05 August 2011, Volume 37 Issue 15
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Computer Engineering. 2011, 37(15): 1-5. https://doi.org/10.3969/j.issn.1000-3428.2011.15.001
In order to construct the Magnetic Resonance Imaging(MRI) database from online literature, MRI image recognition and brain MRI recognition are studied. In this paper, two complementary features, Pyramid Histogram of Orientated Gradients(PHOG) and Pyramid Histogram of Words(PHOW) are adopted to extract and describe the features of images. An improved Support Vector Machine(SVM) classifier based on feature fusion which combines spatial shape and local distribution information is proposed. Experimental result shows a significant improvement in the average accuracy of the fusion classifier as compared with classifiers only based on PHOG or PHOW. It provides a foundation of building a knowledge base system that can interpret MRI images in online articles.
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Computer Engineering. 2011, 37(15): 6-9. https://doi.org/10.3969/j.issn.1000-3428.2011.15.002
It is difficult for model-unknown non-hyperbolic non-linear sequence to realize denoising or shadowing of non-linear time sequences. Aiming at the problem, based on the minimal description length criteria, this paper points out that the marginal error algorithm is not optimal to the discrete system, sometimes even inadaptable from the viewpoint of over-fitting and under-fitting. A modified algorithm named total error algorithm is proposed and analyzed. And a highly-stable-but-fast hybrid algorithm is developed which compensates both the slower convergence of gradient decent algorithm and the worse stability of Newton-Raphson algorithm. The machine precision is obtained for the noisy time sequences of model- unknown non-linear discrete system. Experimental results prove that the method is efficient to solve the denoising or shadowing problem of non-linear time sequences.
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Computer Engineering. 2011, 37(15): 10-13. https://doi.org/10.3969/j.issn.1000-3428.2011.15.003
In liquid and smoke simulation using Euler model, the common Semi-Lagrangian Method(SLM) has numerical viscosity due to excessive averaging steps, and the surface extracting method will further smear out details of water surface. This paper proposes a stable and detail-preserving liquid and smoke simulation algorithm. It employs numerical method with higher numerical accuracy to solve advection term. The algorithm distributes massless implicit particles near the surface and in the fluid volume, using simple interpolating strategy and utilizing the bidirectional influence between particles and grid, achieving the target of guaranteeing numerical stability and reducing numerical viscosity. It combines with surface tracking method based on explicit surface to achieve rich visual effects. Experimental results demonstrate the algorithm has the capability of preserving details.
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Computer Engineering. 2011, 37(15): 14-16,22. https://doi.org/10.3969/j.issn.1000-3428.2011.15.004
In order to solve the problem, i.e. finding out the signals and modules that are more vulnerable to environmental disturbance and should be assigned errors detecting and correcting mechanisms or fault tolerance techniques, this paper designs a method to analyze error propagation rules and an implement algorithm is put forward. Some reliability indices are introduced such as error propagating rate and error exposure rate. The error detecting and correcting mechanisms can be deployed on those more vulnerable signals and modules. Through a fault injection experiment, all indices are computed. At the same time, the experiment process proves the effectiveness and validity of algorithm.
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Computer Engineering. 2011, 37(15): 17-22. https://doi.org/10.3969/j.issn.1000-3428.2011.15.005
This paper introduces an Edge-independent Time Evolving Graph(E-TEG) model to capture the evolution of the connectivity properties of Opportunistic Networks(OppNet). E-TEG model is presented through using discrete time Markovian model to deal with the time dependencies of consecutive time-step indexed network snapshots, and the dynamic of each possible edge is assumed to be an independent birth-death process. In addition, given the sequence data, the birth and the death probability of each edge are estimated through using Laplace’s rule of succession. It shows that an E-TEG eventually converges to an un-uniform random graph. E-TEG model is validated through CRAWDAD trace datasets by computing the fastest path of each pair of nodes in an instance of E-TEG.
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Computer Engineering. 2011, 37(15): 23-26. https://doi.org/10.3969/j.issn.1000-3428.2011.15.006
In order to detect boundary points of clustering automatically and effectively, and to eliminate the impact of parameters on the results of the boundary detection, a new nonparametric boundary detection algorithm based on delaunay triangulation is presented. This algorithm calculates the boundary degree for each point in the generated delaunay triangulation without any parameters. According to the boundary degree’s threshold that is automatically calculated by k-means, dataset is divided into two parts: candidate set of boundary points and the set of non-boundary points. Based on the characteristics of the noise points, the noise points are removed from the candidate set of boundary points. It detects out boundary points of clustering. Experimental results show that the algorithm can identify boundary points in noisy datasets containing clustering of different shapes and sizes effectively and efficiently.
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Computer Engineering. 2011, 37(15): 27-29,33. https://doi.org/10.3969/j.issn.1000-3428.2011.15.007In order to achieve workflow system for the control of workflow evolution and to solve the problem of dynamic adjustment of the workflow model, this paper presents formal specification and correctness criteria of workflow model briefly. Based on the execution history of process instance, an efficient virtual execution algorithm involving flow change is proposed, which is also applied to loop structure. The algorithm can determine whether an instance can be smoothly migrated, through the means of rollback and aborting, it guarantees that the work done is valid at maximum and workflow instances are migrated rapidly and automatically. A case is introduced to validate the correctness and applicability of the algorithm.
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Computer Engineering. 2011, 37(15): 30-33. https://doi.org/10.3969/j.issn.1000-3428.2011.15.008Increasing number of software versions and the limitation of test resources challenge the traditional methods of regression test. This paper presents a new approach to select test subset for regression test by building the decision tree of test knowledge system. Test cases and test requirements are denoted as a test knowledge system in this method. The test knowledge system is reduced by eliminating redundant attributes. It builds the decision tree from the reduced test knowledge system. A test subset can be obtained from the decision tree. To implement the method by computer, it also gives the algorithm for reducing test knowledge system and the algorithm for building the decision tree.
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Computer Engineering. 2011, 37(15): 34-36. https://doi.org/10.3969/j.issn.1000-3428.2011.15.009Aiming at some problems of present XML queryable compressors, this paper proposes the definition and detailed algorithm of structure sign tree, which can simplify the structure of XML data by removing the repeated paths. On the basis, a new XML queryable compressor SSTQC is put forward to compress XML data and organize queries. SSTQC requires only a single pass over the XML document, and it has excellent compression performance and better query efficiency.
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Computer Engineering. 2011, 37(15): 37-39,54. https://doi.org/10.3969/j.issn.1000-3428.2011.15.010Aiming at the lack of similar sub-patterns discovery algorithm from time series based on points distance such as poor robustness, an algorithm is proposed for similarity measure and approximate representation of time series based on morphological character. Fully used the time-varying characteristics, time series are divided by angular points, and its characters are extracted with bending degrees at angular points to approximate the time series. The algorithm does not depend on the length of time series and domain knowledge. Experimental results show that this algorithm is not only invariant to translation and scalability, but has good robustness, and the results are more effective.
