20 October 2012, Volume 38 Issue 20
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Computer Engineering. 2012, 38(20): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2012.20.001
Aiming at the problem that the Cognitive User(CU) communication quality can not be ensured in the detect-avoid transmission mechanism of traditional Cognitive Radio(CR) system, a subspace decomposition based transmission mechanism is proposed, in which the advantage of Multiple Input Multiple Output(MIMO) about spatial processing is utilized. The noise space is calculated by using subspace decomposition of covariance matrix during the channel detection. The transmit signal is projected into the noise space combining precoding and the system performance is optimized by power waterfilling during the data transmitting. Simulation result shows that the proposed algorithm can realize the spatial multiplexing between the CU and Primary User(PU), in which the frequency spectrum utilization is enhanced effectively.
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Computer Engineering. 2012, 38(20): 5-8. https://doi.org/10.3969/j.issn.1000-3428.2012.20.002
This paper discusses the Structured Exception Handling(SEH) and related protection mechanism, from the perspective of attackers, summarizes the technology of SEH vulnerability exploitation. It uses heap addresses or addresses outside of protection modules to overwrite the pointer of SEH handles to bypass SafeSEH, and fakes SEH chain to bypass SEHOP. It analyzes some major methods of making program execution flow locate the Shellcode. Example verifies the effectiveness of the SHE vulnerability exploitation technology.
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Computer Engineering. 2012, 38(20): 9-12. https://doi.org/10.3969/j.issn.1000-3428.2012.20.003
Aiming at promoting the reusability and integratability of automotive software, this paper refers to the automotive open system architecture standard AUTOSAR Operating System(OS) specification which is a standard for automotive industry, discusses the design approach of function modules such as schedule table, OS-application and timing protection on the basis of OSEK/VDX OS. It implements it on MC9S08DZ60, which is a freescale 8-bit microprocessor chip. It tests storage demand and real-time performance of the system, the result of which shows the system meets the requirements of embedded real-time OS.
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Computer Engineering. 2012, 38(20): 13-16. https://doi.org/10.3969/j.issn.1000-3428.2012.20.004
Aiming at the defects of image encryption algorithms which only use the chaotic system’s significant properties, such as sensitivity to initial condition, to scrambling and diffusion, a new image encryption method that has to do with the plaintext image is proposed. Partial plaintext information is extracted, which is used to control the generation of keys that are prepared for encrypting the plaintext, then in the process of encryption the characteristic of the binary is carried on block encryption, and a diffusion encryption for above image is further treated. Theoretical analysis and simulation demonstrate that the algorithm has a large key space, and its encryption image is very sensitive to keys, so it has a good ability of anti-plaintext attacks and anti-statistics attacks, and is more safer than only scrambling and diffusing for image, moreover the experimental result is ideal, thus it can be widely used in information security field.
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Computer Engineering. 2012, 38(20): 17-20. https://doi.org/10.3969/j.issn.1000-3428.2012.20.005
A study of Markov characteristics for simplifying the model of high frequency channel is presented aiming at the problem of the randomly time-varying tap which is difficult to estimate. By partitioning the continuous-value channel gain into a finite number of states are modeled as a first-order Finite-state Markov(FSM) chain. The parameters of the FSM model such as stationary probability and transition probability are calculated with the given fading characteristic parameters. It analyzes the average error probability and the characteristics of state duration for the FSM model. The validity and accuracy of the model are confirmed by the simulation.
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Computer Engineering. 2012, 38(20): 21-25. https://doi.org/10.3969/j.issn.1000-3428.2012.20.006
The previous search on text error-detecting focused on words-level, and the syntax and semantic errors reasoning are not paid enough attention. Words, syntax and semantic knowledge bases are enlarged and constructed by taking advantage of statistic model and massive People’s Daily corpus to resolve the relevant level error reasoning, and the relevant multi-level reasoning model is put forward. The comprehensive three-level text proofreading algorithm is implemented. The constructed system can check various text errors. Experimental results show that the system has a better performance, and the recall rate is 85.62%.
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Computer Engineering. 2012, 38(20): 26-29. https://doi.org/10.3969/j.issn.1000-3428.2012.20.007In the processes of information synthesis with lots of database tables, the task with Change Data Capture(CDC) settings not only is fussy, but also it can affect the efficiency. For such a problem, from the software behaviors point of view, this paper designs a real-time information synthesis method. The software is under monitor by constructing behavior-data mapping, through which the CDC load of database can apportion to terminal computers. Actual test result indicates that the method is no concern about the type of database, and it has good feasibility and applicability.
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Computer Engineering. 2012, 38(20): 30-33. https://doi.org/10.3969/j.issn.1000-3428.2012.20.008In using workflow system, as business systems have large span and scale, and there are large numbers of interactive work within it, all of which increase the difficulty of simulation and testing. Under these circumstances, this paper puts forward a way that using Selenium to simulate and test the business systems in workflow. It can automatically simulate different participants’ complex interactive work and complete the implementation of the business processes in B/S structural business system. Application result shows that this method can automatically start and run multiple process instances at the same time, and test the performance of the system in the case of distributing large quantities of process instances.
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Computer Engineering. 2012, 38(20): 34-37. https://doi.org/10.3969/j.issn.1000-3428.2012.20.009This paper proposes a Web services selection algorithm with local and global Quality of Service(QoS) constraints. It transforms a Web services selection problem based on QoS into a multi-objective combinatorial optimization problem with QoS constraints. Some candidate services are filtered through the local QoS constraints. The Archived Multi-objective Simulated Annealing(AMOSA) algorithm is employed to produce a set of Pareto optimal solutions by means of optimizing multiple QoS objective functions simultaneously. These obtained Pareto optimal solutions are filtered through global QoS constraints. Experimental results show the effectiveness of the algorithm.
