Documents published in 2010 : Scipedia

An evolutionary approach to pickup and delivery problem with time windows
J. Créput, A. Koukam, J. Kozlak, J. Lukasik

Collection of open chapters of books in transport research (2010). Vol. 2010, 62

Abstract
Recently, the quality and the diversity of transport services are more and more required. Moreover, in case of a great deal of services and selling goods, a significant part of price is transport cost. Thus, the design of models and applications which make possible efficient transport planning and scheduling becomes important. A great deal of real transport problems may be modelled by using Pickup and Delivery Problem with Time Windows (PDPTW) and capacity constraints, which is based on the realization of a set of transport requests by a fleet of vehicles with given capacities. Each request is described by pickup and delivery locations, time periods when pickup and delivery operations should be performed and needed load. Application of evolutionary approach has brought good results in case of another, simpler transport problem the Vehicle Routing Problem with Time Windows (VRPTW). This paper is aimed at proposing a straightforward extension of VRPTW based heuristics for the PDPTW. Document type: Part of book or chapter of book
Abstract
Recently, the quality and the diversity of transport services are more and more required. Moreover, in case of a great deal of services and selling goods, a significant part [...]
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Experimental analysis of the sabul congestion control algorithm
P. Oothongsap, Y. Viniotis, M. Vouk

Collection of open chapters of books in transport research (2010). Vol. 2010, 61

Abstract
Several new protocols such as RBUDP, User-Level UDP, Tsunami, and SABUL, have been proposed as alternatives to TCP for high-speed data transfer. The purpose of this paper is to analyze experimentally the effects of SABUL congeston control algorithm on SABUL and performance metrics such as bandwidth utilization, self-fairness, and aggressiveness. Our results confirm some expected behavior of SABUL and reveal some less expected one. Our experiments also indicate that SABUL implementation and design can result in an even more erratic behavior and degraded performance under high-congestion conditions. Document type: Part of book or chapter of book
Abstract
Several new protocols such as RBUDP, User-Level UDP, Tsunami, and SABUL, have been proposed as alternatives to TCP for high-speed data transfer. The purpose of this paper [...]
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Vom Planungsleitbild "Durchmischte Stadt" zu den Auswirkungen auf Alltagsmobilität am Beispiel der Hamburger Elbinseln
K. Stock

Collection of open chapters of books in transport research (2011). Vol. 2011, 89

Abstract
Die "durchmischte" Stadt als Leitbild aktueller Stadtentwicklung wird im Kontext aktueller planerischer Diskussionen dargestellt und der Aspekt der Förderung der Alltagsmobilität wird als beispielhafter Indikator nachhaltiger sozial gerechter Entwicklung untersucht. Die Bedeutung und die Möglichkeiten planerischer Einflussnahme auf Alltagsmobilität sind Gegenstand grundsätzlicher Überlegungen, die darauf folgend am Beispiel der Elbinsel Wilhelmsburg vertieft werden. Beispielhaft erfolgt die Untersuchung des Hamburger Vorhabens "Sprung über die Elbe", speziell dessen Umsetzung in Form der Internationalen Bauausstellung IBA Hamburg als Beispiel für einen aktuellen, dem Leitbild der durchmischten Stadt folgendem, Stadtentwicklungsprozess. Hier wird der Frage nachgegangen, inwieweit die bestehenden Strukturen und die Bedürfnisse der ansässigen Bevölkerung berücksichtigt werden und eine Verbesserung der Alltagsmobilität als Instrument ihrer Förderung eingesetzt wird. Die Untersuchung will einen Überblick über die eingesetzten Maßnahmen schaffen und aufzeigen, welche zu einer gerechten Planung beitragen und für eine ausgleichende Verteilung von Chancen in Form einer für alle zugänglichen Alltagsmobilität in der Metropole sorgen. Es erfolgt keine Untersuchung von Verkehrsstatistiken und -zahlen, sondern von Planungszielen, Projektvorhaben und erzielten Ergebnissen. Abschließend wird deutlich, dass Elemente zur Fortentwicklung der Alltagsmobilität in einzelnen Projektvorhaben gefunden werden, aber keine übergreifende Untersuchung oder kein Maßnahmenplan zur Verbesserung vorliegt und eine Diskussion entweder im Detail oder auf abstrakter Ebene geführt wird. This article describes the "city of mixed functions" as a general principle of contemporary urban development against the background of the present discourse on urban planning. Based on this it looks into the advancement of everyday mobility as an exemplary indicator for social sustainable and equitable development. The meaning of everyday mobility and the possibilities of influencing it through urban planning are subjects of fundamental considerations. In the following part they are proved by using the example Wilhelmsburg, a quarter of the city of Hamburg. The local analysis starts with the research of Hamburg's political development concept titled "Sprung über die Elbe" ("Leap over the Elbe-river"). In detail there will be a look on one part of its spatial realization found in the project of the international building exhibition IBA Hamburg. This is an instance of contemporary urban planning under the guiding principle of the aforementioned "city of mixed functions". Following up the question how far the existing structures and the needs of the residents are allowed for and whether an improvement of everyday mobility is introduced as an instrument for their advancement, the research aims to provide an overview of the implemented measures, which contribute to equitable urban planning and social equity in the form of universally accessible everyday mobility in the metropolitan area of Hamburg. This does not include specific statistics and numbers related to transportation, but instead an analysis of the goals of urban planning, the intended projects, and the obtained results. Finally it becomes apparent that elements for the development of everyday mobility can be found in the individual intended projects. However, there exists no overarching investigation or strategy plan for everyday mobility. The existing discussion is hold either on an abstract level or in practical project details. Document type: Book
Abstract
Die "durchmischte" Stadt als Leitbild aktueller Stadtentwicklung wird im Kontext aktueller planerischer Diskussionen dargestellt und der Aspekt der Förderung der Alltagsmobilität [...]
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Paging load congestion control in cellular mobile networks
I. Koukoutsidis

Collection of open chapters of books in transport research (2010). Vol. 2010, 60

Abstract
This paper addresses the requirement for a congestion control mechanism, in order to efficiently handle paging traffic over cellular networks. The standard simultaneous paging approach can easily result in congestion, for relatively small values of the offered load. Instead of differentiating paging capacity based on the incoming load, this approach is more oriented towards a limited-resource system. Considering that a paging channel usually experiences high and low utilization periods, it is proposed to differentiate the paging mechanism according to the processed load. Given medium or even mild overload conditions, several forms of sequential paging substantially decrease blocking probabilities, while presenting good delay behavior. Based on a queueing analysis, we are able to quantitatively estimate potential improvements, and point out the basic points of such an adaptive scheme. Document type: Part of book or chapter of book
Abstract
This paper addresses the requirement for a congestion control mechanism, in order to efficiently handle paging traffic over cellular networks. The standard simultaneous paging [...]
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The Use of Computers for Controlling Electricity Flows in Sweden, 19501980
A. Kaijser

Collection of open chapters of books in transport research (2010). Vol. 2010, 59

Abstract
Part 2: Computerizing Public Sector Industries International audience An important application of computers from the 1950s and onwards has been for designing and operating complex infrastructural systems like air traffic, telephony, railways, and electricity. This paper tells the story about how computers from the 1950s and onwards became an important tool for designing and operating the Swedish power grid. It describes two phases of this development. In the 1950s and 1960s, computers were used for making complicated calculations for designing power grids in a reliable way and optimizing the use of the different power plants. In a second phase starting in the late 1960s, computer systems were developed for real time monitoring supporting human control of the power grid. The paper analyzes by whom and for what purposes computers became tools for controlling electricity flows. In the conclusion, it also discusses the wider implications of computers for the development of the Swedish power system. Document type: Part of book or chapter of book
Abstract
Part 2: Computerizing Public Sector Industries International audience An important application of computers from the 1950s and onwards has been for designing and operating [...]
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Reliable and Restricted Quickest Path Problems
S. Ruzika, M. Thiemann

Collection of open chapters of books in transport research (2011). Vol. 2011, 87

Abstract
In a dynamic network, the quickest path problem asks for a path minimizing the time needed to send a given amount of flow from source to sink along this path. In practical settings, for example in evacuation or transportation planning, the reliability of network arcs depends on the specific scenario of interest. In this circumstance, the question of finding a quickest path among all those having at least a desired path reliability arises. In this article, this reliable quickest path problem is solved by transforming it to the restricted quickest path problem. In the latter, each arc is associated a nonnegative cost value and the goal is to find a quickest path among those not exceeding a predefined budget with respect to the overall (additive) cost value. For both, the restricted and reliable quickest path problem, pseudopolynomial exact algorithms and fully polynomial-time approximation schemes are proposed. Document type: Part of book or chapter of book
Abstract
In a dynamic network, the quickest path problem asks for a path minimizing the time needed to send a given amount of flow from source to sink along this path. In practical [...]
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Infrastrukturentwicklung im europäischen Korridor Rotterdam-Genua: das INTERREG-IV-B-Projekt "Code 24"
C. Scheck, S. Wilske

Collection of open chapters of books in transport research (2011). Vol. 2011, 85

Abstract
Die in den letzten Jahren stetig wachsende Mobilität wirkt sich auf die Entwicklung von Wirtschaft, Umwelt und Raum aus. Dabei treten neue Spannungsfelder zwischen Verkehrs- und Siedlungsentwicklung, aber auch zwischen Wirtschaft und Umwelt auf. Besonders große Verkehrszuwächse werden für den multimodalen Korridor Nr. 24 im Transeuropäischen Verkehrsnetz der Europäischen Union (TEN-V) zwischen Rotterdam und Genua prognostiziert. Der vorliegende Beitrag behandelt das INTERREG-IVB-Projekt "CODE 24", welches mit dem Aufbau eines Policy-Netzwerks die Korridorentwicklung mittels einer integrierten Betrachtungsweise im Sinne der Nachhaltigkeit vorantreiben möchte. Neben den Arbeitspaketen des Projekts zur Raumplanung und Infrastrukturentwicklung, zu Güterverkehr und Logistik sowie zur Kommunikation und Akzeptanz wird vertieft die Maßnahme "Planungsleitfaden für innovative Lärmschutzsysteme" dargestellt. Darin sollen unterschiedliche Lärmschutzsysteme systematisch analysiert werden und ein "Auralisationstool" zum Einsatz kommen, mit dem bereits in der Planungsphase die akustischen Auswirkungen der diskutierten Alternativen hörbar gemacht werden können. The growing mobility of the last years influences the development of economy, environment and space. In this context there are new areas of conflict both between transport and settlement development and between economy and environment. Extra high increases are expected in the multi-modal corridor No. 24 of the Trans-European Transport Network (TEN-T) between Rotterdam and Genua. The present article reflects the INTERREG-IVB-project "CODE 24", which wants to promote the corridor development sustainably with an integrated view. Beside the work packages of the project about spatial and infrastructural development, about freight transport and logistics and about communication and acceptance the action "planners' toolbox for innovative noise protection" is presented in detail. In this action several systems for noise protection will be systematically analysed and an "auralisation tool" will be used, with which the acoustic effects of discussed alternatives can be made audible already in the planning process. Document type: Book
Abstract
Die in den letzten Jahren stetig wachsende Mobilität wirkt sich auf die Entwicklung von Wirtschaft, Umwelt und Raum aus. Dabei treten neue Spannungsfelder zwischen Verkehrs- [...]
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The SYNCROMAX Solution for Air Traffic Flow Management in Brazil
A. Timoszczuk, W. Pizzo, G. Staniscia, E. Siewerdt

Collection of open chapters of books in transport research (2010). Vol. 2010, 58

Abstract
At recent years, air traffic demand increased at double-digit figures at several Brazilian airports and as a consequence increased controller workload was observed at many Sectors of the Air Traffic Control Facilities, with clear indications that demand consistently surpassed the available capacity of airports and air traffic control units. Although determination of air traffic control capacity values is still a very subjective and controversial issue, with no proven and universally accepted method in place, there is no doubt that there are limits and operating at values above a certain threshold will impact the systems efficiency, and, ultimately, also its safety. Demand is defined as the number of aircraft requesting to use the Air Traffic Management system ABSTRACT Document type: Part of book or chapter of book
Abstract
At recent years, air traffic demand increased at double-digit figures at several Brazilian airports and as a consequence increased controller workload was observed at many [...]
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Efficient Algorithm for Embedding Hypergraphs in a Cycle
Q. Gu, Y. Wang

Collection of open chapters of books in transport research (2010). Vol. 2010, 57

Abstract
The problem of Minimum Congestion Hypergraph Embedding in a Cycle (MCHEC) is to embed the hyperedges of a hypergraph as paths in a cycle such that the maximum congestion (the maximum number of paths that use any single link in the cycle) is minimized. This problem has many applications, including minimizing communication congestions in computer networks and parallel computations. The MCHEC problem is NP-hard. We give a 1.8-approximation algorithm for the problem. This improves the previous 2-approximation results. The algorithm has the optimal O(mn) time for the hypergraph with m hyperedges and n nodes. Document type: Part of book or chapter of book
Abstract
The problem of Minimum Congestion Hypergraph Embedding in a Cycle (MCHEC) is to embed the hyperedges of a hypergraph as paths in a cycle such that the maximum congestion (the [...]
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Assessing the environmental co benefits of climate change actions
K. Hamilton, S. Akbar

Collection of open chapters of books in transport research (2010). Vol. 2010, 56

Abstract
This internal background paper has been prepared to help inform the 2010 environment strategy with respect to a proposed way forward on use of country systems. The World Bank Group environment strategy is built on three pillars: leveraging natural resources for growth and poverty reduction; managing the environmental risks to growth and development; and transforming growth paths. As part of its exploration of these three pillars, the strategy considers the question of environmental co-benefits of climate change actions. In particular, it poses the question of potential trade-offs between actions to address climate change and other local and regional environmental priorities, and considers how to maximize co-benefits arising from climate action. The primary objective of this background paper is to assess the potential for climate change mitigation and adaptation actions to provide environmental co-benefits, particularly in the quality of environmental media, flow of ecosystem services, and maintenance of biodiversity. To accomplish this, the paper is organized in five sections: section one gives provision of an organizing framework to identify and classify potential co-benefits; section two gives summary of the external literature on co-benefits; section three gives review of examples from the World Bank portfolio; section four presents initial thoughts on creation of enabling conditions for co-benefit provision; and section five gives review of implications for the environment strategy. Document type: Book
Abstract
This internal background paper has been prepared to help inform the 2010 environment strategy with respect to a proposed way forward on use of country systems. The World Bank [...]
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QoS Dynamic Routing in Content Delivery Networks
K. Walkowiak

