Table of Content

01 November 2011, Volume 31 Issue 11

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Network and communications

Integrated routing strategy with high survivability for mobile Ad Hoc network

MA Chi MENG Jin ZHANG Hong

2011, 31(11):  2883-2886.  DOI: 10.3724/SP.J.1087.2011.02883

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Concerning that the performance of Mobile Ad Hoc NETwork (MANET) with normal route method degrades obviously when being under attack in battlefield, a new STHR route strategy which integrating AODV（MANET route method） and Spay & Waiter protocols（DTN route method）to achieve high survivability was proposed in this paper. And to reduce the total network load, the method for choosing DTN nodes was designed. At the situation of hard network attacking, the target node may not be searched by AODV search extending ring. Then the zone covering nodes called ZCSEN in this paper would be used to start DTN route progress. In this way, the performance of MANET becomes stable even when it is under attack. The experimental results by 'ONE' show that the delivery rate of STHR is better than AODV and the delay time is shorter than Spay & Waiter route protocol.

Energy-balanced routing algorithm for uneven distributed node wireless sensor network

HUANG Su-bin WANG Zhong-qun WANG Qian-song

2011, 31(11):  2887-2890.  DOI: 10.3724/SP.J.1087.2011.02887

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Concerning the unbalanced energy and "hotspot" energy hole problems caused by uneven distributed node in Wireless Sensor Network （WSN） clustering routing protocols, an energybalanced uneven distributed node routing protocol was proposed. In the routing protocol, the three parameters, i.e., the "degree" of the node, the distance of nodes to Sink, and the ratio between the average residual energy of clusters nodes and the node itself residual energy, were considered when primary(deputy)cluster head was chosen，and each cluster communicated with Sink through routing tree. The simulation results show that the new protocol can reduce the cluster head rotation frequency when cluster is in "hotspot" or clusters destiny is high, delay the first nodes death time, and make the energy consumption more balanced and the network life cycle longer.

ANT-LEACH: LEACH routing protocol integrated energy optimization by ant colony optimization in wireless sensor network

WANG Lin PAN Jun

2011, 31(11):  2891-2894.  DOI: 10.3724/SP.J.1087.2011.02891

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The classical routing protocol Low Energy Adaptive Clustering Hierarchy (LEACH) adopts adaptive clustering algorithm, and cluster heads communicate directly with base station. The longer the distance, the more energy will be consumed in the way of single-hop transmission. Eventually, the whole network will be out of work. An advanced routing protocol based on energy optimization named ANT-LEACH was proposed, which adopted the strategy of combining the Ant Colony Optimization algorithm with routing process of cluster head nodes. This protocol introduced lead force function to improve the ant transition probability and the pheromone updating rule. And it would take full account of the cluster head nodes' residual energy, make sure to find the optimal path between cluster heads and base station, and change the single-hop transmission to multi-hop. The simulation results demonstrate that this algorithm can effectively reduce nodes' energy consumption, prolong the lifetime of whole network and ensure load balance.

Selection and ordering of transmission-rate-aware candidate forwarders for opportunistic routing

CHEN Wei WEI Qiang ZHAO Yu-ting

2011, 31(11):  2895-2897.  DOI: 10.3724/SP.J.1087.2011.02895

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A transmission rate aware candidate forwarder selection and ordering algorithm based on expected transmission delay of nodes was proposed. It first separated opportunistic route forwarding into two components: the anycast forwarding from source node to its candidate forwarders set, and the remaining forwarding from that candidate forwarders set to destination, and then the shortest expected transmission delay of opportunistic routing was computed iteratively. Finally, candidate forwarders were selected and ordered according to the shortest expected transmission delay of nodes. The simulation results indicate that the proposed algorithm can improve the performance of opportunistic routing obviously.

Maximum lifetime routing based on ant colony in wireless sensor network

CHEN You-rong YU Li DONG Qi-fen HONG Zhen

2011, 31(11):  2898-2901.  DOI: 10.3724/SP.J.1087.2011.02898

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To prolong the lifetime in wireless sensor networks, the maximum lifetime routing based on ant colony algorithm (MLRAC) was proposed. This paper used the link energy consumption model and node transmission data probability to calculate the node total energy consumption in a data gathering cycle. Considering the node initial energy, MLRAC formulized the maximum lifetime routing into an optimal model. To solve the optimal model, the revised ant colony algorithm based on classical algorithm was proposed. It used new formulas for forwarding the probability of neighbor nodes and pheromone update, and a new method for packet detection. After some iterations of calculation, it could obtain the optimal network lifetime value and each node transmission data probability. Finally, sink node informed any other nodes in network with flooding. According to the received optimal probability, all nodes selected the neighbor node where the data packets did not pass to transmit data. The simulation results show that after a certain time of iteration, network lifetime of MLRAC reaches certain convergence. It can prolong network lifetime. Under certain conditions, MLRAC outperforms PEDAP-PA, LET, Sum-w and Ratio-w algorithms.

W-MAC: a MAC protocol with modified time division multiple access for

XIONG Peng

2011, 31(11):  2902-2904.  DOI: 10.3724/SP.J.1087.2011.02902

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Signal transmission conditions are very poor for ocean channel. It is a great challenge for Media Access Control (MAC) protocol to work reliably and effectively in Underwater Acoustic Sensor Networks (UASN). Due to the long and changeful propagation delay, a new MAC with modified TDMA named W-MAC was proposed, which could adapt underwater environment through simplified synchronization process, the defer time to allocate transmitting of all nodes as well as the detection time with sleep scheme to prevent from data collision to decrease the overhead of energy. The simulation results show W-MAC is quite efficient when data traffic is high in underwater acoustic sensor network.

Improved active queue management algorithm for fairness of CHOKe

TIAN Shuo GAO Zhong-he

2011, 31(11):  2905-2908.  DOI: 10.3724/SP.J.1087.2011.02905

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Active Queue Management plays an important role in the congestion control of network. In order to solve the problem that CHOKe algorithm cannot punish the non-responsive flows enough and the low accuracy, a new algorithm, LRU-CHOKe to penalize for non-responsive flows, was proposed in the paper. The algorithm did not only replace the CHOKe hit with LRU hit to improve the effectiveness of CHOKe hit, but also used queue hit to adaptively determine the number of packet loss. A new way of dropping packets to punish non-responsive flows was adopted. The simulation results show that LRU-CHOKe performs better than CHOKe in punishing non-responsive flows. As a result, the bandwidth allocation is realized more fairly.

Price-based spectrum sharing model in cognitive radio networks

YANG Hui-hui QIU Jing

2011, 31(11):  2909-2911.  DOI: 10.3724/SP.J.1087.2011.02909

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To dynamically adjust the bandwidth price according to the change of channel quality so as to change the users' profit, an improved spectrum sharing model considering user's mobility was proposed．The improved model comprehensively considers the impact on the price of the offered bands by all secondary users' bandwidth requirement and channel quality; at the same time, the requested bandwidth gets constrained by price, and thus users' profit change with position. The simulation results indicate that users can gain maximum profit by choosing a optimal position in the moving process.

