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Table of Content

    01 March 2011, Volume 31 Issue 03
    Network and communications
    Cross-link-tolerant topology partition detection for MANET
    REN Zhi ZU Li CAO Jian-ling HUANG Yong
    2011, 31(03):  587-590.  DOI: 10.3724/SP.J.1087.2011.00587
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    To detect the critical nodes that can lead to topology partition in a Mobile Ad Hoc Network (MANET), a Cross-link-tolerant Partition Detection Algorithm (CPDA) was proposed. Through utilizing the information of adjacent nodes, CPDA could eliminate the cross-links' impact on the elementary loop. Therefore, it solved the problem that the existing algorithm of Distributed Partition Detection Protocol (DPDP) based on elementary-loop could not address cross links, which improved the accuracy of detection of critical nodes. The performance results show that CPDA has no limitation on network topology and outperforms DPDP in terms of detection accuracy and overhead.
    Topology modeling algorithm for weighted directed network based on triad formation rule
    YUAN Wen-ju LI Fei-peng SUN Xin FU Feng LIU Yan-heng
    2011, 31(03):  591-593.  DOI: 10.3724/SP.J.1087.2011.00591
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    Topology generation algorithm of weighted directed network based on the triad formation rule was proposed. The directed edges were added to the network using weight preferential attachment rule and triad formation rule; moreover, the weights of network edges were evolved dynamically to realize the asymmetric interaction among nodes. The simulation results show that, the network topology, which is generated by the modeling algorithm for weighted directed network topology based on the triad formation rule, is consistent with topology characteristics showed by topology structures in the real network environment. Meanwhile, it has good controllability of the clustering coefficient.
    Research of stochastic scheduling algorithm for wireless sensor network
    LI Jie CHEN Xi
    2011, 31(03):  594-597.  DOI: 10.3724/SP.J.1087.2011.00594
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    The limited node energy, high node redundancy and other characteristics of Wireless Sensor Network (WSN) make working-in-round mechanism one of the basic policies in solving the network coverage problem. In this paper, the authors investigated the network characteristics of stochastic scheduling model, analyzed the relationship between the number of effective nodes and rotation cycles, and finally provided an adaptive algorithm to adjust the node work probability according to the effective node number in the network. The algorithm can solve the performance problem in the later periods of the network, which is caused by reduction of effective nodes and static work probability, and thus guaranteeing the network performance in each round. Simulation verifies the effectiveness and correctness of the novel algorithm.
    Research on suppressing control messages in Ad Hoc on-demand distance vector based on directional broadcast
    WEI Zhi-ren SHAN Zhi-Long
    2011, 31(03):  598-601.  DOI: 10.3724/SP.J.1087.2011.00598
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    In Ad Hoc On-Demand Distance Vector (AODV) protocol, it broadcasts Request messages omnidirectionally and Hello messages periodically to build up the routing in Ad Hoc networks. But during the routing discover phase, it needs to broadcast large amount of Request messages, which weakens the performance of AODV. In this paper, a new routing protocol based on the directed broadcasting was presented. A Request message was sent through directed broadcasting, and the interval of sending Hello messages was adjusted dynamically according to the node mobility. The theoretic analysis and simulation show that the proposed scheme can reduce both the number of control messages and the routing load effectively. Besides, the performance parameters such as end-to-end delay and average deliver ratio have been improved significantly.
    Spectrum allocation algorithm of graph coloring theory based on user requirement
    QU Yue XIAN Yong-ju XU Chang-biao
    2011, 31(03):  602-605.  DOI: 10.3724/SP.J.1087.2011.00602
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    This paper analyzed the latest spectrum allocation algorithms of graph coloring theory. Concerning the shortage of the cognitive users' requirement not being satisfied, the user-satisfaction was proposed. Based on it, the authors set the spectrum allocation priority function. And the users, whose need was not well satisfied, were preferentially assigned. A spectrum allocation algorithm of graph coloring based on the requirement was obtained. The simulation results show that the proposed algorithm can enhance the system's channel efficiency, meet the needs of multiple users' bandwidth requirements better, and improve the spectrum efficiency.
    Power allocation algorithm with QoS-requirements in multi-user relay networks
    YAN Jing-lin TANG Lun CHEN Qian-bin CHEN Bo
    2011, 31(03):  606-608.  DOI: 10.3724/SP.J.1087.2011.00606
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    To study the fairness-optimization problem with different user-rate in non-regenerative relay network, a power allocation algorithm based on user-required rate proportional fairness was proposed. Because the source could not receive the messages of the user's hope rate, a pre-average allocation fairness algorithm was proposed to overcome the disadvantage of the prior algorithm. The simulation results show that the two algorithms realize goal of minimizing the difference between user-rate and required rate and save the resource in network with assuring the users' requirement of Quality of Service (QoS).
    Feedback load balancing algorithm based on B+ tree fast tuning
    WANG Zheng-xia LIU Xiao-jie LIANG Gang
    2011, 31(03):  609-612.  DOI: 10.3724/SP.J.1087.2011.00609
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    With the rapid development of Internet bandwidth, the parallel processing technique can greatly improve the performance of network intrusion detection system. Network Intrusion Detection System (NIDS) in parallel environment requires complete connection while balancing the traffic load. That is, packets belonging to one session should go to the same processing node. Based on the stability and balance characteristics of B+ tree, this paper proposed a feedback load balancing algorithm based on B+ tree fast tuning. B+ tree has characteristics of high search efficiency and stability. This algorithm tuned the B+ tree structure and remapped flow table when unbalanced. The simulation results show that this algorithm is able to balance the connection density of B+ tree, achieves a really satisfactory balance of the sensors' load and reduces the packet loss rate.
    Fast relay selection algorithm based on symbol error probability
    SUN Lin MA She-xiang
    2011, 31(03):  613-616.  DOI: 10.3724/SP.J.1087.2011.00613
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    Concerning the problem between the optimality and efficiency of the relay selection algorithm, an algorithm of the relay selection based on fast symbol error probability was proposed in Amplify-and-Forward (AF) cooperative networks. First, with the equal power allocation, and based on the statistic channel information and symbol error probability of the system, an equivalent channel gain was brought in. The parameter described the compositive channel character of two phases that were the source node to relay node as well as relay node to the destination in the cooperative process. Then with the descending order of the parameter, the Signal-to-Noise Ratio (SNR) could be taken as the threshold, and different relay node set was chosen to minimize the symbol error probability in case of equal power allocation. And combined with the near optimal power allocation, the proposed scheme further reduced the symbol error probability. As shown in the simulation results, the error probability performance of this relay selection scheme is similar to the optimal full-search scheme but the complexity is reduced to at least 1/20 of the latter one. And it also shows that the error probability of the proposed scheme is lower than the other schemes such as all participating amplify-and-forward (AP-AF) relay selection and pre-select single relay amplify-and-forward (S-AF) relay selection.
    Optimized design for network-on-chip router
    WANG Jian LI Yu-bai PENG Qi-cong
    2011, 31(03):  617-620.  DOI: 10.3724/SP.J.1087.2011.00617
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    For the Network-on-Chip (NoC) with virtual-output-queue router architecture, a design method to customize the buffer size for each virtual channel was proposed, so that the NoC communication performance was improved. With the restriction of limited buffer resources that could be used in NoC, the effect of virtual channel buffer size on the average packet latency in NoC was analyzed, and then a buffer allocation algorithm was proposed and buffer resources were allocated to the bottleneck of NoC. It thus improved the NoC performance without additional buffer resources cost. Finally, the effectiveness of the optimization design method was validated by simulation and the performance of NoC with optimized router was compared with the performance of NoC with un-optimized router.
