20 September 2012, Volume 38 Issue 18
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Computer Engineering. 2012, 38(18): 1-5. https://doi.org/10.3969/j.issn.1000-3428.2012.18.001
This paper proposes a behavior trajectory restoration algorithm for observation sequence state missing problem, which leeds to terminal trajectory restoration inaccurately. The algorithm utilizes base station layout’s spatial correlation and revises the partial probability of the solution process of the Hidden Markov Models(HMM) to restore the track sequence without considering the missing observation states. Performance analysis and simulation results show that the greater the degree of state propensity is, the higher the success rate of trajectory restoration is. When the degree of state propensity is 0.8, the success rate of trajectory restoration is about 90 percent.
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Computer Engineering. 2012, 38(18): 6-10. https://doi.org/10.3969/j.issn.1000-3428.2012.18.002
In the single Low Earth Orbit(LEO) satellite localization system, grid search algorithm requires large amount of computation in the precision of search and Taylor-series linearization algorithm exists localization convergence problem. In view of this, a new method is proposed which is combined of grid search and Taylor-series linearization algorithm. Using grid search method to achieve the rough location and taking the location result as the initial value of the Taylor-series linearization, the high-precision position of target can be got. The constrained Cramer-Rao Lower Bound(CRLB) for the source localization estimation is derived with the constraints of altitude. Simulation results are provided to analyze the effects of various factors on the location precision. The analysis results show that the localization from frequency measurement by the single LEO satellite can effectively achieve the target location on both sides below the satellite.
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Computer Engineering. 2012, 38(18): 11-14. https://doi.org/10.3969/j.issn.1000-3428.2012.18.003
For solving the problem of tracking space target that has unknown maneuver under glint noise, an Adaptive Robust Unscented Particle Filtering(ARUPF) algorithm is proposed in this paper. Adaptive Robust Unscented Kalman Filtering(ARUKF) algorithm is designed by embedding adaptive robust filtering technique into Unscented Kalman filtering(UKF). ARUPF is developed by using ARUKF to generate the importance density function in Particle Filtering(PF). Combined with transient tracking model, ARUPF is applied for space maneuvering target autonomous tracking. Experimental result shows that the proposed algorithm improves the tracking accuracy and robustness, contrasting to the existing filtering algorithms.
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Computer Engineering. 2012, 38(18): 15-18. https://doi.org/10.3969/j.issn.1000-3428.2012.18.004
In the research of space handwriting recognition technology based on 3D accelerometer, a recognition method based on time-frequency fusion feature is proposed. From accelerometer data, it extracts the Short-time Energy(STE) feature. The hybrid feature which combines Wavelet Packet Decomposition with Fast Fourier Transform(WPD+FFT) are extracted, then the above two categories features are fused together and the Principal Component Analysis(PCA) is employed to reduce the dimension of the fusion feature. Supported Vector Machine(SVM) is used in recognition. Experimental results show that the proposed method can improve the performance of 3D space handwriting recognition system.
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Computer Engineering. 2012, 38(18): 19-21. https://doi.org/10.3969/j.issn.1000-3428.2012.18.005
This paper proposes a modified Perceptual Evaluation of Speech Quality(PESQ) algorithm to improve the performance of objective speech quality evaluation. Syllable stability detection and Unvoiced/Voiced/Silence(UVS) classification are used in the proposed method. Parameters of stability of frames and syllables distortions are used to describe the effect to hearing perception, and these parameters are different to variant speech segments, especially to unvoiced, voiced and silence segments. Experimental results show that the proposed algorithm for PESQ is able to improve correlation results for narrowband speech and can help to improve other speech quality evaluation.
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Computer Engineering. 2013, 38(18): 22-25. https://doi.org/10.3969/j.issn.1000-3428.2012.18.006
This paper deeply investigates the homograph in Uyghur language and classifies them according to the different features of homograph, disambiguates the first type of homograph according to the mapping relation between the part of speech and pronunciation, disambiguates the second type of homograph according to vowel weakening when suffix attaches to a stem, and optimal pronunciation mapping method is used to disambiguate the third type of homograph by extracting the contextual features of homograph. Log-likelihood ratio is used to select keywords and keyword selection experiment of different window size is also conducted. Experimental result shows that the homograph disambiguation performance of can be got to 20.9% error rate through the research idea of this paper.
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Computer Engineering. 2012, 38(18): 26-29. https://doi.org/10.3969/j.issn.1000-3428.2012.18.007In order to improve the compression code utilization, this paper presents a compressed bitmap index technology in column-oriented database. It defines the inversion and merges operations to transform the input and output of all calculation to the bitmap vector. By using a vitality to describe the complexity of each bitmap vector and directly operating on the compressed bitmap vector, the technology optimizes the data extraction in query execution process of where and group by clauses. Experimental research on SSB dataset shows that the technology improves 29.7%~38.9% of the index performance on compressed bitmap.
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Computer Engineering. 2012, 38(18): 30-33. https://doi.org/10.3969/j.issn.1000-3428.2012.18.008Because of the complexity and uncertainty of parallel behaviors, currently it is difficult to get atom rules from concurrent programs. Aiming at the problem, this paper presents a new atom property extraction method in concurrent program. A technique to automatically extract atom property from programs forms graph structure by using a frequent subgraph mining algorithm. It targets at inferring atomicity of both low level read-write operations as well as high level functional operations on multiple variables with rich structure information. Experimental result shows that this method manages to find atom property with a relatively high accuracy.
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Computer Engineering. 2012, 38(18): 34-36. https://doi.org/10.3969/j.issn.1000-3428.2012.18.009In distributed data stream mining, communication loads and global classification accuracy are main problems. In order to solve the problem, this paper presents a distributed data stream mining algorithm based on Support Vector Data Description(SVDD). Local site quickly updates data stream information, gets meta-level data by Support Vector Machine(SVM), and transmits them to central site. Central site receives and combines meta-level data, and learns global classification model. Experimental result shows that the algorithm can reduce transmission between local site and central site, and keep better classification accuracy.
