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Rastreamento de componentes conexas em vídeo 3D para obtenção de estruturas tridimensionais; Tracking of connected components from 3D video in order to obtain tridimensional structures

Pires, David da Silva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/08/2007 Português
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Este documento apresenta uma dissertação sobre o desenvolvimento de um sistema de integração de dados para geração de estruturas tridimensionais a partir de vídeo 3D. O trabalho envolve a extensão de um sistema de vídeo 3D em tempo real proposto recentemente. Esse sistema, constituído por projetor e câmera, obtém imagens de profundidade de objetos por meio da projeção de slides com um padrão de faixas coloridas. Tal procedimento permite a obtenção, em tempo real, tanto do modelo 2,5 D dos objetos quanto da textura dos mesmos, segundo uma técnica denominada luz estruturada. Os dados são capturados a uma taxa de 30 quadros por segundo e possuem alta qualidade: resoluções de 640 x 480 pixeis para a textura e de 90 x 240 pontos (em média) para a geometria. A extensão que essa dissertação propõe visa obter o modelo tridimensional dos objetos presentes em uma cena por meio do registro dos dados (textura e geometria) dos diversos quadros amostrados. Assim, o presente trabalho é um passo intermediário de um projeto maior, no qual pretende-se fazer a reconstrução dos modelos por completo, bastando para isso apenas algumas imagens obtidas a partir de diferentes pontos de observação. Tal reconstrução deverá diminuir a incidência de pontos de oclusão (bastante comuns nos resultados originais) de modo a permitir a adaptação de todo o sistema para objetos móveis e deformáveis...

Duas abordagens para casamento de padrões de pontos usando relações espaciais e casamento entre grafos; Two approaches for point set matching using spatial relations for graph matching

Noma, Alexandre
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 07/07/2010 Português
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Casamento de padrões de pontos é um problema fundamental em reconhecimento de padrões. O objetivo é encontrar uma correspondência entre dois conjuntos de pontos, associados a características relevantes de objetos ou entidades, mapeando os pontos de um conjunto no outro. Este problema está associado a muitas aplicações, como por exemplo, reconhecimento de objetos baseado em modelos, imagens estéreo, registro de imagens, biometria, entre outros. Para encontrar um mapeamento, os objetos são codificados por representações abstratas, codificando as características relevantes consideradas na comparação entre pares de objetos. Neste trabalho, objetos são representados por grafos, codificando tanto as características `locais' quanto as relações espaciais entre estas características. A comparação entre objetos é guiada por uma formulação de atribuição quadrática, que é um problema NP-difícil. Para estimar uma solução, duas técnicas de casamento entre grafos são propostas: uma baseada em grafos auxiliares, chamados de grafos deformados; e outra baseada em representações `esparsas', campos aleatórios de Markov e propagação de crenças. Devido as suas respectivas limitações, as abordagens são adequadas para situações específicas...

Comparação entre uma solução combinatória e um método de planos-de-corte para o problema do emparelhamento de peso máximo; Comparison between a combinatorial solution and plane-cut method for the maximum weight matching problem.

Oliveira, Ander Conselvan de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 10/12/2010 Português
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Um emparelhamento em um grafo é um conjunto de arestas duas a duas não adjacentes. Dado um grafo G com pesos em suas arestas, o problema do emparelhamento de peso é máximo é encontrar um emparelhamento cuja soma dos pesos de suas arestas é máxima. Neste trabalho estudamos diferentes soluções para esse problema. Estudamos algoritmos combinatórios que resolvem o problema no caso em que G é bipartido e no caso geral. O algoritmo de Edmonds é um algoritmo polinomial cuja complexidade de tempo é O(n^4), onde n é o número de vértices do grafo G. Discutimos nesse trabalho nossa implementação desse algoritmo. Num trabalho de 1985, Grötschel e Holland propuseram o uso de ferramentas de programação linear para resolver o mesmo problema. O método chamado de planos-de-corte baseia-se em um resultado de Padberg e Rao de que o problema da separação associado ao poliedro dos emparelhamentos pode ser resolvido em tempo polinomial. Neste trabalho fizemos implementações dos dois métodos e os utilizamos para resolver diversos tipos de instâncias do problema. Nossa conclusão é que o método poliédrico, apesar de utilizar ferramentas genéricas, é bastante eficiente na prática.; A matching in a graph G is a set of pairwise disjoint edges of G. Given a graph G with edge weights...

