Esta dissertação apresenta uma arquitetura de controle distribuída para um sistema de visão computacional propositada, modelada segundo uma abordagem de Inteligência Artificial Distribuída com ênfase em Sistemas Multi-Agentes. O principal problema abordado é o da integração de diversos módulos com tarefas e comportamentos diferentes em um sistema robótico, que utiliza visão computacional para perceber o mundo. Esta integração surge da organização de diversas soluções dedicadas a diferentes tarefas visuais, resultando na proposta de uma arquitetura constituída por uma sociedade de Agentes Autônomos (AAs), que comunicam entre si através de uma rede de comunicação descentralizada e totalmente conectada, sendo cada AA responsável por um comportamento independente, organizados segundo regras de comportamento e uma estrutura de autoridade. Essa arquitetura integra diversos módulos da cognição, como percepção visual, planejamento, controle e atuação. Como tentativa de validação experimental da proposta, essa arquitetura foi implementada em um sistema dotado de um manipulador robótico e uma câmera, trabalhando em um domínio de montagem. A estrutura básica da arquitetura foi desenvolvida segundo uma metodologia de projeto orientada a objetos e consiste em uma biblioteca de classes que definem o modelo dos agentes e as estruturas para as interações entre esses em uma sociedade. O sistema robótico proposto foi implementado na Célula Flexível de Montagem da Escola Politécnica da USP, tendo por objetivo realizar tarefas de montagens simples e visualmente guiadas. O sistema foi testado exaustivamente e os resultados experimentais indicaram algumas vantagens e desvantagens da metodologia empregada, possibilitando a definição de algumas diretrizes importantes para o projeto e implementação de sistemas robóticos inteligentes atuando no mundo real. / This dissertation presents a distributed control architecture for a purposive computer vision system, modeled according to a Distributed Artificial Intelligence approach, with emphasis in Multi-Agents Systems. The main problem addressed is the integration of several modules with different purposes and behaviors in a robotic system, which uses computer vision to perceive the world. This integration arises from the organization of several dedicated solutions to different visual tasks, resulting in the proposal of one architecture that consists of a society of Autonomous Agents, communicating with each other through a decentralized and fully connected network, where each AA is responsible for an independent behavior. This society is organized according to behavior rules and an authority structure. Furthermore, this architecture integrates several cognitive modules, like visual perception, planning, control and action. As an attempt of an experimental validation of the proposal, this architecture was implemented in a system composed of a robotic manipulator and one camera, working in an assembly domain. The basic structure of the architecture was developed according to an object oriented methodology and consists of a library of classes which defines the agents\' model and the structures needed for the interactions among these agents in a society. The proposed robotic system was implemented in the Flexible Assembly Cell of the Escola Politécnica da USP, with the objective of accomplishing simple and visually guided assembly tasks. The system was thoroughly tested and the experimental results indicated some advantages and inconveniences of the methodology, allowing the definition of some important guidelines for the design and implementation of intelligent robotic systems acting in the real world.

Esta dissertação apresenta uma arquitetura de controle distribuída para um sistema de visão computacional propositada, modelada segundo uma abordagem de Inteligência Artificial Distribuída com ênfase em Sistemas Multi-Agentes. O principal problema abordado é o da integração de diversos módulos com tarefas e comportamentos diferentes em um sistema robótico, que utiliza visão computacional para perceber o mundo. Esta integração surge da organização de diversas soluções dedicadas a diferentes tarefas visuais, resultando na proposta de uma arquitetura constituída por uma sociedade de Agentes Autônomos (AAs), que comunicam entre si através de uma rede de comunicação descentralizada e totalmente conectada, sendo cada AA responsável por um comportamento independente, organizados segundo regras de comportamento e uma estrutura de autoridade. Essa arquitetura integra diversos módulos da cognição, como percepção visual, planejamento, controle e atuação. Como tentativa de validação experimental da proposta, essa arquitetura foi implementada em um sistema dotado de um manipulador robótico e uma câmera, trabalhando em um domínio de montagem. A estrutura básica da arquitetura foi desenvolvida segundo uma metodologia de projeto orientada a objetos e consiste em uma biblioteca de classes que definem o modelo dos agentes e as estruturas para as interações entre esses em uma sociedade. O sistema robótico proposto foi implementado na Célula Flexível de Montagem da Escola Politécnica da USP, tendo por objetivo realizar tarefas de montagens simples e visualmente guiadas. O sistema foi testado exaustivamente e os resultados experimentais indicaram algumas vantagens e desvantagens da metodologia empregada, possibilitando a definição de algumas diretrizes importantes para o projeto e implementação de sistemas robóticos inteligentes atuando no mundo real. / This dissertation presents a distributed control architecture for a purposive computer vision system, modeled according to a Distributed Artificial Intelligence approach, with emphasis in Multi-Agents Systems. The main problem addressed is the integration of several modules with different purposes and behaviors in a robotic system, which uses computer vision to perceive the world. This integration arises from the organization of several dedicated solutions to different visual tasks, resulting in the proposal of one architecture that consists of a society of Autonomous Agents, communicating with each other through a decentralized and fully connected network, where each AA is responsible for an independent behavior. This society is organized according to behavior rules and an authority structure. Furthermore, this architecture integrates several cognitive modules, like visual perception, planning, control and action. As an attempt of an experimental validation of the proposal, this architecture was implemented in a system composed of a robotic manipulator and one camera, working in an assembly domain. The basic structure of the architecture was developed according to an object oriented methodology and consists of a library of classes which defines the agents\' model and the structures needed for the interactions among these agents in a society. The proposed robotic system was implemented in the Flexible Assembly Cell of the Escola Politécnica da USP, with the objective of accomplishing simple and visually guided assembly tasks. The system was thoroughly tested and the experimental results indicated some advantages and inconveniences of the methodology, allowing the definition of some important guidelines for the design and implementation of intelligent robotic systems acting in the real world.

