05 September 2012, Volume 38 Issue 17
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Computer Engineering. 2012, 38(17): 1-4. https://doi.org/10.3969/j.issn.1000-3428.2012.17.001For the supervision of special goods, the solution is introduced for the environment context aware system based on Internet of Things(IoT) technology. It specifically focuses on the design process of the context awareness gateway. The hardware of the gateway is based on ARM11 processor, which can perceive on the multi-source, process and transmit environmental context information. The software of the gateway uses Linux operating system. The design can obtain high-precision sensing data by using digital filtering techniques, nonlinear compensation technology and parameter mapping technology. The application verifies that the system not only can monitor the distributed multi-source environment context, but also can realize intelligent service through data mining deeply.
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Computer Engineering. 2012, 38(17): 5-8. https://doi.org/10.3969/j.issn.1000-3428.2012.17.002To be aimed at the safety of personnel on the strange tide of natural disaster, a personnel position system based on middleware of Internet of Things(IOT) is designed in this paper. The system includes the control unit of satellite and base to collect personnel information, obtain coordinate information by Global Position System(GPS) and all kinds of sensor identification unit of Radio Frequency Identification(RFID). Transmission of the date from read radio frequency identification on the tide beach to the computer. They are analyzed by the center server. As a consequence of the above, the managers can understand the operations staff position quickly through the monitoring data and take timely relief measures.
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Computer Engineering. 2012, 38(17): 9-11,15. https://doi.org/10.3969/j.issn.1000-3428.2012.17.003For keeping salt safe, this paper presents a tracking and traceability system. It achieves the system with Radio Frequency Identification(RFID) technology, and RFID is used to collect data for tracking and tracing function. The system can automatically collect, store data, and display in a good way. Experimental results show that this system can manage salt efficiently, conveniently and stably and keep salt product safety.
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Computer Engineering. 2012, 38(17): 12-15. https://doi.org/10.3969/j.issn.1000-3428.2012.17.004There are large amount of different sensing networks linked together in Internet of Things(IoT). To meet the heterogeneous data access requirement for sensing layer of IoT, this paper gives a solution named Chukwa’s eXtension(ChukwaX), which adopts the hierarchical architecture to disperse the whole access pressure and adaptor pattern to match different protocol. ChukwaX also supports sensing network dynamic accessing which makes sensing networks keeping both local autonomy and Ad-Hoc access. Experimental result on prototype system building based on Chukwa shows that ChukwaX can meet the heterogeneous sensing network access requirement and it is with the high scalability.
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Computer Engineering. 2012, 38(17): 16-19. https://doi.org/10.3969/j.issn.1000-3428.2012.17.005According to the booming increase of network transmitted data or information and the corresponding network bandwidth insufficiency caused by the popularization of Internet of Things(IoT) key supporting technologies, such as cloud computing and data mining, this paper proposes an IoT remote machine control scheme based on a novel dynamic bandwidth resource allocation algorithm, which optimizes the bandwidth usage by scheduling the sampling rates of the control signals. Simulation results show under the same network bandwidth condition, this algorithm can reduce the reconstruction signal’s error as well as enhance the intelligent bandwidth allocation capability in IoT system.
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Computer Engineering. 2012, 38(17): 20-23. https://doi.org/10.3969/j.issn.1000-3428.2012.17.006A remote farmland monitoring system based on Internet of Things(IOT) technology is designed to solve the high-price of the Internet access and high flow load of the remote data-center. The system adopts Wireless Sensor Network(WSN) to collect the environmental information and the embedded gateway based on ARM11, which accesses to the Internet using the 3G technology. Meanwhile a mobile client is developed for user to view the information and control the devices. Analysis results show that the system can effectively monitor and control the farmland information, and be suitable for the needs of modern agricultural development.
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Computer Engineering. 2012, 38(17): 24-27. https://doi.org/10.3969/j.issn.1000-3428.2012.17.007To simplify the implementation of embedded virtual memory and improve the performance of embedded virtual memory, this paper proposes an improved Least Recently Used(LRU) page replacement algorithm. It is based on Memory Manage Unit(MMU), across page access count, access sequence register, overflow interruption techniques of software and hardware. Experimental result shows that it has higher page replacement efficiency and overall system performance, and can be widely used into the Internet of Things(IoT) system and embedded system.
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Computer Engineering. 2012, 38(17): 28-31. https://doi.org/10.3969/j.issn.1000-3428.2012.17.008Existing Web service discovery methods don’t consider the behavior of the process related information, therefore the found service can not meet the demand of user and has lower precision. Aiming at the problem, this paper proposes a Web Services process discovery method based on Web Ontology Language for Service(OWL-S) process model. It transforms OWL-S process model into process graph, then calculates the degree of matching of two service process models according to the similarity of two process graphs. Experimental result shows that this method can accurately match two service process model, and it has the high efficiency and good matching effect.
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Computer Engineering. 2012, 38(17): 32-34. https://doi.org/10.3969/j.issn.1000-3428.2012.17.009According to the definition of strong vertex-distinguishing total coloring, this paper combines with the symmetry of complete graph, proposes a new strong vertex-distinguishing total coloring algorithm. The algorithm divides the filled colors into two parts: overcolor and propercolor. At the premise of getting the coloring number and the coloring frequency, it uses colored at first to enhance its convergence. Experimental results show that this algorithm has a lower time complexity.
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Computer Engineering. 2012, 38(17): 35-37,41. https://doi.org/10.3969/j.issn.1000-3428.2012.17.010It is the requirement to research data replica storage and management technology for improving the reliability and efficiency of massive data in complex network like the cloud computing. The game theory is used to analyze the replica creation problem, and its basic model in complex network based on game strategy is proposed. The existence of pure strategy Nash equilibria in basic model is proved, and the results are analyzed through simulation. The method is of reference value for improving the usability and efficiency of massive data.
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Computer Engineering. 2012, 38(17): 38-41. https://doi.org/10.3969/j.issn.1000-3428.2012.17.011This paper presents a formal method based on the model checking to analyze the survivability. On the basis of giving system environment and the main services, the survivability system is modeled on introducing the factors of disaster and error. The system’s survivability requirement is determined and converted to the modal logic. It takes the telephone access network as an example, the method is implemented by the PRISM, and results show that the model checking can regulate, and simplify the survivability analysis process.
