20 July 2010, Volume 36 Issue 14
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Computer Engineering. 2010, 36(14): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2010.14.001This paper discusses the current transcoding, proposes a low complexity transcoding structure from H.263 to H.264. The method is based on the principle of the minimum residual energy of motion estimation. Adaptive energy method is layered to reduce the time of inter-frame prediction modes selection on re-motion estimation. Experimental results show that compared with full modes search method, it can save more than 50% of the time. With other fast transcoding algorithms, the method has lower complexity, higher video quality, and a shorter time transcoding.
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Computer Engineering. 2010, 36(14): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2010.14.002For low-cost application of satellite digital TV signal receiving, this paper presents a project of the DVB-S satellite digital TV receiving system on the Godson-based platform. Using the PCI bus on the Godson-2E and fully utilizing the characteristic of the Godson-2E processor for decoding MPEG-2 with high performance, the entire system is designed combined with the special front-end tuner module and the back-end chip which captures the Transport Stream(TS). It proves that the whole system is in line with the DVB-S/MPEG-2 standards and the advantage of the system, such as simple structure, easy realization and low cost, also makes it great value in engineering application for developing the industrialization application of the domestic processors.
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Computer Engineering. 2010, 36(14): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2010.14.003In accordance with the current network congestion problem, this paper introduces the network utility maximization framework on the basis of the optimization theory, where the objective function is the user rates’ utility function and the constraint is the link capacity, as a result the users’ satisfaction is maximized. A distributed rate control asynchronous algorithm is presented based on the duality theory and the Newton-like method is used instead of the gradient method in the link algorithm, and the feedback delay is time varying. Simulation results demonstrate that the algorithm can get the optimal value more quickly and guarantee its fairness.
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Computer Engineering. 2010, 36(14): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2010.14.004Aiming at the problem that the precise definition for Function Points Analysis(FPA) is lacked, there is variation between the metric result and the practice. A clear and unambiguous definition is proposed for counting function points, that is, these counting rules for FPA must be formalized based on B method. Practical example shows that combining B method with software metrics can improve the efficiency of software project management, and provides a basis for automatic functional size measurement.
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Computer Engineering. 2010, 36(14): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2010.14.005For the service reuse problem in pervasive computing, an optimal quality-oriented approach is proposed. The approach achieves service functionality match based on an inverted index, evaluates service quality with the multiple attribute decision making theory, and employs branch and bound algorithm for optimal composition plan generation. Experimental results demonstrate the effectiveness of the proposed approach in improving the quality of generated services.
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Computer Engineering. 2010, 36(14): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2010.14.006Water attainment detection lays the foundation for optimal use of water resource. Wireless sensors are used to sampling water. Data of sampling is sent by Wireless Sensor Network(WSN) to base station in which data fusion is handled. After receiving the sampling data, the data server implements application decision. Based on a three-level structure of WSN, base station and data server, water attainment sampling algorithms by predicate are designed and simulated. Experimental result shows the practicability and high-efficiency of the algorithm.
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Computer Engineering. 2010, 36(14): 19-21. https://doi.org/10.3969/j.issn.1000-3428.2010.14.007Aiming at the problem that the quality of service in data forwarding plane may suffer heavily caused by slow convergence in Border Gateway Protocol(BGP) routing, based on a simplified BGP routing model and core network topology, this paper puts forward a new MRAI timer setup scheme. The scheme first calculates, then setup according to known network condition. Though simulation software ssfnet test, results show that compared with MRAI timer jitter setup in RFC1771, BGP convergence properties can be improved greatly by the proposed scheme.
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Computer Engineering. 2010, 36(14): 22-23. https://doi.org/10.3969/j.issn.1000-3428.2010.14.008
In view of video frequency frame data in time axis which has Gaussian distribution characteristic, a clustering algorithm based on the measure of Gauss kernel function similarity and an Improved Particle Swarm Optimization(IPSO) is presented. The proposed algorithm can realize accuracy clustering by Gauss kernel function similarity measure, and speed up the clustering process by the IPSO. Experimental results show that the proposed algorithm has greater searching capability and clustering accuracy, which is superior to the C-Mean in analysis of video frequency frame data clustering.
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Computer Engineering. 2010, 36(14): 24-25. https://doi.org/10.3969/j.issn.1000-3428.2010.14.009
Based on the principle of Computational Auditory Scene Analysis(CASA), this paper describes a model of speech separation by analyzing onset and offset of auditory events. The model detects onsets and offsets, and generates segments by matching corresponding onset and offset fronts. The model is evaluated with three kinds of corpus, evaluation shows that it can separate all the corpus with excellent performance.
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Computer Engineering. 2010, 36(14): 26-28. https://doi.org/10.3969/j.issn.1000-3428.2010.14.010Aiming at the high cost of transmitting and preserving for redundancy GML-based spatial data, a compression method is presented. It uses VTD-XML to parse GML document and designs GBW transform which transforms tree structure of GML-based spatial data to two linear structure data. It uses GZip to compress the data and output it. Experimental result indicates it defeats common methods and can improve compression rate of GML-based spatial data efficiency while not needing more compression and de-compression time.
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Computer Engineering. 2010, 36(14): 29-31. https://doi.org/10.3969/j.issn.1000-3428.2010.14.011A method of computation sentence similarity based on concept graph is proposed and the Chinese Frequently Asked Question(FAQ) set system based on concept graph is implemented. The concept graph is used to express users query and candidate questions. The semantic similarities of sentences are computed between users query and candidate questions by semantic similarity based on concept graph. The answer in correspondence with the most similar query is returned to the user. This system can also automatically update and maintain FAQ. Experimental results show the new computing method gets better performance than the keywords-based approach.
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Computer Engineering. 2010, 36(14): 32-33. https://doi.org/10.3969/j.issn.1000-3428.2010.14.012Aiming at the problem that FP-growth algorithm requires two database scans, which are not consistent with efficient data stream processing, this paper presents a novel tree structure which is a variation of FP-tree, called SP-tree, which captures database information with one scan. For making SP-tree have the same compact performance, it presents an efficient dynamic tree restructuring method, called the breadth sorting method, which restructures a frequency-descending prefix-tree branch-by-branch. Experimental results show that compact performance of the SP-tree is better than other prefix-tree structure with one scan.
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Computer Engineering. 2010, 36(14): 34-36. https://doi.org/10.3969/j.issn.1000-3428.2010.14.013
For the load balancing problem of cluster system, an improved dynamic load balancing strategy based on feedback is introduced. Combined with periodic feedback theory, the strategy divides update interval into several equal subintervals, and adopts a random mechanism to distribute requests in each subinterval. The model of the process of cluster system is founded based on queuing theory and the formula for calculating the system performance is obtained. Simulation results show that, compared with Aggressive LI strategy, this strategy can attain equivalent performance at the expense of smaller cost, and has small complexity of implementation.
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Computer Engineering. 2010, 36(14): 37-39. https://doi.org/10.3969/j.issn.1000-3428.2010.14.014According to the high dimensionality and sparsity of rating matrix in traditional collaborative filtering recommendation system, a new collaborative filtering recommendation model based on Local Principle Component Analysis(LPCA) is proposed which combines taxonomy technique and local principle component analysis method to make dimension reduction for different subject genre respectively, and remains the real interested users in one specific subject of the Web pages which accelerates the neighbor searching process. Experiment on real log data indicates the new model can improve the predication quality.
