Controle on-line do número de não-conformidades por itens em uma produção finita

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Análise e síntese de antenas e superfícies seletivas de frequência utilizando computação evolucionária e inteligência de enxames

The frequency selective surfaces, or FSS (Frequency Selective Surfaces), are structures consisting of periodic arrays of conductive elements, called patches, which are usually very thin and they are printed on dielectric layers, or by openings perforated on very thin metallic surfaces, for applications in bands of microwave and millimeter waves. These structures are often used in aircraft, missiles, satellites, radomes, antennae reflector, high gain antennas and microwave ovens, for example. The use of these structures has as main objective filter frequency bands that can be broadcast or rejection, depending on the specificity of the required application. In turn, the modern communication systems such as GSM (Global System for Mobile Communications), RFID (Radio Frequency Identification), Bluetooth, Wi-Fi and WiMAX, whose services are highly demanded by society, have required the development of antennas having, as its main features, and low cost profile, and reduced dimensions and weight. In this context, the microstrip antenna is presented as an excellent choice for communications systems today, because (in addition to meeting the requirements mentioned intrinsically) planar structures are easy to manufacture and integration with other components in microwave circuits. Consequently, the analysis and synthesis of these devices mainly, due to the high possibility of shapes, size and frequency of its elements has been carried out by full-wave models, such as the finite element method, the method of moments and finite difference time domain. However, these methods require an accurate despite great computational effort. In this context, computational intelligence (CI) has been used successfully in the design and optimization of microwave planar structures, as an auxiliary tool and very appropriate, given the complexity of the geometry of the antennas and the FSS considered. The computational intelligence is inspired by natural phenomena such as learning, perception and decision, using techniques such as artificial neural networks, fuzzy logic, fractal geometry and evolutionary computation. This work makes a study of application of computational intelligence using meta-heuristics such as genetic algorithms and swarm intelligence optimization of antennas and frequency selective surfaces. Genetic algorithms are computational search methods based on the theory of natural selection proposed by Darwin and genetics used to solve complex problems, eg, problems where the search space grows with the size of the problem. The particle swarm optimization characteristics including the use of intelligence collectively being applied to optimization problems in many areas of research. The main objective of this work is the use of computational intelligence, the analysis and synthesis of antennas and FSS. We considered the structures of a microstrip planar monopole, ring type, and a cross-dipole FSS. We developed algorithms and optimization results obtained for optimized geometries of antennas and FSS considered. To validate results were designed, constructed and measured several prototypes. The measured results showed excellent agreement with the simulated. Moreover, the results obtained in this study were compared to those simulated using a commercial software has been also observed an excellent agreement. Specifically, the efficiency of techniques used were CI evidenced by simulated and measured, aiming at optimizing the bandwidth of an antenna for wideband operation or UWB (Ultra Wideband), using a genetic algorithm and optimizing the bandwidth, by specifying the length of the air gap between two frequency selective surfaces, using an optimization algorithm particle swarm

Uma implementação paralela híbrida para o problema do caixeiro viajante usando algoritmos genéticos, GRASP e aprendizagem por reforço

The metaheuristics techiniques are known to solve optimization problems classified as NP-complete and are successful in obtaining good quality solutions. They use non-deterministic approaches to generate solutions that are close to the optimal, without the guarantee of finding the global optimum. Motivated by the difficulties in the resolution of these problems, this work proposes the development of parallel hybrid methods using the reinforcement learning, the metaheuristics GRASP and Genetic Algorithms. With the use of these techniques, we aim to contribute to improved efficiency in obtaining efficient solutions. In this case, instead of using the Q-learning algorithm by reinforcement learning, just as a technique for generating the initial solutions of metaheuristics, we use it in a cooperative and competitive approach with the Genetic Algorithm and GRASP, in an parallel implementation. In this context, was possible to verify that the implementations in this study showed satisfactory results, in both strategies, that is, in cooperation and competition between them and the cooperation and competition between groups. In some instances were found the global optimum, in others theses implementations reach close to it. In this sense was an analyze of the performance for this proposed approach was done and it shows a good performance on the requeriments that prove the efficiency and speedup (gain in speed with the parallel processing) of the implementations performed

