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Table of Content

    01 June 2011, Volume 31 Issue 06
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    Network and communications
    Algorithm optimization of MPI collective communications in KD60
    ZHENG Qi-long WANG Rui ZHOU Huan
    2011, 31(06):  1453-1457.  DOI: 10.3724/SP.J.1087.2011.01453
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    Large clusters have been developed to multicore era, and multicore architecture makes new demands on parallel computation. Message Passing Interface (MPI） is the most commonly used parallel programming model, and collective communications is an important part of the MPI standard. Efficient collective communications algorithm plays a vital role in improving the performance of parallel computation. This paper first analyzed the architecture features of KD60 and communication hierarchy characteristics under multicore architecture, and then introduced the implementation of collective communications algorithm in MPICH2 and pointed out its deficiencies. At last, this article took broadcasting as an example, using an improved algorithm based on CMP architecture，which changes the communication mode of the original algorithm. At the same time, this paper optimized the algorithm according to the architecture characteristics of KD60. The experimental results show that the improved algorithm improves the performance of broadcast in MPI.
    Priority-based service differentiation and rate control strategy
    LIU Hong-tao CHENG Liang-lun
    2011, 31(06):  1458-1460.  DOI: 10.3724/SP.J.1087.2011.01458
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    To support Quality of Service (QoS) requirements for different kinds of network in medium and high rate wireless sensor networks, a priority-based service differentiation and rate control strategy was proposed. The strategy gives high priority to the traffic with strong real-time and reliability requirement for service differentiation, calculates the rate difference using the factor ε, and adjusts the sending rate of its upstream node by using hop-by-hop method. The simulation results show the proposed strategy can guarantee high-priority real-time traffic with high throughput and low latency, and maintain the stability of the network throughput.
    New Q-learning based heterogeneous network selection algorithm
    ZHAO Yan-qing ZHU Qi
    2011, 31(06):  1461-1464.  DOI: 10.3724/SP.J.1087.2011.01461
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    To meet the diverse service requirements in heterogeneous network and adapt to the dynamic changes in the network environment, choose the most suitable network for every session and realize network load balance, a new algorithm based on Q-learning for the selection of wireless access network in the heterogeneous network composed of HSDPA and WiMax was proposed. By this algorithm, the most suitable network for each session can be selected according to network load conditions, service attribute, mobility and different locations of terminal. At last, the simulation results show that the algorithm can lower system blocking probability, increase spectrum utility and realize the autonomy of network selection.
    Group clustering protocol based on energy balance for wireless sensor networks
    DENG Yaping CHEN Zheng
    2011, 31(06):  1465-1468.  DOI: 10.3724/SP.J.1087.2011.01465
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    Concerning the inequality of cluster-head distribution and node energy consumption in Wireless Sensor Network (WSN) cluster routing protocol, a node-energy load-balance clustering algorithm was proposed. Group according to the node energy, dynamically adjust the group number to the node energy reduction, conduct cluster-head election in the group according to the energy focus, and further balance the node energy consumption using cluster-head rotate and multi-hop routing between clusters. The simulation results show that this protocol effectively balances the energy consumption among network nodes and achieves an obvious improvement in network stable period.
    Optimization of macro-handover in hierarchical mobile IPv6
    LI Xiangli SUN Xiaolin GAO Yanhong WANG Weifeng LIU Dawei
    2011, 31(06):  1469-1471.  DOI: 10.3724/SP.J.1087.2011.01469
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    The macro handover has caused high packet loss and long handover latency in Hierarchical Mobile IPv6 (HMIPv6) protocol. To solve these problems, this paper proposed a protocol named Tunnel-based Fast Macro-Handover (TBFMH), which introduced the mechanism of tunnel, acquired care-of addresses on the grounds of handover information, conducted duplication address detection in advance and completed local binding update while building the tunnels. The simulation results show that TBFMH can decrease the handover latency by 50% at least and reduce the packet loss rate compared to HMIPv6, which effectively improves the performance in the macro handover.
    TCP congestion avoidance algorithm based on adaptive congestion window
    LIU Jun
    2011, 31(06):  1472-1475.  DOI: 10.3724/SP.J.1087.2011.01472
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    Concerning the unsmooth growth of congestion window at congestion avoidance phase of TCP Reno, the traditional AIMD algorithm was researched and an improved congestion avoidance algorithm was proposed: a logarithmic function based on the growth of congestion window was adopted. In this new algorithm, additive factor is usually increased quickly when the network is doing well and less so when network situation is getting to congestion. The mathematical analysis shows the feasibility of the new algorithm, and its throughput, fairness and friendliness were evaluated by NS simulation. The simulation results show the effectiveness of the algorithm.
    Residual analysis and correction in IEEE 1588v2 standard based on transparent clock
    ZHANG Heming YANG Bin
    2011, 31(06):  1476-1479.  DOI: 10.3724/SP.J.1087.2011.01476
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    In order to reduce accumulation errors in the time synchronization for higher required systems, in this paper, the source of residual in clock synchronization and the working principle of transparent clock were in-depth analyzed. Combined with the delay request-response mechanism and the peer delay mechanism of IEEE 1588v2, a precise clock synchronization protocol applied to networked measurement and control systems, a set of high precision simultaneous algorithm based on transparent clock was summarized in detail. According to the test results, synchronization accuracy and precision in the sub-microsecond range can be perfectly reached by drift adjustment and offset adjustment, which can fully comply with the required precision requirments.
    Agent-based cooperative spectrum sensing algorithm
    YE Qingsong HUI Xiaowei
    2011, 31(06):  1480-1482.  DOI: 10.3724/SP.J.1087.2011.01480
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    To improve the spectrum sensing performance of cognitive radio technology, in this paper, a new Agent-based cooperative spectrum sensing algorithm was proposed. This algorithm used multiple local energy detection threshold in the local detection, while the Signal-to-Noise Ratio (SNR) estimated by the cognitive user was sent to the main control center of Agent, then the control center based on SNR and the distance between the transmitter and cognitive nodes to balance, to select the cognitive nodes with high reliability and validity of to decision fusion. The simulation results show that the algorithm can improve the cooperative spectrum sensing capabilities of cognitive radio networks, and at the same time reduce the number of nodes involved in the original perception of cooperative sensing algorithm to some extent.
    Computer software technology
    Unexpected behaviors detection in embedded system based on instruction stream
    SU Yong-xin DUAN Bin
    2011, 31(06):  1483-1486.  DOI: 10.3724/SP.J.1087.2011.01483
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    Most traditional embedded system security detection methods cannot meet all of the requirements of fast detection, independent detection and without interference to application program. Thus, the authors have developed a method of unexpected behaviors detection for embedded system to meet those requirements. The proposed detection system is independent and operates parallel to an embedded processor. And, the logic of the proposed detection is to compare the instruction stream from embedded processor with the instruction expected by source binary, thus detecting any unexpected behaviors caused by deviating from its original program. Moreover, the detection logic presents common suitability of adapting different repertoires. Then experimental results show that this method has the ability of detecting minimum granularity unexpected behavior by checking out random bit flips, and with average detection latency of 6 cycles if taking no account of the instructions for interrupt-site protection.
    Method of semantic similarity calculation for component testing ontology
    HAN Xian-yu JIANG Ying
    2011, 31(06):  1487-1490.  DOI: 10.3724/SP.J.1087.2011.01487
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    Concerning the problem that some results are easily leaked while the component testing ontology is retrieved using the existed calculation method of ontology semantic similarity, a similarity calculation method based on concept and attribute was proposed to improve the retrieval efficiency of component testing information. Firstly, the structure, hierarchy, the number of offspring nodes and ancestor nodes of concept were used to calculate the concept similarity. Then, the attribute similarity was calculated based on the concept similarity of the attributes and its data type similarity. Finally, the concept similarity and attribute similarity were combined to calculate the comprehensive ontology semantic similarity. The experimental results indicate that the similarity calculation method can be applied in component testing and other domains effectively.
