Cette thèse s’intéresse à trouver des solutions informatiques à certains problèmes de l’optimisation combinatoire, à savoir les problèmes de tournées de véhicules. Elle aborde les problèmes de Transport A la Demande (TAD). L’objectif principal visé dans cette thèse fait appel à certaines approches exactes et certaines approches méta-heuristiques pour résoudre des problèmes d’optimisation multi-objective de Transport A la Demande avec plusieurs véhicules. En effet, nos principaux objectifs de recherche consistent à : -I) Résoudre un problème multi-objectif de Transport A La Demande multi-véhicules basé sur la qualité de service ; - II) Résoudre un autre problème de Transport A la Demande multi-objectifs multi-véhicules. Ce problème traite un cas spécifique et qui consiste à l’application de ce problème aux domaines de l’Hospitalisation A Domicile (HAD). Nous avons appliqué des algorithmes exacts de "Branch and Bound" et des méthodes méta-heuristiques telles que l’algorithme évolutionnaire "Algorithme Génétique" et l’algorithme de "Colonie de Fourmis" pour apporter des solutions efficaces à ces différents problèmes. Un ensemble de résultats numériques est présenté pour chacune de ces méthodes pour montrer leurs capacités de produire des solutions de haute qualité en temps de calcul raisonnables. / This thesis focuses on finding computer science solutions for some combinatorial optimization problems, namely Vehicle Routing Problems (VRP). The thesis addresses the Dial A Ride Problems (DARP). Its main objective is to use some exact and meta-heuristics approaches to solve multi-objective optimization of Dial A Ride Problem with multi-vehicles. Hence, our main research aims are : - I)Solve a multi-objective Dial A Ride Problem with multi-vehicles based on quality of service, this problem treats a general case ; - II) Solve another multi-objective Dial A Ride Problem with multi-vehicles, this problem deals with a specific case which is an application of the Dial A Ride Problem in Home Health Care (HHC). We have also applied exact algorithms "Branch and Bound" and meta-heuristic algorithms such as evolutionary algorithms "Genetic Algorithm" and "Ant Colony" algorithm to provide effective solutions to these different problems. A set of numerical results are presented for each of these methods. Our results show that they produce high quality solutions in a reasonable execution time for all the treated problems.

Este trabalho apresenta um estudo teórico da Técnica de Geração de Colunas (GC) aplicada em alguns Problemas de Roteamento de Veículo (PRV). Essa técnica foi inicialmente utilizada para tratar problemas de otimização de grande porte com estruturas especiais[Dantzig & Wolfe, 1960]. Dentre as diversas classes de problemas de roteamento; revisamos a aplicação dessa técnica a dois casos particulares: O problema de roteamento de helicópteros em plataformas marítimas, cujo objetivo minimizar o custo total do transporte; O problema de roteamento com janela de tempo, onde a função objetivo é descrita pelo tamanho da frota e o custo do percurso. Revisamos e implementamos um algoritmo de caminho mínimo com janela de tempo (CMJT). Esse algoritmo surge como um sub-problema do algoritmo Primai Simplex para resolver o problema de partição de conjunto, utilizado para modelar o problema de roteamento com janela de tempo. / This work presents a study about the Column Generation Technique (CG) applied to some Vehicle Ftouting Problems. The technique was first used to deal with optimization problems having special structures. Among the vaa-ious classes of routing problems, we review the use of the technique in two specific cases: Ftouting helicopters for crew exchanges on off-shore locations, where the objective is to minimize the total transportation cost; Ftouting with time windows, where the objective function is composed by the size of the fleet and the cost of route. We review and implement a shortest path algorithm with time windows. This algorithm aa-ises as a sub-problem in the Primai Simplex algorithm to solve the linear relaxation of the set partitioning problem used to model the routing problem with time windows.

