20 June 2012, Volume 38 Issue 12
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Computer Engineering. 2012, 38(12): 1-4. https://doi.org/10.3969/j.issn.1000-3428.2012.12.001
This paper proposes an automatic method to compute the exposure time for space array Charge Coupled Device(CCD) based on image quality. An imaging simulation for geostationary satellite array CCD camera is designed. The range of normal exposure time is calculated according to the modified exposure estimation method. The exact exposure time can be automatically obtained based on selected image quality evaluation indexes for any given location and time. Experimental results confirm that the proposed algorithm is effective and leads to improvement in photography to obtain high quality remote sensing images.
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Computer Engineering. 2012, 38(12): 5-8. https://doi.org/10.3969/j.issn.1000-3428.2012.12.002
The gray level difference between the pedestrians and environment is small in infrared images, and it is easy to appear the problem of fault segmentation while segmenting. This paper proposes a dual-threshold segmentation method for infrared pedestrian. The global threshold of the image is computed by using the statistical variance, and it is used for a preliminary segmentation. A cross-shaped sliding window is introduced to scan the image. The local threshold of each pixel in the initial segmentation objective area is computed by using statistical variance. By means of the classified formula, the pixel can be classified into objects or the background area. The binary image is obtained. Experiments show that this method improves the segmentation accuracy, and has good performance on pedestrian segmentation.
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Computer Engineering. 2012, 38(12): 9-12. https://doi.org/10.3969/j.issn.1000-3428.2012.12.003
This paper studies the optimal information rate of perfect secret sharing schemes of a type of access structures on seven participants. Based on the relationship between these access structures and their connected graphs, 111 connected graphs corresponding to these access structures are given. The exact values of the optimal information rate of 91 access structures based on graphs are computed and the secret sharing schemes attaining the optimal information rate are discussed in Table 1, where the upper and lower bounds on the information rate of the rest 20 are also calculated. The upper bound on the information rate of connected graphs on seven vertices is theoretically proved.
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Computer Engineering. 2012, 38(12): 13-16. https://doi.org/10.3969/j.issn.1000-3428.2012.12.004
Through the analysis of the Distributed Denial of Service(DDoS) attack characteristics and the entropy changes of data flow five-tuple during the attacks, this paper proposes a detection model based on data Flow Struct Stability(FSS). This method through AR autoregression model to estimate multi-dimensional characteristic parameter of FSS time series, then classifies Support Vector Machine(SVM) with sample training into several categories and uses these results to identify the attacks. Experiments show that the model has high detection quality.
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Computer Engineering. 2012, 38(12): 17-21. https://doi.org/10.3969/j.issn.1000-3428.2012.12.005
The time complexity of the Parzen Window(PW) based Mean Shift Spectral Clustering(MSSC) algorithm is not less than O(N2), which means that it is impractical for medical image segmentation. In is paper, the problem of heavy time cost of original MSSC is solved by using two strategies of data condensation: reduced set density estimator and random sampling from every attraction basin, and the novel Data Condensation Based Spectral Clustering(DCBSC) algorithm is proposed. Compared with MSSC, the time cost of DCBSC is decreased effectively, and the practicability of DCBSC for medical image segmentation is improved accordingly.
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Computer Engineering. 2012, 38(12): 22-25. https://doi.org/10.3969/j.issn.1000-3428.2012.12.006
To solve the difficulty of identifying encrypted traffic, this paper proposes a fast network traffic identification method, which applies traffic payload signatures extraction instead of the deep analysis of full-payload data. This method uses 256-dimensional vector to describe the frequency of the packet payload 256 ASCII bytes occur. It extracts payload signatures based on the mean and variance of the quantitative traffic payload. Then it classifies the network traffic into different applications by using a decision tree model. Experimental results show the proposed method can accurately classify the common encrypted network traffic and detect traffic from some malicious attacks.
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Computer Engineering. 2012, 38(12): 26-28. https://doi.org/10.3969/j.issn.1000-3428.2012.12.007The complexity of higher order correlation function increases exponentially with the growth of the dimension. An improved high-order correlation function calculation method is presented in this paper. A new pruning research algorithm based on the KDC-tree data structure is designed. The implementation of three points correlation function is given, and it is accelerated with parallel technology to optimize the calculation of high-order correlation function. Experimental results validate the correctness and efficiency of this method.
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Computer Engineering. 2012, 38(12): 29-31. https://doi.org/10.3969/j.issn.1000-3428.2012.12.008In order to update and query eXtensible Markup Language(XML) data effectively, a Fraction and Prefix Encoding Scheme(FPES) is proposed. It introduces the fractions into prefix encoding scheme LSDX. FPES makes good use of the fraction characteristics of insertion, and unlimited fractions can be inserted between any two fractions to support the infinite update of node data. It supports the representation of ancestor-descendant relationship, parent-children relationship and sibling relationship between any two nodes. It avoids re-encoding completely. Experimental results show that FPES improves the query efficiency compared with LSDX. FPES spends less time in encoding and inserting nodes compared with fraction encoding.
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Computer Engineering. 2012, 38(12): 32-35. https://doi.org/10.3969/j.issn.1000-3428.2012.12.009In order to detect both Additive Outliers(AO) and Innovation Outliers(IO) in time series, this paper improves the linear prediction of time series, proposes a Distance Factor Recursive Least Square(DF-RLS) algorithm. It combines DF-RLS with distance-based outlier detection method, proposes a time series outlier detection method based on distance and DF-RLS, named DDR-OD. Experimental results show that the DDR-OD is an effective method for time series outlier detection.
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Computer Engineering. 2012, 38(12): 36-38. https://doi.org/10.3969/j.issn.1000-3428.2012.12.010After analyzing the topological properties of community in bipartite networks, a new community algorithm based on the idea of core and outer layers is proposed for resolving the problems that some community algorithms on bipartite networks can only classify one type of nodes or depend on additional parameters. This algorithm completely depends on the original network topology and it allows overlapping between communities. Experimental results show that this algorithm can exactly detect the number of communities and community structure of two types of nodes in realistic networks without additional parameters.
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Computer Engineering. 2012, 38(12): 39-41. https://doi.org/10.3969/j.issn.1000-3428.2012.12.011In order to solve the problem that the existed incremental mining algorithms need to mine the sequence database once again, and reduce the time and space consumption generated by repeatly running mining algorithm in the process of the sequential pattern mining, this paper proposes an efficient incremental mining algorithm of sequential patterns. It uses the frequent sequence tree as the storage structure of the algorithm. When the sequence database is updated and the minimum support is changed, it updates the frequent sequence tree by performing the update operation. It finds all the sequential patterns through using depth-first search strategy to traverse the frequent sequence tree. Experimental results show that the algorithm outperforms IncSpan and PrefixSpan in time cost.