    Transformation of OWL-S model to rewrite-logic model
    SHEN Ya-fen HUANG Ning PENG Yong-yi
    2011, 31(06):  1491-1494.  DOI: 10.3724/SP.J.1087.2011.01491
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    Web Ontology Language for Services (OWL-S) model, based on service, plays an important role in software design but it cannot be formally analyzed and verified directly because of its non-fully formalized model. The automatic conversion tool from OWL-S model to rewrite-logic model, which was based on semantic framework of rewrite logic and converted by data types, expressions, control structures and process, was designed and completed. It can formally analyze and verify the design model before software implementation and provide the basis for reliability analysis.
    Importance decision analysis on software testing design
    WANG Qiang JI Xiao-qing
    2011, 31(06):  1495-1497.  DOI: 10.3724/SP.J.1087.2011.01495
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    A testing design decision analysis algorithm based on test importance was proposed for software test design strategy optimization. According to Analytic Hierarchy Process (AHP) theory, the algorithm was used to solve the problem of test importance comparison and analysis through combining quantitative and qualitative methods. Then the targets including optimization of test design strategies, reasonable distribution of test resources, effectively finding software defects can be achieved.
    Solution of removable storage control based on file system filter driver
    CAO Cheng-long FU De-sheng CAO Feng-yan
    2011, 31(06):  1498-1501.  DOI: 10.3724/SP.J.1087.2011.01498
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    Concerning the access control security for removable storage, an access control method for removable storage based on File System (FS) filter driver was proposed. This method identified more than one removable storage device volumes and unique identifier for each volume, and controlled the volume according to its access. Additionally, through monitoring the process execution, this method prevented and killed Trojan. Using this method, the current popular removable storage devices were controlled to achieve a better result, enhancing the safety of using removable storage devices.
    Information security
    Self-adaptive image encryption algorithm based on chaotic map
    DENG Shaojiang HUANG Guichao CHEN Zhijian XIAO Xiao
    2011, 31(06):  1502-1504.  DOI: 10.3724/SP.J.1087.2011.01502
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    This paper presented a new self-adaptive image encryption algorithm so as to improve its robustness. Under this algorithm, a gray image or color image was divided into 2×2 size blocks. A corresponding size of matrix in the top right corner was created by the pixel gray-scale value of the top left corner under Chebyshev mapping. The gray-scale value of the top right corner block was then replaced by the matrix created before. The remaining blocks were encrypted in the same manner in clockwise until the top left corner block was finally encrypted. This algorithm is not restricted to the size of image and it is suitable to gray images and color images, which leads to better robustness. Meanwhile, the introduction of gray-scale value diffusion system equips this algorithm with powerful function of diffusion and disturbance.
    Image watermarking algorithm based on artificial neural networks classification
    SHAO Xiaogen SUN Tiankai DING Bin WANG Xingyuan
    2011, 31(06):  1505-1507.  DOI: 10.3724/SP.J.1087.2011.01505
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    The paper, by adopting jointly Artificial Neural Network （ANN）, general Amold mapping, and statistical methods, intends to formulate an algorithm based on image spatial domain watermark. While the ANN was used as the texture analyzer of the original image, the texture zone of the original image would be given prominently. The safety of the watermark was improved by using the amold mapping rearrangement. An optimizing strategy of minimizing the changes of pixels was adopted when the watermark is embedded. The application of statistical method guaranteed the sightlessness and the robustness of the digital watermark information. The experimental results demonstrate that the watermark is robust against cut attack, salt-pepper noise attack, Least Significant Bit (LSB) attack, winner attack, and so on.
    Video watermarking algorithm based on compressive sensing
    ZHOU Yan ZENG Fanzhi
    2011, 31(06):  1508-1511.  DOI: 10.3724/SP.J.1087.2011.01508
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    For the problem of integrity authentication about compressed video streams, this paper proposed a video watermarking algorithm based on Compressive Sensing (CS). The H.264 compressed video stream was taken as the research object. By conducting random projection on the I frames of video sequences, a slight amount of measurements were obtained. Through quantization and replacement encryption, the measurements were embedded into the macro block which had the maximum amplitude in the motion vector in P frame. While authenticating, the watermark was extracted from the P frame that contains watermarked video sequences, and the similarly random CS projection on the I frames was conducted. By comparing the difference between the measurements, the integrity of video could be authenticated. The simulation results show that the intended video watermarking algorithm ensures high video quality, and little effect on the encoding rate, and it has strong robustness against attacks such as frame deletion and frame insertion.
    Signature scheme for securing two-source network coding against pollution attacks
    NIU Shufen WANG Caifen LIU Xueyan
    2011, 31(06):  1512-1514.  DOI: 10.3724/SP.J.1087.2011.01512
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    Networks coding is highly susceptible to pollution attacks，but such attacks cannot be prevented by the standard technology of signature. Based on the vector hash which is secure if the discrete logarithm problem is infeasible，an efficient signature scheme for securing two-source networks coding against pollution attacks was proposed. In this scheme, each source node signed the files with its own private key, the intermediate nodes, with the merge algorithm, produced linear combinations of vectors from different files. The intermediate nodes could verify the received signature solely by the public key. The security of signature scheme relies on the hardness of the Co-Deffie-Hellman problem. Under the random oracle model, the new scheme is proved to be secure against the source nodes and intermediate nodes attacks.
    Research of Web Services attack detection based on ontology
    CHEN Jun WU Lifa XU Guanghui HE Zhengqiu HUNAG Kangyu
    2011, 31(06):  1515-1520.  DOI: 10.3724/SP.J.1087.2011.01515
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    Web service greatly facilitates the application-to-application integration based on heterogeneous platform, but its core components are faced with threats of malicious attacks. Currently, the Intrusion Detection System (IDS) is usually used to prevent these attacks. However, the IDSs distributed throughout the network may be developed by different vendors and there is not a common vocabulary understandable among them. Therefore, the IDSs stopped people from cooperatively preventing the multi-phased and distributed attacks easily. In this paper, a new method based on ontology and OWL to classify and describe the Web services attack was presented. Through constructing a Web services attack ontology, the common understandable vocabulary could be provided for different IDSs. Then, an intrusion detection system based on the Web Service Attack ontology (called O-IDS) was presented as well, which could efficiently overcome the shortage of the existed IDS and enhance the ability to detect the multi-phased and distributed attacks.
    DDoS detection with non-iterative Apriori algorithm
    Yan GAO WANG Taihua GUO Fan YU Min
    2011, 31(06):  1521-1524.  DOI: 10.3724/SP.J.1087.2011.01521
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    An improved non-iterative Apriori algorithm was proposed to detect Distributed Denail of Service (DDoS) attacks. An one-step intersection operation was used to process network packets within the specific time range, and the strong correlation rules of the packets were studied so as to achieve the quick detection of DDoS atttacks. In comparison with current algorithms, it shows better performance in efficiency and storage space in detection of DDoS attacks. Experimental results on DARPA data-sets show the algorithm is able to detect DDoS effectively.
    Error-tolerant searchable data sharing scheme
    YI Lei ZHONG Hong YUAN Xianping ZHAO Yu
    2011, 31(06):  1525-1527.  DOI: 10.3724/SP.J.1087.2011.01525
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    A new data sharing scheme was proposed to solve the problem of error-tolerant search and fine-grained access control. This new scheme adopted the technology of locality-sensitive hashing and the predicate encryption, which allowed users to search for keywords in an error-tolerant manner, and modified the users access rights easily by updating the encrypted data. The computational complexity of updating is more optimized than the existing scheme. The theoretical analysis shows that the proposed solution is correct, safe and effective.
