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In this study a dynamic assignment model is developed which estimates travellers' route and departure time choices and the resulting time varying traffic patterns during the morning peak. The distinctive feature of the model is that it does not restrict the geometry of the network to specific forms. The proposed framework of analysis consists of a travel time model, a demand model and a demand adjustment mechanism. Two travel time models are proposed. The first is based on elementary relationships from traffic flow theory and provides the framework for a macroscopic simulation model which calculates the time varying flow patterns and link travel times given the time dependent departure rate distributions; the second is based on queueing theory and models roads as bottlenecks through which traffic flow is either uncongested or fixed at a capacity independent of traffic density. The demand model is based on the utility maximisation decision rule and defines the time dependent departure rates associated with each reasonable route connecting, the O-D pairs of the network, given the total utility associated with each combination of departure time and route. Travellers' choices are assumed to result from the trade-off between travel time and schedule delay and each individual is assumed to first choose a departure time t, and then select a reasonable route, conditional on the choice of t. The demand model has therefore the form of a nested logit. The demand adjustment mechanism is derived from a Markovian model, and describes the day-to-day evolution of the departure rate distributions. Travellers are assumed to modify their trip choice decisions based on the information they acquire from recent trips. The demand adjustment mechanism is used in order to find the equilibrium state of the system, defined as the state at which travellers believe that they cannot increase their utility of travel by unilaterally changing route or departure time. The model outputs exhibit the characteristics of real world traffic patterns observed during the peak, i. e., time varying flow patterns and travel times which result from time varying departure rates from the origins. It is shown that increasing the work start time flexibility results in a spread of the departure rate distributions over a longer period and therefore reduces the level of congestion in the network. Furthermore, it was shown that increasing the total demand using the road network results in higher levels of congestion and that travellers tend to depart earlier in an attempt to compensate for the increase in travel times. Moreover, experiments using the queueing theory based travel time model have shown that increasing the capacity of a bottleneck may cause congestion to develop downstream, which in turn may result in an increase of the average travel time for certain O-D pairs. The dynamic assignment model is also applied to estimate the effects that different road pricing policies may have on trip choices and the level of congestion; the model is used to demonstrate the development of the shifting peak phenomenon. Furthermore, the effect of information availability on the traffic patterns is investigated through a number of experiments using the developed dynamic assignment model and assuming that guided drivers form a class of users characterised by lower variability of preferences with respect to route choice.

Ecotourism as sustainable travel to biodiversity-rich areas advocates the utilisation of modes with minimal impacts to the environment. Yet most often the modes available to the public and the transport network that serves the destination undermine its aims of sustainability. The research looks into the relationship between an ecotourism destination and the transport network that serves it. The objective of the study is to identify policies and structures that contribute to improve its sustainability. (For complete abstract open document)

Transport networks have to provide carriers with time-efficient alternative routes in case of disruptions. It is, therefore, essential for transport network planners and operators to identify sections within the network which, if broken, have a considerable negative impact on the networks performance. Research on transport network analysis provides lots of different approaches and models in order to identify such critical sections. Most of them, however, are only applicable to mono-modal transport networks and calculate indices which represent the criticality of sections by using aggregated data. The model presented, in contrast, focuses on the analysis of intermodal transport networks by using a traffic micro simulation. Based on available, real-life data, our approach models a transport network as well as its actual traffic participants and their individual decisions in case of a disruption. The resulting transport delay time due to a specific disruption helps to identify critical sections and critical networks, as a whole. Therefore, the results are a valuable decision support for transport network planners and operators in order to make the infrastructure less vulnerable, more attractive for carriers and thus more economically sustainable. In order to show the applicability of the model we analyse the Austrian intermodal transport network and show how critical sections can be evaluated by this approach. (authors' abstract)