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Computer Engineering. 2012, 38(20): 38-10. https://doi.org/10.3969/j.issn.1000-3428.2012.20.010The widely use of the k-anonymity privacy protection model in the privacy protection field yields has a large number of k-anonymity data. For researching on the data dependency in k-anonymity data, this paper defines an Extended Functional Dependencies(EFDs), which extends the value of the right properties get from the certain set, instead of the equality in classic function dependencies. Application result shows that EFDs not only covers classic functional dependency, horizontal function dependencies, and metric functional dependencies, but also can describe the constraints of the k-anonymity data from perspective of data integrity and instruct the selection of quasi-identifier in k-anonymity privacy protection model.
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Computer Engineering. 2012, 38(20): 41-44. https://doi.org/10.3969/j.issn.1000-3428.2012.20.011Aiming at the problem of low quality of microblog data causing by colloquialism and non-normative of microblog language, this paper conducts cleansing microblog data using the centroid algorithm, degree-epicenter value and eigenvector-epicenter value algorithms in order to acquire high quality data, analyses the performance of the three cleansing algorithms after comparing the three attribute metric values such as normativity, relevance, helpfulness before and after cleansing process. Experimental result shows that the metric values of the whole quality of posts ascend obviously after processing by three cleansing algorithms, centroid algorithm shows better performance for attribute helpfulness, the degree-epicenter value and eigenvector-epicenter value algorithms help to acquire posts with strong similarity.
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Computer Engineering. 2012, 38(20): 45-48. https://doi.org/10.3969/j.issn.1000-3428.2012.20.012This paper presents a Web object extraction method based on Hierarchical Correlative-chain Conditional Random Fields(HCC-CRFs) model. This method performs data record detection and attributes labeling simultaneously to avoid error propagation. It can get the most out of the content hierarchy of Web page by adding more conditional dependencies between data record. Experimental results show this method has good extraction effect.
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Computer Engineering. 2012, 38(20): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2012.20.013Outsourced eXtensive Markup Language(XML) database query validation goal is to ensure that the data and structure of XML set credible. This paper designs a tree-based RMH authentication data structure, improves verification algorithm, guarantees the structure of XML data and the authenticity, integrity, current, and does not have privacy protection. Theoretical analysis and experimental results demonstrate that the scheme has smaller storage overhead, faster verification speed, higher security and so on, and it is superior to existing scheme.
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Computer Engineering. 2012, 38(20): 52-55. https://doi.org/10.3969/j.issn.1000-3428.2012.20.014The Ahead of Time(AOT) compilation is implemented on Harmony, which is an open source Java platform, to improve the ability of response and acquire high efficiency of Java codes in the real time environment. The AOT compiler stores executable codes in the form of files into disks or servers. It loads the file into the virtual machine, relocates codes, registers exception information and builds constant areas for all methods to make codes run correctly when it works. Operation results show AOT technology can improve the Java program response ability, and it has the high compiling efficiency compared with interpreter compiler and JIT compiler.
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Computer Engineering. 2012, 38(20): 56-59. https://doi.org/10.3969/j.issn.1000-3428.2012.20.015Aiming at LTE technology uplink interference problem, based on comprehensive analysis of existing various kinds of interference suppression technology, this paper presents a new uplink interference coordination scheme, which includes two steps, frequency band distribution and energy distribution. Less interference frequency band is assigned band to the users who are far from the base station, and centralized energy distribution algorithm is used to allocate appropriate power. After the computer simulation comparison with the existing scheme in throughput, efficiency, time delay, better experimental result is achieved.
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Computer Engineering. 2012, 38(20): 60-63. https://doi.org/10.3969/j.issn.1000-3428.2012.20.016EEPB is a chain-based protocol which has certain deficiencies including the uncertainty of threshold adopted when building chain, the inevitability of long link when valuing threshold inappropriately and the non-optimal election of leader node. Aiming at these problems, an Energy-efficient algorithm based on Triangle Module fusion Operator(EETMO) is proposed. EETMO adopts new method to build chain, and establishes membership functions of nodes residual energy and distance between a node and base station respectively, uses the fusion method of triangle module operator to determine the leader node selection. Experimental results show that EETMO has a better performance than EEPB on balancing energy consumption and prolonging lifetime of Wireless Sensor Network(WSN).
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Computer Engineering. 2012, 38(20): 64-67. https://doi.org/10.3969/j.issn.1000-3428.2012.20.017Based on the problem of the shortest path between two nodes in the exchanged hypercube network, the method of the graph theory is employed to study the topological property of the exchanged hypercube network by introducing the concept of similare subnet, the sufficient and necessary conditions which guarantee some link of one node to become a candidate link of the shortest path, are presented. At the same time, a shortest path routing algorithm with time complexity on the exchanged hypercube network is obtained, the theoretical analysis and the simulation result show that above algorithm can output the shortest path between any two nodes in the exchanged hypercube network.
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Computer Engineering. 2012, 38(20): 68-71. https://doi.org/10.3969/j.issn.1000-3428.2012.20.018Data collection in Wireless Sensor Network(WSN) research is the basic problem. This paper presents a data collection solution based on compressive sensing technique and mobile data collector. The regional scope of the incident is calculated by the analysis of spatial correlation of data, and a clustering algorithm is proposed based on residual energy of the nodes to carve up the region events. On this basis, each node senses the original data, based on the theory of compressed sensing. The data is sparse representation and observations by adopting Gaussian Random Matrix(GRM), and its observations are sent and stored in its cluster head, when a mobile collector enters the cluster head communication range, achieving the data collection. Theoretical analysis and simulation experimental results show that this scheme is energy efficient, and can effectively extend the network lifetime.
