This thesis proposes a new simulated annealing approach to solve multiple objective sequencing problems in mixed-model assembly lines. Mixed-model assembly lines are a type of production line where a variety of product models similar in product characteristics are assembled. Such an assembly line is increasingly accepted in industry to cope with the recently observed trend of diversification of customer demands. Sequencing problems are important for an efficient use of mixed-model assembly lines. There is a rich of criteria on which to judge sequences of product models in terms of line utilization. We consider three practically important objectives: the goal of minimizing the variation of the actual production from the desired production, which is minimizing usage variation, workload smoothing in order to reduce the chance of production delays and line stoppages and minimizing total set-ups cost. A considerate line manager would like to take into account all these factors. These are important for an efficient operation of mixed-model assembly lines. They work efficiently and find good solution in a very short time, even when the size of the problem is too large. The multiple objective sequencing problems is described and its mathematical formulation is provided. Simulated annealing algorithms are designed for near or optimal solutions and find an efficiency frontier of all efficient design configurations for the problem. This approach combines the SA methodology with a specific neighborhood search, which in the case of this study is a "swapping two sequence". Two annealing methods are proposed based on this approach, which differ only in cooling and freezing schedules. This research used correlation to describe the degree of relationship between results obtained by method B and other heuristics method and also for quality of our algorithm ANOVA's of output is constructed to analyse and evaluate the accuracy of the CPU time taken to determine near or optimal solution.

Congestion and oversaturated roads pose significant problems and create delays in every major city in the world. Before this problem can be addressed, we must know how much traffic is flowing over the links in the network. We transform a road network into a directed graph with a network flow function, and ask the question, “What subset of vertices (intersections) should be monitored such that knowledge of the flow passing through these vertices is sufficient to calculate the flow everywhere in the graph?” To minimize the cost of placing sensors, we seek the smallest number of monitored vertices. This is known as the Sensor Location Problem (SLP). We explore conditions under which a set of monitored vertices produces a unique solution to the problem and disprove a previous result published on the problem. Finally, we explore a matrix formulation of the problem and present cases when the flow can or cannot be calculated on the graph.

Portfolio selection is an example of decision making under conditions of uncertainty. In the face of an unknown future, fund managers make complex financial choices based on the investors perceptions and preferences towards risk and return. Since the seminal work of Markowitz, many studies have been published using his mean-variance (MV) model as a basis. These mathematical models of investor attitudes and asset return dynamics aid in the portfolio selection process. In this thesis we extend the MV model to include the cardinality constraints which limit the number of assets held in the portfolio and bounds on the proportion of an asset held (if any is held). We present our formulation based on the Markowitz MV model for rebalancing an existing portfolio subject to both fixed and variable transaction cost (the fee associated with trading). We determine and demonstrate the differences that arise in the shape of the trading portfolio and efficient frontiers when subject to non-cardinality and cardinality constrained transaction cost models. We apply our flexible heuristic algorithms of genetic algorithm, tabu search and simulated annealing to both the cardinality constrained and transaction cost models to solve problems using data from seven real world market indices. We show that by incorporating optimization into the generation of valid portfolios leads to good quality solutions in acceptable computational time. We illustrate this on problems from literature as well as on our own larger data sets.

Mobile cloud computing is a way of delegating complex algorithms from a mobile device to the cloud to complete the tasks quickly and save energy on the mobile device. However, the cloud may not be available or suitable for helping all the time. For example, in a battlefield scenario, the cloud may not be reachable. This work considers neighbouring devices as alternatives to the cloud for offloading computation and presents three key contributions, namely a comprehensive investigation of the trade-off between computation and communication, Multi-Objective Optimisation based approach to offloading, and Queuing Theory based algorithms that present the benefits of offloading to neighbours. Initially, the states of neighbouring devices are considered to be known and the decision of computation offloading is proposed as a multi-objective optimisation problem. Novel Pareto optimal solutions are proposed. The results on a simulated dataset show up to 30% increment in performance even when cloud computing is not available. However, information about the environment is seldom known completely. In Chapter 5, a realistic environment is considered such as delayed node state information and partially connected sensors. The network of sensors is modelled as a network of queues (Open Jackson network). The offloading problem is posed as minimum cost problem and solved using Linear solvers. In addition to the simulated dataset, the proposed solution is tested on a real computer vision dataset. The experiments on the random waypoint dataset showed up to 33% boost on performance whereas in the real dataset, exploiting the temporal and spatial distribution of the targets, a significantly higher increment in performance is achieved.

