DECOM - Trabalhos apresentados em eventos

URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/581

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ABCTool - uma ferramenta para cooperação baseada na arquitetura do sistema.
(2002) Barros, Cynthia Maria Silva de; Pietrobon, Carlos Alberto Marques
O projeto de um sistema de software pode se tornar um trabalho bastante complexo em se tratando da construção de grandes sistemas. Assim, cada vez mais os projetistas têm reconhecido a importância do design da arquitetura no projeto do sistema com o propósito de facilitar o trabalho de desenvolvimento. Outro aspecto que também tem sido observado é o fato de que estes sistemas são desenvolvidos por grupos de pessoas que trabalham paralelamente e cooperativamente. A dificuldade de comunicação entre a equipe gera problemas na hora da integração das partes que cada um desenvolveu. Esse artigo propõe uma ferramenta de apoio ao desenvolvimento cooperativo de software baseado na arquitetura do sistema sendo desenvolvido.
Abordagem heurística para resolução do problema de programação mensal de tripulações de ônibus urbano.
(2005) Toffolo, Túlio Ângelo Machado; Souza, Marcone Jamilson Freitas; Silva, Gustavo Peixoto
Um algoritmo coevolutivo cooperativo para configuração de uma rede de sensores sem fio.
(2011) Ruela, André Siqueira; Aquino, André Luiz Lins de; Guimarães, Frederico Gadelha; Freitas, Alan Robert Resende de
This work proposes a cooperative coevolutionary algorithm for design of a wireless sensor network considering complex network metrics. It is proposed a heuristic to ﬁnd a network conﬁguration such that its communication structure presents a small value for the average shortest path length and a high cluster coefﬁcient. This conﬁguration considers a cluster based network, where the cluster heads have two communication radii. We describe how the problem can be partitioned and how the ﬁtness computation can be divided such that the cooperative coevolution model is feasible. The results reveal that our methodology allows the conﬁguration of networks with more than a hundred nodes with two speciﬁcs complex network measurements allowing the reduction of energy consumption and the data transmission delay.
Um algoritmo de amostragem multivariada para redes de sensores sem fio.
(2010) Silva Junior, Orlando; Aquino, André Luiz Lins de; Mini, Raquel Aparecida de Freitas
A wireless sensor network (WSN) is energy constrained, and the ex-tension of its lifetime is an important issue in its design. A WSN can be used to collect and process data of environment that can be, in some cases, multivariate. In this way, to help the data processing, this work proposes a multivariate sampling algorithm which uses component analysis techniques to rank the data and then to select only the data more relevant to the application. Simulation results show that our technique reduces the data keeping its representativeness. In addition, the energy consumption and delay on the network are reduced.
An architectural framework for providing QoS in IP differentiated services networks.
(2001) Trimintzios, Panos; Andrikopoulos, Ilias; Pavlou, George; Cavalcanti, Carlos Frederico Marcelo da Cunha; Georgatsos, Panos; Griffin, David; Jacquenet, C.; Goderis, D.; T'Joens, Y.; Georgiadis, Leonidas; Egan, R.; Memenios, G.
As the Internet evolves, a key consideration is support for services with guaranteed quality of service (QoS). The proposed differentiated services (DiffServ) framework, which supports aggregate traffic classes, is seen as the key technology to achieve this. DiffServ currently concentrates on control/data plane mechanisms to support QoS but also recognises the need for management plane aspects through the bandwidth broker (BB). In this paper we propose a model and architectural framework for supporting end-to-end QoS in the Internet through a combination of both management and control/data plane aspects. Within the network we consider control mechanisms for traffic engineering (TE) based both on explicitly routed paths and on pure node-by-node layer 3 routing. Management aspects include customer interfacing for service level specification (SLS) negotiation, network dimensioning, traffic forecasting and dynamic resource and routing management. All these are policy-driven in order to allow for the specification of high-level management directives. Many of the functional blocks of our architectural model are also features of BBs, the main difference being that a BB is seen as driven purely by customer requests whereas, in our approach, TE functions are continually aiming at optimising the network configuration and its performance. As such, we substantiate the notion of the BB and propose an integrated management and control architecture that will allow providers to offer both qualitative and quantitative QoS-based services while optimising the use of underlying network resources
An early warning system for space-time cluster detection.
