Table of Content

01 August 2007, Volume 27 Issue 8

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Network and communications

Clock synchronization technique according to precision time protocol

2007, 27(8):  1828-1830. 

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The Precision Time Protocol (PTP) of the IEEE 1588 protocol provides an effective technique to synchronize the master clock and the slave clock. Collect and process the time stamp in network drives based on PTP, then synchronize the master and slave clock by using the best master clock algorithm programmed in Java and C language. Allan variance was used to describe properties of the clock.

RNP2P—A replica networkbased unstructured P2P system

2007, 27(8):  1831-1834. 

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According to the attributes of resource layout in unstructured P2P system, a replica networkbased unstructured P2P system named RNP2 was proposed. The information of replica was coordinated among peers who store the replica by query feedback, active probing and reverse probing. The related data structure was established to keep the pointers of several other replicas. Through this resource management mechanism, the resource locating usually obtains 100% hit rate at the cost of locating only 3-5 replicas on average. Any query paradigm can incorporate with RNP2P efficiently. The simulations show that the search performance of RNP2P is far higher than that of other paradigms. When k-random walks-based query was adopted, RNP2P needs only 5% message overhead and far below that of flooding query. The query delay of RNP2P is reduced too.

Target localization scheme for cluster-based beaconless WSN

2007, 27(8):  1835-1838. 

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A beacon-less location discovery scheme was proposed due to the following observations: sensors are usually deployed in groups and sensors from the same group may land in different locations that follow a probability distribution. With this prior deployment knowledge, a model was built to reflect inherence information between positions of the object and observations provided by alert sensors. Also a prediction model was set up to offer prior knowledge about moving patterns of the object. Generally speaking, the Bayes rule provides us a suitable way to combine those two kinds of knowledge so as to generate a conditional distribution. By applying the Maximum Likelihood Estimation (MLE) method to this distribution, the objects accurate positions could be estimated. Experimental results prove that the scheme can get better effect.

Energy-efficient algorithm for virtual backbone construction in wireless sensor network

2007, 27(8):  1839-1841. 

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An energy-efficient algorithm for virtual backbone construction that could be used for Wireless Sensor Network (WSN) routing was proposed. The network nodes were divided into a number of clusters according to the geographical distance between them, the distance of the cluster head and members was k-hop. While the size of cluster was increased, the cost of communication was reduced. Using the smallest connected dominating set theory to optimize within the cluster structure, choosing a new parameter value as a right, making the nodes with higher energy be key nodes while guarantee the size of the network backbone, the energy consumption was balanced, and the life of the network was prolonged. Simulation results show that the algorithm can reduce the network scale and routing complexity, and extend the life of WSN.

Web replacement policy based on prediction

2007, 27(8):  1842-1845. 

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To improve the performance of Web Cache, a new cache replacement policy named P-Re by importing a prediction mechanism was proposed. Guided by Prediction by Partial Match (PPM) model, P-Re replaced those nonpredicted requests with smaller keys when the cache had not enough space to accommodate new requests. The simulation shows that the P-Re replacement algorithm can achieve relatively higher Hit Rate (HR) and Byte Hit Rate (BHR) than the cache replacement policies that have no prediction mechanism.

Doppler power spectrum of fading signals in MIMO channels

2007, 27(8):  1846-1848. 

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Classical Doppler Power Spectral (DPS) is not applicable because there are many kinds of distribution of Power Azimuth Spectrum (PAS) in MIMO system. Respective analytical and general expressions were derived according to different commonly-used PASs of uniform, cosine, Gaussian and Laplacian distribution. DPSs of different PAS were compared by simulation, and then the effects of various parameters were analyzed. These extend the research of representation of frequency scattering in MIMO channel.

Data gathering algorithm based on polymorphic ant colony in WSN

2007, 27(8):  1849-1851. 

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Wireless Sensor Networks (WSN) has the characteristics of energy limit. A balanced energy consumption algorithm for WSN was proposed and simulated by using polymorphic ant colony principle in data query and aggregation. Simulation results show that the proposed algorithm can effectively extend life cycle when executing data query and aggregation.

Macro pricing strategy of grid resource based on dynamic equation analysis

2007, 27(8):  1852-1854. 

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A macro pricing strategy based on dynamic equation analysis was presented for grid resource pricing research, which adopted static equation analysis but ignored dynamic equation analysis and macro pricing. Firstly, nonlinear and disequilibrium pricing model was constructed by integrating the grid characteristic. Then the dynamic and stability of this model were analyzed, and macro pricing strategy was presented according to result of analysis. The experimental results indicated the existence and stability of the model and the correctness of the macro pricing strategy.

Energy aware MAC technique for wireless sensor networks based on RFID

2007, 27(8):  1855-1857. 

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By integrating RFID into a Wireless Sensor Network (WSN), the nodes of sensor that can read RFID tags were designed. Then, an energy-saving MAC protocol named CSMAC for WSN based on RFID was proposed based on cluster structure. This protocol with energy-saving and radio-oriented features raised the channel's efficiency of communication by decreasing the collisions. At the same time, it improved the energy efficiency of the network by reducing transmission time, listening monitoring time, and cutting down switching power conversion time. Simulation results show that, compared to the traditional MAC protocol, the proposed protocol can enhance channel utilization and energy efficiency.

Network traffic collection system based on packet filtering on Linux

2007, 27(8):  1858-1861. 

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The design and implementation of a Linux-based packet filter network traffic collection system named Packet Flow Collector (PFC) was proposed. Data packet filtering and merging were realized in kernel space, and memory sharing between user space and kernel space was implemented, so that PFC system made a breakthrough in the performance bottlenecks of traditional packet filtering network traffic collection system.

Campus-oriented stepwise-optimal hierarchical clustering algorithm of IP address

2007, 27(8):  1862-1864. 

