1997

[DCA97-01]  Efficient Visualization in a Mobile WWW Environment

Alberto B. Raposo, Luc Neumann, Léo P. Magalhães, Ivan L. M. Ricarte

Abstract: The facility of access to information in the World-Wide Web (WWW), the expanding availability of information technology, and the recent developments in the handling of multimedia data are all important steps towards a Global Information Infrastructure accessible to anyone, anywhere in the world. However, in order to achieve this accessible infrastructure, one should consider the aspects related to efficient communication. Some of these aspects are addressed in this work. A mobile WWW rendering application using VRML is introduced, the related problems are pinpointed, and approaches to overcome them are proposed. As a first result we have developed an application that filters VRML scenes to render only parts selected by the user.

Keywords: World-Wide Web Application, Mobile Computing, VRML, Resource Adaptive Distribution

[DCA97-02]  Uma ferramenta cinemática para animação

Alberto B. Raposo, Léo P. Magalhães

Abstract: This report presents the lower level language of the TOOKIMA (TOOl KIt for scripting computer Modeled Animation). This language is an extension of C (a library of functions, macros, etc) and, on top of it, a higher level scripting language and a graphical user interface have been built.

Keywords: Computer Modeled Animation, Animation Scripting Language

[DCA97-03]  Uma Linguagem para Desenvolvimento de Roteiros de Animação

Alberto B. Raposo, Léo P. Magalhães

Abstract: This report presents the language for the development of animation scripts in the TOOKIMA 2.0 (TOOl KIt for scripting computer Modeled Animation). The proposed language intends to be intermediary between the complex language of the TOOKIMA (similar to C) and the graphical interface (whose objective is to enable the interactive construction of the script).
The new language enables the development of scripts in a higher level of commands (closer to that developed by animation professionals). This eliminates the need of the knowledge about the lower level commands of TOOKIMA's language. Although simple, this new scripting language is complete enough to allow the use of all important resources that already exist in the TOOKIMA.

Keywords: Computer Modeled Animation, Scripting Languages

[DCA97-04]  Frequency Reponse Design of Fuzzy Controller

Carlos Pinheiro, Fernando Gomide

[DCA97-05]  Using Petri Nets for Animation Modeling and Analysis

Alberto B. Raposo, Léo P. Magalhães

Abstract: This paper presents the use of Petri Nets for animation modeling and analysis. At first some traditional approaches for animation modeling are discussed. Then the use of Petri Nets in an animation environment is presented. For the sake of simplicity the paper does not explore the theorethical side of the methodology, believing examples are the most appropriate way to introduce this new tool for animation modeling. Two examples show some of the possibilities offered by the methodology.

Keywords: Computer Modeled Animation, Animation Control, Petri Nets

[DCA97-06]  An extensible interactive image synthesis environment

Wu-Shin Ting, Marcelo de Gomensoro Malheiros, Johannes R. Behr, Jorge Alberto Diz

Abstract: Under image synthesis we understand not only the transformation of models into imagery but also a process that involves the capture and the modeling of the intentions of a user. Depending on the required image quality, this process might demand several specialized tasks, such as geometric modeling, lighting modeling and image processing. Each of these tasks, in their turn, might provide a graphical interactive interface to facilitate the data enhancements. There is a variety of commercial and academic stand-alone interactive synthesis systems. However, none of them embraces all existing technologies. To explore the individual qualities of each system, a variety of data format converters is written and the users are responsible for the co-working of these systems. This report shows a framework for an extensible interactive image synthesis environment. It is an attempt to overcome the integration problem that proprietary application developers usually face. The basic idea is that any component application related to the image synthesis can be added to this environment with little effort, in order to enrich its functionalities gradually. Furthermore, these applications can communicate to each other for mutual benefits. We adopt an object-oriented approach. An object is an independently developed application, which is responsible for maintaining and manipulating its problem-domain data. If the application is an interactive one, it is also responsible for the displaying of these data. We consider in this report that this object is integrated in the proposed environment, if its problem-domain data is transparently accessible by other applications and it can request services available in the environment to perform any specific task. On the regard of the existing technologies, it is also presented some guidelines for the implementation of the proposed environment. We show that there already exist technological solutions for three crucial points in the proposed environment - 3D graphics, 3D information carrier among the applications and basic integrating mechanisms. The question is how to combine them appropriately to achieve the desired performance.