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Computer Engineering. 2010, 36(14): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2010.14.015
In order to solve the problem of grid resource discovery, a grid resource discovery method is presented which is adjusted by preference partition and M-Flooding algorithm. The method gives a new method of measuring resource similarity degree and an improved message diffusion way M-Flooding algorithm. The grid spatial nodes are divided into different groups according to their respective preference attributes. Searching requests are transmitted in groups, which avoids the disadvantages brought by the traditional blind search method. Experimental result shows the method improves the efficiency of grid resource discovery and reduces the average path length of resource discovery.
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Computer Engineering. 2010, 36(14): 43-45. https://doi.org/10.3969/j.issn.1000-3428.2010.14.016This paper presents a rule set model which is used in access control systems and the corresponding model checking algorithm for loopholes which are brought by the rules in access control system. A method which search system states is used to determine if the goals can be achieved under the conditions that some permissions are given by rights. Corresponding strategies are output when the goals are achieved. Experimental results show that the algorithm is efficient in moderate systems.
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Computer Engineering. 2010, 36(14): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2010.14.017To optimize the XML algebra query, this paper uses the cache technology to save the frequently queried XML pattern trees. It can determine whether the pattern trees of request can match the pattern trees in the cache. The results of the matched one can be got from cache directly to improve the query efficiency. It analyzes the rules of pattern match for query and cache, and proves the feasibility and effectiveness of the rules according to the results of experiment.
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Computer Engineering. 2010, 36(14): 49-50. https://doi.org/10.3969/j.issn.1000-3428.2010.14.018Because of the real-time and interactivity, an interactive game needs to call for multimedia data composed by picture, sound and action script as game roles stored on the disk quickly. Aiming at this attribute, a kind of special database management software focusing on interactive games is introduced, and a relational database model, enabled to store and manage multi-media data is built. The method of storing and managing multimedia data by Hash from the two aspects of both physical storage and logic semantic is studied.
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Computer Engineering. 2010, 36(14): 51-53. https://doi.org/10.3969/j.issn.1000-3428.2010.14.019Online data replication is the basic part of disaster-tolerate system. This paper discusses the system architecture and the module architecture of the FreeBSD platform data Replication System(FRS), and presents how these modules cooperate. It designs and implements a FRS which embeds general replication device driver layer. The system has a strong independence, flexibility and versatility, and can achieve replication on data block level while maintain independent on specific storage devices and logical volume manager.
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Computer Engineering. 2010, 36(14): 54-55. https://doi.org/10.3969/j.issn.1000-3428.2010.14.020The statements need to be tested can be decreased by applying the program slicing technology to locate program fault. This paper presents a program fault location method based on critical predicate. The method identifies the critical predicate that can affect the output result, adopts data slicing according to the predicate and fault output statement and introduces the code prioritization technology. It uses the information of data dependences and control dependences and can locate the fault precisely and quickly.
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Computer Engineering. 2010, 36(14): 56-58. https://doi.org/10.3969/j.issn.1000-3428.2010.14.021
This paper analyzes some problems of existing network storage system and presents a basic architecture for out-of-band virtual network storage system based on Enterprise Volume Management System(EVMS) technology. The client, the internal read and write operation, the online expansion of storage capacity, the load balancing, and the asynchronous metadata update algorithms for this out-of-band virtual storage system are designed and implemented.
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Computer Engineering. 2010, 36(14): 59-61. https://doi.org/10.3969/j.issn.1000-3428.2010.14.022A software safety analysis method based on the component-level failure modeling is proposed. By using the extended Failure Propagation and Transformation Notation(FPTN), the failure behaviors of all components are described. It performs the architectural safety analysis by considering the architectural characteristics of various software system components. The safety level can be determined using the correlative fuzzy method. Combining with the example, the failure propagation probability can be obtained, and the results prove the effectiveness of the method.
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Computer Engineering. 2010, 36(14): 62-64. https://doi.org/10.3969/j.issn.1000-3428.2010.14.023Conventional super-sphere retrieval method can not set the retrieval scope into every dimension. Aiming at this problem, a retrieval method based on hypercube area is proposed. High-dimensional data are converted into 1-dimensional index values using clustering-pyramid technique and every index value is identified with an unique mark using locality-preserving Hash function. The P-Chord system is generated. A range query process is given on that basis. Experimental results show that the proposed approach has advantages over reducing the cost of computing distance and the sets of false hits, and improving recall ratio.
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Computer Engineering. 2010, 36(14): 65-66. https://doi.org/10.3969/j.issn.1000-3428.2010.14.024When a distributed storage system stores data, if there are failures of one or several devices, not only the data in the device can not be used, but also the user is unable to visit the resources completely. Aiming at this problem, this paper proposes a fault-tolerance storage scheme based on Reed-Solomon(RS) code, which can restore the faults and realize fault-tolerant when the number of false devices does not exceed m. The scheme has high security and executive efficiency. It can satisfy the requirements of fault-tolerant in storage systems and can be used to construct storage systems which have high reliability requirements.
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Computer Engineering. 2010, 36(14): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2010.14.025Communication among internal systems becomes more and more difficult as enterprise’ scale enlarges, which brings about more problems in the running of operation process. By using the idea of Service-Oriented Architecture(SOA), this paper abstracts components from processes inside the enterprise so that a relationship diagram is gained. And a mathematical model is used to calculate information among processes to gain comprehensive indexes that measure the process. Application proves that the method can make the relationship among internal processes clearer.
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Computer Engineering. 2010, 36(14): 70-73. https://doi.org/10.3969/j.issn.1000-3428.2010.14.026Buffer analysis is one of the most important spatial analysis method in GIS. Based on the fact that existing algorithm is lack of efficiency, this paper presents a random algorithm for buffer generation which can realize parallelization and be implemented easily. It designs several applied modes for SVG visualization to adapt the universality application of buffer analysis, uses Sherwood random algorithm for optimizing computation efficiency and solves the visualization problem by using the mask object of SVG. Testing results prove that this algorithm can increase the efficiency while dealing with large dataset.
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Computer Engineering. 2010, 36(14): 74-76. https://doi.org/10.3969/j.issn.1000-3428.2010.14.027Aiming at the energy overhead caused by monitoring the residual energy of nodes in Wireless Sensor Network(WSN), this paper proposes an improved residual energy monitor mechanism for sensors named Improved Residual Energy Scan(IRES), which establishes the similarity models of both the energy information and the location information, and a data aggregation scheme. Experimental results show that IRES can reduce the quantity of data transmission, decrease energy consumption of nodes, and extend the network lifetime.
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Computer Engineering. 2010, 36(14): 77-78. https://doi.org/10.3969/j.issn.1000-3428.2010.14.028
This paper presents a network traffic matrix estimation method. In the situation of giving the network topology and link traffic, it computes the information entropy according to the link traffic, and utilizes Expectation Maximization(EM) algorithm to compute the traffic demand of the pair of Origin and Destination(OD). The method is evaluated by an experiment on campus networks. Traffic data collected on the backbone network prove that, compared with Generalized Gravity Model(GGM), the method has higher accuracy.
