Abstract:At present, the contradictory between the high speed process ability and the low speed I/O devices has become one of the main problems in multicomputers. So it is necessary to develop parallel file system of high performance. PFS is a parallel file system designed for a multicomputer, one of the 863-plans. Its goal is to decentralize the management of I/O devices into multiple process nodes so that files can be distributed into different physical devices controlled by different process nodes, and accessed as parallel as possible. This paper states the basic design, implementation methods and approximate performance analysis about PFS.

Abstract:With the developing of parallel processing technology, more and more highperformance parallel computer systems have been developed. The convenient and flexible parallel programming environment plays an important role in the spread of parallel computing. How to write efficient parallel codes and how to convert the existing sequential applications into parallel codes have become a very important issue in parallel processing.

Abstract:Granularity control is a main problem of parallel execution of logic programs.This paper first introduces the concepts of granularity and granularity value to numerically reflect the response time of executing a goal. Then it constructs a computation model to estimate the granularity value of each goal. The control strategy of granularity in the parallel model is also presented.

Abstract:In persistent environments (e. g., persistent OOPLs, OODBSs), twodifferent kind of physical storage- memory and disk are involved. An abstract storage level should be developed to hide physical details. The virtual object storage(VOS) proposed in this paper is such an abstract storage level on which persistent objects and transient objects can be manipulated uniformly. The author has developed the dual-copy model for the VOS implementation. And the benefits of the VOS approach for persistent OOPL design and implementation are illustrated by the experiences with XDPC+ +, a persistent OOPL based on C+ +.

Abstract:This paper studies the syntactic structure for adherence Adh (IM) of a language L. With the aid of the parser tree of L, the authors analyse some characteristics of words belonging to Adh (L), and prove iteration theorems for adherences of regular languages and context-free languages, thus solving the problem on syntactic structure for the adherence of corresponding languages. Moreover, they present the application of itera-tion theorems to prove some adherence of languages are not adherences of regular languages or context -free languages.

Abstract:Based on the classification of the venices of 8 subcubes and Half-spaces of CSG model, this paper presents a compound algorithm to convert the CSG model to Octree representation of 3D objects. The computation results on several objects show that the algorithm can meet the needs of automation of 3D-packing.

Abstract:In shape from shading, iterative algorithms are often used to compute the surface derivatives. These algoritghms are, however, very time-consuming when the iterations are performed on the original image. In this paper the authors propose a multiresolution method which makes use of the orthonormal wavelet transform to construct a multiresolution pyramid and let most iterations be performed on the low resolution images to give good predictions of the initial values of the surface derivatives of higher resolution images and thus save many computations. On the other hand, the nonlinearity of imaging makes the direct reduction of the image resolution not an optimal way of utilizing the multiresolution method. Instead, they construct the pyramid of the norm of the surface direction. They prove that this strategy gives out excellent results when the surface is smooth and the support length of the wavelet is small. Factors that may affect the selection of the wavelet in the multiresolution shape form shading are also studied. Experiments show the superiority of this strategy to other methods.

Abstract:Software of today becomes more and more large, and it provides more and more services. Usually, the“selection-execution”model is used to invoke available services of a software. Therefore, there may be many services in a software which have never been invoked by its users, or whose existence is unknown to its users. This paper introduces a notion called active services. An active service is a service which can invoke itself under some circumstances, although its users may not know its existence. It also presents three basic models of active services and demonstrates their applications in various software.

Abstract:Object-oriented software developing method comes into a fusion period and is becoming mature along with object-oriented implementation technology is developing rapidly. Based on Jade Bird engineering and current verious methods, the authors proposesed a object-oriented software developing method named OOSDM (object-oriented software developing method). This paper gives its objec model and system construction.