15 March 2013, Volume 39 Issue 3
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Computer Engineering. 2013, 39(3): 1-6. https://doi.org/10.3969/j.issn.1000-3428.2013.03.001Automatic Train Protection(ATP) system is a safety-critical system to ensure the train running safety. The system has various functions and complex logic, which makes the development difficult. To this end, a model-based method is presented to develop ATP application software, in which interface models, status models, and control flow models are used to clearly and correctly describe application software functions and their implementation processes. The functions of the developed software are further verified by simulations and tests. The obtained results confirm that the function logic is simplified effectively with this method, making the software development easy. What’s more, human errors and faults are also reduced in this process.
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Computer Engineering. 2013, 39(3): 7-11. https://doi.org/10.3969/j.issn.1000-3428.2013.03.002Session Initiation Protocol(SIP), as a core session control protocol of VoIP, its base functions are a bit simple. It can not meet the needs of force disconnect which is a core business of wireless train dispatching system. To the question above, this paper provides the architecture of the wireless railway dispatching system under the environment of WiMAX, extends the SIP message methods and transactions, designs the signaling process of new SIP message method, and provids the extension scheme on the client side and server side. Experimental results show that this scheme can meet the establishing time requirement of force disconnect on railway, and can realize force disconnect successfully.
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Computer Engineering. 2013, 39(3): 12-15. https://doi.org/10.3969/j.issn.1000-3428.2013.03.003For the designing complexity of CTCS-2 system, this paper proposes the method combining Unified Modeling Language(UML) and Symbolic Model Checking(SMC) for modeling and formal verification. It analyzes the mode conversion scene of CTCS-2 on-board equipment. The mode conversion scene of CTCS-2 on-board equipment is modeled by using the UML, and UML class diagrams and UML state diagrams are gotten as well, through formulating some exchanging rules to extend and abstract UML model and exchanging it to the NuSMV model. The property of to be verified system and system Symbolic Model Verifier(SMV) model are inputted to symbolic model verifier to check. The verified results are true, and it shows that mode conversion scene of CTCS-2 on-board equipment has activity, accessibility and security.
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Computer Engineering. 2013, 39(3): 16-19. https://doi.org/10.3969/j.issn.1000-3428.2013.03.004For a safety critical computer, large-scale data like database which has to be transferred in an instant time cannot be voted directly. This paper proposes a database update algorithm for safety critical computer based on status vote, which is to vote the database status instead of database itself. This algorithm can solve the problem of voting too much data in a short time, and compare versions of database of different modules in real time. A Markov model is built to calculate the safety and reliability of this algorithm. The results show that this algorithm meets the update requirement of safety critical computer.
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Computer Engineering. 2013, 39(3): 20-24,30. https://doi.org/10.3969/j.issn.1000-3428.2013.03.005A multi-function, easily extensible and portable tracking and monitoring system is designed for traction and drive unit to meet the growing requirements of high-speed Electric Motor train Units(EMUs), which is increasingly complex for real-time monitoring system. The design principle of the embedded hardware system based on the modular structure of CPCI bus is presented, and the realization of software functions such as on-line real-time data processing, offline data analysis, and human-machine interaction is put forward on the basis of LabVIEW development platform. Furthermore, the Visual Instrument(VI) design and scheduling mechanism based on state-machine are elaborated, and the measurement algorithm and its implementation of the traction motor’s input power and constantly changing signal frequency of the monitoring system is also analyzed. The system is applied in certain models of the high-speed EMUs, and its stable operation, flexible settings, high accuracy and good application effect makes it provide a scientific guarantee for the safe operation of the high-speed EMUs.
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Computer Engineering. 2013, 39(3): 25-30. https://doi.org/10.3969/j.issn.1000-3428.2013.03.006This paper proposes a visual inspection and classification algorithm of rail surface defect. An overall structure of the visual inspection and classification system for rail surface defects is designed. It extracts the rail surface subarea based on horizontal projection method, combines the inspection result based on logic or operation, and classifies the defect based on BP neural network. Experimental results show that the algorithm is able to detect and identify the two rail surface defect, scarring and corrugated abrasion accurately, the accuracy of classification is 99% and 95%.
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Computer Engineering. 2013, 39(3): 31-35,45. https://doi.org/10.3969/j.issn.1000-3428.2013.03.007In order to overcome the verification and test difficulties caused by the absence of sensors when developing safety computer systems, a model-based simulation system for safety computer system is presented. Modeling on real sensors to control real hardware, by the method of combination of hardware and software, the simulation system provides actual physical input and output signals for safety computer system. At the same time, by modifying the model parameters, it can provide no damage fault injection for safety computer systems. The test results show that the simulation system can effectively verify the security, reliability and availability of safety computer systems and can speed up the development process of safety computer systems.
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Computer Engineering. 2013, 39(3): 36-40. https://doi.org/10.3969/j.issn.1000-3428.2013.03.008According to the temporal characteristic of Unified Modeling Language(UML) sequence diagram, this paper proposes a formal method of UML sequence diagram based on temporal description logic ALCQIUS. The temporal expand syntax and semantics are given, the theorem of the assertion formulas of ALCQIUS is studied, the consistency reasoning algorithms is put forward and its decidability is proved through the study of the assertion formulas of ALCQIUS. Taking the public security alarm system as a example, the formal specification and formal checking of UML sequence diagram are explained through ALCQIUS, and the ALCQIUS provides more reasonable logic foundation for the formalization for UML sequence diagram.
