Scipedia: Documents published in 2007

A Method for Rapid Prototyping and Benchmarking of Arrival Sequencing and Scheduling Algorithms

Scipedia content — Thu, 28 Jan 2021 18:46:27 +0100

method is introduced for rapid prototyping and benchmarking of arrival sequencing and scheduling algorithms for air traffic management . The method has three main components: 1) algorithm models 2) rec orded air traffic simulation data, and 3) a free software library that interface s the algorithm models with the simulation output database. By accessing simulation data via a relational database, t he method makes it possible to quickly implement prototype algorithms and then to evaluate them without a direct interface to the airspace simulator code . To illustrate this method , a basic first -come, first serve d arrival sequencing and scheduling algorithm was studied . Results are offered as benchmarks for com pari son with future arrival sequencing and scheduling algorithms.

Parametric Timing Analysis for Complex Architectures

Scipedia content — Thu, 28 Jan 2021 18:37:04 +0100

Hard real-time systems have stringent timing constraints expressed in units of time. To ensure that a task finishes within its time-frame, the designer of sucha system must be able to derive upper bounds on the task's worst-case execution time (WCET). To compute such upper bounds, timing analyses are used. These analyses require that information such as bounds on the maximum numbers of loop iterations are known statically, i.e. during design time. Parametric timing analysis softens these requirements: it yields symbolic formulas instead of single numeric values representing the upper bound on the task's execution time. In this paper, we present a new parametric timing analysis that is able to derive safe and precise results. Our method determines what the parameters ofthe program are, constructs parametric loop bounds, takes processor behavior into account and attains a formula automatically. In the end, we present tests to show that the precision and runtime of our analysis are very close to those of numeric timing analysis.

Automated Ensemble Extraction and Analysis of Acoustic Data Streams

Scipedia content — Thu, 28 Jan 2021 18:21:18 +0100

This paper addresses the design and use of distributed pipelines for automated processing of sensor data streams. In particular, we focus on the detection and extraction of meaningful sequences, called ensembles, from acoustic data streamed from natural areas. Our goal is automated detection and identification of various species of birds. Although this target application is relatively specific, the process employed is general and can be extended to other problem domains such as security systems and military reconnaissance.

Travel time cost functions for urban roads: a case study in Italy

Scipedia content — Thu, 28 Jan 2021 18:14:36 +0100

This paper describes how cost functions are commonly used in traffic assignment in order to account for the effects of congestion on road link performances. Despite their influence on assignment results, not many effective functions are available for urban roads. Indeed, the effects of congestion on the travel time required to cross an urban link have often been considered negligible in comparison with those on delays at intersections. Nonetheless, traffic flow disturbances like side-parking can appreciably affect link travel time with the rise in congestion, especially in the roads of ancient centers in historical cities. Hence this paper presents a travel time function for urban road links that includes the effect of side-parking, secondary streets and road winding on the worsening of performance due to congestion. Model parameter identification was based both on empirical and experimental data, the latter having been obtained by means of a calibrated micro-simulation model. Cross-validation results do not exclude the possibility of applying the proposed function to different urban areas.

Decision Making on Train Movement Sequense for Co - Modal Transport Logistic Systems

Scipedia content — Thu, 28 Jan 2021 18:11:05 +0100

Patreiz transporta sistēmu darbība nenotiek saskaņoti, nav definēti kritēriji un saskaņoti dažādu transportu veidu maršruti (īpaši tas ir aktuāli lielās pilsētās ar augstu transporta kustības intensitāti). Rakstā decision making of train movement secuenses for co - modal transport logistics systems tiek analizētas šādas problēmas: maršrutu sastādīšana; kustības saraksta sastādīšana; pasažieru prioritāšu noteikšana; dzelzceļa transporta kustības saraksta integrācija pilsētas sabiedriskā transporta sistēmā. Tiek izstrādātas lēmumu pieņemšanas procedūras intelektuālo aģentu tīkliem par vilcienu kustības secību daudzmodu pārvadājumos transporta loģistikas sistēmās.

Supporting interactive graph exploration using edge plucking

Scipedia content — Thu, 28 Jan 2021 18:10:44 +0100

Excessive edge density in graphs can cause serious readability issues, which in turn can make the graphs difficult to understand or even misleading. Recently, we introduced the idea of providing tools that offer interactive edge bending as a method by which edge congestion can be disambiguated. We extend this direction, presenting a new tool, Edge Plucking, which offers new interactive methods to clarify node-edge relationships. Edge Plucking expands the number of situations in which interactive graph exploration tools can be used to address edge congestion.

Road Grade Estimation for Look-ahead Vehicle Control

Scipedia content — Thu, 28 Jan 2021 18:00:20 +0100

Look-ahead cruise controllers and other advanced driver assistance systems for heavy duty vehicles require high precision digital maps. This contribution presents a road grade estimation algorithm for creation of such maps based on Kalman filter fusion of vehicle sensor data and GPS positioning information. The algorithm uses data from multiple traversals of the same road to improve previously stored road grade estimates. Measurement data from three test vehicles and six road traversals have been used to evaluate the quality of the obtained road grade estimate compared to a known reference. The obtained final grade estimate compares favourably to one acquired from a specialized road grade measurement vehicle with a DGPS receiver and inertial measurement unit. QC 20120214

Speech understanding in open tasks

Scipedia content — Thu, 28 Jan 2021 17:32:42 +0100

The Air Traffic Information Service task is currently used by DARPA as a common evaluation task for Spoken Language Systems. This task is an example of open type tasks. Subjects are given a task and allowed to interact spontaneously with the system by voice. There is no fixed lexicon or grammar, and subjects are likely to exceed those used by any given system. In order to evaluate system performance on such tasks, a common corpus of training data has been gathered and annotated. An independent test corpus was also created in a similar fashion. This paper explains the techniques used in our system and the performance results on the standard set of tests used to evaluate systems.

How to Provide Indefinite Life for Municipal Metallic Transmission Pipelines

Scipedia content — Thu, 28 Jan 2021 17:32:19 +0100

Three current corrosion strategies used for Municipal Metallic Transmission Pipelines (MMTP) (defined as concrete pressure pipe, ductile iron pipe, or steel pipe 24” diameter and larger) as part of a comprehensive Asset Management Program are: 1. Run to Failure 2. Run to Failure and Repair as Required 3. Operate and Maintain to Provide an Indefinite Life (repair-free service life "100 years) The paper will discuss the short- and long-term impacts of each strategy and detail why the strategy of “Operating and Maintaining to Indefinite Life” provides the most reliable Municipal Metallic Transmission Pipelines with the fewest repairs at the lowest total cost of operation to the owner. It will be shown that the strategies of “Run to Failure” and “Run to Failure and Repair as Required” are overall more costly since both strategies accept corrosion, unscheduled repairs, planned failure of the pipeline and the resulting high replacement costs of the MMTP. The paper will focus on methods of design, corrosion protection, maintenance and installation which allow all MMTP materials to be equally operated and maintained for an indefinite life.

Development of a Hybrid Laser Arc Welding System for Pipeline Construction

Scipedia content — Thu, 28 Jan 2021 17:05:50 +0100

The construction costs for a northern pipeline will represent approximately half of the project costs and will be extremely challenging with much of the work being carried out in harsh winter conditions at temperatures, as low as −55°C. The welding costs are a major component of the overall construction costs and industry continues to seek future generation pipeline welding technologies to achieve additional improvements in productivity and enable significant cost savings. The current state-of-the-art welding processes for onshore pipelines involve mechanized gas metal arc welding (GMAW). The dual tandem pulse GMAW process provides the greatest productivity to date with four welding arcs operating simultaneously on each welding carriage. Based on the progression of laser welding technology, it is highly likely that the next generation of automated pipeline welding equipment will be built around hybrid laser arc welding (HLAW). The primary objective of this project is to develop, test, and validate a “field ready” HLAW system for full circumferential girth welding of large diameter (NPS30 and above) high strength pipe. The system is based on both robotic and direct clamp-on platforms where potential applications include double jointing operations in pipe mills and as well for onshore and offshore pipeline construction projects. The pipe grades evaluated include both X80 and X100, with wall thicknesses of 10.4mm and 14.3mm, respectively. Lab trials include high speed root pass, high speed root pass with laser assisted GMAW for fill and cap passes, and, single pass complete joint penetration girth welding. This paper discusses the approach to the development of the HLAW system, however at the time the paper was submitted no mechanical testing or system validation trials had been completed. It is expected results will be available for the conference presentation.

Horizontal Directional Drilling with Ductile Iron Pipe

Scipedia content — Thu, 28 Jan 2021 17:05:14 +0100

Since its development in 1948, and its introduction by the industry in 1955, Ductile Iron Pipe has become the most widely used product for water line installations. In conjunction with water line installations, Ductile Iron Pipe has become often used for gravity and force main sewer applications. Following a tradition with hundreds of years of history, Ductile Iron Pipe was a logical progression from its predecessor, Cast Iron Pipe. Ductile Iron Pipe has been widely embraced due to its inherent strength, ease of field adaptability, and myriad of joint options. When the directional drilling method of pipeline installation was first introduced to the United States, members of the ductile iron pipe industry did not view their product as applicable to this method of installation. The reason; it was incorrectly believed that the directional drilling installation method required a pipe material with a uniform outside diameter throughout the entire pipe length. Consequently research and development efforts were put into action to design and test a ductile iron pipe restrained joint with a uniform outside diameter. During this time of Research and Development by the Ductile Iron Pipe Manufacturers, Horizontal Directional Drilling became a rapidly growing form of pipeline utility installation. There are several key reasons for this installation method growth. Some of the reasons are utility replacement in areas of well maintained landscape, residential areas with well maintained streets and driveways, as well as highly sensitive Historical areas. Open trench construction techniques can be very disruptive and controversial in these sensitive areas. Environmentally sensitive areas have also proven to be key areas where Horizontal Directional Drilling installation methods lessen if not eliminate impact on environmentally sensitive areas.

Long-term and mid-term mobility decisions during the life course: Experiences with a retrospective survey

Scipedia content — Tue, 26 Jan 2021 17:52:20 +0100

Long-term and mid-term mobility of people involves on the one hand decisions about their residential locations and the corresponding moves. At the same time, the places of education and employment play an important role. On the other hand the ownership of mobility tools, such as cars and different public transport season tickets, is a complementary element in this process, which also binds substantial resources. These two aspects of mobility behaviour are closely connected to one another. A longitudinal perspective on these relationships is available from people's life courses, which link different dimensions of life together. Besides the personal and familial history, locations of residence, education and employment as well as the ownership of mobility tools can be taken into account. These life course dimensions are usually not independent from one another. Events in one area are frequently connected to changes in other areas. At the same time, this longitudinal approach provides the possibility to observe developments over time. In order to study the dynamics of long-term and mid-term mobility decisions, a longitudinal survey covering the 20-year period from 1985 to 2004 was carried out at the beginning of 2005 in a stratified sample of municipalities in the Zurich region, Switzerland. The paper shows that there exists a strong interrelation between the two examined aspects of long-term and mid-term mobility. The residential mobility is influenced by the ownership of the different mobility tools, and vice versa. Thereby the mobility tool ownership remains comparably stable over longer periods of time. Concerning the ownership of the various mobility tools, the analyses indicate that car ownership and public transport season ticket ownership substitute one another. During the life course car ownership is highest among those who are 35 to 55 years old today. At the same time, men have noticeably more frequently a car at their disposal than women of the same age. Concerning the ownership of national and regional season tickets, the opposite trend is visible. ISSN:0386-1112 ISSN:2210-4240

Multi-region GMPLS control and data plane integration

Scipedia content — Tue, 26 Jan 2021 17:13:29 +0100

GMPLS is a still developing protocol family which is indented to assume the role of a control plane in transport networks. GMPLS is designed to provide traffic engineering in transport networks composed of different network technologies such as wavelength switched optical networks, Ethernet networks, point-to-point microwave links, etc. Integrating the different network technologies while using label switched paths to provide traffic engineering poses a challenge. The purpose of integrating multiple technologies under a single GMPLS control plane is to enable rapid service provisioning and efficient traffic engineering. Traffic engineering in networks provides two primary advantages, network resource utilization optimization and the ability to provide Quality of Service. Utilizing network resources more efficiently translates to lower expenditures for the network provider. Quality of Service can be used to provide the customer with for example guaranteed minimum bandwidth packet services. Specifically this thesis focused on the problems of signaling and establishing Forward Adjacency Label Switched Paths (FA-LSPs), and on a experimental method of connecting different network technologies. A testbed integrating an Ethernet network and a wave length division multiplexing network was used to show that the proposed solutions can work in practice. GMPLS består av en samling protokoll under utveckling, de är tänkta att anta rollen som kontrollplan i transportnätverk. GMPLS är designat för att tillhandahålla trafikplanering i transportnätverk bestående av flera olika nätverksteknologier såsom Ethernet, våglängds switchande nätverk m.fl. Integration av dessa olika nätverksteknologier under ett gemensamt kontrollplan och uppsättning av ”label switched paths” i dataplanet är en utmaning. Syftet med att integrera multipla teknologier under ett ensamt GMPLS kontroll plan är att snabbt kunna tillhandahålla tjänster över nätverket samt möjliggöra advancerad trafikplanering. Trafikplanering i nätverk ger två stora fördelar, optimering av utnyttjandet av nätverksresurser samt ökade möjligheter att erbjuda ”Quality of Service” till kunder. Bättre utnyttjande av nätverksresurser innebär lägre kostnader för nätverksleverantören medans ”Quality of Service” kan ge kunden t.ex. en garanterad bandbredd. Specifikt fokuserar denna avhandling på problemen med att signalera och etablera ”Forwarding Adjaceny Label Switched Paths” samt en experimentell metod som båda sammankopplar olika typer av nätverk. En testbed bestående av ett Ethernet nätverk samt ett optiskt våglängdsswitchande nätverk användes för att visa att lösningarna kan fungera i praktiken.