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Computer Engineering. 2012, 38(20): 72-75. https://doi.org/10.3969/j.issn.1000-3428.2012.20.019For simulation of the atmosphere channel in the Non-Line-of-Sight(NLOS) ultraviolet communications, this paper proposes the application of Maximum Likelihood Sequence Estimation(MLSE) in wireless ultraviolet NLOS communication. The probability density function of the received signals is derived in ultraviolet communication so that the output bit error rate of equalizer can be studied. The theoretical analysis and simulation results show that the performance of equalizer is nearly not affected by the attenuation coefficient and channel bandwidth for the short range communication, but is sensitive to variation of both for the long range communication with the same Signal-to-Noise Ratio(SNR). Meanwhile, the performance of equalizer is sensitive to variation of channel length, and not sensitive to modulation schemes.
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Computer Engineering. 2012, 38(20): 76-80. https://doi.org/10.3969/j.issn.1000-3428.2012.20.020Aiming at the security problem on routing in Ad hoc network, this paper presents a secure routing protocol based on trust evaluation in Ad hoc network. It uses the modified trust evaluation model, every node maintains a table of trust value. In the process of routing, it judges credibility of the previous hop and next hop in RREQ and RREP according to that table, and chooses the route considering both the value of route trust and hop count. The scheme makes trust evaluation and routing protocol have more connection with each other. Through NS2 simulation experiment, result shows that the protocol can avoid selfish node well, and it not only enhances the security, but also increases the routing efficiency.
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Computer Engineering. 2012, 38(20): 81-84. https://doi.org/10.3969/j.issn.1000-3428.2012.20.021Analysis indicates that Liaw et al’s remote user authentication scheme is vulnerable to replay attack, man-in-the-middle attack, and there are obvious security vulnerabilities in the password changing phase and registration phase. A remote user authentication scheme based on Diffie-Hellman(D-H) key exchange protocol is proposed. Theoretical analysis shows that the scheme can resist impersonation attack, replay attack, man-in-the-middle attack, and it can implement mutual authentication and session key generation securely.
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Computer Engineering. 2012, 38(20): 85-88. https://doi.org/10.3969/j.issn.1000-3428.2012.20.022In order to solve the problem that efficiency of current grouping proof schemes is low, this paper constructs a disordered and anonymous grouping proof Radio Frequency Identification(RFID) protocol based on elliptic curve discrete logarithm problem. This grouping proof protocol is disorderly created using the method of multiple signatures. The new scheme is proved to be secure and untracked, and compared with existed schemes, it uses only one scalar multiplication.
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Computer Engineering. 2012, 38(20): 89-92. https://doi.org/10.3969/j.issn.1000-3428.2012.20.023In view of the trusted computing can make up for the traditional security protection technology in architecture design and protection on the strength of security risks exist, this paper puts forward a kind of structural security model. From trust chain, it introduces the embedded trusted security module and one smart card module into trusted computing platform. The realization methods of the key technologies of J3210, JetOS, BIOS enhancement, OS security enhancement and user identity authentication based on smart card are given.
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Computer Engineering. 2012, 38(20): 93-96. https://doi.org/10.3969/j.issn.1000-3428.2012.20.024This paper has brought forward a way of image encryption algorithm based on multiple chaotic maps for improving the safety of image information. This algorithm regards the chaotic sequence and the pixel coordinate of the color image as two points in space, using the formula of the distance of two points in space to generate the sequences to encrypt the image. Simulation results demonstrate that the algorithm is easy to carry out, has a strong sensitive effect on the key, its key space is enough large, and it has very uniform pixel-value distribution.
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Computer Engineering. 2012, 38(20): 97-100. https://doi.org/10.3969/j.issn.1000-3428.2012.20.025In traditional Hardware-based Private Information Retrieval(HW-PIR) scheme, the plaintext records in database are easy to be revealed. In order to solve the problem, this paper proposes a new HW-PIR scheme based on encrypted database. A permutation after the database records is converted into (0,1) bit stream, which is to inquire the ciphertext database by using the Proxy Re-cryptography(PRC) algorithm, so that the scheme not only can ensure the user’s privacy information not be leaked to the database server, but also can prevent inquires information of users and database privacy being revealed to secure coprocessor and malicious attacks, which is much more secure. Efficiency analysis result shows that the complexity in online inquires stage is O(1), and the computational cost of secure coprocessor in preprocess stage is decreased obviously.
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Computer Engineering. 2012, 38(20): 101-104. https://doi.org/10.3969/j.issn.1000-3428.2012.20.026The robustness of common watermarking is poor when against some geometric attacks such as rotation, scaling, etc. According to this problem, a quantization watermarking method based on scale invariant feature by using ridgelet transform is proposed in this paper. In order to improve the robustness of watermark, the invariant feature local region is constructed by using the scale invariant feature transform, then the direction of the largest energy of ridgelet transform coefficients is selected by taking the ridgelet transform for local region. Finally, the watermark data is embedded into the largest energy coefficients by adopting the quantization index modulation method. Experimental results show that the method has good detection performance and good robustness when against common image processing attacks.
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Computer Engineering. 2012, 38(20): 105-108. https://doi.org/10.3969/j.issn.1000-3428.2012.20.027In order to protect the confidentiality and integrity of the high security level information in XML documents, by improving security labels of objects, *-property and three conversion rules of security states, this paper proposes Integrity-enhanced BLP(IEBLP) model. Analysis result shows that it can satisfy the requirements of confidentiality and integrity of the information simultaneously, and realizes fine-grained Mandatory Access Control(MAC) in XML documents.
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Computer Engineering. 2012, 38(20): 109-112. https://doi.org/10.3969/j.issn.1000-3428.2012.20.028In order to achieve semantic collocation from word collocation, this paper proposes a new model of extracting semantic collocation and a new representation method of semantic collocation. By introducing Special Degree(SD) as a tool and utilizing knowledge of the HowNet, 420 000 records of words collocation are converted to semantic collocation in a quantitative way. Experimental results show that the accuracy of semantic collocation reaches 92.1%, and the semantic collocation expands the scale of the words collocation effectively.