The spectral efficiency performance analysis of the closed-loop scheduling algorithm in multi-user MIMO system

GUO Lili WANG Yang

2011, 31(11):  2912-2914.  DOI: 10.3724/SP.J.1087.2011.02912

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A closed-loop scheduling algorithm was proposed for multi-user Multi-Input Multi-Output (MIMO) system to improve wireless spectral performance. Using greedy scheduling technology from multi-user diversity, the algorithm combined the adaptive modulation in the physical layer with automatic repetitive request in the data link layer, and the system's spectral efficiency was enhanced under the interaction of the multi-antenna diversity and multi-user diversity. Considering the practical case of delayed feedback environment, the closed-form expressions of system spectral efficiency under delayed channel were derived. And the experimental results show that this algorithm can hardly be influenced by delay time, which is more applicable to multi-user MIMO system.

New adaptive dynamic channel allocation algorithm in cognitive Radio

LONG Yin YIN Heng-jing ZHU Jiang LI Fang-wei

2011, 31(11):  2915-2917.  DOI: 10.3724/SP.J.1087.2011.02915

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According to the characteristics of primary users’ service, this paper applied mixed Poisson distribution to primary users’ service modeling, evaluating the probability density of non-occupied duration of channel by using Expectation-Maximization (EM) algorithm to estimate the parameters of mixed Poisson distribution model and putting forward a multi-channel allocation algorithm based on channel estimation. The simulation results indicate that the proposed algorithm has excellent performance on conflict rate and throughput. Meanwhile, the proposed algorithm has lower implementation complexity for practical use.

Power line carrier communications timing synchronization and FPGA implementation

2011, 31(11):  2918-2921.  DOI: 10.3724/SP.J.1087.2011.02918

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Large power line noise results in false frame synchronization and such problems as the peak amplitude in symbol timing synchronization changes with the attenuate signal and peak sidelobe exceeds the threshold. Therefore, based on the PLC G3 physical layer specification, this paper elaborated an improved frame synchronization and symbol timing synchronization algorithm with higher accuracy and less hardware resources occupancy. Through the simulation, the new algorithm shows adaptive threshold and better performance in conquering the interference of side lobe at low Signal-to-Noise (SNR). And it is easier to design in hardware. In the end, in two development tools of which one sends out signal and the other receives signal validate even when there is a large power line noise, the method can still achieve accurate real-time, continuous timing synchronization on the power line carrier communication baseband system.

Signal noise separation algorithm based on morphology gradient

YAN Tian-feng MA Rui

2011, 31(11):  2922-2925.  DOI: 10.3724/SP.J.1087.2011.02922

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In automatic measurement of the radio spectrum parameters, the traditional threshold-based method is difficult to obtain satisfactory result when the spectrum has undulating background noise. To solve this problem, this paper proposed a signal noise separation algorithm based on morphological gradient to separate signals from background noise by detecting edges of signals. The experimental results show that this algorithm can deal with the spectrum with undulating background noise, and get more accurate separation result than the traditional method.

Recognition algorithm of digital modulation based on wavelet and high-order cumulants

LI Shi-ping CHEN Fang-chao

2011, 31(11):  2926-2928.  DOI: 10.3724/SP.J.1087.2011.02926

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When using recognition algorithm of high-order cumulants to classify and recognize digital modulation signals, the calculation of six-order and six-order above cumulants are too complex and the signals of 8PSK and Multiple Frequency Shift Keying (MFSK) have the same cumulants, so it is impossible to recognize directly. To solve this problem, a new classification algorithm was proposed in this paper, which made wavelet transform on MFSK and 8PSK at first, and then used four-order cumulants recognition. The simulations show that the characteristic parameters could restrain Gaussian white noise efficiently and simply, and classify and recognize 2ASK/BPSK, 4ASK, 2FSK, 4FSK, QPSK, 8PSK and 16QAM successfully. When SNR (Signal-to-Noise Ratio) is 3dB, the recognition rate reaches as high as 96%. Compared with the existing algorithms, the superiority of the algorithm is proved.

Computer software technology

Region coupling cellular automaton model with probability state transformation

HUANG Guang-qiu SHEN Xiao-gang

2011, 31(11):  2929-2935.  DOI: 10.3724/SP.J.1087.2011.02929

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Concerning the local features of sub-regions in large-scale irregular multi-region system, a region coupling Cellular Automaton (CA) model with probability state transformation was proposed. In this model, the principles of region coupling and rules of information exchange were used to construct evolution rules, and different sub-regions were constructed respectively by different CA models with the probabilistic method to deal with the state transformation. A simulation experiment shows that each local region can keep its relative independence of itself evolution while its cells can keep the special order status with cells in the coupled border part, and the effect of a sub-region can transfer into other sub-regions. The model can be used to deal with the simulation of space evolution of large-scale irregular regions.

Power-aware algorithm for hard real-time tasks scheduling in multi-core embedded environment

JING Si-yuan SHE Kun ZHONG Yi

2011, 31(11):  2936-2939.  DOI: 10.3724/SP.J.1087.2011.02936

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Taking full consideration of that CMOS multi-core embedded processor only provides global Dynamic Voltage Scaling (DVS) and its power leakage is serious, this paper proposed a new power-aware scheduling algorithm GRR&CS for hard real-time tasks in multi-core embedded environment. The power saving was achieved by three steps, including greedy-based static tasks partition, global resource reclamation based dynamic load balance and dynamic core scaling. The algorithm also keeps the schedulability of tasks. The experimental results show that the proposed algorithm saves more about 14.8%-41.2% energy than other existing works.

Erasure Code algorithm based on distributed server in cloud storage environment

GE Jun-wei LI Zhi-qiang FANG Yi-qiu

2011, 31(11):  2940-2942.  DOI: 10.3724/SP.J.1087.2011.02940

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The main weak point of Erasure Code algorithm based on the single server scenario is that the system efficiency is low when lots of users access system. This paper proposed decentralized Erasure Code to solve the problem. Redundant storage was achieved by the partition and encoding of the original data. The experimental results show that this algorithm can ensure data reliability and confidentiality in the Cloud storage environment. It can also avoid the load overweight of the single server and improve the throughput and resource utilization of the system.

Survey on FPGA-based regular expressions matching algorithms

TANG Qiu JIANG Lei TAN Jian-long LIU Jin-gang

2011, 31(11):  2943-2946.  DOI: 10.3724/SP.J.1087.2011.02943

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The advantages of hardware-based regular expressions matching were analyzed. At the same time, the basic ideas and methodology for Field Programmable Gate Array (FPGA)-based regular expressions matching were introduced. Furthermore, an algorithm classification approach was proposed in terms of two technical indicators: matching speed and resource utilization. The advantages, disadvantages and the basic ideas of various algorithms were summarized. Finally, the key techniques, difficulties and the future direction in this field were discussed.

Device description schema of XML combined with function block

MA Zhen-fang FENG Dong-qin

2011, 31(11):  2947-2949.  DOI: 10.3724/SP.J.1087.2011.02947

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The existing device description methods are not general but complex. Extensible Device Description Language (DDL) of XML-based was researched and Ethernet for Plant Automation (EPA) function blocks were applied in EPA device description language. According to the function block structure, the property of EPA equipments from different manufacturers was divided into several major categories, so the description of simulation function blocks could correspond with the description of equipment function blocks. This method was applied to the EPAConfiguration software. The comprehensive description of function block and device description was achieved, which can make the management and control of field devices easier.

