05 August 2008, Volume 34 Issue 15
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Computer Engineering. 2008, 34(15): 1-3,35. https://doi.org/10.3969/j.issn.1000-3428.2008.15.001This paper mainly researches the problem of path planning in navigation of robot. The algorithm describes the environment of robot making use of grid division. In this environment, Ant Colony Optimization(ACO) is used to do path planning. The ACO is improved by the idea of Genetic Algorithm(GA), GAA algorithm is presented. Simulation results show that the method can effectively improve the speed of path searching, path optimizing and path smoothness.
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Computer Engineering. 2008, 34(15): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2008.15.002In the process of parallel recognition, many serial codes have no way to find a uniform decomposition result. Since data reorganization is unavoidable, how to design an effective dynamic decomposition algorithm is an issue to be researched. Based on the study of decomposition methods used in single loop nest and the representations of decomposition results, this paper proposes a dynamic decomposition algorithm which exploits coincidence linear data distribution results among loop nests. This algorithm also takes the structure and the control flows of serial programs into consideration for more accurate decomposition. It can be used in the process of parallelism decomposition for common serial codes. The computation partition and the data distribution result of serial codes are given by the algorithm.
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Computer Engineering. 2008, 34(15): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2008.15.003This paper presents a method of terminal data trusted transfer to solve the security problems, which are caused by data flowing in or out of terminals. According to “overall BLP model”, the data to flow in or out of terminals are checked, and only those matching the security policies can be transferred, which are encrypted or decrypted by TPM at the same time. It gives an implementation framework of the method, and analyzes its security. The method can insure that transferred data is confidential and controllable.
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Computer Engineering. 2008, 34(15): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2008.15.004In order to solve the problem of application porting on different platform in real-time embedded system, this paper designs a General Embedded System Service Platform(GSSP), which can run on different operating systems such as Vxworks, Windows, Linux. It centers on the two-level scheduling system of GSSP, carries on study in the two-level scheduling system, analyzes model and proposes feedback weight schedule method. It provides realization method and the conclusion of GSSP performance according to the tests.
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Computer Engineering. 2008, 34(15): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2008.15.005This paper investigates the state feedback H∞ control problem for a class of switched linear systems with state delay. Based on Lyapunov function approaches and convex combinations techniques, a sufficient condition for the existence of sub-controllers is presented, which is in the form of matrix inequalities. Both sub-controllers and switching strategy are designed. By using variable substitution method, the matrix inequalities are changed into Linear Matrix Inequalities(LMIs). A simulation example is given to solve the gain matrices of state feedback controllers.
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Computer Engineering. 2008, 34(15): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2008.15.006The NoC techniques changes on-chip communication in a SoC dramatically. As a result, current tracing techniques are not readily applicable to NoC-based systems where the transmission of traced data requires new concerns due to totally different communication mechanism. An in-depth analysis of ARM coresight trace architecture shows new challenges. It analyzes the difficulty of real time data transmission tracking in NoC, and proposes the solution which is verified by experimental simulations.
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Computer Engineering. 2008, 34(15): 19-21. https://doi.org/10.3969/j.issn.1000-3428.2008.15.007This paper proposes a novel airport Region of Interest(ROI) detection algorithm for large-scale spaceborne Synthetic Aperture Radar(SAR) image. The image is segmented via ICM algorithm according to the frame of MAP and the model of markov random field. The candidate ROIs are recorded by using object labeled algorithm. The parallel is detected by Hough transformation and the ones without parallel are removed. The histogram of projection of the candidate ROIs are calculated and the sample vector of candidate ROIs are constructed by five factors, including width and height of object, Ratio between Width and Height(RWH), Area Ratio between Object and Background(AROB) and Gray Mean between Object and Background(GMROB). Support Vector Machine(SVM) classifier is trained and applied to give the final result of ROI detection. Experiment with actual data indicates the algorithm is effective.
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Computer Engineering. 2008, 34(15): 22-24. https://doi.org/10.3969/j.issn.1000-3428.2008.15.008This paper proposes a new ship waves modeling method based on Kelvin waves and particle systems, which gives out 2-D ship waves model by using Kelvin waves theory, and extends the model from 2-D to 3-D by using particle systems. The bow wakes and stern wakes modeling methods using particle systems are proposed, which are based on the shape characteristics and stochastic movements of the two wakes. Experimental results show that the modeling methods are efficient and realistic in ship wakes simulation.
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Computer Engineering. 2008, 34(15): 25-27. https://doi.org/10.3969/j.issn.1000-3428.2008.15.009This paper studies the implementation and performance of the Proportional-Fair(PF) scheduling algorithm, which is affected by the technologies such as Packet-Division Multiple Access(PDMA). Simulation results show that by introducing PDMA and HARQ in 1xEV-DO Rev A, PF scheduling algorithm can obtain a satisfied forward throughput and efficiently meet the delay request of real-time traffics.
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Computer Engineering. 2008, 34(15): 28-30. https://doi.org/10.3969/j.issn.1000-3428.2008.15.010According to the relative stability of objects’ distribution and based on fixed grids, some leaf nodes representing the distribution of objects are selected as seed-nodes for new records to directly merge new records into seed-nodes without traversing R-tree. Some records which can not be merged into seed-nodes are chosen randomly as seed-records. Such records are grouped simply but effectively, so that they can be inserted into R-tree with the cost of inserting seed-nodes. The strategies pay attention to R-tree’s spatial clustering, and perform multiple inserting and deleting in one write-operation, decreasing the demand of writing and traversing R-tree. Experiments show that the strategies reduce the I/O cost of R-tree maintaining without affecting the query performance.
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Computer Engineering. 2008, 34(15): 31-32,4. https://doi.org/10.3969/j.issn.1000-3428.2008.15.011The paper draws out a model of soft-man characters in distance space, and designs a character vector space to give a quantity comparison of soft-men. Assuming that the differences between character vectors follow linear relationship, it sets up the equations. Because in most cases the equations are inconsistent linear equations, an approximate resolution to the equations is built. Three groups of experimental data are given to convince of the design, and prove it is reasonable to apply in practice.
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Computer Engineering. 2008, 34(15): 33-35. https://doi.org/10.3969/j.issn.1000-3428.2008.15.012The Rician noise introduced into the diffusion tensor images can bring serious impacts on tensor calculation and fiber tracking. To decrease the effects of the Rician noise, this paper proposes a multi-channel wavelet-based method to denoise multi-channel typed diffusion weighted images. To evaluate quantitatively the efficiency of the presented method in accounting for the Rician noise introduced into the DW images, the peak-to-peak signal-to-noise ratio metric is adopted. Based on the synthetic and real data, it calculates the apparent diffusion coefficient and tracks the fibers, makes comparisons between the presented model and the channel-by-channel smoothing method. Experimental results quantitatively and visually prove the better performance of the presented filter.