Embora os conceitos logísticos geralmente sejam associados aos processos de manufatura, eles podem ser aplicados a outras áreas, como é o caso do presente trabalho. Os resíduos de serviços de saúde (RSS) compõem uma parcela pequena do total de resíduos sólidos produzidos por um município, mas são particularmente importantes, pois constituem fontes de disseminação de doenças. Desta forma o correto tratamento destes resíduos é importante para a manutenção da saúde e da qualidade de vida da população. Como toda operação de movimentação, o transporte dos RSS gera despesas que os municípios têm que arcar. Racionalizar processos, reduzir custos, aproveitar a sinergia entre os municípios permite que os recursos economizados possam ser gastos com outros benefícios à população. Este trabalho teve como objetivo fazer um estudo logístico, utilizando como ferramenta um Sistema de Informação Geográfica (SIG), e propor alternativas para a resolução do problema do tratamento dos RSS, buscando reduzir o custo de transporte envolvido neste processo. Foi realizado um estudo de caso na Área de Proteção Ambiental Corumbataí, o qual abrangeu doze municípios de pequeno porte. O trabalho considerou quatro alternativas, apresentando nos resultados os pontos positivos e negativos das mesmas. Foi sugerida a formação de um consórcio intermunicipal, como forma de baratear os custos envolvidos no problema abordado. / Although the logistic concepts generally are associates to the manufacture processes, they can be applied in other areas, like in this work. The health care waste constitutes a small parcel of the total of solid residues produced by a city; therefore they are sources of diseases dissemination. The correct treatment of these residues is important for the maintenance of the health and life\'s quality of the population. As all movement\'s operations, the transport of these residues generates expenditures for the cities. Rationalize processes, reduce costs using the synergy advantages between the cities, allow that the saved resources may be expended with others benefits for the population. This work had as objective to make a logistic study, using as tool a Geographic Information System (GIS), and to propose alternatives for the resolution of the treatment\'s problem for the health care waste, searching to reduce transportation\'s costs involved in this process. A case study was developed in Corumbataí Environment Protection Area, which enclosed twelve small cities. The work considered four alternatives, presenting in the results the positive and negative aspects of each one. The formation of a consortium between the cities was suggested, as form to reduce costs in the boarded problem.

La performance logistique des entreprises et l’optimisation des transports sont devenues un grand problème ces dernières années. La planification et l’optimisation des services constituent en particulier un nouveau défi. Afin d’accroître la productivité et de réduire les coûts de la logistique, ce travail de recherche contribue à l’optimisation d’un problème de tournées de service à domicile multi-dépôt, multi-période avec fenêtres de temps de vie réelle. Le problème vient d’un contexte réaliste et est formulé comme un modèle en Mixed Integer Programming (MIP). Les résultats avec Cplex montrent que ce problème ne peut être résolu par des méthodes exactes dans un délai raisonnable pour une utilisation pratique. Par conséquent, nous introduisons des heuristiques. Premièrement, les heuristiques de recherche locales sont utilisées pour résoudre le problème. Les solutions réalisables initiales sont générées par une heuristique de construction et plusieurs heuristiques de recherche locales sont appliquées pour obtenir des solutions dans un temps de calcul assez court. Ensuite, nous proposons un algorithme génétique avec une nouvelle représentation du chromosome et de nouveaux opérateurs génétiques pour le problème abordé. Enfin, nous considérons un algorithme génétique avec contrôle de la diversité pour problèmes à grande échelle. Les solutions infaisables sont prises en compte dans la population et la contribution à la diversité fait partie de l’évaluation afin d’éviter une recherche prématurée. Ces méthodes ont été mises en œuvre avec succès pour optimiser le problème de routage. / The logistics performance of enterprises and the optimization of transportation have become a great issue in recent years. Field force planning and optimization is a new challenge for the service sector. In order to increase productivity and reduce cost of logistics, this research contributes to the optimization of a real-life multi-depot multi-period field service routing problem with time window. The problem is abstracted from the realistic problem and formulated as a Mixed Integer Programming (MIP) model. Computational results with Cplex show that this problem cannot be solved by exact methods in reasonable time for practical use. First, local search heuristics are used for solving the problem. Initial feasible solutions are generated by a constructive heuristic and several local search heuristics are applied to obtain solutions in a very short computing time. Then we propose a genetic algorithm with new representation of chromosome and new genetic operators for the addressed problem. Finally we consider a genetic algorithm with diversity control to deal with large scale problems. Infeasible solutions are taken account in the population and the diversity contribution is part of the evaluation to avoid premature of search. These methods have been successfully implemented to the optimization of the routing problem