Collection of open chapters of books in transport research (2010). Vol. 2010, 55

Abstract
Recently, much research in quality of service (QoS) routing has focused on the unicast communication technique. However, Content Delivery Network (CDN) approach becomes popular because CDN enables effective and inexpensive improvement of Internet service quality. Therefore, we analyze in this paper a network processing two kinds of demands: content demands to CDN servers and standard unicast demands. Since MPLS defines effective mechanism for traffic engineering, we assume that the CDN is located in MPLS network. To examine the QoS performance of CDN-enabled MPLS network we propose new constraint-based algorithms for CDN server selection and evaluate relative performance of these algorithms and the most effective existing QoS unicast routing algorithms in terms of the demand rejection ratio. Document type: Part of book or chapter of book
Abstract
Recently, much research in quality of service (QoS) routing has focused on the unicast communication technique. However, Content Delivery Network (CDN) approach becomes popular [...]
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Interdomain traffic engineering with minimal BGP configurations
S. Uhlig, O. Bonaventure, B. Quoitin

Collection of open chapters of books in transport research (2010). Vol. 2010, 54

Abstract
We propose a method based on multi-objective combinatorial optimization to perform interdomain traffic engineering with minimal BGP configurations. Our method relies on an evolutionary algorithin that tries to minimize an objective function by finding the successive BGP filters to be applied on the BGP routes. We study the impact of the number of providers, the traffic aggregation in the AS-level topology and the objective function on the behavior of our algorithm. Document type: Part of book or chapter of book
Abstract
We propose a method based on multi-objective combinatorial optimization to perform interdomain traffic engineering with minimal BGP configurations. Our method relies on an [...]
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Multi agent environment for dynamic transport planning and scheduling
J. Kozlak, J. Créput, V. Hilaire, A. Koukam

Collection of open chapters of books in transport research (2010). Vol. 2010, 53

Abstract
Nowadays, transport requests of the society are becoming more and more common and important. Computer systems may be a useful tool for transport companies. This paper is aimed at presenting a system which simulates the functioning of a transport company. The theoretical problem, which needs to be solved, is a dynamic Pickup and Delivery Problem with Time Windows and capacity constraints (PDPTW). The nature of the problem, its distribution and the possibility of using a lot of autonomous planning modules, predestines to apply a multi-agent approach. Multi-agent approach facilitates the introduction of elements which do not appear in classical PDPTW as company organisation, different strategies of requests acceptation by different vehicles or communication among vehicles. Document type: Part of book or chapter of book
Abstract
Nowadays, transport requests of the society are becoming more and more common and important. Computer systems may be a useful tool for transport companies. This paper is aimed [...]
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Optimization of Traffic Behavior via Fluid Dynamic Approach
B. Piccoli, C. DApice, R. Manzo

Collection of open chapters of books in transport research (2010). Vol. 2010, 52

Abstract
Traffic regulation techniques for the optimization of car traffic flows in congested urban networks was considered. The approach used for the description of traffic flows is of fluiddynamic type. The main advantages of this approach, with respect to existing ones, can be summarized as follows. The fluid-dynamic models are completely evolutive, thus they are able to describe the traffic situation of a network at every instant of time. This overcomes the difficulties encountered by many static models. An accurate description of queues formation and evolution on the network is possible. The theory permits the development of efficient numerical schemes also for very large networks. This is possible since traffic at junctions is modelled in a simple and computationally convenient way (resorting to a linear programming problem). The performance analysis of the networks was made through the use of different cost functionals, measuring car average velocity weighted or not weighted with the number of cars moving on each road, the average travelling time, velocity variation, kinetic energy, etc. Exact analytical results were given for simple junctions of 1 ×2 and 2 × 1 type, and then used in order to simulate more complex urban networks. Moreover the problem of emergency vehicles transit has been treated. The problem has been faced choosing a route for emergency vehicles (not dedicated, i.e. not limited only to emergency needs) and redistributing traffic flows at junctions on the basis of the current traffic load in such way that emergency vehicles could travel at the maximum allowed speed along the assigned roads (and without blocking the traffic on other roads). All the optimization results have been obtained using a decentralized approach, i.e. an approach which sets local optimal parameters for each junction of the network. In future we aim to extend the optimization results to more general junctions and to explore global optimization techniques. In addition, the definition and optimization of functionals which take into account the emission and propagation of pollutants produced by cars might provide powerful technological tools to rationalize the design and use of public and private transportation resources, and to reduce unpleasant effects of urban traffic on the environment. Document type: Part of book or chapter of book
Abstract
Traffic regulation techniques for the optimization of car traffic flows in congested urban networks was considered. The approach used for the description of traffic flows [...]
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Passive long range detection of aircraft towards a field deployable sense and avoid system
D. Dey, C. Geyer, S. Singh, M. Digioia

Collection of open chapters of books in transport research (2010). Vol. 2010, 51

Abstract
Unmanned Aerial Vehicles (UAVs) typically fly blind with operators in distant locations. Most UAVs are too small to carry a traffic collision avoidance system (TCAS) payload or transponder. Collision avoidance is currently done by flight planning, use of ground or air based human observers and segregated air spaces. US lawmakers propose commercial unmanned aerial systems access to national airspace (NAS) by 30th September 2013. UAVs must not degrade the existing safety of the NAS, but the metrics that determine this have to be fully determined yet. It is still possible to state functional requirements and determine some performance minimums. For both manned and unmanned aircraft to fly safely in the same airspace UAVs will need to detect other aircraft and follow the same rules as human pilots. Document type: Part of book or chapter of book
Abstract
Unmanned Aerial Vehicles (UAVs) typically fly blind with operators in distant locations. Most UAVs are too small to carry a traffic collision avoidance system (TCAS) payload [...]
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Handling two way tcp traffic in asymmetric networks
F. Louati, C. Barakat, W. Dabbous

Collection of open chapters of books in transport research (2010). Vol. 2010, 50

Abstract
The TCP congestion control protocol is mainly designed for bandwidth symmetric paths. As two-way asymmetric connections will probably become common case in the future with the widespread use of ADSL, satellites and other high-speed technologies, it is important to make sure that congestion will be properly handled in these environments. To this end, we propose in this paper a new Adaptive Class-based Queuing mechanism called ACQ for handling two-way TCP traffic over links that exhibit bandwidth asymmetry. ACQ runs at the entry of the slow link and relies on two separate classes, one for ACK packets and one for Data packets. ACQ proposes to adapt the weights of both classes according to the crossing traffic in order to maximize some utility function defined by the user or the network operator. We show by simulations that our mechanism is able to reach a good utilization of the available resources, managing then to maximize the satisfaction of the user of such asymmetric connections. Document type: Part of book or chapter of book
Abstract
The TCP congestion control protocol is mainly designed for bandwidth symmetric paths. As two-way asymmetric connections will probably become common case in the future with [...]
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Reducing packet loss by taking long range dependences into account
J. Alvarez-Hamelin, P. Fraigniaud

Collection of open chapters of books in transport research (2010). Vol. 2010, 48

Abstract
We show that the fractal behavior of Internet traffic can be efficiently and practically employed to significantly reduce packet-loss. Thanks to recent advances in the theory of self-similar processes, we define the probabilistic congestion of a link, based on an estimated computation of the packet-loss probability over that link. This congestion parameter allows valid predictions on the future behavior of the network, on which one can base efficient routing strategies. We show how to implement the computation of the probabilistic congestion, and we illustrate several applications for improving unicast and multicast protocols. Document type: Part of book or chapter of book
Abstract
We show that the fractal behavior of Internet traffic can be efficiently and practically employed to significantly reduce packet-loss. Thanks to recent advances in the [...]
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Automatic Management of the QoS within an Architecture Integrating New Transport and IP Services in a DiffServ Internet
C. Chassot, G. Auriol, M. Diaz

Collection of open chapters of books in transport research (2010). Vol. 2010, 47

Abstract
Lots of research works have been performed for about ten years around the QoS problem in the Internet, both but separately at the Transport and at the IP levels. Taking into account the emerging traffic engineering-based QoS solutions (Diffserv-oriented), this paper targets the integration of new Transport services and protocols together with these solutions. Starting from performance measurements performed over a national DiffServ platform, contributions exposed here deal with the proposition and the implementation of a session level protocol allowing the application programmers to be masked with the complexity of choosing the underlying new Transport and IP services, still being provided with a per flow QoS. Document type: Part of book or chapter of book
Abstract
Lots of research works have been performed for about ten years around the QoS problem in the Internet, both but separately at the Transport and at the IP levels. Taking into [...]
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A framework of map comparison methods to evaluate geosimulation models from a geospatial perspective
A. Hagen-Zanker, P. Martens

Collection of open chapters of books in transport research (2011). Vol. 2011, 76

Abstract
Geosimulation is a form of microsimulation that seeks to understand geographical patterns and dynamics as the outcome of micro level geographical processes. Geosimulation has been applied to understand such diverse systems as lake ecology, traffic congestion and urban growth. A crucial task common to these applications is to express the agreement between model and reality and hence the confidence one can have in the model results. Such evaluation requires a geospatial perspective; it is not sufficient if the micro-level interactions are realistic. Importantly the interactions should be such that the meso and macro level patterns that emerge from the model are realistic. In recent years, a host of map comparison methods have been developed that address different aspects of the agreement between model and reality. This paper places such methods in a framework to systematically assess the breadth and width of model performance. The framework expresses agreement at the continuum of spatial scales ranging from local to the whole landscape and separately addresses agreement in structure and presence. A common reference level makes different performance metrics mutually comparable and guides the interpretation of results. The framework is applied for the evaluation of a constrained cellular automata model of the Netherlands. The case demonstrates that a performance assessment lacking either a multi-criteria and multi-scale perspective or a reference level would result in an unbalanced account and ultimately false conclusions. Document type: Part of book or chapter of book
Abstract
Geosimulation is a form of microsimulation that seeks to understand geographical patterns and dynamics as the outcome of micro level geographical processes. Geosimulation [...]
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High performance heuristics for optimization in stochastic traffic engineering problems
E. Nikolova

Collection of open chapters of books in transport research (2010). Vol. 2010, 46

Abstract
We consider a stochastic routing model in which the goal is to find the optimal route that incorporates a measure of risk The problem arises in traffic engineering, transportation and even more abstract settings such as task planning (where the time to execute tasks is uncertain), etc The stochasticity is specified in terms of arbitrary edge length distributions with given mean and variance values in a graph The objective function is a positive linear combination of the mean and standard deviation of the route Both the nonconvex objective and exponentially sized feasible set of available routes present a challenging optimization problem for which no efficient algorithms are known In this paper we evaluate the practical performance of algorithms and heuristic approaches which show very promising results in terms of both running time and solution accuracy. Document type: Part of book or chapter of book
Abstract
We consider a stochastic routing model in which the goal is to find the optimal route that incorporates a measure of risk The problem arises in traffic engineering, transportation [...]
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Modelling aspects of longitudinal control in an integrated driver model
B. Wortelen, M. Zilinski, M. Baumann, E. Muhrer, M. Vollrath, M. Eilers, A. Lüdtke, C. Möbus

Collection of open chapters of books in transport research (2011). Vol. 2011, 72

Abstract
Simulating and predicting behaviour of human drivers with Digital Human Driver Models (DHDMs) has the potential to support designers of new (partially autonomous) driver assistance systems (PADAS) in early stages with regard to understanding how assistance systems affect human driving behaviour. This paper presents the current research on an integrated driver model under development at OFFIS within the EU project ISi-PADAS. We will briefly show how we integrate improvements into CASCaS, a cognitive architecture used as framework for the different partial models which form the integrated driver model. Current research on the driver model concentrates on two aspects of longitudinal control (behaviour a signalized intersections and allocation of visual attention during car following). Each aspect is covered by a dedicated experimental scenario. We show how experimental results guide the modelling process. Document type: Part of book or chapter of book
Abstract
Simulating and predicting behaviour of human drivers with Digital Human Driver Models (DHDMs) has the potential to support designers of new (partially autonomous) driver assistance [...]
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Comfortable Driver Behavior Modeling for Car Following of Pervasive Computing Environment
Y. Liu, Z. Wu

Collection of open chapters of books in transport research (2010). Vol. 2010, 45

Abstract
This paper demonstrates a novel car-following model based on driver or passengers comfort. As we know, hasty deceleration during emergency brake will cause passengers feel uncomfortable. According to the relationship between brake acceleration and peoples comfortable feeling, the comfortable model is setup. The model calculates the following cars acceleration by measuring the distance between the following car and the preceding car, the velocity of the following car, and controls the cars acceleration to make driver and passengers feel comfort. The paper combine the model with the pervasive computing concept, provoke the pervasive computing driver behavior modeling idea and turn it into reality to increase the adaptability and reliability of cars parts, when car equipped with this device, the prospect is not only the assistant driver or comfortable driver are realized in the car-following circumstance, but also the whole cars performance will be improved. Document type: Part of book or chapter of book
Abstract
This paper demonstrates a novel car-following model based on driver or passengers comfort. As we know, hasty deceleration during emergency brake will cause passengers feel [...]
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Computational concerns in the integration of unmanned airborne systems into controlled airspace
C. Johnson

Collection of open chapters of books in transport research (2010). Vol. 2010, 44

Abstract
Unmanned Airborne Systems (UAS) offer significant benefits for long duration missions. They can also be used in situations where it is inappropriate to expose aircrew to increased levels of risk. Partly in consequence, they continue to experience accident rates that are significantly higher than those for most conventional aircraft. It can also be argued that increased mishap rates are due to lower standards of design and maintenance. UAS are, therefore, largely confined to segregated areas that are well away from other airspace users. There are growing commercial and political pressures for them to be integrated into airspace that is directly under the control of air traffic management. Police agencies would like to deploy miniature UAS in populated areas, for example, to augment conventional helicopter operations. There are proposals to operate unmanned freight operations from existing airports. Longer-term proposals include the use of UAS technology to replace the co-pilot. Automated systems might intervene only if the single human pilot is incapacitated. The following pages focus on the computational issues that form one part of wider set of 'system safety' concerns that must be addressed before UAS operations can be integrated into controlled airspace. Document type: Part of book or chapter of book
Abstract
Unmanned Airborne Systems (UAS) offer significant benefits for long duration missions. They can also be used in situations where it is inappropriate to expose aircrew to increased [...]
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Public Transport Capacity Analysis Procedures for Developing Cities
J. Reilly, H. Levinson

