05 March 2011, Volume 37 Issue 5
-
Select all|
-
Computer Engineering. 2011, 37(5): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2011.05.001This paper establishes a simplified Beijing urban multi-ring road system model, applies the shortest path algorithm, simulates the shortest path and least time path of vehicle from the start point to the end point in the condition of ring road and no ring road. With generating randomly a lot of start points and end points, it analyzes time decrease and distance augmentation of vehicle which passes the ring road to research the influence of ring road to traffic and environment. Experimental result shows that ring road increases people’s travel cost and environment pressure, and it has great effects for Beijing’s environment.
-
Computer Engineering. 2011, 37(5): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2011.05.002This paper studies a multi-objective location problem of transshipment nodes in joint allocation and transportation of mass relief materials. Transportation costs, operating variable costs of transshipment nodes and travel time are considered, and a nonlinear multi-objective mixed integer programming model for the transshipment nodes location of relief materials is proposed. To solve the model effectively, a matrix-based encoding GA is proposed, in which the cost matrix of the optimization-oriented benchmarking information is used to enhance local search ability of genetic mutation operator and improve global convergence speed. A numerical example verifies the effectiveness of the model and algorithm.
-
Computer Engineering. 2011, 37(5): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2011.05.003This paper researches how to use RAISE Specification Language(RSL) to describe operators of Temporal Logic(TL), such as always operator, sometimes operator, until operator and complex operators of TL, and presents the method of formal description with RSL based on TL model. Formal description of AB(Alternating Bit) protocol with RSL based on TL model is given as an example. The result proves that the description model helps realizing automatic implementation of protocols verification and testing.
-
Computer Engineering. 2011, 37(5): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2011.05.004Aiming at measurement of parallel computing system performance, based on productivity model, this paper proposes a productivity parallel speedup model, which integrates reliability, communication, parallel control and cost in the view of system scalability. The key factors affect parallel productivity including the factors of fault tolerant overhead, communication overhead, parallel control overhead and cost overhead are analyzed and tested to verify the validity of the model.
-
Computer Engineering. 2011, 37(5): 13-15. https://doi.org/10.3969/j.issn.1000-3428.2011.05.005It is necessary to provide the number of clusters before it is used in the traditional Fuzzy c-Means clustering algorithm(FCM), but error number of clusters will make error result. Aiming at this proplem, this paper presents a novel clustering algorithm based on artificial immune cell model. With an idea of dual iteration of a combination of population size iteration and fuzzy clustering iteration, this algorithm inducts auto-formation of clusters number by use of the population size iteration and solves the problem of inputting the number of clusters in advance. The fuzzy clustering iteration which is introduced in each iteration of population size, adds clonal selection as well as antibody immune suppression operation. Theoretical analysis and simulation results show that the algorithm can get correct number of clusters, and get better clustering effect.
-
Computer Engineering. 2011, 37(5): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2011.05.006This paper adopts empirical research method, with Wiki network baidu-baike for research object, 184 470 topics are collected and mapped into complex network. By calculating the node degree distribution, the average path length and the clustering coefficient of the network, it is got that the knowledge cooperation network with knowledge topic has the features of scale free and small world. In comparison of the existing evolving mode for complex network with the result demonstrated by empirical research on World Wide Web, Internet and Science collaboration graph, the evolving rule is initially revealed for the knowledge cooperation network.
-
Computer Engineering. 2011, 37(5): 19-21,24. https://doi.org/10.3969/j.issn.1000-3428.2011.05.007The mathematical model of minimizing the average power of base station under delay constraint is proposed for multi-user system in CDMA downlink. The problem is formulated as an unconstrained Markov Decision Process(MDP) and solved by dynamic programming. And the proposition that two users power-delay surface is a convex surface is proved, which indicates that in CDMA downlink multi-user system, increasing the delay can save power and average delay and power still has a convex function. Simulation result shows the relationship is established correctly.
-
Computer Engineering. 2011, 37(5): 22-24. https://doi.org/10.3969/j.issn.1000-3428.2011.05.008A novel method for positive area extraction is proposed according to the characteristics of immunohisechemical color images for mouse liver. Images are transformed from RGB to HSI. It is found that the positive pixels through analyzing the sample pixels in three arbitrary images. Median filtering algorithm is used to remove the wrong areas. Experimental results show that 82.9% results are in accordance with the estimation of physicians. In comparison with other methods, this algorithm is more appropriate and effective.
-
Computer Engineering. 2011, 37(5): 25-28,32. https://doi.org/10.3969/j.issn.1000-3428.2011.05.009Aiming at the shortages of complex computing and low efficiency in traditional circle mark location method, this paper combines the quickness of point Hough transformation and the precision of sub-pixel, presents circle sub-pixel detection algorithm based on point Hough transformation and Legendre moments. It uses the algorithm to detect round location mark in PCB vision detection. Experimental results show that the positioning accuracy amounts to 0.056 pixels, it has the characteristics of anti-noise, accuracy, rapidity and robustness, and it can satisfy the requirement of high precision and real-time in PCB visual detection.
-
Computer Engineering. 2011, 37(5): 29-32. https://doi.org/10.3969/j.issn.1000-3428.2011.05.010Based on dynamic cognition of network topology, this paper proposes a model to evaluate networks invulnerability capability named network invulnerability ration EFF(G), which comprehensively considers connectivity of network topology, the extent of destroy after networks suffered and the inner structure of connective branches in topology, and presents a strategy management mechanism named Cognitive Topology Invulnerability Reliability Management Mechanism(CTIRMM). It aims at distribution of Ad Hoc networks and it can enhance Ad Hoc network reliability in effect. Example analysis results show that EFF(G) can effectively evaluate invulnerability and reliability of Ad Hoc networks.
-
Computer Engineering. 2011, 37(5): 33-34,37. https://doi.org/10.3969/j.issn.1000-3428.2011.05.011Aiming at the number of joint paths and disjoint path can not accurately reflect network system reliability, in the condition of node failure, this paper builds weighted network end-to-end reliability model based on disjoint path, and presents a numerical solving algorithm. Example analysis result shows that this model can exactly compute the lower bound and the upper bound of two-terminal reliability, and provide the quantitative analysis of network reliability in the condition of network components failure rate of continuous change and network components load rate of weight.
-
Computer Engineering. 2011, 37(5): 35-37. https://doi.org/10.3969/j.issn.1000-3428.2011.05.012Aiming at the cooperation spectrum detection in Wireless Sensor Network(WSN), this paper presents a distributed spectrum detection based on sequential Markov chain. It assumes the detection of the single node is a Markov process, and the result value of local sequence detection is obtained by the Sequential Probability Ratio Test(SPRT). After the measurements result of each node’s own is sent to the data fusion center, the final results can be determined in line with the threshold. Matlab simulation validates the sequential detection performance.
-
Computer Engineering. 2011, 37(5): 38-40. https://doi.org/10.3969/j.issn.1000-3428.2011.05.013This paper proposes a distributed storage scheme based on Information Dispersal Algorithm(IDA). This scheme can be deployed on top of current grid middleware, it divides a data file into blocks and distributes them across many target storage nodes. Theoretical analysis and experimental results show that the distributed storage scheme has better data reliability and data access performance than existing data replication methods.
