Computer Science

Survey on Image and Video Painterly Rendering

HUANG Hua,ZHANG Yu,ZHANG Lei

Computer Science. 2011, 38 (6): 1-6.

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Image and video painterly rendering is an important problem in Non-Photorcalistic Rendering (NPR)，which has various applications in many fields, like cartoon animation, digital entertainment, etc. This paper reviewed the development of painterly rendering, whilst some typical approaches were investigated and classified, and the characteristic of each technique was fully analyzed. Based on this,some challenges and possible directions in the domain of image and video painterly rendering were discussed for reference.

Overview of Anomaly Detection Based on Program

HUANG Jin-zhong,ZHU Miao-liang

Computer Science. 2011, 38 (6): 7-13.

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In terms of methods describing normal program behavior, anomaly detection based on program can be grouped into several broad categories; specification-based, frectuency-based, control-flow-based, and data-flow-based. After reviewing systematically the basic ideas and various models used in these approaches, discussing the new advances of the technique, pointing out and analyzing some problems and weaknesses which exist in current research, this paper formulcted a notion that anomaly detection based on program should focus attention on various server programs. A system prototype based on the hierarchical structure of server programs' traces and validated by a preliminary experiment was simply introduced. The prototype is capable of analyzing anomalous events and providing detailed information with resped to intrusion,and these abilities are just the trend for more research of anomaly detection.

Survey on Realistic Simulation of Cloud

QIU Hang,YANG Ke,CHEN Yu,CHEN Lei-ting

Computer Science. 2011, 38 (6): 14-19.

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Cloud is one of the nature elements that is difficult to render in real-time due to its peculiar microstructures and complex physical process of formation. Realistic simulation of cloud is one of the challenging topics in computer graphics. A comprehensive survey on realistic simulation of cloud in recent twenty years was presented, with a detail introduction to the modeling,dynamic simulation and light scattering effect technictues of cloud. Some fundamental principles, advantages and disadvantages of the typical methods were introduced and analyzed. Finally, some typical simulation methods were compared and summarized in detail, some key research issues that need to be further researched were pointed out.

Secure Network Coding: Challenges and Solution

LIU Wai-xi,YU Shun-zheng,CAI Jun

Computer Science. 2011, 38 (6): 20-27.

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In recent years,network coding has emerged some exciting future because of its smart technology. However,in order to let network coding become popular in the Internet, its security problem must be solved. Firstly, a wide range of attacks were revealed based on our systematic analysis of the components of these frameworks vulnerabilities. Secondly, this paper gave one proposal for ACK attacks and coding attacks based on Typical Set, Hash Functions and Markov model. Thirdly, one thinking named as Computing Network, which integrates Cloud Computing with Network Coding, was proposed. Finally, the open issues and challenges for network coding referring to both theory and applicalion in near future were proposed.

SC}GADL:A Grid Workflow Description Language for Scientific Computing

HUANG Zhen-chun

Computer Science. 2011, 38 (6): 28-30.

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The difficulty of grid-enabled application development is one of the obstacles to employ grid as infrastructure of scientific computing. Although there are many projects, especially grid workflow projects, trying to make grid-enabled application development easier and quicker, the process-based application description model adopted by most of the gridenabled applications still bothers scientists who are usually beginner in programming. In this paper, a data dependency based application description model was proposed, which describes a grid-enabled application via dependency among data items in the application, and much close to the thinking pattern of scientists. Based on this model, a scientific computing oriented grid application description language (SCO-GADL)was proposed, and an engine for supporting its execution was designed and implemented. The extensible plug-in architecture adopted by SCO-GADL and its engine makes them support different grid and non-grid platforms easily. At last, a test shows that grid-enabled scientific applications can be developed easily in SCO-GADI，and executed correctly on the application engine.

Distributed Deployment and QoS Performance Analysis of Grid Services Scheduling Algorithm

LIU Hong-lan,HAO Wei-dong,GAO Qing-shi

Computer Science. 2011, 38 (6): 31-34.

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Grid is a complex distributed computing system, distributed deployment and QoS performance analysis of grid services scheduling algorithm were studied. State space model was given to describe the grid dynamic scheduling system which processes a number of heterogeneous jobs concurrently. Clearing policy as a scheduling poficy and services sched uling algorithm were given. Distributed deployment problem was analyzed. System QoS performance parameters were calculated, stable throughput and stable response time and their relationship with load factor were pointed.

Analysis for the Inter-domain Routing System Based on Cellular Automaton Model

XU Zan-xin,YUAN Jian,WANG Yue,FENG Zhen-ming

Computer Science. 2011, 38 (6): 35-37.

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Analysis of the macroscopic routing behavior of the inter-domain routing system remains a difficult challenge because the inter-domain routing is a very complex system with very large scale. We proposed an inter-domain routing simulation model based on cellular automaton model to study the collective routing behavior of the inter-domain routing system. Our work reveals that the model can succeed in exploring the macroscopic routing behavior of the inter-domain routing system. Simulation results show that some undesired macroscopic routing behavior tend to arise when a smallpart of the generally well behaved nodes' unstable routing behavior is widespread over the whole network.

Network-aware Based Fault Tolerant Volunteer Computing

FAN Pei,SHEN Rui

Computer Science. 2011, 38 (6): 38-40.

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The traditional Master-slave model of volunteer computing is limitation due to the compositional nature of volunteer computing. Considering the volunteer nodes are usually from different locations, a Network-aware based model for fault tolerant volunteer computing was proposed. This model considers the network of the volunteer nodes and partilions the nodes into different subsets, based on this model volunteer computing system can tolerant some fault caused by network delay or timeout. In addition, the overlapping strategy was improved and it was applied to the fault tolerant volunteer computing. I}he results of experiments show that the network-aware model and improved overlapping strategy can improve the reliability and performance of the volunteer computing.

Study on AMS-02 Massive Data Processing Environment

YANG Peng

Computer Science. 2011, 38 (6): 41-44.

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AMS (Alpha Magnetic Spectrometer) is an international coorperative physics experiment with great influence and significance, and the AMS-02 tracker will be launched at the beginning of 2011. AMS-02 experiment will produce more than 1PB of massive data that have different types and their handling processes arc very complex This paper firstly introduced the functional requirements and the key components of the massive data processing environment of AMS-02 experiment,and then analyzed the fundamental data types and the handling processes of AMS-02 massive data,finally,paid more attention to AMS-02 SOC, the distributed architecture and the principal function of AMS-02 SOC were discussed, and a Grid-based implementation framework of AMS-02 SOC@SEU was also dicsribed.

PSD Congestion Control Algorithm in Ad-hoc Network

CHEN Liang,ZHANG Hong

Computer Science. 2011, 38 (6): 45-48.

