft will encounter. The second source of uncertainty is that only a small subset of the forecast data can be uplinked to the aircraft for use by the FIM equipment. This results in loss of additional information. The Federal Aviation Administration (FAA) and RTCA are currently developing standards for the communication of wind and atmospheric data to the aircraft for use in NextGen operations. This study examines the impact of various wind forecast sampling methods on IM performance metrics to inform the standards development.

Leakage detection in galvanized iron pipelines using ensemble empirical mode decomposition analysis

Scipedia content — Thu, 28 Jan 2021 22:29:35 +0100

There are many numbers of possible approaches to detect leaks. Some leaks are simply noticeable when the liquids or water appears on the surface. However many leaks do not find their way to the surface and the existence has to be check by analysis of fluid flow in the pipeline. The first step is to determine the approximate position of leak. This can be done by isolate the sections of the mains in turn and noting which section causes a drop in the flow. Next approach is by using sensor to locate leaks. This approach are involves strain gauge pressure transducers and piezoelectric sensor. the occurrence of leaks and know its exact location in the pipeline by using specific method which are Acoustic leak detection method and transient method. The objective is to utilize the signal processing technique in order to analyse leaking in the pipeline. With this, an EEMD method will be applied as the analysis method to collect and analyse the data.

Arrival Metering Precision Study

Scipedia content — Thu, 28 Jan 2021 22:29:14 +0100

This paper describes the background, method and results of the Arrival Metering Precision Study (AMPS) conducted in the Airspace Operations Laboratory at NASA Ames Research Center in May 2014. The simulation study measured delivery accuracy, flight efficiency, controller workload, and acceptability of time-based metering operations to a meter fix at the terminal area boundary for different resolution levels of metering delay times displayed to the air traffic controllers and different levels of airspeed information made available to the Time-Based Flow Management (TBFM) system computing the delay. The results show that the resolution of the delay countdown timer (DCT) on the controllers display has a significant impact on the delivery accuracy at the meter fix. Using the “10 seconds rounded” and “1 minute rounded” DCT resolutions resulted in more accurate delivery than “1 minute truncated” and were preferred by the controllers. Using the speeds the controllers entered into the fourth line of the data tag to update the delay computation in TBFM in high and low altitude sectors increased air traffic control efficiency and reduced fuel burn for arriving aircraft during time based metering.

The parcel industry in the spatial organization of logistics activities in the Paris Region: inherited spatial patterns and innovations in urban logistics systems

Scipedia content — Thu, 28 Jan 2021 22:23:47 +0100

The 9th International Conference on City Logistics, Tenerife, Iles Canaries, ESPAGNE, 17-/06/2015 - 19/06/2015; The aim of this paper is to study the location of the parcel industry, and its place in the spatial organization of logistics activities in the Paris Region. In particular, we wish to compare the location of the parcel industry to the location of other logistics activities. In order to do this, we review in part one the existing factors that determines the location of logistics activities. We use this literature review to draw initial conclusions on the distinctive characteristics of the parcel industry. In part two, we use existing data on the location of establishments in the Paris Region to study the dispersion of the parcel industry compared to the dispersion of other logistics activities. Finally, in part three, we provide a partial explanation for this difference: a spatial hysteresis of the big stakeholders of the parcel industry, and the emergence of innovative logistics solutions.

Document type: Conference object

Approach to simulation assessment of area-wide traffic calming in the context of sustainable development

Scipedia content — Thu, 28 Jan 2021 22:23:06 +0100

The introduction of traffic calming in city centre areas is one of the measures aimed at implementing the transport policy which is based on the principles of sustainable development. Traffic calming refers to a combination of road network planning and engineering measures to reduce negative effects of motor vehicle use and improve conditions for non-motorized street users. However, it should not be seen exclusively as a means of introducing traffic restrictions or reducing the speed limit. Comprehensive schemes of area-wide traffic calming result in a synergy effect improving not only traffic conditions but also liveability, environment, safety and the urban landscape. However, one has to emphasize that what is crucial for making use of the capabilities of a comprehensive traffic calming scheme is the proper preparation of the investment. Implementing the ideas of traffic calming should bring the best results in enhancing sustainable safety of drivers and pedestrians, improving the quality of urban life and reducing traffic flows and undesirable effects, such as traffic noise and pollutant emissions. The paper contains a literature review on impacts and effectiveness of area-wide traffic calming solutions. An exemplary approach illustrating how to include traffic calming zones in simulation modelling is also presented. The suggested approach involves the use of simulation tools in both micro and macro scale and tests with a driving simulator to assess the influence of traffic calming measures on speeds, travel times, route choices, modal split and therefore on the level of road safety, traffic noise and air pollution. The influence of individual measures examined at a microscopic level allows one to assess the functioning of the whole transport system at the macro level. This makes it possible to plan the transport service of the area, to reduce congestion and migration of disruptions onto other network links as well as to prepare a proper assessment of functional effectiveness of implemented solutions.

Delphi Analysis Method and Its Application in Qualitative Prediction of Aircraft Collision Unsafe Event for Air Traffic Control

Scipedia content — Thu, 28 Jan 2021 22:21:39 +0100

To predict the safety situation of air traffic control, it is inadequate to only use some quantitative prediction method, which can not take into account the knowledge and experience of the experts. We should also pay attention to the important role of some qualitative prediction method. Delphi analysis method based on the opinion and consultation of the experts is proposed to predict the unsafe events in the field of air traffic control. The example shows that Delphi analysis method can be used to solve the problem of safety prediction in air traffic control.

Techno-economic evaluation of electric vehicles as flexible load for providing grid services

Scipedia content — Thu, 28 Jan 2021 22:17:25 +0100

System operators use grid services to ensure grid stability and security. In liberalized energy markets, these services are made available through market tenders. Flexible generation and load representing a major part of these grid services. This paper presents the development of a Key Performance Indicator (KPI) based methodology and the evaluation undertaken during the field trial for the project sMobiliTy. The KPIs are developed and benchmarked by deriving generalized requirements through a wide range of grid services in multiple networks. The approach is used to assess and quantify the suitability of electric vehicle pools with respect to technical and market tendering requirements as well as network connection requirements for distributed devices.

Evaluation of Electric Vehicle Charging Controllability for Provision of Time Critical Grid Services

Scipedia content — Thu, 28 Jan 2021 22:06:46 +0100

Replacement of conventional generation by more stochastic renewable generation sources leads to reduction of inertia and controllability in the power system. This introduces the need for more dynamic regulation services. These faster services could potentially be provided by the growing number of electric vehicles. EVs are a fast responding energy resource with high availability. This work evaluates and experimentally shows the limits of EV charging controllability using widely supported IEC 61851 standard. The focus is put on EVs suitability for providing ancillary grid services with time critical requirements. Three different series produced EVs are tested. The experimental testing is done by using charging current controllability of built-in AC charger to provide a primary frequency regulation service with very dynamic input frequency. The results show that the controllability of most EVs is more than suitable for providing time critical grid services. Meanwhile, charging current ramping rates of recently produced EVs are potentially suitable to even provide synthetic inertia.

