Loading...
ISSN 1000-1239 CN 11-1777/TP

Table of Content

15 May 2005, Volume 42 Issue 5
Paper
A Review of Web Intelligence Research
Wang Bennian, Gao Yang, Chen Shifu, and Xie Junyuan
2005, 42(5):  721-727. 
Asbtract ( 436 )   HTML ( 1)   PDF (339KB) ( 606 )  
Related Articles | Metrics
Web intelligence is a new research direction for researchers, which is an integr ation of artificial intelligence and information technology on the new platform of the Web and Internet, an enhancement or an extension of them. Many fruits hav e been obtained in recent years, and many problems remain unsolved. The notion a nd research contents as well as the functions and technologic framework of Web i ntelligence are firstly discussed. Then some recent research developments that a re related to the key aspects of Web intelligence, including semantic Web and on tology, Web agent, and Web mining, are deeply surveyed, and at the same time som e further research stresses and trends are presented. Finally, the concept of wi sdom Web that is viewed as the goal and challenge of Web intelligence is discuss ed.
Survey on Gait Control Strategies for Biped Robot
Hu Lingyun and Sun Zengqi
2005, 42(5):  728-733. 
Asbtract ( 557 )   HTML ( 0)   PDF (258KB) ( 2262 )  
Related Articles | Metrics
As humanoid robots shift from research lab to human living environment, biped robots play a more important role in recent research. Peoples are attracted by bip ed robots for the difficulties in gait control since their dynamic equations are high-order highly-coupled and nonlinear. This paper presented the basic concept s in biped gait and major research methods in the filed of biped gait optimizati on and control. Characters of three major models including inverted pendulum, pa ssive gait model and mass-spring model are thoroughly discussed. Advantages and disadvantages of all these three models are exhibited by comparison. Followed wi th it, the two kinds of usually used constraints, stability criterion and energy constraint are introduced with abundant examples. For stability criterion, zero moment point (ZMP) criterion as the most useful constraints in biped gait gener ation research is emphasized. Finally three intelligent control methods (neuron network, fuzzy logic and genetic algorithm) with their combination methods (fuzz y neuron network, genetic neuron network and so on) were introduced at the end o f this paper.
Searching for Agent Coalition for Single Task Using Improved Ant Colony Algorithm
Xia Na, Jiang Jianguo, Wei Xing, and Zhang Ling
2005, 42(5):  734-739. 
Asbtract ( 267 )   HTML ( 0)   PDF (313KB) ( 362 )  
Related Articles | Metrics
Coalition is an important cooperative method in multi-agent system. It is a comp licated combinatorial optimization problem to search for the optimal, task-orien ted agent coalition. An ant colony algorithm is adopted to solve the problem. Du ring the process of solution, ants incline to select those agents who cooperate well before to form coalitions, which realizes the acquaintance mechanism perfec tly. A novel “second pheromone” is proposed to improve the ACA so as not to ge t in the premature convergence easily. The results of contrastive experiments sh ow that this algorithm is superior to other related methods both on the quality of solution and on the convergence rate.
An Immune Genetic Algorithm Based on Vaccine Autonomous Obtaining and Updating
Han Xuedong, Hong Bingrong, and Meng Wei
2005, 42(5):  740-745. 
Asbtract ( 424 )   HTML ( 0)   PDF (353KB) ( 478 )  
Related Articles | Metrics
Slow convergence to the global optimum has been one of the main problems in genetic algorithm. In order to increase the speed of convergence, an immune genetic algorithm based on vaccine autonomous obtaining and updating (IGAVAOU) is propos ed. Excellent individuals are selected from each generation population and vacci ne is obtained from these excellent individuals. Then individuals in succeeding population are vaccinated in stochastic way. Vaccination is a kind of operation by which allele in vaccine replace allele on individual corresponding locus. Vac cination can not only make excellent schemata proliferate, but also repair the s chemata destroyed by crossover and mutation operations. Population and vaccine r epertory influence each other and co-evolve so that they accelerate convergence to the global optimum. IGAVAOU's computation efficiency is analyzed based on the schemata theorem. IGAVAOU is verified by several typical functions. The results show the feasibility and validity of the algorithm.
Dynamic Enforcement of the Strict Integrity Policy in Biba's Model
Zhang Xiangfeng and Sun Yufang
2005, 42(5):  746-754. 
