15 February 2013, Volume 39 Issue 2
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Computer Engineering. 2013, 39(2): 1-5. https://doi.org/10.3969/j.issn.1000-3428.2013.02.001
According to the adaptive bitstream matching technology of terminal services pull mode, this paper proposes a real-time adaptive bitstream switching algorithm for HTTP streaming. It uses the sliding window to analyze the time for downloading each video segmen. Hypothesis testing is used to judge whether there is a rate jump, which degrades the estimation significantly, in present observing window. The Ek/D/1/N queue is employed to model the number of segments in the receiver buffer and to figure out the underflow probability. Customized values of loss and benefit are set to underflow risk and stream quality respectively. A stream with optimal integrated benefit is considered to be the target stream. Experimental results show that the proposed algorithm can determine the appropriate downloading stream based on the current available bandwidth, with good performance of rate adaption.
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Computer Engineering. 2013, 39(2): 6-11. https://doi.org/10.3969/j.issn.1000-3428.2013.02.002
In the process of mobile communication, the service efficiency is low if the communication situation cannot be known in advance. Aiming at this question, this paper proposes a method for communication situation estimating based on the Hidden Markov Model(HMM). In general, user behaviors change as the time goes. It utilizing this feature gives a time slots division method and concrete algorithm according to the difference of efficiency, genetic algorithm or traversal algorithm. Then by mining the relationship between time, location and service, it builds HMM. This paper utilizes Viterbi algorithm to predict the communication situation. Simulation results show that the location predicting success rate is 73% and the behavior predicting success rate is 75% when the pattern feature value is 0.8.
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Computer Engineering. 2013, 39(2): 12-17. https://doi.org/10.3969/j.issn.1000-3428.2013.02.003
In order to help people find researchers, knowledge and fields of study more accurately and efficiently, this paper designs and develops a recommendation system based on the academic relationship of researchers like co-authors relationship. It models the researcher using the keywords in the papers that the researcher has authored, and uses the academic relationship of co-authors in papers to calculate the similarity to other researchers and recommend researchers. Experimental result verifies that compared with the method without considering the academic relationship, the precision can be increased by 5% or more.
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Computer Engineering. 2013, 39(2): 18-22. https://doi.org/10.3969/j.issn.1000-3428.2013.02.004
Considering the unique characteristics of low data transfer rate and high energy consumption in Underwater Acoustic Sensor Network(UWASN), this paper presents a routing protocol based on correlation-aware in UWASN. It merges data according to their correlation during the process of routing for reducing communication and network energy consumption. Moreover, this protocol can also balance energy consumption of varies nodes in case some nodes exhaust their energy. Simulation results show that the protocol achieves relatively high packet transmit rate with low energy consumption.
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Computer Engineering. 2013, 39(2): 23-26. https://doi.org/10.3969/j.issn.1000-3428.2013.02.005
Based on the thorough analysis and study on the structural characteristics of Context-based Adaptive Variable Length Coding(CAVLC) code tables, this paper proposes a new table lookup algorithm for CAVLC decoding with the statistical law of code tables. The idea of this algorithm is based on the relationship between the numbers of zero in code prefix and the length of code. With it, it proposes a scheme, in which the code suffix and the code value are determined by the relationship between the numbers of zero in code prefix and the length of code, and it can decode the input code quickly. As a result, a specific input code can be decoded with only one time table lookup. Test results show that the optimized algorithm can achieve 20% speed-up in the table lookup compared with the original algorithm.
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Computer Engineering. 2013, 39(2): 27-33. https://doi.org/10.3969/j.issn.1000-3428.2013.02.006Aiming at the lack of a comprehensive analysis and metrics for energy consumption in the cloud computing, and from a view of ecosystem, the concept of green computing ecosystem based on the hierarchical structure is presented, and its analysis model is designed. In addition, the energy consumption factors in the structure of green computing ecosystem are analyzed in this paper. With the design of ACTTest experimental test program, the Web components of the system, cluster technology and the energy consumption of call spending are mainly tested. Experimental results show that this system can improve the efficiency in saving energy and it enables the green computing.
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Computer Engineering. 2013, 39(2): 34-40. https://doi.org/10.3969/j.issn.1000-3428.2013.02.007In order to solve the problem of privacy-preserving in outsourcing association rule mining, this paper proposes an algorithm which is based on independent mapping space Bloom filters to overcome the low time efficiency and poor reversibility. The algorithm translates the original transaction of database into the form of Bloom filter. It compresses the affairs according to the Hamming weight of each transaction vector transformed. It calculates the support of candidate itemsets through “and” every column vector of matrix. It obtains the frequent itemsets. The experimental results show that, compared with the original algorithm, the algorithm improves the time efficiency while ensures the low misdiagnosis rate, furthermore, it has good reversibility, high safety and stronger practicality.
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Computer Engineering. 2013, 39(2): 41-45. https://doi.org/10.3969/j.issn.1000-3428.2013.02.008This paper proposes a Web application monitoring system based on business process, through analyzing and summarizing the status and development trend of network application monitoring and process control systems. The system uses process recording technology to realize custom monitoring business process and Web data mining to identify and obtain business processes. It separates the data collection and monitoring services to reduce the impact of monitoring object. The actual results of monitoring proves that the Web application monitoring system based on business processes not only can complete the work of traditional monitoring system, but also can provide the information of business processes, which are excavated from these monitoring data. It provides accurate and effective basis for software systems, optimization, quality improvement and system reconfiguration.
