Informática

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Programa de Pós-Graduação em Informática

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Agora exibindo 1 - 20 de 325

Um ambiente para simulação de dinâmica e controle de robôs com animação em 3D
(Universidade Federal do Espírito Santo, 2003-10-16) Vilarinho, Alessandra Aguiar; Schneebeli, Hans Jorg Andreas; Souza, Alberto Ferreira de; Bastos Filho, Teodiano Freire; Wu, Ching Ting
This work shows the use of the rigid body dynamic’s theory and the classic control’s theory as a base for simulation of robots. The simulation’s results are presented in an animation, in three dimensions, of the geometric model of the robot. This work uses theories and tools of Physics, Mathematics, Automation and Computation to solve a robotic’s problem: control and dynamic’s robot computational simulation with three dimensions animation.
O efeito da largura de Fetch no desempenho das arquiteturas super escalar, trace cache e DTSVLIW
(Universidade Federal do Espírito Santo, 2003-10-29) Freitas, Christian Daros de; Reis Junior, Neyval Costa; Souza, Alberto Ferreira de; Schneebeli, Hans Jorg Andreas; Fernandes, Edil Severiano Tavares
Superscalar machines fetch multiple scalar instructions per cycle from the instruction cache. However, machines that fetch no more than one instruction per cycle from the instruction cache, such as Dynamically Trace Scheduled VLIW (DTSVLIW) machines, have shown performance comparable to that of Superscalars. In this paper we present experiments which show that fetching a single instruction from the instruction cache per cycle allows the same performance achieved fetching multiple instructions per cycle thanks to the execution locality present in programs. We also present the first direct comparison between the Superscalars, Trace Cache and DTSVLIW architectures. Our results show that a DTSVLIW machine capable of executing up to 16 instructions per cycle can perform 21.9% better than a Superscalar and 6.6% better than a Trace Cache with equivalent hardware. In the comparison between a DTSVLIW machine and an Alpha 21264 machine, we have shown that the DTSVLIW can perform 24,17% better than Alpha using integer programs, and 60,36% better than Alpha using floating point programs.
Uma abordagem em análise de cluster para problemas de agrupamento de áreas florestais
(Universidade Federal do Espírito Santo, 2004-09-27) Moura, Alexsandro Afonso; Ahonen, Hannu Tapio; Alvarenga, Arlindo Gomes de; Lorenzoni, Luciano Lessa
abstract
Implementação de um algoritmo de mecânica dos fluidos computacional projetado para plataformas de processamento paralelo com memória distribuída
(Universidade Federal do Espírito Santo, 2005-06-30) De Angeli, João Paulo; Valli, Andréa Maria Pedrosa; Souza, Alberto Ferreira de; Reis Junior, Neyval Costa; Amorim, Cláudio Luis; Oliveira, Elias Silva de
This work discusses the implementation of a numerical algorithm for simulating incompressible fluid flows, based on the finite difference method, and designed for parallel computing platforms with distributed-memory, particularly for clusters of workstations. The solution algorithm for the Navier-Stokes equations utilizes an explicit scheme for pressure and an implicit scheme for velocities. The parallel implementation is based on domain decomposition, where the original calculation domain is decomposed into several blocks, each of which given to a separate processing node. All nodes then execute computations in parallel, each node on its associated sub-domain. The parallel computations include initialization, coefficient generation, linear solution on the sub-domain, and inter-node communication. The exchange of information across the sub-domains, or processors, is achieved using the message passing interface standard, MPI. The use of MPI ensures portability across different computing platforms ranging from massively parallel machines to clusters of workstations. Three different optimization strategies were evaluated in order to improve the computational performance of the algorithm, which include techniques exploring a reduction in the communication volume between processors and a more efficient utilization of the microprocessor s cache memory. In order to evaluate the performance levels obtained, and to analyze the effectiveness of the optimization strategies adopted, simulations using a 64 nodes cluster were executed. The simulations were performed using 2 to 56 processors, where execution time and speed-up were measured. The results indicate that the optimizations related to communication factors can improve the speed-up obtained up to 165%, while the cache memory optimization technique used can improve the speed-up obtained in further 40%.