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Computer Engineering. 2013, 39(3): 41-45. https://doi.org/10.3969/j.issn.1000-3428.2013.03.009In data mining process, it only considers the weight of data items, or only considers the temporal semantics of data, resulting in incomplete mining results. For the above-mentioned problem, the weighted association rules, temporal association rules and the periodicity of temporal data are studied. The weights, K-support bounds and periodicity are introduced into temporal association rules. The algorithm of mining weighted temporal association rules based on periodicity is proposed. Applying the algorithm in audit data of a management system, results show that this algorithm can accurately mine the weighted temporal association rules, and with the same time complexity, it makes the mining of association rules more meticulousness than weighted association rule algorithm.
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Computer Engineering. 2013, 39(3): 46-50,55. https://doi.org/10.3969/j.issn.1000-3428.2013.03.010Existing outlier detection algorithms most require a predetermined number of outlier. If it is not accurate, it can greatly reduce the accuracy of outlier detection algorithm. Aiming at above problem, a detection method of outlier based on probability is proposed. The detection method combines the DBSCAN algorithm with variance from median algorithm to cluster detection data set, and extracts suspicious outliers which are not belonging to any cluster. These suspicious outliers are detected by the definition of outlier, and outliers are determined. The method are insensitivity with noisy data. The data disposed by this method is irrelative to the time scales. And it does not need to set the number of outlier and cluster. Experimental results on IRIS show that this algorithm can detect outliers effectively.
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Computer Engineering. 2013, 39(3): 51-55. https://doi.org/10.3969/j.issn.1000-3428.2013.03.011In order to solve the problem that how to build the scientific and reasonable index system in weapon and equipment demonstration, the construction method of index architecture based on group decision-making is proposed. Using the group decision-making organization method that combination of distributed synchronization and distributed asynchronization, the process is divided into index architecture discussion and the index value assignment. The emphasis is laid on design of subject generation function and comprehensive discussion method used for the index architecture discussion. According to the construction method, the computerized system of building index system has been developed and applied.
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Computer Engineering. 2013, 39(3): 56-62. https://doi.org/10.3969/j.issn.1000-3428.2013.03.012Aiming at the problem of software-intensive degree incrementing tendency of Avionics Electronics(AE) and the ambiguity and incompleteness of AE software requirements engineering, this paper constructs AE system software requirement knowledge ontology and its knowledge framework. It constructs the AE generalized ontology and chooses the Flying Control(FC) to construct the FC domain ontology. It estimates the quality of FC domain ontology. The results of estimation show that the quality level of FC domain ontology is medium according to the maximum membership degree principle. This result shows that it is necessary to improve the quality of developing techniques and structure display.
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Computer Engineering. 2013, 39(3): 63-66. https://doi.org/10.3969/j.issn.1000-3428.2013.03.013Aiming at the security problem of Web database system in multi-homing and mobility network environment, by introducing the Policy Execute Module(PEM), a Web database security model based on trusted computing and Host Identity Protocol(HIP) is proposed. HIP validates the platform while trusted computing guarantees platform’s security. This model is well safe, and can support host’s mobility and multi-homing while has defense against inner threat such as virus and Trojan horse and network attack such as denial of service and man-in-the-middle.
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Computer Engineering. 2013, 39(3): 67-71,76. https://doi.org/10.3969/j.issn.1000-3428.2013.03.014Aiming at the disadvantage of waste of energy in the existing data gathering methods based on the dense projection, using the compressive sensing theory, this paper proposes an improved data gathering method based on the optimal projection. It takes the transmission overhead into consideration and designs the optimal projection matrix for avoiding the unnecessary projecting operation, and proves that the matrix meets the RIP nature, an optimized data gathering tree with having the minimum added value of transmission cost is designed for gathering the measurements of each node. Simulation experimental results show that the performance of the method is superior to the traditional methods in terms of the reconstruction accuracy of data and energy efficiency.
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Computer Engineering. 2013, 39(3): 72-76. https://doi.org/10.3969/j.issn.1000-3428.2013.03.015According to the characteristics of the wireless channel, channel estimation algorithms based on the factor graph are proposed for Orthogonal Frequency Division Multiplexing(OFDM) system to improve the precision of channel estimation and bandwidth efficiency, which include two-dimension joint channel estimation and one-dimensional channel estimation algorithm. Time-varying frequency-selective fading channels can be modeled as one order autoregressive processes and approximating messages as Gaussian distribution, a novel channel estimation and symbol detection method for OFDM system is deduced by applying sum-product algorithm on the factor graph. Simulation results show that the algorithm can achieve good performance with low computational complexity.
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Computer Engineering. 2013, 39(3): 77-81,86. https://doi.org/10.3969/j.issn.1000-3428.2013.03.016Aiming at the disadvantage of the existing data gathering methods, this paper proposes a Target Localization Algorithm(TLA) based on compressive sensing. Sensor networks is divided with multiple grids, compared with the grid number, the number of targets is sparse, so the localization problem is transformed into the sparse signal reconstruction problem, and a measure matrix is designed based on the energy attenuation characteristics of target, and the paper proves that the matrix meets the RIP nature. TLA is designed for achieving the precise positioning of the target. Theoretical analysis and experimental results show that the performance of the method is superior to the traditional methods in terms of the target localization error and energy efficiency.