Traffic Engineering with Multi-Protocol Label Switching, Performance Comparison with IP networks

Scipedia content — Tue, 26 Jan 2021 16:40:10 +0100

Traffic Engineering (TE) is the stage which deals with geometric design planning and traffic operation of networks, network devices and relationship of routers for the transportation of data. TE is that feature of network engineering which concentrate on problems of performance optimization of operational networks. It involves techniques and application of knowledge to gain performance objectives, which includes movement of data through network, reliability, planning of network capacity and efficient use of network resources. This thesis addresses the problems of traffic engineering and suggests a solution by using the concept of Multi-Protocol Label Switching (MPLS). We have done simulation in Matlab environment to compare the performance of MPLS against the IP network in a simulated environment. MPLS is a modern technique for forwarding network data. It broadens routing according to path controlling and packet forwarding. In this thesis MPLS is computed on the basis of its performance, efficiency for sending data from source to destination. A MATLAB based simulation tool is developed to compare MPLS with IP network in a simulated environment. The results show the performance of MPLS network in comparison of IP network. YASSAR AZIZ, +46 73 9135296 MUHAMMAD NAEEM ASLAM +46 70 4918985

Station-nearness Principles in the Copenhagen Region and Scania, Integrating Urban Functions with Public Transit

Scipedia content — Tue, 26 Jan 2021 16:37:44 +0100

Station-nearness principles as we will discuss in this paper, deals with the coordination of urban functions with the public transportation network. When we talk about functions, we mean residences, workplaces, commercial services, entertainment venues, places of culture, etc. These functions should be high density, there should be a mix of them and they should be pedestrian friendly in nature. Effective integration of functions around train stations brings many benefits and is one of the best means by which you can increase public transport use and increase the accessibility for people in a region. More and more, cities in North America, Europe and other places, are exploring the idea of how this concept can be applied. The Copenhagen region as we will discuss, has placed station-nearness principles at the forefront of their finger plan. Since the Copenhagen region has applied these principles, they have seen clear results with increased public transit ridership, as well on the overall, an increase in the standard of living. As many places are exploring the concept, not everyplace has been able to make the concept work. When we look at Scania, the concept is under utilized to a degree. There continues to be many populated and dense areas in Scania where the coordination of urban functions with public transit is lacking. The automobile is also gaining stronger competition over public transportation; this is a concern in terms of the sustainable future and quality of life for the region. It is not always the solution to simply expand the public transportation network, rather it can be significant to explore more upon the concept of station-nearness principles so that the existing public transit network can be made more effective. It is important to compare places, see in our case study how the concept has worked in the Copenhagen region and look into why the concept is lacking in Scania, as well, what can be done to implement it more in Scania. It is also important how the Öresund region as whole, can play a role with developing the concept, as well, how the concept can benefit the Öresund region vice versa.

Design and validation of advanced driver assistance systems

Scipedia content — Tue, 26 Jan 2021 16:18:45 +0100

This thesis presents new tools and methods for the design and validation of advanced driver assistance systems (ADASs). ADASs aim to improve driving comfort and traffic safety by assisting the driver in recognizing and reacting to potentially dangerous traffic situations. A major challenge in designing these systems is to guarantee high performance and dependability under all possible combinations of traffic scenarios, operating conditions, and failure modes. These stringent requirements necessitate fault-tolerant control techniques and a thorough validation of the system. A microscopic traffic simulation within the simulation environment PreScan supports the initial system design. In addition, a unique tool for the design and validation of ADASs is presented and evaluated: vehicle hardware-in-the-loop (VeHIL) simulation. The VeHIL laboratory allows an ADAS-equipped vehicle to be tested in an artificial environment, where surrounding traffic is emulated by robot vehicles. VeHIL enables repeatable, safe, and accurate testing, complementary to human-in-the-loop test drives. The use of these three tools (PreScan, VeHIL, and test drives) is combined in a methodology for probabilistic validation of ADASs, based on randomized algorithms. This methodology is more efficient than conventional simulation techniques and the current practice of trial-and-error test drives. It results in a test schedule definition with a minimum number of simulations and test runs, such that the performance and dependability of an ADAS can be guaranteed, given a desired level of accuracy and confidence. The added value of the methodology is demonstrated with three case studies, involving a driver information and warning system, a fault-tolerant system for cooperative adaptive cruise control, and a pre-crash system.

Ease-of-Use in Public Transportation : A User Perspective on Information and Orientation Aspects

Scipedia content — Tue, 26 Jan 2021 15:52:26 +0100

This interdisciplinary thesis combines psychological and transportation planning knowledge. Three main questions are investigated: 1) What concepts and ideas do people have with regard to a public transportation system (cognitive user perspective)?; 2) What orientation and information factors within the public transportation system enhance Ease-of-Use and make it simpler and more efficient to use public transportation in metropolitan areas?; 3) How can Ease-of-Use of a public transportation route be measured? A combination of qualitative and quantitative methods was used. Between 2002 and 2007 a total of nine different studies were conducted: An in-depth study on a single exchange student, an interview study with exchange students, a questionnaire study on exchange students, a before-after interview study with travellers on selected bus stops, an before-after telephone interview study on residents, an expert questionnaire study via email, a behaviour observation study on travellers, a before-after questionnaire study on travellers on a tram line, and an on-board questionnaire study. To analyse the cognitive user perspective the term memory representation was introduced, that includes cognitive maps of and additional knowledge about a public transportation system such as service frequency. Memory representation is influenced by experience. Three learning phases in an unknown public transportation system are proposed and a general information search script is described. A new approach is presented regarding the organisation of public transportation knowledge: The ground level is that there exists a public transportation option, the next level is the identification of the mode of transport and at the highest level of the hierarchy is the code for the line. Within the second level, the public transportation mode, a hierarchical structure of public transportation option knowledge is proposed. Three factors are postulated that contribute to the extent to which a line is represented in people’s memory: visibility, straight route layout and labelling. Which orientation and information factors within the public transportation system enhance Ease-of-Use, i.e. match the cognitive user perspective? It was found that trunk bus lines enhanced Ease-of-Use and at-stop real-time information can have various positive effects. The role of good maps is explained and stretched and the importance of consistent information throughout the travel chain is also pointed out. In addition, many valuable concrete hints are given with regard to how to match the system properly with the cognitive user perspective. Undoubtedly, an interaction exists between system and user and they influence each other. This is where the third research question comes in: How can Ease-of-Use in public transportation systems be measured? The iterative process of defining and measuring Ease-of-Use resulted in a scale that measured the defined concept well with good reliability and validity. The final discussion highlights the contribution to science of this thesis and presents some possible paths for further research. The thesis consists of a summary and eight papers. QC 20100621

Agrégation et routage de trafic dans les réseaux WDM multi-couches

Scipedia content — Tue, 26 Jan 2021 15:49:34 +0100

High-performance transport networks are expected to support applications with various types of traffic, e.g., permanent, scheduled, bursty, and noisy traffic flows. Since high-performance networks usually employ optical network infrastructures, and since most applications require sub-wavelength bandwidth, several streams are usually groomed on the same wavelength. It is therefore important that such networks are designed in an optimal way in terms of cost while efficiently supporting these types of traffic. This thesis deals with the design and analysis of optical networks allowing for traffic engineering including grooming and rerouting functionalities. Both deterministic and random traffic scenarios are considered. As a first step, optimal as well as accurate heuristic approaches are developed for network design and operation under deterministic traffic conditions. As a second step, under random traffic conditions, the dynamic routing and grooming problem is considered subject to the availability of free network resources. Several algorithms are developed to facilitate this provisioning problem. At last, rerouting techniques are addressed. We investigate different rerouting strategies and their implementation in order to enhance network efficiency under specific traffic scenarios.; Les réseaux de transport haut-débit doivent être capable de pouvoir transporter à la fois différents types de trafic ; permanent, planifié, sporadique, et même aléatoire. En général, de tels réseaux sont déployés en utilisant une infrastructure optique offrant des canaux de transmission permettant des débits de plusieurs Gigabits par seconde. Cependant, la plupart des applications actuellement existantes exigent une bande passante inférieure à celle-ci, d'où la nécessité de pouvoir agréger plusieurs demandes sur le même canal optique. Il est donc important que ces réseaux soient conçus de manière optimale en termes de coût tout en permettant le transport efficace de ces types de trafic. Cette thèse porte sur la conception et l'analyse de réseaux optiques permettant l'ingénierie de trafic englobant les fonctions d'agrégation et de reroutage. Dans notre étude, nous considérons simultanément des demandes de trafic déterministes et d'autres aléatoires. Dans un premier temps, une solution exacte ainsi qu'une approche heuristique sont développées pour le problème de dimensionnement de réseaux multi-granulaires dans le cas de demandes déterministes. Dans un deuxième temps, le problème de routage et d'agrégation dynamique des demandes aléatoires est examiné sous réserve de la disponibilité de ressources libres dans le réseau. Plusieurs algorithmes sont développés pour faciliter ce problème de provisionnement. Enfin, des techniques de reroutage de trafic sont abordées. Nous étudions différentes stratégies de reroutage et leur application en vue d'améliorer l'efficacité du réseau quand ce dernier transporte à la fois des demandes de trafic planifiées et d'autres aléatoires.