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Computer Engineering. 2012, 38(20): 113-115. https://doi.org/10.3969/j.issn.1000-3428.2012.20.029In order to enhance the execution efficient of thread scheduling and parallel performance in Chip Multi-processor(CMP), a kind of scheduling method of heuristic Particle Swarm Optimization(PSO) algorithm is proposed. This algorithm is based on the module of designed thread scheduling module and uses Direct Acyclic Graph(DAG) chart to express the dependence between threads. Meanwhile, it uses the new method for thread scheduling. Experimental result shows that the execution efficient of this method is prior to the genetic algorithm and can better reduce the task execution time and take full advantages of benefit of the multi-core structure.
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Computer Engineering. 2012, 38(20): 116-119. https://doi.org/10.3969/j.issn.1000-3428.2012.20.030To improve the watermelon seed automated screening system performance, this paper presents a method of watermelon seed combination parallel binocular stereo vision and bone line to use in measurement and process the warping degree of watermelon seed. This method uses binocular stereo vision technique for the reconstruction of three-dimensional object’s surface information. The three-dimensional information is projected in space rectangular coordinates, it can obtain the seed profile in the front view and side view. The combination of Curvature Scale Space(CSS) and bone line is used in feature extraction of the side view profile of the watermelon seed. Experimental results show that the method has high recognition accuracy for warped seed.
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Computer Engineering. 2012, 38(20): 124-127. https://doi.org/10.3969/j.issn.1000-3428.2012.20.032Marginal Fisher Analysis(MFA) algorithm is inadequate when it keeps the intrinsic geometric structure of images, and it only utilizes labeled data and wastes rich unlabeled data. This paper proposes a novel tensor subspace learning algorithm: semi-upervised discriminant analysis algorithm based on tensor. The method adopts the two-dimensional tensor to show the image samples, so it can perfectly detect the intrinsic geometric structure of the data manifold. Moreover, it sufficiently utilizes the labeled data which contains discriminant information and rich unlabeled data, which can maximize the discriminant between classes of data in low dimension subspace and assure the distant points in the high dimension space is distant in the low-dimensional space. Experimental results on PIE and FERET face databases show that this algorithm can achieve higher recognition rate.
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Computer Engineering. 2012, 38(20): 128-131. https://doi.org/10.3969/j.issn.1000-3428.2012.20.033A novel Interactive Max-Min Ant System(IMMAS) is proposed to overcome the weakness that conventional Ant Colony Optimization (ACO) algorithm can not effectively solve the problem of qualitative system whose optimization indices are unable or difficult to be quantificated. In order to enhance searching performance of the algorithm and reduce user fatigue, pheromone on the paths is limited to a maximum-minimum intervals and updated by the globally best solution, and IMMAS user only need select a mostly interesting individual of current generation, and need not evaluate quantization of every solution. In the test of the application to the car styling design, the proposed algorithm achieves good search ability and high convergence speed.
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Computer Engineering. 2012, 38(20): 132-135. https://doi.org/10.3969/j.issn.1000-3428.2012.20.034In order to solve the problem of multi-object detection and tracking in real-time with the moving camera, this paper uses Global K-means based on affine transform model along with template matching. It adopts the affine transform model to get the global motion and compensates it between images. The Global K-means method is used to iteratively cluster the foreground points and decide the numbers of the objects to track. The template matching of objects regions makes the tracking more accurate. Experimental results demonstrate that the method can track multiple-object steadily in real-time with moving camera.
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Computer Engineering. 2012, 38(20): 136-139. https://doi.org/10.3969/j.issn.1000-3428.2012.20.035Combined with the information fusion technology, this paper proposes an analog circuit fault diagnosis method based on High Order Cumulant(HOC). It applies the sine excitation signal for measuring circuit, extracts original voltage and current signal from the output terminal of testing circuit, calculates its kurtosis and skewness as fault feature vector, inputs to improved Back Propagation(BP) neural network to diagnose fault. Experimental results show that this method has higher accuracy rate.
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Computer Engineering. 2012, 38(20): 140-143. https://doi.org/10.3969/j.issn.1000-3428.2012.20.036Aiming at the ineffectiveness of the precision and recall of the unsupervised identification of comment target in the Chinese product reviews, a new method of the comment target recognition is proposed. The integrality and stability of the comment target and their calculation methods are put forward to filter the uncommented words, and the confidence level is scheduled with the consideration of the characteristics of the comment target in comment text, namely, its comment phrase rule and high occurrence frequency. Experimental results show that for the 14 799 digital comments, the precision, recall and F value reach 0.605, 0.780 and 0.681.
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Computer Engineering. 2012, 38(20): 144-147. https://doi.org/10.3969/j.issn.1000-3428.2012.20.037An algorithm based on adaptive chaotic Particle Swarm Optimization(PSO) is put forward to overcome the problem of the premature convergence and low precision of PSO algorithm. This algorithm mixes adaptive weight, selection and variation operation of genetic algorithm and chaos algorithm. This can increase the species diversity of particles. The method of judging the local convergence is used to judge the particles statement. When the particles are in local convergence, the chaotic search method is used to guide the group out of local optima. Simulation results show that this algorithm not only can solve the local convergence problem effectively, but also can speed up the convergence rate and improve the search precision.
