20 April 2008, Volume 34 Issue 8
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Computer Engineering. 2008, 34(8): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2008.08.001Chaos defined in general in quantitative characteristics is not a strict definition. In this paper two new chaos functions are proposed and theoretical proof about chaos is finished based on a strict Devaney definition. Using composite chaotic system character, a composite chaos sequences cipher algorithm is designed, the map of which has uniform distribution function, and can produce balance nature series to 0-1 after being quantified. The unchanged probability of composite chaos makes ciphertext have a good random. As the sensitivity to initial condition and random nature to iterative function choice, key and plaintext and ciphertext form complex and sensitive nonlinear relations, and the correlation is very small. The leaking of ciphertext to key and plaintext information can be effectively prevented. Experimental results show that the system has a very high safety and the key space is expanded.
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Computer Engineering. 2008, 34(8): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2008.08.002Neighborhood Preserving Projections(NPP) is a method for unsupervised linear dimensionality reduction, which can preserve the local neighborhood structure on the data manifold. However, when NPP is applied to the classification tasks, it has some limitations such as ignorance of the class labels information. This paper proposes a novel subspace method named Supervised Neighborhood Preserving Projections(SNPP) for face recognition, in which local geometric relations are preserved according to prior class-label information. It gains a perfect approximation of face manifold and enhances its discriminant power in a feature space. Experiments on ORL face database demonstrate the effectiveness of the method.
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Computer Engineering. 2008, 34(8): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2008.08.003The paper proposes a modified q-recursive algorithm of fast computing Zernike moments. The method improves the efficiency of calculating Zernike moments by reducing the computational complexities of the Zernike polynomials and the Fourier functions of the kernel functions. In the first step, the q-recursive method, which avoids the factorial operations and the power series of radius involved in radial polynomials, is employed to compute the Zernike polynomials. In the second step, the image domain is divided into eight equal parts by four lines, which are x=0, y=0, x=y and x=-y. On computing Zernike moments, the kernel functions are merely calculated in one part. The function values of the other parts can be obtained by the symmetry property about the four lines of the kernel functions. It not only saves the storages for the kernel polynomials but also reduces the computation time. The performance of the algorithm is experimentally examined using a binary image, and it shows that the computational speed of Zernike moments has been substantially improved over the present methods.
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Computer Engineering. 2008, 34(8): 10-11. https://doi.org/10.3969/j.issn.1000-3428.2008.08.004This paper proposes a novel k-nearest neighbor searching algorithm. The coordinates of origninal point data sets are sorted along x, y and z axis individually. The position of desired point is computed in the sequence of rearranged points, from which it can obtain a dynamic grid where the k-nearest points are searched. Compared to the conventional bounding box-based k-nearest neighbor searching method, the scheme can overcome the drawback of the uncertainty of the amount of points with the bounding box space subdivision. A outstanding innovation of the method is arbitrarily increasing or decreasing the grid, according to the density of the point set. So the k-nearest neighbor can be calculated efficiently.
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Computer Engineering. 2008, 34(8): 12-14. https://doi.org/10.3969/j.issn.1000-3428.2008.08.005To study the security with known image of a chaotic stream image encryption algorithm, this paper gives the rule of information leakage by analyzing the property of the algorithm functions, and designs attack algorithm based on the rule. The equivalent key of the encryption algorithm can be found by attack algorithm, and the computing complexity of the attack is given. It is proved that the encryption algorithm is insecure for known-image attack.
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Computer Engineering. 2008, 34(8): 15-18. https://doi.org/10.3969/j.issn.1000-3428.2008.08.006Chirp signal used as watermarking can be hidden in the spatial domain of the host image, and the watermarking is detected blindly through the fractional Fourier transform in the transform domain. To enhance the robust performance of the algorithm, this paper analyzes the reasonable order of fractional operator for direct discrete Fourier transform method, and hides a Chirp signal into low frequency wavelet-domain. Experiments show that the improved blind watermarking detection algorithm is robuster than the algorithm which embedded watermarking into the special domain of the host image, and can detect the Chirp watermarking rapidly.
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Computer Engineering. 2008, 34(8): 19-21. https://doi.org/10.3969/j.issn.1000-3428.2008.08.007
Constraints are considered to be the principal motivation for Role-Based Access Control(RBAC). This paper analyzes XML based access control language XACML and points out some shortcomings of the XACML profile for RBAC. It provides role enablement authority to extend this profile, in this way, several kinds of constraints of RBAC such as separation of duty constraints and cardinality constraints can be enforced and implemented using XACML.
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Computer Engineering. 2008, 34(8): 25-28. https://doi.org/10.3969/j.issn.1000-3428.2008.08.009This paper presents a multi-way tree based multi-scale line structure for progressive transmission of vector data. By topological restraints, the structure maintains the consistent topological relations among the lines of different scales. The structure provides more efficient hierarchical data management by integrating the data of the same scale into one certain level node. And the order of the points in the original line is described by the relative order of points in the multi-scale line tree, so that it can restore the line in any scale, which also supports the edition of multi-scale line without rebuilding of the multi-scale structure. And the data in different scale are independent of each other, so that the data can be stored in different scale into different database table, which improves the first access efficiency.
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Computer Engineering. 2008, 34(8): 29-31. https://doi.org/10.3969/j.issn.1000-3428.2008.08.010The instruction system on the Web lacks the personalized teaching due to the simple digitalization. This paper proposes an ontology-driven intelligent knowledge navigation map. In the personalized, intelligent and autonomic learning system, users can customize the study content directly, and the agent grid platform can collect personalized information and build personalized study documents based on the users’ behaviors observations and evaluations, referring to the built knowledge ontology. It makes use of agent grid intelligent platform AGrIP to build an autonomic learning system and provides better knowledge services.
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Computer Engineering. 2008, 34(8): 32-34. https://doi.org/10.3969/j.issn.1000-3428.2008.08.011This paper proposes a kind of method that can preserve integrity constraints in data mapping, contrives a mechanism (DAPPIC) of generating constraints-preserving publishing rules. The key technique and design of the DAPPIC are summarized. The implementation and application of CoXML reveal that these techniques work well in practice.
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Computer Engineering. 2008, 34(8): 35-37. https://doi.org/10.3969/j.issn.1000-3428.2008.08.012This paper proposes an Ant Colony Algorithm based on Heuristic Mutation(ACAHM), combining with the advantage of the traditional Ant Colony Algorithm(ACA) and the genetic mutation algorithm. ACA is used to find a globally near optimal solution, and then it is optimized by the heuristic mutation. The optimized route information is passed to the next generation with the pheromone to quickly get a globally optimal solution. Simulation results for solving the Traveling Salesman Problem(TSP) show that ACAHM is superior to other congeneric algorithms in terms of solution quality and computation speed.