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / The problems of urban mobility are related, among others, the spatial distribution of activities, the significant growth of automobile use, associated with a poor public transport system, and the occurrence of negative impacts caused by load handling activities in densely populated areas. The population concentration in cities gives urban centers the role of consumption nuclei, which must be supplied continuously from streams of very different nature and origin. To estimate the reliability, risk and vulnerability associated with the route chosen from several points of origin and destination can represent change in decision making. As the cost incurred on a route to greater risk, greater variability in travel time, or more vulnerable to incidents exceed the projected cost of a route optimized by time (based on the shortest path), such a decision can be reviewed. The general objective of this study was to represent the generalized cost, incorporating the concept of vulnerability, reliability and risk of urban road network for decision making regarding the choice of route for cargo transportation. Thus, we developed a method for modeling the generalized cost that incorporates the three attributes in different supply scenarios. The experiment showed the existence of trade-off (conflicting choice)between the average time variables trip, reliability / risk and the generalized cost. Only the information of time and cost of travel are not sufficient to meet the conditions of delivery of merchandise. For the driver, holds the knowledge of the reliability or the risk of delivery of the goods can be a strategic pillar cost reduction or the medium and long-term market gains. / Os problemas de mobilidade urbana estÃo relacionados, dentre outros, à distribuiÃÃo espacial das atividades, ao crescimento expressivo do uso do automÃvel, associado a um sistema deficiente de transporte pÃblico, e à ocorrÃncia de impactos negativos provocados pelas atividades de movimentaÃÃo de cargas nas Ãreas adensadas. A concentraÃÃo populacional nas cidades confere aos centros urbanos papel de nÃcleos de consumo, que devem ser abastecidos continuamente a partir de fluxos de natureza e origem muito diversas. Estimar a confiabilidade, o risco e a vulnerabilidade associados à rota escolhida entre diversos pontos de origem e destino pode representar mudanÃa na tomada de decisÃo. Conforme o custo incorrido em uma rota de maior risco, maior variabilidade no tempo de viagem, ou mais vulnerÃvel à incidentes, supere o custo projetado de uma rota de otimizada pelo tempo (baseada no caminho mÃnimo), tal decisÃo pode ser reavaliada. O objetivo geral do presente trabalho fora representar o custo generalizado, incorporando o conceito da vulnerabilidade, da confiabilidade e do risco de uma rede viÃria urbana para tomada de decisÃo quanto à escolha de rota no transporte de carga. Para isso, desenvolveu-se um mÃtodo para modelagem do custo generalizado que incorpore os trÃs atributos em cenÃrios distintos de abastecimento. O experimento evidenciou a existÃncia de trade-off (escolha conflitante) entre as variÃveis de tempo mÃdio de viagem, confiabilidade/risco e o custo generalizado. Apenas as informaÃÃes de tempo e custo da viagem nÃo sÃo suficientes para suprir as condiÃÃes de entrega da mercadoria. Para o transportador, deter o conhecimento da confiabilidade, ou do risco, da entrega da mercadoria pode ser um pilar estratÃgico de reduÃÃo de custos ou de ganho de mercado à mÃdio e longo prazo.

There is an ongoing evolution of technology towards network convergence and ubiquitous information society in which users have broadband access to information resources and services anywhere, anytime. To realize this vision, a communication infrastructure has to be able to support a core backbone network delivering ultra-high capacity data services, a ubiquitous broadband wireless for last-mile access, and a control/management plane providing intelligent control to the infrastructure. Desirable characteristics of the infrastructure include insertion of future technology, intelligent spectrum management, cost-efficient upgradeability, flexible scalability, and cognitive networking capabilities. Unfortunately, present electronic technology alone is incapable of meeting these requirements.This dissertation describes the initial research into the realization of such an architecture that comprises of three crucial frameworks: 1) photonic-based; 2) dynamic chain processing; 3) and physical layer awareness. Due to the superior signal transport properties of optics, an underlying photonic data layer is able to provide the architecture with much wider bandwidth, greater RF-frequency-scalability, and higher operating RF-frequency. Photonics also enables diverse technologies to be integrated into a seamless communications platform. Dynamic processing chain framework provides the flexibility and future-proof capability via reconfigurability and componentization. Physical-layer-awareness offers support for automated adaptation and intelligent configuration of the data plane in response to the dynamic conditions of the physical layer. Crucial functional blocks in this awareness are: efficient estimation of physical impairments of the components and links; an effective dynamic impairment monitoring mechanism; and proficient adaptation to either maximize or optimize performance.Though the architecture encompasses both optical transport network (OTN) and photonic radio, this dissertation focuses more on the OTN. Central themes of OTN in this dissertation include relating Q-factor with various optical impairments from the perspective of an end-to-end optical path, and extending physical layer awareness with impairment routing. One of the key findings advocates that filtering is a serious limitation to bit-rate independence, protocol independence and network scalability promised by transparent network.