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Computer Engineering. 2011, 37(15): 40-42,45. https://doi.org/10.3969/j.issn.1000-3428.2011.15.011For the choice of initial cluster K-Means clustering algorithm is very sensitive, its results are frequently a local optimal solution rather than a global optimal solution. On the premise of studying K-Means clustering algorithm, this paper introduces a concept of clustering and competitive learning, and proposes a combination clustering algorithm of K-Centroid based on competitive learning(CLK-Centroid algorithm). CLK-Centroid algorithm adapts the noise data and outliers by using a strategy of competitive learning to compute a cluster Centroid, and improves the precision of cluster by using a strategy of combination clustering. Building a multiple of CLK-Centroid clustering models to cluster on data set, the different sub-cluster that comes from the different clustering results must contain an intersection. The sub-cluster similarity matrix is built to merge similar cluster according to the similarity between the sub-clusters. Theoretical analysis and experimental results show that the algorithm can improve the clustering quality.
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Computer Engineering. 2011, 37(15): 43-45. https://doi.org/10.3969/j.issn.1000-3428.2011.15.012Based on research of Pellet concept of ontology classification algorithm and some optimization techniques, this paper presents a method based on extend tag improvement. The method is mainly through the use of the inclusion relations concept between the known, taking control of the classification process of inclusion of the traversal order, and the maximum two-way dissemination of these relationships, thus effectively reducing the number of concept subsumption test. Algorithm verification results show that the refined algorithm improves the performance on average by about 22% when carrying out the concept classification.
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Computer Engineering. 2011, 37(15): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2011.15.013In order to solve the intelligent transportation system in transportation network analysis and the shortest path problem, this paper proposes a weighted identification S-graph shortest path algorithm. According to the basic principle and Petri nets weighted S-graph characteristics, it puts forward the weighted S-graph network model. A weighted identification shortest path S-graph basic principle is illustrated, a weighted S-map identifies the shortest path. Through the transportation network of sample and experiment verified, the algorithm is compared and analyzed. Experimental results show that the weighted identification S-graph shortest path algorithm for solving the transport network is an effective method for the shortest path.
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Computer Engineering. 2011, 37(15): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2011.15.014The current research progresses and the existing problems of Unified Modeling Language(UML) class diagram formalization methods based on description logics are analyzed. A kind of formalization method of UML class diagram with dependence attributes based on description logics is presented. It proceeds studying the formalization problems of data attributes dependence, action attributes dependence and global attributes dependence of UML class diagram with dependence attributes based on description logics. The method of how to translate UML class diagram with dependence attributes into knowledge bases is given, as well as the satisfiability theorem of UML class diagram with dependence attributes knowledge bases, and the correctness of the theorem is proved.
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Computer Engineering. 2011, 37(15): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2011.15.015A Java Virtual Machine(JVM) garbage collection algorithm in real-time environment is presented. The proposed algorithm improves the heap space division and reference tracking in incremental collector for reducing the uncertain pause caused by garbage collection. Furthermore, this algorithm allows users to assign a specified period in the garbage collection in order to obtain the shortest pause time. All of these make the proposed algorithm suitable for real-time environment. Experiment results show that this algorithm can effectively reduce the frequency and duration of pauses.
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Computer Engineering. 2011, 37(15): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2011.15.016In order to meet file system level performance evaluation needs of massive storage system, a general file system benchmark conforming to POSIX.1 is developed. It provides an effective method to evaluate different file systems. It also offers reliable data to the developers who use POSIX.1 file system API to design applications. With the cluster test structure, LZpack can make precise evaluations of file I/O performance and file system metadata operation performance. This paper not only makes clear descriptions of the system structure and key features of LZpack, but also analyzes the results from tests in different file systems under the application of LZpack. It puts forward the train of thought on improvement of LZpack in later stage.
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Computer Engineering. 2011, 37(15): 58-59,62. https://doi.org/10.3969/j.issn.1000-3428.2011.15.017Aiming at the problem of the big system cost of the call delivery process in the 3G network, this paper proposes an improved call setup mechanism, which takes the local routing and caching. The present call setup mechanism is optimized. Simulation results show that there is an optimal threshold to balance location update and terminal paging cost to obtain the minimum total cost of location management, and the optimized mechanism can reduce the system cost of the call delivery process effectively.
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Computer Engineering. 2011, 37(15): 60-62. https://doi.org/10.3969/j.issn.1000-3428.2011.15.018Under throughput requirements, the impact of selfish power control behaviors on the network performance is studied. Employing the modulation scheme Non-coherent Frequency Shift Keying(NFSK), the existence of the optimal transmission strategy is proved, and a repeated dynamic game is proposed. Since links are motivated to move the transmission power from high interference durations to low interference ones, this game can not converge in some cases. A penalty function is introduced to ensure convergence, which is verified by simulation.
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Computer Engineering. 2011, 37(15): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2011.15.019A composite efficiency index for damage condition evaluating with characteristic of two dimensions is constructed for the purpose of measuring network performance affected by network structure damage and dynamic flow change, nodes removal methods based on degree and interface numerical are used to simulate the intensive attack towards the networks, the reciprocal of total flowing cost is treated as the composite efficiency indicator for destructiveness evaluating and the evaluation algorithm is also designed. The node invulnerability evaluation index is illustrated by a case of express enterprise’s distribution network in the end, results shows that this index can effectively reveal the damage condition of most real networks with dynamic flow.
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Computer Engineering. 2011, 37(15): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2011.15.020A novel power control Medium Access Control(MAC) protocol for multi-hop dense Mobile Ad hoc Networks(MANETs) is proposed to realize high energy efficiency and improve network throughput. The basic idea of the proposed protocol is that, using the more flexible contention window adjustment method to resolve collisions efficiently. Simulation results show that the proposed protocol is efficient and can improve network throughput in most scenarios.
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Computer Engineering. 2011, 37(15): 69-72. https://doi.org/10.3969/j.issn.1000-3428.2011.15.021Resources optimization of cross-layer is a very important part in cognitive wireless networks design, and it is a typical multi-objective optimization problem. This paper proposes an adaptive clone and neighbor selection algorithm to resolve the problem of optimization resources allocation in cognitive wireless networks, and uses the algorithm to optimize three goals of used bandwidth, power consumption and rate of data transmission in cognitive networks. Simulations and comparisons in two typical test functions show that the proposed algorithm can effectively solve the problem of multi-objective optimization, such as spectrum resources allocation, power control and rate improvement, it is more superior than SPEA-2 algorithm and NNIA algorithm.
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Computer Engineering. 2011, 37(15): 73-75. https://doi.org/10.3969/j.issn.1000-3428.2011.15.022This paper proposes a new high efficient algorithm based on Vertical Bell Laboratories Layered Space-Time coding(V-BLAST) for MIMO-OFDM systems. The proposed QMC algorithm sorts the channel matrix, and uses the QR decomposition. At the beginning of the detection, the Maximum Likelihood-Ordered Serial Interference Cancellation(ML-OSIC) algorithm is utilized, and the M algorithm is applied to detect the middle symbol layers with M gradually increasing for more efficiency, then the SIC is used for detecting the remained symbol layers. Compared with the conventional QRD-M algorithm, the proposed algorithm significantly reduces the complexity and its performance gets closer to Maximum Likelihood Detection(MLD) performance. Simulation results show that the performance of the proposed QMC algorithm is very close to the MLD algorithm, it obtains a better tradeoff between complexity and performance.