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Computer Engineering. 2008, 34(8): 38-40. https://doi.org/10.3969/j.issn.1000-3428.2008.08.013For the characters of distribution, heterogeneity and dynamic of biological data, a resolution of the service system for bioinformatics technology is presented, and an approach of biological data integration based on Gene Ontology(GO) is proposed in order to realize biological semantic integration. Semi-structured incremental updating method to standardize biological metadata with MD5 algorithm to improve the updating efficiency is designed, which resolves the data sharing and the efficiency of data management in biological data warehouse.
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Computer Engineering. 2008, 34(8): 41-43. https://doi.org/10.3969/j.issn.1000-3428.2008.08.014SCSI is a mature protocol and used widely in storage system. This paper presents an implementation of SCSI target based on SCSI stream command set. This target receives stream command and converts it to block command. A cache mechanism is employed for better transfer performance. Some experiments on the influence of cache are carried out and the results are analyzed.
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Computer Engineering. 2008, 34(8): 44-46. https://doi.org/10.3969/j.issn.1000-3428.2008.08.015Non-Homogeneous Poisson Process Software Reliability Growth Models(NHPP-SRGMs) are quite successful tools which have been proposed to assess the reliability of software, however, most NHPP-SRGMs do not take the phenomena of defect correlation in the test process into account. Considering the correlation of software defects, this paper promotes an improved NHPP-SRGMs. Experimental results show that the proposed model fits the failure data quite well and has a fairly accurate prediction capability.
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Computer Engineering. 2008, 34(8): 47-49. https://doi.org/10.3969/j.issn.1000-3428.2008.08.016This paper investigates the NPA algorithm suggested by Keerthi et al commonly used in support vector training, points out its defects, and presents a modification. It takes Gilbert iteration in the early stage of type-Ⅰloop and NPA iteration in the later stage, and proposes a strategy of how to determine these two stages. It optimizes the NPA iteration in type-Ⅱloop by employing previously obtained computation results. In comparison with NPA, the modified version results in a remarkably accelerate convergence without increasing in computational complexity. By virtue of it, an experimental automated classifier is developed, which shows satisfactory performance.
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Computer Engineering. 2008, 34(8): 50-52. https://doi.org/10.3969/j.issn.1000-3428.2008.08.017Exception propagation will bring a lot of difficulties in analyzing, understanding, testing and maintaining programs. To solve the problem that the representation is too complex in describing exception propagation path, based on C++ exception handling, this paper proposes an exception control flow graph model. It constructs an exception propagation graph model based on analyzing various relationships in the course of exception propagation, and discusses the application of the exception propagation graph in the structure testing. Using this graph can show a clear and precise exception propagation path and greatly simplify the analysis.
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Computer Engineering. 2008, 34(8): 53-55. https://doi.org/10.3969/j.issn.1000-3428.2008.08.018When dealing with massive volume data, there’ are two ways to achieve high performance: —one is to compress and the other one is to build index. Combining these two waysmethods, compressed query is emergingproposed. FM-index is such a compressed self-index algorithm used for full-text query. We found that The algorithm will occupiesy a large amount of main memory and is unable to handle complex query efficiently. To deal with these problems, this paper we proposesd a blocked version FM-index algorithm and parallelizesd it using MPI. The blocked algorithm greatly reducesd its memory usage, while the parallel version of blocked FM-index algorithm achievesd acceptable scalability.
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Computer Engineering. 2008, 34(8): 55-58. https://doi.org/10.3969/j.issn.1000-3428.2008.08.019This paper analyzes the features and demerits of traditional data modeling, imports a unified data model for knowledge to support uniform knowledge management and information integrating in the e-government domain. Based on the unified data model, it designs and implements a unified development environment for building knowledge management platform. The practice proves that building knowledge management platform based on the unified data model for knowledge makes the system manage all kinds of knowledge in a consistent way and adapt to application of new kinds of knowledge quickly.
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Computer Engineering. 2008, 34(8): 59-61. https://doi.org/10.3969/j.issn.1000-3428.2008.08.020In distributed networks, current peer-to-peer trust model can not solve the problem that the peer has different trust evaluation results because of different interface experiences in different situations. This paper proposes a trust evaluation model based on individual experience through introducing experience factor and comparative experiential factor and analyzes its efficiency. The simulation results show that the model has more improvements on the algorithm of feedback trust value.
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Computer Engineering. 2008, 34(8): 62-65. https://doi.org/10.3969/j.issn.1000-3428.2008.08.021Dedicated to the deficiencies in real-time characteristic, concurrency and other performance of short message applications controlled by the Modem, a real-time concurrent algorithm for short message control based on multi-queue structure and multithread technology is introduced, with a practical project as the background. The algorithm is built on the basis of queuing theory model and adopts multi-queue, multithreading, pool and some other technical means to ensure the real-time characteristic, concurrency and data sharing of short message control. This paper also validates the algorithm via queuing theory model and experiments, so that the results indicate that the algorithm increases the speed and the efficiency of the short message sending and receiving to a great extent, consequently satisfies the requirement for real-time characteristic and concurrency, and improves the overall performance of the short message applications.
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Computer Engineering. 2008, 34(8): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2008.08.022To integrate existing database resources into the grid and encourage wider use of databases in a grid setting, a service-based database access and integration system, GridDBAdmin, is presented. GridDBAdmin provides a virtual global logical database view for the users and enables grid application to query existing multiple databases using SQL. The system is composed with MetaData Service(MDS) and Grid Virtual Database Service(GVDS). MDS searches the metadata catalog to find the physical databases that contain the required data. GVDS delegates global logical database and converts SQL query into search conditions to the physical databases, which uses a distributed query processing scheme to join multiple physical databases. Performance evaluation based on the response time shows the efficiency of the method. The system is fully implemented on the top of the Globus toolkit and OGSA-DAI.
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Computer Engineering. 2008, 34(8): 69-71. https://doi.org/10.3969/j.issn.1000-3428.2008.08.023To implement the fast recovery of application system by cutting unnecessary recursive overhead during the recursive restartability, a decision approach to microreboot group is proposed based on microreboot technology. By the aid of load testing and exception injection during the test, the approach obtains the average failure frequency of components. After that, failure correlation degree between components is analyzed and the decision algorithm of microreboot group is specified. Research results show that the approach can reboot the system against different failure in componentized distributed applications. As a result, mean time to recovery decreases by about thirty percent.
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Computer Engineering. 2008, 34(8): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2008.08.024Most differences between spatial association rules and traditional association rules are the fact that distance relation, direction relation and topology relation of the spatial entity are needed to be taken into account. The spatial concept layer relations are based on cell pattern or theme. In the paper, the spatial association rules algorithm is discussed, a multi-level spatial association rules algorithm based on concept tree is proposed, a spatial data mining prototype system based on J2EE is designed and implemented, and an example based on the land use of one city is used to further explain the implementing process. The spatial association rules of the eight types of land use, which are acquired by the system, prove the realistic value.
