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Harmonic identification using parallel neural networks in single-phase systems

NASCIMENTO, Claudionor Francisco do; OLIVEIRA JR., Azauri Albano de; GOEDTEL, Alessandro; SERNI, Paulo Jose Amaral
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.52572%
In this paper, artificial neural networks are employed in a novel approach to identify harmonic components of single-phase nonlinear load currents, whose amplitude and phase angle are subject to unpredictable changes, even in steady-state. The first six harmonic current components are identified through the variation analysis of waveform characteristics. The effectiveness of this method is tested by applying it to the model of a single-phase active power filter, dedicated to the selective compensation of harmonic current drained by an AC controller. Simulation and experimental results are presented to validate the proposed approach. (C) 2010 Elsevier B. V. All rights reserved.; CNPq[142128/2005-8]; CNPq[474290/2008-5]; FAPESP[06/56093-3]

Noise reduction in biomedical speech signal processing based on time and frequency Kalman filtering combined with spectral subtraction

SILVA, Leandro Aureliano da; JOAQUIM, Marcelo Basilio
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.52572%
The goal of this paper is to study and propose a new technique for noise reduction used during the reconstruction of speech signals, particularly for biomedical applications. The proposed method is based on Kalman filtering in the time domain combined with spectral subtraction. Comparison with discrete Kalman filter in the frequency domain shows better performance of the proposed technique. The performance is evaluated by using the segmental signal-to-noise ratio and the Itakura-Saito`s distance. Results have shown that Kalman`s filter in time combined with spectral subtraction is more robust and efficient, improving the Itakura-Saito`s distance by up to four times. (C) 2007 Elsevier Ltd. All rights reserved.

The choice of the best among the shortest routes in transparent optical networks

DURAES, Gilvan M.; SOARES, Andre; Amazonas, Jose Roberto de Almeida; Giozza, William Ferreira
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.532056%
This work introduces the problem of the best choice among M combinations of the shortest paths for dynamic provisioning of lightpaths in all-optical networks. To solve this problem in an optimized way (shortest path and load balance), a new fixed routing algorithm, named Best among the Shortest Routes (BSR), is proposed. The BSR`s performance is compared in terms of blocking probability and network utilization with Dijkstra`s shortest path algorithm and others algorithms proposed in the literature. The evaluated scenarios include several representative topologies for all-optical networking and different wavelength conversion architectures. For all studied scenarios, BSR achieved superior performance. (C) 2010 Elsevier B.V. All rights reserved.

Supporting content-based image retrieval and computer-aided diagnosis systems with association rule-based techniques

RIBEIRO, Marcela X.; BUGATTI, Pedro H.; TRAINA JR., Caetano; MARQUES, Paulo M. A.; ROSA, Natalia A.; TRAINA, Agma J. M.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.723203%
In this work, we take advantage of association rule mining to support two types of medical systems: the Content-based Image Retrieval (CBIR) systems and the Computer-Aided Diagnosis (CAD) systems. For content-based retrieval, association rules are employed to reduce the dimensionality of the feature vectors that represent the images and to improve the precision of the similarity queries. We refer to the association rule-based method to improve CBIR systems proposed here as Feature selection through Association Rules (FAR). To improve CAD systems, we propose the Image Diagnosis Enhancement through Association rules (IDEA) method. Association rules are employed to suggest a second opinion to the radiologist or a preliminary diagnosis of a new image. A second opinion automatically obtained can either accelerate the process of diagnosing or to strengthen a hypothesis, increasing the probability of a prescribed treatment be successful. Two new algorithms are proposed to support the IDEA method: to pre-process low-level features and to propose a preliminary diagnosis based on association rules. We performed several experiments to validate the proposed methods. The results indicate that association rules can be successfully applied to improve CBIR and CAD systems...