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Computer Engineering. 2012, 38(17): 42-45,48. https://doi.org/10.3969/j.issn.1000-3428.2012.17.012A test suite generated using complete Finite State Machine(FSM) has excellent fault detection ability, but it is astronomically large. This paper presents six heuristic method to reduce the size of the FSM model based on the general requirements from the access control system. These methods not only avoid the state explosion, but also simplify the generation of conformance test suite size. This paper designs experiment based on spanning tree of the FSM. Experimental result shows that using improved FSM to reduce the comformance test suite of Role-based Access Control(RBAC) system is effective.
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Computer Engineering. 2012, 38(17): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2012.17.013In Tibetan, followed ingredients appear with high frequency. Suffix-cut appears in the participle word. It affects the accuracy of the word. By applying word(morpheme) + suffix method, Tibetan suffix and prefix word(morpheme) are grouped into a slitting unit output. In response to a large number of names, place names, unit names, and so on appear in Tibetan, which are not included in dictionaries, debris splitting phenomena appears in the word. Aiming at the problem, it uses word fragments consolidation method. Multiple occurrences of the term debris are to be grouped into a slit unit output. Experimental results show that two methods can improve the accuracy of Tibetan word segmentation.
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Computer Engineering. 2012, 38(17): 49-51,55. https://doi.org/10.3969/j.issn.1000-3428.2012.17.014As a result that the traditional mobile database model can not adapt to the actual situation of Ad Hoc network, this paper improves the traditional mobile database model with adding a local server as the agent to adapt to the situation of Ad Hoc network, forming the mobile database model which comprises mobile computer, local server and master server. Furthermore, two algorithms which are used to solve problems of transactions redoing and data synchronization between local server and master server are proposed, so that mobile computer can access database efficiently and correctly. Experimental results show that mobile database model can gain good stability.
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Computer Engineering. 2012, 38(17): 52-55. https://doi.org/10.3969/j.issn.1000-3428.2012.17.015This paper puts forward a new relatively reasonable formula measuring attribute significance based on inconsistent dominance object information systems. On this basis, a new heuristic algorithm based on lower approximation for reduction of attribute is proposed. Compared with those existed algorithms, its flexibility is increased because calculating the important value of unimportant attributes repeatedly can be avoided by removing unimportant attributes gradually from the search space, and this algorithm is much less time complexity than those existed algorithms. Example illustrates the effectiveness of this algorithm.
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Computer Engineering. 2012, 38(17): 56-58,62. https://doi.org/10.3969/j.issn.1000-3428.2012.17.016Existing complex network community algorithms mostly take the global modularity as a criterion of searching the best community structure. However, it is revealed to suffer a resolution limit that may fail to discover small known qualified communities and discover some unqualified communities. Aiming at this problem, combining weak community definition, local fitness and global modularity, this paper presents a new multi-objective integer programming model and an efficient heuristic algorithm. It successfully discovers networks’ hierarchical and overlapping community structure. Experimental results show that the algorithm overcomes the disadvantages and fully discovers small communities with high efficiency.
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Computer Engineering. 2012, 38(17): 59-62. https://doi.org/10.3969/j.issn.1000-3428.2012.17.017An Energy-Balanced Clustering routing protocol of Two-Layer hierarchy(TL-EBC) for Wireless Sensor Network(WSN) is proposed. TL-EBC is a centralized clustering protocol of two-layer hierarchy, which is compact, energy-aware and energy-consumption-balanced. In the lower layer of the protocol, the optimal clustering of all nodes using the Particle Swarm Optimization(PSO) algorithm is realized. And in the upper layer, the chief-cluster-head, which is responsible for collecting, aggregating the data of all cluster heads and sending the fused data to the base station, is selected. Simulation results show that the protocol can efficiently decrease the dead speed of the nodes and prolong the network lifetime.
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Computer Engineering. 2012, 38(17): 63-65. https://doi.org/10.3969/j.issn.1000-3428.2012.17.018To realize the lost data source recovery or local recovery of Ad Hoc multicast networks, this paper defines grouping cache efficiency and remaining cache efficiency index. On the analysis of the optimal cache problem, it presents a caching optimization strategy Optimal Cache Time(OCT), through the distributed cache algorithm make the system as approximation of the theory optimal value. Experimental result shows that OCT can obviously improve the performance of multicast network and decrease the latency of data loss recovery.
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Computer Engineering. 2012, 38(17): 66-69. https://doi.org/10.3969/j.issn.1000-3428.2012.17.019This paper proposes a self-organizing networking model based on bouncing and cluster merging strategy. It uses the reflection theorem of light in physical to decide the nodes’ moving directions with the aim of forming a network in a distributed manner, and adopts the analogy method of cellular automaton to research the networking performance of this model. Experimental result indicates that this model has obvious advantages compared with the Random Waypoint model in the aspect of networking speed.
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Computer Engineering. 2012, 38(17): 70-72,76. https://doi.org/10.3969/j.issn.1000-3428.2012.17.020At the system of signal combining, the frequency difference between the signal error can not be ignored, and it reduces the estimated accuracy of the phase difference, affects the quality of the synthesized signal. So this paper uses a sampling point before and after L/2 data to estimate the compensation that point out of phase, and point by point in order to run, avoids the deviation of the phase difference time-varying compensation. Analysis through the derivation of the residual frequency difference Δf phase estimation accuracy when the product of the length L of the cross-correlation data and the normalized frequency difference Δf /fs approximately 0.37, it is estimated that the highest accuracy. In the practical application of the selection of L there is certain guiding significance.
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Computer Engineering. 2012, 38(17): 73-76. https://doi.org/10.3969/j.issn.1000-3428.2012.17.021When the Border Gateway Protocol Multi-protocol Label Switching Virtual Private Network(BGP/MPLS VPN) multicast link fails, the multicast tree is divided into unconnected sub-trees. In reaction to this phenomenon, this paper gives an idea that backup-path can be used to connect sub-trees and reconstruct multicast tree so as to reduce offline probability weighted host number because of link failure. When the backup-path is established, the effect of invalid link on multicast tree is the important factor which determines the robustness of multicast tree, and it can be minimized by the deigned algorithm of choosing multicast backup-path, thus increasing the robustness of multicast tree. Analysis result shows that this algorithm can realize the fine recovery of invalid multicast link.