Uma ferramenta integrada para comunicação em ambientes virtuais
(Universidade Federal do Espírito Santo, 2005-07-06) Pereira, Otacílio José; Menezes, Credine Silva de; Oliveira, Elias Silva de; Gava, Tânia Barbosa Salles
It deals with a conception of an integrated communication and on-line tool, FACIO , whose target is to make the written messages management easier, which are elaborated in organized chat groups by themes. This tool searchs to atack two current problems: the great volume of interactions and contacts that someone has to manage and, with the scattered way this interactions happen. The tool is within the computer mediated communication (CMC) and in relation to face to face, the tools of CMC present deficiencies connected to the loss of conversation context in the chats and the loss of social and affective perception in the groups. Among the several proposed strategies, the use of the techniques of the information visualization area is one that is discussed. The application scenario is the teaching and learning, therefore some hypothetical aspects about the social relation among the ones involved are presented and correlated to the use of the tool. Some facilitator conditions to a situation of learning, of humanistic aspect, are also commented. By intending the dominion s exploration in a comprising way and with no commitment with a particular technology. The ontologies were an instrument of support to the used methodology. About the tool s resources, the integration is an important feature. For instance, synchronized and unsynchronized chats that usually are realized by various tools can be treated in an integrated and ortogonal way with FACIO.
Uma modelagem computacional de áreas corticais do sistema visual humano associadas à percepção de profundidade
(Universidade Federal do Espírito Santo, 2005-07-15) Oliveira, Hallysson; Reis Junior, Neyval Costa; Souza, Alberto Ferreira de; Lima, Priscila Machado Vieira; Silva, Laércio Evandro Ferracioli da; Oliveira, Elias Silva de
The images formed on the human retinas has only two dimensions, however the brain is capable of synthesizing a three-dimensional representation with color, shape and depth information about the environment surroundings. For in such a way, after choosing a point in the 3-D space, the eyes verge to this fixation point and, at the same time, the visual system is fed back with eyes placement information, supplied by ocular motor system, considering them as the distance of this point to the observer. The depth perception around the vergence point may be got by estimating the disparity, the positional difference between the two retinal projections of a given point in space results from the horizontal separation of the eyes. Most of the depth perception processing is done by visual cortex, mainly in V1 and MT areas. This work presents a modeling and implementation of a mathematical computational neural architecture that represents the V1 and MT cortical areas, based in visual cortex neurophysiology, used to create in a computer a 3-D representation of the surrounds, using images from two cameras connected to this computer. This model implementation was based upon Gabor filters and log-polar mapping. With this model it is possible to make a disparity map of the images and thus calculate the 3-D spatial position of each image point represented in the disparity map. This way it is possible to create a 3-D representation of the surrounds in a computer.
Multiplex: um procedimento baseado em simulted annealing aplicado ao problema Max-Sat ponderado
(Universidade Federal do Espírito Santo, 2006-04-07) Teixeira, Giovany Frossard; Provedel, Attílio; Alvarenga, Arlindo Gomes de; Ochi, Luiz Satoru; Ahonen, Hannu Tapio
abstract
Um protocolo de descoberta de servirço para sistemas sensíveis ao contexto
(Universidade Federal do Espírito Santo, 2006-05-12) Carmo, Ricardo Rios Monteiro do; Souza, Wanderley Lopes de; Pereira Filho, José Gonçalves; Santos, José Laurindo Campos dos; Freitas, Sergio Antônio Andrade de
Advances in mobile computing and wireless technology are allowing the raising of new computing paradigms. One of them is the Ubiquitous or Pervasive Computing, which is characterised by a highly dynamic environment caused by the user mobility and by the massive use of small mobile devices like PDAs and cellular phones. Ubiquitous Computing allows to explore a new set of applications, the Context-Aware Applications. Theses applications use contextual information, allowing more exible, adaptable, rich in functionality and user-centred services to be developed. However, context-aware applications require an infrastructure prepared to deal with the nature of the contextual information is needed. Among the many proposed context-aware infrastructures, Infraware has been developed in the Network and Multimedia Research Laboratory of the Federal University of Espírito Santo. Infraware proposes an integrated management model of services that emphasises composition and discovery of services based on semantic description. In particular, the service discovery has an important role because it is used by the applications to find the right services to execute their tasks. In Pervasive Computing environments, service discovery must consider the nature of the contextual information. Few discovery mechanisms and protocols consider contextual information in the selection process. Moreover, some of them do not consider security and authentication of data. This master thesis proposes a secure and context-aware service discovery protocol, named SCaSDP, which is part of the Service Manager Module of the Infraware platform. This protocol presents a generic architecture, allowing its use in many situations of service discovery.