Asbtract ( 527 )   HTML ( 0)   PDF (517KB) ( 455 )  
Related Articles | Metrics
While the strict integrity policy (SIP) of Biba's model can be used to maintain integrity of data in computer systems, the integrity labels of both subjects and objects in a system are always kept static in SIP, which might lead to denial to some non-malicious access requirements and hence decreases the compatibility o f applications. Dynamic enforcement of this policy (DESIP) is presented, which c an increase compatibility of software while keeping system integrity as strictly as SIP can. The implementation of DESIP is also given based on RFSOS, a Linux-b ased operating system, which shows that the impact of the enforcement of DESIP o n system efficiency is less than 1%.
Constraint-Based Normalization Algorithms for XML Documents
Zhang Zhongping, Wang Chao, and Zhu Yangyong
2005, 42(5):  755-764. 
Asbtract ( 415 )   HTML ( 0)   PDF (644KB) ( 461 )  
Related Articles | Metrics
XML schema design is part and parcel of databases design. Based on the basic con cepts of XML documents, some related definitions are given. They are definitions of partial functional dependency, transitive functional dependency for XML docu ments, normal form for XML documents named from the first normal form to the thi rd normal form for XML documents, and lossless decomposition for DTDs. Normaliza tion rules for XML schema and two normalization algorithms of lossless decomposi tion are provided. Validity, terminability, and time complexity of these will al gorithms are proved. The efficiency of query and storage for XML documents norma lized is enhanced. These will establish theoretic foundation for preserving func tional dependency for XML documents, multi-valued dependency for XML documents, and further normalization research of XML schema design.
Associated Navigation on the Web According to Users' Activities
Yang Jie and Wu Guoqing
2005, 42(5):  765-770. 
Asbtract ( 342 )   HTML ( 0)   PDF (348KB) ( 342 )  
Related Articles | Metrics
With the growth of the Internet, World Wide Web increasingly helps people to make good use of rich information from local or remote site. The amount of Web page s is so enormous that users are destined to drown in the huge data of the Web wi thout any navigation. To provide a new navigation approach, a modified Markov ch ain model is introduced, which utilizes all group members' traces in the Web to recommend some potential useful Web sites and navigates people when they browse Web pages, while users' activities react to the model. Before that, an algorithm based on a semi-formal description of process is necessarily given for collecti ng desired data to gain top grade results. The method is also illustrated by ana lyzing the proxy server's access log in the prototype system.
Incremental Maintenance of Continuous Query Evaluator over XML Data Stream
Gao Jun, Yang Dongqing, Wang Tengjiao, and Tang Shiwei
2005, 42(5):  771-776. 
Asbtract ( 295 )   HTML ( 0)   PDF (353KB) ( 353 )  
Related Articles | Metrics
In the research of massive continuous XPaths evaluation over XML data stream, little has been done on the maintenance of the evaluator when the query set evolves. Due to the massiveness of the XPath set, it takes a high cost to reconstruct the evaluator each time. A new method is proposed to handle this problem. Based on the new transition-rules-counting automata, this method implements the increa se and removal of XPath query dynamically and incrementally, and therefore, avoi ds the high cost of reconstruction. In addition, XML structural constraints DTD can be exploited to improve the efficiency of the incremental maintenance and re duce the possible redundant space cost incurred in the incremental maintenance. The experiments show that the method proposed can efficiently maintain the evalu ator of the continuous query over XML data stream at a low cost of extra space r esource.
An Algorithm and Its Updating Algorithm Based on Frequent Pattern Tree for Mining Constrained Maximum Frequent Itemsets
Song Yuqing, Zhu Yuquan, Sun Zhihui, and Yang Hebiao
2005, 42(5):  777-783. 
Asbtract ( 350 )   HTML ( 0)   PDF (372KB) ( 578 )  
Related Articles | Metrics
The problem of discovering association rules has received considerable research attention and several fast algorithms for mining association rules have been developed. In practice, users are often interested in a subset of association rules . For example, they may only want rules that contain some specific items. Applyi ng such constraints as a pre-processing stepor integrating them into the mining algorithm can dramatically reduce the execution time. The problem of integrating constraints, that are Boolean expressions over the presence or absence of items , into the maximum frequent itemsets discovery algorithm is considered. An integ rated algorithm and its updating algorithm for mining maximum frequent itemsets with item constraints are presented and their tradeoff is discussed. which is ba sed on a novel frequent pattern tree (FP-tree) structure that is an extended pre fix-tree structure for storing compressed and crucial information about frequent patterns.
k-LDCHD—A Local Density Based k-Neighborhood Clustering Algorithm for High Dime nsional Space
Ni Weiwei, Sun Zhihui, and Lu Jieping
2005, 42(5):  784-791. 