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Computer Engineering. 2008, 34(15): 36-38. https://doi.org/10.3969/j.issn.1000-3428.2008.15.013This paper proposes an extended expression method based on conic direction model considering distance relations. The corresponding construct way, queries processing against two steps including filter and refinement, and spatial reasoning way are developed. Empirical result proves that the method can efficiently fulfill direction and distance relations queries in huge datasets. It is simpler, more efficient and performs better compared with the traditional one.
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Computer Engineering. 2008, 34(15): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2008.15.014The available services discovery mechanisms have lower matching efficiency and precision because of lacking services filtrate mechanism and matching the services basic attributes, quality of services attributes by keywords. This paper puts forward a Web services filtrate method based on Latent Semantic Analysis(LSA). This method describes Web services basic attributes, quality attributes using tree structure, uses certain terms-frequency statistic method and weights method to build latent semantic analysis space, and builts advertising services index database and filtrates the Web services according to services request. Experimental results prove that this algorithm has higher precision and recall and improves services matching efficiency largely.
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Computer Engineering. 2008, 34(15): 42-43,5. https://doi.org/10.3969/j.issn.1000-3428.2008.15.015In order to bridge the "Information isolated island" in the enterprise information construction, it need to establish the subject database to realize the information sharing and the efficient communication between different departments. This paper introduces mathematical formulas in the plan of subject database and presents the algorithm based on entity affinity, makes the establishment of subject database more rigorous and standard. Moreover, it can be a guide for continuous correlated research and directs the transformation and reconstruction of the enterprise’s data environment.
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Computer Engineering. 2008, 34(15): 44-46. https://doi.org/10.3969/j.issn.1000-3428.2008.15.016Loop is the time-consuming part in program. The pipeline can accelerate its execution but needs too much computing resources. Due to limited resources, it’s impractical to pipeline the loop by hand in FPGA. In this paper, the loops are mapped automatically onto FPGA using software pipelining, and the pipeline scheduling under resource constraints is implemented. By exploring the whole or part combination space, a design which balances performance and area can be chosen.
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Computer Engineering. 2008, 34(15): 47-50. https://doi.org/10.3969/j.issn.1000-3428.2008.15.017By studying characteristics of duplicate XML data, this paper proposes an active machine learning method for a specific application, which is applied to glean transformation rules and matching rules, and accurately identify duplicate XML elements. Transfomation rules are used to eliminate the structural diversities among elements and matching rules are used to identify the relationships between parent and child nodes. In turn, during the detection phase an efficient hash filter algorithm is proposed to reduce computational complexity. Theory and experiment shows that the method can solve this problem efficiently and effectively.
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Computer Engineering. 2008, 34(15): 51-53. https://doi.org/10.3969/j.issn.1000-3428.2008.15.018A semantic distance between ontology concepts is defined to calculate the similarity between ontology concepts. Based on the similarity, a new semantic Web service matching algorithm is proposed. This algorithm abides by the grade of the classic OWL-S/UDDI algorithm and gives the precise matching between Web services. Experimental results show that the average precision of the new algorithm is 1.8 times than the OWL-S/UDDI algorithm and the average recall of the new algorithm is 1.4 times than the OWL-S/UDDI algorithm.
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Computer Engineering. 2008, 34(15): 54-56,5. https://doi.org/10.3969/j.issn.1000-3428.2008.15.019Based on the presentation of the demand analysis and overall architecture of the combined tactics training assessment system, the framework as well as hierarchical structure of the maneuver result assessment subsystem is mainly focused. It is divided into three parts in horizontal: main frame, action appraise module and arithmetic plug-in, and three layers also in vertical: data collection, data process, and grade report. The coupling extent between departments is reduced, and it is possible that various data collection means and effective analysis methods can be imported to the system. This solution can be referenced in a way.
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Computer Engineering. 2008, 34(15): 57-59. https://doi.org/10.3969/j.issn.1000-3428.2008.15.020Aiming at the heterogeneity problem between ontology, an ontology matching method based on Top-k mapping is put forward. This is an extension of existing methods. It takes similarity computation as a basis of the algorithm by calculating the similarity of two concepts at element and structure level. Moreover, it can generate k mapping simultaneously not one best mapping. Experimental shows that the method has advantages in the recall and precision, and excels GLUE in precision.
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Computer Engineering. 2008, 34(15): 60-62,6. https://doi.org/10.3969/j.issn.1000-3428.2008.15.021When performing some inconsistent decision tables, the obtained core-attributes are false by the core-computed method of Hu. Therefore, a definition of discernibility and a method of core-computation based on the constraint function are proposed, which correct the error of core solution from its imperfect for the definition of discernibility metrix in Hu’s method. Besides, the correctness of method is proved in theory and a quick core-computed algorithm is given. Extensive experimental study shows the time and space capability outperforms the core-computed method of Ye Dongyi.
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Computer Engineering. 2008, 34(15): 63-66. https://doi.org/10.3969/j.issn.1000-3428.2008.15.022In the sight of control, a hierarchical and distributed discovery model of resources is presented for application in industry. A deep study is made on the Grid-based Distributed Control System(GDCS) resource deploying policy with regard to resource requirement problems respectively in two different natures which is irrelevant and restrict to property, under the grid environment. As a result, deploying policy mathematical model is built up to meet various application requirements. As for resources deploying policy problem, which is irrelevant to property, an optimal solution can be worked out according to mathematical model since the deploying policy can be considered as a static matching process because of sufficient of the resources. However for the resource that is restrict to property, owing to the insufficient of the optional resources, the optimal solution can be obtained on the basis of mathematical model combined with heuristic algorithm.
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Computer Engineering. 2008, 34(15): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2008.15.023The real application systems comprise a large number of legacy application softwares with Graphical User Interfaces(GUIs), which emphasize the interactive mode between human and computer, and heavily depend on specific platforms. Challenges exist when sharing and collaborating them, which are essentially quite different from the ordinary resources sharing mechanism by the method of batch processing. Based on the China National Grid(CNGrid) platform and its Grid system software CNGrid GOS, this paper proposes and implementes a sharing system for GUI applications called GridShare. From the results of the prototype system, it shows that GridShare enables to achieve the goal of sharing and collaborative use of the legacy applications among multi-users in the Grid environment, and improves the utilization of grid resources, by employing the cross-domain security management and resource scheduling capabilities provided by the Grid platform.
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Computer Engineering. 2008, 34(15): 70-71,7. https://doi.org/10.3969/j.issn.1000-3428.2008.15.024Object-based Storage Device(OSD) is possible to be the bottleneck which restricts the system performance during a large number parallel access to the same OSD. This paper proposes an object storage system based on Net-RAID. Net-RAID has peripheral channel and network channel, and data directly transfer between Net-RAID and clients. The system has characteristics of object-based storage system, better capacity extendibility and performance.