Model-Based Visual Localisation Of Contours And Vehicles

Scipedia content — Tue, 26 Jan 2021 15:35:50 +0100

El treball d'aquesta tesi es centra en l'anàlisi de seqüències de vídeo, aplicant tècniques basades en models per extreure'n informació quantitativa. En concret, es realitzen diferents propostes en dues àrees d'aplicació: el seguiment de formes basat en models de contorns, i la detecció i seguiment de vehicles en imatges proveïdes per una camera instal·lada en una plataforma mòbil."br/"El treball dedicat al seguiment de formes s'enquadra en el paradigma de contorns actius, del qual presentem una revisió de les diferents propostes existents. En primer lloc, mesurem el rendiment obtingut pels algorismes de seguiment més comuns (filtres basats en Kalman i filtres de partícules), i en segon lloc avaluem diferents aspectes de la seva implementació en un extens treball experimental on es consideren múltiples seqüències sintètiques, distorsionades amb diferents graus de soroll. Així, mitjançant aquest estudi determinem la millor manera d'implementar a la pràctica els algorismes de seguiment clàssics, i identifiquem els seus pros i contres."br/"Seguidament, el treball s'orienta cap a la millora dels algoritmes de seguiment de contorns basats en filtres de partícules. Aquest algorismes aconsegueixen bons resultats sempre que el número de partícules utilitzades sigui suficient, però malauradament la quantitat de partícules requerides creix exponencialment amb el número de paràmetres a estimar. Per tant, i en el context del seguiment de contorns, presentem tres variants del filtre de partícules clàssic, corresponents a tres noves estratègies per tractar aquest problema. En primer lloc, proposem millorar el seguiment de contorns mirant de propagar més acuradament les partícules emprades per l'algorisme d'una imatge a la següent. Això ho duem a terme utilitzant una aproximació lineal de la funció de propagació òptima. La segona estratègia proposada es basa en estimar part dels paràmetres de manera analítica. Així, es pretén fer un ús més productiu de les partícules emprades, reduint la part dels paràmetres del model que s'han d'estimar amb elles. El tercer mètode proposat té com a objectiu treure profit del fet de que, en aplicacions de seguiment de contorns, sovint els paràmetres relatius a la transformació rígida es poden estimar prou acuradament independentment de la deformació local que el contorn presenti. Això s'utilitza per realitzar una millor propagació de les partícules, concentrant-les més densament en la zona on el contorn seguit es troba. Aquestes tres propostes es validen de manera extensiva en seqüències amb diferents nivells de soroll, amb les que es mesura la millora aconseguida."br/"A continuació proposem tractar directament l'origen del problema anterior mitjançant la reducció del nombre de paràmetres a estimar per tal de seguir una determinada forma d'interès. Per aconseguir això, proposem modelar aquesta forma usant múltiples models, on cadascun requereix una quantitat de paràmetres inferior a la requerida per un únic model. Es proposa un nou mètode per aprendre aquests models a partir d'un conjunt d'entrenament, així com un nou algorisme per emprar-los en el seguiment dels contorns. Els resultats experimentals certifiquen la validesa d'aquesta proposta."br/"Finalment, la tesi es centra en el desenvolupament d'un sistema de detecció i seguiment de vehicles. Les propostes realitzades comprenen: un mòdul de detecció de vehicles, un mòdul dedicat a determinar la posició i velocitat 3D dels vehicles detectats, i un mòdul de seguiment per actualitzar la localització dels vehicles a la carretera de manera precisa i eficient. Es realitzen diverses aportacions originals en aquests tres temes, i se n'avalua el rendiment.

This thesis focuses the analysis of video sequences, applying model-based techniques for extracting quantitative information. In particular, we make several proposals in two application areas: shape tracking based on contour models, and detection and tracking of vehicles in images acquired by a camera installed on a mobile platform."br/"The work devoted to shape tracking follows the paradigm of active contours, from which we present a review of the existent approaches. First, we measure the performance of the most common algorithms (Kalman based filters and particle filters), and then we evaluate its implementation aspects trough an extensive experimental study, where several synthetic sequences are considered, distorted with different degrees of noise. Thus, we determine the best way to implement in practice these classical tracking algorithms, and we identify its benefits and drawbacks."br/"Next, the work is oriented towards the improvement of contour tracking algorithms based on particle filters. These algorithms reach good results provided that the number of particles is high enough, but unfortunately the required number of particles grows exponentially with the number of parameters to be estimated. Therefore, and in the context of contour tracking, we present three variants of the classical particle filter, corresponding to three new strategies to deal with this problem. First, we propose to improve the contour tracking by propagating more accurately the particles from one image to the next one. This is done by using a linear approximation of the optimal propagation function. The second proposed strategy is based in estimating part of the parameters analytically. Thus, we aim to do a more productive use of the particles, reducing the amount of model parameters that must be estimated through them. The third proposed method aims to exploit the fact that, in contour tracking applications, the parameters related to the rigid transform can be estimated accurately enough independently from the local deformation presented by the contour. This is used to perform a better propagation of the particles, concentrating them more densely in the zone where the tracked contour is located. These three proposals are validated extensively in sequences with different noise levels, on which the reached improvement is evaluated."br/"After this study, we propose to deal directly with the origin of the previous problem by reducing the number of parameters to be estimated in order to follow a given shape of interest. To reach that, we propose to model the shape using multiple models, where each one requires a lower quantity of parameters than when using a unique model. We propose a new method to learn these models from a training set, and a new algorithm to use the obtained models for tracking the contours. The experimental results certify the validity of this proposal."br/"Finally, the thesis focuses on the development of a system for the detection and tracking of vehicles. The proposals include: a vehicle detection module, a module devoted to the determination of the three-dimensional position and velocity of the detected vehicles, and a tracking module for updating the location of vehicles on the road in a precise and efficient manner. Several original contributions are done in these three subjects, and their performance is evaluated empirically.

Optimizing Application Traffic on MPLS-Enabled Network Links.

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

The expectations of every user of today’s internet is becoming relatively high more especially as the internet applications are becoming steadily sensitive to time and delays. The critical nature of some of these applications is more apparent now that they are real-time. These pose a whole lot of challenges to network operators and service providers because they will not only need to provide these services to users but also ensure that these services rendered meet up to quality expectations and standards. It is therefore very necessary and important for them to provide good quality of service with appreciable good performance at no incurable costs- that is while maximizing revenue- to them. A need therefore arises for the adoption of a scalable method or tool for meeting up to these challenges. Multi-Protocol Label Switching (MPLS) stands out to be the choicest tool and key for providing these requirements because of its traffic engineering (TE) capability in IP network and as such the internet needs to be equipped with this all-embracing technology. This report presents the performance analysis of this technology (MPLS TE) vis-à-vis the traditional IP with respect to the average throughput, Quality of service rendered, delay suffered and minimization of congestions or traffic overflow in a bid to seeing how and why MPLS is more capable in optimizing traffic applications when adopted by service providers and network operators. And from the conclusion of the analysis and results it would have been established that MPLS appeared to be more capable in the optimization of traffic applications with respect to the above characteristics when compared with the traditional IP.

The Tragedy of Ordinarity : Culture Constraints on Sustainable Development Based on Public Transport

Scipedia content — Tue, 26 Jan 2021 15:31:23 +0100

This licentiate thesis consists of two free-standing papers and a linking essay that links the papers by articulating an overall research aim and common theoretical background. The research aim is kept general and focuses on the role public transport can play in sustainable development. The work aims to contribute to a better understanding of why people do or do not choose to use public transport, to grasp the ideas/attitudes underlying the decisions made regarding the future of public transport, and to make suggestions for solving problems that may arise in public transport. The thesis has three theoretical bases: transport research, cultural theory, and sustainable development. Transport research is the starting point of the work, and I outline a gap in it that needs to be filled. This gap is filled by drawing on cultural theory connected to geographic terms. Sustainability discourses, on one hand, legitimate the work’s importance but also further stimulate the linking essay. Methodologically, the thesis can be placed in the hermeneutic tradition. Due to the work’s particular alignment with cultural theory, cultural relativism is supported. In addition, the interdisciplinary and multi-methodical approach can be explained by the work’s cultural focus. Against this background, the research concluded that, as a business, public transport has difficulties achieving the vaguely formulated ideological goals set for it at the national political level. As well, citizens have been marginalised in the goal-setting process. Citizen empowerment and a clearer formulation of the ideological goals are needed. Furthermore, public transport seems to be poorly rooted in society, and the present research found subregional differences that might be culturally based or explainable. The fact that public transport is poorly rooted in society can partially be explained by the marginalisation of citizens from decision making. Cultural differences in and between subregions should thus be taken into account by a farther-reaching customer perspective that acknowledges the importance of subregions. In conclusion, one should be sceptical as to public transport’s role in sustainable development. This pessimism arises from the technological step backward people would have to take in changing their main mode of transportation. Therefore, more all-embracing technical innovations are needed in the transport sector.

İstanbul’da Ulaştırma Sisteminin Sürdürülebilirliğinin Değerlendirilmesi

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

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2008

İstanbul İlindeki Toplu Taşıma Yolculuk Taleplerinin Yapay Sinir Ağlarıyla Modellenmesi

Scipedia content — Tue, 26 Jan 2021 13:46:11 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2008

Optimization of an Electric Three Wheel Vehicle. Traction System

Scipedia content — Tue, 26 Jan 2021 13:44:14 +0100

Outgoing

Toplu Taşıma Sistemlerinde Müşteri Odaklı Performans Değerlendirmesi

Scipedia content — Tue, 26 Jan 2021 13:14:33 +0100

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2008

Full Account of the Costs and Benefits of Reducing CO2 Emissions in Transport

Scipedia content — Mon, 25 Jan 2021 20:24:21 +0100

mong economists and policy makers more general, the fuel efficiency standard for cars and the fuel tax have been the subject of extensive debate. The major benefits of stricter fuel efficiency standards and higher fuel taxes are the reduction of Greenhouse gas emissions and the reduced oil dependence. The major costs are the increased production cost, the reduced comfort and the negative impact on mileage related externalities (congestion, accidents) due to the rebound effect. In this contribution we use a wider framework than Harrington (2008), Plotkin (2008) and Raux (2008) to discuss the CO2 1 emission reduction in transport. In section 2 we analyze, for the EU, the effects on welfare and CO2 emissions of pricing all transport activities according to their full social costs. In section 3, we go beyond the transport sector and compare the options to reduce emissions in the transport sector with the possibilities and costs to reduce emissions in other sectors of the economy. In section 4 we take a world view and analyze the impact of two types of international climate negotiations on the emission reduction strategy in the transport sector.

New York Household Travel Patterns: A Comparison Analysis

Scipedia content — Mon, 25 Jan 2021 20:18:58 +0100

In 1969, the U. S. Department of Transportation began collecting detailed data on personal travel to address various transportation planning issues. These issues range from assessing transportation investment programs to developing new technologies to alleviate congestion. This 1969 survey was the birth of the Nationwide Personal Transportation Survey (NPTS). The survey was conducted again in 1977, 1983, 1990 and 1995. Longer-distance travel was collected in 1977 and 1995. In 2001, the survey was renamed to the National Household Travel Survey (NHTS) and collected both daily and longer-distance trips in one survey. In addition to the number of sample households that the national NPTS/NHTS survey allotted to New York State (NYS), the state procured an additional sample of households in both the 1995 and 2001 surveys. In the 1995 survey, NYS procured an addition sample of more than 9,000 households, increasing the final NY NPTS sample size to a total of 11,004 households. Again in 2001, NYS procured 12,000 additional sample households, increasing the final New York NHTS sample size to a total of 13,423 households with usable data. These additional sample households allowed NYS to address transportation planning issues pertinent to geographic areas significantly smaller than for what the national NPTS and NHTS data are intended. Specifically, these larger sample sizes enable detailed analysis of twelve individual Metropolitan Planning Organizations (MPOs). Furthermore, they allowed NYS to address trends in travel behavior over time. In this report, travel data for the entire NYS were compared to those of the rest of the country with respect to personal travel behavior and key travel determinants. The influence of New York City (NYC) data on the comparisons of the state of New York to the rest of the country was also examined. Moreover, the analysis examined the relationship between population density and travel patterns, and the similarities and differences among New York MPOs. The 1995 and 2001 survey data make it possible to examine and identify travel trends over time. This report does not address, however, the causes of the differences and/or trends.

Measuring the intellectual capital of international carriers as logistic operators

Scipedia content — Mon, 25 Jan 2021 19:18:52 +0100

The age of knowledge has come and the enterprises present themselves as "knowledge enterprises" and their employees as sources of knowledge - "knowledge workers". Knowledge has become a merchandise, to be on the knowledge market. In an enterprise knowledge becomes the capital, important for achieving competitive advantage on the market but it cannot be measured easily. The field of intellectual capital is very complex, mostly because it is difficult to categorize it. The important concepts and definitions for intellectual capital include an emphasis that intellectual capital is based on knowledge and is usable in any enterprise. Knowledge and skills determine the possibilities of an individual to actively influence the social development and ensure their quality of life. Prišla je doba znanja in podjetja se vse bolj predstavljajo kot »podjetja znanj«, svoje zaposlene pa kot vire znanja »Znanjske delavce«. Znanje je postala blago, ki se menja na trgu znanja, v podjetju pa postaja kapital, ki je pomemben za doseganje konkurenčne prednosti na trgu, vendar ga je težko izmeriti. Področje intelektualnega kapitala je zelo kompleksno predvsem zato, ker gre za kategorijo, katero je zelo težko meriti. Pomembnejši koncepti in opredelitve intelektualnega kapitala vsebujejo poudarek, da je intelektualni kapital nekaj, kar bazira na znanju in je uporabno v podjetju. Znanje in veščine opredeljujejo možnosti posameznika, da dejavno vpliva na družbeni razvoj in si zagotavlja kakovostno življenje.

