05 February 2011, Volume 37 Issue 3
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Computer Engineering. 2011, 37(3): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2011.03.001Too much computation is the bottleneck in analysis of airborne antenna radiation. A parallel computing and rendering method is proposed to solve this problem. It proposes a semi-automatic algorithm to distill model’s skeleton based on space octree dividing and a equal triangles dividing method to solve the load balancing problem. It adopts sort-last parallel rendering framework and Binary-swap image composition method to solve parallel rendering problem. The algorithm is implemented in PC cluster system. Experimental results show this algorithm can drastically reduce the computing time and improve the rendering effect. It is benefit to apply this method in analysis of airborne antenna radiation.
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Computer Engineering. 2011, 37(3): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2011.03.002To improve the initivative and stability of Pan-Tilt-Zoom(PTZ) adjustment in visual system under constant illumination condition, Active Pan-Tilt-Zoom(APTZ) adjustment method based on Local particle Filtering Pre-Location(LFPL) under constant illumination condition is proposed. Target pre-location mehtod based on local particle filter is used to realize automatic estimation calibratiing for moving target. Initivative of PTZ adjusting is improved and nonlinear tracking problem can be settled. Dynamic selecting illumination-inviarants as filtering particles can overcome the affect of illumination varying and noise in target pre-location algorithm and robust of visual system is improved. Fuzzy control method is used to control pan and tilt to improve the stability of visual tracking system. The correctness and accuracy are tested by experiments. Long distance tracking for varying speed moving target using this method shows it is more stabile than the traditional method. Moving target racking under varying illumination and noise conditions shows ideal result.
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Computer Engineering. 2011, 37(3): 7-9,12. https://doi.org/10.3969/j.issn.1000-3428.2011.03.003A simultaneity optimization algorithm based on Immune Clone Selection(ICS) is proposed for searching optimal energy coefficient and contour of Parameter Active Contour Model(PACM). In the optimization problem, the solution is defined as a four dimensional vector which is composed of energy coefficients and contour, the objective function is defined as the combination of segmentation error rate and contour-point-shift mean. By testing to some representative images, it finds the algorithm is effective.
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Computer Engineering. 2011, 37(3): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2011.03.004DNA encoding constrained is researched. H-measure and similarity is the principal constrained for DNA sequence design. Continuity and GC Content is also another constrained. DNA sequence design is presented to solve the multi-objective optimization problem. Particle Swarm Optimization based on Cultural Algorithm(PSO-CA) is proposed to solve the DNA sequence design as a multi-objective optimization problem. Simulation results indicate the hybrid algorithm does well on searching efficiency and key stability for DNA sequence design problem.
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Computer Engineering. 2011, 37(3): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2011.03.005The paper uses the method of multi-Agent modeling and simulation based on REPAST platform to study the stability of the Peer production industry in the closed systems and the open systems. Analysis result shows that, in a closed system the number of Agents can not increase and external interference may expand through intelligent physical network topology, while in a open system Agents have life period and the numbers increase rapidly, the entire stabilized system will run at a low level, but does not appear collapsed.
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Computer Engineering. 2011, 37(3): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2011.03.006An algorithm which can improve the accuracy of vehicle license plate location using dyadic wavelet transform is presented. Based on texture feature of license plates and the characteristic of dyadic wavelet transform, the wavelet coefficients in vertical direction are retained. The proposed algorithm is suitable for the single-license and multi-license plate detection in the various illumination conditions with high accuracy. The performance of the proposed algorithm is tested on monitoring images obtained from the practical application. Experimental results show that the algorithm has better performance than Mallat’s on location precision, misdetection rate, and misjudgment rate.
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Computer Engineering. 2011, 37(3): 19-21,24. https://doi.org/10.3969/j.issn.1000-3428.2011.03.007For lip-reading system and authentication system based on lip, lip extraction is a very important preprocessing process. It affects the performance of application systems. The existing methods for lip extraction depend on the skin color of the people, and they are not effective for the image with tooth and brave. Aiming at this problem, based on the research of the diversity for different color space, this paper presents a lip extraction method using component of Lab color space, experimental results show it is effective and robust.
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Computer Engineering. 2011, 37(3): 22-24. https://doi.org/10.3969/j.issn.1000-3428.2011.03.008Aiming at the drawback that certainty decision rules and the uncertainty decision rules can not give the rejection, this paper proposes a new method to obtain rejective decision rules. By analyzing the measure factors of the decision rules, two kinds of reductions algorithms are defined, which can maintain the lower and upper approximation. A method of discernibility matrix is presented to obtain the reductions, from which the rejective decision rules can be simplified. Some numerical examples show the effectiveness and utility of the algorithm.
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Computer Engineering. 2011, 37(3): 25-26,29. https://doi.org/10.3969/j.issn.1000-3428.2011.03.009The object of former RSA fault attack is the software ran in hardware, such as smartcard. In order to research on fault attack against software implementation of RSA, the software implementation algorithm of Chinese Remain Theorem(CRT) is analyzed, the fault attack algorithm against OpenSSL’s implementation of RSA is proposed. It proposes an advanced attack scheme which only needs once faulty signature. Simulation results show that the proposed algorithm has feasibility to break the RSA’s signature key, and some countermeasures are presented to defend this kind of attack.
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Computer Engineering. 2011, 37(3): 27-29. https://doi.org/10.3969/j.issn.1000-3428.2011.03.010According to the re-authentication issue when the mobile node roams in the foreign network, this paper gives a fast re-authentication solution based on shared secret. Before the mobile node moves to the new foreign agent, a re-authentication key is distributed to the new foreign agent and the mobile node, and the two entities finish the authentication procedure using the shared key. It proves the security of authorization solution using BAN logic, and compares the performance of this solution with other related solution. Results show that the protocol is much more efficient than other current protocols.
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Computer Engineering. 2011, 37(3): 30-32. https://doi.org/10.3969/j.issn.1000-3428.2011.03.011This paper proposes a novel subgraph isomorphism verification algorithm named OES, which tries to find a subgraph isomorphism map by searching edge by edge in order to check whether a query graph is contained in some data graphs, and it can raise the verification efficiency by adjusting the edge order. A grading method for edges in query graph is provided, in which the lower score an edge gets, the higher pruning efficiency it can gain. So that good efficiency can be gained by verifying the edges in the order from higher grades to lower grades.
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Computer Engineering. 2011, 37(3): 33-35. https://doi.org/10.3969/j.issn.1000-3428.2011.03.012According to the weakness that traditional outlier data mining algorithms have lower efficiency in high-dimension space, from the viewpoint of outlier affecting orderliness of data set, this paper considers outlier mining as an optimization segmentation problem by using fractal theory. Based on the defining fractal outlier, Grassberger-Procaccia(GP) algorithm is used to calculate multi-fractal and general dimension. A greedy algorithm named FDOM is designed to solve the optimization problems of outlier mining. Experimental result shows that the algrithm is feasible to solve the problems of outlier mining.
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Computer Engineering. 2011, 37(3): 36-38. https://doi.org/10.3969/j.issn.1000-3428.2011.03.013Existing service discovery methods calculate service relevance based on statistical probability mostly, which is not able to precisely reveal the semantic relevance between query and service. Aiming at this shortage, this paper presents a Web service discovery method based on Vector Space Model(VSM). WordNet is adopted to build synonym vector. Service description is segmented to service theme and service content. A new function is provided to compute the relevance between query and service. Prototype system based on this method is also realized. Experimental result shows that this method has higher precision and recall with harmonic mean remaining in 0.6 above.