(2003) Assunção, Renato Martins; Tavares, Andréa Iabrudi; Kulldorff, Martin
A new topic of great relevance and concern has been the design of efficient early warning systems to detect as soon as possible the emergence of spatial clusters. In particular, many applications involving spatial events recorded as they occur sequentially in time require this kind of analysis, such as fire spots in forest areas as in the Amazon, crimes occurring in urban centers, locations of new disease cases to prevent epidemics, etc. We propose a statistical method to test for the presence of space-time clusters in point processes data, when the goal is to identify and evaluate the statistical significance of localized clusters. It is based on scanning the three dimensional space with a score test statistic under the null hypothesis that the point process is an inhomogeneous Poisson point process with space and time separable first order intensity. We discuss an algorithm to carry out the test and we illustrate our method with space-time crime data from Belo Horizonte, a large Brazilian city.
An embedded converter from RS232 to universal serial bus.
(2001) Zuquim, Ana Luiza de Almeida Pereira; Coelho Júnior, Claudionor José Nunes; Fernandes, Antônio Otávio; Oliveira, Marcos Pêgo; Tavares, Andréa Iabrudi
Universal Serial Bus (USB) is a new personal computer interconnection protocol, developed to make the connection of peripheral devices to a computer easier and more efficient. It reduces the cost for the enduser, improves communication speed and supports simultaneous attachment of multiple devices (up to 127). RS232, in another hand, was designed to single device connection, but is one of the most used communication protocols. An embedded converter from RS232 to USB is very interesting, since it would allow serial-based devices to experience USB advantages without major changes. This work describes the specification and development of such converter and it is also a useful guide for implementing other USB devices. The converter specification was based on Engetron UPS’ serial communication requirements and its implementation uses a Cypress microcontroller with USB support.
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 Resende
The 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.
Balancing coordination and synchronization cost in cooperative situated multi-agent systems with imperfect communication.
(2004) Tavares, Andréa Iabrudi; Campos, Mário Fernando Montenegro
We propose a new Markov team decision model to the decentralized control of cooperative multi-agent systems with imperfect communication. Informational classes capture system’s communication semantics and uncertainties about transmitted information and stochastic transmission models, including delayed and lost messages, summarize characteristics of communication devices and protocols. This model provides a quantitative solution to the problem of balancing coordination and synchronization cost in cooperative domains, but its exact solution is computationally infeasible.We propose a generic heuristic approach, based on a off-line centralized team plan. Decentralized decision-making relies on Bayesian dynamic system estimators and decision-theoretic policy generators. These generators use system estimators to express agent’s uncertaintyabout system state and also to quantify expected effects of communication on local and external knowledge. Probabilities of external team behavior, a byproduct of policy generators, are used into system estimators to infer state transition. Experimental results concerning two previously proposed multi-agent tasks are presented, including limited communication range and reliability.
Construção de um protótipo framework e seu uso na resolução do problema de roteamento de veículos com frotas heterogêneas e janelas de tempo.
(2005) Neves, Tiago Araújo; Souza, Marcone Jamilson Freitas; Martins, Alexandre Xavier
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 Nunes
A 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)
Definição de um ambiente para apoiar a gerência do conhecimento para projeto de banco de dados utilizando um framework conceitual e padrões de análise.
(2004) Dias, Viviane Cristina; Pietrobon, Carlos Alberto Marques; Alves, Mário Fabiano
Uma das grandes dificuldades no desenvolvimento de software é que, muitas vezes, os desenvolvedores não estão familiarizados com o domínio para o qual o software está sendo desenvolvido. A necessidade de apoiar o desenvolvimento de software em domínio específicos tem sido endereçada tanto por Ambientes de Desenvolvimento de Software Orientados a Domínio (ADSODs), como pelo uso de gerência do conhecimento. Este artigo apresenta o uso de gerência do conhecimento para apoiar a orientação do domínio no Ambiente de Definição de um Banco de Dados para QEE(ADEBDQEE) utilizando um Framework Conceitual e Padrões de Análise.
Efficient allocation of verification resources using revision history information.
