FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Os avanÃos alcanÃados na computaÃÃo mÃvel e na comunicaÃÃo sem o levaram ao desenvolvimento do Sistema Inteligente de Transporte, onde se pode destacar as redes veiculares. Nelas, o roteamento à uma tarefa desaadora devido à alta mobi- lidade dos nÃs, à instabilidade dos enlaces sem-o e a diversidade de cenÃrios. Por essa razÃo, diversos protocolos de roteamento foram projetados com o objetivo de solucionar um ou mais problemas especÃcos de cada cenÃrio. Entretanto, apesar de existirem vÃrias soluÃÃes propostas para o problema do roteamento em redes veicu- lares, nenhuma delas alcanÃou um desempenho satisfatÃrio em mais de um cenÃrio, como urbano e rodovia. Sendo assim, nesta dissertaÃÃo, analisamos atravÃs de si- mulaÃÃes o impacto da densidade, da carga da rede e da mobilidade no desempenho de um protocolo de roteamento para fornecer diretrizes para os projetistas de redes veiculares desenvolverem protocolos de roteamento ecientes, capazes de se adaptar aos cenÃrios urbano e de rodovia. Para alcanÃar esse objetivo, quatro protocolos existentes na literatura foram avaliados nos cenÃrios urbano e de rodovia, dois deles voltados diretamente para redes veiculares e os outro dois tradicionais de redes âd hoâ. / Advances in mobile computing and wireless communications have made possible the development of the Intelligent Transportation System, which contain the vehi- cular networks. There, routing is a challenging task due to the high node mobility, the instability of wireless links and the diversity of scenarios. For this reason, several routing protocols have been designed with the goal of solving one or more specic problems of each scenario. However, although there are several proposed solutions to the routing problem in vehicular networks, none of them has achieved a satisfac- tory performance in more than one scenario, such as urban and highway. Thus, in this work, we rst analyze with simulations the impact of density, the network load and the mobility pattern in the performance of routing protocols for these networks. Then, we provide new directions for designing ecient vehicular network routing protocols, able to adapt to urban and highway scenarios. To achieve this goal, four existing protocols were evaluated in urban and highway scenarios.

Dynamic Traffic Assignment (DTA) is gaining wider acceptance among agencies and practitioners because it serves as a more realistic representation of real-world traffic phenomena than static traffic assignment. Many metropolitan planning organizations and transportation departments are beginning to utilize DTA to predict traffic flows within their networks when conducting traffic analysis or evaluating management measures. To analyze DTA-based optimization applications, it is critical to obtain the dual (or gradient) information as dual information can typically be employed as a search direction in algorithmic design. However, very limited number of approaches can be used to estimate network-wide dual information while maintaining the potential to scale. This dissertation investigates the theoretical/practical aspects of DTA-based dual approximation techniques and explores DTA applications in the context of various transportation models, such as transportation network design, off-line DTA capacity calibration and dynamic congestion pricing. Each of the later entities is formulated as bi-level programs. Transportation Network Design Problem (NDP) aims to determine the optimal network expansion policy under a given budget constraint. NDP is bi-level by nature and can be considered a static case of a Stackelberg game, in which transportation planners (leaders) attempt to optimize the overall transportation system while road users (followers) attempt to achieve their own maximal benefit. The first part of this dissertation attempts to study NDP by combining a decomposition-based algorithmic structure with dual variable approximation techniques derived from linear programming theory. One of the critical elements in considering any real-time traffic management strategy requires assessing network traffic dynamics. Traffic is inherently dynamic, since it features congestion patterns that evolve over time and queues that form and dissipate over a planning horizon. It is therefore imperative to calibrate the DTA model such that it can accurately reproduce field observations and avoid erroneous flow predictions when evaluating traffic management strategies. Satisfactory calibration of the DTA model is an onerous task due to the large number of variables that can be modified and the intensive computational resources required. In this dissertation, the off-line DTA capacity calibration problem is studied in an attempt to devise a systematic approach for effective model calibration. Congestion pricing has increasingly been seen as a powerful tool for both managing congestion and generating revenue for infrastructure maintenance and sustainable development. By carefully levying tolls on roadways, a more efficient and optimal network flow pattern can be generated. Furthermore, congestion pricing acts as an effective travel demand management strategy that reduces peak period vehicle trips by encouraging people to shift to more efficient modes such as transit. Recently, with the increase in the number of highway Build-Operate-Transfer (B-O-T) projects, tolling has been interpreted as an effective way to generate revenue to offset the construction and maintenance costs of infrastructure. To maximize the benefits of congestion pricing, a careful analysis based on dynamic traffic conditions has to be conducted before determining tolls, since sub-optimal tolls can significantly worsen the system performance. Combining a network-wide time-varying toll analysis together with an efficient solution-building approach will be one of the main contributions of this dissertation. The problems mentioned above are typically framed as bi-level programs, which pose considerable challenges in theory and as well as in application. Due to the non-convex solution space and inherent NP-complete complexity, a majority of recent research efforts have focused on tackling bi-level programs using meta-heuristics. These approaches allow for the efficient exploration of complex solution spaces and the identification of potential global optima. Accordingly, this dissertation also attempts to present and compare several meta-heuristics through extensive numerical experiments to determine the most effective and efficient meta-heuristic, as a means of better investigating realistic network scenarios. / text

