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Submitted by Caroline Periotto (carol@ufscar.br) on 2016-09-19T18:29:26Z No. of bitstreams: 1 DissRBL.pdf: 2233937 bytes, checksum: 7a73fb1e4ba8f340cb8d4bdf4e8153d4 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-20T18:01:34Z (GMT) No. of bitstreams: 1 DissRBL.pdf: 2233937 bytes, checksum: 7a73fb1e4ba8f340cb8d4bdf4e8153d4 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-20T18:05:15Z (GMT) No. of bitstreams: 1 DissRBL.pdf: 2233937 bytes, checksum: 7a73fb1e4ba8f340cb8d4bdf4e8153d4 (MD5) / Made available in DSpace on 2016-09-20T18:05:28Z (GMT). No. of bitstreams: 1 DissRBL.pdf: 2233937 bytes, checksum: 7a73fb1e4ba8f340cb8d4bdf4e8153d4 (MD5) Previous issue date: 2015-12-14 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / The Brazilian market for dairy products is highly competitive and is still dominated by multinationals. Thus, it's essential that the national companies to invest in operational efficiency in order to compete successfully. Therefore, this research focuses in a small dairy company of the state of Pará, whose distribution system requires periodic stops for battery recharging. Moreover, the system is characterized by multiple periods and multiple time windows. To our knowledge, so far the literature hasn't presented a directly applicable methodology for the treatmeant of the application with similar characteristics. Therefore, aiming to provide more effective solutions than the ones in practice, a mixed integer linear model was developed to describe (and solve) the problem as a vehicle routing problem with time window constraints, multi-period and periodic stops for recharging. The results showed that the model adequately describes the distribution of the company, and the obtained solutions are better than those currently practiced. Furthermore, the model shows good performance within 3600 seconds of computational time for instances of 40 customers, 1 vehicle and 1 and 2 recharging stations. Aiming to tackle with larger examples, we developed a mathematical programming heuristic Relax-and-Fix to solve the model. It was also tested adapting a similar model present in the literature in order to analyze if the relaxation of some restrictions have a positive impact on the quality of the solutions. Finally, we propose a location-distribution model for recharging stations in order to examine whether the addition of new stations produce significant improvements in the solutions. / O mercado brasileiro de laticínios é altamente competitivo, sendo ainda dominado por multinacionais. Desta forma, é indispensável que as empresas nacionais invistam na eficiência operacional de forma a concorrer satisfatoriamente neste mercado. À vista disso, o foco desta pesquisa é uma pequena empresa de laticínios do Estado do Pará, cujo o sistema de distribuição a pontos de venda possui a particularidade de necessitar de paradas periódicas para recarga da bateria. Ainda, esse sistema tem como característica múltiplos períodos e múltiplas janelas de tempo. Nota-se que o levantamento bibliográfico realizado não apontou nenhuma metodologia diretamente aplicável para solução da aplicação real tratada. Portanto, objetivando provar soluções mais efetivas que as correntemente aplicadas na prática, foi desenvolvido um modelo linear inteiro misto para descrever (e resolver) o problema como um problema de roteamento de veículos com restrições janela de tempo, multi-períodos e paradas periódicas para recarga. Os resultados mostraram que o modelo proposto descreve adequadamente o processo distribuição da empresa, e as soluções obtidas são melhores que as praticadas atualmente. Além disso, verificou-se que o modelo tem um desempenho satisfatório em até 3600 segundos de processamento para instâncias de até 40 clientes, 1 veículo e até 2 postos de recarga. Com vistas ao tratamento de problemas de maior porte, foi desenvolvida uma heurística de programação matemática do tipo Relax-and-Fix para resolução do modelo. Também foi testada a adaptação de um modelo similar presente na literatura, visando analisar se a relaxação de algumas restrições impacta positivamente na qualidade das soluções. Finalmente, é proposto um modelo de localização-distribuição de postos de recarga, de forma a se examinar se a inclusão de novos postos produz melhorias significativas nas soluções atuais. / FAPESP: 14/10330-0

