Publicações do ICMC

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Agora exibindo 1 - 15 de 15

Aleijadinho 3D: technology for the preservation and dissemination of cultural heritage.
(2014-05) Rodrigues Junior, José Fernando; Gazziro, Mario Alexandre; Gonçalves, Natália Martins de Oliveira; Neto, Oscar; Fernandes, Yvan; Gimenes, Anayã; Alegre, Caio; Assis, Rômulo de Souza
The "Ajeijadinho 3D" project is an initiative supported by the University of São Paulo (Museum of Science and Dean of Culture and Extension), which involves the 3D digitization of art works of Brazilian sculptor Antonio Francisco Lisboa, better known as Aleijadinho.
Arcabouço computacional para o auxílio do desenvolvimento de rotinas externas C dentro do ambiente SCILAB.
(2008-01) Marco, Anderson Gonçalves; Bruno, Odemir Martinez
Linguagens e ambientes específicos para a computação cientifica, auxiliam o pesquisador em tarefas que envolvem computação e matemática. Entretanto a escrita de rotinas para estas ferramentas e feita em geral utilizando uma linguagem interpretada não apresentando deste modo um desempenhoótimo. O objetivo deste trabalho, é apresentar um arcabouço computacional para favorecer a integração da linguagem C com Scilab (Gomez, 1999), fazendo uma interoperabílidade do ambiente Scilab com o depurador da GNU (GDB). Esta integração permite utilizar os benefícios do ambiente Scilab e o desempenhoda linguagem C.
Combination of techniques to enrich visualization in dentistry.
(2000-12) Minghim, Rosane; Soares, Igor Prata; Oliveira, Maria Cristina Ferreira de; Nonato, Luis Gustavo
This paper reports on the implementation of two diflerent approaches for visualization of dentistry data, discussing their role in providing adequate support for training, exploration, simulation and interaction in Dentistry applications. One of the approaches is a reconstruction technique based on the Delaunay Triangulation, and the other is a Direct Volumetric Rendering and Visualization technique with texture mapping. The results are evaluated in the light of the target applications, which are teaching and training in dentistry, as well as simulation of dental procedures and illnesses. Uses for multiple-technique visualization and exploration are discussed.
Desenvolvimento de um sistema de visualização para neurônios artificiais.
(2002-05) Colturato, Danielle Bentivoglio; Oliveira, Maria Cristina Ferreira de; Valerio Netto, Antonio
Este artigo descreve uma aplicação desenvolvida em colaboração com os pesquisadores do Grupo de Visão Cibernética do IFSC-USP (Instituto de Física de São Carlos-Universidade de São Paulo) que visa apresentar um ambiente interativo para visualização de dados de neurônios gerados por esses usuários, auxiliando dessa forma, o processo de análise dos mesmos. Este sistema permite manipulação dos neurônios por meio de cortes na isosuperticie, escolha de parâmetros (cor,. tipo de técnica de visualização, valor da isosuperficie, etc.). Como ferramenta para auxiliar o desenvolvimento do sistema foi utilizada a biblioteca de classes VTK (The Visualization Toolkit).
A fast projection technique and its applications to visualization of large data sets.
(2010-03) Paulovich, Fernando Vieira; Eler, Danilo M.; Poco, Jorge; Nonato, Luis Gustavo; Botha, Charl P.; Minghim, Rosane
Large multivariate data sets still challenge visualization techniques and their interactive capabilities. In this paper we present a new faster formulation of a high precision projection technique that allows much larger data sets to be handled and interacted with. By using this novel approach, named Piecewise Least Square Projection (P-LSP), we provide new and effective ways of exploring the data set through its feature space. The paper shows the use of P-LSP to help data selection by the user during exploration using coherence amongst data items. Examples are shown for images and for volumes as large as 1,000,000 voxels, with as many as 14 variables per voxel, although the technique can also be used for any data set for which a reasonable feature space can be determined.
Implementing and applying direct volume rendering with textures.