Uma abordagem baseada em conhecimento para apoio ao combate às perdas comerciais na distribuição de energia elétrica
(Universidade Federal do Espírito Santo, 2006-05-30) Dias, Hélder Bergamin Pimentel; Varejão, Flávio Miguel; Garcia, Ana Cristina Bicharra; Garcia, Berilhes Borges
Frauds and measure failures in Power Distribution cause great losses to Power Companies. A traditional way to combat these problems is performing field inspections on customers. However, selecting customers to be inspected is a difficult task for experts on such domain. The goal of the present work is to analyze such knowledge and propose a knowledge based system able to acquire, modify and apply heuristics obtained from the experts on the customer selection process. The system used a real customer database of the local power distribution company for selecting customers for inspection. The evaluation of the results was carried out through two different strategies: executing real field inspections on the selected customers and comparing the results with previously performed field inspections.
Um ambiente de apoio ao desenvolvimento de projetos de aprendizagem
(Universidade Federal do Espírito Santo, 2006-06-02) Monteiro, Valéria Cristina Pelinzzer Cauper; Cury, Davidson; Menezes, Credine Silva de; Tavares, Orivaldo de Lira; Nevado, Rosane Aragón de
The development of Learning Projects is a pedagogical practical based in the knowledge construction that comes being tried in some schools of the country. Evaluating the tools requirements for the cooperative construction of sites in the Web and the tools of content publication, we understand that the exploration of its potential still requires the development of specific tools, more syntonized with its conception. This work considers a model that was created from discussion with teachers who work with learning projects and the analysis of tools for cooperative construction of sites in the Web. Based in this model a first version of the considered environment was created that allows to the development and accompaniment of learning projects.
Definição de processos em um ambiente de desenvolvimento de software
(Universidade Federal do Espírito Santo, 2006-06-13) Bertollo, Gleidson; Falbo, Ricardo de Almeida; Gava, Tânia Barbosa Salles; Guizzardi, Giancarlo
Nowadays, it is widely recognized that the quality of a software product depends on the quality of the software processes used in its development and maintenance. With this, much work has been done aiming to support organizations in their efforts towards process quality. The software process research area has explored two main directions: (i) approaches for modeling, analyzing and improving software processes, and (ii) support technology for software processes. The first goal focuses on approaches for structuring, organizing, documenting and describing software processes and includes process quality standards and maturity models. The second goal is concerned with the development of Process-Centered Software Engineering Environments (PSEEs) that integrate tool support for the development of artifacts with tool support for software process modeling and execution. The explicit representation of processes, its products and its interactions are the basis over which the modern development environments are built. Providing more powerful ways of describing and implementing software processes, PSEEs have also provided a powerful way to integrate processes and tools, and to automate, at least partially, tasks. This work presents a software process infrastructure that includes a tool for defining software processes. This tool was built and integrated to ODE (Ontology-based software Development Environment). To support this integration, the proposed infrastructure was built based on a software process ontology. This ontology was evolved in the context of this work, taking into account recent quality models and standards.