A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the degree of Master of Science / The aim of this work was to evaluate the measurement of the optical properties as a means of obtaining information on the growth history of synthetic diamond. A suite of sample of known synthesis origin representing the different types of commercially produced synthetic diamond was analysed hy photoluminescence. The photoh.{fnmescence intensity was normalising by using the area of tbe Raman peak. This allowed a semi-quantitative comparison of the defect concentration. Three photoluminescent centres were identified, H3, 575 run and 1.945 eV (with zero-phonon lines at 2.463 eV, 2.156 eV, and 1.945 eV respectively). Differences between the intensities of the luminescence due to these centres were observed as a function of the type ot diamond The H3 amd the 1.945 eV intensity was found to increase with the proportion of cubic growth sector, In addition the 1.945 eV intensity was found to increase with heat treatment and was higher in (100) than in (111) growth sectors. As all three defects detected involve vacancies and nitrogen impurity, an analysis was done to quantify any correlation between the luminescent intensities from the different defects in the same SDA powder sample. The 1.945 eV and 575 run intensities were observed to be correlated .. An additional correlation 'was found between the 575 lim and the H3 intensities in the case of finer particle size samples. The luminescence intensity for all three defect types was observed to be a function of the particle size of the sample. The shapes and widths of zero-phonon lines were related to the types and concentration of lattice defects present in a crystal according to line broadening theory. An attempt was made to explain the results in the context of the known synthesis origin and growth conditions. / AC 2018

Não disponibilizado pelo autor. / Not available.

Currently available wind-wave prediction models require a prohibitive amount of computing time for simulating non-linear wave-wave interactions. Moreover, some parts of wind-wave generation processes are not fully understood yet. For this reason accurate predictions are not always guaranteed. In contrast, Artificial Neural Network (ANN) techniques are designed to recognize the patterns between input and output so that they can save considerable computing time so that real-time wind-wave forecast can be available to the navy and commercial ships. For this reason, this study tries to use ANN techniques to predict waves for winter storms and hurricanes with much less computing time at the five National Oceanic and Atmospheric Administration (NOAA) wave stations along the East Coast of the U.S. from Florida to Maine (station 44007, 44013, 44025, 44009, and 41009). In order to identify prediction error sources of an ANN model, the 100% known wind-wave events simulated from the SMB model were used. The ANN predicted even untrained wind-wave events accurately, and this implied that it could be used for winter-storm and hurricane wave predictions. For the prediction of winter-storm waves, 1999 and 2001 winter-storm events with 403 data points had 1998 winter-storm events with 78 points were prepared for training and validation data sets, respectively. In general, because winter-storms are relatively evenly distributed over a large area and move slowly, wind information (u and v wind components) over a large domain was considered as ANN inputs. When using a 24-hour time-delay to simulate the time required for waves to be fully developed seas, the ANN predicted wave heights (r = 0.88) accurately, but the prediction accuracy of zero-crossing wave periods was much less (r = 0.61). For the prediction of hurricane waves, 15 hurricanes from 1995 to 2001 and Hurricane Bertha in 1998 were prepared for training and validation data sets, respectively. Because hurricanes affect a relatively small domain, move quickly, and change dramatically with time, the location of hurricane centers, the maximum wind speed, central pressure of hurricane centers, longitudinal and latitudinal distance between wave stations and hurricane centers were used as inputs. The ANN predicted wave height accurately when a 24-hour time-delay was used (r = 0.82), but the prediction accuracy of peak-wave periods was much less (r = 0.50). This is because the physical processes of wave periods are more complicated than those of wave heights. This study shows a possibility of an ANN technique as the winter-storm and hurricane-wave prediction model. If more winter-storm and hurricane data can be available, and the prediction of hurricane tracks is possible, we can forecast real-time wind-waves more accurately with less computing time.

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 2012

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2010

Tese de mestrado. Inteligência Artificial e Computação. Faculdade de Ciências. Universidade do Porto. 2004

Tese de mestrado. Inteligência Artificial e Sistemas Inteligentes. 2006. Faculdade de Engenharia. Universidade do Porto

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Energia). Faculdade de Engenharia. Universidade do Porto. 2010