Asbtract ( 405 )   HTML ( 0)   PDF (466KB) ( 647 )  
Related Articles | Metrics
Clustering is an important research in data mining. Clustering in high dimension al space is especially difficult for the spatial distribution of the data, too m uch noise data points, and the phenomenon that the distance between the distance s to the nearest and farthest neighbors of a data point goes to zero. By analyzi ng limitations of the existing algorithms, definitions such as k-neighborhood se t and k-radius are introduced. A local density based k-neighborhood clustering a lgorithm k-PCLDHD is proposed to solve this problem. To improve the algorithm's efficiency, the optimized algorithm k-LDCHD is proposed. The definition of refer ence distance is applied to make a pretreatment to the data set, thus avoiding q uite a lot of scans to the data set after using double reference points, and the effectiveness is improved greatly. The theoretical analysis and experimental re sults indicate that the algorithm can solve the problem of clustering in high di mensional space. It's effective and efficient.
Functional Dependencies and Inference Rules for XML
Lü Teng, and Yan Ping
2005, 42(5):  792-796. 
Asbtract ( 586 )   HTML ( 0)   PDF (305KB) ( 468 )  
Related Articles | Metrics
Functional dependency is an important semantic representation both in relational databases and XML documents. Analyzed in this paper are the differences of func tional dependencies when they are applied in XML documents and relational databa ses. A concept of functional dependency for XML based on DTD path expressions is proposed. The advantage of this definition is that it can represent the functio nal dependencies not only between the values of attributes and elements, but als o between the nodes of elements. And finally, a group of complete inference rule s about XML functional dependency is given, which is significant to the implicat ion problem of XML functional dependency.
A Grid & P2P Trust Model Based on Recommendation Evidence Reasoning
Zhu Junmao, Yang Shoubao, Fan Jianping, and Chen Mingyu
2005, 42(5):  797-803. 
Asbtract ( 391 )   HTML ( 0)   PDF (412KB) ( 463 )  
Related Articles | Metrics
Under mixed computing environment of grid and P2P(Grid & P2P), grid nodes provide the service with QoS guarantee. However, sharing computing resources of P2P no des is the user's volunteer action without QoS guarantee. The user is not respon sible for his actions. Therefore it's difficult to establish the trust relations hip among users with traditional trust mechanism. Referring to social people tru st relationship models, a grid & P2P trust model based on recommendation evidenc e reasoning is designed to solve the problem by building a recommendation mechan ism in Grid & P2P and integrating the recommendation evidence with the D-S theor y. Theoretical analysis and simulations prove that the model can tackle the trus t problem under Grid & P2P in a simple and efficient way.
A Domain of Interest Based Novel Search Scheme in P2P Networks
Yang Jian, Lü Zhihui, Zhong Yiping, and Zhang Shiyong
2005, 42(5):  804-809. 
Asbtract ( 386 )   HTML ( 0)   PDF (309KB) ( 463 )  
Related Articles | Metrics
A novel search scheme is proposed to address the efficiency and scalability issu es in unstructured peer-to-peer networks. Unlike the notorious search scheme of flooding in unstructured peer-to-peer networks, the proposed scheme is based on the domain of interest that is formed by nodes sharing the same interest. Search request is propagated within the domain of interest, and the efficiency of sear ch process is very high after nodes in the same domain of interest get familiar with one another. In the proposed scheme, attributes of document are described b y metadata using RDF statements to support flexible queries; nodes having the sa me metadata belong to the same domain of interest. With the facility of metadata selection window and metadata replication, performance of the proposed search s cheme is further improved. Simulation results prove the effectiveness and efficiency of the proposed scheme.
An Efficient Queuing and Switching Scheme for Multicast in High-Speed Routers
Song Meina, Song Junde, and Zhan Xiaosu
2005, 42(5):  810-817. 