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The cluster analysis of IP addresses can reveal useful knowledge for profiling of traffic flows and user behavior. However, the popular clustering algorithms were not applicable directly to IP addresses of the campus network traffic flows. The clusters which were generated by generic algorithms were inconsistent with the IP addresses partition and difficult to interpret. To overcome the shortcoming of the current algorithms which neglect the characteristics of IP addresses, a new algorithm which could effectively improve IP addresses clustering was proposed. Firstly, the initial clusters were got by adopting the longest prefix algorithm and the nearest neighbor clustering algorithm. Then the thought of stepwise-optimal hierarchical clustering was applied to merge the nearest groups of initial clusters. The similarity between initial clusters was determined by the longest prefix of IP addresses contained in these clusters. Finally, the algorithm automatically and meaningfully yielded clusters which were in accord with the characteristics of IP addresses on traffic flows. The results show that the proposed algorithm is accurate and effective in clustering IP addresses and robust to the input sequence of data.

Algorithm of 802.16 wireless packets scheduling based on traffic stream equilibrium

Lan FEI Chun-Jian PAN Hong-Yan TAN

2007, 27(8):  1865-1867. 

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According to the analysis of the four traffic streams from 802.16-2004 standard, and considering 802.16 network practical application, the packets scheduling algorithm which was based on operation streams balanced idea was put forward. The algorithm was simulated by using Matlab and compared with other algorithms. The simulation results indicate that the new algorithm can solve the priority problem and "starvation" instance better.

Design and implementation of energy module for WSN based on J-Sim

2007, 27(8):  1868-1870. 

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As the sensor network framework in J-Sim can not support energy consumption simulation, the designing idea in NS-2 was used for reference, and the energy module was extended in the existing sensor network framework considering the characteristics of J-Sim. Then two routing protocols (AODV、GPSR) were implemented on JSim. It shows that the improved sensor network framework can actually simulate Wireless Sensor Network (WSN) and obtain valuable simulation results.

Searching algorithm based on special interest group in P2P networks

2007, 27(8):  1871-1873. 

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From the perspective of implementation of a searching engine, flooding strategy, expending ring strategy, walker strategy and k-walker strategy were analyzed. According to the strategies, the idea of "small world" was adopted, and then a searching algorithm based on special interest group in Peer-to-Peer networks was proposed. The key idea of the algorithm was to change the role of network nodes from passive information providers to active servers for enquiries. In other words, the role of network nodes was changed from an information provider to an inquiry guider. Each node not only provided the required information for enquiries, but also led enquiries to nodes with same interests using the address book of special interest group. Therefore, the searching process could be speeded up, and the load of network could be reduced.

Reducing the peak-to-average power ratio of OFDM System by union algorithm

2007, 27(8):  1874-1876. 

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Methods of reducing the Peak-to-Average-Power Ratio (PAR) of the Orthogonal Frequency Dixision Multiplexing (OFDM) system have their advantages and disadvantages. In many cases, only using one of them can not achieve the desired effect of reducing or can achieve the desired effect but at the price of large performance loss on certain aspect. In view of such a situation, a joint algorithm named PTS-Clipping algorithm was given based on the complementarity between the PTS and impulse cancellation. Firstly, the algorithm used PTS to process OFDM signal to reduce PAR, then the result was further processed by impulse cancellation to further reduce PAR. As long as the two methods of reducing the PAR level were selected properly, it could reduce PAP and the computational complexity, and not have too much noise. Simulations have proved the validity of the proposed method.

Research of SIP Internet based on P2P

GuiLin LI

2007, 27(8):  1877-1880. 

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A hierarchical P2P-SIP architecture was proposed based on the features of the existing Peer-to-Peer (P2P) applications and Session Initiation Protocol (SIP). Implementation mechanism of the node was introduced in details. The traditioanl P2P technology was used to improve the reliability and selforganization of SIP network, and the interworking problem among the heterogeneous overlays was resolved.

Information security

Optimistic fair exchange protocol suitable for P2P network

Yang ZHAO Zhi-Guang QIN Tian LAN Jia-Hao WANG

2007, 27(8):  1881-1883. 

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According to the characteristics of P2P network, an optimistic fair exchange protocol was proposed, which was suitable for P2P network. Trusted Third Party (TTP) in traditional fair exchange protocols was substituted by a distributed temporary node set in this protocol, which effectively reduced the dependency on the honesty of TTP and the reliability of communication channel. The protocol can provide full fairness and security guarantee under the condition that at least 2/3 nodes in the temporary node set are honest.

Detecting DDoS attacks based on multi-stream combined HMM in sourceend network

2007, 27(8):  1884-1887. 

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A new approach for DDoS attacks detection was proposed in source-end network. This approach used Multi-stream Combined Hidden Markov Model (MCHMM) for integrating multi-features simultaneously. The multi-features included the S-D-P feature, TCP header control flags, and IP header ID field. Experiments show that the approach effectively reduces falsepositive rate and falsenegative rate, and detection precision of MC-HMM based on multiple detection features is clearly higher than that of the algorithms based on single-feature.

New colour image encryption algorithm based on high-dimension chaotic system

han feng-ying

2007, 27(8):  1888-1890. 

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According to the characteristic of higher secrecy of high-dimension chaotic system, a new colour image encryption algorithm based on unified chaotic system and general cat maps was proposed. Firstly, tricolor scrambling transformation was realized respectively in space domain by using the general cat maps. Then the three chaotic sequences of unified chaotic system were adopted to realize the tricolor Substitution transformation pixel by pixel. The results demonstrate that the algorithm has good properties of confusion and diffusion. The key space is large enough to resist the brute-force attack. For the encrypted image the distribution of pixel-values has a random-like behavior and the values of adjacent pixels satisfy zero correlation, showing that the proposed scheme is of high security.

Combined image encryption algorithm based on diffusion mapped disorder and hyperchaotic systems

Lian-xi HONG Chuan-mu Li Ming-xi LU

2007, 27(8):  1891-1894. 

