Simulation is an important tool for prediction and assessment of the behavior of complex systems and situations. The importance of simulation has increased tremendously during the last few decades, mainly because the rapid pace of development in the field of electronics has turned the computer from a costly and obscure piece of equipment to a cheap ubiquitous tool which is now an integral part of our daily lives. While such technological improvements make it easier to analyze well-understood deterministic systems, increase in speed and storage capacity alone are not enough when simulating situations where human beings and their behavior are an integral part of the system being studied. The problem with simulation of intelligent entities is that intelligence is still not well understood and it seems that the field of Artificial Intelligence (AI) has a long way to go before we get computers to think like humans. Behavior-based agent modeling has been proposed in mid-80's as one of the alternatives to the classical AI approach. While used mainly for the control of specialized robotic vehicles with very specific sensory capabilities and limited intelligence, we believe that a behavior-based approach to modeling generic autonomous agents in complex environments can provide promising results. To this end, we are investigating a behavior-based model for controlling groups of collaborating and competing agents in a geographic terrain. In this thesis, we are focusing on scenarios of military nature, where agents can move within the environment and adversaries can eliminate each other through use of weapons. Different aspects of agent behavior like navigation to a goal or staying in group formation, are implemented by distinct behavior modules and the final observed behavior for each agent is an emergent property of the combination of simple behaviors and their interaction with the environment. Our experiments show that while such an approach is quite efficient in terms of computational power, it has some major drawbacks. One of the problems is that reactive behavior-based navigation algorithms are not well suited for environments with complex mobility constraints where they tend to perform much worse than proper path planning. This problem represents an important research question, especially when it is considered that most of the modern military conflicts and operations occur in urban environments. One of the contributions of this thesis is a novel approach to reactive navigation where goals and terrain information are fused based on the idea of transforming a terrain with obstacles into a virtual obstacle-free terrain. Experimental results show that our approach can successfully combine the low run-time computational complexity of reactive methods with the high success rates of classical path planning. Another interesting research problem is how to deal with the unpredictable nature of emergent behavior. It is not uncommon to have situations where an outcome diverges significantly from the intended behavior of the agents due to highly complex nonlinear interactions with other agents or the environment itself. Chances of devising a formal way to predict and avoid such abnormalities are slim at best, mostly because such complex systems tend to be be chaotic in nature. Instead, we focus on detection of deviations through tracking group behavior which is a key component of the total situation awareness capability required by modern technology-oriented and network-centric warfare. We have designed a simple and efficient clustering algorithm for tracking of groups of agent suitable for both spatial and behavioral domain. We also show how to detect certain events of interest based on a temporal analysis of the evolution of discovered clusters.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

A aussi paru sous forme de thèse: Siegen, Univ., 2006.

Made available in DSpace on 2014-12-17T14:08:56Z (GMT). No. of bitstreams: 1 HeloizeSP_DISSERT.pdf: 5210676 bytes, checksum: 2206731cf8d9981475df85f8e57f31d2 (MD5) Previous issue date: 2014-03-06 / The occurrence of heavy oil reservoirs have increased substantially and, due to the high viscosity characteristic of this type of oil, conventional recovery methods can not be applied. Thermal methods have been studied for the recovery of this type of oil, with a main objective to reduce its viscosity, by increasing the reservoir temperature, favoring the mobility of the oil and allowing an increasing in the productivity rate of the fields. In situ combustion (ISC) is a thermal recovery method in which heat is produced inside the reservoir by the combustion of part of the oil with injected oxygen, contrasting with the injection of fluid that is heated in the surface for subsequent injection, which leads to loss heat during the trajectory to the reservoir. The ISC is a favorable method for recovery of heavy oil, but it is still difficult to be field implemented. This work had as an objective the parametric analysis of ISC process applied to a semi-synthetic reservoir with characteristics of the Brazilian Northeast reservoirs using vertical production and vertical injection wells, as the air flow injection and the wells completions. For the analysis, was used a commercial program for simulation of oil reservoirs using thermal processes, called Steam, Thermal and Advanced Processes Reservoir Simulator (STARS) from Computer Modelling Group (CMG). From the results it was possible to analyze the efficiency of the