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Computer Engineering. 2012, 38(18): 37-41. https://doi.org/10.3969/j.issn.1000-3428.2012.18.010Based on the Non-functional Requirement Conflict Management Meta-model(NFRCMM), this paper gives formalization description for modeling elements, and makes the definition of requirement semantic conflict as the foundation of checking requirement conflict. According to the different types and degrees of requirement conflict, a resolution method for conflict elimination and conflict decrease is provided. As the example of calculation travel costs service nonfunctional requirements in tourism travel field, it verifies the effectiveness of the proposed method.
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Computer Engineering. 2012, 38(18): 42-44. https://doi.org/10.3969/j.issn.1000-3428.2012.18.011Because of indexical high complexity of establishment, superior difficulty of maintenance and high consumption of space, an improved suffix tree full-text index model is proposed for those drawbacks of the traditional one. It divides the relatively large suffix tree into several Three Dimensional Suffix Tree(3DST). It makes the establishment and maintenance of index more convenient and faster by simplifying the structure of the suffix tree. Meanwhile, the improved model reduces the space and increases time and space efficiency by making the common prefix of Adjacent Character Pair(ACP) root node of the suffix tree. Experimental result shows that the improved model has a higher space and time efficiency than the traditional one.
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Computer Engineering. 2012, 38(18): 45-49. https://doi.org/10.3969/j.issn.1000-3428.2012.18.012Main existing algorithms mining asynchronous periodic patterns in time-series databases are designed to find i-patterns by enumeration based on the mining of valid segments and periodic patterns of 1-pattern, and time complexity is high. An improved algorithm based on Sequitur algorithm to mine asynchronous periodic pattern is proposed. It generates candidates for patterns based on the Sequitur algorithm to mine the recurring segments and their time-lists of events after the symbolization of time series. Then an algorithm generating valid segments of i-patterns based on One Event One Pattern(OEOP) algorithm is devised to mine directly some complex patterns, and finally valid subsequences are discovered. Experimental result demonstrates that this method has good mining efficiency.
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Computer Engineering. 2012, 38(18): 50-52. https://doi.org/10.3969/j.issn.1000-3428.2012.18.013Aiming at the accuracy for the impact of noise on the matching problem, this paper proposes an improved approximate subgraph matching method. In the preprocessing stage, it uses k-nearest neighbor graph for the vertices data set to establish a label-weight vector index. In the query process, it uses a single label weighting distance and the matching of the vertex’s all neighbors for two levels matching filter to generate a candidate set of vertices; then spans tree matching and graph matching query graph in the process of determining the positioning of large networks. Experimental result on real data sets shows that the algorithm runs efficiently and it has higher accuracy.
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Computer Engineering. 2012, 38(18): 53-56. https://doi.org/10.3969/j.issn.1000-3428.2012.18.014By analyzing the features and requirements of business process for scientific computing, this paper proposes a business process meta-model and a Smart Process Modeling Language(SPML) for scientific computing, and gives formal description of field meta-model and conversion algorithm from SPML to business process execution language. It designs and implements a business process modeling system based on SPML. Analysis result shows that this system can help users analyze and abstract business process modeling. It also can create an executable project and deployment file, and complete automatic deployment of process.
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Computer Engineering. 2012, 38(18): 57-60. https://doi.org/10.3969/j.issn.1000-3428.2012.18.015As existing Android system does not support users to customize the permissions of applications in it, this paper extends the existing Android application permission management mechanism, and proposes a fine-grained Android application permission management model compared to the existing application permission management ability. It retains the existing Android security mechanism, and users can freely customize the permissions of applications that are installed in it through the friendly GUI. Experimental results show that the model can provide users a practical and fine-grained Android application permissions management function, and it has less loss of the system performance.
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Computer Engineering. 2012, 38(18): 61-64. https://doi.org/10.3969/j.issn.1000-3428.2012.18.016In view of military message structure and characteristics of its software, an intelligent brute Fuzzing test approach for construction of abnormality data is proposed. According to the principles and ideas of Fuzzing, military message software security vulnerability discovery system named MTSFuzzer is developed. Meanwhile, software architecture, modules and key techniques are analyzed. Test result shows that MTSFuzzer improves the efficiency of military message software vulnerability exploiting, and it has good expansibility.
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Computer Engineering. 2012, 38(18): 65-67. https://doi.org/10.3969/j.issn.1000-3428.2012.18.017In order to solve the problem that traditional Geographic Information System(GIS) can not run well offline, this paper uses native storage and proposes a scheme called quad tree file system, which is based on quad tree index, and it prevents the storage from the shortcoming using windows file system. The main function includes inserting, reading, querying and deleting, it encrypts the data using simple method, which improves the data security. Experimental results show that the scheme is better than Windows file system for storing native data.
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Computer Engineering. 2012, 38(18): 68-72. https://doi.org/10.3969/j.issn.1000-3428.2012.18.018Aiming at index system and evaluating method is not appropriate to assess the creditability of battlefield communication network’s simulation system, based on the characteristics of protocol model, network environment and the simulation performance, a hierarchical index system is built up. Being dead against the logical and numerical index, an integrated assessing algorithm is proposed to rate the whole index system. Experimental results prove the system is pertinent, maneuverable and effective which combines the expert experience and impersonal observation well.
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Computer Engineering. 2012, 38(18): 73-76. https://doi.org/10.3969/j.issn.1000-3428.2012.18.019Aiming at the problem of quickly establishing links between satellite and ground, a new method of fast links establishment is proposed, link establishment data frame format is designed, and the basic principles of pseudo-random length is given. In this paper, the mathematical model of link establishment probability and link establishment time is built, and the link establishment modes are repetitiously simulated. Simulation results demonstrate that under the precondition of guaranteeing link establishment time analogous to transmission time, with the SNR of ?20 dB, link establishment probability is close to 1.
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Computer Engineering. 2012, 38(18): 77-79. https://doi.org/10.3969/j.issn.1000-3428.2012.18.020Split Multipath Routing(SMR) protocol can not transmit split data efficiently and the condition of route discovery during route maintenance process is unreasonable in Ad Hoc network. To solve the problem, this paper proposes a new routing protocol P-SMR, the protocol uses delay as influence factor of the data allocation methods to improve transmission efficiency, and takes the number of broken paths and survival time of paths as conditions to find route. Simulation result show that compared with SMR and DSR protocol, average end-to-end delay and route cost decrease, and packet delivery fraction improves.