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Computer Engineering. 2013, 39(2): 46-49. https://doi.org/10.3969/j.issn.1000-3428.2013.02.009The current rules extraction methods mostly only extract rules in consistent decision system, and the extracted rules redundant degree is high, it is not easy to understand for users. Aiming at this problem, this paper puts forward a rule extraction method based on cover object set. It divides object set into corresponding equivalence class by using rough set theory, produces effectiveness rules according to the consistency of the similarity degree, and solves inconsistent decision system rules extraction through the equivalence partitioning and object set cover. Numerical example analysis result proves the validity and reliability of the method, and it has good robustness.
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Computer Engineering. 2013, 39(2): 50-54. https://doi.org/10.3969/j.issn.1000-3428.2013.02.010This paper proposes Continuous Probabilistic Skyline Query in Subspaces(CPSQS) over sliding window on uncertain data streams. Moreover, a novel algorithm using a regular grid index, which is adaptable for solving subspace skyline issue, is presented to reduce the dominating testing costs. At the same time, based on the subtle relationship between the probabilistic bounds of full space and an arbitrary subspace, a set of pruning strategies are developed to improve the performance of CPSQS. Analytical analysis and experimental results show that this algorithm can meet individuation query of users, reduce query response time.
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Computer Engineering. 2013, 39(2): 55-60. https://doi.org/10.3969/j.issn.1000-3428.2013.02.011Web service security tools nowadays provide security configuration functionality at single Web services level, neglecting security requirement from business process layer. A Web service security framework towards multi-party collaboration application is proposed in this paper, which incorporates the enterprise business process management with security processes including security modeling, deployment and monitoring. Corresponding modeling tools, converting tools and monitoring tools based on Secure-WSCDL are constructed, synchronizing business model and security model throughout the entire software engineering lifecycle in SOA architecture. It verifies the effectiveness of the model and the tools by the simplified international trade import and export process instance.
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Computer Engineering. 2013, 39(2): 61-66. https://doi.org/10.3969/j.issn.1000-3428.2013.02.012In order to improve the traditional way of ultra-short wave wireless network construction, this paper studies how to form the optimal network by adding mobile nodes to a group of necessary nodes. In order to achieve the balance of network construction cost, reliability and communication quality, it designs a hierarchical optimization model. To solve this model, it proposes a hierarchical multi-objective optimization approximation algorithm. According to the priority levels of objective functions, the algorithm can achieve the approximate optimal solution which meets constraints. Simulation results show that this algorithm can effectively achieve the approximate or even the same solution as the optimal solution. Compared with the GLiD algorithm, this algorithm can plan a better network with less construction cost, higher reliability and better communication quality.
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Computer Engineering. 2013, 39(2): 67-72. https://doi.org/10.3969/j.issn.1000-3428.2013.02.013The paper utilizes the Dynamic Source Routing(DSR) protocol in Mobile Ad-hoc Networks(MANET) to design a node protocol based on diversity in energy consumption. It introduces the energy threshold and the diversity energy consumption into the calculation of the path cost in the route discovery phase, and it selects the appropriate transmission path according to topological structure and energy consumption of each node in the path. So that the data packets can through different paths on balance, to extend the survival time of the entire network. Simulation results show that, compared with the classic DSR protocol and REECV protocol, the proposed protocol has a certain improvement in the performance indicators of the death of nodes, network lifetime and delivery rate.
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Computer Engineering. 2013, 39(2): 73-76. https://doi.org/10.3969/j.issn.1000-3428.2013.02.014Due to Gauss model has larger ranging error because of environmental path dispersion index, Reference-G mode is proposed. This mode uses Gauss distribution function to filter small probability Received Signal Strength Indicator(RSSI) values, and uses the known distance and measured RSSI between anchor nodes to correct the distance by being measured RSSI value, thus path dispersion index is eliminated. Simulation result shows that the ranging of Reference-G is independent on environment, and location errors in different environment are almost equal. The number of anchor nodes in Reference-G is less than 1/3 of Gauss mode with same errors.
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Computer Engineering. 2013, 39(2): 77-80. https://doi.org/10.3969/j.issn.1000-3428.2013.02.015Aiming at the problem of the traffic flow performance by node failure, a novel status prediction algorithm Trous-based ARIMA Prediction(TAP) of Ad hoc network is proposed. In this algorithm, wavelet transform is adopted to ease up the long dependence of actual traffic, and the status prediction formula is built by Autoregressive Integrated Moving Average(ARIMA) model and Kalman filter. A simulation is conducted to study the accuracy between TAP and ARIMA, as well as FARIMA. Results show that TAP has better performance, and the residual is 18.23%.
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Computer Engineering. 2013, 39(2): 81-84. https://doi.org/10.3969/j.issn.1000-3428.2013.02.016The complexity of sphere detection algorithm is high when the Signal to Noise Ratio(SNR) is low. For this problem, a new type of detection algorithm of sphere decoder is proposed. The new algorithm reduces the radius of sphere when the SNR is low by using the Minimum Mean Square Error(MMSE) algorithm and a compressibility factor. With the result of simulation, it shows that when the SNR is less than 10 dB, the proposed algorithm reduces the average complexity by 10% compared with original sphere decoding algorithm and does not cause obvious loss of performance.