    Research and application of dual-link communication mechanism for wireless mobile environments
    LIN Wei-yi CHEN Bing
    2011, 31(03):  621-624.  DOI: 10.3724/SP.J.1087.2011.00621
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    Problems such as high delay, high packet loss rate, low stability and reliability exist in current handoff scheme. To solve these problems, a dual-link communication mechanism and a dual-link selection were proposed, and the data transmission algorithm was presented in this paper to acquire accurate signal quality by smooth processing and control the handoff between two communication links at appropriate time by threshold of difference value and packet forwarding using dual-thread. The experimental results show that compared with the single link mechanism, no delayed pulse exists in dual-link mechanism, the packet loss rate is close to zero and the average throughput is increased by 20%. This mechanism can be applied to many environments owing high-speed mobile subnet such as metro, highway, etc.
    Multi-constrained QoS routing protocol based on clustering for wireless Mesh network
    SUN Zhi
    2011, 31(03):  625-628.  DOI: 10.3724/SP.J.1087.2011.00625
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    The rapid growth of multimedia applications makes it important and significant to provide Quality of Service (QoS) guarantee for Wireless Mesh Network (WMN). Combined with the characteristics of WMN, a computing method of routing metrics was designed, and then a clustering-based multi-constrained QoS routing (CMQR) was proposed. The intra-cluster route was computed parallel by root node and was connected by gateway-links, which reduced routing calculation and improved scalability of the protocol. The simulation results show that CMQR protocol can effectively reduce route establishing time and routing overload, but the packet delivery ratio remains high.
    TDOA location algorithm based on Elman neural network
    WU Yan-hong GUAN Wei-guo WANG Yan-feng
    2011, 31(03):  629-631.  DOI: 10.3724/SP.J.1087.2011.00629
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    Concerning Chan location algorithm's poor performance in Non-Line-of-Sight (NLOS) environment, a Chan location algorithm based on the Elman neural network was proposed. The Elman neural network was adopted to correct the NLOS errors with its dynamical characteristics and non-linear approach capacity and then the position was calculated by Chan's algorithm. The simulation results indicate that the location algorithm can improve the performance even in serious NLOS environment. The performance of the proposed algorithm outperforms that of Chan's algorithm and Taylor's algorithm.
    Research of chaotic spread spectrum ranging schemes
    HE Shi-biao BAI Jie LUO Dong-mei XIAO Li-li
    2011, 31(03):  632-635.  DOI: 10.3724/SP.J.1087.2011.00632
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    Chaotic sequence, with its good correlation performance, being sensitive to initial condition and hard to be decrypted, has been used as an ideal spread spectrum code in direct spread spectrum communication system. In order to take full advantages of the chaotic sequences ranging, based on the analysis of the basic principle of the pseudo code ranging and by using the digital matched filter to achieve the chaotic sequences acquisition, two chaotic spread spectrum ranging schemes were designed and their ranging processes, acquisition time and ranging accuracy were analyzed. The results show that taking the chaotic code as the spread spectrum code of ranging is feasible, with the strongpoint of high security, low interception, and it is also suitable for multi-target ranging, etc.
    Time delay estimation algorithm for narrowband audio frequency signal
    LUO Jin-wen HU Zheng-wei JIANG Zhan-jun YANG Gui-qin JIAO Fang-fang
    2011, 31(03):  636-638.  DOI: 10.3724/SP.J.1087.2011.00636
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    The issue of time delay estimation of narrowband audio frequency signal was studied, the signal model of time delay estimation was given, the traditional time delay estimation method of generalized correlation and the time delay estimation method based on the Hilbert transformation were studied, and then, a time delay estimation method based on the fractional Hilbert transformation was constructed in this paper. Finally, the mean square error curve of time delay estimation based on different fractional order was given through computer simulation. In the best case, compared with the estimation method of generalized correlation and Hilbert transformation, the simulation results show that the fractional Hilbert transformation method has better performance.
    Construction of asymptotic optimal LCZ sequence pairs set
    SHI Reng-hui ZHAO Xiao-qun LI Li-zhi
    2011, 31(03):  639-642.  DOI: 10.3724/SP.J.1087.2011.00639
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    Best binary sequence pair exists in a lager scope than perfect binary sequence, for the sake of enlarging the address code selection of Quasi-Synchronization Code Division Multiple Access (QS-CDMA). Two methods of constructing sequence pairs set of asymptotic optimal Low Correlation Zone (LCZ) were proposed. A kind of asymptotic optimal LCZ sequence pairs set was constructed based on perfect binary sequence pair with modified Walsh sequences set (or m-sequence's cyclic shift sequences set) and a set generated by the cyclic shift sequences of a binary sequence pair with two-level periodic autocorrelation. The asymptotic optimal LCZ sequence pairs set constructed have more various parameters combinations. It can provide more choices for engineering application.
    Transmit antenna selection based on log-likelihood ratio
    ZHANG You-yan
    2011, 31(03):  643-646.  DOI: 10.3724/SP.J.1087.2011.00643
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    The antenna diversity based on Log-Likelihood Ratio (LLR) is a new technique which is better than that based on Signal-to-Noise Ratio (SNR) in code-error rate performance, and it provides a significant reduction in complexity and cost. In this paper, the new technique of transmit antenna selection based on LLR was studied and the expressions of transmit antenna selection schemes based on Symbol-LLR (SLLR) and Bit-LLR (BLLR) over Multi-Input Multi-Output (MIMO) Nakagami channel were derived. At the same time, the average Bit-Error Rate (BER) performance of M-ary modulated system was studied. The simulation results show that the BLLR scheme is optimum since it minimizes the BER of MIMO system. With the same total number of antennas, the system which possesses the higher diversity order exhibits better performance. Moreover, with the same diversity order, the BER performance is more preferable due to the higher number of receive antennas.
    Artificial intelligence
    Data association algorithm based on intuitionistic fuzzy clustering
    HE Zheng-hong LEI Ying-jie LEI Lei
    2011, 31(03):  647-650.  DOI: 10.3724/SP.J.1087.2011.00647
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    To deal with the uncertainty of multi-sensor observations, a new data association algorithm based on intuitionistic fuzzy clustering was proposed. The clustering algorithm of improved Intuitionistic Fuzzy C-Means (IFCM) was applied to data association in the proposed algorithm. Firstly, the observed data and predicted data were made to be intuitionistic fuzzy. Then the weighted distance between intuitionistic fuzzy sets was calculated to acquire membership degrees of observation and track. Finally, the highest degree of membership was sought successively to associate observation and track. The simulation results show that the presented algorithm can associate data with the fuzzy observations effectively.
    Shortest path search in road network with incomplete information
    LONG Ke-jun Lee. D. HAN WANG Sai-zheng
    2011, 31(03):  651-653.  DOI: 10.3724/SP.J.1087.2011.00651
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    Concerning the incomplete information, structural characteristics and driver's habit, issue of the shortest path search in road network was studied. A mixed programming was proposed combining the global and local planning. During global planning, an index d/l was introduced which represented the ratio of Origin-Destination (OD) distance to the average link length, elliptical minimal search area was determined by d/l, and the initial global shortest path was calculated by Dijkstra algorithm. During local planning, an improved Bug algorithm was introduced based on network structure and influence range of unexpected events, and the congested or hazard region along the global planned path was avoid. The simulated experimental results indicate that the mixed planning can search the shortest path dynamically in road network with incomplete information and evade from congestion efficiently.