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Computer Engineering. 2012, 38(18): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2012.18.021Considering the shortages of precision on classic multidimensional scaling anchor-free localization algorithm, a new iterative majorization anchor-free localization algorithm based on multidimensional scaling is proposed. The algorithm assumes an objective function and an iterative majorization formula. When the objective function value is minimal, the relative coordinates of the nodes are obtained. Through theoretical analysis and simulations, the algorithm provides a lower localization error than classical MDS algorithm. The localization precision is improved by 2.95%, realizing the node localization effectively.
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Computer Engineering. 2012, 38(18): 83-86. https://doi.org/10.3969/j.issn.1000-3428.2012.18.022Two steps are put forward to improve the poor localization coverage of the Time of Flight(TOF) range-based algorithm in the sparse network. The initial values of estimated node locations which achieve the accuracy threshold with the iterative refinement method upgrade to anchor nodes. If there is adverse nodes in the network, estimate their classification and compute the position. Simulation results show that the improved algorithm has obviously better localization coverage at the cost of increasing appropriate communication and computation.
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Computer Engineering. 2012, 38(18): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2012.18.023In Vehicle Ad Hoc Networks(VANET) multi-hop communication with nodes of high speed, a problem of how to choose a next hop relay rapidly makes a significant sense. In this paper, a slot assignment for voice access named black-burst scheme based Time Division Multiple Address(TDMA) is proposed for channel access contention. The problem of relay selection can be solved as a method of voice access control with priority. Simulation results show that in scenarios of movement with different nodes distribution, a shorter access delay and a lower cost can be obtained in MAC protocols based on black-burst mechanism compared with the traditional TDMA random channel access method.
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Computer Engineering. 2012, 38(18): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2012.18.024In this paper, a new kind of hierarchical double-loop networks constructed by the Cartesian product Fm×Fm-1×…×F1×G(where G is Petersen graph and Fi is a special undirected double-loop network) and its optimal routing algorithm are proposed. Its properties are discussed. Through compared with the hierarchical double-loop networks constructed by Du Yan, et al(computer engineering and application, 2010, issue 34). Experimental result shows that this kind of networks is a new topology with good connection, shorter diameter and has a simple and optimal routing algorithm.
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Computer Engineering. 2012, 38(18): 93-96. https://doi.org/10.3969/j.issn.1000-3428.2012.18.025Aiming at the data compression problem in Wireless Sensor Network(WSN), this paper improves Douglas-Peucker(DP) compression algorithm, and puts forward an improved optimum curve data compression algorithm OCDCA. It reduces the number of nodes scanning data in compression process and decreases energy consumption. It uses best curve fitting method for monitoring data to do a straight line optimal fitting that makes the data can be compressed, and has higher compression accuracy. Simulation results show that the algorithm procedures easier, improves the accuracy of compression and compression efficiency, and reduces the energy consumption of the WSN.
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Computer Engineering. 2012, 38(18): 97-99. https://doi.org/10.3969/j.issn.1000-3428.2012.18.026In order to improve the security of secret data transmission, a steganographic algorithm of minimized distortion is proposed. In order to express the influence of the pixel modification on the whole statistic character, scalar values are assigned to every pixel based on smoothness and impact of different embedding mode on it. Embedding is actualized by choosing the proper embedding position and mode utilizing Syndrome-trellis Codes(STC). Experiments show that the proposed algorithm possesses a good undtetability.
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Computer Engineering. 2012, 38(18): 100-102. https://doi.org/10.3969/j.issn.1000-3428.2012.18.027One family of pseudorandom binary sequences are constructed from elliptic curves on finite field by using the multiplicative inverse. The properties of pseudorandom binary sequences are studied including the well-distribution measure and the correlation measure of order k. Through exponential sums along elliptic curves, the well-distribution measure and the correlation measure of order k are computed. The upper bound of well-distribution measure is p1/2lbplbN. The upper bound of correlation measure of order k is p1/2(lbp)klbN. Their magnitudes are O(N), which indicates that this family of sequences have good randomness.
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Computer Engineering. 2012, 38(18): 103-106. https://doi.org/10.3969/j.issn.1000-3428.2012.18.028Most secure Elliptic Curve Scalar Multiplication(ECSM) algorithms based on Point Verification(PV) and Coherency Check(CC) have low efficiency. Aiming at the problem, this paper proposes a new secure algorithm based on ternary representation and proves its correctness. The analysis about its efficiency in the affine coordinates and Jacobian coordinates is presented, whose result shows that the computational efficiency is improved while guaranteeing the security.
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Computer Engineering. 2012, 38(18): 107-110. https://doi.org/10.3969/j.issn.1000-3428.2012.18.029By using the same or similar behavior characteristics of malicious codes, this paper proposes a method based on model checking technology to recognize malicious behaviors in binary files. It extracts Control Flow Graph(CFG) from disassembled binary executable and builds program model with Kripke structure, then produces Linear Temporal Logic formula to describe malware specification. The model checker recognizes malicious behavior and denotes detected behavior in the CFG. Experimental result shows that compared with common antivirus software, the proposed method is more effectively in recognizing malicious behaviors.
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Computer Engineering. 2012, 38(18): 111-115. https://doi.org/10.3969/j.issn.1000-3428.2012.18.030Aiming at the problem that traditional SQL injection vulnerability detection results have low accurateness, this paper presents a detection method based on the comparison results of the Webpage’s Document Object Model(DOM) tree. By simplifying the Web comparison algorithm based on node sequences, it reduces the number of node compare times, and accelerates the detection. A corresponding SQL injection vulnerability detection prototype system is designed and implied. Experimental results indicate that the system has high detection efficiency and accurateness.