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Computer Engineering. 2012, 38(20): 148-151. https://doi.org/10.3969/j.issn.1000-3428.2012.20.038According to the signal recognition rate decided by recognition model and the characteristic parameters, this paper puts forward the fusion K-means clustering of the observed sequence Baum-Welch parameters estimation algorithm to train Hidden Markov Model(HMM), the Principal Component Analysis(PCA) is adopted to transform Mel Frequency Cepstrum Coefficient(MFCC) features. A heart sounds signal automatic diagnosis system is designed based on PCA and HMM. Experimental results show that the average recognition rate of 6 common classe’s heart sounds reaches 83.3%, the performance is better than other heart sound recognition systems.
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Computer Engineering. 2012, 38(20): 152-155. https://doi.org/10.3969/j.issn.1000-3428.2012.20.039Taking Condition Random Field(CRF) method as probability model for word sense disambiguation model base, this paper uses CRF to train model file of high-frequency meaning and low-frequency meaning. It analyzes the probabilities in the result, determines a threshold to justify whether the marked tag is right, and uses the best performed model and its corresponding threshold to build CRF model base. Experimental results prove that model files of low-frequency meaning have better performance. The accuracy rate can reach above 80%, and the call rate is high.
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Computer Engineering. 2012, 38(20): 156-159. https://doi.org/10.3969/j.issn.1000-3428.2012.20.040The existing facial expression recognition rate of facial expression feature extraction algorithm is low. For this, this paper proposes a facial geometric feature extraction algorithm based chain codes. Based on active shape model that locates feature points and outputs the points’ coordinates of facial targets the coding method gives a circular codes to extract the facial geometric feature. Experimental results show that, compared with the method of typical LBP expression recognition, the accuracy of the algorithm is increased by nearly 10%.
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Computer Engineering. 2012, 38(20): 160-163. https://doi.org/10.3969/j.issn.1000-3428.2012.20.041Based on analyzing the shortages of K-Nearest Neighbor(KNN) algorithm in solving classification problems on imbalanced dataset, a novel KNN approach based on weight strategy(GAK-KNN) is presented. The key of GAK-KNN lies on defining a new weight assignment model, which can fully take into account the adverse effects caused by the uneven distribution of training sample between classes and within classes. The specific steps are as follows: use K-means algorithm based on Genetic Algorithm(GA) to cluster the training sample set, compute the weight for each training sample in accordance to the clustering results and weight assignment model, use the improved KNN algorithm to classify the test samples. GAK-KNN algorithm can significantly improve the identification rate of the minority samples and overall classification performance. Theoretical analysis and comprehensive experimental results on the UCI dataset con?rm the claims.
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Computer Engineering. 2012, 38(20): 164-168. https://doi.org/10.3969/j.issn.1000-3428.2012.20.042This paper studies the problem with experimental approach. It also investigates the impact of number of hidden layer nodes to generalization performance of Single Hidden Layer Feedforward Neural Network(SLFNN). Experiment on Extreme Learning Machine(ELM) with 35 databsets is made. For different databases, the optimal number of hidden layer nodes with respect to best test accuracy is found, and the performance of SLFNN can be improved by randomly mapping the data into a fixed high dimensional space with ELM algorithm.
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Computer Engineering. 2012, 38(20): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2012.20.043For time-frequency characteristics of Fractional Fourier Transform(FRFT) and Local Binary Pattern(LBP) operator have advantages in extracting texture feature, this paper proposes to combine FRFT with LBP for recognizing smile emotion. It takes the amplitude information of transformed FRFT as facial feature, fuses LBP and discriminates smile with proper classification criterion. At the same time, the overall recognition rate and smiling face recognition rate are used to express experimental results. Compared with other methods, simulation results in RML expression database show that the method is effective for smile recognition.
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Computer Engineering. 2012, 38(20): 172-175. https://doi.org/10.3969/j.issn.1000-3428.2012.20.044This paper proposes an association recommend item generating and sorting method for comprehensive e-commerce based on time weighting. Mixture of vertical, horizontal data formats and hash technology are employed to obtain the recommended candidates efficiently. Improved Jaccard similarity coefficient with time factor is taken into calculation, meanwhile it combines with the degree of association for the candidates sorting to balances the diversity of recommendation and consumers’ preference. Application results show that this method has better performance in recommend-items generating efficiency and online recommending effect.
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Computer Engineering. 2012, 38(20): 176-178. https://doi.org/10.3969/j.issn.1000-3428.2012.20.045To meet the actual needs of Uyghur dialect speech synthesis, this paper gives priority to Kashgar dialect. Based on the comparison with text corpus, the paper comparatively analyzes the phoneme correspondence between the standard Uyghur language and Kashgar dialect, observes the changes like phoneme insertion, deletion and substitution phoneme, collects the corresponding rules for these changes, and constructs the finite state transducers for those conversion rules. Experimental results show that the automatic conversion algorithm based on rule has good performances.
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Computer Engineering. 2012, 38(20): 179-183. https://doi.org/10.3969/j.issn.1000-3428.2012.20.046This paper introduces a kind of Web page categorization technology through analysis of characters of users’ behavior, along with current hotspot of researching on Web pages categorization. Trough grasping users’ behavior and interest by analyzing the history of Web user’s access, and by concluding knowledge rules out also with pages’ characters distilled. It provides a kind of appropriate categorization pattern on Web pages based on users’ knowledge level, and surely improves classifying effect without language meanings understood contrast with pure statistic categorization. Experimental results indicate that this pattern of categorization combining kinds of statistic algorithm can improve accuracy of categorization, and make the classifying results more closer to real facts and people’s knowledge desire.
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Computer Engineering. 2012, 38(20): 184-187. https://doi.org/10.3969/j.issn.1000-3428.2012.20.047Image information contains a lot of uncertainty which may cause the unsatisfactory image segmentation effect. In order to solve this problem, this paper proposes a algorithm of color image segmentation based on granular computing and cloud model. It granulates color images in HSV color space, and cloud-granule concept is generated in multi-granularity and multi-level, finally the color image is segmented. Experimental results show that the proposed algorithm has better performance compares with PCNN and K-means algorithm.
