published_or_final_version / abstract / toc / Geography and Geology / Doctoral / Doctor of Philosophy

Network design decisions, especially those pertaining to urban infrastructure, are made by a central authority or network leader, and taking into consideration the network users or followers. These network decision problems are formulated as non-linear bi-level programming problems. In this work, a continuous network design problem (CNDP) and discrete network design problem (DNDP) bi-level optimization programs are proposed and solved in the context of transportation planning. The solution strategy involved reformulation and linearization as a single-level program by introducing the optimality conditions of the lower level problem into the upper level problem. For the CNDP, an alternative linearization algorithm (modified least squares partitioning, MLSPA) is proposed. MLSPA takes into consideration the current arc capacity and potential expansion to find a reduced set of planes to generalize the flow-capacity surface behavior. The concepts of flow capacity surface was introduced as a way to model of congested network and capture the effect of capacity on travel time/cost. It was found that the quality of the linear approximation depends on the goodness of fit the bottleneck arcs. The proposed approach was tested with well-known benchmark problems in transportation which yielded promising results in terms of efficiency, without sacrificing solution quality.

abstract: In the U.S., high-speed passenger rail has recently become an active political topic, with multiple corridors currently being considered through federal and state level initiatives. One frequently cited benefit of high-speed rail proposals is that they offer a transition to a more sustainable transportation system with reduced greenhouse gas emissions and fossil energy consumption. This study investigates the feasibility of high-speed rail development as a long-term greenhouse gas emission mitigation strategy while considering major uncertainties in the technological and operational characteristics of intercity travel. First, I develop a general model for evaluating the emissions impact of intercity travel modes. This model incorporates aspects of life-cycle assessment and technological forecasting. The model is then used to compare future scenarios of energy and greenhouse gas emissions associated with the development of high-speed rail and other intercity travel technologies. Three specific rail corridors are evaluated and policy guidelines are developed regarding the emissions impacts of these investments. The results suggest prioritizing high-speed rail investments on short, dense corridors with fewer stops. Likewise, less emphasis should be placed on larger investments that require long construction times due to risks associated with payback of embedded emissions as competing technology improves. / Dissertation/Thesis / M.S. Sustainability 2011