Symmetry breaking in the genetic code: Finite groups

ANTONELI, Fernando; FORGER, Michael
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.532056%
We investigate the possibility of interpreting the degeneracy of the genetic code, i.e., the feature that different codons (base triplets) of DNA are transcribed into the same amino acid, as the result of a symmetry breaking process, in the context of finite groups. In the first part of this paper, we give the complete list of all codon representations (64-dimensional irreducible representations) of simple finite groups and their satellites (central extensions and extensions by outer automorphisms). In the second part, we analyze the branching rules for the codon representations found in the first part by computational methods, using a software package for computational group theory. The final result is a complete classification of the possible schemes, based on finite simple groups, that reproduce the multiplet structure of the genetic code. (C) 2010 Elsevier Ltd. All rights reserved.; FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico), Brazil; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Particle Competition and Cooperation in Networks for Semi-Supervised Learning

Breve, Fabricio; Liang, Zhao; Quiles, Marcos; Pedrycz, Witold; Liu, Jiming
Fonte: IEEE COMPUTER SOC; LOS ALAMITOS Publicador: IEEE COMPUTER SOC; LOS ALAMITOS
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.634365%
Semi-supervised learning is one of the important topics in machine learning, concerning with pattern classification where only a small subset of data is labeled. In this paper, a new network-based (or graph-based) semi-supervised classification model is proposed. It employs a combined random-greedy walk of particles, with competition and cooperation mechanisms, to propagate class labels to the whole network. Due to the competition mechanism, the proposed model has a local label spreading fashion, i.e., each particle only visits a portion of nodes potentially belonging to it, while it is not allowed to visit those nodes definitely occupied by particles of other classes. In this way, a "divide-and-conquer" effect is naturally embedded in the model. As a result, the proposed model can achieve a good classification rate while exhibiting low computational complexity order in comparison to other network-based semi-supervised algorithms. Computer simulations carried out for synthetic and real-world data sets provide a numeric quantification of the performance of the method.; State of Sao Paulo Research Foundation (FAPESP); Brazilian National Council of Technological and Scientific Development (CNPq)

Hybrid heuristic-waterfilling game theory approach in MC-CDMA resource allocation

Sampaio, Lucas Dias Hiera; Abrao, Taufik; Angelico, Bruno Augusto; Lima, Moises Fernando; Proenca Jr., Mario Lemes; Jeszensky, Paul Jean Etienne
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.532056%
This paper discusses the power allocation with fixed rate constraint problem in multi-carrier code division multiple access (MC-CDMA) networks, that has been solved through game theoretic perspective by the use of an iterative water-filling algorithm (IWFA). The problem is analyzed under various interference density configurations, and its reliability is studied in terms of solution existence and uniqueness. Moreover, numerical results reveal the approach shortcoming, thus a new method combining swarm intelligence and IWFA is proposed to make practicable the use of game theoretic approaches in realistic MC-CDMA systems scenarios. The contribution of this paper is twofold: (i) provide a complete analysis for the existence and uniqueness of the game solution, from simple to more realist and complex interference scenarios; (ii) propose a hybrid power allocation optimization method combining swarm intelligence, game theory and IWFA. To corroborate the effectiveness of the proposed method, an outage probability analysis in realistic interference scenarios, and a complexity comparison with the classical IWFA are presented. (C) 2011 Elsevier B.V. All rights reserved.; National Council for Scientific and Technological Development (CNPq) of Brazil; National Council for Scientific and Technological Development (CNPq) of Brazil [303426/2009-8]

An in-depth analysis of the HIV-1/AIDS dynamics by comprehensive mathematical modeling

Joly, Marcel; Pinto, Jose M.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD Publicador: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.516367%
This work presents major results from a novel dynamic model intended to deterministically represent the complex relation between HIV-1 and the human immune system. The novel structure of the model extends previous work by representing different host anatomic compartments under a more in-depth cellular and molecular immunological phenomenology. Recently identified mechanisms related to HIV-1 infection as well as other well known relevant mechanisms typically ignored in mathematical models of HIV-1 pathogenesis and immunology, such as cell-cell transmission, are also addressed. (C) 2011 Elsevier Ltd. All rights reserved.; FAPESP; FAPESP [99/09897-4]

