05 June 2009, Volume 35 Issue 11
-
Select all|
-
Computer Engineering. 2009, 35(11): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2009.11.001Sensor networks which are data-centric networks with special flow convergence pattern are highly vulnerable to the Sinkhole attack. On the analysis of routing feature in the neighboring region of Sinkhole attack point, a novel detection strategy of Sinkhole attack based on convergence degree is proposed. Without any cryptographic algorithms and additional communication cost, the strategy is suitable for various network deployment density, different channel condition and attack power.
-
Computer Engineering. 2009, 35(11): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2009.11.002To solve management complexity problems resulted from the continuously changing service requirements in Service Management Net(SMN), the characteristics and descriptions of services are analyzed based on the view of service function, the service functions are divided, and reusable components are created. A mapping instance is given from service functions to service management components.
-
Computer Engineering. 2009, 35(11): 7-9,12. https://doi.org/10.3969/j.issn.1000-3428.2009.11.003A novel stereo matching algorithm via generating dense disparity map based on image segment is proposed. A robust dense disparity-space image is generated by using sliding window. The watershed algorithm is used to segment the image into several small areas. According to the distribution of dense disparity for each area, the reliability of areas is calculated. By taking the impact caused by the neighbor areas into account, the calculation result is used to generate dense disparity map. The international standard data is used to test the performance of this algorithm. Experimental results show this algorithm can achieve better matching effect.
-
Computer Engineering. 2009, 35(11): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2009.11.004This paper presents a new Receiver Autonomous Integrity Monitoring(RAIM) algorithm based on Probability of Hazardously Misleading Information(PHMI) dynamically allocated strategy. This algorithm is feasible to fuse multi-constellation measurements for integrity monitoring. It also dynamically allocates PHMI among all satellites used to get a solution, which improves the availability of traditional RAIM algorithms at 2% to 3%. With the algorithm, it analyzes the integrity monitoring performance of GPS and GPS/Galileo. Results show that with the new method, unaided GNSS RAIM allows LPV-200 approaches in the future.
-
Computer Engineering. 2009, 35(11): 13-15,1. https://doi.org/10.3969/j.issn.1000-3428.2009.11.005In the design and implementation of a retargetable compiler, RTL is suitable for intermediate representation for retargetable complier, because of its two particular forms, namely internal tree structure and external text expression. Based on double characteristic of RTL, this paper proposes a technique of code generation which is suitable for the design and implementation of retaragetable compiler. By means of tree pattern matching, the mapping relationship of intermediate representation and instruction tree pattern in machine description is built, and the assembly code is generated. With building integrated development environment MD32Builder, it is proved that this technique is easy and feasible.
-
Computer Engineering. 2009, 35(11): 16-19. https://doi.org/10.3969/j.issn.1000-3428.2009.11.006This paper proposes a public key cryptosystem with self-generated certificate. In the system, a user obtains partial private keys from an interaction with a Trusted Third Party(TTP). The user integrates the partial keys to derive a complete private key and the corresponding public key and certificate. The public key certificate is stored by the user in a database run by the TTP. The user is responsible for the management of his own public key certificate, including generation, upload, update, and removal of the certificate. The TTP does not know the private key of the user, even if it is involved in the generation of the partial key. The new system with distributed management of self-generated certificates overcomes the weakness of certificate authority’s integrated management of all certificate in the traditional public key infrastructure.
-
Computer Engineering. 2009, 35(11): 20-22,2. https://doi.org/10.3969/j.issn.1000-3428.2009.11.007According to the characteristics of hands of Chinese ordinary people, a total of 22 force points with different grades(0~10) load are divided through TCM expertise experience. A massage therblig coding glossary gets also established. Applying ergonomic software Jack to revise the elected similar massage case, it analyzes doctor’s hand fatigue values. One patient example of cervical spondylotic myelophthy is proposed to verify the validity of this model and method.
-
Computer Engineering. 2009, 35(11): 23-25. https://doi.org/10.3969/j.issn.1000-3428.2009.11.008This paper analyzes the model of component resource requirement and dependence relations between them which affect the Quality of Service(QoS). It presents a self-adaptive middleware framework which can react to workload changes dynamically and self-adaptively tune server configuration parameters to preserve the application QoS. This framework adopts backtracking algorithms to search for the best configuration to satisfy performance requirement. Results of experiment using information query system as test case show that the application performance can be improved by this framework.
-
Computer Engineering. 2009, 35(11): 26-28,3. https://doi.org/10.3969/j.issn.1000-3428.2009.11.009This paper collects multifarious XML-conscious compression methods which are proposed recently, compares and analyzes the state-of-the-art XML-conscious compression technologies. The result of experiment shows that XMill has the best compression ratio, less compression and decompression times, lower memory consume, and obtains the best even compression performance. But it does not support to query compressed document directly. On the other hand, the compression performance of XGRIND and PRESS are far worse than XMill, but they support to query compressed document directly. It points out their merits and deficiency, and discusses further works.
-
Computer Engineering. 2009, 35(11): 29-31. https://doi.org/10.3969/j.issn.1000-3428.2009.11.010Aiming at the problems existed in process of metadata management and application, a novel metadata management and application system is proposed. The system architecture and mechanism of level division are introduced. The storage and management of metadata are implemented by using JAXB technology and O/R mapping framework. The record of metadata is visited and retrieved by using HQL query language. MVC mode is used for the implementation of a prototype metadata search application. Experimental results show this design scheme is effective and feasible.
-
Computer Engineering. 2009, 35(11): 32-34,3. https://doi.org/10.3969/j.issn.1000-3428.2009.11.011The real-time performances of three common middleware technologies such as RTI, EVSM and ACE in distributed interactive simulation environment are tested and analyzed. The differences among them are explained, which probides reference for choosing middleware technology in the distributed interactive simulation system. Through the comparison, some facts are given: middleware technology is produced for distributed computing and processing system. It can make application program depart from operating system, so it becomes the key indicator to envalue the real-time performance of the whole system.
-
Computer Engineering. 2009, 35(11): 35-37. https://doi.org/10.3969/j.issn.1000-3428.2009.11.012Aiming at problems existed in process of parallel compilation for distribution of storage structure in computer system, an exposed-set calculating algorithm to eliminate redundant communication is proposed, which finds exposed-set by analyzing flow dependences and input dependences with array data-flow analysis and self-interfere analysis technologies. Simulation experimental results show that using the results of the algorithm to generate data distribution communication code can eliminate the redundant communication effectively, and improve the performance of the whole system.
