Scipedia: Documents published in 2011

Fatigue Failure of Large-Diameter Cast Iron Mains

Scipedia content — Thu, 28 Jan 2021 20:13:06 +0100

Water utility engineers have reported on large diameter water main failures that occurred suddenly without warning, no signs of prior leaks and no visual evidence of corrosion on the fracture surfaces. Often these failed mains had been operating without major problems for over 80 years. A possible explanation may be attributed to alternating or fluctuating stresses such as those caused by heavy traffic and cyclical operating water pressure with occasional occurrences of transients. These fluctuating stresses are accentuated if the pipe impinges on an object with sharp geometry and high stiffness like a rock or a stone. Fatigue of cast iron has been extensively studied in the context of cast iron bridges, structural elements such as columns, engine blocks, etc, but not in the context of buried, grey cast iron water pipes. Fatigue analysis methods developed over the years involve a lot of empiricism and combine engineering principles with experimental observations. Consequently, it is fair to say that fatigue analysis results should be taken more as a guide than as precise or accurate answers. A mechanistic approach to explain fatigue failures of buried cast iron pipes had not been previously explored. This paper explores the application of the fracture mechanics approach (LEFM) to explain some failures in cast iron pipes that occur through the fatigue mechanism. It endeavors to provide insight into the plausibility of fatigue failures in grey cast iron pipes when and if subjected to alternating (also often referred to as repeated or variable) stresses due to surface traffic loads, operating pressure variations and transient pressure occurrences. It is important to note that the proposed analysis refers to grey cast iron pipe type, with carbon in form of flake graphite, which is the predominant material of existing iron trunk mains in North America and Europe.

Behavior classification algorithms at intersections and validation using naturalistic data

Scipedia content — Thu, 28 Jan 2021 19:56:18 +0100

The ability to classify driver behavior lays the foundation for more advanced driver assistance systems. Improving safety at intersections has also been identified as high priority due to the large number of intersection related fatalities. This paper focuses on developing algorithms for estimating driver behavior at road intersections. It introduces two classes of algorithms that can classify drivers as compliant or violating. They are based on 1) Support Vector Machines (SVM) and 2) Hidden Markov Models (HMM), two very popular machine learning approaches that have been used extensively for classification in multiple disciplines. The algorithms are successfully validated using naturalistic intersection data collected in Christiansburg, VA, through the US Department of Transportation Cooperative Intersection Collision Avoidance System for Violations (CICAS-V) initiative.

Oil-derivatives pipeline logistics using discrete-event simulation

Scipedia content — Thu, 28 Jan 2021 19:51:38 +0100

The management of oil-product pipelines represents a critical task in the daily operation of petroleum supply chains. Efficient computational tools are needed to perform this activity in a reliable and cost-effective manner. This work presents a novel discrete event simulation system developed on Arena® for the detailed scheduling of a multiproduct pipeline consisting of a sequence of pipes that connect a single input station to several receiving terminals. The pipeline is modeled as a non-traditional multi-server queuing system involving a number of servers at every pipe-end that perform their tasks in a synchronized manner. Based on priority rules, the model decides which server should dispatch the entity waiting for service to the associated depot. Each priority rule can lead to a different delivery schedule, which is evaluated by using several criteria. Combined with optimization tools, the proposed simulation technique permits to easily manage real-world pipelines operations with low computational effort.

Feedback control of the National Airspace System to mitigate weather disruptions

Scipedia content — Thu, 28 Jan 2021 19:51:24 +0100

This paper proposes a general modeling framework adapted to the feedback control of traffic flows in Eulerian models of the National Airspace System (NAS). It is shown that the problems of scheduling and routing aircraft flows in the NAS can be posed as the control of a network of queues with load-dependent service rates. We can then focus on developing techniques to ensure that the aircraft queues in each airspace sector, which are an indicator of the air traffic controller workloads, are kept small. This paper uses the proposed framework to develop control laws that help manage the NAS during a weather event, given a probabilistic forecast of capacities. We also address the management of airport arrivals and departures subject to runway capacity constraints, which are highly sensitive to weather disruptions.

Managing Risk and Operating in Environmentally Sensitive Areas: The Wetlands of the Northwest Louisiana Haynesville Shale

Scipedia content — Thu, 28 Jan 2021 19:42:48 +0100

The aerial extent of the Haynesville Shale play has been analyzed with regard to regulatory and permitting processes such that unavoidable surface impacts can be planned in a manner that allows operators to minimize both risk and cost from operations in environmentally sensitive areas – the wetlands of northwest Louisiana. A workflow has been developed and applied for operators with significant leaseholds seeking to understand the volume of wetlands that may be impacted due to construction of drilling pads, reserve pits, access roads, flowlines, pipelines and gathering systems that comprise field infrastructure. Working under new rules since 2008, regulatory agencies require offsets for unavoidable impacts to wetlands to occur in the watershed where the impacts are planned to occur. With limited mitigation acreage available in an area where surface rights are locked up by landowners and operators, the need for creative wetland analyses and mitigation solutions has risen to need-to-know-now status. Of the 4.3 million surface acres in the Louisiana and Texas Haynesville Shale play, more than 23% of the Louisiana play area is considered jurisdictional wetlands by the US Army Corps of Engineers. After operators avoid and minimize their wetlands impacts, GIS analysis of current and past land compositions and uses can be used to forecast future unavoidable wetland impacts from oil and gas development activities. Results of this analysis are used to formulate an appropriate compensatory mitigation solution that can be readily approved by regulatory agencies. Surface impact analysis employs a unique methodology and workflow that has shown to generate significant real-dollar savings for operators, allows compensatory mitigation plans to be proactively developed thereby accelerating agency regulatory processes, and transfers risk and liability from oil and gas operators to those delivering wetland mitigation solutions. Introduction and Statement of Theory An era of increased regulatory agency scrutiny for oil and gas operators developing U.S. onshore resource plays has served to heighten operator awareness of regulatory and permitting processes. Company executives, EHS” waters may be open, navigable waters like rivers, streams and lakes and also lands with certain hydrologic, soil and vegetative characteristics that have yielded a regulatory agency jurisdictional determination as “wetlands.” Guided by 1977 Executive Order 11990, the President George H. W. Bush administration implemented the policy that states that projects causing unavoidable impacts to wetlands are required to be offset by suitable mitigation of project impacts resulting in “no net loss” of wetlands. Surface impacts to wetlands are normally avoided by effective location of drilling pads and associated work surfaces outside jurisdictional wetland boundaries. When avoidance and minimization efforts result in operating areas containing wetlands,

How can the temperature affect the performance of a classical pipeline model when plastic pipes are used?

Scipedia content — Thu, 28 Jan 2021 19:29:10 +0100

In this paper, it is shown that the time-invariant nonlinear model normally used to design algorithms to isolate leaks in pipes can introduce errors when the pipe in question is a plastic one exposed to temperature changes. Thus, this model must have a mechanism to compensate temperature variations, if it is desired that such model follows in a more accurate way the dynamics of a liquid. A comparison of the behavior of the model with and without temperature compensation is made using real data coming from a plastic pipeline prototype transporting water.

Interference estimation in an aeronautical ad hoc network

Scipedia content — Thu, 28 Jan 2021 19:20:31 +0100

International audience; Recent research have considered aeronautical ad hoc networks as a possible mean for future aeronautical communications. By introducing inter- aircraft links, they are supposed to become an alternative to existing solutions based on direct air- ground or satellite links. In this paper, we propose the use of asynchronous Code Division Multiple Access (CDMA) in aeronautical ad hoc networks. We then present a simulation model developed with OPNET Modeler that estimates the impact of Multiple Access Interference (MAI) on packets delivery. Finally, we give the results of some simulations made with an ATC/AOC traffic model, and with real aircraft positions over the French sky.

A Web-Accessible Protein Structure Prediction Pipeline

Scipedia content — Thu, 28 Jan 2021 19:15:33 +0100

Proteins are the molecular basis of nearly all structural, catalytic, sensory, and regulatory functions in living organisms. The biological function of a protein is inextricably linked to its three-dimensional (3D) atomic structure. Traditional structure determination methods, such as X-ray and nuclear magnetic resonance techniques, are time-consuming, expensive, and infeasible for the millions of proteins that have been sequenced so far from various organisms. Alternatively, computational structure prediction methods provide a faster and more cost-effective, albeit approximate, alternative to experimental structure determination. We present a high-throughput protein structure prediction pipeline (dubbed “PSPP”), which given input protein sequences infers their 3D atomic structures. The pipeline was designed to be used with high performance computing clusters and to scale with the number of processors. The pipeline encompasses a core Perl module, a parallel job manager, and a Web browser graphical user interface accessible at our Website (www.bhsai.org). The software is currently installed at the Department of Defense (DoD) Maui High Performance Computing Center, and it is available for download along with its associated databases from our site. Currently, DoD scientists are using the pipeline in basic science and drug and vaccine development projects.

VTL zone-aware path cloaking algorithm

Scipedia content — Thu, 28 Jan 2021 19:13:48 +0100

Traffic engineering applications often benefit from collecting vehicle GPS traces in well-defined locations. As a motivating example, we will consider a traffic signal performance evaluation technique which requires GPS traces of vehicles traversing intersections. Since these applications do not require vehicle identity information, they are a good candidate for data de-identification techniques. Prior techniques can either provide data from specific locations or guarantee a high degree of anonymity under light traffic conditions but do not achieve both. In this paper, we propose a virtual trip line zone-aware path cloaking algorithm which combines these features. Zones where data should be retained can be predefined over the intersections of interest and the path cloaking algorithm uses entropy-estimates to decide whether the data can be revealed. Result obtained from a traffic simulator show that the application success rate increased from 39 to 82% compared to a zone-unaware path cloaking algorithm, while achieving a similar degree of privacy.

Challenges of NextGen Technologies for Coordinated Decision Making and the Exchange of Information between Pilots and Controllers

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

Introduction: This paper presents two studies that explore the implications of NextGen technologies for pilot/controller information exchange and coordinated decision making. Method: In Study 1 five participative focus groups were conducted with human factors experts. In Study 2 fifteen interviews were conducted with air traffic controllers. Both studies employed a thematic analysis. Results and Discussion: Results from Study 1 suggest that changes to pilot and controller information acquisition will alter rather than reduce breakdowns in coordinated decision making. Study 2 identified some basic issues in information exchange with NextGen technologies and suggests that some important non-operational information will be lost. Conclusion: The two studies highlight some important challenges that need to be carefully considered as the NextGen technologies move towards maturity. Language: en

Context aided fusion procedure for road safety application

Scipedia content — Thu, 28 Jan 2021 19:03:37 +0100

Proceeding of: 2012 IEEE Conference on Multisensor Fusion and Integration for Intelligent Systems (MFI), Hamburg, Germany, September 13-15, 2012. Road safety applications require the most reliable and trustable sensors. Context information plays also a key role, adding trustability and allowing the study of the interactions and the danger inherent to them. Vehicle dynamics, dimensions... can be very useful to avoid misdetections when performing vehicle detection and tracking (fusion levels 0 and 1). Traffic safety information is mandatory for fusion levels 2 and 3 by evaluating the interactions and the danger involved in any detection. All this information is context information that was used in this application to enhance the capacity of the sensors, providing a complete and multilevel fusion application. Present application use three sensors: laser scanner, computer vision and inertial system, the information given by these sensors is completed with context information, providing reliable vehicle detection and danger evaluation. Test results are provided to check the usability of the detection algorithm. This work was supported by the Spanish Government through the Cicyt projects FEDORA (GRANT TRA2010-20225-C03- 01), Driver Distraction Detector System (GRANT TRA2011-29454-C03-02). CAM through SEGVAUTO (S2009/DPI-1509). Publicado

Characterization of Tactical Departure Scheduling in the National Airspace System

Scipedia content — Thu, 28 Jan 2021 18:51:58 +0100

This paper discusses and analyzes current day utilization and performance of the tactical departure scheduling process in the National Airspace System (NAS) to understand the benefits in improving this process. The analysis used operational air traffic data from over 1,082,000 flights during the month of January, 2011. Specific metrics included the frequency of tactical departure scheduling, site specific variances in the technology’s utilization, departure time prediction compliance used in the tactical scheduling process and the performance with which the current system can predict the airborne slot that aircraft are being scheduled into from the airport surface. Operational data analysis described in this paper indicates significant room for improvement exists in the current system primarily in the area of reduced departure time prediction uncertainty. Results indicate that a significant number of tactically scheduled aircraft did not meet their scheduled departure slot due to departure time uncertainty. In addition to missed slots, the operational data analysis identified increased controller workload associated with tactical departures which were subject to traffic management manual re-scheduling or controller swaps. An analysis of achievable levels of departure time prediction accuracy as obtained by a new integrated surface and tactical scheduling tool is provided to assess the benefit it may provide as a solution to the identified shortfalls. A list of NAS facilities which are likely to receive the greatest benefit from the integrated surface and tactical scheduling technology are provided.

Limit, Shakedown and Ratchet Analyses of Defective Pipeline Under Internal Pressure and Cyclic Thermal Loading

Scipedia content — Thu, 28 Jan 2021 18:51:19 +0100

In this study, the limit load, shakedown and ratchet limit of a defective pipeline subjected to constant internal pressure and a cyclic thermal gradient are analyzed. Ratchet limit and maximum plastic strain range are solved by employing the new Linear Matching Method (LMM) for the direct evaluation of the ratchet limit. Shakedown and ratchet limit interaction diagrams of the defective pipeline identifying the regions of shakedown, reverse plasticity, ratcheting and plastic collapse mechanism are presented and parametric studies involving different types and dimensions of part-through slot in the defective pipeline are investigated. The maximum plastic strain range over the steady cycle with different cyclic loading combinations is evaluated for a low cycle fatigue assessment. The location of the initiation of a fatigue crack for the defective pipeline with different slot type is determined. The proposed linear matching method provides a general-purpose technique for the evaluation of these key design limits and the plastic strain range for the low cycle fatigue assessment. The results for the defective pipeline shown in the paper confirm the applicability of this procedure to complex 3-D structures.

Dynamic reconfiguration of terminal airspace during convective weather

Scipedia content — Thu, 28 Jan 2021 18:41:43 +0100

Dynamic airspace configuration (DAC) algorithms strive to restructure the U.S. National Airspace System (NAS) in ways that allow air traffic control to better manage aircraft flows. Although past research has largely focused on enroute airspace in clear weather conditions, the principle of better matching airspace structure to ambient conditions has potential to benefit airport terminal areas, which are often impacted by congestion due to convective weather, especially during summer months when travel demand is high. This paper studies the problem of dynamic airspace configuration in the terminal area given a stochastic model of route availability during convective weather conditions. An integer programming model is proposed for the dynamic reconfiguration of the terminal area. This model recommends small changes to airspace structure that alleviate airspace congestion, while limiting disruptions to air traffic control procedures. The model is tested against actual weather scenarios, and shows promising benefits to operations.

Technological Challenges for Alternative Fuels Technologies in the EU. A well-to-Tank Assessment and Scenarios Until 2030 Considering Technology Learning

Scipedia content — Thu, 28 Jan 2021 18:41:32 +0100

The initial step of this analysis corresponds to the evaluation of the current state of the art (SoA) for various alternative fuels (AFs) and alternative sustainable automotive technologies (ASATs) across Europe, taking into account their detailed energetic, environmental and economic variables. The method to assess economic and environmental performance of AFs and ASATs corresponds to a well-to-tank (WTT) and tank-towheel (TTW) assessment complemented by scenarios until 2030, with projections of reference and high prices of major input variables of analysis. This analysis determines short and long term economic performance taking into account technology learning. 2 generation biofuels offer potentials for meeting future fuel-energy demand, and are currently supported by main governments and programs. Initial results of this study also indicate that second generation biofuels offer promising solutions in terms of environmental performance but production costs, conversion efficiencies and by-products are major challenges that can influence the overall economic performance considerably. In addition, price volatilities for first generation biofuels feedstock play a major role on the competitiveness and economic performance of these fuels.

Thrust Restraint Concepts and Beam Loads for Segmented Pipelines at Bends

Scipedia content — Thu, 28 Jan 2021 18:34:51 +0100

Tracking vehicular speed variations by warping mobile phone signal strengths

Scipedia content — Thu, 28 Jan 2021 18:22:36 +0100

In this paper, we consider the problem of tracking fine-grained speeds variations of vehicles using signal strength traces from GSM enabled phones. Existing speed estimation techniques using mobile phone signals can provide longer-term speed averages but cannot track short-term speed variations. Understanding short-term speed variations, however, is important in a variety of traffic engineering applications—for example, it may help distinguish slow speeds due to traffic lights from traffic congestion when collecting real time traffic information. Using mobile phones in such applications is particularly attractive because it can be readily obtained from a large number of vehicles. Our approach is founded on the observation that the large-scale path loss and shadow fading components of signal strength readings (signal profile) obtained from the mobile phone on any given road segment appear similar over multiple trips along the same road segment except for distortions along the time axis due to speed variations. We therefore propose a speed tracking technique that uses a Derivative Dynamic Time Warping (DDTW) algorithm to realign a given signal profile with a known training profile from the same road. The speed tracking technique then translates the warping path (i.e., the degree of stretching and compressing needed for alignment) into an estimated speed trace. Using 6.4 hours of GSM signal strength traces collected from a vehicle, we show that our algorithm can estimate vehicular speed with a median error of ± 5mph compared to using a GPS and can capture significant speed variations on road segments with a precision of 68% and a recall of 84%.

