Made available in DSpace on 2016-06-02T19:06:15Z (GMT). No. of bitstreams: 1 6235.pdf: 6898238 bytes, checksum: 058a3b75f03de2058255b7fa7db30dac (MD5) Previous issue date: 2014-05-22 / Financiadora de Estudos e Projetos / Visual servoing is a technique that uses computer vision to acquire visual information (by camera) and a control system with closed loop circuit to control robots. One typical application of visual servoing is tracking objects on conveyors in industrial environments. Visual servoing has the advantage of obtaining a large amount of information from the environment and greater flexibility in operations than other types of sensors. A disadvantage are the delays, known as dead-times or time-delays that can occur during the treatment of visual information in computer vision tasks or other tasks of the control system that need large processing capacity. The dead-times in visual servoing applied in industrial operations such as in the tracking of objects on conveyors are critical and can negatively affect production capacity in manufacturing environments. Some methodogies can be found in the literature for this problem and some of these methodologies are often based on the Kalman filter. In this work a technique was selected based on the formulation of the Kalman filter that already had a study on the prediction of future pose of objects with linear motion. This methodology has been studied in detail, tested and analyzed through simulations for other motions and some applications. Three types of experiments were generated: one for different types of motions and two others applied in different types of signals in the velocity control systems. The results from the motion of the object shown that the technique is able to estimate the future pose of objects with linear motion and smooth curves, but it is inefficient for drastic changes in motion. With respect to the signal to be filtered in the velocity control, the methodogy has been shown applicable (with motions conditions) only in the estimation of pose of the object after the occurrence of dead-times caused by computer vision and this information is subsequently used to calculate the future error of the object related to the robotic manipulator used to calculate the velocity of the robot. The trying to apply the methodogy directly on the error used to calculate the velocity to be applied to the robot did not produce good results. With the results the methodogy can be applied for object tracking with linear motion and smooth curves as in the case of objects transported by conveyors in industrial environments. / Servovisao e uma tecnica que utiliza visao computacional para obter informacoes visuais (atraves de camera) e um sistema de controle com circuito em malha fechada para controlar robos. Uma das aplicacoes tipicas de servovisao e no rastreamento de objetos sobre esteiras transportadoras em ambientes industriais. Servovisao possui a vantagem em relacao a outros tipos de sensores de permitir a obtencao de um grande numero de informacoes a partir do ambiente e maior flexibilidade nas operacoes. Uma desvantagem sao os atrasos conhecidos como dead-times ou time-delays que podem ocorrer durante o tratamento de informacoes visuais nas tarefas de visao computacional ou em outras tarefas do sistema de controle que necessitam de grande capacidade de processamento. Os dead-times em servovisao aplicada em operacoes industriais como no rastreamento de objetos em esteiras transportadoras sao criticos e podem afetar negativamente na capacidade de producao em ambientes de manufatura. Algumas metodologias podem ser encontradas na literatura para esse tipo de problema sendo muitas vezes baseadas no filtro de Kalman. Nesse trabalho foi selecionada uma metodologia baseada na formulacao do filtro de Kalman que ja possui um estudo na previsao futura de pose de objetos com movimentacao linear. Essa metodologia foi estudada detalhadamente, testada atraves de simulacoes e analisada sobre outros tipos de movimentos e algumas aplicacoes. No total foram gerados tres tipos de experimentos: um para diferentes tipos de movimentacao e outros dois aplicados em diferentes tipos de sinais no controlador de velocidades. Os resultados a partir da movimentacao do objeto demonstraram que o metodo e capaz de estimar a pose futura de objetos com movimento linear e com curvas suaves, porem e ineficiente para alteracoes drasticas no movimento. Com relacao ao sinal a ser filtrado no controlador de velocidades a metodologia se demonstrou aplicavel (com as condicoes de movimento) somente na estimativa da pose do objeto apos a ocorrencia de dead-times causados por visao computacional e posteriormente essa informacao e utilizada para calcular o erro futuro do objeto em relacao ao manipulador robotico utilizado no calculo da velocidade do robo. A tentativa de aplicacao da tecnica diretamente no erro utilizado no calculo da velocidade a ser aplicada ao robo nao apresentou bons resultados. Com os resultados obtidos a metodologia se demonstrou eficiente para o rastreamento de objetos de forma linear e curvas suaves como no caso de objetos transportados por esteiras em ambientes industriais.