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A combined image encryption algorithm was presented. The algorithm combined linear diffusion approach with Arnold mapped to disorder the image, and hyperchaotic sequences was used to encrypt the image. The mapped matrix and diffusion matrix were made up of chaotic sequences that were produced by the Logistic dynamic system, and they were used for disordering the color image to produce a disordered image on different bit planes to disorder the pixels. The disordered image was encrypted by means of the hyperchaotic sequences that were produced by the Chens system. The algorithm is simple and able to resist a variety of attacks, and can be easily implemented by hardware.

Chaos-based algorithm for image encryption in wavelet domain

2007, 27(8):  1895-1897. 

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The image encryption technology adapted to JPEG2000 standard was studied. A chaotic map based on Chebychev polynomial was proposed at first, and its statistic characteristics were analyzed. To accomplish a controllable visual effect of encrypted image, a quality control model was presented, and on the basis of which a chaoticmapbased image encryption method was constructed in wavelet domain. The security and efficiency of the algorithm were also analyzed. Experimental results prove that the algorithm is reliable, secure and efficient, and is practical to JPSEC.

Forward secure designated-verifier proxy signature scheme

2007, 27(8):  1898-1900. 

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As the existing designated-verifier proxy signature can not provide forward-security, so a forward secure designated-verifier proxy signature scheme was proposed by applying the concept of forward security to the designatedverifier proxy signature, based on the difficulty of solving discrete logarithm problems and the strong RSA assumption. In the scheme, proxy signature is forward secure, even if an adversary has gotten the current proxy signers' key, it could not forge proxy signature pertaining to the past, that is, previous generated proxy signature still remains valid.

Key pre-distribution scheme based on chaos in wireless sensor network

Nan Zhang Jianhua Zhang Jianying Chen Wenrong Tan Guo Zhao

2007, 27(8):  1901-1903. 

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To increase the security of Wireless Sensor Network (WSN), reduce the energy consumption and prolong the lifecycle of the system, a chaos scheme of key pre-distribution was put forward. In this scheme, the ergodicity of chaos was used to avoid the key of being decrypted, and chaos initial value sensitivity was used to ensure the key could be altered safely in communications. The analysis shows that the scheme can provide larger key space and the cost in communication and computation are smaller, thus it has stronger practicality.

Key pre-distribution scheme for wireless sensor networks based on Hash function

2007, 27(8):  1904-1906. 

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Key distribution plays a fundamental role in Wireless Sensor Networks (WSN). A key pre-distributing protocol based on Hash function was proposed, which extended the ideas of the probabilistic key pre-distribution scheme put forward by Echenaue and Gligor. In this scheme, some of the pre-distribution keys in the nodes were computed by Hash function. With the advantage of oneway Hash function, this scheme could enhance the ability of network to resist attacks. Compared with other schemes, this one has less computing overhead and higher security performance, which is more suitable for WSN.

Study on index system in network situation awareness

Wang Juan fengli zhang Chong Fu Lisha Chen

2007, 27(8):  1907-1909. 

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The development of the situation awareness in the world was introduced, and then the 25 indexes from security assessment and macro-network research were defined. And an index system of assessment from many data sources was designed. The use of index system in the assessment, prediction and visualization subsystems was presented. The index system covers a wide range of organizations with a reasonable organization and easily expandable features, and it can also be used in network security assessment and macro-network research.

IDS alert verification based on multi-source security information

2007, 27(8):  1910-1912. 

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Due to the design flaws and the ignorance of the target system's information, there exist several shortages in the current intrusion detection systems, such as alert overload and high false alarm rate. To solve these problems, based on the analysis of the current alert verification algorithms, a new alert verification algorithm has been presented in this paper. By utilizing the multi source security information including vulnerability information, system security log and the system state inspection information, the raw IDS alert information generated by the intrusion detection system can be verified and filtered according to the verification algorithm. Experimental results have demonstrated the effectiveness of the verification algorithm.

Secure threshold multi-secret sharing scheme based on special difference equation

Yanshuo Zhang Zhuojun Liu

2007, 27(8):  1913-1914. 

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A multi-secret threshold secret sharing scheme was introduced. Through one process of secret sharing, any secret sharing could be achieved, and participants share a secret and the length is only a secret length. Meanwhile, considering such programs threshold of safety, a secure threshold multi-secret sharing scheme based on special difference equation was given. Analysis shows that the given threshold secret sharing scheme has the information rate of 1/2, and for fraud prevention is unconditionally safe.

Verification method of security protocols based on correlation rules

2007, 27(8):  1915-1918. 

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An approach for the formal analysis of security protocols based on the correlation rules was proposed. The character of correlation of protocols was pictured from three aspects: the correlation of authentication between principals, the correlation between messages and within the messages. The verification method was presented based on the above correlation property, which had been used to verify the Woo and Lam authentication Protocol in reverse analysis. Some known attack paths were derived successfully, and made these known attack paths can be derived from this method in unity, and also discovered an unknown attack path. The method provides a new perspective in the formal analysis of the protocols.

Improved attack-resist trust metric model for public key certification

2007, 27(8):  1919-1921. 

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From the concept of trust and confidence related characteristics, the reason of raising the trust metric was introduced. Several trust metric models were recommended, and their characteristics and commonness were analyzed. The study focused on the Levien trust metric model and its shortcomings, and a modified node trust metric model was proposed from the perspective of the attacker. The new model, based on the structure of Levin's model, is used for computing attackers' capacities for a successful attack. It imports a descending factor of trust transmission to measure the trust metric of each node synthetically, and gives a better way to improve trust metrics through analysis.

Bi-watermarking algorithm for H.264/AVC low bit-rate video stream

2007, 27(8):  1922-1925. 