Collection of open chapters of books in transport research (2011). Vol. 2011, 63

Abstract
The introduction of urban rail transit and high performance/quality/capacity bus transit systems throughout the world has dramatically improved the mobility of residents of cities in which they operate. The objectives of this work are: to provide a technical resource for transit planners and designers in developing cities in their public transport capacity and performance analysis work irrespective of mode. This report recommends methods of achieving practical transit capacity during normally encountered operating conditions. Where capacity is influenced by a measure of dispersion of some characteristic such as stop dwell time or vehicle headway, this is also noted. The purpose of measuring capacity is not just to provide a measure of system capability to transport passengers but also to provide some insight into the effect of service and physical design on customer service quality. When the demand for a service exceeds its schedule design capacity, service quality deteriorates either due to overcrowding on vehicles or at station platforms or diminished ability of customers to board the next arriving transport vehicle since it is already fully loaded, increased dwell times and hence decrease revenue speeds. The importance of service quality in transit capacity analysis cannot be overstated. Transit operators should be mindful that the urban transportation marketplace is more competitive. While it might be technically possible to design a service using a loading standard of 7 or 8 passengers per square meter, a number of customers will find that level intolerable and will seek alternate means of travel including walking (in the case of short distance trips), riding with someone else, riding taxis or purchasing a motorcycle or car. Accordingly, such loading standards should be thought of as interim measures until higher capacity at lower crowding can be achieved. Document type: Book
Abstract
The introduction of urban rail transit and high performance/quality/capacity bus transit systems throughout the world has dramatically improved the mobility of residents of [...]
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Schneller öfter weiter immer dümmer
H. Knoflacher

Collection of open chapters of books in transport research (2011). Vol. 2011, 62

Abstract
Jede Beschleunigung erhöht das Risiko und die Häufigkeit von Fehlern, wenn Rückkopplung und Kontrolle nicht folgen können. Die technische Beschleunigung sowohl in der physischen Mobilität wie auch im Informationssystem führt nicht, wie zu erwarten wäre, zu intelligenteren, sondern zu dümmeren Ergebnissen. Was im Individualbereich zunächst als großer Vorteil erscheint - die mit externer Energie angetriebenen Verkehrsmittel, insbesondere das Auto - führt im System zu immer größerer Abhängigkeit von außen und zu Siedlungsstrukturen, die nicht nachhaltig sind. Die Dummheit der Verkehrs- und Stadtplanung muss von den Bewohnern mit immer größerem Einsatz immer teurer werdender Energie bezahlt werden. Die Ursache liegt in der heutigen Parkraumorganisation, die die Gesellschaft zwingt, an jedem Ort ihrer Aktivitäten in unmittelbarer Nähe Parkplätze anzuordnen, eine Folge der Reichsgaragenordnung aus 1939. Diese zwanghaft physische Kopplung kann nur aufgelöst werden, wenn man sie physisch löst, indem die Wege zum geparkten Auto nicht kürzer sein dürfen als die zur Haltestelle des öffentlichen Verkehrs und auch im Autoverkehr die Marktwirtschaft eingeführt wird. Dies führt zu intelligenteren Lösungen nicht nur in den Siedlungsstrukturen, sondern auch im individuellen Verhalten. Acceleration enhances the risk of mistakes if it is not controlled by feedback loops. The effect of modern technical fast transport systems like cars of information systems are not more intelligent solutions but the contrary. Benefits for the individual car users create more stupid settlement structures with increasing demand on external fossil fuel to be kept alive. Monofunctional urban structures have replaced the former vital pedestrian based sustainable cities. The main cause is the prevailing parking organization, which is based on a regulation from 1939 the Reichsgaragenordnung, forcing everybody to provide enough parking facilities adjacent to each human activity. This establishes an enormous binding force between man and car. This trap can only be opened if the walking distance to and from the parked car is longer than to the public transport stop and if market economy is introduced into the car traffic system. Anyone parking at home has to pay the full cost he creates for the society and the environment. Document type: Book
Abstract
Jede Beschleunigung erhöht das Risiko und die Häufigkeit von Fehlern, wenn Rückkopplung und Kontrolle nicht folgen können. Die technische Beschleunigung sowohl in der [...]
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The Democratic Republic of Congo's infrastructure: A continental perspective
V. Foster, D. Benitez

Collection of open chapters of books in transport research (2010). Vol. 2010, 43

Abstract
The Africa Infrastructure Country Diagnostic (AICD) has gathered and analyzed extensive data on infrastructure in around 40 Sub-Saharan countries, including the Democratic Republic of Congo (DRC). The results have been presented in reports covering different areas of infrastructure ICT, irrigation, power, transport, water and sanitation and different policy areas, including investment needs, fiscal costs, and sector performance. This report presents the key AICD findings for the DRC, allowing the country's infrastructure situation to be benchmarked against that of its African peers. Given that the DRC is a fragile state trying to catch up with other low-income countries (LICs) in the region, both fragile-state and LIC African benchmarks will be used to evaluate the DRC's situation. Detailed comparisons will also be made with immediate regional neighbors in Central Africa. Several methodological issues should be borne in mind. First, because of the cross-country nature of data collection, a time lag is inevitable. The period covered by the AICD runs from 2001 to 2006. Most technical data presented are for 2006 (or the most recent year available), while financial data are typically averaged over the available period to smooth out the effect of short-term fluctuations. Second, in order to make comparisons across countries, indicators had to be standardized to place the analysis on a consistent basis. This means that some of the indicators presented here may be slightly different from those that are routinely reported and discussed at the country level. During the period from 2001 to 2005, per capita economic growth in DRC was on average 2.1 percent higher than during the period from 1991 to 1995. Despite this improvement, growth levels, which oscillated between 4 and 8 percent in the early 2000s, still fell short of the sustained 7 percent per year needed to meet the Millennium Development Goals (MDGs). Improved telecommunications infrastructure has been the main driver of this change, contributing 1.1 percentage points to the country's per capita growth rate. Deficiencies in power infrastructure, on the other hand, held back per capita growth by 0.25 percentage point over this period. Document type: Book
Abstract
The Africa Infrastructure Country Diagnostic (AICD) has gathered and analyzed extensive data on infrastructure in around 40 Sub-Saharan countries, including the Democratic [...]
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Energieeffiziente Mobilität durch Aktivierung menschlicher Ressourcen am Beispiel der Stadt Schwäbisch Gmünd
S. Michels

Collection of open chapters of books in transport research (2011). Vol. 2011, 58

Abstract
Dieser Artikel zeigt am Beispiel der Stadt Schwäbisch Gmünd, wie sich auch in mittelgroßen Städten und Gemeinden im ländlichen Raum Maßnahmen verwirklichen lassen, um eine energieeffiziente Mobilität zu forcieren. Ein besonderer Schwerpunkt liegt hierbei auf dem Menschen, nicht auf technologischem Fortschritt. Der Artikel stellt zunächst die Ausgangssituation in Schwäbisch Gmünd dar. Im Weiteren beleuchtet er die wesentlichen mobilitätsbezogenen Maßnahmen des Energieeffizienzkonzeptes und zeigt Möglichkeiten auf, wie Energie im Bereich der Mobilität unter Berücksichtigung lokaler Besonderheiten bilanziert werden kann. This paper uses the example of Schwäbisch Gmünd to suggest ideas how medium-sized towns and communes especially in the rural area can implement arrangements to force energy-efficient mobility. The solutions focus mainly on human beings and their mobility behavior, not only on technological advance. First the paper presents the initial situation in Schwäbisch Gmünd. Further it shows the essential mobility-related arrangements of the energy efficiency strategy. Finally it identifies options to account energy in regard to mobility considering the local specific characteristics. Document type: Book
Abstract
Dieser Artikel zeigt am Beispiel der Stadt Schwäbisch Gmünd, wie sich auch in mittelgroßen Städten und Gemeinden im ländlichen Raum Maßnahmen verwirklichen lassen, um [...]
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Using Fourier Descriptors and Spatial Models for Traffic Sign Recognition
F. Larsson, M. Felsberg

Collection of open chapters of books in transport research (2011). Vol. 2011, 57

Abstract
Traffic sign recognition is important for the development of driver assistance systems and fully autonomous vehicles. Even though GPS navigator systems works well for most of the time, there will always be situations when they fail. In these cases, robust vision based systems are required. Traffic signs are designed to have distinct colored fields separated by sharp boundaries. We propose to use locally segmented contours combined with an implicit star-shaped object model as prototypes for the different sign classes. The contours are described by Fourier descriptors. Matching of a query image to the sign prototype database is done by exhaustive search. This is done efficiently by using the correlation based matching scheme for Fourier descriptors and a fast cascaded matching scheme for enforcing the spatial requirements. We demonstrated on a publicly available database state of the art performance. "p"Original Publication: Fredrik Larsson and Michael Felsberg, Using Fourier Descriptors and Spatial Models for Traffic Sign Recognition, SCIA konferens, 23-27 May 2011, Ystad Sweden, 2011, Lecture Notes in Computer Science, Image Analysis, 238-249. http://dx.doi.org/10.1007/978-3-642-21227-7_23 Copyright: Springer Document type: Part of book or chapter of book
Abstract
Traffic sign recognition is important for the development of driver assistance systems and fully autonomous vehicles. Even though GPS navigator systems works well for most [...]
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Wirtschaft und Mobilität - im Wechselspiel mit Gesellschaft und Raum: Einführung
R. Meng, K. Ruppenthal

Collection of open chapters of books in transport research (2011). Vol. 2011, 53

Abstract
Document type: Book
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A proposal for inter domain qos routing based on distributed overlay entities and qbgp
M. Yannuzzi, A. Fonte, X. Masip-Bruin, E. Monteiro, S. Sánchez-López, M. Curado, J. Domingo-Pascual

Collection of open chapters of books in transport research (2010). Vol. 2010, 38

Abstract
This paper proposes a novel and incremental approach to Inter-Domain QoS Routing. Our approach is to provide a completely distributed Overlay Architecture and a routing layer for dynamic QoS provisioning, and to use QoS extensions and Traffic Engineering capabilities of the underlying BGP layer for static QoS provisioning. Our focus is mainly on influencing how traffic is exchanged among non-directly connected multi-homed Autonomous Systems based on specific QoS parameters. We provide evidence supporting the feasibility of our approach by means of simulation. Document type: Part of book or chapter of book
Abstract
This paper proposes a novel and incremental approach to Inter-Domain QoS Routing. Our approach is to provide a completely distributed Overlay Architecture and a routing layer [...]
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Real time visualization of wake vortex simulations using computational steering and beowulf clusters
A. Modi, L. Long, P. Plassmann

Collection of open chapters of books in transport research (2010). Vol. 2010, 37

Abstract
In this paper, we present the design and implementation of POSSE, a new, lightweight computational steering system based on a client/server programming model. We demonstrate the effectiveness of this software system by illustrating its use for a visualization client designed for a particularly demanding real-time application--wake-vortex simulations for multiple aircraft running on a parallel Beowulf cluster. We describe how POSSE is implemented as an object-oriented, class-based software library and illustrate its ease of use from the perspective of both the server and client codes. We discuss how POSSE handles the issue of data coherency of distributed data structures, data transfer between different hardware representations, and a number of other implementation issues. Finally, we consider how this approach could be used to augment AVOSS (an air traffic control system currently being developed by the FAA) to significantly increase airport utilization while reducing the risks of accidents. Document type: Part of book or chapter of book
Abstract
In this paper, we present the design and implementation of POSSE, a new, lightweight computational steering system based on a client/server programming model. We demonstrate [...]
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A Contribution to Urban Transport System Analyses and Planning in Developing Countries
G. Avila

Collection of open chapters of books in transport research (2010). Vol. 2010, 36

Abstract
The purpose of this chapter is to provide a contemporary statement of existing approaches to transport-land use planning in urban and regional areas to advise practising transport planners and students. The chapter concentrates on the knowledge that are available for the synthesis, analysis, and evaluation of alternative land use-transport-systems plans and regulations. First, the transportation planner must develop an understanding of the planning process before attempting to address herself to the broader polices issues. The first objective of this chapter is to provide transportation planners with an understanding of the land-use models and their application to urban and regional planning problems. The final objective covers policy, regulations and plans. Absence of physical space between people and firms is the definition of Economists to cities. Cities appear to supply the necessity to eliminate transport costs. Density lowers the costs of interacting with other people and speeds the flow of goods, people and ideas. The location and structure of cities is driven by the desire to eliminate transport costs. In this context, transportation technologies have been the primary determinant of the location and structure of cities. There is increasing concern across the world about increasing traffic congestion and the costs it imposes, particularly on accessibility, the environment, other social factors, such as accidents, and the economy in general. Growing personal car-mileage is engendering the well-known effects on the environment and transport systems, especially roads, which are not able to cope with the increasing amounts of traffic. Further development of innovative, integrated and well-balanced policies is strongly needed. Strong and ongoing growth in mobility, especially in road traffic, means that transport trends are unsustainable if only current policies are pursued: with constraints on resources, space, safety and the environment there are only limited possibilities to extend transport supply to safeguard accessibility. It is quite clear that the need for travel cannot really be avoided; it is crucial for the performance of social and economic functions in any society. People are not travelling much more often than twenty years ago, but they are travelling further and with greater use of the private car. Increasing car ownership is a central component of this (Transland, 2000). There is a lack of knowledge about the interaction between land use and transport and the related planning consequences. Institutional demands for integrated policymaking is 13 Document type: Part of book or chapter of book
Abstract
The purpose of this chapter is to provide a contemporary statement of existing approaches to transport-land use planning in urban and regional areas to advise practising transport [...]
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Public private networks
O. Bohl, R. Schaefer, U. Winand

Collection of open chapters of books in transport research (2010). Vol. 2010, 35

Abstract
The provision of services and the production of wares and services nowadays often require the cooperation of partners from different sectors. These cooperations can comprise public and private organizations, companies, universities, NGOs, and other groupings as well as individuals. The cooperative collaboration is esteemed as a core element of democratic social systems within a free market economy (Kirsch, 1996; Pongsiri, 2001). As one relevant method of organizing such collaborations, public private networks (PPN) extend the concept of public private partnerships (PPP) by adding the idea of networking and its core elements. From a scientific point of view as well as from the business perspective there is a shortcoming in the systematic processing of ideas, motivations, and forms as well as implications for internal and external participants of PPPs/PPNs. In the following, partnerships between partners from public and private business environments will be discussed. (Pongsiri, 2001) In particular, PPPs and PPNs in the field of academic education will be portrayed, since the cooperation in knowledge intensive areas is seen as an important issue. (Inkpen, 1996; Seufert, von Krogh, & Back, 1999) In the following the concepts of PPPs and PPNs will be explained. This will be done by an extensive literature review. The aim is to provide the required definitions and to discuss the incorporated views of others. Document type: Part of book or chapter of book
Abstract
The provision of services and the production of wares and services nowadays often require the cooperation of partners from different sectors. These cooperations can comprise [...]
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Optimization of bandwidth allocation in communication networks with penalty cost
J. Wu, Y. Yue, S. Wang