Green Paper : Towards a new culture for urban mobility

Scipedia content — Mon, 25 Jan 2021 19:18:10 +0100

Importance of Oil Price in Freight Transport Costs

Scipedia content — Mon, 25 Jan 2021 18:51:21 +0100

Le petrole fournit la quasi-totalite du carburant pour les transports. Or le prix du petrole brut (FOB-Free on board) ne constitue pour l’instant qu’une petite partie des couts du transport, moins du cinquieme. Les quatre cinquiemes des couts du transport proviennent des frais d’exploitation, des salaires et de la fiscalite. Neanmoins, si la rarefaction du petrole venait a faire exploser les couts du carburant, elle produirait des effets negatifs forts. Une multiplication par 8 du prix du petrole (par rapport a 2007) doublerait le cout des transports de marchandises. Toutefois la hausse de couts serait suffisamment uniforme pour que les exploitants puissent les repercuter sur les clients sans que la concurrence ne soit profondement modifiee. Les petits exploitants ne pouvant pas s’organiser pour optimiser les chargements et les itineraires seraient les plus menaces. La mobilite des personnes serait par contre tres touchee sur deux aspects : la voiture particuliere et l’aviation. Le cas de l’aviation est bien connu (surtaxes kerosene), par contre le probleme du transport individuel –qui consomme environ la meme quantite de carburant que l’aviation par passager et par kilometre- risque d’aboutir a une societe ou seuls les citoyens les plus aises restent reellement mobiles. Importance of Oil Price in Freight Transport Costs Oil is the main component of transport fuel. As for now, however, crude oil price (FOB-Free on board) accounts for less than a fifth of transport costs. Operating costs, wages and taxes cause the remaining four fifths. Nevertheless, oil scarcity may raise fuel costs to such a level that transport companies and citizen may suffer significant adverse impacts. A multiplication by 8 of the price of oil (compared to 2007) would double road transport cost. Yet, the rise would be global, which would enable operators to shift the cost to their clients without suffering changes in competition. Still, small operators that would not be in a position to optimize truck loads and routes would be threatened. Major oil price rise would mainly affect two aspects of mobility: aviation and private motoring. Air companies have added a special oil charge to ticket cost while changes in private motoring, which uses approximately as much fuel as air per passenger – kilometre, may lead to a situation where only the wealthiest citizens may keep driving.

Remaining Sites Verification Package for the 100-C-9:2 Sanitary Sewer Pipelines, Waste Site Reclassification Form 2004-013

Scipedia content — Mon, 25 Jan 2021 18:41:11 +0100

The 100-C-9:2 sanitary sewer pipelines include the feeder pipelines associated with the 1607-B8, the 1607-B9, the 1607-B10 and the 1607-B11 septic systems. Contaminated soil and piping from the feeder lines to the septic systems were removed and disposed of. The remaining soil in the excavations has been shown to meet the remedial action objectives specified in the Remaining Sites ROD. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

Stressed glass technology for actuators and removable barrier applications.

Scipedia content — Mon, 25 Jan 2021 18:34:46 +0100

There are commercial and military applications in which a material needs to serve as a barrier that must subsequently be removed. In many cases it is desirable that once the barrier has served its function that it then be reduced to small pieces. For example, in pipelines and in downhole drilling applications, valves are needed to function as barriers that can sustain high pressures. Later the valves must be removed and essentially disappear or be rendered to such a small size that they do not interfere with the functioning of other equipment. Military applications include covers on missile silos or launch vehicles. Other applications might require that a component be used once as an actuator or for passive energy storage, and then be irreversibly removed, again so as not to interfere with the function or motion of other parts of the device. Brittle materials, especially those that are very strong, or are pre-stressed, are ideal candidates for these applications. Stressed glass can be produced in different sizes and shapes and the level of strength and pre-stress, both of which control the fragmentation, can be manipulated by varying the processing. Stressed glass can be engineered to fracture predictably at a specific more » stress level. Controlling the central tension allows the fragment size to be specified. The energy that is stored in the residual stress profile that results from ion exchange or thermal tempering processes can be harnessed to drive fragmentation of the component once it has been deliberately fractured. Energy can also be stored in the glass by mechanical loading. Energy from both of these sources can be released either to perform useful work or to initiate another reaction. Once the stressed glass has been used as a barrier or actuator it can never be ''used'' again because it fragments into many small unrecognizable pieces during the actuation. Under some circumstances it will interfere with the motion or functioning of other parts of a device. Our approach was to use stressed glass to develop capabilities for making components that can be used as barriers, as actuating devices that passively store energy, or as a mechanical weaklink that is destroyed by some critical shock or crush load. The objective of this project was to develop one or more prototype devices using stressed glass technology and demonstrate their potential for applications of interest. This work is intended to provide critical information and technologies for Sandia's NP&A and MT&A customers, and is relevant to commercial applications for these same materials. Most of the studies in this project were conducted using the Corning 0317 sodium aluminosilicate glass composition. « le

Use of composite materials, health monitoring and self-healing concepts to refurbish our civil and military infrastructure.

Scipedia content — Mon, 25 Jan 2021 18:08:42 +0100

n unavoidable by-product of a metallic structure's use is the appearance of crack, corrosion, erosion and other flaws. Economic barriers to the replacement of these structures have created an aging civil and military infrastructure and placed even greater demands on efficient and safe repair and inspection methods. As a result of Homeland Security issues and these aging infrastructure concerns, increased attention has been focused on the rapid repair and preemptive reinforcement of structures such as buildings and bridges. This Laboratory Directed Research and Development (LDRD) program established the viability of using bonded composite patches to repair metallic structures. High modulus fiber-reinforced polymer (FRP) material may be used in lieu of mechanically fastened metallic patches or welds to reinforce or repair damaged structures. Their use produces a wide array of engineering and economic advantages. Current techniques for strengthening steel structures have several drawbacks including requiring heavy equipment for installation, poor fatigue performance, and the need for ongoing maintenance due to continued corrosion attack or crack growth. The use of bonded composite doublers has the potential to correct the difficulties associated with current repair techniques and the ability to be applied where there are currently no rehabilitation options. Applications include such diversemore » structures as: buildings, bridges, railroad cars, trucks and other heavy machinery, steel power and communication towers, pipelines, factories, mining equipment, ships, tanks and other military vehicles. This LDRD also proved the concept of a living infrastructure by developing custom sensors and self-healing chemistry and linking this technology with the application of advanced composite materials. Structural Health Monitoring (SHM) systems and mountable, miniature sensors were designed to continuously or periodically assess structural integrity. Such systems are able to detect incipient damage before catastrophic failure occurs. The ease of monitoring an entire network of distributed sensors means that structural health assessments can occur more often, allowing operators to be even more vigilant with respect to flaw onset. In addition, the realization of smart structures, through the use of in-situ sensors, allows condition-based maintenance to be substituted for conventional time-based maintenance practices. The sensitivity and reliability of a series of sensor systems was quantified in laboratory and real-world environments. Finally, self healing methods for composite materials were evolved--using resin modules that are released in response to the onset of delaminations--so that these components can provide a living infrastructure with minimal need for human intervention. This program consisted of four related research elements: (1) design, installation, and performance assessment of composite repairs, (2) in-situ sensors for real-time health monitoring, (3) self healing of in-service damage in a repair, and (4) numerical modeling. Deployment of FRP materials and bonded joints requires proper design, suitable surface preparation methods, and adequate surveillance to ensure structural integrity. By encompassing all 'cradle-to-grave' tasks --including design, analysis, installation, durability, flaw containment, and inspection--this program is designed to firmly establish the capabilities of composite doubler repairs and introduce technology to incorporate self-monitoring and self-healing (living structures) methodologies. A proof-of-concept repair was completed on a steel highway bridge in order to demonstrate the potential of composite doubler technology for critical infrastructure use.« le

Computer-supported modelling of multimodal transportation networks rationalization

Scipedia content — Mon, 25 Jan 2021 18:08:31 +0100

This paper deals with issues of shaping and functioning of computer programs in the modelling and solving of multimodal transportation network problems. A methodology of an integrated use of a programming language for mathematical modelling is defined, as well as spreadsheets for the solving of complex multimodal transportation network problems. The paper contains a comparison of the partial and integral methods of solving multimodal transportation networks. The basic hypothesis set forth in this paper is that the integral method results in better multimodal transportation network rationalization effects, whereas a multimodal transportation network model based on the integral method, once built, can be used as the basis for all kinds of transportation problems within multimodal transport. As opposed to linear transport problems, multimodal transport network can assume very complex shapes. This paper contains a comparison of the partial and integral approach to transportation network solving. In the partial approach, a straight forward model of a transportation network, which can be solved through the use of the Solver computer tool within the Excel spreadsheet interface, is quite sufficient. In the solving of a multimodal transportation problem through the integral method it is necessary to apply sophisticated mathematical modelling programming languages which support the use of complex matrix functions and the processing of a vast amount of variables and limitations. The LINGO programming language is more abstract than the Excel spreadsheet, and it requires a certain programming knowledge. The definition and presentation of a problem logic within Excel, in a manner which is acceptable to computer software, is an ideal basis, for modelling in the LINGO programming language, as well as a faster and more effective implementation of the mathematical model. This paper provides proof for the fact that it is more rational to solve the problem of multimodal transportation networks by using the integral, rather than the partial method. U radu je obrađena problematika oblikovanja i funkcioniranja računalnih programa u modeliranju i rješavanju problema multimodalnih transportnih mreža. Definirana je metodologija integrirane uporabe programskog jezika za matematičko modeliranje i proračunske tablice u rješavanju problema složene multimodalne transportne mreže. Uspoređene su parcijalna i integralna metoda rješavanja multimodalnih transportnih mreža. Temeljna hipoteza postavljena u ovom radu je da se integralnom metodom postižu bolji učinci racionalizacije multimodalnih transportnih mreža, pri čemu se jednom izgrađeni model multimodalne transportne mreže temeljen na integralnoj metodi, može koristiti kao temelj za sve vrste transportnih problema u multimodalnom transportu. Za razliku od linearnih transportnih problema multimodalna transportna mreža može poprimiti vrlo složene oblike. U radu su uspoređeni parcijalni i integralni pristup rješavanja transportne mreže. Kod parcijalnog pristupa dovoljan je jednostavniji model transportne mreže koji se može riješiti uporabom računalnog alata Solver u sučelju proračunske tablice Excel. U rješavanju multimodalnog transportnog problema integralnom metodom, potrebno je koristiti sofisticirane programske jezike za matematičko modeliranje koji podržavaju uporabu složenih matričnih funkcija i procesiranje velikog broja varijabli i ograničenja. Programski jezik LINGO je apstraktniji u odnosu na proračunsku tablicu Excel i zahtijeva određena znanja o programiranju. Definiranje i prezentacija logike problema u Excelu na način prihvatljiv računalnom programu predstavlja idealnu osnovu za modeliranje u programskom jeziku LINGO, te bržu i učinkovitiju implementaciju matematičkog modela. U radu je dokazano da je problem multimodalne transportne mreže racionalnije rješavati integralnom, nego parcijalnom metodom.

An Integrated Model of Downtown Parking and Traffic Congestion

Scipedia content — Mon, 25 Jan 2021 17:50:26 +0100

This paper presents a downtown parking model that integrates traffic congestion and saturated on-street parking. We assume that the stock of cars cruising for parking adds to traffic congestion. Two major results come out from the model, one of which is robust. The robust one is that, whether or not the amount of on-street parking is optimal, it is efficient to raise the on-street parking fee to the point where cruising for parking is eliminated without parking becoming unsaturated. The other is that, if the parking fee is fixed at a sub-optimal level, it is second-best optimal to increase the amount of curbside allocated to parking until cruising for parking is eliminated without parking becoming unsaturated.