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Computer Engineering. 2010, 36(14): 79-81. https://doi.org/10.3969/j.issn.1000-3428.2010.14.029The establishing of effective incentive mechanisms is one of methods to restrain the selfishness of nodes and improve the system usability of P2P network. The features of P2P network is taken into account, an incentive model for P2P network is proposed in this paper, which comes from rational game. This paper implements the finite state machine of the incentive model. Punishing mechanisms to selfish peers and some essential norms are introduced in this model, which stimulates rational peers to maximize their own utility and contribute their free resource. Analysis and simulation results testify that this model can effectively punish selfish peers, and make them drop selfish behaviors.
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Computer Engineering. 2010, 36(14): 82-83. https://doi.org/10.3969/j.issn.1000-3428.2010.14.030
Wireless mobile node can reduce self access data latency and save bandwidth for whole network by caching data, aiming at this characteristic, this paper improves revenue function of Distributed Greedy Algorithm(DGA). It divides the data access frequency into local access frequency and other node access frequency, and researches the application scenes of different weights. NS2 simulation results show that the efficiency of data caching can be enhanced through reasonably selecting weight in different scenes.
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Computer Engineering. 2010, 36(14): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2010.14.031By referring to the advantage of Teager-Kaiser Operator(TKO), this paper proposes an estimation method for Time Difference of Arrival(TDOA) of two signals based on Cross Teager-Kaiser Energy Operator(CTKEO). TDOA estimation is obtained directly and statistical independently by checking peak position of the similarity between two signals. Simulation experiments with UWB signal show that the method is simple, more achievable and globally outperforms cross-correlation algorithm.
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Computer Engineering. 2010, 36(14): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2010.14.032Aiming at the characteristics of limited energy of sensor nodes and limited communication range in Wireless Sensor Network(WSN), this paper proposes an energy-efficient region-partitioned clustering multihop routing algorithm. By compartmentalizing the network to several regions, the total number of clusters is constant and the clusters can distribute evenly. By constructing tree structures and sequential neighbor lists to select routing nodes, nodes communicate with each other in manner of multihop, so that energy consumption is decreased. Simulation results show that the algorithm can save energy effectively and prolong network lifetime.
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Computer Engineering. 2010, 36(14): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2010.14.033Aiming at the problem that location precision is not high in Wireless Sensor Network(WSN), this paper presents a three-dimensional localization method based on midperpendicular plane segmentation. Segment area in which the node to be localized is segmented into some cubes. It uses midperpendicular plane to eliminate some cubes which are not existing awaiting localization nodes, combines communication radius of anchor nodes to shrink the left area, and gets its centroid of the area as final result. Experimental result shows that the number of anchor nodes is greater than 12, and the error rate maintains at 0.02.
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Computer Engineering. 2010, 36(14): 93-95. https://doi.org/10.3969/j.issn.1000-3428.2010.14.034This paper presents a self-organization coverage algorithm based on virtual force aiming at the Wireless Sensor Network(WSN) nodes which are randomly deployed. It utilizes three kinds of virtual forces including repulsive force, gravity and border constraint force apply to each network node to separate the aggregate nodes, introduces the threshold among nodes and the threshold between node and border to realize maximize coverage of the interested area. Experimental results show that this algorithm can validate coverage area effectively on the base of ensuring connectivity, and it has well utility.
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Computer Engineering. 2010, 36(14): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2010.14.035In Low Earth Orbit(LEO) satellite network, channel handover between satellite and ground causes packets loss to make TCP protocol applied in wired network blindly to generate fast retransmission and weaken the performance of TCP protocol. Aiming at this problem, this paper adds Performance Enhancing Proxy(PEP) model in heterogeneous network, PEP shields the channel switching effect to the source by changing the value of watermark. Theoretical analysis and simulation experiment show that this method brings higher throughput than common TCP with different error rate, and it can avoid the TCP performance decreasing caused by continuous channel switching in short period.
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Computer Engineering. 2010, 36(14): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2010.14.036Aiming to bandwidth-constrained and energy-constrained problems in wireless sensor networks, to maximize spectrum utilization and minimize spectrum handoffs, taking the priority and fairness of nodes into consideration, the objective function of maximize-system-performance is constructed. A dynamic spectrum allocation scheme is proposed, which fits the sensor networks effectively. Simulation result shows that the scheme allocates spectrum resources fairly while observing each sensor’s priority and nearly minimal spectrum handoffs.
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Computer Engineering. 2010, 36(14): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2010.14.037
According to the too high density of nodes in Wireless Sensor Networks(WSN) and imbalanced energy consumption of nodes, a distributed coverage control algorithm based on energy(DCCABE) is proposed. This algorithm is based on probabilistic coverage model and computes the area coverage probability of nodes to judge the redundancy according to the sequences which are arranged by the remain energy of nodes and changes the redundant nodes into sleeping state. Simulation results show that DCCABE can effectively reduce the redundancy of nodes and prolong the network lifetime.
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Computer Engineering. 2010, 36(14): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2010.14.038
Single node capability is limited, node in Wireless Sensor Network(WSN) need collaborate with neighbors to complete a task. Aiming at this problem, this paper divides the collaborate task into sensor subtask and computing subtask, and proposes a task collaboration framework based on dynamic coalition and Ant Colony Algorithm(ACO). It chooses the perception node according to the application need, those nodes form an initial dynamic coalition, and assign perception task on the coalition member. When the ratio of perception nodes to the whole nodes is below 32%, the network monitoring performance is best. It adopts self-adaptive ACO to construct data aggregation routing tree, optimizes data transfer path based on strong data relation of a same task, and reduces communication energy consumption.
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Computer Engineering. 2010, 36(14): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2010.14.039
To extract API-calling behaviors from malware and their variants effectively, this paper proposes an approach to statically detect the obfuscated API-calling behaviors in Windows platform. In this approach, instruction pattern matching is used to recognize the special calling manner. The relationship between the targets of call instructions and the name strings of API functions is analyzed to identify which API function is called actually. Experimental results show that using this approach can improve detection ability of static analysis tools through static analysis.
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Computer Engineering. 2010, 36(14): 111-113. https://doi.org/10.3969/j.issn.1000-3428.2010.14.040
In the game of attack and defense, semi-distributed P2P botnet becomes the most dominant form of botnet as the applications of P2P are widely used. This paper describes the basic principle of how the attackers create their semi-distributed botnet and the model of its increasing, proposes the “faked honeypot” detection model, which combines honeypot and the flow analysis. When anomalies appear in host network, the programs and services are closed, the host is made to lay aboard to the honeypot, and detected by flow analysis. Experimental result shows that the method can effectively improve the detection rate of semi-distributed P2P botnet.
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Computer Engineering. 2010, 36(14): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2010.14.041On the assumption that mobile code is composed of functions, a function embedding algorithm is proposed to check computational integrity. An algebraic homomorphism encryption algorithm is proposed to encrypt the function embedding algorithm. The algebraic homomorphism can resist known plaintext attacks. Based on the above two algorithms, a protocol for checking computational integrity and protecting confidentiality is proposed. The protocol couples the checking functions with the normal computed functions, so that the checking functions can not be deleted. It is easy to be constructed and implemented.