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Computer Engineering. 2011, 37(15): 76-78. https://doi.org/10.3969/j.issn.1000-3428.2011.15.023Current network message transmission is based on store and forward mechanism. The network node does not process any messages. Network coding theory allows nodes coding and transmitting messages. This paper uses character of network coding package carrying more information to design reciprocal P2P network resource sharing method, which achieves reliability and robustness of P2P resource sharing. Through simulation experiment to evaluate the performance of P2P resource sharing system. Simulation experimental results show that network coding reciprocal resource sharing method makes P2P resource sharing application scalable and efficient.
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Computer Engineering. 2011, 37(15): 79-81. https://doi.org/10.3969/j.issn.1000-3428.2011.15.024In order to improve the Transmission Control Protocol(TCP) performance over wireless networks, the possible reasons of data loss for Ad Hoc network is discussed and the efficient of loss differentiation scheme is proposed. It designs the scheme of detection based on one-way trip time of duplicate Ack. According to the scheme, the sender can adopt immediately the appropriate congestion control. Simulation results show that the proposed scheme can improve the TCP performance efficiently.
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Computer Engineering. 2011, 37(15): 82-84,88. https://doi.org/10.3969/j.issn.1000-3428.2011.15.025This paper presents a basic hierarchical-based communication system modeling method combining the concept of object-oriented and making use of Colored Petri Net(CPN), which can solve the existing problems of high complexity, poor reliability, lack of formal verification methods, and low reusability in communication system modeling. This method reflects the advantages of CPN and object-oriented technology, and describes the operation process of basic communication system from the formal and visual aspects. Taking a simple basic communication system as example, it gives the specific description on each layer of CPN. The model is correspondent with the object of the actual system, which is easy to understand and realize.
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Computer Engineering. 2011, 37(15): 85-88. https://doi.org/10.3969/j.issn.1000-3428.2011.15.026During the process of carrying out K coverage algorithm of Wireless Sensor Network(WSN) to the target area, there are some shortcomings, such as many redundancy nodes emerge, the process consumes a lot of node energy in the network at the same time, and the process is easily restricted by the outside environmental elements. This paper puts forward an event probability K coverage algorithm. By means of giving different probability value to different monitor degree of the target area nodes, and by way of information exchange and relevance nature between the nodes, the algorithm fixes the smallest nodes collection and the biggest target collection, thus effectively fulfills K coverage to target area nodes, optimizes network resources, reduces energy consumption of the nodes, and prolongs the life time of the network. Emulation experiments show that, this algorithm can fulfill K coverage to target area at small cost and increases the whole network lifetime. It has good practical result and stability.
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Computer Engineering. 2011, 37(15): 89-91,102. https://doi.org/10.3969/j.issn.1000-3428.2011.15.027The free-riding problem in Peer-to-Peer(P2P) network makes nodes only use information resources instead of contributing resources for the system. It leads resources continue to decrease, which seriously affects the P2P network system performance. To solve the problem, this paper proposes a P2P incentive mechanism based on RDEC algorithm by using the Nash equilibrium theory. Simulation experiments and the analysis of its data demonstrate the strategy can improve resource sharing fairly and maximize the system utility.
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Computer Engineering. 2011, 37(15): 92-94,109. https://doi.org/10.3969/j.issn.1000-3428.2011.15.028Based on the grid multi-scroll Chua’s chaotic attractors and Discrete Cosine Transform(DCT) algorithm, a novel digital image watermark algorithm is proposed in this paper. It improves digital watermark algorithm using the grid multi-scroll Chua’s chaotic sequences generated by chaotic systems as the key, which greatly enhanced the security of the algorithm. The complex dynamic behavior makes up the existence of defects in the key space is too small. Experiment results show that the scheme has excellent characteristics of resistance to geometric attacks, shear, and brute-force attacks against the key space and has good features.
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Computer Engineering. 2011, 37(15): 95-97,105. https://doi.org/10.3969/j.issn.1000-3428.2011.15.029A signcryption scheme can realize signature and encryption simultaneously, and its cost is smaller than the sum of signature and encryption. However, most signcryption schemes do not have strict security proof. This paper proposes a signcryption scheme based on difficult problems of elliptic curve group. The scheme is efficient and only needs one pair operation. It proves that the scheme is semantic secure and unforgeable in the standard model. Moreover, the scheme has non-repudiation, forward security and public verification.
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Computer Engineering. 2011, 37(15): 98-99,115. https://doi.org/10.3969/j.issn.1000-3428.2011.15.030Digital watermark technique is proposed as a solution for problems of copyright projection. Most of current image watermark schemes embed watermark into host image twice. In these schemes, the values of fusion parameter effects on the visual of exacted watermark information. This paper presents a new method to compute fusion parameter adaptively which can get different result based on different host images, watermark information. It is one important aspect way that it can avoid repeat experiment and estimate of the kind of attack. Experimental results show that the proposed way yield good visual effects.
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Computer Engineering. 2011, 37(15): 100-102. https://doi.org/10.3969/j.issn.1000-3428.2011.15.031An identity-based generalized signcryption algorithm, which can fulfill signcryption, encryption and signature by one cryptographic module, is proposed to serve the broader applications. It gives an elaborate define and made an analysis of its validity and performance. The analysis shows that the algorithm achieves authenticity and confidentiality synchronously, and it has evident advantage compared to L-K scheme without considering pre-computation.
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Computer Engineering. 2011, 37(15): 103-105. https://doi.org/10.3969/j.issn.1000-3428.2011.15.032For the basic concept and important properties and difficult problems in the braid group, based on which, the designated verifier proxy signature scheme is proposed using conjugate search problem and the p-th root finding problem based on the braid group. In the designated validation period the verifier’s private key is used, in addition to the designated verifier, other people cannot verify legality of the signature. Its security is analyzed and the result shows this scheme is secure and effective, and meets the nature of the designated verifier proxy signature.
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Computer Engineering. 2011, 37(15): 106-109. https://doi.org/10.3969/j.issn.1000-3428.2011.15.033As the viruses and trojan horses are in flood, the security of smart card terminals can not always be guaranteed. Some risks may still exist in life cycle of the private key file such as generation, replacement and revocation process, resulting in various types of problems in the Public Key Infrastructure(PKI) applications based on private-key as a core. This paper elaborates the original security system of smart card, then conducts the research to the private key’s use process in the entire smart card life cycle, carries on comprehensive and the thorough analysis to the latent risk, and proposes a smart card private key protection solution based on the production public key certificate.
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Computer Engineering. 2011, 37(15): 110-112. https://doi.org/10.3969/j.issn.1000-3428.2011.15.034To improve the safety of the software, this paper proposes a software design and development method which based on Model Driven Architecture(MDA) and United Modeling Language(UML) extension mechanism. It adopts UML extension mechanism to build system safety-related Platform Independent Model(PIM), and brings forward the safety analysis of software at the early stage of design. It realizes software security property modeling with the method of MDA, and reduces risk and cost of later development period. Example of library management system proves the validity of the method.
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Computer Engineering. 2011, 37(15): 113-115. https://doi.org/10.3969/j.issn.1000-3428.2011.15.035IPSec protocol in Virtual Private Network(VPN) can’t validate the user’s identification by its weak identity authentication. This paper introduces the Public Key Infrastructure(PKI) technology into VPN, describes the application of PKI in VPN, including identity authentication, key management, access control. It gives the configuration model and function model of PKI, and analyzes the implementation of VPN user’s digital signature.