This thesis deals with model predictive control principally Based Predictive Control (MPC). The first part describes the principle of predictive control, cost function, the choice of a constraints in regulation and the choice of weights. In the next section is an analysis system: a system with non-minimal phase (control water turbine), oscillating systems (trolley frame control) and system with a time-delay . In all of these systems is performed classical feedback control using PID control and concurrently regulation with the MPC. MPC is selected as the solution fy Mathworks Model Predictive Control Toolbox and Simulink. The results are then analyzed using the criteria of quality control.

This study addresses the specific barriers related to time delays in the treatment of patients who suffered acute myocardial infarction at the Al Ain Hospital accident and emergency unit in the United Arab Emirates. A comprehensive background of the UAE is given for the benefit of students who have limited access to the background and challenges facing medical and nursing personnel in providing thrombolythic therapy to patients who suffered from acute myocardial infarction. The study will contribute to the continuous quality management and improvement of overall nursing and medical care of the AMI patient who is eligible for thrombolysis. An extensive literature review addresses the clinical manifestations and treatment of the patient suffering from AMI as well as the adverse effects of time delays in treatment during the acute phase of the disease. The researcher selected a quantitative, non-experimental descriptive and retrospective study. Data was collected by a structured instrument to gather the desired responses from the files of 457 selected patients admitted to the Al Ain Hospital. This study emphasizes the need to improve patient care by all health care personnel in an accident and emergency unit to prevent the delays in treatment in life threatening conditions such as myocardial infarction ensuring optimal and prompt time to thrombolyse. The improvement of awareness and commitment by health care providers such as nurses, doctors and ambulance personnel, can be achieved through education and training, commitment and dedication, absolute cooperation, collaboration and constant update on performance. Regular audits are essential with regard to door-to-needle time and performance of all health care providers. This study ultimately show that time constrains in attending to patients presenting with myocardial infarction should be addressed in utmost urgency. / Health Studies / M. A. (Health Studies)

This paper deals with the consensus problem under communication network inducing delays. It is well-known that introducing a delay leads in general to a reduction of the performance or to instability due to the fact that timedelay systems are infinite dimensional. For instance, the set of initial conditions of a time-delay system is not a vector but a function taken in an interval. Therefore, investigating the effect of time-delays in the consensus problem is an important issue. In the present paper, we assume that each agent receives instantaneously its own state information but receives the state information from its neighbors after a constant delay. Two stability criteria are provided based on the frequency approach and on Lyapunov-Krasovskii techniques given in terms of LMI. An analytic expression of the consensus equilibrium which depends on the delay and on the initial conditions taken in an interval is derived. The efficiency of the method is tested for different network communication schemes. / <p>QC 20110120</p>

This study addresses the specific barriers related to time delays in the treatment of patients who suffered acute myocardial infarction at the Al Ain Hospital accident and emergency unit in the United Arab Emirates. A comprehensive background of the UAE is given for the benefit of students who have limited access to the background and challenges facing medical and nursing personnel in providing thrombolythic therapy to patients who suffered from acute myocardial infarction. The study will contribute to the continuous quality management and improvement of overall nursing and medical care of the AMI patient who is eligible for thrombolysis. An extensive literature review addresses the clinical manifestations and treatment of the patient suffering from AMI as well as the adverse effects of time delays in treatment during the acute phase of the disease. The researcher selected a quantitative, non-experimental descriptive and retrospective study. Data was collected by a structured instrument to gather the desired responses from the files of 457 selected patients admitted to the Al Ain Hospital. This study emphasizes the need to improve patient care by all health care personnel in an accident and emergency unit to prevent the delays in treatment in life threatening conditions such as myocardial infarction ensuring optimal and prompt time to thrombolyse. The improvement of awareness and commitment by health care providers such as nurses, doctors and ambulance personnel, can be achieved through education and training, commitment and dedication, absolute cooperation, collaboration and constant update on performance. Regular audits are essential with regard to door-to-needle time and performance of all health care providers. This study ultimately show that time constrains in attending to patients presenting with myocardial infarction should be addressed in utmost urgency. / Health Studies / M. A. (Health Studies)