    Cooperative Q learning method based on π calculus in robot soccer
    KE Wen-de PIAO Song-hao PENG Zhi-ping CAI Ze-su YUAN Quan-de
    2011, 31(03):  654-656.  DOI: 10.3724/SP.J.1087.2011.00654
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    Concerning the low speed and low efficiency of learning in robot soccer when cooperating between multi-robots, a cooperative Q learning method based on the mental model of π calculus was proposed, in which the mental states were defined as the field state, goal, intention, action, cooperation, request, expanding knowledge,capability judging and connected intention, etc, and the combinational reward function was constructed. The validity of method was verified through experiments.
    New group search optimizer algorithm based on chaotic searching
    FANG Zhen-guo CHEN De-bao
    2011, 31(03):  657-659.  DOI: 10.3724/SP.J.1087.2011.00657
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    To improve the performance of Group Search Optimizer (GSO), a new group search optimizer algorithm based on Chaotic Group Search Optimizer (CGSO) in combination with the global searching characteristic of the chaos method was proposed in the paper. In the method, the good position of producer was updated by chaotic searching, the new position of scrounger was determined by the position of producer and the best position which it had been achieved so far, and the new position of rangers was achieved by chaotic mutation. The global convergent performance of GSO was improved by using the initial sensitivity of the Logistic map to expand the scope of the search and by employing the global ergodicity to search the positions. Four function optimization problems were simulated by CGSO and GSO. The experimental results indicate that CGSO is more effective than the others.
    Muti-population coevolutionary algorithm for numerical optimization
    PENG Fu-ming
    2011, 31(03):  660-665.  DOI: 10.3724/SP.J.1087.2011.00660
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    To improve the anti-premature ability and efficiency of evolutionary algorithm, a new algorithm based on multi-population was proposed. According to the heterotic theory, the algorithm made multi-populations concurrently evolve. The populations were both relatively isolated and cooperative to keep the diversity of populations. As a metaphor for creatures breeding in different habitats, different populations used different operators. Such a setting balances the breadth and depth of the algorithm, which made the algorithm to be converged to global optimal solutions. The good performance of the presented algorithm was validated in the experiments as well.
    Automatic batch-organizing algorithm of associated tracks based on desired degree
    YAN Jun XU Bao-guo WANG Yue SHAN Xiu-ming
    2011, 31(03):  666-669.  DOI: 10.3724/SP.J.1087.2011.00666
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    In the distributed data fusion architecture, the general batches should be organized to make local tracks be correspondent with systemic tracks, after local tracks are associated in fusion center. Thus, following tracks' fusion can be dealt conveniently. In the practical engineering systems, the association mistakes can make the following automatic algorithm for organizing batches invalid, and cause systemic tracks intermittent and fail to work. An automatic algorithm for organizing batches of associated local tracks was proposed. In this algorithm, the local tracks would be distributed with general batches according to the desired degree between association of tracks and fusion of tracks. It could make the association tracks be correspondent with the systemic tracks. Besides reflecting real associated relationship, the proposed algorithm also guaranteed the stability of fused tracks batches and made the batch represent the same object in different time. The proposed algorithm has been applied into the practical engineering system, and it has good stability.
    Database technology
    Maintenance and optimization methods of large rule network
    ZHANG Gui-gang
    2011, 31(03):  670-673.  DOI: 10.3724/SP.J.1087.2011.00670
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    Based on the requirements of processing a large sale of rules, a maintenance and optimization method of a large rule network was proposed. The basic calculation steps of incremental integrated and removal rules maintenance were put forward and a set of rule module replacement optimization methods were proposed to improve processing efficiency. Finally, the rule network optimization methods were illustrated by some examples. The maintenance and optimization methods of a large rule network extend the existing rule network processing pattern and propose new processing method.
    Improved text clustering algorithm of probabilistic latent with semantic analysis
    ZHANG Yu-fang ZHU Jun XIONG Zhong-yang
    2011, 31(03):  674-676.  DOI: 10.3724/SP.J.1087.2011.00674
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    Trained by the Expectation Maximization (EM) algorithm, whose model parameters are randomly initialized, the performance of Probabilistic Latent Semantic Analysis (PLSA) model is quite dependent on the initialization of the model, and the result of iteration is not a global maximum, but a local one. The authors derived probabilities from Latent Semantic Analysis (LSA), and then used it to initialize the parameters of PLSA model in documents clustering. The improved PLSA could effectively solve the puzzle of random initializing of EM. It is shown that the improved algorithm has a distinct improvement in Normalized Mutual Information (NMI) and accuracy.
    I/O matchmaking optimization method of semantic Web service with efficient index
    FENG Yong FANG Xin XU Hong-yan
    2011, 31(03):  677-679.  DOI: 10.3724/SP.J.1087.2011.00677
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    A great deal of Web services and requests exist in Web environment. Web services matchmaking based on semantic can improve accuracy of service discovery. Because of complicated semantic calculation, the reaction rate of Web service matchmaking was slow. Firstly, this paper analyzed the process of semantic Web service matchmaking to make clear that the large amount of semantic calculation exited in Inputs/Ouputs (I/O) matchmaking phase. Secondly, an I/O matchmaking optimized method of semantic Web services with efficient index was put forward on the basis of the studies on I/O matchmaking algorithms and main influence factors of semantic similarity, which included the creation of efficient index and the raise of the heuristic filter mechanism based on the re-hash secondary detection. Finally, the proposed method was proved to be feasible and rational via an instance. The proposed method can reduce semantic calculation and promote reaction rate by filtering some irrelevant Web services. Furthermore, the experience of users can be improved.
    Application of K-Means clustering of kernel to ambiguity and redundancy of tag in Folksonomy
    ZHANG Xin-lun SU Yi-dan HUI Gang-gang
    2011, 31(03):  680-682.  DOI: 10.3724/SP.J.1087.2011.00680
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    Ambiguity of tag may give a false impression of success when the recommended tags offer little utility. Redundancy of tag can hamper the effort to judge recommendations as well. When using K-Means clustering to deal with this problem, the extraction of ambiguity tags and redundancy tags was inaccurate because the clustering effect was ineffective. Therefore, the K-Means clustering of kernel algorithm was used to deal with the problem of ambiguity and redundancy on tags. This approach improved the clustering effect because it could identify, extract and enlarge useful features of the sample by non-linear mapping. The experimental results show that, the K-Means clustering of kernel algorithm has better performance in the clustering of tag and resource, and the extraction of ambiguity tag and redundancy tag is more accurate.
    Attribute mapping search algorithm based on combined similarity calculation in data integration
    ZHENG Kai LIANG Zhuo-ming ZHENG Wen-dong
    2011, 31(03):  683-685.  DOI: 10.3724/SP.J.1087.2011.00683
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    In view of the problem of attribute mapping techniques in materialized data integration, the authors proposed a search algorithm of attribute mapping based on combined similarity calculation (SACS). The proposed algorithm was established through intuitive calculation factors and combined formula to traverses attribute mapping in data sources. The algorithm avoids the sample selection problem of machine learning in traditional attribute mapping techniques, and improves the precision rate and recall rate for attribute mapping.