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Computer Engineering. 2013, 39(2): 85-89. https://doi.org/10.3969/j.issn.1000-3428.2013.02.017Dynamic spectrum allocation is a key technology of the Cognitive Radio(CR). Subject to bit error rates, total transmit powers and interference thresholds that primary users can tolerate, a greedy allocation algorithm for multi-objective optimization of Orthogonal Frequency Division Multiplexing(OFDM)-based CR systems is proposed in this paper. The proposed algorithm minimizes the transmit power and the mutual interference, and meets the Quality of Service(QoS) requirements of Secondary User(SU). The multi-objective optimization problem is converted to a single-objective one through linearly combining the three objective functions, and the greedy algorithm is used to solve the optimization problem. Simulation results show that the total system capacity of the proposed algorithm is close to its maximum, and the mutual interference is reduced as well as the QoS requirements of SU are effectively met.
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Computer Engineering. 2013, 39(2): 90-93. https://doi.org/10.3969/j.issn.1000-3428.2013.02.018The delivery manner of data blocks among nodes causes the streaming play quality of data-driven P2P streaming system. Aiming at the problem of data block delivery scheduling, a scheduling strategy is proposed, which takes it into account the impact of a desired block of a node to the streaming play quality of that node. The strategy guarantees the streaming play quality, while utilizes the bandwidth resource of nodes efficiently. Simulation experimental results show that the strategy has evident advantage in improving streaming media play quality.
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Computer Engineering. 2013, 39(2): 94-98. https://doi.org/10.3969/j.issn.1000-3428.2013.02.019Aiming at the problem of the confusion of the signal flow direction and the processing delay. Based on the cross-layer design, a graded cross-layer QoS framework with link-independent layer and the interface between the link-independent layer and the link-dependent layer as well as the link-dependent layer is presented. And the QoS management framework and module of the graded layer and the interface between the link-dependent and the independent layer are designed. Where, the link-dependent layer is cross-layer designed by the physics layer and the link layer to adapt to the variance of the channel. The link-independent layer is cross-layer designed by the up IP layers which maps the service’s QoS to the wireless resource in the interface, which makes the flow direction of the signal simpler and the processing delay shorter and realizes the end-to-end adaptation. Simulation results show that the optimal mapping and the graded cross-layer design improve the throughput of the system.
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Computer Engineering. 2013, 39(2): 99-102.For computing the Minimum Connected Dominating Set(MCDS) in the network, a new algorithm is proposed based on Glowworm Swarm Optimization(GSO) algorithm. Each node of network is considered as individual glowworm emitting luciferin whose intensity is dependent on the degree of the node. By use of the scheme of probabilistic selection and luciferin adjustment, some nodes are attracted toward its neighbors having higher intensity of luciferin, and in this way, a dominated set of the network is constructed which contains the priority individuals. The nodes of the dominating set are connected and a pruning rule is applied to eliminate some redundant nodes for MCDS. Numerical results in Unit Disk Graphs(UDG) modeling wireless networks show the GSO-based algorithm can provide smaller CDS scale, and it is closer to centralized algorithm.
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Computer Engineering. 2013, 39(2): 103-107. https://doi.org/10.3969/j.issn.1000-3428.2013.02.021In the applications, the identity of nodes in mobile Ad hoc network may be different. According to the situation, this paper proposes an asymmetric key management framework for the mobile Ad hoc network. In order to satisfy the special framework, it designs a new secret sharing scheme for splitting the system private key, in which it generates two kinds of shares of the system private key: the special share and the ordinary share, so that it needs two kinds of shares to recover the system private key. Furthermore, it presents a limited verifier signature scheme in mobile Ad hoc network based on this secret sharing. Analysis results show that the scheme has a good availability since all nodes share the master private key and the decreases computation complexity, which is one time modular exponentiation and Euclid algorithm in signature phase, O(t) times modular exponentiation in verification phase. Besides, it is as safe as partially distributed key management sign scheme.
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Computer Engineering. 2013, 39(2): 108-111. https://doi.org/10.3969/j.issn.1000-3428.2013.02.022Iterated rational secret sharing scheme only fits for the case of infinite rounds. But the secret sharing scheme with infinite rounds is not efficient. Combined with finitely repeated game theory, this paper proposes a new (m+1,n) finite iterated rational secret sharing scheme assigning each player a time limit based on Shamir’s secret sharing scheme. Analysis results show that a rational secret sharing scheme within constant rounds can be constructed when the time limit and payoff functions suffice some conditions, where each player can reconstruct the secret.
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Computer Engineering. 2013, 39(2): 112-118. https://doi.org/10.3969/j.issn.1000-3428.2013.02.023In open environment, the user nodes and resource nodes are variable, and it is almost impossible to check their priorities to access different kind of resources in the system in which the traditional Role Based Access Control(RBAC) model is adapted. To simplify the access control and standardize security strategy in open system, a flexible RBAC model based on trust degree is proposed. It uses the evaluation between the user node and resource node to calculate they direct trust, and employs the evaluation among the resource nodes to get the recommended trust of the resource nodes. Using the two trust values, together with the session history of user nodes and resource nodes, the system assigns the roles as well as its corresponding priorities for the user node flexibly. It adopts the Additive-increase, Multiplicative-decrease(AIMD) algorithm, which is widely used in TCP congestion control algorithm, in the trust evaluation to punish the node with malicious behaviors.