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Computer Engineering. 2012, 38(12): 42-44. https://doi.org/10.3969/j.issn.1000-3428.2012.12.012By anglicizing the limitations of existing evidence theory method for Deep Web interface integration, a Deep Web pattern matching method based on concept word and semantic heterogeneity model is proposed. The method preprocesses pattern through extracting concept word, discriminates and combines group attributes to convert m︰n complex matching into 1︰1 simple matching for improving implement efficiency. By introducing instance into semantic heterogeneity model, the problem of mining semantic heterogeneity synonymy attributes is resolved by computing, synthetic evaluating, and selecting similarity values of attribute features. Experimental results indicate that compared with evidence theory method, the efficiency and accuracy of the method is improved obviously.
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Computer Engineering. 2012, 38(12): 45-47. https://doi.org/10.3969/j.issn.1000-3428.2012.12.013The semantics of Ontology Web Language for Services(OWL-S) process model is not complete, which makes it difficult to carry out analysis and verification by machine. To solve this problem, this paper proposes a formalization method of OWL-S process model. It describes the atomic processes with their inputs, outputs, preconditions and effects and composite processes with their control construct, then the first-order dynamic logic semantics for process model is obtained. Example result validates the effectiveness of this method.
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Computer Engineering. 2012, 38(12): 48-51. https://doi.org/10.3969/j.issn.1000-3428.2012.12.014This paper analyzes the problems in the current block-level Continuous Data Protection(CDP), a CDP mechanism based on increment backup server is proposed. On the basis of TRAP-4, this paper improves the generation mode of log chain and compression methods of related data, validates the correctness of the log link periodically. The main work of continuous data protection is migrated to the increment backup server, then the workload of server system is alleviated effectively. Experimental results prove the validity of the mechanism.
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Computer Engineering. 2012, 38(12): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2012.12.015This paper discusses the difference between digital evidence and traditional physical evidence, analyzes the requirements of digital evidence management, proposes a management method, which uses Digital Evidence Bag(DEB) format as the universal container of digital evidence, designs XML signature link which maintains the chain of custody and makes the process traceable. A system prototype is designed which proves the feasibility of the method.
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Computer Engineering. 2012, 38(12): 55-58. https://doi.org/10.3969/j.issn.1000-3428.2012.12.016Based on the classical BIDE algorithm, this paper presents a multi-core parallel closed sequential patterns mining parallel algorithm, MT_BIDE. Through pruning before frequent sequential patterns expansion and reassigning them and their pseudo-projected datasets during the expansion process, MT_BIDE achieves the workload balancing which is always influenced by different calculation of different threads mining closed sequential patterns. Experimental results show that the algorithm has higher operating efficiency and speedup ratio.
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Computer Engineering. 2012, 38(12): 59-61. https://doi.org/10.3969/j.issn.1000-3428.2012.12.017This paper analyzes the information organization requirement of agriculture model, presents a generation method of Topic Map(TM) for agriculture model components. By extracting meta-data information of model components, and using XML Topic Map(XTM) notation, the Attribute Meta Topic Maps(AMTM) document are generated. With the support of instantiation and reflection technology, it builds the Local Atomic Topic Map(LATM) documents for specific model component. By using the character matching algorithm of topic information, this paper confuses the Meta Topic Map(MTM) of same type models, and generates the Global Atomic Topic Map(GATM) documents for agriculture model components. By generating top maps for crop development stage model components, the effectiveness of this method is verified.
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Computer Engineering. 2012, 38(12): 62-65. https://doi.org/10.3969/j.issn.1000-3428.2012.12.018In order to solve the problems of tight coupling, centralization and closure in the Automatic Test System(ATS) software platform architecture, this paper builds service-oriented ATS software platform architecture by layered pattern. With Kruchten multi-views method, the main bodies involved in the serviced-oriented ATS software platform are analyzed. The platform’s composition and running mechanism are discussed from diverse functional aspects such as organization and function. The main view of ATS software platform architecture is given. Application results show that this software platform architecture has the features of loose coupling, stretch and easy to integrate, and it can solve the problems of portability, instrument interchange-ability and information sharing of test procedures set in heterogeneous platform.
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Computer Engineering. 2012, 38(12): 66-68. https://doi.org/10.3969/j.issn.1000-3428.2012.12.019This paper presents a new communication model——Irregular Communication Model(IRRE) based on continuous percolation theory. The model maintains the lower neighbour node number at a shorter radius to ensure network sparseness, and prolongs some topology sides so as to enhance network connectivity, which can satisfy network topology connectivity and sparseness requirements. The contradiction of network topology connectivity and sparseness is solved satisfactorily. Simulation results show that connectivity and sparseness of IRRE are better than that of UDG.
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Computer Engineering. 2012, 38(12): 69-71. https://doi.org/10.3969/j.issn.1000-3428.2012.12.020According to the analysis of the random access process, considering that TD-LTE system random access preamble choice and assignment plan, this paper proposes a kind of control algorithm based on the priority level of the random access preamble selectivity. By increasing the preamble based on the priority level, the dedicated users can use this priority level. This algorithm can reduce the system broadcast resources and adapt scenes of different call arrive rate. Simulation result indicates that this algorithm can raise the access success ratio of the different load.
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Computer Engineering. 2012, 38(12): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2012.12.021Aiming at the problem of current traffic identification method limited by service port, protocol signatures and traffic encryption, this paper proposes a new traffic identification method based on multi-scale wavelet spectrum. The new method is able to achieve the identification of different network traffic by performing clustering analysis of K-means algorithm over the different scales wavelet spectrum coefficients that are inferred from the raw traffic by using Discrete Wavelet Transform(DWT). Experimental result shows that it has accurate identification results.
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Computer Engineering. 2012, 38(12): 75-78. https://doi.org/10.3969/j.issn.1000-3428.2012.12.022Binary Exponential Back-off(BEB) protocol causes these problems of channel utilization and fairness in jam states, it does not fit to multimedia transmission. Meanwhile BEB improved algorithm lacks the control to wireless channel dynamic states. Aiming at these problems, this paper proposes a priority-based slow start back-off algorithm. This algorithm provides a solution to the problems of priority crosstalk, supports WMSN, and provides better adaptability to load traffic. Simulation results show that compared with BEB, the back-off algorithm reduces 25% in collision rate and 10% in saturation delay, and keeps the same performance in saturation throughput.