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Noticing the new features of the H.264/AVC video coding standard, through the research into the coding of the DCT coefficients of I-frames and the processing of the motion estimate of P-frames, a new bi-watermarking algorithm that can realize the copyright protection and the integrality authentication jointly was proposed. Simulation results show that the video stream has a good rate-distortion balance by using the coding control technique of Lagrangian optimization; the robust watermark embedded has good immunity to some attacks such as requantization, frames-editing and so on, and the fragile watermark embedded is very sensitive to various common attacks. This algorithm need not decode to the video bit stream entirely, and it realizes the blind detection of bi-watermarking, which can achieve the requirement of the random detection in real-time.

Efficient scalar multiplication algorithm against SCA for Koblitz curve cryptosystems

2007, 27(8):  1926-1928. 

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Analysis of how to transform Doubling attack to attack Koblitz curve of the scalar multiplication was given. A randomized method for input points by using point halving was proposed, which was integrated with Koblitz curve of fixed window algorithm, to resist the side channel attack. The analysis demonstrates that the method can not only resist Simple Power Analysis (SPA), Differential Power Analysis (DPA), Refined Differential Power Analysis (RPA), Zero-value Power Attack (ZPA) and Doubling attack, but also has efficient and practical significance.

Mobile security service system based on security level negotiation

Wei-Zhong QIAN Chen-xuan GUO Jian-yong CHEN

2007, 27(8):  1929-1930. 

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The different security requirements of applications on mobile communication environment were introduced, and the security policy and its structure were designed. On the basis of the policy, a model of mobile security service system was proposed, and the security level negotiation between network elements in different security levels was presented. The research production can provide a solution for allocating security services based on user requirements and be a technology guarantee for mobile communication operator to implement valueadded security service.

Relational database watermark method based on user restraint

2007, 27(8):  1931-1934. 

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A new method that digital watermarking information was embedded in numerical attribute's Least Significant Bit （LSB） was put forward in view of the existing watermark algorithm's insufficiency. After sieving attributes that could embed watermarking information and dividing these attributes into some equal subsets that would be further sieved based on the binding defined by the database owner， watermark 0 or 1 was embedded into each sieved subset. The watermark detection algorithm based on the central limit theorem can test watermarking information accurately. In the end， the simulation experiment using SQL Server verified the validity of algorithm in practical application.

Survey of trust and reputation mechanism on P2P network

2007, 27(8):  1935-1938. 

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The concepts and contents of trust and reputation mechanism on peer-to-peer network were described and analyzed，and the current research progress in the field was reviewed. Moreover, the problems related to the research on the trust and reputation mechanism on P2P networks were proposed, and the solutions to the key problems were also suggested.

Design of CPK authentication system and implementation of its key generation

Wen DENG

2007, 27(8):  1939-1941. 

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The design of an identification authentication system was introduced based on Combined Public Key (CPK), and a combination of mapping algorithm and key management of multiscope was given. Based on the principle of CPK, the scale of the key management and independent thirdparty authentication were achieved by using combination of mapping algorithm. The method will be valuable for the other authentication system based on CPK.

Unknown virus detection based on API sequence and support vector machine

2007, 27(8):  1942-1943. 

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Based on the analysis of Windows API calling sequences of PE files, a method for unknown virus detection in Windows platform was proposed by Support Vector Machine (SVM). The experimental results demonstrate the robustness and intelligence of the BK-50 system in detecting unkonwn virus.

Artificial intelligence

Evolutionary substructure discovery algorithm based on individuals with state backtracking

Xin-gong CHANG Ji-song KOU Ming-qiang LI

2007, 27(8):  1944-1947. 

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In order to overcome the limit that the greedy search, which is often used by some prevalent graphical data mining systems, may often end up by providing sub-optimal solutions, an evolutionary algorithm was imported to perform data mining on databases represented as graphs. In order to handle the subgraph isomorphism problem, the concept of individuals with state backtracking was proposed, where the state information of some potential individuals produced during the evolution were preserved, which contributed to the design of genetic operators. A new diversity keeping scheme was also proposed to preserve the diversity both from the composition of population and the way of generation of individuals. In addition, removing the individuals not potential in current population reduced the search space greatly. Experimental results show that these measures enhance the searching capability of the algorithm and hence increase both the efficiency of the algorithm and the quality of solutions.

Algorithm extended to an estimation of distribution algorithm based on linkage detection and factorization

2007, 27(8):  1948-4951. 

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Genetic Algorithm (GA) has been found to be lack of effectiveness in solving optimization problems where there is a large amount of interaction between variables, one approach to solve this problem is Estimation of Distribution Algorithms (EDA). Factorized distribution algorithm is an EDA that uses approximation of higher-order interaction, and it uses a factorization of the Boltzmann distribution for the generation of new solutions. A new algorithm which finds the optimum with high probability based on the linkage detection and factorization was given. The algorithm can solve the problems which EDA may have difficulties to deal with. Experimental results prove that the new algorithm is feasible and effective.

Method to identify the random-like property of chaotic sequences

2007, 27(8):  1952-1954. 

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A method of identifying the strength of random-like property of chaotic sequence was proposed with the rate of exhaustive history in sequence production. The step number of exhaustive history in producing process of a sequence was calculated first, and then the rate of exhaustive history was gotten according to the length of the sequence. The method does not need phase space construction, and is adapted to discrete chaotic system and continual chaotic system. It is more significant in digital chaos secret communication. Simulation result shows that the method is valid to identify the strength of random-like property of different chaotic sequences.

Support vector regression based on manifold regularization and its application

2007, 27(8):  1955-1958. 

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Based on the theory of manifold regularization, a new algorithm about semi-supervised learning for the problem of regression was proposed. The algorithm was deduced by the connection between the regularization term on the manifold and the classical regularization term. Using the result of support vector regression, the algorithm not only solves the problem about semi-supervised learning but also improves generalization capability. Numerical experimental results show that the algorithm enhances generalization capability and is strongly robust to noise, and has higher learning precision compared to support vector regression.