Embora os conceitos logísticos geralmente sejam associados aos processos de manufatura, eles podem ser aplicados a outras áreas, como é o caso do presente trabalho. Os resíduos de serviços de saúde (RSS) compõem uma parcela pequena do total de resíduos sólidos produzidos por um município, mas são particularmente importantes, pois constituem fontes de disseminação de doenças. Desta forma o correto tratamento destes resíduos é importante para a manutenção da saúde e da qualidade de vida da população. Como toda operação de movimentação, o transporte dos RSS gera despesas que os municípios têm que arcar. Racionalizar processos, reduzir custos, aproveitar a sinergia entre os municípios permite que os recursos economizados possam ser gastos com outros benefícios à população. Este trabalho teve como objetivo fazer um estudo logístico, utilizando como ferramenta um Sistema de Informação Geográfica (SIG), e propor alternativas para a resolução do problema do tratamento dos RSS, buscando reduzir o custo de transporte envolvido neste processo. Foi realizado um estudo de caso na Área de Proteção Ambiental Corumbataí, o qual abrangeu doze municípios de pequeno porte. O trabalho considerou quatro alternativas, apresentando nos resultados os pontos positivos e negativos das mesmas. Foi sugerida a formação de um consórcio intermunicipal, como forma de baratear os custos envolvidos no problema abordado. / Although the logistic concepts generally are associates to the manufacture processes, they can be applied in other areas, like in this work. The health care waste constitutes a small parcel of the total of solid residues produced by a city; therefore they are sources of diseases dissemination. The correct treatment of these residues is important for the maintenance of the health and life\'s quality of the population. As all movement\'s operations, the transport of these residues generates expenditures for the cities. Rationalize processes, reduce costs using the synergy advantages between the cities, allow that the saved resources may be expended with others benefits for the population. This work had as objective to make a logistic study, using as tool a Geographic Information System (GIS), and to propose alternatives for the resolution of the treatment\'s problem for the health care waste, searching to reduce transportation\'s costs involved in this process. A case study was developed in Corumbataí Environment Protection Area, which enclosed twelve small cities. The work considered four alternatives, presenting in the results the positive and negative aspects of each one. The formation of a consortium between the cities was suggested, as form to reduce costs in the boarded problem.

Les soins de santé à domicile (HHC) sont un large éventail de services de santé pouvant être dispensés à domicile pour une maladie ou une blessure. Ces dernières années, le secteur des soins de santé est devenu l'un des plus grands secteurs de l'économie des pays développés. L'un des défis les plus importants dans le domaine des HHC consiste à affecter plus efficacement les ressources en main-d'œuvre et les équipements sous des ressources limitées. Étant donné que le coût du transport est l’une des dépenses les plus critiques dans les activités de l’entreprise, il est très important d’optimiser le problème de routage des véhicules pour les sociétés HHC.Cependant, la majorité des travaux existants ne prennent en compte que le modèle déterministe. Dans la pratique de HHC, le décideur et les aidants rencontrent souvent des incertitudes. Il est donc essentiel d'intégrer l'incertitude dans le modèle pour établir un calendrier raisonnable pour la société HHC. Cette thèse aborde le problème du routage et de la planification HHC en prenant en compte respectivement la demande non déterministe, le service et le temps de parcours. Le corps principal de la thèse est composé de trois œuvres indépendantes.(1) Sur la base de la théorie de la crédibilité floue, nous avons proposé un modèle de programmation par contraintes de hasard flou (FCCP) pour le problème de routage HHC avec une demande floue. Ce modèle présente à la fois des caractéristiques d'optimisation combinatoire et de FCCP. Pour faire face au problème à grande échelle, nous avons développé un algorithme génétique hybride avec la simulation de Monte Carlo. Trois séries d'expériences ont été menées pour valider les performances du modèle et de l'algorithme proposés. Enfin, l’analyse de sensibilité a également porté sur l’observation du paramètre variable impliqué dans la prise de décision floue.