Optimizing departure times in vehicle routes

Scipedia content — Mon, 25 Jan 2021 17:49:33 +0100

Most solution methods for the vehicle routing problem with time windows (VRPTW) develop routes from the earliest feasible departure time. However, in practice, temporal traffic congestions make that such solutions are not optimal with respect to minimizing the total duty time. Furthermore, VRPTW solutions do not account for complex driving hours regulations, which severely restrict the daily travel time available for a truck driver. To deal with these problems, we consider the vehicle departure time optimization (VDO) problem as a post-processing step of solving a VRPTW. We propose an ILP-formulation that minimizes the total duty time. The obtained solutions are feasible with respect to driving hours regulations and they account for temporal traffic congestions by modeling time-dependent travel times. For the latter, we assume a piecewise constant speed function. Computational experiments show that problem instances of realistic sizes can be solved to optimality within practical computation times. Furthermore, duty time reductions of 8 percent can be achieved. Finally, the results show that ignoring time-dependent travel times and driving hours regulations during the development of vehicle routes leads to many infeasible vehicle routes. Therefore, vehicle routing methods should account for these real-life restrictions.

Remaining Sites Verification Package for the 1607-F4 Sanitary Sewer System, Waste Site Reclassification Form 2004-131

Scipedia content — Mon, 25 Jan 2021 17:39:03 +0100

The 1607-F4 waste site is the former location of the sanitary sewer system that serviced the former 115-F Gas Recirculation Building. The system included a septic tank, drain field, and associated pipeline that were in use from 1944 to 1965. The 1607-F4 waste site received unknown amounts of sanitary sewage from the 115-F Gas Recirculation Building and may have potentially contained hazardous and radioactive contamination. In accordance with this evaluation, the verification sampling results support a reclassification of this site to Interim Closed Out. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

Productivity in the Transportation Sector

Scipedia content — Mon, 25 Jan 2021 17:07:04 +0100

This is a comprehensive study of measurement and substantive issues that arise in determining the rate of multi factor productivity (MFP) growth in the transportation industry over the postwar period, 1948-87. Official data on output and employment are provided by two government agencies and conflict markedly for railroads, airlines, and trucking. This paper identifies the source of the conflicts and selects the best of the government indexes for further study, It concludes that improved data reduce the magnitude of the post-1973 productivity slowdown in transportation MFP growth from a previously reported 2.5 percent per annum to just 0.5 percent. The effect of deregulation has been mixed; MFP growth accelerated markedly for railroads when 1978-87 is compared to the pre-1978 period, but slowed sharply for airlines and trucking. New results on output quality are provided for airlines, particularly for the period of deregulation. Contrary to the standard view, deregulation has not substituted circuitous routings through hubs for nonstop flights available previously; instead the establishment of new hubs has greatly increased the number of nonstop routings available, and remarkably few nonstop routes have been discontinued. An estimate is provided of the value of time saved by the improved routings, and of the offsetting time cost of extended scheduled flight times resulting from increased congestion. Such estimates of the value of time are swamped by the huge contribution to welfare provided by the manufacturers of aircraft and engines; the time saving from the "invention of air travel" for 1989 is valued at 400 percent of domestic airline revenue and 3.5 percent of GNP. Alternative measures of capital input, based on new quality-adjusted equipment deflators, are provided for airlines, railroads, and trucking. These uniformly increase faster in the earlier postwar years than in the last decade and consequently imply a smaller decline in MFP growth than in official data sources. However, new estimates of the input of government expenditures on airports, air traffic control, and highways, do not change appreciably the pattern of postwar MFP growth in transportation.

Accessibility: Long Term Perspectives

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

Improved accessibility and its correlate lower generalized cost of contact, travel and transport have been sought by dynamic human societies for their economic and social benefits through- out recorded history. The paper will reflect about this process at a number of different spatial and temporal scales based on a conceptual model. Looking back at European history, it will trace the interaction between Christaller’s logic of local market areas and the idea of (low contact cost) network cities. Focusing on Switzerland since 1950 it will show how network investment changed the relative distribution of population and employment and how this in- teracted with changes in the preferences of the travelers. Using a recent snapshot of how a substantial sample of Swiss maintain their social networks over often very large areas, it will try to answer the question of what will happen in the future, if the current trend of ever lower costs of contact will persist. ISSN:1938-7849

Assessing the Environmental, Forest, and Other Natural Resource Aspects of Development Policy Lending : A World Bank Toolkit

Scipedia content — Mon, 25 Jan 2021 16:55:10 +0100

The operations policy on Development Policy Lending (DPL), approved by the Board in August 2004, requires that the Bank systematically analyze whether specific country policies supported by an operation are likely to have "significant effects" on the country's environment, forests, and other natural resources. The implicit objective behind this requirement is to ensure that there is adequate capacity in the country to deal with adverse effects on the environment, forests, and other natural resources that the policies could trigger, even at the program design stage. DPL operations are associated with a whole array of policies such as macro policy reforms, fiscal policies, and specific sectoral policies, particularly in key sectors such as agriculture, health and education, energy, etc. In some cases, the operation may deal directly with reforms in certain environmentally sensitive sectors such as energy, transport, water and sanitation, agriculture, and forestry. In these cases, there is an obvious need for careful analysis of environmental, natural resource, and forestry impacts. In other cases, such as public sector reform and governance, there is less potential for likely significant impacts on the natural environment and natural resources. The toolkit is designed to be concise and user-friendly. It consists of three specific modules. The first module identifies relevant transmission channels through which the proposed reform would have a likely effect on the identified environmental, forest, and other natural resource priorities. The second module provides assistance in identifying key environmental issues in the country, regions, or sectors likely to be influenced by the DPL program. The third module presents different tools and methodologies for rapid assessment of the likely significant effects of each reform.

Multicriteria optimisation in logistics forwarder activities

Scipedia content — Mon, 25 Jan 2021 16:46:56 +0100

Logistics forwarder, as organizer and planner of coordination and integration of all the transport and logistics chains elements, uses adequate ways and methods in the process of planning and decision-making. One of these methods analysed in this paper, which could be used in optimisation of transport and logistics processes and activities of logistics forwarder, is the multicriteria optimisation method. Using that method, in this paper is suggested model of multicriteria optimisation of logistics forwarder activities. The suggested model of optimisation is justified in keeping with method principles of multicriteria optimization, which is included in operation research methods and it represents the process of multicriteria optimization of variants. Among many different processes of multicriteria optimization, PROMETHEE (Preference Ranking OrganizationMethod for Enrichment Evaluations) and Promcalc& Gaia V. 3.2., computer program of multicriteria programming, which is based on the mentioned process, were used. Logistički špediter, kao glavni organizator i planer koordiniranosti i integriranosti svih elemenata unutar transportnih i logističkih procesa koristi primjerene načine i metode planiranja i odlučivanja. Jedna od metoda koja može naći svoju primjenu u optimizaciji predmetnih transportnih logističkih procesa i djelatnosti logističkih špeditera, a koja je analizirana u ovoj raspravi je metoda višekriterijske optimizacije. Korištenjem te metode u ovoj raspravi je predložen model višekriterijske optimizacije aktivnosti logističkoga špeditera. Predloženi model osmišljen je u skladu s temeljnim principima metode višekriterijske optimizacije, koja spada u metode operacijskih istraživanja, a predstavlja postupak višekriterijskog rangiranja varijanti. Između više različitih postupaka višekriterijske optimizacije, korišten je postupak PROMETHEE (Preference Ranking Organization Method for Enrichment Evaluations) te računalni program višekriterijskog programiranja Promcalc & Gaia V 3.2., koji se temelji na navedenom postupku.

Private port pricing and public investment in port and hinterland capacity

Scipedia content — Mon, 25 Jan 2021 15:04:35 +0100

Abstract: Abstract We study duopolistic pricing by ports that are congestible, share the same overseas customers and have each a downstream, congestible transport network to a common hinterland. In the central set-up, local (country) governments care about local welfare only and decide on the capacity of the port and of the hinterland network. We obtain the following results. First, profit-maximizing ports internalize hinterland congestion in as far as it affects their customers. Second, investment in port capacity reduces prices and congestion at both ports, but increases hinterland congestion in the region where the port investment is made. Investment in a ports hinterland is likely to lead to more port congestion and higher prices for port use, and to less congestion and a lower price at the competing port. Third, the induced increase in hinterland congestion is a substantial cost of port investment that strongly reduces the direct benefits of extra port activities. Fourth, imposing congestion tolls on the hinterland road network raises both port and hinterland capacity investments. We illustrate all results numerically and discuss policy implications.

Exploration of a Shift in Household Transportation Spending from Vehicles to Public Transportation

Scipedia content — Mon, 25 Jan 2021 14:45:15 +0100

Despite continued and growing public support of public transit, traffic congestion continues to get worse and transit ridership and service levels have grown but not sufficiently to play a more meaningful role in addressing growing travel demands. As a result, interest continues in exploring how significant service increases might provide adequate transit capacity and sufficiently attractive service levels to attract enough ridership to offset the need of households for the current number of vehicles. Similarly, policy analysts speculate that the resources saved by households with fewer autos may represent a sufficient consumer benefit to justify or offset the higher subsidy costs necessary to provide the enhanced services. While speculation on this topic is common amongst transit planners and advocates, the literature currently offers little insight into this issue. This report estimates the average costs of private car ownership in the country based on the household income and expenditures using the Bureau of Labor Statistics (BLS) data. Travel behavior as a function of vehicle ownership is explored with the National Household Travel Survey (NHTS). Analysis of the datasets is used to develop a better understanding of the economic and travel implications potentially arising as a result of households reducing their automobile ownership. As part of the study, a scenario analysis was developed using an Excel spreadsheet tool. This tool can be used by analysts to evaluate probable consequences of reduced vehicle ownership. The analysis is driven by utilizing relationships between travel behavior, transportation spending and household vehicle availability. The research offers several observations regarding the magnitude of the behavior changes that might be expected with lower vehicle ownership as well as the capacity and cost of transit expansion required to accommodate the demands.

Class-Based OSPF Traffic Engineering Inspired on Evolutionary Computation

Scipedia content — Mon, 25 Jan 2021 12:42:41 +0100

This paper proposes a novel traffic engineering framework able to automatically provide near-optimal OSPF routing configurations for QoS constrained scenarios. Within this purpose, this work defines a mathematical model able to measure the QoS compliance in a class-based networking domain. Based on such model, the NP-hard optimization problem of OSPF weight setting is faced resorting to Evolutionary Algorithms. The presented results show that, independently of other QoS aware mechanisms that might be in place, the proposed framework is able to improve the QoS level of a given domain only taking into account the direct influence of the routing component of the network. The devised optimization tool is able to optimize OSPF weight configurations in scenarios either considering a single level of link weights or using multiple levels of weights (one for each class) in multi-topology routing scenarios.

Development of a 5 degree-of-freedom Towfish and its Control Strategy

Scipedia content — Mon, 25 Jan 2021 12:33:11 +0100

International audience; This paper describes the development of a five degree of freedom towed underwater vehicle designed for condition monitoring of undersea pipelines. Its innovative design, with 6 fins actuated by 5 motors adding heave and sway capabilities to the yaw, roll and pitch movements possible in traditional designs, is explained. The parameters influencing the stability and the design in general are analyzed. A Control strategy for this design of highly coupled movements and control modes encompassing all the operational scenarios, are presented.

Intelligent Traffic Control Decision Support System

Scipedia content — Mon, 25 Jan 2021 12:18:46 +0100

When non-recurrent road traffic congestion happens, the operator of the traffic control centre has to select the most appropriate traffic control measure or combination of measures in a short time to manage the traffic network. This is a complex task, which requires expert knowledge, much experience and fast reaction. There are a large number of factors related to a traffic state as well as a large number of possible control measures that need to be considered during the decision making process. The identification of suitable control measures for a given non-recurrent traffic congestion can be tough even for experienced operators. Therefore, simulation models are used in many cases. However, simulating different traffic scenarios for a number of control measures in a complicated situation is very time-consuming. In this paper we propose an intelligent traffic control decision support system (ITC-DSS) to assist the human operator of the traffic control centre to manage online the current traffic state. The proposed system combines three soft-computing approaches, namely fuzzy logic, neural network, and genetic algorithm. These approaches form a fuzzy-neural network tool with self-organization algorithm for initializing the membership functions, a GA algorithm for identifying fuzzy rules, and the back-propagation neural network algorithm for fine tuning the system parameters. The proposed system has been tested for a case-study of a small section of the ring-road around Riyadh city. The results obtained for the case study are promising and show that the proposed approach can provide an effective support for online traffic control.