Uma proposta para análise de similaridade entre documentos XML e ontologias definidas em OWL; A proposal to evaluate the similarity between XML documents and ontologies specified in OWL

Noll, Rodrigo Perozzo
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf
Português
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O casamento de documentos e esquemas é aplicável em diversos cenários, como integração de dados, data warehouse, e processamento semântico de consultas. A maioria das propostas baseia-se na similaridade léxica ou semântica entre as representações. No entanto, existem poucas propostas para casamento de documentos XML e ontologias e, na maioria das vezes, exigem intervenção de um especialista. Neste contexto, o trabalho aqui apresentado objetiva propor uma estrutura que identifique o grau de similaridade entre estruturas definidas em XML e ontologias, considerando perspectivas léxicas e semânticas. Para tanto, foram avaliadas propostas encontradas na literatura para análise de similaridade entre esquemas, considerando ambas as perspectivas, visando identificar padrões e melhores práticas. Posteriormente, integraram-se estes padrões e boas práticas para avaliar a viabilidade prática da proposta. Com base no resultado da análise de viabilidade, desenvolveu-se um estudo de caso que avaliou os resultados obtidos. A principal contribuição deste trabalho diz respeito à automatização da avaliação de similaridade, possibilitando definir qual modelagem conceitual (ontologia) melhor descreve um documento XML.; Document and schema matching is relevant in many scenarios...

Matching objects without language extension

Visser, J.
Fonte: ETH Swiss Federal Institute of Technology Publicador: ETH Swiss Federal Institute of Technology
Tipo: Artigo de Revista Científica
Publicado em /11/2006 Português
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Pattern matching is a powerful programming concept which has proven its merits in declarative programming. The absence of pattern-matching in object-oriented programming languages is felt especially when tackling source code processing problems. But existing proposals for pattern matching in such languages rely on language extension, which makes their adoption overly intrusive. We propose an approach to support pattern matching in mainstream object-oriented languages without language extension. In this approach, a pattern is a first-class entity, which can be created, be passed as argument, and receive method invocations, just like any other object. We demonstrate how our approach can be used in conjunction with existing parser generators to perform pattern matching on various kinds of abstract syntax representation. We elaborate our approach to include concrete syntax patterns, and mixing of patterns and visitors for the construction of sophisticated syntax tree traversals.

Subword segmentation--leveling out morphological variations for medical document retrieval.

Hahn, U.; Honeck, M.; Piotrowski, M.; Schulz, S.
Fonte: American Medical Informatics Association Publicador: American Medical Informatics Association
Tipo: Artigo de Revista Científica
Publicado em //2001 Português
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Many lexical items from medical sublanguages exhibit a complex morphological structure that is hard to account for by simple string matching (e.g., truncation). While inflection is usually easy to deal with, productive morphological processes in terms of derivation and (single-word) composition constitute a real challenge. We here propose an approach in which morphologically complex word forms are segmented into medically significant subwords. After segmentation, both query terms and document terms are submitted to the matching procedure. This way, problems arising from morphologically motivated word form alterations can be eliminated from the retrieval procedure. We provide empirical data which reveals that subword-based indexing and retrieval performs significantly better than conventional string matching approaches.