Robust ISOMAP insensitive to singular value

Lai WEI Shoujue WANG Feifei XU

2007, 27(8):  1959-1960. 

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ISOAMP is a classical nonlinear dimensionality reduction algorithm. It is effective to discover the low-dimensional manifold in a high-dimensional data space. But the algorithm is very sensitive to the noises and singular value. Principal Component Analysis with robustness (Robust PCA) was used to detect singular points, and the singularity was also appropriately treated to reduce the ISOMAP's sensitivity to it. The proposed algorithm is intuitive and easy to understand, the results of the experiment prove that it is robust, and can maintain the overall structure of data with more singular points.

Selection of SVM parameters using chaotic series and its application in handwriting verification

2007, 27(8):  1961-1963. 

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In order to find the optimization compound of Support Vector Machine (SVM) parameters, that is penalty factor and nuclear factor, and help to identify the handwriting image, a parameter searching algorithm based on chaotic sequence was proposed to determine the SVM parameters automatically. Compared with the grid search and two-line search, the proposed algorithm is much simpler and easier to be implemented, which makes SVM has better outreach capacity. Classification experiment on 10 people handwriting gray-scale images prove that the proposed algorithm has higher classification rate and significantly reduce the number of training SVM.

Parallel algorithm of attribute reduction in rough set

2007, 27(8):  1964-1966. 

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A new parallel algorithm based on rough set was proposed after introducing the concepts of distinguishable relation and distinguishable matrix. The algorithm divided the system into several sub-systems, and then the evaluation index was used for the parallel computing of the sub-systems. Finally, the original system's reduction was got based on the part reduction results of the sub-system. The proposed algorithm has good performance in spatio-temporal, and it is good at dealing with the huge volume of data.

Adaptive genetic algorithm based on distance measurement

Hong-Lian SHEN Guo-Li ZHANG Zhen-Tao LI Shu-Ling WANG Gui-Bo NI

2007, 27(8):  1967-1969. 

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In order to increase convergence probability and evolving speed of the adaptive genetic annealing algorithm based on distance measurement, an improved algorithm was proposed. The algorithm defined the mutation probability according to distance density and fitness, adopted improved crossover and simulated annealing operation. In addition, when population tended to be uniform, it reserved the best individual and reproduced other individuals. Applying the improved real-coded genetic algorithm based on distance measurement to function optimization problem with boundary constraints, the simulative results show that the improved algorithm is more effective in realizing the high convergence probability and rapid evolving speed.

General model for dynamic contract net protocol based on object-oriented Petri net

Dan LI Li CHEN Gong-li LI

2007, 27(8):  1970-1972. 

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The traditional contract net protocol model which works on bids invitation between a manager Agent and contractor Agents can successfully realize the cooperation and complete the goal task among Agents. But it also faces many problems such as the high traffic and weak general availability. Therefore, the ObjectOriented Petri net and the concept of object Agent were used to describe the dynamic contract net protocol. The analysis shows that this new model is live, concurrent and can lighten the traffic and enhance the general availability.

Efficient beam search decoder for phrase-based statistical machine translation

Yi Luo Miao Li Jian Zhang

2007, 27(8):  1973-1975. 

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An efficient beam search decoder for phrase-based statistical machine translation was described. The efficiency of search algorithm is the key to decoding process. After introducing the conventional beam search decoding algorithm, some efficiency improving measures were proposed. Dynamic pruning strategy enhanced the accuracy of pruning by improving that the original fixed pruning had not enough response to the current situation of search. Pre-pruning strategy was used to limit the poor sprawl, reduce unnecessary expansion and improve search speed. A rapid reordering constrains strategy was presented based on the research of the current major reordering constrains. In addition, the domain term always has the only translation, so a special process approach was put forward to improve the accuracy of the translation. Comparative analysis of the experimental results proves the effectiveness of the algorithm.

Articles

Real-time clustering algorithm for multiple data streams

2007, 27(8):  1976-1979. 

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To overcome the imbalance between clustering quality and efficiency in current multiple data streams clustering algorithms, a clustering algorithm based on correlation coefficient was proposed. The algorithm can dynamically discover the clusters in the data streams over a fixed time period. The attenuation coefficient was introduced to improve the performance of clustering and the correlation coefficient was used to measure the similarity between data streams. In the algorithm, the time horizon was divided into several equal segments and statistical information was computed for stream data in each time segment. The algorithm can modify the clustering structure according to the statistical information in real time. Experimental results show that the algorithm has higher efficiency, clustering quality and stability than other methods.

Fast low-cost shortest path tree algorithm based on ordinal circularly double linked list

2007, 27(8):  1980-1983. 

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Low-cost shortest path tree is a commonly-used multicast tree type. On the foundation of the Fast Low-cost Shortest Path Tree (FLSPT) algorithm, the ordinal circularly linked list was selected as the calculating and saving center of sequence Q of nodes which were waiting for development. The fast low-cost shortest path tree algorithm based on ordinal circularly double linked list named Fast Low-cost Shortest Path Tree (DKFLSPT) was put forward. The shortest path tree constructed by DKFLSPT algorithm is the same as that constructed by FLSPT algorithm, making use of the part principle of ordinal circularly double linked list to improve the search procedure which can get the shortest path of nodes. The imitated experiment of random network indicates that the efficiency of DKFLSPT algorithm can be raised by 19%.

Rule-driven exception handling approach for Web Service composition

Ping ZOU

2007, 27(8):  1984-1986. 

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A rule-driven exception handling model for Web service composition was proposed. The semantic of the model was specified in detail too. The rule in the model is based on event, activity state and meta-process. Meta-process is invoked by relevant rules as controlling and coordinating mechanism for base processes. The proposed model can not only be used for failure recovery, but also be used for more complex situations such as process modification. The advantages of this approach are modularity, extensibility and adaptability.

Analysis of building procedure of parallel environment with P4

2007, 27(8):  1987-1990. 