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Computer Engineering. 2013, 39(3): 82-86. https://doi.org/10.3969/j.issn.1000-3428.2013.03.017In view of the inferior outage performance of multihop channel and the complex receiver of multihop diversity channel, an improved Decode-and-forward(DF) multihop relay system is proposed based on DF multihop relay system and DF multihop diversity relay system. The proposed system can realize a tradeoff between system performance and complexity. Outage probability of the proposed system is derived, and power allocation optimization problem is formulated and evaluated by minimizing the outage probability with the use of lagrange multiplier method. Simulation results show that the proposed system has better outage performance than traditional multihop relay systems. Besides, the optimum power allocation can enhance system performance, especially if the number of relays is large.
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Computer Engineering. 2013, 39(3): 87-92,98. https://doi.org/10.3969/j.issn.1000-3428.2013.03.018Aiming at the large-scale network scene of Vehicular Ad Hoc Network(VANET), this paper proposes a cluster routing protocol based on motion state. It computes link hold time and connection degree of nodes with one jump neighbor node, confirms cluster head node through judge node priority and these two parameters. In the maintenance process, it dynamically confirms the scope of the neighbor nodes according to distance and relative velocity between members and cluster heads. Simulation result shows that this protocol can improve the stability of the cluster, and reduce the end-to-end delay, it has very high packet delivery ratio and cluster duration time than CBRP protocol and SWBCA protocol.
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Computer Engineering. 2013, 39(3): 93-98. https://doi.org/10.3969/j.issn.1000-3428.2013.03.019This paper researches a new energy-ef?cient MAC protocol which is based on asynchronous duty cycling. Predictive- Wakeup MAC(PW-MAC) minimizes sensor node energy consumption by enabling senders to predict receiver’s wakeup times. However, PW-MAC protocol performs poorly in the dramatically changing traffic Wireless Sensor Network(WSN). Based on this problem, the paper proposes a Adaptive Duty Cycle MAC(ADC MAC) protocol that dynamically adjusts the node’s duty cycle based on the changing traffic. Simulation results show that ADC MAC reduces the packet transmission delay by 30% and increases the packet successful delivery ratio by 35% compared with PW-MAC.
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Computer Engineering. 2013, 39(3): 99-104,110. https://doi.org/10.3969/j.issn.1000-3428.2013.03.020The resource scheduling mechanisms used in WiMAX network and Wireless Access in Vehicular Environments (WAVE) network are different. Aiming at the need of interoperability in the mobile gateway, a feedback based two-level scheduling mechanism is proposed. A weight-based round-robin scheduling is used in WiMAX network, while a feedback-based EDCA access scheme is designed in WAVE network to adjust transmission rate of MAC layer in WAVE to accommodate scheduling scheme used in WiMAX. Simulation results indicate that compared with other methods, the proposed scheme can reduce the average delay below to 20 ms, and cut 50% queue length in gateway node.
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Computer Engineering. 2013, 39(3): 105-110. https://doi.org/10.3969/j.issn.1000-3428.2013.03.021This paper presents a kind of reliable transmission protocol with dynamic adjustment for caching position, which makes a good compromise between transmission reliability and energy consumption. This protocol is based on the intermediate nodes cache data packet, so the link node can be divided into near-source node and near-sink node according to communications distance. Dynamically adjustment of the node section for cache packet is done in accordance with link quality. To make more uniform distribution of cache, the packets are normally distributed to cache at their corresponding section. Simulation and energy consumption model based on Markov analysis show that, this protocol can improve the transmission reliability with reduced energy consumption.
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Computer Engineering. 2013, 39(3): 111-117. https://doi.org/10.3969/j.issn.1000-3428.2013.03.022This paper studies on-demand acquisition decision problem for mass multi-dimensional information in Internet of Things(IOTs). It converts this problem to the network subnet construct issues and establishes an integer nonlinear multi-objective optimization model. For specific event, according to the deployment and configuration of sensors, determine collection of nodes, each node in the data upload sensor types as well as the data upload time interval. It uses genetic algorithms to solve multi-objective optimization, and balances data flow and the amount of information transmission requirements after collection. The results of simulation case prove the correctness and validity of the model and its solution.
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Computer Engineering. 2013, 39(3): 118-122. https://doi.org/10.3969/j.issn.1000-3428.2013.03.023To detect a composite event efficiently in Wireless Heterogeneous Sensor Networks(WHSN) which has huge amounts of variant wireless sensor nodes, this paper proposes an algorithm to detect composite events based on the concept of Dominating Set(DS). It looks for a dominating set in the network as the set of local decision nodes. Local decision nodes make local decisions about composite events within a radius of local decision. Simulation results show that the algorithm improves the accuracy of detection, reduces the consumption of energy compared with existed Collaborative Event detection and Tracking(CollECT) algorithm and Connected Dominating Set(CDS) algorithm.
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Computer Engineering. 2013, 39(3): 123-127. https://doi.org/10.3969/j.issn.1000-3428.2013.03.024This paper imports Low Duty Cycle(LDC) technology into opportunistic networks for enlarging the life cycle of opportunistic network. The nodes encounter problem in LDC is studies. The effect on encounter probability of nodes and LDC opportunistic network with the change of node moving speed, communication range and duty cycle are analysed. Simulation results show that low duty cycle technology can significantly extend the life cycle of opportunistic network while losing a small number of meet opportunities.