    New image encryption algorithm based on cellular neural network
    REN Xiaoxia LIAO Xiaofeng XIONG Yonghong
    2011, 31(06):  1528-1530.  DOI: 10.3724/SP.J.1087.2011.01528
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    In this paper, a new image encryption algorithm was presented by employing Cellular Neural Network (CNN). The main objective was to solve the problem of traditional stream ciphers insensitivity to the change of plain text. By using a hyper chaotic system of 6-D CNN as the key source, selecting the secret key based on the results of logical operations of pixel values in the plain image, and introducing simultaneously both position permutation and value transformation, the new algorithm was presented. It is shown that both NPCR value and the sensitivity to key (>0.996) can meet the security requirements of image encryption. The simulation process also indicates that the algorithm is relatively easy to realize with low computation complexity, and ensures, accordingly, the secure transmission of digital images.
    Defense system model based on trust for cloud computing
    ZHOU Qian YU Jiong
    2011, 31(06):  1531-1535.  DOI: 10.3724/SP.J.1087.2011.01531
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    Because of the cloud computings characteristics of being dynamic and open, continuous malicious attacks happen frequently. With the idea of trusted cloud, a defense system model based on trust for cloud computing was constructed to guarantee the cloud security. Through real-time monitoring, users behavior evidences could be obtained and standardized; a new method for users trust evaluation based on fuzzy Analytic Hierarchy Process (AHP) was presented, which gradually determined the weights of behavior evidences, achieved quantitative assessment of behavioral trust; so as to provide great security defense for users. Besides, multiple detection engines were used to conduct a comprehensive inspection of suspicious files and to make integrated decisions. The experimental results show the system model can effectively eliminate the malicious behaviors from undesirable users, reduce users damages caused by virus and achieve a two-way defense for both cloud and client.
    Security analysis and improvement of a certificateless signature scheme
    HUANG Mingjun DU Weizhang
    2011, 31(06):  1536-1538.  DOI: 10.3724/SP.J.1087.2011.01536
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    Nowadays, many centificateless signature schemes depend on the honesty of Key Generation Center (KGC) excessively, so they also lose security guarantees when the KGC is dishonest. By analyzing the security of the certificateless signature scheme proposed by Liang Hongmei et. al. in security analysis and improvement of efficient certificateless signature scheme publicated by Journal fo Computer Applications, 2010,30(3):685-687, where the authors pointed out that the scheme could not resist public key replacement attack under negative dishonest KGC and positive dishonest KGCs attacks. Aiming at these problems, the scheme was improved by the means that KGC generated the users public key and made it public. The analysis of security shows that the improved scheme is able to resist public key replacement attack under negative dishonest KGC, thus successfully distinguishing the positive dishonesty of KGC,and resisting existential forgery on adaptively chosen message attack under the random oracle model.
    Advanced encryption standard and its software implementation on ARM processor
    ZHANG Yuehua ZHANG Xinhe LIU Hongyan
    2011, 31(06):  1539-1542.  DOI: 10.3724/SP.J.1087.2011.01539
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    To improve the efficiency of Advanced Encryption Standard （AES） algorithm on ARM processor, aiming at AES algorithm with 128-bit block length and key length, an optimization method was proposed. The method can speed up execution efficiently on ARM processor while consuming less ROM memory. A theoretical analysis of the Rijndael algorithm and of the proposed optimization was discussed. S box was generated by real-time calculation. The MixColumns and InvMixColumns transformations were amended to execute efficiently on 32-bit processor. On-the-fly key expansion was adapted. Simulation results of the optimized algorithm on S3C2440 processor were presented. The experimental results show that the optimization of AES algorithm can execute efficiently on S3C2440 and consume less ROM memory. The method can be applied to embedded systems with memory constraints.
    Graphics and image technology
    Method of Boolean operation based on 3D grid model
    CHEN Xuegong YANG Lan HUANG Wei JI Xing
    2011, 31(06):  1543-1545.  DOI: 10.3724/SP.J.1087.2011.01543
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    A kind of Boolean operational method based on a three-dimensional grid model was proposed. Firstly, through collision detection algorithm based on hierarchical bounding box tree of Oriented Bounding Box (ORB), the intersecting triangles could be got. Through the intersection test of the triangles, the intersecting lines could be obtained and the intersecting lines topology relations with the triangles could be established. Secondly, a regional division for the intersecting triangles was made through processing the three types of intersecting lines, so as to get a series of polygons, and carry out Delaunay triangulations for polygon to get the result area. Lastly, relation adjacency list was constructed based on solid containing relations, the polygons internal relation and external relation with other entities were judged, and the triangles were located according to the mesh model topology relations. Simultaneously, according to such Boolean operations as the intersection, union, and differences, according to the grid model topology relations were judged, the position of the triangles were judged and then the final results could be obtained. Experimental results show that this algorithm can achieve better results. Experimental results show that the lithology of intersecting parts is consistent with the entities and can verify the correctness and feasibility of the algorithm.
    Image retrieval based on K-means clustering and multiple instance learning
    WEN Chao GENG Guohua LI Zhan
    2011, 31(06):  1546-1548.  DOI: 10.3724/SP.J.1087.2011.01546
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    Aiming at the problem of object-based image retrieval, a novel algorithm named KP-MIL was proposed, which worked in the Multiple Instance Learning (MIL) framework. Firstly, this algorithm clustered the instances in positive set and negative set, and found the potential positive instance and bag structure. Then an alpha coefficient was introduced to trade off between positive instance and bags similarity. Experiments on SIGVAL dataset show that this algorithm is feasible, and the performance is superior to other MIL algorithms.
    Image retrieval based on relevance feedback using blocks’ weighted dominant colors in MPEG-7
    GAO Lichun XU Yeqiang
    2011, 31(06):  1549-1551.  DOI: 10.3724/SP.J.1087.2011.01549
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    In order to improve the defection performance of MEPG-7 Dominant Color Descriptor (DCD) that it is prone to lose the spatial information of colors, in this paper, blocks weighted dominant color descriptor was used, as well as the correlation feedback method was carried out. It used correlation feedback method to adjust weight value of the block and the dominant color feature in the block. Experimental results show that the method is much more effective than those based on only dominant colors and blocks dominant colors without feedback.
    Retinex color image enhancement based on adaptive bidimensional empirical mode decomposition
    NAN Dong BI Duyan XU Yuelei HE Yibao WANG Yunfei
    2011, 31(06):  1552-1555.  DOI: 10.3724/SP.J.1087.2011.01552
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    In this paper, an adaptive color image enhancement method was proposed: Firstly, color image was transformed from RGB to HSV color space and the H component was kept invariable, while the illumination component of brightness image could be estimated through Adaptive Bidimensional Empirical Mode Decomposition (ABEMD); Secondly, reflection component was figured out by the method of center/surround Retinex algorithm, and the illumination and reflection components were controlled through Gamma emendation and Weber's law and processed with weighted average method; Thirdly, the S component was adjusted adaptively based on characteristics of the whole image, and then image was transformed back to RGB color space. The method could be evaluated by subjective effects and objective image quality assessment, and the experiment results show that the proposed algorithm is better in mean value, square variation, entropy and resolution than MSR algorithm and Meylan's algorithm.
    Object-based multilevel image enhancement method
    XU Beilei ZHUANG Yiqi TANG Hualian ZHANG Li TIAN Jinshou
    2011, 31(06):  1556-1559.  DOI: 10.3724/SP.J.1087.2011.01556
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    To solve the problems of the ringing, blocking artifacts and the excessive noise amplification in local image enhancement, an object-based multilevel contrast stretching method was proposed. First, segment the image into its constitent objects by using morphological watersheds and regional merging; then, separately stretch the image contrast at inter-object level and intra-object level in different ways. At inter-object level, an approach of stretching between adjacent extrema was adopted to adequately enlarge the local dynamic range of gray levels between objects; at intra-object level, the linear stretching approach was adopted to enhance the textural feature of the object and keep its appearance. Experimental results show, besides enhancing the image structure, the proposed method can effectively avoid ringing, blocking artifacts, restrict excessive noise amplification in smooth areas and preserve the overall brightness of the image, thus can provide the enhanced image with natural appearance.