Information security

Authentication scheme for trusted mobile nodes in wireless network

SUN Li-na CHANG Gui-ran WANG Xing-wei

2011, 31(11):  2950-2953.  DOI: 10.3724/SP.J.1087.2011.02950

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The platform authentication protocol based on the property without the third party and the encryption protocol based on identity were applied to the node authentication scheme under the wireless networks. Compared with the existing methods, the proposed trusted mobile node access scheme has two major features: 1) both the mobile platform identity and the mobile user identity are verified at the same time; 2) the mutual attestation not only between the mobile user and the network Agent, but also between the mobile users are provided. Analysis shows that the improved scheme can meet the anonymous requirement.

Identity-based improvement of wireless transport layer security handshake protocol

CHEN Shuang-shuang CHEN Ze-mao WANG Hao

2011, 31(11):  2954-2956.  DOI: 10.3724/SP.J.1087.2011.02954

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The Wireless Transport Layer Security (WTLS) handshake protocol was built based on digital certificate mechanism. However, there exist several flaws in WTLS. For example, both the communication and computation overload are high. Moreover, it does not verify the server certificate on-line. In order to solve these issues, an improved WTLS handshake protocol based on Identity-based Cryptosystem (IBC) was proposed. It is constructed based on ID, and IDs are exchanged between server and client instead of certificates. Identity-based Encryption (IBE), Identity-based Signature (IBS) and Identity-based Authenticated Key Agreement (IBAKA) were adopted to implement security functions of encryption, signature and key agreement respectively. Sender's ID information was embedded into encryption key computation, which can be used to authenticate the source of message. The analysis on security and efficiency shows that the efficiency of wireless communication is improved without security loss.

Modeling and analysis of discrete-time hybrid-benign worms

LIN Jin-xian LIN Jun-qing

2011, 31(11):  2957-2960.  DOI: 10.3724/SP.J.1087.2011.02957

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In order to better characterize the propagation of benign worm, this paper adopted a discrete-time model. Under discrete time, the paper analyzed the propagation of hybrid-benign worms and presented a mathematical modeling, which took account of the network influence due to the spread of malicious worms and benign worms. Finally, the simulation validated the propagation model, and the key parameters were compared and analyzed with Taylor Equation. The theoretical analysis and experimental results indicate that there exists a critical value of switch time under a defined release time of hybrid-benign worms and the certain performance of network. And when the sensitivity of the network is small enough, different switch time would have no influence on the movement of the number of the infected hosts.

New method of pattern-matching for network intrusion detection

FAN Ai-jing YANG Zhao-feng

2011, 31(11):  2961-2964.  DOI: 10.3724/SP.J.1087.2011.02961

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New generations of Network Intrusion Detection Systems (NIDS) create the need for advanced pattern-matching engines. This paper presented a new scheme for pattern-matching, which adopted a hardware-based programmable state machine technology to achieve deterministic processing rates. A lot of patterns can be obtained in one input stream by Balanced Routing Table-based FSM (B-FSM), and transition rules can be mapped effectively. Experiments had been done with Snort used widely in network intrusion detection systems. The experimental results show that the method is effective in storage, fast in operation, and renewable dynamically. The method proposed in this paper can satisfy the requirement of NIDS.

P2P identification method based on flow identification

JIAO Cheng-bo

2011, 31(11):  2965-2968.  DOI: 10.3724/SP.J.1087.2011.02965

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Mixed flows retransmitted by Network Address Translator (NAT) are similar to Peer-to-Peer (P2P) flows in terms of traffic characteristics. The measurement result shows that without flow identification the TLI method will have high false positives and false negatives. In order to solve this problem, a new P2P traffic identification method based on flow classification was proposed. Firstly, flow classification was done by analyzing IP identification time series. Based on classification results, P2P traffic was identified by checking its traffic characteristics. The proposed method was put to test through popular P2P application. The result shows that it can reduce the false positives and false negatives widely, so new P2P traffic classification method has better application value.

Attribute-based encryption scheme with hidden access policy

CHEN Qin MA Dan-dan ZHANG Jin-man DANG Zheng-qin

2011, 31(11):  2969-2972.  DOI: 10.3724/SP.J.1087.2011.02969

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In most attribute-based encryption schemes, access policy, which is used to encrypt message by encryptor, is often sent to the decryptor along with the ciphertext, but sometimes the policy itself is sensitive. This paper proposed a new construction to hide the access policy. During the encryption process, encryptor achieve the indistinguishability between the well-formed ciphertext components and the malformed. Compared with other constructions, ours was more efficient by reducing the times of exponent and pairing, and the sizes of ciphertext and keys were smaller. In addition, new attributes could be added in the ciphertext policy after setup was executed and the existing public parameters can remain unchanged. These analyses show the flexibility of construction. Security gets proved based on decisional bilinear Diffie-Hellman assumption.

Resisting power analysis attack scheme based on signed double-based number system

WANG Zheng-yi ZHAO Jun-ge

2011, 31(11):  2973-2974.  DOI: 10.3724/SP.J.1087.2011.02973

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Due to the limited resource of security chip, the scheme resisting power analysis attack was researched from two aspects of operation efficiency and withstanding multiple power analysis attacks. A scheme based on Signed Double-based Number System (SDBNS) was presented by coding the key renewably and basic point masking algorithm. According to security analysis, the result shows that the scheme could resist multiple power analysis attacks and promote operation efficiency.

Malware analysis method based on reverse technology

LUO Wen-hua

2011, 31(11):  2975-2978.  DOI: 10.3724/SP.J.1087.2011.02975

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Reverse analysis is the most common method in analyzing malware. The reverse analysis process is an advanced and efficient method that exposes the intention and processes of malware. The focus of this paper was to show the general patterns ascertained using reverse analysis applied to the aspects of start function, parameter transfer of function, data structure, control statement and Windows API. A case study of malware, used to obtain account information, login names, and passwords for the popular Chinese social networking program "QQ", was presented to illustrate how the reverse analysis quickly and accurately locates key information used to determine general patterns.

Proxy signature scheme based on braid group

ZUO Li-ming TANG Peng-zhi LIU Er-gen

2011, 31(11):  2979-2982.  DOI: 10.3724/SP.J.1087.2011.02979

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The braid group is a new candidate platform for constructing quantum attack-resistant public key encryption system. The proxy signature allows a proxy signer to sign messages on behalf of an original signer who delegates his signing power to the proxy signer. A proxy signature based on root finding problem over braid group was put forward, the analysis of its correctness, security, efficiency and parameter choice were subsequently presented, and afterwards the detailed formal security proofs in the Random Oracle Model (ROM) were given. The new scheme can resist current known attacks.

Cryptanalysis and improvement of an online/offline signcryption scheme

LI Zhi-min XU Xin LI Cun-hua

2011, 31(11):  2983-2985.  DOI: 10.3724/SP.J.1087.2011.02983

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Liu's online/offline signcryption scheme (LIU J K, BAEK J, ZHOU J. Online/offline identity-based signcryption re-visited. Inscrypt'10: Proceedings of the 6th International Conference on Information Security and Cryptology. Berlin: Springer-Verlag, 2010:90-102) was cryptanalyzed and improved in this paper. By studying the unforgeability of Liu's scheme, this paper proved that Liu's scheme would be not unforgeable against adaptive chosen message and identity attack. To overcome the security problem in Liu's scheme, a modified scheme was proposed, and the modified scheme was proved to be a secure Identity-based online/offline signcryption scheme.