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Computer Engineering. 2013, 39(3): 128-131,145. https://doi.org/10.3969/j.issn.1000-3428.2013.03.025In order to solve the short-wave burst communications carrier synchronization, this paper proposes a low-complexity frequency offset estimation algorithm. It makes the frequency offset of received signal with cycle of law through phase folding phenomenon. In order to reduce algorithm complexity and realize fast synchronization, it can avoid the traditional autocorrelation calculation and discrete Fourier transform by estimating deviation with periodic law. Matlab simulation result shows that this algorithm has the characteristics of high estimation precision, wide capture range and low computational complexity. It is suitable for emergency communication frequency offset estimation.
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Computer Engineering. 2013, 39(3): 132-136,151. https://doi.org/10.3969/j.issn.1000-3428.2013.03.026In order to solve the problem of low routing performance caused by sensor or link failures in Three Dimensional Underwater Acoustic Sensor Networks(3D UWASNs), this paper presents a Multi-path Fault-tolerant Routing(MFR) protocol. In MFR, each sensor has a data structure called backup bin, which is utilized to construct main backup links and auxiliary backup links together with routing table for repairing routing path and ensuring normal data delivery. Simulation results show that MFR protocol can reduce node failure or link failures’ impact to the data delivery ratio and network throughput.
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Computer Engineering. 2013, 39(3): 137-141. https://doi.org/10.3969/j.issn.1000-3428.2013.03.027How to calculate the value of B in the critical path is the most key factor which affects the execution speed of traditional MD5 algorithm. In order to improve execution speed, this paper optimizes the critical path, and separates the add calculation to two steps to shorten the time of calculating value of B. Verilog Hardware Description Language(HDL) is adopted to describe the circuit structure and DC is used to get area and frequency data. Experimental result shows that execution frequency is 142.8 MHz and area is 85 678 μm2, and the improved algorithm’s speed is 1.989 times compared with traditional algorithm.
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Computer Engineering. 2013, 39(3): 142-145. https://doi.org/10.3969/j.issn.1000-3428.2013.03.028By analyzing Yao’s stream cipher scheme of Wireless Sensor Network(WSN), this paper finds a nonzero low times annihilator in the design of Boolean function, and reduces the attack complexity by algebraic attack. In order to enhance the security of WSN stream cipher scheme, this paper constructs a new Boolean function with the second-order concatenation. Compared with original Boolean function, algebra immune degree of the new function increases 1. Analysis results shows that attack complexity of the new scheme promotes the attack complexity from 255 to 266, proving that the new scheme can resist algebraic attack more effectively.
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Computer Engineering. 2013, 39(3): 146-151. https://doi.org/10.3969/j.issn.1000-3428.2013.03.029This paper proposes a light-weight authentication and key management scheme by using one-way hash function and an efficient symmetric cryptography algorithm, according to the security and efficiency problems of data collection applications in Wireless Sensor Network(WSN). It uses the message authentication code to achieve the integrality for transmitted messages, verifies the correctness of shared session key, and simply calls a random-number generator by using cyclic shift technique to generate different random numbers, thereby improving the computational performance of sensors and saving storage space. Analysis result shows that the calculated amount of this scheme includes (10+tb) hash calculations, six symmetric encryptions/decryptions and three XOR operations, and storage space is 80 bit. Compared with the similar schemes, it is more secure and effective.
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Computer Engineering. 2013, 39(3): 152-156. https://doi.org/10.3969/j.issn.1000-3428.2013.03.030The unlinkable secret handshake scheme proposed by Ateniese et al can not strictly distinguish different groups and thus its practicality is limited. This paper proposes a new unlinkable secret handshake scheme named USH(Unlinkable Secret Handshakes) by using the variant of message recovery signature. Based on the difficulty problem of collusion attack algorithm with k traitors, it achieves the strong unlinkability against group authority with reusable credentials. Compared with the previous schemes, USH provides the definite group division and more simple construction which also takes advantage on storage and computation costs.
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Computer Engineering. 2013, 39(3): 157-161. https://doi.org/10.3969/j.issn.1000-3428.2013.03.031In order to analyze the security risk of 802.11 Wireless Local Area Network(WLAN) on defensing sniffer attack, this paper presents a security assessment model based on Technique for Order Preference by Similarity to Ideal Solution(TOPSIS). By the characters of the wireless sniffer, combining with the Analytical Hierarchy Process, two evaluation systems which are the certainty of chance and the possibility of successfully attacking are established. According to the network statistics and expert experience data, judgment matrix is built up to calculate the weight of each assessment index. TOPSIS method is used to establish the risk assessment system. Modeling analysis result shows the rank of WLAN’s security status and the weak link that will cause risk, which makes it easy to strengthen security measures and improve the safety performance.
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Computer Engineering. 2013, 39(3): 162-166. https://doi.org/10.3969/j.issn.1000-3428.2013.03.032In order to solve the problem that taint tracking system can not realize cross-host dynamic taint tracking, based on Temu system, a taint tracking method based on Application Programming Interface(API) Hook is presented. It fulfills the interception of network I/O related system calls by Hook plug-ins, which embeds Hook services into API function calls to accomplish cross-host taint propagation. Taint data and information are encapsulated by Hook plug-in at sender. Hook plug-in analyzes data packets and marks taint data tainted according to taint information at receiver, so that cross-host dynamic taint tracking is realized. Experimental result indicates that the prototype system can implement cross-host taint propagation, which is helpful to application with dynamic taint tracking in distributed environment.