Dans le cadre de cette thèse, nous traitons le problème de flow-shop à deux machines avec temps de transport où l’objectif consiste à minimiser le temps de complétion maximal. Dans un premier temps, nous nous sommes intéressés à la modélisation de ce problème. Nous avons proposé plusieurs programmes linéaires en nombres entiers. En particulier, nous avons introduit une formulation linéaire basée sur une généralisation non triviale du modèle d’affectation pour le cas où les durées des opérations sur une même machine sont identiques. Dans un deuxième temps, nous avons élargi la portée de ces formulations mathématiques pour développer plusieurs bornes inférieures et un algorithme exact basé sur la méthode de coupe et branchement (Branch-and-Cut). En effet, un ensemble d’inégalités valides a été considéré afin d’améliorer la relaxation linéaire de ces programmes et d’accélérer leur convergence. Ces inégalités sont basées sur la proposition de nouvelles règles de dominance et l’identification de sous-instances faciles à résoudre. L’identification de ces sous-instances revient à déterminer les cliques maximales dans un graphe d’intervalles. En plus des inégalités valides, la méthode exacte proposée inclut la considération d’une méthode heuristique et d’une procédure visant à élaguer les nœuds. Enfin, nous avons proposé un algorithme par séparation et évaluation (Branch-and-Bound) pour lequel, nous avons introduit des règles de dominance et une méthode heuristique basée sur la recherche locale. Nos expérimentations montrent l’efficacité de nos approches qui dominent celles de la littérature. Ces expérimentations ont été conduites sur plusieurs classes d’instances qui incluent celles de la littérature, ainsi que des nouvelles classes d’instances où les algorithmes de la littérature se sont montrés peu efficaces. / In this thesis, we study the two-machine flow-shop problem with time delays in order to minimize the makespan. First, we propose a set of Mixed Integer Programming (MIP) formulations for the problem. In particular, we introduce a new compact mathematical formulation for the case where operations are identical per machine. The proposed mathematical formulations are then used to develop lower bounds and a branch-and-cut method. A set of valid inequalities is proposed in order to improve the linear relaxation of the MIPs. These inequalities are based on proposing new dominance rules and computing optimal solutions of polynomial-time-solvable sub-instances. These sub-instances are extracted by computing all maximal cliques on a particular Interval graph. In addition to the valid inequalities, the branch-and-cut method includes the consideration of a heuristic method and a node pruning procedure. Finally, we propose a branch-and-bound method. For which, we introduce a local search-based heuristic and dominance rules. Experiments were conducted on a variety of classes of instances including both literature and new proposed ones. These experiments show the efficiency of our approaches that outperform the leading methods published in the research literature.

Cette thèse traite de l'identification des paramètres du point de vue de l'optimisation et du contrôle de suivi distribué des systèmes multi-agents d'ordre fractionnaire (FOMASs) en tenant compte des retards, des perturbations externes, de la non-linéarité inhérente, des incertitudes des paramètres et de l'hétérogénéité dans le cadre d'une topologie de communication fixe non dirigée / dirigée. Plusieurs contrôleurs efficaces sont conçus pour réaliser avec succès le contrôle de suivi distribué des FOMASs dans différentes conditions. Plusieurs types d'algorithmes d'optimisation de l'intelligence artificielle et leurs versions modifiées sont appliquées pour identifier les paramètres inconnus des FOMASs avec une grande précision, une convergence rapide et une grande robustesse. Il est à noter que cette thèse fournit un lien prometteur entre la technique d'intelligence artificielle et le contrôle distribué. / This thesis deals with the parameter identification from the viewpoint of optimization and distributed tracking control of fractional-order multi-agent systems (FOMASs) considering time delays, external disturbances, inherent nonlinearity, parameters uncertainties, and heterogeneity under fixed undirected/directed communication topology. Several efficient controllers are designed to achieve the distributed tracking control of FOMASs successfully under different conditions. Several kinds of artificial intelligence optimization algorithms andtheir modified versions are applied to identify the unknown parameters of the FOMASs with high accuracy, fast convergence and strong robustness. It should be noted that this thesis provides a promising link between the artificial intelligence technique and distributed control.