-
Computer Engineering. 2011, 37(5): 41-43. https://doi.org/10.3969/j.issn.1000-3428.2011.05.014Existing database system can not support to store a whole folder into a database and provide random access to any file in it. Aiming at this problem, this paper puts forward a method to store a folder as a whole and access its file randomly in a database based on the integration of Binary Large Object(BLOB), stream and serialization technology. The folder is packed up, resulting in a file stream and a directory structure object. The directory structure object is serialized to a directory structure stream. The file stream and directory structure stream are saved as BLOB data in a database respectively. When reading from the database, it first reads the directory structure BLOB data as a stream, and deserializes it to the directory structure object. With the information in the directory structure object, it can choose which file to access and ascertain its location and size in the folder’s file BLOB data. It reads the corresponding data section out of the database and realize the random access of a file.
-
Computer Engineering. 2011, 37(5): 44-46,49. https://doi.org/10.3969/j.issn.1000-3428.2011.05.015This paper shows the feature vectors that represent the users of network forum, which are associated with seven feature values. In this paper, a users clustering algorithm is designed on the basis of EM algorithm. The algorithm is used to identify the subclass that matches opinion leaders best from the data set extracted from real posts of a forum. An example is given to compare this algorithm with other algorithms, which verifies the correctness of this algorithm.
-
Computer Engineering. 2011, 37(5): 47-49. https://doi.org/10.3969/j.issn.1000-3428.2011.05.016The existing encoding scheme such as prefix-based and region-based encoding can not effectively support the update computation. Aiming at this problem, this paper proposes a new prefix-based encoding scheme named TDE. The scheme maps any real number to 2-tuple, then no second encoding while inserting a new node in XML document because there are unlimited real numbers between arbitrary nodes, the TDE scheme comes into possession of less storage space than other schemes after compression. Experimental results show that TDE can effectively support the update computation of XML document.
-
Computer Engineering. 2011, 37(5): 50-52. https://doi.org/10.3969/j.issn.1000-3428.2011.05.017The traditional techniques for indirect jump analysis are limited to special platform or compiler pattern. To deal with the problem, this paper proposes an indirect jump analysis method based on Critical Semantic Subtree(CSS), which is extracted from the semantic tree created by machine instruction semantic specification. Since it focuses on the semantic character and makes jump destination to be computed automatically, this method can recover jump target addresses in a machine and compiler-independent way. Experimental results prove that the method has good generality.
-
Computer Engineering. 2011, 37(5): 53-55. https://doi.org/10.3969/j.issn.1000-3428.2011.05.018This paper presents a linear time algorithm to find the Steiner tree in Halin network. The algorithm proposes the concept of pseudo-fan. It enumerates all the possible conditions of Steiner tree in a fan during the expansion from pseudo-fan to fan and recursively shrinks fan structure. Steiner tree is found by reverting all the fans in the end. The proof of correctness and the analysis of the complexity of the algorithm are given. An example is presented. The algorithm has great value to the multicast routing in Halin network.
-
Computer Engineering. 2011, 37(5): 56-58. https://doi.org/10.3969/j.issn.1000-3428.2011.05.019The paper studies the knowledge structure of conversion between the production analysis and relational mode. It includes the standard description of the meta-concept, the fact of engineering, design rules, and production activities. The representation method of knowledge frame is used to represent production concept and fact, and the service is used to represent the normal scheme of engineering. The domain ontology describes the basic concepts and relations among them, and defines the mapping relationship between logical concept and relational mode on the basis of above discussion. Considering the fact which considers production information as middle knowledge, it achieves conversion between the production fact and relational mode. It designs the knowledge structure for oilfield development.
-
Computer Engineering. 2011, 37(5): 59-61,64. https://doi.org/10.3969/j.issn.1000-3428.2011.05.020This paper presents a model of two-dimensional Mix Conditional Random Fields(MCRF) which are used for the extraction of Web records. It overcomes the shortcomings of linear-chain conditional random that it can not take full advantage of dependencies between the various elements of Web entities. Meanwhile, it solves the problem that training CRF model often requires large number of hand-labeling sample data. In the experiment, it tries to extract 742 data records from Dangdang online, and compared with other models under the same conditions. Experimental results show a more superior performance during extracting TDS.
-
Computer Engineering. 2011, 37(5): 62-64. https://doi.org/10.3969/j.issn.1000-3428.2011.05.021Based on the base/deputy version technology, this paper presents a heterogeneous distributed fault tolerance schedule model and HDL algorithm is given. The algorithm overcomes instability problems of the previous algorithm to balance the load before and after failure, and a certain extent achieves a balanced controllability, while the covariance-based load balance approaches are given in simulation experiment. Experimental results show the load balance of the algorithm is stabile before and after a failure occurs.
-
Computer Engineering. 2011, 37(5): 65-67,70. https://doi.org/10.3969/j.issn.1000-3428.2011.05.022This paper designs an improved algorithm named BF-Apriori based on Binary and item support distribution. The algorithm analyses the probability distribution of the items, sorts them in descending order of the probability, and applies dimensions coding to reduce the cost of the database transactions to read and store overhead. While the slice operation and effective pruning scheme are used to reduce the time complexity of rule mining computing. Experimental results show BF-Apriori algorithm reduces about 50% of the storage and more than 400% of the execution time, it can improve the storage efficiency and computational speed in data mining.
-
Computer Engineering. 2011, 37(5): 68-70. https://doi.org/10.3969/j.issn.1000-3428.2011.05.023In order to resolve the problem of assigning project team staffs reasonably on the active above the Team Software Process(TSP), TSP model with regard to the objectives and activity-oriented is described and an optimization method based on Genetic Algorithm(GA) is proposed. With analyzing the core idea of TSP, the structure and the formal description of the model are given. The steps for building model are introduced. Optimization experiment results show that the algorithm’s performance is good, while, the practicable staff allocation scheme with a better efficiency value is obtained and the practicality of model is improved.
-
Computer Engineering. 2011, 37(5): 71-73,76. https://doi.org/10.3969/j.issn.1000-3428.2011.05.024Focused on the existing file system in the fault-tolerance and reliability are much lower than the database system, this paper uses the principle of data multiple versions technology in database system to achieve quickly flashback and non-blocking read. By improving the meta-data structure of file system and the combination of copy-on-write techniques, this paper solves the problem of existing file system lack of fault tolerance and enhances the read performance of file system. MVFS is made by the method. Experimental results on MVFS show that the method applied to generate the file system posses excellent read performance, fault tolerance and reliability
-
Computer Engineering. 2011, 37(5): 74-76. https://doi.org/10.3969/j.issn.1000-3428.2011.05.025Mining data streams require algorithms that make fast response, make light demands on memory resources and are easily to adapt to concept drift. This paper proposes a new algorithm for data streaming mining with concept drift called AHBag, which is based on Hoeffding tree online Bagging ensemble. The algorithm tests data within an adaptive window using the statistical theory for capturing the concept drift. According to the test results to update Hoeffding tree or rebuild a new Hoeffding trees. Experimental results show that the algorithm has a highly accuracy in dealing with data streams with concept drift.
