Made available in DSpace on 2014-12-17T14:52:48Z (GMT). No. of bitstreams: 1 JaneteMBP_DISSERT.pdf: 1475621 bytes, checksum: 1fbc2d7ccc4198e247c3fcdf44c5a178 (MD5) Previous issue date: 2009-11-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work addresses biodiesel by transesterification from the use of waste frying oil as a possible technological alternative for both reducing greenhouse gas emissions and by presenting themselves as an environmental call to designate a rational use of oil when no longer played in the environment to become renewable energy. It has proposed location of a residual oil and fat treatment plant to produce biodiesel, using models of Location and Routing for the improvement of routes. To achieve the goal, questionnaires were administered in establishments that use oil or vegetable fat in their productive activities in order to quantify the residue, to analyze actions and environmental perception of people who work directly with the residue on the destination you are being given to oil and fat used. It has indicated using of two single setup location, the method of Center of Gravity and the model of Ardalan, a geographical point that minimizes the costs of transporting waste to the treatment plant. Actions have been proposed for the improvement of collection routes this residue using the Routing Method of Scanning, as an illustration. The results demonstrated the lack of knowledge of the people who deal directly with large amounts of waste, on the environmental impacts caused by their incorrect disposal. The models used were uniform since point out to neighborhoods in similar regions. The neighborhoods of Lagoa Nova / Morro Branco (Ardalan) and Nova Descoberta (Center of Gravity) as ideal for the installation of treatment plant. However, it is suggested to be tested other models that take into account new variables than those used (supply of waste and the distance between points). The routing through the method of scanning has shown that it is possible, in a simple way to optimize routes in order to reduce distances and therefore the logistics costs in the collection of such waste. Introducing a route as a test to gather the twenty largest oil suppliers used in sample frying, using as a main factor time 8 hour of working shift every day / O trabalho aponta o biodiesel por transesterifica??o a partir do aproveitamento de ?leos residuais de fritura como uma das poss?veis alternativas tecnol?gicas tanto para redu??o das emiss?es de gases, quanto por apresentar-se como um apelo ambiental ao designar um uso racional deste ?leo quando deixado de ser jogado no meio ambiente para tornar-se energia renov?vel. Prop?e a localiza??o de uma unidade de tratamento de ?leo e gordura residual para produ??o de biodiesel, usando modelos de Localiza??o e Roteiriza??o para aperfei?oamento das rotas. Para alcan?ar o objetivo foram aplicados question?rios em estabelecimentos que utilizam o ?leo e/ou a gordura vegetal em suas atividades produtivas, no intuito de quantificar o res?duo; analisar as a??es e a percep??o ambiental das pessoas que trabalham diretamente com o res?duo sobre o destino que est? sendo dado ao ?leo e a gordura usados. Indica atrav?s de duas t?cnicas de instala??o ?nica de localiza??o, o m?todo do Centro de Gravidade e o modelo de Ardalan, um ponto geogr?fico que minimize os custos de transporte do res?duo at? a unidade de tratamento. Prop?e a??es para o aperfei?oamento das rotas de coleta deste res?duo utilizando o M?todo de Roteiriza??o da Varredura, a t?tulo de ilustra??o. Os resultados obtidos nas empresas demonstraram falta de conhecimento das pessoas que lidam diretamente com grandes quantidades do res?duo, sobre os impactos ambientais causados por seu descarte incorreto. Os modelos de localiza??o utilizados apresentaram uniformidade visto que apontaram para bairros em regi?es similares. Os bairros de Lagoa Nova/Morro Branco (Ardalan) e Nova Descoberta (Centro de Gravidade) como ideais para a instala??o da unidade de tratamento. Por?m, sugere-se que sejam testados outros modelos que levem em considera??o novas vari?veis al?m das que foram utilizadas (oferta de res?duo e dist?ncia entre os pontos). A roteiriza??o pelo m?todo da Varredura demonstrou que ? poss?vel, de forma simples, otimizar rotas a fim de reduzir dist?ncias e consequentemente os custos log?sticos na coleta desses res?duos. Apresentando uma rota a t?tulo de ensaio para recolhimento nos vinte maiores ofertantes de ?leo usado em fritura da amostra, utilizando como fator principal o tempo de 8 horas de jornada de trabalho di?rias

