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• 2011, No. 7　Published:21 July 2011 Last issue    Next issue
  Columns in this issue: 论文

• 论文

  KSEFS:A ServerOriented Encrypted File System Supporting Cypertext Sharing

  HE Lianyue,LIAO Xiangke,FU Songling,TANG Xiaodong,DENG Kefeng

  2011, 33(7): 1-5. doi:

  Abstract ( 504 )   PDF (483KB) ( 450 )   　　

  To solve the security problem in electronic data storage and exchange, this paper presents the technology of Encrypting Share Box (ESB). ESB is the basic encryption entity on the server, which can not only provide transparent data encryption storage, but also support a flexible encrypting data sharing among users. We also put forward a software architecture for the Kylin Serveroriented Encrypting File System (KSEFS). At the end of the paper, we evaluate the file system, and the results show that, compared with the normal file services, the performance is reduced only by 3% to 18%.

  Data Sharing Based on Information Supermarket in the NetworkCentric Environment

  ZHANG Peng

  2011, 33(7): 6-11. doi:

  Abstract ( 414 )   PDF (713KB) ( 496 )   　　

  Data sharing is the core content of information resources management. The traditional pointtopoint way of data sharing features the defects: to increase the time necessary to establish new applications in the application system to an already existing link between the applications, to meet many troubles in different application system upgrades or interface changes, to remodify the connection between different applications at least, which do not lead to its flexibility. This paper presents a data sharing mode based on information supermarket. The mode makes the new information resources dynamically join without modifying the interfaces between systems.

  Design and Implementation of a MultiThreaded  BGP Model Based on Multicore Processors

  GAO Lei,LAI Mingche,GONG Zhenghu

  2011, 33(7): 12-17. doi:

  Abstract ( 494 )   PDF (892KB) ( 474 )   　　

  The urgent requirement for the highefficiency of routing protocols on the Internet will be satisfied by exploiting the threadlevelparallelism of BGP on multicores. A multithreaded BGP model is proposed based on neighbor session division, and it achieves the parallel processing of different sessions on multiple threads by the use of data parallelism. Firstly, the framework of the multithreaded BGP is put forward, and is then implemented based upon Quagga BGP. The experimental results on the Intel Xeon quadcore server show that, the multithreaded BGP yields the speedup of 2.73 in comparison with BGP, and can make full use of the computing resources on multicores to provide more performance improvement for the protocol.

  A Backward Search Approach to Attack Graph Generation Based on Attack Patterns

  ZHAO Bao1，ZHANG Yi2,MENG Yuan1

  2011, 33(7): 18-24. doi:

  Abstract ( 583 )   PDF (2996KB) ( 478 )   　　

  Automated generation of attack graphs always encounters efficiency problem when using attack graphs to analyse the vulnerabilities of large networks. This paper proposes a backward approach to attack graphs generation based on attack patterns with great efficiency. Firstly, we propose a novel model of network based on the key attributes of networks, which is improved upon the  previous models. This model optimizes the network connections and downsizes the network. Secondly, after abstracting a large number of vulnerabilities, we sum up a few attack patterns, based on which we build an efficiency approach to attribute attack graphs generation. Thirdly, the backward approach we propose solves the problem of loop attack paths. Finally, the experimental result shows that, our backward approach generates partial attack graphs which illustrate the potential interrelations among the known vulnerabilities just related to the given attack goal in the targeted network, while other forward approaches generate full attack graphs. And we show the experimental evidence that our attribute attack graph generation algorithm is very efficient, the complexity of the algorithm is between O(|H|2) and O(|H|3).

  Research on the Internet AntiMoney Laundering Technologies Based on Distributed Smart Agents

  FU Xiong

  2011, 33(7): 25-31. doi:

  Abstract ( 438 )   PDF (828KB) ( 397 )   　　

  To stop the fast development and internetization of money laundering crime activities, the Internet antimoney laundering technologies based on distributed smart agents are proposed, combined with data mining with the relationship graph entropy matrix. And an antimoney laundering simulation system is also developed.