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Computer Engineering. 2012, 38(12): 79-81. https://doi.org/10.3969/j.issn.1000-3428.2012.12.023Aiming at the problems that the uneven loads and the failure of single point happen to Object Naming Service(ONS) system when mass data in Internet of Things(IOT) need to be processed, ONS model based on two-layer P2P structure is proposed. ONS peer is organized into two different P2P networks according to two different ONS: local ONS and root ONS. The process of the information resolution in the model is described and the model is analyzed. Experimental results show that the amount of average response time is less compared with other models and the effect of load balance is better. Although the scale of IOT increases largely, the related data can be processed in time.
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Computer Engineering. 2012, 38(12): 82-85. https://doi.org/10.3969/j.issn.1000-3428.2012.12.024Aiming at the problem of premature convergence and poor local optimization ability of Genetic Algorithm(GA), this paper presents a Wireless Sensor Network(WSN) localization algorithm based on Gene Expression Programming(GEP). The sampling method is used to estimate the initial position of the node, followed by the initial position is refined by GEP, the encoding mode and unique genetic operator of GEP have more advantages in the process of parameters discovery. Experimental results show that the algorithm is better than traditional algorithm in optimization ability, positioning precision, and convergence rate.
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Computer Engineering. 2012, 38(12): 86-88. https://doi.org/10.3969/j.issn.1000-3428.2012.12.025Because the lifetime of Wireless Sensor Network(WSN) is restricted by the energy of nodes, this paper gives a WSN protocol for the environmental monitoring application, which uses a reservation system of temporary virtual circuit. In order to achieve the goal without conflicts, the data transmission is started and controlled by the control center which is characterized by the low consumption and high stabilization. By releasing awakening time schedules, the control center can adjust the duty ratio at any moment to decrease energy consumption of node. By using this protocol, node energy consumption is reduced while network lifespan is prolonged.
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Computer Engineering. 2012, 38(12): 89-91. https://doi.org/10.3969/j.issn.1000-3428.2012.12.026Traditional Ad Hoc networks transmit data with fixed maximum power, this working mode seriously affects the node and the network’s lifetime which is limited by the energy stored in mobile node. To address the issue, this paper proposes to observe the linear change of Signal to Interference Ratio(SIR) of receiving node to calculate the required transmitting power of sending node, so as to dynamically adjust the transmitting power. Simulation results show that this method can effectively reduce the energy loss of nodes and increase the network lifetime.
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Computer Engineering. 2012, 38(12): 92-94. https://doi.org/10.3969/j.issn.1000-3428.2012.12.027Aiming at the low rate of intrusion detection and the slow detection speed of intrusion detection method based on Support Vector Machine(SVM), this paper proposes a new method named Boundary-Incremental Support Vector Machine(B-ISVM). The boundary areas are identified and samples are screened for training to construct the initial classification hyperplane. The support vector is extracted according to screening factor. And the construction of the incremental SVM classifier is completed through incremental learning based on KKT conditions. Experimental results show that the method can achieve higher rate of intrusion detection and faster detection speed, and it has better classification performance.
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Computer Engineering. 2012, 38(12): 95-98. https://doi.org/10.3969/j.issn.1000-3428.2012.12.028By combining Fractional Fourier Transform(FRFT) and chaotic cryptography, this paper proposes a new transform domain encryption algorithm——chaotic key modulating the FRFT rotation factor, which is used to achieve real-time encryption and decryption for voice signals. By adopting eigen decomposition Discrete FRFT(DFRFT) algorithm, the real-time encryption system has good reduction property in decryption process of the speech signal. Theoretical analysis and test results show that the algorithm has high security, and it is better than the simple chaotic encryption or simplex FRFT encryption method.
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Computer Engineering. 2012, 38(12): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2012.12.029By analyzing the collision of four S-boxes which are subkeys of Blow-CAST-Fish, this paper develops the differential characteristic of function F with non-zero inputxor and a zero outputxor, performs a differential cryptanalysis of the algorithm to recover the rest of the subkeys, and tests the proportion of weak keys which can produce the differential characteristic. Based on this, it succeeds in using the 6-round differential characteristic with the probability 2－61 under 2－12 of the total key space to attack 8-round Blow-CAST-Fish.
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Computer Engineering. 2012, 38(12): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2012.12.030In digital fingerprinting system based on Quantization Index Modulation(QIM), higher the value of quantization step size is, worse the detection performance is. To resolve this problem, an improved QIM-based fingerprinting scheme is proposed to improve the continuity of fingerprinting signal and enhance the collusion resistance of fingerprinting system before fingerprinting imbedding by adding a random dither signal to the host signal. Simulation results show that the improved fingerprinting system has better detection probability than traditional QIM-based fingerprinting system.
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Computer Engineering. 2012, 38(12): 105-109. https://doi.org/10.3969/j.issn.1000-3428.2012.12.031With the application of high-speed Internet, all packets can not be followed by detection in massive data. Abnormal attack traffic is hardly identified. Poisson Pareto Burst Process(PPBP) of Classic model is used to analyze self-similarity of network traffic. Flow size is divided into long and short for a stratified sampling algorithm, according to sampling ratio incremental based on flow arrival time. The method is applied in anomalous detection system based on snort, and simulation results show that it can effectively reduce range of abnormal attack data, and detect quickly and precisely.
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Computer Engineering. 2012, 38(12): 110-111. https://doi.org/10.3969/j.issn.1000-3428.2012.12.032In order to improve the classification effectiveness of Self-organizing feature Mapping(SOM) neural network, this paper designs a Supervised Self-organizing feature Mapping(SSOM) network, which adds output layer into the network structure based on input layer and competitive layer. According to different prediction category of input samples, SSOM selects different formula to adjust weights and train network. Through combinations of two weights, SSOM realizes the regression and statistic of the sample classes. Experiments on KDD CUP99 dataset show that SSOM has better classification ability and higher intrusion detection rate.
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Computer Engineering. 2012, 38(12): 112-114. https://doi.org/10.3969/j.issn.1000-3428.2012.12.033Most available Identity-based signature schemes require expensive bilinear pairing operation, which leads to inefficient signature algorithm. In order to solve the problem, this paper proposes a new identity-based lightweight signature scheme without bilinear pairings. It is provably secure, and can resist chosen message attack in the random oracle model. Theoretical analysis shows that compared with other schemes, new scheme has lower computation cost and communication overhead, so it is suitable for secure communication protocols of key management and secure routing.