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Computer Engineering. 2013, 39(2): 119-124. https://doi.org/10.3969/j.issn.1000-3428.2013.02.024By analyzing the principle, mode, characteristics of Denial of Service(DoS) attack aiming at Session Initiation Protocol(SIP) and flooding attack faced by SIP network, this paper proposes a prevention model combining a dynamic threshold adjustment with real-time dynamic prevention for SIP flooding attack. It can dynamically adjust the threshold and detect SIP flooding attack through chi-square traffic judging mode and cumulative statistics mode, and can dynamically prevent IP-based SIP flooding attacks with IP defense model. Experimental result shows that the model can effectively detect and prevent the SIP flooding attack, and reduce the probability of SIP/IMS server being attacked when SIP network is on the abnormity.
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Computer Engineering. 2013, 39(2): 125-129. https://doi.org/10.3969/j.issn.1000-3428.2013.02.025Beginning with the research of the basic concepts of Universally Composable(UC) framework, the requirement of UC security on commitment protocols is analyzed in this paper, and the reason of the problem that all UC commitment protocols do not exist in the plain model is pointed out that the security requirement of commitment protocol and the requirement of UC security are contradictory. On the basis of this, a UC secure commitment protocol UCCOM using tamper-proof hardware is proposed. Analysis result shows that UCCOM does not depend on any trusted third-party and uses fewer cryptographic operations compared with the related works, so it has higer efficiency.
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Computer Engineering. 2013, 39(2): 130-136. https://doi.org/10.3969/j.issn.1000-3428.2013.02.026In order to simplify the certificate management process of the traditional public key system and solve the problem about private key escrow in the identity-based public key system, this paper proposes a new certificateless blind signature scheme which combines certificateless signature and blind signature. Analysis result shows that the new scheme is blind, untraceability and unforgeability in random oracle model and under the q-strong Diffie-Hellman complexity assumption and the inversed Diffie-Hellman complexity assumption. The signing algorithm does not require any pairing computation and the verification algorithm only needs a pairing computation, so that the scheme proposed is more efficient.
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Computer Engineering. 2013, 39(2): 137-140. https://doi.org/10.3969/j.issn.1000-3428.2013.02.027Information hiding algorithm based on pitch prediction for low bit-rate speech coding is presented. In the pitch prediction coding process, the searching range of adaptive codebook in the closed-loop pitch search is used to realize the secret information embedding. Information hiding and speech coding are synchronously implemented. The algorithm not only has better steganography performance, but also has lower computational complexity. In G.729a, the statistical average embedding bit-rate of secret information is up to 374.636 bit/s, the deterioration of Perceptual Evaluation of Speech Quality(PESQ) is less than 10.4% and testing accuracy is less than 66%.
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Computer Engineering. 2013, 39(2): 141-144. https://doi.org/10.3969/j.issn.1000-3428.2013.02.028In order to detect illegal copies of videos, this paper proposes a video fingerprinting algorithm based on kurtosis image. The video clip is preprocessed and key frames are selected by using a random variable with uniform distribution. The kurtosis images of key frames are computed and Discrete Cosine Transform(DCT) is applied into the kurtosis images. The video fingerprints are generated with the lager DCT coefficients. During video fingerprints matching, a sliding window method is used for matching, and the identification of videos is achieved. Experimental results prove that bit error rates are below 10% under common attacks.
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Computer Engineering. 2013, 39(2): 145-149. https://doi.org/10.3969/j.issn.1000-3428.2013.02.029Based on the theory of quadratic residues, this paper considers the algebraic structure of in the two order strong RSA algorithm. It is proved that the element of gets maximal order if and only if , and the numbers of quadratic residues in the group is . is divided up by the group which is composed of all quadratic residues, and all cosets form a Klein eight-group. It proves that the group can be generated by seven elements of quadratic non-residues.
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Computer Engineering. 2013, 39(2): 150-154. https://doi.org/10.3969/j.issn.1000-3428.2013.02.030Previous grouping proof protocols for Radio Frequency Identification(RFID) tags suffer from the replay attack to the reader and have low reliability. In order to sovle the problem, an improved high-reliable RFID grouping tag proof protocol is proposed. The legality of the tag and the reader identity must be mutual verified, each tag communicates independent with the reader, and there is no information transmission between tags, so that the new protocol has high security and blocks replay attack. Formal analysis result based on BAN logic demonstrates the correctness and security of the protocol.
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Computer Engineering. 2013, 39(2): 155-159. https://doi.org/10.3969/j.issn.1000-3428.2013.02.031This paper presents an object based self-embedding watermarking that can restore the moving objects completely at the receiver end. In order to guarantee consistent received objects, a new method of extracting the moving objects is adopted that using an artificial frame but not the original one. Experimental results show that the moving objects can be restored completely when the stego-video is un-tampered or the tampered area is not too extensive.
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Computer Engineering. 2013, 39(2): 160-163. https://doi.org/10.3969/j.issn.1000-3428.2013.02.032Wang Guozhan et al.(Computer Engineering, 2010, No.3 and No.8) attacks a proxy blind signature scheme proposed by Gu Lize et al. and a multi-proxy blind signature scheme proposed by Lu et al. respectively, and points out that the two schemes do not satisfy the property of blindness. Aiming at Wang et al.’s attack to the scheme of Gu Lize et al and the scheme of Lu et al., this paper points out that Wang Guozhan et al.’s attack is not valid, and uses the method of construction to prove that the proxy signer can not use gained information to track signature. Analysis result shows that both of Gu Lize et al.’s scheme and Lu et al.’s scheme still satisfy the property of blindness and they are unlinkable.