    New approach to retinal image enhancement based on Hessian matrix
    YOU Jia CHEN Bo
    2011, 31(06):  1560-1562.  DOI: 10.3724/SP.J.1087.2011.01560
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    The retina vessel enhancement of retina angiography image is considered as an essential factor to improve diagnosis. Therefore, this paper proposed a multi-scale vessel enhancement method for retinal image based on Hessian matrix. Besides, the strategy and process of applying this method were provided. This method was tested on DRIVE database and its results were compared with other methods using the same database. The result shows a considerable accuracy as other methods while obtaining better robustness.
    Fingerprint image fusion iterative enhancement
    LI Chaoyou SUN Jizhou
    2011, 31(06):  1563-1565.  DOI: 10.3724/SP.J.1087.2011.01563
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    Suspect fingerprint images acquired from criminal scenes are often of low quality, or incomplete. The existing algorithms/methods found in literature are not suitable for enhancing these fingerprint images, because these algorithms/methods only perform enhancement once. In this paper, a new method for fingerprint image enhancement was proposed. The proposed method enhanced fingerprint image in Fourier domain and spatial domain by using iterative and wavelet fusion technique. Experimental results indicate that the proposed method significantly improves the performance of fingerprint enhancement — not only was the ridge definition enhanced, but also the ridge fracture was connected and the incompleteness was mended. Therefore, the proposed method is suitable for enhancing low quality fingerprint images.
    Robust 3D reconstruction method based on image sequence
    YANG Jun SHI Chuankui DANG Jianwu
    2011, 31(06):  1566-1568.  DOI: 10.3724/SP.J.1087.2011.01566
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    A robust 3D reconstruction method based on image sequence was presented. First, an optimal parameter estimation of two images was applied. Then, along with the number of images increasing, the sparse bundle adjustment was adopted to reduce the minimum geometric error of the measurements of image coordinates. Finally, the 3D structure and camera parameters were processed with a global optimization method to improve the robustness of the reconstruction. The experiment results demonstrate that the proposed method can effectively improve the accuracy and robustness of reconstruction, and factually represent 3D model of objects.
    Adaptive error concealment algorithm based on residual distribution for whole frame losses in H.264
    DING Zhihong WANG Gang LIU Lizhu
    2011, 31(06):  1569-1571.  DOI: 10.3724/SP.J.1087.2011.01569
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    The H.264 communication over network may cause a whole frame loss. To solve the problem, an error-concealment algorithm based on residual distribution was proposed for whole frame packet loss in H.264. Firstly, the residual information of reference frame was analyzed. Then, according to the result, the motion vector copy algorithm was used in the region where the image was smooth or the image object's motion was rigid. For the other regions, the motion vector of each pixel was re-estimated, and then optical flow algorithm was introduced. Experimental results show that the algorithm outperforms the traditional one on both visual quality and Peak Signal-to-Noise Ratio (PSNR).
    Adaptive image inpainting algorithm based on texture feature
    CHEN Qing WANG Huiqin WU Meng
    2011, 31(06):  1572-1574.  DOI: 10.3724/SP.J.1087.2011.01572
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    In older to solve the problem of the deviation accumulation caused by the restoring process of exemplar-based image inpainting algorithm, and to improve the accuracy of the algorithm, this paper focused on the revision of the priority computation formula, by leading an α factor to enhance the proportion of data. Therefore, the algorithm is more sensitive to the detail of image texture during the inpainting procedure. The average energy of texture feature was quantified by the wavelet coefficients. Thus the α factor was made to be self-adaptive so that the images with different energy could be inpainted adaptively through appropriate strategies. It is proved that the image quality can be enhanced effectively by this improved exemplar-based image inpainting algorithm, and the optical connectivity requirements of human beings can be satisfied by the inpainted effects.
    Research of constraint constant modulus medical CT image blind equalization algorithm
    SUN Yunshan ZHANG Liyi DUAN Jizhong
    2011, 31(06):  1575-1577.  DOI: 10.3724/SP.J.1087.2011.01575
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    In order to improve the Peak Signal-to-Noise Ratio (PSNR) of images, and to raise the reliability and restoration effects of the algorithm, the degradation and restoration process of image was transformed by a linear transform to be equivalent to one dimensional convolution. A constraint constant modulus cost function of blind equalization applied to medical CT images was founded, and its convexity was proved. A blind equalization algorithm based on dimension reduction was proposed. Computer simulations demonstrate the effectiveness of the algorithm. Matrix inversion is avoided to improve the efficiency of operations.
    Lossless image compression coding method based on static dictionary
    GAO Jian SONG Ao LIU Wan CHEN Yao
    2011, 31(06):  1578-1580.  DOI: 10.3724/SP.J.1087.2011.01578
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    In combination with the thoughts of former pixel predictive coding method and Lempel-Ziv-Welch (LZW) coding, in order to tackle the problem of low efficiency on signal compression of signals with high changing frequency, a sort of lossless image compression coding method was proposed. In this method, the correlation between pixels of the picture was used to construct a static dictionary, and the image could be compressed losslessly by looking and coding the data which was formerly predictive coded. The experiment results show that the proposed method is easy to realize and achieves higher compression efficiency than LZW algorithm and WinZIP algorithm.
    New method to interpolate images using Doo Sabin subdivision
    LIANG Yun WANG Dong
    2011, 31(06):  1581-1584.  DOI: 10.3724/SP.J.1087.2011.01581
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    Image interpolation is an important method to magnify images with low resolution to adapt to the target screens. To preserve the geometry feature of the original image is an effective way to improve the quality of magnified images. This paper proposed a new method to interpolate images based on Doo Sabin subdivision. The method adopted the essential idea of subdividing the quadrilateral mesh to enhance the sampling images of low resolution. Firstly, part of the data of high resolution images was obtained by mapping low resolution images. Secondly we classified the unknown pixels of high resolution images according to their geometric features. Then we interpolated all the unknown pixels by the assigned pixels. Values of the unknown pixels were the weighted average of their neighboring pixels. The weighted strategy was deduced by Doo Sabin subdivision. Experiments show that our method can preserve the sharp feature of image edges, decrease zigzags and achieve better results than the previous methods.
    Image interpolation algorithm based on edge degree
    KONG Fanting LIU Junhua
    2011, 31(06):  1585-1587.  DOI: 10.3724/SP.J.1087.2011.01585
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    In order to eliminate the phenomenon of contour jaggies in conventional image interpolation schemes, an edge-degree-based image interpolation method was proposed. Under the smooth contours assumption, the method considered the smoothly varying characteristics of nature image contours, and utilized the information of edge degree to suppress contour jaggies. Simulation results show that the proposed method produces fewer jaggies, and it doesn't introduce other obvious artifacts. Furthermore, the method still preserves the simplicity and efficiency of conventional image interpolation methods, and is easy for implementation and application.
    Image identification method based on local time series of intersecting cortical model
    LI Jianfeng ZOU Beiji LI Lingzhi XIN Guojiang
    2011, 31(06):  1588-1591.  DOI: 10.3724/SP.J.1087.2011.01588
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    The time series of Pulse Coupling Neural Network (PCNN) is widely used in the image retrieval and identification, but it cannot embody the shape and characteristics of the image, which results in the failure of image evaluation. In this paper, the local time series of cross visual cortex was proposed to solve the problem. Fist, the image was divided into blocks; then, the time series of each block was extracted; last, the local time series were linked to global time series. The proposed algorithm was compared with the basic time series and the time series added with edges information. The experimental results demonstrate that the proposed method can effectively and efficiently solve the problems existing in the basic time series.
    Texture feature extraction by incomplete tree-structed wavelet based on morphology pre-processing
    ZHANG Wen GE Yurong
    2011, 31(06):  1592-1594.  DOI: 10.3724/SP.J.1087.2011.01592
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    Low operation speed and being only fit for high quality images are the disadvantages of incomplete tree-structured wavelet. To deal with this problem, a new algorithm was proposed. Firstly, pre-processment using tophat-bothat was done to clear noise and to enhance contrast degrees; then the feature consistency was extracted. If its value was high, only one part of the image would be used in incomplete tree-structured wavelet. Otherwise, the whole image would be used. Lastly, Double Probabilistic Neural Network (DPNN) ws adopted here to identify images. Brodatz database was used for simulation, and the algae images pictured at scene was used as an application of this method. Result shows that this algorithm is fast in feature extraction and identification, with especially good performance at low quality images.