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Computer Engineering. 2012, 38(12): 115-117. https://doi.org/10.3969/j.issn.1000-3428.2012.12.034Most integrity measurement technologies of trusted network systems make use of focuses on executable files. In order to solve the problem that integrity measurement can not guarantee the credibility of the script files, this paper designs a trusted network system based on network traffic characteristics. Besides executing the integrity measurement, the system also computes the network traffic statistic information to judge the integrity state of the endpoint, which can be used to detect security threats when executing scripts. The system is implemented on Linux, and application results show that the system can detect some script viruses quickly.
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Computer Engineering. 2012, 38(12): 118-121. https://doi.org/10.3969/j.issn.1000-3428.2012.12.035This paper designs a characteristic code locating algorithm by using block-by-block recovery method instead of replacement method and proposes an auto free-antivirus strategy based on different PE sections. Under the premise of maintaining the original functionality of software after being modified to avoid killing, the combination of the strategy and the improved multi-characteristic code, it uses the equivalent code replacement, shifting methods of string and import table functions to automatically remove and replace the characteristic codes in tempt to avoid killing by anti-virus software. Experimental results verify the effectiveness of the strategy.
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Computer Engineering. 2012, 38(12): 122-124. https://doi.org/10.3969/j.issn.1000-3428.2012.12.036A new hybrid Path Relinking(PR) algorithm is presented. The algorithm combining the solution construction mechanism of Greedy Randomized Adaptive Search Procedure(GRASP) into PR is designed. It considers both solution quality and diversification. The process of the path relinking phase is to introduce progressively attributes of the guiding solution into the initial solution to obtain the high quality solution as quickly as possible. Moreover, the algorithm adopts the dynamic updating strategy of the reference set to accelerate the convergence towards high-quality regions of the search space. Experimental results show that the method is very efficient and competitive compared with the best existing methods in terms of solution quality.
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Computer Engineering. 2012, 38(12): 125-128. https://doi.org/10.3969/j.issn.1000-3428.2012.12.037To handle the influences brought by the change of pose and expression, Scale Invariant Feature Transform(SIFT) descriptors, which is rotating and scale invariant, is applied to measure the similarity between corresponding sub-regions of two faces, and the probabilistic similarity models of the same or different faces under various deformations are built with Gaussian Mixture Model(GMM). Then, a probabilistic frame which is based on Bayesian formula is established to get the recognition results, combining with the weight of each sub-region which is decided by their peculiarities. Experimental results indicate that the proposed method outperforms the traditional SIFT-based method when the variation of the pose or expression is large.
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Computer Engineering. 2012, 38(12): 129-131. https://doi.org/10.3969/j.issn.1000-3428.2012.12.038This paper discusses a continuous speech recognition approach for the resource-deficient languages, such as Uyghur. This approach tries a seed acoustic model using small training speech materials and creates final acoustic model using a larger speech materials and its transcription text by leading seed model. HTK is used for training acoustic model, and palmkit is used for creating language model, and the open-source speech recognition software Julius is applied for continuous speech recognition. In the test, the speech data of 6 400 sentences uttered by 64 native Uyghur speakers is used for training acoustic model and 100 MB text materials and a dictionary of 60 000 words are used for creating 3-garm language model based class. Experimental results show the rate of 72.5% for the real time sound recognition compared with the recognition result of 68.3% by HTK tool only.
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Computer Engineering. 2012, 38(12): 132-135. https://doi.org/10.3969/j.issn.1000-3428.2012.12.039Because of the problems of Shuffled Frog Leaping Algorithm(SFLA) such as local optimality and slow convergence rate, an improved SFLA is presented. In this algorithm, frog population is initialized with opposition base learning to improve the quality of initial solution. Then the adaptive inertia weight is introduced to correct frog update strategy which can balance the global search and local search. Simulation results of experiments on the six classical function show that compared with the SFLA and ISFLA1, the new algorithm optimization ability can be stronger, the number of iterations less, the solution better, the suitable for high-dimensional optimization of complex functions more.
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Computer Engineering. 2012, 38(12): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2012.12.040It is difficult for traditional methods which are used to locate and segment 2D barcode area to serve the needs in complicated background. This paper proposes a FAST 2D-code region detection and location algorithm. It combines Max-Min method and Canny operator to filter out the noises of image. And it can prominent the characteristics of the target information needed. Projection method and morphology operation are applied to locate and segment barcode area. Experimental results indicate that the method is simple, fast, accurate and can meet the needs of practical application.
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Computer Engineering. 2012, 38(12): 139-142. https://doi.org/10.3969/j.issn.1000-3428.2012.12.041Interval-valued attribute reduction is the core problem in interval-valued information systems research. By introducing a kind of α maximal tolerance class, this paper defines the attribute dependency and conditional entropy among attributes in interval-valued information systems, and proposes two types of attribute importance measurement, which has inner attribute importance and outer attribute importance. A uniform heuristic attribute reduction algorithm is given. The validity of the algorithm is illustrated by some experiments and the effect of different level of similarity α for reduction is investigated as well.
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Computer Engineering. 2012, 38(12): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2012.12.042Since the State of Charge(SOC) of electric vehicles battery has the characters of nonlinearity concerned with multifactor, and precision forecasted is difficult to be satisfied by the common artificial neural networks. A novel battery SOC forecast modeling is established by Back Propagation(BP) neural network based on Particle Swarm Optimization(PSO) which is used to optimize the weight and threshold of neural network. For overcoming the shortcoming of PSO algorithm trapped in local optimum, chaotic variables are provided to initialize the position of particles and the algorithm is embedded to avoid massive particles. It is proved through the simulation that the battery SOC is estimated rapidly, precisely and stably by this method.
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Computer Engineering. 2012, 38(12): 146-148. https://doi.org/10.3969/j.issn.1000-3428.2012.12.043The fundamental principle of face recognition based on sparse representation is analyzed. When sparse representation algorithm based on Orthogonal Matching Pursuit(OMP) is adopted, the obtained sparse coefficient can be negative. To solve this problem, an improved orthogonal matching pursuit algorithm is presented. By directly limiting the sparse coefficient, the proposed method can reduce the amount of negative sparse coefficient and iterations. Meanwhile, face recognition is speeded up. Experiment on the ORL database show that the recognition rate of improved algorithm is 3% higher than the original one, and the most suitable iteration times is 7.
