20 March 2011, Volume 37 Issue 6
-
Select all|
-
Computer Engineering. 2011, 37(6): 35-37. https://doi.org/10.3969/j.issn.1000-3428.2011.06.013This paper proposes one K-level nodes technique of Web application test suite reduction based on user session and concept analysis. On the basis of reduction analysis, it designs an incremental update algorithm of test suite. The algorithm mainly updates or adds nodes to the original concept analysis according to the comparison between the new and existing nodes. Through a small Web login system, the paper shows the effectiveness of the technique.
-
Computer Engineering. 2011, 37(6): 38-40. https://doi.org/10.3969/j.issn.1000-3428.2011.06.014Compared with traditional algorithms for merging a set of polygons, the cascaded union algorithm is more efficient by merging adjacent polygons first based on STR-Tree. However, it has poor performance in high distortion area of data density. To solve this problem, a cascaded union algorithm for polygon set based on grid is proposed. It spilts polygon set by using grid, which can reduce the high distortion area of data density. Experimental results show that the algorithm is feasible and effective.
-
Computer Engineering. 2011, 37(6): 41-43. https://doi.org/10.3969/j.issn.1000-3428.2011.06.015Aiming at the problem that the Reliability of Evidence Source(RES) is only derived from objective evidences but ignoring the subjective cognitively information such as knowledge, experience or intuition in RES reasoning and evidence combination, this paper introduces the RES objective matrix and the RES subjective matrix to reflect the objective and subjective RES information based on evidence distance and pair- wised judgment matrix. An integrating RES model for deriving overall RES information is established by minimizing the whole adjusting errors, and evidence reasoning steps are proposed by using Dempster combination rules. Numerical value example proves the feasibility of this method.
-
Computer Engineering. 2011, 37(6): 44-45. https://doi.org/10.3969/j.issn.1000-3428.2011.06.016This paper proposes a new fuzzing technique based on input path tracking technology on disassembly code, which is combined with code-coverage-based test data generation and snapshot-recovery-based fault injection techniques. It is a new method for automatic software security vulnerability discovering and solves a number of limitations of traditional fuzzing techniques. A test system based on this method is designed and implemented and the method is validated by vulnerabilities discovering experiment on example software.
-
Computer Engineering. 2011, 37(6): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2011.06.017It is very difficult to use OOF because the sizes of the frameworks are often large and many of the existing frameworks suffer from the lack of proper manuals and documentation. This paper proposes the concept of Maximum Sharing sub-Edge Tree(MSET). Based on MSET, it gives an algorithm for mining the framework hot-spot instantiation pattern.
-
Computer Engineering. 2011, 37(6): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2011.06.018TASC model can solve the cooperation trust crisis result from the phenomenon that it is difficult to predict and control the autonomy individual behavior. Under this model, service contract establishes cooperation relations between Agents. This paper proposes an effective service contract generation method. It uses service classification system, service discovery mechanism for scenario and service contract protocol template, generates contract in a fast and reusable way, thus improve the level of automation, and gives the process of trust autonomy service cooperation and service contract automatic generation.
-
Computer Engineering. 2011, 37(6): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2011.06.019Single Web services can not meet the needs of practical applications, how to compose existing services to form new services has become an important research in Web service domain. Current composition methods seldom consider the possible semantic similarities between their pre and post-conditions. To improve the situation, this paper presents a Web service composition approach based on goal narrowing. By introducing the use of a conditional directed acyclic graph, the approach can deal with complex interactions, containing control flow, information flow and pre/post conditions. Through a concrete example applying the approach to search for the service chain, the paper shows the effectiveness of the approach.
-
Computer Engineering. 2011, 37(6): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2011.06.020This paper proposes an Agglomerative Information Bottleneck based Weighted Hierarchical Clustering algorithm(ABWHC) to rebuild the architecture of object oriented software. ABWHC uses information loss as the similarity measure, considers the characteristics of object oriented software by extending clustering features and weights, and generating label group for each entity or cluster. Experimental results demonstrate that ABWHC improves the performance of clustering, and efficiently and flexibly achieves object oriented software architecture recovery.
-
Computer Engineering. 2011, 37(6): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2011.06.021
This paper describes how to collect and use the invariant information of a variable in GCC. The optimization performance is evaluated using NPB benchmark. It proves that compiler optimizes and improves program performance based on the value profiles, but the effects of value profiling based optimizations are quite different between different programs. It shows that there are further improvements, such as value profiling information or optimization type, etc.
-
Computer Engineering. 2011, 37(6): 61-64. https://doi.org/10.3969/j.issn.1000-3428.2011.06.022In order to quickly and effectively mine the 3D data set of the closed frequent itemsets, the paper proposes a data mining algorithm based on bitwise-based processing technology for 3D dataset——Bitwise-Data-Peeler(BD-Peeler). The algorithm makes the best use of the computer processing 32-bit data each time. The 3D data sets are stored by bits, so that it can increase the computational data each time in the 3D dataset. Experimental results show that it can quickly and efficiently mine the 3D data set of the closed frequent itemsets.
-
Computer Engineering. 2011, 37(6): 65-67. https://doi.org/10.3969/j.issn.1000-3428.2011.06.023Extraction rule plays an important role in Web information extraction based on wrappers. As the Web pages often change, the rule is updated frequently. However, it is a hard work to find extraction rule by hand. This paper proposes an auto extraction rule generation method, which constructs a semantic TABLE tree after scanning HTML code. The semantic TABLE trees is used to identify the data table, and the extraction rule is generated automatically through a greedy algorithm. Experiment result shows that it has high precision and F-score, and has high rule generation rate to the identified table.
-
Computer Engineering. 2011, 37(6): 68-70. https://doi.org/10.3969/j.issn.1000-3428.2011.06.024For non-rule cycle structure, the different OpenMP schedule strategy effects are analyzed on the basis of the analysis and different predefined OpenMP schedule strategy performance is assessed. The defect of the existence of schedule policies is analyzed and then a suitable non-rule cycle of the structure of balanced schedule algorithm Balance is designed to realize payload balance of no-rule balancing loop schedule. Test results show that the schedule algorithm is effective.
-
Computer Engineering. 2011, 37(6): 71-73. https://doi.org/10.3969/j.issn.1000-3428.2011.06.025This paper proposes a pointer data prefetching method for the memory wall problem——pure traversal push mechanism. It utilizes multi-threading technology based on CMP, and dispatches a helper thread when the program runs which prefetches the demanded data into the shared cache in advance to hide the long memory access latency. Experimental results show that the pure traversal push mechanism improves the performance of pointer-chasing and memory intensive applications apparently.
-
Computer Engineering. 2011, 37(6): 74-76. https://doi.org/10.3969/j.issn.1000-3428.2011.06.026
To solve the problems of the cumbersome operation of node join and large ineffective scanning in XML path query, a new method of Schema-based XML index method is proposed. The XML is determined, which need to be scanned by matching Schema and query path. Code method is used to reduce the times of nodes connection. Experimental results demonstrate that this method achieves higher efficiency, better operability and expansibility than previous methods.
-
Computer Engineering. 2011, 37(6): 77-78. https://doi.org/10.3969/j.issn.1000-3428.2011.06.027
Quick sort works fairly efficiently contrasting with other sort algorithms, but it has choke point when sorted data are in order or basically in order. This paper brings forward a new high efficient quick sort algorithm comparing with several algorithms whose performances are O(nlbn). And on theory analysis as well as experiment data, it proves fairly good sort performance and strong robustness even in case of data sorted or basically in order comparing with other sort algorithms.