Strategy-Proofness Versus Efficiency in Matching with Indifferences: Redesigning the NYC High School Match

Abdulkadiroglu, Atila; Pathak, Parag Abishek; Roth, Alvin E.
Fonte: American Economic Association Publicador: American Economic Association
Tipo: Artigo de Revista Científica
Português
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The design of the New York City (NYC) high school match involved trade-offs among efficiency, stability, and strategy-proofness that raise new theoretical questions. We analyze a model with indifferences -- ties -- in school preferences. Simulations with field data and the theory favor breaking indifferences the same way at every school -- single tiebreaking -- in a student-proposing deferred acceptance mechanism. Any inefficiency associated with a realized tiebreaking cannot be removed without harming student incentives. Finally, we empirically document the extent of potential efficiency loss associated with strategy-proofness and stability, and direct attention to some open questions. (JEL C78, D82, I21); Economics

The Lymphocyte Pattern Matching Engine

Miller, Bradford W.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
Português
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This document describes a new pattern matching engine used as part of the discourse reasoning components in the TRAINS-96 system. Its dominant characteristics are simplicity, efficiency, and an economical model for driving the search engine.

The design and implementation of a parallel document retrieval engine

Hawking, David
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 263051 bytes; 356 bytes; application/pdf; application/octet-stream
Português
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Document retrieval as traditionally formulated is an inherently parallel task because the document collection can be divided into N sub-collections each of which may be searched independently. Document retrieval software can potentially exploit the power and capacity of a large-scale parallel machine to improve speed, to extend the size of the largest collection which can be processed, to respond quickly to changes in the document collection and/or to increase the power and expressivity of the retrieval query language. This paper includes discussion of the issues involved in the design of a practical parallel document retrieval engine for a distributed-memory multicomputer and a description of the implementation of PADRE, a retrieval engine for the Fujitsu AP1000. Performance results are presented and scope of applicability of the techniques is discussed.; no

On Knowledge-poor Methods for Person Name Matching and Lemmatization for Highly Inflectional Languages

PISKORSKI Jakub; WIELOCH Karol; SYDOW Marcin
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Articles in Journals Formato: Printed
Português
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Web person search is one of the most common activities of Internet users. Recently, a vast amount of work on applying various NLP techniques for person name disambiguation in large web document collections has been reported, where the main focus was on English and few other major languages. This article reports on knowledge-poor methods for tackling person name matching and lemmatization in Polish, a highly inflectional language with complex person name declension paradigm. These methods apply mainly well-established string distance metrics, some new variants thereof, automatically acquired simple suffix-based lemmatization patterns and some combinations of the aforementioned techniques. Furthermore, we also carried out some initial experiments on deploying techniques that utilize the context, in which person names appear. Results of numerous experiments are presented. The evaluation carried out on a data set extracted from a corpus of on-line news articles revealed that achieving lemmatization accuracy figures greater than 90% seems to be difficult, whereas combining string distance metrics with suffix-based patterns results in 97,6-99% accuracy for the name matching task. Interestingly, no significant additional gain could be achieved through integrating some basic techniques...

Classification of scientific publications according to library controlled vocabularies: a new concept matching-based approach

Joorabchi, Arash; Mahdi, Abdulhussain E
Fonte: Emerald Publicador: Emerald
Tipo: info:eu-repo/semantics/pre-print; all_ul_research; ul_published_reviewed
Português
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peer-reviewed; Purpose - This paper aims to report on the design and development of a new approach for automatic classification and subject indexing of research documents in scientific digital libraries and repositories (DLR) according to library controlled vocabularies such as DDC and FAST.Design/methodology/approach - The proposed concept matching-based approach (CMA) detects key Wikipedia concepts occurring in a document and searches the OPACs of conventional libraries via querying the WorldCat database to retrieve a set of MARC records which share one or more of the detected key concepts. Then the semantic similarity of each retrieved MARC record to the document is measured and, using an inference algorithm, the DDC classes and FAST subjects of those MARC records which have the highest similarity to the document are assigned to it.Findings - The performance of the proposed method in terms of the accuracy of the DDC classes and FAST subjects automatically assigned to a set of research documents is evaluated using standard information retrieval measures of precision, recall, and F1. The authors demonstrate the superiority of the proposed approach in terms of accuracy performance in comparison to a similar system currently deployed in a large scale scientific search engine.Originality/value - The proposed approach enables the development of a new type of subject classification system for DLR...