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Neuron PID algorithm can control queue length successfully, but its neuron gain is sensitive for controlled object state. So it is difficult to guarantee the control performance because the gain depends on experience and trial method. Congestion window size, loss probability and queue length differential equations were deduced based on TCP window additive-increase and multiplicative-decrease (AIMD)principle and queuing mechanism. TCP/AQM control model was obtained in Ad-hoc network through the equations lincarization. Then it introduced recursion and modification gain to neuron PID based on the model. Finally, a neuron adaptive proportional summation differential (PSD) AQM was proposed. PSdalgorithm can modify neuron gain dynamically. NS simulations demonstrate that PSD ctueue management performance is better than neuron PID under conditions of wireless packet loss,sudden flow and different link capacity.

Remote Attestation Extension for IPSec

WANG Jian,WANG Hai-hang,YANG Jian

Computer Science. 2011, 38 (6): 49-53.

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Standard IPSec doesn't provide any guarantees about the integrity of the endpoints when an IPSec linkage is established. And the remote attestation in trusted computing is to provide security evidence of the user for the accessed server. So it can avoid terminal security vulnerability in IPSec to introduce the remote attestation into IPSec. IKE negotianon of IPSec and remote attestation mechanism were analyzed firstly. Then taking IKE main mode based on figure signature for example, an extended IPSec protocol based on remote attestation and its security analysis were presented. In the extended IPSec protocol,remote attestation mechanism was introduced into IKE negotiation. hhis protocol can complete double authentications including identity and system integrity by using a certificate with a SKAE extension to ensure an end-to-end secure linkage. Besides, the protocol can guarantee not only information' s confidentiality, integrity and freshness,but also endpoints' privacy.

New ID-based Aggregate Signature Scheme

WEN Yi-ling,MA Jian-feng,WANG Chao

Computer Science. 2011, 38 (6): 54-57.

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An aggregate signature scheme was proposed by I3oneh et al. in which multiple signatures can be compressed into a short signature. So it is more efficiency than others. We presented a new ID-based aggregate signature scheme.Compared with the scheme proposed by Xu et al. , our scheme requires less one pairing operation in the signing and verification, respectively. So it is more efficiency than the former. The proposed scheme is secure against existential forgery in the random oracle model by assuming the intractability of the computational DifficHellman (CDH) problem. Otherwise, we analysed the scheme proposed by Chen et al, and fould the scheme cannot against existential forgery.

Adaptive Data Dissemination Algorithm for Vehicular Opportunistic Networks

CAI Qing-song,NIU Jian-wei,LIU Chang

Computer Science. 2011, 38 (6): 58-63.

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Vehicular Ad-hoc networks (VANETs) are promising information-sharing technologies for modern intelligent transportation systems (ITS)，in which information can be disseminated and shared among a group of moving vehicles through wireless communication devices. Previous data dissemination schemes for VANETs arc unable to meet the rectuirements of effective and efficient data dissemination in VANETs due to the dynamic nature of the framework such as the intermittent connection between vehicles. An Adaptive Copy and Spread (ACS) data dissemination algorithm was proposed for opportunistic VANETs to adaptively adjust the dissemination strategics. Through making use of the moving parameters of vehicles (e. g. dircction,vclocity)，ACS can dynamically calculate the number of message copies to be broadcasted so that vehicles can intelligently start or stop a message spread stage. In addition, ACS was designed to keep the message located at the effective area's boundary, inform the entering vehicles as soon as possible. Our simulation resups show that ACS outperforms traditional Random Choice (RC) algorithm and Epidemic spreading (ED) algorithm with less network resource consumption in broad scenarios.

EDCA Model of TCP/UDP Flows Based on Non-saturation

ZHANG Nan,XIAO Yang

Computer Science. 2011, 38 (6): 64-69.

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IEEE 802. 11e EDCA mechanism permits using CFB (Contention Free Burst) , which will control the media in a whole TXOP. So it can save some time to occupy the channel and improve the QoS. But few papers think over TXOP in non-saturation. This paper proposed an easy analysis model of TC;P/UDP heterogeneous flows appear in non-saturated condition based on IEEE 802. lle EDCA mechanism the model thinks over CFB, the simulation results indicate that the model is valid on forecasting the EI}CA mechanism of mixed flows, and the interaction of the mixed TCP/UDP flows appear when they share the same channel.

Analysis and Elimination of the Dependent Relationships in Trust Networks

JIANG Li-ming,ZHANG Kun,XU Jian,ZHANG Hong

Computer Science. 2011, 38 (6): 70-73.

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Current trust aggregation methods have the problems of information loss or repetitive calculation that limit analysis and disposal of the dependent relationships in transitivity trust networks, which leads to the deviation between the computation trust value and the direct recommendation increasing. This article introduced a definition of trust subgraph, combined with its left neighboring nodes and right neighboring nodes, proved the existence of a relationship between the dependent relationships and the in-degree and out degree of nodes in trust graph, we proposed an algorithm to eliminate the dependency existed in trust graph. We also provided a numerical example to illustrate the validity and feasibility of our method.

Channel Estimation Based on Block-thresholding Wavelet Denoising for System

YANG Yong-li,LIU Jian,ZHU Guang-xi

Computer Science. 2011, 38 (6): 74-76.

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A block-thresholding wavelet denoising based channel estimation algorithm was proposed. The algorithm improved the channel estimation performance by denoising the channel frequency function estimated by Least Square Estimator using block thrcsholding wavclet denoising. Compared with the conventional algorithms, block thresholding wavelet denoising algorithm ultilized the local correlation of the wavelet coefficients, so using the proposed method the mean square error and symbol error rate can be reduced greatly, and the computation complexity is only linearly proportional to the number effective subcarricrs. hhe proposed method also poses good robustness when the CP length of the system is shorter than the delay spread of the channel. Numeric simulations show the performance improvement of the proposed algorithm to the conventional ones.

Analysis and Improvement of a Multi-signature Scheme Based on Trusted Computing

ZHANG Ya,ZHOU Yao

Computer Science. 2011, 38 (6): 77-80.

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Aimed at an anonymous multi-signature scheme based on DAA technology for trusted computing, this paper analyzed its security and demonstrates that it is vulnerable against signature forgery attack. The reasons why such security flaws exist in the scheme was investigated and an improved version was proposed. The improved scheme associates every signer's DAA certificate with its partial signature. The unforgcability of the final multi-signature is guaranteed because the attackers can not forge a l)八A certificate. The new scheme not only retains the major advantages but also overcomes the security flaws of the original scheme.

Research on Network Protocol Enhancing Mechanisms Based on Online Social Networks

ZHENG Qian-bing,ZHU Pei-dong,WANG Yong-wen,XU Ming

Computer Science. 2011, 38 (6): 81-83.