-
Computer Engineering. 2011, 37(6): 79-81. https://doi.org/10.3969/j.issn.1000-3428.2011.06.028
This paper presents a web crawler fitting for RSS which uses breadth-first algorithm and focuses on RSS to carry out automatically collection. And based on word segment, it improves the method to calculate word weight, works on word filtering, and implements automatically classification aiming at RSS using VSM. Experimental result shows that the system achieves to retrieve and classify Chinese RSS information with lower system cost and higher accuracy. And it can take manage of RSS information syndication effectively.
-
Computer Engineering. 2011, 37(6): 82-84. https://doi.org/10.3969/j.issn.1000-3428.2011.06.029Because the formal analysis of Border Gateway Protocol(BGP) is rare, a hierarchical model of connection process between two routers based on Colored Petri Net(CPN) is put forward according to RFC 1771. Through interactive simulation, the deviation between behavior of the proposed model and expected behavior can be observed. The proposed model should be tuned until all behavior deviations disappear. The state space of the model is calculated to validate the properties of no-deadlock and fairness.
-
Computer Engineering. 2011, 37(6): 85-87. https://doi.org/10.3969/j.issn.1000-3428.2011.06.030This paper gives an traffic-adaptive MAC protocol based on dynamic duty cycle. Based on S-MAC and TDMA traffic-adaptive MAC protocol, it introduces the dynamic duty cycle mechanism, the original listening/sleep cycle of S-MAC protocol is divided into several short listening/sleep cycles to transmit data repeatedly. Simulation results show that the protocol can effectively lower system delay, maintain higher throughput and achieve smooth switch of protocols when the number of contenders changes.
-
Computer Engineering. 2011, 37(6): 88-90. https://doi.org/10.3969/j.issn.1000-3428.2011.06.031The standard Mobile IPv6(MIPv6) fast handoff scheme is analyzed. A neighbour information table-based fast handoff scheme for MIPv6 is proposed. Through pre-configured and regularly updated way to let Mobile Node(MN) get ahead of target limited areas of information table, called neighbour information table. It switches process with a neighbour information table to shorten the uniqueness of the care-of address verification and testing of time delay, reduce the packet loss rate in the handover process. Simulation results show this mechanism does not take up additional network resources. It reduces the packet loss rate and cuts down the switching process of switching delay time.
-
Computer Engineering. 2011, 37(6): 91-93. https://doi.org/10.3969/j.issn.1000-3428.2011.06.032Opportunistic data dissemination is an important issue in opportunistic networks while meta-data exchange is a way to enhance the performance of data dissemination. Known Vector(KV) is proposed as one of the solutions to meta-data exchange. However, the meta-data synchronization is far from satisfaction when the size of the buffer is finite. To solve the problem, an improved approach, called Dynamic Known Vector(DKV), is proposed in this paper. Besides the advantages of KV, DKV self-describes the reliability of the exchanged meta-data and has the prediction capability. Experiments show that, when finite buffer is applied, DKV improves the synchronization exhibited in KV and decreases the average message delivery time, hence improve the data dissemination in opportunistic networks.
-
Computer Engineering. 2011, 37(6): 94-96. https://doi.org/10.3969/j.issn.1000-3428.2011.06.033The mathematical model of non-sinusoidal orthogonal modulation in time domain based on Prolate Spheroidal Wave Functions(PSWF) is proposed and the fundamentals are discussed. The mathematical expressions of the data rate-to-bandwidth ratio, the spectrum of modulated signals and the bit-error-rate in Additive White Gauss Noise(AWGN) channel are deduced and the system performance is simulated. Simulation results are compared with the mathematical ones and the theoretical derivation is proved. Results can provide theoretical and practical basis for communication system design.
-
Computer Engineering. 2011, 37(6): 97-99. https://doi.org/10.3969/j.issn.1000-3428.2011.06.034Aiming at the problems in the terminal abnormal exit under the CMIP in the existing schemes of exit in the WiMax network architecture standards, this paper introduces WiMax standard architecture and Mobile IP(MIP) protocol. Existed terminal exit and resource releasing in CMIP/PMIP patterns are researched. A solution that the decision-making power for the detection of terminal abnormal exit and the launch of exit processes given to the Network Access Gateway(ASN-GW) is presented. Design and implementation of the solution indicate that the solution not only can solve the problems that it can not release resources timely or charge for properly under the CMIP mode, but also is suitable for the terminal normal exit and abnormal exit under the PMIP mode.
-
Computer Engineering. 2011, 37(6): 100-103. https://doi.org/10.3969/j.issn.1000-3428.2011.06.035This paper formulates a class of Network Utility Maximization(NUM) problem for coded multicasts, which incorporates constraint used to stabilize sender’s packet buffer and intermediate node’s queue. Based on primal and primal-dual form of the problem, it proposes two congestion control models for network coding, whose stability is demonstrated through Lyapunov criteria. The models are entirely distributed feedback control systems. The corresponding algorithms can handle network dynamism with only end-to-end information exchange, and have the form of TCP-like congestion control, showing their compatibility with current network architecture.
-
Computer Engineering. 2011, 37(6): 104-106. https://doi.org/10.3969/j.issn.1000-3428.2011.06.036In order to solve the problems in current work that relies on well known TCP or UDP port numbers or interpreting the contents of packet payloads, such as low accuracy and limited application region. This paper proposes a method based on a Supervised Self-Organizing Maps (SSOM) network classification method for traffic classification. The method uses training dataset of network traffic which has been labeled the traffic classes, and changes the adaptation rule of weighs in SOM training process, which easier to choose the winning neuron of output layer and divides each class more clearly, and improves the performance of classification. Experimental results show the SSOM network algorithm has a better resolution and a more continuous mapping than SOM. Its applying to network traffic classification has a higher accuracy rate.
-
Computer Engineering. 2011, 37(6): 107-109. https://doi.org/10.3969/j.issn.1000-3428.2011.06.037
The scarcity of available channels and radios per node in the Wireless Mesh Network(WMN) limits the bandwidth available on the links of the multicast tree and eventually cuts the network throughput down. Aiming at this problem, this paper proposes a channel assignment algorithm for multicast in multi-channel multi-radio WMN called LAMCA. It can minimize the interference of multicast tree and improve the network throughput. Simulation results show that the algorithm can further optimize the throughput performance by comparing with the LCA algorithm.
-
Computer Engineering. 2011, 37(6): 110-112. https://doi.org/10.3969/j.issn.1000-3428.2011.06.038This paper proposes a kind of cipher processing technology based on Synchronous Data Triggered Architecture(SDTA), which makes use of the characteristics of SDTA such as high parallelism, high adaptability and polymorphism to meet the demands of high performance, strong adaptability and anti-attacking. Its design and optimization flow is used to analyze the applications to get the bottleneck operations, and the corresponding processing units are designed to accelerate the specific applications. The new designed units are easy to be added to the SDTA core, which helps to reduce the design time.
