Computer Science

Key Technologies and Applications of Internet of Things

LIU Qiang,CUI Li,CHEN Hai-ming

Computer Science. 2010, 37 (6): 1-4.

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The Internet of things (IoT) has been paid more and more attention by the government, academe and industry all over the world. This paper introduced the concept of IoT, the basic characteristics and attributes. It also described the system structure, development phases and the future trend. The key technologies of Io T were discussed taking the wireless sensor network as an example. The application of IoT was illustrated by its typical use in environment monitoring.

Analyzing Relationship of News Video Stories : An Overview

WU Ling-da,WEN Jun,CHEN Dan-wen,YUAN Zhi-min

Computer Science. 2010, 37 (6): 5-10.

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Analyzing relationship of news video stories is a special clustering of stories based on news events. "Story" is the unit which contains full semantic information in hierarchy units. It is the best semantic unit for video analyzing,searching and organizing. This paper gave an overview of existing method and classified them into three categories;the approach based on text similarity, the approach based on multi-modal similarity and the approach based on keyframe visual duplicate. Their advantages and limitation were discussed and compared in detail. At last, this paper presented some trends in this field.

Overview of Data Management in Wireless Sensor Networks

ZHANG Shao-ping,WANG Ying-hua,LI Guo-hui

Computer Science. 2010, 37 (6): 11-16.

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Wireless sensor networks are data-centric networks in nature,they deal with continuous data streams collected by sensor nodes. Therefore, existing data management technologies view wireless sensor network as a distributed database system composed of continuous data streams which come from the physical world. Due to the limitations of Sensor nodes' computing power, storage capacity, communication capabilities and battery energy, combined with the characteristics of flash memory and data streams,these lead to some challenges that the traditional distributed database systems have not encountered for data managements.This paper introduced the database system architecture, data storage and index technologies, data models, and query processing and optimization technologies for wireless sensor networks.

Review and Prospect of Tree Modeling Techniques

ZHOU Jun,CHEN Lei-ting,LIU Qi-he,LI Yan-mei,RAO Yun-bo

Computer Science. 2010, 37 (6): 17-22.

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Tree modeling is an important issue that interests both computer graphics and computer vision communities.This paper surveyed the recent techniques for tree modeling from the point of view of graphics, which are based on rule-based modeling,sketch-based modeling and image-based modeling technictues,and tried to characterize these algorithms according to their base techniques, assumptions, limitations and range of utilization. Some typical methods were summarued and the state-of-the-art progress was presented. The fundamental principles behind each technictue were also analyzed and compared. Finally, some future research issues on tree modeling were highlighted.

Document Clustering Algorithm Based on Dynamic Interval Mapping

SUN Yong-lin,LIU Zhong

Computer Science. 2010, 37 (6): 23-27.

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Archival storage is becoming a research hotspot with information digitization accelerating,where space utihnation and scalability are very important Using content based chunking storage to achieve data deduplication is an effective way to improve storage space utilization, however, it is inefficiency to find shared chunks in all of the huge scale of archival data. We introduced the thought of dynamic interval mapping to information clustering, and presented the DC-DIM(Document Clustering algorithm based on Dynamic Interval Mapping).The algorithm uses chunking and feature extraction methods to generate the fcaturcset of document, and map it on interval links, then choose the document's storage container according to its feature-set's distribution on interval links.By this way, those documents with high similarity(shared a lot of contents) will be clustered, then, it will be very convenient to improve the space utilization and data management.

Topology Optimization Based on Small-world Model in Wireless Sensor Networks

JING Wei-peng,LIU Ya-qiu,YANU Xian-hui

Computer Science. 2010, 37 (6): 28-31.

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According to wireless sensor network nodes energy consumption, hardware failure and communication factors lead to link failure,an evolving network method based on complex network theory of small-world Kleinberg model was proposed,which uses long chains and short chains in partial view information to build inter-cluster topology in wireless sensor network. Theoretical analysis and simulations show that the network lifetime is longer 25% than DECDC in the WSN topology which uses this method when the node failure probability is 0. 2 and it has a good balance of energy consumption and lower cost. Thus the topology which uses the method to build has fault tolerant and good robustness.

NpuESB:An BPM Environment Based on Enterprise Service Bus

FU Ning,ZHOU Xing-she,XUE Wen,ZHANG Dong-yi

Computer Science. 2010, 37 (6): 32-35.

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The hierarchical architecture of an Enterprise Service Bus (ESB) based BPM environment,NpuESB,was proposed in this paper. NpuESB is a rapid BPM application development platform grounded on the infrastructure of JBI specification-compliant distributed ESB. By introducing ultra server and process management module, NpuESB enables centralized management of the ESB environment and BPM application workflows. Workflows in ESB environment can be modeled with the formal method based on Pi calculus proposed in this paper. Some important design and implementation considerations for the distributed ESB and management tools were also discussed. Application tests of the prototype system demonstrate NpuESB's effectiveness. Compared with traditional techniques and tools, NpuESB delivers better flexibility and scalability meanwhile stays compatible with legacy systems, thus reduces EAI application development and maintenance costs to a greater extent.

Study on the Effect of Quantization Factors on Transmission of Video Streams through IEEE Simulation of Image Quality Performance in 802. 11 b/e Wireless Local Area Networks

LIAO Yong,YANG Shi-zhong

Computer Science. 2010, 37 (6): 36-39.

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Based on NS2-MyEvalvid, an analysis was conducted on the effect of quantization factors upon the performance of image transmission in this paper. And by simulation, the successful transmission of the video streams grounded on Evalvid mechanism in Wireless Local Area Networks (WLAN) was achieved. A summary of the method to simulate the image transmission process of video streams in WLAN by encoding the related parameters was also provided. Furthermore, by means of changing the encoded quantization factors, the average data of the delay of image and PSNR during the transmission of video streams in multirate WLAN was got, together with a conclusion that 802.11e will guarantee a better transmission performance of video streams than 802. 11b.

Study on Performance of Information Security Risk Management

LU Zhi-gang,PAN Lin,LIU Bao-xu,XU Rong-sheng,JIANG Wen-bao

Computer Science. 2010, 37 (6): 40-42.

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Analyzed the situation and likely problems of the current risk management through affirming the current risk, combined with analysis of financing final accounts, and then put forward a systematic and normative differentiating model for the efficiency of risk management to distinguish the risk management projects from which found out the optimal one. Then pointed out the link between the investment of risk management and the loss of security incidents through further analyzing base on business, and gave out the verification of its effectiveness. The result of verification shows that this model is effective.

Genetic Projection Pursuit Evaluation Method of Network Attack Resistance Ability

WANG Hui-mei,LI Xu,XIAN Ming,WANG Guo-yu

Computer Science. 2010, 37 (6): 43-45.