New identity-based proxy re-signcryption

WANG Hui-ge WANG Cai-fen CAO Hao LIU Shao-hui

2011, 31(11):  2986-2989.  DOI: 10.3724/SP.J.1087.2011.02986

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A new identity-based proxy re-signcryption scheme was put forward on the basis of the signcryption with proxy re-encryption proposed by Chandrasekar S (CHANDRASEKAR S, AMBIKA K, RANGAN P C. Signcryption with proxy re-encryption . http://eprint.iacr.org/2008/276). The new scheme achieves a transparent conversion from one identity-based signcryption to another identity-based signcryption by using a semi-trusted proxy. And it realizes the complete conversion of signcryption, that is, it concurrently achieves the conversion of both confidentiality and verification. In the same time, it realizes the full public verifiability of the signcryption without the direct participation of the plaintext. Based on the Computation Bilinear Diffie-Hellman (CBDH) problem, it is proved to be IND-CCA2 secure in the Random Oracle Model (ROM). Through the analysis of its efficiency and function, the scheme resolves the problems of both failing to realize the conversion of the verification and the verifiability of signcryption needing the participation of plaintext in the scheme advanced by Chandrasekar S.

Certificateless partially blind signature without pairing

XUE Bing JING Wei-na

2011, 31(11):  2990-2993.  DOI: 10.3724/SP.J.1087.2011.02990

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Because of the large amount of calculation for pairing, a partially blind signature scheme without pairing was proposed, which combined the new certificateless public key cryptosystem. The security of the new scheme was analyzed with the random oracle model. The results show that the new scheme satisfies the unforgeability and the partial blindness. On the basis of the Discrete Logarithm Problem (DLP) and CDH (Computational Diffie-Hellman) assumption, the computational ability of the new scheme is better than other certificateless ones, and it can be applied to construct secure mobile e-commerce.

Analysis and improvement on a new three-party password-based authenticated key agreement protocol

ZHOU Si-fang

2011, 31(11):  2994-2996.  DOI: 10.3724/SP.J.1087.2011.02994

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In 2010, Z. Mohammad proposed a new two-party authenticated key agreement protocol (MOHAMMAD Z, CHEN Y, HSU C, et al. Cryptanalysis and enhancement of two-pass authenticated key agreement with key confirmation protocols. IETE Technical Review, 2010,27(3):252-65). This protocol realizes the key agreement with higher computation efficiency. However, the one-round version of this protocol cannot resist on the loss of information impersonation attack, key compromise impersonation attack and general impersonation attack, this protocol is also vulnerable to man-in-the-middle attack if some security information is lost. These security problems allow the adversary can initiate or reply the protocol with legal participants.

Graphics and image technology

Fast video transcoding algorithm based on hybrid characteristic of multi-scale videos

LU Zhuo-yi JIA Ke-bin XIAO Yun-zhi

2011, 31(11):  2997-3000.  DOI: 10.3724/SP.J.1087.2011.02997

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A fast intra mode decision scheme for down-sizing video transcoding in H.264 based on hybrid characteristic of multi-scale videos was presented. In order to reduce the high computational complexity of using conventional intra prediction in the H.264 re-encoder, the proposed scheme firstly utilized 2D-histogram to extract the spatial characteristic of macro-blocks in the low-resolution video to choose from intra 16×16 and intra 4×4. Then the Support Vector Machine (SVM) was used to exploit the correlation between coding information extracted from the input high-resolution bit-stream and the coding modes of macro-blocks in down-sized video frames. With the SVM classifier, the improbable modes in the nine intra 4×4 modes were eliminated and only a small number of candidate modes were carried out using the RDO operations. Hence, remarkable computation time can be saved, while maintaining nearly the same quality of the transcoded pictures.

Improved rate control algorithm of basic unit layer in H.264

SHI Chun-ming HUANG Dong-jun

2011, 31(11):  3001-3003.  DOI: 10.3724/SP.J.1087.2011.03001

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In the standard H.264 algorithm, only time relevance is used while predicting the Mean Absolute Difference (MAD). Therefore, an improved rate control algorithm of basic unit layer was introduced combining the time prediction and space prediction, while taking advantage of the change tendency of MAD. When compared with the standard rate control algorithm, adopted by the JVT H.264 reference software JM8.6, the proposed rate control algorithm can not only reduce the mismatch between actual bit rates and target ones, but also increase the average luminance Peak Signal-to-Noise (PSNR) of reconstructed video.

Remote sensing image segmentation using possibilistic fuzzy c-means clustering algorithm based on spatial-information

ZHANG Yi-hang WANG Xia FANG Shi-ming LI Xiao-dong LING Feng

2011, 31(11):  3004-3007.  DOI: 10.3724/SP.J.1087.2011.03004

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Fuzzy C-Means (FCM) clustering algorithm is very sensitive to image noise when it is used to image segmentation. As an improvement of FCM, Possibility FCM (PFCM) clustering algorithm can reduce the influence of image noise on image segmentation to some extent. However, since no spatial information of the image is taken into consideration, PFCM can not perform well when the image contains much noise. In order to further improve the segmentation accuracy of PFCM when much noise is present in the image, a new Spatial PFCM (SPFCM) algorithm was proposed by incorporating the spatial information of each pixel into the traditional PFCM algorithm in this paper. Both synthetic and IKONOS images with different kinds of noise were applied, and the segmentation results show that the proposed SPFCM clustering prevails over the FCM, PFCM, FCM-S1 and FCM-S2 visually and quantitatively. When dealing with different image noise, its average segmentation rate is as high as 99.71%, which shows the effectiveness of the proposed algorithm.

Automatic focusing algorithm based on improved gray contrast function

HUANG Wei-qiong YOU Lin-ru LIU Shao-jun

2011, 31(11):  3008-3009.  DOI: 10.3724/SP.J.1087.2011.03008

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To meet the fast and accurate requirement of image measurement in the auto-focusing system of image measurement instrument, gray contrast function was improved as following: by making use of the features that the focus image has smaller range of the gray scale transition than the defocused image and calculating the average change in gray value, focusing was reached with the number of changes in gray-scale. The comparison shows that the improved gray scale contrast function has simpler time computational complexity and higher focusing sensitivity. The improved function, with good stability, has faster focusing speed and higher focusing accuracy than other methods in the auto-focusing system of image measurement instrument.

New camera self-calibration method based on image sequences

WU Qing-shuang FU Zhong-liang MENG Qing-xiang

2011, 31(11):  3010-3014.  DOI: 10.3724/SP.J.1087.2011.03010

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This paper proposed a new camera self-calibration method based on image sequences, which combined the theory of photogrammetry and computer vision. Firstly, the camera foundation matrix F was obtained by making use of the 8 points algorithm according to the image matching points, and the matrix C was got based on utilizing Kruppa equation and the foundation matrix F, then the matrix C was decomposed with Cholesky method to get the camera internal parameter matrix K. Secondly, the relative orientation and absolute orientation were carried on taking the internal parameters as the initial value, then the image matching points's 3d space coordinate was got by least squares forward intersection. Finally, the accurate camera internal parameters, external parameters and distortion coefficients were calculated by three-dimensional direct linear transformation and bundle adjustment methods. This self-calibration method does not depend on the particular geometric constraints in the scene, and it can be carried out as long as there are matching points, so it has broad applicability. Both simulation data and real images were used to test the method, and the results show that: this new method gets high precision and low computational complexity; it is a new and valid method for camera self-calibration.