-
Computer Engineering. 2011, 37(6): 113-115. https://doi.org/10.3969/j.issn.1000-3428.2011.06.039This paper presents a blind watermark algorithm of multi-wavelet domain based on neighborhood and FCM. The watermark embedding texture sub-blocks are obtained adaptively on the multi-wavelet domain middle-frequency coefficients by applying FCM based on the human visual system. A binary image is embedded to texture sub-blocks, this algorithm can get a watermarked image with perceptual invisibility and strong robustness. In order to improve the security and robustness, the watermark is scrambled before embedded, and is repeated when embedded. Experimental results show that the algorithm is strongly robust for the common image processing techniques such as JPEG compression, cropping, sharpening salt and pepper noise, filtering and so on.
-
Computer Engineering. 2011, 37(6): 116-117. https://doi.org/10.3969/j.issn.1000-3428.2011.06.040
This paper presents a CL-PKC-based secure protocol for sharing trust data in unstructured P2P networks protocol. The short response time and overhead of protocol can effectively improve the efficiency of the trust assessment. The public/private keys are generated by the key generator center. The security, integrity and non-repudiation of messages are guaranteed by these keys. The strand space theory proves the security of protocol.
-
Computer Engineering. 2011, 37(6): 118-120. https://doi.org/10.3969/j.issn.1000-3428.2011.06.041General attestation protocol relies entirely on platform configuration, and it fails when platform updates software and hardware configuration frequently. To overcome the problem, this paper presents an improved property-based attestation protocol scheme, employing cryptographic tools such as non-malleable zero-knowledge protocol, commitment protocol and blind signature scheme. Analysis proves that the protocol can solve the exiting problem with better security, while computing cost only increases by a negligible amount.
-
Computer Engineering. 2011, 37(6): 121-123. https://doi.org/10.3969/j.issn.1000-3428.2011.06.042This paper presents a method which extends instruction set for Advanced Encryption Standard(AES) on MIPS32 4k series using SIMD technology. Taking advantage of the align stage of processor pipeline and the dedicated AES data access engine, it realizes the parallel processing with 64 bit data width. It compares the performance of different implementation and the results show that the ISE boosts the performance of cryptographic algorithm, and the hardware cost is relatively low. It also has the programming flexibility.
-
Computer Engineering. 2011, 37(6): 124-126. https://doi.org/10.3969/j.issn.1000-3428.2011.06.043This paper proposes a construction method for second-order concatenation. By choosing the proper parameter s, the degree and algebraic immunity are increased by one when two variables are added. It increases the nonlinearity effectively while holding the resiliency of the Boolean function. Based on the method, a class of functions with optimal algebraic immunity is constructed with better nonlinearity, and a class of function with at least suboptimal algebraic immunity is derived which has one-order of resiliency and good nonlinearity. The recursive method is used for constructing the cryptographic good Boolean functions.
-
Computer Engineering. 2011, 37(6): 127-129. https://doi.org/10.3969/j.issn.1000-3428.2011.06.044In present adaptive ant clustering algorithms, the values of adaptive parameters are adjusted by experience, which affects clustering quality. To solve the problem, this paper proposes an improved method by using fast Simulated Annealing Algorithm(SAA) to realize dynamic adjustment of ant clustering adaptive parameters. An intrusion detection system based on the algorithm does not require pre-specification of the number of clusters, or that the number of normal behaviors is far greater than the number of intrusions. Simulation results on KDD CUP1999 dataset show that the algorithm can get better clusters, and has better detection effects on unknown intrusions.
-
Computer Engineering. 2011, 37(6): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2011.06.045In terms of scale-free networks’ properties, this paper proposes edges immunization strategy. The strategy can keep better connectivity than the targeted strategy. Using the susceptible-infectious-susceptible epidemic spreading model, it demonstrates the effectiveness of the proposed strategy on BA scale-free and HEP network. Experimental results demonstrate that the immunization uses less immunization doses and can control epidemic spreading effectively.
-
Computer Engineering. 2011, 37(6): 133-134. https://doi.org/10.3969/j.issn.1000-3428.2011.06.046
The disclosure of the number of votes can compromise the voters’ anonymity of the electronic voting. Aiming at this problem, this paper defines anonymity by using the uncertainty of the voting choices and measures the anonymity of the whole voting system by entropy. It compares the anonymity after the release of the voting results with that before releasing the voting results. Analysis result shows that the smaller the voting scale is, the more the voters’ anonymity loses. In the design of small-scale electronic-voting scheme, releasing the winner instead of the number of votes that candidates gained decreases the loss of anonymity.
-
Computer Engineering. 2011, 37(6): 135-137. https://doi.org/10.3969/j.issn.1000-3428.2011.06.047In order to realize Elliptic Curve Methods of factorization(ECM) on Graphic Processing Unit(GPU), this paper uses Montgomery curve spot coordinate expression to implement the ECM of large number with length of 112 bit on GeFore9800GTX+ card parallel. Its speed can achieve 1 251 curves per second with bound 8 192 in the first stage confirms. The implementation provides an experimental support to the factorization of surplus factors in NFS of RSA768.
-
Computer Engineering. 2011, 37(6): 138-140. https://doi.org/10.3969/j.issn.1000-3428.2011.06.048Authentication protocol based on the symmetric key demands the both communicators share the same key, and there is safety problem in the updating of the shared key. In order to solve the problems, this paper proposes a scheme which can register the graphical passwords with digital envelope. It resolves the key update with key establishment based on Identity-Based Encryption(IBE), and resists shoulder surfing adopting dynamic graphical sequence. Users can choose graphical passwords freely. Analysis result proves that the scheme can resist common attacks like replay attack effectively, and its communication cost is reduced.
-
Computer Engineering. 2011, 37(6): 141-144. https://doi.org/10.3969/j.issn.1000-3428.2011.06.049This paper proposes a novel trajectory-analysis-based performance evaluation method, which assesses and compares the navigation performances by reward settings and feature expectations under Markov Decision Process(MDP) framework. Assuming that the reward function is a linear combination of known features, this method evaluates reward settings by approximating the driving styles of different land autonomous navigation systems. On this basis, reward settings are used to simulate the feature expectations of navigation trajectories in a standard land navigation environment called the sandbox. Experimental results show the validity of this method in both qualitative and quantitative performance evaluations.
-
Computer Engineering. 2011, 37(6): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2011.06.050Aiming at the shortages of low efficiency, computational complexity and accuracy not high in traditional video text detection method, this paper presents a video text detection method based on sparse representation classification. It utilizes edge intensity and connected-components analysis algorithm to get raw text lines, and verifies them with non-complete dictionary generated by sparse presentation classification. Experimental results show that this method has better detection performance, and it can be applied to video classification and retrieval system.
-
Computer Engineering. 2011, 37(6): 148-150. https://doi.org/10.3969/j.issn.1000-3428.2011.06.051The recognition accuracy of the traditional biometric secure system is often influenced by the environment and physiological, and it leads to the development of the multimodal biometric systems. This paper presents a multi-modal biometric recognition system based on face and iris feature level fusion. Face and iris texture feature extraction is adopted Center-Symmetric Local Binary Pattern(CS-LBP) operators, the feature vectors that are extracted from face and iris are integrated linearly to form a mixed feature vector, and then Adaboost algorithm is used to select and aggregate the effective features from the mixed feature vector to build the strong classifier. Experimental results show that the system has better robustness than the mono-modal system.