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Computer Engineering. 2011, 37(15): 116-118,121. https://doi.org/10.3969/j.issn.1000-3428.2011.15.036This paper aims to explore the security of the Virtual Machine Monitor(VMM), combined with open source virtualization software Xen to analyze the potential threats and vulnerabilities, such as tampering with hypercalls, malicious direct memory access. It designs and implements a way to undermine the stability of virtual machine by modifying VCPU state and meanwhile give countermeasures, such as verifying critical data structures to discover whether it is invaded, or forbidding the loading of module to eliminate all possible security risks posed by the module.
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Computer Engineering. 2011, 37(15): 119-121. https://doi.org/10.3969/j.issn.1000-3428.2011.15.037This paper proposes a node reputation management mechanism of secure structured P2P networks. It uses global storage to save reputation information. File reputation and peer reputation together are used for preventing untrustworthy files from spreading even in case of allowing malicious peers to change their identities. The basic operations in file sharing systems are analyzed. Simulation experiments under various kinds of node behaviour proves the validity of the secure reputation mechanisms.
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Computer Engineering. 2011, 37(15): 122-124. https://doi.org/10.3969/j.issn.1000-3428.2011.15.038Referring to unbalanced dataset, the traditional machine learning methods will achieve biased performance. Using traditional methods, the recognition rate of minority class will be lower than the recognition rate of majority class. In this paper, based on rotation forest, it proposes an improved unbalanced dataset learning method, which is called deflection forest. It reduces data unbalance by over-sampling the data of minority class. It uses random resampling to increase diversity of samples which generate the deflection matrix and then improves the accuracy rate. Experimental results show that the deflection forest method achieves better performance, which carries out higher recognition rate of minority class and also lower recognition error rate of majority class.
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Computer Engineering. 2011, 37(15): 125-127. https://doi.org/10.3969/j.issn.1000-3428.2011.15.039Aiming at the difference and antinomy of the weighting in the rough set, the relative entropy of two probability distributions is extended to the relative entropy of two one-dimension vectors. The relative entropy is viewed as a distance measurement. The values range of optimal weights are determined by determinations of attribute importance in algebra view and knowledge granularity view respectively, and a single objective optimization model is established on the grounds that attribute values of alternatives are far away from negative ideal values and as close as to ideal values. On the other hand, since the limitation of equivalence relations, dominance relations are introduced to the method of determining the attribute weights. The weights in algebra view and knowledge granularity view are carried on the organic integration by the relative entropy optimization model based on dominance relations, in order to obtain optimal solution of the attributes in Multiple Attribute Decision Making(MADM). The analysis result indicates the validity and efficiency of the model.
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Computer Engineering. 2011, 37(15): 128-130. https://doi.org/10.3969/j.issn.1000-3428.2011.15.040The Particle Swarm Optimization(PSO) algorithm has a few disadvantages in solving complex functions, including slow convergence rates, low solving precisions and high possibilities of being trapped in local optimum. An Adaptive Chaos Particle Swarm Optimization algorithm (ACPSO) is presented based on several improvements in original PSO. ACPSO improves the performances of the standard PSO by applying chaos searching mechanism to avoid premature convergence. The dynamically decreasing inertia weight is employed to enhance the balance of global and local search of algorithm. Experimental results show that the proposed algorithm not only has great advantages of convergence property over standard PSO, but also avoids effectively being trapped in local optimum.
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Computer Engineering. 2011, 37(15): 131-133,148. https://doi.org/10.3969/j.issn.1000-3428.2011.15.0041This paper proposes a primary and secondary template method to construct the conceptual relation of fairy tale. To the primary template, it introduces a partial syntactic analysis model. To the secondary template, it introduces the bioinformatics sequence alignment method. At the same time in the iteration process, it introduces the template confidence evaluation mechanisms. It extracts the concept pair of the fairy tale, experimental results show that the primary and secondary template method has high precision rate.
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Computer Engineering. 2011, 37(15): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2011.15.042Traditional information retrieval model has the problem of low accuracy when obtaining the information. In order to solve the problem, this paper proposes a new information retrieval model based on field theory by analyzing the shortcomings of traditional information retrieval theory. By using the number of standardized index terms and taking account of the relation of index terms, a document information field is constructed. In the new field, the document relevance is computed by field force, so that the new model can get more accurate retrieval results than other models. Experimental results demonstrate its superiority.
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Computer Engineering. 2011, 37(15): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2011.15.043This paper proposes a feature extraction method combining 2D-Gabor wavelet and Kernel Linear Discriminant Analysis(KLDA). The pretreated face images are filtered with multi-scale and multi-orientation, and the filtered images are added into the original face database as separate samples to increase the number of samples. The classical KLDA method is applied to extract features once more to obtain the ideal sample characteristics of class cohesion and between-class scatter. Third-order nearest neighbor classifier is used to classify the features. Experimental results indicate that the method can get a better performance and recognition rate, and it is easy to implement in projects.
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Computer Engineering. 2011, 37(15): 140-142. https://doi.org/10.3969/j.issn.1000-3428.2011.15.044The pilot simulator scheduling problem is a multi-objective and multi-constrained timetable problem. High complexity of the problem makes it impossible to solve it by using traditional Genetic Algorithm(GA). This paper proposes an improved GA. The new crossover and reproduction operator, which are redesigned by gene fitness, effectively increases the diversity and the evolution performance of the population. Experimental results based on simulation data and real data show that the improved algorithm can increase the precision of solutions and convergence speed of the population.
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Computer Engineering. 2011, 37(15): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2011.15.045This paper presents a new method for fatigue recognition based on Higher-order Singular Value Decomposition(HOSVD). Facial velocity information, which is determined using optical flow techniques, is used to characterize fatigue. In order to remove the influence of identity, head poses, and lighting conditions, HOSVD is used to extract fatigue features. Experimental results show that the proposed method is effective and attains a satisfactory effect.
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Computer Engineering. 2011, 37(15): 146-148. https://doi.org/10.3969/j.issn.1000-3428.2011.15.046In rainy highway environment, segmentation of vehicle is disturbed by both cast shadow and the water tailing region. For solving this problem, on the analysis of the characteristics of target vehicle, road, shadow and water vapor trailing area, this paper presents a shadow detection method based on color correlation and texture difference. Color correlation is estimated between current pixel and background pixel through dot product of Hue, Saturation, Intensity(HIS) vectors to detect vehicle object and water tailing region. The texture difference based on gradient of current region and background region is calculated to distinguish dark vehicle from cast shadow. Experimental results show that this method can effectively eliminate both the cast shadow and the water tailing region of moving vehicles in rainy highway video, it can ensure the accurate segmentation of vehicle objects.
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Computer Engineering. 2011, 37(15): 149-151,167. https://doi.org/10.3969/j.issn.1000-3428.2011.15.047This paper designs Web authentication system based on voiceprint recognition. An ActiveX control is developed in the browser to record and encapsulate the voice properties of the users and then transfer to the server. In the server side, a Hidden Markov Model(HMM) is designed to represent the Chinese words which are separated by an inserted silence state. And then a stable voiceprint database is constructed after the enough training of speech samples. Actual test results show that this system is suitable for controlling Web resource and has good identification performance and strong portability.