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Computer Engineering. 2010, 36(14): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2010.14.042Through the analysis of key requirements, a key generation system for the integrated network of Internet and WSN is designed on the basis of Combined Public Key(CPK) algorithm. Each part of the system is depicted. According to the node’s identity, a combined mapping key is generated by advantage of high-precision TOM Mathlib on VC++ 6.0. In this system, the secret key is stored in the node in term of ID certificate. It can support a network in a large scale with only 50 KB seed matrix storage in Key Management Center(KMC) which has strong scalability.
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Computer Engineering. 2010, 36(14): 120-121. https://doi.org/10.3969/j.issn.1000-3428.2010.14.043This paper introduces a self-adaptive gray image encryption algorithm to encrypt color images. In terms of two flaws including dissatisfied security and low efficiency, Coupled Map Lattice(CML) and AMS transformation are adopted to make up the deficiencies. Theoretical analysis and simulation experiment demonstrate the simplicity and high speed of the algorithm. It can be used in the actual parallel computing platform with high security.
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Computer Engineering. 2010, 36(14): 122-123. https://doi.org/10.3969/j.issn.1000-3428.2010.14.044
This paper proposes a forward security proxy multi-signature scheme on the basis of the forward-security idea and proxy multi-signature schemes. The new scheme satisfies security properties of general proxy multi-signature schemes and has forward-security. Under the strong RSA assumption, Diffie-Hellman problem and discrete logarithm problem over finite field, the new scheme has good forward security.
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Computer Engineering. 2010, 36(14): 124-126. https://doi.org/10.3969/j.issn.1000-3428.2010.14.045Yao’s Millionaires’ problem is a typical problem of secure multi-party computation, but most solutions are inefficient. Based on commutative encryption scheme, this paper proposes an efficient and secure solution to millionaires’ problem, which reduces the problem to the set- intersection problem by 0-encoding and 1-encoding for private inputs. Proof of security is followed. There is no complicated modular exponentiation in this solution which only needs O(n) encryption/decryption and 4 rounds of communication. It is more efficient than other solutions.
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Computer Engineering. 2010, 36(14): 127-128. https://doi.org/10.3969/j.issn.1000-3428.2010.14.046
In order to protect the computer from the destruction of the unknown malicious software, this paper carries out the idea of using virtual executing in a simulated system environment to protect computer resources. A lightweight virtual machine is introduced with HOOK to protect critical resources, and a series of API interfaces are provided to make this lightweight virtual machine an open platform available for secondary development. The method successfully identifies new Trojan without feature code.
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Computer Engineering. 2010, 36(14): 129-131. https://doi.org/10.3969/j.issn.1000-3428.2010.14.047
For the characteristics that Mobile Ad Hoc Network(MANET) has no center and the problems that in general distributed authentications, the number of one-jump certificate nodes is less than the threshold, and CA nodes are unreliable, a certificate service scheme in cluster-based architecture is proposed according to multi-layer-cluster architecture and Feldman’s verifiable secret sharing technology. It achieves the distributed authentication at all levels of cluster head and cluster members. The problem that the number of one-hop neighbor certification nodes is less than threshold value is resolved, which prevents malicious nodes working together to recover the secret key of system effectively, and avoids the interior authentication point broken to the distributional authentication disturbance.
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Computer Engineering. 2010, 36(14): 132-134. https://doi.org/10.3969/j.issn.1000-3428.2010.14.048The security leakage of current key management scheme and clustering routing protocols in Wireless Sensor Networks(WSN) is analyzed, and a cluster head selection algorithm based on key connection is proposed. It takes the number of keys shared between cluster head and cluster nodes as the important index, using the fuzzy inference system. Unlike to the traditional fuzzy inference algorithm, the algorithm achieves a good combination between the clustering routing protocols and key management schemes, effectively lowering and balancing the communication energy in a cluster and improving the communication security compared with the typical clustering algorithm.
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Computer Engineering. 2010, 36(14): 135-137. https://doi.org/10.3969/j.issn.1000-3428.2010.14.049In the automatic malicious code analysis system, the first step is the file format analysis of malicious code and detect whether it is packed. For detecting the packed PE files more accurately, NFPS, which is a packed PE file detection rule based on the file header and many parts of content, is proposed. Through extracting five characteristics of PE files and calculating them based on NFPS rule, it can detect the packed PE files accurately. Through the test, the rate of detection accuracy of NFPS can reach more than 95%, and it can support loop detection of multilayer packed PE files.
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Computer Engineering. 2010, 36(14): 138-140. https://doi.org/10.3969/j.issn.1000-3428.2010.14.050Considering the computer network as an integrated unit, the effect of the system’s topological characteristics on the prevalence of virus is analyzed by using the small world network theory, and the rules which can describe the safe sensitivity of the network nodes are proposed. The virus grade diffusion model based on the small world clustering is established and the propagation intensity between the nodes is decided. The virus propagation paths with high risk and corresponding crisp nodes are found with ant colony algorithm, which plays a key role in the network safety prevention.
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Computer Engineering. 2010, 36(14): 141-143. https://doi.org/10.3969/j.issn.1000-3428.2010.14.051
Currently there are few tripartite Authenticated Key Exchange(AKE) protocols which have a formal security proof. Aiming at this problem, this paper investigates the security model for the tripartite AKE protocols. A strong security model named enhanced Canetti- Krawczyk(eCK) model for two-party AKE protocols is proposed. A strong security model for three-party AKE protocols is introduced which generalizes the eCK model for two-party setting, and the insider attack is taken into account. It presents a new tripartite AKE protocol and shows that the protocol is provably secure in the strong security model.
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Computer Engineering. 2010, 36(14): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2010.14.052For dealing with the “Small Sample Size(SSS)” problem in face recognition tasks, regularized Linear Discriminant Analysis(LDA) based on ensemble learning is proposed. By using Adaboost method, weighting function is introduced into the samples, which is closer in the output space in each iteration. So that the separability between these classes is enhanced in the new feature subspace, and the recognition rate is also improved to 98.5%. Experimental results on facial database of ORL show that this method achieves better performance than traditional methods do.
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Computer Engineering. 2010, 36(14): 147-149. https://doi.org/10.3969/j.issn.1000-3428.2010.14.053A genetic algorithm to handle constrained optimization problem is proposed. This method searches the decision space of a problem through the arithmetic crossover of feasible and infeasible solutions, and performs a selection on feasible and infeasible populations respectively according to fitness and constraint violation. It uses the boundary mutation on feasible solutions and the non-uniform mutation on infeasible solutions because the solutions usually deviate from the constraint domain after the traditional mutation operation. It maintains the population diversity through dimension mutation. Numerical results show that it is an effective algorithm.
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Computer Engineering. 2010, 36(14): 150-152. https://doi.org/10.3969/j.issn.1000-3428.2010.14.054
According to the theory of consistency fault diagnosis based on first theory, the max-normal diagnosis theory based on dimidiate- consistent test is proposed. It integrates the kernel theory of consistent fault diagnosis and abductive diagnosis, not only makes up the weakness to construct the conflict set in intelligent fault diagnosis based on model, but also decreases the number of the objects in the consistency test and shrinks the space of diagnosis. Diagnostic accuracy is so greatly improved, the theory has better application. Application example proves the efficiency of this theory.