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Computer Engineering. 2011, 37(3): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2011.03.014Aiming at the condition that the limits of cluster memory lead to mass matrix can not import, this paper designs and realizes linear equation solving algorithm based on file splitting and Gaussian elimination. It continuously divides large-scale coefficient matrix files into multiple scale of controllable sub-files to storage and calculation, makes the server free ram small and has the better computation ability. Application result of ABEEMσπ model shows that when Altix3700 server is busy and the CPU share is high, the algorithm can also calculate the charge distribution of protein molecules.
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Computer Engineering. 2011, 37(3): 42-43,46. https://doi.org/10.3969/j.issn.1000-3428.2011.03.015This paper presents a new keyword search on graphs algorithm based on random walk with restart model and personalized PageRank algorithm. By combining vector space model and random walk model effectively, it can make the results match the query keywords as well as the structural information implied in the graph, which provides better searching results. Experimental result proves that the algorithm is effective.
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Computer Engineering. 2011, 37(3): 44-46. https://doi.org/10.3969/j.issn.1000-3428.2011.03.016This paper presents an extraction method of form Ajax information item. The method embeds JavaScript engine into the running programs which is independent of the browser, reconstructs the DOM and Ajax objects locally. It simulates the user operation in using the browser with the JavaScript engine tracking and executing the script to automatic gain form Ajax information item data. Experimental results show that the method can completely obtain form information of Deep Web query interface, and it can improve search accuracy.
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Computer Engineering. 2011, 37(3): 47-48. https://doi.org/10.3969/j.issn.1000-3428.2011.03.017This paper considers the differences of the individual contribution based on attribute set P classification in the tolerance relation, introduces the notion of approximate degree for the rough set. It defines a new entropy based on the consideration of both the elements belong to a set of Rp(x) and does not belong to Rp(x). On this basis, an attribute reduction algorithm based on approximate degree for incomplete information system is realized. Simulation results show that this algorithm has better reduction efficiency than IEARA algorithm.
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Computer Engineering. 2011, 37(3): 49-51,54. https://doi.org/10.3969/j.issn.1000-3428.2011.03.018
In this paper, Quality of Service(QoS) description is added to Web Service Description Language(WSDL). QoS certification center manages and quantifies the QoS attributes of services, which realizes the description of Web services’ QoS attributes. This paper designs a new service discovery mechanism. In the mechanism, Web services are selected by proxy service gateway, and there is a virtual service cache managing historical information of service requests. The mechanism reduces abundant service discovery and enhance the capability of services discovery. It uses an experiment system to validate the correctness and effectiveness of the mechanism.
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Computer Engineering. 2011, 37(3): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2011.03.019Aiming at the problem that dynamic semantics of the UML2.0 sequence diagram models is not able to formal description when it is used to model the interaction among objects, this paper puts forward an formalization method based on Temporal Description Logics(TDLs). TDLs is proposed by the temporal extending the Description Logics(DLs), which is the formal specification of the dynamic and temporal semantics. According to the novel UML2.0 interaction operators, the UML2.0 sequence diagram is separated into one or several maximal sequence fragments in order to get the TDLs semantic by formalizing the maximal sequence fragments and the interaction operators. Examples verify the feasibility of this method.
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Computer Engineering. 2011, 37(3): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2011.03.020For the problem of information isolated island exist in emergency, this paper makes use of Web service’s characteristics of cross-platform and loose coupling, introduces it into the emergency management field, specific to the different emergency services packaged by encapsulation server, published in the service registry, it uses the technology of business process management to manage and bind the services. The service recommendation strategy of the process nodes is specifically research based on emergency concept relevance, and an calculation method is proposed by extending and using semantic distance and matchmaking coefficient, and the experiment is illustrating the efficiency of this method.
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Computer Engineering. 2011, 37(3): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2011.03.021In order to improve the semantic description of items, and minify impact by mutual independence of terms in Vector Space Model (VSM), this paper proposes a phrase-based text representation. This model analyzes the relationship of the feature items, recognizes basic phrases by development of syntactic rules, and forms the related tree which contains feature items and head verb. It uses phrase-based to describe text instead of words in BOW, thereby the shortcoming of mutual independence is overcome. Experimental result indicates that the new approach improves the performance of the classifier, increases links between terms, and keeps classifying texts correctly, even if the number of feature items is small.
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Computer Engineering. 2011, 37(3): 61-63. https://doi.org/10.3969/j.issn.1000-3428.2011.03.022With the wide application of Internet and computer technology, online social networking service becomes one of the best means to keep contacts with old friends and to make new friends. However, there are still many shortages in Social Networking Services(SNS), such as user relationship deterioration and user loss. In order to solve these problems, this paper proposes a SNS website system based on “dormitory”. A module of user relationship mining is embedded to help users to get their potential friends in advance by weight and potential relationship updating. Experimental results show that this system achieves a good recommending accuracy.
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Computer Engineering. 2011, 37(3): 64-66,69. https://doi.org/10.3969/j.issn.1000-3428.2011.03.023For the problem of webpage content extraction, this paper presents a method based on section-factor to filter webpage and get the plain text paragraph. Each paragraph is regarded as a point in the two-dimensional space. The DBSCAN clustering algorithm can cluster these points to get the real content. This method has low complexity and does not depend on the site layout style, as well as has strong adaptability. Experiments are put on the news websites from domestic and international, and results show that for both Chinese and English news website has a high average accuracy and obvious effect.
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Computer Engineering. 2011, 37(3): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2011.03.024Aiming at many disadvantages of the FNR+-Tree model including excessive leaf node entries and a large number of insert operations, this paper proposes an improved model named FNR*-Tree. According to the number of moving objects, the district can be divided into urban and suburban areas, and on this basis, this paper proposes a method separately, which can index the object moving in urban and suburban areas and a new approach in. Analysis results show that the model has good query efficiency and query accuracy.
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Computer Engineering. 2011, 37(3): 70-71,74. https://doi.org/10.3969/j.issn.1000-3428.2011.03.025Aiming at the problem that traditional collaborative filtering algorithms generally exist highly sparse and extensibility, this paper proposes a method of virtual model of users clustering to improve collaborative filtering algorithm. By clustering users space, it gets proper clustering granular and recommendation automatically. Experimental results show that the algorithm is obviously effective, and improves prediction accuracy and stability compared with traditional collaborative filtering.
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Computer Engineering. 2011, 37(3): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2011.03.026This paper realizes a ULTPR-tree for moving objects with frequent updates, which is based on TPR-tree by adding a memory-based Update Log(UL). It uses grouping method to delete the records of moving objects in bulk, which decreases the cost of deletion maintenance of ULTPR-tree. Theoretical analysis and experimental results show that the update performance of ULTPR-tree outperforms TPR-tree and HTPR-tree.
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Computer Engineering. 2011, 37(3): 75-76,79. https://doi.org/10.3969/j.issn.1000-3428.2011.03.027This paper researches the best-relay selection scheme based on Amplify-and-Forward(AF) protocol in Multiple Input Multiple Output(MIMO) relay system, derives the closed-form expressions for the outage probability and average channel capacity, simulates the outage probability and the average channel capacity with different relays. Result shows that the scheme can reduce the outage probability effectively, and the average channel capacity of best-relay selection scheme outperforms the direct transmission scheme as the number of relays increases.