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Computer Engineering. 2012, 38(18): 116-119. https://doi.org/10.3969/j.issn.1000-3428.2012.18.031Electronic cash can seldom be transferred in the existing electronic cash schemes. Therefore, a transferable off-line cash scheme is proposed for electronic payment system, in which the cash is signed with restrictive blind signature and convertible partial signature is employed for cash transfer. In this cash system, the bank and TTP need not be involved online in each transaction, and therefore the system efficiency is improved. The security analysis show that the anonymity of the electronic cash can be revoked by the trusted party and the cheater can be found out when some fraud such as double spending occurs in the transaction.
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Computer Engineering. 2012, 38(18): 120-122. https://doi.org/10.3969/j.issn.1000-3428.2012.18.032In most secret sharing schemes with weighted participants, different amount of players’ secret subshares can cause unfairness problem in the secret reconstruction phase. This paper proposes a rational secret sharing scheme based on repeated games. On the basis of original subshares, it constructs new subshares for each player, making sure that each two amount of subshares differ by a value at most 1. Through repeated games, every player can get all of other players’ subshares and then reconstruct the secret. Analysis result shows that the scheme can make every rational player follow the secret reconstruction protocol all the time and be able to reconstruct the secret. And it has high security and expandability.
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Computer Engineering. 2012, 38(18): 123-125. https://doi.org/10.3969/j.issn.1000-3428.2012.18.033Compromised nodes in Wireless Sensor Network(WSN) cause black hole. Based on SEEM algorithm, a low-complexity secure data collection algorithm is proposed in this paper. It uses a feedback-acking mechanism, which makes full use of property of multipath routing to achieving security of data transmission. Simulation experiments show that, compared with DRP and SPDC, the algorithm has higher quality of data transmission with less complexity.
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Computer Engineering. 2012, 38(18): 126-129. https://doi.org/10.3969/j.issn.1000-3428.2012.18.034Aiming at the security problem of Radio Frequency Identification(RFID) authentication protocol, this paper designs a secure RFID authentication protocol based on stream cipher, inspired from the challenge-response-based RFID authentication protocol for distributed database environment. Theory analysis proves that the proposed protocol can prevent several attacks including spoofing attack, replay attack, tracking and desynchronization. And it improves the efficiency of searching on the back-up database which makes the protocol more applicable.
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Computer Engineering. 2012, 38(18): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2012.18.035This paper proposes a design and implementation scheme of Gabor filter for fingerprint image enhancement. It employs accurate local orientation and frequency to achieve better enhancement effect. To address the subsequent problem of bandwidth increase, a specific Input/ Output(I/O) buffer is designed, which can almost cut off 10/11 bandwidth. At SMIC 0.13 μm technology, the equivalent gate count is 240 000, while the frequency is 250 MHz. Due to the introduction of pipeline, the design scheme can achieve a throughput more than 2 Mpixels/s, when convolution kernel size is 11×11. Experimental result shows that the scheme can well satisfy the requirements of the real-time applications.
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Computer Engineering. 2012, 38(18): 133-136. https://doi.org/10.3969/j.issn.1000-3428.2012.18.036Since the decode operation is frequent, which makes the efficiency of algorithms not so outstanding, a novel Quantum-inspired Immune Clonal Algorithm Based on Real Encoding(RQICA) is proposed. This algorithm exploits real-coded method and introduces chaos variables that are produced by logistic mapping into quantum rotation gates to improve searching capability. Experimental results demonstrate that when solving continuous optimization problems, this novel algorithm has a strong ability of global optimization and improves optimization efficiency of common quantum-inspired immune clonal algorithm remarkably.
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Computer Engineering. 2012, 38(18): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2012.18.037This paper focuses on the explosion in states when many regular expressions are grouped together into a single Deterministic Finite Automaton(DFA). Based on the original grouping algorithm, an improved algorithm is proposed by introducing graph partitioning. The proposed algorithm can reduce 30% states number on average when group number is same to the original one, and sometimes gets fewer groups. Experimental results show that the proposed algorithm can reduce the complexity of matching algorithm effectively.
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Computer Engineering. 2012, 38(18): 140-143. https://doi.org/10.3969/j.issn.1000-3428.2012.18.038In order to accurately track target during a long term in complex environment, this paper presents an algorithm combining detecting and tracking based on online learning and construction constraint. Improved optical flow method is used to adaptively track specific target. The nonhierarchical structure online learning random ferns classifier is used as real time target detecting method. In order to adapt target shape variation, unsupervised learning method based on construction constraint is used to accurately determine the target position. Experimental results show that this algorithm can adapt to the basic target shape variations and track the target steadily when the targets change in size, rotate, shelter partly or disappear in a short term.
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Computer Engineering. 2012, 38(18): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2012.18.039For solving the problems of basic harmony search algorithm can not be well used for multi-objective optimization, a kind of neighborhood search operator is introduced to improve the traditional harmony search algorithm. In the harmony memory of the proposed algorithm, every variable is disturbed by neighborhood search operator. Out of the harmony memory, every variable will be searched by Pareto neighborhood search operator. So it can exchange information between the populations during the proceeding of evolutionary and enhance the global searching ability of harmony search algorithm. Numerical experiments compare with NSGA-II, SPEA2 and MOPSO on four benchmark problems. The results show the effectiveness of the proposed algorithm.
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Computer Engineering. 2012, 38(18): 147-150. https://doi.org/10.3969/j.issn.1000-3428.2012.18.040Processing delay stroke is a difficulty in online Uyghur handwriting recognition. Because sample data format is a timing sequence, it makes letter’s main stroke and delay strokes uncontinuous in sequence. It greatly increases the difficulty of processing delay stokes and recognizing handwriting word. To solve this uncontinuous problem, this paper proposes a delay stroke processing method which contains seeking and projection of delay strokes. Result shows this method is robust and recognition accuracy rate is up to 93.25%.