-
Computer Engineering. 2011, 37(6): 151-152. https://doi.org/10.3969/j.issn.1000-3428.2011.06.052
Aiming at poor robustness of the threshold auto-selection algorithm in far-infrared images segmentation, an improved K-means clustering centers analysis algorithm based on the mechanism of far-infrared imaging is researched in this paper. According to the character that the cluster centers had a linear distribution before clustering and had a clear turning point after clustering when they belongs to different categories, the absolute difference between the practical cluster centers value and theoretical cluster centers predicting value of a category under test is taken as the measurement function to select the turning point, thus the threshold for image segmentation was determined. Experimental result shows good robustness and anti-noise performance of the algorithm.
-
Computer Engineering. 2011, 37(6): 153-156. https://doi.org/10.3969/j.issn.1000-3428.2011.06.053In this paper, a new algorithm for extracting the instantaneous amplitudes of the intercepted signals is proposed in order to automatically recognize the modulation types of MASK, MFSK, MPSK and MQAM signals. This algorithm has no need of Hilbert transformation or symbol synchronization. On the basis of this, seven feature parameters and a modulation recognition algorithm of the aforementioned four types of signals are derived. Simulations result shows that the average modulation recognition success rate is≥97% at Signal-to-Noise Ratio(SNR)≥8 dB. It proves that the new algorithms for both the instantaneous amplitude extracting and the modulation recognition are efficient and can be used in practical online analysis.
-
Computer Engineering. 2011, 37(6): 157-158. https://doi.org/10.3969/j.issn.1000-3428.2011.06.054
It usually exists bias when existing Support Vector Data Description(SVDD) algorithm solves the problem of imbalanced data sets. Aiming at this problem, this paper proposes FE-SVDD algorithm with improved imbalanced data classification. The feature extraction method based on Principal Component Analysis(PCA) is introduced. In this algorithm, the principal values are found respectively of the two classes of samples by using PCA. The penalty is given based on the information provided by the sizes of the two sample data and their values. It verifies the C of SVDD algorithm using artificial data and UCI datasets for the data imbalanced classification problem. Experiment results on artificial data sets and UCI data sets show the method’s effectiveness.
-
Computer Engineering. 2011, 37(6): 159-161. https://doi.org/10.3969/j.issn.1000-3428.2011.06.055This paper provides an incremental Hessian LLE algorithm, using the inverse iteration with Ritz acceleration, which is capable of dealing with one or more new samples efficiently. The core idea of the algorithm is to translate an incremental manifold problem into an incremental eigen-value problem, and to solve it by the tools of numerical linear algebra. The analysis of its convergence is given. Experiments on both artificial and image datasets confirm the efficiency and accuracy of the proposed method.
-
Computer Engineering. 2011, 37(6): 162-164. https://doi.org/10.3969/j.issn.1000-3428.2011.06.056The search content of node Peer-to-Peer(P2P) users reflects the user interest. So this paper proposes a search mechanism based on keyword relationship and node interest. The mechanism learns focus on the relationship between keywords, finds node by user interest. The use of keywords in the search increases the target semantic relations, and improves the search success rate. According to the node of interest, it narrows search and reduces the search overhead. Experimental results show that the fast index table method and the feedback mechanism can effectively improve the search performance.
-
Computer Engineering. 2011, 37(6): 165-167. https://doi.org/10.3969/j.issn.1000-3428.2011.06.057
Locally Linear Embedding(LLE) algorithm is typically used to reduce dimensionality of high-dimensional manifold data. Though it has advantage such as a simple structure, being not easy to fall into local minimum value and preserving the same local geometric structure, the algorithm is sensitive to the noise points and singular value points. To solve this problem, this paper presents a locally hyperplane algorithm which can remove the singular value points. The algorithm projects each neighborhood of sample points onto the hyperplane space, so the projections of singular value points will be away from other projections that are aggregate in the neighborhood, and it finds all the points that are away from the gathering center in the neighborhood as singular value points. Simulation results verify the validity and effectiveness of the algorithm.
-
Computer Engineering. 2011, 37(6): 168-171. https://doi.org/10.3969/j.issn.1000-3428.2011.06.058The traditional Open Vehicle Routing Problem(OVRP) assumes that the demand of the clients can not be split and the type of vehicles is the same, but in the practical logistics distribution, the type of vehicles is not exactly the same, sometimes the transportation cost can be reduced by splitting the demand of clients to make the best of the loading capacity of vehicles. This paper proposes the Split Delivery Open Vehicle Routing Problem with Heterogeneous Vehicles(SDOVRPHV), presents mathematic model of the integer programming of the problem, solves it with Tabu search algorithm and improves the generation of the initial solution and neighborhood structure in the algorithm. By experiments, the validity of the model is validated, and the results are compared with the traditional OVRP which indicates that the algorithm can reduce effectively the transportation cost.
-
Computer Engineering. 2011, 37(6): 172-174. https://doi.org/10.3969/j.issn.1000-3428.2011.06.059To partition complex networks into groups fast and correctly, this paper proposes an algorithm for detecting community structures in complex networks based on shared neighbors and local modularity. By looking for the numbers of shared neighbors between nodes one by one, the node connected closely with the community is found, and the local modularity is used to decide whether this found node is added into the community. Three typical complex networks are used to test the performance of the algorithm. Experimental results show that it is viable and effective.
-
Computer Engineering. 2011, 37(6): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2011.06.060A new technology of real-time detection on infrared dim moving point targets in image sequences is studied. Through speed and direction of small target, useless trajectories is cut, which reduces calculation amount and calculation time greatly. The technology based on multistage hypothesis test which detects the dim moving point targets and delete the trajectories of noises is used. It gets the targets more accurate. Experimental results show that the technology requires less calculation and has good real-time performance.
-
Computer Engineering. 2011, 37(6): 178-180. https://doi.org/10.3969/j.issn.1000-3428.2011.06.061
An Improved Harmony Search(NIHS) algorithm is presented for Lot-streaming Flow shop Scheduling Problem(LFSP) with objectives of makespan. Ranked-Order-Value(ROV) is applied to enable the continuous harmony search algorithm to be applied to scheduling problem. The initial harmony memory and the method of generating candidate solution is improved. Aiming at the shortcoming of premature and poor resulted from pure NIHS, two hybrid algorithms are put forward by combining NIHS and Threshold Accepting(TA). Simulation results show the effectiveness of the algorithm.
-
Computer Engineering. 2011, 37(6): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2011.06.062Aiming at the face sequence, the face feature points are tracked by using modified Kanade-Lucas-Tomasi(KLT) after extracting face feature points accurately. According to characteristics of face shape, it uses a number of face feature points as the face model. After estimating the face pose approximately, 3D space face pose is estimated accurately via modified Broyden-Fletcher-Goldfarb-Shanno(BFGS). Experimental result shows that the method can gain only 3D face pose, and has better estimation accuracy compared with similar methods.
-
Computer Engineering. 2011, 37(6): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2011.06.063In this paper, a new method of getting inertia weight, Subsection Weight(SW) is proposed in order to solve the Particle Swarm Optimization(PSO) disadvantages which are likely to fall into local optimum and slow converge. The diversity of swarm increases at the prophase and the convergence is accelerated in the later period. Meanwhile, the combination of SW and GB can improve the evolutionary equation of PSO and makes it perform better. Experimental result shows that the algorithm can effectively avoid converging too early and increase the precision in solving multiple sequence alignment.