    Image features correspondence based on voting of geometric constraint
    HAN Liru
    2011, 31(06):  1595-1597.  DOI: 10.3724/SP.J.1087.2011.01595
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    In order to improve the performance of the image features correspondence that solely depends on similarity, a correspondence algorithm is proposed, which used the geometric constraint efficiently by the voting method. First of all, a fast coarse matching by the descriptor of the features was performed to get the candidate correspondence, then a robust geometric constraint was used to compute a new similarity of the candidate correspondence by the voting method. Finally, a self-adaptive method for distinguishing the belief of the candidate correspondence was proposed to get the correspondence of image features. Comprehensive experiments demonstrate that our method is effective and robust for a variety of image transforms. Better result can be got by the correspondence algorithm based on voting of geometric constraint than that based on similarity simply.
    Multi-focus image fusion algorithm based on region energy framework
    FAN Dongyan
    2011, 31(06):  1598-1601.  DOI: 10.3724/SP.J.1087.2011.01598
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    In the multi-focus image fusion algorithm based on wavelet transform, the quality of fused images is usually reduced due to the discrepancy between the adjacent pixels. According to the transform domain of the fusion rule, the eigenvalues of region energy were extracted by using the coefficients of the wavelet transform, and the global match degree was regarded as a way to determine the fusion rules. A new fusion algorithm based on region energy framework was proposed. To improve the quality of fused images, the consistency of the source of each wavelet component was detected. Finally, the algorithm was simulated in experiments. The results verify that this algorithm has better fusion effects than those based on weighted average, selecting the largest gray value and region energy.
    Targets tracking based on mixture particle filtering
    HU Xueyou TAO Liang NI Minsheng
    2011, 31(06):  1602-1604.  DOI: 10.3724/SP.J.1087.2011.01602
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    Multiple targets tracking is an important task in the field of computer vision. To overcome the strong dependence of evaluating effects on the initial selection of the sample, Harris corner detector was used to detect the feature point in the frames, at the same time, KLT tracker was used to match the feature point in the consecutive two frames; Then, Mean shift algorithm was applied to cluster and locate the feature points which were matched by KLT algorithm. Furthermore, Mean-shift algorithm was combined with the particle filter, and a mixture particle filter based on Mean-shift was proposed. The detailed algorithm was given in this paper and it was applied in the multiple targets tracking. Finally, the experiment has testified the validity of the method.
    Facial expression recognition algorithm fused ICA and support vector clustering
    ZHOU Shuren LIANG Ximing
    2011, 31(06):  1605-1608.  DOI: 10.3724/SP.J.1087.2011.01605
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    A new method of facial expression recognition is proposed, which is based on Independent Component Analysis (ICA) and Support Vector Clustering (SVC), which aims at solving the problem of features extraction of facial expression and auto-clustering. First, the facial expression features were extracted by ICA, and then the radius of Locally Constrained Support Vector Clustering (LCSVC) could be acquired according to the adjustment of inter-parameter Mixture of Factor Analysis (MFA) method. This clustering method effectively restrained the disturber of the clustering boundary region and also was better than the one that only uses SVC. The test sample is classified by a comparison with the difference between new and old radius, and the experimental results show that the proposed method is effective and successful.
    Palmprint recognition method based on localized non-negative sparse coding
    SHANG Li SU Pingang DU Jixiang
    2011, 31(06):  1609-1612.  DOI: 10.3724/SP.J.1087.2011.01609
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    To more effectively extract localized features of images, on the basis of the traditional Non-negative Sparse Coding (Hoyer NNSC) algorithm, a novel localized NNSC (LNNSC) algorithm with sparse constraint was proposed. This algorithm considered the sparse measure constraint of feature basis vectors and the maximized representativeness of features, and could obtain the strengthened localized image features. At the same time, this algorithm utilized the Laplace density model as the feature coefficients sparse punitive function to ensure an image's sparse structure. Furthermore, on the basis of feature extraction, by utilizing the Radial Basis Probabilistic Neural Networks (RBPNN), the palmprint recognition task could be implemented automatically. Compared with the palmprint recognition methods of Non-negative Matrix Factorization (NMF), Local NMF (LNMF) and Hoyer-NNSC, simulation results show that our method proposed here displays feasibility and practicality in palmprint recognition.
    Detection of human body based on local gray entropy
    LI Wei ZHAO Yu CHEN Jiaxin HU Minghe
    2011, 31(06):  1613-1616.  DOI: 10.3724/SP.J.1087.2011.01613
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    With regard to the two main factors that cause the difficulty of human-detection under the dim contrast environment, a concept of the local gray entropy was introduced, and then an algorithm of human target detection based on local gray entropy was proposed for the reason that the local gray entropy could reflect the discrete level accurately, and it was independent on the average gray. After the background model was established, the local gray entropy difference between the moving objects and background model inside the domain windows was calculated by using calculation formula of local gray entropy simplified through Taylor expansion. And the ratio of detection and the ratio of false-alarm of the algorithm were evaluated. The optimal thresholds on the differential of the local gray entropy which could get the human body under the two conditions of low contrast were obtained. The experimental results show that the algorithm of human target detection based on the trait of the local gray entropy can obtain the moving human targets effectively under the dim contrast environment.
    Big skin exposure detection for adult image filtering
    YE Lihua
    2011, 31(06):  1617-1620.  DOI: 10.3724/SP.J.1087.2011.01617
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    With regard to the features of the big skin exposure in the adult images, we propose a hybrid detection approach which is composed of such three parts as color filtering, texture filtering and geometry filtering. A subsection processing skin color model was used to filter the non-skin color pixels and get the candidate skin regions. Then a coarse-degree-based texture filtering was used to filter the pixels with rough texture and skin color tone. At last we filtered the skin-like region (such as deserts or beaches) by fractal dimensions. The experimental results indicate this approach has high detection ratio and high precision.
    Center extraction of Placido image based on curve fitting
    GAO Shaolei SHEN Jianxin ZHOU Hongya
    2011, 31(06):  1621-1623.  DOI: 10.3724/SP.J.1087.2011.01621
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    Center extraction is a primary stage in the extraction of Placido image. Therefore, a curve fitting method is proposed to detect the center. Firstly, Hough transform was used to locate the approximate center, and Placido image was located in the polar coordinate. Then the Gaussian kernel function was convolved with the image, and the points were detected in the polaraxis. Finally, based on the coordinates of these points, the accurate center was obtained by the ellipse fitting method. The precision can be brought to the order of sub-pixels by this algorithm and the mean error of diopter is less than 0.25D. Extracting results show that proposed method has higher accuracy and better robustness and provides guarantee on the precise corneal topography.
    Method of weather recognition based on decision-tree-based SVM
    Li Qian FAN Yin ZHANG Jing LI BAOqiang
    2011, 31(06):  1624-1627.  DOI: 10.3724/SP.J.1087.2011.01624
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    To improve the quality of video surveillance outdoors and to automatically acquire the weather situations, a method to recognize weather situations in outdoor images is presented. It extracted such parameters as power spectrum slope, contrast, noise, saturation as features to realize the multi-classification of weather situations with Support Vector Machine (SVM). Then a decision tree was constructed in accordance with the distance between these features. The experimental results on WILD image base and our image set of eight hundred samples show that the proposed method can recognize sunny, overcast, foggy weather more than 85%, and recognize rainy weather more than 75%.