Collection of open chapters of books in transport research (2010). Vol. 2010, 34

Abstract
In this paper, we present an analysis on optimization and risk management in Communication Networks (CNs). The model is proposed for offline traffic engineering optimization, which takes a centralized view of bandwidth allocation, performance control, and risk control of network profit shortfall. First, we introduce a linear penalty cost in the CN optimization model and derive the optimal bandwidth capacity with the penalty cost. Then, we use the mean-variance approach to analyze the profit shortfall risk in CNs. Finally, numerical results are shown to reveal the impact of the penalty cost on the CNs performance. Document type: Part of book or chapter of book
Abstract
In this paper, we present an analysis on optimization and risk management in Communication Networks (CNs). The model is proposed for offline traffic engineering optimization, [...]
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Improving Perceived Web Performance by Size Based Congestion Control
T. Ziegler, H. Tran, E. Hasenleithner

Collection of open chapters of books in transport research (2010). Vol. 2010, 33

Abstract
Flow size based congestion control has the potential to improve user perceived Web performance due to the heavy tailed characteristic of file size distributions in the Web. After discussing the benefits and drawbacks of transport protocol and router based solutions for size based congestion control, guidelines for algorithm design are developed. Using these guidelines we find that size based congestion control needs to incorporate TCP models to avoid undesirable user incentives. Based on this insight we specify enhancements to TCP featuring size based congestion control and provide arguments for parameter settings. It is shown by simulation that our modified version of TCP significantly outperforms NewReno from a user perspective in scenarios using realistic models for Web traffic and topologies with multiple congested links. Document type: Part of book or chapter of book
Abstract
Flow size based congestion control has the potential to improve user perceived Web performance due to the heavy tailed characteristic of file size distributions in the Web. [...]
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A scenarios based methodology for it portfolio planning
S. Loh, R. Saldaña, L. Becker

Collection of open chapters of books in transport research (2010). Vol. 2010, 32

Abstract
One of the main topics in IT Portfolio Management, according to IT Governance models, is to plan and control information systems that are aligned with the company mission and objectives. The goal of the IT Portfolio Planning is to define which information systems are necessary and with which priority. In general, planning methodologies trace directions from a present point to a future and desired target. However, in many cases, companies can not control situations; events may occur that can not be avoided. A scenarios-based planning methodology can help managers to identify future events, their probability and consequences. A scenario represents a future situation that can not be controlled nor can be avoided. However, the study of future scenarios can help managers to plan reactions, so that company can create mechanisms for avoiding problems or for minimizing bad consequences. The goal of this chapter is to present an adaptation of the scenario-based methodology for IT and Information Systems Planning. The chapter will describe in details each step of the proposed methodology and discuss a study case. Steps include the identification of different scenarios and their corresponding antecedent events, the determination of probabilities and consequences of the events, how to calculate risks and how to plan Information Systems and IT resources to manage each scenario. Document type: Part of book or chapter of book
Abstract
One of the main topics in IT Portfolio Management, according to IT Governance models, is to plan and control information systems that are aligned with the company mission [...]
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Auf dem Weg zu einem Grundangebot von Mobilität in ländlichen Räumen: Probleme, Ursachen und Handlungsoptionen
P. Küpper

Collection of open chapters of books in transport research (2011). Vol. 2011, 39

Abstract
Der Beitrag geht der Frage nach, wie in ländlichen Räumen ein Grundangebot von Mobilität gewährleistet bzw. hergestellt werden kann. Dazu werden zunächst die Besonderheiten der Mobilität in ländlichen Räumen im Vergleich zu urbanen Gebieten herausgearbeitet sowie aktuelle Trends, Probleme und Konsequenzen für das ÖPNV-Angebot beleuchtet. Schließlich werden verschiedene Handlungsoptionen vorgestellt, wie mit diesen Entwicklungen umgegangen werden kann, um ein Grundangebot sicherstellen zu können. Dabei werden häufig bedarfsgesteuerte Bedienformen als Lösung angepriesen. Die Analyse zeigt jedoch, dass insbesondere in dünn besiedelten ländlichen Räumen erhebliche Finanzierungsdefizite zu erwarten sind. Deshalb werden weitere Alternativen, wie die Effizienzsteigerung im traditionellen ÖPNV, Bürgerbusse, organisierte Mitnahme im privaten Pkw, mobile und dezentrale Versorgung mit Dienstleistungen, Mitnahme durch andere Fahrdienste, Carsharing und Subjektförderung im ÖPNV diskutiert. Im Ergebnis zeigt sich, dass alle Handlungsoptionen sowohl Vor- als auch Nachteile aufweisen. Diese Vielfalt an Bedienformen kann jedoch dazu genutzt werden, das Angebot auf die spezifischen Bedingungen vor Ort zuzuschneiden, was zu einem abgestuften System von den Zentren zur Peripherie führt. The paper addresses the question how a basic provision of mobility could be assured in rural areas. To answer the research question, it analyses the particularities of rural mobility in comparison to urban areas, current trends and resulting problems for the public transport. Afterwards, the review presents different options for action to guarantee a basic mobility against these issues. In transport policy debates, demand responsive transport is often seen as a solution. However, many studies demonstrate the low potential of this transport service, mainly due to the low revenue-to-cost ratio of such services. Therefore, the paper discusses further alternatives including raising efficiency in traditional public transport, voluntary public transport, ride sharing in private cars or in cars of other transport services, mobile and decentral supply of services, car sharing and disbursing mobility vouchers. As a result, all researched alternatives have their particular strengths and weaknesses. The variety of mobility options can, thus, contribute to a tailor- made transport policy considering the specific local conditions. The conclusion comprises a gradual mobility system from core to periphery. Document type: Book
Abstract
Der Beitrag geht der Frage nach, wie in ländlichen Räumen ein Grundangebot von Mobilität gewährleistet bzw. hergestellt werden kann. Dazu werden zunächst die Besonderheiten [...]
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Charting a New Course
L. Andres, D. Sislen, P. Marin

Collection of open chapters of books in transport research (2010). Vol. 2010, 31

Abstract
Infrastructure plays a key role in promoting economic growth and opportunities.In particular, the efficient provision of basic infrastructure services, like water and sanitation, is a key ingredient in fostering a country's social and economic development. Previous studies have found that infrastructure has a positive impact on output, and can improve economic opportunity, including health and education for the poor, particularly in developing countries. In Argentina, a 2005 study, found that child mortality fell by 8 percent in areas that had experienced improved coverage and quality of basic water and sanitation through utility reform, with most of the reduction occurring in low-income areas where the water network expanded the most. More generally, Fay and Morrison found that allowing the poorest quintile in developing countries the same access to basic services as the richest quintile would reduce child mortality by 8 percent and child under development by 14 percent. Calderon and Serven also found a significant positive impact of infrastructure access and quality on overall inequality. Furthermore, the book sheds some light on how to address the main challenge for the future which may be to attract specialized operators to the smaller municipalities which do not currently have them. For that purpose in Colombia, for example, over the last two years, the policy framework has been focused on promoting the sector's development, by using the departments as the intermediate institutional level between the National Government and the municipalities, to formulate programs with regional impact and promote comprehensive investment plans. Document type: Book
Abstract
Infrastructure plays a key role in promoting economic growth and opportunities.In particular, the efficient provision of basic infrastructure services, like water and sanitation, [...]
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Regionale Mobilität - erneuerbar und klimafreundlich
H. Neumann

Collection of open chapters of books in transport research (2011). Vol. 2011, 33

Abstract
Weltweit streben immer mehr Regionen Energieautonomie an. Angesichts der Zukunftsrisiken Klimawandel und Erdölverknappung beabsichtigen sie, ihren Energiebedarf zu 100% aus eigenen erneuerbaren und daher CO2-neutralen Quellen zu decken. Während viele Regionen bei der Produktion von Elektrizität und Wärme große Erfolge erzielen, gibt es hinsichtlich der Deckung des Verkehrsenergiebedarfs noch großen Forschungsbedarf. Um regionale Energieautonomie zu erreichen, müssen sowohl die eigenen erneuerbaren Quellen optimal genutzt als auch der Energiebedarf durch Effizienzsteigerungen so weit wie möglich gesenkt werden. Im Artikel werden verschiedene technische und planerische Optionen für den Verkehrsbereich vorgestellt und diskutiert. Besonderes Augenmerk gilt dabei der Frage, inwieweit sich Verkehrsflächen für die Erzeugung erneuerbarer Energie eignen. Die Umstellung der Verkehrsenergieversorgung auf erneuerbare regionale Quellen ist Chance und Herausforderung zugleich. Viele der negativen Umweltfolgen fossiler Mobilität werden sich voraussichtlich deutlich verringern oder sogar verschwinden. Die Installation von Photovoltaik-Elementen und anderen Anlagen der Energieerzeugung im öffentlichen Raum könnte allerdings auch existierende räumliche Qualitäten gefährden. Benötigt werden daher innovative Planungskonzepte und -instrumente. Bedarf besteht auch für neue Organisationsformen von Mobilität. Städtebau, Stadt- und Regionalplanung werden daher beim Übergang zu regionaler Energieautonomie eine wichtige Rolle spielen. A growing number of regions throughout the world aim at energy autonomy. In order to avoid climate and energy risks, they try to cover their energy demand to 100% by regional, renewable and hence carbon-neutral sources. Many of these regions are very successful in providing electricity and caloric energy, but as far as the energy demand of transport is concerned, there is still a big need for basic research. In order to achieve regional energy autonomy, it is necessary to increase the production of renewable energy as well as to reduce the energy demand. The article presents and discusses a set of relevant technological and planning options for the field of transport. Particular attention is paid to the generation potential of transport infrastructures for renewable energy. The switch from fossil to renewable energy is a chance as well as a challenge. Many of the environmental impacts of fossil-fueled transport are likely to diminish or even disappear. But the insertion of pv panels and other energy generating equipment in open spaces could also endanger existing spatial qualities. Hence innovative design concepts and controls should be developed. There is also a need for new organizational models for mobility. Urban and regional planning and urban design will therefore play an important role in the transition to regional energy autonomy. Document type: Book
Abstract
Weltweit streben immer mehr Regionen Energieautonomie an. Angesichts der Zukunftsrisiken Klimawandel und Erdölverknappung beabsichtigen sie, ihren Energiebedarf zu 100% aus [...]
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Collaborative decision making and information sharing for air traffic management operations
O. Martins, D. Loubach, G. Meinerz, A. Cunha

Collection of open chapters of books in transport research (2010). Vol. 2010, 29

Abstract
One of the most notable concepts related to the future cooperative Air Traffic Management (ATM) is the Collaborative Decision Making (CDM). This new management philosophy of using collaborative technologies and procedures to enable ATM partners drives efforts towards the common goals of sharing and exchanging information. To support the implementation of CDM, a likely solution was found in the context of System of Systems (SoS), system integration, and interoperability. Service-Oriented Architecture (SOA) principles and technologies were recognized as one of the best alternatives to allow this implementation. Within this architecture, the System Wide Information Management (SWIM) has been developed on the last decade, and SWIM applications will be accessible to all ATM partners on the next decade by providing full airspace information, updated in real-time by all involved partners. This chapter presents an overview of key elements in information sharing for ATM and explains how SOA, SWIM, Aeronautical Information Management (AIM) and CDM support each other development. Document type: Part of book or chapter of book
Abstract
One of the most notable concepts related to the future cooperative Air Traffic Management (ATM) is the Collaborative Decision Making (CDM). This new management philosophy [...]
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Minimum interference routing the precomputation perspective
G. Rétvari

Collection of open chapters of books in transport research (2010). Vol. 2010, 26

Abstract
This paper focuses on the selection of bandwidth-guaranteed channels for communication sessions that require it. The basic idea comes from Minimum Interference Routing: select a feasible path that puts the least possible restriction on the transmission capacity offered by the network for other communicating parties. This is achieved by circumventing some critical bottleneck links. The main contribution of the paper is a method to assess the degree of link criticality facilitating efficient route precomputation even in the case, when up to date resource availability information is not immediately available. Document type: Part of book or chapter of book
Abstract
This paper focuses on the selection of bandwidth-guaranteed channels for communication sessions that require it. The basic idea comes from Minimum Interference Routing: select [...]
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Schneller, öfter, weiter: Herausforderungen für eine mobile Gesellschaft von morgen
J. Deffner

Collection of open chapters of books in transport research (2011). Vol. 2011, 31

Abstract
In dem Beitrag geht es um aktuelle Trends und Herausforderungen der deutschen und europäischen Mobilitätsentwicklung. Hierzu zählen neben der Klima- und Energierelevanz des Verkehrs Themen wie soziale Differenzierung, demographischer Wandel und kulturelle Aspekte in ihrer Bedeutung für Mobilität und Verkehr aus einer sozialökologischen Perspektive. Es gibt Vorzeichen für einen möglichen Paradigmenwandel, der v.a. auf eine Dekarbonisierung des Verkehrs abhebt. Ein neues Leitbild einer multioptionalen, intermodalen Personenmobilität wird skizziert, das die Bedürfnisse einer sich weiter differenzierenden und pluralisierenden Gesellschaft aufgreift. Es basiert auf dem Rahmenkonzept "nachhaltige Mobilitätskultur" und auf drei Ebenen von Angeboten, die ein multioptionales Verkehrsangebot bilden. This article examines current trends and challenges of German and European mobility development. This includes besides climate and energy relevance of transport topics such as social differentiation, demographic change and cultural aspects, and looks at their significance for mobility and traffic from a socio-ecological perspective. There are signs for a possible change of paradigms which mainly emphasize the decarbonsation of transport. A new vision of a multioptional, intermodal mobility is sketched. It embraces the needs of a society that is taking on an ever more differentiated and pluralistic form. It bases on the framing concept of "sustainable mobility culture" and three levels within a transport system which form multi-optional transport products. Document type: Book
Abstract
In dem Beitrag geht es um aktuelle Trends und Herausforderungen der deutschen und europäischen Mobilitätsentwicklung. Hierzu zählen neben der Klima- und Energierelevanz [...]
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Pipeline morphing and virtual pipelines
W. Luk, N. Shirazi, S. Guo, P. Cheung