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Attack Resistance best (ART) is an important security evaluation method and evaluating the system's attack resistance ability becomes a new domain of ART. Based on the security properties of the network, the network's attack resistance evaluation indexes were established from views of the goal system' s attack effect and the hacker' s cost. A projection pursuit evaluation model based on real coding based accelerating genetic algorithm was presented, and it was used in attack resistance ability evaluation for the first time. A simulation example was given,which showed that the approach was brief and effective. The approach can be used to evaluate the attack resistance ability, as well as to compare like kind attack's effect.

Role-based Access Control Model for Privacy Protection

YANG Qiu-wei,LIU Ling,LI Ken-li,TANG Zhuo

Computer Science. 2010, 37 (6): 46-50.

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Privacy preservation is a vital problem to share resource and collaboration among multi-domains. We analyzed the privacy leakage problems of current access control models, and then proposed a rolcbased access control model supporting privacy preservation. The model is based on identify-based encryption,avoiding a number of drawbacks in traditional role-based access model and making privacy preservation among multi-domains come true. Finally, we analyzed and certificated the security of the model in details by random oracle, and the model meets the IND-CCA2 mantic security. According to the simulation, the method is a practical model.

Optimization of ARQ Mechanism in Multi-hop UWB Network

WANG Ling,ZHU Guang-xi,WU Wei-min,WANG Cen-chen

Computer Science. 2010, 37 (6): 51-55.

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This paper did some researches on the ARQ mechanisms which provides the probability of involving the relay nodes into the mechanisms for ultra-wideband multi-hop wireless network,and based on the researches designed a RLC sublayer combining PWMA and Relay ARQ, which can perform as both of the end node and the relay node. Follow this,this paper made a academic analysis of the ultra wideband wireless channel models and simulated the network model under ordinary circumstances and the network model which used ARQ mechanism designed in this paper for representative two-hop wireless network,Compared the simulation results,got the conclusion that using ARQ mechanism designed for ultra-wideband multi-hop network in this paper significantly enhances the throughput and time delay characteristic of the system.

Research on Traffic-prefer-based Multi-QoS Object Decision Layered Routing

GUO Pan-hong,YANG Yang,TANG Xian-ming

Computer Science. 2010, 37 (6): 56-59.

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Based on the research background of multi-path choosing between gateways in hierarchy routing, this work exploited the guarantee method of traffic flow's specific QoS requirements and put forward some relevant policies and methods, including representation, transition and computation of traffic flows' QoS preference. On the basis of traffic flows' QoS preference, the strategy of optimal service selection was brought forward. Then, with the extension of GPSR algorithms,put forward a traffirprefer-based multi objective hierarchy routing TMQODR which is GPSR QoS Routing algorithms. The analysis on relevant performance for the algorithm has confirmed its feasibility and effectively.

Broadband Multimedia Satellite Communication System QoS Framework, Design, Simulation and Verification

FENG Shao-dong,BIAN Dong-ming,ZHANG Geng-xin,LI Guang-xia

Computer Science. 2010, 37 (6): 60-63.

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In order to provide Quality-of-Service (QoS) guarantees for multimedia services in the broadband satellite communication system,the system QoS framework was designed based on Diffserv. An integrated system design was carried out both on the satellite and the user terminals. The onboard dynamic resources assignment scheme was proposed by improving Combined Frec/Demand Assignment Multiple Access (CFDAMA). A two-stage terminal queuing and scheduling strategy was presented. The broadband multimedia satellite communication hardware in-th}loop simulation system was developed, the measurements show that our system can bearer real-time multimedia services very well.The results are similar to the real system tests.

Adaptive Rate Adjustment Mechanism for Real-time Media Streaming over MANETs

WEI Shu-jie,BAI Guang-wei,CAO Lei,SHEN Hang,WANG Hua

Computer Science. 2010, 37 (6): 64-69.

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Real-time media streaming over wireless mobile ad hoc networks (MANETs) has been an active area of research in the last few years. However, real-time multimedia delivery in such wireless environments identifies significant challenges due to both the strict QoS requirement of multimedia applications and the dynamic characteristics of wireless mobile networks. This paper proposed an adaptive rate adjustment mechanism for real-time media streaming over MANETs, i. e. ARAM. This mechanism, based on the cross-layer design, predicts the network condition according to the GM (1，1) model. On the other hand, the transmission rate is adaptively adjusted according to the predicted bandwidth and queue length. In order to evaluate the ARAM performance, we generated a set of video streams using NS2 simulation for typical network scenarios. Our statistical and mathematical analysis demonstrated that the ARAM improves the reliability of real-time multimedia delivery significantly, and provides soft QoS guarantees as well.

Trustworthy Service Scheduling Framework Based on QoS Decomposition

SUI Yu-lei,ZHOU Xing-she,FU Ning,ZHAN Tao

Computer Science. 2010, 37 (6): 70-74.

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Interoperability-centric and loosely-coupled distributed computing environment brings forward a new challenge on trustworthiness of service computing. At the same time, user puts more and more pressure on system's non-functional rectuirements such as real-time, availability, cost and so on. Therefore service' s QoS should be guaranteed trustworthily. In this paper a Trustworthy Service Scheduling Framework(TSSF) was presented to guarantee composite service's QoS requirement Fuzzy sets based trustworthy QoS decomposition model was proposed to decompose the QoS requirement of the composite service into separate ones for the atoms; and then TSSF delivers expected QoS for each atomic service with adaptive trustworthy service scheduling mechanisms based on Dynamic Service Entity Group (DSEG) ;finally experimental results indicate good performance of the proposed framework.

Research of an Efficient Power Analysis Physical Experiment Platform

LI Lang,LI Jing,LI Ren-fa,WU Ke-shou

Computer Science. 2010, 37 (6): 75-77.

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Power analysis attack has become a great threat to encryption chips. Attacks and defense of power analysis have become the research hotspot. However, experimental platform of power analysis is more difficult to build for researchers. AES encryption algorithm was used to build a high-performance FPUA-based physical experiment platform for power analysis as an example. The process of establishing the physical experimental platform was described in detail. The platform is relatively simple, fast test speed, flexibility. It will be convenient to verified for the encryption algorithm of the power. I}he efficient power analysis model was proposed. It can improve the exprimental speed in the differential statistics.

Replication Mechanism Based on Unstructured Decentralized P2P Network

HUO Lin,FANG Yi,HU He-ping,HUANG Bao-hua

Computer Science. 2010, 37 (6): 78-81.

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P2P network makes computing and data transmission efficient and convenience. Nowadays, most of studies focus on routing algorithms and structured topology of the network. However they ignore the research in unstructured decentralized P2P network's replication mechanism. We focused on the area and proposed a new mechanism called Junction Replication Method (JRM) in unstructured decentralized P2P network. With the method, we can achieve better load-balancing by reducing information flow. At last, the paper gave the pseudo code of the algorithm and proven the advantage by deduction.