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Computer Engineering. 2012, 38(12): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2012.12.044For using harmony search algorithm to solve dynamic optimization problems, this paper proposes a Hybrid-coding Binary Harmony Search algorithm(HBHSA) based on hybrid double-coding method. Following, for comparing the performance of HBHSA, DS_BPSO, HBDE and PDGA, it uses them to solve Dynamic Bit-matching Problem(DBMP) and Time-varying Knapsack Problem(TVKP) respectively. The numerical results show that the dynamic search capability and ability of traced optimal solution nearly as same as DS_BPSO and HBDE, and robustness and universality are more superior.
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Computer Engineering. 2012, 38(12): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2012.12.045Support Vector Machine(SVM) is a popular statistical learning methods, but large-scale training of SVM is limited by hardware. This paper proposes a face image gender classification algorithm based on a cascade connection SVM, which filters the easily classified samples by pre-layer classifiers, and re-organizes the left tough samples to train the next SVM layer. Meanwhile, more samples are used, and the classifier has better recognition performance. Experimental results under the same hardware conditions show that only 70 000 samples can be contained one time to train one-layer SVM, while more than 120 000 samples are involved in four-layer SVM, the corresponding recognition rate is 96.6% to 98.4%.
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Computer Engineering. 2012, 38(12): 155-157. https://doi.org/10.3969/j.issn.1000-3428.2012.12.046The effectiveness of traditional feature selection method is not good when feature dimension is low. A new method based on variance is proposed to solve this problem. This approach can select class information words in order to maintain categorization accuracy and improve the performance of rare classes. This paper gives a comparative analysis between the new method and other traditional feature selection methods such as Document Frequency(DF), Information Gain(IG), Mutual Information(MI), Chi-square Statistics(CHI), etc. Experiment takes Rocchio as the evaluation classifier. Experimental results on TanCorpV1.0 corpora show that the new feature selection Variance Feature Selection Method(VFSM) outperforms the traditional ones when using macro-averaged-measures F1.
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Computer Engineering. 2012, 38(12): 158-161. https://doi.org/10.3969/j.issn.1000-3428.2012.12.047The target tracking algorithm of Mean shift with fixed window bandwidth can not trace an object effectively when the moving object size changes. To solve this problem, a two-step update algorithm of adaptive window bandwidth is proposed. The Mean shift algorithm is used to compute the center and the size of target, and then they are computed again by the algorithm based on background subtraction method in the Region of Interest(RoI). By comparing the two Bhattacharyya coefficients between two target regions with the target model, final tracking window is obtained by selecting the region which has larger Bhattacharyya coefficient. Experimental results show that the algorithm can adaptively confirm the tracking window when the size of target changes greatly, and decrease background color effect on the target feature extraction.
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Computer Engineering. 2012, 38(12): 162-164. https://doi.org/10.3969/j.issn.1000-3428.2012.12.048This paper proposes a method of designing feedforward neural network based on Dynamic Multi-group Differential Evolution(DMDE) algorithm, which is introduced into hierarchical structure theory, and divides population into multi-group individuals dynamically. The new algorithm reconstructs individual gene to achieve information sharing and exchanging between individuals. To overcome the problem of optimizing structure blindly and inefficiently, the control gene is updated by group fitness. Simulation suggests that DMDE algorithm can optimize the topology structure and weights of the feedforward neural network efficiently. Furthermore, the designed neural network has high generalization ability when applied in gain schedule control.
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Computer Engineering. 2012, 38(12): 165-168. https://doi.org/10.3969/j.issn.1000-3428.2012.12.049Using non-stationary multi-stage assignment penalty function to deal with the constrained conditions, a modified constrained optimization evolutionary algorithm is proposed. In the process of evolution, in order to ensure the population evenly distributed in the search space, the individuals generation based on good point set method is introduced into the evolutionary algorithm initial step. The offspring population individuals are generated by simplex crossover and diversity mutation operator to maintain the diversity of population. Six classic Benchmark problems are tested. Experimental results show that the proposed algorithm is an effective way for constrained optimization problems.
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Computer Engineering. 2012, 38(12): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2012.12.050With the rapid development of the Internet of Things(IOT) and Intelligent Transportation System(ITS), the Floating Car Data(FCD) and the Radio Frequency Identification(RFID) technology are proposed to build a fuzzy comprehensive evaluation model where data fusionof the bus FCD, taxi FCD and the RFID detection data are implemented. As a result, more accurate and reliable bus operational data is obtained. The method is verified through a case study of dynamic message signs in Ningbo, which are installed in bus station and forecast the arriving time of the next bus.
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Computer Engineering. 2012, 38(12): 172-175. https://doi.org/10.3969/j.issn.1000-3428.2012.12.051In order to circumvent the difficulty of pre-assigning a threshold to terminate the iterations in training traditional Radial Basis Function(RBF) network, a novel RBF network training algorithm is proposed. A global k-means clustering algorithm and empirical method are utilized to construct the candidate sets for centre and scales of regressors. At each regressor stage, the parameters of each term are selected by minimizing Leave One Out(LOO) criterion using orthogonal forward selection. Simulation results show that the new algorithm can be terminated fully automatically. Compared with the other RBF networks, this scheme is capable of producing sparser RBF network with much better generality.
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Computer Engineering. 2012, 38(12): 176-178. https://doi.org/10.3969/j.issn.1000-3428.2012.12.052Aiming at the problem of the one-sided and incomplete nature for the current concept similarity computation, this paper presents an improved concept semantic similarity computation method which is based on semantic distance. It spreads semantic distance from three sides of the information contained in directed edge, the directed edge type and concept density, turns semantic distance to semantic similarity. At the same time, this paper introduces the dissymmetry factor, and makes the last concept semantic similarity computation more exact. Comparing this method with information-based method, distance-based method and the human subjective judgment, result proves that this method is feasible and valid.
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Computer Engineering. 2012, 38(12): 179-181. https://doi.org/10.3969/j.issn.1000-3428.2012.12.053After comparing the advantage and weakness of the statistical methods and the rule methods, an automatic method for the recognition of Chinese personal name based on both Transformation-based Error-driven Learning(TBL) approach and HowNet is presented. Using label corpus, the contexts of the names are tagged with different roles according to their functions in the recognition of Chinese personal name, and distilling the instances labeled by role tagging, combined with the TBL method and HowNet to distill the fit regulation. Rules and instances are assembled together to recognize personal name in the texts. Experimental results show that the combined method is more effective in Chinese name identification with high precision, recall rate and F value.