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Computer Engineering. 2008, 34(15): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2008.15.025The existing studies focus a lot on the detection accuracy without considering efficiency, which leads a low performance in practical Online New Event Detection(ONED) domain. This paper analyzes the traditional ONED systems about the low performance limitation, and proposes an improved framework. A lot of storage and calculation overhead can be degraded based on the techniques of setting reasonable parameters and pre-filtering index linking tables, without decreasing detection accuracy. Experimental results demonstrate the enhanced performance of the ONED system.
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Computer Engineering. 2008, 34(15): 75-76,7. https://doi.org/10.3969/j.issn.1000-3428.2008.15.026In the field of tumor marker, detecting some markers together can improve the successful detection score. The cloud model has great advantages in interval definition of numerical attribute. By fuzzing the boundary of attribute and membership degree, the cloud model can express the real world well. This paper presents a combined markers detection discovery method to mine association and find out most valuable tumor markers in examination dataset. The experiments show 80% of the top 10 combined markers are fit for iatrical knowledge.
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Computer Engineering. 2008, 34(15): 77-79. https://doi.org/10.3969/j.issn.1000-3428.2008.15.027In the business enterprise, services are set up by different core technique, management system and geography information system. They distinguish with different saving format in the different systems of different geography positions, thus brings about great inconvenience for data’s comprehensive exploitation and data share. Aiming at that the GIS data share inconvenient present condition, making use of the superiority of XML and Java language, a kind of exploitation to connect a people’s technique is put forward. A GIS data integration frame by using technique of interface and network transport and XML related technique is presented. Make use of that frame model to carry out an emergency GIS system and connect the integration and the share of alarm system. Experiments verify the rationality of that frame, and express it can go with valid.
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Computer Engineering. 2008, 34(15): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2008.15.028Distance indexing and object search on an undirected weighted graph are important work while using an undirected weighted graph, which is also a key process while solving an actual problem. This article presents a distance indexing and object search method based on the undirected weighted graph. By distance category, signature encoding and compression, it implements well efficiency of indexing and search, reduces storage space. The article describes the modeling process of the method, introduces the process for handling the KNN search, and finally proves the superiority of efficiency by the method through comparative experiments.
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Computer Engineering. 2008, 34(15): 83-84,8. https://doi.org/10.3969/j.issn.1000-3428.2008.15.029In network information age, the traditional statistics and prediction methods have not been applicable to Web information collection and statistics anymore and owing to the requirements of information collection and statistics in special area are clearer than before, it makes the effectively directional information collection and statistics in special area and getting the corresponding predictive results become a more important research direction. This paper applies the technologies of Chinese word segmenting, Latent Semantic Analysis(LSA), semantic matching, and constructs a user interest model. In the mean time, it uses Service-Oriented Architecture(SOA) to design the Web information collection and statistics service, and validates the effect of the analysis of Web page gathering structure and unknown information, forecast for the relevance of Web page to control the information collection and statistics by concrete experiments.
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Computer Engineering. 2008, 34(15): 85-88. https://doi.org/10.3969/j.issn.1000-3428.2008.15.030As to short-term conflict problem of resources distribution shared by multiple projects, a novel market mechanism, called precedence cost queuing, is presented. It is different from the most market-based mechanisms based on equilibrium concepts and iterative adjustment of resources conflict. This paper presents a solution to individual resource-constrained local resource distributing in an optimal way, and the market mechanism also solves enterprise’s conflict problem of resources distribution. Due to the dynamic and distributed nature of the economy, it can achieve higher levels of flexibility, scalability and adaptability.
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Computer Engineering. 2008, 34(15): 89-91. https://doi.org/10.3969/j.issn.1000-3428.2008.15.031This paper researches the computer solving method of large-scale integer programming problem which is abstracted from enterprise business process management. A memory optimizing management method is proposed, which can memorize massive data efficiently. In the meanwhile, the classic algorithm of integer programming problem——branch & bound is studied, and an advanced algorithm of branch & bound by using the thought of artificial intelligence which can solve the large-scale integer programming problem rapidly is proposed.
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Computer Engineering. 2008, 34(15): 92-94. https://doi.org/10.3969/j.issn.1000-3428.2008.15.032The Radio Frequency Identification(RFID) middleware is an important part between the interrogator and the data process system in RFID systems, in which the RFID middleware can shield the difference of the various interrogators and supply a uniform interface for the development and implementation of the background data process system. After carefully researching the EPCglobal, an embedded RFID middleware system is designed and implemented. This paper introduces the architecture of the hardware and the framework of the software of the software, and demonstrates an implementation method for the embedded RFID middleware system. The embedded RFID middleware introduced in this paper has been used in RFID systems, and its feasibility is proved.
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Computer Engineering. 2008, 34(15): 95-96,1. https://doi.org/10.3969/j.issn.1000-3428.2008.15.033General search engine spiders can understand only common HTML tags, and can’t parser information from XML Web sites efficiently. This paper proposes a strategy of using XSL to help spiders to understand the structure of XML pages. Based on this strategy, a pure XML Website is set up, and a search engine based on Nutch which is able to parse XML Website content correctly is realized.
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Computer Engineering. 2008, 34(15): 97-99,1. https://doi.org/10.3969/j.issn.1000-3428.2008.15.034There are shortcomings of current Internet on aspects of the mobility and safety, and IP address is overloaded in semantics because it is used to represent both the location and the identity of a user. This paper analyzes several typical namespace improvement solutions that the identity and the position of a user separate mutually currently, compares its mobility, safety, and puts forward a mobile communication mechanism based on the universal network.
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Computer Engineering. 2008, 34(15): 100-101,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.035Classical Coverage-Preserving Nodes Scheduling Algorithm(CPNSS) of the Wireless Sensor Network(WSN) has the problems of low efficiency and energy non-balance. According to the problems, this paper proposes an improvement algorithm. It divides all the nodes into some dissimilar set, sets a priority-weight for each set by its average energy, and selects different sets to work according to their priority-weight, so as to achieve the balance of the node energy and prolong the life-time of the network. Experimental results prove its effectiveness.
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Computer Engineering. 2008, 34(15): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2008.15.036To study the space distribution and the transmission mode of network traffic in P2P network, this paper analyzes and evaluates the IP address geomapping technique. The advantages and the principle of the technique are present with comparing different network location acquirement techniques. A simple random sampling method is implemented to evaluated the most popular IP address geomapping data-base. Results show that the accuracy rate of province-level locations is 100%, and the accuracy rate of city-level locations can achieve 98.40%. It proves the reliability of the technique.
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Computer Engineering. 2008, 34(15): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2008.15.037In allusion to the mobility of the satellite network nodes and the characteristic of management domain dynamic partition in the satellite network, this paper proposes the login and logout mechanism of the satellite network dynamic management domain partition. In the mechanism, a ground branch-station sends the packets of login broadcasting to satellites in view. After receiving the packets, the SNMP agents on the satellites adopt link-delay test to respond. According to the mechanism, the SNMP primitives are extended. The definition of primitives, which followes RFC1157 criterion, can be encoded by the BER coding. The policy of the dynamic management domain partition on the basis of the login and logout mechanism, which is supported by the SNMP protocol, is realized by the design of the extended primitives.