(2000-12) Soares, Igor Prata; Minghim, Rosane; Oliveira, Maria Cristina Ferreira de; Nonato, Luis Gustavo
This paper reports on the implementation of a Direct Volumetric Rendering (DVR) and Visualization techniquein the context of a general-purpose, low cost visualization software with available source code. The technique employs a texture mapping strategy to combine scalar values of volumetric data into three-dimensionalimages. Relevant implementation issues of this technique are presented, and the results are discussed in the light of a target application, namely visualization in dentistry. The technique presented here, DVRT, has demonstrated to behave better than the ray casting DVR technique for the data sets of interest, and also to produce very good results under shading.
Improved visual clustering of large multi-dimensional data sets.
(2003-09) Tejada, Eduardo; Minghim, Rosane
Lowering computational cost of data analysis techniques is an essential step towards including the user in the process and achieving scalability of algorithms for large scale visualization. In this paper we present an improved algorithm for visual clustering of large multi-dimensional data sets. This algorithm is a version with lower computational cost of the IPCLUS algorithm. The original algorithm is an approach that deals efiiciently with multi—dimensionality using various projections of the data in order to perform multi-space clustering, pruning outliers through direct user interaction. The algorithm presented here, named HC-Enhanced, adds a scalability level to the approach without reducing clustering quality. Additionally, an algorithm to improve clusters is added to the approach. A number of test cases is presented with good results.
Método de Hartmann-Shack: noções gerais e aspectos relevantes.
(2002-05) Valerio Netto, Antonio; Oliveira, Maria Cristina Ferreira de
[sem resumo]
On improved projection techniques to support visual exploration of multi-dimensional data sets.
(2003-08) Tejada-Gamero, Eduardo; Minghim, Rosane; Nonato, Luis Gustavo
Projection (or dimensionality reduction) techniques have been used as a means to handling the growing dimensionality of data sets as well as providing a way to visualize information coded into point relationships. Their role is essential in data interpretation and simultaneous use of different projections and their visualizations improve data understandingand increase the level of confidence in the result. For that purpose projections should be fast to allow multiple views of the same data set. In this work we present a novel fast technique for projecting multi-dimensional data sets into bidimensional (2D) spaces that preserves neighborhood relationships. Additionally, a new technique for improving 2D projections from multi-dimensiona] data is presented, that helps reduce the inherent loss of information yielded by dimensionality reduction. The results are stimulating and are presented in the form of comparative visualizations against known and new 2D projection techniques. Based on the projection improvement approach presented here, a new metric for quality of projection is also given, that matches well the visual perception of quality. We discuss the implication of using improved projections in visual exploration of large data sets and the role of interaction in visualization of projected subspaces.
On improved projection techniques to support visual exploration of multi-dimensional data sets.
(2003) Tejada-Gamero, Eduardo; Minghim, Rosane; Nonato, Luis Gustavo
Projection (or dimensionionality reduction) techniques have been used as a means to handling the growing dimensionality of data sets as well as providing a way to visualize information coded into point relationships. Their role is essential in data interpretation and simultaneous use of different projections and their visualizations improve data understanding and increase the level of confidence in the result. For that purpose projections should be fast to allow multiple views of the same data set. In this work we present a novel fast technique for projecting multi-dimensional data sets into bidimensional (2D) spaces that preserves neighborhood relationships. Additionally, a new technique for improving 2D projections from multi-dimensional data is presented, that helps reduce the inherent loss of information yielded by dimensionality reduction. The results are stimulating and are presented in the form of comparative visualizations against known and new 2D projection techniques. Based on the projection improvement approach presented here, a new metric for quality of projection is also given, that matches well the visual perception of quality. We discuss the implication of using improved projections in visual exploration of large data sets and the role of interaction in visualization of projected subspaces.
Properties of the unary similarity operator integrated to the relational algebra.