Localizer Flight Technical Error measurement and uncertainty

Scipedia content — Thu, 28 Jan 2021 18:15:43 +0100

Recent United States Federal Aviation Administration (FAA) wake turbulence research conducted at the John A. Volpe National Transportation Systems Center (The Volpe Center) has continued to monitor the representative localizer Flight Technical Error (FTE) associated with Instrument Landing System (ILS) arrivals. This work complements, extends, and improves on previously published localizer FTE results by calculating FTE from more recent Airport Surface Detection Equipment — Model X (ASDE-X) datasets with improved data quality characteristics, as well as providing a quantification of the FTE measurement uncertainty due to the geometry of the Remote Unit (RU) sensor array that provides the analysis data. The technical description of the ASDE-X system is published as [1]. This paper presents additional FTE results and improved uncertainty calculations for ILS arrivals at John F. Kennedy International Airport (JFK) and Detroit Metropolitan Wayne County Airport (DTW), as well as comparisons with previous documented FTE results from Lambert — St. Louis International Airport (STL). The measurement uncertainty assessment provided insight on the level of confidence that can be placed in each runway specific dataset, and these localizer FTE results confirm the previously published observation that the observed FTE performance is consistently much tighter than the International Civil Aviation Organization (ICAO) navigation tolerances commonly used in safety simulations.

Modeling and Optimization of Terminal Airspace and Aircraft Arrival Subject To Weather Uncertainties

Scipedia content — Thu, 28 Jan 2021 18:10:34 +0100

We develop an accurate model for the arrival traffic dynamics in terminal airspace that takes into account the weather forecast and runway configuration changes. The planning of runway configuration switching subject to weather constraints is formulated as a hybrid optimal control problem and a hierarchical approach is proposed to solve the problem. At the upper level of the hierarchy, a runway configuration sequence is determined based on weather forecast data and air traffic demand. At the lower level, the configuration switching times and the corresponding aircraft speeds are determined by solving a Mixed Integer Linear Program. We illustrate the utility of the approach by a case study inspired by operations in John F. Kennedy airport.

The research input to the SINTROPHER project

Scipedia content — Thu, 28 Jan 2021 18:07:08 +0100

What is the added value of transnational cooperation for the development of transport solutions in North-Western Europe? To what extent are local stakeholders inspired by the experience and the knowledge gathered elsewhere? What are the benefits and the challenges of cooperation across national borders for the development of innovative transport solutions? The SINTROPHER project offers an excellent opportunity to address these issues and to contribute to recent academic and policy debates on the added value of transnational cooperation. Based on a comparative assessment of the development of new or improved tram projects in the five SINTROPHER partner regions, this study explores the added value of transnational cooperation for the diffusion and transfer of cost-effective transport solutions. 84294

Graph Decomposition in Risk Analysis and Sensor Placement for Water Distribution Network Security

Scipedia content — Thu, 28 Jan 2021 18:03:35 +0100

Over the last decade considerable research in water distribution network modeling has focused on the security of water supply against terrorist attacks. In this paper, specific issues of urban and regional distribution systems as to their vulnerability against terrorist attacks with CBRN (chemical, biological, radiological, nuclear) substances, detection methods and emergency plans are investigated. As a first step, a risk analysis is carried out based on topological properties of different parts of the network, classification of building developments and customers. The decomposition of the network graph enables the differentiation of network components (into treed components, blocks and bridges). Following this subdivision, the impacts and detection of attacks on various parts can be assessed. For example, looped parts (blocks) of the network are at a higher risk than branched subsystems (trees) since toxic matter can be distributed using alternate paths that depend on the particular water demand loading case whereas in a branched network only the system downstream the intrusion point is affected. The results of the risk analysis will be used for the creation of risk maps, efficient placement of sensors and the development of emergency plans. The specific differences of urban (mainly looped) and regional (mainly branched) supply networks will be demonstrated. The observation of water distribution systems with water quality sensors has been studied by researchers in detail over recent years. The application of the decomposition of the network graph to the sensor allocation problem will be demonstrated using the example network 2 of the Battle of the Water Sensor Networks (BWSN). The network is subdivided into tree, bridge and looped block components. It will turn out that tree structures should be excluded from application of sensor allocation algorithms using mathematical optimization since they are mostly responsible for non-detections. Decrease in calculation time can be further reached if separated blocks are identified in a preliminary analysis and the information is used for the solving the allocation problem. The crucial point of all sensor networks is that a full coverage of the system won’t be reachable and there will be a more or less long time to detection. An alarm is not actually generated until the toxic substance has passed a sensor. In this study another approach is proposed. The case of intrusion of the toxic substance by pumping against the pressure of the network will be considered. This event is considered as a “positive” leak. Leak detection methods that are normally used for the observation of pipelines are applied to the investigation of the water hammer event caused by the intrusion. Finally, conditions for the practical applicability of the method will be put up for discussion.

Modeling and simulation for user assistance in smart environments

Scipedia content — Thu, 28 Jan 2021 18:01:33 +0100

Smart environments are slowly but surely entering our everyday life. Their design provides many challenges. Not only heterogeneous devices acting and interacting in a dynamic environment but also intentions and activities of humans have to be taken into account. Diverse processes are responsible for achieving unobtrusive and pro-active user assistance. Those can be structured into a pipeline of perception, sensor interpretation, intention analysis, strategy synthesis, and actuation. Along this pipeline we analyze specific possibilities and requirements for modeling and simulation.

Performance analysis of urban road intersections and its environmental implication: a case study of the Lagos metropolitan area

Scipedia content — Thu, 28 Jan 2021 17:58:00 +0100

Urban road intersections are a major factor that influences the effectiveness of traffic flow systems. This paper is aimed at examining the performance of road intersections in the Lagos metropolitan area using the “Y-junction” of OgaIkorodu (Lagos, Nigeria) as the case study. The study examines the delay factors, time wastage and traffic conflicts. The study uses a reconnaissance survey, delay analytical tool, vehicle spot speed study and traffic volume survey to assess the level of delay, economic loss and traffic flow interruption. The study reveals that there are varying Levels of Service (LOS) obtainable at different times of the day on different carriageways, while Ayangburen Road records the best LOS of B in the morning, the afternoon and evening recorded C and D respectively. A different scenario holds for both Lagos and Sagamu as they record the worse LOS of E in the evening peak. In a related manner, the percentage of vehicle stoppage falls between 41.1%–87.8% indicating that vehicles tend to experience a stop scenario than not-stop at each approach especially during the peaks. It is therefore pertinent to note that the road intersection operates at a very low level of service especially during the evening peak when controlled by traffic wardens. It is therefore recommended that a Diamond-at-grade intersection be constructed in the area instead of the round-a-bout. The introduction of an automated traffic control system with full control of access and total removal of on-street parking will remove the road users’ burden in that area.

A Reservation-based Smart Parking System

Scipedia content — Thu, 28 Jan 2021 17:56:18 +0100

Finding a parking space in most metropolitan areas, especially during the rush hours, is difficult for drivers. The difficulty arises from not knowing where the available spaces may be at that time; even if known, many vehicles may pursue very limited parking spaces to cause serious traffic congestion. In this paper, we design and implement a prototype of Reservation-based Smart Parking System (RSPS) that allows drivers to effectively find and reserve the vacant parking spaces. By periodically learning the parking status from the sensor networks deployed in parking lots, the reservation service is affected by the change of physical parking status. The drivers are allowed to access this cyber-physical system with their personal communication devices. Furthermore, we study state-of-the-art parking policies in smart parking systems and compare their performance. The experiment results show that the proposed reservation-based parking policy has the potential to simplify the operations of parking systems, as well as alleviate traffic congestion caused by parking searching.

The need for change of the transport mode in the great cities of Romania

Scipedia content — Thu, 28 Jan 2021 17:42:45 +0100

This paper describes how the development of the great cities in Romania, especially the capital of Bucharest, and the dramatic rise in the number of cars has contributed to the pollution of these cities and resulted in horrific urban traffic, particularly during the morning and evening rush hours. To provide alternative transportation in Bucharest and the surrounding areas, Urban Transport Administration of Bucharest (RATB) uses 300 km of tram lines with a park of 500 tram wagons, 18 trolley lines with a 485 km network and a park of 300 trolleys, the bus transport system with a 2,900 km network and a park of 1,300 buses, 3 Light Rail (LR) lines and 4 subway lines. During rush hour, the tram and trolley lines are obstructed by cars most of the time, so the average transport speed is 6–9 km/h for trolleys and 8–10 km/h for trams. The travel time for cars is around 220,000 vehicles/hour, 18,000 vehicles/hour for cabs, and 854,000 passengers/hour for urban transportation with electrical vehicles and buses. The impact on the environment can be measured in noise levels, which for 2007 were estimated at 62.8 dB and very high polluting car emissions. This paper will examine the decision factors and the planning concerns to provide a more efficient urban transport in Bucharest and other great cities in Romania, especially with electric vehicles. The paper proposes a methodology to optimize the selection mode and the track design for LR, using existing tram lines with the necessary additions, the construction of new subway lines for the busy areas and the continuous development of the tram and trolley urban transportation network.

Power Electric Aiding Controller for Automated Bus Stopping

Scipedia content — Thu, 28 Jan 2021 17:40:35 +0100

Day by day the number of vehicles on roads is growing, increasing also the number of accidents, traffic jams and carbon dioxide emissions. For this reason, the European Union has adopted an action plan for improving urban mobility where the public transport is the main key. To present day, solutions as special bus lanes, electrical and hydrogen buses and rail-guided buses have been tested and implemented in several cities as London and Madrid. In this article an automated stopping system for electrical buses is presented. Stopping system have been implemented by the AUTOPIA program on an electric minibus and tested on a private circuit with satisfactory results.

Peer Reviewed

Understanding BGP next-hop diversity

Scipedia content — Thu, 28 Jan 2021 17:39:38 +0100

The Internet topological connectivity becomes denser over time. However the de facto routing protocol of the global Internet, BGP, lets each BGP router select and propagate only a single best path to each destination network. This leads to a common concern that the rich connectivity is not fully utilized and the lack of alternative paths can reduce a network's robustness to failures as well as flexibility in traffic engineering, and can lead to slow adaptation to topological changes. Yet there have been few quantitative measurement studies on path diversity in today's operational Internet. In this paper we use iBGP routing data collected from a Tier1 ISP, ISP A , over a 2-year time period to quantify BGP next-hop diversity for all destinations. Our results show that ISP A reaches the majority of prefixes through multiple next-hop routers. We use several case studies of prefixes with different diversity degrees to identify two major factors that impact the number of observed next-hops: the ISP's path preference and the number of peering routers between large ISPs. This observation provides operational input to the current efforts on augmenting BGP to increase path diversity.

Supporting air traffic control collaboration with a tabletop system

Scipedia content — Thu, 28 Jan 2021 17:34:39 +0100

International audience; Collaboration is key to safety and efficiency in Air Traffic Control. Legacy paper-based systems enable seamless and non-verbal collaboration, but trends in new software and hardware for ATC tend to separate controllers more and more, which hinders collaboration. This paper presents a new interactive system designed to support collaboration in ATC. We ran a series of interviews and workshops to identify collaborative situations in ATC. From this analysis, we derived a set of requirements to support collaboration: support mutual awareness, communication and coordination, dynamic task allocation and simultaneous use with more than two people. We designed a set of new interactive tools to fulfill the requirements, by using a multi-user tabletop surface, appropriate feedthrough, and reified and partially-accomplishable actions. Preliminary evaluation shows that feedthrough is important, users benefit from a number of tools to communicate and coordinate their actions, and the tabletop is actually usable by three people both in tightly coupled tasks and parallel, individual activities. At a higher level, we also found that co-location is not enough to generate mutual awareness if users are not engaged in meaningful collaboration.

Transport service of a cargo consolidation centre with respect to logistics service of urban agglomerations

Scipedia content — Thu, 28 Jan 2021 17:33:14 +0100

In the paper, a solution to a distribution system in an urban agglomeration, in which the transport service is performed by a Cargo Consolidation Centre (CCC), is presented. The model proposed in the paper aims at reducing cargo traffic in the urban area by coordinating traffic flows and eliminating empty runs. After reviewing the issues relating to distribution systems with reference to urban logistics, later in the article a mathematical approach to the supply problem was identified. Therefore, the formalization of input data, constraints, and criterion function notation was performed. On this basis, an optimization task for the distribution of goods in the urban agglomeration was formed. The final component of the paper is the presentation of solutions to the analysed case study, in which the problem was solved with the use of computer-aided methods.

Denver Water's Assessment of Interior Polyurethane Coating of 108 Inch Water Pipeline

Scipedia content — Thu, 28 Jan 2021 17:31:55 +0100

Fast set, high solids polyurethane has been used as a coating for the interior and exterior of steel water transmission pipelines since the late 1980s, but it wasn’t until 1999 that the American Water Works Association (AWWA) approved Standard C222 for polyurethane coating of steel pipe and fittings. Over the course of the following decade, the coating system gained wide acceptance for water transmission pipelines among many major water utilities. In 1997, Denver Water installed 8,090 lineal feet of 108-inch diameter steel water pipe with an interior coating of 20 mil thick polyurethane. As this was the utility’s first use of polyurethane, Denver Water has undertaken testing of the pipe polyurethane lining during scheduled shut downs of the pipeline in 1999, 2002, 2006, 2009 and 2011. This paper presents what Denver Water learned from its field inspection and testing program of this early-generation polyurethane lining system. Physical and visual testing has thus far yielded favorable results, proving the integrity of the polyurethane lining after fourteen years of service.

Gateway Traveler Information System: Regional Traveler Information Services

Scipedia content — Thu, 28 Jan 2021 17:31:21 +0100

The Gateway Traveler Information System (Gateway) and www.travelmidwest.com web site (formerly www.gcmtravel.com) provide timely, accurate, and useful traffic information to a variety of public and private constituents. Recurring and nonrecurring congestion directly impacts the economy, the environment, and the safety of the transportation network. The services and data provided by the Gateway have become a mission-critical service of the Illinois Department of Transportation (IDOT) and the geographically-connected roadway operators that are members of the Lake Michigan Interstate Gateway Alliance (LMIGA). This paper details the background and history of LMIGA and the Gateway, specifically www.travelmidwest.com. It highlights the goals of the Gateway and identifies four challenges and the associated resolutions that IDOT and the LMIGA partners use to ensure the Gateway is able to maximize the dissemination of quality traveler information to the staffs of operating agencies, the traveling public, and third party data subscribers. This paper also describes the elements that will impact both the system and the regional partnership as technologies advance, traveler information demands increase, and policies evolve.

Grid -Based Parallel Data Streaming implemented for the Gyrokinetic Toroidal Code

Scipedia content — Thu, 28 Jan 2021 17:25:58 +0100

We have developed a threaded parallel data streaming approach using Globus to transfer multi-terabyte simulation data from a remote supercomputer to the scientists home analysis/visualization cluster, as the simulation executes, with negligible overhead. Data transfer experiments show that this concurrent data transfer approach is more favorable compared with writing to local disk and then transferring this data to be post-processed. The present approach is conducive to using the grid to pipeline the simulation with post-processing and visualization. We have applied this method to the Gyrokinetic Toroidal Code (GTC), a 3-dimensional particle-in-cell code used to study micro-turbulence in magnetic confinement fusion from first principles plasma theory.

Flight management system execution of idle-thrust descents in operations

Scipedia content — Thu, 28 Jan 2021 17:25:03 +0100

To enable arriving aircraft to fly optimized descents computed by the flight management system (FMS) in congested airspace, ground automation must accurately predict descent trajectories. To support development of the trajectory predictor and its error models, commercial flights executed idle-thrust descents, and the recorded data includes the target speed profile and FMS intent trajectories. The FMS computes the intended descent path assuming idle thrust after top of descent (TOD), and any intervention by the controllers that alters the FMS execution of the descent is recorded so that such flights are discarded from the analysis. The horizontal flight path, cruise and meter fix altitudes, and actual TOD location are extracted from the radar data. Using more than 60 descents in Boeing 777 aircraft, the actual speeds are compared to the intended descent speed profile. In addition, three aspects of the accuracy of the FMS intent trajectory are analyzed: the meter fix crossing time, the TOD location, and the altitude at the meter fix. The actual TOD location is within 5 nmi of the intent location for over 95% of the descents. Roughly 90% of the time, the airspeed is within 0.01 of the target Mach number and within 10 KCAS of the target descent CAS, but the meter fix crossing time is only within 50 sec of the time computed by the FMS. Overall, the aircraft seem to be executing the descents as intended by the designers of the onboard automation.