-
Computer Engineering. 2009, 35(11): 38-39,4. https://doi.org/10.3969/j.issn.1000-3428.2009.11.013This paper analyzes problems of centralized semantic Web service discovery mechanism, utilizes P2P and ontology technology, and presents a semantic Web service discovery mechanism based on P2P. The deployment and publication of a Web service are bound together. P2P networks are organized into three-layer structure according to application domain and service goal, and three-step service discovery algorithm is established based on this structure to optimize network structure and improve service discovery efficiency.
-
Computer Engineering. 2009, 35(11): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2009.11.014This paper examines the feasibility of InfiniBand technology to design and implement an Effective Parallel File System(EPFS). It designs a transport layer customized for EPFS by trading transparency and generality for performance, buffer management for flow control, dynamic and fair buffer sharing, and efficient memory registration and deregistration. Compared with an EPFS implementation over TCP/IP on the InfiniBand network, the implementation offers better I/O performance if the number of I/O nodes is not bottleneck. Further, two-level memory registration and deregistration technology(AFMRD) works much better than pin-down cache technology.
-
Computer Engineering. 2009, 35(11): 43-45. https://doi.org/10.3969/j.issn.1000-3428.2009.11.015Aiming at the lack of portability problem of multithreading technology in embedded system development, a lightweight general multithreading model called lwThread is proposed, which is developed in pure C language. The threads context switch in standard C statement is implemented. Compared with other thread models, lwThread combines the priority scheduling with dynamic stack allocation in shared-stack pool. This paper also presents a method to determine the maximum stack usage in the shared stack. Experimental results show this lwThread model can improve the efficiency of development and reduce consumption of resources.
-
Computer Engineering. 2009, 35(11): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2009.11.016ConcurTaskTrees(CTTs) is one of the typically task modeling methods of user interface. UML2.0 lacks support for user interface design. Aiming at this problem, this paper transforms CTT into UML2.0. It uses the extension mechanism based on metamodel to extend UML2.0 activity diagram, and builds the metamodel and notations for CTTs. Application results indicate that this method avoids to lose task classification property of CTTs.
-
Computer Engineering. 2009, 35(11): 49-51. https://doi.org/10.3969/j.issn.1000-3428.2009.11.017Aiming at the problems existed in process of data query in Wireless Sensor Network(WSN), a novel query optimization algorithm based on time/energy model is proposed. Each sensor site transmits the query data to server according to the evaluation of the time constraints and the time/energy consumption. Some optimization operations such as compression, merging, and aggregation/fusion are made. Simulation experimental results show this algorithm is effective and can gain better performance.
-
Computer Engineering. 2009, 35(11): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2009.11.018Fuzzy association rules finds association rules based on fuzzy set theory. Frequent items mining is the key problem in data mining. When frequent sets is being searched in Apriori, database needs to be scanned several times, and a large candidate set is checked through pattern matching. The algorithm running efficiency is reduced. Aiming at this problem, this paper proposes Fuzzy Transaction Data-mining Algorithm 2(FTDA2). This algorithm scans database once, and record the transactions, which contribute to the support of frequent set. It compares FTDA2 to other algorithms, and proves its validity by experiment.
-
Computer Engineering. 2009, 35(11): 55-58. https://doi.org/10.3969/j.issn.1000-3428.2009.11.019To conduct space software reliability measure by using the third party test data fully, this paper studies the application of walking through data in software reliability measure. It analyzes some problems such as identification of measure entity, the data transformation from walking through to dynamic failure, and the data integration and the rationality of data application. The corresponding solutions are proposed. Application results indicate that this approach is feasible.
-
Computer Engineering. 2009, 35(11): 59-61. https://doi.org/10.3969/j.issn.1000-3428.2009.11.020This paper introduces new characteristics of Web Service and the related knowledge of Testing and Test Control Notation version 3(TTCN-3). Aiming at the problems when using traditional test methods to test Web Service applications, it proposes a framework and a method of Web Service test based on TTCN-3, and presents the process of testing Web Service with TTCN-3. By giving a case of Web Service test, it illustrates the feasibility of this test method.
-
Computer Engineering. 2009, 35(11): 62-64. https://doi.org/10.3969/j.issn.1000-3428.2009.11.021Aiming at the major factors affecting the performance of mesh networks, this paper uses MIMO and OFDM combination technology to increase the capacity of physical layer. It introduces a method based on a fair and queue and congestion control to improve system efficiency. It uses networks coding to enhance network layer capacity of Wireless Mesh Networks(WMN).
-
Computer Engineering. 2009, 35(11): 65-67. https://doi.org/10.3969/j.issn.1000-3428.2009.11.022Growth Codes is a network coding scheme designed for increasing the persistence of Wireless Sensor Network(WSN) in catastrophic scenarios, but its completely random data exchange results in much transmission redundance. This paper introduces Bloom filter into Growth Codes algorithm to reduce the redundant data exchange. Simulation results show that the improved Growth Codes algorithm outperforms the original algorithm in the aspects of the number of packets exchanged and decoding speed of sink node.
-
Computer Engineering. 2009, 35(11): 68-70. https://doi.org/10.3969/j.issn.1000-3428.2009.11.023Aiming at the problem that locating rare resource is time-consuming with low success rate in unstructured P2P networks, this paper proposes two strategies for rare resource searching: Random Search for Rare resource(RSR) and Flooding and Random Search for Rare resource(FRSR). Based on random walk, RSR modifies request-forward manner by taking the popularity of neighbor nodes into consideration on passing searching request. FRSR combines flooding search with random walk. Simulations show that compared with Random Walk, RSR can reduce response time and communication cost by 22.9% and 22.8%, and improves success rate by 26.2%. Compared with random request passing method, FRSR reduces the response time by 15.4% and improves success rate by 14.2%.
-
Computer Engineering. 2009, 35(11): 71-73. https://doi.org/10.3969/j.issn.1000-3428.2009.11.024Aiming at the problem of Wireless Sensor Network(WSN) with single communication method, this paper designs a WSN sink node based on the processor PXA270 with multi-communication methods such as Ethernet, CF WLAN and GPRS network. It implements the process of the Bootloader transplanting on the hardware platform of sink node, and finishes the experiment and research platform of WSN. Practice application proves that the sink node with multi-communication methods has better practicability.
-
Computer Engineering. 2009, 35(11): 74-76. https://doi.org/10.3969/j.issn.1000-3428.2009.11.025Aiming at the serious energy imbalance of the traditional clustering routing, this paper presents a new clustering scheme, which integrates hierarchical clustering based on classical routing algorithm LEACH. By adopting the multi-cluster head of the bottom level and the multi-hop forwarding mechanism of the top level, it proposes Energy-Efficient Multi-Levels Clustering(EEMLC) algorithm. Simulation results show that the algorithm efficiently improves network lifetime and load balance compared to other algorithms.