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Computer Engineering. 2012, 38(17): 77-80,83. https://doi.org/10.3969/j.issn.1000-3428.2012.17.022In order to improve the backoff algorithm of IEEE 802.11, this paper analyzes several algorithms, and introduces the change rate relative of collision frequency and successful transmission, for the scale of the current congestion of network. The algorithm adjusts contention window according to the two elements above, and reduces the contention of access and ameliorates the performance of network. NS2 simulation result proves that the algorithm can adapt the change of network load, improve the throughput and monish the packet drop rate and end-to-end delay.
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Computer Engineering. 2012, 38(17): 81-83. https://doi.org/10.3969/j.issn.1000-3428.2012.17.023For utilizing the characters of high-security and ant-intercepting about chaotic sequence, this paper designs a scheme of chaotic spread- spectrum communication based on phase offset. In the sending end, the data is sent in the format of frame. The information of phase offset is periodically sent to the receiver by differential chaotic phase-shifting keying. The receiver demodulates the information of phase-offset. By comparing the phase offset-difference of the two chaotic sequences, the receiving sequence and the local sequence, the receiver accelerates or delays the local chaotic iteration in order to achieve synchronization and demodulation. Simulation results show that chaotic spread-spectrum signal can be received at any time by the scheme and correctly demodulated, and the spread-spectrum system has good ant-jamming performance.
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Computer Engineering. 2012, 38(17): 84-86,90. https://doi.org/10.3969/j.issn.1000-3428.2012.17.024Status for inevitable errors, this paper puts forward reverse correction ideas and lists all possible combination of block codes and packet interleaving modes using enumeration methods. And the decoding is used for correcting the errors. The right parameters of interleaving come out. This paper simulates the method in different Bit Error Rate(BER) and reaches an appropriate range of bit error rate.
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Computer Engineering. 2012, 38(17): 87-90. https://doi.org/10.3969/j.issn.1000-3428.2012.17.025An adaptive Load Balancing Clustering Algorithm(ALBCA) is proposed to resolve the problem that HEED mini-degree clustering algorithm has too many single-node clusters and too big clusters. The ALBCA adjusts reasonable bound of cluster size to connectivity status of the network adaptively and lets single node clusters join in non-single node clusters within two hops. Simulation results show that ALBCA gets more balanceable clusters than HEED mini-degree in different network connectivity circumstances.
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Computer Engineering. 2012, 38(17): 91-93,97. https://doi.org/10.3969/j.issn.1000-3428.2012.17.026Data gathering is a key problem in Wireless Sensor Network(WSN), the current tree-based data gathering methods often result in some problems, such as the load imbalance, the uncontrolled height of the tree, the larger delay of data gathering and so on. To solve this problem, this paper proposes a new algorithm DSDA((Delay Bounded Data Gathering). The algorithm constructs a Fewest Hops Tree(FHT). It iteratively adds an edge to the tree, and it satisfies with user’s requirement for delay by limiting tree’s height, and it can extend the tree lifetime by making the degree of nodes in the tree which is decreased to the minimum. Simulation results show that the algorithm can construct a tree under limited tree’s height, which has longer lifetime than previous protocols.
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Computer Engineering. 2012, 38(17): 94-97. https://doi.org/10.3969/j.issn.1000-3428.2012.17.027This passage proposes a Multiple-plane and Multiple-stage(MPMS) self-routing model with group sorter switching fabric based on MPMS currency framework. It uses cell state to depict de-multiplexer, multiplexer and switching cell, uses group sorter Banyan-type to depict switching plane, and uses bit-permuting to depict stages exchange. It deduces the guide transform of different Banyan-type switching fabric and blocking probability iterative algorithm based on the self-routing model, and puts up emulation experiment whose result is that time delay of MPMS self-routing model is lower than Bandwidth Guaranteed Concurrent Round-robin Dispatching(BG-CRRD) when load intensity is low, the blocking probability of MPMS self-routing model is >10–2 when load intensity is high, which increases the time delay.
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Computer Engineering. 2012, 38(17): 98-101,105. https://doi.org/10.3969/j.issn.1000-3428.2012.17.028To tackle the problems of existing clustering algorithms, such as the assumption of unique ID in the whole network and unstable cluster structure etc., a clustering algorithm for Ad Hoc network based on stability degree is proposed. This algorithm removes the assumption of the unique ID though the stability degree based clustering algorithm, and converges fast, and the cluster structure built by this algorithm has better stability and continuity. Analysis and simulation verifies that the algorism has high packet delivery ratio and low routing overhead.
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Computer Engineering. 2012, 38(17): 102-105. https://doi.org/10.3969/j.issn.1000-3428.2012.17.029A high-capacity lossless information hiding algorithm based on adjacent pixel differences of image block is proposed, which can recover the original image in lossless way after the hidden data are extracted from the stego image. It divides a cover image into a number of non-overlapping blocks, and sequences of pixels are obtained by scanning each image block in a given order. Pixel difference histograms are obtained by calculating adjacent pixel differences in each sequence. And the two maximal peak points in each pixel difference histogram are used to embed secret data. Experimental results show that compared with other lossless data hiding algorithms, the proposed algorithm can achieve large data hiding capacity and high PSNR while keeping image quality of the stego image high.
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Computer Engineering. 2012, 38(17): 106-109,115. https://doi.org/10.3969/j.issn.1000-3428.2012.17.030For the cryptographic algorithm recognition problem in the current network security, this paper puts forward a method of cryptogram algorithm recognition based on dynamic binary analysis. It uses DynamoRIO platform to record data flow information during the execution of the program dynamically, and uses some technologies comprehensively to recognize cryptographic algorithm, such as filtering and classification based on statistical features, signature matching based on constant characteristics of cryptographic algorithms and parameter identification based on data flow analysis technology. Test result shows that it can identify and locate the cryptographic algorithm in application quickly and accurately.