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Computer Engineering. 2011, 37(3): 77-79. https://doi.org/10.3969/j.issn.1000-3428.2011.03.028Based on studying the conventional QRD-M algorithm for Multi-Input-Multi-Output(MIMO) signal detection, an improved QR-Decomposition-based M detection(QRD-M) algorithm is proposed. Through arranging accumulative measurement of branches and setting termination threshold, the number of branches searched decreases in the proposed algorithm reasonably. Simulation results manifest that when SNR is 10 dB, the scheme of modulation is 16QAM and using 4×4 antenna configurations, the improved algorithm can get 30% reduction in computational complexity compared with the conventional QRD-M algorithm without losing detection performance.
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Computer Engineering. 2011, 37(3): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2011.03.029This paper researches the relation of maximum throughput between nearby nodes and back-off slots. When back-off slot is small, the rise of back-off slot paramets makes the three-way handshaking delay shorten, so it can get more maximum throughput between nearby nodes. However, when the back-off slot is large, the rise of back-off slot paramets increases the delay of control part, which decreases maximum throughput between nearby nodes. Simulation result is corresponding with theory analysis.
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Computer Engineering. 2011, 37(3): 83-86. https://doi.org/10.3969/j.issn.1000-3428.2011.03.030Aiming at heterogeneous characteristics of Wireless Sensor Network(WSN), an energy-efficient distributed clustering algorithm called EEDC is proposed. It chooses sensor nodes with high residual energy as tentative cluster heads to participate in the final cluster head competition. EEDC elects tentative cluster heads to be final cluster heads by a novel probability based on the intra-cluster communication cost. The cluster heads generated by EEDC are nodes with high residual energy and low intra-cluster communication cost. Theoretical analysis and simulation results show that the protocol can obtain good cluster head distribution and prolong the network lifetime significantly.
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Computer Engineering. 2011, 37(3): 87-89,92. https://doi.org/10.3969/j.issn.1000-3428.2011.03.031Broadcast and multicast application based on TCP/IP protocol in link layer and realization of virtual network device, for multi- processors environment, based on shared memory under VxWorks are introduced. A contrast of physical and link layers is made between the Ethernet and the virtual networks device upon broadcast and multicast. The virtual network device’s drive for VxWorks with its operation on the broadcast and multicast is analyzed. And an optimized scheme on broadcast and multicast on multi-Longson 2E processors parallel signal processing mainboard pointed to virtual network device’s physical character is designed and realized which is based on pipeline thinking. The real time performance, balance of the net node load and the transmission efficiency are improved greatly.
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Computer Engineering. 2011, 37(3): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2011.03.032Taking into account the influence of the non-stationary interference in other channels and stationary noises, a constrained adaptive time delay estimation algorithm based on cyclostationarity is proposed. This algorithm is based on the cyclostationarity of the signals, it can refrain the interference of disturbances and noises effectively, and it is useful when the noises are spatially correlated. It can attain time delay which is not an integer multiple of sampling interval accurately and directly in low signal-to-noise ratio environment, and its computation load is much smaller than that of interpolation method. Simulation results demonstrate the effectiveness of the algorithm.
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Computer Engineering. 2011, 37(3): 93-95. https://doi.org/10.3969/j.issn.1000-3428.2011.03.033Aggregated multicast is a new focused solution to that problem of multicast state scalability, but current aggregated multicast algorithms and protocols lack load balance mechanism of network flows. An aggregated multicast protocol based on load balance, AMPLB is proposed. Simulation results demonstrate that this protocol keeps aggregation performance when balances network flow distribution and decreases the risk of congestion so as to improve the performance of large-scale multicast network.
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Computer Engineering. 2011, 37(3): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2011.03.034This paper proposes a new Churn-resistance strategy based on Chord using relationship between near and far neighbors in the overlay network to modify the node routing pointer table. At the same time, the route processing parallelism and the maintenance strategy of Churn for each peer are modified. Experimental results show that the modified network reduces the network maintenance cost in the network environment under Churn, and improves Churn-resistant ability of the system and successful rate of search effectively when the search routing source node and destination node are determined.
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Computer Engineering. 2011, 37(3): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2011.03.035
By analyzing channel model mechanism of Markov stochastic process, the channel modeling scheme of 802.11n is studied and the simulation module of 802.11n channel model D is implemented in NS2 software environment based on corresponding Look Up Table(LUT) which includes Channel Capacity(CC), Packet Error Rate(PER) and Signal to Noise Ratio(SNR). It verifies the accuracy of this module through comparing simulation results with TGn standard model. The module provides efficient physical layer channel simulation foundation for the research and improvement of the 802.11n protocol.
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Computer Engineering. 2011, 37(3): 102-104,107. https://doi.org/10.3969/j.issn.1000-3428.2011.03.036
In order to avoid the broadcasting storm caused by traverse routing in Pub/Sub system, this paper introduces the concept of immunity of epidemic dynamics model to traverse routing and proposes a degree-based immunity traverse routing strategy based on scale-free networks for Pub/Sub system. In particular, the paper uses immunity nodes to control the direction of message flow, avoids traversing the agents and reduces load, and the selection of immunity nodes is based on the degree threshold δ. Simulation shows that the immunity routing can reduce the network load and increase the system’s scalability compared with Flooding and Epidemic.
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Computer Engineering. 2011, 37(3): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2011.03.037In order to improve communication system performance in wireless fading channel, this paper proposes LDPC coded Signal Space Diversity(LDPC-SSD) with precoding system. The signal space diversity rotation matrix is considered as an encoder with code rate equal to 1. In this system, a precoder is added before the signal space diversity matrix. At the same time, three pre-encoder design criteria are given. The pre-encoded LDPC-SSD system is simulated in wireless fading channel. Simulation results show that the proposed scheme has better performance than those without pre-encoded LDPC-SSD system in wireless fading channel.
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Computer Engineering. 2011, 37(3): 108-110,113. https://doi.org/10.3969/j.issn.1000-3428.2011.03.038Differential analysis is one of the most effective way to attack iterative code, it can be used to attack cryptographic system which is the iteration of a fixed round function. This paper describes the differential analysis which is used in Hash function HAVAL-128, and gives the method of choosing the messages difference, determining the path difference, deriving the sufficient conditions which ensure the establishment of differential path. It details the interpretation of the theoretical basis for using differential analysis.
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Computer Engineering. 2011, 37(3): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2011.03.039Based on analyzing the structure character of Elliptic Curve Cryptography(ECC) algorithms, the representative operation is selected. This paper has a research on the parallelism among the operation. A solution for efficient cryptographic processing through two multiplication modules and two addition/subtraction modules are proposed. A Very Long Instruction Word(VLIW) architecture of ECC coprocessor with specific instruction set is also presented. Experimental result shows that this co-processor has tradeoff between high performance and flexibility.
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Computer Engineering. 2011, 37(3): 114-115,118. https://doi.org/10.3969/j.issn.1000-3428.2011.03.040The combiner generator with memories can improve the algebraic degree and the order of correlation immunity, it is one of important keystreams. From its probability model, the sufficiency and necessary condition to provide k orders of correlation immunity is presented. The square summation of correlation coefficient between the output sequences and the input sequences is calculated, and common formula of calculating the square summation is given. Analysis result shows that the combiner generator with memories satisfying some conditions can preferably resist correlation attack.