    Mining association rules of geographic information system based on concept lattice
    CHEN Xiang WU Yue
    2011, 31(03):  686-689.  DOI: 10.3724/SP.J.1087.2011.00686
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    Mining the hidden knowledge in the spatial data of Geographic Information System (GIS) is an important direction in the study fields of GIS and data mining. The technique of concept lattice is very important in finding association rules. In this paper, an algorithm of building concept lattice based on incremental method was proposed to improve the speed of building lattice by comparing the extent of the concept and introducing support constraint. It could also simplify the lattice and make it easier to mine rules. To expand the application of the algorithm, it was applied in finding association rules of the spatial data in GIS and got practicable application result.
    Cache replacement method based on lowest access cost for location dependent query
    LU Bing-liang MEI Yi-bo LIU Na
    2011, 31(03):  690-693.  DOI: 10.3724/SP.J.1087.2011.00690
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    Because of the user's mobility and the location dependency of data, new challenge has been brought to cache replacement strategy for Location Dependent Query (LDQ). Based on the detailed analysis of the space location characteristics of Location Dependent Data (LDD) and several typical replacement strategies of location dependent cache, the authors proposed a prioritized approach cache replacement based on the lowest access cost (PLAC), the PLAC took some important factors into account such as access probabilities, update rates, data distance, valid scope. To ensure the maximum utilization of limited cache, the PLAC cache replacement strategy decided which data would be replaced according to the value of the lowest cost function. The contrast experiments show that the PLAC increases cache hit rate and shortens query average response time more effectively than other location dependent cache replacement strategies.
    Outlier detection algorithm based on variable-width histogram for wireless sensor network
    JIANG Xu-bao LI Guang-yao LIAN Shuo
    2011, 31(03):  694-697.  DOI: 10.3724/SP.J.1087.2011.00694
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    The accuracy of sensor data is a critical index to evaluate the performance of Wireless Sensor Network (WSN). Outlier detection is a crucial but challenging issue for WSN. In this paper, an outlier detection approach based on variable-width histogram was proposed. The dynamic sensor data were aggregated into variable-width histograms, which avoided unnecessary data transmissions while detecting outliers. The theoretical analysis and evaluation on real WSN dataset show that this approach has high detection accuracy, and the cost is effectively reduced.
    Word sequence kernel applied in spam-filtering
    CHEN Xiao-li LIU Pei-yu
    2011, 31(03):  698-701.  DOI: 10.3724/SP.J.1087.2011.00698
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    The structure of the text is neglected by using the majority of used kernels to classification, so that a lot of semantic information is lost. In order to solve this problem, a Word Sequence Kernel (WSK) based on dependence measure was proposed and used in the field of spam filtering in this paper. Firstly, the features of each E-mail were extracted and the dependence measure of each feature was calculated; then the word sequence kernel was used as kernel function to train Support Vector Machine (SVM), and the decay factor of each feature was calculated by taking the dependence measure of each feature into account in the training process; finally, the optimized SVM filter was used to spam filtering. The experimental results show that the improved word sequence kernel gets higher accuracy compared to the commonly used kernels and string subsequence kernel. The proposed method improves the accuracy of spam filtering.
    Prediction of gas concentration based on K-Means clustering
    MU Wen-yu LI Ru
    2011, 31(03):  702-705.  DOI: 10.3724/SP.J.1087.2011.00702
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    A prediction model of non-linear time series based on K-Means clustering was proposed. Using the ability of short-term predicting for chaotic time series, the paper constructed a gas concentration prediction model for certain coal mines. Correlation integral method was used to determine the time delay τ and dimension m. After the phase space was reconstructed, the weighted one-rank local-region method based on K-Means clustering was used to construct prediction model. The experimental results show that, if next one minute data will be forecasted, it is more appropriate to use a continuous 200 training data to determine parameters τ and m for predicting better results, the error reaches 0.0341; if next few minutes data will be forecasted, it is more appropriate to use a 200 training data with 15 minutes intervals for predicting better results, the error is 0.0437. It shows that the timing of the gas concentration restores the initial chaos after 15 minutes.
    Graphics and image technology
    Study on adaptive ability of Gaussian mixture background model
    ZHANG Yun-chu SONG Shi-jun ZHANG Ru-min HAO Jian-lin
    2011, 31(03):  706-709.  DOI: 10.3724/SP.J.1087.2011.00706
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    Gaussian mixture background model is an online parameterized statistical model, and the presenting way of pixel sample pattern observed from time window has great influence on the model's learning result. According to the characteristics of dynamic background changes, issues such as the stability and plasticity of modal learning, the modal residual and activation, which affected the model's adaptive ability, were studied. The simulation results show that Gaussian mixture background model has a robust selective adaptability to gradual change, but a limited adaptability to transient variation of background configuration provided by modal residual and activation mechanism.
    Blind image restoration based on improved Kalman filter
    WANG Lei FENG Xiao-yi WAN Xiao-na
    2011, 31(03):  711-714.  DOI: 10.3724/SP.J.1087.2011.00711
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    To eliminate or reduce the image degradation, the image restoration techniques are often used. In this paper, a new image restoration way was obtained for blind image. Firstly, the Point Spread Function (PSF) of blurred image was estimated by cepstrum. Secondly, the blurred image was restored by the improved Kalman filter. The cepstrum was the way that the PSF of blurred image could be obtained through analyzing the relationship between two parts. One reflected original image, and the other reflected blurred system. The improved Kalman filter took account of the model error of system during the process of estimation. Some digital simulation experiments were done through Matlab. The results using the improved Kalman filter algorithm based on estimated PSF indicate that the proposed method effectively eliminates the impact caused by inaccurate PSF and it has better effects than Kalman filter.
    Feature extraction based on supervised locally linear embedding for classification of hyperspectral images
    WEN Jin-huan TIAN Zheng LIN Wei ZHOU Min YAN Wei-dong
    2011, 31(03):  715-717.  DOI: 10.3724/SP.J.1087.2011.00715
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    Hyperspectral image has high spectral dimension, vast data and altitudinal interband redundancy, which brings problems to image classification. To effectively reduce dimensionality and improve classification precision, a new extraction method of nonlinear manifold learning feature based on Supervised Local Linear Embedding (SLLE) for classification of hyperspectral image was proposed in this paper. A data point's k Nearest Neighbours (NN) were found by using new distance function which was proposed according to prior class-label information. Because the intra-class distance is smaller than inter-class distance, classification is easy for SLLE algorithm. The experimental results on hyperspectral datasets and UCI data set demonstrate the effectiveness of the presented method.
    Parameter optimization for balloon force Snake model based on parallel genetic algorithm
    ZHAO Yu-qian LIU Chui
    2011, 31(03):  718-720.  DOI: 10.3724/SP.J.1087.2011.00718
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    The image segmentation effect of balloon force Snake model largely depends on the initial parameters' selection. A new method based on Genetic Algorithm (GA), which is efficient, parallel and global searching, was proposed to solve the selection of optimal parameters. In this paper, the parallel genetic computation was used to calculate optimal parameter, the energy function of Snake was used as an object function, and the image similarity function was used as the criteria to stop genetic iterating. The results of real medical images prove that the proposed method can avoid the trivial of selecting parameters artificially through a large number of experiments, also solve the problem of not ideal result caused by unsuitable parameters' values, and it can get excellent segmentation effect.
