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A new technology that has been used to construct virtual environments in the computer, where objects behave as if they were real ones, has been drawing attention. This paper studies virtual manipulation of elastic objects as a fundamental example of nonrigid materials. An elastic object modeled by a combination of material points and springs can be deformed with a rigid cylindrical manipulator controlled by a mouse in imitation of actual actions such as hitting or thrusting. The dynamic response of the elastic object in a collision with the manipulator is generated by a numerical method of solution based on physics and is displayed in real time. An improved spring model is presented in which the amplitude is restricted by elastic energy when the elastic object receives extensive external force. The results of implementation show the effectiveness of the spring model and interactivity of the system. © 1998 Scripta Technica. Electron Comm Jpn Pt 3, 81(4): 42–50, 1998 [ABSTRACT FROM AUTHOR]

This paper presents a systematic discussion of the relationship between classical multivariate analysis and various data compression methods arising from the none linear mapping capability of multilayer neural networks. The important points of a geometrical interpretation for the case of four or more layers are set down using the well known autoassociation model and the pulse-input/ pattern-output network (PPN) model proposed by the authors. Next, the previously unused four-layer autoassociative model is investigated and its effectiveness is demonstrated. Then, the four-layer autoassociative map- ping model and the four-layer PPN are compared using a method based on multivariate analysis. That is, it is shown that each method can be related in an approximate fashion to piecewise-linear data compression models as well as to factor analysis models. Finally, to back up these studies, several example experiments are described; a five-layer autoassociative mapping model is then examined, and the data compression capabilities of all three models are compared. [ABSTRACT FROM AUTHOR]

A virtual manipulation system for origami (paper folding) is described. A piece of paper defined in a computer can be deformed interactively by picking and moving a corner vertex of a paper face on a graphic screen using a mouse. Three kinds of folding operations and a curving operation transform the paper into a three-dimensional figure made of flat or curved surfaces. The roundness of the curved surfaces is calculated in real-time by minimizing an elastic energy function. The simulated paper bas traditional Japanese decoration applied as a texture to give a more realistic appearance. It is rendered with shading in real-time. [ABSTRACT FROM AUTHOR]