Image denoising based on image transformation coefficient sparsity

LI Rui HE Kun ZHOU Ji-liu

2011, 31(11):  3015-3017.  DOI: 10.3724/SP.J.1087.2011.03015

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This paper proposed an image denoising method using transform-domain sparse representation with the characteristic that fewer Discrete Cosine Transformation (DCT) nonzero coefficients exist in image smoothing-domain. This method overcame the shortcoming of traditional denoising method, i.e. losing information of edge and texture. Firstly, similar image block was grouped by computing l2 norm; secondly, according to transform-domain coefficient sparsity, denoising was performed by threshold. To improve it, Principal Component Analysis (PCA) was used on these groups, processing groups with PC components. Lastly, the image with processed groups was reconstructed using Kaiser windows method. Compared to traditional method, this method preserves image edge and texture information, so that the noise could be preferably removed and the effect of image visual could be improved.

Edge detection algorithm based on recursive filtering

XUE Si-zhong

2011, 31(11):  3018-3021.  DOI: 10.3724/SP.J.1087.2011.03018

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For the edges detection problem of digital images containing different degrees of noise, two smoothing and edge detection filters, based on a model of crest-line blurred edge contours, were proposed. First, these filters were used to achieve image smoothing and gradient calculation by the third-order recursive form, and then non-maximum suppression and dual-threshold edge detection were performed. The experimental results show that the proposed method can obtain more clear gradient images, accurate detected edge and less computational time than the ones with Canny and Deriche operators.

Objective quality evaluation of image fusion based on visual attention mechanism and regional structural similarity

REN Xian-yi LIU Xiu-jian HU Tao ZHANG Ji-hong

2011, 31(11):  3022-3026.  DOI: 10.3724/SP.J.1087.2011.03022

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To handle the problem of low consistency between the objective and subjective evaluations of image fusion, considering the features of Human Visual System (HVS), a new metric to evaluate the quality of the fusion image based on the Visual Attention Mechanism (VAM) and the regional structural similarity was proposed. This quality metric utilized the global salience got by VAM and the local salient information to estimate how well the salient information contained within the sources was presented by the composite image. Since human eyes are more sensitive to region, by giving higher weight to those regions with high saliency value in the source images, the new metric evaluated the quality of the fused image by computing the weighted regional structural similarity of the fused image and source images in all regions. The correlation analysis between objective measure and subjective evaluation was performed and the results demonstrate that the new metric is more consistent with human subjective evaluation, compared with the traditional objective measurements and the widely used EFQI.

Measurement of surface area and lumen volume of industrial computed tomography three-dimensional images

2011, 31(11):  3027-3030.  DOI: 10.3724/SP.J.1087.2011.03027

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The measurement of the size parameters of three-dimensional products is the base of gaining the design drawings from the products in reverse engineering. However, the measurement of the internal structure in products is difficult to achieve, especially the closed lumen by traditional measurement methods. A measurement method which is about surface area and lumen volume of industrial Computed Tomography (CT) three-dimensional images was studied, the C-V method was used to segment the industrial CT images, and area and volume were calculated based on getting the contour points of target area. In order to get smooth surface, the distance data between points on the surface and the center point was calculated, then Gaussian filter was used to remeasure the contour filter. The experimental results show that the method has better precision compared to the traditional measurement methods.

Bump feature extraction based on attributed adjacency graph in reverse engineering

SONG Liang-hao LIU Guang-shuai LI Bai-lin ZHANG Li

2011, 31(11):  3031-3034.  DOI: 10.3724/SP.J.1087.2011.03031

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Combined feature extraction in Reverse Engineering (RE) is beneficial to improving the whole quality of reconstruction model and reflecting the original design intention, but currently reletated research is not intensive. In order to extract bump feature which belongs to a simple combined feature from point cloud data in reverse engineering, a method based on Attribute Adjacency Graph (AAG) for extraction bump feature was proposed. Firstly, the algorithm based on AAG decomposition was used to recognize stock feature. Then, the parameters of stock feature were extracted and the type of stock feature was distinguished. The experimental results show that the method is effective and direct to extract different types of stock features.

Visualization of human meridian based on graphic transformation

LI Peng-feng CHEN Xin

2011, 31(11):  3035-3037.  DOI: 10.3724/SP.J.1087.2011.03035

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This paper proposed a method for locating and displaying the human meridian directly in real-time. Firstly, a multi-channel meridian impedance detector and a magnetic orientation tracker were introduced in this paper to locate the position of meridian to gain the 3-Dimensional (3D) information of meridian. Secondly, camera calibration was done for the scene camera, and then its result and the meridian points' 3D information were transformed to the same world coordinate system according to their space relative position, so that the projection matrix of camera H was obtained. Finally, using this matrix H, the 3D data of meridian points was projected onto image to form the 2-Dimensional (2D) meridian line which was matched and fused with human body image captured by the camera to visualize the human meridian. The result shows that the method can locate and display the human meridian precisely and efficiently on the actual human body image in real-time.

Feature selection in word spotting technology for retrieving historical Mongolian document images

WEI Hong-xi GAO Guang-lai

2011, 31(11):  3038-3041.  DOI: 10.3724/SP.J.1087.2011.03038

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A systematic frame for retrieving Mongolian Kanjur images by word spotting technology was designed. Some features including profile feature, projection feature and back-to-ink transition were adopted to represent Mongolian word images by deeply analyzing characteristics of handwritten Mongolian word images. By doing a lot of comparison experiments on the dataset with 5500 word images, the best combination of features was determined. Meanwhile, the Mean Average Precision (MAP) of about 78.79% was achieved and the R-Precision 73.01%. The experimental results show that the selective features are valid and effective.

Adaptive switching algorithm for complicated motion video target tracking

DAI Wan-chang

2011, 31(11):  3042-3044.  DOI: 10.3724/SP.J.1087.2011.03042

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Concerning the uncertainty of video target state transition model and random noise distribution in actual environment, an algorithm used for video target tracking in complicated movement was proposed. The algorithm adopted the advantage of Kalman Filter (KF) which was of excellent real-time quality, and the advantage of Partical Filter (PF) which could deal with non-linear and non-Gaussian filtering at the same time. By analyzing the performance of KF and making its performance parameters as a determinstic term, KF and PF could be switched adaptively. By means of test, it is suggested that the method proposed in this paper can carry out steady tracking when the target motion state changes significantly, with high tracking accuracy.

Image classification method based on hierarchy semantics

KONG Ying-hui SU Liang

2011, 31(11):  3045-3047.  DOI: 10.3724/SP.J.1087.2011.03045

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In order to better achieve the image retrieval based on semantics, the integrated features of color, texture and shape were used to represent the image and were also regarded as input vectors of Support Vector Machine (SVM). Through making study of image classes, the correlation from image low-level features to high-level semantics was built. The classification accuracy was improved by using comprehensive features. Then image library was organized by the semantic structure, and hierarchical representation of image semantics was realized. All keywords of different levels were combined to describe the semantic of images. The results show that the proposed method can make the image expressed by more comprehensive semantic in the case of getting good classification accuracy.