Gaming concepts and incentives to change driver behaviour

Scipedia content — Thu, 28 Jan 2021 17:14:08 +0100

In this paper we present a novel concept that deals specifically with changing driver behaviour in order to reduce traffic congestion. The project I-GEAR (incentives and gaming environments for automobile routing) aims to understand the motivations that drivers have while undertaking the daily commute and then to provide them with a range of incentives to change their behaviour. A key focus within the project is on ways in which the problem could potentially be solved without recourse to an expensive infrastructure project. Our solution to this problem was to move the problem of traffic management onto everyday mobile devices. In the following paper we outline the background to the problem, concepts relating to pervasive gaming, existing explorations of incentives and gaming approaches as well as our basic concept and project methodology.

Interaction of airspace partitions and traffic flow management delay with weather

Scipedia content — Thu, 28 Jan 2021 16:57:47 +0100

The interaction of partitioning the airspace and delaying flights in the presence of convective weather is explored to study how re-partitioning the airspace can help reduce congestion and delay. Three approaches with varying complexities are employed to compute the ground delays. In the first approach, an airspace partition of 335 high-altitude sectors that is based on clear weather day traffic is used. Routes are then created to avoid regions of convective weather. With traffic flow management, this approach establishes the baseline with per-flight delay of 8.4 minutes. In the second approach, traffic flow management is used to select routes and assign departure delays such that only the airport capacity constraints are met. This results in 6.7 minutes of average departure delay. The airspace is then partitioned with a specified capacity. It is shown that airspace-capacity-induced delay can be reduced to zero at a cost of 20 percent more sectors for the examined scenario. While the first two approaches investigate the upper and lower bounds in terms of delay and number of sectors, the third approach investigates the tradeoff between the number of sectors and the delay by re-applying the traffic flow management using the re-partitioned sectors. In this approach, the weather constraints are reflected in the sector partitions, and the delay is shared between airspace and airports. The solutions discovered by this approach are 6.9 minutes of average delay with a 312 sector configuration and 8.1 minutes of delay with a 253 sector configuration. Results show that a sector design that is tailored to the traffic and weather pattern can reduce delay while reducing the number of sectors at the same time. However, airspace partitioning can only address the delays caused by airspace congestion. Even in the presence of convective weather, the airport capacity constraint causes the majority of the delay.

Planning with focus on pedestrians and sustainable transport in Pune, India

Scipedia content — Tue, 26 Jan 2021 18:23:45 +0100

The core city in Pune is highly congested, and the number of motorised vehicles on the street is increasing rapidly in the whole city. This creates problems like air pollution, high noise levels, long travelling times and an unpleasant urban environment etc. The thesis presents some solutions for these problems, based on sustainable transport principles, methods for creating a pleasant walking environment and best practice examples. The planning proposal is divided into a concept plan for the whole core city, as well as a detailed planning proposal for a pedestrian street on a part of Laxmi Road - one of Pune’s most well-known streets. Different aspects of the core city area and Laxmi Road have been mapped thoroughly and a traffic count, function analysis, a target point analysis and a Lynch analysis have been performed. Focus is to improve conditions for pedestrians. To achieve this it is important to limit the motorised traffic. An origin- destination survey performed on Laxmi Road displayed that over 40% of the traffic on the street in peak-hour is through traffic. The proposal is therefore to limit through traffic and improve the pedestrian environment. This thesis evaluates and discusses this proposal; including an analysis of the improvements to the air quality, the effect on different groups of people, and the necessary elements for the project to succeed.

Exploring techniques for the location and identification of potential users of urban public transportation

Scipedia content — Tue, 26 Jan 2021 18:22:43 +0100

Um dos objetivos dos projetos e estudos na área de transporte público é atrair o maior número possível de viagens. Um primeiro passo para estimular uma maior utilização do transporte público pode ser a captação de pessoas que já têm predisposição para utilizá-lo, mas que não o fazem por alguma deficiência específica no serviço. Este é o contexto no qual mapas que representam o potencial de utilização dos transportes públicos podem desempenhar um papel importante, como discutido neste estudo. A pesquisa tem como objetivo principal a aplicação e avaliação de duas técnicas destinadas a identificar potenciais usuários de transporte público e como estes se distribuem geograficamente em uma cidade brasileira selecionada para o estudo. Nas técnicas aqui exploradas, o município em análise é dividido em áreas em função do código de endereçamento postal. Estas áreas são caracterizadas pelos atributos socioeconômicos da sua população e do sistema de transporte. Diante da hipótese de melhoria na qualidade do transporte público, dois segmentos de usuários de automóvel foram determinados: usuários que trocariam para ônibus e usuários que ainda preferem o carro. Com isso, foi construído um modelo capaz de representar o comportamento de escolha dos usuários de cada área. A metodologia proposta envolve quatro passos: i) comparação de modelos Logit elaborados com dados de São Carlos (Brasil) e Wageningen (Holanda), ii) ajustes no modelo de São Carlos, iii) elaboração de um modelo de escolha modal por redes neurais artificiais e iv) elaboração dos mapas potenciais. As duas últimas etapas foram concebidas tanto para análises independentes, como também para comparação com o modelo Logit. Assim, a construção de cenários futuros permitiu identificar e localizar espacialmente os potenciais usuários de transporte público. Foi possível verificar também qual a influência de alguns atributos sobre a escolha do modo de transporte urbano. Por exemplo, usuários de domicílios com três ou quatro pessoas têm menor probabilidade de vir a utilizar o ônibus regularmente. Por fim, um cenário futuro tornou possível destacar áreas onde é esperado um aumento do potencial de uso do transporte público devido a mudanças nos valores de densidade populacional. One of the objectives of projects and studies on public transport is to attract the largest possible number of trips. A first step for increasing transit ridership may be the attraction of those individuals who already have a predisposition to use the service, but do not use it because of any specific inadequacies. This is the context in which maps displaying the potential use of public transport may play an important role, as discussed in this study. The research aims at the application and evaluation of two techniques used to identify potential users of public transport and to show how they are geographically distributed in a Brazilian city selected for the study. In the techniques discussed here, the municipality under analysis is divided into areas according to the postal codes of the streets. These areas are characterized by socioeconomic attributes of the population and of the transport system. Two segments of automobile users were determined, under the assumption that the quality of public transport would be improved: users who would switch to buses and users who still prefer the car. Based on that, a model designed to represent the choice behavior of users in each urban area was built. The proposed methodology involved four steps: i) the comparison of Logit models built with data of São Carlos (Brazil) and Wageningen (The Netherlands), ii) adjustments in the model of São Carlos, iii) the development of a mode choice model based on artificial neural networks, and iv) construction of potential maps. The third and fourth steps were meant for both independent analysis, and also for comparison with the Logit model. Thus, the construction of future scenarios allowed the identification and spatial location of potential users of public transport. It was also possible to learn about the influence of some attributes on urban transportation choice. For example, users living in households with three or four persons are less likely to become bus riders. Finally, a future scenario was able to highlight the areas where the potential for public transport could be increased due to changes in population density values.

Multiclass object recognition for driving assistance systems and video surveillance

Scipedia content — Tue, 26 Jan 2021 18:12:59 +0100

Co-encadrement de la thèse : Bogdan Stanciulescu; Pedestrian Detection and Traffic Sign Recognition (TSR) are important components of an Advanced Driver Assistance System (ADAS). This thesis presents two methods for eliminating false alarms in pedestrian detection applications and a novel three stage approach for TSR. Our TSR approch consists of a color segmentation, a shape detection and a content classification phase. The red color enhancement is improved by using an adaptive threshold. The performance of the K-d tree is augmented by introducing a spatial weighting. The Random Forests yield a classification accuracy of 97% on the German Traffic Sign Recognition Benchmark. Moreover, the processing and memory requirements are reduced by employing a feature space reduction. The classifiers attain an equally high classification rate using only a fraction of the feature dimension, selected using the Random Forest or Fisher's Criterion. This technique is also validated on two different multiclass benchmarks: ETH80 and Caltech 101. Further, in a static camera video surveillance application, the immobile false positives, such as trees and poles, are eliminated using the correlation measure over several frames. The recurring false alarms in the pedestrian detection in the scope of an embedded ADAS application are removed using a complementary tree filter.; La détection de piétons et la reconnaissance des panneaux routiers sont des fonctions importantes des systèmes d'aide à la conduite (anglais : Advanced Driver Assistance System - ADAS). Une nouvelle approche pour la reconnaissance des panneaux et deux méthodes d'élimination de fausses alarmes dans des applications de détection de piétons sont présentées dans cette thèse. Notre approche de reconnaissance de panneaux consiste en trois phases: une segmentation de couleurs, une détection de formes et une classification du contenu. Le color enhancement des régions rouges est amélioré en introduisant un seuil adaptatif. Dans la phase de classification, la performance du K-d tree est augmentée en utilisant un poids spatial. Les Random Forests obtiennent un taux de classification de 97% sur le benchmark allemand de la reconnaissance des panneaux routiers (German Traffic Sign Recognition Benchmark). Les besoins en mémoire et calcul sont réduits en employant une réduction de la dimension des caractéristiques. Les classifieurs atteignent un taux de classification aussi haut qu'avec une fraction de la dimension des caractéristiques, selectionée en utilisant des Random Forests ou Fisher's Crtierion. Cette technique est validée sur deux benchmarks d'images multiclasses : ETH80 et Caltech 101. Dans une application de vidéo surveillance avec des caméras statiques, les fausses alarmes des objets fixes, comme les arbres et les lampadaires, sont éliminées avec la corrélation sur plusieurs trames. Les fausses alarmes récurrentes sont supprimées par un filtre complémentaire en forme d'arbre.

Bağ Yolculuk Sürelerinin Ölçüm Ve Modelleme Kapsamında İrdelenmesi

Scipedia content — Tue, 26 Jan 2021 18:12:28 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012

Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2012

Ulaştırma mühendisliği açısından temel bir ölçü olan ‘yolculuk süresi’ kavramı; kullanıcılar, yöneticiler ve ulaştırma mühendisleri gibi geniş bir kitle tarafından en kolay anlaşılan ve belirlenebilen bir ölçüttür. Hem başarım ölçütü olarak hem de kullanıcıların güzergâh seçim karar verme aşamasında önemli bir yeri olan yolculuk süresi, akıllı ulaştırma sistemleri uygulamalarında kullanıcılara çevirim içi bilgi sağlamak amacıyla da kullanılmaktadır. Bu çalışma ile yolculuk süresi türetme yöntemlerinin en doğru şekilde kullanılmasıyla, kullanıcılara sunulan yolculuk süresi kestirimindeki doğruluk payını arttırmak hedeflenmiştir. Ulaştırma sistemlerinin temel amacının kullanıcılara fayda sağlamak olduğu düşünüldüğünde, özellikle iş ve okul yolculukları gibi zirve saat trafiğinin büyük bir kısmını oluşturan yolculuklarda, yolculuk süresinin belli sınırlar içerisinde kalması gerektiği görülür. Ulaştırma sistemi kullanıcıları için bu derece rijit bir yapısı olan yolculuk süresi, plansız büyüyen ve karayolu ulaştırması baskın kentsel alanlar söz konusu olduğunda, katlanılamaz seviyelere çıkmaktadır. Güncel ekonomik gelişmelerle eşzamanlı olarak artan ve farklılaşan hizmet türleri ile bunların seçeneklerinin, planlama politikalarından yoksun biçimde arazi kullanımına etkimesi sonucu, dengesiz ve abartılmış trafik talebi meydana gelmekte, ayrıca nüfus artışı gibi demografik özelliklerin değişimi karşısında ulaştırma sistemi altyapısı da yetersiz kalabilmekte ve dolayısıyla çözülemez tıkanıklıklara neden olmaktadır. Bu çalışmada; yolculuk sürelerinin, ölçüm yöntemleri ve trafik algılayıcıları verilerinden türetilmesi üzerinde yoğunlaşılmış, yolculuk süresi kestirim sürecine yönelik bir yaklaşım önerilmiş ve gerçek hayattaki olası uygulama alanlarından bahsedilmiştir. Yolculuk sürelerinin türetimi ve kestirimi arasındaki ayrım ortaya konarak, türetim/modelleme kapsamında yapılan çalışmalar irdelenmiştir. Seçilen farklı yöntemlerle türetilen yolculuk süreleri, gerçek yolculuk süreleri ile karşılaştırılmıştır. Trafik akım dinamiklerinin anlatıldığı bölüm sonrası yolculuk süresinin doğrudan türetilmesi, başka bir deyişle gelişmiş teknolojiler yardımıyla ölçülmesi anlatılmıştır. Bu yöntemlerden küresel konumlandırma sistemi (KKS) donanımlı gözlem aracı ve Bluetooth trafik algılayıcılarından faydalanarak alan çalışması ile yolculuk süresi ölçümleri gerçekleştirilmiştir. Yolculuk süresinin türetilmesinde kullanılan yörünge temelli yöntemler, trafik akım kuramı temelli yöntemler ve diğer yöntemler, ilgili temel çalışmalara değinilerek ayrıntılı biçimde irdelenmiştir. Çalışmada da kullanılan, sabit ve değişken hız varsayımlı yörünge temelli yöntemler ile yolculuk süresinin türetimine ilişkin ayrıntılı açıklamalara yer verilmiştir. Yolculuk süresi türetim duyarlılığını arttırmak için, trafik akımının dinamik özelliğini dikkate alan yaklaşımlardan bahsedilmiştir. Kullanılan kaba-boyut ve ince-boyut modellerin kuramsal yapıları, girdi verisi olarak kullanılan değişkenler ve modelleme için yapılan varsayımlar açıklanmış ve elde edilen sonuçlar irdelenmiştir. Yolculuk süresi çalışmaları için ince-boyut benzetim modelinden var olan bir yazılımla (Vissim); kaba-boyut modelden ise kuramsal yapısının kodlanması ile faydalanılmıştır. Kaba boyut model olarak Friesz ve diğerlerinin doğrusal yolculuk süresi modeli kullanılmıştır. Gün-içi yolculuk sürelerinin dağılımını belirleyebilmek için ağ modellerinde sıkça faydalanılan bu model ile yolculuk sürelerini akşam ve sabah zirve saatleri için hesaplanmıştır. İstanbul TEM Otoyolu üzerinde belirlenen çalışma güzergâhında mikrodalga trafik algılayıcıları ile toplanan trafik akım verisi kullanılarak, ince-boyut akım modelinin benzetildiği yazılımın kalibrasyonu yapılmıştır. İnce-boyut benzetim modelinde gerçek konumlarına yerleştirilen trafik algılayıcılarıyla trafik akımına ait tekrar üretilen veriler, belirli bir zaman aralığında toplulaştırılmıştır. Yeniden üretilen algılayıcı verileri ile yörünge temelli yöntemler kullanılarak bağlar için yolculuk süreleri türetilmiştir. Katılma ve ayrılma bölgesinin olmadığı çalışma güzergâhı, ince-boyut benzetim modelinde, çalışma için oluşturulan bağların öncesinde ve sonrasında bulunan, Ümraniye ve Kavacık Kavşağı’nı kapsayan bir alan boyunca modellenmiştir. Temmuz 2011 ve Ocak 2012 tarihlerinde belirlenen bir hafta boyunca, çalışma güzergâhında KKS donanımlı gözlem aracı ile yolculuk süresi ölçümleri gerçekleştirilmiştir. Ayrıca, Ocak 2012 ölçüm haftasında KKS ile eş zamanlı olarak Bluetooth trafik algılayıcıları kullanılarak da yolculuk süreleri ölçülmüştür. Yörünge temelli yöntemler ile türetilen yolculuk süreleri, ince-boyut benzetim yazılımından elde edilen yolculuk süreleriyle karşılaştırılmıştır. Gerçek yolculuk süreleriyle ekstrapolasyon yöntemleriyle türetilen yolculuk sürelerinin istatistiksel analizleri yapılarak başarımları sınanmıştır. KKS donanımlı gözlem aracıyla ölçülen gerçek yolculuk süreleri; ince-boyut benzetim modelinden elde edilen ve Friesz ve diğerlerinin doğrusal yolculuk süresi modeli ile hesaplanan yolculuk süreleriyle karşılaştırılmıştır. Her iki model sonucunun, yolculuk süresi türetimindeki başarımları değerlendirilmiştir. Gerçek yolculuk süresi bilgisi, mikrodalga trafik algılayıcıları gibi yol kenarına yerleştirilen Bluetooth trafik algılayıcıları ile ölçülebilir. KKS ile taşıtlardan sağlanan verilerin bir merkez istasyona aktarılmasıyla, yolculuk süresi ve hız gibi bilgiler yüksek duyarlılıkla ve çevirim içi belirlenebilir. Daha basit bir yaklaşımla, yol boyunca belirli kesitlere yerleştirilen trafik algılayıcılarından elde edilen taşıt sayıları kullanılarak; yol kesiminin kapasite, tıkanıklık yoğunluğu ve şerit sayısı gibi özellikleri göz önüne alınarak, yolculuk süresi, matematik yöntemlerle de türetilebilir. Türetilen yolculuk süreleri, var olan trafik koşularının değişmeyeceği varsayımıyla bağ yolculuk süreleri hakkında bilgi sağlamaktadırlar. Gerçekte ise kullanıcı, güzergâhını tamamlayana kadar akım koşullarında değişiklik meydana gelebilir. Bu da, var olan akım koşulları için türetilen yolculuk süresi ile kısa bir süre sonra gerçekleştirilecek olan yolculuğun süresi arasında farka yol açabilmektedir. Bu nedenle kullanıcılar için yolculuk süresinin türetimi yerine, kısa bir süre sonraki zaman aralıklarına dair yolculuk süresi kestirimi daha fazla yarar sağlayabilir. Yolculuk süresi kestirim süreci, trafik algılayıcılarından elde edilen gerçek zamanlı ve geçmiş trafik akımına ait verilerle akıllı ulaştırma sistemlerinin bir bileşeni olarak uygulanabilir. Trafik akımına ait geçmiş veriler, Bluetooth trafik algılayıcılarıyla ve KKS donanımlı araçlarla ölçülen yolculuk süresi bilgileriyle birlikte kullanılarak, gerçek zamanlı elde edilen trafik algılayıcı verileriyle yolculuk süresi kestirimi yapılabilir. Tüm bu yöntemlerin bileşeni olduğu yolculuk süresi kestirimi süreciyle elde edilen değerler, kullanıcılara, güzergâh seçimlerinde kullanmaları için çevirim içi olarak sunulabilir. Böylece, özellikle yoğun kentsel alanlarda, kullanıcılar güzergah seçerken uzaklık bilgisinin yanında yolculuk süresi bilgisini de göz önünde bulundurabilirler. Trafik akımının dinamik özelliğini dikkate alarak ve var olan teknolojilerden en uygun biçimde faydalanarak kullanıcılara en doğru yolculuk süresi bilgisi sunabilmek, güzergâh seçimi ve kullanıcıların ulaştırma sisteminden elde edeceği faydayı enbüyüklemek bakımından önemlidir. Bu nedenle, özellikle kent içi karayolu ağlarında, talebin yoğun olduğu bölgelerde kullanıcılara sunulan yolculuk süresi bilgisinin önemi daha da artmaktadır.