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Computer Engineering. 2011, 37(3): 116-118. https://doi.org/10.3969/j.issn.1000-3428.2011.03.041This paper presents a signature with shared verification scheme based on verifiable multi-secret sharing. The scheme effecitively overcomes the deficiencies of the previous schemes in terms of security. In the process of signature verification, validation group can prevent some members providing the faulted information. This can make verification failure. Because the scheme uses verifiable multi-secret sharing, it can verify many signatures when it makes once multi-secret sharing. It has higher efficiency compared with the previous schemes.
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Computer Engineering. 2011, 37(3): 119-120,123. https://doi.org/10.3969/j.issn.1000-3428.2011.03.042This paper proves the probability distribution of the first output byte which is not uniform when the inner state is not uniform proved by fluhrer after the KSA of RC4, its probability equal to 186 is 0.003 892 5. Using the obtained results, the paper proposes a new and practical distinguishing attack on RC4. The data complexity of the new attack is 224 Byte and the distinguishing advantage is 0.84. Experimental result shows the validity of the distinguishing attack.
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Computer Engineering. 2011, 37(3): 121-123. https://doi.org/10.3969/j.issn.1000-3428.2011.03.043In the survivability storage systems, security and efficiency are two quite crucial factors. For the general storage scheme can not satisfy the requirements of these two cases at the same time, this paper achieves a compromise between security and efficiency by using the server muster and combining with replication and secret sharing methods. In the scheme, each visitor can choose the best way to access the data according to geographic location and every server group can also increase or delete nodes without damaging the scheme functions. The scheme not only has high security and efficiency, but also improves the flexibility. It has very high practical value.
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Computer Engineering. 2011, 37(3): 124-125,128. https://doi.org/10.3969/j.issn.1000-3428.2011.03.044This paper presents a verifiable multi-secret sharing scheme based on elliptic curves. In the scheme each participant chooses her/his shadow by her/himself, so the system does not need a secure channel. It is a multi-use scheme, which can share several secrets in one secret sharing process. The security of the proposed scheme is based on the security of the Elliptic Curve RSA cryptosystem(ECRSA) and the intractability of the Elliptic Curve Discrete Logarithm Problem(ECDLP).
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Computer Engineering. 2011, 37(3): 126-128. https://doi.org/10.3969/j.issn.1000-3428.2011.03.045This paper puts forward a secure scheme to establish the session key between communication parties by use of binary symmetric polynomials, considering the hierarchical Wireless Sensor Networks(WSN) update. This scheme can guarantee the confidentiality and integrity of the message transmission, and can effectively resist the attacker’s illegal tampering, replacement and replay to the message. Moreover, this scheme supports the session key update between communication parties and can enhance the authentication to the node identity so as to prevent the spoofing attack of the illegal nodes. Analysis shows that this scheme is more secure than others, and has reasonableness of cost and efficiency.
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Computer Engineering. 2011, 37(3): 129-131. https://doi.org/10.3969/j.issn.1000-3428.2011.03.046A SIR/WS model of malware propagation in Wireless Sensor Network(WSN) is proposed after the model of WSN is obtained. Based on IEEE 802.15.4 and epidemic theories, the model considers the mechanism of saving energy and describes the broadcasting process of malware in the WSN. It is found that the propagation of malware in the WSN can be restrained by increasing the recovery rate and decreasing the infection rate. Simulation results show that the model works well.
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Computer Engineering. 2011, 37(3): 132-133,136. https://doi.org/10.3969/j.issn.1000-3428.2011.03.047Group key agreement protocol is an important mechanism to ensure the security of subsequent communication. This paper researches a password-based Group Key Agreement(GKA) protocol proposed by Byun and Lee and finds that this protocol is vulnerable to undetectable on-line dictionary attacks. Based on this finding, it improves this protocol and presents a new GKA protocol. Security analysis shows that the protocol is resistant to the attacks available for password-based GKA protocols.
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Computer Engineering. 2011, 37(3): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2011.03.048This paper proposes an improved AdaBoost algorithm aiming at intrusion detection according to the features of cascade structure. The improved AdaBoost adjusts the method of acquire parameters, the initial weights and decision threshold so that the weighted parameters of weak classifiers are determined by not only the error rates, but also their abilities to recognize the abnormal samples. The algorithm can decrease the false alarm ratio of classifiers, so it is more adaptive to the intrusion detection. The validity of the improved AdaBoost algorithm is proved by the following simulation experiment.
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Computer Engineering. 2011, 37(3): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2011.03.049The study on trust relationship among grid entities is the hot point of grid security because of the security problem resulting from the dynamics and the uncertainty of grid technology. According to the characteristic of grid technology, an improved layered trust model that is based on domain is presented under the study of the available trust relationship. This model is used to deal with trust relations among entities in the grid environment. The model takes different ways to deal with trust relation in and between domains, the update mechanism of the trust value and the attenuation factor of time. A preferable performance in availability of the model is indicated through analysis and experiment simulation, and it is the efficient supplement to trust models in grid.
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Computer Engineering. 2011, 37(3): 140-142,148. https://doi.org/10.3969/j.issn.1000-3428.2011.03.050Based on the analysis of the routing protocol of Low Energy Adaptive Clustering Hierarchy(LEACH), it starts to the view of the offensive and defensive in the routing security, expatiates the existing principle of the routing attack detailedly, and proposes a key management of key agreement based on identification authentication to keep away the attack. At the same time, it uses the secret sharing techniques to prevent key points attacking, also provides a proposal tosecure routing of WSN on the design and implementation.
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Computer Engineering. 2011, 37(3): 143-145,148. https://doi.org/10.3969/j.issn.1000-3428.2011.03.051On the basis of Attribute-Based Encryption(ABE), and combining with the bilinear pairings on elliptic curves, an Attribute-Based Encryption with Identity-Based Signature(ABE-IBS) scheme is proposed. Based on the scheme, one efficient signature-encryption scheme for Wireless Sensor Network(WSN) is presented. Analysis shows that proposed scheme has the low complexity and storage requirement, and can improve the security of WSN.
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Computer Engineering. 2011, 37(3): 146-148. https://doi.org/10.3969/j.issn.1000-3428.2011.03.052This paper presents a new clock-control model which is a combined model of cumulative function and the clock-control generator. This new edited sequence’s data rate, period, linear complexity, 1-complexity of weight are discussed. It is shown that the editing sequence has pseudo-randomness of high data rate, large period, large linear complexity and so on. This model can be simple put into practice and promotion. So it is a good pseudo-random sequence suitable for practical implementation of signal code systems.
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Computer Engineering. 2011, 37(3): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2011.03.053Rao-Blackwellised Particle Filtering(RBPF) is a class of particle filter. A particular nonlinear radar target tracking problem is analyzed in detail, this kind of problem is often dealt with linearization and it is failed when correlation between measurement noise is too big. In this simulation test, multi-weight of RBPF is discussed and a doable way is proposed, the performance of RBPF under much correlation of noise is analyzed, relative estimate error of RBPF is also discussed when time processes.