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Computer Engineering. 2012, 38(18): 151-154. https://doi.org/10.3969/j.issn.1000-3428.2012.18.041For complex background color face image with color bias, high light and shadow, existing model cannot get satisfactory segmentation results. In order to solve this problem, this paper presents a skin color segmentation algorithm based on CbCgCr ellipsoid likelihood smoothness. This paper segments the skin region using smoothness of CbCgCr ellipsoid skin likelihood. It preprocesses the facial input image for eliminating the color bias, high light and shadow, calculates the smoothness of skin color likelihood of facial input image after processing by building on CbCgCr ellipsoid skin color model, and then roughly segments the skin region by using the smoothness of skin color likelihood, removes the noise of skin color coarse segmentation image and gets the skin color fine segmented image and fine extracted image. Experimental results show that the algorithm has good results and robustness of skin color segmentation for color facial image with unequal illumination and complex background.
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Computer Engineering. 2012, 38(18): 155-157. https://doi.org/10.3969/j.issn.1000-3428.2012.18.042To improve the global exploration and local exploitation ability of Particle Swarm Optimization(PSO) algorithm, an improved PSO algorithm integrated with Tabu Search(TS) is proposed. In PSO algorithm, optimal particle is perturbed with a linear increasing probability. When the global PSO algorithm converges to a certain degree, TS algorithm is used for local search of global optimum. Simulation results show that the convergence precision of the improved algorithm is very high, and can overcome premature convergence effectively.
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Computer Engineering. 2012, 38(18): 158-161. https://doi.org/10.3969/j.issn.1000-3428.2012.18.043The spatial data is complex, changeful, and mass, so the work of spatial data analysis is onerous, a spatial clustering algorithm based on multi-agent technology and mathematic morphology is proposed to solve this problem. The structural element of the mathematic morphology is selected as Agent. Based on the values of Moore Neighborhood or VN Neighborhood in the environment of their spatial location, the Agents autonomously choose OCC operator to do gray dilation or erosion operation to implement spatial clustering. Experimental results show that this algorithm has significant accuracy, reliability, flexibility, and can rapidly cluster any shapes of clustering.
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Computer Engineering. 2012, 38(18): 162-165. https://doi.org/10.3969/j.issn.1000-3428.2012.18.044This paper addresses the theoretical model, structure and parameter learning algorithms, two kinds of inference problems of Markov Logic Network(MLN) and its applications in Information Extraction(IE), including named entity recognition, entity relation extraction and entity resolution. MLN model can combine one-order predicate logic and probability graph model, fuse modular knowledge into Markov network, and describe complicate characteristics.
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Computer Engineering. 2012, 38(18): 166-170. https://doi.org/10.3969/j.issn.1000-3428.2012.18.045Moving objects can be converted into background ones by Gaussian Mixture Model(GMM) when they might be staying still in the scene for an uncertain time. Therefore, a new method based on improved GMM is proposed. To obtain complete objects, a background learning parameter is introduced to update the model according to the detection result in previous frame. Moreover, the information of 8-adjacent connection area is utilized to suppress noises and improve its stability in the complex environment. Several experiments are implemented and the results demonstrate its effectiveness in detecting the moving objects which stay briefly in the complicated condition.
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Computer Engineering. 2012, 38(18): 171-173. https://doi.org/10.3969/j.issn.1000-3428.2012.18.046The traditional algorithm of BP neural network based on Map Reduce framework has been researched. But the convergence speed of traditional BP algorithm is quite slow. The training is easily into local minimum spot. The iterations of processing training data are quite frequency, a great waste of resources. The proposed design thus parallels the improved BP neural network based on Map Reduce. The adjustment of self-adaptive learning rate and momentum factors are implemented in this design. The proposed design also uses maximum classification probability factor and preprocess method to enhance the correctness. Experimental result shows that improved parallel algorithm costs 17 times shorter than the primary. The accuracy is also improved further.
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Computer Engineering. 2012, 38(18): 174-177. https://doi.org/10.3969/j.issn.1000-3428.2012.18.047Multi-skill demand field product service scheduling problem is the combination of the multi-Travelling Salesman Problem(TSP) and the multi-skill project scheduling problem, it need consider routing optimization as well as service skills matching. A model of multi-skill demand field product service with time windows is built, in which the two objective dimensions are traveling time and client’s waiting time. A multi-part chromosome technique based genetic algorithm with corresponding segment crossover technique is proposed as a solution. A set of benchmark data are used to prove the effectiveness of the modified algorithm. The results prove that the modified algorithm can better avoid premature convergence and obtain a more optimal solution and the search efficiency is improved.
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Computer Engineering. 2012, 38(18): 178-181. https://doi.org/10.3969/j.issn.1000-3428.2012.18.048In this paper, in order to solve the collision detection in the virtual roaming system of moving object, a collision detection method based on line of sight is proposed. It analyzes the basic principle of collision detection and collision detection based on line of sight in Virtual Reality(VR) roaming environment. This paper adopts the membership function of fuzzy control method to improve the efficiency of collision detection. Experimental results show that this method can improve the calculation efficiency, ensure the accuracy of detection, and can avoid the wall and obstacles.
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Computer Engineering. 2012, 38(18): 182-185. https://doi.org/10.3969/j.issn.1000-3428.2012.18.049A Heterogeneous Multiple Ant Colony algorithm based on Survival of Fittest rules(HMACSF) is presented. This algorithm introduces more than one type of ant colony. All types of ant colonies with different pheromone updating mechanism and searching traits have mutual compensation of advantages, as well as mutual competitive exclusion. According to the results of the exchanging, HMACSF retains the dominant colonies, weeds out the inferiors, and improves the solving efficiency and diversity of solutions, to easily converge the global optimal solution. A series of Traveling Salesman Problem(TSP) experiments show that this algorithm can generate solutions with better quality and faster speed.
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Computer Engineering. 2012, 38(18): 186-189. https://doi.org/10.3969/j.issn.1000-3428.2012.18.050Aiming at the large difference of local image context under different imaging condition, which leads to descriptors can not be matched correctly, this paper presents a descriptor based on stable region. It uses Maximally Stable Extremal Region(MSER) detector to extract the stable image region, then assigns the consistent orientation based on stable regions and computing the descriptor based on log-polar coordinate in the larger neighborhood that adapted to keypoint’s scale. It applies the descriptor in the CT image registration of Printed Circuit Board(PCB). Application results show that this descriptor is invariant to image rotation and can be used to perform reliable matching when the local image context changes, and has the distinctive performance to resolve ambiguities. The descriptor can work well in the CT image registration of PCB.