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In the environment of workstation cluster which is configured with Linux, the initialization process of the P4 (Portable Programs for Parallel Processors) which supports the parallel programming was studied. The two parts of the creation of processes and the establishment of communication were analyzed in depth, and the use of the main data structure involved in the source code was analyzed in detail. It has a certain reference value to research and development of parallel programming tool.

SCV based random instruction generation tool for MIPS instruction set

Bing Tian

2007, 27(8):  1991-1993. 

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A SCV-based random instruction generation tool used for generation of MIPS instructions in a system level modeling and simulation environment of SystemC was introduced. The tool consisted of two kinds of generation mode, the static mode and the dynamic mode. The problems in random instruction generation, such as data access violation, branch/jump violation and others, were solved. Additionally, a method with respect to the verification of pipeline conflict was provided.

Research of QoS model for component system in real-time embedded environments

2007, 27(8):  1994-1996. 

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The introduction of component-based development into real-time embedded platforms is desirable to adapt themselves to the heterogeneity of embedded applications, and it is necessary to satisfy the requirement of software development efficiency. Due to the dynamic resource requesting of real-time embedded platforms and the overall administrative features of system resources, the adaptation mechanism in application level is not the final solution, furthermore the additional QoS managing policy plugged into the current component framework is requisite. Thus, a CCM component-oriented QoS model was proposed, which could adapt itself to the fluctuating component states proactively. At the same time, hierarchy QoS transformer in this QoS Model can simplify the configuration of service QoS parameters greatly.

Algorithm of Web Services query based on bottleneck cost

2007, 27(8):  1997-2000. 

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Web Service has become a standard method of sharing data and functionality among loosely-coupled systems. An algorithm based on bottleneck cost metric to arrange a query's Web service calls in optimal fashion was proposed. Optimal exploits parallelism among Web services was used to minimize the query's total running time. The optimal plan can be used in the presence of arbitrary precedence constraints among Web services. Compared with other optimal decisions, the experimental results prove the validity of the algorithm.

Graphics and image processing

Research and implementation of enhancement algorithm for low-illumination image

2007, 27(8):  2001-2003. 

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Aiming at the darkness and low contrast of low illumination image, a low illumination image enhancement method, combining improved Histogram equalization and improved local contrast enhancement, was designed, which satisfied the needs of adjusting dynamic range and enhancing local contrast. Experiments show that the method will give observer a clearer global image with enough local contrast details in processing a low illumination image.

Multisource image classification method based on information fusion in remote sensing

Chunping Liu

2007, 27(8):  2004-2006. 

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A new classification and fusion method for multi-source of remote sensing images was put forward based on the D-S evidence theory. Select the interesting region of class by experience and obtain basic probability assignment function by extracting feature at first, then combine multi-source image to be grouped with Dempster's orthogonal rule to get the result of classification. Experiments show that the proposed method is superior to the K-mean. The uncertainty in classification is effectively decreased, as well as the classification accuracy is improved.

Image fusion based on monoscale ridgelet transform

2007, 27(8):  2007-2010. 

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Image fusion can be considered as a process to analyze, abstract and synthesize singularities of 2-D functions. The upper bound of approximation error of the monoscale ridgelet transform is lower than that of the wavelet transform. As a result, the energy of the coefficients correlated with the edges and the corners in images is more compact. The relation between the effect of fusion methods based on the transform domain and the rate of approximation of the transform was discussed. A new image fusion method based on the monoscale ridgelet transform was put forward. In experiments, the proposed method was compared with the algorithms based on the Laplacian pyramid, the wavelet transform, and other existing methods. Results show that the proposed method outperforms the others, and exploit the application scope of the monoscale ridgelet transform.

Flow field visualization method based on particle texture blending

2007, 27(8):  2011-2013. 

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Texture based visualization methods can describe the whole structure of the flow field, but traditional methods are always time consuming and the visualization image has low contrast. In order to improve the efficiency of the whole visualization process, a new particle texture blending based flow field visualization method was presented. Firstly a set of random noise images were given as original particle distribution images. Then particle trace image would be generated by blending the original particle distribution image with distorted flow data grid. Finally, a series of particle trace images compose the dynamic display of flow field. This method is independent from flow data, having fast rendering rate and high contrast output image. The parameters have obvious physical meaning, and different vision effect visualization output results are derived from different parameters combination. This method can take full advantage of the graphic card accelerator, and has successful application in the dynamic visualization of the flow data in crystal growth experiment during task research work.

Improvement on adaptive mixture Gaussian background model

Quan-min LI Yun-chu ZHANG

2007, 27(8):  2014-2017. 

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To improve the quality of motion segmentation, the background reconstruction and foreground mergence time control mechanism were incorporated into the adaptive mixture Gaussian background model. The background reconstruction algorithm constructed a static background image from a video sequence which contained moving objects in the scene, and then the static background image was used to initialize the background model. The foreground mergence time control mechanism was introduced to make the foreground mergence time adjustable and independent of the model's learning rate. The experimental results prove the effectiveness of the algorithm.

Feature surface recognition in reverse engineering

Rong HE

2007, 27(8):  2018-2020. 

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An algorithm of feature surface recognition based on quadric surface fitting and geometry property was presented. Firstly, using quadric surface to fit with given surface and calculate the error metric to identify free surface and general quadric surface. Then, compute geometry property of each point on Gaussian sphere and curvature coordinate. The distribution would identify each kind of quadric surface and blend surface. In order to improve the efficiency and practicability, this algorithm calculated approximation distance from point to surface and make priority to identify planes. This algorithm is easy to recognize plane, cylinder, cone, sphere, blend surface and free surface.

Polymorphisms single template masking for edge detection based on clustering algorithm

2007, 27(8):  2021-2024. 

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A polymorphisms single template masking for edge detection algorithm based on clustering was proposed, which could dynamically estimate the edge location of the neighborhood. The algorithm would set the weight parameters on the template by evaluating the position of the possible edge, which would give a more precise result. It made it possible to reduce the noise but keep a higher resolution by debarring the fake edge according to its continuity. Experimental results prove the effectiveness of this algorithm.