Semântica em um ambiente de desenvolvimento de software
(Universidade Federal do Espírito Santo, 2006-06-21) Ruy, Fabiano Borges; Falbo, Ricardo de Almeida; Cury, Davidson; Guizzardi, Renata Silva Souza
Software development is a complex task. One of the biggest challenges of Software Engineering is to produce software satisfying restrictions as time, cost, and quality. Software Engineering Environments (SEEs) try to provide a collection of tools, methods, and techniques to support the software engineer in this task. To offer a more effective support, in the last years, the introduction and management of knowledge in SEEs became indispensable. SEEs have been incorporating several types of knowledge, including software engineering, application domains, and organizational knowledge. During SEEs evolution, the need for the application of semantics becomes more and more evident, given characteristics such as the complex nature of Software Engineering, the integration premise of SEEs, and the great amount of information they store. In this context, ontologies and inference machines are key technologies to allow more adequate knowledge management and to provide a wider support to users. This work presents how ontologies have been used in ODE (Ontology-based software Development Environment), to make it a Semantic SEE (SSEE). For that, we developed a Software Organization Ontology to incorporate organizational knowledge to the environment. The work also proposes an infrastructure to provide semantic services based on ontological knowledge, aiming to facilitate and disseminate the use of semantics in ODE environment.
Uma abordagem heurística para o problema de otimização de distrito postal
(Universidade Federal do Espírito Santo, 2006-06-23) Fiório, Rafael Carpanedo; Alvarenga, Arlindo Gomes de; Provedel, Attílio; Lorenzoni, Luciano Lessa; Conceição, Samuel Vieira
This study proposes a strategia solution for the optimized construction of postal districts. Postal District is a set of segments of publics areas connecteds. Given a locality composed of uncounted segments of publics areas, this study proposes an arrangement of connects subgroups of publics areas with the goal of composing a postal district. The strategy is to transform the system of public areas of a place in a graph and from this graph, to extract their respective cyclical subgraphs that are understood as atomics entities. Those atomics entities are submited by an assembly process until compose a group of postal districts. The methodology here presented divides the study in two different phases: the first one understands the process of obtaining of the cyclical subgraphs; and the second one is understood as the assembly process of postal district The process of obtaining of cyclical subgraph consists in the obtaining of the hull convex of the graph and subsequent extracting up the cyclical subgraphs tangent to edge of that. That is, in a sequential way, in other words, it is determined the first convex hull of the graph and extract up their respective tangent subgraphs; it is determined the second convex hull and extract up their subgraphs and so forth. The study of determination of the convex hull and extracting of the cyclical subgraphs is done through operations of the computational geometry. The process of construction of the postal districts is given through the clustering of the cyclicals subgraphs, using as a tool the meta- heuristic Simulated Annealing. The Chinese Postman's Problem and Capacited Chinese Postman's Problem are formulations support for the present study. The main objective of the study is to obtain, in a fast and efficient way the optimized postal district, with smaller unproductive course possible, offering agility for the process of domiciliary distribution of postal objects.
Reconhecimento facial baseado em Gabor Wavelets com foveação
(Universidade Federal do Espírito Santo, 2006-09-10) Santos, Thiago Oliveira dos; Rauber, Thomas Walter; Facon, Jacques; Souza, Alberto Ferreira de
Due to the complexity and the high number of variables involved in the management activities, it is essential to the project manager to have some kind of automated support to perform her tasks. During the accomplishment of a software project, a high amount of knowledge is produced and used. Looking for the reuse of that knowledge in future projects, we need to provide means to retain and store the generated knowledge in a way to minimize the effort to obtain it in the future. In this context, knowledge management can be used to capture the knowledge and experience generated and accumulated during the software process and to promote the appearance of new knowledge. Experience constitutes a key factor in order to management activities can be accomplished with success. Thus, the benefits reached by the change of ideas during the accomplishment of those activities are evident. During this work, in order to support software project management using knowledge management in the software development environment ODE, we have developed and integrated to ODE an infrastructure to support software items characterization and search for similar items and an infrastructure to support group decision. To evaluate the potential of these infrastructures, we specialized them, respectively, to support project characterization and cooperative elaboration of risk plans.
