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  • 中国计算机学会会刊
  • 中国科技核心期刊
  • 中文核心期刊

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    • 论文
      Research on GPGPU performance models 
      WANG Feng,DU Yunfei,CHEN Juan
      2013, 35(12): 1-7. doi:
      Abstract ( 145 )   PDF (666KB) ( 284 )     

      The emerging and the development of the GPGPU afford the massive computation power to the parallel applications. How to use this computation power efficiently relies on the optimization of the applications. The performance models play an important roles on the targeting the performance bottleneck, guiding the optimization strategies, load balancing with other devices, etc. The stateofart of the GPGPU performance model is described, categorized, and analyzed in details. The models are divided into statisticbased curvefitting model and analysis model. The latter one can further be divided into metric model, computation and memory parallel aware model and componentbased quantitative model. The pros and cons of all the models are analyzed, and an interpolation performance model based on statistics is implemented. Finally the unsolved problems and the future challenges are presented.

      Optimization of small file access on
      object based parallel file system  
      ZHOU Enqiang,DONG Yong,ZHANG Wei,LU Yutong
      2013, 35(12): 8-13. doi:
      Abstract ( 179 )   PDF (687KB) ( 384 )     

      Object based parallel file systems are widely used in current supercomputers for its excellent performance of large file at the expense of its lower efficiency on small file access. Through analysis of the overhead of small file access on typical object based parallel file system, a serverside small file aware cache is proposed in order to reduce file access latency by aggressively prefetching a set of related files object and improving small file hit rate. This method is implemented and evaluated in Lustrefile system which is a popular parallel file system for HPC system. The experiments in real system show that it can improve the performance of small file access dramatically, especially with the reduction of up to 88% of total cost in scenario of file archiving operation.

      Discussing for supercomputing center power system         
      SONG Fei,YAO Xinan,HU Shiping
      2013, 35(12): 14-19. doi:
      Abstract ( 114 )   PDF (744KB) ( 226 )     

      With the expansion of the scale of high performance computer system,

      power consumption has become one bottleneck of its domain development. The key and the core

      of building green supercomputing center is energy efficient. Firstly, power system structure

      and its optimized project are described. Secondly, energy efficient policies are classified

      and described respectively. Moreover, synthetic energy management and scheduling for

      supercomputing center is conceived. Finally, we summarize and discuss future research

      directions.

      Research on desktop virtualization technology based on SPICE protocol and its improvement solutions            
      XU Hao,LAN Yuqing
      2013, 35(12): 20-25. doi:
      Abstract ( 227 )   PDF (543KB) ( 244 )     

      With the

      continuous development of cloud computing, the virtual desktop solution becomes increasingly

      mature and the desktop virtualization becomes a typical cloud computing application. Virtual

      desktop technology can effectively solve those problems when using traditional personal

      computers and also reduce maintenance costs, which draws industries' attentions. As an open

      source desktop delivery protocol, SPICE has its own unique architecture and characteristics.

      Using SPICE protocol, virtual desktops can be deployed between servers and remote terminal

      clients with good quality of user experiences. However, SPICE protocol has its own

      drawbacks, and it is not suitable for lowbandwidth networks. Virtual desktop technology is

      introduced and the theories of virtual desktop delivery protocols as well as factors that

      affect virtual desktop performances are analyzed. Based on the analysis, the architecture of

      SPICE virtual desktop solution and its core technology are further analyzed. Finally the

      drawbacks of SPICE protocol are pointed out and some improvements methods without affecting

      QoE are proposed, which will play a guide role for the development of virtual desktop

      technology.

      Research on comprehensive visualization method
      of molecular structure and gene sequence data  
      SONG Chenglong,ZOU Chen,WANG Wenke,LI Si
      2013, 35(12): 26-33. doi:
      Abstract ( 109 )   PDF (1060KB) ( 236 )     

      With the rise and the rapid development of system

      biology, in order to explore the relationship between different levels of Bioinformatics

      relevance, the need of comprehensive visualization of biological scientific computing data

      at different levels is increasingly urgent. A method of constructing an integration

      framework to realize the comprehensive visualization of molecular structure data and genomic

      sequence data is proposed. The visualization integration framework can achieve the unified

      management and unified GUI for different levels of visualization tools. By defining the

      method of describing the associated data, the framework realizes the integration of exiting

      molecular structure data and genomic sequence data and effectively supports the development

      of integrated function for visual molecular structure data and genomic sequence data. The

      method is used to develop a comprehensive visualization prototype system of molecular

      structure data and gene sequence data, realizing comprehensive visualization functions such

      as the synchronous display of both molecular structure data and genomic sequence data, and

      the display of the gene fragments and the local space structure of related molecular, and so

      on. Preliminary application and analysis show that the comprehensive visualization method is

      proposed with good scalability. The realized comprehensive visualization functions have good

      application prospects for studying the incidence relationship between molecular structure

      data and genomic sequence data.