(2008) Nacif, José Augusto Miranda; Silva, Thiago; Tavares, Andréa Iabrudi; Fernandes, Antônio Otávio; Coelho Júnior, Claudionor José Nunes
Verifying large industrial designs is getting harder each day. he current verification methodologies are not able to guarantee bug free designs. Some recurrent questions during a design verification are: Which modules are most likely to contain undetected bugs? In wich modules the verification team should concentrate their effort? This information is very useful, because it is better to start verifying the most bug-prone modules. In this work we present a novel approach to answer these questions. In order to identify these bug rone modules the revision history of the design is used. Using information of an academic experiment, we demonstrate that there is a close between bugs/changes history and future bugs. Our results show that allocating modules for verification based on bugs/changes leaded to the coverage of 91.67% of future bugs, while random based strategy covered only 37.5% of the future work mainly focused in software engineering techniques to bugs.
Engineering the multi-service internet : MPLS and IP-based techniques.
(2001) Trimintzios, Panos; Georgiadis, Leonidas; Pavlou, George; Griffin, David; Cavalcanti, Carlos Frederico Marcelo da Cunha; Georgatsos, Panos; Jacquenet, C.
IP Differentiated Services (DiffServ) is seen as the framework to support quality of service (QoS) in the Internet in a scalable fashion, turning it to a global multiservice network. In this context, integrated service/network management and traffic control mechanisms are of paramount importance for service provisioning and network operation, aiming to satisfy the QoS requirements of contacted services while optimizing the use of underlying network resources. In this paper, after briefly introducing an architectural framework for integrated service/network management and control, we concentrate in its traffic engineering aspects comparing and contrasting two different approaches: MPLS-based explicit routed paths and IP-based hop-by-hop routing. We consider relatively longterm network dimensioning based on the requirements of contracted services and subsequent dynamic route and resource management that react in shorter time scales to statistical traffic fluctuations and varying network conditions.
Entendendo a twitteresfera brasileira.
(2011) Souza, Fabrício Benevenuto de; Silveira, Diego; Bombonato, Leonardo; Fortes, Reinaldo Silva; Pereira Junior, Álvaro Rodrigues
O Twitter vem constantemente crescendo como um importante sistema onde usuários discutem sobre tudo, expressando opiniões, visão política, orientação sexual e ate mesmo humor, como felicidade ou tristeza. Redes sociais são apontadas como locais onde usuários influenciam e são influenciados por outros sendo, portanto, ambientes perfeitos para a realização de marketing boca-a-boca, propagandas e campanhas políticas. Com o intuito de oferecer entendimento sobre o uso do Twitter no Brasil, este trabalho prove uma ampla caracterização dos usuários brasileiros no Twitter e do conteúdo postado por esses usuários. Nos correlacionamos dados demográficos brasileiros com dados da localização dos usuários do Twitter para mostrar que alguns estados brasileiros estão subestimados nesse sistema. Alem disso, n´os caracterizamos os diferentes padrões linguísticos adotados, analisamos as URLs mais propagadas, e identificamos os usuários brasileiros mais influentes no Twitter em cada região brasileira.
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 Beatrys
Auto 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.
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 Gadelha
This 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.
Evolving visual features and detectors.
(1998) Guarda, Álvaro; Le Gal, Christophe; Lux, Augustin
This paper addresses the problemof automatic synthesis of visual detectors. We present a method using genetic techniques to learn visual features and a program which combines and integrates the features in non-linear ways. The method is integrated in a face tracking system to generate a variety of new visual perceptual processes.
A framework for sensor stream reduction in wireless sensor networks.
(2011) Aquino, André Luiz Lins de
This work presents a general methodology to perform sensor stream reduction in wireless sensor networks. This methodology considers the application requirements, the reduction design, and the data reduce validation. Specifically, the reduction design, we present a architecture that can be applied to reduce the data when it is sensed or routed through to sink. The objective of this work is to show step-by-step how we can realize reduction applications in wireless sensor networks by using our methodology. The study cases show the usefulness of our methodology applied on a general sensing and a real time scenarios.
Genealogical trees on the web : a search engine user perspective.
(2008) Yates, Ricardo Baeza; Pereira Junior, Álvaro Rodrigues; Ziviani, Nivio
This paper presents an extensive study about the evolution of textual content on the Web, which shows how some new pages are created from scratch while others are created using already existing content. We show that a significant fraction of the Web is a byproduct of the latter case. We introduce the concept of Web genealogical tree, in which every page in a Web snapshot is classified into a component. We study in detail these components, characterizing the copies and identifying the relation between a source of content and a search engine, by comparing page relevance measures, documents returned by real queries performed in the past, and click-through data. We observe that sources of copies are more frequently returned by queries and more clicked than other documents.