The basic purpose of a transportation system is to maximize the utility of its users. Considering that the travel time measure should be kept in certain limits especially for the trips comprising a large amount of the peak hour traffic, such as home based school trips and home based work trips, this measure becomes intolerable for system users where the cities grow unplanned with a road-dependent transportation. ‘Travel time’ which is a basic concept in terms of transportation engineering is the most apparent and identifiable quantity that can be easily understood by a large mass of people such as users, administrators, and transportation engineers. The travel time is an important measure, both as a performance indicator and a route choice decision variable, and can be used for the purpose of providing online information in Intelligent Transportation Systems applications. The motivation of the present study is to justify the accurate use of the travel time estimation (or reconstruction) methods which consequently yields to increases on the accuracy of travel time prediction. In this study; estimation approaches on travel time and relevant reconstructions based on traffic detector data is focused. An approach related to travel time prediction process and its possible application fields in real life are suggested. By introducing the difference between travel time estimation and prediction, studies within estimation/modelling are examined. Reconstructed travel times and real values are compared with the selected different methods. After the chapter related to traffic flow dynamics are represented, direct reconstruction of travel times, in other words, reconstruction with measuring methods by means of advanced technology is explained. The field study on travel time measurement is carried out utilizing a Global Positioning System (GPS) equipped observation tool and a Bluetooth traffic detector. Travel time reconstruction methods including trajectory methods, methods based on traffic flow theory and other methods are reviewed referring to both fundamental and relevant specific studies. The trajectory methods selected for reconstruction performance analyses, i.e., the hypothetical constant and the variable speed based methods, are explained in details. In order to increase travel time reconstruction accuracy, approaches considering the dynamic features of traffic flow are also reviewed. The theoretical structure of the macroscopic and microscopic models used and assumptions for modelling are explained preceding the evaluation of results obtained. In reconstruction studies; microscopic modelling approach is employed using an existing commercial simulation software (PTV AG VISSIM) and macroscopic modelling approach is employed by coding its theoretical structure. As the macroscopic model, linear travel time function based model of Friesz et al has been utilized. Travel time distributions are sought considering evening and morning peak hours in order to figure out the daily variation of travel time for network-wide purposes. The calibration of microscopic simulation software is done by sourcing data collected by microwave traffic sensors at specified links on İstanbul Trans European Motorway (TEM). Traffic flow data obtained at microwave sensors are utilized locating sensors to actual locations in the microscopic simulation model. Following, traffic flow data is reproduced in specified time intervals. Travel time is reconstructed according to trajectory methods for links by using sensor data which are reproduced in microscopic simulation. In microscopic simulation model, the study links without merges and diverges are modelled in an area bounded by Ümraniye and Kavacık Junctions. On one hand, travel time measurements are carried out with a GPS equipped probe vehicle on the freeway route of our interest throughout one week s time both in June 2011 and in January 2012. On the other hand, travel times are alternatively measured by Bluetooth traffic detectors; those are processed simultaneously with probe vehicle measurements in January 2012. Travel times reconstructed by trajectory methods are compared with the travel times obtained by the microscopic simulation software. Statistical analyses are carried out to justify the performance of travel time reconstructions with respect to actual measurements. Travel times can be accurately measured by using Bluetooth traffic detectors that may be easily fixed to roadsides just as other types of traffic detectors/sensors. Travel times can be alternatively reconstructed by indirect methods such as mathematical models. Assuming that existing traffic flow condition is stationary, reconstructed travel times provide information on link travel times. In practice there may be variations on flow conditions while a user is traversing a route. This may yield to mismatching between the reconstructed travel time for actual situation and the travel time to be experienced in short-term. Therefore, information provision by short-term travel time predictions is more benefical for users than the information of reconstructed travel times. Travel time prediction can be performed as a part of intelligent transportation systems applications by using real-time and historical traffic detector data. Historical measurements on travel times obtained by Bluetooth detectors and GPS equipped probe vehicles can be used to reconstruct, in a meaning to calibrate, a model and feeding this model with real-time traffic data enables a prediction process. Measures resulting from travel time prediction process that incorporates all the methods of measurement and reconstruction may be disseminated to users online via intelligent systems so that interactive decision makings relying on current flow conditions can be made. Therefore, especially in dense urban areas, users can be able to consider travel time information in addition to the length of the trip. Accurate and reliable travel time information dissemination to users by using the existing technology appropriately and considering the dynamic features of traffic flow is substantial to maintain route choice decisions that consequently yield to maximization in users utilities on a transportation system. Therefore, the importance of travel time information dissemination to users increases especially in urban road networks and in areas where the demand is high.

Yüksek Lisans

M.Sc.

Relationship between air transport and tourism in Norway

Scipedia content — Tue, 26 Jan 2021 17:53:56 +0100

Kentiçi Ulaşımda Bisikletin Konumu Ve Şehirler İçin Bisiklet Ulaşımı Planlaması: Sakarya Örneği

Scipedia content — Tue, 26 Jan 2021 17:37:07 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012

Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2012

Günümüzde kentlerin yaşadığı en büyük sorunlar ulaşım kaynaklıdır. Kentsel nüfusun artması, kentlerin plansız genişlemesi ve motorlu araç kullanımının fazlalaşması sonucunda hem insan sağlığını hem de kent hayatını olumsuz etkileyen ve yaşam kalitesini düşüren pek çok sorun ortaya çıkmıştır. Sağlıklı, ekonomik, hızlı, eğlenceli ve çevre dostu bir ulaşım türü olan bisiklet ulaşımı, bu sorunlara etkili bir çözüm olmakta ve sürdürülebilir ulaşım konseptine çok uygun düşmektedir. Özellikle kısa mesafeler için bisiklet otomobilin yerini alma potansiyeline sahiptir. Dünyada Hollanda, Danimarka, Japonya gibi güçlü bir bisiklet kültürüne ve yüksek bisiklet kullanım oranlarına sahip ülkeler bulunmaktadır. Türkiye’de ise bisiklet bir ulaşım türü olarak fazla tercih edilmemekte, yaygın olarak kullanılmamaktadır. Bu çalışmada Türkiye’de bisiklet ulaşımının bugünkü durumuyla ilgili genel değerlendirmeler yapılmış, yapılan anket çalışmalarıyla Türkiye’deki bisiklet kullanıcılarının profili belirlenmiştir. Orta ölçekli şehirler için bisiklet yolu planlamasının aşamaları anlatılmış ve Sakarya şehrinde yapılan bir planlama çalışması gösterilmiştir. Trafik kaza verileri kullanılarak bisikletliler için bir yol güvenliği analizi yapılmış ve Sakarya’da planlanan yolun sağlık açısından getireceği faydanın ekonomik değeri hesaplanmıştır. Türkiye’de bisiklet ulaşımının geliştirilebilmesi için hedef ve stratejiler belirlenmiş ve proje önerilerinde bulunulmuştur. Çalışmanın, bisiklet ulaşımı ile ilgili bundan sonra yapılacak çalışmalar için yol gösterici olması hedeflenmiştir.

Today, the biggest problems that cities face are transportation based. The rapid population growth, urban sprawl and fast motorization created many problems that effect human health and city life and decrease the quality of life. As a healthy, cheap, fast, fun and clean mode of transportation, cycling is an effective solution to these problems and fits very well into the sustainable transportation concept. Bicycle has the potential to take the place of cars especially for short distances. Some countries such as Netherlands, Denmark and Japan have strong cycling culture and relatively high cycling mode shares. However, in Turkey, cycling is not seen as a transportation mode both by the public and the authorities and it is not preferred that much. In this study, an overall assessment of the current state of cycling in Turkish cities is made and with the results of surveys conducted in cities, the profile of cyclists in Turkey is formed. The steps of bicycle transportation planning for mid-size cities are told and a planning study made for the City of Sakarya is shown as an example. By using traffic accident data, a road safety analysis for cyclists is made and the economical appraisal of the health effects related to increased cycling for the planned cycle route in Sakarya is calculated. The targets and strategies are defined and some projects are suggested to increase the awareness and the level of cycling in Turkish cities. It is intended for this study to become a good source for future studies.

Yüksek Lisans

M.Sc.

How to increase the market share of public transportation? Experiences from the city of Göteborg.

Scipedia content — Tue, 26 Jan 2021 17:36:27 +0100

The paper focuses on measures for a process of increasing the market share of public transportation in the case of the city of Göteborg. Based on a general discussion of the question how people behave in terms of traveling by public transportation or car and the theoretical framework sorting different groups of measures of push and pull factors, a presentation of the use of measures in the case of the city of Göteborg leads to the development of possible first steps. Literature about travel behavior in theory and case studies offers background for concepts for reducing car use like Motility and Travel Demand Management as well as for the concept of push and pull factors. Interviews made with experts working with public transportation in the city of Göteborg help to get an overview of several opinions about the implementation of different groups of measures. The main findings are the strengths and weaknesses of the key theoretical issues as well as the experience already made with projects for increasing market share of the city of Göteborg. When being aware of the findings, one can conclude that the communication and cooperation among others between institutions and organizations has to get intensified to increase the market share of public transportation in the case of the city of Göteborg. Moreover for a successful process it is necessary to minimize the lack of research and the policy has to consist of both soft and hard measures of push and pull factors as the combination includes more target groups and matches the reality of practice.

Electromobility in Sweden : Facilitating market conditions to encourage consumer uptake of electric vehicles

Scipedia content — Tue, 26 Jan 2021 17:34:34 +0100

The impact of traffic noise pollution on the population of Strubensvalley in Roodepoort

Scipedia content — Tue, 26 Jan 2021 17:23:07 +0100

M.Sc. The Strubensvalley area is an up market area with numerous shopping centres and trendy dwellings. A major road, namely Hendrik Potgieter Road (M47), feeding between Johannesburg and North West/Botswana, runs through the suburb. Residents of Strubensvalley are in their concern about this road: the noise pollution which impacts negatively on their lives. This research investigates the traffic noise and the impact it has on the population of Strubensvalley.The selected study area was delimited by drawing a circle with a radius of four kilometers around the middle point, it being at the intersection of Hendrik Potgieter Road and Krugerrand Road. Clearwater Mall and Wilgeheuwel Retail Crossing shopping centre are the two large features on the circumference of the study area. A calibrated sound level meter was used to measure the traffic noise at 18 different measuring points within the study area. Measurements were taken during the day (6am to 10pm) and at night (10pm-6am) in order to establish the noise impact caused by the peak flow and non-peak flow of traffic in the suburb. A 30-item noise -health-related questionnaire was used to establish the impact of traffic noise on the respondents. A hundred randomly -chosen participants within the study area were interviewed on a door-to-door basis. On completion of this research, it was established that the people interviewed were generally annoyed by the traffic noise in Hendrik Potgieter Road. The majority of the participants complained about the annoyance and interference factor caused by traffic noise in that it affected them in activities (e.g. napping during the day).

Carrier selection criteria for Scandinavian domestic road transport : A study of the competition between Scandinavian and Eastern European hauliers in a scenario without restrictions on cabotage

Scipedia content — Tue, 26 Jan 2021 16:42:13 +0100

The European Commission has for some time indicated a desire to remove the remaining restrictions on cabotage. Such liberalization is expected to result in significant changes on some domestic road transport markets. The Scandinavian markets are among these and the local hauilers fear that the lower wages of Easter European hauliers will leave them out of business. In this thesis a scenario of full cabotage liberalization is assumed. Representatives from associations with interest within the Scandinavian road transport markets has been approached with a qualitative survey on carrier selection criteria. Respondents are asked to determine the importance of the criteria, as well as the relevance to the competition between Scandinavian and Eastern European hauliers. Finally they are asked to assess whether the advantage of each criterion lies with Scandinavian or Eastern European hauliers. The qualitative orientation of the survey is achieved though justification and follow up questions. Reliability of pickups and deliveries is still regarded the most important criteria. Also competitive prices received a high rating. It is concluded that the significant price difference between Scandinavian and Eastern European hauliers will benefit Eastern European hauliers considerably in the competition for the simple “from A to B” shipments. For more complicated shipments, entailing a higher level of service, communication and supply chain integration, the local hauliers are expected to stand their ground.

Developing a neural network modeling framework for a trip distribution model

Scipedia content — Tue, 26 Jan 2021 16:36:11 +0100

Thesis (PhD)--University of South Australia, 2012. Includes bibliographical references. Trip distribution forecasting has been undertaken by using the gravity model for more than four decades. Literature review suggests that traffic forecasts can be overestimated up to 60 per cent above the actual numbers. Underestimated traffic forecasts are also found, with an average of 21.3 per cent below the actual numbers. Thus, a question emerges: Has traffic forecasting become more accurate over the last four decades? In fact the literature indicates that traffic forecasts have not improved over the last 30-years. Thus, a new, transparent and accountable forecasting method is recommended in order to prevent more severe financial risk and perhaps more damage to social and economic welfare. This research proposes a trip distribution modelling framework using the neural network approach. Although neural networks have been used in trip distribution modelling for more than two decades, the forecasting capability is not yet optimally explored and understood. This is due to its performance being dependent on multiple properties. It requires working in an integrated system in solving various tasks, including the forecasting task. This research focuses on the development of that integrated system by considering the internal and external factors related to the neural network approach and the characteristics of fully constrained spatial distribution models. Therefore, the capability of neural network approach in forecasting spatial distribution can be optimized. The gravity model forecasts the trip distribution numbers by using a specific deterrence function and also, on occasions, by incorporating socioeconomic adjustment factors (K-factor). It theoretically assumes that the trip number increases when the deterrence variable decreases, and vice versa. Then, the K-factor is incorporated in the gravity model so that it generates more accurate results. Reliance on these functions and factors is considered as one of the weaknesses of the gravity model. Firstly, the assumption related to the deterrence variable is not always true. Secondly, the mechanism of K-factor is unclear and it is difficult to estimate its future values. Thirdly, collecting the data for estimating the K-factor is difficult, time consuming, and costly. Meanwhile, the neural network approach for spatial distribution forecasting works by capturing the relationship between independent and dependent variables without reliance on any function representing the relationship between these variables. It also works without requiring additional data representing the socioeconomic adjustment factor. It forecasts the trip distribution numbers through a learning process and generalizes the trip numbers based on that relationship. Therefore, more accurate estimation of trip numbers is expected. This is demonstrated by application of the proposed framework. The calibration and generalization performance of the neural model for passenger travel and commodity flow are found to be superior to the doubly constrained gravity model. About 88 per cent of the neural models have lower error and higher goodness-of-fit than the gravity model. About 75 per cent of the neural models significantly outperform the gravity model for passenger trip distribution forecasting, while this is about 63 per cent for commodity flow distribution. Another benefit of the proposed framework is it can be used for any number of traffic analysis zones.