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Computer Engineering. 2010, 36(14): 153-155. https://doi.org/10.3969/j.issn.1000-3428.2010.14.055This paper introduces a method to realize the neural network to a product fast by using Matlab and other program tools to combine programming, presents some problems and solution, such as the creation of classic BP neural network, the integrated C code exporting, and the combination with Linux/Qt programs. Using this method can deploy the BP neural network algorithm to the embedded system or personal PC, it not only has good runtime effectiveness, but also can greatly reduce the cost and development time.
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Computer Engineering. 2010, 36(14): 156-157. https://doi.org/10.3969/j.issn.1000-3428.2010.14.056This paper utilizes population memory and proposes a Population Mnemonic Algorithm(PMA) for evolutionary computation. PMA thinks about population individual current more diverse population and the diversity weight w1. With multi-dimensional optimization and fixed evolutionary generations, this paper tests the algorithm by using Rastrigrin function, Griewangk function, and Schwefel function. benchmark shows that PMA is better than Chaos inertance weight PSO(CPSO) algorithm.
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Computer Engineering. 2010, 36(14): 158-160. https://doi.org/10.3969/j.issn.1000-3428.2010.14.057Aiming at the problem of low efficiency of the forensic analysis method based on the association rule, this paper proposes an immune clone forensic analysis method with constraint. Taking the support of the antigen to the antibody as the function of affinity, taking the key attribute as the constraint condition and taking the minimal support and the minimal confidence as the screening condition, the behavior profiling is built with the help of the immune clonal operation. Experimental result shows that compared with forensic analysis method based on Apriori-CGA algorithm, the setting up time of behavior profiling and the scale of behavior profiling of the method are remarkably reduced, it can effectively improve the efficiency of forensic analysis and confirm the range of electronic crime investigation.
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Computer Engineering. 2010, 36(14): 161-162. https://doi.org/10.3969/j.issn.1000-3428.2010.14.058
Eyes location is the priority of iris identification, eye tracking and state recognition. A method for eyes location based on maximum entropy segmentation and skin model is proposed. Image segmentation based on maximum entropy is used to segment the image and candidate regions of eyes are obtained. YCbCr skin model is built as constraint condition of eyes location, and morphological operations are used to obtain precise eyes location. Simulations show that this method can not only precisely and fast locate eyes position, but also adapt to process the image in different background, such as head existing rotation and image itself contain details.
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Computer Engineering. 2010, 36(14): 163-165. https://doi.org/10.3969/j.issn.1000-3428.2010.14.059Selecting an optimal subset of classifiers from overproduced candidates is a key step when the “test-and-select” method is employed to design a multiple classifier system. This paper therefore defines a new concept——Degree of Combination Fitness(DCF) and presents a new DCF-based classifier selection method. In its application to experiments of hyperspectral data classification, the new method selects a subset from a pool of twenty-seven candidate classifiers. Results show that in comparison to other popular methods, the proposed method has advantages both in efficiency and recognition accuracy. Besides, it can guarantee the generalization ability of the selected set as well.
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Computer Engineering. 2010, 36(14): 166-168. https://doi.org/10.3969/j.issn.1000-3428.2010.14.060This paper presents an improved ant colony algorithm for solving Nash equilibrium of n persons’ non-cooperative games, using the basic principle of ACO algorithm. In the global search phase, crossover operation and mutation operation of GA are incorporated to improve global exploring ability. During the local search phase, dynamic random search technique is embedded to accelerate the convergence to the optimal solution, and the random search vector is adjusted by controlling step length to ensure search in the mixed strategy profile space. Numerical experiments show that the proposed algorithm has better performance than the traditional genetic algorithm.
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Computer Engineering. 2010, 36(14): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2010.14.061For speech recognition network of Hidden Markov Model ToolKit(HTK) bottom representation is generated by the HParse command module of the HTK according to the form of regular expressions to define the task grammar, but not every language can use regular expressions to express. Aiming at the problem, this paper presents a HTK-based speech recognition network algorithm used to identify the network optimization problem, gives the detailed realization of the algorithm. Experimental results show that the optimized speech recognition network costs less time in speech recognition than the original un-optimized one, while the recognition rate of the two recognition system configurations are almost the same, and verifies the validity of the proposed algorithm.
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Computer Engineering. 2010, 36(14): 172-173. https://doi.org/10.3969/j.issn.1000-3428.2010.14.062An adaptive fidelity total variation image smoothing model is proposed. The proof of the stability of solution for this model is given. The method combines the merits of isotropic and total variation. A fidelity term constructed by the diffusion coefficient is used to enhance the edge of the image. The thresholds are introduced based on the gradient information of image, which helps the model to choose the appropriate smoothing scheme. This model removes noises highly and retains sharp edges without exhibiting staircasing. Experimental results show this model is succeessful in overcoming staircasing and efficiently removing noise, and the PSNR is high.
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Computer Engineering. 2010, 36(14): 174-176. https://doi.org/10.3969/j.issn.1000-3428.2010.14.063A method for generating the depth image from multi-view images based on color segmentation is presented. Mean-shift algorithm is used to extract homogenous regions in the reference image. The initial disparity maps applying local window-based matching algorithm is got. According to certain criteria, these initial depth maps are merged into one disparity map to improve the quality of disparity map, and optimized the disparity map by post processing. The disparity map is converted to a depth map. The algorithm can deal with the occlusion problem effectively, which increases the matching accuracy, and improves the quality of the disparity map.
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Computer Engineering. 2010, 36(14): 177-178. https://doi.org/10.3969/j.issn.1000-3428.2010.14.064This paper presents an HMT model based on the module of the coefficient in Pyramidal Dual-Tree Directional Filter Bank(PDTDFB). The features of the PDTDFB theory, the module of the complex coefficient and the HMT are combined in this model. The HMT model based on the module of the complex coefficient obtained by PDTDFB decomposition is established. It trains the model by the EM algorithm to denoise and obtain the module, and restores the complex coefficient and reconstructing image. Compared with the other typical denoising methods, experimental results demonstrate that the effects raise in different degrees in image denoising, especially in edge maintenance aspect.
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Computer Engineering. 2010, 36(14): 179-181. https://doi.org/10.3969/j.issn.1000-3428.2010.14.065Aiming at limitation of classical methods of color image sharpening, a kind of novel spatial sharpening algorithm is proposed, which includes mathematical morphology. Gaussian filter is used to separate low frequency and high frequency components of image. High frequency component is intensified, low frequency component is modulated, and the two components are composed into new output image. Morphology open and close operations are composed to apply to high frequency component of image because the two operations have separately adaptive maximum and minimum filtering feature, consequently local detail of image is automatically highlighted. Then modulated transfer function model of human eye is adopted to low frequency of image, and whole visual appearance of image is further improved. Experimental results show that the method is better than classical image sharpening algorithms in RGB color space and hue/illuminant/saturation perceptional color space.
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Computer Engineering. 2010, 36(14): 182-184. https://doi.org/10.3969/j.issn.1000-3428.2010.14.066According to degraded phenomena of outdoor video images taken in foggy weather, this paper proposes an entirely self-adapting method of video image restoration on the basis of atmospheric model. Under the gray distributing characteristic of an image, the optimal normal distribution of the gray for sky region can be gained. The gray mean of the sky distribution can be obtained by the optimal normal distribution. At the same time, the iso-depth region can also be segmented according to the gray histogram and the value of normalized radiance can be solved. It uses contrast of pixels in iso-depth region to realize restoration of degraded images. Experiments show the method can effectively improve degraded images in foggy weather.