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Computer Engineering. 2008, 34(8): 75-76. https://doi.org/10.3969/j.issn.1000-3428.2008.08.025Around the characteristics of general purposes, loosely-coupled, dynamic performance, this paper studies basic strategy of SOA, puts forward flexible SOA, universally privilege management, localization of services, and implements universally privilege management based on flexible SOA. The strategy is applied to the PLM system based on Web. Experimental results show the strategy is effective.
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Computer Engineering. 2008, 34(8): 77-79. https://doi.org/10.3969/j.issn.1000-3428.2008.08.026This paper presents a logical means for expressing access control, which satisfies the condition of least model semantic that has no negative, and analyzes an iterative algorithm for calculating the fixpoint of the logic program corresponding to the access control. According to the iterative algorithm, it calculates the least Herbrand model of logic program corresponding to the access control. Access control strategy is reasoned, through logical program, which makes reasoning of access control effectively.
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Computer Engineering. 2008, 34(8): 80-81. https://doi.org/10.3969/j.issn.1000-3428.2008.08.027Memory allocation is an important issue in developing real-time and embedded applications. This paper introduces a novel memory allocation algorithm which uses hybrid of bitmap fit and segregated fit. It uses a double bitmap fit when the memory block is small, which uses a double segregate list to manage larger memory blocks in order to lower fragmentation. Experimental results show the method has low fragmentation and a bounded response time, which is suit for real-time systems.
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Computer Engineering. 2008, 34(8): 82-84. https://doi.org/10.3969/j.issn.1000-3428.2008.08.028The data dimension reduction is a method that can enhance the outliers mining efficiency based on higher-dimension data set. This paper analyzes classical outlier mining algorithm, proposes a novel outlier detection algorithm, transforms nonlinear large-scale data into linear data in the feature space, and introduces a kernel function and principal component data transformation to reduce data dimension. On the basis of each resulting vector, it is determined which data is outlier data one by one. This paper shows that the algorithm is used to detect linear separable outlier data, and to detect nonlinear inseparable outlier data. Experimental results indicate that the algorithm is predominant.
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Computer Engineering. 2008, 34(8): 85-86. https://doi.org/10.3969/j.issn.1000-3428.2008.08.029An effective and precise pattern matching algorithm is important to intrusion detection system. This paper introduces the principles of pattern matching algorithms, analyzes Wu_Manber multi-pattern matching algorithm and improved methods, and provides a QMWM method. The method uses prefix information, optimizes the shift distance, and does not need additional space complexity. Experimental results show that, on the basis of improving the efficiency, the algorithm does not need extra space and can increase the space utility ratio.
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Computer Engineering. 2008, 34(8): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2008.08.030Requirement analysis is an important link in the course of software development. This paper discusses the problem existing in the requirement analysis process, and puts forward a requirements specification meta-model. It has some directed effect to capture the acquisition of customer’s functional demand and to normalize and improve the analysis methods. Domain oriented software requirements specification generation tool is designed based on the meta-model. A field-based logistics management system orders illustrate the application of the requirements specification tool.
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Computer Engineering. 2008, 34(8): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2008.08.031It is a key problem to guarantee the consistency of POS(Part of Speech) tagging of Chinese corpus. After analyzing the POS tagging in the large-scale corpus, the new consistency check method of POS tagging are put forward. This paper builds the vector model of the context of trans-classed word, then uses k-NN to classify the POS tagging sequence vectors, judges their consistency, and obtains circumstances of the consistency of POS tagging of every text. The methods are evaluated on our 1 5000-word corpus.
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Computer Engineering. 2008, 34(8): 93-95. https://doi.org/10.3969/j.issn.1000-3428.2008.08.032According to the SOA, this paper proposes the framework of composite service execution engine WebJetFlow. In this framework, to guarantee the response time from different services of different levels, it designs and implements the flow execution structure with dual feedback control loops, which are in the process executor and service proxy respectively. Moreover, it separates process executor and service proxy to decouple process execution and service invocation. The new idea is that decoupling method improves the efficiency and throughput of the engine, and introduces the feedback control mechanism that enables the engine to provide response time guarantees for different services even when load varies significantly.
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Computer Engineering. 2008, 34(8): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2008.08.033Through introducing an appropriate redundancy in directed diffusion, this paper proposes a new extended routing protocol. The basic principles of the protocol are introduced. The performance of the scheme and the detection of some flavours of attacks are given. Simulation results show that the redundancy can get a high arrival rate and the detection can be carried out smoothly. The new protocol reduces the number of data packet transmission.
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Computer Engineering. 2008, 34(8): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2008.08.034This paper proposes a new model for evaluating IP networks’ synthetical performance. Combined with the concept of network health and router health, the model gives a collective evaluation on the network, which provides a different view of the network performance. Based on the model, a tool “NHES” is built to test the China Mobile CNGI Experimenting Network. Experimental results show that the model can evaluate the network performance effectively.
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Computer Engineering. 2008, 34(8): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2008.08.035For nowadays multicast technologies, IP multicast is hampered by a host of unresolved problems such as deployment and scalability, overlay multicast is needed to be improved with concerns relating to performance and robustness, a large number of communication systems support hardware multicast, which has never been utilized effectively. This paper presents a novel architecture named Nodes Self-organized Multilayer Multicast(NSMM) to integrate the advantages of related technologies in different layers, introduces the primary design of NSMM, and compares it with existing multicast methods.
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Computer Engineering. 2008, 34(8): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2008.08.036HRED is designed to make high speed flows, regular TCP flows and UDP flows fairly share bandwidth in high-speed network. Using the packet drop history of RED, HRED identifies high-speed flows, and punishes high bandwidth flows to let the low bandwidth flows get more bandwidth. Per-flow state information is not needed, so HRED is scalable. Extensive simulations with NS2 show that HRED can realize better RTT fairness in high-speed networks, and can let responsive flows and non-responsive flows share bandwidth fairly.
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Computer Engineering. 2008, 34(8): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2008.08.037In order to lead the Peer to Peer(P2P) traffic and reduce bandwidth occupancy at key location, this paper brings forward a peer selection algorithm based on file piece merging degree using BitTorrent(BT) as an example which is a P2P software used by large-scale people. Applying the algorithm, BT traffic can be leaded and optimized. P2P traffic between networks is reduced heavily, which is testified by modeling and analyzing the peer selection algorithm based on piece inosculation degree.
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Computer Engineering. 2008, 34(8): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2008.08.038Data-reuse can accelerate the convergence rate of the blind equalization algorithm, while it also brings about the problem of noise magnifying. A novel blind equalization algorithm with fast convergence rate is presented by applying data-reuse to the modified constant modulus algorithm that processes the real and imaginary parts of received signal separately, and the set-membership filtering is adopted to solve the problem of noise magnifying caused by data-reusing. Simulations show that the new blind equalization algorithm is of fast convergence, thus is suitable for short burst signal processing.
