Symbolic bisimulation avoids the infinite branching problem causedby instantiating input names with all names in the standard definition of bisimulation in л-calculus. However, it does not automatically lead to an efficient algorithm,because symbolic bisimulation is indexed by conditions on names,and directly manipulating such conditions can be computationally costly. In this paper a new notionof bisimulation is introduced, in which the manipulation of maximally consistent conditions is replaced with a syst…

Ra, Rb transformations were successfully applied to establish invertibility theory for linear and quasi-linear finite automata over finite fields. In aprevious paper, the authors generalized R., Rb transformations to deal with nonlinear memory finite automata, and gave sufficient conditions for weak inverse andfor weakly invertible memory finite automata and inversion processes concerned;methods by transformation to generate a kind of nonlinear memory finite automatasatisfying one of these sufficient condit…

The current computer-aided technologies in design and product development, the evolution of CAD modeling, and a framework of multi-volume CADmodeling system for heterogeneous object design and fabrication are presented inthis paper. The multi-volume CAD modeling system is presented based on nonmanifold topological elements. Material identifications are defined as design attributes introduced along with geometric and topological information at the designstage. Extended Euler operation and reasoning Boolean o…

Driven by fast development of both virtual reality and volume visualization, we discuss some critical techniques towards building a volumetric VRsystem, specifically the modeling, rendering, and manipulations of a volumetric scene.Techniques such as voxel-based object simplification, accelerated volume rendering,fast stereo volume rendering, and volumetric "collision detection" are introduced andimproved, with the idea of demonstrating the possibilities and potential benefits ofincorporating volumetric mode…

The incremental radiosity method has been shown to be an efficienttechnique for providing global illumination in dynamic environments as it exploitstemporal coherence in object space. This paper presents an accelerated incremental radiosity algorithm, which is based on a dynamically followed partial matrix.This not only reduces the computation cost in determining incremental form-factorswhen the geometrical relationships between objects are constantly changing, but alsosimplifies the management of user inte…

Constraint-based solid modeling is the kernel part of current CADsystems. It has been widely used in supporting detailed design and variational design. However, it cannot support early stage design and is not easy-to--use becauseit demands fully detailed input description of a design. To solve these problems,researchers attempt to incorporate virtual reality techniques into geometric modeling systems. This paper presents a novel approach for interactive constraint-basedsolid modeling in a virtual reality en…

One of the key problems in a vision-based gesture recognition system is the extraction of spatial-temporal features of gesturing. In this paper anapproach of motion-based segmentation is proposed to realize this task. The directmethod cooperated with the robust M-estimator to estimate the affine parametersof gesturing motion is used, and based on the dominant motion model the gesturingregion is extracted, i.e., the dominant object. So the spatial-temporal features ofgestures can be extracted. Finally, the d…

Distributed Shared Memory (DSM) systems have gained popularacceptance by combining the scalability and low cost of distributed system with theease of use of single address space. Many new hardware DSM and software DSMsystems have been proposed in recent years. In general, benchmarking is widely usedto demonstrate the performance advantages of new systems. However, the commonmethod used to summarize the measured results is the arithmetic mean of ratios,which is incorrect in some cases. Furthermore, many publ…

Testing of parallel programs involves two parts-testing of controlflow within the processes and testing of timing-sequence. This paper focuses on thelatter, particularly on the timing-sequence of message-passing paradigms. Firstlythe coarse-grained SYN-sequence model is built up to describe the execution of distributed programs. All of the topics discussed in this paper are based on it. Themost direct way to test a program is to run it. A fault-free parallel program shouldbe of both correct computing result…

An O(n2) time approximation algorithm for the minimum rectilinear Steiner tree is proposed. The approximation ratio of the algorithm is strictlyless than 1.5. The computing performances show the costs of the spanning treesproduced by the algorithm are only 0.8% away from the optimal ones.

This paper presents a direct 3D painting algorithm for polygonalmodels in 3D object-space with a metaball-based paintbrush in virtual environment.The user is allowed to directly manipulate the parameters used to shade the surfaceof the 3D shape by applying the pigment to its surface with direct 3D manipulationthrough a 3D flying mouse.