The Big Smoke: Congestion Charging and the Environment

Scipedia content — Mon, 25 Jan 2021 12:13:52 +0100

This book chapter is from "em"Road congestion pricing in Europe : implications for the United States"/em": In February 2003, the London Congestion Charging Scheme was introduced and in 2006 a similar policy was introduced in Stockholm. In both cases automobile traffic entering the cordon declined by about 20 percent. This book evaluates these and other similar programs exploring their implications for the United States. This studyâs value lies in the fact that it examines road pricing in the real world and not simply from a theoretical viewpoint. As a comparative study it will appeal to both policymakers and academics in transportation economics and planning, urban economics, planning and economic geography.

Performance of pipelined asynchronous systems

Scipedia content — Mon, 25 Jan 2021 12:13:36 +0100

Abstract A testing-based faster-than relation has previously been developed that compares the worst-case efficiency of asynchronous systems. This approach reveals that pipelining does not improve efficiency in general; that it does so in practice depends on assumptions about the user behaviour. Accordingly, the approach was adapted to a setting where user behaviour is known to belong to a specific, but often occurring class of requestâresponse behaviours; some quantitative results on the efficiency of the respective so-called response processes were given. In particular, it was shown that in the adapted setting a very simple case of a pipelined process with two stages is faster than a comparable atomic processing of the two stages. In this paper, we determine the performance of general pipelines, which is not so easy in an asynchronous setting. Pipelines are built with a chaining operator; we also study whether the adapted faster-than relation is compatible with chaining and two other parallel composition operators, and give results on the performance of the respective compositions. These studies also demonstrate how rich the requestârespond setting is.

Car users' acceptability of a kilometre charge

Scipedia content — Mon, 25 Jan 2021 11:58:52 +0100

Transport pricing is high on the political agenda throughout the world, but as the authors illustrate, governments seeking to implement this often face challenging questions and significant barriers. The associated policy and research questions cannot always be addressed adequately from a mono-disciplinary perspective. This book shows how a multi-disciplinary approach may lead to new types of analysis and insights, contributing to a better understanding of the intricacies of transport pricing and eventually to a potentially more effective and acceptable design of such policies. The study addresses important policy and research themes such as the possible motives for introducing road transport pricing and potential conflicts between these motives, behavioural responses to transport pricing for households and firms, the modelling of transport pricing, and the acceptability of pricing.

Pipeline Landmark Detection for Autonomous Robot Navigation using Time-of-Flight Imagery

Scipedia content — Mon, 25 Jan 2021 11:57:25 +0100

3D imaging systems provide valuable information for autonomous robot navigation based on landmark detection in pipelines. This paper presents a method for using a time-of-flight (TOF) camera for detection and tracking of pipeline features such as junctions, bends and obstacles. Feature extraction is done by fitting a cylinder to images of the pipeline. Data in captured images appear to take a conic rather than cylindrical shape, and we adjust the geometric primitive accordingly. Pixels deviating from the estimated cylinder/cone fit are grouped into blobs. Blobs fulfilling constraints on shape and stability over time are then tracked. The usefulness of TOF imagery as a source for landmark detection and tracking in pipelines is evaluated by comparison to auxiliary measurements. Experiments using a model pipeline and a prototype robot show encouraging results. Pipeline Landmark Detection for Autonomous Robot Navigation using Time-of-Flight Imagery

Reinforcement Learning to Support Meta-Level Control in Air Traffic Management

Scipedia content — Mon, 25 Jan 2021 11:50:46 +0100

In a complex environment where the messages exchange intensively among the agents, a difficulty task is to decide the best action for new arriving messages during on-line control. A typical form of communication in Air Traffic Flow Management (ATFM) is verbal language to exchange the information and there is almost no digital recording of this communication between pilot and air controller. As the development of distributed computation system [1], the digital message communication is proposed especially for processing the immense amount of messages. In a real case such as the First Integrated Center of Air Defense and Air Traffic Control - CINDACTA I, in Brasilia, the system monitors 70% of the traffic flow in Brazil. According to the air traffic control procedure in CINDACTA I, Flight Information Region of Brasilia - FIR-BS is divided into 14 sectors and managed by 3 regional supervisors (Sao Paulo, Rio de Janeiro and Brasilia). Every air controller monitors his sector and is responsible to his supervisor. Only supervisor can make a decision to manage the air traffic flow. Any action is realized by air controller according to the decision of supervisor. For example, a decision may be to hold a flight in an airport for more 10 minutes, or assign the priority to another flight in the landing processing. In CINDACTA I, the monitor system (equipment and operation software) is suitable, but there is no a general system to manage and synchronize the traffic dynamically and to support the decision for adequate traffic management. Supervisor makes the decision just by his experience without quantity analyses of the impact of the action. To resolve this kind of problem, some researches were developed using the solution of Artificial Intelligence and others according to the new conception of ATFM. A distributed ATM system has been studied in Australia [2]. The advantages of that approach are inherent distribution, autonomy, communication and reliability. Prevot, from NASA Ames Research Center, has studied a distributed approach for operator interfaces and intelligent flight guidance, management and decision support [3]. An application of multi-agent coordination techniques in ATM, which sets up a methodological framework using multi-agent coordination techniques that supports the collaborative work in ATM has also been presented recently by Eurocontrol [4]. It should be mentioned that the multi-agen

Oil and Gas Pipeline Limited Charge Optimum Maintenance Decision-Making Analysis Based on Fuzzy-Gray-Element Theory and Fuzzy Analytical Hierarchy Process*

Scipedia content — Mon, 25 Jan 2021 11:46:21 +0100

This papers analyses the choice, combination and optimization of maintenance measures in the maintenance of oil and gas pipelines, initially proposes 4 factors system that influence effect of maintenance on pipelines, which includes person factor, fieldwork difficult degree, fieldwork management and environment condition, establishes hierarchy model of maintenance measures, introduces fuzzy analytical hierarchy process based on triangular fuzzy number, and compares the effects of different maintenance measures in order to determine the weight under single factor condition and composite matter-element of maintenance measures. On the basis of the above analysis, the paper proposes 4 methods of maintenance projects fund distribution based on different weight of efficiency factor of maintenance measures under the condition of limited charge. Using the fuzzy-gray-element theory combining fuzzy mathematics, gray theory and matter-element analysis, the paper analyses maintenance measure fund distribution based on different weight of efficiency factor of maintenance measures with fuzzy-gray-element correlation decision-making analysis, and conclusively determines optimization of maintenance project according to criteria of maximized correlative degree.

Exposing Memory Corruption and Finding Leaks: Advanced Mechanisms in Ada

Scipedia content — Mon, 25 Jan 2021 11:43:06 +0100

This article discusses the tools that Ada offers to deal with dynamic memory problems. The article shows how the storage pools mechanism of Ada 95 can be extended to enpower developers when tracking memory leaks and memory corruption in their code. This Ada extension rests on the notion of "checked pools", i.e. storage pools with an additional Dereference operation. The paper describes how a particular instance of the checked pool, called the "debug pool", is implemented in the GNAT technology. Performance measurements for the use of debug pools are provided in the context of the Air Traffic Flow Management application at Eurocontrol.

Knowledge Acquisition for the Creation of Assistance Tools to the Management of Air Traffic Control

Scipedia content — Mon, 25 Jan 2021 11:40:37 +0100

International audience; This paper presents an approach which has for objective to model new tools allowing to help the controllers to assume the incessant increase of the air traffic (actual version of the platform AMANDA V2), as well as help them in the negotiation phase and cooperation with their counterparts of adjacent sector (objectives of the new version of AMANDA). Help them in furnishing some tools able to quickly share information, and to maintain good common situation awareness. An approach is proposed, it is divided in three main phases. A first phase which consists of understand and to model the decision-making process of controllers. The second phase introduces a multiple criteria decision-making methodology. This Methodology has for objective to understand in more details the activities of controllers and the cases of cooperation with adjacent sectors. Finally, the last phase is the operational level of the approach, and consists of an application of repertory grid methodology in order to guide the interviews with the different participants of the study. This will allow realizing the knowledge acquisition, keeping in mind objective to develop new tools. To conclude this paper, the last part presents an example of application of this approach and the first results.

ITS-Based Transport Concepts and Location Preference: Will ITS Change ‘Business as Usual’?

Scipedia content — Mon, 25 Jan 2021 11:39:43 +0100

Intelligent Transportation Systems (ITS) are expected to solve problems regarding safety, congestion and environmental issues. Currently, automotive industries develop many applications, which are implemented in car driving, freight transportation and public transport. Our theory is based on the assumption that especially further integration of Advanced Driver Assistance Systems (ADAS) and travel based Information and Communication Systems (ICT) results in new and more attractive ITS concepts. These concepts will influence the performance of both passenger and goods transportation. Consequently, these integrated ITS concepts might in the long run influence the spatial dynamics and more specifically the development of firm locations. To test this hypothesis we use a systemic approach of scenario building. The construction and validation of these scenarios must result in both plausible and attractive images of future ITS. We need these images to conduct a survey and test our hypothesis. The scenarios will provide different futures of an urban region, with differences in accessibility and image of the transportation system. Besides the reaction of firms, we are also interested in responses of actors that develop locations, so-called suppliers. Both suppliers of and demanders for locations create our future space.

Sources of Air Pollution

Scipedia content — Mon, 25 Jan 2021 11:29:25 +0100

Publisher Summary National anthropogenic annual emission inventories can, on their own, give a misleading picture regarding the appropriate sources to control. What is important for most pollutants are those sources that make major contributions to elevated concentrations during pollution episodes. As most people live in cities, urban inventories are important for identifying these sources. The main source of air pollution is the burning of fossil fuels, particularly in power stations and motor vehicles. Emissions from both these sources have begun to decline in recent years owing to the introduction of efficient abatement measures. In most urban areas, road transport is the dominant source of pollution as measures to reduce wintertime smogs in earlier decades lead to the re-location of many large stationary sources to rural or semi-rural sites. Road transport is the single most important source of most of the classical air pollutants. The exceptions are sulfur dioxide and volatile organic compounds. To develop effective control strategies for reducing urban emissions, it is important to know which type of vehicles are contributing most to the total road traffic emissions. It is not possible to measure emissions from every single one. Instead, emissions are generally calculated from a measure of activity relating to the emissions, such as fuel consumption for stationary sources and distance traveled for mobile sources. Emission factors, derived from measurements of individual or representative sources, are then multiplied by the appropriate statistic to give the emission rate.

Network emulation focusing on QoS-Oriented satellite communication

Scipedia content — Mon, 25 Jan 2021 11:21:36 +0100

This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication.

The London Experience

Scipedia content — Mon, 25 Jan 2021 11:14:16 +0100

The Stockholm Congestion Charging System: A Summary of the Effects

Scipedia content — Mon, 25 Jan 2021 11:02:08 +0100

This paper draws upon the summary report written by the expert evaluation group, chaired by the author of this summary. The Stockholm trial consisted of two parts: a congestion charging scheme that was in place between 3 Jan and 31 July 2006, and extended public transport that was in place between 31 August 2005 and 31 December 2006. Initially, the trial was meant to consist only of a congestion charging scheme. Later, it was decided that the charging scheme should be complemented by public transit extensions â several new bus lines, additional capacity on commuter trains and subways, and more park-and-ride facilities. The congestion charging scheme was originally meant to be a âfull-scale trial for several yearsâ, and was a part of an agreement between the Social Democrats, Lefts and Green on the national level following the election in the autumn of 2002. For various reasons â most importantly legal complaints regarding the technology procurement process - the period with congestion charges became considerably shorter than was initially planned. The Stockholm trial was followed by referendums in the City of Stockholm and in about half of the neighboring municipalities. The referendum in the City of Stockholm ended with a majority for keeping the charges, but adding all votes up, a majority of the voters in the county were against the charges. However, the results could be viewed as a bit skewed, since most of the municipalities where polls showed greater support for the charges did not arrange a referendum at all. After pondering how to interpret the outcome of the referendums for a few weeks, the new national government decided that congestion charges should be reintroduced in August 2007. At the time of writing, a negotiator appointed by the national government is trying to strike a deal between the municipalities and the county of Stockholm. The deal is meant to produce a âpackageâ where the charge revenues is used for number of road investments â possibly also including additional government funding, but that is not clear currently.