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Computer Engineering. 2008, 34(15): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2008.15.038Point to Point Protocol(PPP) is a popular link layer protocol with the characteristic of high efficiency and authentication. This article offers a design based on virtual drive adaptive layer that focuses on the distributed designation of high-performance router. And it focuses on the realization of the PPP virtual drive module in RAL framework. The module offers the upper software well shield and simulation of the devices. So it satisfies the software-hardware independent design, improves the extension and maintenance of the system. Experimental result shows that the scheme is highly effective and stable. And it is easy for maintenance and migration.
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Computer Engineering. 2008, 34(15): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2008.15.039Aiming at the severe energy and computing resource constraints of Wireless Sensor Network(WSN), based on the analysis and study of data aggregation technology, a data aggregation model for WSN is proposed. Constructed data mining algorithm can be integrated in each sensor network node. Data dimension is reduced and data redundancy is eliminated after the raw-data is processed by data mining algorithm, and the communication traffic is decreased and the life of WSN is extended. Simulation results prove to be highly effective, so it is very valuable in practice.
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Computer Engineering. 2008, 34(15): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2008.15.040In micro mobility/wireless network environment, there are some real-time applications that are sensitive to delay. A step-by-step resource-reservation scheme for micro-mobility gives attention to the delay of RSVP handoff and the usage of network. The scheme updates route and reserves its resource in order to minimize the delay of RSVP handoff. After resource reservation of the updated route is accomplished, the data transmission of real-time application is temporarily resumed. During the data transmission, the temporary route is optimized in order to minimize the usage of link of the reserving route. As soon as the optimum route of RSVP is established, the data transmission is shifted from the temporary route to the optimum route, and the temporary route is torn down. After analyzing performance of the scheme, it is shown that the delay of RSVP handoff and the usage of network are synchronously improved.
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Computer Engineering. 2008, 34(15): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2008.15.041International Engineer Task Force(IETF) proposes a hierarchical mobile IPv6 protocol to provide mechanisms for handover performance. In the protocol, the Duplicate Address Detection(DAD) operations for the on-link care-of address and Regional Care-of Address(RCoA) greatly impair handover performance. The improved HMIPv6 is introduced to tentative address pool using link layer assistance. The tentative addresses are got from the pools directly, combined with the network prefix. Tentative address can be used as CoA, and therefore the DAD operations are avoided, so the handover delay can be greatly reduced.
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Computer Engineering. 2008, 34(15): 120-122. https://doi.org/10.3969/j.issn.1000-3428.2008.15.042To resolve the hard problem which is caused by using port hopping and data encryption in P2P traffic identification, a new system for identifying the P2P traffic is presented based on characteristic process by the relevant researching between host process and network traffic, and the identification of P2P traffic is realized by process matching on the client host. The system also has the ability to detect unknown P2P process. Experimental results show that the system has a good performance in P2P traffic identification.
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Computer Engineering. 2008, 34(15): 123-125. https://doi.org/10.3969/j.issn.1000-3428.2008.15.043This paper analyzes the problem of managing the users’ access to Access Convergence Router(ACR) resources in integrated network management system. View-based Access Control Model(VACM) in SNMPv3 framework and the Policy-Based Network Management(PBMN) are studied. A method of enforcing the policy-based management into the SNMPv3 framework is presented to enable the intelligent management for the users’ access to ACR resources.
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Computer Engineering. 2008, 34(15): 126-128. https://doi.org/10.3969/j.issn.1000-3428.2008.15.044Many IPTV companies provide their systems of authentication, authorization, accounting, but the systems are not compatible and their capability are not excellent for IPTV system. According to the theory of AAA and IPTV model, this paper gives a whole solution on AAA server based on IPTV. By using Diameter protocol, it optimizes the processes of authentication, authorization and accounting, and uses cache to resolve the capability bottle-neck of system. Simulation experiment verifies that it is effective.
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Computer Engineering. 2008, 34(15): 129-131. https://doi.org/10.3969/j.issn.1000-3428.2008.15.045This paper proposes a firewall-optimization method based on statistics analysis and anomaly detection. This method starts from the firewall rules matching probability, combines with anomaly detection, simplifies and optimizes the firewall rules. Experiments show that in ordinary circumstances, this method can simplify the firewall rules, and reduce the average number of rule comparisons required for firewall by 40%, greatly improving the performance.
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Computer Engineering. 2008, 34(15): 132-134,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.046Based on general access structure, this paper proposes a verifiable multi-secret sharing scheme. As the secret can be recovered with the shadows provided by participants and it is computationally difficult to get the sub-keys from the shadows, the sub-keys can be reused to share the multi-secret in this scheme. By verifying the information published by the dealer as well as the shadows of sub-keys provided by participants, this scheme can prevent both dealer and participant from cheating. The security of this scheme is the same as that of RSA cryptosystem and Shamir’s threshold scheme. It has higher efficiency compared with the previous schemes.
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Computer Engineering. 2008, 34(15): 135-137. https://doi.org/10.3969/j.issn.1000-3428.2008.15.047This paper points out the error of worm-anti-worm model and provides the revising model based on the law of worm propagation. For the different policy of anti worm, supplementary model for different anti policies of anti worm is provided respectively. Through numerical simulation, the influence for worm control of anti worm appearance time and the anti polices is analyzed. Results show that, for anti worm, the sooner for introduction, and the more comprehensive for the function of killing worm and restoring vulnerability, the better for the control of malicious worm.
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Computer Engineering. 2008, 34(15): 138-139,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.048This paper gives a new construction for (w, k, n) multi-receiver multi-fold authentication codes by using (n, w, q)-set and error-correcting codes. This construction makes probability of success in spoofing attack Pdu reach lower bound 1/q, and the maximum numbers of receivers and source states come to m(k, q) and m(w, q). Comparing m(k, q) and m(w, q) with q in the past, it shows that when k, w=2, the numbers improved is 1 or 2, when k, w≥q, the numbers improved is w-q+1. When q is a prime power, the lower bound improved is 1.
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Computer Engineering. 2008, 34(15): 140-141,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.049This paper presents a novel and efficient short signature scheme. It is proven to be existential unforgeable under adaptive chosen message attack. The security of the signature scheme is reduced to the security of the q-SDH problem in the standard model. This paper analyses the efficiency of the signature scheme. Compared with the latest signature schemes secure in the standard model, the signature scheme is more efficient and suitable to be applied in the actual world.
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Computer Engineering. 2008, 34(15): 142-143. https://doi.org/10.3969/j.issn.1000-3428.2008.15.050This paper analyzes the structure and transmission of IP packets in network communication, and points out that it doesn’t influence the routing by modifying partially the IP addresses. Based on this feature, it presents a new steganography scheme that maps the secret messages into IP addresses and replaces those of IP packets. It proves the feasibility, and the analysis of performance shows the security of the scheme.