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Computer Engineering. 2012, 38(12): 182-184. https://doi.org/10.3969/j.issn.1000-3428.2012.12.054The paper proposes a method of face detection combined color of skin with continuous AdaBoost algorithm. In order to establish skin color model, this paper takes advantage of semi-supervised strategy to guide skin color clustering, and it also proposes a new algorithm SKDK in the process of clustering. skin color model can be established by the probability statistics distribution characteristics of each pixel cluster. On this basis, mathematical morphology of knowledge is used to handle image and find face candidate, which is the input of continuous AdaBoost classifier for final face detection. Experimental results prove that face detection ability of the method is superior to that directly using continuous AdaBoost method for face detection especially in multi-face situation.
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Computer Engineering. 2012, 38(12): 185-187. https://doi.org/10.3969/j.issn.1000-3428.2012.12.055This paper proposes a L1-norm regularized Support Vector Machine(SVM) clustering algorithm. The proposed clustering algorithm can fulfill simultaneous clustering construction and feature selection. Primal and dual form of L1-norm regularized SVM clustering problem is introduced, and an algorithm that iterates coodinate-wise desent approach is adopted to solve difficult mixed integer programming. Experimental results on real datasets show that the predict accuracy of the presented algorithm is compared with L2-norm regularized SVM clustering algorithm, and can take feature selection.
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Computer Engineering. 2012, 38(12): 188-190. https://doi.org/10.3969/j.issn.1000-3428.2012.12.056This paper uses DNA computing to solve graph clustering, provides a new approach to analyze graph problems. In split-level clustering, it uses DNA strands to assign vertices and edges, constructs the minimum spanning tree and cuts branches whose length is longer than the threshold, and gets the clustering results. In agglomerative hierarchical clustering, DNA computing to the undirected Shortest Hamilton Path(SHP) problem is introduced, and the clustering results are gotten. Experimental results prove the feasibility of the algorithm.
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Computer Engineering. 2012, 38(12): 191-193. https://doi.org/10.3969/j.issn.1000-3428.2012.12.057According to the characteristic of building areas in Synthetic Aperture Radar(SAR) images, a method based on the level set is used to detect building areas and building targets. It uses the boundary feature based on exponential wavelet and texture feature based on variogram to build the energy criterion model, and then the evolutive curve is implemented by minimizing the energy criterion via variational level set approach to detect the building areas. Compared with the traditional energy criterion model based on the gray information, experimental results show that the proposed method is effective and can detect building areas of the large SAR image accurately.
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Computer Engineering. 2012, 38(12): 194-196. https://doi.org/10.3969/j.issn.1000-3428.2012.12.058Based on the sparse characteristic of image signal in Contourlet transform domain, the theory of image Contourlet transform is analyzed, and the image Compressive Sensing(CS) reconstruction method is proposed based on the Contourlet transform. Because the basis of Contourlet transform is not orthogonal strictly and can not construct orthogonal matrix, this paper proposes an image reconstruction method which is based on ameliorative gradient projection algorithm to improve the conventional reconstruct algorithm. The image reconstruction method which is based on ameliorative gradient projection algorithm can realize the high quality image reconstructed with low sampling rate. Experimental result shows that the proposed method has good robustness.
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Computer Engineering. 2012, 38(12): 197-200. https://doi.org/10.3969/j.issn.1000-3428.2012.12.059Considering the problem of the image retrieval method based on shape, this paper proposes a novel method for image retrieval based on feature points of contour of an interesting object. Mean Shift algorithm is applied to extract an interesting object, then the local maximum points of curvature of the object contour are calculated and the object is described with its eigenvector comprised of these feature points. An effective matching mechanism based distance between the eigenvectors of a retrieve object and a retrieved object is used to carry out matching or recognition between two objects. Experimental results show that the proposed method has a higher recall and precision.
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Computer Engineering. 2012, 38(12): 201-204. https://doi.org/10.3969/j.issn.1000-3428.2012.12.060In order to overcome the limitations in adaptivity of existing Graphics Processing Unit(GPU) terrain rendering method, based on the data structure of quadtree for terrain blocks, an adaptive terrain rendering method is proposed using synthetical Level of Detail(LOD) factor. The LOD evaluation function comprehensively considers three factors: the static blocks roughness error, the dynamic view-dependent error and the viewpoint moving speed influence. The vertex’s height value is smoothly geomorphed in the GPU Vertex Shader(VS) for eliminating the pops using the synthetical LOD factor. The skirts are used to avoid producing cracks. Experimental results show that the method has better adaptivity. It can obtain higher frame rates and GPU utilization ratio.
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Computer Engineering. 2012, 38(12): 205-207. https://doi.org/10.3969/j.issn.1000-3428.2012.12.061In chest CT images analysis, for the reasons of CT noise and long calculating time of 3D lung marking segmentation using Level-set, this paper proposes a method that combines 3D C-V Level-set model with multiple scales analysis to segment lung marking. According to the theory of wavelet transform, volume data of C-V model processing starts from the lowest scales to the highest scales step by step. Experimental result shows that the new method can reduce processing time drastically and weaken influence of noise.
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Computer Engineering. 2012, 38(12): 208-210. https://doi.org/10.3969/j.issn.1000-3428.2012.12.062FAST-9 detector can not be invariant to scale changes. Aiming at this problem, this paper proposes a fast image matching algorithm based on multi-scale FAST-9. Feature points are extracted from the constructed Gaussian scale space by the FAST-9 detector, and main orientation is assigned based on information from a circular region around the interest point. SURF descriptor is extracted by a constructed square region aligned to the selected orientation. The matching pairs are determined with the nearest neighbor distance matching method. Experimental results show that the proposed algorithm outperforms better than SURF and SIFT algorithm in speed.
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Computer Engineering. 2012, 38(12): 211-213. https://doi.org/10.3969/j.issn.1000-3428.2012.12.063In the system of image automatic annotation, the accuracy of low-level feature and senior semantic annotation is low. Aiming at this problem, combined with low visual features in automatic notation system and senior semantic feature in socialized annotation system, this paper proposes FAC algorithm based on image automatic and socialized annotation. It obtains several candidate annotations from automatic notation system, and users in the website flickr. It uses the image annotation recommending strategy to get recommending annotations. The final aggregate of label results are made full use of the semantic relations from the WordNet semantic dictionary. Experimental result shows that, compared with traditional automatic notation algorithm, the accuracy of FAC algorithm is higher than traditional semantic retrieval.
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Computer Engineering. 2012, 38(12): 214-217. https://doi.org/10.3969/j.issn.1000-3428.2012.12.064An extensible parallel decoding algorithm for TilePro64 multicore platform is proposed to improve the choice and partition of the parallel function module, optimize the speed of the parallel decoding. The algorithm organizes the function modules of the algorithm and divides them into several function groups. The algorithm assigns the function module dynamically according to the relationship among the data of the processors to optimize the efficiency of the parallel decoder. Experimental results indicate that the algorithm improves the efficiency and the parallelization, reduces the latency time, achieves a 25% performance increase of speedup compared to the traditional parallel algorithm.