Cette thèse étudie la problématique de la flexibilité dans les chaînes logistiques. La recherche académique a commencé à s’intéresser à cette problématique depuis quelques années, mais les études existantes restent pour la plupart au niveau conceptuel et il y a peu de consensus sur la définition même de la flexibilité. Cette thèse a pour ambition de définir un nouveau cadre pour la flexibilité dans les chaînes logistiques, proposer des mesures quantitatives pour la flexibilité et enfin optimiser l’utilisation de la flexibilité, en particulier dans un contexte de planification intégrée de la production et du transport.Ce travail de thèse vise tout d’abord à établir un nouveau cadre pour la flexibilité de la chaîne logistique, où les différents aspects de la flexibilité sont classifiés en trois catégories principales: flexibilité de la production, flexibilité de la chaîne logistique et flexibilité du système. Dans chacune de ces catégories, on peut trouver des dimensions primordiales et des dimensions moins importantes.Afin d’évaluer la flexibilité de manière quantitative, nous faisons appel à la méthode Analogie Mécanique. Cette méthode propose une analogie entre un système mécanique vibratoire et une chaîne logistique. Dans ce contexte, nous avons développé une étude de cas pour Louis Vuitton afin d’évaluer la flexibilité de leurs magasins, et nous avons établi une procédure pour implémenter cette méthode.Une autre problématique importante est l’utilisation optimale de la flexibilité existante.Nous nous sommes particulièrement intéressés à la planification intégrée de la production et du transport avec des flexibilités sur la capacité de transport, où la production et le transport sont intimement liés du fait du manque de capacité de stockage et doivent être planifiées conjointement. Particulièrement, les véhicules hétérogènes sont pris en compte.Nous avons construit deux modèles de programmation linéaire en nombres mixtes et développé trois algorithmes qui ont été comparées par rapport à la relaxation linéaire pour les instances de grande taille et aux solutions optimales pour des instances de petite taille. Ces comparaisons montrent que les heuristiques proposées sont efficaces pour résoudre des problèmes réels, aussi bien en termes de qualité de solution qu’en termes de temps de calcul. / This thesis focuses on flexibility issues in supply chain. These issues are becoming more and more important for firms because of the increasingly changing business environment and customer behaviors. Although some of these issues have been tackled in academic research in recent years, but studies have mainly concentrated in conceptual levels and there is little consensus even on the definition of flexibility. This thesis aims at defining a new framework for the supply chain flexibility, proposing quantitative measures of the flexibility and optimizing the use of flexibility, especially in an integrated production and transportation planning context. The new framework of supply chain flexibility is based on classification of different flexibility aspects in a supply chain into three main categories - manufacturing flexibility,logistic chain flexibility and system flexibility. These flexibility types are further distinguished into major flexibility dimension and other flexibility dimension.In order to measure supply chain flexibility from a quantitative point of view, Mechanical Analogy method is particularly discussed. A procedure is established to enlarge and carry out this method in supply chain, provided with a case study to evaluate the flexibility of Louis Vuitton stores.One of the most important issues is to optimally make use of the available flexibility. We investigate an Integrated Production and Transportation Planning problem with given flexibility tolerances, where the production and transportation activities are intimately linked to each other and must be scheduled in a synchronized way. Particularly, heterogeneous vehicles are taken into account. Two mixed integer linear programming models are constructed.Three algorithms are developed and compared with linear relaxation bounds for large sized real life instances and with optimal solutions for small sized instances. These comparisons show the effectiveness of our heuristics in solving real life problems

abstract: The development of microsimulation approaches to urban systems modeling has occurred largely in three parallel streams of research, namely, land use, travel demand and traffic assignment. However, there are important dependencies and inter-relationships between the model systems which need to be accounted to accurately and comprehensively model the urban system. Location choices affect household activity-travel behavior, household activity-travel behavior affects network level of service (performance), and network level of service, in turn, affects land use and activity-travel behavior. The development of conceptual designs and operational frameworks that represent such complex inter-relationships in a consistent fashion across behavioral units, geographical entities, and temporal scales has proven to be a formidable challenge. In this research, an integrated microsimulation modeling framework called SimTRAVEL (Simulator of Transport, Routes, Activities, Vehicles, Emissions, and Land) that integrates the component model systems in a behaviorally consistent fashion, is presented. The model system is designed such that the activity-travel behavior model and the dynamic traffic assignment model are able to communicate with one another along continuous time with a view to simulate emergent activity-travel patterns in response to dynamically changing network conditions. The dissertation describes the operational framework, presents the modeling methodologies, and offers an extensive discussion on the advantages that such a framework may provide for analyzing the impacts of severe network disruptions on activity-travel choices. A prototype of the model system is developed and implemented for a portion of the Greater Phoenix metropolitan area in Arizona to demonstrate the capabilities of the model system. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2012