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Computer Engineering. 2008, 34(15): 144-145,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.051Embedding ownership’s information as watermarking into relational database for its copyright protection is a new heated research on database security. A new relational database watermarking algorithm based on image is presented on the basis of transforming the least significant bits of numerical data. It uses labeling algorithm and vector iteration to embed watermarking into relational database. According to the statistic independent weights, it uses FastICA algorithm to pick up watermarking and original data. Experimental results show that in a blind-measure environment, the watermarking has good resistance to attacks.
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Computer Engineering. 2008, 34(15): 146-147,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.052Primitive elements and primitive polynomial play very important roles in the theory of the finite field. It is the premise of solving the problem about code sequences and searching the primitive elements can come down to searching primitive polynomial. This paper gives a new algorithm for searching primitive polynomials in the binary field making use of the algorithm for searching the minimal polynomial, and also gives out the minimal polynomial in the searching process. It shows the efficiency analysis of the algorithm.
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Computer Engineering. 2008, 34(15): 148-149,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.053In order to provide larger capacity of the hidden secret data and to maintain a good visual quality of stego-image, a novel steganographic method based on FCM and HVS is presented. The contrast and gradient sensitivity are used as feature vector, and by the way of FCM, the pixels are classified into the sensitive class and the less sensitive class. More secret data can be embedded in the pixels of less sensitive class, and less secret data can be embedded in the pixels of sensitive class. Experimental results show , compared with the four-sided side match method, the method hides much more information and maintains a good visual quality of stego-image as well.
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Computer Engineering. 2008, 34(15): 150-152. https://doi.org/10.3969/j.issn.1000-3428.2008.15.054Due to big size and high redundancy, real-time image encryption is becoming a problem. Partial encryption of image encrypts only the important parts of the compressed image data, thus it is a feasible scheme for encrypting images in real time. This paper presents a partial encryption of gray images compressed by Set Partitioning In Hierarchical Trees(SPIHT). The significance of different types of SPIHT coded bits is analyzed, the most significant bits for reconstructing images are selected and then encrypted using a stream cipher. Computer simulations results demonstrate that the proposed method can achieve image security by encrypting only small parts of the SPIHT coded image.
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Computer Engineering. 2008, 34(15): 153-155. https://doi.org/10.3969/j.issn.1000-3428.2008.15.055The fast implementation of elliptic curve cryptosystems relies on the efficient computation of scalar multiplication. On the curves with minimal two-torsion scalar multiplication based on point halving is more efficient than based on ordinary methods. A new method of point scalar multiplication based on MBNS using point halving is presented. This new method enhances scalar multiplication efficiently.
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Computer Engineering. 2008, 34(15): 156-158. https://doi.org/10.3969/j.issn.1000-3428.2008.15.056This paper simulates Distributed Denial of Service(DDoS) attack with NS2, and analyzes different samples of traffic based on wavelet. The relationship between sampling methods and estimation of Hurst parameter is presented. The analysis and experiments show that when selecting the traffic flow samples only in attacking period, the Hurst parameter will decrease, and when the sampling period includes non-attacking period, the Hurst parameter will increase.
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Computer Engineering. 2008, 34(15): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2008.15.057This paper analyzes AES and SMS4 algorithm and their reconfigurable characteristics, and introduces the architecture of system. The algorithm is implemented efficiently by using reconfigurable technology, parallel structure and pipeline. The comparison with traditional designs shows that the design can reduce the area cost greatly while the speed is guaranteed. It is suitable for security system with limited area and multiple requirements about cipher.
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Computer Engineering. 2008, 34(15): 162-163,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.058The lack of normative clock mechanism in PKI/PMI probably causes asynchronization, thus the infrastructures has hidden defects of usability and security. By analyzing the features of OCSP and PMI, this paper brings a clock synchronization technology based on OCSP middleware to solve the problem. An identity authentication and access control system with the technology can eliminate those defects above, and it neither overtasks the system markedly nor imports extra risk. It is applicable in most common digital certificate application.
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Computer Engineering. 2008, 34(15): 164-165. https://doi.org/10.3969/j.issn.1000-3428.2008.15.059This paper proposes a dynamic threshold secret sharing scheme. Each participant’s secret shadow is selected by the participant himself and the dealer need not deliver any secret information to each participant, so a secure channel between them is unnecessary. The shadows do not need to be changed when the shared secret is renewed, old participants are deleted or new participants are added. All these shadows are shorter than or as short as the shared secret. Each participant can share many secrets with other participants by holding only one shadow, and in the recovery phase, each participant is allowed to check whether another participant provides the true information. The scheme is based on the security of Shamir’s threshold scheme and the RSA cryptosystem. It is a computationally secure and efficient scheme.
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Computer Engineering. 2008, 34(15): 166-167. https://doi.org/10.3969/j.issn.1000-3428.2008.15.060This paper researches the design of matrix A for a class of S box. It gives necessary and sufficient condition whether a circular matrix is inverse, and shows the expression of S(X)=AXeb in GF(2n) has at least three terms if matrix A is chosen to be an inverse circular matrix in GF(2) which is not identity matrix. So it is appropriate to design A to be an inverse circular matrix in designing this class of S box. Choosing a proper inverse circular matrix A and making the polynomial expression of S(X)=AXeb in GF(2n) be the most terms to guarantee a good resistance against the interpolation attacks and higher order differentials cryptanalysis.
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Computer Engineering. 2008, 34(15): 168-169,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.061This paper presents a BP neural networks learning algorithm based on Ｍutation Particle Swam Optimization(MPSO) algorithm. The MPSO algorithm substitutes the traditional BP algorithm during the learning process in order to overcome that the traditional BP algorithm is easy to trap local minima and the PSO algorithm is precocious. The algorithm is applied to intrusion detection. The diagnostic results among BP neural networks based on different algorithms are compared by using KDD999 CPU dataset. The conclusion is that BP neural networks based on MPSO has faster convergence rate, minimum iterations, higher accuracy.
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Computer Engineering. 2008, 34(15): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2008.15.062The expert judgment risk response method used now in aircraft assembly project need to be improved for its subjectivity and complication. To make it more effective and reliable, this paper proposes an improved method that integrating neural network with framework reasoning. Based on frame theory, it stores experts’ experiences about risk response in the expert system repository by the rule that there are mapping relations between solutions and risk factors. The neural network is trained to obtain the knowledge in the form of weight. When using, it gets the response solution for the risk by reasoning and matching the output of the neural network with the knowledge in repository. It gives attention to the coupling of all risk factors to avoid the loss of information and also can simulate the expert thinking exactly to advance the project management ology level of aircraft assembly. This method has been replied in a certain airplane design project. Application illustrates the feasibility and validity of the method.