-
Computer Engineering. 2011, 37(5): 77-79,82. https://doi.org/10.3969/j.issn.1000-3428.2011.05.026This paper proposes a method for the data source discovery using the search engine. In order to submit high quality key words to the search engine, the paper introduces the ontology to the initial word construction process, classifies all the words according to their frequency in the current domain, and reclassifies these words in accordance with the element quantity of the returned collection, ensures that the key word contributes greatly to the discovery of the data source query interface. Test results in different domains show that the approach proposed can discover a large amount of query interfaces, and its validty is verified.
-
Computer Engineering. 2011, 37(5): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2011.05.027The problem of k Obstructed Globally Different Optimal Sequenced Route(kOGDOSR) query is proposed. The approximate algorithm for resolving this query problem is put forward based on visibility graph. The introduction of effect set and obstructed angle point reduces the number of obstacles used in the configuration of visibility graph. It decreases the number of inner obstructed route calculations through analyzing the relationship between the line segment from query point to data point and the vertices and arcs of the visibility graph. The algorithm is optimized completely through the two aspects described above. Experimental results indicate that the algorithm presented has a better performance.
-
Computer Engineering. 2011, 37(5): 83-85. https://doi.org/10.3969/j.issn.1000-3428.2011.05.028Recurrent Least Squares Support Vector Machines(RLSSVM) is proposed to construct the failure model of software reliability and train it recurrently by using failure data set to improve its learning ability. The recurrent algorithm is used in model to reflect dynamically the change of software reliability so the model can predict accurately the software failure. Simulated Annealing(SA) algorithm is used to optimize the parameters of RLSSVM to construct more optimal failure model. After comparing with the models of NHPP category, the model based on RLSSVM and SA algorithm has better ability of fitting and prediction.
-
Computer Engineering. 2011, 37(5): 86-87,90. https://doi.org/10.3969/j.issn.1000-3428.2011.05.029A critical problem in data grid is how to give general access service for distributed and heteromerous data source. In this paper a programming model for data access is addressed based on open source project Tuscany Das, and functions in the model are provided for clients. Those functions include CRUD operations, calling stored procedure and recordset paging. A GIS application on data grid platform for China earthquake disaster alleviation grid testbed is completed using this model and its functions.
-
Computer Engineering. 2011, 37(5): 88-90. https://doi.org/10.3969/j.issn.1000-3428.2011.05.030This paper provides a handoff decision algorithm based on admission control of target cell in the E-UTRAN architecture. In order to predict the admission control of target cell, it uses the X2 interface between eNBs to exchange the load information load network, resource information, and services rate of network. It constructs the Manhattan model. Simulation results indicate that the algorithm has higher successful handoff rate and smaller delay of handoff. It can switch the user terminal to the cell with lighter load, to make sure balancing the neighboring load and improving utilization of wireless resources.
-
Computer Engineering. 2011, 37(5): 91-93. https://doi.org/10.3969/j.issn.1000-3428.2011.05.031By the impact of Doppler frequency offset and unstable receiver oscillator, the received PN signal exists frequency offset and symbol synchronization. This paper presents PN sequence coherent acquisition algorithm with joint time-frequency domain correction. The joint correction of carrier frequency and symbol synchronization are based on the cyclostationary property of received PN signal, so that the corrected PN signal and local PN sequence have approximate coherency. And a longer correlation length coherent detection is achieved by the correlation characteristic function to complete the PN sequence acquisition. Simulation results show that, the PN sequence coherency acquisition has a higher detection probability at low SNR signal and large Doppler frequency offset.
-
Computer Engineering. 2011, 37(5): 94-96. https://doi.org/10.3969/j.issn.1000-3428.2011.05.032The frequency features of the optical transient signal are analyzed and the spectrum is estimated. The result is that the signal of spatial transient optical is random signal. The analysis of the covariation-spectrum estimations based on FLOM, finding that this method is not applicable when α<1. A method of estimation of Fraction Low Order Covariation(FLOC) is proposed. The comparison of emulator results of two spectrum estimations show the method presents a good capability and it can be widely applied to α-stable distribution. Through the comparison, concluding that the optical transient signal is α-stable distribution.
-
Computer Engineering. 2011, 37(5): 97-99,102. https://doi.org/10.3969/j.issn.1000-3428.2011.05.033An evaluation method of command information system invulnerability based on service capability in Network-Centric Warfare(NCW) is proposed. The service mechanism of command information system in NCW is analyzed, and the concept of service functional chain is given for system service capability evaluation. The evaluations of system invulnerability and node significance are derived from the influences of both network topology and service relations between nodes. An instance is designed, and the method’s feasibility is verified by the simulation results.
-
Computer Engineering. 2011, 37(5): 100-102. https://doi.org/10.3969/j.issn.1000-3428.2011.05.034Based on complicated Internet topology, an improved Cluster Overlay model and a topology-aware Relay lookup scheme in application-layer routing system are proposed. The improved model can modify the clustering adaptively according to the complicated topology, thus making the Cluster Overlay more similar to Internet topology, and the Relay lookup scheme can utilize complicated Internet topology to further improve path quality. Experimental results show that the improved Cluster Overlay model and the Relay lookup scheme have excellent performance.
-
Computer Engineering. 2011, 37(5): 103-105. https://doi.org/10.3969/j.issn.1000-3428.2011.05.035This paper proposes a simple and efficient distributed channel allocation algorithm. It uses comprehensive dynamic network information to make better channel assignment decision. A back-off mechanism is designed to reduce the collision overhead during the algorithm running. The extensive NS2 simulation result shows that, compared with the traditional distributed ones, the new algorithm is converged quickly, reliable and stable, so effectively increases the network overall throughout.
-
Computer Engineering. 2011, 37(5): 106-108. https://doi.org/10.3969/j.issn.1000-3428.2011.05.036As the existence of nodes’ highly dynamic character and nodes’ non-reachability in large-scale network, direct measurement of the node-delay is sometimes simply impossible. This paper proposes a method of Non-negative Matrix Factorization Prediction(NMFP), constructs a characteristic matrix for the RTT between common node and benchmark node. Utilizing method of coordinate calculation in European space, according to the non-negative characteristic of distance matrix, it ensures the matrix non-destructively broken down into the product of the base vector and weight vector. This approach reduces the dimension of distance calculation, speeds up the convergence of prediction, the accuracy of the prediction in line with the trend forecast prediction error distribution model.
-
Computer Engineering. 2011, 37(5): 109-111. https://doi.org/10.3969/j.issn.1000-3428.2011.05.037Based on the hop count of the destination node and the base path, the paper proposes a routing protocol HAODV to improve AODV. HAODV uses the hop count of the destination node to fix the routing path quickly and efficiently whenever the link breaks because the nodes can not move a lot in a period time, and uses the hop count of the base path to reduce the broadcast storm effectively. Simulation results show HAODV is higher than the AODV in packet delivery ratio, less the average delay and less path hop count.