Research in Computer Science and Computer Engineering

Feldman, J. A. ; Merriam, C. W.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
Português
Relevância na Pesquisa
66.892695%
This report describes many of the computer related research efforts at the University of Rochester. The Department of Computer Science is involved in research in automatic programming, including very high level languages and data structures; machine perception; and in problem solving using combinations of traditional heuristic methods, artificial intelligence,and utility theory. The research of the Department of Electrical Engineering includes basic computer engineering research in the construction of computer systems and operating systems, research in image processing and in numerical methods, and research in production automation which is concerned with mechanical manufacturing and assembly, and is currently developing mathematical models of parts, raw materials and tools. In conjunction with other departments, Electrical Engineering is also using computers for biomedical applications including ultrasound diagnostic techniques for heart disease, and pattern recognition techniques for detection of cancer from PAP smears.

Research in Computer Science and Computer Engineering

Feldman, J. A. ; Merriam, C. W.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
Português
Relevância na Pesquisa
66.892695%
This report describes many of the computer related research efforts at the University of Rochester. The Department of Computer Science is involved in research in automatic programming, including very high level languages and data structures; machine perception; and in problem solving using combinations of traditional heuristic methods, artificial intelligence,and utility theory. The research of the Department of Electrical Engineering includes basic computer engineering research in the construction of computer systems and operating systems, research in image processing and in numerical methods, and research in production automation which is concerned with mechanical manufacturing and assembly, and is currently developing mathematical models of parts, raw materials and tools. In conjunction with other departments, Electrical Engineering is also using computers for biomedical applications including ultrasound diagnostic techniques for heart disease, and pattern recognition techniques for detection of cancer from PAP smears.

Science Fiction as a Worldwide Phenomenon: A Study of International Creation, Consumption and Dissemination

Wells, Elysia
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 06/08/2013 Português
Relevância na Pesquisa
66.813135%
This paper examines the international nature of science fiction. The focus of this research is to determine whether science fiction is primarily English speaking and Western or global; being created and consumed by people in non-Western, non-English speaking countries? Science fiction's international presence was found in three ways, by network analysis, by examining a online retailer and with a survey. Condor, a program developed by GalaxyAdvisors was used to determine if science fiction is being talked about by non-English speakers. An analysis of the international Amazon.com websites was done to discover if it was being consumed worldwide. A survey was also conducted to see if people had experience with science fiction. All three research methods revealed similar results. Science fiction was found to be international, with science fiction creators originating in different countries and writing in a host of different languages. English and non-English science fiction was being created and consumed all over the world, not just in the English speaking West.; Comment: Presented at COINs13 Conference, Chile, 2013 (arxiv:1308.1028)

Quantifying Creativity in Art Networks

Elgammal, Ahmed; Saleh, Babak
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/06/2015 Português
Relevância na Pesquisa
66.877456%
Can we develop a computer algorithm that assesses the creativity of a painting given its context within art history? This paper proposes a novel computational framework for assessing the creativity of creative products, such as paintings, sculptures, poetry, etc. We use the most common definition of creativity, which emphasizes the originality of the product and its influential value. The proposed computational framework is based on constructing a network between creative products and using this network to infer about the originality and influence of its nodes. Through a series of transformations, we construct a Creativity Implication Network. We show that inference about creativity in this network reduces to a variant of network centrality problems which can be solved efficiently. We apply the proposed framework to the task of quantifying creativity of paintings (and sculptures). We experimented on two datasets with over 62K paintings to illustrate the behavior of the proposed framework. We also propose a methodology for quantitatively validating the results of the proposed algorithm, which we call the "time machine experiment".; Comment: This paper will be published in the sixth International Conference on Computational Creativity (ICCC) June 29-July 2nd 2015...