xiii, 307 p. / The midwifery model and the medical model constitute the two main bodies of knowledge and practice that characterize the way pregnancy and birth are viewed in the United States. The midwifery model emphasizes the normalcy of pregnancy and birth, while the medical model is characterized by a belief in the supremacy of technology over nature and in medical supervision and intervention during pregnancy and delivery. Although both models do espouse important information regarding pregnancy and birth and, at times, there is overlap in the practical application of the models, practitioners of the two models rarely interact with one another. The one situation where practitioners of these two models do come into contact is during home-to-hospital transports for planned home births. Through in-depth interviews with direct-entry midwives, mothers, obstetricians, and nurses, this dissertation explores what happens when practitioners of the two models are forced to interact during home-to-hospital transports in order to provide care for women and their babies. Building on Davis-Floyd's and Johnson and Davis-Floyd's work on home-to-hospital transport, interview data suggest that a series of professional and organizational level factors influence the interactions between obstetricians, direct-entry midwives, and nurses during transports. Findings indicate that care providers engage in emotion work as they navigate the disjuncture between home and hospital, managing their own feelings and the feelings of others during a home-to-hospital transport. Due to the lack of institutionalized protocols governing conduct during transports, practitioners of the two models of care are left to construct their own versions of protocols through micro-level interactions, which at particular times and among certain providers have the effect of transcending the boundaries that divide home and hospital. With the interaction that occurs during a home-to-hospital transport as the central focus, this dissertation provides insight into how the lack of integration between the more marginalized midwifery model and the dominant medical model of care in the U.S. affects care providers and laboring/birthing women during transport situations. / Committee in charge: Jocelyn Hollander, Chairperson; Yvonne Braun, Member; Linda Fuller, Member; Carol Stabile, Outside Member; Melissa Cheyney, Non-UO Member

abstract: Institutions of higher education, particularly those with large student enrollments, constitute special generators that contribute in a variety of ways to the travel demand in a region. Despite the importance of university population travel characteristics in understanding and modeling activity-travel patterns and mode choice behavior in a region, such populations remain under-studied. As metropolitan planning organizations continue to improve their regional travel models by incorporating processes and parameters specific to major regional special generators, university population travel characteristics need to be measured and special submodels that capture their behavior need to be developed. The research presented herein begins by documenting the design and administration of a comprehensive university student online travel and mode use survey that was administered at Arizona State University (ASU) in the Greater Phoenix region of Arizona. The dissertation research offers a detailed statistical analysis of student travel behavior for different student market segments. A framework is then presented for incorporating university student travel into a regional travel demand model. The application of the framework to the ASU student population is documented in detail. A comprehensive university student submodel was estimated and calibrated for integration with the full regional travel model system. Finally, student attitudes toward travel are analyzed and used as explanatory factors in multinomial logit models of mode choice. This analysis presents an examination of the extent to which attitudes play a role in explaining mode choice behavior of university students in an urban setting. The research provides evidence that student travel patterns vary substantially from those of the rest of the population, and should therefore be considered separately when forecasting travel demand and formulating transport policy in areas where universities are major contributors to regional travel. / Dissertation/Thesis / Doctoral Dissertation Civil Engineering 2014

abstract: This dissertation research contributes to the advancement of activity-based travel forecasting models along two lines of inquiry. First, the dissertation aims to introduce a continuous-time representation of activity participation in tour-based model systems in practice. Activity-based travel demand forecasting model systems in practice today are largely tour-based model systems that simulate individual daily activity-travel patterns through the prediction of day-level and tour-level activity agendas. These tour level activity-based models adopt a discrete time representation of activities and sequence the activities within tours using rule-based heuristics. An alternate stream of activity-based model systems mostly confined to the research arena are activity scheduling systems that adopt an evolutionary continuous-time approach to model activity participation subject to time-space prism constraints. In this research, a tour characterization framework capable of simulating and sequencing activities in tours along the continuous time dimension is developed and implemented using readily available travel survey data. The proposed framework includes components for modeling the multitude of secondary activities (stops) undertaken as part of the tour, the time allocated to various activities in a tour, and the sequence in which the activities are pursued. Second, the dissertation focuses on the implementation of a vehicle fleet composition model component that can be used not only to simulate the mix of vehicle types owned by households but also to identify the specific vehicle that will be used for a specific tour. Virtually all of the activity-based models in practice only model the choice of mode without due consideration of the type of vehicle used on a tour. In this research effort, a comprehensive vehicle fleet composition model system is developed and implemented. In addition, a primary driver allocation model and a tour-level vehicle type choice model are developed and estimated with a view to advancing the ability to track household vehicle usage through the course of a day within activity-based travel model systems. It is envisioned that these advances will enhance the fidelity of activity-based travel model systems in practice. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2014