Toward the Development of a Low-Altitude Air Traffic Control Paradigm for Networks of Small, Autonomous Unmanned Aerial Vehicles

Scipedia content — Thu, 28 Jan 2021 21:58:21 +0100

To enable safe and efficient operation of a large number of Unmanned Aerial Vehicles (UAVs) as envisioned in future commercial operations, a novel networked-based air traffic control paradigm is needed to provide for autonomous route optimization and cooperation to enable deconfliction. This system would need to ensure deconfliction from nearby manned and unmanned operations and would need the capability to respond to unexpected close-proximity aircraft, known as interlopers. This network-based control paradigm will require that operators be able to oversee a network of cooperative and autonomous UAVs capable of maneuvering at low altitudes. Such a network would need new algorithms and increased autonomy to best support cooperative deconfliction and high level supervisory control, and one that also allows operators the ability to both understand local and global behavior of a network of UAVs. To this end, we propose a paradigm-shifting multi-layer distributed air traffic control concept focused on low altitude, high density UAV operations. This new architecture would include a group of analysts that perform a global analysis of the UAV network at a strategic level and more tactical, local controllers manipulating the UAV network, who are advised by the analysts. The proposed operational support system would include methods for the automatic identification of issues within the network, as well as a method for the automatic distribution of effective tasks to the most suitable personnel. This architecture would be a combination of current air traffic control techniques as well as those troubleshooting techniques found in other domains like network and cloud computing management.

Ontologies for nextgen avionics systems

Scipedia content — Thu, 28 Jan 2021 21:56:50 +0100

The Federal Aviation Administration (FAA) Next Generation Air Transportation System (NextGen) system incorporates many updates to aerospace technology including coordination of air traffic management (ATM), flight deck control, and avionics architectures. One such consideration is the need for ontologies. An ontology is a formal naming and definition of the types, properties, and interrelationships of the entities that exist (and persist) for a particular domain. In aviation, an ontology is needed to organize the variables to afford computations, instructions, and the relationships between parameters. For example Triples are used as Universal Resource Identifiers (URIs) in the case of {subject, predicate (verb), object}. The subject and object entities can be connected with the relationship predicate. Together, they are an event such as an ontology coordinating Notice to Airmen (NOTAM) flight weather information. In this paper, we explore the concepts of ontologies for applications to aerospace avionics as motivated by the NextGen and Single European Sky ATM Research (SESAR) standards.

Risk Evaluation of Gas Pipeline Based on Rough Set

Scipedia content — Thu, 28 Jan 2021 21:50:20 +0100

Gas is a flammable, explosive and high-pressure medium. Gas pipelines are passing through many different geographical conditions of changing natural environment with gas. Therefore, a lot of adverse consequences will be bought by the gas pipeline failure, however not all consequences have a great impact on assessment of the losses. The rough set theory is used to simplify the accident loss. In this paper, the accident loss of gas pipelines of the gas enterprise in one city taken as an example is evaluated and forecasted with the rough set theory, which can bring the scientific foundation for the managers management and decision.

Moving Car Detection and Model Recognition based on Deep Learning

Scipedia content — Thu, 28 Jan 2021 21:39:13 +0100

Vehicle analysis is an import task in many intelligent applications, such as automatic toll collection and driver assistance systems. Among these applications, moving car detection and model recognition are a challenging task due to the close appearance between car models. In this paper, we propose a framework to detect moving cars and its model based on deep learning. We first detect the moving car using frame difference; the resultant binary image is used to detect the frontal view of a car by a symmetry filter. The detected frontal view is used to identify a car based on deep learning with three layers of restricted Boltzmann machines (RBMs). Experiment results show that our proposed framework achieves favorable recognition accuracy.

From CAD to 3D Tracking — Enhancing & Scaling Model-Based Tracking for Industrial Appliances

Scipedia content — Thu, 28 Jan 2021 21:36:54 +0100

For Augmented Reality to succeed in industrial appliances, industries demand not only robust and reliable tracking techniques, but also a scalable and performant pipeline, that is easy-to-integrate within the existing data- and content environment and that enables vendors to create tracking solutions on their own. In our demo, we present recent advances of our model tracking pipeline and tracking technology, which on the one hand is easy use and easy to integrate, while on the other hand robust enough during difficult environmental conditions and which delivers high accuracy for the industrial domain. We showcase our results inside an AR-manual scenario.

Experimental and Numerical Study of Wave-Induced Backfilling Beneath Submarine Pipelines

Scipedia content — Thu, 28 Jan 2021 21:34:54 +0100

Through complementary experimental and numerical efforts, the present paper aims to make a significant contribution to the overall understanding of backfilling processes beneath submarine pipelines. For this purpose, we aim to simplify the experimental backfilling process to an elementary two-stage process: (1) initial scour induced by a pure current, followed by: (2) backfilling induced by pure waves. A steady current is introduced via a re-circulating pump, and is kept constant with a cross-sectional velocity of V = 0.48 m/s until an initial equilibrium scour depth, S0, is reached. Then, the current is stopped and waves (characterized by their Keulegan-Carpener number KC and Shields parameter θ)are introduced to initiate the backfilling process, which is maintained until a new equilibrium scour depth, Sf, is reached. The time at which waves are introduced will be denoted as t = 0. For the backfilling process both regular and irregular waves are used during the experiments. As a demonstration of the initiated two-stage (scour followed by backfilling) process, bed profiles based on video recordings from a case having KC = 9.7 and ϴ = 0.195,are depicted at selected stages in Figure 1. Figure 1(upper left) depicts the current-induced equilibrium scour hole in the near vicinity of the pipe at t = 0, with the profile approximated as the dashed red line. Similarly, Figure 1(upper right) depicts the new equilibrium scour profile (approximated as the full blue line) that has developed under wave-induced backfilling, corresponding to t = 60min. To ease comparison, the dashed red and full bluelines from these plots are additionally combined onto Figure 1 (bottom).The experimental campaign has additionally been complemented with similar numerical simulations (using regular waves), based on a fully-coupled hydrodynamicand morphodynamic CFD model (Jacobsen et al., 2014),extending previous pipeline scour-related applications ofFuhrman et al. (2014) and Larsen et al. (2016). Comparison of the numerical and experimental results demonstrate the ability of the CFD model to reasonably simulate the current-to-wave backfilling process, both interms of the achieved new wave induced equilibriumscour depths as well as the corresponding backfilling timescales. Figure 2 depicts a summary of both experimental and numerical backfilling time scale Tb versus Shields parameter θ. As can be seen, both experimental as well as numerical results match the regression equation:T"sub"b"/sub"=0.3 θ-"sup"5/3 "/sup"quite closely (solid line in Figure 2).