Research and Implementation of Key Generation Services Compatibility Based on TCM

JIANG Min-hui,HUANG Ning-yu,ZHU Lu

Computer Science. 2010, 37 (6): 82-85.

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TPM (Trusted Platform Module) launched by TCG ( Trusted Computing Group) is the core module of trusted computing based on cryptographic technology. TPM provides asymmetric algorithm RSA to support key management scheme. Nowadays, China has raised Trusted Cryptography Module (TCM) , TCM provides asymmetric algorithm ECC and symmetric algorithm SMS4 to support key management scheme. The two chips can't be compatible, therefore the compatibility problem of key generation trusted application emerged. Through analyzing key management scheme in both TCM and TPM,as well as TCG software stack (TSS)，provided the modification scheme on TSP (TCG Service Provider) and TCS(TCG Core Services) of TSS and the scheme based on key creation flow to solve the problem of key services application compatibility.

Usage Control Model with the Ability of Character Judging

SHI Wei-cheng,TAN Liang,ZHOU Ming-tian

Computer Science. 2010, 37 (6): 86-90.

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The emphases of traditional access control studying is the policy of authorization, the studying is focus on how to distribute permissions to subject and how to restrict the using of these permissions. Based on the analysis of traditional access control, we introduced a new mode,QUCON,which is based on the UCON and has the ability to judge the character of accessing. By introducing assure obligations, unsure obligations, assure conditions, unsure conditions,characters and active rules,the QUCON has the ability to judge accessing subjectively,thereby reduce or exclude those threats from the illegal users who has permission.

IDM-ST Coding for MISO OFDM Link

LIN Pei,WANG De-sheng,ZHU Guang-xi,ZHU Xiao-dong

Computer Science. 2010, 37 (6): 91-93.

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An Orthogonal Frequency Division Multiplexing (OFDM) system with spacctimc coding Interleave Division Multiplexing (IDM) was investigated over a Multi-Input Single-Output(MISO) link.The performance of an iterative receiber structure for the proposed scheme over a quasi-static channel was evaluated via simulation.and its advantages were shown by comparison to other space-time schemes in similar settings.

Key-exchange Protocols of Cognitive Radio Based on Self-certified

ZHOU Jian,ZHOU Xian-wei,SUN Li-yan

Computer Science. 2010, 37 (6): 94-96.

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There are more security threats in cognitive radio networks than traditional wireless networks due to the strategy of opening spectrum. Switching spectrum brings time delay and interferes with network efficiency. The question also adversely effects on key-exchange protocol which is an important part of key agreement, and gives malicious nodes the attack chance. So this paper put forward a new method, firstly cognitive radio network was divided into multiple clusters, secondly used protocol the time delay of switching channel to select the optimal path with traveling salesman problem in cluster and built the optimal multicast routing tree among clusters; at last different key-exchange protocols based on self-certified were used in cluster and among clusters, which can prevent active attack and passive attack, authentication and key agreement can also simultaneously carried out. The efficiency of protocol is O(2m),m is the number of cluster.

Transmission Distance Controlling Method of Wireless Sensor Networks

YIN Zhen-ling,WANG Ru-chuan,HUANG Hai-ping,SUN Li-juan

Computer Science. 2010, 37 (6): 97-101.

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In the case of the restrictions of energy on wireless sensor nodes,how to reasonable routing protocol of adaptive topology change and control research fields.Based on RSSI ranging technology,this novel introduced and compared three transmission distance control strategies,which utilizes time-delay and energy-comsumption as the reference index.Simulation results show that,choosing transmission radius dynamically can obviously improve the whole performance of the system,prolong the lifetime of the network and decrease the energy consumption and time delay of the sensor nodes.

Reliability Evaluation of the Network Storage System Based on Block Diagrams

ZHANG Ying,ZHANG Yi,WANG Ji-lu

Computer Science. 2010, 37 (6): 102-105.

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With the rapid growth of information and improving data security requirements, the reliability of network storage system directly affects the information system performances. This paper focused on network storage system's equipment failure. Based on the reliability analysis about the typical model of network storage system and the use of reliability block diagrams theory, the paper proposed a hybrid form of network storage system reliability analysis and evaluation methods, including system reliability block diagram analysis methods based on nodes attribute, M value methods with the business load. And the hybrid structure of FC-SAN systems experiment was established to verify the effectiveness of the method. As a result of this method compared to other methods of testing with a simple, time-saving, low cost,it is more conducive to application of network storage system to optimize the scheme and equipment.

Reliability Analysis of star Network with Link Failures

LIANG Jia-rong,HUA Ren-jie

Computer Science. 2010, 37 (6): 106-110.

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Reliability problems on star interconnection network regarded as one of important candidates of network models in largcscale processor systems have been being concerned by people. Under probability model based on link reliability, reliability of star network was analyzed by different analysis methods, and reliability models that correspond to those different methods were set up. The constraint relation between link reliability and network reliability was indicated by above reliability models. The results of simulation experiments show that under existing massive integrated circuit technology, these analysis methods on reliability are all feasible and reliability of star network can be controlled within a ideal scale.

Study on Distribution Mechanism of Pervasive Computing Based on Wireless Sensor Networks

HUANG Xiao-sang,WANG Ru-chuan,YE Ning

Computer Science. 2010, 37 (6): 111-113.

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In the pervasive computing environment based on wireless sensor networks,as a result of nodes moving,the message distribution mechanism is no longer applicable.After analyzing the distribution of message influencing factors,it was found that the virtual grid can be used as the shortest path for message distribution.In the article,the new problems were also discussed that this mechanism will face when the source node moves.Therefore with simulation analysis,the feasibility of the distribution mechanism proposed by this paper was verified.

Network Attack Model Based on Ontology and its Application

WANG Qian,FENG Ya-jun,YANG Zhao-min,YAO Lei

Computer Science. 2010, 37 (6): 114-117.

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The paper, which is based on attack theory, presented an architecture of multi-dimensional attack classificalion. According to attack classification, attack ontology model was built, and the logical relationship and hierarchy struclure between the ontology of attack concepts were described. Finally according to attack scenario based on atomic ontology of attack, the attack on the target was realized.

Strategy of UDDI Superpeer Configuration Based on Vertex Weight Priority

ZHOU Ming-qiang,WANG Dong,LI Shuang-qing,HU Jun,ZHU Qing-sheng

Computer Science. 2010, 37 (6): 118-121.

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Web server registration(UDDI) is an important part of the SOA. To solve the Single Point of Failure and its expansibility in UDDI, the researches proposed some solutions such as the Affiliate Registry and Peer-to-Peer, but their effects do not meet the need. By selecting a server-node at dense network area,the papar proposed a new model SPSR-UDDI (Super Peer and Semantic Routing UDDI). The connection between nodes will be dynamically adjusted by the principle of vertex weight priority, which makes that whole time of server response be the shortest. The paper built a model of network evolvement to achieve network's self-organized evolvcment process. The paper gave our experiment results that validate the validity of new strategy.