    Behavior classification algorithm based on enhanced gait energy image and two-dimensional locality preserving projection
    LIN Chun-li WANG Ke-jun LI Yue
    2011, 31(03):  721-723.  DOI: 10.3724/SP.J.1087.2011.00721
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    In action classification, methods of feature extraction were either simple with low accuracy, or complicated with poor real-time quality. To resolve this problem, firstly, Enhanced Gait Energy Image (EGEI) was derived from Gait Energy Image (GEI); secondly, high dimensional feature space of the action was reduced to lower dimensional space by Two-Dimensional Locality Preserving Projection (2DLPP); then Nearest-Neighbor (NN) classifier was adopted to distinguish different actions. EGEI could extract more obvious feature information than GEI; 2DLPP outperformed principal component analysis and locality preserving projections in dimensional reduction. It was tested on the Weizmann human action dataset. The experimental results show that the proposed algorithm is simple, achieves higher classification accuracy, and the average recognition ratio reaches 91.22%.
    Image feature selection algorithm based on Q-relief
    2011, 31(03):  724-728.  DOI: 10.3724/SP.J.1087.2011.00724
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    Image feature selection is the significant part in pattern recognition, image understanding and so on. The relief algorithm has a blind deficiency in training feature weight. Q-relief was a new algorithm which was based on dividing instance set in self-adapting. Q-relief was proposed to solve the blind selection problem in the original relief algorithm. The presented algorithm was applied in Trouble of Moving Freight Car Detection System (TFDS). The classification results show that the Q-relief algorithm can improve the accuracy of recognition compared with other algorithms.
    License plate location based on quaternion specific color-pair edge detection
    WANG Jian LIU Li WANG Tian-hui
    2011, 31(03):  729-732.  DOI: 10.3724/SP.J.1087.2011.00729
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    License plate location plays an important role in the License Plate Recognition (LPR) system. A license plate location algorithm was presented, which was based on the quaternion specific color-pair edge detection technique. The original color image was first represented by using quaternion Same-Hue-Full-Saturation (SHFS) form. Then, four pairs of masks were used to detect specific color-pair edges. Next, mathematical morphology dilation operation was applied to extract potential license plate regions. Finally, several shape constraint conditions were employed to locate true license plate regions. The proposed method combined the color feature, edge feature and shape feature of license plates, and offered high robustness. The experimental results on 485 car images that are taken under various conditions show that the recall rate is 96.8% and the precision rate is more than 93.2%.
    Finite element approach driven by mutual information for medical image registration
    DANG Jian-wu SUN Teng WANG Yang-ping LI Sha DU Xiao-gang
    2011, 31(03):  733-735.  DOI: 10.3724/SP.J.1087.2011.00733
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    Discrete finite element was used as basic unit to simulate and predict deformation of the whole elastomer for complexity of soft tissue deformation in medical image. The process of registration was regarded as solving 2D stress problem by finite element method. The finite element energy function was also improved. Mutual Information (MI) with high accuracy and robustness was selected as metric for solving equation. In order to improve registration efficiency, registration process was optimized by the multi-resolution strategy. By registration experiment for medical images in radiotherapy and comparison with the existing methods, better registration results were obtained. The proposed registration method is more sensitive to the rigid displacement and with improvement in speed. All that shows this registration method is of high precision and efficiency.
    Person-independent facial expression recognition based on expression subspace multi-classifiers integration
    HU Bu-fa CHEN Bing-xing HUANG Yin-cheng
    2011, 31(03):  736-740.  DOI: 10.3724/SP.J.1087.2011.00736
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    To the problem that the average recognition rate of person-independent facial expression is not high (about 65%), a new method of facial expression recognition, based on expression subspace and multi-classifiers integration, was proposed. In the training set 1, the features of global face region, eyes (include eyebrows) region and mouth region were respectively extracted and decomposed by Local Binary Pattern (LBP) and Higher Order Singular Value Decomposition (HOSVD), and the corresponding expression subspaces were built. Then the facial images of the training set 2 were trained by Support Vector Machine (SVM) in the expression subspaces and the parameters of fuzzy rule system were conducted. Finally, the expression subspaces and the multi-classifiers ensemble were combined to classify the expressions in test set. The experiments were conducted on JAFFE database and the average recognition rate was 71.43%. The experimental results show that the proposed method effectively reduces the influence caused by facial shape feature and facial expression manner, and it has better recognition rate.
    Image matching method based on normalized grayscale variance Hausdorff distance
    GAO Jing SUN Ji-yin LIU Jing
    2011, 31(03):  741-744.  DOI: 10.3724/SP.J.1087.2011.00741
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    As for the large differences between the visual and infrared images in gray value caused by different imaging mechanism, inconsistent contour, the low matching probability of traditional matching methods based on gray or feature, the gray information of visual and infrared images was introduced after researching a variety of Hausdorfff Distance (HD) algorithms. Image matching method based on the neighbor grayscale information Hausdorfff distance was proposed. Based on the calculation of the similarity of edge feature points, the calculation of image normalized grayscale variance was added into this method, which effectively solved the low probability problem caused by different edge of visual/infrared image in Hausdorff distance matching algorithms. The simulation results of visual and infrared images matching show that under various conditions, compared with the conventional Hausdorff distance method, the proposed algorithm effectively improves matching effect under different light conditions and anti-jamming of noise.
    Hybrid image filter based on decimal object scale
    QIAN Xiao-liang GUO Lei YU Bo
    2011, 31(03):  745-748.  DOI: 10.3724/SP.J.1087.2011.00745
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    To remove the noise of optical images while preserving its fine details, the extant object scale was upgraded to the decimal object scale for reflecting the size of local object structure more accurately, and a hybrid image filter which contains two parts was proposed. The first part was an adaptive Gaussian filter based on decimal object scale, the scale of the Gaussian kernel and the mask size of filtering were controlled adaptively by the decimal object scale. The second part was an adaptive median filter based on decimal object scale, and the impulse noise points which were selected adaptively by the decimal object scale were filtered. The weakness of the first part in suppressing the impulse noise was remedied by the second part. Both theory analysis and simulation results show that the presented method can suppress various point-like noise and it is superior to several traditional methods in preserving the fine details and signal to noise ratio.
    Enhanced non-local means image denoising algorithm using structure detection
    XU Guang-yu TAN Jie-qing
    2011, 31(03):  749-752.  DOI: 10.3724/SP.J.1087.2011.00749
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    Concerning the problem of residual structure on Non-Local Means (NL-Means) image denoising algorithm, an improved NL-Means image denoising algorithm with structure detection was proposed. The noisy image was first processed by using a structure analyzer to extract detail information before filtering, then the similarity measure was modified to incorporate the result of edge detection, more weight was given to a pixel if its edge content was more similar to that of the pixel being denoised and the neighborhood with a dissimilar edge pattern should receive a lower weight (or zero) to preserve the original edge content. The experimental results show that the proposed algorithm enhances NL-Means denoising ability and image structural similarity, and improves the visual quality of the denoised image.
    New image denoising model based on fractional-order partial differential equation
    JIANG Wei
    2011, 31(03):  753-756.  DOI: 10.3724/SP.J.1087.2011.00753
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    Combining fractional order differential theory with total variation method, a new image denoising model was proposed, which was based on fractional Partial Differential Equation (PDE). Current Total Variation (TV) model was good at denoising and keeping the characteristics of image edge. This new model effectively inherited these advantages; at the same time, it used the fractional differential amplitude-frequency and retained texture details of smooth region effectively. The simulation results show that on one hand, compared with the existing denoising methods, the new model can not only suppress noise better, but also keep the characteristics of image edge better; especially, it is better than the existing integer order partial differential methods since it can retain more texture details. On the other hand, seen from the comparative experiments of PSNR, the model is more effective and practical on image denoising.