Risk-based Causal Modeling of Airborne Loss of Separation

Scipedia content — Thu, 28 Jan 2021 21:30:50 +0100

Maintaining safe separation between aircraft remains one of the key aviation challenges as the Next Generation Air Transportation System (NextGen) emerges. The goals of the NextGen are to increase capacity and reduce flight delays to meet the aviation demand growth through the 2025 time frame while maintaining safety and efficiency. The envisioned NextGen is expected to enable high air traffic density, diverse fleet operations in the airspace, and a decrease in separation distance. All of these factors contribute to the potential for Loss of Separation (LOS) between aircraft. LOS is a precursor to a potential mid-air collision (MAC). The NASA Airspace Operations and Safety Program (AOSP) is committed to developing aircraft separation assurance concepts and technologies to mitigate LOS instances, therefore, preventing MAC. This paper focuses on the analysis of causal and contributing factors of LOS accidents and incidents leading to MAC occurrences. Mid-air collisions among large commercial aircraft are rare in the past decade, therefore, the LOS instances in this study are for general aviation using visual flight rules in the years 2000-2010. The study includes the investigation of causal paths leading to LOS, and the development of the Airborne Loss of Separation Analysis Model (ALOSAM) using Bayesian Belief Networks (BBN) to capture the multi-dependent relations of causal factors. The ALOSAM is currently a qualitative model, although further development could lead to a quantitative model. ALOSAM could then be used to perform impact analysis of concepts and technologies in the AOSP portfolio on the reduction of LOS risk.

Experimental Investigation of Factors Influencing External Corrosion of Buried Pipes

Scipedia content — Thu, 28 Jan 2021 21:08:28 +0100

Corrosion is a serious concern for owners and managers of buried pipelines as it can cause time dependent structural degradation which adversely affects the service life of pipelines. Leaks or rupture caused by corrosion are commonly identified problems in buried metal pipelines which can lead for catastrophic failures causing significant socio-economic losses for consumers as well as water utilities. Despite the periodic inspection of these buried pipelines, the corrosion attack is still one of the major problems in almost every part of the world. Although the corrosion attack can manifest in both internal and external surfaces of pipes, the external corrosion has been reported as the root cause of failure for these pipes. Therefore, an understanding of the external corrosion mechanism and its contributing factors can bring significant insight for corrosion protection of newly installed pipes and maintaining the aged pipes. The current research presents an innovative approach to explore the effects of factors influencing external corrosion of buried metal pipes. The method showed effective outcomes for evaluating the coupled effect of soil pH and moisture on the external corrosion behavior of cast iron pipes buried in natural soil.

Aerodynamic Testing and Development of Sunswift eVe

Scipedia content — Thu, 28 Jan 2021 21:01:42 +0100

The current understanding of the aerodynamic performance of Sunswift’s solar-electric race car eVe is limited, despite the design and manufacture of the vehicle in 2012-13. This paper describes an investigation into the aerodynamic behaviour of the vehicle and details the successive design and development of drag minimisation strategies. A study of the external airflow around the vehicle was undertaken through a computational fluid dynamics analysis, with validation offered through the results of real-world track testing. Particular reference is made to the Sunswift team’s successful long-range electric vehicle land speed record attempt on 23 July 2014. A predicted 10% reduction in drag has been achieved through external bodywork modifications as described within this paper. Recommendations for the design of low drag vehicles are also presented, with relation made to the future of sustainable transport.

Modelling heat transfer in flashing CO2fluid upon rapid decompression in pipelines

Scipedia content — Thu, 28 Jan 2021 20:53:20 +0100

urate prediction of transient releases of CO2 fluid from high-pressure transportation pipelines is important for the hazard assessment of such pipelines and the planning of their routine venting procedures. The accurate prediction of the fluid phase content, mass flow rate, pressure and temperature is key to the emergency response strategy or the vent pipe design, and is fundamental to the pipeline design and material selection for fracture control. Commonly to calculate releases of flashing fluids, such as hydrocarbons, from high-pressure vessels and pipelines, the simplifying assumption of a homogeneous equilibrium mixture (HEM) is applied. While this approach has proven to be robust for hydrocarbon mixtures, its validity is limited to inertia-dominant flows where the vapour and liquid-phases are well mixed. In the case of CO2 fluid, the widely different densities of the vapour and liquid phases can lead to phase stratification in the pipeline during its decompression. The fluid phase stratification creates phase slip and thermal nonequilibrium between the phases, significantly impacting the outflow rate. In this work, a two-fluid compressible flow model is used to investigate the impact of thermal non-equilibrium on transient CO2 pipeline decompression; the model predictions are compared with the results of simulations using HEM model as well as the experimental data on CO2 releases from a large-scale pipeline.

The Simulation Strategy and Its Realization in the Development Process of Active Safety and Advanced Driver Assistance Systems

Scipedia content — Thu, 28 Jan 2021 20:52:15 +0100

Design of a lane departure driver-assist system under safety specifications

Scipedia content — Thu, 28 Jan 2021 20:48:47 +0100

We use a controlled invariance approach to design a semi-autonomous lane departure assist system that is guaranteed to keep the vehicle in the lane. The controlled invariant safe set is the set of system states from which an input exists that can keep the vehicle in the lane. First we provide theoretical conditions under which this set has a simple characterization and can be computed in real-time. We then use this characterization to derive a feedback strategy that keeps the vehicle in the lane and overrides the driver only if he/she could otherwise force a future lane departure.

Robust Hinf desing of an antomotive cruise control system

Scipedia content — Thu, 28 Jan 2021 20:21:40 +0100

International audience; Advanced Driver Assistance Systems (ADAS) are in the focus of the vehicle control research. In the paper, the design method of a controller for a longitudinal ADAS system of a test vehicle is proposed. The cruise control must guarantee precise velocity tracking at varying vehicle mass and road inclinations. The mass variation and road slope changes are formulated as disturbances of the system. A combined robust Hinf and feedforward control design method is applied, which guarantees the robustness of the system against disturbances and considers actuator dynamics. The resulting control algorithm is implemented in CarSim. Simulation scenarios on the Mulhouse-Belfort highway section are performed to illustrate the efficiency of the method.