-
Computer Engineering. 2009, 35(11): 77-79,8. https://doi.org/10.3969/j.issn.1000-3428.2009.11.026Aiming at the traditional avionics bus can not meet the requirement for rapid and real-time data communication in next generation avionics electronic system, Avionics Full Duplex Switched Ethernet(AFDX) is put forward. This paper introduces the characteristics, architecture, communication mechanism and protocol stack of AFDX network, gives the primary design idea of AFDX end system and network switch, and presents their hardware structure and software flow. It has definite reference and extending value to AFDX communication network.
-
Computer Engineering. 2009, 35(11): 80-82. https://doi.org/10.3969/j.issn.1000-3428.2009.11.027This paper presents a new concept, flag bit, for fault-tolerant routing on Torus multicomputers. It gives a fault-tolerant routing algorithm based on flag bit. Flag bit stored on each node of a Torus keeps faulty information and indicates whether there is an optimal path from the source to the destination. The values of flag bit of nodes can be determined by information exchange between neighbors.
-
Computer Engineering. 2009, 35(11): 83-85,8. https://doi.org/10.3969/j.issn.1000-3428.2009.11.028Based on framework of Wireless Multi-Protocol Label Switching(WMPLS) protocol and characteristic of mobile Ad Hoc network, this paper proposes a multicast protocol RA-WMPLS for Ad Hoc network using WMPLS signaling protocol supporting recovery to establish Label Switch Path(LSP). With label messages and the extending of existing messages introducted to LDP signaling protocol, RA-WMPLS sets up and maintains multicast tree. It realizes multicast function, recovers from a link or node failure, improves network performance. This paper builds an Ad Hoc network simulation model, analyses and compares the performance of RA-WMPLS and ODMRP, and validates its recovery.
-
Computer Engineering. 2009, 35(11): 86-88. https://doi.org/10.3969/j.issn.1000-3428.2009.11.029Aiming at the dynamic nonlinear flow model of TCP in network congestion control of Internet, this paper proposes a congestion control algorithm for Active Queue Management(AQM). It designs a state observer to estimate the unmeasured state, applies the backstepping approach technique and Lyapunov direct method. Closed-loop system is asymptotically stabilized through output feedback. Simulation results show that AQM algorithm based on backstepping approach needs less tuning time, has lower packet loss rate and higher link utilization rate.
-
Computer Engineering. 2009, 35(11): 89-91,9. https://doi.org/10.3969/j.issn.1000-3428.2009.11.030According to the requirements which the service providers desire to increase their services’ revenue, a novel Revenue-based Call Admission Control Algorithm(RCACA) is proposed and solved by the improved heuristic greedy algorithm. The simulation results show that RCACA can meet the requirements of more services in World interoperability for Microwave Access(WiMAX) networks and guarantee the fairness of high-paying services and the revenue-based QoS under the condition of limited bandwidth resources. Furthermore, the service providers’ revenue can be increased and reaches the maximum.
-
Computer Engineering. 2009, 35(11): 92-94. https://doi.org/10.3969/j.issn.1000-3428.2009.11.031In view of the problems in present structural searching techniques, this paper proposes an improved Chord searching algorithm based on grouping grading, which includes grading mechanism based on peer importance and grouping mechanism and devises a searching mechanism with higher efficiency based on Chord searching algorithm. Through comparative experiments on the influence which Chords in different numbers have on the rate of success, searching efficiency and importance grading, it proves that the algorithm improves the searching efficiency.
-
Computer Engineering. 2009, 35(11): 95-97,1. https://doi.org/10.3969/j.issn.1000-3428.2009.11.032A super node based trust model for P2P networks, SuperTrust, is put forward. In SuperTrust, the trust value of a peer from the viewpoint of another in a group is computed based on the reputation, while that of a super peer in the group is evaluated by global trust value. A filtering algorithm is proposed to filter fake, useless and misleading ratings. Simulation result indicates that this trust model can distinguish the malicious node effectively, causes in the P2P network to cooperate the node to have the high success transaction rate under the different malicious node attack pattern.
-
Computer Engineering. 2009, 35(11): 98-100. https://doi.org/10.3969/j.issn.1000-3428.2009.11.033Analyzing advantage and disadvantage of traditional application-level multicast model, this paper proposes a new application level multicast model based on Application Level Active Network(ALAN) technology. It introduces active super nodes, common nodes and active backup nodes into network edge. Multicasts depend on multicast-share tree that is built on WAN, and d-Mesh that is built on LAN. Simulation results with PeerSim show that this model has better performance on Link Stress and RMD compared with Scribe and CAN Multicast, and its advantage will increase with the increasing of network size.
-
Computer Engineering. 2009, 35(11): 101-103,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.034无线局域网；吞吐量；马尔科夫链；优化
-
Computer Engineering. 2009, 35(11): 104-106,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.035This paper researches the influence of connection request sequences to Application-Layer Multicast(ALM) algorithm. It uses the data from the actual project to do experiments, finding that different connection request sequences may cause different ALM multicast tree configuration, so that the performance of multicast tree construction will be affected. Based on the experimental results, it chooses one sequence which ensures the stability of ALM algorithm to low error rate of ALM tree construction.
-
Computer Engineering. 2009, 35(11): 107-109,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.036This paper proposes the Chord routing algorithm based on the main and subordinate structure. The algorithm composes many subrings according to the region. The super node is elected according to the node’s handling abilities in the subring, and each of super nodes constitutes the main ring and connects each other. Each time the routing starts from subring, and then enters the main ring. After the routing jump node is definited, the goal node is searched in the subring to correspond this node. The majority of routing executes in the subring so that the search on the entire P2P ring which moves in the cross region back and forth is avoided and the jump numbers are reduced. The algorithm greatly enhances the routing delay performance.
-
Computer Engineering. 2009, 35(11): 110-112,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.037Considering the unstable traffic of multi-logical links in broadband network access, this paper proposes a model of token scheduling in multi logical links. Token is distributed dynamically in multi-links to make the traffic tend stable and realize traffic load balancing. Simulation results show that the model has better ability of traffic control, which can control the traffic of links according to the demands, and the character of time response and utilization of logical links are improved.