-
Computer Engineering. 2011, 37(5): 112-114,117. https://doi.org/10.3969/j.issn.1000-3428.2011.05.038Based on research of small-world network and Cayley graph, it adopts the algebra and graph theory method of Cayley graph, a model of small-world network with high symmetry is proposed. Some properties of small-world such as clustering coefficient and characteristic path length are analyzed. A routing algorithm is developed. Results of analysis and simulation testify this model provides high local clustering and low network diameter, possesses the property of small-world.
-
Computer Engineering. 2011, 37(5): 115-117. https://doi.org/10.3969/j.issn.1000-3428.2011.05.039Considering the difficulty in precise measurement of time synchronization algorithm of wireless sensor networks, this paper proposes a measurement method with high precision and low cost by utilizing the capability of the “self interrupt”, which is realized in many microcontrollers. The measurement method is realized on GAINS testbed. To verify its validity, the synchronization error of TPSN is measured on the testbed. Compared with the measurement method with logic analyzer, better precision and lower price are simultaneously gotten.
-
Computer Engineering. 2011, 37(5): 118-120,123. https://doi.org/10.3969/j.issn.1000-3428.2011.05.040This paper proposes an improved Directional Transmission and Reception Algorithm(DTRA) named SDTRA protocol based on slot schedule. In the process of neighbor discovery stage, the protocol decreases the collision through sending time random delay. In the process of slot schedule stage, it adopts greedy edge coloring algorithm to control the time the node can use. The protocol can assure the QoS support through synchronous slot schedule algorithm. Simulation results show that the improved DTRA protocol is much better than DTRA protocol in neighbor discovery, time utility and throughput.
-
Computer Engineering. 2011, 37(5): 121-123. https://doi.org/10.3969/j.issn.1000-3428.2011.05.041This paper proposes a multi-node removed dynamic algorithm based on routing Shortest Path Tree(SPT). The algorithm establishes an SPT update queue to preserve all the descendent nodes of removed nodes; deletes nodes that needed to be removed and their descendent nodes from original SPT; selects a node with the shortest distance to the source node from the queue to carry on the updating. In order to reduce the updated frequency, the node can not be inserted into the queue again after updating. Experimental result shows that this algorithm can largely reduce the updated redundancy.
-
Computer Engineering. 2011, 37(5): 124-126,130. https://doi.org/10.3969/j.issn.1000-3428.2011.05.042A virtual backbone network is used to take on forwarding data in Wireless Sensor Network(WSN), therefore the energy of these backbone nodes are run out too quickly, which causes the network not connected. To address this issue, this paper proposes a Multiple Virtual Backbone Networks Rotation(MVBNR) algorithm based on connected domatic partition. The algorithm uses the connected domatic partition of graph theory to construct as many disjoint virtual backbone networks as possible, let them periodically take turns forwarding data, so as to achieve the purpose of network load balancing and network lifetime extending. Theoretical analysis proves that the MVBNR algorithm constructs a connected domatic partition whose size is at least [(δ+1)/(β×(c+1))]－f and the algorithm’s message complexity and time complexity are O(nδ). Simulation result shows that the average number of backbone nodes, the number of backbone networks and the network lifetime produced by the MVBNR algorithm are better than those produced by the IDKDP algorithm.
-
Computer Engineering. 2011, 37(5): 127-130. https://doi.org/10.3969/j.issn.1000-3428.2011.05.043The worst case for real-time transmission on Fibre Channel-Arbitrated Loop(FC-AL) is complemented when considering the priorities of messages. Two conditions to guarantee the deadlines of each message in the message set are re-defined. The concept of the fairness load rate under the worst case is presented so that the above two conditions can be concluded as: the fairness load rate of each message under the worst case should not be greater than 1. This conclusion exposes the essential relationship between the real-time transmission and load rate. Thinking about the increasing cost of protocols and the delay of physical layer due to the segmentation of messages, a dedicated algorithm of bandwidth allocation based on the principle to minimize the total load rate of the network is given. A synthetic message set is studied to prove the validity of this method.
-
Computer Engineering. 2011, 37(5): 131-133. https://doi.org/10.3969/j.issn.1000-3428.2011.05.044Based on string space, this paper proposes an automatic verification algorithm for security protocol named Intelligent Validation for Authentication Protocol(IVAP). For the protocol with flaw, it generates the improved secure protocol automatically by searching backward the tree of the primary strand aiming at the unsafe attributes, and validates it until the improved protocol is safe. Experimental result proves the effectiveness of the algorithm. Compared with AAAP algorithm, IVAP algorithm is more efficient.
-
Computer Engineering. 2011, 37(5): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2011.05.045In order to improve the performance of Intrusion Detection System(IDS), this paper proposes a feature extraction method based on knowledge reduction. Rough set theory is used to do the formal description for IDS. Knowledge reduction is used to extract attribute features. Information loss and information gain are individually used to control the discrete procedure of continuous value attributes and the reduction of attribute features. Experimental result justifies that the method can eliminate the redundant information and noise of initial data effectively.
-
Computer Engineering. 2011, 37(5): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2011.05.046Based on dividing blocks Curvelet transform, according to the change of the coefficients in detail scale layers keep energy conservation in the ridge domain, the secret message can be inserted through blocks energy quantization, it is block quantification embeds secret information. This paper presents an information hiding algorithm which is blind to extraction and robust to common attacks, especially to JPEG. Experimental results show that it can improve the secret message capacity, and suit to covert commutation against JPEG attack, which inserts messages in detail1 and detail2 scale layers. It can obtain more strong robustness to semi-fragile watermark which inserts messages only in detail1 scale layers.
-
Computer Engineering. 2011, 37(5): 140-142. https://doi.org/10.3969/j.issn.1000-3428.2011.05.047Aiming at the problems that multicast key management scheme exists forward confidentiality, backward confidentiality and conspiracy cracked, this paper presents an improved multicast key management scheme. It includes multicast authentication, secure multicast forwarding tree management, key distribution when users are initialized and periodical key updating. It reduces the complexity of the key updating problem when members leave the group by two-layer control and guarantee the efficiency and security of key management. Experimental result shows that this scheme performs better on computation cost and communication cost, and it has acceptable storage cost.
-
Computer Engineering. 2011, 37(5): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2011.05.048This paper designs a trusted anonymous authentication protocol based on trusted computing technology. The protocol can achieve the two-way authentication between users and server. The server can achieve the trusted assessment of user trusted platform, the trusted user is awarded the authorization certificate from server, and the certificate is issued once for repeated usage. This method improves the efficiency of server and reduces the load measurement of trusted platform module. Verification result under Universally Composable(UC) security model shows that this protocol has safety and trustworthy, and it has the characteristics of efficiency, controllability, cross-domain.
-
Computer Engineering. 2011, 37(5): 146-148. https://doi.org/10.3969/j.issn.1000-3428.2011.05.049The time of modular exponentiation is not constant when RSA cryptographic algorithm is executed, so carefully measuring the information about different time to decrypt can deduce the secret key. This paper researches the implementation of RSA public-key cryptographic algorithm and the principle of the timing attack, analyzes the process of RSA decryption, discovers the vulnerabilities of RSA on timing attack, presents the algorithm of differential timing attack on RSA using from left to right “square-multiply” modular exponentiation, and discusses how to defense timing attack on RSA.