Novel Image Digital Watermark Algorithm with Weighted fractional calculus based on Wavelet Coefficients

LIU Lei MIAO Qiguang SHI Cheng

2011, 31(11):  3048-3052.  DOI: 10.3724/SP.J.1087.2011.03048

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In this paper, a novel digital watermark algorithm, based on fractional calculus and wavelet transform, for still images is proposed. It makes fully use of the characteristic of the fractional order that is highly sensitive. The algorithm makes sinusoidal signal by fractional Cauchy formula with two differential orders. The sampled signals of the differential signals were superimposed as the pseudo-random sequence which is used to scramble the watermark. By exchanging the high-frequency coefficients of the carrier image, the scrambled watermark was embedded into the carrier image. Several experiments to verify the proposed method are given and the results show that this novel algorithm is robust to a number of regular geometric attacks and other image processing operations. The new method has a good performance on both robustness and invisibility.

Novel image blocking Encryption algorithm based on spatiotemporal chaos system

ZHENG Hong-ying LI Wen-jie XIAO Di

2011, 31(11):  3053-3055.  DOI: 10.3724/SP.J.1087.2011.03053

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In this paper, a novel image blocks encryption algorithm based on Coupled Map Lattice (CML) system was presented to solve the parallel problem of the common image encryption algorithm. The basic idea is to divide the image into blocks，and then used the block number as the spatial parameter of CML to iterate the chaos system. The chaotic stream was used to conduct confusion operations with part of the image，the result of which was applied to encrypt the other part. The proposed method can encrypt image in parallel and can also satisfy color image encryption. The simulation process indicates that the algorithm is easy to realize with low computation complexity，high sensitivity，high speed，high security and other properties simultaneously.

Color image watermarking based on human visual system and discrete wavelet transform

ZHANG Liang-liang CHEN Xiu-hong

2011, 31(11):  3056-3059.  DOI: 10.3724/SP.J.1087.2011.03056

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In order to extend the range of applying of digital watermarks,this paper introduced a watermarking algorithm for color image based on Human Visual System (HVS) and Discrete Wavelet Transform (DWT). First, a meaningful binary image was encrypted by chaotic encryption algorithm to form watermark. Then the color image was converted from RGB color space to YCbCr space; the Y component was extracted and one level discrete wavelet transform was executed. Finally, the visual masking value of LL1 was got. According to the visual masking value, the watermark was embedded into the low-frequency wavelet coefficient domains of Y components of color image. Experimental results show that the proposed algorithm has better invisibility and robustness than the algorithm based on YCbCr color space.

Database technology

Improved collaborative filtering algorithm based on symbolic data analysis

GUO Jun-peng CHEN Ying-ying

2011, 31(11):  3060-3062.  DOI: 10.3724/SP.J.1087.2011.03060

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With the continuing increase of users and kinds of resources, the problem of rating matrix's sparsity is becoming more and more prominent, which seriously affects the quality of the recommendation system. Singular Value Decomposition (SVD) is a dimension reduction method, and Symbolic Data Analysis (SDA) is a new analytical approach to processing mass data. This paper proposed a new collaborative filtering recommendation algorithm which combines SVD with SDA. The experimental results based on EachMovie database set indicate that the proposed method is significantly better than traditional general recommendation algorithm when the data is particularly sparse.

Nonlinear combinatorial collaborative filtering recommendation algorithm

LI Guo ZHANG Zhi-bin LIU Fang-xian JIANG Bo YAO Wen-wei

2011, 31(11):  3063-3067.  DOI: 10.3724/SP.J.1087.2011.03063

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Collaborative filtering is the most popular personalized recommendation technology at present. However, the existing algorithms are limited to the user-item rating matrix, which suffers from sparsity and cold-start problems. Neighbours' similarity only considers the items which users evaluate together, but ignores the correlation of item attribute and user characteristic. In addition, the traditional ones have taken users' interests in different time into equal consideration. As a result, they lack real-time nature. Concerning the above problems, this paper proposed a nonlinear combinatorial collaborative filtering algorithm consequently. In order to obtain more accurate nearest neighbour sets, it improved neighbours' similarity calculated approach based on item attribute and user characteristic respectively. Furthermore, the initial prediction rating fills in the rating matrix, so makes it much denser. Lastly, it added time weight to the final prediction rating, so then let users' latest interests take the biggest weight. The experimental results show that the optimized algorithm can increase prediction precision, by way of reducing sparsity and cold-start problems, and realizing real-time recommendation effectively.

Active measurement of PPStream VOD system and client behavior analysis

HAO Zheng-hong CHEN Xing-shu WANG Hai-zhou HU Xin

2011, 31(11):  3068-3071.  DOI: 10.3724/SP.J.1087.2011.03068

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The analysis results on PPStream-VOD System client behavior characteristics were presented in this paper. This study began from researching on peer-distributing protocol and the architecture of Buffer-Map based on passive measurement. A dedicated PPS-VOD crawler was deployed to capture clients’ Buffer-Map and study the characteristics of client watching behavior. By accurate data analysis, the client behavior was classified as Long-Smoother, Short-Smoother and Jumper. Then the proportion of three kinds of clients and their different watching behaviors were proposed. The concept watching viscosity was put forward to reveal the attraction of program to users, which is in direct proportion to average watching time, and in inverse proportion to slope of probabillty accumulation curve.

Naive Bayesian classification algorithm based on attribute clustering under different classification

PENG Xing-yuan LIU Qiong-sun

2011, 31(11):  3072-3074.  DOI: 10.3724/SP.J.1087.2011.03072

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In numerous classification methods, although Naive Bayesian (NB) classification algorithm is simple and effective, its attribute independence assumption ignores the correlation among attributes. To consider the influence of the attribute independence assumption, a new grouping technology which clusters the conditional attributes was proposed. This technology not only overcomes the deficiency arising from the attribute independence assumption of the traditional NB classification algorithm, but also reflects the different correlation intensity among attributes when the classification is different. Simulation results on a variety of UCI data sets illustrate the efficiency of this method.

Improved word similarity algorithm based on HowNet

WANG Xiao-lin WANG Yi

2011, 31(11):  3075-3077.  DOI: 10.3724/SP.J.1087.2011.03075

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The word similarity computation is widely used in text classification, question-answer system, machine-translation and text clustering. Research of this computation is generally based on HowNet, according to the distance and the depth of sememes. Based on above, an improved method of word similarity computation was proposed as follows. Firstly, a new variable coefficient of homonym similarity computing was proposed according to the count of homonym. Secondly, it took part of speech into account and argued that the part of speech of homonym is different in contributions to word similarity and removed the combinations of homonyms with different part of speech. The experimental results show that the result obtained through this newly-improved computation method is better with less complex calculation and higher calculation efficiency.