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Online social networks have developed rapidly. The social relationships and topology characteristics of online social networks can be used to enhance the function,performance and security of network protocols,so it becomes a hot research topic. The network protocol enhancing mechanisms based on online social networks were explored. Firstly the existing enhancing mechanisms based on their features were classified. Then the critical techniques used in these approaches were studied and the weaknesses of related research were summarized. Finally a network protocol enhancing model based on social-aware plane was proposed.

TDMA/CDMA Hybrid MAC Protocol for Wireless Sensor Network

GU Zhi-chun,XIAO De-qin

Computer Science. 2011, 38 (6): 84-87.

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An efficient MAC protocol is one of the keys for long-time working and high-performance communication of WSN. There are several mechanisms for wireless channel allocation, such as Contention-base Random Access, TDMA (Time Division Multiple Acccss),FDMA(Frcqucncy Division Multiple Access) and CDMA(Codc Division Multiple Access). According to WSN, the CSMA-based MAC protocol has disadvantages like idle listening and collision; the TD-MA-based and FDMA-based MAC protocol has low scalability problem; the CDMA-based MAC protocol has the problem of additional power consumption. After analyzing energy model of the pure TDMA, pure CDMA and hybrid TD-MA/CDMA，the paper presented a hybrid TDMA/CD MA MAC protocol based on cluster, which can solve the low latency and the conflict with interference. The protocol proposes the cluster nodes use TDMA and the cluster heads use CDMA. MAC could achieve collision avoidance and low latency in clusters, and do not have to ensure high accuracy synchronization between each cluster, so that the scalability of the sensor network would be enhanced.

Evaluation Method for Node Importance Based on Mutual Information in Complex Networks

ZHANG Yi,LIU Yu-hua,XU Kai-hua,LUO Zhen-rong

Computer Science. 2011, 38 (6): 88-89.

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In complex networks, how to quantify the importance of the node is a basic problem. First elaborated some of the existing computational method, then proposed an evaluation method for node importance based on mutual informalion. This method precisely reveals topology characteristic of the network, reflecting the relative importance of nodes. The experiment on the comparison and the analysis with other methods shows that the evaluation method based on mutual information is simple and effective, it is suitable for evaluating the node importance in large-scale complex networks.

Operation-based Multi-secret Visual Cryptography Scheme with Disguised Patterns

FU Zheng-xin,YU Bin,FANG Li-guo

Computer Science. 2011, 38 (6): 90-92.

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The ring shares were divided into the disguised area and the tagged secret areas. Combining with the basic matrices of (2,2) single secret visual cryptography, an operation-based multi secret visual cryptography scheme with disguised images was designed. The proposed scheme not only makes the number of secret images boundless, but also improves the pixel expansion and the relative difference of previous schemes. Furthermore, the meaningful disguised patterns can reduce the attackers' threats to shares.

Novel Non-stationary Time Series Anomaly Detection Model Based on Superstatistics Theory

YANG Yue,HU Han-ping,XIONG Wei,DING Fan

Computer Science. 2011, 38 (6): 93-95.

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Because of network traffic non-stationary property it can hardly use traditional way to analyze the complicated network traffic. A new detection method of non-stationary network traffic based on superstatistics theory was discussed. According to the superstatistics theory, the complex dynamic system may have a large fluctuation of intensive quantities on large time scales which causes the system to behave as non-stationary which is also the characteristic of network traffic. This new idea provides us with a novel method to partition the non-stationary traffic time series into small stationary segments. We used the slow parameters of the segments as a key determinant factor of the system to describe the network characteristic and analyze the slow parameters with time series theory to detect network anomaly.The result of experiments indicates that this method can be effective.

Integrated Route Strategy for Large Scale MANET

MA Chi,ZHANG Hong, LIU Feng-yu

Computer Science. 2011, 38 (6): 96-100.

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As the performance of large scale MANET with common Route method falls obviously, a novel ADHR route strategy which integrates AODV and Spay & Waiter protocols was proposed. In the range of AODV search extending ring,it still executes common AODV route protocol. But out of the range,the source node and the destination are too far away from each other, the Spay & Waiter protocol begins to work. By this way, the performance of large scale MANET becomes stable. The ONE experiment result shows that the main performance of ADHR (such as delivery rate) is better than AODV and Spay & Waiter route protocols.

Worm Warning and Optimization of Nonlinear Propagation Model

TONG Xiao-jun,WANG Zhu

Computer Science. 2011, 38 (6): 101-105.

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At present there arc some worm intrusion detection systems which detect network worms only by using worm propagation properties and have high false alarm rate. This paper analyzed worm non-linear propagation models, realized the optimization of worm model, and proposed distributed worm propagation model. Then a distributed worm detection technology was designed according to the distributed worm propagation model. The system uses rule-based detection method to monitor network worms, and the console side manages and coordinates detection work of the client sides. The experimental results show that the technology is a good solution to worm warning and worm detection, which can give an alarm with high detection rate and low false alarm rate.

Tasks Assignment Algorithm Based on Entropy for Wireless Sensor and Actor Networks

YI Jun, XU Lei

Computer Science. 2011, 38 (6): 106-109.

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Aimed at "hot zone" problem of wireless sensor and actor networks, a tasks assignment algorithm based on entropy was proposed to make the whole network energy consumption more balanced. Considering network situation,the entropy-based cost of taking action model was established by using auction method. The task assignment problem among actors was formulated as a balanced or non-balanced task assignment optimization problem, different task units were executed in parallel to enhance higher real-time response. The result of simulation shows that the algorithm can provide more balance in energy consumption and higher real-time performance.

Context-aware Optimized Link State Routing Protocol for Fast Movement Scene

ZHANG Ke,ZHANG Wei,LI Wei,ZENG Jia-zhi

Computer Science. 2011, 38 (6): 110-113.

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An Context aware optimized link state routing protocol for networks with fast moving nodes was proposed CAOLSR (Context-aware Optimized Link State Routing Protocol) adopts a context aware mechanism,and selects MPR (Multi Point Relays) based on relative movement of nodes, recent access-time and connection number of nodes, and adopts a special flow of MPR selection. In addition, by the introduction of Fisheye, reduces the influence from mobility on the routing accuracy. Experimental results show that CAOLSR can achieve good performance and outperform HOLSR (Hierarchical Optimized Link State Routing Protocol)，OLSR (Optimized Link State Routing Protocol) and DSDV (Destination Sequenced Distance Vector) in networks with fast moving nodes.

Intra Macro Block Refresh Approach for Wireless Video Transmission

QIU Jin-bo,FENG Bin,DENG Hui-ping,YU Li,ZHU Guang-xi

Computer Science. 2011, 38 (6): 114-117.