MATEUS, Bruno Góis. Análise sobre o impacto da densidade veicular, da carga da rede e da mobilidade no desempenho de protocolos de roteamento para redes veiculares. 2010. 137 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Computação, Fortaleza-CE, 2010. / Submitted by guaracy araujo (guaraa3355@gmail.com) on 2016-06-06T19:00:35Z No. of bitstreams: 1 2010_dis_bgmateus.htm: 516 bytes, checksum: 4c8310e1377750fc5ac0860e74c26066 (MD5) / Approved for entry into archive by guaracy araujo (guaraa3355@gmail.com) on 2016-06-06T19:01:05Z (GMT) No. of bitstreams: 1 2010_dis_bgmateus.htm: 516 bytes, checksum: 4c8310e1377750fc5ac0860e74c26066 (MD5) / Made available in DSpace on 2016-06-06T19:01:05Z (GMT). No. of bitstreams: 1 2010_dis_bgmateus.htm: 516 bytes, checksum: 4c8310e1377750fc5ac0860e74c26066 (MD5) Previous issue date: 2010 / Advances in mobile computing and wireless communications have made possible the development of the Intelligent Transportation System, which contain the vehi- cular networks. There, routing is a challenging task due to the high node mobility, the instability of wireless links and the diversity of scenarios. For this reason, several routing protocols have been designed with the goal of solving one or more speci c problems of each scenario. However, although there are several proposed solutions to the routing problem in vehicular networks, none of them has achieved a satisfac- tory performance in more than one scenario, such as urban and highway. Thus, in this work, we rst analyze with simulations the impact of density, the network load and the mobility pattern in the performance of routing protocols for these networks. Then, we provide new directions for designing e cient vehicular network routing protocols, able to adapt to urban and highway scenarios. To achieve this goal, four existing protocols were evaluated in urban and highway scenarios. / Os avanços alcançados na computação móvel e na comunicação sem o levaram ao desenvolvimento do Sistema Inteligente de Transporte, onde se pode destacar as redes veiculares. Nelas, o roteamento é uma tarefa desa adora devido à alta mobi- lidade dos nós, à instabilidade dos enlaces sem- o e a diversidade de cenários. Por essa razão, diversos protocolos de roteamento foram projetados com o objetivo de solucionar um ou mais problemas especí cos de cada cenário. Entretanto, apesar de existirem várias soluções propostas para o problema do roteamento em redes veicu- lares, nenhuma delas alcançou um desempenho satisfatório em mais de um cenário, como urbano e rodovia. Sendo assim, nesta dissertação, analisamos através de si- mulações o impacto da densidade, da carga da rede e da mobilidade no desempenho de um protocolo de roteamento para fornecer diretrizes para os projetistas de redes veiculares desenvolverem protocolos de roteamento e cientes, capazes de se adaptar aos cenários urbano e de rodovia. Para alcançar esse objetivo, quatro protocolos existentes na literatura foram avaliados nos cenários urbano e de rodovia, dois deles voltados diretamente para redes veiculares e os outro dois tradicionais de redes —d ho™.

[pt] Com o advento dos sistemas celulares de segunda e terceira gerações é esperado que as operadoras se vejam obrigadas a enfrentar um aumento dramático na carga de sinalização que trafega sobre a parte fixa da rede móvel. Apesar disso, são raros os provedores de serviços de comunicações móveis que possuem atualmente a capacidade de prever com relativa precisão o montante desse aumento. Este trabalho apresenta as etapas do desenvolvimento de uma ferramenta de simulação para análise de desempenho de redes de comunicação móvel celular com base na carga de sinalização gerada pelos procedimentos que a mantém em operação. A plataforma de simulação inclui um modelo de mobilidade e teletráfego para caracterizar o processo de geração dos cenários típicos de uma rede móvel celular e um modelo de retardos para representação da rede de sinalização. Ao final do estudo,são apresentados exemplos de aplicação da ferramenta na obtenção de resultados sobre gerência de status, gerência de localização, avaliação da carga de sinalização,dimensionamento da rede de sinalização e análise de desempenho para diferentes configurações de rede. / [en] The advent of second and third generation cellular systems make cellular operators face dramatic increase in the signaling traffic over the fixed part of the mobile network. In spite of this, rare mobile communications service providers are able to forecast the above mention increase and quantify it with reasonable precision. This work describes the development process of a simulation tool for performance analysis of cellular mobile network based on the signaling load generated by the procedures that keeps it working. The simulation platform inlcudes a mobility and teletraffic model to describe the generation process of cellular mobile networks tipical scenarios and a delay model to represent the signaling network. At the end, examples showing the application of the simulation tool to obtain results about status and location management, signaling load evaluation, signaling network planning and performance analysis for different network configurations are presented.