Snapshot K neighbor query processing on moving objects in road networks

LU Bing-liang LIU Na

2011, 31(11):  3078-3083.  DOI: 10.3724/SP.J.1087.2011.03078

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The functionality of a framework that supported location-based services on moving objects in road networks was extended and Snapshot K Nearest Neighbor (SKNN) queries based on Mobile Network Distance Range (MNDR) queries was proposed using an on-disk R-tree to store the network connectivity and an in-memory grid structure to maintain the moving object position updates. The minimum and maximum number of grid cells of a given arbitrary edge in the space that were possibly affected were analyzed. The maximum bound that could be used in snapshot range query processing to prune the search space was shown. SKNN estimated the subspace containing the query results and used the subspace as range to efficiently compute the KNN POI from the query points to reduce I/O cost and time of query. Analysis shows that the maximum bound can be used in snapshot range query processing to prune the search space. The contrast experiments show that SKNN has better system throughput than S-GRID while scaling to hundreds of thousands of moving objects.

Establishment and analysis of multi-association rule mining model of reader loan

WANG Jia-sheng MU Xiao-guang

2011, 31(11):  3084-3086.  DOI: 10.3724/SP.J.1087.2011.03084

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In order to probe deeply the demand rules of college library readers, readers' loan records were extracted from working database of college library, and the readers' loan item sets were got by preprocessing the initial data. Multi-association rule mining model of reader loan was established based on Clementine 12.0. Based on the readers' loan records from working database of Qingdao Agricultural University, the associational relations among identities of reader, specialties of reader and categories of book were analyzed by using the mining model. According to the association rules which were mined, the demands for readers can be understood better, which provides theoretical foundation for offering personalized services to readers.

Application of machinery manufacturing decision-making based on ID3 algorithm

LU Zhao CHEN Shi-ping

2011, 31(11):  3087-3090.  DOI: 10.3724/SP.J.1087.2011.03087

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In order to improve the quality management and enhance the efficiency of decision-making in machinery manufacturing industry, this paper took the typical machinery enterprise’s business as an example and explored the data of management information by Cross-Industry Standard Process for Data Mining (CRISP-DM) standard process. By using the gain ratio calculation method based on ID3 decision tree algorithm, the study generated a decision tree model and made it an initial implementation in the company’s Enterprise Resources Planning (ERP) system. By test and analysis, the result shows that the model can standardize the business process and enhance the decision-making efficiency.

Artificial intelligence

Multi-objective optimization of constrained parallel hybrid electric vehicle based on SPEA2

YU Xin-bao LI Shao-bo YANG Guan-ci QU Jing-lei ZHONG Yong

2011, 31(11):  3091-3093.  DOI: 10.3724/SP.J.1087.2011.03091

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Weight coefficients should be employed to transform multi-objective problem of hybrid system into a single objective one. In order to avoid setting weight coefficients, a methodological approach based on Strength Pareto Evolutionary Algorithm (SPEA2) was proposed to optimize parameters of constrained Parallel Hybrid Electric Vehicle (PHEV).The Pareto dominance principle was employed to judge candidate solutions and the objective was to minimum fuel consumption and exhaust emissions while ADVISOR was used to simulate the PHEV driving. The optimal results demonstrate that adopting the methodological approach proposed in this paper to optimize parameters of power control strategy and drivetrain has a significant effect on enhancing working efficiency, promoting vehicle performance, decreasing fuel consumption and reducing exhaust emissions of PHEV.

Two dimensional numerical integration based on particle swarm optimization with constriction factor algorithm

SHI Mei-zhen LIN Jian-liang

2011, 31(11):  3094-3096.  DOI: 10.3724/SP.J.1087.2011.03094

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A new method was presented to calculate two dimentional numerical integration based on Particle Swarm Optimization （PSO） with a constriction factor, named PSO-CF. PSO-CF algorithm selected some initial partition points randomly in the domain,and used the constriction factor to update the velocity,then the particles would move towards better position.This algorithm evaluated particles by fitness value based on the four vertices, four interior points and the center point of every small rectangle after partition, it optimized the particles through repeated iteration. For the opitimal particle, PSO-CF algorithm used the composite four interior points to calculate two dimentional numerical integration. The experimental results show that integral precision is higher,and this method is effective.

Differential evolution algorithm with different strategies and control parameters

QU Fu-heng HU Ya-ting YANG Yong SUN Shuang-zi YUAN Li-hong

2011, 31(11):  3097-3100.  DOI: 10.3724/SP.J.1087.2011.03097

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An improved Differential Evolution (DE) algorithm was proposed to solve the problem of premature convergence and improve the computational efficiency of DE. Firstly, different strategies with different parameter values were adopted to enrich the population diversity. Secondly, a new evaluation index was established to determine the suitable combination to match different phases of the search process. Finally, the evolution process was divided into many subprocesses to eliminate the negative effect of the previously selected combination. The contrast experimental results on ten classical Benchmark functions show that the proposed algorithm has a relatively better performance.

Differential evolution algorithm with dynamically adjusting number of subpopulation individuals

XU Song-jin LONG Wen

2011, 31(11):  3101-3103.  DOI: 10.3724/SP.J.1087.2011.03101

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A novel parallel differential evolution (NPDE) algorithm with dynamically adjusting the number of subpopulation individuals was proposed for solving complex optimization problems. In the NPDE algorithm, the initial population was divided into three subpopulations based on the fitness values of individuals, which were employed for global and local search respectively. The number of the subpopulation was dynamically adapted according to the search phases. Different mutation strategies were used to different subpopulation respectively. It coordinated the exploitation ability and the exploration ability of algorithm. Experiments concerning various benchmark functions were designed to test the performance of the NPDE algorithm, and the results show that it can get high performance while dealing with various complex problems.

Ant colony optimization based on window updating for time series segmentation

LIU Hui-bin HE Zhen-feng

2011, 31(11):  3104-3107.  DOI: 10.3724/SP.J.1087.2011.03104

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This paper applied a modified algorithm of Ant Colony Optimization (ACO) for time series segmentation, which updated pheromone based on window according to the inner continuity of time series for improving optimization efficiency. The algorithm strengthened pheromone according to series continuity; thus, it can improve the positive feedbacks of ants. Then the positive feedbacks were a help for ants to choose paths in the next cycle. The experiments with true data sets validate that the modified method can accelerate the algorithm's convergence and reduce the segmentation cost to a certain extent.

Semi-supervised learning listwise ranking functions for document retrieval

HE Hai-jiang LONG Yue-jin

2011, 31(11):  3108-3111.  DOI: 10.3724/SP.J.1087.2011.03108

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An iterative co-ranking algorithm, which aimed to extend learning to rank from a supervised setting into a semi-supervised setting, was proposed. The approach employed two listwise rankers to identify document permutations for an unlabeled query. In particular, the use of likelihood listwise loss was introduced to measure the difference score of two learners for a given query. The unlabeled query which showed significant difference score was then chosen for constructing the newly training dataset at next iteration, and its ideal document permutation for a listwise ranker was defined by another learner. The experimental results show that the proposed method can improve the ranking performance of supervised listwise ranking algorithm on the public dataset LETOR. In addition, the labeling ratio was also discussed.

Smooth trajectory planning for mobile robot in multi-obstacle environment

YU Xin-yi

2011, 31(11):  3112-3115.  DOI: 10.3724/SP.J.1087.2011.03112

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According to the model of parameterized trajectory generation of wheeled mobile robot, integrating obstacle model in multi-obstacle environment, putting obstacle model into model of parameterized trajectory generation, the common smooth parameterized trajectory planning method of wheeled mobile robot in multi-obstacle environment was obtained. Using methods of optimal control, parameterized optimal trajectory generation model for wheeled mobile robot in arbitrary performance index was constructed in multi-obstacle environment. By means of numerical method, solving method for model of the nonlinear trajectory generation was introduced in detail. At last, the simulation results verify that model of parameterized trajectory planning for wheeled mobile robot in multi-obstacle and its solving method are valid.