Collection of open chapters of books in transport research (2010). Vol. 2010, 25

Abstract
Pipeline morphing is a simple but effective technique for reconfiguring pipelined FPGA designs at run time. By overlapping computation and reconfiguration, the latency associated with emptying and refilling a pipeline can be avoided. We show how morphing can be applied to linear and mesh pipelines at both word-level and bit-level, and explain how this method can be implemented using Xilinx 6200 FPGAs. We also present an approach using morphing to map a large virtual pipeline onto a small physical pipeline, and the trade-offs involved are discussed. Document type: Part of book or chapter of book
Abstract
Pipeline morphing is a simple but effective technique for reconfiguring pipelined FPGA designs at run time. By overlapping computation and reconfiguration, the latency associated [...]
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Furthering World Bank Group's Corporate Environmental Sustainability
M. Kumar, A. Rubinfield, J. Moore, S. Raposa, M. Fyodorova

Collection of open chapters of books in transport research (2010). Vol. 2010, 24

Abstract
The World Bank Group (WBG) has focused on reducing the environmental impacts of its internal operations and improving corporate environmental practices since 2002, when the WBG President announced WBG's commitment to Corporate Social Responsibility (CSR). The objective of this document is to summarize the actions WBG has taken thus far to reduce environmental impacts from internal operations and present an action plan to further integrate sustainability into WBG's internal operations. Although this work focuses on the environmental impact associated with WBG daily operations, the links between WBG policies and actions related to environmental management and the financial/social considerations are significant. The International Finance Corporation (IFC) footprint and World Bank corporate responsibility teams facilitate the sustainability commitment of the WBG and monitor and track its progress. These teams provide technical information and research support to a dedicated group of champions throughout the WBG who implement emission reduction activities. Budget for these activities flows primarily through the environment department, the general services department, and IFC facilities management and administration. The environment department and IFC facilities management each resource one staff member to provide back-up research support and to monitor and report on environmental metrics, with building engineers and managers and project officers from across the WBG contributing. Document type: Book
Abstract
The World Bank Group (WBG) has focused on reducing the environmental impacts of its internal operations and improving corporate environmental practices since 2002, when the [...]
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Making igp routing robust to link failures
A. Sridharan, R. Guérin

Collection of open chapters of books in transport research (2010). Vol. 2010, 23

Abstract
An important requirement of a robust traffic engineering solution is insensitivity to changes, be they in the form of traffic fluctuations or changes in the network topology because of link failures. In this paper we focus on developing a fast and effective technique to compute traffic engineering solutions for Interior Gateway Protocol (IGPs) environments that are robust to link failures in the logical topology. The routing and packet forwarding decisions for IGPs is primarily governed by link weights. Our focus is on computing a single set of link weights for a traffic engineering instance that performs well over all single logical link failures. Such types of failures, although usually not long lasting, of the order of tens of minutes, can occur with high enough frequency, of the order of several a day, to significantly affect network performance. The relatively short duration of such failures coupled with issues of computational complexity and convergence time due to the size of current day networks discourage adaptive reactions to such events. Consequently, it is desirable to a priori compute a routing solution that performs well in all such scenarios. Through computational evaluations we demonstrate that our technique yields link weights that perform well over all single link failures and also scales well, in terms of computational complexity, with the size of the network. Document type: Part of book or chapter of book
Abstract
An important requirement of a robust traffic engineering solution is insensitivity to changes, be they in the form of traffic fluctuations or changes in the network topology [...]
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Contesting sustainability in infrastructure planning the debate of the public interest in brisbane s boggo road busway development
K. Shibata, P. Sanders

Collection of open chapters of books in transport research (2010). Vol. 2010, 22

Abstract
Sustainable infrastructure demands that declared principles of sustainability are enacted in the processes of its implementation. However, a problem arises if the concept of sustainability is not thoroughly scrutinized in the planning process. The public interest could be undermined when the rhetoric of sustainability is used to substantiate a proposed plan. This chapter analyses the manifestation of sustainable development in the Boggo Road Busway Plan in Brisbane, Australia against the sustainability agenda set in the South East Queensland Regional and Transport Plans. Although the construction of the Busway was intended to improve public transport access in the region, its implementation drew significant environmental concerns. Local community groups contested the sustainability concept deployed in Queenslands infrastructure planning. Their challenges resulted in important concessions in the delivery of the Busway plan. This case demonstrates that principles of sustainable infrastructure should be measurable and that local communities be better informed in order to fulfill the public interest in regional planning. Document type: Part of book or chapter of book
Abstract
Sustainable infrastructure demands that declared principles of sustainability are enacted in the processes of its implementation. However, a problem arises if the concept [...]
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Mobilitätsverhalten der Wohnbevölkerung in Abhängigkeit von der Zentralität des Ortes
H. Mitter

Collection of open chapters of books in transport research (2011). Vol. 2011, 26

Abstract
Der Beitrag analysiert die Wechselwirkungen der Zentralität eines Ortes mit der Alltagsmobilität im Bundesland Oberösterreich. Für die im Oberösterreichischen Landesraumordnungsprogramm festgelegten Zentralitätsstufen wird auf Basis der Oberösterreichischen Verkehrserhebung das Mobilitätsverhalten der Wohnbevölkerung ab sechs Jahren an einem typischen Werktag näher betrachtet. Die Untersuchung zeigt, dass sich räumliche Strukturen auf den Anteil der Binnenwege an der Gesamtwegezahl, auf die mittlere Wegehäufigkeit pro Person und Tag und auf die Verkehrsmittelwahl auswirken. Hingegen verhält sich die Verteilung der Wegzwecke in allen Zentralitätsstufen sehr ähnlich. The article in hand analyses the interrelation between the centrality of a place and the traffic behaviour of its residents in everyday life. The evaluation is conducted for the province of Upper Austria which is situated in the northwest of Austria. The Upper Austrian Planning Programme determines four levels of centrality. For each level the traffic behaviour of the residents being six years of age and over is analysed for an average workday. The evaluation is based on the Upper Austrian Mobility Survey and shows that existing spatial structures affect the number of trips per person per day, the number of internal trips as well as the modal split. The purposes of the trips are similar within all levels of centrality. Document type: Book
Abstract
Der Beitrag analysiert die Wechselwirkungen der Zentralität eines Ortes mit der Alltagsmobilität im Bundesland Oberösterreich. Für die im Oberösterreichischen Landesraumordnungsprogramm [...]
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Assessing urban transportation development sustainable transportation perspectives for istanbul turkey
A. Tezer, C. Caliskan, M. Calik, S. Sinmaz

Collection of open chapters of books in transport research (2010). Vol. 2010, 21

Abstract
UN Population Revisions indicate that more than 50% of the worlds population has lived in urban areas since 2008 and much of the future urban population increase will be absorbed more by the few metropolitan areas of rapidly growing developing countries (UN, 2008). Due to the accelerated urban growth and uncontrolled urban dispersion through naturally significant peripheral areas, sustainable urban growth management becomes a critical urban development policy in Istanbul. In this respect, the interaction among urban growth, urban transportation, rational land use allocations and sustainable transportation policies has an important role to achieve more sustainable urban development in Istanbul. Istanbul set a unique example of urban spatial development/urban transportation interaction with Bosphorus bridges and the connecting highways. This chapter first addresses urban spatial dispersion and transportation development interaction with special emphasis on the existing and proposed Bosphorus Bridges, and then correlates the results with the recent Transportation Master Plan and Environmental Master Plan. Although the latest Environmental Master Plan prepared by Istanbul Metropolitan Municipality foresights the progression of public transit systems and no third bridge crossing on Bosphorus, there is a top-down impact for the third bridge crossing and a road tunnel on Bosphorus by the Central Government. Due to the interaction among spatial dispersion, transportation development and existing infrastructure, proposed bridges, their connected highways and flyovers as well as recent transportation investments of the Istanbul Metropolitan Municipality are assessed under the light of sustainable urban transportation policies. Document type: Part of book or chapter of book
Abstract
UN Population Revisions indicate that more than 50% of the worlds population has lived in urban areas since 2008 and much of the future urban population increase [...]
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ATM Systems and Wind Farms
A. Novak

Collection of open chapters of books in transport research (2010). Vol. 2010, 20

Abstract
All radars are different (even if only due to the physical impacts of their operating locations) and creating a ‘rule of thumb’ for wind farm developments near all systems would require such a level of generalisation as to make it probably worthless. Therefore, in considering the effect of wind turbines on radar, developers need to focus on individual radars in the vicinity of their planned development. It is important also that developers appreciate the nature and extent of any problem. (Novak, 2009) For example, studies into air defence radars that take no account of the associated Command and Control systems may be of very limited value. Because both civil and military aviation communities have legitimate interests that must be protected; this includes protection against the adverse effects of wind turbines. However, there is scope for flexibility throughout the process of considering wind farm applications. Document type: Part of book or chapter of book
Abstract
All radars are different (even if only due to the physical impacts of their operating locations) and creating a ‘rule of thumb’ for wind farm developments near all systems [...]
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Energie, Klima, Raum. Wie lässt sich Mobilität sinnvoll steuern? Einführung
Y. Knapstein, M. Schmidt

Collection of open chapters of books in transport research (2011). Vol. 2011, 20

Abstract
Document type: Book
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Industry regulation through open source software a strategic ownership proposal
J. Hardy

Collection of open chapters of books in transport research (2010). Vol. 2010, 19

Abstract
International audience; This paper is about a twofold proposal submitted to the scrutiny of the OSS scientific community. It is first argued that OSS should be considered a means to establish an industry regulation. The motivation of this first proposal is the need for harmonization of the supply chain in certain industrial sectors. The Air Traffic Management industry (ATM) is the only case considered in this paper. However, it is assumed that the regulatory advantage of OSS is not specific to that industry. The second proposal is about how to establish such a regulation through OSS. It is argued that the legal ownership of the OSS product should be assigned to a public organization, preferably to an organization that would be dedicated to monitor and promote the evolution of that product. The motivation for these proposals is based on the analysis of possible scenarios of OSS ownership in the case of ATM. Perspectives concerning the preliminary implementation of the proposals are introduced. Document type: Part of book or chapter of book
Abstract
International audience; This paper is about a twofold proposal submitted to the scrutiny of the OSS scientific community. It is first argued that OSS should be considered [...]
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Intelligent editor for writing worst case execution time oriented programs
J. Fauster, R. Kirner, P. Puschner

Collection of open chapters of books in transport research (2010). Vol. 2010, 18

Abstract
To guarantee timeliness in hard real-time systems the knowledge of the worst-case execution time (WCET) for its time-critical tasks is mandatory. Accurate and correct WCET analysis for modern processor is a quite complex problem. Path analysis is required to identify a minimal set of possible execution paths. Further, the modeling of a processors internal states for features like caches or pipelines requires to consider possible interferences of these features. Document type: Part of book or chapter of book
Abstract
To guarantee timeliness in hard real-time systems the knowledge of the worst-case execution time (WCET) for its time-critical tasks is mandatory. Accurate and correct WCET [...]
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Safety, Efficiency and Autonomy - Mastering Conflicting Trends in Embedded Systems Design
R. Ernst

Collection of open chapters of books in transport research (2010). Vol. 2010, 17

Abstract
International audience; Embedded systems have developed from single microcontrollers to networked sys-tems and are moving further on to large open systems. As an example, automotive electronics started as a single microcontroller for engine control to develop into a local network of 50 and more electronic control units connected via several network standards and gateways which are found in current cars. These networks will be ex-tended by open wireless car-to-car or car-to-infrastructure communication enabling completely new functionality, such as advanced driver assistance systems that report approaching cars that could cause an accident. Other examples are found in health-care, where patients are monitored at home connected to a hospital data base and monitoring system rather than staying in the hospital for that purpose, or in smart buildings where different control functions are integrated to minimize energy con-sumption and adapt consumption to the available energy, or in energy supply net-works that are optimized to include renewable energy production. In all these cases we observe a transition from local closed networks with a single systems integrator controlling all design aspects (such as an automotive manufacturer) to larger open networks with many independent functions and different integrators following differ-ent design objectives. The Internet plays an important role supporting that trend. Unlike closed networks with a defined topology, such systems change over the life-time of a system. Document type: Part of book or chapter of book
Abstract
International audience; Embedded systems have developed from single microcontrollers to networked sys-tems and are moving further on to large open systems. As an example, [...]
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A Fair Bulk Data Transmission Protocol in Grid Environments
F. Su, X. Pan, Y. lv, L. Ping

Collection of open chapters of books in transport research (2010). Vol. 2010, 16

Abstract
In this paper, we propose FHSTCP (Fair High-Speed TCP) as an improvement of HSTCP, which adds a fair factor to eliminate the difference of congestion window caused by different RTT and adopts block-pacing to reduce the burstiness. Simulation results show that FHSTCP can alleviate the RTT unfairness meanwhile keeping advantages of HSTCP. Document type: Part of book or chapter of book
Abstract
In this paper, we propose FHSTCP (Fair High-Speed TCP) as an improvement of HSTCP, which adds a fair factor to eliminate the difference of congestion window caused by different [...]
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Using Smartphones to Detect Car Accidents and Provide Situational Awareness to Emergency Responders
C. Thompson, J. White, B. Dougherty, A. Albright, D. Schmidt

Collection of open chapters of books in transport research (2010). Vol. 2010, 14

Abstract
Accident detection systems help reduce fatalities stemming from car accidents by decreasing the response time of emergency responders. Smartphones and their onboard sensors (such as GPS receivers and accelerometers) are promising platforms for constructing such systems. This paper provides three contributions to the study of using smartphone-based accident detection systems. First, we describe solutions to key issues associated with detecting traffic accidents, such as preventing false positives by utilizing mobile context information and polling onboard sensors to detect large accelerations. Second, we present the architecture of our prototype smartphone-based accident detection system and empirically analyze its ability to resist false positives as well as its capabilities for accident reconstruction. Third, we discuss how smartphone-based accident detection can reduce overall traffic congestion and increase the preparedness of emergency responders. Document type: Part of book or chapter of book
Abstract
Accident detection systems help reduce fatalities stemming from car accidents by decreasing the response time of emergency responders. Smartphones and their onboard sensors [...]
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Pma supplier selection using the mahalanobis taguchi system
T. Wong