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Computer Engineering. 2008, 34(8): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2008.08.039The replay of the application’s behavior is essential to the protocol design, network troubleshooting, performance evaluation and network management. It is important to develop a simple and powerful method to implement the replay of the application’s behavior which is complicated along with the appearance of new applications. Based on the detailed analysis of the most of all the typical replay-methods and frameworks related to the application’s behavior, it gives a new replay-method based on template which is rely on the systemic classification of all the application’s behaviors. As the presentation of the experimental results, using the method, it reduces the complexity of building a repay-system of application behavior, especially when adding new applications into the replay-system.
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Computer Engineering. 2008, 34(8): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2008.08.040A general infrastructure of grid computing is not suitable for more and more dynamic and heterogeneous resource. This paper presents Agent based architecture for adaptive grid computing. Using autonomy and adaptability, it can increase the capacity of system self-healing. The model based on this architecture with timed-coloured Petri nets is formalized. The paper also simulates and analyzes it by timed-coloured Petri nets. The results of simulation illuminate the validity and feasibility of the model.
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Computer Engineering. 2008, 34(8): 120-122. https://doi.org/10.3969/j.issn.1000-3428.2008.08.041According to the autonomy, heterogeneity, and distributed nature of grid computing system, the paper proposes a new grid scheduling algorithm to reduce average task response time with dynamic prediction and task flow shaping. The algorithm uses history data and the recent task request time, task completion time, and network communication delay, to predict the future task response time at each computing node. Based on the prediction result, tasks will be assigned to compute nodes which are predicted to have less work load and better performance in the near future. The resource utilization can be improved by both the dynamic adaptation algorithm and the task flow shaping algorithm. Experimental results show that approach outperforms existing scheduling algorithms(e.g., random scheduling) in terms of task response time and throughput.
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Computer Engineering. 2008, 34(8): 123-125. https://doi.org/10.3969/j.issn.1000-3428.2008.08.042An effective routing algorithm is presented for the multi-stage rearrangeable optical switching network. The input and output terminal numbers are mapped into the center stages, then two interchangeable groups which can exchange corresponding terminal numbers are obtained. Furthermore, the algorithm rearranges the sequence of input and output terminal numbers in the interchangeable groups, consequently, ascertains the status of center node switch. The next step is to route the network in a bi-directional way and determine similarly the status of the remaining stages in both sides. This algorithm runs very fast and effective because of routing the network in a bi-directional way, so only requires O(N) routing steps. It is proved that this algorithm can be implemented in optical interconnection networks for optical switching and permutation.
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Computer Engineering. 2008, 34(8): 126-127. https://doi.org/10.3969/j.issn.1000-3428.2008.08.043High performance routers presently take the measure of hardware methods based on TCAM to realize high speed routing lookups. But the longest prefix matching complicates the updates of TCAM. This paper proposes a two stage forwarding tables managing method, to improve the poor performance of present method when updates come burstily, and researches the performance of the method through simulation. Simulation results prove that the method keep the forwarding system stable in burstiness.
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Computer Engineering. 2008, 34(8): 128-129. https://doi.org/10.3969/j.issn.1000-3428.2008.08.044H.248 has been adopted as the primary protocol to control the media gateway in Next Generation Network (NGN) soft switch system. The paper introduces the H.248 protocol briefly and advances the unreliability in transportation based on IP. Then it analyzes the mechanism of reliable transportation, and gives a solution to reliable transportation based on IP. Outcomes of the initial realization prove the feasibility of this design. It ensures the reliability of transportation and increases the efficiency of signaling process.
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Computer Engineering. 2008, 34(8): 130-131. https://doi.org/10.3969/j.issn.1000-3428.2008.08.045By utilizing the property of circle that t points given on the same t-1 dimensional circle can determine its formula uniquely, a geometry-based threshold scheme is designed in this paper. It is simple but has high security. It can change sharing secret and keep at most t-1 users shadow unchanged.
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Computer Engineering. 2008, 34(8): 132-134. https://doi.org/10.3969/j.issn.1000-3428.2008.08.046Symmetric encryption scheme is proposed based on two symmetric-keys. By mean of a very sensitive function with a private key and a changeable “public key”, the proposed scheme has a function similar to one-time pad scheme. Using a Lorenz system with mode function illustrates how to realize such encryption scheme. Theoretical analysis and experimental results demonstrate that the new scheme can increase the security of traditional encryption scheme and be easy to be realized.
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Computer Engineering. 2008, 34(8): 135-135. https://doi.org/10.3969/j.issn.1000-3428.2008.08.047Based on the analysis of 41 popular block ciphers, the paper researches the features of 4 of kinds of popular substitution boxes, which are 4×4, 6×4, 8×8 and 8×32, and analyzes the realization mode of the substitution boxes. It describes special instructions, which can perform 4 kinds of popular substitution boxes quickly and flexibly, extends the usage of special instruction to the VLIW structure instruction, and designs the hardware module of the substitution box. Performance of special instructions are analyzed by comparing it with other instructions.
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Computer Engineering. 2008, 34(8): 138-140. https://doi.org/10.3969/j.issn.1000-3428.2008.08.048Traditional algorithms using sequences of system calls often pay close attention to the length of the sequences while ignoring the importance of their occurring frequency. A new detection algorithm using sequences of system calls is put forward based on their occurring frequency, the classifier may pay more attention to the importance of different sequences which is defined by their occurring frequency. Experiments using IS data sets show that the new model has a low false positive rate compared with the traditional model. And hence, adjusting some parameters can make the false positive rate better.
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Computer Engineering. 2008, 34(8): 141-143. https://doi.org/10.3969/j.issn.1000-3428.2008.08.049This paper presents a steganalysis scheme which can effectively attack JPEG steganographic. The method exploits the first and the second order statistic characteristics. It extracts these characteristics of histogram and the partial statistical characteristics of intra-block and inter-block from the cover-images and the stego-images respectively. In order to achieve the purpose of general detection, it uses Support Vector Machine(SVM) to train and distinguish these characteristics, and establishs the model. Experimental results show that the method performs well in steganalysis methods such as Jsteg, F5, OutGuess, and MB.
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Computer Engineering. 2008, 34(8): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2008.08.050Dictionary-steganograhpy is a method using texts to hiding secret information, which transforms secret message directly into stego-text similar to ordinary text using a dictionary. This paper analyzes the statistical characteristics and finds the differences of the stego-text and natural lingual text by modeling the latter, which shows frangibility of the traditional algorithm. The paper improves the dictionary of the algorithm, which makes the stego-texts similarly to natural texts on familiar statistical characteristics. This improvement makes up the shortages and improves the security of the traditional algorithm.