(2008) Ferreira, Mônica Ribeiro Porto; Traina Junior, Caetano; Traina, Agma Juci Machado; Dias, Ires
Conventional operators for data comparison are either based on exact matching or on total order relationship among elements. Neither of them are appropriate to manage complex data, such as multimedia data (e.g., images, audio and large texts), time series and genetic sequences. In fact, the most meaningful way to compare complex data is by similarity. However, the Relational Algebra, employed in the relational Database Management Systems (RDBMS), cannot express similarity criteria. In order to address this support, an extension to the Relational Algebra is under development at GBdI-ICMCUSP (Databases and Images Group), aiming to represent similarity queries in algebraic expressions. This technical report defines a formal framework which embodies the unary similarity operators into Relational Algebra, and precisely define their algebraic properties when used in query expressions either alone or combined with the existing exact matching and relational operators. We also show how to take advantage of such properties to optimize queries that include similarity operators, presenting a similarity query optimizer developed for SIREN (the Similarity Retrieval Engine), which uses a existing RDBMS to answer similarity queries.
Rule-based topic mining to assist user-centered visual exploration of document collections.
(2009-06) Pinho, Roberto; Oliveira, Maria Cristina Ferreira de; Minghim, Rosane; Lopes, Alneu de Andrade; Rodrigues, Renato
We propose a three step iterative and interactive visual text mining process to assist users in exploring document collections. In the proposed approach (i) topics are automatically extracted from a document collection , (ii) users explore a similarity-based document map and its related topics, while refining a topic list, and (iii) map quality itself and topic list definition can both be improved based on user interaction. A selective and sequential covering association rule induction strategy is employed to extract the topics. In this strategy, association rules are sequentially induced from selected (manually or automatically) groupings in the similarity-based document maps. Resulting topics are displayed on a Topic Tree control window that assists users in exploring the collection by (i) identifying documents related to specific topics in the map, (ii) removing uninteresting documents from the map, based on their topics, (iii) comparing related topics and documents, (iv) extracting new topics from user selected map regions or from the entire map, (v) building derived maps, and, (vi) eventually exporting sets of labeled documents. Derived maps inherit the previous topic definitions, while benefiting from the removal of undesired documents and, optionally, from the use of terms descriptive of relevant topics to compute document similarity. We present two case studies – on an online news corpus and on a collection of scientific papers – to illustrate our process and its suitability to explore document collections.
Seamlessly integrating similarity queries in SQL.
(2006-07) Barioni, Maria Camila N.; Razente, Humberto; Traina, Agma Juci Machado; Traina Junior, Caetano
Similarity search has received great attention on modern database applications involving complex objects, since the queries over such objects are seldom based on exact matches, but rather on some notion of similarity, specific to each domain. However, the SQL query language does not provide support for similarity queries. This paper proposes to include similarity queries to SQL, adding a powerful set of similarity operators. Two kinds of complex objects are considered: those monolithically stored as Binary Large Objects, and those stored as sets of attributes in a relation. Concerning monolithic objects, we regard specificallysimilarity search in image datasets. The paper also proposes ways to efficiently store and retrieve complex objects, showing a prototype developed to validate the concepts and the syntax presented.
Visualization of music collections based on structural similarity.
(2014-03) Soriano, Aurea; Paulovich, Fernando Vieira; Nonato, Luis Gustavo; Oliveira, Maria Cristina Ferreira de
Users interact a lot with their personal music collections, typically using standard text-based interfaces that offer constrained functionalities based on assigned metadata or tags.
VoS: uma nova proposta de rendering volumétrico híbrido.
(2003-07) Cateriano, Patricia Shirley Herrera; Nonato, Luis Gustavo
Esse trabalho de mestrado propõe um novo método de rendering volumétrico híbrido. Essa nova proposta. chamada Vos, mapeia a informação contida no interior do modelo sobre a superfície de bordo, possibilitando um rendering de superfície sem a perda da infomação volumétrica, fato ainda não descrito na literatura.Além disso, a técnica pode ser aplicada em decomposições celulares não estruturadas, como malhas tetraedrais por exemplo. Um levantamento sobre as principais técnicas de rendering híbrido descritas na literatura. juntamente com uma proposta de classificação para tais técnicas, também fazem parte desse trabalho.

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