Collection of open chapters of books in transport research (2010). Vol. 2010, 13

Abstract
Most hi-tech industries owe at least some of their success to being in the right place at the right time. This is especially true for the aircraft parts manufacturer approval (PMA) industry. A PMA is both a design approval and a production approval. It is issued for the production of modification or replacement parts for aircraft, which includes materials, parts, processes, and appliances. In the current economic climate, airlines throughout the world are looking for partners with financial stability. The reason is simple, they want partners that will continue to support them with extra savings opportunities in the short and long-term future. As more and more PMA companies are advertising through the Internet, a supplier performance measurement model applying to each of these networked organizations will facilitate the airline selection of long-term PMA partners. In this chapter, the Mahalanobis Taguchi System (MTS) approach, a multivariate data based selection system, will be used to identify the promising PMA suppliers. Suppliers who are known to be promising are called promising groups and their performance data sets are used to create a reference metric for the promising PMA supplier population. In view of the synergetic performance of neural network and data mining technologies, it is expected that this MTS-based PMA partner selection method, implementing through a neural data mining system (NDMS) will provide a practical solution in the identification of the promising PMA suppliers. Document type: Part of book or chapter of book
Abstract
Most hi-tech industries owe at least some of their success to being in the right place at the right time. This is especially true for the aircraft parts manufacturer approval [...]
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Schneller, öfter, weiter? Perspektiven der Raumentwicklung in der Mobilitätsgesellschaft. Einführung
H. Hege, R. Meng, A. Schmitz-Veltin

Collection of open chapters of books in transport research (2011). Vol. 2011, 15

Abstract
Document type: Book
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Analysis of recipient executed trust funds
W. Huq

Collection of open chapters of books in transport research (2010). Vol. 2010, 12

Abstract
In recent years, bilateral aid channeled through multilateral organizations like the World Bank has become an important vehicle for concessional finance for development. At the end of FY09, the World Bank held US$23.9 billion in trust, an amount that has doubled since FY05. While much of the growth reflects the increase in large Financial Intermediary Funds (FIFs), there has also been a rapid increase in Recipient Executed Trust Funds (RETFs). This paper aims to inform internal Bank audiences and stimulate discussion on some selected issues - primarily the growing importance of RETFs as a source of finance and relevance to Bank's country level operations. The report also examines briefly the link between RETF allocations and country performance. The report finds that disbursements of RETFs grew by twenty percent over FY03-FY09. Over this period the trends in regional disbursement shares shifted away from East Asia and Pacific and South Asia Regions to Africa Region. Recipient country concentration is evident: fifty percent of the disbursements have been from six countries - Afghanistan, West Bank and Gaza, Ethiopia, Vietnam, Indonesia and China. RETF disbursements, as a share of the combined International Bank for Reconstruction and Development (IBRD), International Development Association (IDA), and RETF, grew from five percent in FY03 to twelve percent in FY08, while that of IBRD and IDA fluctuated. The bulk of the disbursements from RETF grants were from IDA eligible countries. RETFs appear to have substituted for IDA in fragile and conflict affected states. Disbursements from RETF grants and IDA credits were broadly aligned by sector. There may be some correlation between RETF grants allocation and country performance but the results are not conclusive. The report identifies some areas for further examination: whether RETFs should complement or substitute for Bank operations in specific cases; and whether RETF allocations should be made on the basis of some need or performance based country priorities, outcomes and results. Document type: Book
Abstract
In recent years, bilateral aid channeled through multilateral organizations like the World Bank has become an important vehicle for concessional finance for development. At [...]
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Richard branson screw it let s do it
R. Butler

Collection of open chapters of books in transport research (2010). Vol. 2010, 11

Abstract
Document type: Part of book or chapter of book
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On the Performance of Grooming Strategies for Offloading IP Flows onto Lightpaths in Hybrid Networks
R. Biesbroek, T. Fioreze, L. Granville, A. Pras

Collection of open chapters of books in transport research (2010). Vol. 2010, 10

Abstract
International audience; Hybrid networks take data forwarding decisions at multiple network levels. In order to make an efficient use of hybrid networks, traffic engineering solutions (e.g., routing and data grooming techniques) are commonly employed. Within the specific context of a self-managed hybrid optical and packet switching network, one important aspect to be considered is how to efficiently and autonomically move IP flows from the IP level over lightpaths at the optical level. The more IP traffic is moved (offloaded), leaving the least amount of traffic on the IP level, the better. Based on that, we investigate in this paper different strategies to move IP flows onto lightpaths while observing the percentage of offloaded IP traffic per strategy. Document type: Part of book or chapter of book
Abstract
International audience; Hybrid networks take data forwarding decisions at multiple network levels. In order to make an efficient use of hybrid networks, traffic engineering [...]
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Interdomain ingress traffic engineering through optimized as path prepending
R. Gao, C. Dovrolis, E. Zegura

Collection of open chapters of books in transport research (2010). Vol. 2010, 9

Abstract
In INterdomain Ingress Traffic Engineering (INITE), a “target” Autonomous System (AS) aims to control the ingress link at which the traffic of one or more upstream source networks enters that AS. In practice, ISPs often manipulate, mostly in a trial-and-error manner, the length of the AS-Path attribute of upstream routes through a simple technique known as prepending (or padding). In this paper, we focus on prepending and propose a polynomial-time algorithm (referred to as OPV) that determines the optimal padding for an advertised route at each ingress link of the target network. Specifically, given a set of “elephant” source networks and some maximum load constraints on the ingress links of the target AS, OPV determines the minimum padding at each ingress link so that the load constraints are met, when it is feasible to do so. OPV requires as input an AS-Path length estimate from each source network to each ingress link. We describe how to estimate this matrix, leveraging the BGP Looking Glass Servers. To deal with unavoidable inaccuracies in the AS-Path length estimates, and also to compensate for the generally unknown BGP tie-breaking process in upstream networks, we also develop a robust variation (RPV) of the OPV algorithm. Document type: Part of book or chapter of book
Abstract
In INterdomain Ingress Traffic Engineering (INITE), a “target” Autonomous System (AS) aims to control the ingress link at which the traffic of one or more upstream source [...]
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Cooperative content distribution scalability through self organization
P. Felber, E. Biersack

Collection of open chapters of books in transport research (2010). Vol. 2010, 8

Abstract
Peer-to-peer networks have often been touted as the ultimate solution to scalability. Although cooperative techniques have been initially used almost exclusively for content lookup and sharing, one of the most promising application of the peer-to-peer paradigm is to capitalize the bandwidth of client peers to quickly distribute large content and withstand flash-crowds (i.e., a sudden increase in popularity of some online content). Cooperative content distribution is based on the premise that the capacity of a network is as high as the sum of the resources of its nodes: the more peers in the network, the higher its aggregate bandwidth, and the better it can scale and serve new peers. Such networks can thus spontaneously adapt to the demand by taking advantage of available resources. In this paper, we evaluate the use of peer-to-peer networks for content distribution under various system assumptions, such as peer arrival rates, bandwidth capacities, cooperation strategies, or peer lifetimes. We argue that the self-scaling and self-organizing properties of cooperative networks pave the way for cost-effective, yet highly efficient and robust content distribution. Document type: Part of book or chapter of book
Abstract
Peer-to-peer networks have often been touted as the ultimate solution to scalability. Although cooperative techniques have been initially used almost exclusively for content [...]
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A transition towards sustainable strategy making: integrating land use and transport knowledge types
M. te Brömmelstroet, L. Bertolini, J. van Nunen, P. Huijbregts, P. Rietveld

Collection of open chapters of books in transport research (2011). Vol. 2011, 9

Abstract
As extensively discussed by other scholars, there is a growing awareness that the integration of land use and transport (LUT) planning is a crucial prerequisite for the transition towards more sustainable transport patterns and urban development that foster interaction between people, support a sustainable business climate and reduces negative effects on the environment and climate (see, for example, Banister 2002, 2005; Cervero 1998; Meyer and Miller 2001; TRB 2004). However, in the Netherlands (and in other countries), such integration is scarcely present in daily planning practice (see, for instance, Hull and Tricker 2006). If anything, one can speak of policy coordination rather than ‘integration’; i.e. it is dialogue or information exchange which is geared at avoiding conflicts between projects, but does not seek to establish similar policy goals (Stead et al. 2004). Achieving integration in earlier phases of planning (for example, strategy development, goal orientation or visioning) can potentially produce shared policy goals, which would promote mutually reinforcing (instead of obstructing) land use and transport measures. However, for this to happen, a transition on its own is needed. Document type: Part of book or chapter of book
Abstract
As extensively discussed by other scholars, there is a growing awareness that the integration of land use and transport (LUT) planning is a crucial prerequisite for the transition [...]
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Internationalisation and mobility in european vocational education and training : international report
R. Egetenmeyer, S. Rueffin, A. Blachnio

Collection of open chapters of books in transport research (2011). Vol. 2011, 8

Abstract
The international report is an outcome of the European Leonardo da Vinci project Internationalisation and Mobility in the students Curricula (INtheMC) carried out with eight partners from seven European countries. It analyses the situation of internationalisation and transnational mobility in vocational education and training (VET) in Europe. After outlining the initial situation the situation of VET in the partner countries the report shows the current situation and trends of internationalisation and mobility within VET. Then European instruments (Europass Mobility, EQF, ECVET), which promotes internationalisation and mobility in VET are presented also concerning the actual state of implementation in the partner countries. Following this, several available researches on target groups are displayed. Examples from best practice and obstacles are shown. Then the question is asked and in part answered: how to improve internationalisation and educational mobility in order to obtain desired outcomes in VET? The report ends with conclusions and proposals for promoting internationalisation and mobility in VET. (Orig.) Document type: Book
Abstract
The international report is an outcome of the European Leonardo da Vinci project Internationalisation and Mobility in the students Curricula (INtheMC) carried out with eight [...]
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Valuation of Ecosystem Services in World Bank Group Work
G. Lange, A. Belle, S. Kishore

Collection of open chapters of books in transport research (2010). Vol. 2010, 4

Abstract
In 2005, the Millennium Ecosystem Assessment (MA, 2005) provided the first comprehensive report on global ecosystems, the dependence of human societies on the services provided, current state, and likely future trajectory. The MA identified the failure to value ecosystem services as a major contributing cause. The 2001 environment strategy did not explicitly address environmental valuation, although the focus on poverty and environment implies a need for valuing natural resources and environmental services. In consultations on the 2010 environment strategy, a wide range of stakeholders stressed the importance of mainstreaming environmental services. To better direct limited resources for environmental valuation and training, a closer look is needed to identify the conditions under which valuation has had an impact on: policy and project design, policy dialogue in client countries, environmental investments, and strengthening the capacity of national institutions. This report presents a review of environmental valuation in World Bank operational and analytical work, identifying what has been done, and the impacts environmental valuation has had. The report identifies the conditions under which valuation is most likely to influence decision-makers, and finally, the implications for the 2010 environment strategy. The report is organized as follows: section one gives context; section two gives introduction; section three gives approach to learning from past experience; section four focuses on coverage of ecosystem services; section five presents prioritizing environmental valuation; section six deals with why environmental valuation not done; and section seven gives recommendations. Document type: Book
Abstract
In 2005, the Millennium Ecosystem Assessment (MA, 2005) provided the first comprehensive report on global ecosystems, the dependence of human societies on the services provided, [...]
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Modeling control system failures and attacks the waterloo campaign to oil pipelines
J. Butts, M. Rice, S. Shenoi

Collection of open chapters of books in transport research (2010). Vol. 2010, 3

Abstract
This paper presents a model for expressing control system failures and attacks on control protocols that involve the exchange of messages. Control failures and attacks are modeled using the notion of an attacker who can block and/or fabricate messages. These two attack mechanisms can cover a variety of scenarios ranging from control failures in the Waterloo Campaign to cyber attacks on oil pipelines. The model helps provide a comprehensive understanding of control system failures and attacks, which supports the development of strategies for attack as well as defense. Document type: Part of book or chapter of book
Abstract
This paper presents a model for expressing control system failures and attacks on control protocols that involve the exchange of messages. Control failures and attacks are [...]
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Responsabilidad social
J. Viteri Moya

Enfoque UTE - Scientific Engineering Journal (2010). Vol. 1, (4), 49

Abstract
Español:En
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Estructuración del precio de un menú
R. Baldeón Dávalos

Enfoque UTE - Scientific Engineering Journal (2010). Vol. 1, (4), 48

Abstract
Español:El
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Sistema de navegación automática controlada por voz para una silla de ruedas
M. Arévalo Luzuriaga

Enfoque UTE - Scientific Engineering Journal (2010). Vol. 1, (4), 47

Abstract
Español:El
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Modelo de contaminación del aire
I. Naula

Enfoque UTE - Scientific Engineering Journal (2010). Vol. 1, (4), 46

Abstract
El
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La basura electrónica y la contaminación ambiental
L. Hidalgo Aguilera

Enfoque UTE - Scientific Engineering Journal (2010). Vol. 1, (4), 45

Abstract
Español:En
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Embutidos fortificados con proteína vegetal a base de quinua (Chenopodium quinoa Wild.)
P. Maldonado

Enfoque UTE - Scientific Engineering Journal (2010). Vol. 1, (4), 44

Abstract
Español:El
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Optimización de la geometría de la bomba hidráulica tipo jet
V. Melo

Enfoque UTE - Scientific Engineering Journal (2010). Vol. 1, (4), 43

Abstract
Español:Este
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Influencia del tratamiento UV-C sobre carambola (Averrhoa carambola L.) mínimamente procesada
M. Andrade, C. Moreno Guerrero

Enfoque UTE - Scientific Engineering Journal (2010). Vol. 1, (4), 42

Abstract
Español:La
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Possibilities of the Particle Finite Element Method in computational mechanics
E. Oñate, S. Idelsohn, M. Celigueta, R. Rossi, S. Latorre

(2010). Computer Methods in Mechanics, M. Kuzma, K. Wilmanski (Eds.), Chapter 15, pp. 271-310., Springer-Verlag, Berlin, Heidelberg

Abstract
We present some developments in the formulation of the Particle Finite Element Method (PFEM) for analysis of complex coupled problems in fluid and solid mechanics accounting for fluid-structure interaction and coupled thermal effects. The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in both the fluid and the structure domains. Nodes are viewed as material points which can freely move and even separate from the main analysis domain representing, for instance, the effect of water drops. A mesh connects the nodes defining the discretized domain where the governing equations are solved as in the standard FEM. The necessary stabilization for dealing with the incompressibility of the fluid is introduced via the finite calculus (FIC) method. An incremental iterative scheme for the solution of the non linear transient coupled fluid-structure problem is described. Extensions of the PFEM to allow for frictional contact conditions at fluid-solid and solid-solid interfaces via mesh generation are described. A simple algorithm to treat erosion in the fluid bed is presented. Examples of application of the PFEM to solve a number of coupled problems such as the effect of large wave on structures, the large motions of floating and submerged bodies, bed erosion situations and melting and dripping of polymers under the effect of fire are given.
Abstract
We present some developments in the formulation of the Particle Finite Element Method (PFEM) for analysis of complex coupled problems in fluid and solid mechanics accounting [...]
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An error estimator for separated representations of highly multidimensional models
A. Ammar, F. Chinesta, P. Diez, A. Huerta