Reliability over time of EEG-based mental workload evaluation during Air Traffic Management (ATM) tasks

Scipedia content — Thu, 28 Jan 2021 20:17:33 +0100

International audience; Machine-learning approaches for mental workload (MW) estimation by using the user brain activity went through a rapid expansion in the last decades. In fact, these techniques allow now to measure the MW with a high time resolution (e.g. few seconds). Despite such advancements, one of the outstanding problems of these techniques regards their ability to maintain a high reliability over time (e.g. high accuracy of classification even across consecutive days) without performing any recalibration procedure. Such characteristic will be highly desirable in real world applications, in which human operators could use such approach without undergo a daily training of the device. In this work, we reported that if a simple classifier is calibrated by using a low number of brain spectral features, between those ones strictly related to the MW (i.e. Frontal and Occipital Theta and Parietal Alpha rhythms), those features will make the classifier performance stable over time. In other words, the discrimination accuracy achieved by the classifier will not degrade significantly across different days (i.e. until one week). The methodology has been tested on twelve Air Traffic Controls (ATCOs) trainees while performing different Air Traffic Management (ATM) scenarios under three different difficulty levels.

Learning user preferences in matching for ridesharing

Scipedia content — Thu, 28 Jan 2021 20:15:34 +0100

Sharing car journeys can be very beneficial, since it can save travel costs, as well as reducing traffic congestion and pollution. The process of matching riders and drivers automatically at short notice, is referred to as dynamic ridesharing, which has attracted a lot of attention in recent years. In this paper, amongst the wide range of challenges in dynamic ridesharing, we consider the problem of ride-matching. While existing studies mainly consider fixed assignments of participants in the matching process, our main contribution is focused on the learning of the user preferences regarding the desirability of a choice of matching; this could then form an important component of a system that can generate robust matchings that maintain high user satisfaction, thus encouraging repeat usage of the system. An SVM inspired method is exploited which is able to learn a scoring function from a set of preferences; this function measures the predicted satisfaction degree of the user regarding specific matches. To the best of our knowledge, we are the first to present a model that is able to implicitly learn individual preferences of participants. Our experimental results, which are conducted on a real ridesharing data set, show the effectiveness of our approach.

The Setting Method of Signal Timing Parameters at Over-saturated Intersection

Scipedia content — Thu, 28 Jan 2021 20:12:31 +0100

In order to adapt to traffic operation situation of over-saturated signalized intersection, the setting methods of optimal cycle and green split of every phase are studied. Selecting Xinan Rd. and Wuyi Rd. intersection as study object, traffic investigation was carried out. Considering the two factors of the average delay and capacity at over- saturated intersection comprehensively, the optimization method of signal cycle length was proposed. Considering the traffic volume and queue length, setting method of the green splits of every phase was also proposed. Using the measured traffic data, signal timing scheme of the investigated intersection was not only designed, but also compared with the existing situation. The research indicates that, using this method, the average delay will be increased at over- saturated intersection, and the capacity can also be increased. This method is beneficial to reduce vehicles queuing at this kind of intersection.

Optimal design of switched Ethernet networks implementing the Multiple Spanning Tree Protocol

Scipedia content — Thu, 28 Jan 2021 20:04:04 +0100

International audience; Switched Ethernet networks rely on the Spanning Tree Protocol (STP) to ensure a cycle-free connectivity between nodes, by reducing the topology of the network to a spanning tree. The Multiple Spanning Tree Protocol (MSTP) allows for the providers to partition the traffic in the network and assign it to different virtual local area networks, each satisfying the STP. In this manner, it is possible to make a more efficient use of the physical resources in the network. In this paper we consider the traffic engineering problem of finding optimal designs of switched Ethernet networks implementing the MSTP, such that the worst-case link utilization is minimized. We show that this problem is N P-hard. We propose three mixed-integer linear programming formulations for this problem. Through a large set of computational experiments, we compare the performance of these formulations. Until now, the problem was almost exclusively solved with heuristics. Our objective here is provide a first comparison of different models that can be used in exact methods.

Agent-Based Modelling and Simulation of Trajectory Based Operations under Very High Traffic Demand

Scipedia content — Thu, 28 Jan 2021 20:03:50 +0100

Analysis of the Effects of Intermodal Terminals for the Solutions of Urban Logistics Problems in Istanbul City

Scipedia content — Thu, 28 Jan 2021 20:02:03 +0100

We analyzed the urban logistics problems in Istanbul City, and we tried to show the solutions of these problems thanks to intermodal freight terminals. Istanbul is a center of trade, tourism, and industry; 60 % of total logistics activities take place in Istanbul. At the same time, capacities, infrastructures, and performance of logistics system are affecting the logistics systems and industries of European countries and neighborhoods. However, solving the urban logistics problems have become regional and global ones and especially European countries, industries, and their commercial actors cannot ignore these problems. In addition to urban freight flows, high volume of international and domestic cargo flows causes different problems related to urban logistics. On the other hand, Istanbul has the different logistics nodes as airports, organized industrial zones, business centers, whereas logistics networks and links between nodes are not required level. This study focuses on the logistics nodes, relationships, opportunities and facilities of transportation, and effects of intermodal freight terminals to solving problems of the insufficient connections between these nodes.

An Integrated Numerical Approach to Design Offshore Pipelines Susceptible to Lateral Buckling

Scipedia content — Thu, 28 Jan 2021 20:00:42 +0100

Lateral buckling is a global response to excessive compressive axial force due to thermal and internal pressure loads which when combined, exceeds the initiating Euler Buckling force and overcomes the lateral friction force reacting against a pipeline laid on the seabed."/jats:p" "jats:p"According to DNV-RP-F110, the integrity of a pipeline susceptible to buckling can be assured by either restraining the pipeline, thus sustaining large axial compressive forces, or releasing them through a combination of pipeline displacements; lateral buckles. Buckling may be rogue in nature or engineered at predetermined locations, either of which must demonstrate compliance to DNV OS F101. Engineered lateral buckles are a cost effective way to manage for example HP/HT pipelines as opposed to the construction of restraint designs. However, uncertainty in the initial buckle formation process and buckle behaviour may reduce design reliability; resulting in an increased level of redundancy in a buckle management system."/jats:p" "jats:p"This paper presents the vision of an engineering tool aimed at providing an integrated single model environment which enables straightforward engineering analysis, with application to all phases of design, and providing support to operations. Verification of buckling forces and post-buckling configurations is undertaken through comparison with Hobbs and Kerr analytical models and validated against ABAQUS.