O objetivo desta pesquisa é validar a hipótese de que a acessibilidade à oportunidades influencia o comportamento dos padrões de viagens desempenhados pelos indivíduos. Para realizar a verificação desta hipótese foi formulado um procedimento (um teste de hipótese) baseado em um estudo de caso realizado na cidade de Uberlândia, utilizando informações sobre: (i) as características dos deslocamentos dos indivíduos, suas características demográficas e de participação em atividades; (ii) informações sobre o sistema de transportes, e; (iii) informações sobre a distribuição espacial das atividades. Para atingir a finalidade proposta na tese, foram elaborados procedimentos que constituem no processo de verificação da hipótese nula, constituído pelas seguintes etapas: (i) tratamento dos dados; (ii) construção das variáveis (iii) proposta para avaliação da acessibilidade no contexto da formação dos padrões de viagens; (iv) escolha de técnicas de modelagem do comportamento individual referente às decisões sobre padrões de viagens; (v) seleção das técnicas estatísticas para avaliação da significância das variáveis e desempenho dos modelos; (vi) modelagem para simulação do comportamento individual em três níveis de decisão da programação diária de atividades, modo de viagem, destino da atividade primária e padrão de viagens, e; (vii) análise dos resultados obtidos e conclusão sobre a hipótese. Após a realização do experimento realizado com as informações da cidade de Uberlândia, concluiu-se que pela verificação realizada não há elementos para rejeitar a hipótese nula, ou seja, a acessibilidade a oportunidades influencia o comportamento dos padrões de viagens encadeadas desempenhados pelos indivíduos. / The main aim of this work is to submit to a validation test the hypothesis that the accessibility to opportunities influences individuals\' trip chaining behavior. To perform the hypothesis test a procedure was developed on a study case in the city of Uberlandia, using data about: (i) characteristics of the individuals\' trips, their demographic features and activity participation; (ii) transportation system information, and; (iii) information about the spatial distribution of activities. To achieve the purpose of the thesis, it was developed procedures which consist in the hypothesis test, made by the following stages: (i) data processing; (ii) setting of the variables; (iii) a proposal to evaluate the accessibility on the context of trip chaining patterns; (iv) choosing modeling techniques to represent individual behavior regarding to its decisions on trip chaining patterns; (v) selection of statistical techniques for measures of model and variable performance; (vi) modeling individual behavior on three decision levels of the daily activity schedule, mode choice, destination choice and trip chaining patterns, and; (vii) discussion of the results and conclusion about the hypothesis. The main conclusion is that the hypothesis cannot be rejected, i.e., accessibility to opportunities influences individuals\' trip chaining behavior.