A Theory of Information Matching

Gorla, Jagadeesh; Robertson, Stephen; Wang, Jun; Jambor, Tamas
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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In this work, we propose a theory for information matching. It is motivated by the observation that retrieval is about the relevance matching between two sets of properties (features), namely, the information need representation and information item representation. However, many probabilistic retrieval models rely on fixing one representation and optimizing the other (e.g. fixing the single information need and tuning the document) but not both. Therefore, it is difficult to use the available related information on both the document and the query at the same time in calculating the probability of relevance. In this paper, we address the problem by hypothesizing the relevance as a logical relationship between the two sets of properties; the relationship is defined on two separate mappings between these properties. By using the hypothesis we develop a unified probabilistic relevance model which is capable of using all the available information. We validate the proposed theory by formulating and developing probabilistic relevance ranking functions for both ad-hoc text retrieval and collaborative filtering. Our derivation in text retrieval illustrates the use of the theory in the situation where no relevance information is available. In collaborative filtering...

Cross-Document Pattern Matching

Kucherov, Gregory; Nekrich, Yakov; Starikovskaya, Tatiana
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/02/2012 Português
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We study a new variant of the string matching problem called cross-document string matching, which is the problem of indexing a collection of documents to support an efficient search for a pattern in a selected document, where the pattern itself is a substring of another document. Several variants of this problem are considered, and efficient linear-space solutions are proposed with query time bounds that either do not depend at all on the pattern size or depend on it in a very limited way (doubly logarithmic). As a side result, we propose an improved solution to the weighted level ancestor problem.

Multi-document Summarization by Graph Search and Matching

Mani, Inderjeet; Bloedorn, Eric
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/12/1997 Português
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We describe a new method for summarizing similarities and differences in a pair of related documents using a graph representation for text. Concepts denoted by words, phrases, and proper names in the document are represented positionally as nodes in the graph along with edges corresponding to semantic relations between items. Given a perspective in terms of which the pair of documents is to be summarized, the algorithm first uses a spreading activation technique to discover, in each document, nodes semantically related to the topic. The activated graphs of each document are then matched to yield a graph corresponding to similarities and differences between the pair, which is rendered in natural language. An evaluation of these techniques has been carried out.; Comment: 7 pages, 5 Postscript figures, uses aaai.sty

Unique Pattern Matching in Strings

Vansummeren, Stijn
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/02/2003 Português
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Regular expression patterns are a key feature of document processing languages like Perl and XDuce. It is in this context that the first and longest match policies have been proposed to disambiguate the pattern matching process. We formally define a matching semantics with these policies and show that the generally accepted method of simulating longest match by first match and recursion is incorrect. We continue by solving the associated type inference problem, which consists in calculating for every subexpression the set of words the subexpression can still match when these policies are in effect, and show how this algorithm can be used to efficiently implement the matching process.; Comment: 22 pages

Manifold Matching: Joint Optimization of Fidelity and Commensurability

Priebe, Carey E.; Marchette, David J.; Ma, Zhiliang; Adali, Sancar
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 22/12/2011 Português
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Fusion and inference from multiple and massive disparate data sources - the requirement for our most challenging data analysis problems and the goal of our most ambitious statistical pattern recognition methodologies - -has many and varied aspects which are currently the target of intense research and development. One aspect of the overall challenge is manifold matching - identifying embeddings of multiple disparate data spaces into the same low-dimensional space where joint inference can be pursued. We investigate this manifold matching task from the perspective of jointly optimizing the fidelity of the embeddings and their commensurability with one another, with a specific statistical inference exploitation task in mind. Our results demonstrate when and why our joint optimization methodology is superior to either version of separate optimization. The methodology is illustrated with simulations and an application in document matching.; Comment: 22 pages, 12 figures