Intrusion Detection Algorithm Based on Simulated Annealing and K-mean Clustering

HU Yan-wei,QIN Zheng,ZHANG Zhong-zhi

Computer Science. 2010, 37 (6): 122-124.

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Intrusion detection algorithms based on K-mean clustering have sensitive dependence on initial value and are easy to fall into local extremum.To solve this issue,a new intrusion detection scheme was presented by combing Simulated Annealing and K-mean clustering.The proposed algorithm usesSA to optimize the clustering pattern in the clustering analysis.It can achieve global optimization and better accuracy of the intrusion detection system.Moremover,parallelism of SA greatly quickened the convergence rate.Experiments were completed on KDD Cup 1999,and the results show that presented scheme has lower time consume,false positive rate,and false negative rate cimpared with intrusion detedtion systems based on K-mean clustering.

Publicly Verifiable Secret Sharing Scheme with Proactive Ability

CHEN Yang-kui,YU Jia,HAO Rong,LIU Hong-yan,XU Yue-bin

Computer Science. 2010, 37 (6): 125-127.

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A publicly verifiable secret sharing(PVSS) scheme is a special secret sharing scheme in which the shares distributed by the dealer can be verified not only by shareholders themselves but also by any other party. However, in a normal publicly verifiable secret sharing scheme, an adversary may get the secret by attacking threshold shareholder servers for a long time. In order to deal with this problem, a publicly verifiable secret sharing scheme with proactive ability was newly proposed, which not only can publicly verify the validity of shares, but also has the property of periodically renewing shares. This makes the proposed scheme more secure than other common publicly verifiable secret sharing schemes, and makes it better satisfy security demand of various applications.

Flexible and Practical Scheme to Preserve Confidentiality of Sensitive Attributes in Digital Certificate

LIAO Jun-guo,LING Le-zhen,ZHU Bin

Computer Science. 2010, 37 (6): 128-130.

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In open environment, digital certificate is used in identity authentication and authorisation rrmnagement. Digital certificate often includes sensitive attributes, so the research on preserving confidentiality of sensitive attributes in digital certificate becomes concerned. This paper presented a flexible and practical scheme to preserve confidentiality of sensitive attributes in digital certificate, and analysed its security and performance. In the scheme, the different sensitive attributes in digital certificate are encrypted with different sub-keys generated from a main key. The scheme has some characteristics as follows; selectively disclosing sensitive attributes in digital certificate, simple key management, and low time cost. Based on X. 509,the presented scheme was implemented.

Practical Interconnection Network RPC(k) and its Routing Algorithms

XING Chang-ming,LIU Fang-ai,YANG Lin

Computer Science. 2010, 37 (6): 131-135.

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Peterson graph has good performance in parallel and distributed computation because of its characteristics such as short diameter and regularity. Based on ring structure, a new extension of Peterson graph was proposed, and a new interconnection network, the RPC(k) network was developed. Additionally, the properties of the RPC(k) network were investigated. It was proved that RPC(k) has lower-degree connectivity, smaller network diameter, simple topology and good extensibility. On the basis of these analysis, the conditions satisfying that the network diameter and grouping ability of RPC(k) are better than the diameter and grouping ability of 2-D Torus and RP(k) interconnection networks were presented. Finally, based on the RPC(k) network we designed a set of routing algorithms which are point to-point routing, permutation routing,one-to-all routing and all-to-all routing. Their communication efficiencies are「k/2」+5,k+9,「k/2」+5 and k+9 respectively. Especially as the k increasing, the efficiencies of these routing algorithms based on RPC(k) approximate to 1/3 of which based on RP(k) network.

Design of Embedded Wireless Sensor Netowrk Platform Based on uC/OS-II

WANG Feng,WANG Jian,GUO Zhong-wen

Computer Science. 2010, 37 (6): 136-141.

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Design and realization scheme of sensor-node and sink-node in soft and hard were proposed based on the introduction of its system structure,characteirstics and function.This papers deeply researched characteirstice and kernel of the embedded RTOS uC/OS-II,and transproted the uC/OS-II successfully to the controller Nios.The mini type-TCP/IP protocol stack LwIP Realization of LwIP on uC/OS-II was introduced.

Research on an Adaptive Service Discovery System for MANETs

WENG Hai-bin,WEN Yuan-feng,JIN Bei-hong,ZHANG Biao

Computer Science. 2010, 37 (6): 142-146.

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Service discovery systems over MANETs have to face node's frequently movement, random joining or leaving, and services revoked by their owners, therefore it is a big challenge to find available services at a reasonable cost.In order to meet above challenges and improve the adaptability of the system, we proposed a system SCN4M-DL, which adopts directory-less architecture. Coupling with underlying geographical routing algorithm,we designed and implemented a ring-based service register and discovery mechanism, which leads to high success rates of discovery rectuest and also can efficiently control memory costs and network traffic. The experimental results show that SCN4M-DL can adapt well to MANETs' characteristics and the changes of service states.

Research on Isolation Semantics Description Based on Noninterference Theory and Automated Isolation Strategy Verification Scheme

CUI Jun,HUANG Hao,CHEN Zhi-xian

Computer Science. 2010, 37 (6): 147-154.

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Processes or modules isolation helps protect information from being revealed or modified and prevent processes or modules from passing error or failure to others. We proposed the semantics of isolation by noninterference theory,for the purpose of analyzing and designing isolation strategies in software systems;we also specified the semantics of isolation and its determine conditions by Communicating Sequential Process(CSP) in order for automated formal verificanon of isolation strategics in systems in formal verification tool FDR2. And in this paper, with an example of file system monitor in a virtual machine, we illustrated how to specify a system or a isolation strategy by CSP formulation and how to verify given isolation strategics in a system automatically in FDR2.

Full-automatic Detection of Memory Safety Violations for C Programs

YANG Yang,ZHANG Huan-guo,WANG Hou-zhen

Computer Science. 2010, 37 (6): 155-158.

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Symbolic execution is an effective and automatic bug-finding method. But symbolic execution is limited in practice by the computation cost and path explosion. We presented a tool for full-automatic detection and generating inputs that lead to memory safety violations in C programs, including buffer overflow, buffer overrun and pointer dereference error. In order to reduce the amount of symbol variable, we used the symbol variable to track the length of buffer and C string. The use of symbolic buffer length makes it possible to compactly summarize the behavior of standard buffer manipulation functions. While resolving the problem of path explosion, we introduced the dynamic slicing methods to prune the redundant paths. It's shown by the experiments that our method presented in this paper not only is feasible but also has little cost.