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Computer Engineering. 2013, 39(3): 167-173. https://doi.org/10.3969/j.issn.1000-3428.2013.03.033This paper proposes a Group Key Management Scheme Based on Threshold(GKMT). The idea of dynamic threshold secret sharing scheme to encrypt multicast streams is used in GKMT. When a user wants to join or leave a multicast group, it is need not to redistribute group key. It can greatly enhance the effectiveness of the scheme. Meanwhile, to enhance the scalability of the scheme, the original scheme is improved to LGKMT using the hierarchical control. Performance analysis result shows that GKMT and LGKMT schemes are superior to existing group key management scheme on key communication cost, suitable for the group communication network which group state often changes.
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Computer Engineering. 2013, 39(3): 174-177,181. https://doi.org/10.3969/j.issn.1000-3428.2013.03.034Aiming at the problem that Kernel Principal Component Analysis(KPCA) can not effectively use the feature of face symmetry, and generally lacks of training samples in face recognition, so the recognition rate is low. Therefore, this paper proposes a Symmetrical Kernel Principal Component Analysis(SKPCA) algorithm. This algorithm fully utilizes the face mirror symmetry, the odd symmetry samples and the even symmetry samples are received by mirror transforming for training samples. Odd/even symmetrical principal components are respectively extracted. A nearest neighbor classifier is employed to classify the extracted features. Experimental results show that this algorithm enlarges the number of training samples, when the polynomial order number is 2, the recognition rate of this algorithm is better than that of the KPCA algorithm, and recognition time is shorter than KPCA algorithm.
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Computer Engineering. 2013, 39(3): 178-181. https://doi.org/10.3969/j.issn.1000-3428.2013.03.035Aiming at the feature extraction problem for high dimensional data, this paper proposes a feature extraction method combining Generalized Low Rank Approximations of Matrices(GLRAM) and Diagonal Principal Component Analysis(DialPCA) to realize image recognition. It uses generalized low rank matrix to approximate original image, does diagonalization changing, and uses 2D Principal Component Analysis(2DPCA) to extract the correlation between the row and column of data matrix. Nearest neighbor classifier is adopted for recognition rates calculation. Experiments on FERET and ORL face databases show that under the pose illumination and expression changing circumstances, recognition rate of GLRAM Plus DialPCA is higher than single GLRAM or 2DPCA.
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Computer Engineering. 2013, 39(3): 182-186. https://doi.org/10.3969/j.issn.1000-3428.2013.03.036This paper researches the precise location method for patrolling electronic guards observing object in data layer and precise identification in decision layer data fusion problem. Individual observed object data in local coordinate is transferred into global coordinate system, and Kalman method is used to realize data fusion in data layer. Improvement multilevel D-S evidence theory fusion is used in decision layer data fusion, single guard different sensor information is fused, and then multiple electronic guards observed result sensor information is fused. Experimental results show that stability and reliability of data are improved and precision of target recognition is improved by 20%.
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Computer Engineering. 2013, 39(3): 187-190,196. https://doi.org/10.3969/j.issn.1000-3428.2013.03.037In order to resolve the difficulty that the choice of parameters influence the accuracy of Support Vector Machine(SVM) fault diagnosis model, a genetic-immune Particle Swarm Optimization(PSO) algorithm based on genetic evolution algorithm and immune selection algorithm is presented and used to optimize model parameters of SVM. The forecasting model based on a genetic-immune PSO algorithm and SVM is proposed and used to diagnose bearing fault. The results show that diagnosis model of SVM optimized by genetic-immune PSO algorithm can achieve automatic optimization of parameters, increase diagnosis accuracy of the conventional cross-validation algorithm, and is more fitting to classify the faulty samples scattered greatly.
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Computer Engineering. 2013, 39(3): 191-196. https://doi.org/10.3969/j.issn.1000-3428.2013.03.038Aiming at the existing event analysis algorithms do not make full use of the structure information on social network of microblogs, this paper proposes a microblog online event analysis algorithm based on incremental topic model. This algorithm designs a reasonable incremental process to preserve the existing training information, and gives an adaptive asymmetric learning mechanism to integrate the content and user relationship of new microblogs. Experimental results show that this algorithm leads to more balanced and comprehensive improvement for online event detection in near real-time scenarios.
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Computer Engineering. 2013, 39(3): 197-202,208. https://doi.org/10.3969/j.issn.1000-3428.2013.03.039In order to improve the background subgraph classification accuracy of existing background outlier detection algorithm, this paper proposes a background outlier detection algorithm based on K-way spectral clustering. This paper establishes the diagram model, does the K-way partition to make it have explanatory significance for background subgraph, and gets the outliers from the background subgraph. Experimental results show that the accuracy of this algorithm is improved by 50% at H index and is reduced by 70% at VI index. There is no change with the structure of graph. So it cannot produce the problem of losting important information.
