DECOM - Trabalhos apresentados em eventos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/581
Navegar
8 resultados
Resultados da Pesquisa
Item Sistemas do tipo eixo-raio aplicados a redes de sensores sem fio mdeladas cmo Redes Small World.(2007) Guidoni, Daniel Ludovico; Aquino, André Luiz Lins de; Cabral, Raquel da Silva; Loureiro, Antônio Alfredo Ferreira; Fernandes, Antônio OtávioAs redes de sensores sem fio possuem restrições de recursos, tais como baixo poder computacional, largura de banda reduzida e especialmente, fonte de energia limitada. O alto consumo de energia pode ser observado quando o fluxo de dados em cada n´o ´e alto e quando o numero de vizinhos e grande. Alem disso, essas redes podem ser modeladas como redes do tipos small world, onde o coeficiente de agrupamento é alto e o caminho médio mínimo entre cada par de nos na rede é pequeno. Através da utilização do conceito de sistemas do tipo eixo-raio, obtivemos uma configuração com um caminho médio mínimo pequeno entre qualquer par de n´os, obtendo assim, uma configuração ótima para a rede, onde alguns n´os são escolhidos como concentradores garantindo o menor consumo de energiaItem Um esquema de gerenciamento para redes de sensores sem fio auto-organizáveis : atuando sobre regras locais.(2007) Figueiredo, Carlos Maurício Seródio; Aquino, André Luiz Lins de; Loureiro, Antônio Alfredo Ferreira; Ruiz, Linnyer BeatrysAuto organização e um importante conceito sendo aplicado em sistemas de rede modernos para obter funcionamento autônomo e robusto. Particularmente, as Redes de Sensores Sem Fio (RSSFs) foram concebidas sob esse paradigma. Basicamente, em uma rede auto organizável, os elementos interagem somente entre si, de forma completamente descentralizada, para executar uma função para o correto funcionamento da rede. No entanto, os objetivos determinados por uma entidade de gerência ou aplicação podem mudar ao longo do tempo, e um esquema para controlar as interações entre os elementos e ajustar ou mudar o comportamento global a ser obtido a um novo requisito n ˜ao foi explicitamente abordado na literatura. Neste trabalho, é apresentado um esquema geral para o gerenciamento de redes auto organizáveis. Sua ideia geral consiste em atuar sobre as regras de interação locais governando as interações entre os elementos e, consequentemente, adequando o comportamento da rede a diferentes objetivos e/ou métricas de QoS necessárias. Uma metodologia também é provida, e essa define um procedimento genérico e relaciona importantes aspectos para o projeto de soluções de gerenciamento. A aplicabilidade do esquema proposto é demonstrada através da apresentação de um estudo de caso.Item On the use data reduction algorithms for real-time Wireless Sensor Networks.(2007) Aquino, André Luiz Lins de; Figueiredo, Carlos Maurício Seródio; Nakamura, Eduardo Freire; Loureiro, Antônio Alfredo Ferreira; Fernandes, Antônio Otávio; Coelho Júnior, Claudionor José NunesThis work presents the design of real time applications for Wireless Sensor Networks (WSNs) by using analgorithm based on data stream to process the sensor data. The proposed algorithm is based on sampling techniques applied to data histograms created from original data stream sac quired by sensor nodes. As a result, the algorithm provides a sample of log n item store present the original data stream of n elements. In this work, we show how to use the data reduction algorithmin real-time WSN design.Item Data stream based algorithms for wireless sensor network applications(2007) Aquino, André Luiz Lins de; Figueiredo, Carlos Maurício Seródio; Nakamura, Eduardo Freire; Buriol, Luciana Salete; Loureiro, Antônio Alfredo Ferreira; Fernandes, Antônio Otávio; Coelho Júnior, Claudionor José NunesA wireless sensor network (WSN) is energy con-strained, and the extension of its lifetime is one of the most important issues in its design. Usually, a WSN collects a large amount of data from the environment. In contrast to the conventional remote sensing – based on satellites that collect large images, sound files, or specific scientific data – sensor networks tend to generate a large amount of sequential small and tuple-oriented data from several nodes, which constitutes data streams. In this work, we propose and evaluate two algorithms based on data stream, which use sampling and sketch techniques, to reduce data traffic in a WSN and, consequently, decrease the delay and energy consumption. Specifically, the sampling solution, provides a sample of only log n items to represent the original data of n elements. Despite of the reduction, the sampling solution keeps a good data quality. Simulation results reveal the efficiency of the proposed meth-ods by extending the network lifetime and reducing the delay without loosing data representativeness. Such a technique can be very useful to design energy-efficient and time-constrained sensor networks if the application is not so dependent on the data precision or the network operates in an exception situation (e.g., there are few resources remaining or there is an urgent situation)Item Redes de sensores sem fio para monitoramento de anfíbios.(2008) Aquino, André Luiz Lins de; Figueiredo, Carlos Maurício Seródio; Loureiro, Antônio Alfredo Ferreira; Mini, Raquel Aparecida de Freitas; Nakamura, Eduardo Freire; Oliveira, Horácio Antônio Braga Fernandes de; Ruiz, Linnyer BeatrysItem Analysis of selection and crossover methods used by genetic algorithm-based heuristic to solve the LSP allocation problem in MPLS Networks under capacity constraints(2008) Andrade, Alessandro Vivas; Errico, Luciano de; Aquino, André Luiz Lins de; Assis, Luciana Pereira de; Barbosa, Carlos Henrique Nogueira de ResendeThe Multiprotocol Label Switching (MPLS) is a popular routing technique for IP networks, where the core problem is to find a route (called LSP) that satisfy all the capacity constraints imposed by a specific traffic. Genetic algorithms come as a simple, appealing solution approach, but one that requires careful choices concerning initial population generation, crossover, mutation and selection. The present paper discusses the influence of different crossover and selection methods in achieving a fast and accurate convergence of the genetic algorithm, when solving the MPLS allocation problem. The experimental results, using different network topologies such as Carrier, Dora, and Mesh, have shown that uniform crossover and Stochastic Remainder Sampling selection are the most suitable combination to solve the problem.Item Evolutionary design of wireless sensor networks based on complex networks.(2009) Ruela, André Siqueira; Cabral, Raquel da Silva; Aquino, André Luiz Lins de; Guimarães, Frederico GadelhaThis work proposes a genetic algorithm for design-ing a wireless sensor network based on complex network theory. We develop an heuristic approach based on genetic algorithms for finding a network configuration such that its communication structure presents complex network characteristics, e.g. a small value for the average shortest path length and high cluster coefficient. The work begins with the mathematical model of the hub location problem, developed to determine the nodes which will be configured as hubs. This model was adopted within the genetic algorithm. The results reveal that our methodology allows the configuration of networks with more than a hundred nodes with complex network characteristics, thus reducing the energy consumption and the data transmission delay.Item Multivariate reduction in wireless sensor networks.(2009) Silva Junior, Orlando; Aquino, André Luiz Lins de; Mini, Raquel Aparecida de Freitas; Figueiredo, Carlos Maurício SeródioIn wireless sensor networks, energy consumption is generally associated with the amount of sent data once communication is the activity of the network that consumes more energy. This work proposes an algorithm based on "Principal Component Analysis "to perform multivariate data reduction. It is considered air quality monitoring scenario as case study. The results show that, using the proposed technique, we can reduce the data sent preserving its representativeness. Moreover, we show that the energy consumption and delay are reduced proportionally to the amount of reduced data