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Computer Engineering. 2010, 36(14): 185-186. https://doi.org/10.3969/j.issn.1000-3428.2010.14.067Based on the properties of Nonsubsampled Contourlet Transform(NSCT), shift invariance, multiscales and multidirectional expansion, a novel image denoising method based on NSCT and P-Laplace diffusion is proposed. This method is able to inherit not only the ability of NSCT to catch the edge information but also the ability of P-Laplace proliferation to keep the edge information of an image. Simulation analysis and experimental results indicate that the proposed method outperforms the others in terms of visual quality and maintains much more detail information as well.
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Computer Engineering. 2010, 36(14): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2010.14.068
Aiming at the problems that there exists edge vague, the pseudo-edge cannot be removed and algorithm results do not achieve optimal results by virtue of fuzzy reasoning for edge detection algorithms, this paper proposes an improved fuzzy edge detection algorithm. It proposes a fuzzy rule that uses the contrast of gray-scale’s direction to determine the value of edge’s membership and increase the rules to remove false edge and make edge refined. Tests show that the algorithm is better than fuzzy competitive algorithm, Pal King algorithm and other improved fuzzy edge detection algorithms.
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Computer Engineering. 2010, 36(14): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2010.14.069A new method of image quality assessment based on Structural Similarity(SSIM) and Human Vision System(HVS), called CT-SSIM is proposed. The frequency band property of different direction of Contourlet Transform(CT) is used. It also uses the character of CT coefficient. Theory analysis and experimental results show the CT-SSIM is more accurate and has better correlation with the subjective assessment of human beings. It can assess image quality better.
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Computer Engineering. 2010, 36(14): 193-195. https://doi.org/10.3969/j.issn.1000-3428.2010.14.070Aiming at the problem that the underwater acoustic image is often divided into light areas, dark areas and reverberation areas, while it is unable to obtain the corresponding region through the traditional single thresholding method, the image segmentation based on the maximum entropy of the amended gray-gradient 2D histogram method is proposed. In this method, priori knowledge is used to intercept part of the gray- gradient 2D histogram, which is segmented through the maximum entropy. Experimental results demonstrate that the interested region can be distilled as needed, and better segmentation results can be achieved by adopting this method in acoustic image segmentation.
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Computer Engineering. 2010, 36(14): 196-197. https://doi.org/10.3969/j.issn.1000-3428.2010.14.071The threshold of Canny operator relays on the statistics of the image global gradient. The image global gradient differs from local gradient in most cases. Some obvious edge may be neglected while using the same threshold. Aiming at this problem and according to the image entropy, this paper proposes an edge detection algorithm for image partition and applies this algorithm in the Canny operator. Experimental results prove the validity of this method. Its detection effect is better than using Canny operator alone.
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Computer Engineering. 2010, 36(14): 198-200. https://doi.org/10.3969/j.issn.1000-3428.2010.14.072Aiming at the defect of local extreme of traditional mutual information method that computes both big images’ mutual information directly, a registration method that combines mutual information and template matching is presented. The template matching based on similarity criteria of mutual information is carried out, and candidates of sub-images are got, according to spatial relationship between the big image and template and spatial relationship between the big image and candidates. The panorama image after registration is got. After computing mutual information of both big images in the case of every candidate, the final registration is obtained according to maximum of mutual information of both images. Experimental results show this method is robust to images that have great gray scale difference.
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Computer Engineering. 2010, 36(14): 201-203. https://doi.org/10.3969/j.issn.1000-3428.2010.14.073Flow shop scheduling problem is a Non-Polynomial complete problem. This paper presents a new self-adaptive genetic algorithm. Improved methods including compounded initial population, filter stratagem for the individual with same fitness value and improved self-adaptive across aberrance probability are adopted to improve the algorithm performance. The simulation results show that the improved algorithm has high performance in terms of the best result, the relative error of the best results and robustness.
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Computer Engineering. 2010, 36(14): 204-205. https://doi.org/10.3969/j.issn.1000-3428.2010.14.074In multiple instance and threads runtime system, global variables of the component are shared by each instance. When using ActiveX to integrate historical codes, such global variables must be removed by modifying source code. Aiming at this situation, this paper uses the Thread Local Storage(TLS) technology to realize the localization of global variables, and uses the entity simulation codes which have a large number of global variables to realize the encapsulation of ActiveX. The ActiveX implementation is successfully applied in a new generation of Ethernet based multiple channel Computer Numeric Control(CNC) system.
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Computer Engineering. 2010, 36(14): 206-208. https://doi.org/10.3969/j.issn.1000-3428.2010.14.075This paper proposes an interpolation timing recovery model based on τ factor on the basis of improvement in linear interpolation clock recovery model, because traditional servo phase-locked loop timing recovery circuit has the problem of noise interference and long time lock. It conducts the algorithm of interpolator coefficient based on τ factor, researches and simulates the implementation of interpolator by FPGA. Experimental results show that the interpolated timing recovery model based on τ factor can obtain better harmonic frequency and solves the noise problem of traditional harddisk servo timing recovery circuit.
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Computer Engineering. 2010, 36(14): 209-211. https://doi.org/10.3969/j.issn.1000-3428.2010.14.076
Considering the load torque impact on the speed of servo actuator, this paper establishes the model of load torque and proposes a speed circle control algorithm with feedforward fuzzy self-turning Proportional Integral(PI) parameter. It uses feedforward controller to compensate the variational load influence on motor speed. Through dynamic adjustment of control parameter, the controller has good robustness and accuracy when BrushLess DC Motor(BLDCM) characteristics and load torque change. Fuzzy controller is developed by using Digital Signal Processor(DSP) and applying absolute encoder with high accuracy as the feedback of the position loop. Experimental results show that the controller has high robustness, rapid response, small overshoot and high accuracy.
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Computer Engineering. 2010, 36(14): 212-214. https://doi.org/10.3969/j.issn.1000-3428.2010.14.077This paper designs a multi-core sharing SDRAM controller based on network processing, presents a hierarchical priority arbitration algorithm to improve the efficiency of accessing shared memory for the multi-core. For the IP packet processing features, a block data transfer mechanism based on the instruction control is presented, which can shorten the latency of processing IP packet. Priority algorithm and block data transfer mechanism are verified on FPGA platform. Results indicate that processing the IP packet of 64 Byte, SDRAM controller can improve the reading and writing efficiency by 55% at least.
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Computer Engineering. 2010, 36(14): 215-217. https://doi.org/10.3969/j.issn.1000-3428.2010.14.078A high-speed MAC interface data exchange control structure is presented in this paper, it is used for data channel processing of multi-core network processor. This structure uses active request mechanism to control packet receiving, and realize parallel data processing through multi-thread assignment, it maintains packets arriving order as well. Simulation and verification results show the receiver controller module has throughput of 2.56 Gb/s on the frequency of 85 MHz, which meets the performance requirement of network processor for OC-48 line-speed processing.