SA_MetaMatch: Relevant document discovery through document metadata and indexing

Yau, Hiu; Hawker, J. Scott
Fonte: Association for Computing Machinery (ACM) Publicador: Association for Computing Machinery (ACM)
Tipo: Proceedings
Português
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SA_MetaMatch, a component of the Standards Advisor (SA), is designed to find relevant documents through matching indices of metadata and document content. The elements in the metadata schema are mainly adopted from the Dublin Core (DC). The implementation of the XML metadata schema and coding follows the DC recommended guidelines. After metadata is generated manually for an unstructured document, or is extracted automatically from documents of well defined layout, they are stored in metadata files or in a repository. The indices of the descriptive metadata elements and that of the document content are generated. They are searched and compared to find related documents, based on our observation that if the metadata and high frequency index words of document content are related, then the corresponding documents are likely to be related as well. A ranked list of possible relevant documents is returned as the result. Several matching algorithms have been explored. We selected a sum of word-scored approach which not only gives relevant scores for the matched documents, but also gives an individual score for each of the matching words which provide hints for domain experts to grasp the concepts in the documents.; 2004 ACM Southeast conference proceedings. This is a digitized copy derived from an ACM-copyrighted work. ACM did not prepare this copy and does not guarantee that it is an accurate copy of the originally published work.

Document understanding system using stochastic context-free grammars

Handley, John; Namboodiri, Anoop; Zanibbi, Richard
Fonte: IEEE Computer Society : Eighth International Conference on Document Analysis and Recognition Publicador: IEEE Computer Society : Eighth International Conference on Document Analysis and Recognition
Tipo: Proceedings
Português
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We present a document understanding system in which the arrangement of lines of text and block separators within a document are modeled by stochastic context free grammars. A grammar corresponds to a document genre; our system may be adapted to a new genre simply by replacing the input grammar. The system incorporates an optical character recognition system that outputs characters, their positions and font sizes. These features are combined to form a document representation of lines of text and separators. Lines of text are labeled as tokens using regular expression matching. The maximum likelihood parse of this stream of tokens and separators yields a functional labeling of the document lines. We describe business card and business letter applications.; "The Recognition Strategy Language," Eighth International Conference on Document Analysis and Recognition. Held at Seoul, South Korea: 29 August - 1 September 2005. ©2005 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

Recognition-free Retrieval of Old Arabic Document Images

Sari,Toufik; Kefali,Abderrahmane
Fonte: Centro de Investigación en computación, IPN Publicador: Centro de Investigación en computación, IPN
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 Português
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Searching of old document images is a relevant issue today. In this paper, we tackle the problem of old Arabic document images retrieval which form a good part of our heritage and possess an inestimable scientific and cultural richness. We propose an approach for indexing and searching degraded document images without recognizing the textual patterns in order to avoid the high cost and the difficult effort of the optical character recognition (OCR). Our basic idea consists in casting the problem of document images retrieval from the field of document analysis to the field of information retrieval. Thus, we can combine symbolic notation and semic representation and exploit techniques from the two fields, in particular, the techniques of suffix trees and approximate string matching. Each document of the collection is assigned an ASCII file of word codes. Words are represented by their topological features, namely, ascenders, descenders, etc. So, instead of searching in the image, we look for word codes in the corresponding file code. The tests performed on two types of documents, Arabic historical documents and Algerian postal envelopes, have showed good performance of the proposed approach.

Color Matching using Time Series Searching in Color Databases

Felipe Riverón,E. M.; Figueroa Nazuno,J. G.; Gutiérrez Tornés,A. F.; Barrón Fernández,R; Cervantes Alarcón,F. I.
Fonte: Centro de Investigación en computación, IPN Publicador: Centro de Investigación en computación, IPN
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2008 Português
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The goal of this paper is to document the use of time series in color matching. Although time series are not commonly used for this purpose, the results obtained, based on the principle of similarity in time series using the Euclidean distance, establish the validity of its use for color matching applications. The accuracy of color matching was based on the measures of reflectivity versus wavelength of samples given by a spectrophotometer. The error estimation was calculated using a database of 1001 elements. The matching module has been tested with six samples included and not included in the database. All of them gave an error lower than the estimated absolute error of 11.36.