Asbtract ( 405 )   HTML ( 0)   PDF (478KB) ( 426 )  
Related Articles | Metrics
Many emerging Internet applications are multicast traffic. The queuing and switc hing scheme for multicast in high-speed routers is one of the key elements to en able the multicast traffic traverse the complex network environments. Ideally in order to guarantee the fairness between the unicast and multicast traffic we sh ould not differentiate them deliberately when queuing and scheduling. Since the increase of multicast traffic will exhaust the resource, the service for unicast traffic will be influenced. When the two types of traffic coexist, how to provi de the fairness between them from the point of queuing view desiderates to be re solved. Based on the shared memory switching architecture, an efficient queuing scheme for multicast packet switching routers is proposed. And the corresponding buffer management and scheduling algorithm according to multicast ratio and fan out are also presented based on the proposed queuing scheme. On three phases, wh ich are the input buffer, the shared memory and the buffer of egress NP, the ban dwidth and buffer allocation for multicast packets is decided according to the m ulticast traffic ratio and the mean fanout. Performance evaluation of the propos ed system shows that better average delay and loss performance can be achieved i n comparison with the ESLIP system under heavy offered load, which is applied fo r high-end routers of Cisco.
A δ-Degree-Based Clustering Algorithm in MANET
Zhao Chunxiao, and Wang Guangxing
2005, 42(5):  818-822. 
Asbtract ( 332 )   HTML ( 0)   PDF (293KB) ( 370 )  
Related Articles | Metrics
Describing briefly the characteristics of mobile ad hoc networks and analyzing the disjoint, overlapping and hybrid clustering, the related works are compared. Because HD clustering considered only node degree as clustering standard and thi s has caused frequently cluster head change, a reconfiguration of the system is often unavoidable. To keep the topology stable, a new definition of δ-degree is given in view of the highly dynamic topology and absence of any fixed infrastru cture in MANET. According to δ-degree definition, δ-degree sequence stabilize relatively fairly and steady cluster structure is produced. Analyzing the link r elationship between two adjacent nodes, an ad hoc network model is set up. A hyb rid clustering algorithm(δ-DHCA) is therefore proposed on the basis of δ-degre e. The hybrid clustering can be reduced to find a maximum independent set (MIS) problem, but this is a well-known NP-hard problem and the proposed scheme is an approximate algorithm based on polynomial time. The correctness of the algorithm is proved. Analytical and simulation results show that δ-DHCA outperforms LCC and HD clustering algorithms.
IP Multicast in DiffServ Network: Problems and Solutions
Gao Qian and Luo Junzhou
2005, 42(5):  823-829. 
Asbtract ( 264 )   HTML ( 0)   PDF (311KB) ( 423 )  
Related Articles | Metrics
In the next generation Internet,there will be more and more applications that re quire both quality of service guarantees and multicast transmission. From the st andpoint of performance and implementation,users and network service providers c an both benefit from the integration of DiffServ and multicasting, as DiffServ i s a scalable solution for supporting QoS in the Internet while multicasting prov ides a method for conservation of network bandwidth. However,the integration of DiffServ and multicast becomes difficult due to the fundamental differences betw een them. Problems existing in DiffServ multicast provision and several solution s proposed in recent years are detailed and discussed,classified and compared. P ossible future directions in this research area are pointed out.
A MA Model with Application Components Being Dynamically Scalable
Yang Juan, Qiu Yuhui, Li Jianguo, and Zheng Qiang
2005, 42(5):  830-834. 
Asbtract ( 381 )   HTML ( 0)   PDF (329KB) ( 373 )  
Related Articles | Metrics
How to reduce the system's communication cost is a hard problem because of its s trong reliability on the differences incurring by the variant kinds of mobile ag ents in their execution environments most of which are influenced by synthetical reasons. Making the application components movable inter-system platforms can p artly resolve this problem. A new MA system model is given, which divides movabl e components from fixed components to reduce the communication cost. Resource al locating strategy applied on it is an expanding version of the Avrampopoulos alg orithm by adding the parameter to improve its robustness. Experimental results p roved its usability and effectiveness.
PIWA-LOC—A Parallel Resampling Algorithm for Large Images on Cluster Systems
Jiang Yanhuang, Yang Xuejun, and Yi Huizhan
2005, 42(5):  835-843. 