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Computer Engineering. 2010, 36(14): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2010.14.079
This paper presents a hardware structure-independent weight-based fault injection model for accurate emulation of the radioresistance in the SRAM-based FPGA. Fault injection emulation platform based on Joint Test Action Group(JTAG) boundary scan and dynamic partial reconfiguration is proposed. Experimental results show that fault injection system composed of the software model and the hardware platform has high universal property and is more accurate, efficient and needs lower cost emulation.
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Computer Engineering. 2010, 36(14): 221-223. https://doi.org/10.3969/j.issn.1000-3428.2010.14.080
On the basis of analyzing the main task processing strategies of multi-task operating system RTX51, this paper designs and implements a data collecting system based on RTX51. According to the executing sequences, the management of data collecting and interface components in the system are divided into five tasks, between which library function calling is used to send signal to coordinate. Under the control of user keys, field data are preserved after converted, and may be displayed and transmitted to supervisory computer memory. The interface files and functions and mechanism for realization of parallel and sequential tasks are presented. Task schedule with the mechanism realizes data collecting.
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Computer Engineering. 2010, 36(14): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2010.14.081Aiming at the problems that the development of multiprocessor system is difficult and its efficiency is low, this paper proposes a remote debug scheme based on Joint Test Action Group(JTAG) for multiprocessor system. It realizes synchronous and asynchronous debug for multiprocessor, and offers abundant debug means. The multiprocessor debug system is implemented under Linux. Simulation test and practical application demonstrate that the scheme is efficient, and it can improve the efficiency of system development.
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Computer Engineering. 2010, 36(14): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2010.14.082
The approach of modularity, proposed by Newman and Girvan in order to measure the satisfaction with network decomposition, is found not suitable to the evaluation of community structure in networks when the number of links incident to each community differs too much. To resolve this problem, this paper presents a new modularity approach based on the concepts of linking density and cohesion of communities. Through both theoretical and empirical studies, the modularity is applicable to all cases including the networks with communities having nearly the same number of incident links and the networks when the number of links incident to each community differs too much.
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Computer Engineering. 2010, 36(14): 230-232. https://doi.org/10.3969/j.issn.1000-3428.2010.14.083Aiming at the problems of complex process, lacking unified sort in existing multi-mode Phased Mission System(PMS), based on minimal cut set, this paper presents a multi-mode PMS simulation model based on Extend. Under the condition knowing basic equipment failure distribution function, it expresses logical relation of various phases through structure function, and deals with the relation of phases dependency and modes dependency relation by utilizing the idea of statistical sampling. It can make modeling analytical process more simple based on ensuring small and stable of reliability by using this model to solve PMS than DEP-BDD parse algorithm.
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Computer Engineering. 2010, 36(14): 233-234. https://doi.org/10.3969/j.issn.1000-3428.2010.14.084Starting from the characteristics of protein structures, a new method based on structure alphabet and Chaos Game Representation(CGR) is provided. Its can find the main structure of the protein easily by CGR, and make use of CGR and Hausdorff distance to complete protein similarity comparison. Compared with other methods based on amino acid sequence, this method can resolve the problem that different proteins are classified into one family just for the similar sequence of amino acid. The proteins with similar sequence of amino acid may be belong to different protein families, because they have different structures. The functions of protein depend on their structures, so this method can get better result of similarity compared with that of amino acid sequence.
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Computer Engineering. 2010, 36(14): 235-237. https://doi.org/10.3969/j.issn.1000-3428.2010.14.085In order to study the characteristics of FlexRay and FlexRay clock synchronization algorithm, this paper introduces the basic features of FlexRay, as well as the basic process of FlexRay clock synchronization, and introduces the Fault-Tolerant Mid-point(FTM) algorithm, figures out the mathematical model of the clock synchronization algorithm, and the mathematical model is analyzed. Through the analysis, it shows that the FlexRay clock synchronization algorithm has a strong fault-tolerance and applicability by mathematical formula.
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Computer Engineering. 2010, 36(14): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2010.14.086Aiming at the problem that static visual view of traditional argumentation information is unorganized and hard to recognize, this paper proposes argumentation information visualization framework and a solution based on interactive visualization techniques. An interactive visualization platform is carried out with Java, XML, JFreeChar and Prefuse, which is built upon node-link network layouts, allowing users’ interactive operation and supporting visual search and analysis. Operational result shows that the platform helps to understand argumentation information expediently, and it is extensible.
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Computer Engineering. 2010, 36(14): 241-242. https://doi.org/10.3969/j.issn.1000-3428.2010.14.087This paper proposes an forecast method for heavy rainfall cloud clusters based on FY2C satellite. Forecast storm position can be divided into three steps. A clustering technique is used to identify rainfall cloud. A combinatorial optimization method is utilized to track identified cloud. A linear extrapolation method is used to provide 30 min, 60 min and 90 min forecast. Experimental results show the efficiency of the proposed approach.
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Computer Engineering. 2010, 36(14): 243-245. https://doi.org/10.3969/j.issn.1000-3428.2010.14.088Aiming at the problem that hierarchical path planning algorithm always has to store the correspondence between roads of different hierarchies which makes the storage efficiency critical, this paper proposes an improved hierarchical path planning algorithm which is suitable for embedded system. This algorithm enhances computing speed by importing road class information into every road hierarchy, and dynamically switches searching hierarchy and class to reduce hierarchy number and the amount of data. Comparison experiment shows the improved algorithm has better performance than other three kinds of algorithms on the aspects of extended node number and path planning time, and it can satisfy the need of efficient path planning in embedded system.
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Computer Engineering. 2010, 36(14): 246-248. https://doi.org/10.3969/j.issn.1000-3428.2010.14.089In low to medium Signal to Noise Ratio(SNR), ESPRIT algorithm has low performance for noise affecting covariance matrix, and it makes ESPRIT algorithm have a performance gap to Cremer-Rao Lower Bound(CRLB). Aiming at this problem, this paper presents a noise suppression frequency estimation algorithm based on ESPRIT. It estimates the covariance matrix with spectral lines inside several sub-bands spectrum, signal subspace is spanned by the generalized eigenvectors of the improved covariance matrix and frequency is simultaneously resolved with the signal subspace. Experimental results show that this algorithm can be applied in multiple-frequency signals, it has full frequency range of , and the performance approaches CRLB.
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Computer Engineering. 2010, 36(14): 249-250. https://doi.org/10.3969/j.issn.1000-3428.2010.14.090An optimization method of AVS sub-pixel motion estimation is proposed. The method is devided into two parts, one is adaptive sub-pixel early termination algorithm and the other is an improved way of sub-pixel interpolation. The proposed method can highly reduce the interpolation complexity and search points for sub-pixel motion estimation, which is appropriate to be used on embedded system. The computational complexity can be reduced above 70% with the new method without losing the quality of the video.
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Computer Engineering. 2010, 36(14): 251-253. https://doi.org/10.3969/j.issn.1000-3428.2010.14.091Aiming at the hardware and software fault Chinese first micro-satellite may face, this paper introduces the dependable technology of On-Board Data Handling(OBDH) software. The on-board computer is designed as dual-computer system. When the switch happens between host and standby computer, the normal running of satellite can be kept by dual-computer communication. The main function of the satellite software is shown, and the OBDH software is projected. The paper illustrates the module design and the function of OBDH software, and the running mode of OBDH software is explained. The software reconstruction method after host computer failure is presented. The satellite fulfills the expectation aim, and the On-Board Computer(OBC) does good job as desire, so the design of OBDH software is safe and reliable.