Os consórcios são conhecidos pelo aumento da capacidade de realização que confere aos participantes, e maior eficiência no uso dos recursos disponíveis, o que auxiliaria os pequenos governos locais para solucionar a escassez de recursos. Este trabalho apresenta o estudo do sistema consorciado intermunicipal para destinação dos resíduos sólidos urbanos, para auxiliar os municípios de pequeno porte na solução da inadequada destinação do lixo, responsáveis por constantes impactos ambientais. Os estudos foram realizados através de análises de custos com enfoque logístico, no nível estratégico de localização de facilidades e roteirização e programação da frota. Os estudos foram possíveis, com o auxílio do software TransCAD, uma ferramenta de Sistema de Informações Geográficas. Através do TransCAD, foi realizado a localização dos aterros sanitários, obedecendo-se as restrições impostas, e a roteirização da frota de veículos, que levassem ao menor custo logístico. Para se chegar à situação de menor custo, diversas configurações foram consideradas, nas quais foram variados o número de aterros que atendem os municípios, e a presença ou não de estações de transferência de resíduos. O método desenvolvido promoveu a análise de custos da implantação e operação do sistema consorciado, que consiste desde a coleta de resí-duos, até a disposição final em aterros sanitários. Os resultados deste trabalho comprovaram quantitativamente que o consórcio é mais eficiente do que a solução isolada para cada município. / The consortium are known by the growth of the accomplishment capacity that grants to the participants, and larger efficiency in the use of the available resources, what would aid the small local governments to solve the lack of resources. This work presents the study of the intermunicipal consortium system for the destination of the urban solid waste, to aid the small cities to solve the inadequate destination of the waste, responsible for constant environmental damages. The studies were developed through the costs analysis with logistics focus, on the strategic level of facilities location and the vehicle routing. The studies were possible with the aid of the software TransCAD, a tool of Geographical Information System. Through the TransCAD, being obeyed the imposed restrictions, the location of the sanitary landfill was made, and vehicles routing, to take to the lowest logistics cost. To reach the situation of lowest cost, several configurations were considered, in which the number of sanitary landfill for the cities were varied, and the inclusion or not the solid waste transfer stations. The developed method promoted the cost analysis of the implantation and operation of the consortium system, from the waste collection, until the final disposition in sanitary landfills. The results of this work proved quantitatively that the consortium is more efficient than the isolated solution for each city.

Tesis por compendio / [ES] La gestión sostenible de las cadenas de suministro se ha transformado en un tema de alto interés entre profesionales e investigadores en el ámbito de la ingeniería industrial. El impacto que generan las actividades económicas en el medioambiente y en las comunidades donde éstas se ubican ha generado un incremento en el desarrollo de herramientas que permitan incorporar dichos impactos en las decisiones tomadas en el nivel estratégico de las empresas e industrias. Es así como surgen nuevos paradigmas respecto al modelo de producción, como por ejemplo la economía circular, donde se busca transitar desde una economía de producción lineal, hacia una circular reduciendo al mínimo la generación de desperdicios, ya sea material y/o energético. En este contexto, esta tesis doctoral, sustentada en una revisión de la literatura y en un análisis de modelos de optimización matemática de referencia, propone un marco conceptual como herramienta de soporte para seguir desarrollando modelos cuantitativos para dar soporte a los problemas de localización, inventario y transporte (LIT) en cadenas de suministro sostenibles, así como, un modelo de optimización multiobjetivo no lineal entero mixto (MOMINLP) para diseñar una cadena de suministro sostenible de bucle cerrado considerando las decisiones LIT, donde los aspectos de sostenibilidad: económico, medioambiental y social son incorporados en cada una de las decisiones anteriores. El modelo propuesto, denominado 3S-LIT, considera cuatro funciones objetivo que pretenden: (1) minimizar el coste total de la cadena de suministro; (2) minimizar los costes asociados a la emisión de CO2 equivalente; (3) minimizar el coste social relacionado con los accidentes laborales; y (4) maximizar el impacto social, medido como el incremento en cuanto a la generación de empleos directos e indirectos y la reducción en la cantidad de personas afectas por los riesgos del transporte dentro de la cadena de suministro. El modelo 3S-LIT ha sido validado en una empresa del sector minero del cobre obteniendo un mejor desempeño en los valores de las funciones objetivo respecto a los obtenidos en la situación actual. Además, el modelo 3S-LIT se ha comparado con un enfoque existente en la literatura científica obteniéndose unos resultados satisfactorios tanto en términos de funcionalidades como de resultados. Finalmente, el modelo propuesto de optimización matemática, 3S-LIT, es replicado en un modelo de simulación con el cual se estudiaron posibles escenarios de disrupción de la cadena de suministro con el objetivo de analizar su capacidad resiliente. / [CA] La gestió sostenible de les cadenes de subministrament s'ha transformat en