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Computer Engineering. 2013, 39(2): 164-167. https://doi.org/10.3969/j.issn.1000-3428.2013.02.033It is difficult to implement RSA algorithm, which depends on the operations of the large numbers and needs better computation resource with higher computing speed and much more memory. Aiming at the problem, this paper proposes an effective solution dividing the large integer into multiplication of small integers to improve the speed of power multiplication. Besides, it designs a well load balanced parallel algorithm, and improves the speed of computing time further. Experimental results show that the algorithm is better than traditional algorithm in computing time and it has a good scalability.
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Computer Engineering. 2013, 39(2): 168-171. https://doi.org/10.3969/j.issn.1000-3428.2013.02.034The presence of invalid sound segments leads to quickly reduce the recognition performance of the sound recognition method in the noise condition. This paper presents an anti-noise sound recognition method based on the energy detection. Energy detection method is used to detect the existence of the sound signal under the noise conditions. In addition, it extracts Mel-frequency Cepstral Coefficient(MFCC) features from the frames which are detected the presence of the sound signal by the energy detection. A Support Vector Machine(SVM) classifier uses the extracted feature vectors to train the classification model and recognizes the ecological environmental sound. Experimental results show that this method has good anti-noise ability, and the recognition rates are more than 25% higher than the system before adding the energy detection when the Signal to Noise Ratio(SNR) is less than 40 dB.
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Computer Engineering. 2013, 39(2): 172-177. https://doi.org/10.3969/j.issn.1000-3428.2013.02.035It is frequent to produce a large number of noise in the outdoor complex traffic environment by traditional object detection method. Traditional three-dimensional Otsu method can eliminate the effect of image noise, but can not satisfy the real-time demand. To solve the above problems, a method for three-dimensional Otsu moving vehicle detection based on decomposition is proposed. Two difference images are got by the method of interval frame symmetry differencing. Two binary images are obtained after using a method based on decomposition three-dimensional Otsu. Moving cars are got by seeking the common ground in these two binary images after filtering with mathematical morphology. Experimental results show that it can detect moving cars for real-time and accuracy in the case of jittering in the video frame.
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Computer Engineering. 2013, 39(2): 178-181. https://doi.org/10.3969/j.issn.1000-3428.2013.02.036In order to find local outliers in data stream, this paper analyzes traditional outliers detection algorithms, and intro- duces an outlier detection algorithm based on Wavelet Density Estimation(WDE). It uses a multi-scale and multi-granularity characteristics of WDE using the wavelet probability threshold to judge the data stream within the current sliding window data points as outliers, and discusses outlier detection in data stream process. Simulation results show that this algorithm has higher detection efficiency and accuracy in the data stream than Kernel Density Estimation(KDE) algorithm.
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Computer Engineering. 2013, 39(2): 182-186. https://doi.org/10.3969/j.issn.1000-3428.2013.02.037In order to reduce the circular array pattern of the peak sidelobe level, this paper proposes a circular array pattern optimization method based on modified Genetic Algorithm(GA). This method makes the location of the array element and the coefficient as joint variables. By minimizing beam pattern peak sidelobe as the objective function, it not only can enhance the variables freedom degree but also can use GA to optimize the array element position and array element weights. In order to avoid premature convergence, differential evolution, interpolate, one-point crossover, multi-point crossover can be united based on the double choice mechanism. Experimental results show that this method can reduce the probability of getting into the local advantages, have good fitness and faster convergence speed, and make the peak sidelobe level decrease to ?12.611 dB.
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Computer Engineering. 2013, 39(2): 187-191. https://doi.org/10.3969/j.issn.1000-3428.2013.02.038Aiming at the bad performance of terrain classification based on one sensor, a terrain classification method based on visible light and infrared images is proposed. Extracting features from visible and infrared images, nearest neighbor classifier and minimum distance classifier are adopted to estimate the posterior probabilities. The probabilities from different features and classifiers are weighted composed. The features’ weights are computed by scatter while the classifiers’ weights are obtained by experiments. In the estimate of posterior probabilities based on minimum distance classifier, Mahalanobis distance is used instead of Euclidean distance. Experimental results show that the recognition accuracy of cement road and gravel road are 99.33% and 96.67%, which are higher than similar algorithms.
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Computer Engineering. 2013, 39(2): 192-196. https://doi.org/10.3969/j.issn.1000-3428.2013.02.039Two models of visual attention, bottom-up and top-down, which are consistent with human visual perception are introduced to traffic sign detection region. In this paper, it puts forward a way of traffic sign detection based on the visual saliency map. The features of color, shape, intensity and orientation are obtained to make saliency map. It finds the Region of Interest(ROI) by using of the Winners Take All(WTA) network. Experimental results show this method can accurately position the traffic sign in the cases of complex background images.
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Computer Engineering. 2013, 39(2): 197-201. https://doi.org/10.3969/j.issn.1000-3428.2013.02.040Considering the kernel function bandwidth of traditional Mean Shift tracking algorithm cannot be adaptively adjusted and is liable to be effected in similar color, a multi-feature adaptive scale Mean Shift tracking algorithm is proposed. The algorithm combines color and texture information to create feature model, which creates the target probability density distribution in optimal target location, and calculates the wide and high of density blob, thus, the target scale is adaptively adjusted. Target the object with ellipse, parameters is obtained by calculating moment of probability density. Experimental results show that the algorithm can effectively meet the goal of scaling, rotation and other complex motion, and not sensitive to lighting change and similar color.