Study of Test Case Generation for Web Applications

PENG Shu-shen,GU Qing,CHEN Dao-xu

Computer Science. 2010, 37 (6): 159-163.

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Along with the fast evolution of Internet, Web application development has become one of the main categories of software application development,and Web application programs have become more and more complicated. Improving the duality of Web applications from different aspects is inevitable task of Web application developers. An important way of ensuring the quality of Web applications is software testing, the core work of which is test case generation. In this paper, we classified the methods for Web test case generation into four categories; Capture/Replay, HTML analysis, Source code analysis, and User-Session analysis. We discussed these four methods in detail, and concluded general steps of generating test cases in these methods. Finally, we listed the advantages and disadvantages of the four method categories,and compared their performance from various perspectives, including the effort needed to implement the method, maximum attainable code coverage, and so on.

Research on Thin-client Oriented Web Operating Systems

REN Yi,GUAN Jian-bo,YIN Hu-zhe,WU Qing-bo,DAI Hua-long

Computer Science. 2010, 37 (6): 164-167.

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With the development of distributed computing technologies, browser-based Web operating system (WebOS) came into being. It provides mechanisms for integrating services and resources on the Internet. And it makes services and resources available for online users regardless of where they are and when it is. WebOS represents a trend towards future use of thin client based Web applications. It has become one of the most important patterns of utilization in the coming cloud computing era. We first introduced the concepts and structure of WebOS. Then we analyzed related work and the trends of WebOS. And we also discussed the technical factors which cumber the development of WebOS. Finally,we made comprehensive research on EycOS, which is a typical open source WebOS. We analyzed EycOS's structure and APIs. hhen we extended its functions by implement a SOAP-based hravel service.

Dynamic Integration of Disparate Services and Distributed Data

PENG Shu-qing,CHEN De-yun

Computer Science. 2010, 37 (6): 168-170.

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It is very important for enterprises to utilize resources efficiently inside and outside in order to improve the efficiency. A new framework that services and data are composed dynamically based on enterprise service bus(ESB) was proposed, in which business process was analyzed into service-data flows and the weight computation method was used for evaluating the separating rationality. Dynamic routing mechanism was applied to map abstract service to service proeiders and map abstract data to datasources. Abstract service description table (ASDT)，abstract service mapping table (ASMT),abstract data description table (ADDT),and abstract data mapping table (ADMT) were modified by service data muter for solving the conflicts. Finally, the method has also been applied in Yunzheng System of Hcilongjiang Province,in order to prove it's feasibility.

Static Analysis of Memory Leak Fault

YE Jun-min,WEI Peng,JIN Cong,WANG Jing-hua,ZHANG Qing-guo,ZHANG Wei

Computer Science. 2010, 37 (6): 171-175.

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Recent researches detect memory leaks mainly through static test methods. The basic idea is to detect memory leaks by designing specific algorithm based on the control flow graph of program to be tested, but the limitations of these methods are that control flow graph doesn't contain useful information for further use, so that designed algorithms can't detect memory leaks efficiently. We defined a control flow graph for detecting memory leaks and proposed control flow graph reachable paths generating algorithm to detect and analyze memory leaks for generated paths. This method was proved by experiments to be very effective.

Research Based on a Method of CFCM Clustering Intrusion Detection

ZHAO Yue,ZHANG Wei-qun

Computer Science. 2010, 37 (6): 176-178.

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Clustering Web flows to attain Load Balancing is widely used in Clustering Intrusion Dtection approach.Correlated ideas were improted in the traditional fuzzy C-means clustering algorithm (FCM),defined logical distance formula,and presented a Correlated fuzzy C-means clustering algorithm(CFCM).At last we applied this approach in Clustering Intrusion Detection approach,and used KDD Cup 1999 data set to do experiment.The results demonstrated the viability and effectiveness of our approach.

Novel Approach for Extracting XML Schema Definition Based on Content Model Graph

NING Jing,LIU Jie,YE Dan

Computer Science. 2010, 37 (6): 179-185.

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Although XML Schema can be used to perform validation,querying and transformation on XML documents,a lot of XML documents in real applications have no XML Schema defined. This paper presented an approach, XSDInfer, to extract XMLSchema Definition (XSD) from XML documents automatically. Firstly, schema information harvesled from XML parsing was merged into the Content Model Graphs by applying rules. Then the graphs were transformed to content model expressions to generate the XSD. XSDInfer can scale to very large and deep recursive XML documents. It supports the context sensitive content model, and the generated XSD is more human-readable. Experiments show that XSDInfer achieves better performance both in scalability and expressiveness in contrast to the previous techniqucs.

Mining Closed Composite Sequential Patterns Efficiently

YAN Lei-ming,SUN Zhi-hui,ZHANG Bai-li,YANG Ming,YAO Pei

Computer Science. 2010, 37 (6): 186-190.

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Sequential pattern mining has been an essential mining task and an active research area in recent years. However, existing sequential pattern mining algorithms are designed for closed itemsets or simple closed sectuential patterns,and can hardly extract composite sequential patterns, an important class of patterns consisting of several short segments separated by gaps. An efficient algorithm for mining frequent closed composite sequences with any number of segments of different lengths, CloCSP, was proposed. It adopts a novel composite strategy called Mixed Composite, which not only can produce all of closed composite sequential patterns, but also can efficiently prune the composite space and simultaneously check the sequential patterns closure, accordingly reduces the cost in both runtime and space usage. Experiments on both synthetic and real data have demonstrated that CloCSP can significantly discover all of closed composite sectuential patterns.

Storage Optimization for Continuous Query over Sliding Window Based on Ladder Queue

TANG Xiang-hong,LI Guo-hui

Computer Science. 2010, 37 (6): 191-195.

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Query processing optimisation based on update pattern awareness is a new hot topic in the research field of continuous queries over sliding window. Efficiency of continuous query processing highly depends on overhead of result state maintenance. This investigation proposed a ladder ctueue with branch lists to maintain result state of continuous query. The trunk list and the branch list were designed into the ladder queue. The ladder queue used the branch lists to gather the result tuples with the identical expiration time,and employed "spawning" mechanism to achieve O(1) amortined access time complexity for result data under the different distributions. Our experiments showed that the new ladder queue can improve the performance of query processing greatly and outperforms other data structures.

Evaluating Model of Cache Miss in the Filtering of XML Data

SHEN Jie,YIN Gui-sheng,WANG Xiang-hui

Computer Science. 2010, 37 (6): 195-199.

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One of the most important factor in the data-intensive system(ig. XML filtering engine) with memory resident is hardware cache behavior. Now, the popular researches in XML filtering are based on the automata to express the XML query. In this paper, we studied the cache performance of XML filtering based on the automata by the analytical modeling and system measurement, and estimated the cache miss in the infra-round model and inter-round model instead of the general estimation in the cache. Our results show that our estimation engine has more accuracy.