un tema d'alt interès entre professionals i investigadors en l'àmbit de l'enginyeria industrial. L'impacte que generen les activitats econòmiques en el medi ambient i en les comunitats on aquestes se situen ha generat un increment en el desenvolupament d'eines que permeten incorporar aquests impactes en les decisions preses en el nivell estratègic de les empreses i indústries. És així com sorgeixen nous paradigmes respecte al model de producció, com per exemple l'economia circular, on se cerca transitar des d'una economia de producció lineal, cap a una circular reduint al mínim la generació de desaprofitaments, ja siga material i/o energètic. En aquest context, aquesta tesi doctoral, sustentada en una revisió de la literatura i en una anàlisi de models d'optimització matemàtica de referència, proposa un marc conceptual com a eina de suport per a continuar desenvolupant models quantitatius per a donar suport als problemes de localització, inventari i transport (LIT) en cadenes de subministrament sostenibles, així com, un model d'optimització multi-objectiu no lineal enter mixt (MOMINLP) per a dissenyar una cadena de subministrament sostenible de bucle tancat considerant les decisions LIT, on els aspectes de sostenibilitat: econòmic, mediambiental i social són incorporats en cadascuna de les decisions anteriors. El model proposat, denominat 3S-LIT, considera quatre funcions objectiu que pretenen: (1) minimitzar el cost total de la cadena de subministrament; (2) minimitzar els costos associats a l'emissió de CO2 equivalent; (3) minimitzar el cost social relacionat amb els accidents laborals; i (4) maximitzar l'impacte social, mesurat com l'increment quant a la generació d'ocupacions directes i indirectes i la reducció en la quantitat de persones afectes pels riscos del transport dins de la cadena de subministrament. El model 3S-LIT ha sigut validat en una empresa del sector miner del coure obtenint un millor acompliment en els valors de les funcions objectiu respecte als obtinguts en la situació actual. A més, el model 3S-LIT s'ha comparat amb un enfocament existent en la literatura científica obtenint-se uns resultats satisfactoris tant en termes de funcionalitats com de resultats. Finalment, el model proposat d'optimització matemàtica, 3S-LIT, és replicat en un model de simulació amb el qual es van estudiar possibles escenaris de disrupció de la cadena de subministrament amb l'objectiu d'analitzar la seua capacitat resilient. / [EN] Sustainable supply chain management has become a topic of great interest among practitioners and researchers in the field of industrial engineering. The impact generated by economic activities on the environment and the communities where they are located has generated an increase in the development of tools that allow the incorporation of these impacts in the decisions taken at the strategic level of companies and industries. This is how new paradigms emerge regarding the production model, such as the Circular Economy, which seeks to move from a linear production economy to a circular one by minimising the generation of waste, both material and energetic. In this context, this PhD thesis, supported by a state-of-the-art study and the analysis of benchmark mathematical optimisation models, presents a conceptual framework to provide the key elements that act as a valuable tool to further develop quantitative models of location, inventory and transport (LIT) problems in sustainable supply chains, and a novel mixed integer non-linear multi-objective mixed integer multi-objective optimisation model (MOMINLP) for designing a closed-loop sustainable supply chain considering location, inventory and transportation decisions, where economic, environmental and social sustainability aspects are incorporated in each of the above mentioned decisions. The proposed model, called 3S-LIT, considers four objective functions that aim to: (1) minimise the total cost of the supply chain, (2) minimise the costs associated with CO2 equivalent emissions, (3) minimise the social cost related to occupational accidents, and (4) maximise the social impact, measured as a higher generation of direct and indirect jobs and a lower number of people affected by transport risks within the chain. The 3S-LIT model has been applied in a company in the copper mining sector, confirming a better performance in the values of the objective functions compared to those obtained in the current situation. In addition, the mathematical optimisation model is replicated in a simulation model with which possible supply chain disruption scenarios were studied to analyse the resilience of the supply chain. / This thesis has been developed within the Research Centre on Production Management and Engineering (CIGIP) of the Universitat Politècnica de València, within the framework of the projects: "Industrial Production and Logistics Optimization in Industry 4.0" (i4OPT) (Ref. PROMETEO/2021/065) granted by the Valencian Regional Government and received funding from Grant