-
Computer Engineering. 2009, 35(11): 113-115. https://doi.org/10.3969/j.issn.1000-3428.2009.11.038The watermark based on Tchebichef moments and wavelet lifting is used in an authentication context. After the discrete lifting wavelet transform, the lower order Tchebichef invariant moments of the sub band coefficients are computed. The processing of the encoder and the decoder is simple, and a few low order moments need to be calculated. The algorithm is compared with the algorithm based on the geometric moments. Results show that the scheme is simple, effective. It has high stabilities of geometrical attacks of rotation, scaling, shearing, and JPEG compression.
-
Computer Engineering. 2009, 35(11): 116-119. https://doi.org/10.3969/j.issn.1000-3428.2009.11.039Mobile storage device has brought the security problem of the sensitive data while enjoying the convenience brought by it. According to the requirement analysis of the security of mobile storage device, a Secure-Mobile Storage System(S-MSS) is designed. The key technology which the S-MSS involves is analyzed, such as the driver of mobile storage device, read-write of the disk sector, the mechanism of data encrypted storage and the strategy setting of virus protection. This paper gives a prototype system, which implements the encryption and protection to the data stored in the mobile storage device.
-
Computer Engineering. 2009, 35(11): 120-122. https://doi.org/10.3969/j.issn.1000-3428.2009.11.040For finding attacks, Snort matches the captured packets with rule chains, therefore the rationality of the rule chains influences the detection speed of Snort greatly. This paper factors out common options from the rule chains, for solving the problem of local accumulation. It sorts the rules according to information quantity of the options. Simulation results of the OPNET shows that the improved rule chains structure can reduce the time of rules matching.
-
Computer Engineering. 2009, 35(11): 123-125. https://doi.org/10.3969/j.issn.1000-3428.2009.11.041Considering the existing watermark method based on transformation region without resisting to geometric attack ability, this paper proposes a method based on binary image, which can against rotation attack ability efficiently. For rotation causing distortion, it makes use of Log-Polar Maping(LPM), which can transform rotation problem in Castesian coordinate to translation property in LPM coordinate. After translation, it uses an exhaustive search to detect test image involves watermark or not. Experimental results indicate that the method can obtain better visual effect, meanwhile, it is robust enough to some image degradation process such as adding noise, cropping, filtering and JPEG compression .
-
Computer Engineering. 2009, 35(11): 126-127. https://doi.org/10.3969/j.issn.1000-3428.2009.11.042Ring signature is a special group signature without credible center and group establishing process, whose signer is anonymous. A parameter implicated in ring signature constructs a ring according to certainty rules. Existing ring signature frameworks provide weak anonymity and strong linkability. Aiming at this problem, this paper presents a ring signature framework which uses random number as linkable label, and provides strong anonymity and weak linkability. The method of using this framework to construct selectively linkable ring signature, verifiable ring signature and efficient deductible ring signature is proposed.
-
Computer Engineering. 2009, 35(11): 128-130. https://doi.org/10.3969/j.issn.1000-3428.2009.11.043Existing algorithms about secure determining are lack of study for situation having prior knowledge. Injecting prior knowledge as secure determining conditions into view publishing algorithm, method of view publishing based on multi-set is proposed. Generating view through thought of generalization and filtration, the loss of precision of data is lowed. View is published within acceptable scope of relative safety and multi-set algorithm is given. Experimental results show that this algorithm can improve publishing view’s security.
-
Computer Engineering. 2009, 35(11): 131-133. https://doi.org/10.3969/j.issn.1000-3428.2009.11.044Model checking is a technique that relies on building a finite model of the system and checks whether the desired properties hold in that model. The check is performed as an exhaustive state space search. This paper introduces a model for L4 microkernel memory management system, gives formal description for operations such as Grant, Map, Flush, proposes and verifies some safety properties using SPIN model checker.
-
Computer Engineering. 2009, 35(11): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2009.11.045A new blind watermark algorithm based on Discrete Wavelet Transform(DWT) and edge mask is proposed to resolve the problem that the subjective image quality is degraded when watermark is embedded into low frequency area. The watermark strength is determined according to masking property in Human Visual System(HVS) and some characters of image, and the watermark location is identified by the technology of edge mask. Experimental results show that the algorithm is invisible and robust against common image processing.
-
Computer Engineering. 2009, 35(11): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2009.11.046Aiming at the problem in real-time speech secure communication system, which is attacked by self-adaptive synchronization control method because of no-load condition key leakage, a new scheme adopting cascaded chaotic system to encrypt the audio’s frequency domain is proposed. The scheme can avoid key leakage, therefore attacks based on self-adaptive synchronization control method can be effectively resisted. The test and analysis results of system indicate that this scheme is more effective and safer than the encryption method in time domain based on single chaotic system.
-
Computer Engineering. 2009, 35(11): 140-142. https://doi.org/10.3969/j.issn.1000-3428.2009.11.047Collaborative system has dynamic and groups characteristics, whose rights management is more complex than the traditional software system. Traditional database system access control mechanism is relatively simple, which is far from satisfying the collaborative system. Aiming at the problems of the complicated authorizing way of access control strategy to shared resource, authorized granularity’s incompact, this paper introduces role mechanism. It applies role-based access control concurrent strategy to system, and puts forward role-based bit mapping system function right algorithm. The algorithm reduces complexity of authority management efficiently and strengthens system’s safety.
-
Computer Engineering. 2009, 35(11): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2009.11.048This paper analyzes the packet filtering technique based on Linux operating system. The packet filtering of Netfilter uses simple linearity graduation algorithm. When the firewall needs to match the number of rules, the performance of firewall falls suddenly, and it becomes the system bottleneck. Therefore, a new packet filtering algorithm based on binary tree and Hash function is proposed, that is B-H. Test proves that the algorithm can achieve the fast match in the massive rules, and enhance the performance of packet filtering greatly.
-
Computer Engineering. 2009, 35(11): 146-147. https://doi.org/10.3969/j.issn.1000-3428.2009.11.049As a result of the disadvantages in the negative selection algorithm and k_continuous_bit mathching regulation, there are detection leaks in intrusion detection system based on immunological principles. The causation of detection leaks are analyzed, and an algorithm is designed to make sure whether a random pattern is a leak. This algorithm provides a valuable scheme to reduce the probability of fail to report intrusion and perfect the function of intrusion detection system.
-
Computer Engineering. 2009, 35(11): 148-149. https://doi.org/10.3969/j.issn.1000-3428.2009.11.050It is proved that an early traceable threshold signature scheme hasn’t the property of traceability. Aiming at the weakness, this paper proposes an improvement to the scheme. Theoratical analysis proves actual signers can be revealed by trusted center to open group signature and also can prove if they join in the signature or not, efficiently prevents forgery attacks and masquerade attacks from inner members of group effectively.