Ontology-based Natural Language Interface to Relational Databases

LI Hu,TIAN Jin-wen,WANG Huan-huan,SHI Yong

Computer Science. 2010, 37 (6): 200-205.

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This paper proposed an approach to creating an ontology-based natural language interface to relational databases which allows end-users to access and query information in database with a natural language. In order to strengthen the reliability and the user-friendliness of the system, our approach integrates WordNet as the base lexicon and ontology as the knowledge base of the semantic interpreter. The user inputs will be first translated into a syntax tree by syntax analysis and parsing, then it will be translated into an intermediate expression language DRS by the ontology-based semantic interpreter. The SQL generator transfers DRS expressions into SQL sentences by a template technictue. The DBMS executes SQL sentences and returns the final result.This paper presented the framework based on ontology technictues to implement portable NLIDBs that makes it easier to migrate from one domain to another. The prototype system and our experiments show that our approach has generated good results with excellent performance on common queries.

New Spatial Query Language Based on GIS

XU Cheng-zhi,Phillip SHEU Chen-yu,QIAN Tie-yun

Computer Science. 2010, 37 (6): 206-210.

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At present, the mainstream of spatial query languages are extended from SFA SQL or SQL/MM Spatial,two international standards. All these two standards for spatial query and spatial analysis are function style. When search conditions increase,function style language will become too complex to be used by normal user, and too inefficent to execute. In this paper, a new spatial query language, Semantic Query Description Language for Geography (SQDL-G)，based on GIS was proposed. The language converts spatial predicates into spatial operators and introduces sulrquery structure. An execute engine of this language was built up based on ArcGIS platform. Experiments showed that this language has an expression of a flexible, clear structure, and easy to user acceptance.

Research of Personalized Methods of Information Retrieval

WANG Jun-yi,YE Xin-ming

Computer Science. 2010, 37 (6): 211-213.

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Personalization to information retrieval is very useful in information retrieval, the user profile can be used to represent the favorites or interests of an user. Many approaches to personali}ation have been studied in expanding query with user profile. We proposed a navel method which use the context of long-term user profile with multiple-domain to expand query model under the unigram language modeling framework, uses the new query model to retrieve and get more interesting results for users. Then combined with psudo-elevance feedback model, the method get better performance. Experimental results show that the proposed method is effective.

Research on Null Values in Probabilistic XML Database

ZHOU Zhi-zeng,WANG Xin-jun

Computer Science. 2010, 37 (6): 214-216.

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Uncertainty and Incompleteness are a real-world challenges of the database. The combination of NULL value and probabilistic XML database can better deal with data, but also increase the complexity of the database. We proposed two interpretation what means the null value in the XML probabilistic database, one of them can generate probabilistic interval,so we presented a compromise solution to the probabilistic interval problem in probabilistic XML database with NULL value. Finally, we proposed an Nth moment method for anglicizing probabilistic database comprehensively.

Study on Delegation Revocation in Attribute Supported Delegation Model

YE Chun-xiao,FU Yun-qing

Computer Science. 2010, 37 (6): 217-219.

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In Attribute Supported Delegation Model (ABDM) , dclegatee must satisfy both delegation prerequisite condilion (CR) and delegation attribute expression (DAE) when assigned to a delegation role. In AI3DM, revocation focuses on how to revoke those delegated roles or permissions from delegatee. This paper first introduced two new sorts of revocations,which bring about priority between multi step delegation and revocation. hhen analyzed the relation between delegation and revocation and proposed two solutions; "first rectuest first response" and "revocation first then delegalion". We also discussed different situations fitting these two solutions.

Application of Hypergraph in Data Mining

CUI Yang,YANG Bing-ru

Computer Science. 2010, 37 (6): 220-222.

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The development of data mining is tightly related to the application of new theories and methods. Definition of hypergraph is based on Graph Theory and Set Theory, and has been used in data mining recent years. Some important concepts of hypergraph were given at first. Then the application on Maradbcm algorithm, clustering and spatial data mining was introduced.

Evaluation of the Scoring Policies in National Admission and Examination of Colleges and Universities Using Data Warehouse and OLAP

CAI Hai-min,ZHANG Zi-li,ZENG Zheng,YIN Yuan-fen

Computer Science. 2010, 37 (6): 223-225236.

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National Admission and Examination of Colleges and Universities (NAECU) gets in closer and closer touch with the national economy and the people's livelihood. hhe Scoring Politics in NAECU arc becoming one of key issues of the Provinces and Cities Admission Offices (PCAO) , and attract the attention of every examinee as well as the whole society. Currently there is no systematic and scientific way to evaluate the Scoring Policies. ho this end, data warehouse and OLAP technology were employed to analyze the data accumulated in the past years in a province. I3y multi dimensional analysis of the data, some interesting results were found and presented in the paper. Based on these findings, the evaluation scheme for Scoring Policies in NAECU was then given. hhis scheme can provide decision making support when introducing new scoring policies.

Improved Collaborative Filtering Recommendation Algorithm

WANG Qian,WANG Jun-bo

Computer Science. 2010, 37 (6): 226-228243.

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When searching the nearest neighbor set, the traditional collaborative filtering algorithm ignores the impact of the time factor, only from the user or item takes into account the similarity of the user or item unilaterally, and ignores the impact of user characteristics on recommendation. Aiming to the above problems, we introduced the time forgotten function, resources viscosity function and the user feature vector, and improved the process of finding the user's nearest neighbor set, reflected the time effect, degree of user preferences and user characteristics, and tested this new methodology on data set got from MovicLens. I}hc results of experiment show that proposed method can improve the accuracy of the prediction.

MPI Runtime Parameters Tuning Based on Neural Network on Multi-core Clusters

WANG Jie,ZENG Yu,ZHANG Jian-lin

Computer Science. 2010, 37 (6): 229-232.

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The new features of multi core add the optimization space for MPI applications, and besides tuning MPI runtime parameters is a common practice perceived to optimize the MPI application performance. However, the best configuration of the runtime parameters not only depends on the underlying architecture of a specific multi-core cluster but also on the features of MPI application. We constructed and analyzed an effective tuning model bases on artificial neural network to automatically predict the near-optimal configuration of runtime parameters for any unseen input programs under the current multi-core cluster. Experimental results from two different benchmarks were presented to show effectiveness of our approach. We observed that the speedup gained by the predicted runtime parameters can averagely achieve 95% of the speedup gained by the best parameters configuration.

Novel Approach of Ontology Mapping Extraction SME

XIA Hong-ke,ZHENG Xue-feng,HU Xiang

Computer Science. 2010, 37 (6): 233-236.