RTI2018-101344-B-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”; “Validation of transferable results of optimisation of zero-defect enabling production technologies for supply chain 4.0” (CADS4.0-II) from the grant PDC2022-133957-I00; and by European Union Next GenerationEU/PRTR, and from the European Union’s Horizon Europe research and innovation programme under grant agreement No. 101070076 "Optimizing Production and Logistic Resources in the Time-critical Bio Production Industries in Europe" (CLARUS). It was also funded by the National Agency for Research and Development (ANID)/Scholarship Program/Doctorado Becas en el Extranjero/2020 – 72210174 and sponsored by the Universidad de Atacama as part of an academic improvement plan. / Becerra Muñoz, PA. (2023). Quantitative Models of Location, Inventory and Transportation Decisions for Sustainable Supply Chain Management [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/196651 / Compendio

Le besoin grandissant pour une planification urbaine plus durable et pour des interventions publiques visant à l'amélioration du bien-être collectif, ont grandement contribué à un engouement pour les espaces verts. Les parcs sont reconnus pour leur impact positif en zone urbaine dense, et nous sommes intéressés par l'application des concepts théoriques du domaine de la recherche opérationnelle pour assister les décideurs publics afin d'améliorer l'accessibilité, la distribution et la conception des parcs. Étant donné le contexte, nous sommes particulièrement motivés par le concept d'équité, et étudions le comportement des usagers des parcs à l'aide d'un modèle d'interaction spatiale, tel qu'appliqué dans les problèmes d'emplacement d'installations dans un marché compétitif. Dans cette recherche, nous présentons un modèle d'emplacement d'installations à deux étapes pouvant être adapté pour assister les décideurs publics à l'échelle de la ville. Nous étudions spécifiquement l'application aux espaces verts urbains, mais soulignons que des extensions du modèle peuvent permettre d'aborder d'autres problèmes d'emplacements d'installations sujets à des enjeux d'équité. La première étape de notre problème d'optimisation a pour but d'évaluer l'allocation la plus équitable du budget de la ville aux arrondissements, basé sur une somme du budget pondérée par des facteurs d'équité. Dans la deuxième étape du modèle, nous cherchons l'emplacement et la conception optimale des parcs, et l'objectif consiste à maximiser la probabilité totale que les individus visitent les parcs. Étant donné la non-linéarité de la fonction objective, nous appliquons une méthode de linéarisation et obtenons un modèle de programmation linéaire mixte en nombres entiers, pouvant être résolu avec des solveurs standards. Nous introduisons aussi une méthode de regroupement pour réduire la taille du problème, et ainsi trouver des solutions quasi optimales dans un délai raisonnable. Le modèle est testé à l'aide de l'étude de cas de la ville de Montréal, Canada, et nous présentons une analyse comparative des résultats afin de justifier la performance de notre modèle. / The recent promotion of sustainable urban planning combined with a growing need for public interventions to improve well-being and health in dense urban areas have led to an increased collective interest for green spaces. Parks have proven a wide range of benefits in urban areas, and we are interested in the application of theoretical concepts from the field of Operations Research to assist decision-makers to improve parks' accessibility, distribution and design. Given the context of public decision-making, we are particularly concerned with the concept of fairness, and are focused on an advanced assessment of users' behavior using a spatial interaction model (SIM) as in competitive facility locations' frameworks. In this research, we present a two-stage fair facility location and design (2SFFLD) model, which serves as a template model to assist public decision-makers at the city-level for the urban green spaces (UGSs) planning. We study the application of the 2SFFLD model to UGSs, but emphasize the potential extension to other applications to location problems concerned with fairness and equity. The first-stage of the optimization problem is about the optimal budget allocation based on a total fair-weighted budget formula. The second-stage seeks the optimal location and design of parks, and the objective consists of maximizing the total expected probability of individuals visiting parks. Given the non-linearity of the objective function, we apply a ``Method-based Linearization'' and obtain a mixed-integer linear program that can be solved with standard solvers. We further introduce a clustering method to reduce the size of the problem and determine a close to optimal solution within reasonable time constraints. The model is tested using the case study of the city of Montreal, Canada, and comparative results are discussed in detail to justify the performance of the model.