Estudo de Superfícies Seletivas de Frequência com o Uso de Inteligência Computacional

The main objective of this work is to optimize the performance of frequency selective surfaces (FSS) composed of crossed dipole conducting patches. The optimization process is performed by determining proper values for the width of the crossed dipoles and for the FSS array periodicity, while the length of the crossed dipoles is kept constant. Particularly, the objective is to determine values that provide wide bandwidth using a search algorithm with representation in bioinspired real numbers. Typically FSS structures composed of patch elements are used for band rejection filtering applications. The FSS structures primarily act like filters depending on the type of element chosen. The region of the electromagnetic spectrum chosen for this study is the one that goes from 7 GHz to 12 GHz, which includes mostly the X-band. This frequency band was chosen to allow the use of two X-band horn antennas, in the FSS measurement setup. The design of the FSS using the developed genetic algorithm allowed increasing the structure bandwidth

Comportamento social de botos-cinza, sotalia guianensis, na praia de Pipa, RN, Brasil: dinâmica, sequência, sincronia e respostas ao turismo de observação

Social behavior of Guiana dolphins, Sotalia guianensis, at Pipa Beach, RN, Brazil: dynamics, sequence, breathing synchrony, and responses to dolphin watching. Social animals form groups that can range from temporary to permanent. Depending on the nature of the social relationships developed between individuals, groups present a particular social organization and the effect of these interactions shapes the activity patterns of these animals. This study investigates: (i) fission-fusion dynamics of Guiana dolphins, through the analysis of three dimensions of the social system (variation in spatial cohesion, variation in size and composition of groups), (ii) sequence, routine and behavioral stability, (iii) breathing intervals in synchronized groups and (iv) behavioral responses of the animals to dolphin watching. Systematic observations of Guiana dolphins were made from a platform located in cliffs about 25 m above sea level that surround Madeiro Bay, Pipa Beach. Sampling occurred from December 2007 to February 2009 between 0600 h and 1600 h, and the groups of Guiana dolphins were investigated according to their size (alone and group) and composition (adults, adults and juveniles, and adults and calves). According to the analysis of fission-fusion dynamics, Guiana dolphin groups frequently changed their composition, modifying their patterns of spatial grouping and cohesion every 20 minutes on average. More than 50% of the individuals maintained a distance of up to 2 m from other group members and new individuals were attracted to the group, especially during feeding, leaving it for foraging. Large groups were more unstable than small, while groups containing only adults were more stable than groups of adults and juveniles. According to the Z-score analysis to investigate the sequence and behavioral routine, lone individuals were more ! .7! ! involved in foraging and feeding, while resting was more common in groups. Foraging and feeding were more common in homogeneous groups (individuals of the same age class), while heterogeneous groups (different age classes) were often involved in socialization, displaying a broader behavioral repertoire. Foraging and resting behavior presented higher stability (continuous duration in minutes) than the other behaviors. The analysis of breathing intervals in synchronized groups showed significant differences depending on type of behavior, composition and area preference. During resting, breathing intervals were of longer duration, and groups with calves showed shorter breathing intervals than groups without calves. Lone individuals also preferred areas called corral , often used for the entrapment of fishes. The Markov chain analysis revealed behavioral changes in the presence of boats, according to the type of group composition. Groups composed of adults presented decreased resting and increased in traveling during the presence of boats. Groups of adults and juveniles showed a massive reduction of socialization, while the behavior transition probability traveling-traveling was higher in groups of adults and calves. In the presence of the boats, stability of resting was reduced by one third of its original duration and traveling more than doubled. The behavioral patterns analyzed are discussed in light of socio-ecological models concerning costs and benefits of proximity between individuals and behavioral optimization. Furthermore, significant changes in behavioral patterns indicate that Guiana dolphins, at Pipa Beach, have suffered the effects of tourism as a result of violation of rules of conduct established for the study area