-
Computer Engineering. 2009, 35(11): 150-151,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.051This paper proposes a new gray digital image watermark algorithm based on performances of wavelet transform coefficients. Host image is decomposed into p levels with wavelet, then LLp coefficients is added by scaled gray levels of watermark, then it takes the new LLp coefficients of host image and the unchanged DWT coefficients through wavelet conversely transforming to form watermark image. Experimental results show the algorithm make watermark be good at sightlessness, robustness and low-complexity.
-
Computer Engineering. 2009, 35(11): 152-154. https://doi.org/10.3969/j.issn.1000-3428.2009.11.052Key negotiation needs several times in Wireless Sensor Networks(WSN) because of high loss rate. In order to research the effectiveness of repetitious key negotiations on heightening secure connectivity, it proposes two metrics named the weighing secure connectivity and Cost Performance Ratio(CPR), and it processes the simulation experiments on TOSSIM platform. CPR becomes lower and lower as the number of key negotiations increases. Simulation results and analysis show that 3~4 times repetitious key negotiations are more suitable for high secure connectivity.
-
Computer Engineering. 2009, 35(11): 155-157,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.053Survivable schedule algorithm is one of the important aspects of survivability study. This paper introduces stochastic mechanism to the server cluster systems, which makes it uncertain for the services rotating among the servers, so as to promote the difficulty for the intruders penetrate the systems, and enhances the survivability. It introduces the layers of survivability study, illustrates the function of the survivable schedule algorithm in the study, and analyzes the advantages and disadvantages of the exist algorithms; promotes a pseudo-random autonomous algorithm for service survivability schedule. The performance of the algorithm is investigated.
-
Computer Engineering. 2009, 35(11): 158-160. https://doi.org/10.3969/j.issn.1000-3428.2009.11.054In order to improve the detector collection of generation rate, this paper proposes a kind of improvement chaos negative selection algorithm. Because the Logistic map fold number of times is limited, it uses the chaos sequence which produces from self-map to have a better chaos characteristic. The new algorithm can enhance the production speed of detector collection effectively, cover the examination space well, and has better security.
-
Computer Engineering. 2009, 35(11): 161-162,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.055This paper proposes a Distributed Denial of Service(DDoS) defense method based on Autonomous System(AS) edge feedback. It can thwart attack traffic in boundary of AS, which is close to attacking sources. In attack, the victim measures its ingress traffic rate and sends feedback to the edge routers. As a result, malicious traffic is effectively filtered in AS boundary. The experiments show that the method can effectively guarantee the survival rate of legitimate flows and protect victim from DDoS.
-
Computer Engineering. 2009, 35(11): 163-165,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.056Aiming at the limitation of watermark capacity that traditional Singular Value Decomposition(SVD) watermark algorithm shows, this paper proposes an image watermark algorithm based on SVD. The original image is divided into blocks, and several former Singular Values(SVs) are extracted from each block as the image characteristics, which are used to construct zero-watermark. Simulation experimental results show that the algorithm can reduce caculation complexty, increase the watermark capacity, and perform robustly.
-
Computer Engineering. 2009, 35(11): 166-168,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.057Against the poor adaptability of fixed threshold, a threshold-adaptive Performance Anomaly Detection(PAD) algorithm which can adjust the threshold automatically according to the network environment and operation state is proposed. The method gives an approximate algorithm with unbiased estimation to compute the sample mean and variance of the performance sample space. The algorithm’s time and space complexity reach the degree O(1). The threshold-adaptive PAD can compute a fitting alert threshold by the mean and variance, and measures of noise-smoothing and tremble elimination are used to reduce the problems of fake alarms or missed alarms. The algorithm is applied to the Community Broadband Integrated Services Network Management System(CBIS-NMS) and gets a better result.
-
Computer Engineering. 2009, 35(11): 169-171,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.058Digital Rights Management(DRM) of digital documents is one of the important research fields of DRM. This paper presents a digital rights management scheme of PDF digital documents, whose rights management is based on a kind of dynamic logical license which owns a detailed control methods of document rights and an enhanced security by content grade encryption. The system model, implementation architecture and method are explained. A comparative analysis is showed and an application example is analyzed.
-
Computer Engineering. 2009, 35(11): 172-174. https://doi.org/10.3969/j.issn.1000-3428.2009.11.059Aiming at the problem that the Adaboost algorithm using simple threshold weak classifiers is too weak to fit complex distributions and its slow convergence rate in training, this paper designs a multiple thresholds weak learner. This learner splits the nodes by using biggest reduction in the sum of squares as the partition criteria and builds a weak classifier. It boosts weak classifiers using GAB algorithm on training dataset. Experimental results show that the false positive rate of this method is lower than Adaboost algorithm at the same number of weak classifiers.
-
Computer Engineering. 2009, 35(11): 175-177. https://doi.org/10.3969/j.issn.1000-3428.2009.11.060A particle swarm optimized Simultaneous Localization And Mapping(SLAM) approach is presented, which integrates Particle Swarm Optimization(PSO) into the SLAM. Through the PSO, the prediction of particles is updated, and the particle’s proposal distribution is adjusted, which makes the particles concentrate into the robot’s true pose. Because of the optimization of the particle set, the impoverishment of particle is overcomed effectively. At the same time, the particle number and the computational complexity are reduced. This method is proved correct and feasible in simulation experiments.
-
Computer Engineering. 2009, 35(11): 178-180. https://doi.org/10.3969/j.issn.1000-3428.2009.11.061The multi-sensor technique is applied into the vision system of electronic pet called electronic dog, and a system architecture is proposed, which integrates the recreation and the security capabilities. The flowchart of the system is explained. The method based on first-order difference chain code image and structural pattern recognition theory are introduced. A novel head shape detection method is given. Simulation experimental results show this system gets better performance and has the value of market application.
-
Computer Engineering. 2009, 35(11): 181-183. https://doi.org/10.3969/j.issn.1000-3428.2009.11.062In order to promote the face recognition rate in low-resolution image, from the point of view of practical applications, the relationship between image resolution and face recognition rate is studied, and on basis of which, some face images with different resolutions in three database are recognized by using Principle Component Analysis(PCA) method. Simulation experimental results show this method achieves the fact that the recognition performance under low face image resolution is almost the same as that under high one, and both recognition rate and efficiency are considered.