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Computer Engineering. 2012, 38(18): 190-193. https://doi.org/10.3969/j.issn.1000-3428.2012.18.051Laplacian edge detection algorithm is widely used in the removal of cosmic ray noise in the CCD astronomical images, but it has higher computation complexity of single CPU. To solve this problem, this paper proposes a parallel Laplacian edge detection algorithm with Graphic Processor Unit(GPU) based on Compute Unified Device Architecture(CUDA) by analyzing the parallelism of Laplacian edge detection. The main algorithm running on the main CPU is responsible for split the astronomical image into some subgraphs. Then it sets Block and Grid size according to the GPU hardware configuration, and transfers the subgraph to graphics card for parallel computing. Finally it retrieve the processed subgraph to main memory and joining together to get complete image output. Experimental results show that, with the image size increases, the speed advantage of the parallel algorithm is greater than the serial algorithm, and it obtains more than ten times speedup measured.
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Computer Engineering. 2012, 38(18): 194-197. https://doi.org/10.3969/j.issn.1000-3428.2012.18.052It is difficult to determine the threshold and weight coefficients in image segmentation. Aiming at this problem, this paper proposes a new image segmentation algorithm based on graph theory. It uses two-dimensional Gaussian distribution function as the edge weight coefficient for it is dynamic adaptive, as well as resorts the regional-regional and inter-regional similarity function to delimit the gap function, and finds a dynamics determine function for the area to be merged or segmented. Experimental results show that this algorithm is better than other similar ones in image segmentation, and it can save the running time.
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Computer Engineering. 2012, 38(18): 198-202. https://doi.org/10.3969/j.issn.1000-3428.2012.18.053In the case of moisture detection of grain storage outside the granary, a cross-hole radar tomography method is used to detect the abnormal objects in the granary. According to the basic theory of tomography, wavefront ray tracing methods are being researched. Travel-time equation method is used to correct refraction points after wave before ray tracing. It improves the precision of ray tracing. Velocity and attenuation tomography forward model are built, and Least Square QR-factorization(LSQR) image rebuild methods are adopted to solve the inversion equation. Simulation results show the better performance of the improved ray tracing proposed in this paper, and using cross-hole radar tomography method to detect the inside structure of barn is feasible.
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Computer Engineering. 2012, 38(18): 203-206. https://doi.org/10.3969/j.issn.1000-3428.2012.18.054The localization property of Local Binary Fitting(LBF) model may introduce many local minimums of the energy functional. In order to overcome this problem, an active contour model based on local and global fitting is proposed. By introducing a characteristic function which measures the intensity distribution in a local region of a certain point, the proposed model combines the global fitting energy in CV model and the local fitting energy in LBF model. The proposed model not only retains the advantages of LBF model in segmentation of intensity inhomogeneity images, but also introduces the advantages of global convergence of CV model. Experimental results demonstrate that the proposed model can segment images with intensity inhomogeneity, while it allows for flexible initialization of the contours, and it is less sensitive to noise.
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Computer Engineering. 2012, 38(18): 207-210. https://doi.org/10.3969/j.issn.1000-3428.2012.18.055Aiming at drawbacks of the poor de-noising capacity for high-density noised images, a novel filtering algorithm of high density salt and pepper noise is proposed in this paper. The algorithm is adopted to separate the pixels in the image into signal pixels and noise pixels. It calculates the median value of the non salt and pepper pixels in the window centered at the current salt and pepper pixel, while signal pixels hold their gray values and be output unprocessed. The steps above are repeated until there is no noise replaced. Experimental results show that the algorithm can suppress noise effectively and preserve the image details. Contrasted to the traditional median filtering algorithm and its improved algorithms, it has better filtering performance.
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Computer Engineering. 2012, 38(18): 211-214. https://doi.org/10.3969/j.issn.1000-3428.2012.18.056In order to improve the quality of image restoration for motion blur images with noise signal, a new motion blur length estimation algorithm based on the principle of the correlation is proposed in the paper. To find motion blur parameters, Radon transform method is used to estimate motion blur angle. It extracts gray value of pixels which is around blur center, calculates correlation for getting motion blur length, and uses Lucy-Richardson iterative algorithm to restore the degraded image. Experimental results show that the algorithm has better antinoise and faster iterative convergence speed.
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Computer Engineering. 2012, 38(18): 215-217. https://doi.org/10.3969/j.issn.1000-3428.2012.18.057Traditional edge detection methods of ochotona curzoniae image have the problems of being sensitive to noise, large detail information of edge being filtered, having discontinuous and fuzzy detected edge. Aiming at these problems, the edge detection method based on mathematical morphology is used in the edge detection of ochotona curzoniae image in this paper. Using the corrosion and expansion algorithm of mathematical morphology and constructing proper structural element fitting to geometric properties of the ochotona curzoniae image, the edge of ochotona curzoniae image is detected. Experimental results show that the better effect of edge detection can be obtained by using this method.
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Computer Engineering. 2012, 38(18): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2012.18.058Due to the fault that the pots distribute unevenly and may be focused in one place by the way of traditional rectangular boundary, this paper proposes a method of the convex polygon boundary to improve the defects in the traditional method, and presents the evaluation functions of the two methods at the same time. Experimental results show that the sample mean of the method is 24% lower than the traditional method, it is effective and viable to solve the problems of multi-point position.
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Computer Engineering. 2012, 38(18): 221-224. https://doi.org/10.3969/j.issn.1000-3428.2012.18.059Redundancy design is a kind of important means to improve the reliability of fault-tolerant design, however, the redundancy design exists two outstanding problems which are the synchronization problem and the packet-loss problem. This paper mainly takes a certain type of spaceflight high reliable rocket embedded computer development as the background and analyzes demands and characteristics of the rocket flight control task. By using interrupt and query combination mode, it puts forward a kind of information interaction scheme for “1+3” redundant structure based on DSP and dual-port RAM. Application results show that this kind of information interaction scheme solves the synchronization problem and the packet-loss problem and meets the real-time requirements, while achieves high reliability.