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Computer Engineering. 2010, 36(14): 254-255. https://doi.org/10.3969/j.issn.1000-3428.2010.14.092This paper presents efficient components in the designs and implementations ation based on ColdFire MCF52233 U-ISP on studying its program mechanism deeply and integrated instances. The components contain flash page erase, flash page write and their initialization component. Practically, they can be used in all ColdFire MCUs in the same way.
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Computer Engineering. 2010, 36(14): 256-258. https://doi.org/10.3969/j.issn.1000-3428.2010.14.093A robust detection method of Matched Filtering(MF) is proposed to improve performance of conventional local optimization MF detection in impulsive noise environment. A nonlinear transform of observed signal is found by probability density function of impulsive noise distribution, and MF detection is used to transformed signal. The method is dull to characteristic exponent of impulsive noise, it can restrain effectively impulsive noise. Simulation results on MF detection of BPSK modulation show that the proposed method has better detection performance than conventional local optimization MF in impulsive noise and is robust to noise characteristic exponent.
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Computer Engineering. 2010, 36(14): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2010.14.094To estimate the power consumptions of each thread in the Simultaneous MultiThreading(SMT) processor, this paper presents a new thread-level power estimation scheme for SMT processor. It can count the power consumptions of each unit in the processor for the concurrent running threads. The scheme provides a functionality for power-aware thread scheduling and instruction fetching policies in a SMT processor. Experimental result shows that the sum of power consumptions of each thread is equal to the whole.
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Computer Engineering. 2010, 36(14): 262-263. https://doi.org/10.3969/j.issn.1000-3428.2010.14.095
As applications programs based on MapReduce model growing up, Hadoop’s performance depends on applications. From applications, this paper analyzes the limitations and shortcomings of Hadoop architecture and storage technology, and proposes a feasible and cost-effective solution to address the problem. It builds a series tests to convince the idea. The solution is multi-level parallel, both on job and I/O levels, which makes full use of disk and network bandwidth, reduces I/O bottlenecks and improves performance.
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Computer Engineering. 2010, 36(14): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2010.14.096This paper analyzes usage of Agent and social forces model in crowd evacuation. It gives the storage method of crowd and building object. The Agent model which can reflect the human behavior in evacuation is developed based on Agent technology, combined with kinetic model on crowd evacuation, improved best path arithmetic, psychological factor and the different character of architectures, and the crowd evacuation simulation is realized based on Agent technology with C++ language. The result of evacuation shows that the evacuation system can be authentic to simulate the crowd evacuation process.
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Computer Engineering. 2010, 36(14): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2010.14.097Aiming at the problem that the information isolated island is serious in the army equipment maintenance, this paper analyzes the effect in equipment maintenance of information integration, and puts forward the information integration realization method based on Service Data Objects(SDO), adopts equipment maintenance information integration based on SDO, and raises equipment maintenance efficiency. The practice indicates, by way of leading programming frame of SDO, it can reduce the coupling of data obtain business and data use business in the procedure of data integration.
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Computer Engineering. 2010, 36(14): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2010.14.098To solve the problem of resource sharing efficiency in P2P networks, this paper presents a self-adaptive sharing policy of computing resource sharing probability. The policy is used to decide whether a resource can be shared. It considers some key issues about resource sharing in P2P networks, such as limited store memory space, interrupted or redundant download process. A local computing method is used to compute the resource sharing probability in single agent. Experimental results show that the policy can effective decrease redundant download process numbers of sharing resources.
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Computer Engineering. 2010, 36(14): 273-274. https://doi.org/10.3969/j.issn.1000-3428.2010.14.099Analyzing the process of the U-Boot boot in the S3C2440A processor, according to the feature that S3C2440A processor supports the boot of Bootloader from NOR Flash and NAND Flash and the difference that U-Boot boots form NOR Flash and NAND Flash, a method of implementing U-Boot which supports Dual-Boot of NOR Flash and NAND Flash is proposed. The eventually realized source code is correctly compiled in the ARM-Linux cross-compiler and runs stably in development board based on S3C2440A processor.
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Computer Engineering. 2010, 36(14): 275-277. https://doi.org/10.3969/j.issn.1000-3428.2010.14.100Processor performance depends on its configuration of various internal resources——usually the more resources, the more favorable performance. This paper finds that a reasonable resource configuration is more important. Rather than boosting the performance, overwhelming or improper configuration are more likely to have a negative impact. It analyzes the potential interference among various resources and their influences on the overall performance involving the phenomenon, the processes and the causes.
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Computer Engineering. 2010, 36(14): 278-280. https://doi.org/10.3969/j.issn.1000-3428.2010.14.101For the complexity of the transport business systems and diversity of traffic information, in order to achieve consistency and effectiveness of information integration, a message bus-based traffic information integration model is proposed. The model uses a channel mechanism to the registration and management information integrated services. Message integration agent can be deployed in the channels for further separation and fusion, in order to achieve the fusion of heterogeneous sources of information, and model the urban traffic management and information services platform for a simpler mode of data sharing has better information analysis capabilities and the efficiency of event handling.
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Computer Engineering. 2010, 36(14): 281-284. https://doi.org/10.3969/j.issn.1000-3428.2010.14.102Aiming at the factors of resource constraints that exist in the process of course schedule, this paper proposes an algorithm combining Genetic Algorithm(GA) and constraint satisfaction algorithm to solve course schedule problem. Course schedule tasks are sorted with constraint satisfaction algorithm, and a single course schedule task’s timetable is allocated and optimized with GA. In this algorithm, the result of single course schedule task is global optimal. Experimental results show that this method is feasible to improve the performance and the efficiency.
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Computer Engineering. 2010, 36(14): 285-287. https://doi.org/10.3969/j.issn.1000-3428.2010.14.103This paper introduces the shortage of mobile E-commerce that is based on current WAP technology, and proposes a SIM browser technology to provide E-commerce transactions models that are more diverse, and more secure. In the framework of 3GPP protocol, this paper proposes specific system structure, data transfer mechanism and encryption mechanism of the scheme. The proposing of this scheme makes common users more simply enjoy a variety of Internet service.
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Computer Engineering. 2010, 36(14): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2010.14.104This paper analyzes insufficiency of present Linux operating system. Based on the structure of the Real-time Application Interface (RTAI) and Complete Fair Scheduler(CFS), a novel kernel process scheduler tactic is proposed and compiled into the operating system. The system performance test indicates that whether the system is busy or not, the improved system outperforms the previous ones, particularly, the more complicated the progress is, the more evident the performance improvement is.
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Computer Engineering. 2010, 36(14): 291-292. https://doi.org/10.3969/j.issn.1000-3428.2010.14.105In order to construct a data link simulation platform with good scalability and flexibility, this paper presents a forwarding data link simulation platform architecture based on High Level Architecture(HLA). It separates simulation of data link application layer from transport layer. With the purpose of verifying the feasibility and rationality of this architecture, it quantitatively analyzes the architecture influences on execution of time stamp interactions and received order interactions. Simulation platform prototype shows that this architecture has superior application adaptability, higher reusability of core simulation modules and good system scalability.
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
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Executive Chief Editor:
Hu Bing
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CN: 31-1289/TP
ISSN: 1000-3428