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Computer Engineering. 2011, 37(15): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2011.15.048In order to solve the problem of situation assessment for Uninhabited Aerial Vehicle(UAV) in emergent threats environment, this paper presents a situation assessment model based on Time-varying Bayesian Networks(TVBN). The Posteriori Probability Support Vector Machine (PPSVM) is used to make the uncertain classification of pop-up threat information, and these classification results are used as input information into the assessment model as evidences. Probabilistic reasoning is proposed to complete the situation assessment in dynamic environment. The rationality of the model and the accuracy of situation assessment are verified by simulating the task that the UAV detects the emergent threats.
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Computer Engineering. 2011, 37(15): 155-157,163. https://doi.org/10.3969/j.issn.1000-3428.2011.15.049Aiming at the problem that standard Support Vector Machine(SVM) is sensitive to noise and outliers, by setting the upper bound of loss caused by noise and outliers, this paper presents a robust Support Vector Regression(SVR) based on asymmetric ramp loss function. The concave-convex procedure is employed to transform the associated non-convex optimization problem into a convex one. A Newton method is introduced to solve the robust model. Numerical experiments on the closing price of Hong Kong’s Hang Seng index and Shanghai Stock index show that the model can reduce the noise and the influence of the abnormal values to a certain extent, increase the prediction accuracy and reduce risk of falling to avoid risk.
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Computer Engineering. 2011, 37(15): 158-160. https://doi.org/10.3969/j.issn.1000-3428.2011.15.050An algorithm of detecting the shape of a traffic light in a scene image and the concept of trend table is proposed. It filters and enhances color information in RGB color space by the color feather of traffic light, and gets the candidate areas, segments image using contour tracking algorithm and figures out the chain code. It calculates the matching probability by combining the symmetrical feather and length ratio feather. The discernible scale is determined by the statistics. Experimental results using videos verify the effectiveness of the proposed algorithm.
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Computer Engineering. 2011, 37(15): 161-163. https://doi.org/10.3969/j.issn.1000-3428.2011.15.051A new dynamic adaptive clone selection algorithm is proposed. Mutation probability of each antibody is dynamically calculated. According to antibody affinity, antibody populations are dynamically divided into memory antibody units and general antibody units. Subsequently, antibody populations are adjusted by sphere crossover, so that global search speed of the proposed algorithm is accelerated. Meanwhile, according to larger calculation and longer consumed time, parallel computation technology is introduced into the provided algorithm. The effectiveness and the feasibility of the proposed algorithm are verified by examples. Example shows that the proposed algorithm has less time-consuming and higher convergence precision.
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Computer Engineering. 2011, 37(15): 164-167. https://doi.org/10.3969/j.issn.1000-3428.2011.15.052With complex and diverse language forms, temporal phrases are not perfectly recognized by traditional rule-based method. It is hard to extract an exact match for temporal phrases and recognize the long-distance-dependent temporal phrases representing time with many tokens in Chinese text. To solve these issues, based on the capability to integrate different levels features of Conditional Random Fields(CRFs) model, this paper presents a CRFs-based approach for temporal phrases recognition. By analyzing a set of linguistic features of time phrases in Chinese text such as lexical features, syntactic features and context information, temporal phrases are divided into two types, time-denoting temporal phrases and event-denoting temporal phrases. Three common vocabularies are semi-auto structured as external features. Experimental results show a performance reaching scores of 95.70% for F-measure to time-denoting temporal phrases and 85.75% for F-measure to event-denoting temporal phrases.
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Computer Engineering. 2011, 37(15): 168-170. https://doi.org/10.3969/j.issn.1000-3428.2011.15.053Aiming at the problems that active learning in multi-label classification is slowly, this paper proposes an improved method for multi-label classification which based on average expectation margin. The method by calculating Support Vector Machine(SVM) expectation margin as the selection criteria. Experimental results show that method proposed in this paper outperforms than other active learning strategy based on decision value and posterior probability strategy in terms of classification accuracy or Hamming Loss or Coverage. It can evaluate the unlabeled sample more appropriate, increase the classification accuracy and classification rate more efficient.
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Human Facial Expression Recognition Based on Mixed Features and Hierarchical Nearest Neighbor MethodComputer Engineering. 2011, 37(15): 171-173,176. https://doi.org/10.3969/j.issn.1000-3428.2011.15.054Geometry feature of the mouth is extracted by using Active Shape Model(ASM), and frequency domain feature of the eye and eyebrow is extracted by using Gabor wavelet. According to characteristics of human facial expression, three-layer classification is proposed based on classification tree. The width, the ratio and the difference of width and height of mouth are taken as input of Nearest Neighbor(NN) to train and classify at the first layer. The width and the difference of width and height of mouth are taken as input of NN to train and classify at the second layer. The Gabor wavelet feature of 15 key dots of the eye and eyebrow are taken as input of NN to train and classify at the third layer. The whole identification process is from coarse to fine and combines geometric features and frequency domain features. Experimental results show that the approach is effective.
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Computer Engineering. 2011, 37(15): 174-176. https://doi.org/10.3969/j.issn.1000-3428.2011.15.055The accuracy of Khmer words segmentation for maximum matching algorithm is relatively low, and it is difficult for this algorithm to recognize words that are not enrolled in its dictionary. To solve this problem, an improved Viterbi algorithm is proposed. Wherein automation is used for syllable segmentation, optimization selection and pruning methods are used to promote the segmentation efficiency, and the statistical language model is adopted to perform data smooth for unknown words in this approach. Experimental results indicate that the improved Viterbi algorithm has higher accuracy and efficiency.
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Computer Engineering. 2011, 37(15): 177-180. https://doi.org/10.3969/j.issn.1000-3428.2011.15.056This paper studies the laying strategy of communication network with different objectives. To satisfy different requirements, distance matrix of network terminals is established, and transferred to an undirected weighed graph that is fully connected. According to the network design standard, considering only the shortest distance, model of Minimum Spanning Tree(MST) is developed, and solved with Prim algorithm to obtain the shortest routes. Based on the logical structure of minimum spanning tree, a stability degree constraint model is established and the laying scheme is given. Considering the integrated factors of network laying, Ant Colony Algorithm(ACA) is employed to get the connecting condition with different on-off rate of links, different number of links and maximum network traffic, and to obtain the corresponding laying routes.
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Computer Engineering. 2011, 37(15): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2011.15.057Feature selection is research hotspot in text automatic categorization. Mutual Information(MI) is analyzed. And according to deficiency of MI, Rough Set(RS) is introduced and an attribute reduction algorithm based on relation union theory is proposed. A feature selection method based on MI and the proposed attribute reduction algorithm is presented, and it is suitable for massive text data sets. The method uses MI to select features, and employs the proposed attribute reduction algorithm to eliminate redundancy, so it can acquire the feature subsets which are more representative. Experimental results show that the method is promising.