-
Computer Engineering. 2009, 35(11): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2009.11.063A new vertical search engine-aimed semantic correlation algorithm based on knowledge is presented, which emphasizes knowledge representation technique and semantic association calculation to build up semantic rules. The query recall rate and the retrieval accuracy of both semantic extension and semantic association calculation are promoted. According to the characteristic in fields of agricultural products logistics, the vertical search engine in the Application Service Probider(ASP) platform is designed and implemented.
-
Computer Engineering. 2009, 35(11): 187-189. https://doi.org/10.3969/j.issn.1000-3428.2009.11.064Aiming at the problems in process of fiber video well logging processing, a novel technique of automatic apertures identification and processing is proposed, which uses selective Gauss Laplace edge detection and annular two-way rectangular box scanning technique to implement automatic aperture identification. It corrects apertures information in the database automatically with special algorithm, and estimates whether the aperture produces oil by calculating margin of certain pixel counts. Simulation experimental results demonstrate this technique can get a fast processing speed and high accuracy rate, which has the value of application.
-
Computer Engineering. 2009, 35(11): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2009.11.065Aiming at the discovery problem in outlier data, an improved fuzzy clustering algorithm for outlier kernel is proposed, which uses priori knowledge to select clustering objective function and makes clustering center as initial parameter. The convergence rate of the algorithm is promoted and the whole running time is reduced. Simulation experimental results show this algorithm is effective.
-
Computer Engineering. 2009, 35(11): 193-195. https://doi.org/10.3969/j.issn.1000-3428.2009.11.066This paper presents a method of multi-modal face recognition which combines Local Binary Pattern(LBP) with Fisherfaces. LBP descriptor is used to extract the LBP Histogram Sequence(LBPHS) from grey-level and depth face images. The corresponding linear subspaces are constructed by Fisherfaces respectively. The cosine similarity is adopted as the similarity metric of projected vectors. Weighted sum rule is utilized to fuse 2D and 3D information. The experimental results on FRGC database indicate that the Equal Error Rate(EER) of the proposed method is only 0.33%, which is much lower than fusion of LBPHS with histogram intersection and that of Fisherfaces with cosine similarity.
-
Computer Engineering. 2009, 35(11): 196-198. https://doi.org/10.3969/j.issn.1000-3428.2009.11.067Collaborative filtering algorithm is one of the most successful technology for building personalized recommendation system to date. But traditional algorithm does not consider finding the nearest neighbors in different time periods, leading to the neighbors may not be the nearest neighbor set. For this reason, an enhanced neighbor set personalized recommendation algorithm is proposed. The rating is given a weight by a time gradually decreasing which is weighted to search nearest neighbor. The experimental results show that the presented algorithm can improve recommendation quality of the collaborative filtering recommendation algorithm.
-
Computer Engineering. 2009, 35(11): 199-201. https://doi.org/10.3969/j.issn.1000-3428.2009.11.068Insufficiently penetrates on the present Web service description service function semantics causes the question of service recognition combination ability. This paper proposes a kind of ontology-oriented semantic service functional description method, and establishes the mapping relational model and the grade of service relational model between the ontology. It solves through the difference evolution algorithm, thus obtains a good service component recognition method. Application in the management information system in Jiuzhaigou indicates that the method is superior to the traditional method.
-
Computer Engineering. 2009, 35(11): 202-204. https://doi.org/10.3969/j.issn.1000-3428.2009.11.069Under long time reverberation circumstances, general frequency-domain blind source separation algorithm may converge incompletely, which result in interference signal in separation signal, and the algorithm performance decrease. This paper proposes an improved Wiener filtering postprocessing algorithm according to the sparse properties of speech signal in time-domain and frequency-domain, and by estimating power spectrum density of separation signal and interference signal in separation signal. Experimental results show that compared to the original Wiener filtering algorithm, this algorithm can increase interference signal by 1 dB~2 dB without increasing computation complexity.
-
Computer Engineering. 2009, 35(11): 205-206,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.070Taking account of the uncertain information and the unbalance of link results in the congestion of network, a Genetic Algorithm(GA) with the information entropy is presented to solve the problem in the multicast routing. The algorithm begins from a least-delay tree, searches the max information entropy multicast tree in the multi-population, and gets final multicast tree satisfying delay constraint and the least balance. The results show that the proposed algorithm performs better in terms of delaying a running time against existing heuristics algorithm, and constructs optimal delay-constrained and balance multicast tree efficiently.
-
Computer Engineering. 2009, 35(11): 207-209. https://doi.org/10.3969/j.issn.1000-3428.2009.11.071Aiming at the problem of whitewashing in Peer-to-Peer(P2P) system, a novel incent mechanism is pro¬posed. Using game theoretic analysis, this paper reveals that the conventional Tit-for-Tat(TfT) is not an evolutionary stable strategy in P2P systems with some whitewashers. It also indicates that an improved strategy to integrate an appropriate identity cost into TfT is an effective method to impress whitewashers. Simulation experimental results show this mechanism promotes the performance of the whole system effectively.
-
Computer Engineering. 2009, 35(11): 210-212,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.072Most interpolative reasoning methods in multi-dimension cannot guarantee the convexity and normality of result, and cannot consider weights of each variable influencing conclusion. This paper proposes a fuzzy multidimensional reasoning method based on weight of Precedence Chart(PC), which confirms the weights by Precedence Chart(PC). Experimental results show that it not only reduces the errors, but also keeps the convexity and normality of the reasoning consequence.
-
Computer Engineering. 2009, 35(11): 213-215. https://doi.org/10.3969/j.issn.1000-3428.2009.11.073An estimation method for sinusoidal frequency in strong chaotic noise is presented, which makes mixed signals, containing chaotic signal and sinusoidal signal, into filter, and uses the filtered signal to drive a new response chaotic system same as the driving system. If chaotic synchronization occurs, the error data series between drive and response signal have the sinusoidal signal, and the SNR in error data series is much improved, so it is easy to estimate the harmonic parameter. Simulation experimental results show this method is effective and feasible.
-
Computer Engineering. 2009, 35(11): 216-217,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.074This paper proposes a new Chaos Differential Evolution(CDE) algorithm. It uses Differential Evolution(DE) algorithm to find the best individual each generation, then chaos based local search is executed nearby the best individual. A scaling factor is introduced to enhance the searching ability of CDE. Experimental results on six benchmark functions show the error function value is 10-14, both the ability of finding optimal solution and convergence speed using CDE are better than using DE.