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Computer Engineering. 2011, 37(3): 152-154,157. https://doi.org/10.3969/j.issn.1000-3428.2011.03.054The main idea and the key point of LebMeasure algorithm, HSO algorithm, HSO+MWW algorithm and HKMP algorithm are introduced. The performance of the algorithms is compared on the different data set. Experimental results show that the performance of HSO+MWW is better than that of HSO for all of the fronts. For HKMP and HSO, it consists with the theory that the performance of the former is better than that of the latter when the number of the processed point exceeds some value. For the random front and the discontinuous front, the performance of HSO+MWW is worse than that of HKMP when the number of the processed point exceeds some value. But for the spherical front and the degenerate front, the performance of HSO+MWW is better than that of HKMP.
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Computer Engineering. 2011, 37(3): 155-157. https://doi.org/10.3969/j.issn.1000-3428.2011.03.055The introduction of chaos Genetic Algorithm(GA) to optimize multi-objective QoS multicast routing, is to overcome the convergence of logistic map isn’t fast enough, will affect the efficiency of the tradition chaos genetic algorithm. A new kind of chaos GA based on Tent map chaos GA is introduced to the solving of QoS multicast routing in this paper. The excellent interval uniform search capability of tent map is used, chaos optimization again to individuals which are selected out of the genetic optimization, optimizing the highest fitness individuals to crossover and mutation, to ensure a sufficient number of the next generation, and algorithm will not fall into premature. Simulation results show the algorithm is better than Logistic chaos GA, which is effective to improve the search efficiency, speed up the convergence and make it more stable.
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Computer Engineering. 2011, 37(3): 158-160. https://doi.org/10.3969/j.issn.1000-3428.2011.03.056In order to reduce the maintenance cost of resource index table of the mobile nodes in the MP2P network, use the edge resource of network enough, and parallel process the mobile task of network, this paper proposes the resource interactive technology based on Genetic Algorithm(GA) to make sure that the mobile node can adapt the change of routing actively during the resource interaction, and can find out the changing optimal route with lower cost. Experimental results show that this method makes it possible to obtain mobile resource efficiently and dynamically.
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Computer Engineering. 2011, 37(3): 161-162. https://doi.org/10.3969/j.issn.1000-3428.2011.03.057A method to detect ships with ship-borne radar images is presented in this paper. It adds multiple consecutive radar images, and estimates the probability distribution of the radar backscattering of sea clutter with the Probabilistic Neural Networks(PNN) model. It determines the threshold by applying the Constant False Alarm Rate(CFAR) model and removes the false alarm according to the connected area size of any probable object in the binary image obtained by thresholding. The temporal sequences of X-band ship-borne radar images are used to test the performance of the proposed method. The obtained results show that the detection precision reaches up to 89.5%.
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Computer Engineering. 2011, 37(3): 163-165. https://doi.org/10.3969/j.issn.1000-3428.2011.03.058A Cognitive Radio(CR) cross-layer optimization architecture based on co-evolutionary theory and cognitive decision engine based on co-evolutionary Particle Swarm Optimization(PSO) algorithm are proposed in this paper. For improving the convergence rate and efficiency, the proposed algorithm reduces the high dimensional particle to low dimensional particle by co-evolutionary theory. Simulation results for multi-carrier system show that the proposed cognitive decision engine in convergence rate and operational efficiency are better than the cognitive decision engine based on basic particle swarm optimization and based on quantum genetic.
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Computer Engineering. 2011, 37(3): 166-168. https://doi.org/10.3969/j.issn.1000-3428.2011.03.059This paper presents a method called Sub-pattern Class-Augmented Principal Component Analysis(SpCAPCA) and its application in face recognition. The original images are divided into several sub-patterns by the presented approach. The SpCAPCA method is applied to the sub-patterns obtained from the previous step. The obtained features are combined according to a certain order. The dimension of the original images can be reduced. This approach can not only extract the local features of the images effectively, but also adapt the complicated illumination conditions. Experimental results show that the proposed SpCAPCA algorithm achieves better performance than other feature extraction methods, such as CAPCA, SpPCA.
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Computer Engineering. 2011, 37(3): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2011.03.060By analyzing the principles of various clustering methods and existing problems when current clustering methods are used in background extraction, this paper proposes a background extraction method based on adaptive on-line clustering. This method adopts adaptively dynamic thresholds to do on-line clustering on video to adaptively extract background images from a variety of videos without setting any parameters. Experimental results show that this method has a good adaptability, and is capable of extracting excellent background image, and has good robustness for various videos.
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Computer Engineering. 2011, 37(3): 172-174. https://doi.org/10.3969/j.issn.1000-3428.2011.03.061According to a large amount of network traffic data collected from the actual network, this paper proposes a new modified Elman neural network named Seasonal Input Multilayer Feedback Elman(SIMF Elman). Chaos searching is introduced into model training and uses the ergodicity of the Tent map to search the chaotic variables. Thus the data redundancy is reduced and local optimum problem is solved. Experimental results show that new model and strategy can improve the network training speed and forecast accuracy of network traffic.
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Computer Engineering. 2011, 37(3): 175-177,182. https://doi.org/10.3969/j.issn.1000-3428.2011.03.062In order to provide the basis for the management of allocating orders in Horizontal Manufacturing Collaborative Alliance(HMCA), this paper designs an algorithm named Multi-population Binary Ant Colony Algorithm with Hybrid Behaviors(MPBAHB) to minimize the comprehensive cost and balance the production loads among the selected manufacturing enterprises. Based on Binary Ant Colony Algorithm (BACA), two strategies of zoning and environmental evaluation/reward are introduced to conquer the drawback of original BACA of difficult to get multiple solutions. And a searching behavior named “central disturbing” is introduced to BACA, so as to strengthen the searching ability. Experimental results prove that the algorithm can get better solutions while keeping the distribution of Pareto front.
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Computer Engineering. 2011, 37(3): 178-179,182. https://doi.org/10.3969/j.issn.1000-3428.2011.03.063For most speech enhancement process, the accuracy of the a priori SNR and the background noise estimation has great influence. This paper derives traditional MMSE-LSA algorithm based on noncausal a priori SNR estimation. In contrast to the LSA algorithm, it introduces noncausal estimation for the a priori SNR, and utilizes smoothing parameters to change the value of noise spectral which can adaptively adjust to the noise environment. Experimental results show the new algorithm yields a higher improvement in the segmental SNR, lower residual noise and better enhancement of speech quality.
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Computer Engineering. 2011, 37(3): 180-182. https://doi.org/10.3969/j.issn.1000-3428.2011.03.064This paper proposes a face super-resolution algorithm based on Independent Components Analysis(ICA). It obtains ICs from offline training high-resolution face images by ICA. The prior of ICA coefficients are estimated by performing PCA on training images. For a low-resolution image, the high-resolution image is reconstructed by the linear combination of the ICs where the weight coefficients are obtained by Maximum A Posteriori probability(MAP). A structure-tensor-based filter is proposed to refine the estimated image. Experimental results demonstrate that the algorithm is robust to various pose, expressions and lighting conditions. And the hallucination results preserve both the global structure and the high spatial-frequency information better such as sharp edges and high contrast. After that, reconstruction results are used for face recognition which improves the recognition rate.