    Detection of image region-duplication forgery based on gray level co-occurrence matrix
    OU Jiajia CAI Biye XIONG Bin LI Feng
    2011, 31(06):  1628-1630.  DOI: 10.3724/SP.J.1087.2011.01628
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    With regard to the copy-move forgery of image region, this paper proposes a detection algorithm based on gray level co-occurrence matrix. Firstly, we divided the detected image into multiple overlapping blocks with same sizes, represented the textural features of each block with the statistics of its gray level co-occurrence matrix, and got the feature vector of the image. Secondly, we sorted the feature vector by dictionary, and located the tampered region by utilizing the displacement vectors of image blocks. Lastly, experimental results show that our algorithm performs better than the classical detection algorithm based on Principal Component Analysis (PCA) in terms of the processing against rotate operation and of efficiency.
    Maximizing projection grating slit for document image skew detection
    ZHAO Fei XIE Liyang LI Jia
    2011, 31(06):  1631-1633.  DOI: 10.3724/SP.J.1087.2011.01631
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    Skew document images often appears when it is captured by image acquisition devices such as cameras or scanners, which may induce recognition mistakes by Optical Character Recognition (OCR) software. The paper proposed an optimized method for the skew detection of document images, and its objective function is the image projection grating slit width. The document image angle is the inverse of the projection angle, when the corresponding projection grating slit width is the largest. The detection range is expanded and the detection speed is increased by the grating line width function. The amount of calculation in detection is decreased by preliminary projection on equispaced rows and back projection. The detection precision is improved by dichotomy. In the experiments document images where a few illustrations were used, and the skew detection results show the proposed method is of high efficiency and robustness.
    Artificial intelligence
    Multiple variable precision rough set model
    LU Qiuqin HE Tao HUANG Guangqiu
    2011, 31(06):  1634-1637.  DOI: 10.3724/SP.J.1087.2011.01634
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    In order to solve the problem that the domain partition of Zaike variable precision rough set can not overlap, an expansion was made on the domain of Zaike variable precision rough set based on multi-set, a multiple variable precision rough set model was put forward, and its corresponding definitions, theorems and properties were fully described, which included definitions of multiple domain and multiple variable precision approximate sets, proofs of their properties, and relations between multiple Zaike variable precision rough set and multiple variable precision rough set. These definitions, theorems and properties have not only differences but also relations between multiple variable precision rough set and Zaike variable precision rough set. Multiple variable precision rough set can fully describe overlap among knowledge particles, difference of significance among objects and polymorphism of objects, and can conveniently find associated knowledge from data saved in a relation database, having one-to-many and many-to-many dependency, and thought to have no relations.
    Integration method of qualitative probabilistic networks based on rough sets
    LV Yali SHI Hongbo
    2011, 31(06):  1638-1640.  DOI: 10.3724/SP.J.1087.2011.01638
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    Qualitative Probabilistic Network (QPN) is a powerful knowledge representation tool. However, sub-QPN can only represent sub-domain knowledge. To build a large QPN to represent the whole domain knowledge, an integration method of multiple sub-QPNs that have different nodes was proposed based on rough sets. Specifically, a single variable or a combination of multiple variables in a QPN could be regarded as an attribute in rough sets. First, multiple sub-QPNs were combined into an initial integrated QPN during integrating, then the directed edges and qualitative signs were added into the QPN according to attribute dependency degree, and then some unnecessary edges of which child node had multiple parent nodes could be deleted according to relative necessity of attribute. Thus, a large integrated QPN would be obtained to represent the whole domain knowledge. Finally, the experimental results illustrate that the integration method is feasible and effective.
    Dynamic feature research into simplifying technology of Petri nets
    YAN Bozhao YUE Xiaobo ZHOU Kaiqing MO Liping
    2011, 31(06):  1641-1644.  DOI: 10.3724/SP.J.1087.2011.01641
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    For the large and complicated Petri nets, the main problem hindering the technology development is always that "too many nodes lead to station explosion". Therefore, how to simplify Petri nets effectively has always been a research focus and to simplify it to be several subnets is a very effective method. With the decomposition method of Petri nets by defining an index function on the place set, this paper gave the decomposed definition of Petri nets and proposed the related algorithms. Based on the above research, according to the dynamic feature of simplifying technology via researches of the given algorithms, the authors studied the special properties of subnet correspondingly and provided an efficient approach to analyze the Petri nets of complicated systems.
    New method for maximum distribution reduction in inconsistent decision information systems
    YU Chengyi LI Jinjin
    2011, 31(06):  1645-1647.  DOI: 10.3724/SP.J.1087.2011.01645
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    In order to get the maximum distribution attribute reduction rapidly in inconsistent decision information systems, a new decision maximum distribution binary relation was defined after analyzing the existing methods. And the judgment theorems for judging maximum distribution consistent sets were obtained, from which we can provide a new maximum distribution attribute reduction algorithm in inconsistent decision information systems. Moreover, the characterization of core attributes, relative necessary attributes, unnecessary attributes were discussed based on decision maximum distribution binary relation. Finally, a case study illustrates the validity of the method.
    Hybrid PSO-Solver algorithm for solving optimization problems
    GAO Yanhui ZHU Kejun
    2011, 31(06):  1648-1651.  DOI: 10.3724/SP.J.1087.2011.01648
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    Combined Particle Swarm Optimization (PSO) and Solver add-in, this paper proposed a hybrid PSO-Solver algorithm to solve the optimization problems. As a global search algorithm, PSO looks for the global feasible solution, and Solver is a local search tool based on gradient information, which refines the solution obtained by PSO. The hybrid algorithm could speed up the global search, as well as avoid getting into local minima. VBA was used to code, which is simple and easily conducted. Results of solving some unconstrained and constrained examples, compared to the standard PSO and other heuristic algorithms, show that this hybrid PSO-Solver algorithm can improve the speed of convergence and the accuracy of solutions significantly.
    Optimal solution to distribution decision problem of distribution centre by artificial fish swarm algorithm
    FANG Jincheng ZHANG Qishan
    2011, 31(06):  1652-1655.  DOI: 10.3724/SP.J.1087.2011.01652
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    This paper analyzed and established mathematical models for distribution decision problem of distribution centre from the perspective of economical distribution. It put forward an improved application of artificial fish swarm algorithm based on real coding. Through the analysis of coding design, the optimization solution steps of the algorithm were discussed in detail. Finally, the paper testified the effectiveness of the models and its solution algorithm by using genetic algorithm to solve the same calculation examples.
    Scheduling of imaging satellites based on improved ant colony algorithm
    LI Hongxing DOU Yajie DENG Hongzhong TAN Yuejin
    2011, 31(06):  1656-1659.  DOI: 10.3724/SP.J.1087.2011.01656
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    Scheduling of Imaging Satellite (IS) involves many complex constraints. In the battle fields, it is difficult to schedule imaging satellites to satisfy the requirement of strategic decision-making. In view of this problem, an algorithm based on an improved ant colony algorithm with elitist strategy, which focused on the scheduling problem of multiple imaging satellites, was proposed. A specific description on the algorithm's state transformation rules and pheromone update rules was given. A disposal flow of task roadmap based on heuristic method was proposed to generate scheduling plan and evaluate the roadmap, and the result of which fed back to the path search phase. A case was given to compare the proposed algorithm with greedy algorithm and genetic algorithm to validate that this one can help acquire results of high quality.
    Artificial immune network clustering based on affinity accumulation
    PAN Zhangming
    2011, 31(06):  1660-1663.  DOI: 10.3724/SP.J.1087.2011.01660
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    Artificial immune network clustering is often ineffective when there is noise or undefined cluster boundary in the data. Enlightened by the diversity of immune system, an artificial immune network clustering method based on affinity accumulation was proposed. The method introduced the idea of affinity accumulation and effective evolution strategies into antibodies, and used affinity accumulation in antibodies to describe the distribution trend of spatial density of data. It resulted in a clear cluster structure for the memory network with the effect of secondary immunity. The experimental results show that, the method is effective in clustering while dealing with undefined boundary problems, and is powerful in avoiding noise.