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Computer Engineering. 2012, 38(17): 110-115. https://doi.org/10.3969/j.issn.1000-3428.2012.17.031Because an error condition may be added in BAN logic reasoning process, unsafe protocol can be verified safe. In order to solve the problem, this paper improves the formal description of message. An implicit but essential condition is added in the message-meaning inference rule, so that reliability of verification is enhanced. By defining message units of sending and reasoning, freshness rule is suitable to more kinds of protocols in safety verification.
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Computer Engineering. 2012, 38(17): 116-118. https://doi.org/10.3969/j.issn.1000-3428.2012.17.032Almost proxy re-signature schemes are hardness of big integer factoring problem and Discrete Logarithm(DL) problem. But the quantum computer can solve this question in polynomial time, which may cause potential security risks to the schemes. This paper uses the characteristics that multivariate public key cryptography can resist quantum computer attack, to design a new proxy re-signature scheme. Theoretical analysis shows that the scheme fits internal and external security, and it is efficient.
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Computer Engineering. 2012, 38(17): 119-122. https://doi.org/10.3969/j.issn.1000-3428.2012.17.033There are some shortages of existing API-calling obfuscation technology in the fight against the static analysis, such as weak versatility, easy to analyze and so on. This paper proposes a binary code obfuscation method. By using opaque constants based on 3SAT, it builds obfuscation transformations that change the objective address of API-calling to indirect and ensure the address invariable, which makes analyzing API address be an Nondeterministic Polynomial(NP) complete problem, so that the address can not be obtained by static analysis. Experimental results show that the difficulty of analysis of obfuscated program is enhanced, and the method can evade the static detection method based on API-calling.
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Computer Engineering. 2012, 38(17): 123-125,128. https://doi.org/10.3969/j.issn.1000-3428.2012.17.034Plateaued function has high nonlinearity, satisfy correlation immune and balanceness, and is applied widely in cryptographic function field. Based on a construction method of single-output Plateaued function proposed by Carlet etc, this paper uses state transition matrix of m-sequence to construct a class of multi-output Plateaued function. By referring to lemma 5 in Johansson’s paper to propose another construction method of multi-output Plateaued function. The functions got are suitable to design S boxes, filtering(combination) functions, hash functions and so on.
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Computer Engineering. 2012, 38(17): 126-128. https://doi.org/10.3969/j.issn.1000-3428.2012.17.035NTRU-class digital signature schemes have a common weakness that signature value leaks some information on the private key. Aiming at this weakness problem, a novel NTRU-class digital signature scheme is created. In the new scheme, a cyclic lattice is generated by using private key, the signature value of the message hashed is the closest vector in the cyclic lattice by using the Gaussian sampling algorithm. Compared with the exiting schemes, the new scheme remains the efficiency of the signature and the verification. This paper obtains following two new results about the novel scheme: (1)The hardness of forging a signature is based on the hardness of the closest vector problem over the cyclic lattice; (2)The distribution of the signature values by using the Gaussian sampling algorithm in the novel scheme is spherical in the space and leaks no information about the private key.
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Computer Engineering. 2012, 38(17): 129-132. https://doi.org/10.3969/j.issn.1000-3428.2012.17.036A polyclonal network clustering algorithm for training the network data is employed to build a unsupervised abnormal detection system. It is directed by the affinity function between antibody and antigen. Some artificial immune system operators are used in the method including immunodominance, clone, cross, non-uniform mutation and forbidden clone. A small-size, self-adaptive and self-learning network is evolved in the method to reflect the distribution of original data. A traditional hierarchical agglomerative clustering algorithm is employed to perform clustering analysis and obtain the classification of normal and abnormal data. Simulation results show that the algorithm can deal with massive unlabeled data to detect anomaly and even can detect unknown attacks.
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Computer Engineering. 2012, 38(17): 133-135. https://doi.org/10.3969/j.issn.1000-3428.2012.17.037According to the characteristics of network video such as large quantity of data, high requirements of compression and various store styles, this paper presents an encryption algorithm combing Rijndael algorithm with video data compression coding. The video data are encrypted after transformation, quantization and before compression. By using Rijndael algorithm, it recovers the statistical properties of the encrypted data to maintain the same compression ratio with the encoded data which is not encrypted. Experimental results show that the algorithm can improve the security of video data, and ensure quality and high compression ratio of the video.
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Computer Engineering. 2012, 38(17): 136-138,141. https://doi.org/10.3969/j.issn.1000-3428.2012.17.038Based on LSB algorithm, linear block coding and wet paper coding, this paper presents a new high-efficiency steganographic algorithm. The secret message is embedded into the cover data through three layers: In the first layer, secret message is carried by cover data based on LSB steganographic algorithm. In the second layer, using wet paper coding to select the direction of modification, the paper embeds secret message with F5 on the cover data. The wet paper coding takes the third part of secret message in the third layer. Analysis result shows that the algorithm has more capacity with same embedding efficiency.
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Computer Engineering. 2012, 38(17): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2012.17.039Aiming at the delegatability and inefficiency problems of current identity-based strong designated verifier signature schemes, a new efficient identity-based strong designated verifier signature scheme is proposed, which includes signature scheme based on bilinear pairings, security proof and efficiency analysis, performance analysis results show that the new scheme can satisfy the security requirements of non-transferability, unforgetability, non-delegatability. Compared with other existing schemes, the new scheme which reduces the computational cost of bilinear pairings and modular multiplication is more efficient.
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Computer Engineering. 2012, 38(17): 142-144,147. https://doi.org/10.3969/j.issn.1000-3428.2012.17.040Based on the research of the current trust models in P2P network, this paper finds the shortcoming of the malicious nodes in the current models, the malicious behavior of these malicious nodes is analyzed, the advantages of many other models are integrated, according to the principle of “slow raising and fast descending” and direct trust has greater impact, especially considering the control of some malicious nodes, one new trust model is put forward. In this model, the trust value is related to the size of the resource after each transaction. Simulation experimental result shows the validity and superiority of the new model, this model can make the transaction success rate enhance greatly.
