Abstract:Many new distributed multimedia applications involve dynamic multiple participan ts, have stringent end-to-end delay requirement and consume large amount of ne twork resources. In this paper, a new DDDCLCMR (distributed dynamic delay-const rained least-cost multicast routing algorithm) is proposed to support these app lications. DDDCLCMR scales well because the source of the multicast tree needs o nly limited computation or may even not be involved in the route computation. Wh en group membership changes, the existing multicast tree is perturbed as little as possible. Simulation results show that DDDCLCMR performs very well in terms o f delay and cost for both static and dynamic multicast groups, compared with the best multicast algorithms known.

Abstract:The multiple hoist schedule problem is a critical issue in the design and contro l of many manufacturing processes. When the hoist number and station number are very large, finding optimal schedule is very hard. In this paper, the mathematic al model of multiple hoist schedule problem is discussed and a heuristic method about it is proposed by use of simulated annealing. A large number of examples o f random case indicate that this heuristic method is very useful, and satisfacto ry solution can be obtained with small amount of computation.

Abstract:The need to monitor the health of the global Internet has now become crucial. In this paper, an object-oriented model for network performance monitoring is dis cussed, which is adopted in the management of China Education & Research Network , a national information network of China. The current state of the network perf ormance management model is discussed first, which is helpful in formulating the setting of goals and requirements which a large-scale performance monitoring m odel must meet. Then an architecture solution to systematize the implementation of Internet monitoring and how it attempts to address these goals and requiremen ts are presented. Finally some examples about how to use this architecture model in real-life network monitoring are given.

Abstract:PVM (Parallel Virtual Machine) software is one of the most popular software envi ronments used on parallel workstation cluster system. However, with the rapid in crease in the speed of local area networks as well as in the performance of work station, PVM, which is based on the low-efficiency internal and the low-effici ency communication protocol, has become the bottleneck of the cluster systems. I n this paper, it is explained how PVM restrains the performance of clusters, by pointing out and analyzing the limitation of PVM's mechanism. Then the details o f the design and implementation of HPVM (High-performance PVM) are given, which is based on a high-speed reduced communication layer named FMP (Fast Message P assing).

Abstract:With the information available through World-Wide-Web becoming overwhelming, e fficient information gathering (IG) tools are necessary. Since the network resou rces are expensive, so IG is a resource-bounded task. The main purpose of this paper is to find an efficient gathering method for specific topic. This paper pr esents methods for predicting page's content without downloading it, designs dif ferent controlling strategies, and defines several kinds of page downloading pri ority measures. An IG system, TH-Gatherer, was built to test the methods, and d ifferent experiments were carried out. Through experiments, it was found that th e content of candidate pages can be predicted approximately without downloading. When the priority based gathering strategy and hybrid measure are used, the gat hering efficiency is four times of that of BFS strategy which is used by many cu rrent IG tools (including crawlers and off-line browsing tools). The method pre sented in this paper is suitable for resource-bounded, specific topic informati on gathering.

Abstract:In this paper, a kind of traffic prediction a nd congestion control policy based on FNN (fuzzy neural network) is proposed for ATM (asynchronous transfer mode). Congestion control is one of the key problems in high-speed networks, such as ATM. Conventional traffic prediction method fo r congestion control using BPN (back propagation neural network) has suffered fr om long convergence time and dissatisfying precision, and it is not effective. T he fuzzy neural network scheme presented in this paper can solve these limitatio ns satisfactorily for its good capability of processing inaccurate information a nd learning. Finally, the performance of the scheme based on BPN is compared wit h the scheme based on FNN using simulations. The results show that the FNN schem e is effective.

Abstract:In this paper, the basic design ideas, recent analysis results and validity of the 17 NESSIE (new european schemes for signat ures, integrity, and encryption) candidate algorithms are introduced.

Abstract:Mobile computing is a new computing paradigm. A main feature of this paradigm is dynamically changing the binding between com putational components and computational locations, which brings new requirements to the design of distributed systems. In this paper, an abstract model for mobi le component systems is proposed. Not only Location, Component, Mobility and Res ource Access as the basic elements of mobile systems are identified in the abstr act model, but modeling mobile systems by basic elements, relationships among el ements and relationship changes is also characterized. Based on set theory and o perational reduction rules, these elements, relationships and mobility mechanism s are specified in a formal manner. The analysis and formal specifications can b e applied to the design basis of mobile systems and their specification languages.

Abstract:Generation of photo-realistic images of virtual nature scenes is a challenging topic in computer graphics. As a very important part of natural scenery, realist ic rendering of trees has attracted much attention. Trees have various types wit h different shapes and due to their complex structures, realistic modelings, ren dering and storage of trees are always a tedious task. To tackle the problem, di fferent rendering strategies ae employed according to different types of trees a nd different scenes. For broadleaf, the z-buffer shadow generation method is us ed based on primary functions of OpenGL, for conifer, a ray tracing algorithm in cluding texel-rendering technique is used, and for trees in the far distance, v olumetric texture mapping is employed in terms of ray tracing and volume renderi ng technique. The images produced show that the feasibility and validity of the proposed rendering techniques.