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Computer Engineering. 2012, 38(20): 188-190. https://doi.org/10.3969/j.issn.1000-3428.2012.20.048Ordered dither halftone image is a special kind of binary image which has periodic massive texture. In view of this, a lossless compression algorithm for dither halftone images based on rectangular coding is proposed. Before the rectangular partition coding, the dither image is down sampling according to the size of dither template and XOR operation is taken as well aiming at changing the original feature that the black and white pixels are frequently alternated. Experimental results show that the algorithm has advantage in time efficiency.
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Computer Engineering. 2012, 38(20): 191-194. https://doi.org/10.3969/j.issn.1000-3428.2012.20.049In order to improve the image reconstruction quality, by studying the super-resolution image reconstruction technology and the theory of sparse representation, this paper proposes a super-resolution image reconstruction algorithm based on L1/2 regularization. It applies L1/2 regularization into dictionary learning, and reconstructs super-resolution images using learned dictionaries. Experimental results show that the reconstruction results in this paper are better than the results of super-resolution image reconstruction algorithm based on L1 regularization.
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Computer Engineering. 2012, 38(20): 195-196. https://doi.org/10.3969/j.issn.1000-3428.2012.20.050According to the influence by outside light environment, the color images collected often have color offset problems, so this paper uses a white balance correction algorithm. It adjusts the image strength of red, green and blue on the basis of the present image characteristic, to correct the error caused by external light. Thus it can solve the problems caused by light color offset to some extent, and make the examination result steadier by using the image of colorimetric method of image processing. It uses the binary image boundary tracking processing, and the histogram segmentation. Experimental result shows that this method has higher segmentation accuracy.
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Computer Engineering. 2012, 38(20): 197-199. https://doi.org/10.3969/j.issn.1000-3428.2012.20.051When transferring color from colorful image to grayscale image, a suitable source image is a key to succeed rendering. Thus, a color transfer method based on texture and color feature extraction is introduced in this paper. Features of texture and color are extracted as indexes, the texture similarity between source images and grayscale image is calculated to retrieve a similar source image to improve the color transfer, and the color feature is extracted to be used to select sample pixels from the source image to improve the rendering effect. Experimental results show that the method can improve the probability of color transfer with better performance.
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Computer Engineering. 2012, 38(20): 200-203. https://doi.org/10.3969/j.issn.1000-3428.2012.20.052Aiming at the Intravascular Ultrasound(IVUS) image with strong background noise and pseudo shadow interference, a novel method of automatic vessel wall edge detection for IVUS images is proposed. In the process of detecting edge, the noise can be reduced by using the spatial and temporal correlation among the sequences. The new regulatory factor and adaptive normal external force are introduced in the GVF-Snake model which not only enlarges the edge capture range and makes the extraction effect of the image more accuracy, but also improves the robustness of the active contour to noise. It uses cubic B-spline to enhance the edge smoothness, and speeds up the convergence. Experimental results demonstrate that the method has higher accuracy and shorter running time.
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Computer Engineering. 2012, 38(20): 204-208. https://doi.org/10.3969/j.issn.1000-3428.2012.20.053To enhance the performance of texture image retrieval, a new method based on statistical model is presented. It proposes a color texture retrieval method using Pyramidal Dual-tree Directional Filter Bank(PDTDFB) decomposition to gain multi-scales and multi-directions sub-bands information. For extracting feather from sub-bands coefficients and measuring similarity, the Gamma distribution and KL distance are provided. Experimental results from VisTex texture images database show that the average retrieval rate of proposed method is higher than DT-CWT method.
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Computer Engineering. 2012, 38(20): 209-211. https://doi.org/10.3969/j.issn.1000-3428.2012.20.054Aiming at the contradiction between the quality of image reconstruction and the quantity of coefficient sampling, the Compress Sensing(CS) algorithm based on the wavelet transform is proposed in this paper. It discusses the sparsity of image coefficient after multi-scale transform. The high-pass wavelet coefficients of the image are measured and the low-pass wavelet coefficients are preserved. The Orthogonal Matching Pursuit(OMP) algorithm is used for reconstruction of compress sensing. Simulation result demonstrates that the proposed algorithm can improve the quality of the recovered image significantly.
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Computer Engineering. 2012, 38(20): 212-214. https://doi.org/10.3969/j.issn.1000-3428.2012.20.055This paper proposes a 3D visualization method of mine monitoring data based on color gradual interpolation for solving the problems on insipidity of mine monitoring data and difficulty of incompletion of expressing monitoring data information. The monitoring data is divided into several layer levels, and the data of each layer level is changed into a gray value, then the gray value is mapped to the color space according to the color coding. Neighboring synusia in false color image is processed on smoothing transition on the basis of method of color gradual interpolation. Experimental results show that this method can make the layer level of false image color enhanced, smooth the color transition and benefit the express of the information of mine monitoring data.
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Computer Engineering. 2012, 38(20): 215-218. https://doi.org/10.3969/j.issn.1000-3428.2012.20.056Because there is not normal communication protocol for RS485 bus network, a fast and steady communication protocol is designed. This paper introduces the method of creating the RS485 bus network and a detailed design of communication protocol for RS485 bus network. A simple and efficient conflict processing method is proposed with special reference to CSMA/CD protocol. The communication protocol is implemented and tested on ARM7, ARM9 and DE2-70 embedded development platforms with uC/OS, Linux or VxWorks operating systems. Experimental results show that this communication protocol meets the technical requirements in terms of versatility, stability, real-time and scalability aspects.