Acceptability of Road Pricing

Scipedia content — Mon, 25 Jan 2021 10:46:07 +0100

Optimal Toll Design Problem: A Dynamic Network Modelling Approach

Scipedia content — Mon, 25 Jan 2021 10:39:05 +0100

A Multi-disciplinary View

Scipedia content — Mon, 25 Jan 2021 10:31:42 +0100

Achieving Fast BGP Reroute with Traffic Engineering Using Multiple Routing Planes

Scipedia content — Mon, 25 Jan 2021 10:30:36 +0100

In today's BGP routing architecture, traffic delivery is in general based on single path selection paradigms. The lack of path diversity hinders the support for resilience, traffic engineering and QoS provisioning across the Internet. Some recently proposed multi-plane extensions to BGP offer a promising mechanism to enable diverse inter-domain routes towards destination prefixes. Based on these enhanced BGP protocols, we propose in this paper a novel technique to enable controlled fast egress router switching for handling network failures. In order to minimize the disruptions to real-time services caused by the failures, backup egress routers can be immediately activated through locally remarking affected traffic towards alternative routing planes without waiting for IGP routing re-convergence. According to our evaluation results, the proposed multi-plane based egress router selection algorithm is able to provide both high path diversity and balanced load distribution across inter-domain links with a small number of planes.

Travellers’ Responses to Road Pricing: Value of Time, Schedule Delay and Unreliability

Scipedia content — Mon, 25 Jan 2021 10:28:25 +0100

A New Precomputation Scheme for MPLS Traffic Engineering Routing

Scipedia content — Mon, 25 Jan 2021 10:25:52 +0100

This paper presents a new precomputation algorithm for Multi Protocol Label Switching (MPLS) traffic engineering routing. The prior MPLS routing algorithms try to minimize the interference between different source-destination pairs by circumventing the critical links. But the process of identifying critical links is very computationally expensive. The main contribution of this paper is a new precomputation approach of route selection considering the interference. The proposed algorithm reduces online computing complexity through efficient precomputation. From the simulation results, the proposed algorithm outperforms prior algorithms in terms of efficiency and complexity.

Failure Probability Estimation of Long Pipeline

Scipedia content — Thu, 21 Jan 2021 15:32:08 +0100

It is well known that, for the majority of pressurized pipelines, both the load and the resistance parameters show evident uncertainty, and a probabilistic approach should be applied to assess their behaviors. Concerning reliability estimation of passive components such as pressure vessel and pipeline, there are two kinds of approaches â direct estimation using statistics of historical failure event data, and indirect estimation using probabilistic analysis of the failure phenomena of consideration. The direct estimation method can be validated relatively easily. However, it suffers statistical uncertainty due to scarce data. Indirect estimation method relies on the statistics of material property and those of environment load which are more readily available. As to systems composed of passive components, statistical dependence among component failures is a complex issue that cannot be ignored in reliability estimation.

Provision of real-time traffic information of VRPTW model

Scipedia content — Thu, 21 Jan 2021 15:28:37 +0100

The Minimal Buffering Requirements of Congestion Controlled Interactive Multimedia Applications

Scipedia content — Thu, 21 Jan 2021 15:25:55 +0100

This paper uses analysis and experiments to study the minimal buffering requirements of congestion controlled multimedia applications. Applications in the Internet must use congestion control protocols, which vary transmission rates according to network conditions. To produce a smooth perceptual quality, multimedia applications use buffering and rate adaptations to compensate these rate oscillations. While several adaptation policies are available, they require different amounts of buffering at end-hosts. We study the relationship between buffering requirements and adaptation policies. In particular, we focus on a widely pursued policy that adapts an application's sending rate exactly to the average available bandwidth to maximize throughput. Under this adaptation policy, at least a minimal amount of buffering is required to smooth the rate oscillation inherent in congestion control, and we view this minimal buffering requirement as a cost of maximizing throughput. We derive the minimal buffering requirement for this policy assuming that applications use an additive-increase-and-multiplicative-decrease (AIMD) algorithm for congestion control. The result shows the relationship between parameters of AIMD algorithms and the delay cost. We show that the buffering requirement is proportional to the parameters of the AIMD algorithm and quadratic to the application's sending rate and round-trip-time. We verify this relationship through experiments. Our results indicate that adaptation policies that maximize throughput are not suitable for interactive applications with high bit rates or long round-trip-times.

Using Risk Analysis to Evaluate Design Alternatives

Scipedia content — Thu, 21 Jan 2021 15:25:43 +0100

Recently, multi-agent systems have proved to be a suitable approach to the development of real-life information systems. In particular, they are used in the domain of safety critical systems where availability and reliability are crucial. For these systems, the ability to mitigate risk (e.g., failures, exceptional events) is very important. In this paper, we propose to incorporate risk concerns into the process of a multi-agent system design and describe the process of exploring and evaluating design alternatives based on risk-related metrics. We illustrate the proposed approach using an Air Traffic Management case study.

Integrating Model Checking and HCI Tools to Help Designers Verify User Interface Properties

Scipedia content — Thu, 21 Jan 2021 14:56:17 +0100

In this paper we present a method that aims to integrate the use of formal techniques in the design process of interactive applications, with particular attention to those applications where both usability and safety are main concerns. The method is supported by a set of tools. We will also discuss how the resulting environment can be helpful in reasoning about multi-user interactions using the task model of an interactive application. Examples are provided from a case study in the field of air traffic control.

Behavioural Responses of Freight Transporters and Shippers to Road-User Charging Schemes: An Empirical Assessment

Scipedia content — Thu, 21 Jan 2021 14:52:32 +0100

Were British railway companies well-managed in the early twentieth century?

Scipedia content — Thu, 21 Jan 2021 14:35:55 +0100

This is a revised version of a previous working paper, of the same name, which incorporates corrections to errors in our estimates of TFP growth. This paper examines major privately-owned British railway companies before World War I. Quantitative evidence is presented on return on capital employed, total factor productivity growth, cost inefficiency, and speed of passenger services. There were discrepancies in performance across companies but ROCE and TFP typically fell during our period. Cost inefficiency rose before 1900 but then was brought under control as a profits collapse loomed. Without the discipline of either strong competition or effective regulation, managerial failure was common. This sector is an important qualification to the conventional wisdom that late-Victorian Britain did not fail.

Entrance channels and alpha decay half-lives of the heaviest elements

Scipedia content — Thu, 21 Jan 2021 14:25:54 +0100

Ouvrage concluant une Action de Concertation Incitative "Espace et territoires": La construction nationale palestinienne entre formation de l'Etat et vie diasporique; This chapter analyzes the legal status granted by the United Nations and the Arab hot states to the refugees in the Near and the Middle East. It first identifies the various geopolitical, security and economic factors that underpinned the creation and the evolution of that status since 1948, and goes on examining more precisely their impact on the Palestinian nation-building process. In so doing, it shows how, under the pressure of the refugees and their representatives, the legal status has been turned into a prop for that process, even though the various political and socioeconomic discriminations it has generated have affected the refugees' human security in the host countries. Forsaken for decades, the issue of the Palestinian refugees' permanent status, and with it the destiny of the host societies, have resurfaced following the failure of the peace process (failure of the Camp David Summit) and the outbreak of the Intifada in 2000.; Ce chapitre d'ouvrage analyse le statut juridique confÃ©rÃ© par les Nations Unies et les pays arabes d'accueil aux rÃ©fugiÃ©s palestinien. Il examine d'abord les intÃ©rÃªts d'ordre gÃ©opolitique, sÃ©curitaire et Ã©conomique qui ont influÃ© sur la crÃ©ation et l'Ã©volution de ce statut depuis 1948, puis il examine plus prÃ©cisÃ©ment son impact sur la construction nationale palestinienne. ll montre Ã cet Ã©gard comment, sous la pression des rÃ©fugiÃ©s et de leurs reprÃ©sentants, le statut juridique s'est transformÃ©, Ã dessein ou par dÃ©faut, en un soutien Ã cette construction, mÃªme si les discriminations d'ordre politique et socioÃ©conomique qu'il a engendrÃ©es ont dans le mÃªme temps contribuÃ© Ã la dÃ©tÃ©rioration de la sÃ©curitÃ© humanitaire des rÃ©fugiÃ©s dans les pays d'accueil. IgnorÃ©e pendant plusieurs dÃ©cennies, la question du statut permanent des rÃ©fugiÃ©s a pris un certain relief suite Ã la suspension du processus de paix israÃ©lo-palestinien (Ã©chec sommet de Camp David) et du dÃ©clenchement de l'Intifada en 2000. C'est alors aussi le destin des sociÃ©tÃ©s d'accueil qui s'est posÃ© avec acuitÃ©.

Development and Utilization of Parallel Generic Algorithms for Scientific Computations

Scipedia content — Thu, 21 Jan 2021 14:22:15 +0100

We develop generic parallel algorithms as extensible modules that encapsulate related classes and parallel methods. Extensible modules define common parallel structures, such as meshes, pipelines, or master-server networks in problem-independent manner. Such modules can be extended with sequential domain-specific code in order to derive particular parallel applications.

Spatial Planning for a Sustainable Singapore

Scipedia content — Thu, 21 Jan 2021 13:26:05 +0100

The book is intended to be a landmark publication to showcase Singapore academics' and practising planners'work and thinking in the globalisation age. The book takes a reflective approach in reviewing the direction, impact and signifiance of sustainable development in Singapore planning and the future challenges facing the city-state looked upon by many developing countries as a model. The book analyses and provides an insight to Singapore's planning system and practices associated with sustainable development. It contributes and produces an impact on urban planning literature in a renewed perspective about Singapore that reflects the reality and need to address sustainability in the triangular relation ship of economic, environmental and social developmen

The Fairness Challenge in Computer Networks

Scipedia content — Thu, 21 Jan 2021 13:08:58 +0100

In this paper, the concept of fairness as a future field of research in computer networks is investigated. We motivate the need of examining fairness issues by providing example future application scenarios where fairness support is needed in order to experience sufficient service quality. We further demonstrate how fairness definitions from political science and in computer networks are related and, finally, contribute with this work to the ongoing research activities by defining the fairness challenge with the purpose of helping direct future investigations to the white spots on the map of research in fairness.

Proportional Service Differentiation with MPLS

Scipedia content — Thu, 21 Jan 2021 13:03:07 +0100

This paper describes two traffic engineering techniques for implementing proportional differentiated services based on Multiprotocol Label Switching constraint based routing. Both use a dynamic bandwidth allocation scheme to modify the bandwidth reserved by each traffic class according to the current network load. The first scheme uses an adaptive algorithm that qualitatively determines the required average throughput per source for each class and moves bandwidth between classes for each path as necessary. The second scheme mathematically divides the existing bandwidth through the traffic classes for each path. The quality of service that users get with both techniques is assessed by simulation and compared with a fixed bandwidth allocation scheme.