Abstract:Level of Detail (LoD) is a key technique for real-time rendering. A new real-t ime rendering algorithm incorporating view-independent algorithms and view-dep endent algorithms is presented in this paper. Firstly, a polygonal mesh model is symplified view-independently according to the different requirements of appli cations or the user-specified error. Then the simplified model is used in a vie w-dependent real-time rendering algorithm. Examples illustrate that the propos ed mesh simplification algorithm and rendering algorithm can accelerate the rend ering speed greatly, while the rendering error (evaluated by pixel) is very small

Abstract:In Chinese-English machine translation, the treatment of a complex sentence mus t not only depend on the individual clauses, but also review deeply the internal relation among the clauses in the complex sentence. In Chinese, there are lots of descriptive sentences with non-coordinating relation without certain languag e marks. To distinguish the internal relation among them and get the right Engli sh output from Chinese-English Machine Translation System, the integrated rules to distinguishing them are presented, and the method of judging dynamically the main clauses is put forward to solve the problem of localization of some rules. Finally the rules are verified in virtue of the experimental system.

Abstract:In this paper, a face detection algorithm based on the matching of multiple rela ted templates is presented. The templates are a series of related types: eyes-i n-whole and face itself, which are produced by affine transforms varying in str etch and pose from an average frontal face. The eyes-in-whole templates are us ed as the first search step for face candidates and then the face templates are matched. Finally some heuristic rules are used to verify face detection results. Experimental results obtained from images containing frontal and in-plane rota ted faces demonstrate the feasibility of this approach.

Abstract:In this paper, the boundary conformability of 3D constrained Delaunay triangulat ion is analyzed. Based on the theory of Delaunay triangulation, the feasibility of 3D constrained Delaunay triangulation is discussed emphatically. The algorith m of 3D constrained Delaunay triangulation of finite domain is designed. Applica tions in oil and geological exploration and mechanical part design are illustrat ed. The algorithm plays an important role in the computation and analysis of com plicated objects.

Abstract:Implicit trimmed surfaces are rarely studied since they have no parametric domai n. A method which is related to modeling and rendering of implicit trimmed surfa ces is presented in this paper. First the projection plane is transformed into xy-plane in which the regular grids are partitioned and trimmed areas are d efined by a parametric/implicit curve, then the grids left after trimming are pr ojected onto the implicit surfaces so as to realize polygonization of the implic it trimmed surfaces.

Abstract:Computer aided design applications and scientific visualization often need user -steered interactive display of very complex environments. Instead of rendering original complex models directly, multiple levels of detail (LoD) models are wi dely applied to graphics system at run time to achieve a great speedup. In this paper, a new BSP tree framework is presented that can incorporate dynamic LoD mo dels. This framework is designed for a multi-resolution model editing system. The tree construction algorithm and traversal routine for the multi-resolution BSP tree are discussed in detail.

Abstract:Traditional researches on the similitude between entities are excessively simpli fied and lack of intent. In this paper, firstly a detailed analysis on the analo gical relationship between entities is made, which concerns about not only the c ommon attributes, but also the redundant and conflicting attributes of analogica l entities, and it is explained from the point of view of extensive pertinence. Secondly different extensive similitudes are defined based on different decision -making principles, which coincide with different demands in decision-making c ircumstance. Finally a set of generalized logical operator combination rules in analogical reasoning is proposed, therefore this proposal remedies the limitatio n of invariable operation rule in conventional analogical reasoning.

Abstract:In this paper, a new fractal image coding algorithm is presented to process imag e coding by difference and approximation with various grey levels because the co ding time of classical fractal image coding algorithm is very long. In addition, some researches with respect to its feasibility in compression theory are also discussed and the theoretical foundation of the new algorithm is given. Based on the idea, a new concrete algorithm for realizing fractal image coding is design ed in the paper. The experimental results show that the new algorithm can improv e compression ratio and reconstruct high quality images while computational time of image coding is reduced greatly.

Abstract:The problem of knot-removal for B-spline curves is investigated in this paper. The sufficient and necessary condition for removing knots of B-spline curves e xactly is simplified. Based on the constrained optimization method, a new algori thm of knot-removal is derived by perturbing the control points of B-spline cu rves. This method can also be used to fair B-spline curves.

Abstract:In this paper, the basic principles of orthogonal experimental design method and genetic algorithm are discussed briefly, and the relation between them is analy zed in detail. The paper indicates that orthogonal experimental design method is a special case of genetic algorithm, i.e. a genetic algorithm with a fixed init ial population, an oriented mutation operator and one evolution epoch. It is sho wn that the orthogonal experimental design method can overcome minimum deception problems existing in genetic algorithm.

Abstract:The development background, the design and the implement technology of a databas e security application server are presented in this paper, which can realize imp ortant security characteristics of B kind of TCSEC (trusted computer system eval uation criteria) and TDI (trusted database interpretation). It is an economical, practical and effectual method.