-
Computer Engineering. 2009, 35(11): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2009.11.075Aiming at the feature of Ad Hoc networks and multicast routing problem of Quality of Service(QoS), this paper presents a QoS multicast routing algorithm based on ant algorithm. This algorithm overcomes the disadvantages of ant algorithm such as low convergence speed and local optimal solution by adjusting the rate of pheromone of the worst and the best path. Experimental and analysis results show that a broadcast tree at the near lowest cost and most stable state can be found. This algorithm solves the QoS multicast routing problems of Ad Hoc networks in bandwidth, delay and end-to-end cost.
-
Computer Engineering. 2009, 35(11): 221-222,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.076Aiming at the task allocation problem in Multi-Agent System(MAS), a novel many-to-many allocation mode between task and Agent is put forward and the corresponding mathematics model is established. The performance influence factor is defined, and the objective function is deduced to conduct optimization of task allocation. This method is proved effective through a practical case.
-
Computer Engineering. 2009, 35(11): 223-225. https://doi.org/10.3969/j.issn.1000-3428.2009.11.077Aiming at the characteristics that Image artificial degradation is a reversible process to reduce the visual quality of the target image, this paper proposes a fast artificial image degradation algorithm based on chaos noise, gets the formula to calculate the degree of the degradation, calculates the mean length of lossless predictive coding of the image before and after the degradation, and analyzes the security of the algorithm. It proposes an improved algorithm to defend the image averaging attack.
-
Computer Engineering. 2009, 35(11): 226-227,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.078According to complementation and redundancy of the multi-classifiers in image classification, this paper proposes a novel approach to image classification based on Vague set. Vague set for positive and negative evidences is applied to analyze and optimize the decisions obtained by multi-classifiers. Through integrating two sides of multiple classification decisions, the classification is optimized and synthesized, thus the processing and the results are both powerful and stable. Experimental results show that the performance of the classification is improved.
-
Computer Engineering. 2009, 35(11): 228-230. https://doi.org/10.3969/j.issn.1000-3428.2009.11.079An image fusion algorithm with weighted biorthogonal self adaptive wavelet transform is proposed, which can make up for defects that there are faintness of image details in image fusion of lower contrast image. The adaptive method of wavelet coefficient local model maximum which is weighted is used to fuse the high frequency component, and the syncretic adaptive method is also chosen in the course of fusing low frequency coefficient. The capability of multi-focus image fusion is evaluated by calculating image information entropy and Root Mean Square Error(RMSE). The capability of multi-spectrum image fusion is evaluated by calculating mean grads of image. Experimental results show that the fusion rule of the method is more effective.
-
Computer Engineering. 2009, 35(11): 231-233. https://doi.org/10.3969/j.issn.1000-3428.2009.11.080This paper presents an image adaptive median filtering algorithm by the exploiting of luminance, edge, texture characteristics of the host image. It determines the possible noisy pixels according to the just noticeable difference based on Human Visual System(HVS) masking characteristics, adaptively adjusts the filter window size by the noise density, and removes noisy pixels by improved median filtering algorithm. It can remove salt and pepper noise as well as preserve the detail of images. Experimental results demonstrate that the algorithm is superior to traditional median filters and is particularly effective for the images highly corrupted.
-
Computer Engineering. 2009, 35(11): 234-236. https://doi.org/10.3969/j.issn.1000-3428.2009.11.081G-image representing region homogeneity of Synthetic Aperture Radar(SAR) image is presented. A region growing method is used to segment the image roughly based on the G-image. During the mergence of the rough-segmented image, for the SAR image which has rich direction and texture information, NonSampled Contourlet Transform(NSCT) is employed to extract regional feature and a new method is used to merge regions. Simulation results show the effectivity of the segmentation algorithm for SAR image.
-
Computer Engineering. 2009, 35(11): 237-239. https://doi.org/10.3969/j.issn.1000-3428.2009.11.082This paper proposes an algorithm of video segmentation based on spatio-temporal information for the videos with fixed scenes. In the time domain, it makes use of morphological Tophat filtering to obtain the accurate position of video objects, and in the spatial domain, a clustering algorithm based on t-mixture model and Greedy EM is used to perform segmentation for single frame. By combining the time domain location with the result of spatial domain segmentation, it can correctly obtain the interesting moving target from the video sequence. Experiments show that this algorithm can get better results for theory and application.
-
Computer Engineering. 2009, 35(11): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2009.11.083A single-pass Variable Bit Rate(VBR) rate control strategy is given based on the frame layer for AVS encoding application. This paper allocates bit rate by utilizing the complexity forecast of the GOP layer. It uses the CBR strategy for the frames in the GOP, combines the characteristic of R-D optimizes in AVS and usesa rate distortion model which is accurate but simple to get the quantification parameter. The experimental results show that compared to JVT-H017 in JVT, the method can control the rate accurately, and the computation of the algorithm is lower, moreover, the average luminance PSNR of all testing sequences is improved by about 0.2 dB, and the sample variance of luminance PSNR is about 40% of the JVT-H017 method, which shows the consistency of quality also enhanced greatly.
-
Computer Engineering. 2009, 35(11): 243-245,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.084This paper proposes a self-adaptive shot boundary detection algorithm based on multiple video features. By using sliding window, it compares the frame with its neighbor frames to construct two groups of similar vectors, and using self-adaptive threshold deduced from Fisher discriminator and motion vectors to deal with the problem of abrupt change detection. A finite state machine is used to search gradual transition candidates in intensity variance continuity signal, and verify those to get real gradual transitions. Experimental results based on a large collection of videos from TRECVID demonstrate good performance of the algorithm and its robustness against disturbances caused by object motion or flashlight.
-
Computer Engineering. 2009, 35(11): 246-247,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.085LPC Mel Cepstrum Coefficient(LPCMCC) which comes from LPC Cepstrum(LPCC) changed nonlinear by Mel scale according to human auditory characteristics, thus closer to human auditory system. This paper presents a method based on the feature parameter of LPCMCC, and through using dynamic time warping algorithm to audio data classificate and retrieve. Experimental results show that the accuracy rate of this method is better than LPCC, and the efficiency of retrieval is significantly higher than Mel Frequency Cepstrum Coefficients(MFCC).
-
Computer Engineering. 2009, 35(11): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2009.11.086Aiming at the demand of volume, weight, precision, speediness and function of antenna controller of COTM system, this paper proposes a structure of antenna controller, using the embedded system, and adopts a control project which is ‘gyro stabilization+voltage tracking+error correction’ to enhance the precision of tracking and reduce the cost of system as possible. Results show that this design can improve overall system performance, lower system costs and better meet the actual demand of COTM system.