Analysis of differences in price, time and distinct measures of accessibility for eské dráhy Abstract The main aim of this thesis is to resolve the issue of accessibility in the passenger rail network of eské dráhy in the Czech Republic. Secondary objectives are the analysis of distance, time availability, and price of passenger rail service. The main sources are the Railway Timetable 2009 and the geographic database Arc R 500. Basic tool for the processing is geographic information system (GIS) with extension Network Analyst. The main aim of the thesis is to provide a database with the values of distance, time availability and price. Secondary aims are to produce partial maps which present various types of accessibility. Part of the results are also the methodology for establishing different kinds of accessibility, the evaluation of methods used, and quality assessment models used in relation to the database and partial results of comparison with the literature. Keywords: transport accessibility, rail transport, network analysis, accessibility, availability of models, Network Analyst

Nanomaterials are widely investigated by researches and because of their unique properties they have been utilized in many different devices. Nanowires are one of these materials which show deviated mechanical, chemical, physical and optical, properties from their bulk counterparts. These deviations in properties of the nanowires are based on both their high surface to volume ratio and quantum confinement effect. Lately optical properties of nanowires have received great attention as they also exhibit good light sensitivity. Germanium is a semiconductor, which has been used widely as an active material in infrared light detectors. Due to excellent light detection of germanium its nanostructures have also been widely studied in optoelectronic devices. Germanium nanowires have been used in many devices such as field effect transistors, diodes, field emitters and photodetectors. Synthesis of high quality and high aspect ratio germanium nanowires could make important contributions to these devices. There are several synthesis methods for germanium nanowires. These are electrochemical etching, solvothermal, supercritical v fluidic, laser ablation, chemical vapor deposition and vapor transport methods. Among these methods, high quality, single crystalline, defect free germanium nanowires using accessible solid powder precursors could be synthesized with vapor transport method. In the first part of this thesis, germanium nanowire growth with vapor transport method is investigated. One of the most advantageous features of this method is using solid powder precursors instead of toxic gases. Until now, three different kinds of solid germanium precursors have been reported in vapor transport method, all of them are investigated and the resulting nanowires are compared in this thesis. Vapor transport method enables high control over the morphology of the nanowires. The most important parameters which affect the morphology of the nanowires are temperature, pressure and precursor type. Therefore, a detailed parametric study is provided based on these parameters and their effect on the final diameter of the nanowires is determined. The as &ndash / synthesized nanowires contain a very thick oxide layer on their surface. Therefore, oxide removal with acid etching is also investigated in this thesis. In the second part of this thesis, utilization of the germanium nanowire networks in fully transparent, flexible and network enhanced photodetectors is investigated. In order to obtain a germanium nanowire network, the as-synthesized nanowires are transferred from growth substrate to the device substrate by sonication and vacuum filtration. Silver nanowires and single walled carbon nanotubes are used as fully transparent electrodes. Both rigid and flexible photodetectors are fabricated and their current-voltage characteristics and photoresponse behaviors with different germanium nanowire densities are determined.