      A dynamic worm propagation model
      based on social network  
      ZHAO Ying,YI Pingke
      2013, 35(12): 34-38. doi:
      Abstract ( 122 )   PDF (817KB) ( 328 )     

      In recent years, social networking worms

      propagating through users’ interactions appear frequently. These worms trick users to click

      worm links by exploiting social engineering techniques, and it poses a serious threat to the

      Internet. A dynamic worm propagation model based on social network is proposed, and the worm

      propagation process between network nodes is drawn out. Validity of the model is verified by

      the simulation, and the influence of the worm propagation is analyzed by the number of

      online users, the probability of users click worm links, the release time of immune patches

      and the quantity of users installed patches.

      A quick redirection strategy based on parent node
      backup mechanism in mobile ALM environment             
      CUI Jianqun1,YE Yongjia1,GAO Kuan1,FAN Jing2,WU Libing2
      2013, 35(12): 39-44. doi:
      Abstract ( 88 )   PDF (623KB) ( 173 )     

      To address solving

      the high dynamics problem of mobile Application Layer Multicast (ALM) nodes, a multicast

      system’s failure recovery strategy in the mobile environment is proposed. This strategy can

      achieve the goal of quick redirection by using active failure recovery method and the

      proposed redirection algorithm based on parent node backup. Besides, we propose to use the

      similarity of multicast tree to measure the impact of the redirection algorithm on the

      change of multicast system’s topology, thus evaluating the quick redirection strategy.

      Simulation experiment is given to show that the proposed quick redirection strategy has low

      delay and small influence on the multicast system's topology..

      RAS:Rate adaptation in IEEE 802.11 with receiver’s SNR       
      DENG Xiaoheng1,LI Xu1,LIU Qiang1,CHEN Zhigang2
      2013, 35(12): 45-51. doi:
      Abstract ( 119 )   PDF (886KB) ( 186 )     

      Rate Adaptation

      (RA) is designed to improve the performance of multirate feature in IEEE 802.11 PHY. One

      of the key issues in RA is to differentiate the channel error from linklayer collision,

      which is overlooked by many RA algorithms. Other than some RA algorithms that identify

      collisions at the transmitter by chances, we use receiver’s SNR to reflect the channel

      condition and mitigate the effect of collisions. A RA algorithm that utilizes ACK feedback

      mechanism is proposed to inform transmitter of receiver’s SNR so as to adaptively select

      the transmission rate. Simulation results show that our proposal mitigates the effect of

      collisions and performs well in respect of throughput and delay.

      Analysis of TCP performance in
      heterogeneous networks          
      YIN Qipeng,WU Chunqing,YU Wanrong,ZHAO Baokang,MA Yanpeng
      2013, 35(12): 52-57. doi:
      Abstract ( 90 )   PDF (1683KB) ( 253 )     

      At present, wired networks, wireless networks, satellite networks and high-speed

      networks all can carry the data payload, and the main features of heterogeneous networks are

      high BER (Bit Error Rate), long delay, asymmetry of bandwidth in some links, and so on.

      Since TCP is designed for normal wired networks so as not to work very well in heterogeneous

      networks. OPNET is used to simulate heterogeneous networks, and obtain the regular of how

      the BER, delay and asymmetry affect the TCP performance.  The obtained regular can provide a

      reference for experiments on optimization of TCP performance in challenged networks.

      A fair scheduling policy based on delay margin in wireless mesh networks             
      FU Qi1,2,CHEN Zhigang1,JIANG Yunxia2,YIN Fengyu2,LI Runqiu2
      2013, 35(12): 58-65. doi:
      Abstract ( 90 )   PDF (994KB) ( 212 )     

      In IEEE802.11ebased wireless mesh networks, the

      parameters (eg., contention windows, transmission opportunity) used in 802.11e's mechanism

      is statically assigned in order to guarantee the quality of service, which is more suitable

      to the communication nodes in one hop transmission with environment and not to the wireless

      multihop environment. In view of the problem that data flows with long delay bound may

      consume more channel time than data flows with short one so as to cause packet loss and

      networks performance degradation, a fair share scheme based on the residual packet delay

      bound, which is equally distributed among data packet, is proposed to alleviate the

      retransmission number and promote the fairness between data flows. Simulation results show

      that the proposed scheme is more effective than the original 802.11e protocol.