-
Computer Engineering. 2011, 37(6): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2011.06.064On the basis of describing the Open Vehicle Routing Problem with Time Windows(OVRPTW), a Multi-Start Tabu Search(MS-TS) algorithm is presented. In this algorithm, the random initial solution is generated by the two-phase method of combining the sweep algorithm and push forward insertion heuristic, the neighborhood structure is constructed by a mixed heuristic algorithm, the capability of global optimization is improved by designing global and local Tabu list. With the normal test examples, the experiment is done, and a good optimization result is obtained.
-
Computer Engineering. 2011, 37(6): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2011.06.065Aiming at the phenomena such as the dependence on parameter control, precocity and stagnation of Ant Colony Algorithm(ACA), and the character that ACA is easily combined with other algorithms, the Differential Evolution(DE) algorithm is put into making decision of choosing the ACA’s parameters. A new adaptive ACA is proposed, named DEAS. This algorithm regards the parameters of ACA as the elements of DE algorithm’s solution vector and adaptively finds the optimal combination of parameters, and the optimal solution for solving the problem. The new algorithm effectively overcomes the influence of control parameters of ACA and decreases the numbers of useless experiments. It is adaptive, good at global-search and prevents the degradation of populations. The comparison with the basic ACA indicates DEAS improves the performance significantly. With some appropriate attempts the algorithm can also be used to solve other combinatorial optimization problems.
-
Computer Engineering. 2011, 37(6): 193-194. https://doi.org/10.3969/j.issn.1000-3428.2011.06.066
An algorithm for plagiarism-detection of scientific papers based on local word-frequency fingerprint is presented. Sentence is regarded as the basic component elements of a document, and extracting efficient keywords, sorting and reconstructing them. According to the code and word-frequency, the fingerprints are get to compute text similarity degree. The identification experiments on SOGOU-T database are done with the algorithm. Experimental results show that it partly overcomes the shortage of existing plagiarism-detection of scientific papers, and it has better performance on identification precision and identification speed.
-
Computer Engineering. 2011, 37(6): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2011.06.067Considering the contradiction between efficiency of convergency and search capability, a novel approach, search space division and movement strategy, which will separate the search mechanism from evolution mechanism, is proposed. The corresponding theory is put forward based on a deep study of both traditional and improved evolutionary algorithms. The extremums will compete with each other in different circumstances, for using the region movement mechanism which is based on the theory space division strategy. And the search capability of system is improved a lot. The improved region processor without any concern of the search problem in each region is efficient. The record is designed not only to enable the region processor to exchange information effectively, but also control the region movement mechanism in terms of various requests as well. Experimental results show that this strategy has remarkable advantage in accuracy and efficiency.
-
Computer Engineering. 2011, 37(6): 198-199. https://doi.org/10.3969/j.issn.1000-3428.2011.06.068
Aiming at the multi-objective problem in actual traffic, a multi-objective optimization method based on hierarchical GA-AS algorithm is proposed. The hierarchical structure is adopted by constraints. The Ant Colony Algorithm(ACA) is used in a few of subnets for the local optimization, and the Genetic Algorithm(GA) is used in the top for the global optimization. Simulation results show that this algorithm not only has a strong effect of practical applications, but also reduces the number of optimization calculations, and its performance is improved.
-
Computer Engineering. 2011, 37(6): 200-202. https://doi.org/10.3969/j.issn.1000-3428.2011.06.069This paper proposes using wavelet modulus maxima de-noising method. Image containing noise is took discrete stationary wavelet transform, the noise standard deviation is estimated, changes in the form of Bayes-shrink threshold, and gets de-noising threshold formula. The paper judges the wavelet coefficients modulus maxima generated by the edge image in each scale wavelet coefficients of each sub-band, uses the adaptive multi-threshold to atrophy wavelet coefficients for non-image edge in each wavelet sub-band of all different scales. The stationary wavelet inverse transform of the image is performed after de-noising. Experimental results show that the proposed de-noising method has better effect.
-
Computer Engineering. 2011, 37(6): 203-205. https://doi.org/10.3969/j.issn.1000-3428.2011.06.070A segmentation filling algorithm based on queue for super resolution image is proposed. This algorithm is composed with two steps: segmentation and filling. It is suitable for filling super resolution images, including geological maps of basin modeling. It overcomes low efficiency, low accuracy and waste of computer resources in the process of super resolution images. According to the characteristics of basin modeling, the application of this algorithm achieves better results than other algorithms.
-
Computer Engineering. 2011, 37(6): 206-208. https://doi.org/10.3969/j.issn.1000-3428.2011.06.071This paper introduces the procedure and features for image compression using Set Partitioning In Hierarchical Trees(SPIHT) coding based on DWT, summarizes the aspects of improved SPIHT algorithm, analyzes the advantages and disadvantages of the algorithm profoundly, gives some initial treatments which do not affect the algorithm main frame in accordance with the above disadvantages and develops the algorithm, which can reduce the redundancy and improve the encoding speed. Theoretical analysis and experimental result show the proposed algorithm can enhance the PSNR with low bit rate and maintain high PSNR with high bit rate.
-
Computer Engineering. 2011, 37(6): 209-211. https://doi.org/10.3969/j.issn.1000-3428.2011.06.072In the standard multi-scale Retinex algorithm, a constant gain is applied to a Retinex output, which leads to overenhancement in smooth and edge regions, in which noise amplification and ringing artifacts take place, respectively. An improved Multi-Scale Retinex(MSR) algorithm is proposed by applying the adaptive space varying gain, which means larger gain is applied to pixels in smooth and edge regions while smaller gain is applied to pixels in detail regions. Meanwhile, the gain difference is larger between pixels of Retinex output associated with a small Gaussian surround space constants while the gain difference is small between pixels of Retinex output associated with a large Gaussian surround space constants. When the proposed algorithm is applied to images severely degraded by fog, experiments show that the algorithm can effectively remove fog degradation from color images.
-
Computer Engineering. 2011, 37(6): 212-214. https://doi.org/10.3969/j.issn.1000-3428.2011.06.073In order to reduce conflict between whole layer and local detail during color image quantization, this paper proposes an octree color quantization method of visual saliency. It introduces the visual attention mechanism into color image quantization. After analysing the method and theory of getting visual saliency image in visual saliency model, the paper gets the disadvantage that traditional octree color quantization has scarcity of quantizing detail, consults salient image during color register to increase the frequency of color in visual saliency area. Compared with result of octree color quantization, image quantized has more layers in color expression, less distortion in detail and has clear contours.
-
Computer Engineering. 2011, 37(6): 215-217. https://doi.org/10.3969/j.issn.1000-3428.2011.06.074
This paper introduces a nonlinear transformation multiple description image coding algorithm based on the Region Of Interest(ROI). It can be compatible with the current standard image compression algorithms, and give the ROI better protection. The redundance can be got from the nonlinear geometric transformation of the ROI, and sampling of the images to form the Multiple Description Coding(MDC). Through the simulation experiment, when the images are in the error-prone channels and lose descriptions, the algorithm can be a better method to recovery the ROI.
-
Computer Engineering. 2011, 37(6): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2011.06.075This paper combines the characteristics of Blending Interpolation Spline(BIS), proposes a new method for image interpolation. The method can meet the demands of the images zoomed by arbitrary positive real number times. Using a single kernel function and without presenting additional computation in image interpolation in order to satisfy the interpolating conditions, it provides the less computational complexity. The edge-preserving characters can be realized by the flexible border. Experimental results show the method has more clear border compared with the normal cubic polynomial methods.