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Computer Engineering. 2011, 37(15): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2011.15.058Classical fuzzy clustering algorithm has some drawbacks including that the computing of independent variable weights is unreasonable, the set of horizontal section members is slurred, the computational methods of correlation factor are single and so on. In order to solve the problems above, this paper proposes a new algorithm named improved fuzzy clustering algorithm. It uses association analysis to compute the independent variable weights, sets up a method warehouse and uses it to calculate the correlation factors, and selects distinct members of the equivalent matrix as the set of horizontal section. Experimental result demonstrates that the new algorithm increases the accuracy of forecast.
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Computer Engineering. 2011, 37(15): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2011.15.059This paper proposes a background modeling approach based on self-adaptive learning rat aiming at the update of the learning rate about Gaussian mixture model. The initial background is established using the traditional Gaussian mixture model with a global learning rate. The self-adaptive learning rate is used for each pixel according to the number of matching when the background is updated. Experimental results show that compared with moving object detection approach based on conventional Gaussian mixture model, it has a desirable stability and learning ability.
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Computer Engineering. 2011, 37(15): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2011.15.060Because of the traditional edge detection inadequacy, quaternion’s vector rotating theory is used, improved particle swarm algorithm is introduced to quaternion edge detection. A new color image edge detection method is presented. Experimental results show that the proposed method of color image edge detection has good effect. It can extract the image detail, and the algorithm is stable, easy to convergence, edge detection a little faster.
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Computer Engineering. 2011, 37(15): 193-194. https://doi.org/10.3969/j.issn.1000-3428.2011.15.061A novel image colorization algorithm based on genetic algorithm is proposed aiming at overcoming unsatisfactory and inefficiency in the traditional colorization algorithm. Initialization of the chromosomes is introduced in the proposed method and then the luminance feature and Tamura texture feature of object block image and source block image are adopted as the fitness function, with which basic principles of nature evolution, selection, crossover and mutation are applied. The colorized image is effectively acquired by transferring the color from source block images to matched object block images. Simulation results show that the proposed algorithm outperforms previous method in speeding up the colorization process and meanwhile improving the image quality.
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Computer Engineering. 2011, 37(15): 195-196. https://doi.org/10.3969/j.issn.1000-3428.2011.15.062In order to synthesize new characters with components on the existing inscription on Yan Qin-Li stele, it is necessary to handle Chinese word components. Current mainstream image processing software can not bold and refine the components horizontally and vertically. This paper puts forward a rotary algorithm to achieve the expansion, refinement and optimization of the components. This rotary algorithm solves the serious distortion of component images after rotating components many times, which can not be achieved with general algorithms. YAN Qin-Li stele character software based on this algorithm can bold and thin the strokes horizontally and vertically, and rotate the components through artificial fine-adjustment, so as to synthesize new characters of the calligraphy style of Yan for the effect of being harmonious, attractive and beautiful.
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Computer Engineering. 2011, 37(15): 197-200. https://doi.org/10.3969/j.issn.1000-3428.2011.15.063This paper studies the parallel algorithm for image segmentation under multi-core environment. It combines the multiresolution image pyramid based on the orthogonal wavelet decomposition with the Fuzzy C-means(FCM) clustering algorithm, and achieves the multi-processor and multi-threaded parallel model of P-FCM with the parallel language of OpenMP. It gives the algorithm implementation of the model. For the original image data preprocessing, the parallel method of rectangular block is used to divide the original image data into sub-rectangular data blocks, which will be used as the input data and assigned to different processor by the mater thread for the parallel computing. Experimental results show that, in dealing with the large size images, this algorithm has high efficiency.
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Computer Engineering. 2011, 37(15): 201-202,211. https://doi.org/10.3969/j.issn.1000-3428.2011.15.064Correlation matching tracking algorithm based on pixel gray and character is commonly used. The algorithm based on edge feature is a research hotspot because of its advantages for application. However, this kind of algorithm can just locate to integer pixel for its low tracking precision. A method based on the quadratic surface fitting is selected for subpixel matching through analysis and comparison. A new experiment is designed to show that this algorithm gets as high as 0.1 level of pixel location precision.
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Computer Engineering. 2011, 37(15): 203-204,217. https://doi.org/10.3969/j.issn.1000-3428.2011.15.065When the variance between the largest category(Otsu) is used in noise image, Otsu method can not provide satisfactory results. Under this situation, this paper proposes a new noisy remote sense image segmentation method. The method applies wavelet package transform to decompose the remote image. The noises in the remote image are eliminated by the adaptive threshold method. Otsu method is adopted to segment image. Simulation experiments show that the algorithm has better immunity to noise and achieves good performance in segmentation quality.
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Computer Engineering. 2011, 37(15): 205-207,220. https://doi.org/10.3969/j.issn.1000-3428.2011.15.066Considering the widely used CAPTCHA on Internet is still at the risk of low security, a novel automated correction algorithm for declining numbers is proposed from the angle of recognition, through which can automatically find the bottom and azimuth tilt of the characters. The algorithm involves three aspects which are the coordinate of digital numbers, channel search and channel analysis. Among them, the first step which based on the early preprocessing process can be used to verify the tilt while the channel search process determines the connection of the characters and provides information for the channel analysis stage. Experimental results show that it can reach nearly 100% accuracy of the correction rate for standard characters and 95% of the average recognition rate for characters with micro-deformation.
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Computer Engineering. 2011, 37(15): 208-211. https://doi.org/10.3969/j.issn.1000-3428.2011.15.067This paper proposes a rate control MGS optimization model based on greedy algorithm, which works in low complexity. The importance of each MGS slice layer is expected, and different rate-distortion models are proposed according to the frame type and quality layer type. The optimization scheme for MGS slices based on greedy algorithm is proposed. Experimental results show that the method distinctly improves decoded image quality, its average PSNR increases 0.5 db.
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Computer Engineering. 2011, 37(15): 212-214. https://doi.org/10.3969/j.issn.1000-3428.2011.15.068Most of the researches in extracting semantic concepts do not consider the temporal associated co-occurrence characteristic of multimodes, and label the training set using self-define concepts, thus affecting the accuracy of semantic concepts extraction. Aiming at these problems, this paper brings forward a new approach based on Simfusion algorithm and labeling the training set using ontology repository to extract semantic concepts of video. The method extracts key-frame according to the content of the shots, and makes the most of temporal associated co-occurrence characteristic during in multimode. Meanwhile, the method labels the sample set using the ontology repository and training classifier, thus offsetting insufficiency in subjectivity, incorrect. Experimental result shows that the method can get a better accuracy, well operability and universality in the research of semantic concepts of video.
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Computer Engineering. 2011, 37(15): 215-217. https://doi.org/10.3969/j.issn.1000-3428.2011.15.069This paper gives a detailed survey of the understanding of similarity video clips, the matching of similarity video clips and the detection of similarity video clips in videos events. And emphasizes on the presentation of kinds of video matching technology during similarity video detection, and discusses the advantages and limitations among them. The popular technologies in the detection are introduced. Combining with actual applications, the existing problems and potential tendency of these research directions are discussed.
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Computer Engineering. 2011, 37(15): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2011.15.070The exponential-Golomb code is a important part of entropy encoding in AVS video compression standard. This paper investigates the characteristics, encoding and decoding algorithm of exponential-Golomb code, and presents a new algorithm for Exponential-Golomb encoding and decoding according to the mathematic relation between binary value of exponential-Golomb code. Especially in exponential-Golomb decoding, the algorithm discards the idea of reading and judgement bit-by-bit, uses the method of 32 bit reading and given formula. Experimental result shows that the exponential-Golomb code algorithm shortens the encoding time by about 10% than the algorithm applied in AVS reference software, and shortens the decoding time by about 30% than the algorithm applied in AVS reference software.