Numerical modelling of the slurry flow in pipelines and prediction of flow regimes

Scipedia content — Thu, 28 Jan 2021 19:58:16 +0100

Large scale numerical modelling of slurry flow in horizontal pipelines has been carried out. A combination of analytical and commercial CFD modelling, with Eulerian two-phase flow models, has been used in the present investigation. The modelling results are validated with well-documented experimental data and are found to be in good agreement. Flow regime maps were developed and pressure drops calculated for a wide range of flow rates, particle sizes and solid concentrations. It was observed that flow regime maps calculated with analytical empirical correlations near the transition flow regimes are unreliable. It is concluded that the performance of this model at the presented scales allows for application at smaller scales that still feature turbulent flows.

Driving space detection by combining V-disparity and C-velocity

Scipedia content — Thu, 28 Jan 2021 19:56:04 +0100

International audience; This paper deals with road plane detection by image analysis in the context of automatic driver assistance systems. In this context, free navigable space detection is a very important step for any navigation and obstacle detection system. We propose a low-level combination of two main visual processes: stereovision and motion. We define a common representation that allows simple projections of stereo information to easy-interpretable features in a motion space. We chose to combine two robust cumulative techniques: the stereo-based approach V-disparity and the motion-based approach C-velocity. The combination requires the definition of a common formalism. Results on synthetic image sequences and on KITTI database images reveal that our approach is more efficient than a higher level combination method. We show that it is possible, using no prior knowledge nor any calibration, to improve detection by a low cost method that exploits only image processing and a very simple stereo and motion combination.

TSP model for electric vehicle deliveries, considering speed, loading and path slope.

Scipedia content — Thu, 28 Jan 2021 19:53:33 +0100

In the current Transport White Paper, the European Union presents a roadmap for a more competitive and sustainable European transport system. Concerning Urban Freight Transport, responsible for about a quarter of CO2 emissions of the transport sector, one of the goals of the EU is to achieve essentially CO2-free city logistics in major urban centres by 2030 by developing and deploying new and sustainable fuels and propulsion systems. The gradual phasing out of ‘conventionally-fuelled’ vehicles from the urban environment contributes to reduce oil dependence, greenhouse gas emissions and local air and noise pollution. To meet European air quality standards, authorities of some major European cities have already introduced Low Emissions Zones where access to urban areas is limited to freight vehicles that meet certain emissions standards. Greater use of low-emission urban trucks based on electric, hydrogen and hybrid technologies would reduce air emissions, but also noise, letting to use road infrastructure more efficiently by making night deliveries and avoiding morning and afternoon peak periods. In addition to their role in the reduction of polluting emissions, the development of low-emission vehicles also allows to mitigate the dependence of the transportation sector to high fossil fuel prices. Electric vehicles have the potential to be powered by renewable energy sources such as wind and solar energy. However, weaknesses can be found in the limited capacity of the battery and the time needed to recharge, and consequently, the limited driving range of electric vehicle. The main sources for final energy consumption are the vehicle size and the engine characteristics, the load factor, the driving pattern, the gradient which represent the average topology of the country, the speed and the acceleration. To maximize the driving range, a routing model, which aims at minimizing the energy consumption, has to be developed. Our paper focus on the Electric Vehicle Traveling Salesman Problem (EV-TSP): given n cities, find the shortest tour, i.e., the shortest directed cycle containing all cities. The classical objective is to minimize the cost tour scheduling to fulfill delivery requests at each location. In this paper we consider the energy cost and we present an extension of the classical problem to minimize the remaining storage capacity of all electric vehicles at the destination node, knowing that there is no recharge operation on the tour. The objective function accounts not just for the travel distance but also on the load of the vehicle and on its speed while the energy consumption of the engine additionally depends on the path to travel, on the slope of the roads and on the vehicle specifications. Moreover, negative consumption that may happen due to regenerative breaking and kinetic energy capture on downhill paths is taken into consideration. Mathematical model is described and computational experiments are performed. Peer reviewed

Development of an ATC Tower Simulator to Simulate Ground Operations

Scipedia content — Thu, 28 Jan 2021 19:45:45 +0100

International audience; The expected growth in air traffic has resulted in many projects attempting to mitigate the problem of air traffic control, particularly at airports. These projects have focused on characterizing the workload of the air traffic control officer and/or introducing automated technology to assist in his or her responsibilities. Many of these projects have used existing simulation facilities and technology or developed analogous environments to simulate the air traffic control tower. However, such high-fidelity simulation facilities are in limited loca- tions or not easily accessible. Results gathered in simplified environments, while accurate in a controlled setting, may be limited in their extrapolation to real-world applications. Furthermore, little guidance is provided in the literature for developing an ATC tower micro-world, particularly in terms of knowing which elements are most necessary to simu- late and the most effective way to actualize such functions. In this paper, we present the development of an air traffic control tower simulator, specifically for the ground controller, intended for the design and validation of potential automated concepts. We discuss our reasoning for the simulation of specific elements, the hardware and the software used, and our methodology for simulating ATC operations within the tower. This paper concludes with lessons learned and results from the simulation validation, a novel 10-question 5-point Likert scale questionnaire.

Enhancing decision-making by leveraging human intervention in large-scale sensor networks

Scipedia content — Thu, 28 Jan 2021 19:41:31 +0100

Extensive deployment of sensor networks in recent years has led to the generation of large volumes of data. One approach to processing such large volumes of data is to rely on parallelized approaches based on architectures such as MapReduce. However, fully-automated processing without human intervention is error prone. Supporting human involvement in processing pipelines of data in a variety of contexts such as warfare, cyber security, threat monitoring, and malware analysis leads to improved decision-making. Although this kind of human-machine collaboration seems straightforward, involving a human operator into an automated processing pipeline presents some challenges. For example, due to the asynchronous nature of the human intervention, care must be taken to ensure that once a user-made correction or assertion is introduced, all necessary adjustment and reprocessing is performed. In addition, to make the best use of limited resources and processing capabilities, reprocessing of data in light of such corrections must be minimized. This paper introduces an innovative approach for human-machine integration in decisionmaking for large-scale sensor networks that rely on the popular Hadoop MapReduce framework.

Performance Enhancements for the Detection of Rectangular Traffic Signs

Scipedia content — Thu, 28 Jan 2021 19:37:15 +0100

Most countries around the world present regulation and rules, applying on public roads, by putting up traffic signs. Therefore it is useful for driver assistance systems and important for autonomous vehicles to understand the meaning and consequences of those signs. One class of traffic signs that present important information is speed limit signs, which underlie strict norms. In this paper, we will introduce performance enhancing methods for the detection of rectangular traffic signs on the example of speed limit signs in the United States of America (USA). We will show that with a small and acceptable loss of accuracy the number of calculations needed and their complexity can be greatly reduced. Due to that, the energy consumption of the embedded hardware and the processing time per frame are reduced.