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Computer Engineering. 2011, 37(3): 183-185. https://doi.org/10.3969/j.issn.1000-3428.2011.03.065Different from the widely used automatic abstraction algorithm based on statistical learning method, this paper proposes an automatic abstraction algorithm based on Explicit Semantic Analysis(ESA) to analyze the meaning of words and document fragments in a concept space built with knowledge-intensive resources such as Wikipedia. Experimental result shows that, compared with traditional algorithm, it reaches better accuracy and higher information coverage rate while with less sentences.
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Computer Engineering. 2011, 37(3): 186-188. https://doi.org/10.3969/j.issn.1000-3428.2011.03.066A new kind of algorithm which can get the minimum Bounding Boxes(BB) based on the pixel tracing method is presented, and the music score symbols in Pipa Gong-Che notation image can be cut and extracted. By means of counterclockwise rotation extension scanning, the smallest external rectangle can be labeled surrounding each pixel connected region which is the component of the music sore symbols. And then the BB which belong to the same symbols are merged depending on the position of each other. Single music score symbol is extracted. Results of experiments indicate the algorithm can cut and extract each music score symbol correctly.
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Computer Engineering. 2011, 37(3): 189-191,194. https://doi.org/10.3969/j.issn.1000-3428.2011.03.067The theoretical study and experimental demonstration of Support Vector Regression(SVR) based on Radial Basis Function(RBF) shows that the selection of penalty coefficient, the width of insensitive loss function and kernel function parameter can affect the accuracy of non-linear function approximation. It provides an experience range of SVR parameters to select parameters in non-linear approximation, which reduces the blindness of artificial selection parameters and narrows the search range of parameters optimization algorithm to reduce algorithm whole time complexity and space complexity.
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Computer Engineering. 2011, 37(3): 192-194. https://doi.org/10.3969/j.issn.1000-3428.2011.03.068This paper proposes a gait recognition algorithm based on Fuzzy Principal Component Analysis(FPCA) for gait energy image. It preprocesses the original gait sequence to obtain Gait Energy Image(GEI), extracts the eigenvalues and eigenvectors by FPCA which are called fuzzy components, projects the eigenvectors into lower dimension space, and utilizes the NN classifier in feature classification. The algorithm is tested on CASIA database, and experimental results show that compared with other algorithms, its recognition performance is better.
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Computer Engineering. 2011, 37(3): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2011.03.069Semantic Web service discovery based on Quality of Service(QoS) exists immature convergence and Pareto set uneven distribution. Aiming at this problem that this paper gives a semantic Web service discovery based on hybrid Particle Swarm Optimization(PSO) algorithm based on introduces threshold-based particle compare standards, crowded distance functions and backface mutation operator. Experimental results show that this method has higher matching degree and precision.
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Computer Engineering. 2011, 37(3): 198-200. https://doi.org/10.3969/j.issn.1000-3428.2011.03.070This paper defines the approximation of rough set theory, introduces pheromone exchange mechanism and exchange rate. It improves traditional Ant Colony Algorithm(ACA) by self-adapting each group of ants between pheromone strength, applies to the rough set attribute reduction algorithm. Experimental results show that the algorithm can improve minimum attribute reduction of possibilities, and it has good convergence speed and local optimal solution compared to other attribute reduction algorithms.
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Computer Engineering. 2011, 37(3): 201-203. https://doi.org/10.3969/j.issn.1000-3428.2011.03.071This paper presents an image segmentation method based on neighborhood features and clustering. In the method, five dimensional neighborhood features of pixels are extracted, incremental clustering is used in order to make similar elements have a high similarity and different elements have a vary greatly different similarity, pixels in the image are classified division to achieve the correct segmentation of target image. Experimental results demonstrate that this method can accurately locate image edge, it has a strong anti-noise property and higher accuracy of segmentation.
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Computer Engineering. 2011, 37(3): 204-206. https://doi.org/10.3969/j.issn.1000-3428.2011.03.072Aiming at spectrum aliasing problems in the directional subbands during the contourlet transform, considering the limitation of the traditional measure KL Distance(KLD) between two hidden Markov models, this paper proposes a texture image retrieval method based on improved KLD, using Non-Aliasing Contourlet Transform(NACT) Hidden Markov Tree(HMT) model. The algorithm uses NACT to decompose a texture, which can deal with the spectrum aliasing phenomenon well, trains the HMT model and takes the HMT model parameter set as the texture features. It computes the similarity between two models using improved KLD, which meets the triangle inequality properties and can measure the distance better. The proposed algorithm is verified by theory and experiment, and results show that the precision of proposed method improves 2.81 percent than that of the CT-HMT combining traditional KLD measure method.
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Computer Engineering. 2011, 37(3): 207-209. https://doi.org/10.3969/j.issn.1000-3428.2011.03.073Existing image fusion algorithms have the phenomenon of frequency-domain aliasing, and the commonality of algorithms is poor. Aiming at this problem, this paper improves an algorithm from the aspects of low-pass anti-aliasing filtering and sub-pixel mapping point of view, and makes the sub-pixel mapping formula more general. Experimental results show that the improved algorithm has certain advantages in qualitative visual effects and quantitative image quality assessment.
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Computer Engineering. 2011, 37(3): 210-212. https://doi.org/10.3969/j.issn.1000-3428.2011.03.074Aiming at the disability of traditional Canny operator in noise suppression and detecting low-intensity edge, this paper proposes an edge detection method combined LOG operator and Canny operator. LOG operator is used to the picture for noise filtering and Canny operator is improved in the flowing three aspects to execute the edge detection: (1)It designs Gaussian smoothing kernel to intense the edge of picture filtered noise, which makes the low-intensity edge detect easily; (2)Gradient magnitude and direction are calculated by pixels within a M-by-N neighborhood; (3)It integrates gradient direction with the calculation of gradient magnitude, which can be the ground for gradient magnitude in edge detection. Through carrying out a lot experiment for picture increased salt and pepper noise, the method proposed in this paper can not only suppress noise in the largest degree, but also detect more low-intensity edge.
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Computer Engineering. 2011, 37(3): 213-214,217. https://doi.org/10.3969/j.issn.1000-3428.2011.03.075Aiming at the problem that the ability of details protection is not well in traditional algorithms, this paper proposes a filtering algorithm based on impulse noise detection and signal compression. During noise detection, it sorts the pixel points in detection window, and the pixel points in the field of extreme value in the vicinity whose gray value fell within a certain range are judged to be noise points. During noise filtering, it extracts signal points and compresses these points so as to further exclude false detections. It chooses different filtering method according to different noise density, and does cyclic iteration until all impulse noise points are filtered. Experimental results show that the algorithm has a better ability of filtering impulse noise and protecting details, especially under the conditions of high-intensity noise, it has more obvious effect.
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Computer Engineering. 2011, 37(3): 215-217. https://doi.org/10.3969/j.issn.1000-3428.2011.03.076This paper proposes an improved energy functional of variational model, the data terms are composed of the brightness constancy assumption and the Hessian constancy assumption, and combines with Lucas’ local constancy assumption. As for the design of smoothness term in the energy functional, it selects the method of using isotropic strategy first then using anisotropic strategy, with embedding coherence enhancing diffusion strategy. Experimental results prove that the method is improved to a certain extent compared with the previous variational model of optical flow calculation.