Au cours des dernières décennies, la mondialisation a joué un rôle crucial dans l'évolution de l'économie mondiale et du mode de vie des populations. Elle a largement contribué à la croissance économique de nombreux pays grâce à l'essor des échanges commerciaux, des investissements et de la création d'emplois , entre autres. Cependant, si la mondialisation a apporté de nombreux avantages, elle a également rendu les pays plus vulnérables aux crises. Elle a aussi soulevé des défis en matière de coordinations de politiques économiques des groupes de pays souverains. Cette thèse, composée de trois chapitres, se penche sur certaines questions macroéconomiques liées à l'économie internationale. Le premier chapitre présente une méthode permettant d'analyser les canaux de propagation du cycle économique au sein d'une économie et entre les pays. Le deuxième chapitre aborde la conception de règles budgétaires pour les économies intégrées au sein d'une union économique et monétaire. Enfin, le dernier chapitre évalue l'impact des obstacles routiers tels que les barrages, les retards et la corruption sur l'intégration commerciale régionale en Afrique de l'Ouest. Dans le premier chapitre, j'ai développé une méthode visant à orienter les chercheurs dans la spécification améliorée de leurs modèles quantitatifs lors de l'étude du cycle économique international. Les orientations découlent de l'application de la comptabilité des cycles économiques, en se basant sur un modèle prototype. Ce modèle prototype est construit à partir d'un modèle de croissance internationale auquel sont intégrés des «wedges» qui captent les frictions et distorsions présentes dans l'économie. Pour chaque pays, j'ai pris en compte les «wedges» suivants : l'efficacité technologique, les distorsions sur le marché du travail, l'investissement, les dépenses gouvernementales, les préférences et les échanges d'actifs étrangers. J'ai ensuite illustré cette méthode en l'appliquant aux États-Unis et au Canada pendant la grande récession de 2007-2008. Mes résultats indiquent que les ralentissements économiques observés dans les deux pays au cours de cette période étaient principalement dus aux distorsions de l'investissement, aux distorsions sur le marché du travail et à celles de l'efficacité technologique aux États-Unis, tandis que les distorsions de l'investissement au Canada ne jouaient qu'un rôle secondaire. Ces résultats suggèrent que la crise est partie des États-Unis pour se propager ensuite au Canada. Le deuxième chapitre se concentre sur la conception de la règle budgétaire au sein d'une union économique, avec une application à l'Union économique et monétaire ouest-africaine (UEMOA), qui possède un marché des capitaux intégré et une règle budgétaire commune. Je présente des faits sur l'existence d'une hétérogénéité significative des recettes, des dépenses et de la dette publiques parmi les pays de l'UEMOA. Dans ce chapitre, j'effectue une analyse quantitative de la règle budgétaire au sein de l'UEMOA et propose une réforme optimale en utilisant un cadre théorique qui modélise la politique fiscale des gouvernements confrontés à des chocs et ayant des préférences temporelles biaisées vers le présent. Le modèle met en évidence un compromis entre la flexibilité du gouvernement pour faire face aux chocs et l'engagement à limiter les incitations à un endettement excessif. Les résultats montrent que la règle actuelle de limitation du déficit à 3 \%, appliquée uniformément à tous les pays de l'UEMOA, améliore le bien-être des citoyens par rapport à un scénario sans règle budgétaire. Cependant, l'adoption de règles budgétaires spécifiques à chaque pays conduirait à une amélioration au sens de Pareto par rapport à la règle uniforme actuelle. La limite optimale du déficit pour chaque pays dépendrait de la volatilité des chocs affectant ses besoins de dépenses ainsi que des frictions politico-économiques et monétaires propres à son gouvernement. En outre, en imposant une règle budgétaire uniforme à tous ses membres, l'UEMOA renonce à 24 \% des gains de bien-être qui pourraient être obtenus grâce à l'adoption de règles budgétaires spécifiques à chaque pays. En résumé, mes résultats démontrent que bien que l'UEMOA bénéficie d'une règle budgétaire commune, une règle sur mesure tenant compte des caractéristiques spécifiques de chaque pays membre améliorerait encore davantage le bien-être général. Le troisième chapitre (co-écrit avec Idossou Marius Adom) examine les effets des barrages routiers, des retards et de la corruption le long des routes interétatiques sur l'intégration commerciale régionale en Afrique de l'Ouest. Il est bien connu que le commerce régional en Afrique est relativement faible par rapport à d'autres régions du monde. Dans cet article, nous utilisons les rapports sur «l'amélioration de la gouvernance des transports routiers» (IRTG) pour construire une nouvelle base de données mesurant les barrages routiers, les retards et les pots-de-vin liés au commerce sur huit routes interétatiques en Afrique de l'Ouest entre 2006 et 2013. Notre objectif est d'étudier leurs effets sur le commerce bilatéral dans la région. Ces routes interétatiques relient trois pays enclavés -- le Burkina Faso, le Niger et le Mali -- à