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Computer Engineering. 2012, 38(17): 145-147. https://doi.org/10.3969/j.issn.1000-3428.2012.17.041Distributed Denial of Service(DDoS) is one of the most serious network attacks. this paper proposes a secure defense model based on digital ant for Web information system. By computing the resources correlation of peers by Ant Colony Optimization(ACO) algorithm, a defense alliance model against DDoS is constructed. A defense mechanism with swarm intelligence and concertedness is realized, which includes certaining DDoS attack method, tagging datagram and limiting flows.
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Computer Engineering. 2012, 38(17): 148-151. https://doi.org/10.3969/j.issn.1000-3428.2012.17.042Hyper-chaotic system image encryption algorithm HYPER_HIE uses elementary transformation and exjunction to encrypt, so it is difficult to resist various attacks. Aiming at three steps of HYPER_HIE including key generation, pixel scrambling, image diffusion and confusion, this paper chooses three kinds of plaintext matrixes to do chosen plaintext attack without knowing encryption key. An instance shows that the attack method can decode ciphertext with low computing costs.
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Computer Engineering. 2012, 38(17): 152-156,161. https://doi.org/10.3969/j.issn.1000-3428.2012.17.043To ensure the security of the transaction in P2P network, a new network security model based on classification management of trading nodes is proposed. Through classification statistics of failure events in the trade between the local node and other nodes, the trade failure events are divided into malicious attacks, bad quality and so on, so that malicious nodes can be detected and controlled timely and correctly. According to transaction history records, Support Vector Machine(SVM) classifier is used to divide trading nodes into trust nodes, strange nodes and malicious nodes. The trust node list and the malicious node list are established to exclude the malicious nodes from trading. According to the statistical data of feedbacks from the other nodes, Bayesian classifier is used for the classification of the evaluated nodes. The model dynamically counts the feedback behavior condition, divided the feedback behavior into the honest feedback, the malicious feedback and so on. Experimental results show that compared with the existing trust model, the model proposed can obtain higher examination rate over malicious acts and the higher transaction success rate.
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Computer Engineering. 2012, 38(17): 157-161. https://doi.org/10.3969/j.issn.1000-3428.2012.17.044For problems which the whole trajectory as the target for the clustering, this paper proposes a clustering algorithm called CTIHD(Clustering of Trajectories based on Improved Hausdorff Distance), which uses a sub- trajectory as the target for the clustering. In this algorithm, in order to effectively calculate the similarity between the trajectory, the algorithm defines a new sub-trajectory distance metrics, the definition can not only effectively eliminate the public error between sub-trajectory, but also take full account of sub-trajectory contains the movement feature. In algorithm, trajectory is divided into sub-trajectories uses the concept of the trajectory of feature point, It uses the proposed the definition of trajectory distance metrics between sub-trajectories to calculated similarity between sub-trajectories; On this basis, the use of traditional clustering methods for sub-trajectory clustering. Experimental results show that the algorithm can achieve better trajectory clustering effect than the existing methods.
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Computer Engineering. 2012, 38(17): 162-165. https://doi.org/10.3969/j.issn.1000-3428.2012.17.045In order to improve the classification rule accuracy of the classical Ant-miner algorithm, this paper proposes an improved Ant-miner algorithm for classification rule mining. Heuristic function with sample density and sample proportion is constructed to avoid the bias caused by the same probability in Ant-miner. A pruning strategy with mutation probability is emploied to expand the search space and improve the rule accuracy. An evaporation coefficient in Ant-miner’s pheromone update formula is added to slow down the convergence rate of the algorithm. Experimental results on UCI datasets show that the proposed algorithm is promising and can obtain higher predication accuracy than the original Ant-miner algorithm.
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Computer Engineering. 2012, 38(17): 166-170. https://doi.org/10.3969/j.issn.1000-3428.2012.17.046Detection of salient region is useful for many computer vision applications, such as image segmentation, object recognition, image retrieval, adaptive compression and so on. This paper proposes a new salient region detection algorithm based on frequency and spatial domain analysis. It suppresses the non-salient regions by different window sizes, selectes the best saliency map by spatial information. The final saliency map removes background and highlights the entire salient object. Experimental results show that the proposed algorithm outperforms the 5 typical methods.
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Computer Engineering. 2012, 38(17): 171-173. https://doi.org/10.3969/j.issn.1000-3428.2012.17.047In order to solve the crux for sample’s label and implement active learning in network environment, the network flow identification method is presented by using Support Vector Machine(SVM) with posteriori probability. The sample’s posteriori probability is got by the output of SVM and Sigmoid function. It uses the larger of the two 2 class probability information entropy to measure the sample Effect Score(ES). By means of SVM and uncertainty sampling strategy, it realizes the active learning process, and traffic identification’s model is formed. Experimental results show that the method can achieve better identification result.
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Computer Engineering. 2012, 38(17): 174-177. https://doi.org/10.3969/j.issn.1000-3428.2012.17.048There are many redundant feature points by multi-scale Harris method to check. Although Harris-Laplace method can remove some redundant points, there still are more than one feature points in a local structure or a few different scale local structures represented a feature points. This paper present an improved method of checking Harris-Laplace feature points, that track and group it while checking feature points so that some feature points that represent the same local structure are divided into a group, then use Laplace function to remove redundant feature points and the corner measure to select the most representative of the local structure of the corner. It is proved by experiments that the method can effectively remove redundant feature points. While fuzzy and rotation transforming, the method is better than Harris-Laplace, and has a scale-invariant features.
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Computer Engineering. 2012, 38(17): 178-181. https://doi.org/10.3969/j.issn.1000-3428.2012.17.049To reduce the possibility of falling into local optimum, metroplis rule and differential evolution operator is introdued in Group Search Optimization algorithm, which makes the variation of the algorithm get rid of the shackles of the local extreme advantage, maintain the pre-fast search feature, and improve global search capabilities. During varation and iterative, merit-based evolution improves optimization performance. Test results point that the ability to improve the global convergence of the algorithm is significantly improved, meanwhile, simulation results show that the individual has a good artificial intelligence, which can simulate group behavior toralistically.