-
Computer Engineering. 2011, 37(5): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2011.05.050Universal designated multi-verifiers signature scheme allows a signature holder to designate the signature to a set of designated verifiers. Sequential multi-signature schemes can satisfy physical demanding which needs many signers to carry on the signature by the strict order. According to the above characteristics, this paper proposes an identity-based universal designated multi-verifiers sequential multi-signature scheme. The short signature is used to construct this new sequential multi-signature and the scheme’s security proof is provided under the random oracle model. Analysis results show that the scheme is extremely efficient and it can resist the adaptively select of message and identity attack.
-
Computer Engineering. 2011, 37(5): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2011.05.051By combining the System On a Programmable Chip(SOPC) and the IPSec technology, this paper designs a virtual private security gateway based on reconfigurable cipher processing module. A-two CPU architecture is adopted, one CPU is used as main processor and the other is used as IPSec coprocessor. The main processor mainly finishes the following task, which initializing configuration of the chip, controlling the system, management and the preprocessing of the data. The IPSec coprocessor mainly performs the IPSec processing function. The reconfigurable cipher processing module is used to accelerate the encryption and the decryption, so the cipher algorithm is processed faster than before and the security of the IPSec protocol is better at this gateway. Experimental result shows that this gateway has higher processing rate and can satisfy the security demand of small network.
-
Computer Engineering. 2011, 37(5): 158-160. https://doi.org/10.3969/j.issn.1000-3428.2011.05.053This paper researches SQL injection attack and grammatical features, constructs the regular expression for these attacks, and designs a SQL injection attack filter module inside Web server based on the filter rules using regular expression. It makes Http request realize injection attack detection before be submitted to the system module. Test results show that compared with filtering based on pure key-words, the filtering based on regular expression has higher recognition rate and lower false positive rate. Web server loaded with filtering module can defense SQL injection attacks effectively, and service delay is smaller.
-
Computer Engineering. 2011, 37(5): 161-163,166. https://doi.org/10.3969/j.issn.1000-3428.2011.05.054This paper starts from an introduction of Mandatory Access Control(MAC) and presents some technologies which implement it in Linux mainline kernel, including SELinux and SMACK, and gives an example in detail of how to define SMACK rule set to address the requirements of constructing sandbox for third-party applications in Linux based mobile phone. Result of test indicates that running smack has fewer memory consumption and more efficient CPU performance comparing with SELinux, and SMACK is more suitable for embedded system. .
-
Computer Engineering. 2011, 37(5): 164-166. https://doi.org/10.3969/j.issn.1000-3428.2011.05.055Evidence theory relies on expert knowledge to provide evidences and require evidences independent, which makes it hard to be applied. To solve the problem, this paper proposes a hybrid approach based on rough set theory and evidence theory. In order to obtain Basic Probability Assignment(BPA) for all evidences, a method of getting evidences and objective BPA based on rough set theory is presented to decrease the combination computation and improve the combination efficiency. Conflict evidences are reduced by applying the attribute simplification algorithm of rough set theory to eliminate redundant evidences. A model for network intrusion detection based on rough set theory and evidence theory is provided to show that the hybrid model has high detection precision and low false positive detection rate.
-
Computer Engineering. 2011, 37(5): 167-168,171. https://doi.org/10.3969/j.issn.1000-3428.2011.05.056Data Encryption Standard(DES) is a realization of Feistel algorithm, but the length of its key is too short. It can not meet the needs of network security now. Aiming at this problem, this paper proposes a simple method of key extension for the DES. This method extends DES key from 56 bit to 112 bit, and proves its validity by experimental result.
-
Computer Engineering. 2011, 37(5): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2011.05.057Using information system security assurance evaluation framework GB/T20274 as evaluation standard, it usually uses Dempster method to combine evidence results according to D-S evidential theory, but this method gets wrong result when the evidences have high conflicts. This paper puts forward an evidence combination rule based on fuzzy distance to solve the problem, and compares it with other evidence combination methods like Murphy method and the combination method based on the distances between evidences. Experimental result shows that the method can reduce the conflicts, and it has higher speed of constringency and lower complexity.
-
Computer Engineering. 2011, 37(5): 172-174,178. https://doi.org/10.3969/j.issn.1000-3428.2011.05.058The main form of network attack is multi-step attack. The current security equipments can only detect but not forecast. For this issue, this paper presents an approach based on attack utility to recognize the attacker’s finally intention and forecast the next possible attack. It describes a multi-attack by the attack intent, and establishes the multi-attack logic diagram based on the attack intention. During the procedure of the attack forecast, attack utility is used to represent the attackers benefit for each attack step. The attack utility is an important reference for the multi-step attack forecast. Experimental results prove the validity of the algorithm.
-
Computer Engineering. 2011, 37(5): 175-178. https://doi.org/10.3969/j.issn.1000-3428.2011.05.059Aiming at the image tamper restore problem, this paper proposes a self-fragile authentication watermark embedding method. The method extracts the image sub-block size of 2×2 gray mean by chaotic encryption mapping to determine the embedded bit-plane and the automor- phism mapping information as a watermark, embeds it into the original image for all pixels in the two least significant bit. This method does not need any original image and additional information relating to a watermark, it can implement the exact detection and location of small image tampering and restore it to the image sub-block. Experiment and analysis show that the method of arbitrary tampering with extremely sensitive to restore image quality and better safety performance.
-
Computer Engineering. 2011, 37(5): 179-180,183. https://doi.org/10.3969/j.issn.1000-3428.2011.05.060This paper proposes a proxy signature scheme with fail-stop property. Its computational security is based on discrete logarithm problem. Fail-stop property makes the signature forger with unbounded computational resources, so that he can indeed forge a valid signature, but honest signer can prove with overwhelming probability that the signature is a fake one. So that the original signer can take additional actions in time.
-
Computer Engineering. 2011, 37(5): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2011.05.061Aiming at the deceive attack of ARP protocol in campus network, this paper proposes an active protection scheme. It analyses method and principle of ARP attack and realizes the location of attack with ID authentication system and active protection force to isolate users. Application result shows that the scheme can be against most ARP attack, reduce the difficulty of network management and decrease the level of network running.
-
Computer Engineering. 2011, 37(5): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2011.05.062Based on the analysis of the limitation of traditional sample reduction method, a new distance model is proposed, and the measurement method of intra-class distance and inter-class distance of samples is given. By using the new distance mode, the methods of noise identification and importance evaluation are described, and the algorithm of training sample reduction is proposed. The algorithm removes noise samples. According to the similarity of sample, inter-class distance of sample and the number of deleted samples around, the algorithm removes lesser important training samples from the original sample space directly. Simulation results show that the distance model has lesser contingency and better anti-noise ability, and the reduction performance of the algorithm is better than traditional methods.
-
Computer Engineering. 2011, 37(5): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2011.05.063Two one-class classification models, one-class support vector machine and support vector data description, which are based on support vector machine and one-class classification are introduced. The internal relationship and parameters optimization of the two models are also analysed, and the exists of disadvantages and improvements of the two one-class classifiers are summarized.