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Computer Engineering. 2008, 34(15): 173-175. https://doi.org/10.3969/j.issn.1000-3428.2008.15.063A novel method for designing the classifier of multi-dimensional data is proposed, which uses radar chart of multi-statistics to show multidimensional data and applies Fourier descriptors to recognize the radar chart. Different multi-dimensional data forms different radar chart and distinguishes different category. And Fourier descriptor takes as chart characteristic, by Fourier transform on the boundary curve of radar chart. Based on the improved Probabilistic Neural network(PNN), radar chart is recognised automatically. Experimental results show this method has better result of classification, classification precision is out approximately 8.25 percentage, compared with the traditional classifier.
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Computer Engineering. 2008, 34(15): 176-178. https://doi.org/10.3969/j.issn.1000-3428.2008.15.064An image fusion method based on Dual-Tree Complex Wavelet Transform(DT-CWT) is put forward in order to obtain better fusion effect. The DT-CWT is suitable to image fusion processing because of its shift invariance and directional selectivity. It is preferable to traditional Discrete Wavelet Transform(DWT). The fusion rules based on multi-scheme are also presented. The low frequency part employs local definition, and the high frequency parts employ local standard deviation after wavelet transform of source images. The experimental results of gray multi-focus images fusion and color multi-focus images fusion, and the statistics of evaluating index show that DT-CWT is superior to DWT and the proposed fusion rules are effective.
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Computer Engineering. 2008, 34(15): 179-181,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.065K-means algorithm is simple and fast, however its result is affected by the initial clustering center and easily falls into the local optimum. This paper combines Particle Swarm Optimization(PSO) and adjusting mechanism and the immune memory function of immune system to improve K-means algorithm, and proposes a clustering algorithm based on Immune Particle Swarm Optimization algorithm(IM-PSO-KMEANS). The experiments show that the IM-PSO-KMEANS algorithm overcomes the problems of K-means algorithm, and the results of clustering are better than algorithm based on PSO.
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Computer Engineering. 2008, 34(15): 182-184. https://doi.org/10.3969/j.issn.1000-3428.2008.15.066According to the characteristic of the pasture disease diagnosis and case diagnosis, combining the thought of Agent, this paper designs the structure based on multi-Agent, and analyzes the diagnosis process of this diagnosis system. It adopts the thought of multi-Agent to carry out the diagnosis process on the client. Users refer the diagnosis data, server receives data and analyzes the task, according the lever of case matching, the server confirms whether adopt the case diagnosis or adopt the common diagnosis, and gain the diagnosis result.
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Computer Engineering. 2008, 34(15): 185-186,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.067For a multifactor weather prediction problem, this paper constructs a new model of fuzzy neural network based on rough set. This model applies the rough set theory to reduce factors of weather and extract rules, the model of fuzzy neural network is built by these rules, and the initial parameters’ value of fuzzy neural networks is decided by the statistical parameters of rules and the result of discretization and the networks is trained by BP methods. The application example showi that this model is superior to the traditional one on fitting precision and training rate.
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Computer Engineering. 2008, 34(15): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2008.15.068This paper establishes the mathematical model of assignment problem. Assignment problem is translated into Traveling Salesman Problem(TSP), and Ant Colony Algorithm(ACA) is used to solve the TSP. ACA is an effective algorithm to solve combinatorial problems. Its searching speed is slow and it is easy to fall in local best as other evolutionary algorithm. In this paper, the dynamic pheromone updating ACA is proposed. Experimental results on TSP show that the algorithm has faster convergence speed and greater stability than classical ACA.
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Computer Engineering. 2008, 34(15): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2008.15.069Similarity measurement is an important step in image retrieval. In the general retrieval, distance measurement is the common method, and DP matching is one special form of distance measurement, using matching distance matrix. This paper analyzes the basic theory of DP matching, uses matching energy matrix instead of matching distance matrix, thereby gains the similarity of the query image and the sample image. It gains the character energy matching matrix according to the defined confine-points’ energies. Based on this algorithm and a conceived prototype, experimental result proves the algorithms is feasible.
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Computer Engineering. 2008, 34(15): 193-195. https://doi.org/10.3969/j.issn.1000-3428.2008.15.070Feature extraction techniques are widely employed in face recognition system to reduce the dimensionality of data and to enhance the discriminatory information. In this paper, a new feature extraction method——Weighted Maximum Margin Criterion(WMMC) is proposed, which is an extension of Maximum Margin Criterion(MMC). The inter-class and between-class scatter matrix are weighted separately by a weighting function. An efficient face recognition system is designed by using Discrete Wavelet Transform(DWT), Principal Component Analysis(PCA) and WMMC. Experimental results on ORL database show that the proposed algorithm improves the performance of face recognition significantly and achieves the highest recognition rate to 98.25%.
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Computer Engineering. 2008, 34(15): 196-198. https://doi.org/10.3969/j.issn.1000-3428.2008.15.071Wavelet and Partial Differential Equation(PDE) are the main methods in removing image noise. Image noise is removed by making use of discrete wavelet threshold transform. The expression form of PDE based on wavelet threshold is obtained. It adapts the method of fractional steps wavelet shrinkage for the solution of PDE based on above approach. It can receive better effect of image denoising and attain the purpose of preserving edge and smoothing noise. Experimental results show that the new method can obtain better effect and higher SNR than wavelet method.
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Computer Engineering. 2008, 34(15): 199-200,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.072A new particle swarm optimization based on select learning object probability is presented to improve the limited capability in escaping the local optima through modifying the velocity evolving formula. It uses particle’s fitness to choose better particle than the presented particle among swarm, and forms a candidate learning object set. Then, compute the selected probability of each particle among the candidate set, and form the learning object set, and use those information by weighting. In the presented algorithm, each particle can use the whole swarm information effectively and keep the diversity effectively. There Benchmark test function is selected. Experimental results demonstrate that the algorithm can improve optimizing performance effectively, and it can avoid getting struck at local optima effectively.
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Computer Engineering. 2008, 34(15): 201-204. https://doi.org/10.3969/j.issn.1000-3428.2008.15.073Offline Handwritten Chinese Character Recognition(HCCR) is one of the most difficult problems in pattern recognition, and various approaches are presented to recognize their different aspects. This paper describes the main techniques which mainly influence the performance of the recognition system, including the way of normalization, feature extraction, classification and recognition. It evaluates each technique and gives its conditions for correctly use, introduces the currently used Chinese character database.
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Computer Engineering. 2008, 34(15): 205-207,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.074A new detection method with confidence-based neural network and ROC analysis technology for determining threshold is proposed in this paper. With the scheme, the properties of spending pattern are converted to confidences. The abnormal detection model for credit card is established with algorithm of BP neural network. Test results show that the detection model is not dependent on a single card user and the introduction of ROC analysis technology ensures the accuracy and effectiveness of the abnormal detection. The model possesses preferable practicability and self-adaptability
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Computer Engineering. 2008, 34(15): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2008.15.075This paper advances a new data classification and filtering method based on rough set theory and Decision Tree SVM (DT_SVM) in allusion to the problem of Web information filtering. This method utilizes an improved heuristic algorithm of relative attribute reduction to eliminate redundancy, debase the spacial dimension of sample data, and train SVM by clustering integrated with DT_SVM, it can change multiclass problem into binary classification, and improve the training speed and the filtering precision. Experimental results demonstrate that the new algorithm gains a higher filtering recall and precision, manifests the algorithm’s advantage of rough set theory integrated with DT_SVM.