Processos e ferramentas para o desenvolvimento de software livre: um estudo de caso
(Universidade Federal do Espírito Santo, 2006-10-03) Silva, Bruno Carreira Coutinho; Falbo, Ricardo de Almeida; Freitas, Sergio Antônio Andrade de; Pietrobon, Carlos Alberto Marques
Free Software is more and more earning space in software market. Nowadays, there are several projects of this kind in progress around the world. This new software development model brings along a new philosophy, affecting many of the software industry principles. Despite of its importance and growth, in most cases, free software development is not being done according to the best practices of Software Engineering. In this scenario, many times software processes are not formally defined. This paper discusses an effort for defining a standard process for free software projects at LabES/UFES. The initial goal of defining these processes is to apply it in ODE´s Project, a project that aims to develop a software engineering environment as a free software The goal of this work is to define an infrastructure to support free software projects at LabES/UFES, which includes standard software processes for open source software projects, as well as the definition of requirements for the development of an environment that is able to support the processes defined. This infrastructure is to be applied to ODE Project, a project that aims to develop the software engineering environment ODE (Ontology-based software Development Environment) as a free software, giving rise to the Free ODE Project. ODE Project aims to develop a Process Centered Software Development Environment and it is the main project in progress in the Software Engineering Laboratory of the Federal University of Espírito Santo (LabES/UFES).
Infraware: um middleware de suporte a aplicações sensíveis ao contexto
(Universidade Federal do Espírito Santo, 2006-10-25) Pessoa, Rodrigo Mantovaneli; Pereira Filho, José Gonçalves; Endler, Markus; Farias, Clever Ricardo Guareis de; Guizzardi, Giancarlo
New mobile computing technologies and the increasing use of portable devices make computers more present on human life activities with each passing day. This favors the rising of a new computing paradigm: the Ubiquitous Computing. In this scenario, context-aware mobile applications stand out among others, improving user interaction by supporting new adaptive behavior according to context changes. Recent research points out the need for developing specialized middleware infrastructure for the management of dynamic contextual information. These new infrastructures provide the adequate facilities for the development of a large range of contextaware mobile applications, in several domains. This work proposes the design of a middleware to support the development and execution of context-aware applications. The architecture is defined by using relevant functional requirements of this new class of applications. Related aspects of the middleware s main components are presented. This work also presents the design and implementation of an essential component of the proposed middleware, responsable for the inference of new context information and context perception.
Análise comparativa de Wavelets para detecção de fenômenos oceanográficos relacionados à temperatura de superfície do mar em imagens adquiridas por satélite
(Universidade Federal do Espírito Santo, 2006-11-24) Souza, Paulo Roberto Nunes de; Silva, Mara Regina Labuto Fragoso da; Chacaltana, Júlio Tomás Aquije; Catabriga, Lúcia; Sartori Neto, Angelo
The Remote Sensing arouses interest from general people, productive sector and research. Several fields can benefit of analytic and virtually omnipresent view of the satellites. When applied to oceanography, the advantages of remote sensing over traditional methods are as big as the oceans. With the possibility to acquire images of virtually anywhere over the planet, the challenge becomes to analyze these data and extract important information. The explored method in this work was to extract information using signal spectral analysis techniques, especially Wavelet Transform. The defined objectives were: to evaluate the potential of Wavelet Analysis to identify oceanographic phenomena related to the Sea Surface Temperature on digital images acquired from satellites, to define a methodology to choose Wavelet functions to be used and to compare the results of the chosen Wavelets. As digital images from satellites were discrete data, it was used a methodology based on the Discrete Wavelet Analyses. The Discrete Wavelet Analyses uses the filter banks theory, where the original data is processed by a set of filters to result in a Wavelet processed data. The chosen Wavelet Function defines the set of filters to be used. At the used methodology the filter bank was applied to blocks of the original images, generating results representing the wavelet application to each block. The processed data was then submitted to a classification function. This function grouped the blocks based at the wavelet result and a previously chosen threshold. At the end of the process there were an image proportionally segmented to the response of the Wavelet applied to each block of the original image. Using this methodology it was possible to segment digital images of the Sea Surface Temperature acquired by satellites, providing a way to identify several thermal phenomena on the ocean surface a classify the used Wavelets according to the results quality of them.