La conception de réseaux est un riche sous-domaine de l'optimisation combinatoire ayant de nombreuses applications pratiques. Du point de vue méthodologique, la plupart des problèmes de cette classe sont notoirement difficiles en raison de leur nature combinatoire et de l'interdépendance des décisions qu'ils impliquent. Ce mémoire aborde deux problèmes de conception de réseaux dont les structures respectives posent des défis bien distincts. Tout d'abord, nous examinons un problème déterministe dans lequel un client doit acquérir au prix minimum un certain nombre d'unités d'un produit auprès d'un ensemble de fournisseurs proposant différents coûts fixes et unitaires, et dont les stocks sont limités. Ensuite, nous étudions un problème probabiliste dans lequel une entreprise entrant sur un marché existant cherche, en ouvrant un certain nombre d'installations parmi un ensemble de sites disponibles, à maximiser sa part espérée d'un marché composé de clients maximisant une fonction d'utilité aléatoire. Ces deux problèmes, soit le problème de transport à coût fixe à un puits et le problème d'emplacement d'installations compétitif basé sur les choix, sont étroitement liés au problème du sac à dos et au problème de couverture maximale, respectivement. Nous introduisons de nouvelles reformulations prenant avantage de ces connexions avec des problèmes classiques d'optimisation combinatoire. Dans les deux cas, nous exploitons ces reformulations pour démontrer de nouvelles propriétés théoriques et développer des méthodes de résolution efficaces. Notre nouvel algorithme pour le problème de transport à coûts fixes à un puits domine les meilleurs algorithmes de la littérature, réduisant le temps de résolution des instances de grande taille jusqu'à quatre ordres de grandeur. Une autre contribution notable de ce mémoire est la démonstration que la fonction objectif du problème d'emplacement d'installations compétitif basé sur les choix est sous-modulaire sous n'importe quel modèle de maximisation d’utilité aléatoire. Notre méthode de résolution basée sur la simulation exploite cette propriété et améliore l'état de l'art pour plusieurs groupes d'instances. / Network design is a rich subfield of combinatorial optimization with wide-ranging real-life applications. From a methodological standpoint, most problems in this class are notoriously difficult due to their combinatorial nature and the interdependence of the decisions they involve. This thesis addresses two network design problems whose respective structures pose very distinct challenges. First, we consider a deterministic problem in which a customer must acquire at the minimum price a number of units of a product from a set of vendors offering different fixed and unit costs and whose supply is limited. Second, we study a probabilistic problem in which a firm entering an existing market seeks, by opening a number of facilities from a set of available locations, to maximize its expected share in a market composed of random utility-maximizing customers. These two problems, namely the single-sink fixed-charge-transportation problem and the choice-based competitive facility location problem, are closely related to the knapsack problem and the maximum covering problem, respectively. We introduce novel model reformulations that leverage these connections to classical combinatorial optimization problems. In both cases, we exploit these reformulations to prove new theoretical properties and to develop efficient solution methods. Our novel algorithm for the single-sink fixed-charge-transportation problem dominates the state-of-the-art methods from the literature, reducing the solving time of large instances by up to four orders of magnitude. Another notable contribution of this thesis is the demonstration that the objective function of the choice-based competitive facility location problem is submodular under any random utility maximization model. Our simulation-based method exploits this property and achieves state-of-the-art results for several groups of instances.