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Computer Engineering. 2011, 37(3): 218-221. https://doi.org/10.3969/j.issn.1000-3428.2011.03.077Aiming at some problems such as poor contrast and edge blur in remote sensing image fusion, by using the statistical learning advantages of Support Vector Machine(SVM) and combining with the multi- directional characteristics of filter bank, this paper proposes a framework for remote sensing image fusion based on SVM. Compared with other kernel functions, wavelet kernel function has better approximation ability on complex signals. So in this paper, through kernel function constructed by Morlet mother wavelet function, remote sensing images fusion based on wavelet SVM is researched. It can improve the accuracy of remote sensing image fusion. Experimental results show that the fusion effect of the method is better than traditional image fusion methods.
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Computer Engineering. 2011, 37(3): 222-223,226. https://doi.org/10.3969/j.issn.1000-3428.2011.03.078According to the feature that fractal image compression algorithm has the potential of high compression ratio, this paper presents a hybrid image compression algorithm based on fractal and JPEG. It uses fractal image compression algorithm based on quadtree algorithm for encoding and decoding of 32×32 and 16×16 sub-block area, uses JPEG algorithm for residual regional encoding and decoding. Experimental result shows that this algorithm has better compression ratio and decoded image quality, the mass effect of decoding image obviously weak in JPEG algorithm when the compression ratio is large.
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Computer Engineering. 2011, 37(3): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2011.03.079Aiming at the shortcoming of wavelet which can’t efficiently capture image contour, this paper proposes an image fusion algorithm based on the second generation curvelet transform. It proposes a fusion rule containing weighted mean approximate coefficients and details coefficients combined with extended pixel-level multiresolution fusion framework, as well as contrast sensitivity band-pass function. It employs the subjective and objective evaluation to assess fusion results. Experiments indicate that the proposed approach is superior to wavelet in preserving source image edge contour and noise suppression, and fusion images better correspond with human visual perception characteristics.
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Computer Engineering. 2011, 37(3): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2011.03.080In the background of study on activity regularity of the sun-earth system, this paper proposes an efficient multi-physics coupling interaction mechanism PRMI++ for sun-earth system based on SCIRUN group’s PRMI with four-point improvement. It can automatically accomplish gird re-mapping and parallel distribution re-mapping of data when the physical model components on the parallel remote method invocation to achieve coupling interactions. Experimental results prove PRMI++ has better performance.
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Computer Engineering. 2011, 37(3): 230-232,235. https://doi.org/10.3969/j.issn.1000-3428.2011.03.081Aiming at the safety problem of rail transit equipment, this paper designs and implements Vital Coded Pre-Compiler(VCPC) based on the coding principle of Vital Coded Processor(VCP). VCPC can transform the source codes into codes which are safe and can be verified. Faults are detected by the safe codes running on VCP’s single processor. Test results show that the non detection probability of an error can be 1/A.
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Computer Engineering. 2011, 37(3): 233-235. https://doi.org/10.3969/j.issn.1000-3428.2011.03.082Aiming at the problem of large communication rate differences between actual value and theoretical value in Universal Serial Bus(USB) development, USB communication rate is optimized in data exchange method and host side driver according to the characteristics of USB interface device PDIUSBD12 and USB protocol itself. A Direct Memory Access(DMA) controller applicable to expanded memory bus of LPC2200 series device using Flash FPGA is presented. Experimental results show that those optimization methods remarkably increase the USB data communication rate on PDIUSBD12.
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Computer Engineering. 2011, 37(3): 236-237,240. https://doi.org/10.3969/j.issn.1000-3428.2011.03.083This paper introduces the RapidIO protocol and the hardware platform of RapidIO interconnect system which is composed of MPC8641D and Tsi578 switch chip. On this platform, it designs the RapidIO drive based on VxWorks operating system, carries out the main function of RapidIO, such as read and write, message passing, doorbell transaction and so on, and tests the bandwidth and latency of RapidIO communication mechanism, validates the basic skill and performance of RapidIO communication.
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Computer Engineering. 2011, 37(3): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2011.03.084Since the performance of normal motor drive suffers from the inverter nonlinearities such as device voltage drop, dead-time effect and switch on/off time, a novel inverter nonlinearity compensation strategy based on immune clonal algorithm is proposed in this paper. Compared with the normal compensation method, the proposed method can identify the equivalent voltage caused by inverter nonlinearity and motor winding resistance without checking the dead time given by DSP, inverter turn on/off time and device voltage drop. The proposed strategy is employed in a Permanent Magnet Synchronous Machine(PMSM) drive system and its accuracy is verified through comparison between the identified results and the parameter values listed in the inverter datasheet.
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Computer Engineering. 2011, 37(3): 241-243,247. https://doi.org/10.3969/j.issn.1000-3428.2011.03.085To alleviate the burden of CPU and improve system performance, a TCP Offload Engine(TOE) system based on Field Programmable Gate Array(FPGA) is designed and implemented. This TOE network adaptor adopts a hardware solution to implement some TCP protocol software dataflow processing, such as packet classification and TCP stream reassembly. Test results show that TOE network adaptor can greatly decline host’s CPU utilization.
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Computer Engineering. 2011, 37(3): 244-247. https://doi.org/10.3969/j.issn.1000-3428.2011.03.086This paper proposes a WCET-based static allocation algorithm for Scratch-Pad Memory(SPM), the algorithm obtains the Worst-Case Execution Path(WCEP) through an external Worst-Case Execution Time(WCET) estimation tool. According to the WCETP, the algorithm transforms the application into a directed graph consisting of nodes and relationships of nodes. It applies an algorithm which takes the relationships of nodes into account to solve the problem of SPM memory allocation. Simulation experiments show that the algorithm achieves an improvement of about 54% in the real-time performance, compared to system without SPM.
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Computer Engineering. 2011, 37(3): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2011.03.087The current circumstance of Mandarin learning in Xinjiang is introduced. It is significant to develop a Computer Assisted Language Learning(CALL) system oriented to the mandarin learning of Xinjiang. Then it proposes the unsolved problems and system objectives. The focus is the principle and procedure of speech evaluation as well as dynamic translation. A multilingual mandarin assisted learning system is developed with the pivotal technologies. Although the system is still not perfect, it can assist the learning of mandarin effectively. The system can make contributions to the bilingual education and mandarin popularization of Xinjiang. It is worth being popularized.
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Computer Engineering. 2011, 37(3): 251-253,256. https://doi.org/10.3969/j.issn.1000-3428.2011.03.088To solve the problem that the existing consistency checking algorithm of STN can only detect temporal conflicts but can’t resolve them, this paper proposes an iterative algorithm of conflict detection and resolution based on negative cycle detection algorithm. A conflict resolution method based on the cost of modifying constraints is designed, and the negative cycle detection algorithm work is made incrementally. It improves reasonability and speed of conflict resolution, reduces the burdens of planners. Experimental results prove the efficiency of this algorithm.
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Computer Engineering. 2011, 37(3): 254-256. https://doi.org/10.3969/j.issn.1000-3428.2011.03.089In the process of solution optimization, in order to eliminate effect of random factors, Monte Carlo simulation is needed. This paper describes how to introduce confidence interval into system-of-systems combat simulation, so whether to end the Monte Carlo simulation based on data generated from simulation process can be determined. And based on the character of data, the confidence interval method is extended, so the number of experiments at the condition of meeting the precision requirement of solutions can be minimized. Simulation results show that the extended confidence interval method can control Monte Carlo simulation adaptively.