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Computer Engineering. 2012, 38(17): 182-185,188. https://doi.org/10.3969/j.issn.1000-3428.2012.17.050As for the difficulty of classifying visible foreign body with little size and complex shapes in healthy wine, a hybrid classifying method using neural network based on visible foreign body characteristics is proposed. The hairs are detected by the single-layer perception. Other kinds of particles are classified by BP neural network. In order to improve the BP network training speed, an improved learning algorithm with adaptive momentum factor and learning rate is presented. Experiment results show that this hybrid classified method has high accuracy and fast identification speed .
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Computer Engineering. 2012, 38(17): 186-188. https://doi.org/10.3969/j.issn.1000-3428.2012.17.051This paper researches Alpha-Beta search algorithm. According to the characteristics of Gobang, it proposes a local search method, thereby directly reducing the search node branch number; combined with the fact that Alpha-Beta algorithm efficiency is highly relevant to the child node order, this paper proposes the static evaluation heuristic and iterative deepening methods for optimization of move ordering. Experimental results show that this method enhances the efficiency of Alpha-Beta search algorithm.
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Computer Engineering. 2012, 38(17): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2012.17.052The lack of public corpus is a big problem in the research of Chinese NLP. To eliminate the effect that lack of corpus to Chinese NLP, this paper presents a Chinese noun phrase coreference resolution system based on an unsupervised clustering approach and gives the details of the platform. The method adoptes three tools to evaluate the performance of the platform, in the case of auto, the average of F-measures achieves 59.43%. Experimental results show that the platform achieves good performance.
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Computer Engineering. 2012, 38(17): 192-195. https://doi.org/10.3969/j.issn.1000-3428.2012.17.053This paper proposes a Geodesic Active Contours(GAC) model accelerated by the Vector Field Convolution(VFC) external force, which takes advantage of parameters active contour models and geometric ones. Based on the advantage of the external forces field, the bi-directional boundary attractive force and the adaptive expansive force are introduced in the model, so it can adaptively adjust the direction of the evolution curves. Experimental results show that the model overcomes the defect that parameters active contour models can not handle topology change of target structures, and the weakness of one-side evolution of the traditional GAC model. Moreover, the model can also extract the concavity boundaries, and is robust to the image noise, weak edges and the initial contour of the model.
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Computer Engineering. 2012, 38(17): 196-200. https://doi.org/10.3969/j.issn.1000-3428.2012.17.054Traditional Scale Invariant Feature Transform(SIFT) feature matching algorithm is based on global search, so bad real-time performance is always shown and mismatches always exist in regions with similar textures. This paper proposes a SIFT feature matching algorithm based on Normalized Cut(Ncut). It puts forward a novel matching method for SIFT feature based on Ncut in the scene of moving objects. It breaks every SIFT feature into its most prominent moving groups and does feature matching respectively between related groups. The proposed algorithm reduces the range of searching and the experimental results show that it provides higher matching efficiency and higher matching accuracy in regions with similar textures. It achieves stable real-time SIFT feature matching between adjacent image frames.
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Computer Engineering. 2012, 38(17): 201-204. https://doi.org/10.3969/j.issn.1000-3428.2012.17.055The accuracy of the existing sentence similarity algorithm needs to be improved, so this paper improves Vector Space Model(VSM) algorithm, adds some syntactic information and semantic information in the traditional VSM for computing sentence similarity. Meanwhile, it designs and realizes a financial Frequently Asked Question(FAQ) question answering system. The system computes sentence similarity by the improved VSM algorithm and returns the answer of users’ question. Experimental result shows that this algorithm has higher accuracy in computing sentence similarity.
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Computer Engineering. 2012, 38(17): 205-208,213. https://doi.org/10.3969/j.issn.1000-3428.2012.17.056Traditional corner detection algorithm can not extract the interested feature point. In order to solve this problem, this paper proposes a new template matching algorithm. In this paper, the special points of airplane image are gotten by curvature corner detection algorithm as the matching image. Template matching algorithm is used to extract the best match points. The features of the image with different illumination conditions and shooting angles are extracted and matched. Experimental results show that the algorithm has better adaptability, and improve the accuracy of matching.
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Computer Engineering. 2012, 38(17): 209-213. https://doi.org/10.3969/j.issn.1000-3428.2012.17.057Traditional method of significant area obtaining can not adapt the size of real objects, have redundant information, and the application scope is limited. In order to solve the problems above, this paper proposes an extraction method of salient object in multi-object scene. It clusters the saliency map obtained by space-based model to divide the multi-object scene into several sub-scenes, and introduces a transference of attention mechanism on the sub-scene sets and the object-based model in order to extract salient objects. Experimental results show that the proposed method can completely and correctly extract the multi-object of the images.
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Computer Engineering. 2012, 38(17): 214-217,225. https://doi.org/10.3969/j.issn.1000-3428.2012.17.058An improved player tracking algorithm based on multi-feature adaptive fusion is proposed to solve existing problems that the model-based tracking method is difficult to deal with greater change of players’ form in football video. This paper uses the adaptive Gaussian mixture model to detect football playfield and players. The Bhattacharyya distance of players’ HUE color features is used to distinguish ownership of the team instead of traditional template matching methods. The method fuses the color, shape and temporal-spatial feature information of target model adaptively for tracking the players and uses three-point prediction method to solve the complete occlusion between players. Experimental results show that the algorithm deals well with the occlusion between players, and can track robustly when the players’ shape changes greatly.
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Computer Engineering. 2012, 38(17): 218-221,231. https://doi.org/10.3969/j.issn.1000-3428.2012.17.059A method of head behavior recognition based on the analysis of trajectory is presented. It detectes and trackes the face automatically, and calculates parameters of the trajectory of the face. It can achieve the behavior recognition of the head by parameters’ data statistics and analysis. For the problem of the exchange of the long axis and the short axis of the tracking window at the case of up head and down head, it proposes an improved algorithm of the angle between the major axis of the tracking box and the vertical axis. Experimental result shows that the problem of the exchange of the long axis and the short axis have been successfully resolved, and the algorithm can recognize the behavior of the head correctly.