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Computer Engineering. 2012, 38(18): 225-227. https://doi.org/10.3969/j.issn.1000-3428.2012.18.060In order to solve the demand of the information about the effect of the disturbing gravitation on the long-range missile emission in the outside space of earth, this paper adopts gradient method to solve the disturbing gravity in the outside space. To solve the problem that it costs a lot of time and can not be calculated in time when it computes the disturbing gravity about long-range missile as well as its complex model. It adopts the parallel method of principal and subordinate mode. Experimental result shows that adopting parallel method to solve the disturbing gravity of trajectory missile can reach the demand of fast computing by computer and get a high precision.
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Computer Engineering. 2012, 38(18): 228-230. https://doi.org/10.3969/j.issn.1000-3428.2012.18.061According to the characteristics of land vehicle navigation, the single degree of freedom accelerometer can be used as a substitute for the odometer. The Dead Reckoning(DR) scheme is proposed based on a low-cost single accelerometer with a single gyroscope. The DR system’s error accumulates over time, although it has high precision in a short while. Therefore, a GPS/DR integrated navigation system is formed by utilizing the Extented Kalman Filter(EKF). It combines the advantages of both systems and improves the navigation capacity. Actual test result shows that the GPS/DR integrated navigation system can satisfy the basic requirement of land vehicle navigation. It improves the degree of precision in the city valley and is able to work even when GPS signals are masked.
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Computer Engineering. 2012, 38(18): 231-233. https://doi.org/10.3969/j.issn.1000-3428.2012.18.062In view of the low efficiency of software performance in multi-pattern matching algorithm, a new hardware-based solution based on Field Programmable Gate Array(FPGA) is proposed. By using Bloom Filter(BF) data window collapsing, the on-chip hardware resource consumption is reduced and efficiency is improved. To reduce the possibility of false positive, the multilevel-verification is applied. A pipeline parallel structure is used to improve the query efficiency, which makes the pattern matching work in the high performance with no false positive. The method is applied in a high-speed network intrusion detection system. Experimental result shows that the throughout of system can reach the line speed of 10 Gb/s.
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Computer Engineering. 2012, 38(18): 234-237. https://doi.org/10.3969/j.issn.1000-3428.2012.18.063To cancel the restriction on symbolic method in analog circuit testability computing, an new testability evaluation method is proposed. When the coefficient of the item with highest power in the denominator polynomial of the fault diagnosis equation is not equal to 1, the circuit testability is computed after equivalent transformation of the original diagnosis equation, so the method can do with any diagnosis equation, and voids the error introduction in the process of testability computing. Example circuit analysis and engineering application show that the method is more simple and accurate, and is applicable in analog circuit automatic test and fault diagnosis.
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Computer Engineering. 2012, 38(18): 238-240. https://doi.org/10.3969/j.issn.1000-3428.2012.18.064Aiming at the radio signal interference and collision problem suffered by nearby nodes when ranging concurrently in mine localization system, which result in localization precision deteriorated and nodes energy wasted, this paper proposes a novel on-demand ranging scheduling algorithm. By adopting the strategy of mobile nodes putting forward localization demand actively and anchors dynamic grouping autonomously, ranging collision in mine localization system is effectively avoided and the influence of localization dead area is mitigated. Simulation result shows that, compared with other schedule algorithm based on invariable group, the algorithm performs better in higher localization coverage, smaller localization delay and the localization error of mobile miners is reduced greatly.
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Computer Engineering. 2012, 38(18): 241-244. https://doi.org/10.3969/j.issn.1000-3428.2012.18.065For the parallel computer system with distributed memory, the communication overhead is an all-important optimizing factor to improve the performance of parallel simulation program. To reduce the absolute communication latency between nodes, represented by a typical Synthetic Aperture Radar(SAR) imaging program, namely R-D, this paper researches on avoiding communication latency techniques for SAR imaging parallel simulation. Four important components are researched, including reducing communication numbers, reducing communication granularity, selecting appropriate communication block, and adopting efficient communication function library. Experimental results show that the SAR imaging program optimized by avoiding communication latency can present high net bandwidth utilization, and achieve obvious performance improvement.
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Computer Engineering. 2012, 38(18): 245-247. https://doi.org/10.3969/j.issn.1000-3428.2012.18.066The test of Integrated Circuits(IC) always encounter a lot of problems, like processing the huge test data volume, spending a long time to test and construct the complex test structure. This paper proposes a hybrid test method to compress test data volume based on multiple scan chains. Using pseudo-random pattern generator generates test vector which includes more does not care bits. The rest of vectors are stored by Automatic Test Equipment(ATE) directly. Both theory and experiment show that the proposed method can achieve better compression performance compared with the scan disabling-based BIST-aided Scan Test(BAST) scheme.
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Computer Engineering. 2012, 38(18): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2012.18.067According to the situation that readers are distributed densely and tags move randomly, it is necessary for Radio Frequency Identification(RFID) system to identify and track tags. This paper proposes an improved Virtual Route Tracking(VRT) algorithm to tracking tags, and comes up with the method to process the abnormal situation that a tag is inducted by more than a reader at the same time or leaked by readers. The results show that the algorithm reduces error sources of introduction and beyond the restrictions of reader number, so that the tag is always tracked even in abnormlities, and ensures that the RFID network has preferable robustness.
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Computer Engineering. 2012, 38(18): 251-254. https://doi.org/10.3969/j.issn.1000-3428.2012.18.068Based on the character of humming melody extraction and qualitative mapping, combining with the music theory, a qualitative mapping model for extracting humming melody and its algorithm are given in this paper. The key points of the algorithm are the method to choose the criterion of the note segmentation dynamically and the dynamic measure to determine the pitch of a note. Experimental results show that not only a better result of choosing flexibly and reasonably the criterion of the note segmentation can be determined, but also the note pitch can be extracted accurately. The contour of humming melody can be achieved too.