Keywords: Extensible Environment, Image Synthesis, Object-Oriented Framework, Distributed System

[DCA97-07]  Algoritmos sequenciais de ordenação interna

Anna Catharina da Costa Dantas, Ivan Luiz Marques Ricarte

[DCA97-08]  Controle natural de velocidade ou conjugado para motores de indução trifásicos

Márcio Luiz de Andrade Netto, Fernado José von Zuben, Flávio de Melo Pereira

[DCA97-09]  Computational semiotics: An approach for the study of intelligent systems

Fernando A. C. Gomide, Ricardo Ribeiro Gudwin

[DCA97-10]  Deformação de superfícies não-rígidas: implementação e análise

Wu-Shin Ting, Paulo F. da Santa Clara Ramos Jr, Agnus Azevedo Horta

Abstract: The deformable model proposed by Terzopoulos et al. is founded on the motion equation in Lagrangean form and adjust the elastic deformation by parameters related to the metric and curvature tensors of surfaces. Since it unifies the description of shape and motion, this model significantly simplifies the approach of animation of complex objects. The flexibility and the modeling power of this model is recognized by the modeling community. Several subsequent works are made to improve this approach. Two problems, which were not enough discussed, is how to manipulate the parameters to get realistic dynamics behavior and its application domains. This work addresses these problems. Using concepts from Differential Geometry, we could identify the relevant simplifications on the physically-based models to derive the deformable model proposed by Terzopoulos et al. Then, we took advantages of the geometric potential of this model and deal more intuitively with parameters in order to get realistic simulation or physical movements through an intuitive interface. A major challenge that we faced was the non-independency between these parameters. This interdependency, which is a consequence of the differential relation between the metric and the curvature tensors, is not considered up to now, and, as we could see, it can yield non-realistic deformations. In our analysis we deal more specifically with the class of surfaces with a big resistance against stretching and little resistance against curvature. These features would allow us to simulate the behavior of a great variety of physical objects, like a piece of cloth or a sheet of paper.

Keywords: Deformable Models, Differential Geometry, Goemetric Modeling, Animation.

[DCA97-11]  Tookima 2.0 - An Interactive Animation System

Alberto B. Raposo, Léo P. Magalhães, Clarisse Sieckenius de Souza, José Tarcísio Franco de Camargo, Fernando José Lamanna

Abstract: The production of computer animation without the presence of a programmer requires unobtrusive task-centered interaction between user and system. This paper presents TOOKIMA 2.0 (a Tool Kit for scripting computer Modelled Animation), an interactive scripting environment for describing kinematic computer-modelled animations. It supports the production of animation at two distinct levels of abstraction. In the lower level, users create animations by writing scripts as a specialized language. In the upper level, users can generate scripts interactively, without knowing the underlying scripting language.The environment is designed so as to introduce basic notions of programming in the upper level, and thus to lead users into acquiring basic programming skills needed for operation in the lower level.

Keywords: Computer Modeled Animation, End-User Programming, Graphical User Interfaces

[DCA97-12]  Categorização de modelos disponíveis no mapa de categorização abstrata

Carlos Miguel Tobar Toledo, Ivan Luiz Marques Ricarte

Abstract: Neste relatório técnico são apresentadas algumas caracterizações sobre a existência e o nível de abstração de mecanismos disponíveis em modelos de dados utilizados para projetos de aplicações com hipermídia. Considera-se para isso o mapa de categorização abstrata, que no seu nível externo (mais alto de abstração) abrange um conjunto de aspectos para especificação de dados, definido através da visão-T. Tanto o mapa de categorização abstrata quanto a visão-T são descritos em outro lugar.

Keywords: data models, hypermedia, data navigational model, abstract categorization map, T-vision

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[DCA97-13]  Avaliação de algoritmos sequenciais de ordenação interna

Anna Catharina da Costa Dantas, Ivan Luiz Marques Ricarte