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Computer Engineering. 2008, 34(8): 147-149. https://doi.org/10.3969/j.issn.1000-3428.2008.08.051The paper elaborates on IKE protocol with pre-shared Key authentication in main mode and puts forward corresponding advises to the potential secure flaws and the disadvantage of not supporting road warrior users. The proposed scheme can detect the attack quickly by authenticating the messages at once and prevent the identity of senders and receivers from being got by others, with no limitation to fixed IP address. It is secure, efficient and feasible.
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Computer Engineering. 2008, 34(8): 150-152. https://doi.org/10.3969/j.issn.1000-3428.2008.08.052Aiming at the detection of hidden information in steganalysis, a steganalysis approach is advanced based on many methods by using Bayes classification with independent two value. Analysis of classification effect and parameters’ control are given. The result shows that the approach can reduce False Detection Rate (FDR) and False Alarm Rate (FAR) and control classification effect by adjusting parameters. Applying the approach to LSB steganagraphy, experimental results show that it improves the classification effect. Its FDR is the second best and FAR cuts more than half.
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Computer Engineering. 2008, 34(8): 153-155. https://doi.org/10.3969/j.issn.1000-3428.2008.08.053Malicious codes have become a main threat to computer security. They take various obfuscation techniques to hide themselves in order not to be statically analyzed. Conditional jump obfuscation is one of such techniques. This paper analyzes the reason lead to the conditional jump obfuscation and modifies the disassembly algorithm in the reverse analysis tool named Radux. Relevant test shows that the method is effective to get the correct disassembly result from the malicious codes obfuscated with conditional jumps.
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Computer Engineering. 2008, 34(8): 156-158. https://doi.org/10.3969/j.issn.1000-3428.2008.08.054Security is difficult to handle in multi-privileged group communications, because group users have multiple access privileges when subscribing different data streams. This paper proposes an efficient group key management protocol in multi-privileged group communications. The protocol assigns a unique ID to each node on key graph. With the special relationship among the nodes’ IDs, group users can deduce the new keys with one-way function according to the ID of joining/leaving/changing node on the key graph, thus the protocol can greatly reduce the rekeying overhead. Simulation results show that compared with the MGKMS protocol, the protocol can reduce the rekeying overhead by 70% in the best case.
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Computer Engineering. 2008, 34(8): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2008.08.055In order to reduce the complexity of computation and improve the generalization of two binary-class support vector machines in images steganalysis, this paper brings forward a steganalysis method based on genetic algorithms and multiple one-class SVM. Genetic algorithm is applied to search and identify the potential informative features combinations for classification. The classification accuracy from the support vector machine classifier is used to determine the fitness in genetic algorithm. Experimental results show that the efficiency of detecting system is improved.
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Computer Engineering. 2008, 34(8): 162-163. https://doi.org/10.3969/j.issn.1000-3428.2008.08.056A general secret sharing scheme based on the LUC cryptosystem is proposed. In this scheme, each participant’s private key is used as his secret share, and the secret dealer needn’t distribute each participant’s secret share. In recovery phase, each participant is allowed to check whether another participant provides the true information or not. Each participant can share many secrets with other participants by holding only one shadow.
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Computer Engineering. 2008, 34(8): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2008.08.057This paper analyzes the security of the authenticated key exchange protocol WAI in WAPI, points out its flaws and improves it. The security proof of the new protocol WAI’ in CK security model is given, which indicates that WAI’ has the corresponding security attributes in CK security model, and satisfies the requirements of WAPI.
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Computer Engineering. 2008, 34(8): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2008.08.058A hiding information algorithm of adaptive multiple plane-bit based on space domain is proposed ,which has low computing complexity and large information capacity hidden. Experimental results show hiding information capacity of this algorithm is much larger than LSB algorithm, and security is much higher than LSB algorithm. It’s main idea is to judge every pixel point so that hiding information will be embedded from specified bit (y) behind the highest non-zero effective bit until another specified bit (z) according to HVS’s property.
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Computer Engineering. 2008, 34(8): 170-171. https://doi.org/10.3969/j.issn.1000-3428.2008.08.059Based on the LSB detection algorithm of lossless data embedding that is brought forward by Jessica Fridrich, the paper discusses some main effecting factors through experiment, and analyzes the root cause of these factors. An improved RS detection algorithm is proposed, which can minimize the deviation of detection.
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Computer Engineering. 2008, 34(8): 172-173. https://doi.org/10.3969/j.issn.1000-3428.2008.08.060Authenticated key agreement is an important original language of cryptology. This paper analyzes an ID-based authenticated key agreement protocol, carries a proof of security in the Bellare-Rogaway-93 model, pointes out the protocol is insecure if the adversary is allowed to send a Reveal query. Researches show that the protocol can not resist the key compromise impersonation attack.
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Computer Engineering. 2008, 34(8): 174-176. https://doi.org/10.3969/j.issn.1000-3428.2008.08.061This paper analyzes security threats of firmware BIOS, and defines the concept of trusted BIOS. The architecture of UTBIOS, which is based on UEFI specification and trusted computing mechanism, is developed. To construct Pre-OS chain of trust, CRTM embedded in UTBIOS is used to measure the trustworthiness of entities in different phases of bootstrap. Implementation of UTBIOS based on UEFI BIOS product is described and the performance of trusted measurement is analyzed.
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Computer Engineering. 2008, 34(8): 177-178. https://doi.org/10.3969/j.issn.1000-3428.2008.08.062A type flaw attack on a security protocol is an attack where a field that is originally intended to have one type is subsequently interpreted as having another type. This paper describes type flaw attacks through some typical attack examples, and analyses the limitations of tagging scheme of preventing type flaw attack by J.Heather et al. In addition, other methods against type flaw attack by checking message length are presented.
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Computer Engineering. 2008, 34(8): 179-181. https://doi.org/10.3969/j.issn.1000-3428.2008.08.063Aiming at current existed problems of single sign-on applied to Web services security, this paper puts forward a single sign-on model for Web services authentication and authorization with the help of WS-Security and SAML, and analyzes the flow and security of this single sign-on system. The system has compatibility and better expansibility it can be deployed easily.
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Computer Engineering. 2008, 34(8): 182-183. https://doi.org/10.3969/j.issn.1000-3428.2008.08.064This paper presents a model of anonymous communication system based on rerouting. Based on the system model, a attack algorithm is proposed, which adopts a transmission strategy with the fixed length and changeable rerouting path. Attackers can observe the system multitudinously with many companions. Computation and analysis indicate that probability of the attacker’s finding out the sender is inversely proportional to path length, proportional to observation frequencies and the number of companion. It is proved that the attack model can effectively destroy the anonymity degree of the senders.