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Computer Engineering. 2013, 39(3): 203-208. https://doi.org/10.3969/j.issn.1000-3428.2013.03.040Aiming at the problem of self-localization for the mobile robot, a new infrared landmark localization module of embedded mobile robot is proposed. The module uses a single matrix initial calibration algorithm and camera initial calibration method to calibrate the camera before the process of localization. Experimental result shows that this module is effective on the embedded processors, and the precision of position localization is in the range of millimeter, the angle localization is less than 6°.
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Computer Engineering. 2013, 39(3): 209-212. https://doi.org/10.3969/j.issn.1000-3428.2013.03.041This paper introduces the Simulated Harmonic Oscillator(SHO) algorithm, and analyses the global convergence of it. Process of SHO is divided into three basic operations, such as generating new solution, amending current solution, composing new solution sets, and mapping these changes of state into three stochastic matrixs. Using limited Markov chain theoretics to analyse the matrix of state changing, it is proved that when the running time goes infinity, SHO with keeping excellent answer can keep the best global solution convergent.
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Computer Engineering. 2013, 39(3): 213-217,222. https://doi.org/10.3969/j.issn.1000-3428.2013.03.042To solve the difficulty when objects undergo large pose change most existed visual tracking algorithms tend to drift away the target or even fail in tracking it, this paper proposes a Multiple Instance Learning(MIL) target tracking algorithm based on sparse representation. This algorithm is to model the appearance of an object by local sparse codes which are formed as training data for the MIL framework. Within MIL framework, the proposed algorithm learns the sparse codes for a MIL classifier. Results from the trained classifier are input into a particle filter framework to sequentially estimate the target state over time for visual tracking. Experimental results show that this algorithm stability is good, and can decrease the center position error rate by 30% compared with IVT algorithm, L1 algorithm, MIL tracking algorithm.
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Computer Engineering. 2013, 39(3): 218-222. https://doi.org/10.3969/j.issn.1000-3428.2013.03.043In order to improve the efficiency of task schedule and data transmission about the massive data of weather bureau under limited bandwidth, this paper proposes a meteorological data grid task schedule algorithm based on Particle Swarm Optimization(PSO) improved algorithm. It gives the conception of Replica Domain(RD), makes combination of PSO algorithm, and designs task schedule model and the objective functions which conform to the meteorological data grid environment. Simulation results show that the finishing scheduling time of this algorithm is less than Genetic Algorithm(GA) and end search algorithm, its convergence speed is faster than Discrete Particle Swarm Optimization(DPSO) algorithm, and is more stable.
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Computer Engineering. 2013, 39(3): 223-228,235. https://doi.org/10.3969/j.issn.1000-3428.2013.03.044Aiming at the inaccuracy of structural similarity and semantic similarity in the process of measuring semantic similarity between objects represented by Resource Description Framework(RDF) graph, a method named Structure and Semantics(SAS) is proposed, which calculates semantic similarity of concept nodes by combining improved semantic distance formulas based on the network model and weight measure mechanism based on the information quantity model, and perfects the algorithm of semantic similarity of RDF graphs. SAS reflects the influence of structure, depth, density in semantic similarity of RDF graphs. Prototype system is designed and realized. Results show that the method can effectively guarantee the RDF graph is consistent with the reality.
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Computer Engineering. 2013, 39(3): 229-235. https://doi.org/10.3969/j.issn.1000-3428.2013.03.045There is a problem of loss decision information resulting from unsuitable reference points and unreasonable discount belief functions in the traditional DS/AHP method for group decision making. In order to solve above problem, a subjective information fusion model is constructed to integrate preferences of decision subjects on a specific attribute, in terms of mutually exclusive alternative groups induced and judged by decision subjects and relative preference information with seven-scale. After that, with reference to the transformation from knowledge matrix to Basic Probability Assignment(BPA) as well as information fusion thoughts by utilizing Dempster combination rule in traditional method, the proposed decision procedures are introduced to fuse evidence information on all of attributes. A simulation case shows the proposed method is scientific, applicable and feasible. The total degree of difference between its Pignistic probability and standard result is small.
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Computer Engineering. 2013, 39(3): 236-240. https://doi.org/10.3969/j.issn.1000-3428.2013.03.046By studying the technology of automatic summarization, this paper considers the event as a basic semantic unit for narrative texts, and presents a new event-based method for automatic summarization in multiple topics text. This method utilizes events and the relationship between events to build event-network text representation model, and uses the algorithm of community detection to solve the problem of sub-event topic partition. Experimental results show that this method extracts a summary of higher precision, recall and F vaule, and better summarizes the content of the text.
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Computer Engineering. 2013, 39(3): 241-244. https://doi.org/10.3969/j.issn.1000-3428.2013.03.047Aiming at the problem of the weak ability of the 3-D transform to sparsely represent the true-image data in Block Matching 3D(BM3D) algorithm, an improved algorithm of image denoising by sparse BM3D is proposed. This paper uses shape-adaptive image patches(neighborhoods) replacing square windows image block. Shape-adaptive image patches by 3-D transform processing are PCA transformed. Experimental results show that the proposed method can efficiently denoise the Gaussian noise and improve the PSNR and SSIM of image, especially in preserving image details and introducing very few artifacts.