Made available in DSpace on 2014-12-17T14:53:06Z (GMT). No. of bitstreams: 1 IsaacFF_DISSERT.pdf: 1166658 bytes, checksum: 2cf318ebd7fdf1f86eeab55fd1fe0aa0 (MD5) Previous issue date: 2010-12-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The objective in the facility location problem with limited distances is to minimize the sum of distance functions from the facility to the customers, but with a limit on each distance, after which the corresponding function becomes constant. The problem has applications in situations where the service provided by the facility is insensitive after a given threshold distance (eg. fire station location). In this work, we propose a global optimization algorithm for the case in which there are lower and upper limits on the numbers of customers that can be served / O objetivo no problema de localiza??o de uma facilidade com dist?ncias limitadas ? minimizar a soma das dist?ncias da facilidade para seus clientes, por?m com um limite em cada uma das dist?ncias onde, ap?s esse limite, o impacto na fun??o objetivo torna-se constante. O problema tem aplica??es em situa??es onde o servi?o fornecido pela facilidade ? indiferente depois de um limiar maximo (ex. localiza??o de um corpo de bombeiros). Nesta disserta??o, s?o propostos algoritmos de otimiza??o global para o caso em que existem limites inferior e superior no numero de clientes atendidos

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Neste trabalho, estudamos o problema de localizaÃÃo simples (SPLP - Simple Plant Location Problem). Usando a formulaÃÃo matemÃtica clÃssica e uma outra formulaÃÃo proposta recentemente, desenvolvemos vÃrios algoritmos para encontrar limites inferiores e superiores, bem como algoritmos tipo branch-and-bound. Com a formulaÃÃo clÃssica, tais limites sÃo obtidos utilizando o mÃtodo de correÃÃo de dados e critÃrios de dominÃncia entre os custos …xos e de transporte. Propomos uma projeÃÃo dessa formulaÃÃo, que se mostrou computacionalmente atrativa. Usando a nova formulaÃÃo propomos e mostramos a corretude de vÃrios procedimentos iterativos que procuram encontrar uma soluÃÃo para o problema, resolvendo uma seqÃÃncia de subproblemas paramÃtricos obtidos com a remoÃÃo de variÃveis e restriÃÃes da formulaÃÃo original. Em cada iteraÃÃo desse processo, podemos gerar limites inferiores e superiores. Aplicamos ainda relaxaÃÃo lagrangeana a essa nova formulaÃÃo para obter outros limites. Analisamos vÃrias possibilidades de relaxaÃÃo das restriÃÃes. Desenvolmento tambÃm algoritmos branch-and-bound baseados em ambas as formulaÃÃes e nos limites obtidos. Avaliamos a e…ciÃncia computacional de todos os algoritmos com instÃncias de teste difÃceis, disponÃveis na literatura. Resultados computacionais e comparaÃÃes com outros algoritmos da literatura sÃo reportados. / In this work, we study the Simple Plant Location Problem (SPLP). Using its classical mathematical programming formulation and another recently proposed formulation, we develop several algorithms to …nd lower and upper bounds for the problem as well as branch-and-bound algorithms. With the classical formulation, such bounds are obtained via the data correction method and dominance criteria between …xed and transportation costs. We propose a projection of this formulation that has shown to be computationally atractive. Using the new formulation, we propose and prove the correctness of several iterative procedures that attempt to …nd an optimal solution to the problem by solving a sequence of parametric sub-problems, each one obtained by removing some variables and constraints of the original formulation. At each iteration of this process, we can obtain lower and upper bounds. We also apply Lagrangean relaxation to this new formulation in order to get other bounds. We consider several possibilities of relaxing the constraints. In addition, we develop branch-and-bound algorithms based on both formulations and the obtained bounds. We evaluate the computational e ciency of all proposed algorithms with hard test instances from the literature. Computational results are reported and comparisons with other algorithms from the literature are carried out.

Este trabalho teve como objetivo avaliar a influência do ambiente competitivo na solução de problemas de localização de instalações e desenho da cadeia desenvolvendo um modelo matemático que captasse simultaneamente muitos dos aspectos práticos que impactam no funcionamento da cadeia de suprimentos. A seleção destes aspectos foi baseada nos comentários e sugestões que autores desta linha de pesquisa propuseram para aprofundamento da literatura da área. Foi desenvolvido um modelo de programação linear inteira mista (PLIM) aplicando-o em um problema exemplo para avaliar a hipótese de que a configuração de menor custo da cadeia não necessariamente proporciona maior acessibilidade ao mercado e, em seguida, o mesmo modelo foi aplicado a um problema real, de maior porte, no setor de fertilizantes. / The goal of this study was to evaluate the influence of a competitive environment in solving facility location and network design problems by developing a mathematical model that could capture several of the practical aspects that influence both decisions and operations of the supply chain. The selection of these aspects was based on the comments and suggestions proposed by several authors of this field of the literature. The mathematical program developed is based on mixed integer linear programming (MILP) and is firstly applied on an example problem to evaluate the hypothesis that the chain configuration that provides the lowest cost not necessarily also provides the greatest accessibility to the market. Afterwards, the same optimization model is applied to a larger real problem in the fertilizer industry.