      An improved MMAC based MAC protocol for cognitive radio network              
      WANG Hui,GAO Ren
      2013, 35(12): 66-75. doi:
      Abstract ( 112 )   PDF (1178KB) ( 247 )     

      The cognitive radio network is proposed in the face of scarce spectrum resources

      and a variety of heterogeneous wireless access techniques. Media Access Control (MAC)

      protocol decides how the nodes in the networks receive and send data by shared wireless

      channels. Whether the MAC protocol can use the limited channel effectively or not plays a

      very important role in the performance of the cognitive radio network. Focusing on designing

      and implementing an excellent MAC protocol in cognitive radio networks, CRMMAC is

      proposed, which is an improved MAC protocol based on MMAC. In CRMMAC, there is a dedicated

      control channel. The network conditions, channel usage model, protocol frame structure and

      channel access strategy are presented. The simulation result shows that the proposed

      protocol has good performance.

      Detecting overlapping communities in complex networks    
      ZHANG Zhenyu,ZHANG Zhen,YANG Wenzhong,WU Xiaohong
      2013, 35(12): 76-83. doi:
      Abstract ( 125 )   PDF (1082KB) ( 250 )     

      Community detection is the key problem in studying complex network structure. An

      overlapping community detection algorithm SAEC based on edges is proposed based on the

      analysis of those existing means. The SAEC algorithm regards the community as a set of

      edges, defines the edge similarity and obtains the transition probability matrix. Using

      spectral clustering method, the number of communities is automatically determined by

      calculating the eigenvalues and eigenvectors of the transition probability matrix. Then, the

      overlapping community detection is completed by Kmeans algorithm. The effectiveness of the

      algorithm is verified by randomly generated test networks and real networks.

      Spectrum management based on random
      graph for cognitive radio Ad Hoc networks           
      ZHOU Jian1,2,3,YU Yong hong1,SUN Li yan1
      2013, 35(12): 84-89. doi:
      Abstract ( 86 )   PDF (1018KB) ( 220 )     

      Base station is not supplied to supported spectrum management for cognitive radio networks Ad Hoc, so communication among nodes may be failed because there is not a shared frequency between communication nodes. In order to deal with this question, a scheme of spectrum management based on random graph theory is proposed. Users select part of spectrums from the spare spectrum set whose number is computed by the parameter including spectrums size, network scale, link connection probability before joining in network. In communications the communication efficiency is not reduced even if every user’s spectrum resource is limited. In experiments the scheme guarantees the high probability of connective for each node having few frequencies; and the path of communication does not increase due to small spectrum scale. Therefore this scheme is suitalble to the surrounding that CR Ad Hoc network can be deployed quickly and flexibly.

      Research of IS-IS interoperability testing based on colored Petri nets           
      ZHAO Yulan,JI Chao,JIANG Fengxian,ZHU Yangyang,LEI Liting,ZHANG Zhibin
      2013, 35(12): 90-95. doi:
      Abstract ( 117 )   PDF (1058KB) ( 212 )     

      Internet has become an undivided part in modern life, therefore an effective and stable protocol becomes more and more important. The paper studies the interoperability testing of ISIS protocol, which is a major interior gateway protocol. Firstly, a hierarchical CPN model of the interoperability testing of ISIS protocol is established. Secondly, the full state space is automatically generated by the CPN tools, and test sequences and test cases are generated according to the test purpose. Finally, a test platform is built in Windows XP and a routing simulation software, named GNS 3, is used to imitate Cisco 7200, Cisco 3640, etc.. The obtained test cases are used to do the ISIS interoperability testing, and the test reports are given after the test results are analyzed.

      Research of AODV routing protocol based on
      link available time in the tactical MANET            
      ZHOU Jiao,TIAN Jie,DAI Chencheng,LI Tingjun
      2013, 35(12): 96-101. doi:
      Abstract ( 102 )   PDF (659KB) ( 212 )     

      Ondemand distance vector routing protocol AODV is one of the research hotspots in Ad hoc Networks. To ensure stable data transmission, a link available time algorithm of AODV is proposed, which increases a parameter of link available time in the route request packet and a parameter of routing path available time in the route reply packet. In the process of routing maintenance, intermediate nodes start the repair process before the link really fails. Compared with the traditional algorithm, the results obtained in NS2 simulation platform show that the improved AODV protocol enhances the reliability of the routing, improves packet delivery ratio and reduces the average endtoend transmission delay.