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Computer Engineering. 2008, 34(8): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2008.08.065This paper analyses the disadvantages of the existing intrusion detection technology and discusses the advantages of intrusion detection based on outlier mining, a new intrusion detection method based on kernel density estimator called IDKD is proposed. In IDKD, the approximate set of outliers is calculated by kernel density estimator through one data set pass, and the indeed set of outliers is generated from the approximate set by another data set pass, the anomaly records are detected. This method is applied in KDD99 data set and gets satisfactory results.
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Computer Engineering. 2008, 34(8): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2008.08.066This Paper introduces the security threats of Neighbor Discovery Protocol(NDP), and analyses the mechanism of Secure Neighbor Discovery (SEND), which is the current security algorithm, to prevent nodes from spoofing attacks by adding some options to the NDP packets, eg. CGA and RSA signature option, etc. In order to solve the management problem of public key in SEND, Public Key Infrastructure(PKI) is introduced to establish secure communication using certifications, which can improve the security of NDP.
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Computer Engineering. 2008, 34(8): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2008.08.067The group data encryption algorithm is proposed for digital speech codes. The method uses the UDP protocol to cipher message. It partially solves the problem that some data packages lost during transportation. This method encrypts message with chaotic sequences which randomly come from chaos database, so randomicity of whole chaotic sequence is enhanced greatly. Further more, it can overcome the disadvantage of short period when data are a great deal. The algorithm is testified with test program written by author.
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Computer Engineering. 2008, 34(8): 193-194. https://doi.org/10.3969/j.issn.1000-3428.2008.08.068With the development of information system, most practical applications have dynamic attributes, but conventional access control mechanisms have not addressed the problem efficiently. This paper discusses how to realize an access control system that enables to manage dynamic security policies. The proposed method is based on Role-based Access Control (RBAC), and the agent decides access rights dynamically for the abstract role, according to the definitions of the abstract roles, context information and rules, agent acquire actual role by inference module, demonstrate the structure of the model and usefulness of the proposed system by presenting the project management application and its access control system. Experimental results verify that the model is more efficient and securer than traditional access control model.
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Computer Engineering. 2008, 34(8): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2008.08.069The diversity and severity of fishing attacks bring great threats to confidential data management such as identity management. This paper proposes a method which combines trusted computing technology and SSL(Secure Socket Layer) to prevent fishing attacks based on comparing current mechanisms for preventing fishing after introducing some main kinds of current fishing attacks and analyzing the rationale of it. The security analysis shows that the proposed method can prevent current main kinds of fishing attacks effectively.
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Computer Engineering. 2008, 34(8): 198-199. https://doi.org/10.3969/j.issn.1000-3428.2008.08.070In order to prevent the permanent information of a user from being identified by a rogue, the 3G security architecture is researched. By analyzing the mechanism of access security of UMTS systems, especially authentication and key agreement, this paper finds a method for authentication. The main idea of the method is to verify the random parameter RAND for authentication by USIM. If the process is not successful, USIM will respond fault result parameter; otherwise will respond correct result parameter. This method can ensure the identification information not been listened easily and improve the level of confidentiality the furthest. The period of putting in practice for the method is short.
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Computer Engineering. 2008, 34(8): 200-202. https://doi.org/10.3969/j.issn.1000-3428.2008.08.071In this paper, a new algorithm called the multi-objective ant-genetic algorithm, which is based on the continuous space optimization, is presented to solve constrained multi-objective optimization problems. For the trait of multi-objective optimization, the strategy of inheritance searching under the instruction of pheromone and the method of updating pheromone are defined. Then three means are combined together so that the constringent speed of searching has been improved a lot and the quantity of Pareto optimal decisions are controlled, also the distributing area of decisions is enlarged, the diversity of the swarm is maintained. The termination conditions of multi-objective ant-genetic algorithm are presented. An example is listed to prove that the algorithms are effective, and it can find a group of widely distributed Pareto optimal decisions.
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Computer Engineering. 2008, 34(8): 203-204. https://doi.org/10.3969/j.issn.1000-3428.2008.08.072This paper analyzes the connection between equivalence relation and granulation based on rough theory. A method of rough clustering based on granulation is presented. The method evaluates relative similarity relation to each object to form initial equivalence relation, and the equivalence class is developed. Each equivalence class may be viewed as a granule consisting of indistinguishable and similarity elements. Using a newly introduced measure, equivalence relation membership, the method evaluates subordination degree of equivalence relation to modify the scale of clustering during clustering process. The optimal clustering result can be obtained by evaluating the cluster validity with various values of similarity thresholds. From the view of granularity, the clustering is a computation under the same granularity. Experimental results show that the method is effective, the clustering results described by rules set are interpretable and rational.
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Computer Engineering. 2008, 34(8): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2008.08.073The dimensionality reduction techniques are very important for high-dimensional nonlinear data to complete the processing and analysis of the high complexity data source. From the view of topology, the process of dimensionality reduction is to find a low-dimensional linear or nonlinear manifold embedded in the high-dimensional data. On the basis of locally embedding manifold learning algorithms, a data dimensionality reduction algorithm based on direct estimate grads is proposed. The dimensionality reduction of the high-dimensionality nonlinear data is achieved by locally linear error approximating minimum. The simulation results of Swiss roll curse sampling and test show the significant effectiveness of the proposed algorithm.
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Computer Engineering. 2008, 34(8): 208-209. https://doi.org/10.3969/j.issn.1000-3428.2008.08.074To increase the speed of finding the optima in evolutionary algorithms, two mutation operators are designed, and a new evolutionary algorithm based on them is proposed. The algorithm emphasizes the population diversity, the convergence speed, the balance of global search ability and local search ability. Its global convergence is proved by the theories of probability and Markov chain. The test results of six benchmark functions indicate the algorithm improves the performance effectively.
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Computer Engineering. 2008, 34(8): 210-212. https://doi.org/10.3969/j.issn.1000-3428.2008.08.075The fuzzy clustering is introduced into information issuing problem of variable message signs. Three traffic flow parameters (flow, speed, occupancy) are analyzed using fuzzy clustering. Traffic flow situation on expressway is classified and recognized, and it provides the basis for issuing the effective VMS information. Traffic flow situation is classified into three categories, namely the clustering number is 3. Clustering centers are obtained and traffic flow situation is recognized. Traffic information is issued to the drivers through VMS.
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Computer Engineering. 2008, 34(8): 213-215. https://doi.org/10.3969/j.issn.1000-3428.2008.08.076This paper proposes a novel method for mobile robot path planning. The data gotten from eight sonar transmitters mounted in the robot front is fused with that gotten from a CCD camera mounted on the robot back deck to obtain the location of obstacles. The algorithm needs much less calculation than that just uses vision, and more accurate than that uses sonar only. According to the fused obstacles information, a local best path for the robot is planed using the tangent method. Experimental results show that the method has an effective performance.