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Ontology mapping is the foundation of semantic query and semantic integration based on ontology. As the crucial point of ontology mapping, the task of mapping extraction is to find whether there exists the ontology mapping among the similarities between source ontology and target ontology. In this paper the problem of mapping extraction was regarded as the problem of set covering, and a novel ontology mapping extraction algorithm based on set covering SME (SCM-based Mapping Extraction) was proposed, by which the property set that covers the training data set in maximum degree was searched during training stage, and the mapping extraction was carried out by means of the conjunction of the properties of property set in testing data set during testing stage. Experimental evaluations show that this method has better comprehensive performances compared with other algorithms.

Story Link Detection Research Based on the Dynamic Extraction of Correlative Word

ZHAO Hua,DENG Pan,ZHANG Jian-wei

Computer Science. 2010, 37 (6): 237-239270.

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Story link detection is a task of topic detection and tracking, which is to detect whether two stories arc "linked",or discuss the same event This paper proposed a story link detection method based on the dynamic extraction of correlative word. Correlative word is defined to be a pair of words that satisfy certain Relation Restriction. In this paper, relation restriction refers to a set of features. hhis paper explored three features, which include the initial letter, locanon and window. The more two stories had the same correlative words, the larger similarity they had. Experimental results showed that the story link detection method based on the dynamic extraction of correlative word performs very well, which testifies the great capabilities of this method. We also find that relation restriction is critical to the performance of this method.

Improved Virus-evolutionary Genetic Algorithm Based on Fauna Structure

GU Min,YANG Feng

Computer Science. 2010, 37 (6): 240-243.

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An improved virus evolutionary genetic algorithm based on fauna structure was proposed in this paper. The host population is consisted of a father and several mothers and several bachelors. Crossover is occurred between the father and the mothers to produce offspring. Mutation is occurred among the bachelors to produce offspring. Virus is divided into big virus and small virus. In the previous iteration, big virus works and in the latter iteration, small virus works. The instances verified that the improved virus-evolutionary genetic algorithm outperforms the tradition virus-evolutionary genetic algorithm.

Analysis of Profit for Internet Service Provider Based on Multipath Inter-domain Routing

LI Dan,WANG Bin-qiang,YIN Ting,MA Hai-long

Computer Science. 2010, 37 (6): 244-247.

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The multipath inter-domain routing is a complex topic, but profits of Internet Service Provider(ISP) are one of the most important factors for the prospect. We established an optimization model for profit of ISP based on the user's utilities. Then, the incensement of profit from singl}path routing to multipath routing and the impact of relevant factors were analyzed. Through theoretical analysis and simulation experiments,we found that ISP can acquire more profit when multipath routing was deployed. Moreover, it can offer better service for more users and delay sensitive traffics.

Approaches for Incrementally Updating Approximations under Characteristic Relation-based Rough Sets While Attribute Values Coarsening and Refining

LIU Wei-bin,LI Tian-rui,ZOU Wei-li,HU Cheng-xiang

Computer Science. 2010, 37 (6): 248-251.

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An incomplete information system is a generalization of an information system, which has wide applications in many domains. The approximations of concepts may vary when the information system is dynamically changing. It is meaningful to study how to update the approximations by using the original information. `hhe dynamic changes of information systems can be considered in the three aspects:the coarsening and refining of attribute valucs,the attribute set and the object set, This paper only focused on the approaches for updating approximations when coarsening and refining attribute values. The definitions of attribute values coarsening and refining in the incomplete information system were given. I}hen approaches for updating the approximations were discussed when coarsening and refining attribute values under the characteristic relation. Finally, several examples were given to illustrate the validity of the proposed approaches.

Multi-robot Mission Planning Algorithm and its System Implementation

YU Ling-li,JIAO Ji-le,CAI Zi-xing

Computer Science. 2010, 37 (6): 252-255.

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We proposed a centralized ant colony planning approach for multirobot mission planning problem. The task allocation model and route planning model of ant colony algorithm description were built, meanwhile, local search strategy was utilized to improve ant colony algorithm assignment effect. At last, we achieved a centralized multi-robot mission planning system for experiments analysis. The results show that ant colony algorithm can solve the multi-robot mission planning problem effectively,and provide a new idea for multi-robot coordination mechanisms.

Novel Hierarchical Immune Algorithm for TSP Solution

WU Jian-hui,ZHANG Jing,ZHANG Xiao-gang,LIU Zhao-hua

Computer Science. 2010, 37 (6): 256-260.

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In order to solve traveling salesman problem more efficiently using artificial immune algorithm, a two-floor model based on multiple sub-populations immune evolution as well as hierarchical local optimization immunodominance clonal selection algorithm(HLOICSA) was put forward. I}o quickly obtain the global optimum,multiple sulrpopulations were operated by bottom floor immune operators:local optimization immunodominance, clonal selection, antibody diversity amelioration based on locus information entropy, multiple sub-populations were also operated by top floor genetic operators; selection, crossover, mutation. I}hrough those operators, diversity of antibody sulrpopulation distribution and excellent antibody affinity maturation was enhanced, the balance between in the depth and breadth of the search-optimizing was acquired. Experimental results indicate that the algorithm has a remarkable quality of the global convergence reliability and convergence velocity.

Text Sentiment Classification Research Based on Semantic Comprehension

WEN Bin,HE Ting-tingL,LUO Le,SONG Le,WANG Qian

Computer Science. 2010, 37 (6): 261-264.

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Text sentiment classification is used widely, such as information filtering, information security and information recommendation. This paper proposed an improved method based on semantic comprehension. In this paper, sentiment primitive was introduced into sentiment terms identification, and then semantic values of phrases were obtained.Furthermore, this paper further analysed adverbs and its influence on identification of text orientation in the semantic level and achieved the text sentiment classification. I}he experimental results show that the proposed approach is suitable for judging sentiment orientation.

Rules Reduction for Decision Table Based on Cloud Model

DAI Jin,HE Zhong-shi

Computer Science. 2010, 37 (6): 265-267.

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Through decision table transformation, the rules were mapped to cloud vectors. The equivalence relations betwecn the rules were reckoned using the similarity between the cloud vectors' digital characteristics. On this basis, a rules reduction algorithm for decision table based on cloud model was proposed. It not only resolves the problem that the ectuivalence relation based on rough set theory doesn't distinguish the similar relationship because it requires matcking strictly each attribute, but also overcomes the shortcomings that the equivalence relation based on fuzzy set relics on the priori knowledge and considers inadequate to the random distribution of attributes. Experiments show the algorithm has high performance.

Improved Particle Swarm Algorithm Based on Arnold Map

WANG Jun-hui

Computer Science. 2010, 37 (6): 268-270.