  A Delay Tolerant Network Routing Algorithm Based on the Theory of Six Degrees of Separation

  LI Xiaofeng，WANG Guizhu，XU Zhenghuan

  2011, 33(7): 32-35. doi:

  Abstract ( 482 )   PDF (505KB) ( 482 )   　　

  Delaytolerant network (DTN) is an emerging research field. DTN is used to connect complex network environments in which nodes move randomly and network conects intermittently. The use of DTN requirs a  complex routing algorithm which is different from the existing networks. This article proposes a routing approach based on the theory of six degrees of separation, which forwards messages based on nodes’ social relationships described by using social activity and social closeness. It is indicated by the simulation results that this method features high delivery ratio and low delay rate compared to the existing routing algorithms.

  The  Fast Security Route Optimization Mechanism in Mobile IPv6

  YANG Jin,SHEN Pubing,SHEN Xiangyu,XING Mingshun

  2011, 33(7): 36-39. doi:

  Abstract ( 448 )   PDF (475KB) ( 406 )   　　

  The security of route optimization is a hot issue in MIPv6. Based on the description of the threats of route optimization and the analysis of the current protocols, an IDbased fast security route optimization is proposed. It can resist the redirection attacks, maninthemiddle attacks and DoS. It uses the symmetric encryption to generate the binding update authentication code, and improves the route optimization efficiency.

  The GPSR Algorithm for Geographical Location Based on Maximum Angle Points

  SUN Tao,HAN Ning,FENG Lin

  2011, 33(7): 40-44. doi:

  Abstract ( 514 )   PDF (691KB) ( 414 )   　　

  The algorithm of GPSR for WSN(wirelss sensor networks) transporting data to the same area, when it falls across a hole, the triangle routing problem occurs. So an improved strategy for GPSR based on the maximum transpond angle point(GPSRMTA) is proposed. When the data need to be sent, firstly, it will be sent according to GPSR. Under certain conditions, the point will calculate an angle. When the angle is the maximum, that point needs to send the message with the information about the maximum angle point to the source point. When the source point receives the message, it will set itself and its neighbor’s transpond information. Then the source point needs to send the message, it will send it to the transpond point, the maximum transpond angle point, after that, the message will be sent to the target point. The simulation shows that, this algorithm can go around the hole efficiently, and is improved on the average hops.

  Document Image Compression Performance Based on Block Matching

  SU Yunfei,LIN Jiayu,WANG Xiaofei,ZHANG Quan,TANG Chaojing

  2011, 33(7): 45-49. doi:

  Abstract ( 396 )   PDF (595KB) ( 441 )   　　

  Document Image is a kind of image which is used widely in our life, while it is different from the general images and texts, its local pixels change quickly and it has abundant high frequency, so that it is difficult to get a higher compression rate with the general compression methods. Using general compression methods to compress document images has poor performance because the particularity of the document image is not considered. According to the characteristics of Document Image, the method of Block Matching is used to get a much higher compression rate than the general compression methods which eliminate the redundancy via two dimensions. We first split a document image with a specific method and then classify and encode the image blocks. We describe the method of Block Matching in detail and analyze the performance, and then we show the result of simulation.

  The Fusion Change Detection of Remote Sensing Images Based on the DS Evidential Theory

  WANG Limin,LEI Lin,ZOU Huanxin

  2011, 33(7): 50-54. doi:

  Abstract ( 510 )   PDF (754KB) ( 473 )   　　

  Change detection at the pixellevel is use the original gray information of different temporal remote sensing images, which are registered previously, to find the change information of the environment. It is perspicuous and easytorealize, and is a generally applied change detection method. As far as the actual algorithm concerned, it can not work allaround among adaptability, robustness, accuracy, and timeeconomy. So in this paper, a novel fusion change detection method based on the DS evidential theory is introduced, which combines the results from different change detection algorithms by the DS fusion tactics and rules, and then the changes that are concerned can be detected at the decisionlevel. The results of the experiments show that the algorithm improves the accuracy and robustness of the change detection, reduces the choosing bound of the threshold, and decreases the impact of the threshold altering on the algorithm.