    New image denoising approach based on morphology
    HUANG Bao-gui MA Chun-mei LU Zhen-tai
    2011, 31(03):  757-759.  DOI: 10.3724/SP.J.1087.2011.00757
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    A new image denoising method based on Contour Bougie (CB) elements morphology was proposed. Considering the image characteristics on different scales, the morphological multi-scale algorithm based on contour structure elements was employed to remove the noise in image, and then the weighted fusion of the denoised image on different scales was done. A large number of experiments show that the proposed method can not only suppress many kinds of image noise but also protect the image detail effectively.
    Automatic vertebra segmentation based on graph cut and mean shift algorithm
    LIU Ji KANG Xiao-dong JIA Fu-cang
    2011, 31(03):  760-762.  DOI: 10.3724/SP.J.1087.2011.00760
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    To improve the efficiency of graph cut algorithm and reduce user interaction, the graph cut and mean shift algorithm were combined to automatically segment 3D vertebra images. The image was pre-processed with the mean shift method and the region graph was obtained instead of pixel graph, which could reduce dozen times edge numbers in the graph. Furthermore, the edge-preserving property of mean shift algorithm was used. The experimental results show that the proposed method possesses nice properties of the mean shift and graph algorithm, so it is efficient and accurate, and it also reduces user interaction.
    Gravitational approach to edge detection based on nonlinear filtering
    ZHANG ChunXue CHEN Xiu-hong
    2011, 31(03):  763-766.  DOI: 10.3724/SP.J.1087.2011.00763
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    Introducing the nonlinear filtering operator into the gravitational edge detection algorithm, a new edge detection method was presented. Firstly, the image was used to calculate the nonlinear gradient value of every pixel. Then a normalized function was constructed by using the nonlinear gradient value as independent variable. Finally, the gravitational edge detection was implemented by using the function value instead of the gray value of center pixel. The experimental results demonstrate that, compared with traditional edge detection algorithms, the proposed approach has better accuracy in edge location and get favorable edge for various noise images.
    Information security
    Risk assessment model for trusted platform control module based on Bayesian network
    WANG Dan ZHOU Tao WU Yi ZHAO Wen-bing
    2011, 31(03):  767-770.  DOI: 10.3724/SP.J.1087.2011.00767
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    A risk assessment model based on Bayesian network was proposed. In this model, each risk event influencing the Trusted Platform Control Module (TPCM)'s trust was analyzed. According to the relation among risks, the Bayesian network evaluation model was built. According to the evaluation from expert, Bayesian network inferring method was used to evaluate the risk probability and its influence. The whole system's risk value and risk priority were determined. An example was given to verify the model's correctness and validation.
    Contourlet domain image encryption based on chaos mapping
    GU Guo-sheng LIU Fu-chun
    2011, 31(03):  771-773.  DOI: 10.3724/SP.J.1087.2011.00771
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    Concerning the security of the Contourlet-based set partitioning in hierarchical trees compression method, a new image encryption algorithm based on chaos mapping was proposed. The presented algorithm contained two steps: ranked tables permutation using chaotic scrambling arrays; bit streams XOR processing using chaotic binary streams. The simulation results indicate that the cipher image satisfies requests for content masking. It also demonstrates that the proposed algorithm is sensitive to the initial values and has fast speed and high security.
    IP traceback based on router interface
    ZHANG Hai-cong WANG Xiao-ming
    2011, 31(03):  774-777.  DOI: 10.3724/SP.J.1087.2011.00774
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    IP traceback is an important way to defend against distributed denial of service attack. Gong et al's IP traceback method was analyzed and the disadvantage of low speed in reconstructing path was pointed out. An improved scheme was proposed to overcome the disadvantage. The presented scheme employed the information of router interface to mark a route so as to shorten the mark length in original method. In the proposed scheme, the speed of reconstructing path was enhanced and the false positive was lowered since it was decided whether the log was detected according to the deployment of router. Moreover, the scheme can well support incremental deployment.
    Access control model of workflow permission based on group and role
    YU Chun-sheng NIE Jing
    2011, 31(03):  778-780.  DOI: 10.3724/SP.J.1087.2011.00778
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    Role-based Access Control (RBAC) has been widely used as an international norm, but it can only give users authority to operate a particular operating environment issues, and it cannot be used to solve the access control problems of different subsets of operating objects under same conditions. Especially in the workflow system, access control of different set of objects, and different nodes is particularly important. To address this problem, role-based access control technique and workflow technique were studied. An access control model of workflow permissions was proposed based on group/role, which achieved two-dimensional operation set access control permissions. It is a better solution to the cross-regional case, the multi-sector work-based workflow system object access control and access control problems. Currently, the model has been used in the construction of oilfield integration system, and the application shows that the model is scientific, reasonable and feasible.
    Trust-based authentication routing protocol for satellite network
    PAN Yan-hui WANG Tao WU Yang WANG Wen-hao
    2011, 31(03):  781-783.  DOI: 10.3724/SP.J.1087.2011.00781
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    Security routing protocol is a key element to guarantee satellite network security. To solve the problem that most of routing protocols lack security scheme, the Elliptic Curve Pintsov-Vanstone Signature Scheme (ECPVSS) was used to attain confidentiality and authentication of packets, and trust evaluation scheme could exclude internal malicious node from the route path. Then a security routing protocol oriented to High Altitude Platform (HAP)/Low Earth Orbit (LEO) architecture was formed. The analysis results show that the proposed protocol can prevent network from some common routing attacks.
    Network attack-defense strategy based on rough Bayesian game
    WANG Chun-zi HUANG Guang-qiu
    2011, 31(03):  784-789.  DOI: 10.3724/SP.J.1087.2011.00784
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    To solve the problem in attack-defense strategy research of complex network, an analysis method based on rough Bayesian game was proposed. By introducing rough set theory into object Petri net, the authors defined Attack-Defense Confrontation Model (A-DCM), which divided domain strategy set into equivalence class and accordingly put forward the characteristic strategy set. Rough Attack-Defense Game Model (RA-DGM) and utility function were presented, and the Bayesian equilibrium solution algorithm was given, so that the maximal attack-defense strategy set could be acquired. The analysis method was suitable for attack and defense research of complex network, which could reduce strategy space scale effectively. The experimental results verify the correctness and performance of the model, and demonstrate that the attack-defense strategy analysis method based on the model is more reasonable and effective.
    New short group signature scheme without random oracles
    YUAN Yan CAI Guang-xing
    2011, 31(03):  790-792.  DOI: 10.3724/SP.J.1087.2011.00790
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    On the basis of BBS short group signature scheme, a new short group signature scheme based on the Strong Diffie-Hellman (SDH) assumptions and the decision linear assumption was constructed. The scheme was verified to satisfy the security demand of full anonymity and full traceability. Compared with the latest schemes security in the standard model, this scheme has shorter length of group signature and higher operation efficiency, and it allows new members to join in the group.