-
Computer Engineering. 2011, 37(5): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2011.05.064Concerning the fact that the standard Particle Swarm Optimization(PSO) algorithm has the problem of population diversity lose and premature convergence, using the feature of independent individual behavior of social animals in nature for reference, this paper proposes the concept of individual state. A Particle Swarm Optimization(PSO) algorithm based on individual state and state transition is proposed and tested with several typical benchmark functions. The result indicates that the algorithm is significantly superior to standard PSO in performance of optimization. Compared with other improved algorithms, it is also excellent in performance of optimization.
-
Computer Engineering. 2011, 37(5): 193-195. https://doi.org/10.3969/j.issn.1000-3428.2011.05.065Aiming at the case retrieval problems in the Case-Based Reasoning(CBR) system, in the light of the idea of the K-means algorithm, this paper designs a clustering algorithm and a case retrieval algorithm respectively. In terms of the deficiency of the K-means algorithm, this paper improves the selecting rules of initial values as well as the case retrieval algorithm. It analyzes the selecting rules of sample case on the basis of case-weight, and deeply discusses the case clustering algorithm and retrieval algorithm. Experimental results show that this method can efficiently raise the efficiency of case retrieval and enhance the recall rate of the retrieval results.
-
Computer Engineering. 2011, 37(5): 196-198. https://doi.org/10.3969/j.issn.1000-3428.2011.05.066
The K-nearest-neighbor algorithm is adopted in the classification of the Kazakh text, while in characters chosen, a method that integrates language information and statistical information from the training corpus is applied. The weight of these characters is computed from three parameters: word frequency, centralized degree, decentralized degree. After training, the vector space model of the Kazakh text categorization is got, and the Kazakh text through K-nearest-neighbor algorithm is classified. Experimental results show that this method is feasible.
-
Computer Engineering. 2011, 37(5): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2011.05.067In order to solve the problems of optimization efficiency and inferior local search of quantum genetic algorithm whose coding is based on bloch coordinates, this paper proposes two improvements, combines local search with global search which is based on comparative population, and expands the search space from one sphere to three-sphere according to the characteristics of three chains. With the application of function extreme optimization of multi-variables, simulation results show that the improved algorithm has lower generation, higher efficiency, diverse populations, and it proves that the improvement is efficient.
-
Computer Engineering. 2011, 37(5): 202-203,206. https://doi.org/10.3969/j.issn.1000-3428.2011.05.068According to the characteristic of gene expression data, this paper proposes a gene expression data visualization clustering method based on spring model. It projects the multi-dimensional gene expression data to 2D space, and keeps some temporal-spatial features in the original data after mapping. Experimental results demonstrate that the method is effective and can discover the co-expression pattern and cluster structure in the data.
-
Computer Engineering. 2011, 37(5): 204-206. https://doi.org/10.3969/j.issn.1000-3428.2011.05.069To improve the performance of Particle Swarm Optimization(PSO) algorithm, nonlinear strategy based on sinusoid, tangential and logarithmic curve is proposed in this paper. At the same time, a strategy on processing the particles out of range is proposed. Several classical benchmark functions are used to evaluate the strategies. Experimental results show that for continuous optimization problem, the proposed sinusoid and logarithmic curve strategies gain advantages over the classical linear strategy, while the linear strategy outperforms the tangential curve strategy.
-
Computer Engineering. 2011, 37(5): 207-209,212. https://doi.org/10.3969/j.issn.1000-3428.2011.05.070As traditional cluster methods focusing on the homogeneous data can not meet the need of simultaneous clustering of heterogeneous data, the precious is low, and the readability of the labels is poor, this paper presents a co-clustering algorithm for heterogeneous data based on resistive network. In the algorithm, the heterogeneous related data is transformed into a resistive network with multi-part graph structure for the following computing of eigenvalue and clustering. After co-clustering, a clustering result structure can be obtained, that in the structure one class includes multiple heterogeneous data which can be each other’s label, and the readability of the labels is high. Experimental results prove that the data clustering algorithm is achievable and effective.
-
Computer Engineering. 2011, 37(5): 210-212. https://doi.org/10.3969/j.issn.1000-3428.2011.05.071Feature weight algorithm has great impact on the classification results. Traditional algorithms don’t consider distribution information among and inside classes. This paper introduces a new improvement ideas of skew information among classes, distribution information inside a class and weight adjustment factor, then puts forward a new term weight algorithm based on WA-DI-SI after in depth analysis of improvements method, and uses SVM and na?ve Bayesian classifier to check its validation. The method is better than others and proves that the improved algorithm is feasible.
-
Computer Engineering. 2011, 37(5): 213-215,218. https://doi.org/10.3969/j.issn.1000-3428.2011.05.072In order to effectively reduces the cost of time and space of text processing, with reference to the theory that only a part of signal from brain cells can reach pallium, and the theory that axon signal strength is reduced with distance increment from main body of neural cells, signal transmission theory-based dimension reduction algorithm of neural network is presented. This algorithm optimizes the structure and training algorithm of neural network and points out that there exists a great number of component approaching 0 in LTM between neurons in text space, that is there exists many unnecessary connection between neurons. So the basis of text dimension reduction is formed based on this discovery. The equivalent to and even higher classification accuracy is possessed in dimension reduction space than that of original space at the lower cost of time and space by the above algorithm.
-
Computer Engineering. 2011, 37(5): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2011.05.073This paper presents a new method for optimization of Elastic Graph Matching(EGM) algorithm in face recognition. After face image graph is composed of feature vector extracted from 2D Gabor wavelet, labeled graph vector is obtained. The proposed algorithm adopts the Principal Component Analysis(PCA) and FLD algorithm reduces dimensionality of labeled graph vector. In comparison with the conventional methods, the proposed approach can obtain satisfactory results in the perspectives of recognition rates and speeds.
-
Computer Engineering. 2011, 37(5): 219-220,223. https://doi.org/10.3969/j.issn.1000-3428.2011.05.074Traditional face recognition algorithm based on Bayesian space is assumed to meet the Gaussian distribution of the sample space. In fact the sample space is very complicated and does necessarily satisfy the Gaussian distribution. This paper presents a new face recognition algorithm in the Bayesian space. By setting the image gray-level threshold and counting the frequency of the pix and calculate the class conditional probability density, this algorithm gets posterior probability by the Bayesian formula. This method overcomes the shortcomings of traditional Bayesian approach hard to find within-class and between-class covariance matrix, and it is easy to use. Experimental results show that the method is feasible, superior to the traditional algebra-based face recognition algorithms(PCA, LDA and PCA + LDA).
-
Computer Engineering. 2011, 37(5): 221-223. https://doi.org/10.3969/j.issn.1000-3428.2011.05.075In order to escape from premature convergence and lack of good direction in particles, the evolutionary process, quantum technology and immunologic mechanism are employed, and an adaptive immune quantum-behaved Particle Swarm Optimization(PSO) algorithm is provided. Meanwhile, according to larger calculation and longer consumed time, parallel computation technology is introduced into the provided algorithm. Simulation experiments show that the PSO algorithm has better performance.