  Research of a Parametric Rapid Design System for the Combined Structural Sections

  LIU Yunhua，LIU Tianbing

  2011, 33(7): 55-61. doi:

  Abstract ( 552 )   PDF (1854KB) ( 436 )   　　

  To meet the requirements of the largescale engineering systems which need a parametric rapid design system for the combined structural sections. A system of parametric drawing for the combined structural sections has been designed and developed. The system based on the technology of the parametric design and the database of The Tianyu Part Library to draw a single structural section crosssection graph and transform the graph through a series of transformation matrices to get the combined graph.With a special blanking algorithm to support, the system achieves the projection view of the horizontal and vertical directions of the combined structural section by the combined graph’s database. This paper analyzes the system’s framework, and introduces the key technologies involved, such as the structural section of the combination, the location view of the structural section and the blanking algorithm of the projection view. An application example in a boiler enterprise is given.

  Reconstruction of the RippedUp Documents Based on Ant Colony Optimization

  HE Pengfei1,ZHOU Zongtan2,HU Dewen2

  2011, 33(7): 67-73. doi:

  Abstract ( 581 )   PDF (3009KB) ( 753 )   　　

  It is crucial to find a globally consistent solution for automatically reconstructing the rippedup documents.In this paper, we propose a global approach for reconstructing the rippedup documents based on Ant Colony Optimization (ACO). At first, partial matching is processed by using the  ψs analsys method with a high matching accuracy. The searching graph is constructed according to the ambiguous candidate matches and the pheromone is associated with the node. These pheromones are iteratively updated using the conflict between the candidate matches and the global trace constructed by ants: the pheromone is deposited beside the cadidate matches which are on the bestsofar path, and the pheromone evaporates beside the cadidate matches which are on the failure path. These pheromones converge and the proper cadidate matches are chosen according to the pheromones iteratively updated. The method is proved by the experiments.

  A Reshaped 2DPCA Algorithm Based on the Vertical Symmetry of Face

  ZENG Yue1,2,FENG Dazheng1

  2011, 33(7): 74-79. doi:

  Abstract ( 440 )   PDF (441KB) ( 485 )   　　

  this paper the vertical symmetry of face, the characteristics of PCA and 2DPCA are discussed. And it is proved that the covariance matrix of 2DPCA is equivalent to the average of the main diagonal of the PCA covariance matrix, and eliminates the covariance information that can be useful for recognition. A reshaped 2DPCA algorithm based on the vertical symmetry of face (S2DPCA) is proposed which can make the most useful of the covariance discriminate information, represents a face with  fewer coefficients. The experiments on the ORL face bases show it reduces the computational complexity compared with PCA, improve the recognition rate of face compared with PCA and 2DPCA, and is also superior to the traditional algorithms (ICA, eigenfaces and Keinel eigenfaces), and shows a face image with fewer coefficients.

  A New Color Image Spatial Domain ZeroWatermarking Algorithm Based on Image Normalization

  LIAO Qinan

  2011, 33(7): 80-84. doi:

  Abstract ( 471 )   PDF (643KB) ( 485 )   　　

  In order to achieve the copyright protection of digital color images, a geometrically robust image spatial domain zerowatermarking algorithm is proposed. Firstly, the green layer of the color image’s geometrically invariant space is constructed by using the  image normalization method．Then, the significant region is obtained from the normalized image by utilizing the geometric center. Finally, the zerowatermarking is constructed by performing the XOR(Exclusive OR) operation on the pixel of the watermark with another pixel randomly extracted from the significant region. The theoretical analysis and experimental results show that the algorithm’s performance is more stable than the watermarking algorithm based on the significant region obtained from the normalized image by utilizing the invariant centroid. Compared with the same class zero watermarking algorithm based on digital wavelet transform (DWT), it has a stronger ability of antishearing, geometric distortions, image processing and signal processing attacks.

  RealTime Rendering for  the PhongSpecular Surface by Multitexture

  ZHU Guozhong,ZHANG Fan，BU Hui

  2011, 33(7): 85-88. doi:

  Abstract ( 452 )   PDF (475KB) ( 452 )   　　

  The highlights of realworld objects are usually induced by specular reflection which has a complex nonlinear expression and brings difficulties to its realtime rendering. Therefore, a realtime rendering technology using texture mapping for the specular surface is proposed in this paper. In detail, the Phong BRDF model with a specular expression is decomposed into multiple precomputed functions, which are in turn stored as texture maps. Combining these textures by multitexture leads to substantial rendering for specular surfaces. The experimental results  show that our algorithm improves significantly the rendering performance.