-
Computer Engineering. 2011, 37(6): 221-222. https://doi.org/10.3969/j.issn.1000-3428.2011.06.076
According to texture of the halftone image. a new wavelet packet halftone image compression is proposed, in which the scan mode of the wavelet packet coefficients and the selection of threshold function are improved. The encoding method of high frequency and low frequency is different. Experimental results show that the new method can get better effect.
-
Computer Engineering. 2011, 37(6): 223-224. https://doi.org/10.3969/j.issn.1000-3428.2011.06.077
Lossless compression rate obtained on the error-diffusion image is very low, and the conventional binary image lossy coding techniques can provide bad visual quality on these images, which lead to investigate lossy compression based on the inverse halftone method. A looking up table inverse halftone method is used to convert error-diffusion image back to the contone image. An improved DCT coding algorithm is constructed to get higher compression rate. A lossy compression method of error-diffusion image is proposed. Experimental results show that the proposed algorithm fits to the error-diffusion image, and the quality of the decoding image is well.
-
Computer Engineering. 2011, 37(6): 225-227. https://doi.org/10.3969/j.issn.1000-3428.2011.06.078The transmission, processing and display of spatial data put a higher demand for Web Geographic Information System(WebGIS). This paper focuses on secondary development based on digital earth model, implements Web Mapping Service(WMS) using GeoServer as WebGIS server, builds a pyramid model of data caching mechanism, analyzes the system architecture, and designs the WebGIS based on digital earth. The applications of hydraulics comprehensive integration and flood inundation based on WebGIS demonstrate that it has greater practicability and scalability.
-
Computer Engineering. 2011, 37(6): 228-230. https://doi.org/10.3969/j.issn.1000-3428.2011.06.079According to the spreading features of mechanical vibration fault, five kinds of Petri net models of fault diagnosis and the corresponding algorithm are proposed. The software engineering is approached to analyze, design and implement the system of mechanical vibration fault diagnosis. Practice proves that this method reduces the failure diagnosis rate and missed diagnosis rate. The difficult problem of fault diagnosis and prediction for mechanical vibration under complex environment is solved.
-
Computer Engineering. 2011, 37(6): 231-233. https://doi.org/10.3969/j.issn.1000-3428.2011.06.080
The safety computer of railway transportation is the key equipment in charge of safety of railway transportation. Its safety level must be the Safety Integrty Level 4(SIL4). This paper compares characteristics of 2 out of 3 structure and double 2-vote-2 structure, designs 2 out of 3 safety computer based on ReWorks embedded operating system, and studies its middleware. It is applied in railway transportation project, and gets good practical effect.
-
Computer Engineering. 2011, 37(6): 234-236. https://doi.org/10.3969/j.issn.1000-3428.2011.06.081In order to solve the problem of large-scale bridge fault diagnosis, this paper proposes a new efficient algorithm. It addresses the issue of identifying abnormal cliques on bridges, where each clique is composed of a deflection checkpoint and the dedicated sensor. The detection method consists of three stages. First, inspired by “deflection resonance” between different checkpoints, a test pattern is created based on the theory of regression. Second, a set of tests on cliques are conducted based on the established test pattern, and the test outcomes are collected to form a syndrome. Finally, a detection result is achieved based on the syndrome. The proposed method is then applied to the detection of a real-life bridge, and result shows the detection rate reaches 81.8%.
-
Computer Engineering. 2011, 37(6): 237-238. https://doi.org/10.3969/j.issn.1000-3428.2011.06.082
An IEEE 1588 server, which is based on the foreground/background system with the priorities of interrupts, is designed and implemented to meet the high precision requirement of time synchronization in distributed power systems by using an ARM?Cortex?-M3 based microcontroller, which supports IEEE 1588 protocol. The burden of microcontroller is reduced and the real-time performance is further improved as a result of adopting the lightweight TCP/IP stack and simplifying the protocol’s complexity to program the bottom communication software. It is shown in test experiments that this server characterizes high clock-synchronization accuracy, excellent stability and low cost, and it has a bright prosperity to be applied into practice.
-
Computer Engineering. 2011, 37(6): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2011.06.083This paper focuses on the online scheduling problem of real-time task based on two-dimension dynamic reconfiguration system, presents a placement strategy based on maximal adjacent edges, and proposes a Secondary Preemptable Scheduling Algorithm(SPSA) for hardware tasks, i.e., deprive the reconfigurable resource of the reserved task, then performing unified off-line scheduling. Experiment shows the proposed algorithm has a higher task acceptance rate and a more effective chip utilization, without markedly runtime overhead increased.
-
Computer Engineering. 2011, 37(6): 242-244. https://doi.org/10.3969/j.issn.1000-3428.2011.06.084Traditional barcode and RFID can only carry the merchandise ID or little basic information with fixed capacity, which can not provide a low cost scheme that carrying large capacity information. This paper proposes an application of a self-developed 2D continuous matrix high density barcode in modern logistics industry. The barcode has low cost, fault tolerant capability and could carry large capacity information with changeable and adjustable capacity. It provides a high reliability, low cost solution for carrying large capacity product information in modern logistics industry.
-
Computer Engineering. 2011, 37(6): 245-246. https://doi.org/10.3969/j.issn.1000-3428.2011.06.085This paper presents a 3D multi-core parallel loading system using for rendering scene. Loading the scene with OGRE, multi-thread creation and synchronization using OpenMP and setting the number of threads dynamically is adopted in parallel programs in the multi-core computers. The instances of rendering through the mountains on a 3D scene loading different number of plants are constructed. The time of loading Mesh under different threads is tested from those instances to obtain an excellent speedup. Experimental results show that the OpenMP parallel technology can effectively improve loading rate of 3D scene rendering and speed up the display of the terrain scene, and it improves the efficiency of the rendering system.
-
Computer Engineering. 2011, 37(6): 247-249. https://doi.org/10.3969/j.issn.1000-3428.2011.06.086
On the meet the current meteorological characteristics of national industry demands lightning detection data visualization technology, the final implementation of lightning data fusion of two-dimensional and three-dimensional interactive displays. It uses object-oriented languages Visual Studio .Net(C#) integration ArcEngine for lightning detection data development of three-dimensional display system to solve lightning data in two-dimensional and three-dimensional map of the handling and display problems. The article describes the ArcEngine component of the second development, map data processing as well as two-and three-dimensional lightning data interaction between display methods. Experimental results show the practice of using the above method of construction of the national lightning detection data three-dimensional display system to better meet the real business needs, as lightning protection and provide more intuitive decision support service information.
-
Computer Engineering. 2011, 37(6): 250-252. https://doi.org/10.3969/j.issn.1000-3428.2011.06.087Aiming at the problem that there is little local cooperative information used in cooperative co-evolution mechanism, by improving the cooperative co-evolution for Multi-Satellite TT&C Scheduling(MSTS), this paper emphasizes the local interaction function under global cooperation, proposes a performance index for individual——Local Interaction Value(LIV), which indicates its cooperative effectiveness with its neighbor populations, and takes LIV as one of the measures of individual quality in the selection operation. In order to improve the mutation self-adaptation, the difference between LIV and sum of all child fitness is taken to determine the mutation probability, which can reduce the phenomenon of losing excellent individuals due to the non-global characteristic of delegate individuals. Simulation result shows that it can improve the quality of solution.