Dynamic Virtual Network Traffic Engineering with Energy Efficiency in Multi-location Data Center Networks

Scipedia content — Thu, 28 Jan 2021 19:30:15 +0100

For cloud enterprise customers that require services on demand, data centers must allocate and partition data center resources in a dynamic fashion. We consider the problem in which a request from an enterprise customer is mapped to a virtual network (VN) that is allocated requiring both bandwidth and compute resources by connecting it from an entry point of a data center to one or more servers, should this data center be selected from multiple geographically distributed data centers. We present a dynamic traffic engineering framework, for which we develop an optimization model based on a mixed-integer linear programming (MILP) formulation that a data center operator can use at each review point to optimally assign VN customers. Through a series of studies, we then present results on how different VN customers are treated in terms of request acceptance when each VN class has a different resource requirement. We found that a VN class with a low resource requirement has a low blocking even in heavy traffic, while the VN class with a high resource requirement faces a high service denial. On the other hand, cost for the VN with the highest resource requirement is not always the highest in the heavy traffic because of the significantly high service denial faced by this VN class.

Decentralized model predictive control for smooth coordination of automated vehicles at intersection

Scipedia content — Thu, 28 Jan 2021 19:26:46 +0100

International audience; We consider the problem of coordinating a set of automated vehicles at an intersection with no traffic light. The priority-based coordination framework is adopted to separate the problem into a priority assignment problem and a vehicle control problem under fixed priorities. This framework ensures good properties like safety (collision-free trajectories, brake-safe control) and liveness (no gridlock). We propose a decentralized Model Predictive Control (MPC) approach where vehicles solve local optimization problems in parallel, ensuring them to cross the intersection smoothly. The proposed decentralized MPC scheme considers the requirements of efficiency, comfort and fuel economy and ensures the smooth behaviors of vehicles. Moreover, it maintains the system-wide safety property of the priority-based framework. Simulations are performed to illustrate the benefits of our approach.

Document type: Conference object

Design and development of devices based on digital slurry pipeline management system

Scipedia content — Thu, 28 Jan 2021 19:21:51 +0100

In recent years, development of mineral pipeline is rapid, which is one of the best way to solve the question fine iron ore output in the complex terrain of the western china. Application practice shows that the method of mineral pipeline transportation solved a series of defect from other transportation mode including waste resource etc. Equipment management and maintenance are foundation work of pipeline transportation. They act pivotal role in the production of iron ore slurry pipeline length, only strengthen the management and maintenance of equipment management system to maximize the performance of equipment, to ensure the pipeline business production operate normally. Equipment maintenance management is an important component of the equipment management system. Improvements of equipment maintenance management will play an important role in consummating equipment management system.

Empirical study of traffic velocity distribution and its effect on VANETs connectivity

Scipedia content — Thu, 28 Jan 2021 19:21:38 +0100

In this article we use real traffic data to confirm that vehicle velocities follow Gaussian distribution in steady state traffic regimes (free-flow, and congestion). We also show that in the transition between free-flow and congestion, the velocity distribution is better modeled by generalized extreme value distribution (GEV). We study the effect of the different models on estimating the probability distribution of connectivity duration between vehicles in vehicular ad-hoc networks.

Comment: 5 pages, 5 figures, presented at the ICCVE 2014 (International conference on connected vehicles & expo); http://www.iccve.org

Research on the strategy of group vehicle intelligent perception and traffic route guidance of semantic car road network

Scipedia content — Thu, 28 Jan 2021 19:17:50 +0100

Vehicle road network has become the development direction of the future transport system. In this paper, semantic modeling of car road network is built, semantic integration and sharing problems of heterogeneous networking information is solved. The Group car intelligent perception and effective cognitive method is explored. The dynamic traffic flow guidance strategies is proposed, to realize intelligent processing of massive car road network information. Keywords-car road network; traffic route guidance; intelligent transportation system

Online Traffic Congestion Prediction Based on Random Forest

Scipedia content — Thu, 28 Jan 2021 19:07:41 +0100

In recent years, distinction and prediction of urban traffic congestion has become an important part of Intelligent Transportation System (ITS), hence attracting more and more attentions. Road congestion can be predicted by analyzing traffic flow data collected by various data acquisition equipment primarily. However, existing methods not only need to store large amount of historical information, but has not enough suitability for large-scaled and changing traffic flows. Therefore, an online prediction method based on Random Forest (RF) is put forward in this paper and the prediction on congestions is made by real-time data instead of digging the historical data. Simulation and experiment results show that the design presented in this paper improves accuracy of predictions and it has a certain use value.

Introducing database communication technologies for TED replication in multi-domain networks

Scipedia content — Thu, 28 Jan 2021 19:04:01 +0100

In multi-domain transport networks, exchange of Traffic Engineering information is required to enable effective end-to-end service provisioning and restoration by efficiently utilizing network resources. So far, several solutions have been proposed by the communication community such as the Hierarchical Path Computation Element (H-PCE) architecture. Using the H-PCE architecture a parent PCE is responsible for inter-domain path computation, while a dedicated child PCE performs intra-domain path computation within each domain. However, this approach can introduce scalability concerns especially under dynamic traffic condition such as during restoration because all path computation procedures are coordinated by the parent PCE and may require the exchange of many control messages. This paper proposes a standard communication among database systems located at the child PCEs, to exchange and share YANG-based Traffic Engineering information in multi-domain networks. By exploiting currently available database technologies, scalable and predictable performance is demonstrated for both replication mechanisms among child PCEs and information retrieval from the stored databases. Thus, this proposal enables the sharing of intra-domain information at each cPCE that can be locally used, upon failure, to speed-up the recovery procedure.

Wide-scoped Surrounding Top-view Monitor for Advanced Driver Assistance Systems

Scipedia content — Thu, 28 Jan 2021 18:59:59 +0100

To improve the scope range of the traditional around view monitor (AVM) systems for Advanced Driver Assistance Systems (ADAS), we propose a wide-scoped surrounding top-view monitor (STM) system with the same equipment as the traditional AVM system. In the proposed system, four wide-view cameras are mounted on front, rear, and the both sides of the vehicle to capture sequential images; then each four images are composed into a single seamless surrounding top-view image of the vehicle with the view radius more than 30 meters. The proposed system consists of eight stages: camera calibration, vignetting effect elimination, distortion calibration, top-view transformation, image registration, brightness uniformity, color blending, and bowl model mapping. The system performance and image quality are evaluated in experiment.