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Computer Engineering. 2012, 38(18): 255-257. https://doi.org/10.3969/j.issn.1000-3428.2012.18.069The log generation system in this paper overcomes the traditional log generation system which cannot modify the generation of modules and levels log, the configuration file can be modified and the dynamic command can be used to get selective generation of different modules and levels log in this design. This design uses the scanning of configuration file, according to the identification of different modules and levels in configuration file to update the list of log generation, the dynamic command inputs with the Inter-process Communication(IPC) in process to update the list of log generation, then uses the API interface to generate the log according to the demand.
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Computer Engineering. 2012, 38(18): 258-261. https://doi.org/10.3969/j.issn.1000-3428.2012.18.070Scientific, objective, quantitative evaluation criterion are lack in product appearance design patent infringement judgment. In order to solve this problem, an improved metrics algorithm for product shape similarity based on complex spherere mapping is presented in this paper. Using STL model to characterize the product 3D model geometry features, a character description which containes the information of facets’ normal, area and space position, obtains by mapping the model facets to the smallest circumscribed sphere. The similarity of models can be calculated by accumulating the similarity of model’s each spherical unit. Experimental results show the stability and reliability of the algorithm are good.
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Computer Engineering. 2012, 38(18): 262-264. https://doi.org/10.3969/j.issn.1000-3428.2012.18.071In the computation of Graphics Processing Unit(GPU) platform, GPU equipment storage and memory capacity is different. Processed data usually cannot finish operation from memory copy to the video memory in one-time. In order to solve this problem, this paper proposes a Cholesky decomposition overlapped algorithm. By dividing the device storage into two buffers, current data and next data for calculation are stored in turn, data swap between device storage and memory takes place in the process of computation. Experimental results show that the algorithm can increase the system efficiency.
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Computer Engineering. 2012, 38(18): 265-267. https://doi.org/10.3969/j.issn.1000-3428.2012.18.072For increasing the throughput of the pseudo-random number generated by conventional linear feedback shift register, overcoming the drawback that 0 and 1 generated in one cycle does not match, a new architecture using leap-forward feedback shift register and De Bruijn counter is proposed. Theoretical analysis and simulation shows that the new algorithm has both the characteristics of high throughput and 01 balancing, so the new architecture is more complete in theory and suitable for high data rate environment.
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Computer Engineering. 2012, 38(18): 268-272. https://doi.org/10.3969/j.issn.1000-3428.2012.18.073Considering the conflicts among synchronization result, steam fluency and resource utilization traditional in stream transmission of embedded Video on Demand(VOD), an optimization scheme of code stream transmission synchronization is proposed. This scheme uses audio and video segmentation synchronization algorithm for sending data, uses the combination of audio adaptive jitter buffer algorithm and video de-jitter algorithm to reduce the jitter and packet loss rate, and does second A/V synchronization before decoding. It uses Buffer Based-additive Increase Multiplicative Decrease(BB-AIMD) algorithm to implement congestion control. Experimental results show this scheme ensures in-stream synchronization delay within 100 ms and out-stream synchronization delay around 125 ms, and significantly improves the stream fluency and resource utilization.
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Computer Engineering. 2012, 38(18): 273-276. https://doi.org/10.3969/j.issn.1000-3428.2012.18.074Since the simple physical model of current 3D game engine cannot truly reflect the vehicle baking state of motion, a virtual display simulation system of vehicle braking stability is proposed. The vehicle dynamic model including four-wheel vehicle model and wheel tire model is established. The upper simulation software is used to compute the dynamic model and to render the virtual scenes. The display method of tire state and the virtual meters are given, and then the virtual display system is designed and developed by 3D game engine. Experimental results show that this system can observe simultaneously the running state of vehicle and wheels, and reproduce behaviors of the wheel lock, vehicle yaw and sideslip. The dynamic model can satisfy the real-time and continuous requirement of screen rendering for virtual display.
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Computer Engineering. 2012, 38(18): 277-281. https://doi.org/10.3969/j.issn.1000-3428.2012.18.075In the cases of the restrictions of screen sizes on mobile terminals and the inflexible display of Web pages, it is hard and time-consuming for users to locate information. This paper proposes a personalized page-displaying system from the user’s perspective based-on mobile terminals. The system consists of some modules, such as establishment module of users’ interest library, page-segmenting module and learning module for calculating the importance of semantic blocks. The system can display title lists of Web pages on mobile terminals according to user’s personal interests and hobbies. Experimental results show that the system can locate information quickly and save searching time according to users’ different interests.
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Computer Engineering. 2012, 38(18): 282-285. https://doi.org/10.3969/j.issn.1000-3428.2012.18.076Cisco IOS processes can not be dynamically analyzed, and it is difficult to intercept system abnormalities of communication process. A method based on virtualaization is proposed to analyze Cisco IOS communication process. Hardware abstraction layer virtual machine is constructed, and a dynamic analysis platform based on virtualization is designed for IOS. This paper introduces methods for extracting key instruction stream and communication features. The multiple instruction set architecture and multiple versions of Cisco IOS is proved. Experimental results show that this method can effectively intercept the designated communication process.
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Computer Engineering. 2012, 38(18): 286-290. https://doi.org/10.3969/j.issn.1000-3428.2012.18.077Aiming at the difficulties of large water areas detailed simulation and the limitations of rendering efficiency, this paper presents a paralleled dynamic multi-resolution physical simulation model of water surface. In order to model water surface, it adopts a Level of Detail(LOD) progressive grid partition method which is relative to viewpoints, and utilizes Compute Unified Device Architecture(CUDA) and GPU technology to accelerate the solution of N-S equation. Experimental results show that the performance of the model can increase with the increases of the grid resolution, and reach more than 30 frame per second under the resolution of 1 024×1 024.
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Computer Engineering. 2012, 38(18): 291-292. https://doi.org/10.3969/j.issn.1000-3428.2012.18.078In order to improve the intelligence of detection, this paper deals with some common tire texture defects as research object, and adopts two template-based methods to detect defects in tires. The first method uses gray level co-occurrence matrix and histogram to extract texture features from tire, the second method uses one-dimensional Gabor to extract texture feature of tire. Defects detection is realized by comparing the similarities between texture features extracted respectively from the template and test images. Experimental results show that the second method is better than first one in the detection accuracy and more adaptive for multi-type defect checking.
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