Gerência de conhecimento e decisão em grupo: um estudo de caso na gerência de projetos
(Universidade Federal do Espírito Santo, 2006-11-27) Carvalho, Victorio Albani de; Falbo, Ricardo de Almeida; Cury, Davidson; Araújo, Renata Mendes de
Due to the complexity and the high number of variables involved in the management activities, it is essential to the project manager to have some kind of automated support to perform her tasks. During the accomplishment of a software project, a high amount of knowledge is produced and used. Looking for the reuse of that knowledge in future projects, we need to provide means to retain and store the generated knowledge in a way to minimize the effort to obtain it in the future. In this context, knowledge management can be used to capture the knowledge and experience generated and accumulated during the software process and to promote the appearance of new knowledge. Experience constitutes a key factor in order to management activities can be accomplished with success. Thus, the benefits reached by the change of ideas during the accomplishment of those activities are evident. During this work, in order to support software project management using knowledge management in the software development environment ODE, we have developed and integrated to ODE an infrastructure to support software items characterization and search for similar items and an infrastructure to support group decision. To evaluate the potential of these infrastructures, we specialized them, respectively, to support project characterization and cooperative elaboration of risk plans.
Sistema imune artificial para o problema de escalonamento Job Shop
(Universidade Federal do Espírito Santo, 2006-11-29) Ribeiro, Sildenir Alves; Alvarenga, Arlindo Gomes de; Ahonen, Hannu Tapio; Provedel, Attílio; Conceição, Samuel Vieira
This work presents an Artificial Immune System (AIS) to deal with problems scheduling. The Artificial Immunologic System developed in this project was based on the structure, architecture and functioning of the Biological or Natural Immune Systems. The use of Genetic Algorithm (GA) became necessary to represent the antibodies and antigens of the AIS. Each individual generated for the GA represented a processed task set library in a set of machines. The evaluation of each individual was given by a fitness function that represents the process of natural selection. The evolution of the individuals, and population as a consequence was obtained by applying the genetic operators of crossover e mutation. The machines and the tasks used for the scheduling represent the problem of Job Shop Scheduling (JSS). Some classic tests of the literature where applied to the problem in order to verify the viability of the AIS on the treatment of task of scheduling problems. Those tests also demonstrated the system s behavior its entire execution, therefore, allowing for a detailed analysis of the system s functionalities sets for certain time period. The representation of the natural immunologic systems through computational algorithms inspires from all over world researchers. The motivation is that the immunologic systems possess parallelism characteristics adaptability and learning, which can be applied in several problems found in many areas, had its portability.
Otimização de índices de confiabilidade em redes de distribuição de energia elétrica
(Universidade Federal do Espírito Santo, 2006-12-04) Zambon, Eduardo; Freitas, Sergio Antônio Andrade de; Garcia, Berilhes Borges; Varejão, Flávio Miguel; Nepomuceno, Leonardo
An eletric utility must install protection (reclosers and fuses) and sectionalizing (switches) devices in key points of its distribution network to serve its customers with a reliable power supply. Utility boards or similar commissions define measures (reliability indices) to quantify and analize the eletric utility services. The problem addressed in this work is twofold. First, we want to optimize the allocation of reclosers in a distribution network to improve its reliability indices. The Simulated Annealing meta-heuristic was employed and its results were close to the optimal values in the tests performed. Second, we want to improve the effectiveness of a distribution protective design by identifying the type (recloser, fuse or switch) and location of devices to be installed. A Binary Linear Programming model found in the literature was implemented and tested. Its deficiencies leaded to the development of a more complete Binary Nonlinear Programming model and a specific branch-and-bound algorithm to solve it. The solutions proposed in this work allow an eletric utility to project and restructure the protection design of its distribution networks, allowing it to improve the service provided to its consumers. Hence, the company can cut investiments costs and still ensure a better quality of service to its clients, generating economic benefits to both parties.

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