A web-based system for comparative analysis of OpenStreetMap data by the use of CouchDB

Scipedia content — Tue, 26 Jan 2021 16:30:01 +0100

Markus Mayr Wien, Techn. Univ., Dipl.-Arb., 2012

Otomatik Ücretlendirme Sistemi Verileri Kullanılarak İstanbul Geneli Toplu Taşıma Başlangıç – Son Matrisi Tahmini İçin Bir Yöntem

Scipedia content — Tue, 26 Jan 2021 15:56:35 +0100

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012

Thesis (PhD) -- İstanbul Technical University, Institute of Science and Technology, 2012

Bu çalışmada, İstanbul toplu taşıma sistemi için otomatik ücretlendirme sistemi verileri kullanılarak, Başlangıç-Son Matrisi tahmini için bir yöntem geliştirilmiştir. Çalışma kapsamında, anket verileri ile elde edilen B-S Matrisi de incelenmiş olup; her iki yöntem arasındaki farklılıklar, avantaj ve dezavantajlar ortaya konulmaktadır. Toplu taşımacılık literatürü incelendiğinde, konu ile ilgili benzer çalışmalara rastlanmaktadır. Ancak, bu çalışmanın diğer çalışmalardan en önemli farklarından birisi, incelenen sistemdeki toplu ulaşım araçlarında GPS cihazları bulunmadığından, araç konumlarının tespiti için bir yöntem tariflenmesidir. Diğeri ise çalışma sonucunda elde edilen yolculukların ağırlıklandırılması için yeni bir uygulama geliştirilmesidir. Araç konumlarının tespiti için önerilen yöntemde, akıllı kart verileri ile kent genelinde bir günde gerçekleşen tüm araç kalkış verileri zaman parametresi dikkate alınarak ilişkilendirilmektedir. Araç konumlarının tespiti ile yolculuk başlangıç noktaları da belirlenmiş olmaktadır. Yolculuk kavramının tariflenmesiyle birlikte, yolculuk bitiş noktalarının tespiti için önerilen yöntem de aşamalar halinde açıklanmaktadır. Tahmin işlemlerinin son aşamasında, İstanbul genelinde elde edilen toplu ulaşım yolculukları ağırlıklandırılarak gerçekleşen değerlerle uyumlu hale getirilmektedir. Toplu ulaşım B-S Matrisi tahmin çalışmaları tamamlandıktan sonra, 2006 yılı anket verileri analiziyle elde edilen B-S Matrisi ile karşılaştırma yapılmaktadır. Sonuç kısmında, İstanbul genelindeki ana ulaşım akslarından seçilen kesitlerdeki toplu ulaşım yolculuk hacimlerinin ve bölgesel bazda yolculuk üretim değerlerinin karşılaştırılmasıyla ilgili sonuçlarından bahsedilerek; mevcut sistem için yapılan önerilerle birlikte, ileride yapılacak benzer çalışmalar için de tavsiyelerde bulunulmaktadır.

In this study a method is developed for the estimation of O-D Matrix, using automated fare collection system data for the public transportation system in İstanbul. Within the scope of this study, O-D Matrix which is obtained from survey data is analyzed and differences between two methods also advantages and disadvantages are stated. It is possible to find similar studies if public transportation literature is searched. However, one of the most important difference of this study from the similar ones is developing a method to determine vehicle coordinates without using GPS devices; because there is no GPS devices in that public busses. The other one is developing a new method for the weighting journeys which are obtained from smart card data study. In the proposal method of determining vehicle coordinates, smart card data is associated with vehicle departure data of a day city-wide with considering time parameter. Vehicle departure point is also designated according to the vehicle coordinates. After defining the journey concept, the methods of confirming destination point of journey is also explained step by step. In the last stage of the estimation operations, public transportation journeys throughout İstanbul are weighted, and the results are aligned with the realized values. After finalizing estimation of public transportation O-D Matrix, it is compared with O-D Matrix which is obtained from survey data in the year of 2006. Finally, the results of comparison between, public transportation journey volume at the chosen section of major transportation axis and zone based trip production value is given; then some proposals is presented for the existing system and also for similar studies in the future.

Doktora

PhD

Analysis of Potential Wake Turbulence Encounters in Current and NextGen Flight Operations

Scipedia content — Tue, 26 Jan 2021 15:50:17 +0100

Wake vortices pose a threat to a following aircraft, because they can induce a roll and compromise the safety of everyone on board. Caused by a difference in pressure between the upper and the lower part of the wings, these invisible flows of air are a major hazard and have to be avoided by separating the aircraft at considerable distances. One of the known constraints in airport capacity for both departure and arrival operations is the large headway resulting from the wake spacing separation criteria. Reducing wake vortex separations to a safe level between successive aircraft can increase capacity in the National Airspace System (NAS) with corresponding savings in delay times. One of the main goals of the Wake Encounter Model (WEM) described in this thesis is to assess the outcome from future reduced separation criteria in the NAS. The model has been used to test probable encounters in todayâ s operations, and can also be used to test NextGen scenarios, such as Close Parallel Approaches and reduced in-trail separation flights. This thesis presents model enhancements to account for aircraft turning maneuvers, giving the wake a more realistic shape. Three major airspaces, New York, Southern California and Atlanta, were analyzed using the original and the enhanced WEM to determine if the enhanced model better represents the conditions in todayâ s operations. Additionally, some analysis on the wake lateral travel for closely spaced runways is presented in this thesis. Finally, some extension tools for post -analysis, such as animation tool and various graphs depicting the interactions between wake pairs were developed. Master of Science

Metodologias de dimensionamento e de gestão de fontes de energia para veículos elétricos

Scipedia content — Tue, 26 Jan 2021 15:47:12 +0100

Orientadores: José Antenor Pomílio, Paulo Augusto Valente Ferreira Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Made available in DSpace on 2018-08-21T18:08:46Z (GMT). No. of bitstreams: 1 Lopes_Juliana_D.pdf: 4449878 bytes, checksum: 6f40b7bd3dbcac957967155e2c1e966e (MD5) Previous issue date: 2012 Resumo: O sistema de armazenamento de energia (ESS - Energy-Storage System), em veículos elétricos, constituído por baterias e/ou supercapacitores pode agregar elevado custo ou elevada massa ao veículo caso o número de módulos dessas fontes seja inadequado. Nesta Tese são propostas duas metodologias aplicadas ao dimensionamento da ESS a fim de encontrar configurações de menor massa possível. Essas configurações devem ser capazes de suprir energia para o veículo elétrico em um dado perfil de alto valor de potência requerida. São investigadas ESSs com diferentes tipos de baterias e supercapacitores a fim de se obter um amplo range de escolhas de configurações em relação a peso e custo. Além de uma unidade ESS o veículo possui uma fonte de autonomia que pode ser uma célula a combustível ou uma unidade gerador/motor à combustão interna. A primeira metodologia de dimensionamento investiga configurações de ESS híbridas ou constituídas apenas por baterias ou supercapacitores para um veículo do tipo Sport Utility Vehicle. Esta metodologia utiliza os coeficientes de potência e energia específicas a partir das curvas de Ragone das fontes da ESS. Os resultados mostraram, que, dentre as configurações de ESSs investigadas, que a de menor massa é constituída apenas por supercapacitores de 165 F. A segunda metodologia de dimensionamento investiga configurações de ESSs híbridas para três tipos de veículos: um Sport Utility Vehicle, um micro-ônibus e ônibus de transporte urbano. Esse estudo visa mostrar a viabilidade do emprego da metodologia a veículos com diferentes aspectos físicos. Esta metodologia de dimensionamento destaca-se pela utilização de otimização não Linear na solução do problema cuja função objetivo é a menor massa da ESS. O aspecto inovador desta metodologia está na utilização de otimização na solução do problema referente ao dimensionamento da ESS aplicado ao envelope dos perfis de potência dos ciclos de condução. O envelope é resultante da sobreposição dos perfis de potência relativos aos ciclos de condução de operação dos veículos. O objetivo em utilizar o envelope dos perfis de potência está na abrangência de situações diversas de operação, em eventuais ciclos de condução, nos quais o veículo possa ser conduzido. A metodologia é aplicada a determinados períodos do envelope com alto valor de potência requerida. São propostas duas estratégias de gerenciamento de potência a fim de verificar a atuação entre a ESS, dimensionadas pela metodologia ótima, e a fonte de autonomia no fornecimento da potência requerida pelos veículos. Uma estratégia de gerenciamento é fundamentada em regras e a outra é fundamentada em otimização não Linear. A primeira estratégia foi aplicada para dez repetições de cada ciclo de condução, considerados no dimensionamento da ESS, e apresentou resultados satisfatórios quanto aos limites de operação dos supercapacitores e das baterias. A segunda estratégia de gerenciamento foi aplicada a determinados períodos dos ciclos de condução, nos quais, em relação à estratégia em regras, observou-se a atuação da fonte de autonomia. Os resultados mostraram que é possível obter maior economia de combustível, pois a fonte de autonomia permaneceu desativada com o emprego da estratégia de gerenciamento ótima. As duas estratégias de gerenciamento foram aplicadas aos três tipos de veículos Abstract: The energy-storage system (ESS) of electric vehicles with batteries and/or ultracapacitors can add high cost or high mass to the vehicle if the number of modules of these sources is not appropriate. Two sizing methodologies applied to the ESS are proposed in this Thesis. These methodologies aim ESSs configurations of lowest mass. The obtained configurations must be able to supply power when the electric vehicle is driven in a certain profile of high value of power required. ESSs with different types of batteries and ultracapacitors are studied to achieve a broad range of choices of configurations in relation to weight and cost. Besides an ESS unity the electric vehicle has an autonomy source that can be a fuel cell or a generator/internal combustion engine unity. The first sizing methodology investigates different ESSs configurations for a Sport Utility Vehicle type. This methodology is based on Ragone curves of the sources from which the specific power and specific energy coefficients are obtained. The ESS of lowest mass is found by using these coefficients and the power required that must be constant. Among the ESSs configurations analyzed the results showed that the ESS of lowest mass is formed only by ultracapacitors modules of 165 F. The second methodology investigates configurations of hybrid ESSs for three vehicle models: one Sport Utility Vehicle, one minibus and one urban transit bus. This study aims to show the viability of using the methodology in vehicles with different physical characteristics. This methodology is highlighted by the use of nonlinear optimization to solve the ESS sizing problem whose objective function is the lowest mass of ESS. The innovative aspect of this methodology is the use of optimization to solve the ESS sizing problem applied to the power envelope of the driving cycle profiles. The envelope is resulting of the superposition of the power profiles related to the driving cycles in which the vehicle is driven. The purpose of using the envelope of the power profiles is to comprise different situations, in any driving cycles, in which the vehicle can be driven. The methodology is applied to certain periods of the envelope with high value of power required. Two power management strategies are proposed to manage the ESSs, sized by the optimum methodology, and the autonomy sources to supply continuously the power required by the vehicle. One power management strategy is based on rules and the other one is also based on nonlinear optimization technique. The first one was applied to ten repetitions of each driving cycle and presented good results related to batteries and ultracapacitors operational limits. The second one was applied to certain periods of the driving cycles in which the autonomy source provides nominal power related to the strategy based on rules. The results of the optimum power management strategy showed that it is possible to obtain improved fuel economy, since the autonomy source remained turned off. Both strategies were applied to the three vehicle models Doutorado Automação Doutora em Engenharia Elétric

The contribution of town functions to the development of rural areas: empirical analyses for Ethiopia

Scipedia content — Tue, 26 Jan 2021 15:44:15 +0100

Rural areas in many developing countries often lack infrastructure and institutions. However, rural towns and towns possess some of the major services that rural and town households can use to advance their economic activities. The study of the contribution that towns and their functions make to different economic activities is still in development. The thesis sought to add to the literature by conceptually discussing the role of town functions and empirically examining the influence on income, employment opportunities, rural household crop marketing and fertilizer application. For these purposes, data from households in four major regional states of Ethiopia are used. Results show that shorter distances to roads, transport services and telephone centers, and connection to electricity and tap water are likely to increase income and non-farm wage employment. We find also that proximity to roads and markets and strong network connections are associated with improved input-output exchange among rural household

Requirements for a Nationwide Intermodal Trip Planner in the US

Scipedia content — Tue, 26 Jan 2021 15:39:19 +0100

Presently, the United States has yet to achieve the 1991 Intermodal Surface Transportation Efficiency Actâ s (ISTEA) goal of creating a seamless intermodal transportation system. In addition to the dearth of connections, the nationâ s poor transportation information systems limit intercity intermodal transportation. Travelers lack awareness of available transportation options and face too many separate portals for trip planning that both consume time and present inadequate information. This paper posits that the creation of an efficient and extensive web-based door-to-door intermodal trip planner can solve these problems. The proposed system will present travelers with a single portal to meet all their trip planning needs. Upon selecting specific trips, travelers can then decide to be directed to operators to make a purchase. The system will include operators from the major modal groups including intercity buses, intercity rail, commuter rail, transit, and airlines. It will also include taxis due to the disjointed nature of the US public transportation system and the need to connect users who are far from stations. The requirements to create this trip planner are explored, including the support systems, potential legal issues, and suitable entities for administration and management. A survey of 39 transportation system users revealed the existence of redundant and inadequate trip planners and that the lack of sufficient information on public transportation options is driving travelers to private vehicles for shorter distances even for those who prefer public means of transportation. Analysis of the costs and benefits of implementing the proposed system is drawn from interviews with key personnel within the transportation industry, and a review of nationwide trip planners in European countries. Finally, a roadmap is presented on how best to implement the system with inputs from both the public and private sector. Recommendations include the establishment of an industry-wide data standard, a national interagency database, and a cooperative structure that entices major players within each mode to participate in the system. Also suggested are incentives from the DOT and interested private sector members to encourage more operators to participate in the system. Master of Science

A time-space constrained approach for modeling travel and activity patterns

Scipedia content — Tue, 26 Jan 2021 15:33:09 +0100

Gegenstand der Arbeit ist die Entwicklung eines tour-basierten Verkehrsnachfragemodells zur Abbildung von Aktivitätenketten unter Berücksichtigung von raum-zeitlichen constraints. Den theoretischen Hintergrund bildet ein hierarchisch organisierter Entscheidungsprozess, um die theoretisch möglichen Entscheidungskombinationen zu reduzieren und damit eine wahrscheinlichkeitsbasierte Berechnung zu ermöglichen. Als Beispieltour dient die Aktivitätenkette ‚Wohnen-Arbeit-Sekundäraktivität-Wohnen’, auf deren Basis auch die statistischen Analysen der Mobilitätsbefragung Santiagos durchgeführt werden. Unter Verwendung eines GIS werden so genannte ‚Suchräume’ (Aktionsräume in denen Sekundäraktivitäten durchgeführt werden) ermittelt. Ein Ergebnis der Datenanalyse sind Grenzwerte der maximalen täglichen Reisezeit für eine Reihe von Modus-Kombinationen. Die Zeitfenster von Startzeiten und Aktivitätendauer werden in Abhängigkeit sozioökonomischer Gruppen ermittelt. Die Bestimmung der Suchräume erfolgt in Abhängigkeit von Arbeitsdauer sowie Distanz zwischen Wohn- und Arbeitsort. Beide Kriterien erwiesen sich in der Analyse als statistisch signifikant. Der Vergleich zwischen Modell und Empirie (Santiagos Mobilitätsbefragung) deutet darauf hin, dass die Suchräume geeignet sind und die Mehrheit der beobachteten Zielwahlentscheidungen beinhalten. Zur Berechnung der Wahrscheinlichkeitspfade (unter Verwendung der Programmsyntax von SPSS) wird ein im Umfang auf sieben Ziele reduziertes Alternativenset pro Wohn- und Arbeitsstandort bestimmt. Dabei werden Erreichbarkeit und Attraktivität der Ziele innerhalb des Suchraumes berücksichtigt. Die erzielten Ergebnisse stützen das Argument, dass die raum-zeitlichen constraints (tägliche Reisezeit, Suchräume) eine effektive Reduktion der kombinatorischen Vielfalt zulassen. Die Erfahrungen aus der Berechnung der Beispieltour eignen sich zum Übertrag auf weitere Tour-Typen, um eine Modellierung der städtischen Gesamtverkehrsnachfrage zu ermöglichen. In this thesis we develop a tour-based approach for modeling activity and travel pattern considering time-space constraints. A hierarchical structure of choice-making builds theoretical background for the model and is based on a set of axiomatic rules. Our central argument is that the time-space constraints can be used for reducing the number of choices and, respectively, control the combinatorics associated with the probabilistic approach. The empirical analysis of our use case, a tour of type ‘Home-Work-SecondaryActivity-Home’, is based on Santiago’s travel survey. In addition, we apply GIS to estimate the so-called search spaces (potential areas where secondary activities are realized) and justify their sizes with the empirical findings. From the data analysis we identify thresholds for the tour-based maximum daily travel times considering a set of mode combinations. We define regimes of starting times and duration of activities depending on socio-economic user groups. The estimation of search spaces is realized considering the time spent at work as well as the distance between the home and work locations. Both criteria were found to be statistically significant. The comparison of modeled results with survey observations allowed concluding that the search spaces are realistic since they capture most of the observed trip destinations. For the estimation of spatial path flows of activities and trips (using SPSS programming language), we define a final choice set of no more than seven alternatives per primary location considering zone-based accessibility and land-use attractiveness. The obtained results support the argument that time-space constraints (daily travel time, search spaces) allow an effective control of combinatorial complexity. Basing on the experience obtained in process of modeling the exemplary tour, the approach can be applied to further tour types offering the possibility to estimate the entire transport demand of Santiago city.