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Computer Engineering. 2012, 38(12): 218-221. https://doi.org/10.3969/j.issn.1000-3428.2012.12.065This paper analyzes both the spatial and temporal interpolation methods and proposes an efficient new motion and texture adaptive de-interlacing algorithm based on the H.264 encoding. The picture is classified into three regions: motion region, static texture region and static smooth region based on the analysis of motion estimation, motion compensation and intra-prediction. Methods of ELA, VT and LA are used to do the region de-interlacing work. Experimental results show that the proposed algorithm works well in both motion and static pictures, it restrains the effects of line-crawling and fake-shadow brought by the probable bad motion detection effectively and provides better quality.
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Computer Engineering. 2012, 38(12): 222-224. https://doi.org/10.3969/j.issn.1000-3428.2012.12.066Aiming at the requirement that video decoder chips should be compatible with both AVS and H.264 video coding standard, a dual- mode variable length decoder is proposed. The reuse of barrel shifter and Exp-colomb decoder is adopted, and it uses combinational logic to look up table, optimizes and rebuilds code tables of AVS and H.264. The design is simulated and tested in ModelSim, synthesized and validated on the Field Programmable Gate Array(FPGA) chip. Result indicates that it can be applied to both AVS and H.264 standard, reduce the circuit size and complexity, and improve the efficiency of looking up table.
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Computer Engineering. 2012, 38(12): 225-227. https://doi.org/10.3969/j.issn.1000-3428.2012.12.067In the current, the structured P2P-based time-shifted streaming system exists the problems that the copy of scalability is bad and the maintenance costs are higher. For resolving the problems, a structured query model based on video block for time-shifted streaming is proposed. By the hierarchy divided according to the first video block in the cache of node and all video block in the cache registered, it makes the routing information reduced which layer node needs to maintain and the problem resolved which the copy of time-shifted streaming can not be fully found. Experimental results show that compared with other model, this model has a better cache hit ratio, better lookup performance and lower maintenance overhead.
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Computer Engineering. 2012, 38(12): 228-231. https://doi.org/10.3969/j.issn.1000-3428.2012.12.068To meet the avionics electronic system testability and reduce avionics electronic system test and maintenance costs, this paper designs a Built-in Test(BIT) system referring to ASAAC standard. BIT is defined as a capability provided by electronic system itself for the fault detection or isolation. As a Hierarchy design, it divides the BIT system into three levels, system level, subsystem level and module level, and makes a design in details containing software and hardware design for module level test. Test results show that the system can make the test combining with the health management and fault management of avionics electronic systems more closely. It meets technical indicators and greatly improves avionics electronic system reliability and testability.
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Computer Engineering. 2012, 38(12): 232-235. https://doi.org/10.3969/j.issn.1000-3428.2012.12.069Researching the application of embedded high-speed storage system, the shortage and limitation of traditional data storage are discussed, and a method of high-speed embedded data storage system based on SATA is put forward. The method builds SATA storage channel which meets SATA standard in Field Programmable Gate Array(FPGA), it implements SATA physical layer and link layer completely, and combines SATA transport layer and application layer to establish DMA module based on the demands of embedded storage application. The SATA storage channel storages data in SATA devices directly. Extending SATA storage channels can achieve the expansion of bandwidth and capacity of system. Experimental result shows that the method works well and achieves high-bandwidth and generality.
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Computer Engineering. 2012, 38(12): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2012.12.070Aiming at the problem that topography affects the signal coverage, a new method of analyzing DME/DME navigation signal coverage combined with the actual topography is proposed. This paper based on Digital Elevation Model(DEM), analyzes the signal coverage of single DME by using visual analysis theory. Combined with geographic information systems, it analyzes the DME/DME signal effective coverage of Beijing-Shanghai route. Simulation results show that the method can more accurately predict the DME/DME signal effective coverage and avoid potential security risks.
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Computer Engineering. 2012, 38(12): 239-242. https://doi.org/10.3969/j.issn.1000-3428.2012.12.071This paper presents an optimized and fine grained strategy LPDVFS(DVFS based on Linear Prediction) aiming at mobile operating systems based on Linux kernel. This strategy uses the linear prediction mechanism based on historical data to adjust the range and orientation of voltage and frequency. The parameters are obtained through regression method. Experimental results show that the optimized LPDVFS strategy can save 13.55% energy consumption compared with the default coarse grained frequency scaling strategy. The LPDVFS strategy can reach better power saving effect and enhance the cruising ability of mobile terminals.
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Computer Engineering. 2012, 38(12): 243-246. https://doi.org/10.3969/j.issn.1000-3428.2012.12.072Based on Wireless Sensor Network(WSN) and Geographic Information System(GIS) technology, an irrigation system that can flexibly use surface and ground water on well-canal combined irrigate area is designed. In order to improve the information management and water resource scientific utility, open source GIS(MapWindow) module and open source database software(MySQL) are chosen. The result of field operation shows that WSN has a good connection and strong resistance to interference, and the software system consists of server, database and client which can support multi-operating system. This system satisfies joint regulating water resources, remote wireless control and management for well-canal combined irrigated area.
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Computer Engineering. 2012, 38(12): 247-250. https://doi.org/10.3969/j.issn.1000-3428.2012.12.073This paper proposes an Audio and Video coding Standard(AVS) loop filter based on ping-pong parallel storage and ping-pong transposed matrix structure to improve AVS video system deblocking filtering speed. Two sets of memory storage are used for storing two adjacent macroblock. In current macroblock deblocking process, filtered macroblock is read and new macroblock is deposited at the same time in another storage. With two transpose matrix, horizontal boundaries are transposed continuously, which ensures the process of continuous horizontal boundaries filtering. Experimental result shows that the proposed design processing a macroblock only needs 122 clocks, and in 100 MHz working frequency, the design can satisfy the demand for 1 080 p high-definition decoding.
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Computer Engineering. 2012, 38(12): 251-254. https://doi.org/10.3969/j.issn.1000-3428.2012.12.074As to the problems of existing embedded mobile computing platform for low performance, and it has not high data security and reliability, this paper puts forward a solution based on cluster platform with the streamline, stability and easy expansion of Windows XP Embedded(XPE) operating system on the basis of the development of existing hardware. This system is based on the embedded X86 computer as the hardware foundation, a customized version of XPE as the system platform, with the cluster system solutions for the overall construction. Experimental results show that the solution is fully able to compensate for the increased demand for existing embedded mobile platform.