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Infra macro block refreshing is an important error resilient approach for video transmission. The error resilient of wireless video transmission was analyzed and several infra macro block refresh methods were compared. After that, an improved macro block refresh approach was proposed. Based on the analysis of the mainly motion direction of the video, the approach chose different infra macro block refresh strategy to decrease the proportion of infra macro block in the frame and maintained the similar error resilient ability. hhe proposed approach was compared with number of intra macro block refresh methods for the same video frame loss pattern. The experimental results show that the new approach can refresh the decayed video quickly, at the same time increase the coding efficiency. The proposed approach has a good subject and object quality and compatible with all the current video coding standards.

Complex Network Model and Application in Epidemic Spreading and Controlling

CHEN Duan-bing, HUANG Sheng,SHANG Ming-sheng

Computer Science. 2011, 38 (6): 118-121.

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Study of complex networks becomes a hot research topic. Complex networks arc applied to many applications such as engineering technology, society, politics, economics, medicine and management. Many scientists paid much attenlion on structures and dynamics of complex networks. Epidemic spreading in complex networks is one of the most important aspects. hwo classical complex network models, small world network model and 13A scalcfrec network modelwere studied in this paper. SIR spreading model was used to simulate the epidemic spreading and the spreading threshold, and to study two immunization strategics, stochastic and target, how to influence the spreading threshold. Spreading and controlling of H1Nl were simulated in the non-immunization case as well as in the stochastic and target immunizalion cases. Simulation results demonstrate that target immunization can restrain the spreading of epidemic effectively.

DWATrust:Doubly Weighted Average Based Dynamic Comprehensive Trust Model for P2P Network

RAO Shen, WANG Yong

Computer Science. 2011, 38 (6): 122-126.

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According to the existing P2P network's deficiency of inadequately considering the difference and the dynamic in peers' behavior when aggregating peer trust valucs,a new dynamic comprehensive trust model (DWAI}rust) was proposed. In this model, a Multi-dimensional Time Series are firstly applied to record evaluations on peers in some past time segments responding to different indexes. Secondly, the different weight for each evaluation index in each time segment is computed by "Entropy Method" and then the first comprehensive weighted evaluation result in different time segment can he obtained. Finally, the time weight for different time segment can be computed by resolving a nonlinear programming problem and then the second comprehensive weighted evaluation is carried out to obtain the final trust value. Hence, this model not only takes into the consideration that the dynamic changes in transaction context and peer context will influent the peer trust value, but also employs time granularity to reflect the changes. Simulation experiment shows that the model can well identify the malicious peer behavior such as taking strategy to proceed periodic oscillation cheating and then improve the improve transaction success rate.

Research of an Efficient Variant of Batch RSA Algorithm

LI Yun-fei,LIU Qing,LI Tong,HAO Lin

Computer Science. 2011, 38 (6): 127-132.

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This paper aimed at speeding up Batch RSA decryption. An efficient variant of Batch RSA was proposed to improve the Batch RSA decryption performance. The improved Batch RSA variant speeds up decryption by combining the load transferring technique and multi-power RSA technique in the exponentiation phase. I}he experimental result and the theoretical values show that the speed of the decryption is substantially improved and the variant can be efficiently implemented in parallel and parallel implementation of the variant on multi-core devices can further improve the overall performance of Batch RSA algorithm.

Efficient ID-based Proxy Signature in the Standard Model

YU Yi-ke,ZHEN Xue-feng,HAN Xiao-guang,LIU Xing-bing

Computer Science. 2011, 38 (6): 133-139.

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At present, the security of the identity based proxy signature schemes was almost proven in the random oracle model, but for which any implementation of the random oracle results in insecure schemes. It is more practical to design threshold proxy signature scheme in the standard model, compared with the existing ones. This paper presented an secure and efficient ID-based proxy signature scheme (IBPS) in the standard model. The scheme's correctness was exactly proven in terms of bilinear pairing technique and its security analysis and prove was given in detail in the assumption of the computational DifficHellman problem. Compared with the known identity based scheme in the standard model, the scheme enjoys less operation.

Improved IPv4/v6 Network IDS Technology

Computer Science. 2011, 38 (6): 140-141.

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IPv6 has many advantages over IPv4, such as almost infinite address space, auto-configuration mechanism, a simplified header structure, built-in IPSec protocol, extension headers, and the convectivc label support and so on. Nowadays, Applications based on network become more and more popular, and people pay more attention to the security of network communication as before. Network products such as IDS have already played a very important role in network.As the IPv6 time is coming, this paper proposed an improved model of IPv6 Intrusion Detection System. , which using a combination of dual stack, IPv4 protocol analysis, and network auditing techniques. We expect this system can be applied in IPv6 environment as well as IPv4 to IPv6 transition environment to play a more efficient role to detect network intrulions.

Novel Digital Watermark Scheme Based on Wavelet Transform and Neural Network

CHEN Jun,ZHANG Wei, YANG Hua-qiang,HE Chun-xiao

Computer Science. 2011, 38 (6): 142-144.

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A novel digital watermark algorithm based on wavelet transform and neural network was proposed. Firstly,the original image was divided into some small blocks (8 X 8 pixels). The sub-image consists of some small blocks that are selected throuth logistic map. Two sub-bands LHl and HLl were generated by acting DWT on the sub-image. Secondly,the watermark was embedded into the sub-band's wavelet coefficients. The watermarked sub-image was reconstructed using CWT. Finally, we put every small block (8 X 8 pixels) of the watermarked sub-image into the initial position of the original image. Thus,we got the watermarked image. Experiments show that the watermark embedded by this scheme has good robustness,imperceptibility and security.

Security Analysis Approaches for Group Key Agreement Protocols

ZHAO Xiu-feng,XU Qiu-liang,WEI Da-Wei

Computer Science. 2011, 38 (6): 145-148.

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Group Key agreement allows multi users to establish a common session key though insecure channels. Designing secure group key agreement protocols is one of the most fundamental cryptographic tasks. This paper introduced two approaches developed for analyzing security group key agreement protocols: computational complexity approach and formal analysis approach. The key technologies of computational complexity approach were discussed, including the proof technology based on reduction and simulatability, and security models based on reduction and simulatability. The trends in this field were presented.

Image Encryption Scheme Based on Novel Hyperchaotic System

LU Hui-bin,SUN Yan

Computer Science. 2011, 38 (6): 149-152.

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Proposed a new hyperchaotic system, analyzed the new system, the phase diagram of the chaptic attractor, and the nature of the ectuilibrium point, Lyapunov exponent, nonlinear dynamics properties and so on, proposed a novel image encryption scheme based on a four dimensional hyperchaotic system .The experimental results and security analysis show that the new scheme has stronger resistance for the exhaustion attack, count attack and known-plaintext attack,and it is of high security.