Esta dissertação investiga a influência de diversos fatores intervenientes nas emissões veiculares em corredores de ônibus de alta capacidade, conhecidos como BRT Bus Rapid Transit. Esses sistemas têm sido adotados em cidades de todo o mundo devido a possibilidade de atender demandas elevadas a custos relativamente baixos quando comparados com alternativas sobre trilhos, com nível de serviço adequado e possibilitando a redução de emissões. Três categorias de variáveis foram consideradas: (i) variáveis que são função do projeto do corredor de ônibus (infraestrutura, especificações tecnológicas e operacionais); (ii) variáveis que são afetadas pela implantação do corredor (impactos na velocidade média dos outros veículos, utilização de rotas alternativas e transferência modal); (iii) variáveis que dependem de políticas públicas (como mudanças do tipo de combustível ou programas de inspeção veicular). As emissões foram estimadas através de dois procedimentos. Preferencialmente utilizou-se o modelo IVE International Vehicle Emissions, que se baseia no ciclo de condução dos veículos (perfil de variação da velocidade segundo a segundo). Em alguns casos, as estimativas utilizaram resultados de medidas de emissões realizadas pelo IPT Instituto de Pesquisas Tecnológicas, para diferentes tecnologias de ônibus e ciclos de operação padronizados. Os dados necessários para a aplicação do modelo IVE haviam sido coletados anteriormente em São Paulo. Os dados operacionais dos corredores foram obtidos junto a SPTrans e a CET. As análises foram desenvolvidas em três etapas, incluindo progressivamente novas variáveis. Inicialmente foi considerado o efeito de diferentes ciclos de condução sobre as emissões dos ônibus em corredores existentes. Na segunda etapa foi feita uma análise das situações antes e depois da implantação de um corredor (Pirituba-Lapa-Centro), focalizando os impactos sobre as emissões dos ônibus e dos demais veículos, particularmente os autos, e a importância de considerar as emissões dos veículos que passam a percorrer rotas alternativas após a implantação do corredor. Finalmente, foram analisados diferentes cenários para um corredor hipotético, variando tecnologias de ônibus e avaliando os impactos de mudanças na divisão modal, condições de tráfego e outras políticas gerais. Os resultados indicaram a possibilidade de reduções significativas de emissões de poluentes quando utilizados ônibus padrão EURO 3 ou padrão EEV movidos a GNV, bem como evidenciaram a importância de infraestrutura e condições operacionais adequadas para permitir a melhoria dos ciclos de condução dos ônibus. Entretanto, ganhos adicionais são fortemente dependentes de possíveis mudanças que afetem as condições de tráfego dos autos e demais veículos, e de medidas para reduzir emissões, tais como programas de inspeção veicular e de renovação de frota. / The dissertation investigates the influence of several factors affecting vehicular emissions in high-flow bus corridors, also named BRT Bus Rapid Transit. BRT systems are being increasingly adopted in cities around the world due to the possibility to serve high demand levels at relatively low costs when compared to rail options, offering good quality of service and presenting a potential to reduce emissions. Three categories of factors are considered: (i) those directly related to the bus corridor (infrastructure design, technological and operational choices); (ii) those indirectly affected by the implementation of the corridor (such as impacts on average speed of other vehicles, particularly autos, rerouting and the potential for modal change); and (iii) factors related to general policies (such as changes in fuel type or the adoption of vehicle inspection programs). Emissions were estimated using two alternative procedures. The preferred alternative was to use the IVE International Vehicle Emission model, which bases emission estimates on the vehicle driving cycle (the time profile of speed, measured second by second). In other cases, estimates used the results of a series of emissions measurements conducted by IPT Institute of Technological Research of São Paulo for different bus technologies, operating on standard driving cycles. The developers of IVE have collected data about the technological characteristics and driving cycles of the fleet in São Paulo. Data about operations in bus corridors in São Paulo were obtained from SPTrans and CET, the local agencies responsible for bus and traffic operations. The analysis was performed in three stages, progressively extending the variables and factors included. First, the effect on bus emissions of possible changes in driving cycles in four important existing bus corridors in São Paulo was considered. A before and after analysis of a selected bus corridor (Pirituba Lapa Centro) was conducted in the second stage, looking at the impacts on emissions when other vehicles are considered, particularly autos, and highlighting the importance of taking into account vehicles that change to alternative routes after the implementation of the corridor. Finally, different scenarios were analyzed for a hypothetical corridor, varying bus technologies and considering possible impacts of changes in modal choice, traffic conditions, and other general policies. The results indicate the potential for significantly reducing pollutant emissions when Euro 3 bus technologies or enhanced GNV buses are used, as well as the important effect of appropriate infrastructure, operational and traffic engineering measures that allow improved driving cycles for buses. However, overall gains are heavily dependent on possible changes affecting autos and other vehicles, including the impact on traffic conditions and measures to reduce emissions, such as maintenance inspection or fleet renewal programs.