Due to an increasing awareness of the importance of sustainable energy use, multi-objective optimization problems for upper-level energy systems are continually being developed and improved. This paper focuses on the modeling and optimization of the Helsinki district heating system and establishing the basis for modeling the Finnish power network. The optimization of the district heating system is conducted for a twenty four hour winter demand period. Partial load behavior of the generators is included by introducing non-linear functions for costs, emissions, and the exergetic efficiency. A fuel cost sensitivity analysis is conducted on the system by considering ten combinations of fuel costs based on high, medium, and low prices for each fuel. The solution sets, called Pareto fronts, are evaluated by post-processing techniques in order to determine the best solution from the optimal set. Because units between some of objective functions are non-commensurable, objective values are normalized and weighted. The results indicate that for today\'s fuel prices the best solution includes a dominating usage of natural gas technologies, while if the price of natural gas is higher than other fuels, natural gas technologies are often not included in the best solution. All of the necessary costs, emissions, and operating information is provided for the the Finnish power network in order to employ a multi-objective optimization on the system. / Master of Science

This study is conducted with the aims to develop a new ranking method for multi-criteria decision making problem with conflicting criteria. Such a problem has a set of Pareto solutions, where the act of improving a value of one solution will result in depreciating some of the others. Thus, in this type of problem, there is no unique solution. However, out of many available options, the Decision Maker eventually has to choose only one solution. With this problem as the motivation, the current study develops a compromise ranking algorithm, namely a trade-off ranking method. The trade-off ranking method able to give a trade-off solution with the least compromise compared to other choices as the best solution. The properties of the algorithm are studied in the thesis on several test cases. The proposed method is compared against several multi-criteria decision making methods with ranking based on the distance measure, which are the TOPSIS, relative distance and VIKOR. The sensitivity analysis and uncertainty test are carried out to examine the methods robustness. A critical criteria analysis is also done to test for the most critical criterion in a multi-criteria problem. The decision making method is considered further in a fuzzy environment problem where the fuzzy trade-off ranking is developed and compared against existing fuzzy decision making methods.

Made available in DSpace on 2014-06-11T19:30:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-11-23Bitstream added on 2014-06-13T21:01:26Z : No. of bitstreams: 1 ochoapizzali_lf_dr_ilha.pdf: 1694440 bytes, checksum: e159d13557d3d0a89139b7565f849244 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Alban / Fundação de Ensino Pesquisa e Extensão de Ilha Solteira (FEPISA) / Neste trabalho, é apresentada uma análise em regime permanente que considera a avaliação de impactos técnicos tais como perdas elétricas, queda de tensão e níveis de curto-circuito, entre outros; utilizando dados de demanda e geração variáveis no tempo ao longo de um horizonte determinado. O objetivo é encontrar um conjunto de arranjos da GD (configurações) que levem ao melhor desempenho da rede de distribuição analisada, minimizando ou maximizando cada aspecto técnico segundo o interesse da empresa de distribuição. Dada a natureza combinatória deste problema, que requer uma ferramenta de otimização capaz de manipular múltiplos objetivos, os impactos técnicos serão avaliados simultaneamente utilizando uma metodologia baseada no conceito do Non-dominated Sorting Genetic Algorithm (NSGA), conduzindo a soluções mais reais e diversificadas para a tomada de decisões, conhecidas como soluções ótimas de Pareto. / In this work a steady-state analysis considering the assessment of technical impacts such as losses, voltage drop and short-circuit levels, among others; utilizing time-variant loads and generation within a specified horizon. The objective is to find a set of configurations that lead to the best performance of the distribution network under analysis, minimizing or maximizing each technical aspect according to the utility's concerns. Given the combinatorial nature of this problem, which requires an optimization tool able to handle multiple objectives, technical impacts will be assessed simultaneously through a methodology based on the non-dominated sorting genetic algorithm (NSGA). This approach leads to a more realistic and diversified set of solutions for taking decisions, known as Pareto-optimal solutions.

Orientador: Antonio Padilha Feltrin / Banca: Rubén Augusto Romero Lázaro / Banca: Dionízio Paschoareli Júnior / Banca: Gareth Harrison / Banca: Carmen Lucia Tancredo Borges / Resumo: Neste trabalho, é apresentada uma análise em regime permanente que considera a avaliação de impactos técnicos tais como perdas elétricas, queda de tensão e níveis de curto-circuito, entre outros; utilizando dados de demanda e geração variáveis no tempo ao longo de um horizonte determinado. O objetivo é encontrar um conjunto de arranjos da GD (configurações) que levem ao melhor desempenho da rede de distribuição analisada, minimizando ou maximizando cada aspecto técnico segundo o interesse da empresa de distribuição. Dada a natureza combinatória deste problema, que requer uma ferramenta de otimização capaz de manipular múltiplos objetivos, os impactos técnicos serão avaliados simultaneamente utilizando uma metodologia baseada no conceito do Non-dominated Sorting Genetic Algorithm (NSGA), conduzindo a soluções mais reais e diversificadas para a tomada de decisões, conhecidas como soluções ótimas de Pareto. / Abstract: In this work a steady-state analysis considering the assessment of technical impacts such as losses, voltage drop and short-circuit levels, among others; utilizing time-variant loads and generation within a specified horizon. The objective is to find a set of configurations that lead to the best performance of the distribution network under analysis, minimizing or maximizing each technical aspect according to the utility's concerns. Given the combinatorial nature of this problem, which requires an optimization tool able to handle multiple objectives, technical impacts will be assessed simultaneously through a methodology based on the non-dominated sorting genetic algorithm (NSGA). This approach leads to a more realistic and diversified set of solutions for taking decisions, known as Pareto-optimal solutions. / Doutor