Asbtract ( 331 )   HTML ( 0)   PDF (567KB) ( 295 )  
Related Articles | Metrics
Image resampling is a computation-intensive task and can be found in many applic ations. To achieve better performance and generalization, a distributed parallel geometric correction algorithm is improved and a parallel resampling algorithm called PIWA-LOC is presented under cluster systems. In PIWA-LOC, the input image is partitioned evenly. Each computing node calculates the corresponding area in the output space for the local input subimage, and performs resampling for the output pixels in this area. A data structure is put forward to save irregular-sh aped output subimages, and a piece-wise linear approximation method is explored to get the area of the output subimages, which achieves good generalization for the algorithm. Experimental results show that the algorithm is suitable for many complex geometric transformations, and achieves good parallel performance for l arge image resampling tasks, especially under a cluster system with high network bandwidth.
Combined Multiple Classifiers Based on a Stacking Algorithm and Their Application to Chinese Text Chunking
Li Heng, Zhu Jingbo, and Yao Tianshun
2005, 42(5):  844-848. 
Asbtract ( 676 )   HTML ( 0)   PDF (304KB) ( 520 )  
Related Articles | Metrics
Comparing with the combined multiple classifiers based on a voting algorithm, a two-layer classifier-combination experimental framework is presented for Chinese text chunking, in which four diverse classifiers (transformation-based learning , sparse network of winnow, support vector machine, and memory based learning) a re combined with a stacking algorithm. The relevant information is incorporated into the two-layer framework as input feature vectors to construct more complete contextual models. The chunking experiments are carried out on the HIT Chinese Treebank Corpus. Experimental results show that it is an effective approach, whi ch can achieve an F score of 93.64.
A BinaryEncoding Differential Evolution Algorithm for Agent Coalition
Wu Zhifeng, Huang Houkuan, and Zhao Xiang
2005, 42(5):  848-852. 
Asbtract ( 319 )   HTML ( 0)   PDF (519KB) ( 350 )  
Related Articles | Metrics
In multi agent systems, it can improve agent’s abilities of problem solving to form coalition. So, coalition is an important cooperative method in multiagent systems. But the number of the possible coalitions is exponential since each agent can form coalition with others. Essentially, forming agent coalition is a combinatorial optimization problem. As a modern optimization method, differential evolution (DE) introduced by Storn and Price in 1997 is one of the most successful evolutionary algorithms which are adopted to solve this problem. The original differential evolution which is based on the individual differential reconstruction idea is designed for the global continuous optimization problem. In order to solve the combinatorial optimization problem by DE, in this paper, a novel binaryencoding differential evolution (BDE) algorithm is presented and applied to find out agent coalition fast and efficiently. By using a Sigmoid function, the new algorithm constrains the result of mutation operator in {0,1}, so as to adopt the combinatorial optimization problem. Some simulations which include 30 agents have been achieved for the novel binaryencoding differential evolution, genetic algorithm (GA) and ant colony algorithm (ACA). The experimental results show that the new algorithm is feasible and efficient. It is superior to other related methods such as GA and ACA both on the quality of solution and on the convergence rate.
A BinaryEncoding Differential Evolution Algorithm for Agent Coalition
Wu Zhifeng, Huang Houkuan, and Zhao Xiang
2005, 42(5):  848-852. 
Asbtract ( 232 )   HTML ( 0)   PDF (519KB) ( 361 )  
Related Articles | Metrics
In multi agent systems, it can improve agent’s abilities of problem solving to form coalition. So, coalition is an important cooperative method in multiagent systems. But the number of the possible coalitions is exponential since each agent can form coalition with others. Essentially, forming agent coalition is a combinatorial optimization problem. As a modern optimization method, differential evolution (DE) introduced by Storn and Price in 1997 is one of the most successful evolutionary algorithms which are adopted to solve this problem. The original differential evolution which is based on the individual differential reconstruction idea is designed for the global continuous optimization problem. In order to solve the combinatorial optimization problem by DE, in this paper, a novel binaryencoding differential evolution (BDE) algorithm is presented and applied to find out agent coalition fast and efficiently. By using a Sigmoid function, the new algorithm constrains the result of mutation operator in {0,1}, so as to adopt the combinatorial optimization problem. Some simulations which include 30 agents have been achieved for the novel binaryencoding differential evolution, genetic algorithm (GA) and ant colony algorithm (ACA). The experimental results show that the new algorithm is feasible and efficient. It is superior to other related methods such as GA and ACA both on the quality of solution and on the convergence rate.
A Time Performance Evaluation Method for Workflow Based on Extended Timed Petri Net
Jiang Hao and Dong Yisheng
2005, 42(5):  849-855. 