      Dynamic load balancing scenario based on
      multiobjective genetic algorithm             
      JIN Shan,LI Qiu
      2013, 35(12): 102-106. doi:
      Abstract ( 108 )   PDF (522KB) ( 261 )     

      The resource load balancing problem of the largescale and heterogeneous network is studied. Firstly, the problem is modeled and analyzed theoretically, and an objective function which satisfies the host and network constraints, is designed. Secondly, a multiobjective minimum spanning tree problem based on the model is researched, and a multiobjective genetic algorithm is devised accordingly. At last, a dynamic load balancing scenario named DSMG is proposed based on the algorithm. The simulation results show that the DSMG can balance the load effectively between the lightload nodes and the overload ones by selecting the appropriate parameters. Besides, both the resource consumption rate and the quantity proportion of the bottleneck nodes perform quite well compared with other dynamic load balancing scenario. 

      An optimization algorithm for
      largescale Internet recommender system  
      JIANG Peng,XU Feng,ZHOU Wenhuan
      2013, 35(12): 107-113. doi:
      Abstract ( 118 )   PDF (750KB) ( 272 )     

      Recommender system is one of the key techniques in internet applications. The system analyzes user’s behavior, and recommends products initiative to replace the passive acceptance of user requests. The recommender system can improve not only the user experience but also the user’s desire to buy something. Collaborative filtering algorithm is widely used in the recommender system. In a largescale network, traditional collaborative filtering algorithms have extreme sparseness problem, and thus being inefficient. A collaborative filtering algorithm is proposed, which is designed by the largescale network segmentation rules. The algorithm uses the idea of divide and conquer algorithm, and decomposes problems into subproblems to solve, hence reaching the optimization of algorithm.

      An adaptive message pushing strategy for mobile devices         
      LIU Yongling,LIU Wu,GUO Kehua
      2013, 35(12): 114-119. doi:
      Abstract ( 115 )   PDF (590KB) ( 208 )     

      Considering device diversity, power consumption, network flow consumption and message realtime in mobile devices, an adaptive message pushing strategy in mobile network is proposed. In the strategy, the running parameters of mobile device are obtained to determine the message pushing mode, and then the dispatching module will automatically convert the approach between the pollingbased and the connectionbased communication. Experiment results show the strategy can solve the terminal diversity problem, ensure the message realtime and save the power and network flow consumption in comparison to some traditional message pushing strategies.  

      A dynamic updating method of user experience time of Web services           
      JU Xinglong1,DUAN Youxiang1,MA Cheng1,XIU Nanhai1,JU Haiyan2
      2013, 35(12): 120-125. doi:
      Abstract ( 88 )   PDF (644KB) ( 206 )     

      Web services can not be used without the QoS information. The values of Web services’ QoS attributes are dynamic, such as user experience time. With respect to the static QoS attribute values, the dynamic QoS attribute values can reflect the actual quality status better. A new dynamic updating method, called HDBQoSDPM, of user experience time of Web services is proposed. Classic Web services model does not include the QoS information. In order to verify the correctness of the method, a Web services model, named QoSBWSA, is proposed. In the QoSBWSA model, QoS information processing function is included. The experiment shows that the proposed updating method is feasible and correct.

      Digital watermarking encryption
      algorithm based on chaotic system       
      WU Jing,JING Fengxuan,QI Fumin
      2013, 35(12): 126-133. doi:
      Abstract ( 164 )   PDF (1063KB) ( 302 )     

      Aiming at the issues that robustness and security of most image watermarking are not strong,a digital watermarking algorithm based on multifactor encryption and Contourlet transform is proposed. Using the good pseudo randomness and mathematical statistical characteristics and the advantages of simple and quickly generated sequences of Chebyshev map, three chaotic sequences are produced. Two of them are used to encrypt the watermarking image, the left one is used as watermarking embedded keys; The Contourlet Transform is used to extract the subband coefficients of the original carrier and the encrypted watermark, then the coefficients of the watermark is embedded into the coefficients of the original carrier, thus accomplishing the watermark embedding process. The method is implemented and experiments are performed to compare the proposed method with other methods in literatures. The result shows that the algorithm owns better effect on robustness, security and invisibility.