(2) En fonction de l'activité des soignants de HHC, nous avons proposé un modèle de programmation stochastique en deux étapes avec recours (SPR) pour la livraison et la reprise simultanées avec des temps de trajet et de service stochastiques dans HHC. Pour résoudre le modèle, nous avons d’une part réduit le modèle au cas déterministe. Le solveur de Gurobi, le recuit simulé (SA), l’algorithme de chauve-souris, l’algorithme de luciole ont été proposés pour résoudre le modèle déterministe pour 56 instances respectivement. Enfin, le SA a été adopté pour traiter le modèle SPR. Une comparaison entre les solutions obtenues par les deux modèles a également été réalisée pour mettre en évidence la prise en compte des temps de parcours et de service stochastiques.(3) Pour garantir la qualité du service, sur la base d’un budget de la théorie de l’incertitude, nous avons proposé un modèle d’optimisation robuste (RO) pour HHC Routing, prenant en compte les exigences en termes de temps de déplacement et de service. La vérification de la solution réalisable a été réécrite en tant que fonction récursive complexe. Recherche tabou, SA, Recherche de voisinage variable sont également adaptés pour résoudre le modèle. Un grand nombre d'expériences ont été réalisées pour évaluer le modèle déterministe et le modèle RO. Une analyse de sensibilité des paramètres a également été effectuée. / Home health care (HHC) is a wide range of healthcare services that can be given in one's home for an illness or injury. In recent years, the healthcare industry has become one of the largest sectors of the economy in developed countries. One of the most significant challenges in HHC domain is to assign the labor resources and equipment more efficiently under limited resources. Since the transportation cost is one of the most critical spendings in the company activities, it is of great significance to optimize the vehicle routing problem for HHC companies.However, a majority of the existing work only considers the deterministic model. In the practical of HHC, the decision-makers and caregivers often encounter with uncertainties. So, it is essential to incorporate the uncertainty into the model to make a reasonable and robust schedule for HHC company. This thesis addresses the HHC routing and scheduling problem with taking into account the non-deterministic demand, uncertain service and travel time respectively. The main body the thesis is composed of three independent works.(1) Based on the Fuzzy Credibility Theory, we proposed a fuzzy chance constraint programming (FCCP) model for HHC routing problem with fuzzy demand. This model has both characteristics of combinatorial optimization and FCCP. To deal with the large-scale problem, we developed a Hybrid Genetic Algorithm with the Monte Carlo simulation. Three series of experiments were conducted to validate the performance of the proposed model and algorithm. At last the sensitivity analysis was also carried out the observe the variable parameter involved in the fuzzy decision-making.(2) According to the activity of the caregivers in HHC, we proposed a two-stage stochastic programming model with recourse (SPR) for the simultaneous delivery and pick-up with stochastic travel and service times in HHC. To solve the model, firstly, we reduced the model to the deterministic one. Gurobi Solver, Simulated Annealing (SA), Bat Algorithm (BA), Firefly Algorithm (FA) were proposed to solve the deterministic model for 56 instances respectively. At last the SA was adopted to address the SPR model. Comparison between the solutions obtained by the two models was also conducted to highlight the consideration of the stochastic travel and service times.(3) To guarantee the service quality, based on a budget of uncertainty theory, we proposed a Robust Optimization (RO) model for HHC Routing with considering skill requirements under travel and service times uncertainty. The feasible solution check was rewritten as a complex recursive function. Tabu Search, SA, Variable Neighborhood Search are adapted to solve the model. A large number of experiments had been performed to evaluate the deterministic model and the RO model.