Asbtract ( 337 )   HTML ( 0)   PDF (401KB) ( 394 )  
Related Articles | Metrics
The performance evaluation is an important aspect in analysis and evaluation of workflow models. In this paper, the general Petri net models for business proced ures are introduced first and then the extended time model of workflow nets is e stablished. On the basis of reachability graph, the concepts of simple routing g raph and transformable subnets are advanced. By using net transformation methods keeping response time and assigning probability, the extended timed workflow ne ts are simplified. The algorithm for searching transformable subnets and the met hod for calculating time performance of workflow models are provided.
Research on Collaborative Interaction Based on Gesture and Sketch in Conceptual Design
Ma Cuixia, Wang Hongan, Dai Guozhong, and Chen Youdi
2005, 42(5):  856-861. 
Asbtract ( 390 )   HTML ( 0)   PDF (315KB) ( 449 )  
Related Articles | Metrics
An interaction pattern based on gesture and sketch provides a natural and harmonious user interface for collaborative operation in conceptual design, which promotes the development and application of collaborative system. Based on the user- centered design, different conceptual design process is analyzed and the new col laborative design method based on gesture and sketch is given; a product informa tion carrier based on sketch is studied; Based on the gesture operation, the col laborative context-awareness and the description model are provided; the sketch interaction design for synchronous editing is analyzed and the bi-direct constra int solution is put forward. A convenient method of collaborative design is prov ided to develop design efficiency and improve human-computer interaction.
A Spoken Language Understanding Approach Based on TwoStage Classification
Wu Weilin, Lu Ruzhan, Duan Jianyong, Liu Hui, Gao Feng, and Chen Yuquan
2005, 42(5):  861-868. 
Asbtract ( 424 )   HTML ( 0)   PDF (895KB) ( 490 )  
Related Articles | Metrics
Spoken language understanding (SLU) is one of the key components in a spoken dialogue system. One challenge for SLU is robustness since the speech recognizer inevitably makes errors and spoken language is plagued with a large set of spontaneous speech phenomena. Another challenge is portability. Traditionally, the rulebased SLU approaches require linguistic experts to handcraft the domainspecific grammar for parsing, which is timeconsuming and laboursome. A new SLU approach based on twostage classification is proposed. Firstly, the topic classifier is used to identify the topic of an input utterance. Then, with the restriction of the recognized target topic, the semantic slot classifiers are trained to extract the corresponding slotvalue pairs. The advantage of the proposed approach is that it is mainly datadriven and requires only minimally annotated corpus for training whilst retaining the understanding robustness and deepness for spoken language. Experiments have been conducted in the Chinese public transportation information inquiry domain and the English DARPA Communicator domain. The good performance demonstrates the viability of the proposed approach.
Unsupervised Texture Segmentation Based on FCM
Jiang Xiaoyue, Zhao Rongchun, and Jiang Zetao,
2005, 42(5):  862-867. 
Asbtract ( 346 )   HTML ( 0)   PDF (375KB) ( 370 )  
Related Articles | Metrics
As the cluster number of texture in an image is always unknown, the unsupervised classification is more valuable than the supervised classification. Based on th e concept of a good cluster which should have the minimum intra-cluster distance and the maximum inter-clusters distance, the ratio of intra-cluster to inter-cl uster distance is applied as the validity function. However, the increase of ini tial cluster number will influence the sum of cluster diameters and the inter-cl uster separation distance. Therefore the maximum cluster diameter and minimum in ter-cluster separation distance are provided instead, which is influenced by the initial cluster number more slightly and shows the essential of the cluster str ucture. Due to the relationship of FCM convergent speed with the initial cluster number, the convergent speed is introduced as the penalization factor to the va lidity function and a new validity function nRII is proposed. Compared with othe r validity functions, the nRII validity function can effectively prevent the ove r-clustering problem and give out a more exact estimation of the cluster number.
Research and Implementation of an Extended Administrative Role-Based Access Control Model
Long Qin, Liu Peng, and Pan Aimin
2005, 42(5):  868-876. 