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Particle swarm optimization is one of the heuristic global optimization algorithms, which has attracted vast attendons of researchers. Based on the analysis of the current improved algorithm, one improved algorithm was proposed in this paper, which employs Arnold chaotic map and one dimension disturbance term to improve the particle swarm algorithm. In the proposed algorithm, the researching ability of global optimization of particle swarm is enhanced through the improving of single particle. The simulation results show that the algorithm can keep the populations diversity better, and the performance of the particle swarm is increased notably.

Communicating in Resource-constrained Multi-Agent Systems

ZHAO Jie,YANG Liu,LI Shu-ping

Computer Science. 2010, 37 (6): 271-272.

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Agents with partial obscrvability need to share information to achieve decentralized coordination. However, in resource-constrained systems,indiscriminate communication can create performance bottlenecks by consuming valuable bandwidth. Therefore, there is a tradeoff between the utility attained by communication and its cost. Here we addressed this tradeoff by developing a novel strategy to make communication selective based on information redundancy, ensuring communication only occurs when necessary, while maintaining acceptable coordination.

Psychological Analysis of Trends Intelligent Network Model

JIN Yu-chang,QIN Qi-wen,AN Jun-xiu

Computer Science. 2010, 37 (6): 273-277.

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Network groups arc a virtual gathering but real group phenomenon with the rapid expansion of Internet users. Because of the Internet privacy and freedom, the Internet community can more really represent their own point of view aiming at a thing phenomenon. Psychological hrcnds Network is a comprehensive psychology, cloud computing, information retrieval,natural language processing,statistical theory and methods such as multi-disciplinary design of the intelligent model. Constructed the program flow at the core of the network group model of intelligent analysis of psychological trend in architecture, breaking the data stream programs to address the cloud computing model software hottleneck. Further researched the design and realization of the core module in intelligent analysis model structure. And the college students Internet Group's 30000 texts were used to test the model, the test showed that the model can efficiently realize the psychological trend of population characteristics of the network, give the user a real feelings through the cloud and the structural equation model.

QPSO-based Multi-instance Learning for Image Annotation

LI Da-xiang,PENG Jin-ye,BU Qi-rong

Computer Science. 2010, 37 (6): 278-282.

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In most existing training data set for image annotation, keywords are usually associated with images instead of individual regions, so it is difficult to use supervised learning methods for image annotation. In this paper, based on quantum-behaved particle swarm optimization algorithm(QPSO) , a novel multi instance learning (MIL) algorithm was presented( QPSO-MIL)，we formulated image annotation as a supervised learning problem under Multiple-Instance Learning framework. This algorithm regards every image as a bag, and the feature vectors of the segmented regions in this image as instances. We defined a fitness vector for each particle based on the diversity density(Dl)) function. In the instance feature space we used QPSO to search the global maxima of DD function in each dimension simultaneously, and took the result as a concept point of the keyword,finally assigned corresponding key words to a test image according to the Bayesian maximum a posteriori probability criteria. Experimental results on ECCV 2002 data set indicated that the QPSO-MIL method is effective.

Fast Algorithm for Multi-frame Selection with Jointly Optimization of Fractional Pixel Motion Estimation

LU Ji-yuan,SUN Shao-hui,CHAO Hong-yang

Computer Science. 2010, 37 (6): 283-285.

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Multi-frame and fractional pixel motion compensation technology improve the video coding performance at expense of the high memory consumption and computational complexity. We proposed a jointly optimized algorithm for these two technologies by analyzing the connection between them. Firstly, the composed MVs were used to select the candidate reference frame set. Secondly, fractional pixel motion estimation was only applied on the reference frame which has the optimal predicted residual based on a two-dimension polynomial model. According to our experiments, a reduction of 60% execution time is attained while still maintaining the same R-D performance with H. 264 Joint Model(JM).

Face Recognition Using Kernel Maximum Scatter Difference Discriminant Analysis

DU Hai-shun,LI Yu-ling,WANG Feng-quan,ZHANG Fan

Computer Science. 2010, 37 (6): 286-288.

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An efficient nonlinear subspace learning method, kernel maximum scatter difference discriminant analysis (KMSI),was proposed for face recognition in this paper. The main idea of KMSI)is to map the input sample data into feature space by nonlinear function, and then adopt maximum scatter difference discriminant analysis(MSD) to find the solution in feature space by kernel trick. The experimental results on the Yale and ORL face image database show that the proposed KMSI)method for face recognition has higher recognition rate and more effective.

Anomaly Detection Method Based on Random Field for Hyperspectral Imagery

DU Bo,ZHANG Liang-pei,LI Ping-xiang,ZHONG Yan-fei,CHEN Tao

Computer Science. 2010, 37 (6): 289-292.

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This paper presented an anomaly detection method based on random field model in order to introduce the spatial information between the neighborhood pixels in the hyperspectral imagery into the anomaly detection procedure and reduce the area for detection. In our method, the pixels' neighborhood relationship in the hyperspectral imagery was described by the Random Field model. I}hen this neighborhood relationship information between pixels was introduced into the local-region anomaly detector which uses a nested dual window to detect probable anomaly pixels. Experiments show that this method performs better than the traditional RX-algorithm, especially for the larger anomaly targets which usually contains several neighborhood pixels and with better efficiency.

RapidIO User-level Communication Interface Realization Based on RDMA

JI Ying-hui,ZHANG Jian-dong,CAI Wei,CAI Hui-zhi

Computer Science. 2010, 37 (6): 293-296.

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As a high performance interconnect protocol in embedded system,RapidIO promises a better performance by taking advantage of Remote Direct Memory Access operations. At present, the only accessible RapidIO communication interface is Ethernet simulator, which limits the communication performance of RapidIO. In accordance with the characte-ristics of RapidIO protocols,this paper put forward a RapidIO user-level communication interface based on RDMA by making reference to the various methods of communication protocols based on RDMA at home and broad. After that,the author validated the performance of this communication interface, and made its implementation to achieve optimizalion through various ways. I3y comparison, this RapidIO user-level communication interface is known to gain the highest throughput in all the present Rapidl0 communication interface.

Research on Row Buffer Hit Prediction for Memory Access

WANG De-li,GAO De-yuan,WAND Dang-hui,SUN Hua-jin

Computer Science. 2010, 37 (6): 297-302.

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Memory system becomes a bottleneck for the overall computer system performance. This paper reduced the average memory access latency using the characteristics of DRAM. Firstly, the control strategy for memory row buffer was studied. Secondly,a Read and Write Separated Predictor (RWS) for page mode prediction was proposed,a two saturated counter and a two level predictor to realize RWS were also proposed. Finally, a simulation platform based on SimpleScalar was constructed to evaluate the proposed predictors. The result shows that compared with CLOSE strategy, the average memory access latency is reduced about 26%, the average IPC speedup is about 4. 3 %. It is also shown that the average memory access latency is reduced about 19. 6%，the average IPC speedup is about 2. 5% Compared with OPEN strategy.