Cross-layer Data Transmission Control Based on Active Noti行of Vehicular Ad-hoc Network Node

LI Yuan-yuan,SONG Jun,JIN Yan-hua, HUANG Da-rong

Computer Science. 2011, 38 (6): 153-156.

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To enhance the QoS of data service in vehicular Ad-hoc network, we improved the data transmission control mechanism on technology of Wireless Access in Vehicular Environment(WAVE) and proposed a cross-layer data transmission control scheme based on Active Notify of vehicular Ad-hoc network node(Active Notify EDCA, AN-EDCA).Simulation results indicate, AN-EDCA cross layer data transmission control mechanism efficiently enhances the throughput and guarantees the QoS of data service in vehicular Ad-hoc network.

Security Information Flow Model Based on Grid Environment

LIU Yi-he

Computer Science. 2011, 38 (6): 157-160.

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The grid security is an important component, and it directly affects the development of the grid and the practical application of grid system software. In order to fully describe the information flow based on grid environment, a new security information flow model based on grid environment was given, in which the safety class was divided and the information flow policy was defined by using the organisation security classifications, classifications, and integrity grade of the object. In this article,the subject and the object were extended,and the concepts of the decomposition of the subject and object,and of organisation security classification were defined. hhe strict mathematics verification shows that this new information flow model satisfies the character of finite lattice and least upper bound operator of the Denning's information flow model,it is reasonable and safe. It is an extension of information flow model contrast to BLP model's and Biba model's, but also the expansion of security information flow model based on the general network environment, and there has some positive significance for the study grid security.

Internet Based JAR Usage Information Collection Method

ZOU Yan-zhen,LIU Chang-sheng,LI Meng,XIE Bing

Computer Science. 2011, 38 (6): 161-164.

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With the development of software reuse technologies,more and more reusable software assets emerge on the Internet,such as Web Scrvices,JAR packages and so on. However,necessary description and using help information are often missed in these software assets. Therefore,we proposed an Internet based JAR package usage information collection method, which finds, reorganizes further, the description and the user commented corresponding to a JAR package.Based on this work,we implemented the usage information collection tool for JAR package in PKU Software Asset Repository. It has collected and organized description and user comment information for more than 6000 JAR packages.

Research and Implementation of Deployment and Configuration Tool for Light-weight Components

SHI Dian-xi， DING Bo， CUI Wei，ZHANG Yi-ming，WANG Huai-min

Computer Science. 2011, 38 (6): 165-168.

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Pervasive computing applications run in highly heterogeneous and dynamic changing environments. Therefore,it is a great challenge for pervasive computing to deploy and configure this kind of pplications conveniently and efficicntly. In order to support the deployment and configuration (D&C) of component based pervasive computing appli-canons, this paper proposed the design and implementations of a (D&C).C tool for light weight components, StarDCTool,which is based on the model-driven paradigm and complied with OMG’s light-weight component (D&C)specification.StarDCTool deals with the terogeneity by modeling the target platforms and enables the reuse of the (D&C) process of component based applications by modeling the deployment plan. Based on those modeling results, StarIX;Tool can ge-nerate the meta-data related to the (D&C) process automatically. We validated the functions and features of StarDCTool by a component based navigational application.

Research of Evaluating Model on the Criticality of Software Vulnerability

LI Yi，LI Xin-ming，CUI Yun-fei

Computer Science. 2011, 38 (6): 169-172.

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The criticality of software vulnerability is the measurement of the potential risk of which the software vulner-ability may be taken advantage for attacking the system. Based on analysis of current evaluation methods and their limitation, an analysis framework for evaluating the citicality of software vulnerability was proposed, according to the impact severity and probability of vulnerability. Based on fuzzy theory, the quantification model for evaluating the criticality of software vulnerability was proposed and the hierarchy of fuzzy evaluation factors’relationship and membership was established. The fuzzy set based indices quantification, the fuzzy relational matrix-based indices weight value and the general evaluation method for software vulnerability criticality were emphasized. At last, the application and implement of the evaluating model were given.

Trustworthy Web Service Composition Approach Based on QoS

XIAO Wen，ZHANG Zi-li，LI Wei-hua

Computer Science. 2011, 38 (6): 173-176.

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How to select and combine the services from available ones with similar functions appropriately and efficient1y to provide much better services for users is an important yet difficult issue in SOA. The rationality of service composition is improved to a certain extent with the introduction of Quality of Service(QoS). However, there is still no effident way to ensure the trustworthiness of the service composition. With such an observation in mind, a Trust Web Service Composition Modcl(hWSCM) was proposed to enhance the trustworthiness of service composition. hhis was achieved by adding QoS agents and trust control module to existing typical Web service composition models. Finally, experiments were conducted on the Language Grid (http://langrid. nict.go. jp). The experimental results show that the proposed approach can provide trustworthy composite services with high quality.

Automatic Service Orchestration by Dynamically Binding

LIANG Ping，YANG Xian-ze

Computer Science. 2011, 38 (6): 177-179.

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In a service-oriented system,business processes are completed by services. The compositionahty of services to cope with changing business world is required to be flexible and robust To complete dynamic service composition is hardly an easy one. hhough there arc many ways that aim to optimize and improve attributes of a SOA system, automalion is little realized due to the complicated business process and tedious service composition tools. This paper introduced a way to express business process in FOIL formula and dynamically bind atomic services by computing FOIL for mina and generating a BPEI structure for execution of service composition. harski's hruth theory proves this process is plausible in application.

Service-oriented Domain Feature Model

WU Ying-bo，WANG Xu

Computer Science. 2011, 38 (6): 180-182.

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To solve the problems of service-oriented domain rectuirements expression and specification organization, a extended concept of service feature and its model of were proposed,and a ontology-meta model of service feature based on OWL(Ontology Web Language) was also presented. The extended concept of service feature can more fully describe the semantic information of service requirements, and the proposed model provides a flexible and extensible organization structure for service-oriented domain requirements. I3y defining the mapping relationship of service features in the model, the model overcomes the disadvantages of traditional feature model, richens the semantic relationship of service features, and provides a more realization mechanism for configuration management and refinement of domain requirements based on feature. Lastly, a computer-aided modeling prototype tool was introduced. I3y developing the prototype tool, the proposed model is proved to be adaptable for scrviccoriented domain analysis & modeling.

Research on Frequent Itemsets Mining Algorithm Based on High-dimensional Sparse Dataset

YAN Zhen， PI De-chang，WU Wen-hao

Computer Science. 2011, 38 (6): 183-186.