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Computer Engineering. 2011, 37(3): 257-259. https://doi.org/10.3969/j.issn.1000-3428.2011.03.090There are two shortcomings on the research of Order Fulfillment System(OFS): first, order promising and demand fulfillment, divided by OFP, are seldom integrated for research under the same system; second, little research focused on the architecture of OFS, although it need too much information in other systems. To solve the above problems, with a core of integrated OFP based on Theory of Constraints(TOC) and support of Web service technique based on Service Oriented Architecture(SOA), an integrated OFS is designed and implemented. The successful application for the system in one large enterprise validates the feasibility of the Process and the architecture.
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Computer Engineering. 2011, 37(3): 260-262,265. https://doi.org/10.3969/j.issn.1000-3428.2011.03.091The FCM provides a glueless interface to parallel-bus NAND Flash E2PROM devices within MPC837x microprocessors. This paper analyses the transmission mechanism of FCM mode and the drive architectures of TrueFFS in VxWorks based on VxWorks and MPC8379E embedded system developing platform, introduces the drive design of NAND Flash under FCM interface and provides the method to realize TrueFFS drive interface. FCM interface drive can be easily embedded in other embedded systems based on hierarchical drive design.
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Computer Engineering. 2011, 37(3): 263-265. https://doi.org/10.3969/j.issn.1000-3428.2011.03.092In order to reduce hardware overhead, this paper proposes a method where the adders, subtracters and multipliers inside of a data path are used to generate test vectors. Experimental results show that the proposed Design For Testability(DFT) and test scheduling approach has good performance and practicality. Under a given power constraint, the hardware overhead can be reduced from 10.7% to 73.4%. The test application time can also be reduced up to 22.4%.
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Computer Engineering. 2011, 37(3): 266-268. https://doi.org/10.3969/j.issn.1000-3428.2011.03.093Aiming at the problem that it is hard to synthesize handwritten Chinese character, this paper proposes a new method of handwritten Chinese character synthesis based on the structure knowledge of off-line Chinese character. It uses improved direction distance length algorithm to extract stokes of character and establishes stoke bounding boxes, synthesizes handwritten Chinese character based on the knowledge of stoke bounding boxes. Experimental result shows that the method is effective for generating some Chinese characters, these characters are easy to be recognized by human and their resistances to OCR(Optical Character Recognition) are strong.
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Computer Engineering. 2011, 37(3): 269-271,274. https://doi.org/10.3969/j.issn.1000-3428.2011.03.094The navigation performance of hybridized navigation system determines whether the aircraft can fly on the route of certain navigation specification when under Performance Based Navigation(PBN) operation, which is the key technology of PBN implementation. Taking DME/DME/IRS hybridization as an example, the assessment method of onboard navigation system is given out, Kalman filter and Gaussian density are used to determine the navigation performance, and simulation is done for this method. Simulation results indicate this method is good for real-time calculation, it can calculate the navigation accuracy under different integrity requirement and is useful, and the calculation is simple.
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Computer Engineering. 2011, 37(3): 272-274. https://doi.org/10.3969/j.issn.1000-3428.2011.03.095According to the modern high-technology war conditions, a positioning system of self-propelled artillery is proposed based on ZigBee,. In order to realize real-time field artillery location estimation, this paper constructs the artillery location wireless network system based on ZigBee. It researches conditions of artillery formation boundary, so that the network can be realized. Using C/S network that can be substituted makes sure the unitarity of operation order. The system can be used for a battalion or company and it can enhance the combat effectiveness of the units.
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Computer Engineering. 2011, 37(3): 275-277. https://doi.org/10.3969/j.issn.1000-3428.2011.03.096Because of various application fields, hardware design and Bootloader of embedded system, the function of soft-shutdown is not supported by Windows CE when it is published. With increasingly extensive application of embedded system, the problem of safely saving data and soft-shutdown becomes more and more important. This paper proposes a kind of soft-shutdown method combining software and hardware based on MCU, and introduces key technologies to realize. Safe shutdown can be realized by the method on various conditions with power down detection and protection circuits. The method has good generality and expansibility.
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Computer Engineering. 2011, 37(3): 278-280,283. https://doi.org/10.3969/j.issn.1000-3428.2011.03.097Confronting the deficiencies in real-time, concurrency and integrity and so on for sending short message with Modem, the real-time and concurrent algorithm for short message based on multi-Agent and Multi-Priority Queue(Multi-PQ) is introduced. Technological measures such as multi-Agent, Multi-PQ and thread pool are adopted to control the message for real-time, concurrency and integrity. And the PQ is used in algorithm to send some message. The algorithm is verified by improving queuing theory and experiments. It is used in SMAS system, result shows that the speed and efficiency is quickly increased after using the algorithm. The aim for real-time and concurrency is achieved, and the performance of the SMAS system is improved.
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Computer Engineering. 2011, 37(3): 281-283. https://doi.org/10.3969/j.issn.1000-3428.2011.03.098A new Frame Rate Up-Conversion(FRUC) approach based on triangulation mesh is proposed. The algorithm constructs a triangular mesh based on the identified nodes of the current frame, which is extracted by implementing the redundant wavelet transform. It gets the motion vectors of the identified nodes by estimating displacement of such nodes from the previous frame with respect to the current frame in the triangular mesh. The new frame is rendered based on the reference frames and the estimated displacement of nodes. Experimental results show that the proposed algorithm provides better performance than conventional motion-compensated interpolation approach.
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Computer Engineering. 2011, 37(3): 284-286,289. https://doi.org/10.3969/j.issn.1000-3428.2011.03.099In the context of water grid, this paper studies the mechanism of the water grid task registration, proposes the concept of parameter-driven, and combines the workflow technology with the water grid task registration. It presents the visualization way of the water grid task registration based on workflow, and introduces the process of the designation of the task registration component. This paper takes the heavy rain on the Weihe river as the assumption, draws the “task map of Xi’an economic loss caused by heavy rain on the Weihe River”. It also proposes the request of the combination between tasks.
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Computer Engineering. 2011, 37(3): 287-289. https://doi.org/10.3969/j.issn.1000-3428.2011.03.100In order to protect users’ privacy in UHMS, this paper proposes a privacy preserving model for authentication, ubiquitous home medical system authentication privacy preserving model——uPPM. The proposed model uses Platform for Privacy Preference(P3P) standard technology, improves Role-Based Access Control(RBAC) policy and credible third-party organization. There are three basic entities in model, including users, privacy control center and home medical center. The model combines with information hiding technology, privacy preferences strategies and agent technology organically to adapt to the characteristics of pervasive computing——context-aware. It is analyzed and proved to be correct and safe by the model based on BAN logic.
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Computer Engineering. 2011, 37(3): 290-292. https://doi.org/10.3969/j.issn.1000-3428.2011.03.101Due to the poor performance of traditional Minimum Mean Square Error Short-Time Spectral Amplitude estimator(MMSE-STSA) algorithm in non-stationary noise environment, this paper proposes an improved MMSE-STSA speech enhancement algorithm, which is based on a loudness-domain MMSE estimator in the frequency domain, and uses a probability-based voice decision method. Simulation result indicates that it has better performance than traditional MMSE-STSA algorithm in non-stationary noise environment.
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