Asbtract ( 361 )   HTML ( 0)   PDF (460KB) ( 486 )  
Related Articles | Metrics
RBAC(role-based access control) is emphasized recently due to its simpleness, fl exibility, fine-grained control ability and strong usability, and has been prove n to be efficient to improve security administration with flexible authorization management. During the past decade, RBAC has been studied by many researchers a nd many extensions have been proposed to perfect it. Now, studies on the object part of RBAC model are relatively insufficient compared with those on the user-r ole part. A new administrative role-based access control model is proposed in th is paper, which extends the proposed NIST standard for RBAC effectively. The new model is more integrated and closer to most organizational structures by extend ing the abstracts about the objects and access type, and it can be administrated more conveniently combining with ARBAC 96 model. Based on this extended model, a secure network file system prototype is implemented.
Paper
An Efficient Secret Sharing Scheme Realizing Graph-Based Adversary Structures
Guo Yuanbo, Ma Jianfeng, Wang Yadi
2005, 42(5):  877-882. 
Asbtract ( 321 )   HTML ( 0)   PDF (327KB) ( 441 )  
Related Articles | Metrics
Most of the existing secret sharing schemes are constructed to realize general access structure, which is defined in term of authorized groups of participants, and is unable to be applied directly to the design of an intrusion tolerant syst em. Instead, the generalized adversary structure, which specifies the corruptibl e subsets of participants, can be determined directly by exploiting the system s etting and the attributes of all participants. An efficient secret sharing schem e realizing graph-based adversary structures is proposed. The scheme requires le ss computational costs and storage overhead than the existing ones. Furthermore, it is proved that the scheme satisfy both the required properties of the secret sharing scheme, i.e., the reconstruction property and the perfect property.
Research on Segmenting and Volume Rendering of Irregular Seismic Events
Ma Renan, Zhang Erhua, Yang Jinyu, and Zhao Chunxia
2005, 42(5):  883-887. 
Asbtract ( 303 )   HTML ( 0)   PDF (359KB) ( 423 )  
Related Articles | Metrics
A new local-information-based segmenting method (LI-RGA) of irregular seismic ev ents is given. This method solves the fussy decision of homogeneity criteria in minimum-variance-based region growing algorithm (R-RGA) and the very slow segmen ting in the assessment-function-based region growing algorithm (RM-RGA). The seg menting precision of LI-RGA is not so good as the RM-RGA, but the precision is e nough to interpret of irregular seismic events. According to the features of sei smic data, the traditional ray-casting algorithm is modified, and the displaying time is saved. By defining segmented regions as a mask, then combining them wit h the advanced ray casting algorithm to change the transfer function, the irreg ular seismic event can be rendered definitely. The test result proves that this method is more effective than the traditional ray-casting algorithm, and can con struct and display unidentifiable irregular seismic events of data set and other important seismic events.
A Survey of Virtual Human Skin Deformation
Li Yan, Wang Zhaoqi, and Mao Tianlu
2005, 42(5):  888-896. 
Asbtract ( 388 )   HTML ( 1)   PDF (495KB) ( 684 )  
Related Articles | Metrics
Skin deformation is an important problem in virtual human modeling, and two main goals are realistic and real-time deformation. First, the geometrical models of 3D human body and human skin are presented, and then a novel classification met hod is given. According to the method, the skin deformation is firstly classifie d into two classes named surface-model skin deformation and multi-layered-model skin deformation, and then the most popular surface-model skin deformation is di vided into four sub-classes, namely, rigid deformation, local deformation operat ors, SDD, and interpolation deformation. Each class is described in detail cover ing the merits and shortcomings. Finally, the problems of skin deformation and f uture directions are discussed.
Two Improvement Strategies for Particle Swarm Optimization
Dou Quansheng, Zhou Chunguang, and Ma Ming
2005, 42(5):  897-904. 
Asbtract ( 270 )   HTML ( 0)   PDF (466KB) ( 483 )  
Related Articles | Metrics
Particle swarm optimization (PSO) method was proposed by Kennedy and Eberhart in 1995, which can be used to solve a wide array of different optimization problem. The PSO idea is inspired by natural concepts such as fish schooling, bird floc king and human social relations. Some experimental results show that PSO has gre ater “global search” ability, but the “local search” ability around the opti mum is not very good. In order to enhance the “local search” ability of the traditional PSO, two improvement methods for the PSO, that is, PSO with simulated annealing (PSOwSA) and PSO with division of work (PSOwDOW), are introduced by analyzing deeply the traditional PSO. Experiments for several benchmark problems s how that PSOwSA and PSOwDOW can overcome the fault of traditional PSO and increa se the optimization power of the particle swarm.