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Computer Engineering. 2012, 38(17): 222-225. https://doi.org/10.3969/j.issn.1000-3428.2012.17.060As the image coupled by the adjacent layer fibers has a sub-pixel dislocation, a super-reconstruction algorithm based on image complementary information is proposed. It makes pixel-level registration by traditional phase correlation, and sub-pixel registration by multi-peak fitting. Four B-spline curves for ultimate interpolation are used to fuse the matched image with the reference image. Experimental results show that the proposed algorithm can effectively raise the spatial resolution with less complexity, and the reconstruction image owns better quality.
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Computer Engineering. 2012, 38(17): 226-231. https://doi.org/10.3969/j.issn.1000-3428.2012.17.061The traditional method to deblur single blurred image required a variety of sparse priori constraints, in order to solve this problem, an adaptive Least Mean Square(LMS) error algorithm for getting the Point Spread Function(PSF) is proposed. This algorithm does not require priori constraints, in the case of only a blurred image, First, get an effective strong edge of the latent image as the input signal of the adaptive filter, while blurred image as the desired signal, then estimate the PSF; In the non-blind deconvolution process, in order to reduce ring artifact of the restored image, an anisotropic regularization constraint term on the latent image is adopted. The experimental results show that the PSF estimation method not only applies to motion blur image, but also applies to defocus blur image and uniform blur image.
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Computer Engineering. 2012, 38(17): 232-234. https://doi.org/10.3969/j.issn.1000-3428.2012.17.062A modified Douglas-Peucker algorithm is proposed aiming at the disadvantages of traditional Douglas-Peucker algorithm such as low running speed and difficulty in program design. In the algorithm, the edge is traversed at a certain step length and the feature points on the edge are gained in order of traversal sequence according to the relation between max distance of points on the edge to line between the start and end point of the selected edge section and the distance threshold. At the same time smoothing effect is good when edges are smoothed between the adjacent two feature points. Experimental results show the improved algorithm can increases speed by ten percent than the traditional algorithm.
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Computer Engineering. 2012, 38(17): 235-237,241. https://doi.org/10.3969/j.issn.1000-3428.2012.17.063Super-resolution reconstruction can be considered as a linear system problem which is ill-posed. Aiming at this problem, this paper discusses the construction of the data fidelity term and regularization term in the respect of regularization solution. By comparing the existing data fusion methods, it proposes a method which takes advantage of both the information between pixels in the same frame and neighboring frames to pick out singular points. In order to enhance the performance of Bilateral Total Variation(BTV) filtering on preserving sharp edges, it incorporates a novel implementation which gives the edges heavier variation weighting value and thus achieve better visional effect. Experimental results confirm the superiority of proposed method in both robustness and image quality.
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Computer Engineering. 2012, 38(17): 238-241. https://doi.org/10.3969/j.issn.1000-3428.2012.17.064In order to express a sparse image better and achieve better de-noising effect, an adaptive threshold de-noising algorithm combined with Fourier Transform(FT) and Non-subsampled Contourlet Transform(NSCT) is proposed. The noisy image is de-noised in Fourier domain, and the remaining noise is filtered out in NSCT domain. It is based on stratified noise estimation and adaptive Bayes threshold, combined with a flexible multi-scale and multi-directional energy correction threshold scheme. Experimental results show that the proposed algorithm can improve de-noising performance.
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Computer Engineering. 2012, 38(17): 242-244,248. https://doi.org/10.3969/j.issn.1000-3428.2012.17.065Traditional Gaussian Mixed Model(GMM) seriously depended on the initial value and it is easily affected by the bias field and noise when segmenting Magnatic Resonance(MR) image. Aiming at this problem, this paper proposes a kind of improved Gaussian Mixed Model(GMM) based on patch information, which can manage the bias field and noise while segmenting the image. It utilizes the Fuzzy C-Means(FCM) method to optimize the initial value and accelerates the convergence. In order to obtain a smooth bias field, it employs the Legendre Polynomials to fit it and merges it to the EM framework. This paper introduces neighbor information of each point to reduce the effect of noise so that slender topological objects can be reserved. Experiments results show that the model can bring out bias field and has good segmentation results.
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Computer Engineering. 2012, 38(17): 245-248. https://doi.org/10.3969/j.issn.1000-3428.2012.17.066Focused on the issue of low efficient of mesh simplification algorithm and appearance feature missing in the case of greatly simplification, this paper presents a mesh simplification algorithm. It uses a watershed algorithm for mesh segmentation to improve the efficiency of the mesh mode and adds related factors of the shape of triangle and the bending degree of adjacent face on the basis of the edge collapse cost function of Garland algorithm to better maintain the appearance feature of mesh model. Experimental result shows that the algorithm has a distinct superiority in the speed of mesh simplification and appearance features.
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Computer Engineering. 2012, 38(17): 249-253. https://doi.org/10.3969/j.issn.1000-3428.2012.17.067Aimed to classification and recognition of helicopter, a helicopter rotor parameters estimation method using micro-doppler characteri- stics is proposed. Motion dynamics and echo models of the blades of helicopter in single frequency are set up. The micro-doppler modula- tion of the blade, the relations of micro-doppler modulation and the rotational speed, the blade length and the number of blades are quantitatively analyzed. It extracts micro-doppler modulation and estimates those parameters methods by smoothed pseudo Wigner-Ville distribution and image processing. Simulation demonstrates the validity of the method.
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Computer Engineering. 2012, 38(17): 254-257. https://doi.org/10.3969/j.issn.1000-3428.2012.17.068Based on the simulation data of subway trains, a new idea to identify the transfer function of trains is proposed. Multi-particle bearing models which are needed in train operation simulation are established by analyzing the force situation of subway trains. The models can be used for studying and computing the force situation of mixed marshalling subway trains. The operation of trains is simulated based on these bearing models. The transfer function of trains is identified applying the least-squares method. Test results show that the obtained motion model of trains is valid.