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Computer Engineering. 2013, 39(2): 202-206. https://doi.org/10.3969/j.issn.1000-3428.2013.02.041For the problem of multi-attribute decision making, in which the attribute values are the Interval Intuition Trapezoidal Fuzzy Number(IITFN) and the weights are intervals, an IITFN multi-attribute decision model is presented based on the maximizing deviation. It calculates the distance between attribute and ideal solution, then the deviation between attribute and ideal solution of each scheme are defined. The optimization model of multi-attribute decision making is constructed based on the maximum deviation, by using Lingo means the weights of attribute is given. By using the weighted arithmetic average operator of the IITFN, the total deviation of each scheme is provided, and then scheme is ranked based on the total deviation. Example results show that this model needs few operation steps, and is easy to realize.
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Computer Engineering. 2013, 39(2): 207-210. https://doi.org/10.3969/j.issn.1000-3428.2013.02.042To solve this problem about the accuracy of the present Chinese keyword extraction algorithm, this paper presents a new keyword extraction algorithm based on competitive learning network. The algorithm adopts the method that it takes the divided word which comes from the Chinese article as the single neuron. And it can get one or more active neurons after these neurons are input the input layer and compete with each other on the competition layer. The keywords of the Chinese article are obtained through merging the weights and clustering analysis. Experimental results show that the hit rate of extracting keywords with this algorithm is higher than the algorithm of Term Frequency-inverse Document Frequency(TF-IDE) and the traditional algorithm named Term Frequency(TF), and has a good robustness.
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Computer Engineering. 2013, 39(2): 211-215. https://doi.org/10.3969/j.issn.1000-3428.2013.02.043For the Capacitated Arc-routing Problem with Stochastic Demand(CARPSD), an adaptive local search algorithm is proposed. It generates the initial population which is based on Stochastic Path Scanning(SPS), and selects the best one as the initial solution. Adaptive local search is implemented to speed up the convergence rate. For the selection of search operation, two local search mechanism are designed. Experimental results show that the optimum solution of this algorithm is improved, the running time is shorten by 60% compared with the Adaptive Large Neighborhood Search(ALNS) algorithm.
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Computer Engineering. 2013, 39(2): 216-219. https://doi.org/10.3969/j.issn.1000-3428.2013.02.044In order to detect the surface defects, this paper proposes an automatic detection algorithm based on Principal Component Analysis(PCA). The process uses PCA to make the image reconstruction to enhance the defects, and makes comparison with the original image and reconstruction image to get the defect information. The defects are detected after the statistical process control binarization. Experimental results show that the detection effect of this algorithm is good, operation speed is fast, for 80 different surface images, average defects detection rate is 80%.
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Computer Engineering. 2013, 39(2): 220-224. https://doi.org/10.3969/j.issn.1000-3428.2013.02.045Traditional Chinese sentence computing algorithm has a lower accuracy in dealing with a large number of professional vocabulary. In order to solve this problem, this paper proposes a Chinese sentence similarity algorithm based on dynamic programming. By getting the common sub-string collection of two sentences, it combines the mechanism for duplicate elimination by linked list, and obtains all of the longest common sub-string of two sentences for computing similarity. Experimental results show that for the problem sets which contain a lot of proper nouns, the test accuracy of this algorithm is 93.6%, and has high computational efficiency.
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Computer Engineering. 2013, 39(2): 225-228. https://doi.org/10.3969/j.issn.1000-3428.2013.02.046Existing interactive segmentation algorithms are sensitive to quantity as well as placement of user’s scribbles, hence a novel algorithm which employs region cue is proposed. Segmentation result by mean-shift algorithm is regarded as imaginary pixels, and further incorporated into construction of two-layer weighted graph, which provides long range connection between homogenous semantic areas. Then all these connections are integrated in a chrominance iteration formulation, which performs updating to membership of all pixels to every label. Segmentation is completed via comparison to resulting membership. Experimental results indicate that even little amount of scribble can result in satisfactory result, which demonstrates that the proposed method has higher robustness to quantity and placement of scribbles in comparison with existing mono-layer ones.
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Computer Engineering. 2013, 39(2): 229-232. https://doi.org/10.3969/j.issn.1000-3428.2013.02.047The traditional projection matrix algorithm is more complicated, and its efficiency is low. For this reason, a new algorithm based on two-dimensional index is proposed. Similar to the position of the each element in a matrix, the element can be located by a row and column. Each row and column can be calculated simply and simultaneously, so the algorithm is more efficient. Experimental result by GATE simulation software shows that the new algorithm is six times faster than classical Siddon algorithm, and the image can be reconstructed well.
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Computer Engineering. 2013, 39(2): 233-236. https://doi.org/10.3969/j.issn.1000-3428.2013.02.048By considering advantages and complementary of spatial and frequency textures features, an adaptive texture image retrieval method is presented combined with Local Binary Pattern(LBP) feature and Brushlet domain coefficient statistical feature. Frequency feature is described as energy feature of every Brushlet subband. Spatial feature is LBP histogram. Similarity between images is measured by improved Canberra distance. Further, closed-loop feedback is introduced to adjust weights adaptively for image retrieval. Experimental results show that average recall rate of this method based on fused features is 8.93% and 18.66% higher than LBP method and Brushlet domain method respectively.