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Computer Engineering. 2012, 38(20): 219-223. https://doi.org/10.3969/j.issn.1000-3428.2012.20.057Underground substation auxiliary systems are characterized as varieties of equipment, complex control types, complicated associated relationships. This paper makes use of XML language to model entire simulation system, stratified design method to implement man-machine interaction, and standard SQL database to design external data interface among various subsystems. Against the characteristics of underground substation auxiliary system, it designs and implements a vivid simulation of control background of auxiliary system and daily inspections, operation and accident handling simulation content. Application results show that the system has good scalability and maintainability.
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Computer Engineering. 2012, 38(20): 224-227. https://doi.org/10.3969/j.issn.1000-3428.2012.20.058In order to guarantee the rail transit operation safety, improve efficiency of emergency response and maintenance when an accident happens, this paper proposes constructing the P2P network based publish/subscribe system of the rail transit data and transmitting data and information to the subscriber of which subscription filter matches the published event. The control center in publish/subscribe system pushes power system data to network nodes, when there is a failure of power system, maintenance personnel can timely obtain the fault alarm, power system information and on-site environmental parameters by subscribing to the network system. During the period of the system failure, the parallel execution of the repair program can be executed. Application results show that publish/subscribe system effectively improves the response rate and maintenance efficiency of rail transport failure.
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Computer Engineering. 2012, 38(20): 228-231. https://doi.org/10.3969/j.issn.1000-3428.2012.20.059A general auto dashboard detection platform is developed for lack of integration, versatility and several other problems in the current dashboard detection platform, which can detect the accuracy of display data as well as the working condition of other digital signal indicators in CAN bus and ordinary auto dashboard. Virtual instrument based on VC++6.0, CAN bus, dashboard statement comparison, and other technology and methods are used in the detection platform. By the actual detection for CAN bus and ordinary auto dashboard, results show that the test platform has great integration and versatility.
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Computer Engineering. 2012, 38(20): 232-235. https://doi.org/10.3969/j.issn.1000-3428.2012.20.060The track circuit performs the strategy of fault and planned maintenance until now. In order to overcome the defect of this strategy, this paper presents a state-based mechanism for predictive maintenance of equipment, and designs a kind of architecture and workflow for Prognostics and Health Management(PHM) technology. A PHM system for High-voltage Asymmetric Pulse(HVAP) track circuit is designed based on fuzzy neural network, and two input parameters and four output typical faults are set in this system, the output faults are described with credibility, and the fuzzy inference rule table is gotten according to the expert knowledge and the experience from field. Computer simulation results show that the architecture of PHM is effective.
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Computer Engineering. 2012, 38(20): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2012.20.061This paper puts forward an Architecture Analysis and Design Language(AADL) modeling tool to help AADL users establish AADL models. Based on Model Driven Architecture(MDA), this paper describes the development procedure of this tool in Eclipse IDE which is an extensible plug-ins set. AADL models built in this tool by users can be saved in XML format which maks it convenient for analysis and verification tools to obtain AADL models as a third-party plug-in. A case shows the validity of this tool.
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Computer Engineering. 2012, 38(20): 239-242. https://doi.org/10.3969/j.issn.1000-3428.2012.20.062Aiming at the problem of high costs, single target and fixed test methods of traditional test architecture of NC whole machine tools dynamic performance, a new architecture is proposed to reduce costs and extend test targets and analysis methods by adopting the object/relation mapping and plugin technology which are based on reflection. Based on the architecture, test methods, including spindle test, equability test, circularity test and universal axis test, are implemented for Sinumerik 840D series NC system. Integrity and effect of system are proved by a group of contrast experiments.
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Computer Engineering. 2012, 38(20): 243-246. https://doi.org/10.3969/j.issn.1000-3428.2012.20.063It is unfair, ineffective to access shared memory for multi-thread on the chip of multi-core. This paper proposes fairness-aware shortest job first scheduling which sets request for the maximun waiting time to guarantee fairness, uses shortest job first priority to cut down the average waiting time, pays attention to parallelism of threads to solve above problems. Experimental result shows that this method improves IPC performance in multi-thread visit, and the highest performance improvement can reach 43%.
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Computer Engineering. 2012, 38(20): 247-250. https://doi.org/10.3969/j.issn.1000-3428.2012.20.064In order to segment the bullet appearance color detect quickly, automatically and accurately, a new method of image segmentation is proposed based on hybrid color model. The color feature detect is segmented, which is extracted and analyzed from image feature. Aiming at the shortcoming of image segmentation by RGB color model under the condition of strong illumination, convert the color model from RGB to HSI in the interesting region of image, the detect is segmented by H component further. The result of segmentation is optimized by mathematical morphology and evaluated by average segmentation rate and average deflection. Experimental result shows that this method has extrusive accuracy and robustness in the application of bullet surface defect segmentation.
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Computer Engineering. 2012, 38(20): 251-255. https://doi.org/10.3969/j.issn.1000-3428.2012.20.065A single module failure rate prediction method is proposed using regression model. Through converting polynomial regression model to multiple linear regression to solve parameter value, the prediction equation is acquired. Checking significance of equation and coefficient, a new equation of which the fitting effects are better is established. The new equation is verified through some types of module failure rate data obtained from network experiment. The result shows that the proposed model can be used as a supporting model in the decision-making of a single module failure rate prediction.
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Computer Engineering. 2012, 38(20): 256-259. https://doi.org/10.3969/j.issn.1000-3428.2012.20.066How to provide high quality Geographic Information System(GIS) services under resource constraints on mobile devices, the system architecture and structure of a mobile GIS engine is analysed and designed. Using the A* algorithm to solve the problem of searching for optimal/shortest path in GIS. Through achieving an internal hierarchy of the engine, combining with position of mobile GPS and digital map technology, a mobile GIS engine system is achieved based on the Windows mobile platform using VC++. Studies show that the engine system interface is clean, well-functioning, and the search efficiency of A* algorithm is increased by 15%~20%.