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Computer Engineering. 2012, 38(17): 258-260,264. https://doi.org/10.3969/j.issn.1000-3428.2012.17.069This paper designs and implements an edge resource management system based on data caching for interactive digital TV services. End system terminal such as set-top box achieves the correct positioning through carouseling service group information. By using dynamic resource management algorithm, the edge resource management system allocates and reclaims IPQAM resources. By using data caching and the max-waiting-length threshold strategy, it ensures high concurrent processing capability, and the use of overtime monitoring mechanism guarantees effective recycling of resources. Performance analysis results show that with data caching, the system significantly improves the concurrency and greatly reduces the average response latency.
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Computer Engineering. 2012, 38(17): 261-264. https://doi.org/10.3969/j.issn.1000-3428.2012.17.070According to the problem of forest fire disaster visualization based on digital earth, forest fire simulation visualization framework is established. Specific spread rendering algorithm is designed, adopting Rothermel fire behavior model and contiguous cellular spread model. An equiangle mesh generation simplification model is proposed. Simulation experiment is carried out. The result indicates the proposed model can simulate forest fire spread process on digital earth and well describe fire spread physics mechanism, which provides disaster analysis and decision support in three-dimensional geographic environment.
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Computer Engineering. 2012, 38(17): 265-267,275. https://doi.org/10.3969/j.issn.1000-3428.2012.17.071According to the poor accuracy of the personnel positioning in mine environment, a mine integrated navigation system based on Radio Frequency Identification(RFID) position correction technology is presented. The difference of the Strapdown Inertial Navigation System(SINS) solver location and the actual location stored in RFID tags is selected as the system observation. At the same time, Kalman filter is used to estimate and compensate the gyro drifts and accelerometer biases existed in SINS. Simulation results indicate that the comprehensive precision of new methods is increased by nearly four times than SINS in 30 min.
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Computer Engineering. 2012, 38(17): 268-271. https://doi.org/10.3969/j.issn.1000-3428.2012.17.072The calculation of the screen in the 3G network, needs to solve the complex logic and numerical computation intensive problem, this paper proposes a centralized dynamic task mapping strategy, which uses message-driven approach to dynamically update the task queues. It can adapt to the scalability of clusters well. For the purpose of measuring the pros and cons of the strategy, this paper proposes a suitable benefit function according to the characteristics of the cluster’s task. Experimental results show that this strategy can be well adapted to the scalability of the cluster and have a good performance on practical task mapping with high revenue and throughput.
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Computer Engineering. 2012, 38(17): 272-275. https://doi.org/10.3969/j.issn.1000-3428.2012.17.073According to security and stability requirements of real-time streaming media transmission, this paper proposes a feature analysis-based detection and filtration approach, which parses feature of message head and call signaling content by the analysis of streaming media transmission protocol and data’s streaming features, and then establishes an intelligent model matching method on the basis of special rules set, to matchingly detect the data packets. Experimental results show that this approach gets comparative advantage in the false positive and false negative rate, and comparied with the 5-tuple data packets detection filtration approach, it provides more effective security filtration of streaming media data packets.
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Computer Engineering. 2012, 38(17): 276-279,283. https://doi.org/10.3969/j.issn.1000-3428.2012.17.074Using traditional programming methods on the TMS320C6000 Digital Signal Processor(DSP) may omit the advantages of parallel instructions, software pipelining and the high-speed performance of intrinsics, linear assembly language and assembly language, so the analysis and solving methods of common problems of instruction storage correlation, circulation abundance, the performance of nested loop and interleaved memory conflicting are provided. The reference experience with fixed-point dot product programs shows that the code running speed can be separately increased by 85.9%, 86.4% and 93.1% after optimized by optimization methods of C programming, linear assembly programming and hand assembly programming.
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Computer Engineering. 2012, 38(17): 280-283. https://doi.org/10.3969/j.issn.1000-3428.2012.17.075Facing the signal missing problem in the indoor Wi-Fi environment, this paper proposes a semi-heterogeneous wireless location method based on hidden state sorting. It introduces Hidden Markov Model(HMM) and hidden state sorting approach, designs the localization method including offline training phase and online localization phase. Experimental results show that this method can achieve 96.3% accuracy within an error distance of 1 meter, greatly solve the signal missing problem of semi-heterogeneous feature vectors, and enhance its practical application capability.
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Computer Engineering. 2012, 38(17): 284-286,289. https://doi.org/10.3969/j.issn.1000-3428.2012.17.076A new precoding scheme is proposed for multi-pair two-way relay system in order to improve system performance. 2K users and one relay node are considered in the system, and each pair user communicates with each other via the relay node. All the channels are independent to each other and follow Rayleigh slow fading. Two time slots are needed for transmission. The Signal to Noise Ratio(SNR) for the relay node and the system mutual information are analyzed, and the power allocation scheme is present. Simulation results show that, compared with the traditional precoding scheme, the information of the proposed scheme is improved by 1.2 bit/s/Hz at SNR 25 dB for the relay node.
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Computer Engineering. 2012, 38(17): 287-289. https://doi.org/10.3969/j.issn.1000-3428.2012.17.077The hyper-L shape title simulation algorithm mainly uses exhaustion method, so it is inefficient and limiting. In order to solve the problem, 3D cartesian coordinate system is used into searching triple-loop network. The simulation algorithm to the hyper L-shaped tile of general triple-loop networks G(N;s1,s2,s3) is presented. It is realized by C++ & OpenGL successfully, the diameter D of triple-loop network and some relevant parameters l, m, n of hyper L-shaped tile can be got. It provides convenience for the further research of triple-loop network. Experimental results indicate that the new algorithm has a higher execution efficiency, and has universal property.
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Computer Engineering. 2012, 38(17): 290-292. https://doi.org/10.3969/j.issn.1000-3428.2012.17.078In order to solve the problem that tags can’t be identified quickly and reliably in the Adaptive Search Matrix(ASM) algorithm, an improved adaptive anti-collision algorithm in Radio Frequency Identification(RFID) is presented. The novel algorithm adopting a new search mechanism uses the information of collision bits to gain the proper prefixes from tags, and then constructs a dynamic search matrix to identify tags. It adjusts the search paths adaptively based on the states of timeslots to decrease the collision timeslots and avoid the idle timeslots. Theory and simulations show that the new algorithm can improve the throughput of system, and enhance the identification efficiency effectively.
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