Analysis on the Connotation of Green Logistics

Scipedia content — Thu, 28 Jan 2021 18:58:47 +0100

Green logistics which based on ecological environmental protection and sustainable development changed the unilaterally influencing relations between development and logistics, life of consumption and logistics, and it represented the future development direction and trend of logistics. Based on existing definitions of green logistics, this paper analyzed the connotation and related concepts of green logistics both in China and abroad and dissected the connotation of green logistics in aspects of objective, function, content, actors, etc. And the insufficiency of existing research results and future development direction were given on the basis of existing research results. In the current society, with the rapid development of economy, modern logistics activity has become increasingly frequent. At the same time, development of these two just affects each other. It is undeniable that development of modern logistics will promote economic development; meanwhile, rapid development of economy can also increase the logistics quantity. Therefore, they just supplement each other. With continuous development of economy, the demand for logistics increases continuously. Under the condition of high demand, many problems occur, such as urban traffic congestion, waste of resources and fuel consumption. Under such situations, the influence of logistics development on social environment is quite severe and it goes against sustainable development of economy in a new period. At present, people's environmental awareness increases gradually, and they begin to explore new logistics systems which can not only satisfy the demand of social development but also restrain the influence of logistics activity on environment. Thereby, "green logistics" emerges as the times require. "Green logistics" not only effectively improves the environment pollution problems of traditional logistics but also accords with the general trend of the current environmental protection. Therefore, it is the direction of future logistics development. As for study on "green logistics", a definition is proposed for green logistics in Logistics Terms (GB/T 18354-2001) published in 2001. However, the extensive logistics professionals lack a comprehensive understanding about green logistics and its characteristics. As a result, they cannot fully understand and even misunderstand green logistics, or some unnecessary faults might be caused. Therefore, it can provide reference for practical work of green logistics to strengthen cognition about green logistics and accurately comprehend the connotation of green logistics.

Research on Traffic Accident Forecasting Based on Gray Model

Scipedia content — Thu, 28 Jan 2021 18:47:09 +0100

the road traffic system is an uncertain system, the occurrence of traffic accidents is also an uncertain system with partial information known and the other unknown. Therefore, it’s suitable to apply the gray model theory to predict the traffic accidents. This paper expounds the principles of gray model and gives an example to show the feasibility and practicability of the gray model applied in the forecasting of traffic accidents. Gray Feature of Traffic Accidents Traffic accidents often result in serious consequences, such as casualties, vehicle damage, road congestion and other serious consequences. It’s necessary to explore the development trend of road traffic accidents and the development trend of future traffic accidents to prevent and reduce the occurrence of accidents and the loss of traffic accidents. Traffic accident prediction is based on the statistics, analysis and treatment of accident data, and based on the accident causes and development law. Through scientific analysis, we can see that it is not clear that the accident in advance to make logical reasoning. Traffic accident prediction is a key problem in road traffic safety planning, decision making and traffic engineering project benefit evaluation. It has important practical significance to predict the correct or not directly related to the construction of traffic facilities, the formulation of traffic management policies and the allocation of investment funds. Correctly analyzing the characteristics of road traffic accidents and establishing a high quality forecasting model is the key to predict the traffic accidents. Probability statistics, fuzzy mathematics and gray system theory are the three most commonly used uncertainty systems. Probability statistics mainly uses the regression forecasting model to forecast road traffic accident. The shortcoming of the regression forecasting model is that the establishment of the model needs a lot of traffic accident history data, leaving a large amount of data support, the determination of the equation parameters is very difficult to have the power of persuasion. And the gray prediction method can overcome the above shortcomings, it does not require a large amount of data support, and do not need data to obey the typical probability distribution, even in the case of only a few data can be established to predict the model. The occurrence of road traffic accidents is not obvious. It is a random change. It has the characteristics of random and fuzzy. The occurrence time of traffic accident, the occurrence, the law of the occurrence, the damage is not expected. For random variable, random process, people often use the method of probability statistics. And the method of probability statistics requires that data is large, it must be found out from a large amount of data, and can solve the problem. The gray system theory, then, is considered to be a gray quantity of the change in a certain range, and the random process can be seen as a gray process that changes in a certain range. The gray amount is not from the perspective of statistical rules, through large sample size, but with the data processing method, the chaos of the original data into a more regular pattern of production and then do research. If we consider road traffic in a region as a certain system, the system is gray with some certain factors (white information), such as road conditions, signal signs, etc., and some uncertain factors (black information), such as vehicle condition, climate, driver's psychological state, etc. It can be considered as a gray system which can be used to deal with gray system theory. 4th International Conference on Computer, Mechatronics, Control and Electronic Engineering (ICCMCEE 2015) © 2015. The authors Published by Atlantis Press 71 Establishment of Gray Model Overview of the Method Firstly, we suppose the road traffic accident data sequence is (0) (0) (0) (0) 1 2 { , , , } n x x x x = 2 . We use the gray system theory to establish the GM (1, 1): (1) (1) ( 1) [ (1) ] t b b x t x e μ μ μ − + = − + . The expression is the predicted values of the generated sequence. However, what we need is the predictive value of the original sequence. Therefore, it’s necessary of accumulated generating operation to achieve the predictive value of the original sequence: (0) (1) (1) (1) (1) (1) (1) 1 2 { , , , } n x a x a x a x = 2 . In the above expression, (1) (1) (1) (1) (0) 1 1 t t t a x x x x − = − = . Accuracy Test The test of residual error, that is ( ) E t : (0) (0) ( ) ( ). ( ) E t x t x t ∆ = . The relative residual error is: (0) ( ) ( ) ( ) E t e t x t = . The test of posteriori error: Suppose the mean of the original sequence and the residual errors respectively are x , E . Suppose the mean square error of the original sequence and the residual errors respectively are 2 1 S , 2 2 S . Therefore, the ratio of posteriori error i

Performance Impact of Improved Departure Time Prediction Relative to Sector Demand & Arrival Time Predictability