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The traditional mining algorithms arc not applicable to mine high-dimensional sparse dataset,a new frequent itemsets mining algorithm based on high-dimensional sparse dataset named FIRS (Frequent mining algorithm based on High-dimensional Sparse dataset) was proposed in this paper. FIHS adopts a new data structure to store frequcnt itemsets, using this structure can reduce the storage space and the cost of counting. FIHS can avoid generating infrectuent candidate itemsets through optimizing the operation of connection and pruning,which rectuires scan the dataset once. What's more,just by applying ANIX)R operation,frequcnt K+1-itemsets can be created according to frequent K-itemsets, and the maintenance of the data structure is simple. According to theoretical analysis and experiments, the improved algorithm enjoys many advantages aiming at high-dimensional sparse dataset, such as quick mining, less memory spacc,etc.

Scalable Distributed Inverted Index Built on Cassandra

TANG Li-yang ，NI Zhi-wei，LI Ying

Computer Science. 2011, 38 (6): 187-190.

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As the age of cloud computing,giant Web-scale application and massive data exert big challenges on centralined data retrieval. It becomes a tricky issue to process efficiently data retrieval in distributed environment. Traditional relational database is not fully suitable to the cloud any more. As a novel cloud storage, NoSQL (Not only SQL) emerges, among which Cassandra is widely used. With the application of index building under the distributed multi-node architecture, a scalable distributed inverted index built on Cassandra was put forward to solve the problem. Besides, analysis on data model and processing flow, as well as a performance test about Cassandra, were proposed.

Single-class Classification Approach Based on Integrated Pyramid Model

XUE Wen，XIE Yong-hong，Ma Yan-hui，YANG Ring-ru

Computer Science. 2011, 38 (6): 191-194.

Abstract

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A Integrated Pyramid Model is proposed for Single-Class Classification(Single-Class Classification Integrated Pyramid Mode1,SCCIPM). This model is composed of four independent collaborative layers by Comprehensive obtain layer, Assistant j udgment layer, Kernel classification layer and Optimization layer. Comprehensive obtain layer formed by improved KNN and optimized 1-DNF two classification methods,mainly for obtaining negative examples,results are submitted to Assistant judgment layer voting reliable negative examples. Kernel classification layer update reliable negalive examples by several iteration, each iteration establish a classifier. Optimization layer according to Kernel Classificalion layer of different classifiers, optimally select the final classifier. The simulation experiment result indicates that when positive examples arc 50 0 0 of total samples below, SCCIPM shows obvious advantages over other methods in solving the SinglcClass Classification and has good classification performance.

Research on Analysis and Management of Dynamic Target Spatio-temporal Data

GAO Ren，TANG Long，WU Jue-bo

Computer Science. 2011, 38 (6): 195-199.

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Dynamic target has a lot of characteristics such as spatiality, timeliness, multidimensionality, magnanimity, complexity and uncertainty, but the traditional DBMS can't provide an effective way for its position modeling, semantic expression and index In order to solve this problem, this paper presented a general framework to model, analyzed and managed the dynamic target spatio-temporal data by analyzing the dynamic target. This framework uses three-layer structure, insuring the system with high flexibility and expansibility. Finally, a prototype system based on the framework was given, and the main componented of platform were analyzad and expounded.

Fuzzy Extension of OWL Supporting Representation of Customized Fuzzy Data Type

GHAO Fa-xin， MA Gong-mini，WANG Hai-long

Computer Science. 2011, 38 (6): 200-204.

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The Semantic Web is expected to process fuzzy concept knowledge and data type information in an intelligent and automatic way. Recent research has shown that OWL has some serious limitations; i. e.，it can't process imprecise and uncertain information which widely exists in the Semantic Web and ontology; furthermore, it does not support customized data types and customized data type predicates. In this paper, we made the following two contributions to solve the above limitations; (i) presented a new kind of fuzzy description logic F-SHOIN(G),and gave its syntax and seman-tics; (ii) extended OWL to f-OWL by recoding the description norms of OWL，based on F-SHOIN(G) and the syntax specification of RDF/XML. f-OWL can not only support the representation of fuzzy concept knowledge, but also fuzzy data information with customized fuzzy data types and customized fuzzy data type predicates. It provides a new representation method for the investigation of ontology.

Research on Deep Web Classification Approach Based on Quantum Self-organization Feature Mapping Network

ZHANG Liang， LU Yu-liang， FANG Shan-yao

Computer Science. 2011, 38 (6): 205-210.

Abstract

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In order to solve the problem of Deep Web data sources classification, this paper firstly researched how fealures in different position could effect the domain of Deep Web interfaces, and proposed a feature selection method RankF W which is based on Ranked weights. Then, a quantum self-organization feature mapping network model was proposed with a classification algorithm This model relies on the feature vectors and target vectors incoordinately in different phases of training, making a more centralized distribution of winner neurons in competition layer and more obvious boundaries among clusters. Finally, some experiments were designed and carried out on the expanded TEL-8 dataset to test the validity of RankFW and DR-QSOFM.

Fuzzy/Temporal Characteristic of Vector Space on Fuzzy Temporal Database Design

DENG Li-guo，MA Zong-min

Computer Science. 2011, 38 (6): 211-216.

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The goal of database design is to generate a set of patterns, which not only reduces data storage redundancy,but also conveniently accesses to information. This is by design to meet the appropriate normal form model achieved.Functional dependency FD is an effective tool. The key is the mapping of fuzzy-valued and multi-granularity fuzzy temporal sequence to extend the traditional FD to fuzzy temporal functional dependency FTFD for multi-granularity fuzzy temporal database design. To effectively express fuzzy八emporal characteristic of vector space on fuzzy temporal database design by analyzing Limited closure of attribute set, the closed set of temporal types set, the concepts of attribute set in a gaven temporal depends on the state of such as the fuzzy八emporal characterization vector. And the correctness of this method was demonstrated. This method can be easily expressed on the computer, to determine mapping relations of fuzzy attribute values and fuzzy temporal sequence for the paradigm of fuzzy temporal database and to provide an effective means of decomposition.

Storage of Fuzzy Ontologies Based on Relational Databases

LU Yan-hui

Computer Science. 2011, 38 (6): 217-222.

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As fuzzy ontologies arc widely used in describing fuzzy information in the Semantic Web, how to efficiently store fuzzy ontologies is becoming a more important research issue in the domain of the Semantic Web. An approach to store fuzzy ontologies based on relational databases was proposed by making use of the advantage of organizing and managing data of relational databases. Firstly, a method of representing fuzzy datatypes was introduced by fuzzy extending of the RDF datatypes. Then, the storage schema of fuzzy ontologies using relational databases was presented. On this basis,the storage processes of the fuzzy ontologics structure and instances were given. Finally, the correctness of the stotage schema of fuzzy ontologies was proved. The approach of storing fuzzy ontologics in relational databases provides an efficient solution to the storage and management of fuzzy data in the Semantic Web.