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Computer Engineering. 2011, 37(15): 221-223. https://doi.org/10.3969/j.issn.1000-3428.2011.15.071For global motion estimation process is often accompanied by the influence of local campaign, this paper puts forward a global motion estimation algorithm based on LMedS&LS. It gets the corresponding characteristics of the coordinates of the piece from two adjacent frames, uses it in affine transformation model, estimates the global motion parameters, and completes image registration through the bilinear interpolation according to the motion parameters. Experiments show that compared with LMedS algorithm, it is improved in both the accuracy and effectiveness.
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Computer Engineering. 2011, 37(15): 224-225. https://doi.org/10.3969/j.issn.1000-3428.2011.15.072In order to reduce the high coding complexity in H.264/AVC, this paper proposes an improved direction detection mode selection algorithm to improve the encoding efficiency. The proposed algorithm takes advantage of the correlation in temporal and spatial domain and simplifies the DC mode. Experimental result shows that the proposed method can reduce the encoding time by 70% with negligible coding loss, and it reduces the Rate Distortion Optimization(RDO) calculations.
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Computer Engineering. 2011, 37(15): 226-227,231. https://doi.org/10.3969/j.issn.1000-3428.2011.15.073To satisfy high-rate mass-capacity data recording, a novelty record device is introduced by the paper based on FLASH. The method to operate FLASH array and the skill about high-rate record are described. Based on Universal Serial Bus(USB) and FPGA technique, several FLASH slices work together controlled by FPGA to complete high-rate mass-capacity. The design utilizes module method and pipelining technology. Simulation result shows that the system can achieve data recording speed of 80 MB/s, data playback speed of 20 MB/s, storage capacity of 256 GB.
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Computer Engineering. 2011, 37(15): 228-231. https://doi.org/10.3969/j.issn.1000-3428.2011.15.074This paper studies the distributed collaborative simulation between Adams virtual prototype and Simulink control module. A distributed simulation environment of inter-discipline can be constructed based on High Level Architecture(HLA) technology. A virtual prototype model and a Simulink control module can be encapsulated in their federation member and carried out distributed collaborative simulation on the support of Run-time Infrastructure(RTI). An example is given which verifies this method.
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Computer Engineering. 2011, 37(15): 232-234,237. https://doi.org/10.3969/j.issn.1000-3428.2011.15.075The ISO15765 protocol is analyzed, the development of CAN network layer protocol stack is achieved by the platform of vehicle control unit which is based on MC9S12DP512, meanwhile, the development process is given in detail. Under the VC environment, test procedures are developed for the test of the protocol stack. The results show that the protocol stack is in accord with ISO15765, and meets CAN network layer communications needs in variety applications, such as vehicle fault diagnosis system.
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Computer Engineering. 2011, 37(15): 235-237. https://doi.org/10.3969/j.issn.1000-3428.2011.15.076In order to achieve gearbox fault online detection, the method of gearbox vibration signal online identification based on recursive AR model parameters identification is presented. The different condition vibration signals of the laboratory gearbox are detected. Then the order of auto-regression model and the initial values of model parameters are determined by the optimal instrumental variable approach for these detect signals. On these foundations, recursive parameter online identification based on Kalman filter is implemented taking coefficients of the auto-regression model as the states variables. Meanwhile, gearbox fault online detection is realized depends on the 2-norm of model parameters change. And two kinds of faults that peeling off the bearing outer ring and gear wear are analyzed. Results show that their 2-norm of model parameters change for two failures happened mutation.
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Computer Engineering. 2011, 37(15): 238-239,242. https://doi.org/10.3969/j.issn.1000-3428.2011.15.077For the problems that the RapidIO controller with many Cyclic Redundancy Code(CRC) will increase the area and power, this paper designs a new CRC module with four CRC16 generators, which work at the same time. The new CRC module can output the check code ahead of the previous work for one cycle. Results of power evaluation show that compared with the previous work, the number of logical gates, the area, and the power of this design are respectively decreased by 10.8%, 18.9%, and 25.3%.
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Computer Engineering. 2011, 37(15): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2011.15.078This paper presents a scheme of digital receiver for Ultra-high Frequency(UHF) Radio Frequency Identification(RFID) reader. Backscattered signals of passive RFID tags have various energy levels and large frequency variation, which can be handled by power detector, digital phase lock loop and differential decoding. The receiver is simulated in Matlab and implemented on Xilinx Spartan3E platform. Compared with conventional RFID receiver utilizing multiple correlation banks, the scheme achieves better performance with less hardware cost.
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Computer Engineering. 2011, 37(15): 243-245. https://doi.org/10.3969/j.issn.1000-3428.2011.15.079To make it easy and efficient internal mechanism for complex adaptive system and improve modeling capabilities of computer, a new modeling method is proposed based on combination of Time Petri Nets(TPN) and multi-Agent. In the method, Agent is used as basic modeling element and Petri nets are used to describe the internal rules of Agent, the model of complex adaptive system is established based on the combination of Petri nets and multi-Agent in the system, so that, the space explosion of the Petri nets model is prevented and the rules restriction of the Agent is avoided. According to the equipment technological parameters and the analysis of steel rolling system, the simulation model of the logistics system in steel rolling process is built by OPEMCSS package based on multi-Agent. The results show the system model can represent the facts of the complex adaptive system.
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Computer Engineering. 2011, 37(15): 246-248. https://doi.org/10.3969/j.issn.1000-3428.2011.15.080X86 simulation on heterogeneous processor platform suffer from low performance and other problems. To address these problems, a high performance I/O architecture is presented. This paper describes the design and implementations on bus and interface function, bridge chipset and interrupt system in details. SPEC2000 benchmark test result shows that this I/O architecture’s performance is higher than the software simulation technology. The performance is promoted by 10%~20%.
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Computer Engineering. 2011, 37(15): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2011.15.081By the analysis of the architectures of parallel computer, an embedded data parallel computer architecture model is proposed for multimedia processing applications. The limitations of high communication complexity and weak adaptability of the conventional PIM architectures is bridged by this model combined the PIM technology with the reconfigurable bus. The main components and the instruction set are described in detail. A typical algorithm example is given to show the composition of assembly language program and the process of parallel computation.
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Computer Engineering. 2011, 37(15): 252-255. https://doi.org/10.3969/j.issn.1000-3428.2011.15.082Aiming at the composing and characteristics of current air defense combat, based on the entity model of ground-to-air missile battalion firepower simulation system, put forward HLA development process based on UML. It designs a method of improved fuzzy Analytic Hierarchy Process(AHP) to calculate synthetic credibility of this system. It also designs the federation of the simulation system, which promotes the impersonality and speediness. The test results indicate that this simulation system is quickly and credible, saves train budget, and provides assistance decision method to promote the deployment of fire unit and battle effect.