Kentiçi Otoyollarda Model Tabanlı Öngörüye Dayalı Değişken Hız Sınırlaması İle Akım Denetimi

Scipedia content — Tue, 26 Jan 2021 14:29:20 +0100

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012

Passive safety in electric vehicles from a structural perspective

Scipedia content — Tue, 26 Jan 2021 14:20:23 +0100

PFC del programa Erasmus EPS

Analysis of critical systems through rigorous, reproducible and comparable experimental assessment

Scipedia content — Tue, 26 Jan 2021 14:19:22 +0100

MULTIBODY APPROACH FOR RAILWAY DYNAMIC ANALYSIS

Scipedia content — Tue, 26 Jan 2021 14:14:43 +0100

En este trabajo se ha llevado a cabo el desarrollo de una herramienta computacional para la simulación dinámica de vehículos ferroviarios. El modelo está basado en técnicas multicuerpo debidas a Shabana. Con respecto a otras metodologías existentes, la propuesta hace uso de un conjunto de sistemas de referencia que permite el empleo de coordenadas independientes sin la posibilidad de configuraciones singulares debidas a grandes giros. El conjunto de sistemas de referencia sirve de base para formular de manera precisa el problema de contacto rueda-carril. El programa está diseñado para considerar de forma flexible distintas configuraciones de vehículo así como diversas geometrías de trazado. La estructura del programa está abierta a cambios orientados a la mejora del modelo de contacto rueda-carril o a la implementación de la dinámica estructural de la vía. Se ha implementado un modelo eficiente que permite detectar con precisión las coordenadas de los puntos en contacto localizados en la interfase entre la rueda y el carril. La herramienta de simulación desarrollada en esta tesis se ha aplicado para diferentes casos-estudio con el objetivo de validar la idoneidad de la metodología propuesta en el análisis del sistema ferroviario. Se ha realizado una comparación entre los resultados obtenidos por la herramienta de simulación presentada y los resultados ofrecidos por varios programas comerciales de simulación dinámica en el análisis del vehículo de Manchester Benchmark. Además, la herramienta se ha empleado para desarrollar un análisis dinámico del vehículo de la locomotora TGV y los resultados obtenidos se han comparado con los ofrecidos por el programa comercial SIMPACK para el mismos modelo de vehículo, bajo las mismas condiciones de operación. Finalmente, sobre la base de la calidad de los resultados, se puede concluir que la herramienta de simulación es fiable y eficiente para emplearse en el análisis dinámico de los diferentes sistemas ferroviarios.

İstanbul Avcılar – Söğütlüçeşme Metrobüs Sisteminin Bileşenlerinin Değerlendirmesi Ve Dünyadaki Metrobüs Sistemleri İle Karşılaştırılması

Scipedia content — Tue, 26 Jan 2021 14:08:20 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012

The aggregate effect of turns on urban traffic networks

Scipedia content — Tue, 26 Jan 2021 13:57:20 +0100

This dissertation furthers the understanding of macroscopic traffic behavior on urban networks. In particular, it focuses on the aggregate effect of turning maneuvers in networks with multiple routes. The presence of turning between different routes on a network is found to have two effects: 1) it causes chaotic and inefficient behavior, especially when the network is congested; and, 2) it may reduce maximum vehicle flows across the network. Fortunately, this work finds that designing networks that are redundant (i.e., have multiple unique routes between all origin-destination pairs), helping drivers avoid locally congested regions and limiting the rate at which vehicles are allowed to enter the network can help mitigate the first effect, and this allows the network to operate more efficiently. It is also found that the second effect may not always be harmful---lower network flows do not necessarily result in decreased network efficiency if the lower flows are accompanied by more direct routing between origins and destinations. In fact, two-way networks, which accommodate conflicting left-turns and result in lower maximum vehicle flows than one-way networks, are found to serve trips at a higher rate because drivers travel shorter distances on average. Thus, in many cities, maximum network efficiency can be improved by converting one-way streets to two-way operation.

The possibility and feasibility of installing a bicycle sharing system in Tallinn

Scipedia content — Tue, 26 Jan 2021 13:52:47 +0100

The main objective of this thesis is to establish a bicycle system in Tallinn. It will explain the whole process for establishing the system. The first part consists in analyze the different bike sharing systems in Europe and with the obtained data it is decided which si the most suitable operating system for Tallinn. This analysis is complemented with calculations and graphs that are going to help us to determinate which parameters have to has the city of Tallinn for has succeed in the installation. The second part is based on the location criteria for the stations of the system. Using location models, programming and solving it all an optimal solution will be found.

Factors influencing a building-material company brand

Scipedia content — Tue, 26 Jan 2021 13:44:37 +0100

A brand represents the essence of the value proposition an organisation extends to the market. It is crucial that brands are nurtured with the goal of trying to establish the brand in a top-of-mind awareness position among consumers. By means of a qualitative case study employing 25 interviews which were analysed by using Grounded Theory coding techniques, the most pertinent factors influencing the Corobrik brand were identified. The greatest challenge facing Corobrik is the growing residential sector. The study highlights how Corobrik has grappled and come to terms with the changing nature of its market, and how it has combined all functional areas, from production to distribution, marketing and finance, in promoting its brand.

PRESTK : situation-aware presentation of messages and infotainment content for drivers

Scipedia content — Tue, 26 Jan 2021 13:28:33 +0100

The amount of in-car information systems has dramatically increased over the last few years. These potentially mutually independent information systems presenting information to the driver increase the risk of driver distraction. In a first step, orchestrating these information systems using techniques from scheduling and presentation planning avoid conflicts when competing for scarce resources such as screen space. In a second step, the cognitive capacity of the driver as another scarce resource has to be considered. For the first step, an algorithm fulfilling the requirements of this situation is presented and evaluated. For the second step, I define the concept of System Situation Awareness (SSA) as an extension of Endsley’s Situation Awareness (SA) model. I claim that not only the driver needs to know what is happening in his environment, but also the system, e.g., the car. In order to achieve SSA, two paths of research have to be followed: (1) Assessment of cognitive load of the driver in an unobtrusive way. I propose to estimate this value using a model based on environmental data. (2) Developing model of cognitive complexity induced by messages presented by the system. Three experiments support the claims I make in my conceptual contribution to this field. A prototypical implementation of the situation-aware presentation management toolkit PRESTK is presented and shown in two demonstrators. In den letzten Jahren hat die Menge der informationsanzeigenden Systeme im Auto drastisch zugenommen. Da sie potenziell unabhängig voneinander ablaufen, erhöhen sie die Gefahr, die Aufmerksamkeit des Fahrers abzulenken. Konflikte entstehen, wenn zwei oder mehr Systeme zeitgleich auf limitierte Ressourcen wie z. B. den Bildschirmplatz zugreifen. Ein erster Schritt, diese Konflikte zu vermeiden, ist die Orchestrierung dieser Systeme mittels Techniken aus dem Bereich Scheduling und Präsentationsplanung. In einem zweiten Schritt sollte die kognitive Kapazität des Fahrers als ebenfalls limitierte Ressource berücksichtigt werden. Der Algorithmus, den ich zu Schritt 1 vorstelle und evaluiere, erfüllt alle diese Anforderungen. Zu Schritt 2 definiere ich das Konzept System Situation Awareness (SSA), basierend auf Endsley’s Konzept der Situation Awareness (SA). Dadurch wird erreicht, dass nicht nur der Fahrer sich seiner Umgebung bewusst ist, sondern auch das System (d.h. das Auto). Zu diesem Zweck m¨ussen zwei Bereiche untersucht werden: (1) Die kognitive Belastbarkeit des Fahrers unaufdringlich ermitteln. Dazu schlage ich ein Modell vor, das auf Umgebungsinformationen basiert. (2) Ein weiteres Modell soll die Komplexität der präsentierten Informationen bestimmen. Drei Experimente stützen die Behauptungen in meinem konzeptuellen Beitrag. Ein Prototyp des situationsbewussten Präsentationsmanagement-Toolkits PresTK wird vorgestellt und in zwei Demonstratoren gezeigt.

The Taxi: Friend or Foe? Understanding Planners' Perceptions of the Taxi Industry

Scipedia content — Tue, 26 Jan 2021 13:14:50 +0100

The story of the taxi in the system of urban mobility is a story of so much unmet potential: There are many opportunities for taxis to play a much larger role in urban mobility, and yet, transportation planners have by and large overlooked these opportunities in practice. In this thesis, I examine whether perceptions--internalized and likely unexamined assumptions about the taxi, largely false--are to blame. I highlight seven commonly held misconceptions about the taxi, and survey a sample of 133 transportation planners to gauge the extent to which these misconceptions are held to be true. The results of the survey at least partially confirm the hypothesis. Taxis appear to be viewed as neither friend nor foe: an isolated industry divorced from transportation concerns, rather than a true partner in a comprehensive system of urban mobility.

Development of Protective Coatings for Co-Sequestration Processes and Pipelines

Scipedia content — Mon, 25 Jan 2021 20:00:49 +0100

The program, entitled âDevelopment of Protective Coatings for Co-Sequestration Processes and Pipelinesâ, examined the sensitivity of existing coating systems to supercritical carbon dioxide (SCCO2) exposure and developed new coating system to protect pipelines from their corrosion under SCCO2 exposure. A literature review was also conducted regarding pipeline corrosion sensors to monitor pipes used in handling co-sequestration fluids. Research was to ensure safety and reliability for a pipeline involving transport of SCCO2 from the power plant to the sequestration site to mitigate the greenhouse gas effect. Results showed that one commercial coating and one designed formulation can both be supplied as potential candidates for internal pipeline coating to transport SCCO2.

Minimizing Truck-Car Conflicts on Highways, Phase I

Scipedia content — Mon, 25 Jan 2021 19:52:06 +0100

Trucks represent the predominant form of domestic freight movement. Due to the substantial increase in freight truck traffic on the nation's highways, its influence on traffic flow performance, safety, and quality of travel experience is garnering increased attention. Several existing studies have addressed the impacts of trucks on highway traffic flow conditions and crashes. This research models the behavior of non-truck drivers vis-a-vis their interactions with trucks by associating a "discomfort level" with every non-truck driver. This discomfort of non-truck drivers in the vicinity of trucks is assumed to be affected by situational factors such as time-of-day, weather, and ambient traffic congestion. Stated preference surveys of non-truck drivers are used to elicit the factors that influence their behavior when interacting with trucks on highways. A fuzzy logic model using if-then rules is developed to characterize non-truck driver behavior near trucks. It is used to determine the non-truck driver discomfort level, and is constructed using survey data and insights from the preliminary analysis performed using a binary discrete choice model. The discomfort level is used in conjunction with a traditional car-following traffic flow model to generate a truck-following model. Similarly, a modified lane-changing model is constructed to account for car-truck interactions. This redresses a key methodological gap in the literature and provides a capability to analyze alternative strategies to reduce car-truck interactions. An agent-based freeway segment microscopic traffic simulator is constructed using the car-following and lane-changing logics embedded in the FRESIM microscopic simulator, and the truck-following and modified lane-changing models developed in this research. Simulation experiments using data from the Borman expressway (I-80/94) in northwest Indiana are used to analyze model sensitivity to the various parameters and evaluate the effectiveness of alternative mitigation strategies.

Identifikacija voznikov v prometnih nesrečah in določanje pozicij udeležencev v vozilu po prstnih sledeh

Scipedia content — Mon, 25 Jan 2021 19:38:36 +0100

The following paper aims to illustrate certain investigative activities in the forensic analysis and examination of the scene of traffic accidents. When a traffic accident occurs, the scene must be secured as soon as possible to enable professional and proper forensic investigation. Failure to secure the accident scene might result in losing or contaminating the traces, which makes it more difficult to prove or explain trace evidence in further procedure or even makes such evidence inadmissible. The topic is discussed from the viewpoint of crime scene examination, since analysing and investigating traffic accidents requires a great deal of expertise and attention of the investigators. Complex traffic accidents include feigned accidents, hit-and-run accidents as well as accidents in which the driver and passengers, dead or alive, need to be identified. In identifying the passengers, standard criminal investigation methods as well as police forensic and forensic medicine methods are followed. Such methods include confirming the identities with identity documents, other documents and vehicle ownership, fingerprints, biological traces, fibre traces, contact traces, traces of physical injuries on the driver and passengers, etc. According to the results obtained in fingerprint detection on human skin surfaces, this method can also be applied in confirming physical contact between the driver and the passengers in the accident, e.g. in the event of moving the victims and changing the scene of the accident. Namen prispevka je pojasniti določena preiskovalna dejanja pri analizi t.j. pri kriminalistično tehničnem oz. forenzičnem ogledu kraja prometne nesreče. V primeru prometne nesreče je treba za strokovno in pravilno forenzično preiskovanje čim hitreje zavarovati kraj. Če se kraj dejanja ne zavaruje, se sledi izgube ali kontaminirajo, kar vodi do težjega dokazovanja ali pojasnjevanja dokazov v postopku ali celo do njihove popolne nezmožnosti. Vidik obravnavanja je usmerjen v izhodišča ogledne dejavnosti, saj analiza prometnih nesreč v cestnem prometu in preiskovanje zahtevajo od preiskovalcev veliko znanja in pozornosti. Zelo zahtevni so primeri fingiranih prometnih nesreč, prometnih nesreč ko vozniki ali udeleženci zapustijo kraj dogodka ter nesreče, kjer je treba ugotoviti identiteto voznika in udeležencev, živih ali mrtvih. Ugotavljanje istovetnosti udeležencev poteka po ustaljenih kriminalističnih oz. forenzičnih ter sodnomedicinskih metodah. Mednje se prišteva tudi potrditev identitete po osebnih dokumentih, dokumentih in lastništvu vozil, prstnih sledeh, bioloških sledeh, sledeh vlaken in kontaktnih sledeh, sledeh telesnih poškodb voznika in udeležencev ip. Rezultati preiskave detektiranja prstnih sledi na površini človeške kože so pokazali, da je tudi tovrstno metodo možno uporabiti pri potrditvi fizičnega kontakta voznika z udeleženci v prometni nesreči, npr. pri premikanju žrtev in fingiranju kraja dejanja.

Pipeline Transport of Crude Petroleum, Operation

Scipedia content — Mon, 25 Jan 2021 19:21:41 +0100

Methodology, evaluation, simulation and assessment for the analysis of the deployment of DSB and EEIC systems of the FREILOT project Contribution of LET

Scipedia content — Mon, 25 Jan 2021 18:54:17 +0100

This report contains the main contribution of CNRS-LET to the FREILOT project. It is organized in 4 main parts: the first presents the methodological contributions to the evaluation of ICT systems, the second the methodological contribution to the delpoyment assessment and analysis. The other two concern mainly the evaluation results produced by LET and the Cost Benefit Analyses and results made also by LET.

Russian Economic Report, No. 24, March 2011 : Sustaining Reforms under the Oil Windfall

Scipedia content — Mon, 25 Jan 2021 18:51:35 +0100

Despite the recent slowdown, the underlying growth of the global economy remains solid. After a 4 percent growth in 2010, Russia's real output is expected to grow 4.4 percent in 2011, increasingly driven by domestic demand. Russia's households have absorbed the food price shock thanks to a combination of higher wages and pensions, and resort to private and public safety nets. The country emerged from the global recession with lower unemployment and poverty than feared. But global risks and uncertainties increased with the new oil shock. Although the short-term impact will be positive for Russia's export and fiscal revenues, there is no room for complacency. Macroeconomic policy should focus on the short-term objective of controlling inflation and medium-term fiscal adjustment towards long-term, sustainable level of non-oil fiscal deficit. Improving the efficiency of public expenditure to create fiscal space for productive infrastructure and strengthening the investment climate for the private sector remain among key long-term challenges. The ongoing rethinking of the government's long-term strategy and a period of high oil revenues provide an opportunity to focus on these long-term issues more forcefully than during the global crisis.