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Computer Engineering. 2008, 34(15): 211-213. https://doi.org/10.3969/j.issn.1000-3428.2008.15.076Aiming at the feature that transverse documents and vertical documents blend mostly in Chinese document layout, a menthod based on minimal spanning tree clustering is presented. Apply run_length smoothing algorithm on the document in horizontal direction, and vertical direction. Then, a pre_classification step is applied to the connected components generated after classifying run_length smoothing to body text into horizontally aligned and vertically aligned. Minimal spanning tree clustering algorithm is applied to the body text that are generated after pre_classification. Via experiment, the accurate rate reaches 97%. As is shown from the experiment, the method has a good effect on segmentation of Chinese documents.
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Computer Engineering. 2008, 34(15): 214-216. https://doi.org/10.3969/j.issn.1000-3428.2008.15.077Dual-Tree Complex Wavelet Transform(DT-CWT) can provide shift invariance and directional selectivity. In this paper, the histograms of the magnitude sub-bands produced by the DT-CWT six high-frequency sub-bands are analyzed. A novel texture feature based on the Gamma and Lognormal probability density is proposed, the Gamma and Lognormal parameters as the feature vector are chosen and the features using the technique of Edge Preserving Noise Smoothing Quadrant(EPNSQ) is smoothed. Furthermore, a texture segmentation algorithm is implemented by K-means clustering using the smoothed features. The experiments demonstrate the novelty and effectiveness of the proposed feature and segmentation algorithm with better boundary precision and region consistency.
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Computer Engineering. 2008, 34(15): 217-219,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.078In order to enhance the validity for the unstructured road recognition, this paper makes full use of the picture edge information after image classification and judgment of normalized color tristimulus coefficient to get the boundary data of the road through the image boundary scope, the boundary line tendency and the region classification. The following step should be tracking the path with Kalman Filter(KF), which solves the problem of road surface expansion, vagueness in road and un-road border area and shadow influence due to stone steps. The experimental result indicates that this simple and effective method adapts to every kind of different unstructured road and has certain robustness.
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Computer Engineering. 2008, 34(15): 220-222. https://doi.org/10.3969/j.issn.1000-3428.2008.15.079There is plenty high-quality information in Deep Web, but user has to input several keywords to search and reach the pages of Deep Web. Traditional crawlers cannot get to the Hidden Web pages because there are no direct links to pages of Deep Web. This paper presents a crawling strategy that can download the pages of Deep Web effectively. As the result of the only interface that Deep Web provides, the biggest challenge for Deep Web crawler is how to choose the best keywords to query effectively. This paper brings forward a new selecting method that based on the relevant weight of different keywords. The experiment shows that this method is efficient.
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Computer Engineering. 2008, 34(15): 223-225. https://doi.org/10.3969/j.issn.1000-3428.2008.15.080The parameters setting for Support Vector Machine(SVM) in a training process impacts on the classification accuracy. The selection problem of SVM parameters is considered as a compound optimization problem. Immune algorithm is an efficient random global optimization technique. It has nice performances such as avoiding local optimum, high precision solution, and quick convergence. This paper proposes an immune algorithm applied to model selection of SVM. This algorithm includes clonal selection, hyper-mutation and receptor editing. Experimental results indicate that this method significantly improves the classification accuracy of SVM.
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Computer Engineering. 2008, 34(15): 226-228. https://doi.org/10.3969/j.issn.1000-3428.2008.15.081Aiming at improving the measuring performance of Atomic Force Microscope(AFM), an open-structure controller is designed based on RTLinux with software and hardware constructed completely. The experimental results show that the RTLinux based control system is capable of controlling the AFM system. Thus more advanced control algorithms such as adaptive PID and control are expected to be implemented on this open platform and to enhance the scanning speed and resolution. Besides, this control platform can be extended to an open nano-manipulation platform which will faciliate future research on nano-manipulation.
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Computer Engineering. 2008, 34(15): 229-230,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.082Because of the high false acceptance rate and false alarm rate of IDS, this paper proposes a Bayesian Information Criterion(BIC) scoring Bayesian network model, which makes use of BIC scoring function and mountain-climb searching algorithm, and weakens the strong independence relation assumption of Naive Bayes. It offers an experimental study and analysis, which shows that this improved Bayes network model enhances the detection precision in recognition of DoS and Probe attacks
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Computer Engineering. 2008, 34(15): 231-233. https://doi.org/10.3969/j.issn.1000-3428.2008.15.083Document image analysis technology provides an effective tool for filtering junk mails in a graphic form. The aim of analyzing the color document image layout is to segment particular objects in the document image, so that the downstream steps can analyze and inspect whether there are special words in the document image. The network junk-mail-filter system can use this information to identify whether to filter the mail or not. Experiments on this system show that the method is efficient in inspecting different color and gray document images with different geometric structure. The proposed method has potential applications in document image information extraction and filtering.
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Computer Engineering. 2008, 34(15): 234-235,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.084The design of a graph data structure, the memory structure and the depth_first search traversing algorithm are proposed. This algorithm can make the graph implement traversing in DNA computer. In order to prove the feasibility of the method, an actual example is given out, which describes the implementation of the algorithm. On the basis of the experimental theory of bio-molecular, the algorithm is an effective and feasible method.
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Computer Engineering. 2008, 34(15): 236-237,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.085This paper proposes a dynamic performance optimal design method of micro-displacement sensor measurement and control system, and establishes mathematical model and correction model of system. With control system toolbox and optimal design toolbox of Matlab, the parameter optimization of correction model is completed, dynamic performance optimal design of measurement and control system is realized. Simulation show that optimal results are significant. Work frequency-band is expanded to improve dynamic performance of the system.
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Computer Engineering. 2008, 34(15): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2008.15.086The method of bus encoding is for cutting down the transition frequency. The Bus-Invert(B-I) coding is the most simple and practical. But the transition frequency reduction is not obviously during the sequential transfer. In this paper, it judges the type of sequential and non-sequential transfer and takes the method of asymptotic zero-transition activity encoding during the sequential transfer. Compared with the B-I coding method for the same program, it can cut down the transition frequency by 28.7% and area increasing by18 225µm2.
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Computer Engineering. 2008, 34(15): 241-243,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.087In agriculture greenhouse environmental controls, various equipments are used. The measurement and actuator layer in a greenhouse computer control system with hierarchical structure deals with the connection to the equipments and meters in detail. In the measurement and execution layer, the input and output interface of control system are defined as a variables table. The ECA rules are defined and used in the implementation of the data acquisition and control actions. And the complex control actions flow can be described as ECA set. The ECA-based measurement and execution layer encapsulates the hardware interface and makes the control system easily adapt to different equipments through configuration.