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Computer Engineering. 2013, 39(3): 245-249,253. https://doi.org/10.3969/j.issn.1000-3428.2013.03.048A lossy hyperspectral images compression algorithm based on Discrete Wavelet Transform(DWT) and Independent Component Analysis(ICA) is presented. Maximum Noise Fraction(MNF) method and Maximum Likelihood Estimation(MLE) are used to estimate dimensionality of original hyperspectral data. Based on the result of dimensionality estimation, ICA and DWT are respectively used in spectral and space direction. Set Partitioning In Hierarchical Trees(SPIHT) algorithm and arithmetic coding are respectively applied to the transformation coefficient, achieving quantify and entropy coding. Experimental results on Airborne Visible/Infrared Imaging Spectrometer(AVIRIS) 220 bands hyperspectral data show that the proposed method achieves higher compression ratio and more strong analysis capability than comparative algorithms.
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Computer Engineering. 2013, 39(3): 250-253. https://doi.org/10.3969/j.issn.1000-3428.2013.03.049The traditional algorithm is inefficient in 3D faces point-to-point correspondence. To address this problem, an improved Active Shape Model(ASM)-based automatic 3D faces correspondence algorithm is proposed. The algorithm rapidly locates a 2D face. And accurately position the feature points in the texture maps of 3D models, which are generated by unwrapping 3D faces to 2D space. Feature location information is used to patch the unwrapping map. The resample algorithm based on the planer template is used to automatically achieve the pixel-wise correspondence between 3D faces. Experimental results show that the algorithm not only can improve the operation rate, but also the normalized results obtained remains 99% shape similarity with the original data.
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Computer Engineering. 2013, 39(3): 254-257. https://doi.org/10.3969/j.issn.1000-3428.2013.03.050In order to grasp the shape of mountains, this paper is focus on the macro terrain features, and proposes a method of extracting mountain lines through vectorization technique. It presents the extraction method considering the mountains line consists of some ridge-lines segments, which fit the features of mountains. It is aiming at the vectorization of ridge-lines and the design rule of extraction. Experimental results show that the method is reasonable and accord with landscape cognition.
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Computer Engineering. 2013, 39(3): 258-263. https://doi.org/10.3969/j.issn.1000-3428.2013.03.051In order to bridge the semantic gap, a multi-modal image retrieval system is proposed based on semantic learning. The system combines three query modes to retrieval images. The paradigm of query by visual feature ranks images by feature extraction and similarity matching; The paradigm of query by label is based on automatic image annotation, but its generalization ability is not good outside the semantic space; The paradigm of Query by Semantic Example(QBSE) can overcome the problem to a great extent. It makes the retrieval more agreeable with human perception by executing the query in either explicit or implicit semantic space. Experimental results show that the paradigm of query by semantic example has higher precision and recall rate than image retrieval based on the texture feature.
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Computer Engineering. 2013, 39(3): 264-266,271. https://doi.org/10.3969/j.issn.1000-3428.2013.03.052This paper aims at the selection of residual-repaired threshold in image super-resolution reconstruction based on Projection Onto Convex Sets(POCS) and improves it. Changing the mode of fixed residual-repaired threshold in the traditional POCS algorithm, this paper introduces a prior information about low resolution image definition into POCS to control the threshold by characterization parameter of image relative definition and realizes the dynamic threshold selection in the entire progress of reconstruction. Experimental results show that the improved algorithm has very good effect on improving the clarity of the reconstructed image and PSNR.
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Electrocardiosignal Baseline Wander Denoising Algorithm Based on Digital Filtering in Wavelet DomainComputer Engineering. 2013, 39(3): 267-271. https://doi.org/10.3969/j.issn.1000-3428.2013.03.053To solve the problem of processing removal noise of electrocardiosignal Baseline Wander(BW), this paper presents a denoising algorithm based on digital filtering in wavelet domain. The electrocardiosignal is decomposited with the lifting wavelet, then processed through the digital high-pass filter on the highest level of scale coefficients and reconstructed with the removed baseline wander. Based on the noisy electrocardiosignal data in the MIT/BIH database, simulation studies on the proposed algorithm are done. Compared with traditional methods, simulation results show that the proposed algorithm achieves a better balance between computational complexity and performance. MSE of the proposed algorithm is only 0.001 8 in 10 dB SNR condition.
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Computer Engineering. 2013, 39(3): 272-274,278. https://doi.org/10.3969/j.issn.1000-3428.2013.03.054The single event upset is existed in classical Dual Interlocked Cell(DICE) master-slave flip-flop caused by inverse drive. It is solved by inserting the buffer into master-slave to block reverse drive path. A ground heavy ion test is taken on a DICE harden chip. Test results show that the improved DICE flip-flop not only eliminates the single event function interrupt, but also greatly reduces the single event upset.
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Computer Engineering. 2013, 39(3): 275-278. https://doi.org/10.3969/j.issn.1000-3428.2013.03.055For the requirements of high-capacity, high-bandwidth, expandability of storage devices in spacecraft telemetry, a new storage architecture of solid-state recorder is presented based on improving the access speed of the large capacity memory storage. Meanwhile, a mature technology of line parallel storage is applied into the design of the storage module, and the access speed of the storage structure is analyzed. The highest speed of storage is about 300 MB/s, and the high reliability of the storage architecture is confirmed through the fly experiment.