d'autres pays côtiers. Nos résultats montrent que les barrages routiers, les retards et la corruption sont des problèmes récurrents sur ces routes. Pendant le transport des marchandises, les camions sont soumis à plus de 25 contrôles, subissent des retards de plus de 5 heures et sont contraints de verser des pots-de-vin allant de 45 à 115 dollars américains. Nos analyses empiriques révèlent que les retards entravent considérablement le commerce bilatéral entre les pays connectés, tandis que l'effet positif de la corruption semble correspondre à celui de la théorie du «grease the wheels». / Globalization has been an important force in shaping the world economy and the way people live their lives in the past few decades. It has had sizable importance in the economic growth of many countries through the increase in trade, investment, new job creation, etc. While globalization has brought many benefits, it has also created many challenges such as the increase of the vulnerability of countries to crises, and the challenges of policy management of groups of sovereign countries. This dissertation, composed of three chapters, investigates some macroeconomic issues of the international economy. The first chapter proposes a method to access the channel through which the business cycle propagates to an economy and across countries. The second chapter investigates the fiscal rule design for integrated economies constituted in an economic and monetary union. The last chapter evaluates the effect of roadblocks, time delays, and bribes on interstate roads on regional trade integration in West Africa. In the first chapter, I have developed a method that can provide insights to researchers to better specify their quantitative models in international business cycle studies. The guidance comes from the application of an accounting procedure based on a prototype model of international growth that includes wedges capturing all the potential frictions and distortions of markets. For each country, I include an efficiency wedge, labor wedge, investment wedge, government wedge, preference wedge, and foreign asset wedge. I then demonstrate the method by applying it to the US and Canada during the Great Recession (2007-2008). I found that the economic downturns in both countries during this period were primarily due to the US investment wedge, US labor wedge, and US efficiency wedge, with the Canada investment wedge playing a secondary role. These results suggest that the crisis originated in the US and was propagated to Canada. The second chapter investigates the fiscal rule design for an economic union with an application to the West African Economic and Monetary Union (WAEMU) which has an integrated capital market and a common fiscal rule. I document a significant heterogeneity in government revenue, spending, and debt across WAEMU countries. Then, in this chapter, I present a quantitative analysis of the fiscal rule in WAEMU and propose an optimal reform using a theoretical framework that models fiscal policy under present-biased governments facing shocks to their fiscal needs. The model highlights a trade-off between government flexibility in responding to shocks and a commitment to limit the incentive to overborrow. I find that the current 3\% deficit limit rule, which is uniform across all WAEMU countries, improves welfare for the citizens of all countries compared to a scenario with no fiscal rule. However, country-specific fiscal rules would lead to a Pareto improvement over the current uniform rule. The optimal deficit limit for each country would depend on the volatility of the shocks to its spending needs and the strength of the political-economic and monetary-economic frictions of its government. In addition, by imposing a uniform fiscal rule on all members, WAEMU foregoes 24\% of the welfare gains that could be achieved with a country-specific fiscal rule. In summary, I show that while WAEMU countries benefit from having a common fiscal rule, a tailored approach that considers the specific characteristics of each member country would enhance welfare even further. The third chapter (\emph{co-authored with Idossou Marius Adom}) explores the effects of roadblocks, time delays, and bribes along interstate roads on the regional trade integration in West Africa. Indeed, it is a well-known fact that regional trade within Africa is low compared to other regions in the world. In this paper, we rely on the Improved Road-Transport Governance reports to construct a novel data set that measures trade-related roadblocks, time delays, and bribes on eight interstate roads in Western Africa between 2006 and 2013 to investigate their effects on bilateral trade in the region. These interstate roads connect three landlocked countries -- Burkina Faso, Niger, and Mali -- to other coastal countries. We document that roadblocks, delays, and bribes are pervasive on the roads. During goods transportation, trucks experience up to more than 25 controls, are delayed by up to more than 5 hours, and pay between 45 and 115 US dollars bribe. Our empirical analyses show that the delays seriously impede bilateral trade between the connected countries while corruption tends to match the ``grease the wheels'' theory.