ISC process in heavy oil reservoirs by increasing the reservoir temperature, providing a large decrease in oil viscosity, increasing its mobility inside the reservoir, as well as the improvement in the quality of this oil and therefore increasing significantly its recovered fraction. Among the analyzed parameters, the flow rate of air injection was the one which had greater influence in ISC, obtaining higher recovery factor the higher is the flow rate of injection, due to the greater amount of oxygen while ensuring the maintenance of the combustion front / A ocorr?ncia de ?leos pesados e ultrapesados v?m aumentando sensivelmente e, devido ? alta viscosidade caracter?stica deste tipo de ?leo, n?o podem ser aplicados os m?todos convencionais de recupera??o. M?todos t?rmicos v?m sendo estudados para recupera??o deste tipo de ?leo, tendo como principal objetivo reduzir a sua viscosidade atrav?s do aumento da temperatura do reservat?rio, favorecendo a mobilidade do ?leo e permitindo um aumento no ?ndice de produtividade dos campos. A Combust?o in situ (CIS) ? um m?todo t?rmico de recupera??o em que o calor ? produzido dentro do reservat?rio pela combust?o de parte do ?leo com oxig?nio injetado, contrastando com a inje??o de fluido aquecido ainda na superf?cie para posterior inje??o, o que acarreta perda de calor durante o trajeto ao reservat?rio. A CIS ? um m?todo prop?cio para recupera??o de ?leo pesado, por?m ainda ? complexo de ser implementado. Este trabalho teve como objetivo a an?lise param?trica do processo CIS aplicado a um reservat?rio semissint?tico com caracter?sticas do Nordeste Brasileiro utilizando po?os verticais de produ??o e inje??o, assim como a vaz?o de inje??o de ar e as completa??es dos po?os. Para an?lise do m?todo foi utilizado um programa comercial de simula??o de reservat?rios de petr?leo usando processos t?rmicos, denominado Steam, Thermal and Advanced Processes Reservoir Simulator (STARS) do Computer Modelling Group (CMG). A partir dos resultados obtidos foi poss?vel comprovar a efici?ncia do processo CIS em reservat?rios de ?leo pesado atrav?s do aumento da temperatura do reservat?rio, promovendo uma grande diminui??o na viscosidade do ?leo, aumentando sua mobilidade no interior do reservat?rio, assim como a melhora na qualidade desse ?leo e aumentando assim, significativamente a sua fra??o recuperada. Dentre os par?metros analisados, a vaz?o de inje??o de ar foi a que apresentou maior influ?ncia no processo CIS, obtendo maior fator de recupera??o quanto maior a vaz?o de inje??o, sendo devido a maior quantidade de oxig?nio garantindo a manuten??o da frente de combust?o

Made available in DSpace on 2014-12-17T14:09:14Z (GMT). No. of bitstreams: 1 MarcosAFR_TESE.pdf: 4983695 bytes, checksum: 6cb8867b58e49a5dd6efc85191c6fa49 (MD5) Previous issue date: 2012-09-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Many of hydrocarbon reserves existing in the world are formed by heavy oils (?API between 10 and 20). Moreover, several heavy oil fields are mature and, thus, offer great challenges for oil industry. Among the thermal methods used to recover these resources, steamflooding has been the main economically viable alternative. Latent heat carried by steam heats the reservoir, reducing oil viscosity and facilitating the production. This method has many variations and has been studied both theoretically and experimentally (in pilot projects and in full field applications). In order to increase oil recovery and reduce steam injection costs, the injection of alternative fluid has been used on three main ways: alternately, co-injected with steam and after steam injection interruption. The main objective of these injection systems is to reduce the amount of heat supplied to the reservoir, using cheaper fluids and maintaining the same oil production levels. This works discusses the use of carbon dioxide, nitrogen, methane and water as an alternative fluid to the steam. The analyzed parameters were oil recoveries and net cumulative oil productions. The reservoir simulation model corresponds to an oil reservoir of 100 m x 100 m x 28 m size, on a Cartesian coordinates system (x, y and z directions). It is a semi synthetic model with some reservoir data similar to those found in Brazilian Potiguar Basin. All studied cases were done using the simulator STARS from CMG (Computer Modelling Group, version 2009.10). It was found that waterflood after steam injection interruption achieved the highest net cumulative oil compared to other fluids injection. Moreover, it was observed that steam and alternative fluids, co-injected and alternately, did not present increase on profitability project compared with steamflooding / Muitas das reservas de hidrocarbonetos existentes em todo o mundo s?o formadas por ?leos pesados (?API entre 10 e 20). Al?m disso, v?rios campos de ?leo pesado est?o maduros e, portanto, oferecem grandes desafios para a ind?stria do petr?leo. Entre os m?todos t?rmicos utilizados para recuperar estes recursos, a inje??o de vapor tem sido a principal alternativa economicamente vi?vel. O calor latente transportado por meio de vapor aquece o reservat?rio, reduzindo a viscosidade do ?leo, facilitando a produ??o. A fim de aumentar a recupera??o de ?leo e reduzir os custos inerentes ? inje??o de vapor, a inje??o de fluidos alternativos tem sido utilizado em combina??o com o vapor das seguintes formas: alternadamente, coinjetados e ap?s a interrup??o da inje??o de vapor. O objetivo principal destes sistemas de inje??o combinada ? reduzir a quantidade de calor fornecida ao reservat?rio utilizando fluidos de menor valor comercial, buscando manter os n?veis de produ??o de ?leo. Este trabalho analisa o uso do di?xido de carbono, nitrog?nio, metano e ?gua como fluido alternativo ao vapor. Os par?metros analisados foram a recupera??o de ?leo e a produ??o acumulada l?quida. O modelo de reservat?rio analisado corresponde a um reservat?rio de dimens?es 100 m x 100 m x 28 m, num sistema de coordenadas cartesianas ( dire??es x, y e z). ? um modelo semissint?tico com alguns dados de reservat?rio semelhantes aos encontrados na Bacia Potiguar, Brasil. Todos os casos estudados foram simulados utilizando o simulador STARS da CMG (Computer Group, Modelagem vers?o 2009.10). Verificou-se que a inje??o de ?gua ap?s a interrup??o de inje??o de vapor alcan?ou melhores resultados em termos de produ??o acumulada l?quida de ?leo em rela??o a inje??o de outros fluidos. Al?m disso, foi observado que o vapor e os fluidos alternativos, coinjetados e alternados, n?o apresentou aumento na rentabilidade do projeto em compara??o com a inje??o cont?nua de vapor

Orientador: Maria Cristina Dias Tavares / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-25T04:21:56Z (GMT). No. of bitstreams: 1 Magrin_FabianoGustavoSilveira_M.pdf: 5471875 bytes, checksum: 204630879d78c9f5167f324d6d0f5fe9 (MD5) Previous issue date: 2014 / Resumo: Devido à dificuldade de execução de testes em sistemas reais os engenheiros procuram ferramentas e modelos para simular ou emular os sistemas reais em laboratório. Nesse sentido, o objetivo deste projeto de pesquisa foi desenvolver um modelo do relé de proteção diferencial de transformador no simulador digital em tempo real RTDS, baseando-se no relé SEL-787 da Schweitzer Engineering Laboratories Inc. O objetivo de criar um relé específico e já existente no mercado, saindo dos modelos genéricos, é devido à necessidade dos estudos em laboratório apresentarem resultados concretos e que representem o sistema real, desta forma apresentará grande valia para as futuras expansões do Sistema Elétrico Nacional ou Internacional. Após o desenvolvimento do modelo matemático do relé, foram criadas rotinas de teste exclusivas para análise do modelo e este foi testado em conjunto com um relé SEL-787 de forma a permitir uma comparação dos resultados. Para a realização deste trabalho foram estudadas e analisadas as situações em que um relé de proteção diferencial de transformador enfrenta no campo, como energização de transformador, saturação, faltas externas, faltas externas com saturação de TC, faltas internas a seção diferencial e externa ao transformador e faltas internas ao transformador como falta espira-terra e entre espiras. Os mesmos testes foram aplicados ao modelo de relé diferencial já existente na biblioteca do RTDS com o intuito de verificar se realmente modelos genéricos apresentam resultados diferentes de modelos específicos. A contribuição da pesquisa foi o desenvolvimento pioneiro do modelo do relé de proteção diferencial no ambiente RTDS / Abstract: Due to the difficulties involving tests in real systems engineers continuously look for tools and models to simulate or emulate real systems inside laboratories. With this focus, this job had the objective of developing a transformer differential protection relay in Real Time Digital Simulator, RTDS, based on SEL-787 relay, manufactured by Schweitzer Engineering Laboratories Inc. The objective of creating a specific relay already in the market, and not a generic model relay, is due to the necessity of the laboratories studies give real results and also represent the real system. This actual representation gives the engineers a more concrete data to support future expansions of the national and international electric systems. After the development of the relay model itself, it was tested in conjunction with a real SEL-787 allowing comparison of the results. For the accomplishment of this job many different situations which interfere in the daily operation of the relay in the field such as inrush, saturation, external faults, external faults with current transformer saturation, internal fault to the differential section but external to the transformer and internal faults like turn-to-turn faults and ground faults were studied and analyzed. The same tests were applied to a differential relay model already in the RTDS library with the purpose to verify whether generic models have different results compared to specific models. This research formerly presents a transformer differential relay model of a commercial relay for RTDS library / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

Orientador: João Maurício Rosário, Didier Dumur / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia / Made available in DSpace on 2018-08-20T08:06:43Z (GMT). No. of bitstreams: 1 LaraMolina_FabianAndres_D.pdf: 6567422 bytes, checksum: 5d5531b99af8de161a3f8f390bcac8cf (MD5) Previous issue date: 2012 / Resumo: Este trabalho visa o desenvolvimento, síntese e aplicação de um controlador baseado em controle preditivo generalizado para rastreamento de trajetórias de robôs paralelos. A finalidade é melhorar o desempenho dinâmico do robô paralelo através do desenvolvimento de controladores avançados que considerem características do robô tais como não-linearidades da dinâmica, incertezas paramétricas e distúrbios externos. Inicialmente é revisada a formulação do modelo dinâmico do robô paralelo que envolve: modelo geométrico, cinemático e