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Computer Engineering. 2013, 39(2): 237-240. https://doi.org/10.3969/j.issn.1000-3428.2013.02.049This paper researches the technonlogy of point cloud data reconstruction in laser scanning, and proposes a fast method of curved surface reconstruction based on point cloud. It analyses the relative position of the relationship of data points between adjacent scanning lines, and improves scanning lines subdivision algorithm based on triangular subdivision, according to the characteristics of the progressive scanning laser scanning. The point cloud data is irregular triangular mesh divided. It uses geometrical relationship to make triangular network construction. At the same time, on the basis of the triangle model, the triangular mesh is optimized locally, to make texture mapping, and to be rebuild in the end. Experimental results show that this algorithm can effectively improve the speed and quality of triangular network construction, eliminate voids and improve the reconstruction results.
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Computer Engineering. 2013, 39(2): 241-244. https://doi.org/10.3969/j.issn.1000-3428.2013.02.050A seamless image stitching method based on Affine-SIFT(ASIFT) algoithm is proposed in this paper. It implements automatically and makes up the disadvantages of traditional image registration methods under greatly different scale, parallax and illumination conditions. It adopts ASIFT algorithm for the detection of feature points, which is robust to the case of strong affine. Then it does the extraction and matching of feature points. With Random Sample Consensus(RANSAC) algorithm, it finds the accurate initial transform matrix through iteration, and accomplishes the unity of coordinate transformation between two images. The seamless image stitching is completed with smoothing algorithm. Experimental results demonstrate that this method has better performance than the method based on SIFT.
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Computer Engineering. 2013, 39(2): 245-249. https://doi.org/10.3969/j.issn.1000-3428.2013.02.051Aiming at the problem that photovoltaic Maximum Power Point Tracking(MPPT) controls speed unsteadily, an improved variable step size Incremental Conductance(INC) method MPPT algorithm is proposed. By improving INC method step change trigger conditions, the proposed algorithm can improve the MPPT response speed and accuracy at steady state simultaneously when the irradiance occurs a substantial change. Simulation results show that the proposed algorithm has a faster response speed and higher tracking accuracy in sudden large irradiance changes.
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Computer Engineering. 2013, 39(2): 250-253. https://doi.org/10.3969/j.issn.1000-3428.2013.02.052Considering the fact that special interconnects begin to exist in new Field Programmable Gate Array(FPGA) architectures. This paper proposes an algorithm based on improved depth-first search. Each programmable interconnecting point is equally treated. After a graph representation of interconnects is got, a weight parameter for each edge is set and the edge with the minimum weight is picked to be part of a test net, thereby testing open faults and short faults of interconnects. Experimental results show that the proposed algorithm can be utilized to cover special interconnects of FPGA architectures and exhibits high automation.
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Computer Engineering. 2013, 39(2): 254-259. https://doi.org/10.3969/j.issn.1000-3428.2013.02.053This paper presents a statistical method to build up interconnect timing library of Static Timing Analysis(STA) to improve the accuracy of the simulation result of Field Programmable Gate Array(FPGA) STA module. The timing library based on the method of cumulative frequency method can get a better result compared with linear simulation input library. Simulation error can be reduced to 8.23%, which is far smaller than the traditional linear simulation input library.
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Computer Engineering. 2013, 39(2): 260-264. https://doi.org/10.3969/j.issn.1000-3428.2013.02.054Aiming at solving problems such as how to generate various Pulse Width Modulation(PWM) signals, a PWM signal generator based on Field Programmable Gate Array(FPGA) is proposed in this paper. It uses Verilog to customize system peripherals, and a NiosII soft-core processor is embedded in the FPGA chip, which enables to generate multi-channel PWM signal through collaborative work of hardware and software. Experimental results show that the output range of its frequency is 1 Hz~ 4 MHz, adjustable range of duty cycle is 1%~99%, and phase range between two signals is 1°~180°, achieving the desired effect.
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Computer Engineering. 2013, 39(2): 265-269. https://doi.org/10.3969/j.issn.1000-3428.2013.02.055The environment of the Yellow River Delta is becoming more and more bad. In order to assess the vulnerability of the Yellow River Delta, this paper designs the vulnerability assessment system. It builds the assessment index system of the Yellow River Delta, establishes the vulnerability assessment index quantification system based on the expert integration method, and processes the collected data, and adopts analytic hierarchy process to determine the weights of assessment indexes. The assessment system of the Yellow River Delta is implemented with the language of C# and ArcEngine component. This system runs under the environment of VS2005. Analysis results show that this system is favor of management of the data, and benefits to query and analysis of the information for the administrator quickly and accurately.
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Computer Engineering. 2013, 39(2): 270-273. https://doi.org/10.3969/j.issn.1000-3428.2013.02.056The problem of large-scale project scheduling with risk consideration is studied. Rule of risk is proposed and a measurement method is considered in the plan-making. This paper establishes a time-cost-quality-risk integrated optimization model. A local optimization algorithm is proposed based on critical path method and slack time, which is used to improve the Multi-objective Evolutionary Algorithm based on Decomposition(MOEA/D). Case study result shows that the model and the algorithm are suited to solve engineering optimization problem.
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Computer Engineering. 2013, 39(2): 274-278. https://doi.org/10.3969/j.issn.1000-3428.2013.02.057A strategy based on automated search for probability distribution construction is proposed, which comprises the design of representation format and evaluation function for the probability distribution. Combining with simulated annealing algorithm, an indicator is defined to formalize the automated search process based on the Markov model. Experimental results show that the method effectively improves the accuracy of the automated search, which can reduce the expense of statistical test by providing the statistical test with fairly efficient test data since it successfully finds the neat-optimal probability distribution within a certain time.