    Database technology
    Domain ontology construction method based on knowledge graphs
    CHEN Kun ZHANG Lei
    2011, 31(06):  1664-1666.  DOI: 10.3724/SP.J.1087.2011.01664
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    This paper proposed a domain ontology construction method based on knowledge graphs. This domain ontology was constructed based on the mature idea of software engineering by using the "HowNet" as the semantic knowledge resources, and knowledge graphs as a semantic representation. It has a clear structure with clear semantic meaning. It can provide effective supports for some applications such as semantic Web and information extraction. This paper introduced the concept of ontology, the standard of design, the process of modeling, and future prospects of ontology portability. This method was proved to be more effective than traditional ontology construction method in uncertain knowledge processing by experimental results.
    Method for personalized user profiling in social tagging systems
    XIA Ningxia SU Yidan QIN Hua ZHANG Min
    2011, 31(06):  1667-1670.  DOI: 10.3724/SP.J.1087.2011.01667
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    As for the disadvantages of available user interests modeling methods in social tagging systems: always use a set of scattered tags to represent users' interests but ignore the combination use of tags, a new user modeling method was proposed, which introduced co-occurrence techniques into the naive approach. The proposed method added some tag pairs on the basis of naive approach to user model, which reflects tags relationship and considers tags weight. The experimental results on dataset PKDD2009 show that the new model can achieve a higher precision and recall rate, which outperforms the nave method and co-occurrence method.
    Features for semantic role labeling of nominal predicates in Chinese
    XU Jing LI Junhui ZHU Qiaoming LI Peifeng
    2011, 31(06):  1671-1674.  DOI: 10.3724/SP.J.1087.2011.01671
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    Compared to verbal predicates，the structure between nominal predicates and their roles in Semantic Role Labeling (SRL) is more flexible and complex. In this paper, some new word-related and syntactic features were explored from various nominal predicate-specific features to capture the structure information for nominal SRL. The experimental results show that the proposed nominal SRL system achieved the performance of 73.99 in F1-measure on gold parse trees and gold predicates, and outperformed the state-of-the-art nominal SRL. However, the performance dropped to 57.16 in F1-measure on automatic parse trees and automatic predicates. Finally, the training data were augmented with verbal SRL instances to examine whether nominal SRL could benefit from verbal instances. The experimental result show, however, adding verbal SRL instances does indeed improve the performance of nominal SRL, although the improvement is not statistically significant.
    Accurate property weighted K-means clustering algorithm based on information entropy
    YUAN Fuyong ZHANG Xiaocai LUO Sibiao
    2011, 31(06):  1675-1677.  DOI: 10.3724/SP.J.1087.2011.01675
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    Concerning the initial clustering center generation and the data similarity judgment basis of the traditional K-means algorithm, the paper proposed an accurate property weighted K-means clustering algorithm based on information entropy to further improve the clustering accuracy. First, property weights were determined by using entroy method to correct the Euclidean distance. And then, high-quality initial clustering center was chosen by comparing the empowering target cost function of the initial clusters for more accurate and more stable clustering. Finally, the algorithm was implemented in Matlab. The experimental results show that the algorithm accuracy and stability are significantly higher than the traditional K-means algorithm.
    Classification model based on mutual information
    ZHANG Zhen HU Xuegang
    2011, 31(06):  1678-1680.  DOI: 10.3724/SP.J.1087.2011.01678
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    Concerning the relevance between the attributes and the contribution difference of attribute values to attribute weights in classification dataset, an improved classification model and the formulas for calculating the impact factor and sample forecast information were proposed based on mutual information. And the classification model predicted the unlabelled object classes with the sample forecast information. Finally, the experimental results show that the classification model based on mutual information can effectively improve forecast precision and accuracy performance of classification algorithm.
    Key technologies of dynamic information database for power systems
    HUANG Haifeng ZHANG Keheng ZHANG Hong JI Xuechun CHEN Peng
    2011, 31(06):  1681-1684.  DOI: 10.3724/SP.J.1087.2011.01681
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    In the paper, on the basis of analyzing the structure of dynamic information database, and in combination with the feature of the power system, the key technologies of concurrency data processing, memory-mapped file, disk cache management mechanism and associated data storage were discussed, and the data sampling flow and hybrid compression algorithm were also introduced in detail. The application case in the automatic system of power grid dispatching was introduced and the result proves that the dynamic information database can meet the performance requirement of high-speed data processing.
    Typical applications
    Co-evolution theory and its application in fertilization model
    ZHENG Gaowei LI Miao GAO Huiyi LI Lujiu
    2011, 31(06):  1685-1688.  DOI: 10.3724/SP.J.1087.2011.01685
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    Due to the limitation of the fixed mathematical structure, it can not fit all the data; as a result, some experimental results may be discarded in constructing fertilization model, which results in a waste of some data. To solve these problems, the algorithm of fertilization construction model based on co-evolution theory was proposed. The algorithm divided the whole construction model problem into two sub-problems: model structure construction and model parameter optimization. In addition, the two sub-problems were abstracted as co-evolution among various groups. The processes of using genetic programming to construct the model structure and genetic algorithm to optimize the model parameters were carried out in collaboration. The results show that the algorithm not only generates the dynamic model automatically based on the historical experimental data but also has higher accuracy.
    Two-stage segment optimal packing of single size rectangles
    JIANG Yongliang YANG Zhiqiang ZHANG Chengyi
    2011, 31(06):  1689-1691.  DOI: 10.3724/SP.J.1087.2011.01689
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    A two-stage approach was proposed which can solve the optimal packing of single size rectangles effectively. The best cutting patterns of standard sub-segment were solved and the problem was transformed into one-dimensional cutting stock problems in the first stage. In the second stage the best ideal solution was found with different methods for the one-dimensional cutting stock problems. With this method, an optimal packing of single size rectangles system was developed. The system not only can solve the segment layout of single size rectangles but also can solve other kinds of optimal packing of single size rectangles. Enterprise applications show that this method is an effective solution to the problem of single size rectangles packing.
    Automatic classification approach to road alignment features
    LI Huiying CAO Kai WANG Xiaoyuan
    2011, 31(06):  1692-1695.  DOI: 10.3724/SP.J.1087.2011.01692
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    Updating road information database in the sustainability, a road alignment identification model based on LVQ-Boosting approach was proposed, which utilized a large number of path tracking trajectory data generated by car GPS for capturing quickly changes in road information. The approach further improved the generalization ability of LVQ and obtained a classifier with strong classification performance through employing weak classification algorithm. Thus, the purposes for identifying automatically the features of the road alignment and fast grouping the road feature type were implemented. The experimental results show that the approach has high efficiency and accuracy of the road alignment identification.
    Vehicle power system condition prediction based on weighted hidden Markov model
    CHENG Yanwei XIE Yongcheng LI Guangsheng
    2011, 31(06):  1696-1698.  DOI: 10.3724/SP.J.1087.2011.01696
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    A new condition prediction approach based on weighed Hidden Markov Model (HMM) was presented in order to solve the problem of trend prediction for vehicle power system. Through the establishment of the power system HMM, the hidden state of HMM was predicted by weighted prediction method, and the observed state of the model was calculated by the observation probability density of the maximum probability hidden state. The approach was applied to the state prediction of rate turn of the system voltage adjusting pulse width signals, and was compared to that of using BP (Back Propagation) neural network and Auto-Regression (AR) prediction model with the same sequence. The results show that the method has better prediction on the system state change.
    Unscented Kalman filter for on-line estimation of Jacobian matrix
    ZHANG Yingbo
    2011, 31(06):  1699-1702.  DOI: 10.3724/SP.J.1087.2011.01699
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    In image based robot visual servo system， image Jacobian matrix is commonly used for calibration. Using on-line image Jacobian matrix estimation method， the complex system calibration can be avoided without knowing the accurate system models. In this paper， the author proposed to use the Unscented Kalman Filter (UKF) for on-line estimation of total Jacobian matrix for the sake of improving the tracking accuracy of the robots which is tracking a moving object. In order to evaluate the performance， three algorithms using Kalman Filter (KF), Particle Filter (PF), and UKF were used for total Jocobian matrix estimation in a 2-Degree Of Freedom (DOF) robot visual servo platform. The experimental results show that the UKF algorithm outperforms the other two in accuracy while its time cost is very much close to the KF algorithm.