Comput. Methods Appl. Mech. Engrg., (2010). Vol. 199 (25-28), pp. 1872-1880

Abstract
Fine modeling of the structure and mechanics of materials from the nanometric to the micrometric scales uses descriptions ranging from quantum to statistical mechanics. Most of these models consist of a partial differential equation defined in a highly multidimensional domain (e.g. Schrodinger equation, Fokker-Planck equations among many others). The main challenge related to these models is their associated curse of dimensionality. We proposed in some of our former works a new strategy able to circumvent the curse of dimensionality based on the use of separated representations (also known as finite sums decomposition). This technique proceeds by computing at each iteration a new sum that consists of a product of functions each one defined in one of the model coordinates. The issue related to error estimation has never been addressed. This paper presents a first attempt on the accuracy evaluation of such a kind of discretization techniques.
Abstract
Fine modeling of the structure and mechanics of materials from the nanometric to the micrometric scales uses descriptions ranging from quantum to statistical mechanics. Most [...]
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Strict error bounds for linear and nonlinear solid mechanics problems using a patch-based flux-free method
R. Cottereau, L. Chamoin, P. Diez

Mécanique & Industries (2010). Vol. 11 (3-4), pp. 249-254

Abstract
We discuss, in this paper, a common flux-free method for the computation of strict error bounds for linear and nonlinear Finite Element computations. In the linear case, the error bounds are on the energy norm of the error, while, in the nonlinear case, the concept of error in constitutive relation is used. In both cases, the error bounds are strict in the sense that they refer to the exact solution of the continuous equations, rather than to some FE computation over a refined esh. For both linear and nonlinear solid mechanics, this method is based on the computation of a statically admissible stress field, which is performed as a series of local problems on patches of elements
Abstract
We discuss, in this paper, a common flux-free method for the computation of strict error bounds for linear and nonlinear Finite Element computations. In the linear case, the [...]
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Error estimation and quality control
P. Diez, N. Parés, A. Huerta

Encyclopedia of Aerospace Engineering (2010). Vol. 3 (15), pp. 1725-1734

Abstract
This chapter provides a description of the error assessment tools available for general finite element analysis, in particular those for solid and structural mechanics. The text focuses on goal-oriented error estimation, in terms of general quantities of interest rather than on energy norm. However, the energy norm estimates are also discussed because they are seen as basic tools that must be used for assessing the error in arbitrary functional outputs of the solution. Attention is paid to the classification of the different methodologies and their main characteristics.
Abstract
This chapter provides a description of the error assessment tools available for general finite element analysis, in particular those for solid and structural mechanics. The [...]
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A flux-free a posteriori error estimator for the incompressible Stokes problem using a mixed FE formulation
F. Larsson, P. Diez, A. Huerta

Comput. Methods Appl. Mech. Engrg., (2010). Vol. 199 (37-40), pp. 2383-2402

Abstract
In this contribution, we present an a posteriori error estimator for the incom- pressible Stokes problem valid for a conventional mixed FE formulation. Due to the saddle-point property of the problem, conventional error estimators de- veloped for pure minimization problems cannot be utilized straight-forwardly. The new estimator is built up by two key ingredients. At first, a computed error approximation, exactly fulfilling the continuity equation for the error, is obtained via local Dirichlet problems. Secondly, we adopt the approach of solving local equilibrated flux-free problems in order to bound the remaining, incompressible, error. In this manner, guaranteed upper and lower bounds, of the velocity ”energy norm” of the error as well as goal-oriented (linear) output functionals, with respect to a reference (overkill) mesh are obtained. In particular, it should be noted that this approach requires no computa- tion of hybrid fluxes. Furthermore, the estimator is applicable to mixed FE formulations using continuous pressure approximations, such as the Mini and Taylor-Hood class of elements. In conclusion, a few simple numerical examples are presented, illustrating the accuracy of the error bounds.
Abstract
In this contribution, we present an a posteriori error estimator for the incom- pressible Stokes problem valid for a conventional mixed FE formulation. Due to the saddle-point [...]
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Modeling, with a unified level-set representation, of the expansion of a hollow in the ground under different physical phenomena
R. Cottereau, P. Diez, A. Huerta

Computational Mechanics (2010). Vol. 46 (2), pp. 315-327

Abstract
This paper builds on the flexibility of the level-set representation to model in a unified manner the expansion of a hollow in the ground under different physical phenomena. In particular, the dissolving action of a flow of water in a saturated soil, and that of a jet of particles of water in a non-saturated one, are represented in a common framework. In that manner, the complex geometrical evolutions of the hollow can be followed without the need for remeshing and this approach allows for a smooth transition between saturated and non-saturated models of the soil. Implementation and numerical difficulties are discussed and two applications of industrial interest are considered. The first one describes the modeling of the piping phenomenon, and the second one the evolution of an excavation created by a leaking duct.
Abstract
This paper builds on the flexibility of the level-set representation to model in a unified manner the expansion of a hollow in the ground under different physical phenomena. [...]
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Accurate recovery-based upper error bounds for the extended finite element framework
J. Ródenas, A. Estrada, P. Diez, F. Fuenmayor

Comput. Methods Appl. Mech. Engrg., (2010). Vol. 199, pp. 2607-2621

Abstract
This paper introduces a recovery-type error estimator yielding upper bounds of the error in energy norm for linear elastic fracture mechanics problems solved using the extended finite element method (XFEM). The paper can be considered as an extension and enhancement of a previous work in which the upper bounds of the error were developed in a FEM framework. The upper bound property requires the recovered solution to be equilibrated and continuous. The proposed technique consists of using a recovery technique, especially adapted to the XFEM framework that yields equilibrium at a local level (patch by patch). Then a postprocess based on the partition of unity concept is used to obtain continuity. The result is a very accurate but only nearly-statically admissible recovered stress field, with small equilibrium defaults introduced by the postprocess. Sharp upper bounds are obtained using a new methodology accounting for the equilibrium defaults, as demonstrated by the numerical tests.
Abstract
This paper introduces a recovery-type error estimator yielding upper bounds of the error in energy norm for linear elastic fracture mechanics problems solved using the extended [...]
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SUPG-based stabilization using a separated representations approach
D. Gonzalez, L. Debeugny, E. Cueto, F. Chinesta, P. Diez, A. Huerta

Int. J. of Material Forming (2010). Vol. 3 (1), pp. 883-886

Abstract
We have developed a new method for the construction of Streamline Upwind Petrov Galerkin (SUPG) stabilization techniques for the resolution of convection-diffusion equations based on the use of separated representations inside the Proper Generalized Decompositions (PGD) framework. The use of SUPG schemes produces a consistent stabilization adding a parameter to all the terms of the equation (not only the convective one). SUPG obtains an exact solution for problems in 1D, nevertheless, a generalization does not exist for elements of high order or for any system of convection-diffusion equations. We introduce in this paper a method that achieves stabilization in the context of Proper Generalzied Decomposition (PGD). This class of approximations use a representation of the solution by means of the sum of a finite number of terms of separable functions. Thus it is possible to use the technique of separation of variables in the context of problems of convection-diffusion that will lead to a sequence of problems in 1D where the parameter of stabilization is well known.
Abstract
We have developed a new method for the construction of Streamline Upwind Petrov Galerkin (SUPG) stabilization techniques for the resolution of convection-diffusion equations [...]
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Error assessment and mesh adaptivity for regularized continuous failure models
T. Pannachet, P. Diez, H. Askes, L. Sluys

Comput. Methods Appl. Mech. Engrg., (2010). Vol. 199 (17-20), pp. 961-978

Abstract
This paper deals with the adaptive finite element analysis of structural failure. A gradient-enhanced damage model has been chosen to simulate material degradation. Since this model is regularized in the post-peak regime, the finite element solution does not suffer from pathological mesh dependence and thus converges to an objective solution upon mesh refinement. However, the error analyses have shown that the error in the nonlocal equivalent strain field becomes dominant during the postpeak loading stages. The accuracy of the nonlocal equivalent strain field (and the corresponding damage quantity) also greatly influences the accuracy of the quantity of interest. Two error measures have been proposed. The goal-oriented error estimates have provided similar error distributions, although some small differences have been found in the softening regime. Objective error estimates, together with adaptive criteria, have been used to perform automated h-adaptivity during computation.
Abstract
This paper deals with the adaptive finite element analysis of structural failure. A gradient-enhanced damage model has been chosen to simulate material degradation. Since [...]
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Assembling sparse matrices in MATLAB
S. Zlotnik, P. Diez

Commun. Numer. Meth. Engng (2010). Vol. 26 (6), pp. 760-769

Abstract
The assembly of sparse matrices is a key operation in finite element methods. In this study we analyze several factors that may have an influence on the efficiency of the assembly procedure. Different insertion strategies are compared using two metrics: a Cost function (the number of memory movements) and actual computing time. An improved algorithm implemented in MATLAB is proposed. It reduces both memory operations and computing time for all tested cases. The efficiency of the assembly process is found to be highly dependent on node and element numbering. The effect of the classic reverse Cuthill–McKee algorithm is, in most cases, positive and reduces computation costs. Finally, the case where a sparse matrix has to be re‐assembled at each time step is studied. The efficiency of the assembly is improved if the matrix pattern is entirely or partially inherited from previous steps.
Abstract
The assembly of sparse matrices is a key operation in finite element methods. In this study we analyze several factors that may have an influence on the efficiency of the [...]
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Thermal coupling of fluid and structural response of a tunnel induced by fire
B. Schrefler, R. Codina, F. Pesavento, J. Principe

Int. J. Numer. Meth. Engng. (2010). Vol. 87 (1-5), pp. 361-385

Abstract
In this work we present the progress in the development of an algorithm for the simulation of thermal fluid–structural coupling in a tunnel fire. The coupling strategy is based on a Dirichlet/Neumann non‐overlapping domain decomposition of the problem, which is carried out by developing a master code that controls solvers dedicated to the fluid mechanics and to the solid mechanics simulation. The computational fluid dynamics formulation consists of a stabilized finite element approximation of the low Mach number equations based on the subgrid scale concept, that allows us to deal with convection‐dominated problems and to use equal order interpolation of velocity and pressure. The thermo‐structural model of the tunnel vault, that considers a multiphase porous material where pores are partly filled with liquid and partly by gas, is specially devised for the simulation of concrete at high temperatures and consists of balance equations for mass conservation of dry air, mass conservation of water species (both in the liquid and gaseous state), enthalpy conservation and linear momentum conservation taking phase changes into account. The developed algorithm is applied to the problem of the response of a tunnel to a fire. We consider the combustion process as a heat release which can vary usually from 1thinspaceMW for small car fires to 100 MW for catastrophic fires. The released heat is transferred to the concrete walls of the tunnel which could cause extensive and heavy damage of the structure.
Abstract
In this work we present the progress in the development of an algorithm for the simulation of thermal fluid–structural coupling in a tunnel fire. The coupling [...]
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Long-term stability estimates and existence of a global attractor in a finite element approximation of the Navier-Stokes equations with numerical sub-grid scale modeling
S. Badia, R. Codina, J. Gutiérrez-Santacreu

SIAM J. Numer. Anal. (2010). Vol. 48 (3), pp. 1013-1037

Abstract
Variational multiscale methods lead to stable finite element approximations of the NavierStokes equations, both dealing with the indefinite nature of the system (pressure stability) and the velocity stability loss for high Reynolds numbers. These methods enrich the Galerkin formulation with a sub-grid component that is modelled. In fact, the effect of the sub-grid scale on the captured scales has been proved to dissipate the proper amount of energy needed to approximate the correct energy spectrum. Thus, they also act as effective large-eddy simulation turbulence models and allow to compute flows without the need to capture all the scales in the system. In this article, we consider a dynamic sub-grid model that enforces the sub-grid component to be orthogonal to the finite element space in L 2 sense. We analyze the long-term behavior of the algorithm, proving the existence of appropriate absorbing sets and a compact global attractor. The improvements with respect to a finite element Galerkin approximation are the long-term estimates for the sub-grid component, that are translated to effective pressure and velocity stability. Thus, the stabilization introduced by the sub-grid model into the finite element problem is not deteriorated for infinite time intervals of computation.
Abstract
Variational multiscale methods lead to stable finite element approximations of the NavierStokes equations, both dealing with the indefinite nature of the system (pressure [...]
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Finite element approximation of turbulent thermally coupled incompressible flows with numerical sub-grid scale modeling
R. Codina, J. Principe, M. Ávila

Int. J. Numer. Meth. Heat and Fluid Flow (2010). Vol. 20 (5), pp. 492-516

Abstract
The objective of this work is to describe a variational multiscale finite element approximation for the incompressible Navier-Stokes equations using the Boussinesq approximation to model thermal coupling. The main feature of the formulation in contrast to other stabilized methods is that we consider the subscales as transient and orthogonal to the finite element space. These subscales are solution of a differential equation in time that needs to be integrated. Likewise, we keep the effect of the subscales both in the nonlinear convective terms of the momentum and temperature equations and, if required, in the thermal coupling term of the momentum equation. This strategy allows us to approach the problem of dealing with thermal turbulence from a strictly numerical point of view and discuss important issues, such as the relationship between the turbulent mechanical dissipation and the turbulent thermal dissipation
Abstract
The objective of this work is to describe a variational multiscale finite element approximation for the incompressible Navier-Stokes equations using the Boussinesq approximation [...]
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Stabilized continuous and discontinuous Galerkin techniques for Darcy flow
S. Badia, R. Codina

Comput. Methods Appl. Mech. Engrg., (2010). vol. 199 (25-28), pp. 1654-1667

Abstract
We design stabilized methods based on the variational multiscale decomposition of Darcy's problem. A model for the subscales is designed by using a heuristic Fourier analysis. This model involves a characteristic length scale, that can go from the element size to the diameter of the domain, leading to stabilized methods with different stability and convergence properties. These stabilized methods mimic different possible functional settings of the continuous problem. The optimal method depends on the velocity and pressure approximation order. They also involve a subgrid projector that can be either the identity (when applied to finite element residuals) or can have an image orthogonal to the finite element space. In particular, we have designed a new stabilized method that allows the use of piecewise constant pressures. We consider a general setting in which velocity and pressure can be approximated by either continuous or discontinuous approximations. All these methods have been analyzed, proving stability and convergence results. In some cases, duality arguments have been used to obtain error bounds in the L2-norm.
Abstract
We design stabilized methods based on the variational multiscale decomposition of Darcy's problem. A model for the subscales is designed by using a heuristic Fourier analysis. [...]
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On the stabilization parameter in the subgrid scale approximation of scalar convection–diffusion–reaction equations on distorted meshes
J. Principe, R. Codina