-
Computer Engineering. 2011, 37(5): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2011.05.076The obvious shortcomings of Possibilistic C-Means(PCM) algorithm is that the performance will be significantly reduced for high dimensional data sets and it can not effectively identify the useful subspace embedded in the high dimensional space. In order to overcome the weakness, the subspace clustering mechanism is introduced and the Subspace Possibilistic Clustering(SPC) algorithm is presented. It not only has the advantages of PCM algorithm but also has the characteristic of the classic subspace clustering algorithms. Namely, it has good adaptability to high dimensional data, and can detect the subspaces for each cluster effectively. Simulation experiments with synthetic and real data sets demonstrate the effectiveness and the merits of SPC.
-
Computer Engineering. 2011, 37(5): 227-229. https://doi.org/10.3969/j.issn.1000-3428.2011.05.077This paper proposes a scene image categorization method based on structure and texture fusion. It adopts a two-layer classifier. The first classifier classifies all the scene images based on structure features, and similar categories can also be computed based on the results. The second classifier only classifies similar images and both of results are combined to predict the scene image category. Experimental result shows that categorization accuracy can be improved based on the method.
-
Computer Engineering. 2011, 37(5): 230-231,234. https://doi.org/10.3969/j.issn.1000-3428.2011.05.078This paper proposes a framework which allows any region-based active contours can be re-formulated in a local way. The energy function of this framework consists of a geometric regularization term that penalizes the length of region boundaries and a data fitting term in a local region. It uses a slide window function to extract the local entropy according to the relationship of spatial arrangements of image pixel, which can map intensity space of image to local entropy space. Another window function can be used to extract local region information so that getting the localizing region-based active contours framework. It takes CV model as an example to demonstrate it. The analysis and comparison of the two familiar window functions also can be done. Experimental results for images illustrate that this model can segment the cluttered images.
-
Computer Engineering. 2011, 37(5): 232-234. https://doi.org/10.3969/j.issn.1000-3428.2011.05.079Graph cuts is an interactive segmentation algorithm based on boundary and region properties of objects in images. The region term in conventional graph cuts is based on Gaussian Mixture Model(GMM). However, it is not only a slow process, but sometimes it can’t describe the distribution of pixels in objects precisely. This paper proposes an improved algorithm based on K-means clustering graph cuts. Its evaluation is performed using both phantoms and real Magnetic Resonance Imaging(MRI) of brain, the effectiveness and efficiency of the proposed algorithm are showed. And in particular, an accurate and robust results in segmenting images with noise and intensity non-uniformity with a low computational cost can be achieved.
-
Computer Engineering. 2011, 37(5): 235-237,240. https://doi.org/10.3969/j.issn.1000-3428.2011.05.080Ice charts are recognized to be of significance in both shipping safety in polar regions and climate research, however they also have disadvantages on providing either pixel-level positions or accurate concentrations. An edge-preserving regional MRF image segmentation based on ice chart is then proposed, which extracts sub-images form accompanying Synthetic Aperture Radar(SAR) image, then does SRAD filtering, watershed initial segmentation and regional MRF segmentation one by one. It combines all the sub-images to get the final segmentation. It achieves the combination of manual interpretation and computer interpretation, gains pixel-based map, and has advantages on accurately locating object edges, efficient segmentation, parallel processing and so on. The high performance of the proposed method is demonstrated on the segmentation of SAR sea ice images of polar regions.
-
Computer Engineering. 2011, 37(5): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2011.05.081In order to show the morphological changes during leaf wilting, this paper proposes a new method to model leaf wilting. The method extracts leaf profile using image processing, generates veins using Runions’s method, and generates 2D mesh based on leaf profile and generated veins. Based on this, the paper proposes to control the 2D mesh based on control curves to achieve the bending deformation during leaf wilting, and designs the control curves through experiments. Experimental results show that the method can simulate morphological changes in the process of leaf wilting.
-
Computer Engineering. 2011, 37(5): 241-243. https://doi.org/10.3969/j.issn.1000-3428.2011.05.082For the difficulties of auto-body ECU’s software upgrade, a method of ECU’s upgrade based on CCP and CAN bus is presented after illustrating the principle of In Application Programming(IAP) technology. Besides, the implementation on the XC167CI is given in the paper. The processing method of load file in the load tool and the implementation method of bootloader are expounded. Experimental result shows that the system not only achieves the function of application code upgrade but also runs stably.
-
Computer Engineering. 2011, 37(5): 244-246. https://doi.org/10.3969/j.issn.1000-3428.2011.05.083GSS-2 type of marine gravity meter sensor has high measurement precision. After years of use, mechanical structure becomes steadier. With the rapid development of electronic information technology, the old measurement system becomes the major obstacle of high-precision measurement. This paper designs a hardware monitoring and control system using a stable Programmable Logic Controller(PLC) as core controller. Based on Modbus protocol, it develops a multi-functional monitoring and control software as the host computer. Experiments show that the hardware system performs steady and function of software is user-friendly. The system fully meets the design and use requirements.
-
Computer Engineering. 2011, 37(5): 247-248,252. https://doi.org/10.3969/j.issn.1000-3428.2011.05.084Traditional verification method is not suitable for complex equipment MTTR verification. This paper presents a method of verifying the group which comprises sub-system of the complex equipments based on degree of similarity of MTTR curve. It determines similarity degree of curves by similarity, and group curves by stratified keystone grouping method. It verifies groups by traditional verification method. It presents a new method for verification of complex equipment MTTR.
-
Computer Engineering. 2011, 37(5): 249-252. https://doi.org/10.3969/j.issn.1000-3428.2011.05.085This paper presents an automatic test-configuration-generation method to test and diagnose all stuck-on, stuck-off faults in Programmable Interconnect Points(PIP), open, stuck-at faults in segments and all bridge faults between segments connecting to the same switch matrix. By searching all nodes of routing resource graph by direction, the proposed method generates total and partial configurations and then uses JTAG boundary scan chain to apply test vectors on them and readback results. Experimental results show that short time of configuration is required to cover all faults.
-
Computer Engineering. 2011, 37(5): 253-255. https://doi.org/10.3969/j.issn.1000-3428.2011.05.086To solve the problem of network topology for the distribution network management system, a distribution network topology analysis algorithm based on Geodatabase model is presented. Geodatabase data model and network topology model are introduced. The mathematical model of distribution network is defined. The distribution network topology model is established, and the algorithm flow is designed. Cases of the topology generation and analysis of power supply in distribution network show that the algorithm is simple in structure, the algorithm flow is clear, and it can meet the needs of the topology analysis in distribution networks.
-
Computer Engineering. 2011, 37(5): 256-257,260. https://doi.org/10.3969/j.issn.1000-3428.2011.05.087In order to realize voice conversion, a satisfied voice conversion corpus needs to be built up. This paper proposes an automatic corpus selection algorithm based on the semi-syllable model. Because the number of corpus sentences is small for voice conversion, the semi-syllable is chosen as the basic unit of the corpus. The algorithm automatically selects corpus from original corpus. An evaluation function is utilized to score sentences from original corpus according to the number and the kind of semi-syllable. When the number of chosen sentences is 615, the set of selected text covers 97.8% of the semi-syllables. The covering rate, coverage efficiency and sparse rate are obviously better than that of conventional algorithms.