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Computer Engineering. 2012, 38(20): 260-263. https://doi.org/10.3969/j.issn.1000-3428.2012.20.067According to the problem of slow retrieval in specific audio retrieval under the conditions of large template library, this paper proposes a two-stage specific audio retrieval method based on template-subspace. Utilizing the characteristics of a certain correlation among the same or similar templates, this method uses the method based on template-subspace to choose candidate template set of high similarity, and retrieves all the templates in the candidate set precisely to get the final result. Experimental results show that, compared with existing algorithms, this method can significantly improve the retrieval speed in the case of almost no loss of precision.
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Computer Engineering. 2012, 38(20): 264-267. https://doi.org/10.3969/j.issn.1000-3428.2012.20.068Traditional point cloud denoising algorithm can weaken the surface characteristics. In order to solve it, a denoising algorithm for point model surfaces is proposed based on orthogonal projections constraint. Orthogonal projection based on the moving least squares algorithm, according to the relationship between the point model and the projection onto the moving least squares, the moving distance weighting function is constructed. In order to avoid shrinkage, a new curvature weighting function is presented. By applying bilateral filtering algorithm to filter the normal, and in combination with the two weighted factors. The position offset of the point model is obtained. Experimental results show that the algorithm can denoise the noise efficiently while preserving the high-frequency features of the surface, and can avoid shrinkage and point drifting.
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Computer Engineering. 2012, 38(20): 268-271. https://doi.org/10.3969/j.issn.1000-3428.2012.20.069To overcome the fuzziness, inconsistency and limitation in Cut Sequence Set(CSS) model for dynamic fault tree, this paper proposes a quantification method of cut sequence set model based on temporal failure logic. It gives three tense failure logics, including priority failure logic, sequential failure logic and spares failure logic. Using temporal failure logic, it designs an unified quantitative method of different tenses failure logic. Example results show that this method is accurate, convenient, and easy to operate.
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Computer Engineering. 2012, 38(20): 272-274. https://doi.org/10.3969/j.issn.1000-3428.2012.20.070The generality of existing priority inversion inhibition model is poor, and the method is difficult to choose the value of priority ceiling. In order to solve this problem, this paper proposes an improved priority inversion inhibition model. By setting independent serving queue for kinds of scarce resource and excluding them from the queuing model of priority scheduling queue, parallel processing of multiple scarce equipments can be achieved within an embedded system with only single processing core and the probability of the priority inversion can be reduced. Simulation results show that the probability of priority inversion is about 1‰.
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Computer Engineering. 2012, 38(20): 275-277. https://doi.org/10.3969/j.issn.1000-3428.2012.20.071A video quality assessment model is proposed to improve the correlation with opinion score. Based on the human visual with different sensitivities in the frequency domain, with approximation coefficients and detail coefficients of wavelet transform, low frequency error and high frequency error of frame are calculated by different methods. The product of two errors is adopted as frame objective evaluation of quality. The overall quality of the entire video is given by the average of all frames measurement. Experimental results show that the method is competitive with state of the art quality assessment methods and has good correlation with perceived video quality.
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Computer Engineering. 2012, 38(20): 278-281. https://doi.org/10.3969/j.issn.1000-3428.2012.20.072Considering the Quality of Service(QoS) controlling question in the mobile computing environment, this paper designs a mobile service computing model including layer of the environmental awareness, middle level and sever level. The use of the reflecting technology checks the resource situation of the server in the application of the programme. In accordance with the predetermined stratigic dynamic to adjust systematic resources, it can comply with specific resource demands. Experimental results show that the model can make client achive more server resources in the case of high capacity and reduces responding time effectively, and be suitable for limitation of the mobile equipments.
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Computer Engineering. 2012, 38(20): 282-285. https://doi.org/10.3969/j.issn.1000-3428.2012.20.073Current deadline assignment schemes which adjust relative deadlines to reduce the output jitter of periodic real-time tasks are all under EDF(Earliest Deadline First) scheduling algorithm. In this paper, a static priority assignment problem to minimize the total output jitter of a set of real-time tasks is proposed. A heuristics algorithm is presented to solve this problem. It assigns the initial priority to each task according to RM(Rate Monotonic) algorithm, and adjusts the priority of each task one by one in terms of minimizing the sum of local output jitter, until a near optimal solution to the static priority assignment problem is found. Simulation results show the advantages of the algorithm in terms of reducing the total output jitter of a set of tasks and computing complexity.
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Computer Engineering. 2012, 38(20): 286-289. https://doi.org/10.3969/j.issn.1000-3428.2012.20.074To solve the problem that LIRS algorithm has the shortage of complex structure and poor adaptability, this paper proposes an Adaptive Clock algorithm based on LIRS algorithm. Adaptive Clock algorithm absorbs the Clock algorithm ideas to simplify the organizational structure of the algorithm to improve the adaptability of different data access patterns, as to enhance the ability to capture high-frequency data. Experimental results show that Adaptive Clock has better performance in hit rate than LIRS algorithm and two commonly used algorithms, and meets the requirements of the high Cache replacement ratio and less computing resource.
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Computer Engineering. 2012, 38(20): 290-292. https://doi.org/10.3969/j.issn.1000-3428.2012.20.075So far, there are many ways used for analyzing Reliable User Datagram Protocol(RUDP), but it lacks a formal model. For this problem, this paper puts forward a formal model for RUDP with Colored Petri Nets(CPN) and using the CPN tools to realize the model and simulate it. The verification of various properties of the protocol model is achieved by means of a state space report produced by the tool. The average retransmission rate is gotten about 5% by three different kinds of tests. The model can basically imitate the behaviors of the RUDP, and gives a formal method to research the RUDP.
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