  An Improved LDA Algorithm and Its Application to Face Recognition

  LIU Zhongbao

  2011, 33(7): 89-91. doi:

  Abstract ( 457 )   PDF (590KB) ( 507 )   　　

  Linear discriminant analysis (LDA) is a typical feature extraction method, but there exist at least two critical drawbacks in LDA: the small sample size problem and the rank limitation problem. In order to solve the above problems, this paper presents an improved LDA method (ILDA) which redefines the betweenclass scatter matrix and the withinclass scatter matrix. ILDA can effectively extract the discriminative information included in the null subspace and the nonnull subspace of a withinclass scatter matrix. Numerical experiments on some facial databases show ILDA achieves good performance of face recognition.

  A Survey of the VCR Methods in P2P Video on Demand

  LIU Bangchuan，TIAN Ye

  2011, 33(7): 94-100. doi:

  Abstract ( 440 )   PDF (639KB) ( 459 )   　　

  In recent years, the technology of P2P VOD has got a comprehensive development. It is widely accepted that people use a streaming media player based on P2P to play videos on Internet. But for many reasons, the users have to wait for a long time when they perform fast forward, fast rewind, and jump operations in playing videos, which is quite different from performing those operations on videos in local computers. Consequently, the users are not satisfied with it. In order to solve this problem, researchers propose many VCR solutions, which include the passive technologies and the active technologies. The passive technologies focus on reducing the time of locating the source node and downloading sources from it, at the same time, improve the possibility of saving the information of the source node. Active technologies focus on improving the possibility of the presaved content of video and the information of the source node. This paper plays emphasis on introducing the characteristics of these algorithms and comparing their merits and limitations. At the end, a view of the future development of VCR will be given in order to provide a reference to future study.

  EPSS:An Extensible PeertoPeer Streaming Simulator

  WU Jiqing,LIU Feng,PENG Yuxing

  2011, 33(7): 101-105. doi:

  Abstract ( 586 )   PDF (661KB) ( 393 )   　　

  As peertopeer streaming service on the Internet becomes more and more popular, simulators are necessary for the research and improvement of the peertopeer streaming systems. However, the existing simulators are all hard to extend their functions, which is inconvenient for research workers to achieve their goals. Therefore, we design and implement an Extensible PeertoPeer Streaming simulator: EPSS, which is an eventdriven, packetlevel and pythonbased simulator. In order to make EPSS extensible, we make a clear division of modules and extensible design of interfaces. The results of our experiments show that EPSS is not only easy to extend its functions but also scalable, so it is a better choice for the research workers of P2P streaming.

  A Parallel X264 Encoder Algorithm Based on the InterFrame and  IntraFrame MacroblockLevel

  WEI Feifei1，LIANG Jiuzhen1，HAN Jun2

  2011, 33(7): 106-111. doi:

  Abstract ( 540 )   PDF (866KB) ( 425 )   　　

  This paper studies the X264 encoder on the basis of a thorough knowledge about the H.264 standard, aiming to accelerate the encoding speed and enhance the encoder’s realtime ability. In the context of the data dependencies of the related macroblocks which are mainly analyzed, considering the characteristics of the parallel coding algorithm based on the macroblocklevel of InterFrame, the paper proposes a new multithread parallel coding algorithm. On the basis of the original multithread parallel algorithm of the interframe macroblocklevel and the following spatial correlation conditions,the algorithm which creates a thread for each row in the I frame,implements the parallel encoding of the interframe and intraframe macroblocklevel and achieves the effect of multigranularity parallelism.The experimental results illustrate that the propsed algorithm improves the encoding speedup while the video sequences are effectively encoded and with the PSNR holds basically unchanged.,and the realtime encoding is enhanced.

  A Fast Algorithm Based on Motion Classification and Direction Prediction

  CHEN Tianzhuang1,LIANG Jiuzhen1,HAN Jun2

  2011, 33(7): 112-117. doi:

  Abstract ( 388 )   PDF (1668KB) ( 487 )   　　

  This paper proposes a fast algorithm based on motion classification and direction prediction in which the spatialtemporal correlations of adjacent blocks’ motion vectors are used. The algorithm predicts the motion classification and relative motion of blocks and adaptively chooses different search method with motion classification information of blocks. For relative fast motion blocks, it predicts the motion direction and chooses corresponding search patterns. Experiments show that the algorithm can save more search time than other traditional algorithms with the same accuracy.