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Computer Engineering. 2008, 34(8): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2008.08.077A color image authentication algorithm is presented. Message of each pixel is convolution encoded by encoder. After the process of parity checking and block interleaving, redundant bits are offset embedded in the image. Tamper can be detected and restored in pixel-level without accessing original image. Experimental results show the authentication algorithm has good performance in tamper detection, localization and image reconstruction.
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Computer Engineering. 2008, 34(8): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2008.08.078This paper introduces fuzzy entropy into the procedure of exploring parameters of Fuzzy Production Rules(FPRs). A parameter optimization model based on maximum fuzzy entropy principle is proposed and a Pareto strength evolutionary algorithm is introduced to solve this model. Experimental results show that the trained parameters gained from above strategy are highly accurate, therefore this method can decrease the phenomenon of over-fitting and improve the knowledge representation capability of FPRs.
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Computer Engineering. 2008, 34(8): 221-222. https://doi.org/10.3969/j.issn.1000-3428.2008.08.079Multi-objective genetic algorithms are effective in solving SoC system level synthesis. These available algorithms can only attain part of the whole Pareto front, because of the worse local searching ability, the convergence speed is slow. In order to overcome these disadvantages, an updated multi-objective genetic algorithm, self-adaptive niching genetic algorithm, is proposed, which integrates the niching technique, self-adaptively adjusts the sub-populations’ size and the probabilities of crossover and mutation by using the previous population’s diversity information. It can effectively increase the solutions coverage and improve the convergence speed. Using the updated algorithm, this paper succeeds in optimizing the synthesis of video codec. Result indicates that the new algorithm can rapidly acquire more Pareto optimal solutions and proves the superiority of the algorithm.
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Computer Engineering. 2008, 34(8): 223-225. https://doi.org/10.3969/j.issn.1000-3428.2008.08.080Based on the total variation methods of gray-scale image inpainting, this paper presents four steps to achieve a color image inpainting: It labels the images to be inpainted, obtains the mask image by labeled pixels, expands the mask image, inpaints the images with the expanding information. Experimental results on related images show that the inpainting result is very well, color image with noise can get good denoised result and keep clear border.
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Computer Engineering. 2008, 34(8): 226-228. https://doi.org/10.3969/j.issn.1000-3428.2008.08.081This paper deals with the problem of finding the largest passable areas around a mobile robot. It proposes a method to obtain reliable dense 3D depth maps using a novel omnidirectional stereo vision system. The vision system is composed of a perspective camera and two hyperbolic mirrors. Once the system has been calibrated and two image points respectively projected by upper and below mirrors are matched, the 3D coordinate of the space point can be acquired by means of triangulation. To achieve the largest reliable dense matching, the method is divided into three steps: reliable FX-dominant matching, feature matching and ambiguous removal. The remaining points between features are matched using dynamic programming with modified energy functions adapted well to the system. Experiments show that the vision system is feasible as a practical stereo sensor for accurate 3D map generation.
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Computer Engineering. 2008, 34(8): 229-231. https://doi.org/10.3969/j.issn.1000-3428.2008.08.082This paper proposes a General Ontology Learning Framework(GOLF), dicusses the key technologies of ontology learning such as domain concepts extraction, semantic relationships between concepts and taxonomy automatic construction and ontology evaluation methods. By integrating many machine learning algorithms, this approach suffers less ambiguity and can identify domain concepts and relations more accurately. By using generalized corpus WordNet and HowNet, the method is applicable across different domains. By obtaining source documents from the Web on demand, the method can produce up-to-date ontologies.
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Computer Engineering. 2008, 34(8): 232-234. https://doi.org/10.3969/j.issn.1000-3428.2008.08.083This paper presents a novel method to model two-dimensional feather with a collection of Hermite curves, which makes rending of feathers be more convenient based on vector characteristic of Hermite curves. By the variation of some parameters, all sorts of feathers can be generated automatically. In order to improve the reality of feather, it supplies the barbs with texture. On the basis of two-dimensional feather, a three-dimensional feather model is constructed according to its structural characteristics. The method is as easy and clear as two-dimensional feather.
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Computer Engineering. 2008, 34(8): 235-237. https://doi.org/10.3969/j.issn.1000-3428.2008.08.084Focusing on the typical fast motion estimation algorithms without consideration on other characteristics of H.264/AVC, this paper introduces an improved fast motion estimation algorithm. In this algorithm, integer transform and motion vector predictor, search range, reference frame and the relativity of coding block modes are thought together. Experimental results show that it can save more encoding time while maintaining coding efficiency.
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Computer Engineering. 2008, 34(8): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2008.08.085Terrain walkthrough is a hot point in GIS, virtual reality and military simulation fields. large Large scale terrain algorithm is used to load data partly into the memory, then simplify terrain to speed up drawing-rate. This paper presents an algorithm which blocks the terrain, and uses back culling and modifieds deviation equation to construct lLevel oOf dDetail(LOD), and then uses a new horizon culled method based on screen-deviation bounding box. This algorithm has a fast drawing-rate. Besides, memory mapping file technique to load DEM data is used to make the algorithm have high performance data process ability.
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Computer Engineering. 2008, 34(8): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2008.08.086This paper analyzes the problems of push, pull and hybrid mode based Peer-to-Peer(P2P) live system. A phased push and pull combined P2P live media streaming system is designed. A peer evaluation mechanism and Gossip protocol are introduced to adjust the double topology of overlay network. A patching mechanism is used to reduce the start delay. The test results show that it can efficiently reduce the burden of the network transmission and improve the speed of data distribution.
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Computer Engineering. 2008, 34(8): 243-245. https://doi.org/10.3969/j.issn.1000-3428.2008.08.087In view of the Next Generation Network(NGN)’s characteristic, this article proposes a Session Initiation Protocol(SIP)-based lawful interception solution which may be used in the next generation network. After thorough analysis of the Cisco’s IP-based Lawful Interception architecture and combined with SIP call setup flow, it is introduced into the NGN. The result proves this implementation of lawful interception in NGN is feasible and safe.
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Computer Engineering. 2008, 34(8): 246-248. https://doi.org/10.3969/j.issn.1000-3428.2008.08.088By analyzing the end-to-end distortion, the influence of motion vector selection on error propagation is studied. Allowing for that traditional motion estimation algorithm only takes into account the prediction error within source encoding framework, which is no longer accurate in lossy environment, an end-to-end prediction error calculation method is proposed. This prediction error is used in the rate-distortion optimized selection of motion vectors. Simulations have been done based on H.264 standard. The results show that for low-bit-rate video transmission over Internet, the robustness of video stream and the decoded video quality are improved by appling the proposed algorithm.