-
Computer Engineering. 2011, 37(5): 258-260. https://doi.org/10.3969/j.issn.1000-3428.2011.05.088An SOA-based enterprise integration platform called JSSOA is presented. Cored on Enterprise Service Integration(ESI) middleware, JSSOA supports transparent integration of heterogeneous systems and services, MDA-based and business user oriented process modeling and service composition, semantic and QoS based service finding and service oriented UI creating. JSSOA simplifies the creation, running and maintenance of SOA-based applications by encapsulating the complicate details of SOA technology.
-
Computer Engineering. 2011, 37(5): 261-263,266. https://doi.org/10.3969/j.issn.1000-3428.2011.05.089Simulation of electromagnetic wave propagation in complex terrain environment needs powerful computing ability. Parallel computing using cluster which is based on MPI can solve this problem commendably. This paper puts forward a parallel algorithm of electromagnetic wave propagation in complex terrain environment, and designs experiments considering task granularity and capability in parallel process. Simulation speed is improved in a cluster environment in laboratory. Methods of choose an appropriate task granularity for similar parallel problems is proposed.
-
Computer Engineering. 2011, 37(5): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2011.05.090Reasonable route planning should consider drivers’ habits and psychological features. Delay and turning types such as left-turn, through and right-turn have different effects on driver’s psychological feeling. Considering the intensive road network and short distance between intersections in urban area, two improvements are conducted on classic A* algorithm for route planning. It introduces delay at intersection to the cost function of route, and puts forward the turning coefficient γ to represent drivers’ psychological feeling upon the turning type, and adds it to the cost function too. Results of the simulating example indicate the shortest planned route by improved algorithm can avoid the left-turn efficiently, compared with the classic algorithm, the new algorithm concords better with the real drivers’ habit.
-
Computer Engineering. 2011, 37(5): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2011.05.091To deal with asymmetric information, dynamic environment as well as vagueness and uncertainty of QoS in service negotiation, this paper proposes a dynamic service negotiation model based on interval similarity. This model can be used to forecast the negotiation strategies of the counterpart via using interval similarity and interval estimation, and on this basis to make optimal counter-strategies. A numerical example shows that dynamic service negotiation model is closer to reality behaviors compared with static, and it can effectively improve negotiation efficiency in the dynamic service negotiation environment.
-
Computer Engineering. 2011, 37(5): 270-272,275. https://doi.org/10.3969/j.issn.1000-3428.2011.05.092A novel transparent computing system called HCTS is proposed in this paper. HCTS adopts the hierarchical cache strategy in client and server respectively to improve the I/O performance of the system. In order to improve the cache hit ratio according to the given environment of transparent computing, this paper presents a modified LRU replacement algorithm called LRU-AFS based on the count threshold of data accessing times, which is used to distinguish between frequently used data and rarely used data. Test results show that, with growing in number of clients in LAN, HCTS can better improve and enhance the client I/O performance compared to general TS, reduce the network traffic dramatically, shorten the boot time significantly and increase the random read-write throughput of clients effectively.
-
Computer Engineering. 2011, 37(5): 273-275. https://doi.org/10.3969/j.issn.1000-3428.2011.05.093The majority of current Latin hypercube design optimization employs the orthogonal property or homogeneous property measurement as the single optimization criterion. An experimental design method of multi-objective optimization based on modified ILS algorithm is presented to cover the shortage of single optimization criterion. The orthogonal property and homogeneous property of Latin hypercube design are optimized at the same time, and in comparison with several typical experimental design methods, its superiority is exemplified.
-
Computer Engineering. 2011, 37(5): 276-278,281. https://doi.org/10.3969/j.issn.1000-3428.2011.05.094Binary program comprehension and analysis are based on Control Flow Graph(CFG) which is the key to reconstruct and reengineering a program and is the basis of software reversing engineering. Classic CFG restoring algorithm that is relevant to program structure and complier information is not applicable to some other binary program. Aiming at this problem, this paper presents a new CFG restoring algorithm that is based on static simulation strategy. The new algorithm derives from the classic CFG restoring method. It compares the new algorithm with other CFG recovery algorithms on performance. Results show that the algorithm can restore control flow from binary program more completely than others.
-
Computer Engineering. 2011, 37(5): 279-281. https://doi.org/10.3969/j.issn.1000-3428.2011.05.095A Proteus simulation model for a processor with self-defined instruction set is implemented based on the study of Proteus C++ programming interface. The instantiated model is merged into and further tested with a virtual board level system. By modeling processor with Proteus, designer can kick off board level simulation far before the fabrication of a real processor chip, and can have a convenient verification tools, and start hardware-software co-design in very early stages.
-
Computer Engineering. 2011, 37(5): 282-284,287. https://doi.org/10.3969/j.issn.1000-3428.2011.05.096This paper introduces a multi-protocol data stream conversion method based on characteristic keyword, in which the data-frame format is described by characteristic keywords, and the data stream parse and conversion program are independent of the communication protocol by separating the description of communication protocol data frame format from the parse and conversion program. This method uses the stable procedure to process the unstable data streams. It can avoid writing special parse and conversion program for different communication protocol, and make the program more flexible and more adaptable.
-
Computer Engineering. 2011, 37(5): 285-287. https://doi.org/10.3969/j.issn.1000-3428.2011.05.097Tile caching can reduce WebGIS server load effectively, however, the existed tile caching technology only works well on data that is never or seldom updated. This article presents a dynamic tile caching strategy, which makes tile caching have the ability of updating in real time and can be applied to editable WebGIS. The implementation and experimental results show that editable WebGIS works well with this caching strategy, the response speed of editable WebGIS improves obviously and this caching strategy also meets the actual needs of the trade.
-
Computer Engineering. 2011, 37(5): 288-290. https://doi.org/10.3969/j.issn.1000-3428.2011.05.098Aiming at the problem of listening exercise in English learning, this paper proposes a speech repeating system which adjusts the speaking rate with TD-PSOLA algorithm and can display the subtitle of speech by large vocabulary connected speech recognition method. With the system, users can select the speech to repeat by selecting subtitle and modify speaking rate of selected speech real-time. The modified speech by system achieve 4.1 of the average Mean Opinion Score(MOS), which is close to the quality of the original voice. Result of speech recognition evaluation shows that the word level accuracy of speech recognition on pure English learning material is 70.8%.
-
Computer Engineering. 2011, 37(5): 291-封3. https://doi.org/10.3969/j.issn.1000-3428.2011.05.099In the video stitching, registration error and moving objects lead to ghost error. It brings about the loss of high-frequency content by simple fusion method, and complex fusion algorithm is hard to meet real-time fusion. To solve these problems, this paper uses the improved Harris feature operator, and the improved RANSAC algorithm to reduce image registration error. It combines with the bundle adjustment and puts forward a new fusion method. Through the overlapping regions of the border to strike and morphology corrosion science operations, it determines the need for integration of the pixel, and then as a weighted combination of trigonometric functions to carry out integration. A large number of experimental results show that this method has a good effect of real-time stitching.
2024
Volume 50 No 4
Volume 50 No 4
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428