Method for noises removel based on PDE

xiong Bao-Ping

2007, 27(8):  2025-2026. 

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Nonlinear diffusion filter based on Partial Differential Equation (PDE) is good at removing Gauss noises, but do not well at pulse noises. From the diffusion coefficient of Perona & Malik model, the function nature was analyzed. By changing the form of the threshold value in diffusion function, it can get rid of the noises from image while preserving edges better, and overcome the contradictions between keeping edge and eliminating noises.

Nonuniform simplification of cloud data based on octree

Lei Ma Guo-Hua Peng Dong-Fang Geng

2007, 27(8):  2027-2029. 

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An efficient nonuniform simplification algorithm was proposed. At first, the minimum cube box of the data sets was gained, and it was divided into eight cubes with employment of octree. Then surface variation of local discrete surface and the number of points in nonempty cubes were calculated, and these cubes were divided continually or not according to the two user-specified thresholds. In the end, one point was reserved for each leaf cube. Practical examples show that the efficient method can exactly retain geometric characteristics of original dates and be applicable for complex cloud data.

Polygonal approximation of curves using binary quantum-behaved particle swarm optimization

2007, 27(8):  2030-2032. 

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Quantum-behaved Particle Swarm Optimization (QPSO) algorithm was proposed to discrete binary search space. To design Binary QPSO, position vector and distance between two positions were redefined, and the iterative equation of QPSO was adjusted to binary search space. A new polygonal approximation approach based on the Binary QPSO was also presented, having solved the restriction of the search bound in BPSO. Using two common benchmark curves to test, and the results show that the algorithm accelerate the convergence rate, and get fewer points in the polygon at the same tolerance error and the same number of iterations.

Design and implementation of the fast ray tracing based on GPU

2007, 27(8):  2033-2035. 

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Light tracking algorithm based on GPU with the stream architecture was designed and implemented. Meanwhile, to avoid the overhead in stack operation of the traditional KD-Tree when traversing, a KD-Tree structure based on threaded binary tree was used to organize scene. The method is superior to the use of traditional KD-Tree and uniform split structure to accelerate traversing in organizing complex scenes, and the rapid tracking rendering of light was achieved in ordinary PC.

Intelligence perception

Mathematical formula extraction method from printed document based on fuzzy classification

Xue-dong TIAN Nan HAO

2007, 27(8):  2036-2037. 

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Process of mathematical formula extraction from printed document is a basal step. Most of the available extraction methods assume that the regions containing mathematical formulas are known. An algorithm to extract isolated mathematical formulas by introducing fuzzy classification theory was described. Six features, such as degree of irregularity，width-to-height ratio and density ect, were selected from lots of data that came from training samples counted and analyzed, thereby the rule of fuzzy classification was built to handle isolated mathematical formula lines, text lines and title lines, so mathematical formula extraction was realized. The experimental results indicate that this method could obtain favorable veracity and good robustness.

Face feature extraction method based on CGA and ICA

2007, 27(8):  2038-2040. 

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Independent Component Analysis (ICA) was presented as an efficient face feature extraction method. In order to improve the ability of ICA, a Genetic Algorithm （GA) was used to select optimal Independent Components (ICs) and reconstruct new feature space. Projecting image into new feature space can get the projecting coefficients as its feature. In order to avoid the initial populations asymmetry and make the search more globaloriented, the chaos was applied to the initial population of GA (CGA). Experimental results show that the CGAICA method performs better than ICA method.

Face illumination compensation based on Armlets

2007, 27(8):  2041-2043. 

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A new illumination compensation method for face recognition under nonuniform illumination conditions was presented. The method calculated 2-dimensional Armlets (analysis-ready multiwavelets) transform for face illumination compensation in logarithm domain, and then conducted face recognition experiment directly in logarithm domain. The proposed approach was compared with other illumination compensation methods on Yale B face database. The experimental results show that the average error rate of the proposed approach is only 0.18%, which is superior to that of all the existing methods.

Recognition of radar target based on adaptive feature subspace using range profile

2007, 27(8):  2044-2046. 

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Aiming at the shortcoming of general statistical feature subspace for range profile recognition in radar target, an adaptive feature subspace approach was proposed. When the number of subspace's dimension or the number of target classes was changed, the adaptive feature subspace could be easily obtained by iteration. Compared with general statistical feature subspace, less operation was needed in forming the adaptive feature subspace. The simulated experimental results of three targets and four targets demonstrate the efficiency of the proposed approach.

New segmentation algorithm on gait image sequences

Jun GUO Yu-mei WEN Ping LI Bo YE Xiao LI

2007, 27(8):  2047-2050. 

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In gait recognition, the effective extraction of human contours from gait image sequences is of great concern to subsequent processes including feature extraction, object classification and object recognition. A new moving object segmentation algorithm was proposed. A new block-matching motion estimation algorithm was adopted at first. Then the watershed algorithm was used to divide current image into closed and non-overlapping regions. Finally, affine parameters model was utilized to merge the separate regions. The experiments on the CMU Mobo data set prove that this algorithm can effectively extract human contours and eventually improve the performance of gait recognition.

Application of variable frame length and frame rate in speaker verification system

2007, 27(8):  2051-2052. 

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A new method for extracting MelFrequency Ceptral Coefficients (MFCC) was proposed from the perspective of variable frame length and frame rate. The proposed method restricted the frame length and frame shift to multiples of pitch period, called pitch synchronous algorithm; then removed some frames where the acoustic feature changed slowly to decrease the frame rate according to the principle of variable frame rate algorithm. With speaker verification experiments on NIST 99 speaker recognition evaluation, the new approach not only improves the system performance but also decreases frame rate, which means saving the storage space of feature files.