dinâmico. À continuação é realizado o projeto dos controladores de posição no espaço das juntas: controladores de torque computado com PID na forma RST, controlador preditivo generalizado e robustificação com os parâmetros de Youla. A seguir, a dinâmica do robô paralelo e os controladores desenvolvidos são simulados no ambiente MATLAB/Simulink. Finalmente, é realizada a implementação experimental e validação dos controladores no robô Orthoglide no laboratório de robótica do IRCCyN, École Centrale de Nantes. O controlador preditivo generalizado robustificado melhora a resposta dinâmica em relação ao controlador de torque computado que tem sido amplamente utilizado nesta classe de robôs. Os resultados obtidos através da implementação experimental da lei de controle preditiva robustificada no robô Orthoglide e testes experimentais indicam que o desempenho dinâmico do robô é melhorado em termos das seguintes caraterísticas: precisão no rastreamento de trajetórias típicas para usinagem no espaço de trabalho, estas trajetórias são executadas com diferentes acelerações máximas; robustez a variação dos parâmetros do robô tais como mudança da carga na plataforma móvel, obtendo desta forma uma melhor regulação; e finalmente, atenuação do efeito do ruído de medição nos sensores no sinal de controle dos atuadores durante a execução de um movimento. Os resultados experimentais mostraram que o controlador preditivo generalizado robustificado aplicado no robô Orthoglide é eficiente frente as incertezas paramétricas e restrições no domínio do tempo, melhorando assim o desempenho dinâmico do robô com um custo computacional equivalente ao controle de torque computado / Abstract: This thesis addresses the development and application of a controller based on generalized predictive control to track a desired trajectory using parallel robots. The main purpose of this thesis is to improve the dynamical behavior with an advanced controller which considers the proper characteristics of the parallel robot such as no linear dynamics, parameters uncertainties and external disturbances. This work is divided into four parts. A first part formulates the complete dynamical model of the parallel robot, considering the geometrical, kinematic and dynamic modelling. Then, the joint space control is performed for the parallel robot using the computed torque controller in the RST form and the robustified generalized predictive control via Youla parameterization. A third part shows the simulation of the dynamic of the robot with the controllers in MATLAB/Simulink to establish a comparison between controllers. Finally, the controllers are implemented in the prototype and some experiments are performed on the Orthoglide robot at the laboratory of robotics, IRCCyN, Ecole Centrale de Nantes to assess the dynamic performance of the controllers. The experimental results show that the robustification of the generalized predictive control against parametric uncertainties including time domain constraints improves the dynamical behavior of the parallel robots. The experimental results shows that the the robustified generalized predictive control enhances the dynamic performance of is in terms of: tracking accuracy of trajectories used in milling process; robustness to parameters variation such as payload changing (on the end effector), therefore, a better regulation is obtained; and finally, attenuation of noise due to sensor measurement in control. Additionally, the robustification of the generalized predictive control applied on the Orthoglide robot improves the dynamical behavior compared to controllers widely used in parallel robots such as computed torque control with and equivalent computational cost / Doutorado / Mecanica dos Sólidos e Projeto Mecanico / Doutor em Engenharia Mecânica

Abstract Most of the current building simulation tools are the results of funded projects for particular research purposes. Normally, these tools are developed in one research organization and utilized by the organization's own staff rather than by external personnel. Financially and intellectually, it is definitely a huge waste that designers and engineers rarely use those tools while they have to deal with increasingly complex issues and surely need the assistance of building simulation tools in building practice. Therefore, this thesis is dedicated to bringing building simulation closer to practice. The general goal is to promote the usage of simulation tools not only by simulation experts for research purposes but also by designers and engineers in practical work. Abstract Since the well-adopted tool could only be established based on appropriate requirements analysis, attention is firstly devoted to perceiving engineer or practice demands in building design and operation activities. Building multi-criteria analysis, whole life cycle integration, interdisciplinary interaction, control-wise integration/optimization together with the influence of “Industry 4.0” in building discipline are discussed in sequence. This is not only an enumeration of emerging scenarios, but also an exploration to figure out that integrated requirement is of growing significance as buildings are becoming increasingly advanced and complex. Abstract Multi-criteria simulation analysis indicates that designers and engineers need to consider, at least, energy efficiency and initial cost simultaneously; human comfort, environmental impact, life cycle cost are also involved; however, current workflow and cooperation mechanism