This thesis proposes a planning framework for Autonomous Electric Vehicle (AEV) charging. The framework is intended to help transportation decision-makers determine Electric Vehicle (EV) charging facility locations and capacities for the mixed fleet of Autonomous Vehicle (AV) and Human-driven Vehicle (HDV). The bi-level nature of the framework captures the decision-making processes of the transportation agency decision-makers and travelers, thereby providing solid theoretical and practical foundations for the EV charging network design. At the upper level, the decision-makers seek to determine the locations and operating capacities of the EV charging facilities, in a manner that minimizes total travel time and construction costs subject to budgetary limitations. In addition, the transportation decision-makers provide AV-exclusive lanes to encourage AV users to reduce travel time, particularly at wireless-charging lanes, as well as other reasons, including safety. At the lower level, the travelers seek to minimize their travel time by selecting their preferred vehicle type (AV vs. HDV) and route. In measuring the users delay costs, the thesis considered network user equilibrium because the framework is designed for urban networks where travelers route choice affects their travel time. The bi-level model is solved using the Non-Dominated Sorting Genetic Algorithm (NSGA-II) algorithm.

Hästens Beds is a Swedish luxury bed manufacturer, located in Köping, Sweden. They have a strong global presence, with Europe being the most mature and proven market. European retailers, called Hästens Partners, are serviced from the central warehouse in Borås which also handles all non-European export to Hästens’ other warehouse facilities in Hong Kong and the United States. As a part of Hästens’ planned growth journey, they are interested in reevaluating their European distribution network from a total cost and delivery service perspective. Hence, the purpose of this master’s thesis is to evaluate alternate distribution network designs in Europe for Hästens to reduce total logistics costs without impairing the delivery service level.  Extensive literature studies and initial interviews were conducted to understand both the theoretical field and the Hästens’ case-specific context. Based on this, three main research questions and a corresponding method resulted in a three-step approach to answer the purpose of the study.  In order to generate network structures and then analyze them, it was first necessary to determine the factors that should be included. Cost functions were created based on curve fitting, based on identified cost drivers for the included cost parameters of warehousing, transportation, and inventory carrying. Furthermore, the customer order lead time was concluded to be very generous. This had the consequence of the distribution lead time not putting any constraints on the network design. Lastly, access to transportation infrastructure, especially a port for handling the non-European export, and the general cost disparity between neighboring regions were concluded to be other important factors for the specific case of Hästens.  Center of gravity analyses based on the identified cost driver for outbound costs, m3-km, were then used to generate 13 candidate warehouse locations. In some cases, these locations were altered to better align with the identified important factors of good access to transportation infrastructure and cost disparity. The most strategically viable combinations of the number and echelons of warehouses could be limited to three combinations, all consisting of a single echelon with one, two, or three warehouses respectively. Therefore, three network optimization scenarios were created, minimizing the total cost of inbound and outbound transportation, which led to the generated network alternatives.  Finally, the total logistics costs were calculated and analyzed for the three alternative structures and a model replica of the current structure by utilizing the cost functions for each included cost parameter. The alternatives were also discussed based on delivery service theory and quantified with regard to distances to Partners. After applying sensitivity analysis and discussing the results’ implications for Hästens, Alternative 2* was formed with warehouses in Borås and Rotterdam. All the alternatives’ total logistics costs and average distances to Partners are quantified below.  [TABLE] As can be seen, the cost savings from Alternative 1 compared with the current network are marginal, and the costs of Alternative 2 and 2* are highly similar. Further, preliminary analysis showed that Alternative 2* would not be economically profitable until at least a 500% increase in European outbound transportation volumes. The conclusion that could be drawn from this was that Hästens is not yet suited to scale up its European distribution network to operate more than one warehouse. However, when future sales volumes allow for it, a European distribution center in Rotterdam could be profitable and provide European customers with greater delivery service.

No description available.