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Computer Engineering. 2008, 34(8): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2008.08.089Statistical results demonstrate that the application of multiple reference frame motion compensation in coding process can only improve the coding efficiency of video sequence which has scene changes. However, the coding gain for most video sequence is not so significant. Therefore, an optimal multiple frames predictive scheme is given through analyzing motion information of current sequence. The algorithm utilizes the motion feature of the sequence as threshold to judge the maximum reference frame, the result of current reference frame and neighbor macroblock mode to decide whether to search another reference frame or not. Experimental results show that the proposed approach can get 2.10 times~2.65 times coding speed compared with full search greatly with similar visual quality.
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Computer Engineering. 2008, 34(8): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2008.08.090To meet the azimuth preprocessing requirements of the high resolution multimode SAR, this paper presents a preprocessor based on the high-speed ADSP-TS201 chip from AD company. The order of FIR filter, the precision of calculation and the length of range lines are greatly improved. The parameters of the preprocessor are changeable in real time according to different demands. In this paper, the principle of the preprocessor is introduced, and the DSP code is optimized according to the architect and instruction characteristic of TS201. When the order of the FIR filter is 64, desampling ratio is 4 and the length of the range line is 16 384, the input PRF of the preprocessor can exceed 1 800 Hz.
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Computer Engineering. 2008, 34(8): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2008.08.091Aiming at USB storage device, this paper presents a design scheme of security monitoring based on driver layer. It introduces the architecture of Win32 Driver Model(WDM), and analyzes the technology of IRP tracking from USB hub device in Windows system and implements to monitor the USB storage device by lower filter driver and file filter driver. It describes the total design of the security monitoring system of USB storage device.
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Computer Engineering. 2008, 34(8): 258-260. https://doi.org/10.3969/j.issn.1000-3428.2008.08.092Universal remote sensing image processing software is focused on remote sensing data preprocessing, and the work flow of monitoring and evaluation in ecological environment is complicated. To simplify the work, integrated with the technology of RS, GIS and GPS, the ecological environment monitoring and evaluation system embedded application module is researched and developped based on the RS and GIS, which is used in monitoring and assesses the severe flood disaster in Guangxi in June 2005, and satisfied monitoring results is achieved.
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Computer Engineering. 2008, 34(8): 261-263. https://doi.org/10.3969/j.issn.1000-3428.2008.08.093Knowledge sharing and cases retrieval are two principal issues in case-based decision support systems. For decision-making in maritime rescue command, this paper adopts Web Ontology Language to represent crisis situations and maritime rescue domain knowledge. Case-based planning process using description logics reasoning for maritime rescue is presented. Representation and reasoning on average situations and the corresponding rescue methods during rescuing grounding or stranding ships are exemplified. The result shows that classifying crisis situations in terms of semantic domain knowledge, with description logics reasoner, could in advance locate the specified case base to be retrieved and help to select reasonable rescue methods, which improve retrieval efficiency and practicability of rescue planning.
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Computer Engineering. 2008, 34(8): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2008.08.094Compact Peripheral Component Interconnect(CPCI) bus ruggedized computer is one of the most important military equipments. For the purpose of monitoring real-time online state and doing fault diagnosis during the equipment works, the architecture and working principle of its embedded fault diagnosis system is studied while considering the structure of CPCI bus computer. This paper designs a monitoring and management platform, and introduces the implementation schemes of its hardware and software, especially the realization of modules in software system. Some experiment results are given.
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Computer Engineering. 2008, 34(8): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2008.08.095This paper presents a Remote Disaster Tolerant System(RDTS) supporting hot archiving under the method of modularization. The system provides the transparency because of being implemented on device driver level. Another important advantage is the inductiveness of hot archiving, through which the data damaged problem caused by the virus and the users’ fault are solved, and also the service halting when archiving the mirror data. And the store space in the remote centre has been saved. The experimental results prove the superiority of the system.
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Computer Engineering. 2008, 34(8): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2008.08.096This paper provides a mechanism which depends on the ability of networking devices to analyze, detect, assess and response anomaly events in network operation. By collecting network traffic and classifying according to their behavior, a method is employed to mining the anomaly traffic behavior. The threat level to the network availability is computed by Bayesian model and the corresponding policies are generated to control this anomaly traffic automatically based on the result of threat evaluation. These policies are device-independent, and will be transformed to devices-dependent policy configuration commands by using XML techniques before they are deployed to a particular device. The mechanism given in this paper has capability to control network continuously and provides support to different networking equipments from different vendors.
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Computer Engineering. 2008, 34(8): 273-274. https://doi.org/10.3969/j.issn.1000-3428.2008.08.097When testing the IEEE Float Point(FP) arithmetic, there are so many corner cases among the complicated test cases that checking the correctness of FP instruction becomes especially difficult. Aiming at the weakness of directly random testing, thesis presents a method called Test using the Boundary Filter to generate test cases. Its ideas are modeling the boundary condition of the FP arithmetic, getting the solution of this modeling, constructing a filtering standard by the solution and filtering the operand for testing. Using this method to test C387L math coprocessor proves this method is more reliable.
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Computer Engineering. 2008, 34(8): 275-277. https://doi.org/10.3969/j.issn.1000-3428.2008.08.098After discussing the characteristic of the extended Event-driven Process Chain(eEPC) and Unified Modeling Language(UML) modeling language, this article proposes a novel integrated modeling method with eEPC and UML. This modeling method makes for the decision process in the prophase of modeling work, ensures the consistent understanding of the established models, and simplifies the transformation between models in the later stage of modeling work.
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Computer Engineering. 2008, 34(8): 278-280. https://doi.org/10.3969/j.issn.1000-3428.2008.08.099Guided by the theory of “visualization” of equipment support, this paper discusses the research content and construction goals of maintenance support resource visualization management platform based on equipment maintenance support of missile troops. The overall framework model of the system is brought forward. Its hardware, software and architecture are analyzed. Application of key techniques in the visualization management platform is explained.
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Computer Engineering. 2008, 34(8): 281-282. https://doi.org/10.3969/j.issn.1000-3428.2008.08.100This paper depicts an adaptive routing algorithms by initializing or maintaining routing table dynamically. The algorithms scans routing table to guarantee validity and reliability between the nodes, and finishes the process of communication by choosing the shortest path. The algorithms are applied to the project of wireless meter reading system based on ZigBee(2.4 GHz) to realize the communication remotely.
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Computer Engineering. 2008, 34(8): 283-第8期封. https://doi.org/10.3969/j.issn.1000-3428.2008.08.101This paper brings forward basic real-time factors of system evaluation based on the basic principle and operating mechanism of real-time operating system, and analyzes the affection of these factors on system performance. By the method of software stub, it does the factor testing between different systems, also gives a contrastive evaluation result of system real-time performance based on testing data.
2024
Volume 50 No 3
Volume 50 No 3
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428