Natural Gas, Pipeline, Transport

Scipedia content — Mon, 25 Jan 2021 18:49:21 +0100

Procesni način obvladovanja stroškov logistične dejavnosti v proizvodnem podjetju

Scipedia content — Mon, 25 Jan 2021 18:33:46 +0100

Both the transparent reporting of logistics costs and the related accounting of their cost drivers present a significant factor for the successful management of material flows and the related logistics activities in production companies. These costs, which are mainly reported as part of overhead (indirect) costs in such companies, usually remain hidden or are not explicitly visible when the traditional method of accounting is applied. The aim of this research is to create a model of activity-based accounting of logistics costs in a production company, and to test its efficiency in the disclosure of logistics costs compared with traditional cost accounting. The application of the model in a production company shows that an activity based approach discloses as much as 108% more logistics costs at the level of a group of products than the traditional cost accounting approach. Further, detailed information on logistics costs obtained in this way enables their more efficient management. Pomemben pogoj za uspešno obvladovanje materialnih tokov in z njimi povezanih logističnih dejavnosti v proizvodnih podjetjih predstavlja kar se da transparentno izkazovanje in z njihovimi povzročitelji smiselno povezano spremljanje stroškov logističnih dejavnosti. Ti so pretežno sestavina splošnih stroškov takih podjetij in pri tradicionalnem računovodenju stroškov ostajajo v veliki meri skriti oziroma ne eksplicitno vidni. Namen raziskave je oblikovanje modela procesnega spremljanja stroškov logistike v proizvodnem podjetju ter preizkus njegove učinkovitosti pri razkrivanju stroškov logistikev primerjavi s tradicionalnim računovodenjem stroškov. Aplikacija modela na primeru proizvodnega podjetja dokazuje, da ta razkrije na ravni skupine proizvodov kar 108 % več stroškov logistike kot tradicionalni model spremljanja stroškov v podjetju, z njim pridobljene razčlenjene informacije o stroških logistike pa lahko omogočajo tudi njihovo boljše obvladovanje.

Illumina GA IIx& HiSeq 2000 Production Sequenccing and QC Analysis Pipelines at the DOE Joint Genome Institute

Scipedia content — Mon, 25 Jan 2021 18:31:00 +0100

The U.S. Department of Energy (DOE) Joint Genome Institute's (JGI) Production Sequencing group is committed to the generation of high-quality genomic DNA sequence to support the mission areas of renewable energy generation, global carbon management, and environmental characterization and clean-up. Within the JGI's Production Sequencing group, a robust Illumina Genome Analyzer and HiSeq pipeline has been established. Optimization of the sesequencer pipelines has been ongoing with the aim of continual process improvement of the laboratory workflow, reducing operational costs and project cycle times to increases ample throughput, and improving the overall quality of the sequence generated. A sequence QC analysis pipeline has been implemented to automatically generate read and assembly level quality metrics. The foremost of these optimization projects, along with sequencing and operational strategies, throughput numbers, and sequencing quality results will be presented.

Exploration of Transit’s Sustainability Competitiveness

Scipedia content — Mon, 25 Jan 2021 18:29:36 +0100

With growing interest in climate change and greater anticipation of energy cost increases, being sustainable has implications for the financial efficiency of transit agencies and on the image and appeal that transit has to offer current and prospective customers. Being more resource efficient can help the agency financially, increase its ridership and public support, and increase its contribution to broader national goals of moving toward a more sustainable transportation system. Collectively, these considerations provide strong motivation for transit to strive toward greater sustainability and articulate its contributions toward a more sustainable transportation system to the public and policy makers. Towards that end, this research initiative explores select aspects of public transit’s sustainability. The data regarding the fuel efficiency of public transit bus travel has been explored in detail, with results that may be surprising to many. First, the message from the data is confusing, as different sources show significantly different results. Closer scrutiny suggests that the actual performance of transit bus may be poorer than often reported and far poorer than commonly perceived. Based on national averages, transit bus use is not a more fuel efficient way to travel than auto, on average. (This does not apply to the marginal user who chooses to occupy available transit capacity.) When adjusted for context differences, bus and personal light vehicle modes appear to be virtually identical in terms of BTUs per passenger mile. Finally, transit may contribute to energy efficiency if, working with effective urban design, it attracts people to live in well-planned communities and to adopt travel habits that are less reliant on private vehicles. Transportation planning professionals are still learning how urban design can contribute to effective urban transit and greater overall energy efficiency.

Review of Urban Air Quality in Sub-Saharan Africa Region : Air Quality Profile of SSA Countries

Scipedia content — Mon, 25 Jan 2021 18:26:32 +0100

In Africa, urban outdoor air pollution is responsible for an estimated 49,000 premature deaths annually with indoor use of solid fuels being responsible for eight times this value, the main burden being borne by Sub Saharan African countries. Air pollution, outdoor and indoor, affects the health and life chances of millions of people in Sub Saharan Africa (SSA)every day. There is a link between air pollution and poverty since poor people are exposed to higher concentrations of air pollutants and tend to suffer disproportionately from the effects of deteriorating air quality (AQ). Children in cities exposed to high concentrations of air pollutants will more often develop respiratory ailments which prevent them from developing and learning well. As a consequence they will suffer in adult life from low levels of qualifications and skills. The implication of poorly educated children is not only a reduction of quality of their lives but also an obstacle for the economic development of a country as a whole. Rapid urbanization means increase in motorization and economic activity which in turn leads to increased air pollution if countermeasures are not taken. In view these linkages addressing urban AQ in SSA is particularly important. Air pollution in Sub Saharan cities appears to be on the rise with respect to many key pollutants. In some cities where monitoring has been performed levels of air pollution exceed World Health Organization recommended guidelines. The main cause of urban air pollution is the use of fossil fuels in transport, power generation, industry and domestic sectors. In addition, the burning of firewood, agricultural and animal waste also contributes to pollution levels. Pollutant emissions have direct and indirect effects with a wide range of impacts on human health, ecosystems, agriculture and materials. There is a growing need to determine the state of urban AQ and the challenges posed to solve it and identify the most effective measures to protect human health and the environment. Learning from experience and successes in urban AQ management (AQM) from other countries can assists in the formulation and implementation of strategies to achieve better AQ in Sub Saharan Africa. This report compiles the information provided by the 25countries in a harmonized way and gives an in-depth review of AQ in SSA with AQ profile of each country, presenting the country's main current urban AQ issues, emissions standards, ongoing projects, lessons learned from good/bad practices. It was attempted to compile this information also for additional SSA countries from available publications and internet sources.

The European road pricing game: how to enforce optimal pricing in high-transit countries under asymmetric information

Scipedia content — Mon, 25 Jan 2021 18:22:48 +0100

federal government tries to force local governments to implement welfare optimal tolling and investment. Welfare optimal tolling requires charging for marginal external costs. Local governments have an incentive to charge more than the marginal social cost whenever there is transit traffic. We analyse the pricing and investment issue in an asymmetric information setting where the local governments have better information than the federal government. The case of air pollution and of congestion are discussed. ispartof: CES - Discussion paper series DPS11.19 pages:1-33 status: published

Who Governs Rural Russia? : Preliminary Outcomes of the 2006 Decentralization Reform

Scipedia content — Mon, 25 Jan 2021 18:17:59 +0100

The objectives of the study are to: a) increase understanding of the effects and effectiveness of the implementation of the local government reform launched in 2006; and b) assess the impact of a World Bank-supported intervention that aimed to enhance effectiveness of the reforms by increasing local capacity and local participation. In line with these objectives, the study assessed the perceived effects and effectiveness of the implementation of the local government reform in selected provinces. The study also constitutes a baseline to allow for on-going assessment of progress and to inform corrective policy actions. The instruments and methods created during the study may be used in future assessments of the dynamics of local governance reform. These effects are reviewed in section two. The study also carried out a rigorous evaluation of the impact of an operational intervention carried out with World Bank support in the three regions of the study. This grant-funded project was aimed at increasing the effectiveness of participation of rural citizens in public life and increasing the capacity of local administrations to operate in the new legal and fiscal environment created by the decentralization reform. The summary of the impact evaluation can be found in section three.

Warrants for Location and Design of Local Service Roads : Final Report

Scipedia content — Mon, 25 Jan 2021 18:03:30 +0100

Aligned R&D and transport policy to meet EU GHG reduction targets: Final Report - Deliverable D7.1; GHG-TransPoRD. Reducing Greenhouse-gas Emissions of Transport Beyond 2020: Linking R&D, Transport Policies and Reduction Targets

Scipedia content — Mon, 25 Jan 2021 18:00:28 +0100

This report synthesizes the activities and the findings of the GHG-TransPoRD project. GHG-TransPoRD has developed an integrated European transport sector strategy that links R&D efforts with other transport policies and technological measures to achieve substantial greenhouse gas (GHG) emission reductions in transport that are in line with the overall GHG reduction targets of the EU, in particular verifying if the target proposed by the European Transport White Paper "Roadmap to a Single European Transport Area" (2011) could actually be met. Based on three steps: 1. quantification of GHG reduction potentials of single measures, 2. cost assessment of single measures and 3. bundling of measures into policy packages and testing these as part of scenarios with a model-based integrated assessment approach the GHG-TransPoRD project concluded that it will be feasible to achieve the GHG reduction target of -60% until 2050 compared with 1990. Road transport, and in particular car transport, has to deliver the largest absolute reductions of energy demand and GHG emissions. In parallel, the European electricity system would have to be converted into a renewable based system generating at least 80% of electricity from renewable energy sources in 2050. However, the -60% target is ambitious as most of the scenarios and policy packages tested by GHG-TransPoRD failed to deliver the required reductions. Only, scenarios combining (1) fast development of efficiency technology, (2) alternative engine technologies able to build their energy supply on renewable electricity, (3) ambitious policy-making to counterbalance rebound effects and maintain financial stability of government transport revenues, (4) ambitious regulation phasing out fossil fuel cars around 2035 together with a moderate modal-shift of 4% percentage points from road towards more energy efficient modes would enable to achieve the GHG targets. Technology scenarios either focussing on efficiency of conventional cars or on alternative technologies would deliver about -34% to 37% percentage point reductions of GHG emissions until 2050. Adding policies in the scenarios, in particular pricing policies, to foster behavioural change, would roughly add another -10% reduction. The remaining GHG reductions would need to result from adding the ambitious regulations in the scenarios.

Building the Palestinian State : Sustaining Growth, Institutions, and Service Delivery

Scipedia content — Mon, 25 Jan 2021 17:56:49 +0100

Since the last Ad Hoc Liaison Committee (AHLC) meeting, the PA has continued to strengthen its institutions, delivering public services and promoting reforms that many existing states struggle with. The quality of its public financial management (PFM) has further improved. Education and health in the West Bank and Gaza (WB&G) are highly developed, comparing favorably to the performance of countries in the region as well as globally. Ultimately, sustainable economic growth in WB&G can only be underpinned by a vibrant private sector. The latter will not rebound significantly while Israeli restrictions on access to natural resources and markets remain in place, and as long as investors are deterred by the increased cost of business associated with the closure regime. Education and health indicators for WB&G are impressive and reflect extensive coverage of the population, but a focus on improving the quality of these services remains warranted. Similarly, education investments take time to mature. While the PA is already implementing an education sector plan that highlights the importance of improving the quality of education, the relevance of graduates' skills remains an area requiring further attention. This report will therefore reflect on recent growth trends but also on the future trade regime and employability of the WB&G labor force.

The Fundamental Law of Road Congestion: Evidence from US cities

Scipedia content — Mon, 25 Jan 2021 17:54:06 +0100

We investigate the relationship between interstate highways and highway vehicle kilometers traveled (vkt) in us cities. We find that vkt increases proportionately to highways and identify three important sources for this extra vkt: an increase in driving by current residents; an increase in transportation intensive production activity; and an inflow of new residents. The provision of public transportation has no impact on vkt. We also estimate the aggregate city level demand for vkt and find it to be very elastic. We conclude that an increased provision of roads or public transit is unlikely to relieve congestion and that the current provision of roads exceeds the optimum given the absence of congestion pricing.

Do Social Connections Reduce Moral Hazard? Evidence from the New York City Taxi Industry

Scipedia content — Mon, 25 Jan 2021 17:47:39 +0100

This study investigates the role of social networks in aligning the incentives of economic agents in settings with incomplete contracts. We study the New York City taxi industry where taxis are often leased and lessee-drivers have worse driving outcomes than owner-drivers as a result of a moral hazard associated with incomplete leasing contracts. Using instrumental variables and fixed-effects analyses, we find that: (1) drivers leasing from members of their country-of-birth community exhibit significantly reduced effects of moral hazard; (2) network effects appear to operate primarily via social sanctions; and (3) network benefits can help to explain the organization of the industry in terms of which drivers and owners form business relationships.

Sudan Infrastructure : A Continental Perspective

Scipedia content — Mon, 25 Jan 2021 17:41:39 +0100

Improvements in infrastructure in all parts of Sudan in recent years have had a strong impact on per capita growth, contributing 1.7 percentage points. Consistent with trends in other countries, the information and communication (ICT) revolution that swept Africa contributed the most to Sudan. Raising the infrastructure endowment of all parts of Sudan to that of the region's best performer, Mauritius, could boosts annual growth by about 3.5 percentage points. Sudan has invested heavily in infrastructure in recent years, with some notable achievements. Power generation capacity tripled in just a few years, rising from around 800 megawatts (MW) in 2005 to 2,687MW in 2007, with a shift toward hydropower. Nevertheless, service reliability remains an issue. In ICT, Sudan has made enormous strides in liberalizing the sector and as a result has attracted significant private capital. Mobile penetration soared from less than 1 percent in 2000 to 33 percent in 2009. Recent connectivity to an undersea fiber-optic cable has led to expansions in access, improvements in quality, and reduction in prices. Looking ahead, Sudan's most pressing infrastructure challenges lie in the water and transport sectors. Sudan's infrastructure development has so far had a national focus, and there is much that remains to be done to achieve greater regional integration. While internal road corridors are developed, connectivity with neighbors is largely absent. Sudan has a natural gateway to the sea through Port Sudan but the port's performance is severely hindered by long dwell times, high costs, and capacity constraints. Looking further ahead, Sudan has the potential to be a major hydropower exporter if additional capacity could be developed and transmission links with neighboring Nile Basin countries strengthened.

Public acceptability of sustainable transport measures: A review of the literature

Scipedia content — Mon, 25 Jan 2021 17:39:38 +0100

Increasingly, the debate on transport policy involves the challenge of sustainable development. The concept of sustainable transport is derived from the general term of sustainable development. Sustainable transportation can be considered by examining the sustainability of the transport system itself, focusing on its positive and negative external effects on: the environment; public health; safety and security; land use; congestion; economic growth; and social inclusion (OECD, 2000). While traditional transport problems may be solved within the transport sector (i.e. satisfying basic needs of the movement of people and goods by the provision of large scale transport networks), solutions to sustainability problems call for an integrated approach. This approach should take into account the acceptability of sustainable transport policies that may conflict with individual short-term interests, especially when individual users are asked to significantly adapt their lifestyles and transport behaviour with impacts on their perceived quality of life (Miola, 2008). Political efforts towards the sustainability of the transport sector are in place (e.g. EC, 2011). These are, however, in the context of trends which could not be called sustainable. Currently, the main trends are related to increasing mobility demand, more cars driving more and longer distances; cheaper and cheaper travel prices allowing easy access to far away places; and infrastructures and habits adjusted to road transport (EEA, 2009). As noted above public acceptability of the measures to address these trends and achieve sustainable transport is required. The paper will identify some of the difficulties faced in achieving this acceptability. Its focus, more importantly, will be on identifying positive ways forward. In terms of the review the emphasis was on literature which considered public acceptability of (sustainable) transport measures rather than the broader literature on sustainable transport per se. The aim of the review is, purposefully, a synthesis of the literature relevant to the guiding questions set out below, rather than an in-depth systematic review: o What are the negative impacts of transport to be resolved? What are the key measures identified to reduce these impacts? o What are the key themes in terms of achieving the social acceptability of the different measures? o Where has social acceptability been achieved? What can we learn from this? The approach was innovative in that it set out to compare and draw findings from a range of transport literature examining pricing, modal shift and technological change. While caution is of course required, like is not necessarily being compared with like, this approach brought a useful and different viewpoint to the understanding of the key themes as they relate to acceptability and change. The structure of the report is as follows: o Identification of the main measures to reduce transport’s impacts o Key themes for public acceptability of the different measures o Conclusions and recommendation

Making the Traffic Operations Case for Congestion Pricing: Operational Impacts of Congestion Pricing

Scipedia content — Mon, 25 Jan 2021 17:39:14 +0100

Congestion begins when an excess of vehicles on a segment of roadway at a given time, resulting in speeds that are significantly slower than normal or 'free flow' speeds. Congestion often means stop-and-go traffic. The transition occurs when vehicle density (the number of vehicles per mile in a lane) exceeds a critical level. Once traffic enters a state of congestion, recovery or time to return to a free-flow state is lengthy; and during the recovery process, delay continues to accumulate. The breakdown in speed and flow greatly impedes the efficient operation of the freeway system, resulting in economic, mobility, environmental and safety problems. Freeways are designed to function as access-controlled highways characterized by uninterrupted traffic flow so references to freeway performance relate primarily to the quality of traffic flow or traffic conditions as experienced by users of the freeway. The maximum flow or capacity of a freeway segment is reached while traffic is moving freely. As a result, freeways are most productive when they carry capacity flows at 60 mph, whereas lower speeds impose freeway delay, resulting in bottlenecks. Bottlenecks may be caused by physical disruptions, such as a reduced number of lanes, a change in grade, or an on-ramp with a short merge lane. This type of bottleneck occurs on a predictable or 'recurrent' basis at the same time of day and same day of week. Recurrent congestion totals 45% of congestion and is primarily from bottlenecks (40%) as well as inadequate signal timing (5%). Nonrecurring bottlenecks result from crashes, work zone disruptions, adverse weather conditions, and special events that create surges in demand and that account for over 55% of experienced congestion. Figure 1.1 shows that nonrecurring congestion is composed of traffic incidents (25%), severe weather (15%), work zones, (10%), and special events (5%). Between 1995 and 2005, the average percentage change in increased peak traveler delay, based on hours spent in traffic in a year, grew by 22% as the national average of hours spent in delay grew from 36 hours to 44 hours. Peak delay per traveler grew one-third in medium-size urban areas over the 10 year period. The traffic engineering community has developed an arsenal of integrated tools to mitigate the impacts of congestion on freeway throughput and performance, including pricing of capacity to manage demand for travel. Congestion pricing is a strategy which dynamically matches demand with available capacity. A congestion price is a user fee equal to the added cost imposed on other travelers as a result of the last traveler's entry into the highway network. The concept is based on the idea that motorists should pay for the additional congestion they create when entering a congested road. The concept calls for fees to vary according to the level of congestion with the price mechanism applied to make travelers more fully aware of the congestion externality they impose on other travelers and the system itself. The operational rationales for the institution of pricing strategies are to improve the efficiency of operations in a corridor and/or to better manage congestion. To this end, the objectives of this project were to: (1) Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the study of actual projects, and (2) Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the use of modeling and other analytical methods. Specifically, the project was to identify credible analytical procedures that FHWA can use to quantify the impacts of various congestion pricing strategies on traffic flow (throughput) and congestion.