    Security analysis of "zero rekeying" scheme based on multi-cast RSA
    JIKE Lin-hao YANG Jun
    2011, 31(03):  793-797.  DOI: 10.3724/SP.J.1087.2011.00793
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    Recently, Lin, Tang and Wang proposed a multi-prime RSA based on a star architecture of key distribution and made use of it to construct a centralized group key management scheme. According to several main security requirements of group key management, from the perspective of cryptographic engineering practice and applying computational number theory, four kinds of attacks against this scheme were proposed: a ring idempotent attack, a chosen plaintext attack,an attack of extracting high order integer roots, and a collusion attack based on the elliptic curve factoring method and Chinese remainder theorem. The mathematical analysis and cryptanalysis indicate that under certain conditions these attacks can be realized efficiently, and it is the characteristic of "without rekeying the key server's encryption exponent" that causes such security risks.
    Security proof of Molnar protocol
    DENG Qiang-dong WANG Li-bin
    2011, 31(03):  798-800.  DOI: 10.3724/SP.J.1087.2011.00798
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    Molnar protocol is a scheme for mutual authentication between tags and readers in Radio Frequency Identification (RFID) system, which emphasizes protecting privacy for the tag; however, its security has not been proved formally. By using the eHa model, a formal proof was given, in which the output of the Molnar protocol maintain unpredictable, denoted as un-privacy. Moreover, the accurate security boundary of the Molnar protocol was computed. The privacy of protocol was reduced tightly on the assumption that the output of pseudorandom functions was indistinguishable from the output of random functions in polynomial time by utilizing the game-based technique. This technique is a powerful tool for analyzing and solving the privacy problem of RFID system, and provides an effective and universal solution.
    Forward-secure unidirectional threshold proxy re-signature
    YANG Xiao-dong WANG Cai-fen
    2011, 31(03):  801-804.  DOI: 10.3724/SP.J.1087.2011.00801
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    To reduce the loss caused by the leakage of the re-signature key, a scheme of forward-secure unidirectional threshold proxy re-signature (FSTPRS) was proposed in this paper. The re-signature key was updated in each period by one-way function while the public key remains fixed. As a result, even if the current re-signature key was exposed, the adversary could not recover the re-signature key before the current time period or forge any signatures pertaining to the past. The security of scheme was proved in the standard model. The analysis result shows that it is robust and secure against the existing forgery under the adaptive chosen message attack, under the condition of the computational Diffie-Hellman.
    RFID authentication protocol based on Hash function and key array
    XIE Chuan
    2011, 31(03):  805-807. 
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    Wireless transmission, broadcast of signals, resource-constraint disturb the reliability of Radio Frequency Identification (RFID) system and block the deployment progress of RFID techniques. Through the analysis of current common RFID authentication protocol, an authentication protocol based on Hash function and key array was proposed. The new protocol used one-way Hash function value instead of label identifier, and designed independent authentication key for each pair between the reader and the tag in the certification process. It could resist several possible attacks, including eavesdropping, location tracking, re-transmission attacks, Denial of Service (DoS), tampering and other attacks. It has obvious advantages in enhancing the tag identity privacy, and resisting the threat from within the system.
    XML digital signature application in workflow system
    FU De-sheng WANG Qiang
    2011, 31(03):  808-811.  DOI: 10.3724/SP.J.1087.2011.00808
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    In view of the demand for multi-signature and fine-grained signature in workflow systems, the authors proposed the "Signature on Signature" mechanism and put forward an application model of eXtensible Markup Language (XML) signature in workflow systems. In this model, the document to be signed was converted to XML format, and this facilitated the handling of the document for the system. In the processing of the XML document, every processing node signed and verified on the basis of the former processing node. In the end, a purchase approval workflow system was developed. Taking a typical purchase approval scenario for example, the validity and effectiveness of the presented model were verified, and a feasible solution was provided for the application of XML digital signature in workflow systems.
    Typical applications
    Working diagram algorithm of maglev train
    ZHANG Qi-liang CHEN Yong-sheng
    2011, 31(03):  812-814.  DOI: 10.3724/SP.J.1087.2011.00812
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    The paper analyzed the difference of operation control system between railway train and maglev train. Based on the construction of the train working diagram of railways, the restriction model and algorithm of maglev train working diagram were put forward. The paper used the "station-time" matrix to check the train operation conflict and applied the iterative repair method to remove the conflicts; at last, the system got the feasible train working diagram. The computational example indicates that the proposed algorithm is able to work out the working diagram schemes of maglev effectively, and it has higher effectiveness and practicability.
    Optimal threshold price for name-your-own-price retailer with limited marketing period
    ZHOU Zhen-hong
    2011, 31(03):  815-817.  DOI: 10.3724/SP.J.1087.2011.00815
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    Name-Your-Own-Price (NYOP), a new sales mode, has emerged in recent years and is different from traditional pricing mode. To solve the problem of optimal pricing strategy of a name-your-own-price retailer when marketing period is limited and the retailers' inventory is limited, the online retailers' maximum expected revenue model was put forward based on optimization method. The relationship between the optimal threshold price and limited inventory and the selling time were obtained by numerical analysis of the model. The conclusion shows that the retailer should set the optimal threshold price based on sales period and inventory.
    Design and implementation of open user model service platform
    WANG Qiao-rong CHEN Qing-kui ZHAO Hai-yan
    2011, 31(03):  818-821.  DOI: 10.3724/SP.J.1087.2011.00818
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    To build a common user model platform which can share data and provide more comprehensive and accurate user information to all sites accessed to the platform, the platform provided data interfaces and algorithm interfaces to interact with the third-party sites, focused on how to solve the conflict of user data from different data sources in order to form a unified user model, finally achieved sharing of algorithms, models and data. The experimental results show that it is more accurate and comprehensive to build user model on this platform.
    Power-related hardware/software partitioning based on Hopfield neural network and tabu search
    LI Ran GUO Bing SHEN Yan WANG Ji-he WU Yuan-sheng LIU Yun-ben
    2011, 31(03):  822-825.  DOI: 10.3724/SP.J.1087.2011.00822
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    Nowadays, as low carbon economy has been advocated worldwide, the power consumption of embedded software has become a critical factor in embedded system design. The hardware/software partitioning is an important method of embedded software power optimization. Firstly, this paper constructed a hardware/software bi-partitioning model with the goal of embedded software power consumption under the constraints of performance; then, a hybrid algorithm was proposed based on the fusion of discrete Hopfield Neural Network (HNN) and Tabu Search (TS), in which HNN as the main method could quickly obtain a feasible solution of partitioning, and the TS algorithm could "taboo" the current solution and transferred to the other minimum points that could jump out from the local optimal solution. Lastly, the experimental results show that the proposed algorithm posses better time performance and higher probability of acquiring the global optimal solution in contrast with other similar algorithms.
    Evolution of software product family component and its complexity evaluation
    ZHANG Yuan-ming XIAO Gang XU Gong-xu LU Jia-wei
    2011, 31(03):  826-830.  DOI: 10.3724/SP.J.1087.2011.00826
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    Evolving new software component based on previous software components is a key technique to improve software reusability and satisfy users' various demands. In this paper, an interactive evolution model was proposed based on multiple Agents, which could autonomously process consistent data. Then, the aspect weaving mechanism, which can effectively reduce the coupling degree of different function areas, was introduced in evolution to insert new codes into the exact places of target component. Furthermore, the evolution complexity was also discussed and several indicators and a model were given to calculate evolution cost. Finally, a data exchange component used in digital campus system was given to illustrate the effectiveness of above evolution methods.