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Computer Engineering. 2013, 39(2): 279-282. https://doi.org/10.3969/j.issn.1000-3428.2013.02.058For the problem of the operating system thread schedule in multi-core environment, this paper puts forward a thread schedule strategy based on thread pipeline. In order to take full parallel advantage of the pipeline, based on the Chip Multi-thread(CMT) processor, it introduces the concept of thread-pipeline. Through the determination of the thread feature indexes, it calculates the thread pipeline aggregations degrees, and corresponding thread coincidence degrees, thus completes the thread schedule. On this basis, it adjusts some optimization for embedded application. Through the comparative experiment simulated real environment, it verifies that thread pipeline schedule strategy can consume less time than schedule strategy based on static-priority.
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Computer Engineering. 2013, 39(2): 283-287. https://doi.org/10.3969/j.issn.1000-3428.2013.02.059To solve the problem that a scheduling procedure in equipment support is complex and lower efficiency, a new equipment support task scheduling method is proposed. In terms of the task’s executive processes, Equipment Support Atomic Task(ESAT) and correlation matrix of ESATs are defined, and a triple is constructed to formalize the equipment supporting issue. Making the Equipment Support Task Scheduling Problem(ESTSP) equivalent to a multi-stage decision-making problem, the task is decomposed into some subsequences of ESATs based on the property of priority, and each subsequence’s correlation matrix and weighted undirected graph are constructed and it is better rearranged using a modified Ant Colony Optimization(ACO) algorithm, An optimal sequence of the task is given by linking the subsequences. Experimental rusults show that the algorithm is practical.
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Computer Engineering. 2013, 39(2): 288-292. https://doi.org/10.3969/j.issn.1000-3428.2013.02.060Dezert-Smarandache Theory(DSmT) is an effective information fusion method for highly conflicting evidence problem of Dempster-Shafer Theory(DST). Combination rules play an important role in DSmT fusion. The fused result depends on the performance of combination rules. Different combination rules are suitable for dissimilarity evidence in distinct condition. The properties of combination rules are analyzed in three aspects as combination property, time series property and engineering property. Simulation results show that the properties presented characterize the combination rules roundly. It offers a theoretic foundation for analysis, improvement and application of DSmT combination rules.
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Computer Engineering. 2013, 39(2): 293-298. https://doi.org/10.3969/j.issn.1000-3428.2013.02.061By analyzing the unique characteristics of reduction cyclic algorithm for solving tri-diagonal linear system, this paper presents an optimized algorithm specially for Godson 3B processor. The reduction cyclic algorithm is implemented on Godson 3B platform based on its vector instructions and vectorization techniques are used to boost performance of the algorithm. Experimental results show that, comparied with non-vectorization algorithm, vectorization algorithm larger enhances the performance.
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Computer Engineering. 2013, 39(2): 299-303. https://doi.org/10.3969/j.issn.1000-3428.2013.02.062Under the situation of peace and disaster time, this paper studies a deploying problem of suppliers with the uncertain demand. A stochastic mixed integer programming model is built to deal with the location problem of suppliers in peace time. It is important to note uncertain demands are studied by expected-value and stochastic simulation approach. And then based on the model for peace time, an integer programming model is built for disaster time. Simulation results show that the model can effectively coordinate the suppliers deploying problem, and it can provide a guideline to the future research of integral deploying problem in peace and disaster time.
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Computer Engineering. 2013, 39(2): 304-310. https://doi.org/10.3969/j.issn.1000-3428.2013.02.063There is one serious drawback in video copy detection, which is that the high detection speed and the high detection precision can not be achieved simultaneously. To overcome this problem, this paper proposes a video copy detection method based on shot duration and texture information. It uses long lens as characteristics to establish inverted index structure, puts them into database, makes the query video segmentation, and matches them with the database to get the first copy detection results, then uses texture information of key frames to verify the detection result. Experimental results show that this method has good detection speed, and the precision rate and recall rate are 1.
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Computer Engineering. 2013, 39(2): 311-316. https://doi.org/10.3969/j.issn.1000-3428.2013.02.064According to the technical factors and non-technical factors which influence the Quality of Experience(QoE), this paper proposes a QoE assessment model, and presents the users’ subjective feelings and network factors through the model. It proposes a new Key Quality Indicator(KQI) indexes’ weight calculation method on the basis of the model. In this algorithm, it uses Fuzzy Analytic Hierarchy Process(FAHP) to calculate the initial KQIs’ weight, changes the KQIs’ weight via the non-technical factors, and makes the static QoE evaluation process be dynamic and real-time. Simulation results demonstrate this method can guarantee that the technical factors and non-technical factors which influence the degree of QoE are side by side with 50%, and can reflect the users most intuitive and true feelings.
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Computer Engineering. 2013, 39(2): 317-320. https://doi.org/10.3969/j.issn.1000-3428.2013.02.065For the processes in the resource-constrained project scheduling problem must be executed in a special time window, an Improved Electromagnetism-like Mechanism Algorithm(IEMA) which is based on Variable Neighborhood Search(VNS) is proposed. A VNS strategy is used as its local search policy and charge calculation, total force and particle moves style are improved. IEMA is applied to solve the standard problem libraries PSPLIB. A comparison between IEMA, EM, IEM and IEM-NS is presented and experimental results show that IEMA has better performance.
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