New research is currently in prog ress to apply Virtual Environment to product assembly because Virtual Environment can prov ide a new type of user interface. This paper introduces the approaches in this domain. We describe the system st ructure, functionism, advantages and problems of Virtual Assembly Planning, w hich are key issues in Virtual Assembly . In the last part of this paper we present the architecture and representat ive features of a typical system, the Virtual Assembly Desig n Environment( VADE) .

Product development , which is subject to cost and time pressure, increasingly calls for intensive use of numerical methods , for example the finite element method( FEM) . The growing complexity of design tasks as well as the rapidly increasing scope of functions of commercial software often makes it too difficult for the product developer to apply these methods. Therefore, the know-how of experts in computational engineering is required. The following approaches can reduce the resulting gap between design and computation, thus enabling a successful robust and more time-effective product development process.

Cooperative pattern design is one of the typical applications of Computer Supported Cooperative Work(CSCW )，and the concurrent accesses and controls of cooperadve data are the central problem．In this paper，based on an Internei-based cooperative pattern design protocol system(CoDesign)developed by the authors，an idea of treating the data operations by the users as the operations of database transaction processing in the cooperative process，and formally research the transaction model of describing the operational behavior．This technology can solve the cooperative data procesing problem effectively．

In this paper, we will discuss the implementation of TCMMDB, which is a query platform of distributed multi-database. First we will introduce the architecture of TCMMDB. Then the key techniques that implement the system are discussed in detail. These techniques are optimization of distributed query, synchronization of distributed query and the exception handle of distributed query.

In order to develop performance-sensitive applications in heterogeneous environments real-time CORBA comes into the focus of research on distributed computing modes. ACE( Advanced Communicat ion Environment ) is a programming framework with concurrency core and distributed mode for TAO( The ACE ORB—an ORB end system) . In this paper, we analyze the module structure of ACE. Also we describe and enhanced communication environment EACE with ATM support based on ACE,which constructs the communication programming framework for QoS-support CORBA.

Some typical approaches of SPC in the multi-specification and small-batch production are analysed, and an applict ion model of SPC is proposed in this paper.

A new algorithm of minimum zone method for evaluating straightness error is put forward in this paper. It is the valid characteristic point method with the rapidly contracted constraint zone. Its mathematical model is established and its fundamental is illust rated in detail, also, its basic procedure is described. By applying the judging criteria of alternate and characteristic points to search the gradient of enveloping line, the new algorithm sets up automatically a constraint zone of the gradient of the enveloping line of the minimum zone and contracts it rapidly. It Searches out quickly the gradient of the enveloping line of the minimum zone and gets exactly the minimum value of the straightness error. A large number of examples show that the new algorithm has many advantages such as a high ratio of success in first searching, fast calculation speed and few iteration. The new algorithm can be popularized for evaluating other form error. It can also be applied to compute assistant measuring system on line.

In this paper ,the probability of mismatch is given on basis of the research situations of computer aided tolerancing (CAT) . The rest raint relations of size and geomet ric tolerance are studied that have affected on product behavior. The synthesis optimization modeling of size ,geomet ric tolerance is put forward.

The concept of elementarily funct ional surfaces and MGDE in TTRS theory is led into. The corresponding rules between functional surfaces and types of form tolerances & between the association of functional surfaces and types of position tolerances are studied. The scheme of computer-aided generation of geometric tolerance types is brought forth. An example is analyzed to show the scheme to be effective.

All cost s incurred in a produce life cycle consist of quality loss and manufacturing cost s. In this paper we present a new approach for robust tolerance design to make total cost minimum. The method adapt s Response Surface Methodology to carry through robust tolerance design.

A formulation for designing process tolerances to maximize the process capability index of each operation is int roduced. The multi2objective programming problem is changed into a single objective one and an example is employed to illust rate the applicability of this model.

The non2contact f reeform surface meaurement system the authors are developing is int roduced in this paper. The component s of it s software and hardware are analyzed. Under the two different circumstances of CAD model is known and unknown ,some critical problems are studied such as the measurement point s adaptive localization ,the measurement path ,layout and measurement data disposal etc.

High sound quality improves acceptance of technical products. To achieve high sound quality noise effect s must be analysed and related to their technical origins so const ruct ive modifications can be performed . In this paper dependence of sound emissions on common const ruct ive properties is described.

With the method of t ransforming the polar curve into(ρ, θ) descartes coordinate system, an efficient curve design method is presented here w hich may be useful for the product silhouet te curve design.As examples, some real silhouet te curve are constructed w ith this method.

This paper is to ex pat iate on the design of a balance steelyard system cont rolled by micro-computer. The system has passed prov incial ident if icat ion and applied some cement factories. Its performance is proved to be stability and credibility. The system helps to improve productivity and product quality remarkably.