    3D simulation of bending tree branch and fractal tree root
    ZHANG Jie LIN Bin CAI Wenqi XIE Zhuangrong
    2011, 31(06):  1703-1705.  DOI: 10.3724/SP.J.1087.2011.01703
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    The shape of a tree is mostly determined by the reality to the nature layout of branches. In order to simulate a 3D tree branch to mimic the natural tree shape, using the theory of fractal algorithm and mechanics of material, a simulating method for the 3D's bending branch and fractal root based on the gravity field was proposed. The stress state of the branch was reflected by its bending degree. Bending degree could be controlled by changing the value of Young's modulus. Also, with X3D and Java, fractal algorithm combined with Extrusion node of X3D was used to simulate the geotropism of the bending root. A realistic 3D tree can be easily created with some input data using our simulation. By using the close relationship of the tree's underground part and upper part, a simulation method of gravity's effect on the tree shape was established. The experimental results show that the method can easily generate realistic three-dimensional form of fractal trees.
    Improved image preprocessing algorithm based on FPGA
    ZHANG Peng ZHONG Jun GUO Anming PENG Qiang
    2011, 31(06):  1706-1708.  DOI: 10.3724/SP.J.1087.2011.01706
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    In order to preprocess the monitoring image, the image preprocessing was studied. Grayscale and binarization algorithm are highly complex, difficult to achieve and cost large computation. The weighted average method was redesigned, of which the floating-point computation was simplified to fixed-point for the benefit of achieving FPGA. An improved function based on Otsu algorithm was proposed and it was proved to be equivalent to Otsu algorithm. Moreover, the preprocessing algorithm was easy to be realized via hardware. After the Verilog programming, the algorithm was simulated on Matlab and ModelSim. The result demonstrates that the new algorithm is effective and achievable. Therefore, the design can be used as a preprocessing module of a real-time image processing system. As a result, it will save lots of time for the computations after preprocessing.
    Position and pose estimation of aerial vehicle based on terrain elevation model
    LIAO Wei WENG Lubin YU Junwei TIAN Yuan
    2011, 31(06):  1709-1712.  DOI: 10.3724/SP.J.1087.2011.01709
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    In order to solve the problems that scene matching cannot be applied to navigation and Inertial Navigation System (INS) pose information cannot be effectively used, a new approach based on the digital terrain elevation model was proposed to estimate the absolute position and pose for aerial vehicle. Firstly, the stereo pairs were captured by the airborne camera system and the information of flight speed was acquired by sensors; secondly, the terrain information under the vehicle was obtained by modifying the dual camera motion model; finally, a method used to match the on-board terrain elevation model data based on the rigid-body constraint of the 3D reconstruction results was proposed, which was used to estimate the position and pose of the vehicle in the world coordinate system. The simulation results demonstrate that the improved dual camera motion model achieves better precision, making the estimation of position and pose in the world coordinate system more effective and efficient.
    Computer aided pattern designing system for full-electronic flat machine
    YANG Yihong JIN Yongmin WAN Zhiping
    2011, 31(06):  1713-1715.  DOI: 10.3724/SP.J.1087.2011.01713
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    In order to meet the requirement of developing a full-customized pattern designing system for the full-electronic flat machine, after introducing the basic principles of the full-electronic flat machine and the role of the computer aided pattern designing system in the flat machine system, the software framework and main modules were analyzed. And by using the object-oriented method, the key data structure and program flows involved in the designing system were focused on, the full-electronic flat machine was realized finally. In the application with the relative flat machine, it is confirmed that relative designing jobs can be finished by utilizing this designing system.
    Energy-saving control of parallel computer cluster
    HE Chunshan
    2011, 31(06):  1716-1718.  DOI: 10.3724/SP.J.1087.2011.01716
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    In order to save the energy in using the parallel computer cluster, a scheme was presented in which Open Portable Batch System （OpenPBS） was used to control the parallel computers' boot and shutdown automatically. Homeostasis can be achieved between task computing and energy saving.
    High accuracy sequence of event system based on GPS
    LIN Dan WANG Wenhai
    2011, 31(06):  1719-1722.  DOI: 10.3724/SP.J.1087.2011.01719
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    In order to meet the resolution requirement of hundreds of microseconds，microsecond global clock synchronization must be achieved in Sequence of Event (SOE) system. By means of assessing the existing clock synchronization methods and analyzing the cause of the error in the clock synchronization process, a new method based on the combination of improved Network Time Protocol (NTP) server synchronization and 1PPS synchronization was proposed. That is: advanced NTP server was used to eliminate the clock error between the control stations, "cross-second" phenomenon was avoided in this situation; 1 PPS was used to synchronize the millisecond counters in order to eliminate the crystal accumulated error of Field Programmable Gate Array (FPGA). This method is simple, precise and stable. The resolution of SOE system by using this technique can be up to 0.5 ms, and it has been applied to the turbine protection system in a power plant successfully.
    Linear quadratic control based on stochastic robustness design for hypersonic vehicles
    TAN Yilun YAN Jie
    2011, 31(06):  1723-1726.  DOI: 10.3724/SP.J.1087.2011.01723
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    A linear quadratic control method based on stochastic robustness design was proposed according to the features that hypersonic vehicle model is highly nonlinear，input/output have strong coupling without certain parameters. This control scheme is based on system control requirements, using Monte Carlo simulation method to establish stochastic robustness cost function, and adopting genetic algorithm to optimize the control system design parameters. This formulation can ensure the longitudinal flight stability and improve the control performance of hypersonic vehicles. The controller was demonstrated in closed loop simulations based on an existing longitudinal hypersonic vehicle model. The simulation results show that the controller successfully tracks the reference trajectories, meets the system needs and has strong robustness.
    Optimal algorithm for FIR digital filter with canonical signed digit coefficients
    TAN Jiajie HUANG Sanwei ZOU Changqin
    2011, 31(06):  1727-1729.  DOI: 10.3724/SP.J.1087.2011.01727
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    In order to save the resources of the Finite Impulse Response (FIR) filter and increase the running speed, it was proposed to use the Least Mean-Square-Error (LMSE) to transfer the float point coefficients filter to the Canonical Signed Digit (CSD) filter. The FIR filter was implemented by the cascades structure, which conjugated pairs of zeros into two basic sections. First, all zeros of the digital filter were calculated, which were made of two cascade sections for an FIR. And then the coefficients of the first cascade were transferred to fixed point. Next step was to quantize the second cascade coefficients into fixed point. To eliminate the finite word-length effects, the LMSE was adopted to compensate zeros in this step. Finally, all the fixed point coefficients were quantized into CSD. In order to prove the effectiveness of the two methods, and the FIR filter was also designed with simple quantized coefficients. The magnitude responses of two methods show that the LMSE quantization is more effective than that of the simple quantization.
    Automatic recognition of radar pulse modulation
    YONG Xiaoju ZHANG Dengfu WANG Shiqiang
    2011, 31(06):  1730-1732.  DOI: 10.3724/SP.J.1087.2011.01730
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    In order to achieve the automatic recognition of the pulse modulation of radar, a new method to simplify the figure of the results of time-frequency analysis to extract features was proposed, and then Support Vector Machine (SVM) was used to sort them according to the features. Firstly, extracted the points with useful information; secondly, found the center of each column of useful points; lastly, sampled these centers at the same length, so the figures were transformed to curves with the same length, and the dimensions of the feature of SVMs had been sharply decreased. The simulation results show that the pulse modulation of radar can be recognized with a high accuracy by the algorithm of this paper. Additionally, this method can tolerate the noise, and the accuracy can be kept at a high level while the SNR (Signal-to-Noise Ratio) is low.
2024 Vol.44 No.4

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