Dominating Manipulations in Voting with Partial Information

Conitzer, Vincent; Walsh, Toby; Xia, Lirong
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/06/2011 Português
Relevância na Pesquisa
66.81969%
We consider manipulation problems when the manipulator only has partial information about the votes of the nonmanipulators. Such partial information is described by an information set, which is the set of profiles of the nonmanipulators that are indistinguishable to the manipulator. Given such an information set, a dominating manipulation is a non-truthful vote that the manipulator can cast which makes the winner at least as preferable (and sometimes more preferable) as the winner when the manipulator votes truthfully. When the manipulator has full information, computing whether or not there exists a dominating manipulation is in P for many common voting rules (by known results). We show that when the manipulator has no information, there is no dominating manipulation for many common voting rules. When the manipulator's information is represented by partial orders and only a small portion of the preferences are unknown, computing a dominating manipulation is NP-hard for many common voting rules. Our results thus throw light on whether we can prevent strategic behavior by limiting information about the votes of other voters.; Comment: 7 pages by arxiv pdflatex, 1 figure. The 6-page version has the same content and will be published in Proceedings of the Twenty-Fifth AAAI Conference on Artificial Intelligence (AAAI-11)

Examples as Interaction: On Humans Teaching a Computer to Play a Game

Kalles, Dimitris; Fykouras, Ilias
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/11/2009 Português
Relevância na Pesquisa
66.831274%
This paper reviews an experiment in human-computer interaction, where interaction takes place when humans attempt to teach a computer to play a strategy board game. We show that while individually learned models can be shown to improve the playing performance of the computer, their straightforward composition results in diluting what was earlier learned. This observation suggests that interaction cannot be easily distributed when one hopes to harness multiple human experts to develop a quality computer player. This is related to similar approaches in robot task learning and to classic approaches to human learning and reinforces the need to develop tools that facilitate the mix of human-based tuition and computer self-learning.; Comment: 15 pages, 1 figure, 13 tables, submitted to a journal

On Choosing Committees Based on Approval Votes in the Presence of Outliers

Dey, Palash; Misra, Neeldhara; Narahari, Y.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 13/11/2015 Português
Relevância na Pesquisa
66.8611%
We study the computational complexity of committee selection problem for several approval-based voting rules in the presence of outliers. Our first result shows that outlier consideration makes committee selection problem intractable for approval, net approval, and minisum approval voting rules. We then study parameterized complexity of this problem with five natural parameters, namely the target score, the size of the committee (and its dual parameter, the number of candidates outside the committee), the number of outliers (and its dual parameter, the number of non-outliers). For net approval and minisum approval voting rules, we provide a dichotomous result, resolving the parameterized complexity of this problem for all subsets of five natural parameters considered (by showing either FPT or W[1]-hardness for all subsets of parameters). For the approval voting rule, we resolve the parameterized complexity of this problem for all subsets of parameters except one. We also study approximation algorithms for this problem. We show that there does not exist any alpha(.) factor approximation algorithm for approval and net approval voting rules, for any computable function alpha(.), unless P=NP. For the minisum voting rule, we provide a pseudopolynomial (1+eps) factor approximation algorithm.

On Measuring the Impact of Human Actions in the Machine Learning of a Board Game's Playing Policies

Kalles, Dimitris
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/11/2006 Português
Relevância na Pesquisa
66.829106%
We investigate systematically the impact of human intervention in the training of computer players in a strategy board game. In that game, computer players utilise reinforcement learning with neural networks for evolving their playing strategies and demonstrate a slow learning speed. Human intervention can significantly enhance learning performance, but carry-ing it out systematically seems to be more of a problem of an integrated game development environment as opposed to automatic evolutionary learning.; Comment: Contains 19 pages, 10 figures, 8 tables. Submitted to a journal

Understanding Design Fundamentals: How Synthesis and Analysis Drive Creativity, Resulting in Emergence