    Design principle of Java-In-A-Box and its application to common fundamental module in point of sale
    LI Gui-lin ZHANG Wei-da
    2011, 31(03):  831-833.  DOI: 10.3724/SP.J.1087.2011.00831
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    A design method named Java-In-A-Box (JIAB) was proposed to make the Android suitable for developing large scale programs. By re-encapsulating the inner components of Android platform, the responsibility boundaries among user interface, business logic and data storage were clear. Based on JIAB, the common fundamental module for an embedded Point of Sale (POS) was designed and implemented. It has been found that the JIAB method is suitable for developing large scale applications on Android platform.
    RB-CRSP: Node role-based computing resources sharing platform over Internet
    ZHANG Xue-feng XU Sheng-chao
    2011, 31(03):  834-838.  DOI: 10.3724/SP.J.1087.2011.00834
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    A role-based computation resource sharing platform called RB-CRSP was proposed in this paper. The node roles and functions were strongly considered in design toplogy of RB-CRSP. All the nodes in RB-CRSP were assigned as server, coordinator, worker, and client. By using the united programming model, it could be in harness with the immense computational resource available in the Internet for parallel and distributed computation efficiently. RB-CRSP platform was also load balancing and fault-tolerant, which was strongly supported by hardware and credit standing based scheduling algorithm and the workers oriented fault tolerance policy. In order to demonstrate the effectiveness of RB-CRSP, a serial of simulation experiments were done. The results obtained from performance analysis show that RB-CRSP is feasible and efficient which can provide a new way for computing resource sharing over the Internet. The hardware conditions and availability of machines are important factors in this test.
    Fractal computing parallelization and implementation in TBB
    CHEN Rong-xin CHEN Wei-bin LIAO Hu-sheng
    2011, 31(03):  839-842.  DOI: 10.3724/SP.J.1087.2011.00839
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    The template-based feature in Threading Building Blocks (TBB) simplifies parallel design and is suitable for efficient design of multi-core parallelism. Since fractal computing is CPU-intensive, it is practicable to parallelize fractal computation under TBB. As to the workload unbalance problem in parallelism, a balance method based on sampling execution time was presented to estimate workload. The proposed method realized the task partition through the workload estimate from sampling execution time, and TBB task scheduler was invoked for parallel process. The experimental results show that the proposed method has high estimation accuracy and low time rate so as to effectively achieve workload balance, and good speedups are available through TBB design.
    Accelerated molecular dynamics simulation using multi-core CPU and GPU
    LIN Jiang-hong LIN Jin-xian LV Tun
    2011, 31(03):  843-847.  DOI: 10.3724/SP.J.1087.2011.00843
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    On the heterogeneous architecture of multi-core Central Processing Unit (CPU) and Graphic Processing Unit (GPU), the Open Multi-Processing (OpenMP) and the programming interfaces of Compute Unified Device Architecture (CUDA) were used to implement a molecular dynamics simulation program based on AMBER force field. In order to efficiently use computer processing power, the program was divided into different parts which were processed by CPU single-thread, CPU multi-thread and GPU multi-thread respectively. The experimental results show that compared with the optimized CPU-based implementations, the heterogeneous parallel computing model based on multi-core CPU-GPU gets powerful performance advantage. Especially, the calculations of forces, which account for more than 90% of processing time, get at most 12 times faster than CPU-based implementations while being implemented on GPU.
    Groundwater quality evaluation based on optimized model of decision-tree-based support vector machine
    CHEN Hai-yang TENG Yan-guo WANG Jin-sheng
    2011, 31(03):  848-850.  DOI: 10.3724/SP.J.1087.2011.00848
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    Support Vector Machine (SVM) based on the minimum of structured risk is characterized with strong ability to learn and predict and favorable classification performance, which makes it able to solve the two types of pattern recognition of fewer sample learning. In order to evaluate the groundwater quality which has five classes with SVM, the decision-tree-based way of rebuilding the classes like decision tree to create more sub two-class SVM would be used. But as a solution of classifying more classes, some defaults exist in decision-tree-based support vector machine (DTBSVM) including the local error produced by different sample mount between two classes. The authors brought forward an optimized DTBSVM model based on the principle of two cross tree to realize the evaluation for groundwater quality. The experimental results show that the optimized DTBSVM model is a good way to evaluate the groundwater quality.
    Implementation of LU decomposition and Laplace algorithms on GPU
    CHEN Ying LIN Jin-xian LV Tun
    2011, 31(03):  851-855.  DOI: 10.3724/SP.J.1087.2011.00851
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    With the advancement of Graphics Processing Unit (GPU) and the creation of its new feature of programmability, many algorithms have been successfully transferred to GPU. LU decomposition and Laplace algorithms are the core in scientific computation, but computation is usually too large; therefore, a speedup method was proposed. The implementation was based on Nvidia's GPU which supported Compute Unified Device Architecture (CUDA). Dividing tasks on CPU and GPU, using shared memory on GPU to increase the speed of data access, eliminating the branch in GPU program and stripping the matrix were used to speed up the algorithms. The experimental results show that with the size of matrix increasing, the algorithm based on GPU has a good speedup compared with the algorithm based on CPU.
    Ultrasound color flow imaging based on compute unified device architecture
    FAN Zheng-juan TAN Chao-wei Dong C. LIU
    2011, 31(03):  856-859.  DOI: 10.3724/SP.J.1087.2011.00856
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    Ultrasound Color Flow Imaging (CFI) is widely used in clinical diagnosis. This paper made two improvements for previous research about Graphics Processing Unit (GPU) framework for CFI: on wall filtering block, the parallel regression filtering was implemented instead of Finite Impulse Response (FIR) filter; on post-processing block, the parallel threshold box filtering was added to improve flow uniformity. The experimental data were acquired from a healthy carotid artery: 88 scan lines, 510 samples along the scan line, and an ensemble size of 16. The experimental results show that, compared with the serial algorithm based on Central Processing Unit (CPU), the computational efficiency of the proposed parallel algorithms based on GPU has been increased by 15.2 times and the frame rate increases up to 70. The color flow image can achieve a high quality by the regression filter instead of FIR filter, and improve the accuracy of tissue/flow detection by threshold box filter.
    Application of improved cerebella model articulation controller in forest fire recognition
    WANG Hua-qiu LIU Ke
    2011, 31(03):  860-864.  DOI: 10.3724/SP.J.1087.2011.00860
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    Concerning the defects of traditional fire recognition, a forest fire recognition system of Cerebella Model Articulation Controller (CMAC) network, which was based on variable step Least Mean Square (LMS) algorithm of hyperbolic secant, was presented. Through analyzing some initial static and dynamic characteristics, forest fire was preliminarily identified. And on the basis of image segmentation using the optimal threshold search method, the corresponding eigenvectors were extracted as the input of the improved CMAC network to detect and identify forest fire. The simulation results show that the improved method can accurately and efficiently identify flame.
    Optimal design and implementation ofcalendar shopping system based on Memcached
    XUE Xian-peng PENG Ming-tian HE Huai-qing
    2011, 31(03):  865-868.  DOI: 10.3724/SP.J.1087.2011.00865
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    Concerning the problem of large computation, slow response and repeated computation in travel sky-based Calendar Shopping (CS) system, an efficient method was proposed to cache calculation results of unit in this paper. The system architecture was redesigned and the performance of calendar shopping system was optimized. The experimental results show that the presented method can reduce the system response time and improve the performance of the system significantly, also it provides the method and theoretical support for calendar shopping system in civil aviation field.
2024 Vol.44 No.3

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