Remaining sites verification package for the 100 f 26 10 1607 f3 sanitary sewer pipelines 182 f 183 f and 151 f sanitary sewer lines waste site reclassification form 2007 028

Scipedia content — Mon, 26 Oct 2020 13:41:15 +0100

The 100-F-26:10 waste site includes sanitary sewer lines that serviced the former 182-F, 183-F, and 151-F Buildings. In accordance with this evaluation, the verification sampling results support a reclassification of this site to Interim Closed Out. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

Document type: Report

Scoping study on the safety impact of valve spacing in natural gas pipelines

Scipedia content — Mon, 26 Oct 2020 13:40:10 +0100

The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) is responsible for ensuring the safe, reliable, and environmentally sound operation of the nation's natural gas and hazardous liquid pipelines. Regulations adopted by PHMSA for gas pipelines are provided in 49 CFR 192, and spacing requirements for valves in gas transmission pipelines are presented in 49 CFR 192.179. The present report describes the findings of a scoping study conducted by Oak Ridge National Laboratory (ORNL) to assist PHMSA in assessing the safety impact of system valve spacing. Calculations of the pressures, temperatures, and flow velocities during a set of representative pipe depressurization transients were carried out using a one-dimensional numerical model with either ideal gas or real gas properties for the fluid. With both ideal gas and real gas properties, the high-consequence area radius for any resulting fire as defined by Stevens in GRI-00/0189 was evaluated as one measure of the pipeline safety. In the real gas case, a model for convective heat transfer from the pipe wall is included to assess the potential for shut-off valve failures due to excessively low temperatures resulting from depressurization cooling of the pipe. A discussion is also provided of some additionalmoreÂ Â» factors by which system valve spacing could affect overall pipeline safety. The following conclusions can be drawn from this work: (1) Using an adaptation of the Stephens hazard radius criteria, valve spacing has a negligible influence on natural gas pipeline safety for the pipeline diameter, pressure range, and valve spacings considered in this study. (2) Over the first 30 s of the transient, pipeline pressure has a far greater effect on the hazard radius calculated with the Stephens criteria than any variations in the transient flow decay profile and the average discharge rate. (3) Other factors besides the Stephens criteria, such as the longer burn time for an accidental fire, greater period of danger to emergency personnel, increased unavoidable loss of gas, and possible depressurization cooling of the shut-off valves may also be important when deciding whether a change in the required valve spacing would be beneficial from a safety standpoint. (4) The average normalized discharge rate of {lambda}{sub avg} = 0.33 assumed by Stephens in developing his safety criteria is an excellent conservative value for natural gas discharge at the pressures, valve spacings, and pipe diameter used in this study. This conclusion remains valid even when real rather than ideal gas properties are considered in the analysis. (5) Significant pipe wall cooling effects (T{sub w} " -50 F or 228 K) can extend for a mile or more upstream from the rupture point within 30 s of a break. These conditions are colder than the temperature range specifications for many valve lubricants. The length of the low-temperature zone due to this cooling effect is also essentially independent of the system shut-off valve spacing or the distance between the break and a compressor station. (6) Having more redundant shut-off valves available would reduce the probability that pipe cooling effects could interfere with isolating the broken area following a pipeline rupture accident.Â«Â le

Document type: Report

Natural gas pipeline technology overview

Scipedia content — Mon, 26 Oct 2020 13:38:15 +0100

The United States relies on natural gas for one-quarter of its energy needs. In 2001 alone, the nation consumed 21.5 trillion cubic feet of natural gas. A large portion of natural gas pipeline capacity within the United States is directed from major production areas in Texas and Louisiana, Wyoming, and other states to markets in the western, eastern, and midwestern regions of the country. In the past 10 years, increasing levels of gas from Canada have also been brought into these markets (EIA 2007). The United States has several major natural gas production basins and an extensive natural gas pipeline network, with almost 95% of U.S. natural gas imports coming from Canada. At present, the gas pipeline infrastructure is more developed between Canada and the United States than between Mexico and the United States. Gas flows from Canada to the United States through several major pipelines feeding U.S. markets in the Midwest, Northeast, Pacific Northwest, and California. Some key examples are the Alliance Pipeline, the Northern Border Pipeline, the Maritimes & Northeast Pipeline, the TransCanada Pipeline System, and Westcoast Energy pipelines. Major connections join Texas and northeastern Mexico, with additional connections to Arizona and between California and Baja California, MexicomoreÂ Â» (INGAA 2007). Of the natural gas consumed in the United States, 85% is produced domestically. Figure 1.1-1 shows the complex North American natural gas network. The pipeline transmission system--the 'interstate highway' for natural gas--consists of 180,000 miles of high-strength steel pipe varying in diameter, normally between 30 and 36 inches in diameter. The primary function of the transmission pipeline company is to move huge amounts of natural gas thousands of miles from producing regions to local natural gas utility delivery points. These delivery points, called 'city gate stations', are usually owned by distribution companies, although some are owned by transmission companies. Compressor stations at required distances boost the pressure that is lost through friction as the gas moves through the steel pipes (EPA 2000). The natural gas system is generally described in terms of production, processing and purification, transmission and storage, and distribution (NaturalGas.org 2004b). Figure 1.1-2 shows a schematic of the system through transmission. This report focuses on the transmission pipeline, compressor stations, and city gates.Â«Â le

Document type: Report

Analysis of co2 separation from flue gas pipeline transportation and sequestration in coal

Scipedia content — Mon, 26 Oct 2020 13:36:14 +0100

This report was written to satisfy a milestone of the Enhanced Coal Bed Methane Recovery and CO2 Sequestration task of the Big Sky Carbon Sequestration project. The report begins to assess the costs associated with separating the CO2 from flue gas and then injecting it into an unminable coal seam. The technical challenges and costs associated with CO2 separation from flue gas and transportation of the separated CO2 from the point source to an appropriate sequestration target was analyzed. The report includes the selection of a specific coal-fired power plant for the application of CO2 separation technology. An appropriate CO2 separation technology was identified from existing commercial technologies. The report also includes a process design for the chosen technology tailored to the selected power plant that used to obtain accurate costs of separating the CO2 from the flue gas. In addition, an analysis of the costs for compression and transportation of the CO2 from the point-source to an appropriate coal bed sequestration site was included in the report.

Document type: Report

Pipeline removal versus characterization study

Scipedia content — Mon, 26 Oct 2020 12:29:03 +0100

Document type: Report

Social and Economic Conditions of Student Life in Europe: Synopsis of indicators - Final Report - Eurostudent III 2005-2008

Scipedia content — Mon, 26 Oct 2020 12:22:24 +0100

The EUROSTUDENT report is based on a unique dataset covering more than 120,000 students in 23 European countries. The surveyed students provided information on the social and economic conditions of their life. In essence, the EUROSTUDENT dataset describes a biography from entrance into a higher education system, to study conditions during studies, and finally to exit from the higher education system. Additionally, it covers temporary international mobility. The analysis offers the chance to review common practices and their effectiveness in the light of European trends and with the insight that alternatives are possible and, in some cases, actually being practiced by neighbouring countries.

Document type: External research report

Performance evaluation of expert team members

Scipedia content — Mon, 26 Oct 2020 12:16:19 +0100

Abstract : We found that CWS can do a reasonable job of capturing expertise in arithmetic compared to indices that incorporate correct answers. We also found (in conjunction with Rick Thomas and Alex Kirlik) similar results for a performance domain, putting a golf ball. In addition, we initiated the development of designs that allow the extraction of individual performance from team scores. We used the CTEAM simulation to study the development of expertise of teams of simulated air traffic controllers. CWS served as the primary index of performance, although traditional measures were examined as well. As a performance measure, CWS (based on time through sector) was observed to be more sensitive to improvement over practice than operational errors. Experts make too few errors to provide differential accuracy information, while CWS attends to aspects of performance that can always be observed, whether errors are made or not.

Document type: Report

Hwma rcra closure plan for the fluorinel dissolution process makeup and cooling and heating systems voluntary consent order site tank 005 action plan tank systems intec 066 intec 067 intec 068 and intec 072

Scipedia content — Mon, 26 Oct 2020 11:23:30 +0100

This Hazardous Waste Management Act/Resource Conservation and Recovery Act closure plan for the fluorinel dissolution process makeup and cooling and heating systems located in the Fluorinel Dissolution Process and Fuel Storage Facility (CPP-666), Idaho Nuclear Technology and Engineering Center, Idaho National Laboratory Site, was developed to meet milestones established under the Voluntary Consent Order. The systems to be closed include waste piping associated with the fluorinel dissolution process makeup systems. This closure plan presents the closure performance standards and methods of achieving those standards.

Document type: Report

Remaining sites verification package for the 1607 b1 septic system waste site reclassification form 2007 015

Scipedia content — Mon, 26 Oct 2020 11:21:30 +0100

The 1607-B1 Septic System includes a septic tank, drain field, and associated connecting pipelines and influent sanitary sewer lines. This septic system serviced the former 1701-B Badgehouse, 1720-B Patrol Building/Change Room, and the 1709-B Fire Headquarters. The 1607-B1 waste site received unknown amounts of nonhazardous, nonradioactive sanitary sewage from these facilities during its operational history from 1944 to approximately 1970. In accordance with this evaluation, the confirmatory sampling results support a reclassification of this site to No Action. The current site conditions achieve the remedial action objectives and the corresponding remedial action goals established in the Remaining Sites ROD. The results of confirmatory sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

Document type: Report

Remaining sites verification package for the 1607 f3 sanitary sewer system waste site reclassification form 2006 047

Scipedia content — Mon, 26 Oct 2020 10:13:22 +0100

The 1607-F3 waste site is the former location of the sanitary sewer system that supported the 182-F Pump Station, the 183-F Water Treatment Plant, and the 151-F Substation. The sanitary sewer system included a septic tank, drain field, and associated pipeline, all in use between 1944 and 1965. In accordance with this evaluation, the verification sampling results support a reclassification of this site to Interim Closed Out. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

Document type: Report

Engineering evaluation of nitrogen purge fill station

Scipedia content — Mon, 26 Oct 2020 10:12:24 +0100

This document is a Engineering/Tools Evaluates for tools used to fill the Cross-Site transfer line encasements with nitrogen.

Document type: Report

Research and development of an integral separator for a centrifugal gas processing facility

Scipedia content — Thu, 22 Oct 2020 16:10:11 +0200

A COMPACT GAS PROCESSING DEVICE WAS INVESTIGATED TO INCREASE GAS PRODUCTION FROM REMOTE, PREVIOUSLY UN-ECONOMIC RESOURCES. THE UNIT WAS TESTED ON AIR AND WATER AND WITH NATURAL GAS AND LIQUID. RESULTS ARE REPORTED WITH RECOMMENDATIONS FOR FUTURE WORK.

Document type: Report

Estimation of the temperature rise of a mcu acid stream pipe in near proximity to a sludge stream pipe

Scipedia content — Thu, 22 Oct 2020 15:36:26 +0200

Effluent streams from the Modular Caustic-Side Solvent Extraction Unit (MCU) will transfer to the tank farms and to the Defense Waste Processing Facility (DWPF). These streams will contain entrained solvent. A significant portion of the Strip Effluent (SE) pipeline (i.e., acid stream containing Isopar{reg_sign} L residues) length is within one inch of a sludge stream. Personnel envisioned the sludge stream temperature may reach 100 C during operation. The nearby SE stream may receive heat from the sludge stream and reach temperatures that may lead to flammability issues once the contents of the SE stream discharge into a larger reservoir. To this end, personnel used correlations from the literature to estimate the maximum temperature rise the SE stream may experience if the nearby sludge stream reaches boiling temperature. Several calculation methods were used to determine the temperature rise of the SE stream. One method considered a heat balance equation under steady state that employed correlation functions to estimate heat transfer rate. This method showed the maximum temperature of the acid stream (SE) may exceed 45 C when the nearby sludge stream is 80 C or higher. A second method used an effectiveness calculation used to predict the heat transfer rate in more » single pass heat exchanger. By envisioning the acid and sludge pipes as a parallel flow pipe-to-pipe heat exchanger, this method provides a conservative estimation of the maximum temperature rise. Assuming the contact area (i.e., the area over which the heat transfer occurs) is the whole pipe area, the results found by this method nearly matched the results found with the previous calculation method. It is recommended that the sludge stream be maintained below 80 C to minimize a flammable vapor hazard from occurring. « le

Document type: Report

Congestion control in a reliable scalable message oriented middleware

Scipedia content — Wed, 14 Oct 2020 16:33:16 +0200

This paper presents congestion control mechanisms for reliable and scalable message-oriented middleware following the publish/subscribe communication model. We identify the key requirements of congestion control in this environment, how it differs from congestion control for the Internet, and propose a combination of two congestion control mechanisms, (1) driven by a publisher hosting broker (PDCC), (2) driven by a subscriber hosting broker (SDCC). SDCC decouples the notion of a receive window and a NACK window, and is used by subscriber hosting brokers in recovery mode. PDCC implements a scalable and low latency feedback loop between a publisher hosting broker and all subscriber hosting brokers, which is used to adjust the rate of publishing new messages, to allow brokers in recovery to eventually catch up, and other brokers to keep up. We present a detailed experimental evaluation of our implementation of these mechanisms in the Gryphon system by injecting network failures and link congestion.