Modelo de programação matemática para controle do crescimento da vegetação sob redes de distribuição de energia elétrica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Métodos estatisticos em cadeias de Markov

Este trabalho tem como objetivo o estudo do comportamento assintótico da estatística de Pearson (1900), que é o aparato teórico do conhecido teste qui-quadrado ou teste x2 como também é usualmente denotado. Inicialmente estudamos o comportamento da distribuição da estatística qui-quadrado de Pearson (1900) numa amostra {X1, X2,...,Xn} quando n → ∞ e pi = pi0 , 8n. Em seguida detalhamos os argumentos usados em Billingley (1960), os quais demonstram a convergência em distribuição de uma estatística, semelhante a de Pearson, baseada em uma amostra de uma cadeia de Markov, estacionária, ergódica e com espaço de estados finitos S

Teoria da Ruína em um Modelo de Markov com dois Estados

In this work, we present a risk theory application in the following scenario: In each period of time we have a change in the capital of the ensurance company and the outcome of a two-state Markov chain stabilishs if the company pays a benece it heat to one of its policyholders or it receives a Hightimes c > 0 paid by someone buying a new policy. At the end we will determine once again by the recursive equation for expectation the time ruin for this company

Comparação de diferentes estratégias para a análise de características de crescimento e de carcaça de suínos cruzados: modelos finito e infinitesimal poligênico

Foi utilizada uma análise de segregação com o uso da inferência Bayesiana para estimar componentes de variância e verificar a presença de genes de efeito principal (GEP) influenciando duas características de carcaça: gordura intramuscular (GIM), em %, e espessura de toucinho (ET), em mm; e uma de crescimento, ganho de peso (g/dia) dos 25 aos 90 kg de peso vivo (GP). Para este estudo, foram utilizadas informações de 1.257 animais provenientes de um delineamento de F2, obtidos do cruzamento de suínos machos Meishan e fêmeas Large White e Landrace. No melhoramento genético animal, os modelos poligênicos finitos (MPF) podem ser uma alternativa aos modelos poligênicos infinitesimais (MPI) para avaliação genética de características quantitativas usando pedigrees complexos. MPI, MPF e MPI combinado com MPF foram empiricamente testados para se estimar componentes de variâncias e número de genes no MPF. Para a estimação de médias marginais a posteriori de componentes de variância e de parâmetros, foi utilizada uma metodologia Bayesiana, por meio do uso da Cadeia de Markov, algoritmos de Monte Carlo (MCMC), via Amostrador de Gibbs e Reversible Jump Sampler (Metropolis-Hastings). em função dos resultados obtidos, pode-se evidenciar quatro GEP, sendo dois para GIM e dois para ET. Para ET, o GEP explicou a maior parte da variação genética, enquanto, para GIM, o GEP reduziu significativamente a variação poligênica. Para a variação do GP, não foi possível determinar a influência do GEP. As herdabilidades estimadas ajustando-se MPI para GIM, ET e GP foram de 0,37; 0,24 e 0,37, respectivamente. Estudos futuros com base neste experimento que usem marcadores moleculares para mapear os genes de efeito principal que afetem, principalmente GIM e ET, poderão lograr êxito.

Alocação otimizada de bancos de capacitores em sistemas de distribuição de energia elétrica através de metaheurísticas multiobjetivo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Treinamento de uma rede neural de base radial usando computação evolutiva: implementação e aplicações

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uma ferramenta alternativa para síntese de circuitos lógicos usando a técnica de circuito evolutivo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Métodos metaheurísticos aplicados a um modelo de planejamento de culturas

Pós-graduação em Biometria - IBB

Planejamento econômico de gráficos de controle X para monitoramento de processos autocorrelacionados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)