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Computer Engineering. 2012, 38(12): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2012.12.075In order to ensure vehicle safety on the highway, a real-time processing scheme of the millimeter-wave onboard forward collision avoidance radar system based on Digital Signal Processing(DSP) is proposed. A simplified two dimension Constant False Alarm Rate(CFAR) is used to decrease false alarm probability in target detection, MTD frequency domain matching is used to find positive sweep frequency spectrum and negative sweep frequency spectrum of the same target correctly. Experimental results show that the system can detect real-time distance and velocity of the forward target vehicle accurately, and it runs reliably.
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Computer Engineering. 2012, 38(12): 258-260. https://doi.org/10.3969/j.issn.1000-3428.2012.12.076In order to resolve the problems of poor safety, lacking control and communication techniques and low management level in current rural power grid, a kind of remote monitoring system of rural distribution district based on ZigBee Wireless Sensor Network(WSN) technology and simplified TCP/IP protocol technology is designed in this paper. On the basis of system overall design, implementation process of hardware and software of WSN, implementation process of software of front-end computer and backstage monitoring system is expressed in detail. Running effect indicates that this system can promote rural power grid’s automation standards and make it more reliable, more secure and more economical.
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Computer Engineering. 2012, 38(12): 261-264. https://doi.org/:10.3969/j.issn.1000-3428.2012.12.077Current similarity computation methods consider neither decisive function of key attributes, nor influence to case reasoning that is aroused by attribute value margin, a new case similarity computation method is proposed. It includes the innovations, such as, defining the attribute value margin and key attribute, designing new computation formulas and realizing method that computes whole case similarity after part similarity computing. Boolean function, entropy theory and composite combination strategy are used as math theory and analysis tools. And on precondition of having the same similarity computation efficiency, results prove that the new method can advance similarity computation resolving power ground.
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Computer Engineering. 2012, 38(12): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2012.12.078This paper gives a comprehensive discussion about how open platforms should be implemented, particularly about how the security measures should be put into practice. This discussion is based on an open platform which is successfully developed and deployed for a human resource company. A meticulous tradeoff is made between openness and security concerns for this open platform.
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Computer Engineering. 2012, 38(12): 268-271. https://doi.org/10.3969/j.issn.1000-3428.2012.12.079In view that the GPS/DR integrated navigation system in a complex environment has problems such as lower positioning accuracy, error accumulation of the DR and so on, a data fusion algorithm which has better performance is presented. Considering the latest observations of the traditional Particle Filter(PF), the Gaussian Mixture(GM) model based the Square Root of Second-order Divided Difference(SRDD2) is introduced to produce proposal distribution. The importance sampling based on Monte Carlo and the evolution re-sampling are employed respectively that do not reduce sample degradation of the traditional PF but enhance the diversity of the samples. Experimental results show that this design has better comprehensive navigation and positioning performance for integrated navigation system than PF algorithm, GMPF algorithm.
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Computer Engineering. 2012, 38(12): 272-275. https://doi.org/10.3969/j.issn.1000-3428.2012.12.080Aiming at the problems that vectorization compiler tool can not perform auto-vectorization or does blind auto-vectorization because of the insufficient of program analysis ability, this paper proposes a vectorization method based on the compiler directive. The compiler directive is used to guide vectorization compiler tool to perform some special actions and produce high efficiency vectorization code automaticly when it is inserted into the program. Test results show that the method can effectively improve the performance of the object code.
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Computer Engineering. 2012, 38(12): 276-278. https://doi.org/10.3969/j.issn.1000-3428.2012.12.081The problem is that Casper model can only adapt to the situation in which users are moving slowly. When users are in high-speed movement, Casper model can not construct good anonymous area and cause poor service quality. In order to solve this problem, this paper proposes a location privacy protection method based on V-grid model. It introduces V-grid model which takes in the parameter of users speed, updates users’ locations before constructing anonymous areas and meets kinds of users’ privacy need. Experimental results show that V-grid model has better applicability and achieves higher service quality than Casper model.
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Computer Engineering. 2012, 38(12): 279-282. https://doi.org/10.3969/j.issn.1000-3428.2012.12.082The signal control is an important factor for real-time traffic accuracy, which influences on traffic flow obviously. In this paper, urban road network travel time calculation model based on signal control is proposed, which gets no interference real time traffic data by separating the influence from signal control. The travel time is divided into two components: Link Valid Travel Time(LVTT) and Intersection Delay Time(IDT); and an optimized signal control delay model is proposed to calculate the IDT accurately. Besides, a link merger algorithm is also developed. Experimental results show that the travel time accuracy error of Origin Destination(OD) can be reduced by 5%~15%.
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Computer Engineering. 2012, 38(12): 283-286. https://doi.org/10.3969/j.issn.1000-3428.2012.12.083A distributed target assignment system based on multi-Agent is proposed in the presence of the characters of communication countermeasures target assignment. The problem of communication countermeasures target assignment is depicted and the model is built. The distributed cooperative auction mechanism and the distributed cooperative auction algorithm are designed. The distributed cooperative auction algorithm includes the tuba rule of auction sequence and the update role of target’s threatening degree. Simulation results show that this algorithm has the quicker convergence speed and the better real-time performance compared with the Genetic Algorithm(GA).
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Computer Engineering. 2012, 38(12): 287-290. https://doi.org/10.3969/j.issn.1000-3428.2012.12.084In the process of scheduling on multiprocessor real-time system, the value of the upper bound of interference influences on the performance of schedulability tests. The concept of slack is injected for the earliest deadline first scheduling algorithms, and a new test based on workload calculation is proposed. The possibility of task sets passing schedulability test is improved by decreasing the workload of all carried-in jobs in problem window. Experimental results show that the performance of the new test can be promoted from 5% to 10% than traditional one with the increase of processor’s number.
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Computer Engineering. 2012, 38(12): 291-292. https://doi.org/10.3969/j.issn.1000-3428.2012.12.085Most traditional approaches for stereo sensors calibration often require accurate calibration objects and complex procedures, which limit their capability in out-door work. This paper proposes a quick and flexible method for stereo sensors self-calibration which works on the essential matrix. It gets two cameras’ inner parameters off-line. And equation of the essential matrix calculates through matching the corresponding points in two corresponding pictures linearly. The outer parameters can also be got by calculation. Experimental results show that calibration results can be compared with traditional ones, and calibration procedures are quick and convenient. This method is also suitable for out-door operation.
2024
Volume 50 No 3
Volume 50 No 3
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428