Cette recherche est une étude des conditions sociales, économiques, culturelles de la production cinématographique en Afrique de l’ouest francophone en général, au Burkina Faso et au Sénégal en particulier, dans un contexte de mondialisation des images et de difficultés structurelles de la filière cinématographique.Notre objectif est de mettre en exergue les pratiques et les stratégies en termes de solutions optimales des réalisateurs de films à travers une analyse institutionnelle, historique et socioculturelle des systèmes de contraintes qui leur donnent naissance et les dynamisent. Les systèmes de contraintes sont une combinaison d’un ensemble de variables (paramètres et inconnues) et de contraintes, à prendre en compte par le réalisateur de films burkinabé et sénégalais car pouvant influencer, déterminer ou optimiser les solutions mises en place.Le point de départ de notre réflexion a été de considérer que l’analyse de ces pratiques et stratégies de réalisateurs de films burkinabés et sénégalais – acteurs rationnels évoluant dans un contexte contraignant sous l’angle boudonien – est indissociable de l’analyse des conditions sociales et du système d’interactions quiparticipent à leur mise en oeuvre et les légitiment. De ce fait, afin de cerner notre objet dans ses multiples facettes, plusieurs domaines sociologiques ont été mobilisés tout au long de cette recherche qui s’inscrit, d’unepart, dans la sociologie des professions, et d’autre part dans la sociologie des arts. Notre démarche emprunte ainsi son épistémologie et sa théorie à la sociologie des acteurs notamment les principes de la théorie générale dela rationalité. Nous avons, par ailleurs, fait appel accessoirement à la sociologie du cinéma, à l’économie de la culture et à la politique culturelle.Cette approche socio-anthropologique s’inscrit dans une démarche monographique et comparative entre deux pays de traditions cinématographiques différentes à savoir le Burkina Faso et le Sénégal. Un corpus exhaustif de45 réalisateurs de films a été établi par rapport à trois critères d’inclusion et de circonscription à notre population d’enquête afin d’offrir une comparaison, en termes de trajectoire ; de parcours biographique ; de conditions de travail ; de structures de références et d’activités hors-travail. Un premier niveau de comparaison a été effectué entre les réalisateurs de films de chaque pays, puis un deuxième sur l’ensemble de population afin de mesurer les similitudes et les divergences de parcours et de carrières.Notre approche donne lieu à une analyse qualitative du discours de notre population d’enquête afin de rendre compte des conditions de production. Elle s’appuie également sur une interprétation quantitative dans la mesure où nos données ont été utilisées comme des outils statistiques. Nous avons eu recours aux donnéesstatistiques de seconde main et établi un corpus filmique, qui comprend essentiellement les films de notre population d’étude, ils ont été utilisés en complément à l’éclairage de notre analyse.Et pourtant, derrière la rhétorique de la crise de la cinématographie ouest-africaine francophone, ils tournent !Notre thèse montre qu’en dépit de ce contexte de rareté, de précarité et de contrainte, les réalisateurs de films burkinabés et sénégalais mobilisent les ressources, établissent des coopérations pour continuer à exister en tantque groupe professionnel. Ils développent des plans d’organisation à travers des modèles économiques leur permettant de proposer une offre pertinente, tout en leur garantissant la viabilité de leurs activités dans le temps.Cette thèse offre, en définitive, une réflexion sur les enjeux de la production cinématographique et les mutationsau sein du groupe professionnel des réalisateurs de films burkinabés et sénégalais. Elle entend aussi reconceptualiser le cinéma ouest-africain francophone. / This thesis is a study of the social, economic and cultural conditions of the filmproduction in the West French speaking part of Africa, more particularly in Burkina Faso and Senegal in a world of images globalization facing structural difficulties of the film industry.Our main objective here, is to emphasize both customs and strategies regarding optimal solutions offered by the film directors threw an institutional, historical and sociocultural analysis of the constraints systems who create and empower them. Constraints systems are a combination of a set of variables (parameters and unknown) and constraints that can influence, determine or even maximize the solutions the film director work.The starting point of our reflexion was to consider that the analysis of the practices and strategies made by the senegalese and burkinabé film producers - rational actors evolving in a restrictive environment according to Boudon’s point of view - cannot be isolated from the social conditions and system of interaction who help their implementation and legitimate them. Therefore, to better understand our subject, several sociological areas were mobilized throughout the research which is forming part, first, of the sociology of the professions and then, of the sociology of arts. Thus, our approach is using its epistemology and theory of the sociology of actors, particularly the general theory of rationality principles. Furthermore, wedid use secondarily the sociology of film, the economy of culture and the cultural policy.This socio anthropological approach is part of a monographic and comparative processbetween two countries with different film custom namely Burkina Faso and Senegal. Acomplete body of 45 film producers was established based on three criteria of inclusion and district to the survey sample in order to make a comparison between biographical sketch, working conditions, reference bodies and non-working activities. A comparison was first made between the film producers of each countries and secondly on the overall population so as to bring out their journey and career similarities and differences.Our approach results in a qualitative analysis of our survey sample’ speech to report on the production’s conditions. It also rely on a quantitative interpretation considering the fact that our figures were used as statistical tools. We had recourse to second-hand statistical data and established a corpus of film mainly made of the survey population’s movies. We used them as a complement to contribute to the analysis.However, behind the rhetoric of the west african french-speaking cinematographic crisis, they still need quiet on the set! Our thesis shows that despite the context of scarcity, precarity and constraint, the burkinabé and senegalese film directors are still mobilising resources and establishing cooperation to keep on existing as a occupational group. They are developing organisation plans throughout economic models to make their offer more relevant by ensuring their activities viability over time.Ultimately, this thesis is a comprehensive analysis on the film production stakes and transformations within the burkinabé and senegalese film director occupational group. It also intends to reconceptualize the west african french speaking cinema.