Comput. Methods Appl. Mech. Engrg., (2010). Vol. 199 (21-22), pp. 1386-1402

Abstract
In this paper we revisit the definition of the stabilization parameter in the finite element approximation of the convection–diffusion–reaction equation. The starting point is the decomposition of the unknown into its finite element component and a subgrid scale that needs to be approximated. In order to incorporate the distortion of the mesh into this approximation, we transform the equation for the subgrid scale within each element to the shape-regular reference domain. The expression for the subgrid scale arises from an approximate Fourier analysis and the identification of the wave number direction where instabilities are most likely to occur. The final outcome is an expression for the stabilization parameter that accounts for anisotropy and the dominance of either convection or reaction terms in the equation.
Abstract
In this paper we revisit the definition of the stabilization parameter in the finite element approximation of the convection–diffusion–reaction equation. The starting [...]
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The dissipative structure of variational multiscale methods for incompressible flows
J. Principe, R. Codina, F. Henke

Comput. Methods Appl. Mech. Engrg., (2010). Vol. 199 (13-16), pp. 791-801

Abstract
In this paper, we present a precise definition of the numerical dissipation for the orthogonal projection version of the variational multiscale method for incompressible flows. We show that, only if the space of subscales is taken orthogonal to the finite element space, this definition is physically reasonable as the coarse and fine scales are properly separated. Then we compare the diffusion introduced by the numerical discretization of the problem with the diffusion introduced by a large eddy simulation model. Results for the flow around a surface-mounted obstacle problem show that numerical dissipation is of the same order as the subgrid dissipation introduced by the Smagorinsky model. Finally, when transient subscales are considered, the model is able to predict backscatter, something that is only possible when dynamic LES closures are used. Numerical evidence supporting this point is also presented.
Abstract
In this paper, we present a precise definition of the numerical dissipation for the orthogonal projection version of the variational multiscale method for incompressible flows. [...]
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A numerical strategy to compute optical parameters in turbulent flow. Application to telescopes
R. Codina, J. Baiges, D. Pérez-Sánchez, M. Collados

Computers and Fluids (2010). Vol. 39 (1), pp. 87-98

Abstract
We present a numerical formulation to compute optical parameters in a turbulent air flow. The basic numerical formulation is a large eddy simulation (LES) of the incompressible Navier-Stokes equations, which are approximated using a finite element method. From the time evolution of the flow parameters we describe how to compute statistics of the flow variables and, from them, the parameters that determine the quality of the visibility. The methodology is applied to estimate the optical quality around telescope enclosures.
Abstract
We present a numerical formulation to compute optical parameters in a turbulent air flow. The basic numerical formulation is a large eddy simulation (LES) of the incompressible [...]
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A 3D low-order panel method for unsteady aerodynamic problems
E. Ortega, R. Flores, E. Oñate

(2010). Research Report, Nº PI343

Abstract
An unsteady low-order panel method for three-dimensional subsonic analyses is presented. The method, which is based on well-established techniques in computational aerodynamics, is intended to achieve a cost-effective solution of unsteady flows around arbitrary aerodynamic configurations. This work has two main objectives. First, to relax geometry discretization requirements and, second, to simplify the treatment of problems in which the analysis configuration moves along specified flight paths and/or changes its geometry during the simulation. Following this aim, a time-marching solution procedure is adopted in conjunction with a free-wake model which avoids iterative solutions for wake shape and position. The suitability of the present approach for solving typical aerodynamic problems is illustrated by means of several numerical examples.
Abstract
An unsteady low-order panel method for three-dimensional subsonic analyses is presented. The method, which is based on well-established techniques in computational aerodynamics, [...]
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Advances in the simulation of multi-fluid flows with the Particle Finite Element Method. Application to bubble dynamics
M. Mier-Torrecilla, S. Idelsohn, E. Oñate

(2010). Research Report, Nº PI342

Abstract
In this work we extend the Particle Finite Element Method (PFEM) to multi-fluid flow problems with the aim of exploiting the fact that Lagrangian methods are specially well suited for tracking interfaces. We develop a numerical scheme able to deal with large jumps in the physical properties, included surface tension, and able to accurately represent all types of discontinuities in the flow variables. The scheme is based on decoupling the velocity and pressure variables through a pressure segregation method which takes into account the interface conditions. The interface is defined to be aligned with the moving mesh, so that it remains sharp along time, and pressure degrees of freedom are duplicated at the interface nodes to represent the discontinuity of this variable due to surface tension and variable viscosity. Furthermore, the mesh is refined in the vicinity of the interface to improve the accuracy and the efficiency of the computations. We apply the resulting scheme to the benchmark problem of a two-dimensional bubble rising in a liquid column presented in [1], and propose two breakup and coalescence problems to assess the ability of a multi-fluid code to model topology changes.
Abstract
In this work we extend the Particle Finite Element Method (PFEM) to multi-fluid flow problems with the aim of exploiting the fact that Lagrangian methods are specially well [...]
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Advances in the particle finite element method (PFEM) for solving coupled problems in engineering
E. Oñate, S. Idelsohn, M. Celigueta, R. Rossi, J. Marti, J. Carbonell, P. Ryzhakov, B. Suárez

(2010). Research Report, Nº PI347

Abstract
We present some developments in the formulation of the Particle Finite Element Method (PFEM) for analysis of complex coupled problems on fluid and solid mechanics in engineering accounting for fluid-structure interaction and coupled thermal effects, material degradation and surface wear. The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in both the fluid and the structure domains. Nodes are viewed as material points which can freely move and even separate from the main analysis domain representing, for instance, the effect of water drops. A mesh connects the nodes defining the discretized domain where the governing equations are solved, as in the standard FEM. The necessary stabilization for dealing with the incompressibility of the fluid is introduced via the finite calculus (FIC) method. An incremental iterative scheme for the solution of the non linear transient coupled fluid-structure problem is described. The procedure for modelling frictional contact conditions at fluid-solid and solid-solid interfaces via mesh generation are described. A simple algorithm to treat soil erosion in fluid beds is presented. An straight forward extension of the PFEM to model excavation processes and wear of rock cutting tools is described. Examples of application of the PFEM to solve a wide number of coupled problems in engineering such as the effect of large waves on breakwaters and bridges, the large motions of floating and submerged bodies, bed erosion in open channel flows, the wear of rock cutting tools during excavation and tunneling and the melting, dripping and burning of polymers in fire situations are presented.
Abstract
We present some developments in the formulation of the Particle Finite Element Method (PFEM) for analysis of complex coupled problems on fluid and solid mechanics in engineering [...]
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Two-noded beam element for composite and sandwich beams using Timoshenko theory and refined zigzag kinematics
E. Oñate, A. Eijo, S. Oller

(2010). Research Report, Nº PI346

Abstract
The so-called zigzag theory has been developed in recent years as an extension of the classical layer-wise theory for modeling composite laminated beams, plates and shells. An advantage of the zigzag theory is that the number of kinematic variables is independent of the number of layers. In this work we present a simple linear two-noded beam element adequate for the analysis of composite and sandwich beams based on the combination of classical Timoshenko beam theory and the refined zigzag kinematics recently proposed by Tessler et al. [19]. The accuracy of the new beam element is tested in a number of examples of applications for composite laminated beams.
Abstract
The so-called zigzag theory has been developed in recent years as an extension of the classical layer-wise theory for modeling composite laminated beams, plates and shells. [...]
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Análisis numérico de los fenómenos hidrodinámicos en escolleras con aplicaciones a presas de materiales sueltos
R. Hernández, A. Larese, E. Oñate

(2010). Research Report, Nº PI348

Abstract
Actualmente las presas de materiales sueltos son la tipología cuya elección es más frecuente debido, en parte, a los grandes avances que se han hecho en el estudio de los materiales que se utilizan en este tipo de estructuras, a la gran facilidad de encontrarlos y a su bajo coste y, por otra parte, a su adaptabilidad a una amplia variedad de emplazamientos. Sin embargo, hay que tener en cuenta su gran vulnerabilidad frente a fenómenos de sobrevertido, que pueden comprometer seriamente la estructura e incluso causar su colapso. Es por todo esto que en los últimos años se está manifestando un interés creciente en el estudio del comportamiento de las presas de material sueltos frente a fenómenos extremos. Esta tesina se enmarca en el contexto del proyecto XPRES del Plan Nacional I+D del Ministerio de Educación y Ciencia [2], cuyo principal objetivo es desarrollar un método computacional para el análisis de la evolución de la filtración, así como el seguimiento del proceso de rotura en las presas de escollera en caso de sobrevertido. Este objetivo requiere el desarrollo de dos modelos numéricos acoplables, uno que modelice el proceso de filtración en el cuerpo de la presa y otro que modelice la respuesta estructural. Se pretende abordar la validación de los algoritmos desarrollados por CIMNE para la modelización de la filtración y determinar cuál de ellos presenta las mejores características para su aplicación en casos reales. La validación se llevará a cabo utilizando Kratos, un código abierto C++ que se está desarrollando en CIMNE pensado para resolver problemas de multifísica mediante el método de los elementos finitos. Los resultados numéricos se compararán los datos experimentales proporcionados por CEDEX y UPM y los modelos teóricos obtenidos por UPM. Esta validación se centrará, principalmente, en el modelo en dos dimensiones, aunque se hará extensible al caso en tres dimensiones.
Abstract
Actualmente las presas de materiales sueltos son la tipología cuya elección es más frecuente debido, en parte, a los grandes avances que se han hecho [...]
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Optimizing rock cutting through computer simulation
J. Rojek, E. Oñate, C. Labra, H. Kargl, J. Akerman

(2010). Technology Innovation in Underground Construction (TUNCONSTRUCT), G. Beer (Ed.)

Abstract
This paper presents an original thermomechanical model of rock cutting with evaluation of tool wear. The model has been developed within the framework of the discrete element method, which is a suitable numerical method to study problems of multiple material fractures likes those of rock cutting. The paper presents brief overview of the theoretical formulation, calibration of the discrete element model, and a number of numerical results obtained in simulation of rock cutting processes typical for underground excavation, using both roadheaders and TBMs.
Abstract
This paper presents an original thermomechanical model of rock cutting with evaluation of tool wear. The model has been developed within the framework of the discrete element [...]
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A multi-method approach towards understanding the pathophysiology of aortic dissections – the complementary role of in-silico, in-vitro and in-vivo information
P. Rudenick, M. Bordone, B. Bijnens, E. Soudah, E. Oñate, D. García-Dorado, A. Evangelista

(2010). Lecture Notes in Computer Science, Camara, O; Pop, M; Rhode, K; et al. (Eds.), Book Series: Lecture Notes in Computer Science, Vol. 6364, pp. 114-123

Abstract
Management and follow-up of chronic aortic dissections continues to be a clinical challenge due to progressive aortic dilatation. To predict dilatation, guidelines suggest follow-up of the aortic diameter. However, dilatation is triggered by haemodynamic parameters (pressure and wall shear stresses (WSS)), and geometry of false (FL) and true lumen (TL). We aimed at a better understanding of TL and FL haemodynamics by performing in-silico (CFD) and in-vitro studies on an idealized dissected aorta and compared this to a typical patient. We observed an increase in diastolic pressure and wall stress in the FL and the presence of diastolic retrograde flow. The inflow jet increased WSS at the proximal FL while a large variability in WSS was induced distally, all being risk factors for wall weakening. In-silico, in-vitro and in-vivo findings were very similar and complementary, showing that their combination can help in a more integrated and extensive assessment of aortic dissections, improving understanding of the haemodynamic conditions and related clinical evolution.
Abstract
Management and follow-up of chronic aortic dissections continues to be a clinical challenge due to progressive aortic dilatation. To predict dilatation, guidelines suggest [...]
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Shock control bump design optimization on natural laminar aerofoil
D. Lee, J. Periaux, K. Srinivas, L. González, N. Qin, E. Oñate

(2010). Computational Fluid Dynamics Review 2010, Part 9, 253-259, Edited by M M Hafez (University of California, Davis, USA), K Oshima (University of Tokyo, Japan), & Dochan Kwak (NASA Ames Research Center, USA)

Abstract
The chapter investigates Shock Control Bumps (SCB) on a Natural Laminar Flow (NLF) aerofoil; RAE 5243 for Active Flow Control (AFC). A SCB approach is used to decelerate supersonic flow on the suction/pressure sides of transonic aerofoil that leads delaying shock occurrence or weakening of shock strength. Such an AFC technique reduces significantly the total drag at transonic speeds. This chapter considers the SCB shape design optimisation at two boundary layer transition positions (0 and 45%) using an Euler software coupled with viscous boundary layer effects and robust Evolutionary Algorithms (EAs). The optimisation method is based on a canonical Evolution Strategy (ES) algorithm and incorporates the concepts of hierarchical topology and parallel asynchronous evaluation of candidate solution. Two test cases are considered with numerical experiments; the first test deals with a transition point occurring at the leading edge and the transition point is fixed at 45% of wing chord in the second test. Numerical results are presented and it is demonstrated that an optimal SCB design can be found to significantly reduce transonic wave drag and improves lift on drag (L/D) value when compared to the baseline aerofoil design.
Abstract
The chapter investigates Shock Control Bumps (SCB) on a Natural Laminar Flow (NLF) aerofoil; RAE 5243 for Active Flow Control (AFC). A SCB approach is used to decelerate supersonic [...]
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Modeling of ground excavation with the particle finite-element method
J. Carbonell, E. Oñate, B. Suarez

Journal of Engineering Mechanics (2010). Vol. 136 (4), pp. 455-463

Abstract
An excavation process is a nonlinear dynamic problem that includes geometrical, material, and contact nonlinearities. The simulation of ground excavation has to face contact interaction in a changing geometry composed by several solid domains. The particle finite-element method (PFEM) is based on a Lagrangian description for modeling the motion of a continuum medium. The PFEM is particularly suitable for modeling a fluid motion with free surfaces. The application of the PFEM in ground excavation includes the use of the remeshing process, α-shape concepts for detecting the domain boundary, contact mechanics laws, material constitutive models, and surface wear models. Everything is correctly matched to quantify the excavation and the corresponding damage caused to the ground. The erosion and wear parameters of the soil/rock material govern the evolution of the excavation process. The preliminary results presented in this paper show that the PFEM it is a very suitable tool for the simulation of ground excavation processes.
Abstract
An excavation process is a nonlinear dynamic problem that includes geometrical, material, and contact nonlinearities. The simulation of ground excavation has to face contact [...]
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