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Computer Engineering. 2008, 34(15): 244-246. https://doi.org/10.3969/j.issn.1000-3428.2008.15.088The architecture is the basis for multi-satellites scheduling system. This paper describes a novel distributed architecture for coordinating observations. The scheduling procedure is divided into control kernel and external modules to enable modeling all kinds of remote sensing satellites’ constraints. The control kernel processes the search and control strategy, the external modules is responsible for the operation related with single satellite. This architecture can make the multi-satellites scheduling system more extensible, maintainable and efficient in operation. Based on the taboo search algorithm, the relationship in control kernel with external modules is illustrated. The architecture serves as a strong support for further development of multi-satellites mission planning system.
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Computer Engineering. 2008, 34(15): 247-249. https://doi.org/10.3969/j.issn.1000-3428.2008.15.089This paper designs an aircraft-borne telephone conversation system based on RS485. The system completes transition from analog to digital in the aero communication, which using TDMA on the data bus. It Introduces scheme of the system, realizes real-time communication with multiple group, simultaneously completes to monitor the information of the control, alarms and records the voice of airborne.
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Computer Engineering. 2008, 34(15): 250-251,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.090This paper analyzes the principle and problems of the echo cancellation in digital video telephone system. According to these characteristics, a modified adaptive echo canceller based on sliding-window NLMS adaptive filtering algorithm and simplified nonlinear processor is presented. The structure of the proposed echo canceller as well as its composing modules is introduced. It shows how to accomplish the modified adaptive echo canceller on ARM 920T chip of ARM Co.. Simulation results show that the new system performs better than the original system in algorithm complexity and convergence rate. Objective tests are made using Composite Source Signals(CSS) according to ITU-T recommendation G.168. The performances meet with G.168 well.
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Computer Engineering. 2008, 34(15): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2008.15.091Based on research of JTAG standard and the ARM7TDMI debugging model, this paper proposes the hardware and software solution of debugging ARM7TDMI. The easy JTAG is introduced to control Test Access Port(TAP) by computer parallel port. The software is three-level structure and contains seven models. It discusses the level, model partition, and the definition and implementation of interfaces. Experimental results demonstrate that the software has good practicability and debuggability.
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Computer Engineering. 2008, 34(15): 255-258. https://doi.org/10.3969/j.issn.1000-3428.2008.15.092Fault-tolerant computer system can implement a good task-reliability, so it is used in flight control system broadly. This paper analyzes dual-computer fault-tolerant system, implements system hardware based on heart-beat line, cross-channel data link, and realizes modular hardware using enabling signal, self-loop circuits. System appoints master or slave computer utilizing identity-affirmant algorithm at start-up. Voting algorithm judges validity of data and detects fault. Synchronous algorithm synchronizes status, task and clock.
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Computer Engineering. 2008, 34(15): 259-260,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.093High frame frequency image processing at the present time has limitations, for software method is slow and lacks realtimeness, whereas special hardware has long cycle and bad flexibility. This paper presents a high frame frequency image hardware real-time processing system based on FPGA. The system adopts voting algorithm to implement synchronously image collection and operation, and reduce the amount of data that is needed to hold or handle. It exerts sufficiently the parallel characteristic of FPGA and observably improves speed of image processing, which has been applied successfully in real-time dynamic processing and analysis rail section of track inspection car.
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Computer Engineering. 2008, 34(15): 261-263,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.094In order to adapt agile alteration of examination and approval of business and improve system flexibility in enterprises, this paper proposes a custom model and its implementation scheme for examination and approval of business. The process of examination and approval is decomposed into several characteristics sets, such as objects, custom processes, roles, and so on. And the characteristics are defined by n-tuple of types, attributes and states. Dynamic configuration and real-time alteration of the examination and approval process can be realized by a characteristic matching algorithm. This scheme has been implemented actually during the grouping course of an enterprise and proved effectively to reduce 90% modification time caused by changing the examination and approval activities.
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Computer Engineering. 2008, 34(15): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2008.15.095This paper analyzes the requirement of anti-counterfeit for item level product and proposes an anti-counterfeit solution based on Radio Frequency Identification(RFID). A prototype system, combined the RFID with GPRS, is designed, through which the tea can be authenticated efficiently and conveniently. The limits and possible research field of RFID anti-counterfeit technology are discussed.
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Computer Engineering. 2008, 34(15): 267-268,. https://doi.org/10.3969/j.issn.1000-3428.2008.15.096This paper proposes an active Radio Frequency IDentification(RFID) system that can work at very low power consumption. It bases on the technology of sensor node and TinyOS operation system in sensor networks. Both high frequency and low frequency radio chips which are controlled by ATMega128 are used to decrease the energy consumption. TinyOS-based software architecture and the implementations of low frequency unit are presented.
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Computer Engineering. 2008, 34(15): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2008.15.099This paper analyzes the problem of sound track characteristic parameters’ extraction of speech signal. According to the disadvantage of self-correlation, an improved algorithm of the sound track characteristic parameters’ extraction of speech signal is presented to introduce its operational procession. In view of the high speed and suit for short term exploitation of FPGA, it designes the Finite State Machine so as to control the complicated operations and frequent visit to the registers for the FPGA design principles. The algorithm is implemented successfully into the single Altera Cyclone EP1C6 FPGA to fulfill the algorithm of the sound track characteristic parameters’ extraction of speech signal.
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Computer Engineering. 2008, 34(15): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2008.15.100To improve the utilization efficiency of the X86 PC Server and enhancing the reliability and safety of information systems in colleges and universities, this paper presents the design of the digital campus architecture based on virtualization. On this basis, it proposes virtualization technology and its classification, and discusses function design, structure and implementation of the virtual digital campus architecture. It presents how to carry out high reliability of system by prepare rules and polling mechanism. Pressure experiment which validates the practicability of the virtual digital campus architecture is done.
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Computer Engineering. 2008, 34(15): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2008.15.101The task of the first stage for the manufacture enterprise to stock by negotiation on the web is choosing suppliers. This paper focuses on the automation of supplier selecting by introducing Multi-Agent technology, presents the framework, evaluation system, evaluation method, functional structure of related agents and implements a prototype based on the designing of flow of the system. The manufacture Agent adoptes FIPA contract net protocol to obtain the offer from the suppliers, adoptes AHP to evaluate the suppliers and choose the suited ones. This method can select suppliers for negotiation automatically and help the manufacture to make initial quotation.
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Computer Engineering. 2008, 34(15): 283-封三. https://doi.org/10.3969/j.issn.1000-3428.2008.15.102The problem of how to allocate and share processor resources among multiple threads of multithreading processors has a direct effect on the performance of the processor. Four allocation models and the mechanism for implementation are brought out in this paper, and the balance of resource allocation is discussed. It points out that different allocation models and implementation mechanisms can be applied to different pipeline stage according to such factors as the character of the object application and pipeline stage, and so on, to allocate the processor resources reasonably.
2024
Volume 50 No 4
Volume 50 No 4
(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