Adaptive α-β filter algorithm

2007, 27(8):  2053-2055. 

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Data processing system is the key of phased array radar search and multi-target tracking, and the tracking filter algorithm will directly determine the merits of the system's performance. Adaptive α-β filter algorithm was introduced, and then it was compared to LSR filter algorithm and Kalman filter algorithm, the mean square deviation of distance, position, speed and direction of these algorithms on the flight line was analyzed to discuss the specific use of the three filters in straight-line flight and about-ship straight-line flight. The experimental results prove that the adaptiveα-β filter algorithm has good effect in straight-line with small computational complexity, and it is in favor of modeling and simulation.

Typical applications

Monocular vision-based vehicle collision warning system

2007, 27(8):  2056-2058. 

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Monocular vision-based vehicle collision warning system can detect the front vehicle and estimate the distance between the host vehicle and the front vehicle，by providing warning mechanism it can protect drivers from danger in time. Lane detection and vehicle recognition are the major two problems in need to be solved in this research. Lane markings were detected using edge distribution function (EDF) and vehicle detection was achieved by using features, such as texture of underneath and symmetry property. The distance to front vehicle was then estimated from relation between image coordinate system and world coordinate system. The experimental results show that the proposed method can detect lane markings efficiently and the estimated distance is well provided to drivers.

New micro-payment protocol for mobile commerce

2007, 27(8):  2059-2061. 

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An authentication scheme for mobile commerce based on self-renewal hash chains scheme (SRHC) was proposed, and a micropayment protocol was designed. The protocol is suitable for micropayment such as information commodity between a mobile user and a fixed service provider. The analysis results show that the proposed scheme needs less interaction and no digital signature to authenticate mobile user in the foremost time, as well as session keys are negotiated efficiently. The proposed protocol not only has better security, efficiency and fairness, but also solves the problems of malicious over-spending and time limit.

Efficient real-time processing for readonlytransaction in mobile broadcast environments

Xiang-Dong LEI Yue-Long ZHAO Song-Qiao CHEN Xiao-Li YUAN

2007, 27(8):  2062-2065. 

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The new method processing mobile real-time read-only transactions was proposed in mobile broadcast environments. Various multiversion broadcast disk organizations were introduced. Mobile read-only transactions could be committed with no-blocking by multiversion mechanism. The conflicts between mobile read-only and mobile update transactions could be eliminated by optimistic method. To avoid unnecessary restarts of transactions, multiversion dynamic adjustment of serialization order was adopted. If a readonly transaction passed all the backward validation in MH, it could be committed without contacting with the server. Response time of mobile read-only transactions was greatly reduced. The results of simulation experiment show that the new method performs better than other protocols.

Kernel clustering algorithm with the constraint about the image segmentation in the electronic patient record

2007, 27(8):  2066-2068. 

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An improved kernel clustering algorithm based on constraints was proposed, which was used to resolve the problem of the image segmentation in the electronic patient record. The proposed algorithm was designed to retouch the images before they were segmented to improve the image segmentation. The experiment adopted the kernel clustering algorithm in MRI image segmentations, and the results show that the proposed algorithm, compared with classical algorithm, is more effective in solving the inherent problems in the electronic patient record images including noises and intensity inhomogeneities, etc. And accordingly the proposed algorithms are robust and can achieve better image segmentation results.

Query expansion based on chaotic neural network

2007, 27(8):  2069-2071. 

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To resolve the problem that general information retrieval models need exact match, a new query expansion was provided. With strong memory, learning and association ability, the chaotic neural network was used to learn from users query operations. Then users initial query condition was expanded and reconstructed so that the different retrieval results could be acquired to satisfy the users query motivation. The experimental results prove that the new model has better performance than the traditional neural network information retrieval models.

Process model for e-government business processing

2007, 27(8):  2072-2076. 

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Currently, an e-government system usually supports the business processing by a process model. However, the existing business process models lack a certain flexibility and security. A business process model for the e-government business processing was proposed. The model separated business rules from process flows and related them in with a coupling mechanism. On the one hand, it makes the definition of process flows simple and supports their flexible changes; on the other hand, it makes the maintenance of business rules convenient and independent of the process flows, thus guaranteeing the security of the business processing. An application example of the model was given at last.

Checking consistency between drawings based on image invariant moments in wavelet domain

2007, 27(8):  2077-2080. 

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Checking consistency between the scanned drawing and the electronic drawing is required in the flow of electronic declaring. The approach of checking consistency between drawings in drawings audit system based on wavelet transform and image invariant moments was presented for solving this problem. Firstly, the scanned drawings were processed by affine transform in order to achieve image registration. Secondly, the scanned drawing and the electronic drawing were decomposed by wavelet transform, which could reduce the complexity of the computation. Finally, checking consistency between drawings could be completed using the traits of invariant moments, such as shift, rotation and scale invariant. The experimental results show that the proposed algorithm can well check the consistency between drawings.

Implementation of creative conception design system based on fractal

Yu-Lin SUN Hong LIU Xiao-Hui WANG

2007, 27(8):  2081-2083. 

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An approach to implement creative conception design system by using fractal was presented to improve the initial conception design process that used math function in the past. An example of architectural modeling creative design was given: swarms were initialized by fractal operations such as mergers and so on, and then calculated by evolution algorithm. Experiments indicate that the fractal approach is promising to develop creative conception design system.

Design and implementation of well test software by video image

2007, 27(8):  2084-2086. 

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A method of well test interpretation with video image was presented. According to the size of the object on the video image, the size of target in the well was calculated by using camera lens optics imaging principle. Based on the characteristics of the video image，the particular part of the image was binarized to separate oil and background, so analogous oil ratio in appointed depths could be calculated. First smoothing process was applied to the video images, and then the number of the oil holes in the appointed depths was calculated out by the edge detection of Gauss Laplace operator. The ellipse edge of the casting was revised to roundlike edge of vertical well axle based on geometric rectification technology.