Kryssanov, V. V.; Tamaki, H.; Kitamura, S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 25/05/2006 Português
Relevância na Pesquisa
66.879014%
This paper presents results of an ongoing interdisciplinary study to develop a computational theory of creativity for engineering design. Human design activities are surveyed, and popular computer-aided design methodologies are examined. It is argued that semiotics has the potential to merge and unite various design approaches into one fundamental theory that is naturally interpretable and so comprehensible in terms of computer use. Reviewing related work in philosophy, psychology, and cognitive science provides a general and encompassing vision of the creativity phenomenon. Basic notions of algebraic semiotics are given and explained in terms of design. This is to define a model of the design creative process, which is seen as a process of semiosis, where concepts and their attributes represented as signs organized into systems are evolved, blended, and analyzed, resulting in the development of new concepts. The model allows us to formally describe and investigate essential properties of the design process, namely its dynamics and non-determinism inherent in creative thinking. A stable pattern of creative thought - analogical and metaphorical reasoning - is specified to demonstrate the expressive power of the modeling approach; illustrative examples are given. The developed theory is applied to clarify the nature of emergence in design: it is shown that while emergent properties of a product may influence its creative value...

Oracle Complexity and Nontransitivity in Pattern Recognition

Bulitko, Vadim
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 16/10/2000 Português
Relevância na Pesquisa
66.81329%
Different mathematical models of recognition processes are known. In the present paper we consider a pattern recognition algorithm as an oracle computation on a Turing machine. Such point of view seems to be useful in pattern recognition as well as in recursion theory. Use of recursion theory in pattern recognition shows connection between a recognition algorithm comparison problem and complexity problems of oracle computation. That is because in many cases we can take into account only the number of sign computations or in other words volume of oracle information needed. Therefore, the problem of recognition algorithm preference can be formulated as a complexity optimization problem of oracle computation. Furthermore, introducing a certain "natural" preference relation on a set of recognizing algorithms, we discover it to be nontransitive. This relates to the well known nontransitivity paradox in probability theory. Keywords: Pattern Recognition, Recursion Theory, Nontransitivity, Preference Relation

Fundamental Concepts in the Cyclus Fuel Cycle Simulator Framework

Huff, Kathryn D.; Gidden, Matthew J.; Carlsen, Robert W.; Flanagan, Robert R.; McGarry, Meghan B.; Opotowsky, Arrielle C.; Schneider, Erich A.; Scopatz, Anthony M.; Wilson, Paul P. H.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/09/2015 Português
Relevância na Pesquisa
66.813545%
As nuclear power expands, technical, economic, political, and environmental analyses of nuclear fuel cycles by simulators increase in importance. To date, however, current tools are often fleet-based rather than discrete and privately distributed rather than open source. Each of these choices presents a challenge to modeling fidelity, generality, efficiency, robustness, and scientific transparency. The Cyclus nuclear fuel cycle simulator framework and its modeling ecosystem incorporate modern insights from simulation science and software architecture to solve these problems so that challenges in nuclear fuel cycle analysis can be better addressed. A summary of the Cyclus fuel cycle simulator framework and its modeling ecosystem are presented. Additionally, the implementation of each is discussed in the context of motivating challenges in nuclear fuel cycle simulation. Finally, the current capabilities of Cyclus are demonstrated for both open and closed fuel cycles.

Managing conflicts between users in Wikipedia

Jacquemin, Bernard; Lauf, Aurélien; Poudat, Céline; Hurault-Plantet, Martine; Auray, Nicolas
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/05/2008 Português
Relevância na Pesquisa
66.81547%
Wikipedia is nowadays a widely used encyclopedia, and one of the most visible sites on the Internet. Its strong principle of collaborative work and free editing sometimes generates disputes due to disagreements between users. In this article we study how the wikipedian community resolves the conflicts and which roles do wikipedian choose in this process. We observed the users behavior both in the article talk pages, and in the Arbitration Committee pages specifically dedicated to serious disputes. We first set up a users typology according to their involvement in conflicts and their publishing and management activity in the encyclopedia. We then used those user types to describe users behavior in contributing to articles that are tagged by the wikipedian community as being in conflict with the official guidelines of Wikipedia, or conversely as being well featured.; Comment: 12 pp