-
Computer Engineering. 2011, 37(6): 253-255. https://doi.org/10.3969/j.issn.1000-3428.2011.06.088The specific application requirements from modern gas industry are analyzed. Information system for gas management based on ArcGIS, called GasGIS, has been developed. Such main functionalities are carried out as the conjunctive query by site type, selected regional, road location and gas pipeline schedule-time, unified map service, three-dimensional spatial analysis, emergency dispatching decision and the conversion and import & export of the map data. Visualization effect of the statistical information further meets the needs of users of the system.
-
Computer Engineering. 2011, 37(6): 256-259. https://doi.org/10.3969/j.issn.1000-3428.2011.06.089The rapid development of P2P based Internet Protocol Television(IPTV) has brought many potential security risks. The accurate detection of IPTV platform is the prerequisite for its effective supervision. In this paper, based on the flow features and behavior features of network traffic, by using support vector machine method, selecting PPlive, PPstream, QQlive, Sopcast and UUsee as representatives for IPTV platforms, it designs and implements an IPTV platform real-time detection system. Experiment results show the system can detect whether the managed node is using an IPTV platform, and it is with 90.62% correct rate within 5 minutes.
-
Computer Engineering. 2011, 37(6): 260-262. https://doi.org/10.3969/j.issn.1000-3428.2011.06.090In order to describe the self-similarity of the online forums article number sequences, the FARIMA process based on fractional differential and the ARMA process is employed to study and analyze the sequences. FARIMA model has the characteristics of high accuracy and time complexity. In order to reduce the time complexity of FARIMA model, ?-ARMA model is proposed. Simulation experiments compare the computational complexity and fitting accuracy, and the results prove the validity of the ?-ARMA model.
-
Computer Engineering. 2011, 37(6): 263-265. https://doi.org/10.3969/j.issn.1000-3428.2011.06.091To solve the problem of tags collision in RFID system, a new anti-collision algorithm based on classical binary-search algorithms is proposed to improve identification efficiency. In order to reduce query frequency and data interchange in the collision processing, the new algorithm adopts the techniques of stack and queue storage, back strategy, collision-bit tracking and parallel processing, etc. The algorithm can make reader only send a three-dimensional-vector order, and tags respond to the reader with some of collision-bit parameters. The algorithm utilizes the queue to store identified ID, and makes both read-write operations and collision processes work simultaneously, thus read-write time is left out. The reader has dual-core processor by using parallel processing modules. Performance result shows that this algorithm is significantly superior to the classical binary algorithms in reducing data interchange and query frequency.
-
Computer Engineering. 2011, 37(6): 266-268. https://doi.org/10.3969/j.issn.1000-3428.2011.06.092
A proposal on the wireless mobile video surveillance based on DirectShow is presented. The mobile nodes capture video information using the camera, transmit it through WI-FI or GPRS network to the surveillance centers, thus the surveillance centers can monitor the mobile nodes in real time, also all nodes can do video communication among them. The proposal is different from the conventional, it is valid as the video surveillance screen is fluent in better real time measurement verified by the experiment. Experimental analysis is given and the directions for further research are put forward.
-
Computer Engineering. 2011, 37(6): 269-271. https://doi.org/10.3969/j.issn.1000-3428.2011.06.093The test of integrated circuit physical design needs random generating rectilinear polygon to cover all the cases. A novel algorithm that generates a random simple rectilinear polygon is presented. This polygon can be used for testing and analyzing algorithms in VLSI physical design. The algorithm generates an ordered sequence of points, and then untangles each pair of intersecting line segments until no more can be found. The finiteness of the algorithm is proved. Experimental results show that this algorithm is simple and efficient.
-
Computer Engineering. 2011, 37(6): 272-273. https://doi.org/10.3969/j.issn.1000-3428.2011.06.094Traditional L-shaped tile simulation method is usually used to researching unidirectional double-loop networks, and can not be used in the bidirectional double-loop networks directly. In order to solve the problem, this paper presents a fast simulation algorithm based on cartesian coordinates, which is used in the research of the bidirectional double-loop networks. By using the algorithm, the graph of the bidirectional double-loop networks G(N;±r,±s) for any given N, s can be simulated, and the diameter, the average distance, including each node are signed on the graph. Simulation result indicates that the characteristic of distribution of diameter and the average distance is clear.
-
Computer Engineering. 2011, 37(6): 274-276. https://doi.org/10.3969/j.issn.1000-3428.2011.06.095This paper introduces the principle of VIRE algorithm for indoor location. For the positioning accuracy of boundary tags in VIRE positioning algorithm is low, BVIRE algorithm is proposed by using boundary virtual reference tags. BVIRE algorithm inserts some virtual reference tags on the boundary of the indoor environment by establishing a linear regression equation. Simulation results show that, BVIRE algorithm improves the positioning accuracy of boundary tags significantly without adding extra reference tags and radio frequency interference compared with VIRE algorithm.
-
Computer Engineering. 2011, 37(6): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2011.06.096In order to meet the requirements of real-time video copy detection, a method of rapid video fingerprint scheme is presented. The video fingerprint is generated by combining both the improved ordinal measure feature and the improved motion feature based on the DC image sequences. The query video streams can be identified by matching the candidate video. Experimental results show that the proposed video fingerprint has the advantage of higher discrimination and lower time complexity.
-
Computer Engineering. 2011, 37(6): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2011.06.097This paper proposes an I/O acceleration strategy for network computing system established by iSCSI protocol——iSCSI transparent reliable multicast based on similar payload. By detecting the similar payload form I/O request blocks and extending iSCSI protocol, it constructs double data transport paths: one is for iSCSI PDU, and the other is for similar payload. Consequently the transporting of network compute data is accelerated. Experimental result shows that the strategy can improve the I/O performance of concurrent clients.
-
Computer Engineering. 2011, 37(6): 283-285. https://doi.org/10.3969/j.issn.1000-3428.2011.06.098This paper proposes a prediction model based on linear programming to predict the home broadband customers, and uses exponential smoothing and ARIMA models to predict broadband market space based on the model. Experimental results show that the model has better accuracy on predicting home broadband customers as well as broadband market space prediction, which provides supports for broadband business development and strategic decision of carriers.
-
Computer Engineering. 2011, 37(6): 286-289. https://doi.org/10.3969/j.issn.1000-3428.2011.06.099Aiming at the characteristics of node operating system and its demands for real-time performance, security and concurrency, this paper proposes a new kernel schedule algorithm for real-time system. By combining task priority dispatching with time slot cycling, it boosts the response speed of the processor, and improves the real-time characteristics of the system. The strategy is implemented on ?COS-II, and the modified kernel is applied to the wireless acquisition system, whose result proves that the algorithm reduces response time of the system and improves its efficiency.
-
Computer Engineering. 2011, 37(6): 289-290. https://doi.org/10.3969/j.issn.1000-3428.2011.06.100For head-mounted eye gaze tracking, additional head position sensors is needed to determine the gaze direction, a new method based on marker detection is proposed to estimate the gaze of point for head-mounted system in this paper. The markers are detected by computer vision method, and the relationship between scene image and computer screen is constructed with point correspondences in two views. The point of gaze in the scene image is translated to computer screen coordinate. Experimental result shows that this method can estimate the point of gaze in real scene easily irrespective of user’s head position.