Value of Travel-Time Reliability: Commuters Route-Choice Behavior in the Twin Cities

Scipedia content — Mon, 25 Jan 2021 17:26:47 +0100

Travel-time variability is a noteworthy factor in network performance. It measures the temporal uncertainty experienced by users in their movement between any two nodes in a network. The importance of the time variance depends on the penalties incurred by the users. In road networks, travelers consider the existence of this journey uncertainty in their selection of routes. This choice process takes into account travel-time variability and other characteristics of the travelers and the road network. In this complex behavioral response, a feasible decision is spawned based on not only the amalgamation of attributes, but also on the experience travelers incurred from previous situations. Over the past several years, the analysis of these behavioral responses (travelers’ route choices) to fluctuations in travel-time variability has become a central topic in transportation research. These have generally been based on theoretical approaches built upon Wardropian equilibrium, or empirical formulations using Random Utility Theory. This report focuses on the travel behavior of commuters using Interstate 394 (I-394) and the swapping (bridge) choice behavior of commuters crossing the Mississippi River in Minneapolis. The inferences of this report are based on collected Global Positioning System (GPS) tracking data and accompanying surveys. Furthermore, it also employs two distinct approaches (estimation of Value of Reliability [VOR] and econometric modeling with travelers’ intrapersonal data) in order to analyze the behavioral responses of two distinct sets of subjects in the Minneapolis-Saint Paul (Twin Cities) area.

Thailand : Clean Energy for Green Low-Carbon Growth

Scipedia content — Mon, 25 Jan 2021 17:24:47 +0100

Thailand needs to avoid the high-carbon growth path of many developed countries and, instead, take a low-carbon growth path. A green low-carbon growth path is in Thailand's own interest as it can simultaneously tackle local environmental degradation, global climate change, and energy security challenges. It can also position Thailand as a regional leader in green, sustainable growth. Green low-carbon growth in Thailand could focus on the following four pillars: 1) maintaining rapid economic growth while adjusting the country's economic structure toward a less energy, and carbon-intensive economy; 2) achieving greater urbanization while shifting toward green livable low-carbon cities; 3) meeting the huge thirst for energy while transforming the energy sector toward one of high energy efficiency and widespread diffusion of low-carbon technologies; and 4) improving quality of life while shifting toward a resource-efficient and sustainable lifestyle.

Urban Mass Transport Infrastructure in Medium and Large Cities in Developing Countries

Scipedia content — Mon, 25 Jan 2021 17:23:06 +0100

Developed at the request of the Mexican G20 Presidency for consideration by the Finance Ministers and Central Bank Governors at the G20 Leaders' Summit in Mexico, and jointly prepared with the Asian Development Bank, this policy paper positioned green transport in the context of cities development. Urban transport determines the shape of a city and its ecological footprint. Many cities in low and middle income countries are at a crossroads. Policy decisions taken now, while car use is still relatively low and cities retain a relatively transit friendly, compact urban form, will affect how people will live in their cities for many decades into the future. A new paradigm of urban transport can be part of the solution to reversing the deteriorating situation in some cities of developing countries, and supporting others to embark on a sustainable, low carbon, green growth path: developing a city for people rather than cars, and including public and mass transport as a major component of the modal structure. Implementing such a new paradigm can be truly transformational. This joint World Bank and Asian Development Bank paper lays out six aspects, which are most difficult to align, yet, are critical to ensure the sustainability of urban transport systems, visionary leadership, integrated strategy for land use and urban transport, coordination among agencies, domestic capacity, adequate cost recovery, and private participation in the operation and construction of urban transport systems. The paper proposes a set of new initiatives for G20 leaders' consideration, including the development of an umbrella toolkit to guide policy makers in charge of urban planning to make transport decisions best suited to their local contexts.

Mozambique's Infrastructue : A Continental Perspective

Scipedia content — Mon, 25 Jan 2021 17:16:10 +0100

This study is a product of the Africa Infrastructure Country Diagnostic (AICD), a project designed to expand the world's knowledge of physical infrastructure in Africa. The AICD provides a baseline against which future improvements in infrastructure services can be measured, making it possible to monitor the results achieved from donor support. It also offers a solid empirical foundation for prioritizing investments and designing policy reforms in Africa's infrastructure sectors. The AICD is based on an unprecedented effort to collect detailed economic and technical data on African infrastructure. The project has produced a series of original reports on public expenditure, spending needs, and sector performance in each of the main infrastructure sectors, including energy, information and communication technologies, irrigation, transport, and water and sanitation. This report presents the key AICD findings for Mozambique, allowing the country's infrastructure situation to be benchmarked against that of its African peers. Given that Mozambique is poor but stable country, two sets of African benchmarks will be used to evaluate its situation: those for non fragile Low Income Countries (LICs) and those for Middle-Income Countries (MICs). Detailed comparisons will also be made with immediate regional neighbors in the Economic Community of West African States (ECOWAS).

Over-the-Horizon Awareness for Advanced Driver Assistance Systems: the TrafficFilter and microSlotted 1-Persistence Flooding

Scipedia content — Mon, 25 Jan 2021 17:06:44 +0100

Vehicle-to-vehicle communications (V2V) is a promising technique for Advanced Driver Assistance Systems to increase traffic safety and efficiency. A proposed system is the Congestion Assistant, which supports drivers when approaching and driving in traffic congestion. Studies have shown great potential for such systems to reduce the impact of congestion, even at low penetration. However, these studies assumed complete and instantaneous knowledge regarding position and velocity of vehicles ahead. This paper refines and analyses the TrafficFilter, designed to supply the required information to the Congestion Assistant. Vehicles collaboratively build a so-called TrafficMap, providing over-the-horizon awareness. To this end, an improvement to the Slotted 1-Persistence Flooding called microSlotted 1-Persistence Flooding is proposed and evaluated. In a simulation study the TrafficFilter is found to be a viable system to build over-the-horizon awareness for future Advanced Driver Assistance Systems like the Congestion Assistant, without triggering the phenomenon known as Broadcast Storm.

Institutional impediments to using alternative water sources in thermoelectric power plants.

Scipedia content — Mon, 25 Jan 2021 17:03:59 +0100

Performance of Transport Corridors in Central and South Asia : Measurements 2008-2009

Scipedia content — Mon, 25 Jan 2021 17:02:29 +0100

This study is part of the ongoing dialogue on reforming trade logistics, and facilitating trade and transportation in Central and South Asian countries. It presents key findings from several rounds of first-hand observations and interviews conducted with multiple stakeholders to measure the performance of key road transport corridors across the region, including Kazakhstan, Kyrgyz Republic, Tajikistan, and to some extent, Pakistan and Afghanistan. The study identifies obstacles that hinder efficient movement of goods along transport corridors, and offers recommendations for short- and medium-term reforms for participating country governments with particular emphasis on the performance of border crossings. The overall objective of this study is to provide basic information on transport corridor performance so that national policy makers and private sectors have a basis to open discussions on how they might cooperate to facilitate international trade and transport by addressing infrastructure and operational bottlenecks in the region.

Literature review: Methods and tools for environmentally friendly product design and development : Identification of their relevance to the vehicle design context

Scipedia content — Mon, 25 Jan 2021 17:00:49 +0100

QC 20120910

Information provision by regulated public transport companies

Scipedia content — Mon, 25 Jan 2021 16:49:03 +0100

We study the interaction between pricing, frequency of service and information provision by public transport firms offering scheduled services, and we do so under various regulatory regimes. The model assumes that users can come to the bus stop or rail station at random or they can plan their trips; the fraction of users who plan their trips is endogenous and depends on the frequency of service and on the quality of information provided. Four institutional regimes are considered, reflecting various degrees of government regulation. A numerical example illustrates the theoretical results. Findings include the following. First, fare regulation induces the firm to provide less frequency and less information than is socially optimal. Second, if information and frequency did not affect the number of planning users a higher fare always induces the firm to raise both frequency and the quality of information. With endogenous planning, however, this need not be the case, as the effect of higher fares strongly depends on how frequency and information quality affect the number of planners. Third, a profit-maximizing firm offers more information than a fare-regulated firm. Fourth, if the agency regulates both the fare and the quality of information then more stringent information requirements induce the firm to reduce frequency; this strongly limits the welfare improvement of information regulation. Finally, of all institutional structures considered, socially optimal fares, frequency and quality of information stimulate passengers least to plan their trips, because the high frequency offered reduces the benefits of trip planning. (C) 2011 Elsevier Ltd. All rights reserved.

Air transport services in remote regions

Scipedia content — Mon, 25 Jan 2021 16:38:37 +0100

The need for public support. The existing programs for public support have been made with reference to the need for essential air transport services for providing local communities with lifeline transport services. However, the criteria for giving public support (via the programs in USA, Canada and Europe) allows for quite wide interpretation of the terms “remote regions” and “lifeline services”. In some places, subsidies are given to routes with quite heavy traffic where the potential for ordinary commercial services could have been offered. In other subsidy programs, air services’ role as lifeline transport can be questioned because there are modes of surface transport that probably can serve these lifeline needs. A clearer set of criteria for “remoteness” and “lifeline services” could perhaps be developed. The allocative efficiency of the services should be focused, i.e. that the level of service are aligned with market needs and regional policy objectives. There should also be a coordinated approach to the funding of services to remote regions across relevant transport modes.

Maritime Flows

Scipedia content — Mon, 25 Jan 2021 16:36:12 +0100

http://www.espon.eu/export/sites/default/Documents/Projects/AppliedResearch/TIGER/DFR/TIGER_DFR_wp15_maritimeflows.pdf; The main objective of the report is to underline the position of Europe and its hub/gateway ports in worldwide air and maritime flows. Three levels of analysis are considered: global, regional, and local, as well as relations between those scales. The global level focuses on the weight and position of Europe in global port traffic and maritime connections over time, notably looking at their changing geographic distribution and identifying which dominant port gateways have ensured Europe's maritime relations with the rest of the world. On a world level, the position of Europe will be analysed on various degrees of aggregation: as one single entity, as groups of port gateways (maritime ranges), and as individual cities (multiple or single terminals). The regional level looks at how such traffic and connections are distributed within the European territory, taking into account the previous level (world) while proposing a multi-scalar view on port gateways. We also wish understanding the mutual influence between global level and regional level since port gateways are embedded within local, regional, national, and trans-national economies and spatial systems. The local level will focus on one gateway-corridor through a case study highlighting concrete issues of regional planning and socio-economic development in relation with port and transport activities.

Natural Gas Dehydration

Scipedia content — Mon, 25 Jan 2021 16:32:42 +0100

Natural gas stream from production wells is saturated with water vapor, which may condense in pipelines, resulting in erosion and corrosion. When accumulated in the pipelines, it might form liquid plug, reducing the pipeline flow capacity. To avoid these potential problems, the gas stream needs to be dried to lower its water dew point. Mercury is present in many natural gas streams, and the levels can vary among different fields. Low levels of mercury are health hazards and will damage aluminum heat exchangers and equipment that are susceptible to corrosion attack by mercury. While this chapter addresses natural gas dehydration methods as well as the design and operational aspects of the relevant unit, the different methods and configurations of mercury removal unit are also discussed at the end.

Malaysia Economic Monitor, November 2011 : Smart Cities

Scipedia content — Mon, 25 Jan 2021 16:28:35 +0100

The Malaysian economy decelerated as solid domestic demand was not sufficient to offset a weakening external environment. Private consumption growth continued at a healthy pace. Favorable rubber and palm oil prices drove up incomes of smallholders while continued employment and wage growth supported urban incomes. In contrast, fixed investment was more volatile, with private investment showing signs of picking up while public investments lagged. Malaysia's overall balance of payments recorded a larger surplus in the first half of the year reflecting a widening current account surplus and substantial net financial inflows. Malaysia's open economy is expected to slow further in the remainder of 2011 and into early 2012 mainly due to the deterioration in the outlook for external demand. Cities are central to Malaysia's aspiration to become a high-income economy. Smart cities are skilled and innovative. They play a crucial role in catalyzing economic growth by generating productivity gains through agglomeration economies. Smart cities are green and sustainable. They ensure a high quality of life to all citizens and the sustainability of economic gains. Finally, smart cities are resilient.

Political Economy in Practice : Lessons from the Field

Scipedia content — Mon, 25 Jan 2021 14:54:03 +0100

This note synthesizes the experience of three political economy case studies: the water sector in West Bank and Gaza, the bus sector in Dhaka, Bangladesh, and the port sector in Chittagong, Bangladesh. The objective is to describe: the process of conducting these types of studies, and how recommendations which have a higher chance of feeding into reforms or operations can be developed. It is hoped that these insights will be useful for development practitioners and operational teams who are considering conducting political economy studies. It is increasingly accepted that better understanding and management of the political economy of policy reforms can help development agencies, including the World Bank, refine policy advice and operational support in partner countries. Support of reforms which are technically feasible and politically acceptable, while simultaneously promoting a poverty reduction agenda, remain a core challenge for the World Bank. It is anticipated that the additional time and effort put into political economy work will often translate into improved design and implementation of sector reforms and operations, and thus increase their effectiveness. It illustrates lessons for operational teams and development practitioners on conducting political economy work. Finally, it shows that certain obstacles need to be anticipated when translating political economy recommendations into design of operations and illustrates, through the case studies, how they can be addressed.

Best Operational and Maintenance Practices for City Bus Fleets to Maximize Fuel Economy

Scipedia content — Mon, 25 Jan 2021 14:47:16 +0100

In most large cities in developing countries, buses continue to be the public transport option of choice, carrying a large share of urban travelers. However, transit bus companies in these countries are often cash-strapped. In many cases, the operating cost per bus kilometer exceeds revenues and bus fares are often kept low irrespective of the cost of providing service. Many cities are dominated by old and fuel-intensive buses with high operating costs. Transit systems are also often plagued by overcrowded and undependable service, congested roadways and chaotic operating environments. Across the board, city officials in developing countries are under strong pressure to improve the efficiency and enhance the attractiveness of bus transportation. Fuel makes up a relatively large fraction of total bus operating costs, especially when labor costs are low, as in many developing countries. Fuel costs can be reduced by improving the driving style of bus drivers and through sound maintenance practices. A safe and economical driving style can reduce variable costs, decrease down time due to repair work and maintenance, mitigate negative environmental impacts and improve road safety. This guidance note1 provides detailed and practical recommendations on how city bus operations managers and their technical staff can plan and implement such enhancements to their fleets through Operations and Maintenance (O and M) practices without significant capital investments. By implementing such recommendations, municipal officials and bus operators can increase the efficiency and fuel economy of their bus systems and reduce their cities' energy consumption, congestion and pollution. This guidance note provides detailed and practical recommendations on how city bus operations managers and their technical staff can plan and implement such enhancements to their fleets through O and M practices without significant capital investments.

Air Traffic Control Decision Support for Integrated Community Noise Management

Scipedia content — Mon, 25 Jan 2021 12:45:37 +0100

This paper presents the concept for integrated community noise management in the form of a decision support system for air traffic c ontrollers. It should assist controllers in guiding arriving and departing traffic near airport s in a safe and efficient matter, making use of the future concept of four-dimensional traje ctory-based operations and technology currently under development. The system should be able to create conflict-free or deconflicted, individually customized and optimized t rajectories for all arrivals and departures. While doing so, the system minimizes the negative environmental effects of the flight operations and manages their geographical al location, both for individual movements and cumulative exposure. Apart from the concept itself, this paper also present results on a simplified concept that does not rely on the possib ility to exchange four-dimensional trajectories between air and ground and as such could be an attractive interim solution.