Face aux exigences concurrentielles et économiques actuelles dans le secteur automobile, l'emboutissage a l'avantage, comme étant un procédé de mise en forme par grande déformation, de produire, en grandes cadences, des pièces de meilleure qualité géométrique par rapport aux autres procédés de fabrication mécanique. Cependant, il présente des difficultés de mise en œuvre, cette dernière s'effectue généralement dans les entreprises par la méthode classique d'essai-erreur, une méthode longue et très coûteuse. Dans la recherche, le recours à la simulation du procédé par la méthode des éléments finis est une alternative. Elle est actuellement une des innovations technologiques qui cherche à réduire le coût de production et de réalisation des outillages et facilite l'analyse et la résolution des problèmes liés au procédé. Dans le cadre de cette thèse, l'objectif est de prédire et de prévenir, particulièrement, le retour élastique et la rupture. Ces deux problèmes sont les plus répandus en emboutissage et présentent une difficulté en optimisation puisqu'ils sont antagonistes. Une pièce mise en forme par emboutissage à l'aide d'un poinçon sous forme de croix a fait l'objet de l'étude. Nous avons envisagé, d'abord, d'analyser la sensibilité des deux phénomènes concernés par rapport à deux paramètres caractéristiques du procédé d'emboutissage (l'épaisseur du flan initial et de la vitesse du poinçon), puis par rapport à quatre (l'épaisseur du flan initial, de la vitesse du poinçon, l'effort du serre flan et le coefficient du frottement) et finalement par rapport à la forme du contour du flan. Le recours à des méta-modèles pour optimiser les deux critères était nécessaire. / The processing of sheet metal forming is of vital importance to a large range of industries as production of car bodies, cans, appliances, etc. It generates complex and precise parts. Although, it is an involved technology combining elastic-plastic bending and stretch deformation of the workpiece. These deformations can lead to undesirable problems in the desired shape and performance of the stamped. To perform a successful stamping process and avoid shape deviations such as springback and failure defects, process variables should be optimized.In the present work, the objective is the prediction and the prevention of, especially, springback and failure. These two phenomena are the most common problems in stamping process that present much difficulties in optimization since they are two conflicting objectives. The forming test studied in this thesis concern the stamping of an industrial workpiece stamped with a cross punch. To solve this optimization problem, the approach chosen was based on the hybridization of an heuristic and a direct descent method. This hybridization is designed to take advantage from both disciplines, stochastic and deterministic, in order to improve the robustness and the efficiency of the hybrid algorithm. For the multi-objective problem, we adopt methods based on the identification of Pareto front. To have a compromise between the convergence towards the front and the manner in which the solutions are distributed, we choose two appropriate methods. This methods have the capability to capture the Pareto front and have the advantage of generating a set of Pareto-optimal solutions uniformly spaced. The last property can be of important and practical.