-
Computer Engineering. 2011, 37(6): 291-292. https://doi.org/10.3969/j.issn.1000-3428.2011.06.101This paper proposes an improved two-stage T2-BIC algorithm for speaker segmentation, because traditional T2-BIC algorithm has the problems of a bigger accumulated error and a lower recall ratio. In the first stage, the peak position of T2 statistic in search window is detected by using improved sliding variable-size analysis window, and Bayesian Information Criterion(BIC) algorithm is used to acknowledge the peaks. In the second stage, the idea of divide-and-conquer is used to detect the missed turns because of low BIC reliability. Experimental result shows that compared with other algorithms, the improved algorithm achieves better performance, and improves the precision, recall and F measure.
-
Computer Engineering. 2011, 37(6): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2011.06.001Aiming at the problem that stereoscopic vision measurement exists the lack of visual field and feature point is difficult to match, this paper analyzes the non-linear model of camera distortion effects, and uses Simulated Annealing Particle Swarm Optimization(SAPSO) algorithm to get the solution of camera calibration model’s over determined equation. It uses laser ranging to achieve the realization of monocular vision measurement. Experimental results demonstrate the better calibration results and measurement precision of this algorithm.
-
Computer Engineering. 2011, 37(6): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2011.06.002This paper presents a feature extraction method of foreign fibers in lint cotton by analyzing chrominance distributions of cotton image. Cg is substituted for Cb and then the YCrCg color space is formed to extract the foreign fiber features. To fuse the chrominance features effectively, the moment-preserving principle is employed to realize the dimensionality reduction. The final results of foreign fiber features are obtained by the threshold segmentation of the fusion image. Experimental result shows that it is useful to enhance the contrast between cotton and foreign fibers and smooth the background interference, which helps to improve the extraction accuracy of foreign fiber features.
-
Computer Engineering. 2011, 37(6): 7-8. https://doi.org/10.3969/j.issn.1000-3428.2011.06.003This paper proposes an expert search algorithm based on query proximity. It builds query word proximity of probability language model according to query word concordance in window, and uses classical probability model as background smooth. The distance dependencies between multiple query terms and it then ranks the candidates and combines with the distance between candidates and query terms. Experimental results show that employing query proximity in expert search improves the precision score significantly and a combination of both kinds of dependencies can achieve better performance.
-
Computer Engineering. 2011, 37(6): 9-11. https://doi.org/10.3969/j.issn.1000-3428.2011.06.004
This paper researches the impact of antenna correlation at User Equipment(UE) on performance limits of multi-user Distributed Multiple-Input Multiple-Output(D-MIMO) systems. Contrary to the traditional view that correlation is detrimental in a single-user D-MIMO system, simulation results show that antenna correlation at UE actually can provide a noticeable performance gain which mainly comes from two aspects, which are multi-user diversity and power focusing effect in a multi-user environment.
-
Computer Engineering. 2011, 37(6): 12-14. https://doi.org/10.3969/j.issn.1000-3428.2011.06.005
The main jamming against digital nulling antenna on satellites is hostile high-power blocking interference. Aiming at the situation, this paper proposes nulling state maintain and interfering resource information store strategy. Nulling state maintain strategy can prevent the nulling antenna from the potential threat of blinking-jamming, avoid the impact of nulling antenna passive frequent nulling for system stability. The interfering resource information store strategy can get nulling state maintain time with pertinence, avoid the situation of blindly setting nulling state maintain time which can not adapt to all kinds of interfering strategy, and it makes nulling antenna has stronger adaptability.
-
Computer Engineering. 2011, 37(6): 15-17. https://doi.org/10.3969/j.issn.1000-3428.2011.06.006Behavior evolution is main method for Continuous Petri Net(CPN) model. However, it can not offer all analysis for CPN. To analyze Interval Continuous Petri Net(ICPN) by timed automata, the state evolution graph for ICPN is developed, and the timed automata for ICPN is proposed based on a state evolution graph. Through case study, the effectiveness and necessity of the proposed method are illustrated.
-
Computer Engineering. 2011, 37(6): 18-20. https://doi.org/10.3969/j.issn.1000-3428.2011.06.007Aiming at the Hammerstein model with unknown memory depth, this paper proposes a blind identification method of memory effect for Hammerstein model based on high cumulant. The memory depth determination is converted into finding the rank of extended matrix constructed by cumulants of system output. In order to yield the rank of cumulant matrix. It proposes Nonlinear Product Of Diagonal Entry(NPODE) method, and simulation verifies its robustness by comparing with GM method and inflexion method. Linear block coefficients extraction method is given, the theoretical derivation and simulation result indicates that the extraction process is not affected by the strength of nonlinearity of Hammerstein model.
-
Computer Engineering. 2011, 37(6): 21-23. https://doi.org/10.3969/j.issn.1000-3428.2011.06.008This paper researches the technology of automatic summarization, and presents a method that extracts summarization in multiple topics document, which combines statistics with text relationship map, and uses the algorithm of community partition in complex networks. This method extracts some sentences that have higher weight and builds text relationship map according to similarity computation of sentences, and then uses the algorithm of community partition in complex networks to solve the problem of sub-topic partition. Experimental results show that this method is more efficient for summarization extraction in multiple topics document and can extract more sub-topics.
-
Computer Engineering. 2011, 37(6): 24-26. https://doi.org/10.3969/j.issn.1000-3428.2011.06.009Traditional water wave simulation can not generate realistic water surface. Aiming at this problem, this paper proposes an improved method for water simulation. It uses Gerstner wave model to produce water surface geometry, decomposes the water surface into a set of intersected parts with modified surface entropy, disturbs the vertex normal with different degree, by modifying texture mapping for water surface to improve reality, and applies the optics based on GPU. Experimental result demonstrates that the method can generate realistic water model and get higher rendering efficiency.
-
Computer Engineering. 2011, 37(6): 27-29. https://doi.org/10.3969/j.issn.1000-3428.2011.06.010To improve efficiency and robustness of fixed time signal control, the paper establishes an adjustable multi-objective optimization model to optimize signal timing. The objective function consists of two sub-targets, of which the first sub-target including three indicators such as average delay, number of stops, traffic capacity is to optimize efficiency, and the second sub-target is to optimize stability of signal control by minimizing standard deviation of vehicle delay. Based on simulation and analysis of intersections under various traffic conditions, the study establishes the relationship between sub-target weights and flow fluctuating ranges. This paper uses genetic algorithm to solve it. Results show that the multi-objective optimization model reduces the average delay of vehicles and controls maximum delay effectively.
-
Computer Engineering. 2011, 37(6): 30-31. https://doi.org/10.3969/j.issn.1000-3428.2011.06.011This paper considers both the contextual clues and context-independent statistical clues, using syntactic analysis and method of point of mutual information, building related dictionaries to extract the evaluation object in products comments. Experimental results show that this method is better than Baseline method which gets the latest word as the evaluation object in precision rate and F-measure.
-
Computer Engineering. 2011, 37(6): 32-34. https://doi.org/10.3969/j.issn.1000-3428.2011.06.012By analyzing the advantages and disadvantages of the existing file systems, aiming at the limited resources and poor stability characteristics of embedded file systems, this paper puts forward a new large-capacity file storage structure named MSFS(M Structure File System). It introduces the file system architecture and internal composition, tests reading and writing performance and makes comparison with the traditional and common file systems based on embedded system. Experimental results show the advantages of MSFS in storage and stability.
2024
Volume 50 No 3
Volume 50 No 3
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428