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Computer Engineering. 2013, 39(3): 279-284. https://doi.org/10.3969/j.issn.1000-3428.2013.03.056Remote fire detection system based on TMS320DM642 microprocessor and DSP/BIOS real-time operating system is implemented for resolving the probleme of detection shorter distance, higher misinformation and lower reliability of sensor technology in large space. Firstly a series of frames are pre-processed in RGB space. Then suspected target areas are extracted depending on the flickering feature and fuzzy clustering analysis. The features, such as fire correlation, rate of area growth and circularity are regarded recognization criterion of fire. DSP/BIOS and RF5 based-system is designed and tested to illuminate the scheme feasibility. Experimental result shows that the proposed system improves the accuracy and speed of image fire detection in a variety of large space, and it can meet the needs of remote fire detection.
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Computer Engineering. 2013, 39(3): 285-288,299. https://doi.org/10.3969/j.issn.1000-3428.2013.03.057Considering the apron service vehicle operation behavior problem which has stochastic characteristics, this paper analyzes the struction of service vehicle Agent. Thanks to Agent-oriented stochastic Petri net technology, the apron service vehicle Agent operation behavior model is established, and the optimization method for service vehicles run average service time is given. Using CPN tools to simulate and verify the model. The results show that the model can optimize the average service time of the service vehicle Agent.
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Computer Engineering. 2013, 39(3): 289-294. https://doi.org/10.3969/j.issn.1000-3428.2013.03.058Aiming the problem that robust fault detection of Networked Control System(NCS) with time-varying sampling period and time delay, the uncertainties of time-varying sampling period and time delay in NCS are converted into the uncertainties of the parameter matrix by the real Jordan form approximation, and a discrete-time model with parameters uncertainties lying inside a polytypic framework is proposed. The residual generator is constructed and the problem of fault detection can be converted into the design of the Robust Fault Detection Filter(RFDF). The sufficient conditions for existence of the RFDF are established in terms of linear matrix inequalities. Simulation result shows the filter can repeat the fault signal well and it is robust for the disturbance and the uncertain sampling interval and time delay.
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Computer Engineering. 2013, 39(3): 295-299. https://doi.org/10.3969/j.issn.1000-3428.2013.03.059When OpenMP programs are extended to heterogeneous multi-core architectures, the remote memory access may make the memory access cost increase and program performance decrease. In order to solve this problem, this paper introduces a data distribution clause with array partition information to manage data layout in the heterogeneous multi-core memory system. Furthermore, it proposes a new algorithm based on the parallel loop recognition and array reference pattern analysis, so as to realize the automatic generation of such clauses. Experimental results demonstrate that the automatic generated OpenMP programs with data distribution clauses have relatively good data locality and achieve significant performance increase on heterogeneous multi-core systems.
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Computer Engineering. 2013, 39(3): 300-305,310. https://doi.org/10.3969/j.issn.1000-3428.2013.03.060To improve the efficiency of the video stabilization system, an algorithm based on Harris and modified Hu-moments is proposed. In this algorithm, Harris corners of each frame are detected as the feature-points, and the modified Hu-moments in the corner-centered neighbourhood are calculated to be the feature-vectors corresponding to the feature-points. The affine transformation model is used in the motion estimation between the frames. The motion traces of each direction are got. A stabilized video sequence is generated after compensation being exerted on the frames. Experimental results show that when the images are rotated or slightly zoomed, and the compute complexity is greatly reduced in the processing of feature-matching with an ideal result.
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Computer Engineering. 2013, 39(3): 306-310. https://doi.org/10.3969/j.issn.1000-3428.2013.03.061Due to the problems such as complex calculations and poor efficiency of the sensor pattern noise as the inherent fingerprint of mobile phone cameras when it is used in digital images origin forensics, a new method which based on large components of sensor pattern noise for mobile phone camera is proposed. According to the optical response characteristics and special influence of the light sensitive points, it makes up large components of imaging sensor pattern noise mainly for mobile camera origin detection. Experimental results show that, compared with the conventional image source detection method based on the pattern noise, the proposed method can not only identify the source of mobile phone camera images effectively, but also decrease the computational load for detection.
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Computer Engineering. 2013, 39(3): 311-315. https://doi.org/10.3969/j.issn.1000-3428.2013.03.062Independent Component Analysis with Reference(ICA-R) can extract only desired source signal from mixtures of all source signals by incorporating prior information into the learning algorithm as reference signal. The rule of voice signal transmission and Bessel function expansion can describe voice signals. This paper applies Independent Component Analysis with Reference(ICA-R) to extract a target voice signal from mixtures of all source signals by constructing a proper reference signal with Bessel function expansion, computer simulation results and performance analysis demonstrate the method can get better voice enhancement effect under noise interference situation.
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Computer Engineering. 2013, 39(3): 316-320. https://doi.org/10.3969/j.issn.1000-3428.2013.03.063Comparing the differences of Guangdong’s Certification Authority(CA) and Hong Kong’s CA in Certificate Practice Statement(CPS) and Certificate Policy(CP), this paper analyses the current cross-domain Public Key Infrastructure(PKI) trust framework, resolves the problem about mutual authentication in the case of the policies and regulations of the two places not fully standardized by transferring the digital signature, and realizes the cross-border authentication by using Certificate Trust List(CTL) trust model. As practice shows, the scheme is suitable for mutual recognition of point-to-point CA and lays the foundations for the mutual authentication between China and other countries or areas such as Shanghai Cooperation Organization, Association of Southeast Asian Nations and Australia.
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