Gao Shuming

Virtual grasping for virtual assembly tasks

Intuitive and natural interactions are key aspects of virtual assembly applications. In this paper, we present intuitive virtual hand interactions with parts, subassemblies and tools. Grasping patterns are developed based on the abstraction of various mechanic shapes, kinematics model of virtual hand is built upon the anatomic structure of the human hand to guarantee motion realism, and real-time collision detection scheme is used to identify whether the current finger configuration matches a specific grasping pattern. Experiments on assembly models with a CyberGlove dataglove show that our virtual grasping scheme works well for virtual assembly tasks.

Partial Relevance Feedback for 3D Model Retrieval

Relevance feedback (RF) proved an effect way to improve the precision and recall of 3D model retrieval. Unfortunately, through existing methods of RF, it is straightforward to find out whether a model is similar or not, but it is impossible to find out which local part is similar or not. The new partial method of RF proposed in this paper provides a good solution, in which not only the similar models are marked out but also the local parts which are similar or not are pointed out and taken advantage at the same time. This additional information contributes a lot to the improvement of 3D retrieval. Experiments show superiority in effectivity of the new method.

A CSCW-based interpreting system of remote sensing imagery

Along with the great advancement of remote sensing technology and extensive application of remote sensing information, more and more requirements on capability and efficiency for all kinds of interpreting system of remote sending images come out. The conventional interpreting systems commonly have the operating mode with one single interpreter and an isolated computer. But this conventional mode has a serious immanent limitation due to the isolation of position, personnel, data, software, hardware and so on. This paper provides a CSCW-based interpreting system of remote sensing imagery (RSI) to avoid the limitation from the conventional systems. This new system fully integrates the remote sensing technology and computer supported cooperative work (CSCW) technology, actualizes interpreting of RSI with a synchronized operation for multi-user. Consequently it greatly improves capability, efficiency, and accuracy. The better actual effect proves that interpreting system of RSI is feasible and effective.

Mask synthesis and verification based on geometric model for surface micro-machined MEMS

Traditional MEMS (microelectromechanical system) design methodology is not a structured method and has become an obstacle for MEMS creative design. In this paper, a novel method of mask synthesis and verification for surface micro-machined MEMS is proposed, which is based on the geometric model of a MEMS device. The, emphasis is focused on synthesizing the masks at the basis of the layer model generated from the geometric model of the MEMS device. The method is comprised of several steps; the correction of the layer model, the generation of initial masks and final masks including multi-layer etch masks, and mask simulation. Finally some test results are given.

A mathematical model of symmetry based on mathematical definition

Tolerance is imperative for seamless integration of CAD/CAM (Computer Aided Disign/Computer Aided Manufacture) which is just a text attribute and has no semantics in present CAD systems. There are many tolerance types, the relations between which are very complicated. In addition, the different principles of tolerance make study of tolerance difficult; and there may be various meanings or interpretation for the same type of tolerance because of the literal definition. In this work, latest unambiguous mathematical definition was applied to study, explain and clarfy: (1) the formation and representation of tolerance zone, and (2) the formation and representation of variational elements; after which, the mathematical models of symmetry of different tolerance principles and different interpretations were derived. An example is given to illustrate the application of these models in tolerance analysis.

Hierarchical geometric constraint model for parametric feature based modeling

A new geometric constraint model is described, which is hierarchical and suitable for parametric feature based modeling. In this model, different levels of geometric information are represented to support various stages of a design process. An efficient approach to parametric feature based modeling is also presented, adopting the high level geometric constraint model. The low level geometric model such as B-reps can be derived automatically from the high level geometric constraint model, enabling designers to perform their task of detailed design.