Scipedia content — Thu, 28 Jan 2021 18:42:33 +0100

This thesis deals with traffic forecasts of Airspace Users for Air Navigation Service Providers. Currently there is a high amount of uncertainty in the traffic forecast. Air Traffic Flow Managers anticipate for unforeseen traffic by increasing the forecasted maximum capacity threshold by more than 10%. The European ATM research program SESAR aims ultimately to reduce the difference between the forecast and real maximum capacity threshold by less than 3%. Prediction uncertainty results in sector over-load and sub-optimal traffic flow in the air transportation system. The objective of this thesis is to investigate sector demand predictability by quantification of the difference between real and forecast traffic, and evaluate the predictability improvement by improvement of departure time predictions. Statistical analysis is performed by plotting time & count uncertainty against look-ahead time to sector entry. On a busy day, for a look-ahead time of 2 hours and longer, flights have a higher probability to be delayed than to be earlier as planned. A comparison is made between the forecast and real number of flights entering a sector for a given time of day window. Looking at the forecast time period, it can be seen that some forecasted flights did not enter in the window anymore (out), and some additional flights entered in the window that were initially not forecasted (in). `In' and `out' flights can be explained due to flights being earlier or delayed, or flights deviating from the planned route. Looking at 10 minutes before entry, about 30% to 40% are in/out flights, which is a large amount. In general, for a look-ahead of 0 to 3 hours, there are more `out' than `in' flights resulting in an over-prediction. Over-prediction means that there are more flights anticipated than really entered for a given time window. In order to reduce over-prediction, it is suggested, taking safety into account, to reduce the number of `out' flights that deviate from the planned route. For a high capacity Maastricht Upper Area Control sector on a normal day, a 5% decrease of these `out' flights, reduces the over-prediction by 10%. Furthermore, flight phases that are major causes of uncertainty are descent, taxi and the slot allocation process. A departure time prediction improvement of 50% results in 20% arrival time error reduction, and 30% mean sector entry time error reduction, for a 6 hour look-ahead time. The used sensitivity method does not yield realistic sector occupancy count because the effect of changed ATC procedures due to improved predictability is not incorporated.

An approach for the evaluation and implementation of mixed rail operations in harmony with non-motorized trails and urban structure: the case of Xalapa, Mexico

Scipedia content — Thu, 28 Jan 2021 18:40:57 +0100

n integrated transportation system is a prerequisite for urban sustainability. Inefficient transportation systems contribute to pollution, increase transportation time and costs, and promote urban sprawl. Midsize Mexican cities are increasingly vulnerable to these problems due to planning that focuses on individual mobility and separation of land uses. Part of the solution presented in this paper through the case of the city of Xalapa, Mexico is to use existing underutilized urban railroad corridors for the implementation of light and freight rail mixed operations with non-motorized trails. The solution promotes multimodal mobility, accessibility, and connectivity while making use of resources efficiently through multifunctional spaces and infill development. These in turn increase train operation safety and capacity, reduce urban barriers, promote harmonious city-train coexistence and urban compactness. Mixed rail operation with trails is complex and their technical, technological, operational, and institutional aspects need to be established and adapted from existing models. This paper is the first step toward establishing the requirements for implementation in the context of midsize Mexican cities. The findings would be the basis for the development of a standardized evaluation framework to determine the system’s feasibility. The framework is based on a German evaluation scheme used for the evaluation of large public transportation investments.

Research on Passenger Seat Choice Behavior in Airline Revenue Management

Scipedia content — Thu, 28 Jan 2021 18:15:10 +0100

ong with the gradually growing fierce competitions in air transport market, all large airline companies are seeking ways to increase revenues and enhance competitiveness, setting basis for application of revenue management system in domestic market. Taking revenue management theory as the background and combined with existing research results of passenger choice behavior theory, in the thesis, exploratory researches on airline passenger seat choice are made. Analysis on passenger seat choice behavior from the aspect of consumer behavior theory, and choice preference and choice probability of passengers under the circumstance of different seat classes in the same flight are researched. This thesis includes the following aspects: firstly, reviewing history of revenue management development, pointing out the main direction of the research, summarizing theory, research history and current status of discrete choice model and PODS passenger choice model in de tails and analyzing similarities and differences between applications the two models. Secondly, a pplying discrete choice model and analytic hierarchy process to establish passenger seat choice model and estimating parameters of the established model, then further analyzing application of this model in seat inventory control. Thirdly, discussing application status of the passenger choice model through investigation, and comparing with the actual survey results to prove practicability and validity of the established model.

Doppler and pathloss characterization for vehicle-to-vehicle communications at 5.8 GHz

Scipedia content — Thu, 28 Jan 2021 18:09:31 +0100

Due to significant increase in vehicular accident and traffic congestions, vehicle to vehicle (V2V) communication based on the intelligent transport system (ITS) was introduced aiming to significantly reduce vehicular accident and traffic congestion. However, to carry out efficient design and implementation of a reliable vehicular communication systems, a deep knowledge of the propagation channel characteristics in different environments is crucial, in particular the Doppler and pathloss parameters. This paper presents an empirical V2V channel characterization and measurement performed under realistic urban, suburban and highway driving conditions in Brisbane, Australia. Based on Lin Cheng statistical Doppler Model (LCDM), values for the RMS Doppler spread and coherence time due to time selective nature of V2V channels are presented. Also, based on log-distance power law model, values for the mean pathloss exponent and the standard deviation of shadowing were reported for urban, suburban and highway environments. The V2V channel parameters can be useful to system designers for the purpose of evaluating, simulating and developing new protocols and systems.

Unmanned Aircraft Systems for Geotechnical Monitoring of Pipelines in the Arctic

Scipedia content — Thu, 28 Jan 2021 18:08:58 +0100

Prediction of traffic flow based on the EMD and wavelet neural network

Scipedia content — Thu, 28 Jan 2021 17:56:29 +0100

. The operation of the urban traffic exist a high degree of complexity and randomness. The key of Intelligent Transportation System is the real-time and accurate traffic flow prediction. Taking effective measures in a timely manner would prevent the occurrence of traffic accidents since traffic congestion brings much traffic inconvenience to people. Real-time traffic flow prediction plays a significant role in easing traffic congestion and guiding convenient travelling. Therefore, considering the characteristics of traffic flow, this paper presents a neural network, wavelet analysis method, and the EMD and wavelet neural network method respectively. Three methods are utilized in simulating the same set of traffic data and then the most effective way of solving traffic congestion is obtained by taking contrast analysis of simulation result.

Path Clustering Based on a Novel Dissimilarity Function for Ride-Sharing Recommenders

Scipedia content — Thu, 28 Jan 2021 17:54:06 +0100

Ride-sharing practice represents one of the possible answers to the traffic congestion problem in today's cities. In this scenario, recommenders aim to determine similarity among different paths with the aim of suggesting possible ride shares. In this paper, we propose a novel dissimilarity function between pairs of paths based on the construction of a shared path, which visits all points of the two paths by respecting the order of sequences within each of them. The shared path is computed as the shortest path on a directed acyclic graph with precedence constraints between the points of interest defined in the single paths. The dissimilarity function evaluates how much a user has to extend his/her path for covering the overall shared path. After computing the dissimilarity between any pair of paths, we execute a fuzzy relational clustering algorithm for determining groups of similar paths. Within these groups, the recommenders will choose users who can be invited to share rides. We show and discuss the results obtained by our approach on 45 paths.