Rationalism and Empiricism on the Combination in Machine Translation

XU Jin-an

Computer Science. 2011, 38 (6): 223-229.

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This paper firstly discussed the development of machine translation, secondly described the advantages and disadvantages of the rationalism and empiricism in natural language processing and machine translation, and thirdly introduced our basic ideas of combination of the rule-based approach and statistical approach. Furthermore, the paper deliberated the tendency of combination of the rationalism and empiricism in word sense disambiguation, finally summarizcd the developmental tendency of machine translation.

Quality Evaluation and Prediction for Question and Answer in Chinese Community Question Answering

LI Chcn，CHAO Wcn-han，CHEN Xiao-ming，LI Zhou-jun

Computer Science. 2011, 38 (6): 230-236.

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The rise of Knowledgcsharing platform on the Internet in China provides a new approach for Automatic Question Answering. However, the quality of User-Generated Content in such social networks may vary significantly,from useless information to malice spam. Identifying and filtering such content arc particularly important to improve users' experience and the performance of Question Answering System. We first extracted a set of question answer content from Chinese Community Question Answering site, investigated a series of statistic characteristics on the interaction of participants, and then manually annotated quality of a subset of these questions and answers. By combining text features and non-text features provided by the community extracted from those questions and answers,we established acontent quality classification model for evaluation and prediction. We find that this model is able to distinguish highquality ones from others with considerable accuracy.

Rough K-means Clustering Based on Self-adaptive Weights

ZHOU Yang，MIAO Duo-qian，YUE Xiao-dong

Computer Science. 2011, 38 (6): 237-241.

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The fixed weights are adopted in the traditional rough K-means algorithm to represent the different approximations of the clusters, but it is always difficult to predefine the optimal weights with little priori knowledge before clustering. Therefore,an improved rough K-means algorithm based on self-adaptive weights was proposed in this paper.The new method computes the weights for every data according to the current clustering state and no more does rely on the initial weights. Furthermore, the self-adaptive weights arc obtained from the Gaussian distance ration in cluster approximation, which can lead to the more accurate clustering results. The experiments indicate that the rough K-means based on self-adaptive weights is an effective rough clustering algorithm.

Research of Online Writeprint Identification Based on Ensemble Learning and Genetic Algorithm

SUN Jian-wen，YANU Zong-tra， LIU San-ya，WAND Pei

Computer Science. 2011, 38 (6): 242-245.

Abstract

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Online writeprint identification is a technique to identify individuals based on textual identity cues people leave behind online messages. Character N-gram is one of the most effective approaches to identify writeprint according to previous research. "ho deal with the high dimensional and redundant feature problems and the property of each feature being valuable for the task of writeprint identification, an ensemble learning approach based on feature subspacing was proposed in this study. The essence of this method is to partition the features into distinct subsets. Firstly, the whole feature set is split into equally sized and disjoint subsets. Then each of them is used to train a base classifier using Multinomial Naive Bayes. Finally, these individual classifiers arc aggregated to construct the ensemble via an appropriate combination rule which is a simple average of arithmetic mean and geometric mean. Additionally, genetic algorithm was used to optimize the feature subspacing (i. e. feature subsets selection). To examine the approach, experiment was conducted on a real world test bed. Performance results showed the proposed approach was quite effective and obtained a considerable improvement in accuracy compared with the benchmark technique in writeprint identification (Support Vector Machine).

Research on an Ensemble Method of Uncertainty Reasoning

HE Huai-qing,LI Jian-fu

Computer Science. 2011, 38 (6): 246-250.

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Ensemble learning is a machine learning paradigm where multiple models arc strategically generated and combined to obtain better predictive performance than a single learning method. It was proven that ensemble learning is feasible and tends to yield better results. Uncertainty reasoning is one of the important directions in artificial intelligence. Various uncertainty reasoning methods have been developed and all have their own advantages and disadvantages. Motivated by ensemble learning, an ensemble method of uncertainty reasoning was proposed The main idea of the new method is in accordance with the basic framework of ensemble learning, where multiple uncertainty reasoning methods is used in time and the result of various reasoning methods is integrated by some rules as the final result. Finally, theoretical analysis and experimental tests show that the ensemble uncertainty reasoning method is effective and feasible.

Affinity Class-hyperparallel Fuzzy Support Vector Machine

ZHANG Ya-pu,MENG Xiang-ru,ZHAO Wei-hu,ZHANG Li

Computer Science. 2011, 38 (6): 251-254.

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An Affinity Class-Hyperparallel Fuzzy Support Vector Machine was proposed to get better classification result. This method not only takes the advantage of the affinity, but also abandons the estimation that the samples obey spherical-shape distribution. Instead of the cluster center, a hyperplane within the class is used to find a hyperparallel with the minimum distance while containing the maximum samples by the way of quadratic programming. The membership is achieved through a new S-function based on the distance of the hyperparallcl which reflects the affinity of the samples. The simulation on UCI shows that the ACHFSVM is more robust and has better classification accuracy.

Harmony Search Algorithm for End-of-Life Items Disposal Facilities' Location Problem

HAN Yi,CAI Jian-hu,ZHOU Gen-gui,LI Yan-lai,SONG Ping

Computer Science. 2011, 38 (6): 255-258.

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In recent years, with the enforcement of people's environmental protection awareness and the improvement of environmental protection regulation,more and more focuses and importance are attached on reverse logistics. End-of-life items disposal facilities' location problem (EIDFI_P) is a key research direction in reverse logistics research. Whether the EIDFLP can be effectively solved is directly related to the degree of improvement on people's daily life. In this paper,for solving a multi-objective EIDFLP from literature,the multi-objective EIDFLP was transformed into a single-objective problem and then a novel harmony search algorithm (HSA) was proposed. hhrough the computational results,we found that the best result of HSA is the same as that in literature, the computational time is much less than that of algorithm in literature and there arc some errors in a reported solution.

Undirected Graph Languages

SHI Hai-zhong

Computer Science. 2011, 38 (6): 259-261.

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Undirected graph is a elementary concept of graph theory. Graph semigroup is a concept proposed in 1991. A concept of undirected graph language was proposed with undirected graph and graph semigroup. Furthermore, a subclass of undirected graph language, plane graph language was studied. It is proved that a graph language is a plane graph language if and only if it contains no subdivision graph language of K5 language or K3,3 language. In addition,four open problems were proposed. One of them:what is the relations between undirected graph language and regular language,context free language, context sensitive language, phrase structure language, respectively.