among different simulation tools could not sufficiently fulfill multi-criteria analysis demand in building design and operation activities. Other detailed discussions on energy and cost integrated simulation, energy and human comfort integrated simulation, control related simulations all indicate one conclusion that building practice is increasingly integrated but simulation ability is still insufficient and isolated. Therefore, related tools must be coordinated and connected from the socio-technical point of view to support building practice eventually. Abstract Recent development in multi-domain modeling language Modelica and Functional Mock-up Interface (FMI) standard has provided an efficient solution for both integration and practical utilization. The ideology of the transfer layer is introduced; open-to-public and free usable framework and associated collaborative mechanisms are proposed. Individual models and tools could be integrated together through co-simulation or model exchange under FMI standard; along with complete and accurate database, the integrated tools could be validated and documented together, then transferred to commercial partners for further improvement, marketing and sale. In such way, a collaborative framework to transfer knowledge from research to practice could be formed in order to sufficiently process integrated requirement issues; the usage of research-oriented tools could be intensified in building industrial practice. Abstract Connection, interoperability, technical standard, and workflow protocol, those general terms for cooperative simulation development are further discussed. Cooperative Modelica library development is taken as an example to illustrate associated problems and their solutions from both detailed technical and generalized socio-technical perspectives. Abstract Individual model quality is a fundamental guarantee for successful cooperative simulation system. Therefore a model comparison project is carried out for quality assurance purpose. First, a series of comparison validation tests are established with a stepwise increased level of complexity. Then, multiple participants with a diversity of simulation tools contribute simulation models and results for listed validation scenarios. During the result comparison process, the deviation is detected, the bug is fixed, the model is improved; cooperative relationship and workflow standard are formed. Abstract In the last, a multi-criteria and interdisciplinary simulation case is conducted as a demonstrated example of actual integrated requirement along with integration and practical utilization effort of simulation. This case aims to select an appropriate energy solution for a building from four alternatives. Traditional HVAC equipment, renewable energy devices, storage facilities are applied and arranged in groups under Demand Side Management strategy and dynamic control. Financial and environmental impacts are also calculated along with the traditional result of annual energy consumption. Multiple Criteria Decision Analysis (MCDA) method is applied to analyze the four alternative energy solutions with an overall consideration of energy consumption, energy production, initial cost, life-cycle cost, and CO2 emission.:Chapter 1 Introduction Chapter 2 Integrated requirements in building practice Chapter 3 Isolated and insufficient building simulation tools Chapter 4 Practice oriented tool integration and improvement Chapter 5 Cooperative development in Modelica and Annex 60 Chapter 6 Model comparison cooperation Chapter 7 Conclusion and future work

<p>Recent developments in semiconductor device technology have seen the advent of wide-bandgap (WBG) based devices that enable operation at high switching frequencies. These devices, such as silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs), are becoming a favored choice in inverters for electric drive systems because of their lower switching losses and higher allowable operating temperature. However, the fast switching of such devices implies increased voltage edge rates (high <i>dv/dt</i>) that give rise to various undesirable effects including large common-mode currents, electromagnetic interference, transient overvoltages, insulation failure due to the overvoltages, and bearing failures due to</p> <p>microarcs. With increased use of these devices in transportation and industrial applications, it is imperative that accurate models and efficient simulation tools, which can predict these high-frequency effects and accompanying system losses, be established. This research initially focuses on establishing an accurate wideband model of a surface-mount permanent-magnet</p> <p>ac machine supplied by a WBG-based inverter. A new multirate simulation framework for predicting the transient behavior and estimating the power losses is then set forth. In this approach,</p> <p>the wideband model is separated into high- and low-frequency models implemented using two different computer programs that are best suited for the respective time scales. Repetitive execution of the high-frequency model yields look-up tables for the switching losses in the semiconductors, electric machine, and interconnecting cable. These look-up tables are then incorporated into the low-frequency model that establishes the conduction</p> <p>losses. This method is applied to a WBG-based electric drive comprised of a SiC inverter and permanent-magnet ac machine. Comparisons of measured and simulated transients are provided.</p>