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Computer Engineering. 2011, 37(15): 256-258. https://doi.org/10.3969/j.issn.1000-3428.2011.15.083This paper analyzes the flow control strategy for Gigabit Ethernet Media Access Controller(GEMAC). For the problems of long PAUSE frame response delay and large buffer preparative space, it adopts an improved flow control strategy based on PAUSE frame. It improves the flow control algorithm and optimizes the buffer space accordingly. Experimental results show that the buffer preparative space is decreased by 42.86% and the rate of buffer utilization is increased by 18.75% by using the improved flow control method.
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Computer Engineering. 2011, 37(15): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2011.15.084This paper proposes an optimization design method for multi-channel broadband phase shifter with constant difference step. It analyzes the phase-shifting network parameters, and builds Particle Swarm Optimization(PSO) algorithm model. The algorithm is designed for system optimization and optimized phase shift network parameters are got. Advanced Design System(ADS) software is used to prove the stability and feasibility of the optimum design result. It shows that this method can satisfy the design specifications quickly and have a stable output of phase-shift network.
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Computer Engineering. 2011, 37(15): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2011.15.085Aiming at the target of protecting File Allocation Table(FAT) file system data security, based on EFI Developer Kit 2(EDK2) open source environment defined by Unified Extensible Firmware Interface(UEFI) specification, this paper proposes a technology of data backup and recovery on firmware level. After using the protocols EDK2 provided for accessing disk partition data. It gets details of files and directories by calculating, and saves them as EFI image file, which will write into destination partition when the recovery module works. Comparing to legacy data backup technology, this technology works on firmware level, is independent of operating system, and this advantage makes it more usable.
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Computer Engineering. 2011, 37(15): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2011.15.086The conception and calculation method of air traffic control system effectiveness are defined in this paper, and the evaluation model which can be used in the air traffic control system of China is proposed, then it evaluates the effectiveness of air traffic control system by the expert survey and Improved Analytic Hierarchy Process(I-AHP) methods. Basing on the effectiveness evaluation model and algorithm, it develops the effectiveness evaluation system, and provides the sensitivity analysis of the factors which can affect the performance of system, results proves the validity of the evaluation system.
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Computer Engineering. 2011, 37(15): 268-270,273. https://doi.org/10.3969/j.issn.1000-3428.2011.15.087To solve the task coordinator setting problem for tactical Command and Control(C2) entities’ collaborative decision-making, this paper proposes the concepts of cooperation quantity between tactical C2 entities, distances of points in cooperation-intercourse network and the spanning tree with the smallest tree height, and gives the algorithm of creating virtual hierarchy(C2 tree) for tactical C2 entities with the smallest tree height. The task coordinator setting method is designed based on C2 tree. An instance is designed to prove the effectiveness of the method.
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Computer Engineering. 2011, 37(15): 271-273. https://doi.org/10.3969/j.issn.1000-3428.2011.15.088In order to help the blind access to the resources of e-books more effectively, this paper proposes a book recommendation method based on users’ behavior. By analyzing users’ logs and considerations of the time factor effect on users’ interests, it proposes a rational behavior model given data of user access to books, book categories and the usage of bookmarks to generate the rational book recommendation for the blind. It helps relief the problem which is caused by user data sparseness in blind digital library. Experimental results show that the algorithm can provide good recommendation results.
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Computer Engineering. 2011, 37(15): 274-275,282. https://doi.org/10.3969/j.issn.1000-3428.2011.15.089One-equation Large Eddy Simulation(LES) model coupled with the bounded and compressed Volume of Fluid(VOF) method is used to simulate the near-field of impulse anti-riots water cannon for studying atomization mechanism of the non-steady jet. The instantaneous isosurfaces of liquid-phase volume fraction and the high-speed photographs are agreed with each other very well in the spray configuration. Through the comparison, the inflation of the high-pressure gas is considered to be the most dominant factor in the near-field.
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Computer Engineering. 2011, 37(15): 276-278,285. https://doi.org/10.3969/j.issn.1000-3428.2011.15.090A location precision model is established by studying the principle of Multilateration(MLAT) system. The relationship between positioning errors and distribution geometry of stations is analyzed. The influencing factors on the position accuracy are simulated in Light of Sight (LOS) through the distribution of inverted triangle station and Star-model station, and then the distribution of the isoline of the Geometric Dilution of Precision(GDOP) is drawed. By the theoretical derivation and the simulating with the detailed data, the different distribution coverage value is shown. At last the optimal distribution layout is presented. Experimental results show that the higher positioning precision can be obtained with these distribution layouts in MLAT system.
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Computer Engineering. 2011, 37(15): 279-282. https://doi.org/10.3969/j.issn.1000-3428.2011.15.091Aiming at the demerits of the lower business and higher power consumption, etc., in constant power dormancy mode of the Long Term Evolution(LTE) system. This paper proposes a variation of power dormancy algorithm at first, which can dynamically change the dormancy period according to the demands of terminal business, promote the standby time of terminal, then, discusses several problems about the average response time and average consumption of the terminal in the dormant state under this algorithm. Simulation experiments show that, compared with constant power dormancy algorithm, the energy consumption can be reduced by 6%~12% in this algorithm.
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Computer Engineering. 2011, 37(15): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2011.15.092Aiming at the problem that, with the development of micro-electronics industrial art, the integration density of circuit is large and the structure is complex, this paper proposes a circuit analysis and optimization method based on complex network theory. Take the benchmark circuits of IBM-PLACE 2.0 as research object. By analyzing the circuit’s degree distribution and clustering coefficient, it finds the circuit having both scale-free and small-world characteristics, then, presents the circuits optimization design method for large-scale integrated circuit. Experimental results show that the optimization method can enhance the robustness and availability factor of large-scale circuit.
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Computer Engineering. 2011, 37(15): 286-287.290. https://doi.org/10.3969/j.issn.1000-3428.2011.15.093In order to solve the fuzziness and uncertainty problems of teaching quality evaluation, a multi-criteria fuzzy synthetic evaluation model is built, and the weights of all indexes are calculated objectively by an improved Analytic Hierarchy Process(AHP) method. A quantitative evaluation method based on arithmetic operations of vague sets is proposed to obtain the result. An example demonstrates the engineering practicability and validity of the model.
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Computer Engineering. 2011, 37(15): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2011.15.094In order to deal with the rubbish information inundation of electronic job market, a service model is proposed with two-way demand. According to the actual demands of recruiters and applicants, the system structure, the data structure and the working flow are given. This paper discusses the demand matching between recruiters and applicants, and mass candidates filtering and the communicating realization issue between agencies. Experimental results show that the model can match and manage both sides information effectively, fasten filtering rate of the resumes.
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Computer Engineering. 2011, 37(15): 291-292,封三. https://doi.org/10.3969/j.issn.1000-3428.2011.15.095Aiming at the situation that existed estimating methods have problems that the accuracy is low, and the estimation scope is small. With the increase of the tag number, the number of time slot must be increased, otherwise the error rate is increased significantly. This paper proposes an estimation method based on geometric distribution and Radio Frequency Identification(RFID) to estimate the tags number. When the method estimates the number of tags, the length of frame can be set to a fixed value, and use Hash function to reduce the deviation of geometric distribution, and then reduce the estimation error rate. Experimental results show that when the time complexity and space complexity is not higher than other algorithm, this method can reduce estimation error rate.
2024
Volume 50 No 3
Volume 50 No 3
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428