Governments in many counties are taking measures to promote electric vehicles. An important strategy is to build enough charging infrastructures so as to alleviate drivers’ range anxieties. To help the governments make plans about the public charging network, we propose a multi-stage stochastic integer programming model to determine the locations and capacities of charging facilities over finite planning horizons. We use the logit choice model to estimate drivers’ random choices towards different charging stations nearby. The objective of the model is to minimize the expected total cost of installing and operating the charging facilities. Two simple algorithms are designed to solve this model, an approximation algorithm and a heuristic algorithm. A branch-and-price algorithm is also designed for this model, and some implementation details and improvement methods are explained. We do some numerical experiments to test the efficiency of these algorithms. Each algorithm has advantages over the CPLEX MIP solver in terms of solution time or solution quality. A case study of Oakville is presented to demonstrate the process of designing an electric vehicle public charging network using this model in Canada. / Thesis / Master of Science (MSc)

Thèse réalisée en cotutelle avec l'Université d'Avignon. / Les problèmes d’optimisation discrète sont pour beaucoup difficiles à résoudre, de par leur nature combinatoire. Citons par exemple les problèmes de programmation linéaire en nombres entiers. Une approche couramment employée pour les résoudre exactement est l’approche de Séparation et Évaluation Progressive. Une approche différente appelée « Resolution Search » a été proposée par Chvátal en 1997 pour résoudre exactement des problèmes d’optimisation à variables 0-1, mais elle reste mal connue et n’a été que peu appliquée depuis. Cette thèse tente de remédier à cela, avec un succès partiel. Une première contribution consiste en la généralisation de Resolution Search à tout problème d’optimisation discrète, tout en introduisant de nouveaux concepts et définitions. Ensuite, afin de confirmer l’intérêt de cette approche, nous avons essayé de l’appliquer en pratique pour résoudre efficacement des problèmes bien connus. Bien que notre recherche n’ait pas abouti sur ce point, elle nous a amené à de nouvelles méthodes pour résoudre exactement les problèmes d’affectation généralisée et de localisation simple. Après avoir présenté ces méthodes, la thèse conclut avec un bilan et des perspectives sur l’application pratique de Resolution Search. / The combinatorial nature of discrete optimization problems often makes them diffi- cult to solve. Consider for instance integer linear programming problems, which are commonly solved using a Branch-and-Bound approach. An alternative approach, Resolution Search, was proposed by Chvátal in 1997 for solving 0-1 optimization problems, but remains little known to this day and as such has seen few practical applications. This thesis attempts to remedy this state of affairs, with partial success. Its first contribution consists in the generalization of Resolution Search to any discrete optimization problem, while introducing new definitions and concepts. Next, we tried to validate this approach by attempting to solve well-known problems efficiently with it. Although our research did not succeed in this respect, it lead us to new methods for solving the generalized assignment and uncapacitated facility location problems. After presenting these methods, this thesis concludes with a summary of our attempts at practical application of Resolution Search, along with further perspectives on this matter.

Master of Science / Department of Industrial & Manufacturing Systems Engineering / Jessica L. Heier Stamm / In many humanitarian and public health settings, multiple organizations act independently to locate facilities to serve an affected population. As a result of this decentralized decision-making environment, individuals’ access to facility resources may suffer in comparison to a hypothetical system in which a single planner locates the facilities to optimize access for all. Furthermore, due to the unanticipated nature of humanitarian events and the urgency of the need, responders often must cope with a high level of uncertainty regarding the future supply of resources and demand for relief. The contributions of this thesis address the challenges that arise due to the decentralized and dynamic nature of humanitarian response. The first goal of this research is to quantify the difference between decentralized system performance and that possible with a centralized planner. The second goal is to demonstrate the value and feasibility of using a dynamic, rolling-horizon framework to optimize facility location decisions over time. This work compares individuals’ access to health facilities resulting from location decisions made by decentralized decision-makers to the access achieved by a centralized model that optimizes access for all. Access is measured using a special case of the gravity model, the Enhanced Two-Step Floating Catchment Area (E2SFCA) method, which is a distance-weighted ratio of capacity to demand. The E2SFCA method is integrated with integer programming to optimize public access to health facilities. This method is applied to the location of cholera treatment facilities in Haiti, which has been afflicted with a cholera epidemic since October 2010. This research finds that access varied significantly across Haiti, and in the month of February 2011, thirty-seven of the 570 sections, representing 474,286 persons (4.8 percent of the population), did not have adequate access to cholera treatment facilities. Using centralized models to optimize accessibility, performance can be improved but no single model is dominant. This paper recommends use of an efficiency-oriented model in conjunction with an equity constraint to make facility location decisions in future responses. Finally, this work successfully integrates measures of access and equity into a rolling-horizon facility location model and demonstrates that these measures can be incorporated in a full-scale implementation to provide dynamic decision support to planners. This paper advocates for greater awareness of the impact of decentralization in humanitarian response and recommends that future work be undertaken to discover incentives and strategies to mitigate the impact of decentralization in future responses.