[pt] Desde a sua origem, as abordagens a problemas de Otimização Combinatória polarizam-se entre métodos exatos e heurísticos. Recentemente, porém, estratégias que combinam ambos os métodos têm sido propostas para os mais variados problemas, apresentando resultados promissores. Nesse contexto, destacam-se os conceitos de vizinhaças de bola e elipsoidal, que realizam buscas em relação a uma ou mais soluções de referência. Este trabalho estuda a aplicação de tais vizinhanças para o Problema de Roteamento de Veículos com Restrição de Capacidade (CVRP), sobre o algoritmo de Branch-and-Cut-and-Price Robusto. Experimentos foram realizados e seus resultados analisados. / [en] Since its inception, approaches to Combinatorial Optimization were polarized between exact and heuristic methods. Recently, however, strategies that combine both methods have been proposed for various problems, showing promising results. In this context, the concepts of ball and ellipsoidal neighborhood appear, which perform a search regarding one or more reference solutions. This work studies the application of such neighborhoods for the Capacitated Vehicle Routing Problem (CVRP), using the Robust Branchand- Cut-and-Price algorithm. Experiments were made and its results were analyzed.

La distribution de marchandises est un secteur en constant développement et constitue un facteur économique important. Par contre, dans les villes, il contribue notamment aux problèmes de congestion, pollution, bruit et d'autres dérangements à la population des villes. Pour faire face à ces problèmes, une nouvelle discipline est née à la fin du XXe siècle, la " City Logistics ", qui a comme objectifs principaux la réduction de la congestion, la pollution et le bruit occasionné par le transport de marchandises en ville. Dans les dernières années, plusieurs études et expériences se sont développées en toute l'Europe, mais pour l'instant une politique commune en matière de logistique urbaine n'a pas encore été proposée par l'Union Européenne. En Italie, seulement certaines villes de petite taille ont expérimenté des politiques de " city logistics " avec succès, mais sans un lien entre elles. Nous observons que ces expériences utilisent des centres urbains de distribution de marchandises, ce qui peut se traduire en un système de transport à deux ou plus niveaux. Plusieurs études en recherche opérationnelle ont traité des problématiques liées à des systèmes à niveaux multiples pour la distribution de marchandise. Néanmoins, l'optimisation des coûts de transport est en générale réalisé en considérant chaque niveau indépendant des autres, ou en approximant les coûts du transport dans certains niveaux pour simplifier. Un autre problème est le manque d'une unification de la terminologie utilisée dans ces études, qui difficulte la recherche bibliographique. Le but de cette recherche est, d'un coté, proposer des lignes guide d'accion en matière de planification de la distribution urbaine de marchandises, en unifiant certains termes, et d'un autre coté présenter une famille de problèmes d'optimisation de routes des véhicules qui considère les systèmes à niveaux multiples dans son ensemble et pas comme une somme de systèmes indépendants. Dans un premier temps, nous présentons les principales expériences de " city logistics " en Italie, ainsi que des lignes d'action dans la planification des systèmes de distribution urbaine des marchandises qui puissent devenir opérationnels et efficients. Ensuite nous présentons les principales problématiques et limites de l'optimisation de systèmes de transports à niveaux multiples, en unifiant les concepts et la notation. Nous proposons une nouvelle famille de problèmes d'optimisation de routes de véhicules pour des systèmes à niveaux multiples, en détaillant le cas basique : le problème de routes de véhicules à deux niveaux. Nous proposons des modèles mathématiques pour ce problème et des résultats numériques pour illustrer les avantages et les limites de la modélisation de ces systèmes.

This Thesis Work will concentrate on a very interesting problem, the Vehicle Routing Problem (VRP). In this problem, customers or cities have to be visited and packages have to be transported to each of them, starting from a basis point on the map. The goal is to solve the transportation problem, to be able to deliver the packages-on time for the customers,-enough package for each Customer,-using the available resources- and – of course - to be so effective as it is possible.Although this problem seems to be very easy to solve with a small number of cities or customers, it is not. In this problem the algorithm have to face with several constraints, for example opening hours, package delivery times, truck capacities, etc. This makes this problem a so called Multi Constraint Optimization Problem (MCOP). What’s more, this problem is intractable with current amount of computational power which is available for most of us. As the number of customers grow, the calculations to be done grows exponential fast, because all constraints have to be solved for each customers and it should not be forgotten that the goal is to find a solution, what is best enough, before the time for the calculation is up. This problem is introduced in the first chapter: form its basics, the Traveling Salesman Problem, using some theoretical and mathematical background it is shown, why is it so hard to optimize this problem, and although it is so hard, and there is no best algorithm known for huge number of customers, why is it a worth to deal with it. Just think about a huge transportation company with ten thousands of trucks, millions of customers: how much money could be saved if we would know the optimal path for all our packages.Although there is no best algorithm is known for this kind of optimization problems, we are trying to give an acceptable solution for it in the second and third chapter, where two algorithms are described: the Genetic Algorithm and the Simulated Annealing. Both of them are based on obtaining the processes of nature and material science. These algorithms will hardly ever be able to find the best solution for the problem, but they are able to give a very good solution in special cases within acceptable calculation time.In these chapters (2nd and 3rd) the Genetic Algorithm and Simulated Annealing is described in details, from their basis in the “real world” through their terminology and finally the basic implementation of them. The work will put a stress on the limits of these algorithms, their advantages and disadvantages, and also the comparison of them to each other.Finally, after all of these theories are shown, a simulation will be executed on an artificial environment of the VRP, with both Simulated Annealing and Genetic Algorithm. They will both solve the same problem in the same environment and are going to be compared to each other. The environment and the implementation are also described here, so as the test results obtained.Finally the possible improvements of these algorithms are discussed, and the work will try to answer the “big” question, “Which algorithm is better?”, if this question even exists.

Within the wide scope of logistics management,transportation plays a central role and is a crucialactivity in both production and service industry.Among others, it allows for the timely distributionof goods and services between suppliers, productionunits, warehouses, retailers, and final customers.More specifically, Vehicle Routing Problems(VRPs) deal with the design of a set of minimal costroutes that serve the demand for goods orservices of a set of geographically spread customers,satisfying a group of operational constraints.While it was traditionally a static problem, recenttechnological advances provide organizations withthe right tools to manage their vehicle fleet in realtime. Nonetheless, these new technologies alsointroduce more complexity in fleet managementtasks, unveiling the need for decision support systemsdedicated to dynamic vehicle routing. In thiscontext, the contributions of this Ph.D. thesis arethreefold : (i) it presents a comprehensive reviewof the literature on dynamic vehicle routing ; (ii)it introduces flexible optimization frameworks thatcan cope with a wide variety of dynamic vehiclerouting problems ; (iii) it defines a new vehicle routingproblem with numerous applications.