-
Computer Engineering. 2009, 35(11): 251-253. https://doi.org/10.3969/j.issn.1000-3428.2009.11.087Based on the analysis of PID algorithm and Generalized Predictive Control(GPC) algorithm, the performance index of GPC algorithm is restructured as PID form. The derivation of PID-type Generalized Predictive Control(PIDGPC) algorithm is given. The influence of PIDGPC controller parameter tuning on system performance is analyzed in time domain with simulations in cascade control system for superheated steam temperature in thermal power plant. Compared with conventional GPC algorithm, PIDGPC algorithm has better control performance, and there are good prospects for engineering application.
-
Computer Engineering. 2009, 35(11): 254-255,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.088This paper describes the realization of Modbus RTU master/salve protocol based on SIMATIC S7-300 PLC point-to-point communication module. In a practical packaging control system, data is transmitted reliably and effectively. The scheme is worth promoting economic significance, for avoiding the expense of Siemens driver module of Modbus protocol.
-
Computer Engineering. 2009, 35(11): 256-259. https://doi.org/10.3969/j.issn.1000-3428.2009.11.089This paper developes a full-mode channel estima¬tion for DTMB demodulator. The method utilizes the quasi-cyclic structure of PN sequence guard interval in DTMB system to obtain channel estima¬tion and equalization both in three kinds of frame head mode as well as in single and multi-carrier modulation transmission mode. To implement on hardware, interference cancellation is predigested, equalization and filter for channel impulse response are optimized. The VLSI architecture for channel estimation and equalization is proposed which works effectually and achieves low complexity as well. Computational simulation results show that the proposed scheme has little BER loss in performance.
-
Computer Engineering. 2009, 35(11): 260-262. https://doi.org/10.3969/j.issn.1000-3428.2009.11.090Industrial control system requires industrial Ethernet for high reliability and stability, so it limits the application of industrial Ethernet. In order to reduce the impact of communication failures to the system, this paper adds a redundant link to enhance the availability of communications. Based on Ethernet for Plant Automation(EPA) communication protocol stack, it designs a parallel Ethernet redundancy solution, including system architecture, frame structure and communication procedures, and gives performance analysis.
-
Computer Engineering. 2009, 35(11): 263-265. https://doi.org/10.3969/j.issn.1000-3428.2009.11.091It is hard for communication delay to meet the requirement of real time applications in Network-on-Chip(NoC), and it is difficult to add dynamic elements to the structure of NoC for dynamic reconfigurable System-on-Chip(SoC). To resolve these problems, this paper proposes an on-chip communication architecture named GNLB with the concepts of local communication. It uses network DMA, and utilities network interface that controls on-chip communication to realize effective control for dynamic reconfiguration. Experimental results show that the architecture reduces slices by more than 15.87% and 30.15%, compared to bus-based architecture and Mesh-based architecture. It saves cycles by more than 25% and 14% respectively.
-
Computer Engineering. 2009, 35(11): 266-268. https://doi.org/10.3969/j.issn.1000-3428.2009.11.092In view of the disadvantages that the coming parallel data and no-matching data width induce incontinuous transmission and transmission channel waste when the different property data are transmitted from the top inspector at high-speed opto-electronic theodolite by one single fiber with TDM to the process parts at bottom in practice, this paper puts forward a method of recovering line and field signals of video data, including physical layer protocol implementation of this system. Based on the characteristic of the encode & decode chips, it uses the way of recovery time signal and 8 B/10 B encode& decode method to make the data rate reach 2.0 Gb/s, and make BER less than 10-12. Experimental result shows that it can solve no-matching data width problem, and realize parallel transmission for all data.
-
Computer Engineering. 2009, 35(11): 269-270,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.093In order to improve the research and application of traditional Chinese medicine, a software system is developed to mine the pharmacology from traditional Chinese medicine prescription. The system architecture, the designation of database and data preprocessing are described. Normalized data processing and statistical techniques are used in the system to mine the properties, flavors, channel from traditional Chinese medicine prescriptions. Dimensional vector technique combining the theory of traditional Chinese medicine is used to quantize and mine the information about effect and syndromes of a prescription.
-
Computer Engineering. 2009, 35(11): 271-273. https://doi.org/10.3969/j.issn.1000-3428.2009.11.094Linux is designed to be a general-purpose operating system, it is not suitable for real-time applications, but because of its open source, many solutions have been put forward to enhance its real-time ability. Inspired mostly by Gettimeofday(GTOD), the paper gives a method based on timer management improvement for high resolution timers. Experiments on the modified OS show that the improvement gives a better result for applications with real time constraints than original Linux kernel.
-
Computer Engineering. 2009, 35(11): 274-275,. https://doi.org/10.3969/j.issn.1000-3428.2009.11.095Computer modeling is an essential method in the process of metabolic network research. Aiming at disadvantages of current tools in analysis methods and model descriptions, this paper developes a visual metabolic modeling tool based on Cytoscape plug-in. One kind of general language is defined which can describe FBA and 13C-MFA metabolic models. Functions for metabolic network modeling under graphical user interface are implemented. The result of applications shows indicates that problems in current situation can be resolved well.
-
Computer Engineering. 2009, 35(11): 276-279. https://doi.org/10.3969/j.issn.1000-3428.2009.11.096To improve the real-time performance, it is necessary to develop data processing and display system. According to the characteristic of acquisition system of ATS-1 lidar, this paper designs a real-time processing and display system of lidar based on the multithread technique. The system can track the return signal data of lidar monitoring, process it automatically, displays the result in real time. It solves the problem that the original system has the shortage of existing long interval between data acquiring and data processing. This paper improves the real-time performance of lidar monitoring, ptoposes a kind of reference method for the design of real-time processing and display system of other lidars.
-
Computer Engineering. 2009, 35(11): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2009.11.097The memory management of μC/OS-Ⅱ adopts regional management algorithm, with high efficiency but for fixed memory block, it can not suit for the system with great changes of the size of memory block. This paper proposes a strategy of simplified adaptive dynamic memory allocation to improve the memory management of μC/OS-Ⅱ, makes it more suitable for the system with great changes of the size of memory block. Experimental results show that this method can meet the needs of the memory in embedded application.
-
Computer Engineering. 2009, 35(11): 283-封三. https://doi.org/10.3969/j.issn.1000-3428.2009.11.098The whole frame of regional coordination medical information system platform and the integrated techniques are researched. Data integration is conducted by using methods based on ontology from two aspects such as semanteme and structure. The data warehouse and virtual database are conbined to set up regional medical data center. The stability of the system is promoted by using hierarchical structure, which implements the Web Service integration of service-oriented hospital information system. Experimental results show this design scheme is effective and feasible.
2024
Volume 50 No 3
Volume 50 No 3
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428