L'objectif de cette thèse est de fournir une approche globale permettant de déterminer les stratégies de gestion optimales d'un réseau d'ouvrages. La démarche proposée est d'équilibrer les coûts liés à l'offre de l'infrastructure de transport avec les coûts liés à la demande de transport. Le coût de l'offre du réseau d'ouvrage d'art représente le coût des diverses actions de maintenance nécessaires pour obtenir un niveau de service des ouvrages adéquat. Le coût de la demande de transport représente le coût supporté par les usagers du fait de possibles pertes de niveaux de service. La performance des ouvrages est caractérisée à l'aide de deux approches probabilistes, une paramétrique basée sur la théorie de la fiabilité, et une non paramétrique basée sur un indice d'état qui donne une information sur l'état global de l'ouvrage. La méthodologie est proposée dans un premier temps lorsque les deux informations sont accessibles puis lorsque la seule information sur les ouvrages est l'indice d'état. La quantification de la demande de transport est effectuée en affectant le trafic sur le réseau de transport suivant les différentes configurations de l'état des ouvrages, puis en calculant la différence de coût pour chacune de ces configurations par rapport à une situation dite de référence où tous les ouvrages ont un niveau de service idéal. La détermination des stratégies de gestion optimales est effectuée à l'aide d'un algorithme génétique de manière à trouver d'une part les instants optimaux d'intervention et d'autre part les actions de maintenance optimales. Deux procédures sont proposées, une où la somme des coûts des usages et des coûts du gestionnaire est minimisée, une autre où ces deux coûts sont minimisé de manière séparée, un meilleur compromis étant recherché. La méthodologie proposée permet de déterminer les calendriers de maintenance optimaux d'un réseau d'ouvrages d'art pour un horizon donné, de répondre aux questions « quand » et « comment » intervenir, pour disposer d'un fonctionnement du réseau de transport le meilleur possible tout en ajustant les coûts d'intervention / In a context of scarce capital resources and to tackle the ageing of the bridge stock, stakeholders require and use decision making techniques. These tools prioritize at least maintenance actions and optimize allocation of funds eventually. However, all these bridge management systems have an individual strategy approach. They do not include the performance of the transportation network as a criterion in the decision process. The general principle is to find the most appropriate maintenance strategy for each bridge belonging to a network. This approach is not necessarily the best suited strategy for a transportation network. The aim of this thesis is to propose a methodology that provides optimal maintenance strategies for a network of bridges and not for each bridge taken as individuals. The proposed methodology consists in balancing supply costs provided by the infrastructure network with demand costs of the network users. The supply costs are those of all needed maintenance actions, performed by the bridge owner, to provide an adequate level of service for the bridges. The demand costs are those supported by the network users in case of inadequate level of service. The assessment of the supply costs requires to introduce performance of bridges. To take into account the uncertainties in the ageing process of bridges, the performance is calculated by using two probabilistic approaches : a parametrical one that is based on the reliability theory and that applies a failure mode for each bridge, and a non parametrical one that is based on a condition index that gives an information on the overall condition of the bridge. The methodology is proposed in a first time when both information are known, and in a second time when only the condition index is available. Besides, The demand costs are quantified by determining the traffic assignment if there is a traffic disruption for a combination of bridges, then by calculating the difference of user costs for these events with the reference when all bridges are in good condition and ideal performance. Optimal management strategies are determined by using genetical algorithms. First, optimal maintenance times are found for each bridge. Second, optimal maintenance actions are found. Two approaches are proposed. In a first one, the sum of user costs and maintenance costs is minimized. In a second one both user and maintenance costs are minimized separately and the best compromise is determined. Finally, the proposed methodology allows to determine the optimal maintenance actions planning for a given time period. It helps to answer the two questions : « when » and « how » take decisions in order to have the best network system by optimizing the different costs

L’objectif de ce travail consiste en la modélisation des flux de véhicules d’un grand et dense réseau de transport multimodal. Le travail s’organise en deux parties: un aspect théorique et un aspect développement. L’étude théorique met l’accent sur la façon dont un réseau multimodal peut être modélisé et comment sa performance en termes d’offre peut être optimisée. Pour ce faire, trois études principales sont réalisées: la prévision et la régulation des flux de trafic sur les grands réseaux de surface, la multimodalité véhiculaire dans les grands réseaux de surface prenant en compte les nouvelles formes de mobilité, et enfin l’impact de l’information sur le coût des itinéraires. La partie développement consiste en la conception d’un simulateur de flux de trafic pour réguler le trafic multimodal véhiculaire. Le simulateur développé devrait aider les opérateurs de transport et les collectivités territoriales dans leurs stratégies de gestion des flux de trafic / The objective of this work consists on the modeling of traffic flow of a large multimodaltransportation network. The work is organized in two parts: a theoretical study part anda development part. The theoretical study emphasizes on how a multimodal network canbe model and how its performance in terms of supply can be optimized. To do so, threemain studies are discussed: the traffic flow prediction and regulation on large surface net-works, the vehicular multimodality in big surface networks taking into account new forms ofmobility, and finally the impact of the information on the cost of the itineraries. The devel-opment part consists on the conception of a traffic flow simulator to regulate the vehicularmultimodal traffic. The developed simulator should assist transport operators and territorialcommunities in their traffic flow management strategies