Research of Sketch Symbol Recognition Based on Bayesian Network

LI Lu.GHOU Liang.DING Qiu-lin

Computer Science. 2011, 38 (6): 262-265.

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To solve the current algorithm' s limitation of restricting the users' drawing style, this article introduced a method of dynamically constructing Bayes net to sketch symbol recognition system.This paper adopted a identifying algorithm which is a combination of bottom-top and top-bottom. From bottom to top it realizes the segmentation of strokes,generating hypothesis templates according to posterior probability then generating graphics templates. From top to bottom it realizes regrouping strokes through reconfiguring hypothesis templates and handling nosiy input according to the empty slot of templates. Through being applied to the domain of UML, we can get better recognition effect without restricting users' freely input.

Approach Based on Graphics Model for Semantic Modeling in Soccer Video

WANG Hao-ran,BAI Lian, LAO Song-yang

Computer Science. 2011, 38 (6): 266-269.

Abstract

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The Semantic Gap which exists between video low-level features and high-level semantics is the bottleneck of the video analysis and retrieval. To bridge the gap in football matches videos, the graphical model was brought in, and the Video Semantic Graph was proposed to modeling the high-level semantics. In addition, a DFS-based VSG matching algorithm was proposed, the time complexity and the space complexity were analyzed. The results of the experiment demonstrate the validity of the presented method，which can solve the problems of video semantic modeling and matching.

Research on Target Contour Feature Extraction Based on Image Potential Energy Theory

CHEN Xue-song XU Xue-jun ZHU Hong-bo

Computer Science. 2011, 38 (6): 270-274.

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A good feature extraction method helps to improve the efficiency of pattern recognition system and classificalion system. Computing of potential energy of an image can be used to extract and save image features, which is a new theory to collect and store the potential energy of each pixel in order. In this way, the feature of the image is better retamed contributing to storage and classification. Contour is the main distinction between different objects. With potential energy theory, the potential energy computed can better show the image feature with the high advantage of speed, easy computing and less storage space. hhe theory can be applied to target recognition and target classification and so on.

Hyperspectral Images Compression Algorithm Using Adaptive Band Regrouping

BAI Lin,HE Ming-yi,DAI Yu-chao

Computer Science. 2011, 38 (6): 275-278.

Abstract

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Aiming at handling the difficulty of storage and transmission caused by the large volume of data, a hyperspectral image compression algorithm was proposed, which combines adaptive band regrouping and bit rate prcallocation.The bands regrouping preprocessing based on affinity propagation clustering and reference frame selection were utilized to exploit spectrum correlation sufficiently. The interband prediction was applied to dccorrelate the spectrum redundancy in different groups while bit ratio prcallocation was utilized for intraband compression according to the information of prediction residual. Experimental results show that the proposed approach achieves a good performance in quality and complexity, the average peak signal to noise ratio (PSNR) is higherthan the state of the art algorithms.

Solution to Render the 2D Timely in the 3D Visual Reality

YANG Yang,XIAO Fei,MENG Kun,ZHAO Xiao-yong

Computer Science. 2011, 38 (6): 279-282.

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This paper gave a solution to render the 2D timely in the 3D visual reality, and testified the feasibility of this solution.To load the solutions in the 3D visual reality not only can realize users' interaction with the 3D environment,but also can integrate the excellent 2D applications in 3D visual reality which can cover the defects that current 3D visual reality has little support to the 2D applications.

Face Recognition Based on Wavelet Multiscale Singular-value Decomposition

ZHAI Jun-hai,WANG Hua-chao,ZHAI Meng-yao,WANG Xi-zhao

Computer Science. 2011, 38 (6): 283-285.

Abstract

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As a matrix decomposition method, singular value decomposition

Denoising Algorithm with Wave Atoms Based on Nonlocal TV Regularization

WU Yu-lian,FENG Xiang-chu

Computer Science. 2011, 38 (6): 286-287.

Abstract

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A novel denoising model for texture images was proposed,which combines the new multiscale geometric analysis tool-wave atoms and nonlocal total variation regularization scheme. This model well considers the advantages:wave atoms which has the ability of sparse representation of the oscillatory texture images and nonlocal TV version has the ability to handle better textures. Numerical experiments show that the proposed model significantly improves the SNR, performance of preserving details is much better than both only wave atoms threshold and nonlocal TV, therefore together with better visual effects.

Performance Evaluation for the Algorithms to Measure Texture Coarseness

ZHAO Hai-ying,XU Guang-mei,PENG Hong

Computer Science. 2011, 38 (6): 288-292.

Abstract

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Texture coarseness is the highest level of texture feature of visual perception. It is very important that lower features are transformed to higher semantic features. Many measure texture coarseness algorithms of image were proposed based on different application background. But they are lack of comparison and evaluation of the overall and are only limited to the selection of the GI_CM method. This paper made a testing among these methods in different images and noise images. The experimental results show that five kinds of texture coarseness measurement algorithm have different textural performance, rotation invariance and algorithm robustness. A reference model was given to select diffcrent algorithm of texture coarseness measurement algorithm based on different application.

Progressive Fine Granular Threshold Method Oriented to Fast Global Motion Estimation

ZHENG Jia-li,QI Tuan-fa

Computer Science. 2011, 38 (6): 293-297.

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The method of the fast global motion estimatin focuses on separating global motion region and local motion region. The key point of this method is how to set the appropriate threshold. This paper proposed a progressive fine granular threshold technique to solve this problem. I}he technique is divided into following two steps: firstly, distinguisking coarsely the global motion region and local motion region by using a luminance error threshold model integrating statistics method and average threshold method; secondly, during the iteration for minimizing error, refining the set of the global motion pixels by using a hierarchical threshold method based on motion vector error. By this means the whole global motion region can be obtained and the fast global motion estimation can be achieved.

Architecture Design of Embedded Real-time Operating System for Heterogeneous Multi-core Processor

JIANG Jian-chun,WANG Tong-qing

Computer Science. 2011, 38 (6): 298.

Abstract

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Because of the different structure between heterogeneous multi core processor and symmetric multi core processor, the traditional distributed operating system and multi-core operating system arc not suitable for heterogeneous multi core processor in real-time and efficiency performance. After researching characteristics and trend of developing of the heterogeneous multi-core processor, this paper presented a multi-master mode real-time operating system architec-lure, in which the multi-master mode in communication bus is introduced, and symmetric structure and modularization frame are used to design operating system architecture. In this operating system, every kernel may be master to manage resources, tasks and other shared devices to improve the real-time and efficiency performance, and to solve the bottleneck problem that the single master can not meet the requirement of performance with increasing of the slave number.This architecture can satisfy different structure processor core with configuring function module. On the other hand, it can also reduce the development difficult of the heterogeneous multi core processor operating system.