Typical applications

Research on impedance characteristics of voltage regulator module in high-performance computer

YAO Xin-an SONG Fei HU Shi-ping

2011, 31(11):  3116-3119.  DOI: 10.3724/SP.J.1087.2011.03116

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To solve system instability caused by the interaction between individually designed power modules/sub-systems in high-performance computer, the input and output impedance characteristics of voltage regulator module for multi-core processor were thoroughly studied. The small-signal model and system block diagram of voltage regulator module were developed, and various transfer functions were presented. Then, the feedback compensator was designed, and the open-loop and closed-loop impedance characteristics were simulated and measured. The simulation and measurement results lay a foundation for the improvement of system stability.

Theoretical model and empirical study on users' acceptance behaviour toward hedonic information system

LIU Lu-chuan SUN Kai

2011, 31(11):  3120-3125.  DOI: 10.3724/SP.J.1087.2011.03120

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Based on the framework of Technology Acceptance Model (TAM), this paper built the users' acceptance behaviour theoretical model of hedonic information system by theory analysis and adding new variables, in order to reveal the users' acceptance behaviour rules of mobile reading. This paper collected data by questionaire, analyzed data, tested hypothesis and modified model with SPSS and AMOS. Results reveal that electronic service quality has positive relationship with perceived usefulness and perceived ease of use, which makes up the defect that TAMs do not pay enough attention to the external factors; users' flow experience has positive relationship with attitude and intention, which breaking through TAM's rational behaviour premise. It expands TAM by introducing the emotional variables that reflect users' emotion on hedonic information system.

Passenger flow distribution in rail transit no-barrier transfer mode

LU Li-neng LIU Jian-ping

2011, 31(11):  3126-3128.  DOI: 10.3724/SP.J.1087.2011.03126

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Passing-by passenger flow is the basis of rail transit passenger analysis. Based on the bus Origin-Destination (OD) matrix estimation model, attraction weight coefficient method was introduced into passenger flow research in rail transit no-barrier transfer mode. Using passenger entry and exit data from Automatic Fare Collection (AFC) system as input, a new passenger flow analysis model was presented. Passengers transfer times and passing-by stations (distance factor) were considered in this passenger distribution method. The case indicates that it can increase the accuracy to consider the range of passenger flow peak.

System design and implementation of tele-autonomous mobile robot

XIA Gui-hua YANG Sheng CAI Cheng-tao

2011, 31(11):  3129-3131.  DOI: 10.3724/SP.J.1087.2011.03129

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Teleoperation control system of autonomous mobile robot was established to solve the incomplete autonomy level of the mobile robots in some specific circumstances.The transmission of panoramic images based on perspective decoding and multi-functional remote control platform based on USB joystick were both developed by the way of wireless networks communication.The fuzzy algorithm for the robot to avoid obstacles independently via ultrasonic sensors, the programme of remote operation of the robot by USB joystick as well as panoramic camera perspective solving principles and video compression were elaborately described in this paper. The experimental results show that the construction of the teleoperation control system can realize a good human-machine interaction, make autonomy of the mobile robot much stronger and more intelligent.

Design and application of automatic scholarship distribution method based on Q-value method

SHAO Zheng-long WANG Que ZOU Xiang-rong

2011, 31(11):  3132-3134.  DOI: 10.3724/SP.J.1087.2011.03132

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In order to achieve the seats fairness and amount fairness of scholarship distribution among the departments, based on Q-value method of seats distribution problem, the multi-step automatic distribution method computes unfairness value in seats distributes and amount distributes, first distributes the seats, then distributes a specific award to a department which has a seat according to the amount of the awards and the total award money of the department. The distribution results of the method were compared with the results of other three distribution methods and got better results. This method had been applied in the post-graduate scholarship system of Tsinghua University, and achieved good effect.

Multi-Agent based dynamic pricing algorithm for seasonal goods

LU Hui

2011, 31(11):  3135-3139.  DOI: 10.3724/SP.J.1087.2011.03135

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This paper is concerned with dynamic pricing problems of seasonal goods based on multi-Agent. The Q-learning algorithm and the Wolf-PHC (Win or Learn Fast, Policy Hill-Climbing) algorithm were proposed to learn the dynamic pricing model of seasonal goods which the two providers did not exchange information with each other. Finally, the paper obtained the simulation results of DF (Derivative Following) method, the Q-learning pricing algorithm and the Wolf-PHC pricing algorithm, and the compared results show that the Wolf-PHC pricing algorithm has a more effective optimization.

Air-raid target threat degree evaluation based on entropy TOPSIS method

ZHANG Xu-dong PENG Jie JI Jun

2011, 31(11):  3140-3142.  DOI: 10.3724/SP.J.1087.2011.03140

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For air-raid target the surface warship threat assessment is the basic foundation of firepower organization. To solve the shortcomings of traditional approximation method, Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), for order preference by similarity to solution in calculating the weights, an improved TOPSIS based on entropy was applied to the multi-target threat problems with weights unknown. This algorithm used entropy theory to process air-raid target objective information, determined each attribute weights of the goal. Then, the weights were applied to the TOPSIS model, and the evaluating model and algorithm of multi-target threat which based on modified TOPSIS model were given. The method is proven to the reasonable and valid by the practical example.

Joint method of realizing PIS of non-monotonic coherent fault tree

LUO Ze-lin REN Qiang LUO Hang

2011, 31(11):  3143-3148.  DOI: 10.3724/SP.J.1087.2011.03143

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The function of non-monotonic coherent bottoms may be covered if getting Minimum Cut Set (MCS) of non-monotonic coherent fault tree with "non-normal" Binary Decision Diagram BDD (BDD) technique. In this paper, a sort of normal BDD technique with the form of uniform code was put forward to conveniently get MCS of non-coherent fault, which was based on inherit technique. Then, the whole process of getting Prime Implicants Set (PIS) of non-monotonic coherent fault was researched by means of combining with Q-M algorithm. The practical example shows that the method can not only accurately get MCS of non-monotonic coherent fault tree, but also automatically gain its PIS.

Ground-based GPS water vapor tomography based on algebraic reconstruction technique

WANG Wei WANG Jie-xian

2011, 31(11):  3149-3151.  DOI: 10.3724/SP.J.1087.2011.03149

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The algebraic reconstruction technique family, including Algebraic Reconstruction Techniques (ART), Multiplicative Algebraic Reconstruction Techniques (MART), Simultaneous Iterative Reconstruction Techniques (SIRT), was studied to reconstruct the three-dimensional distribution of water vapor in this article. The simulation experiment was carried out on Shanghai GPS network. The results show that the algebraic reconstruction technology family can work effectively in water vapor tomography, get rapid convergence, and implement more easily. The range of relaxation factor and the initial value of iteration were also given in the article.

Indoor positioning system for bluetooth cell phone

ZHANG Hao ZHAO Qian-chuan

2011, 31(11):  3152-3156.  DOI: 10.3724/SP.J.1087.2011.03152

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This paper introduced a low-cost platform for locating bluetooth cell phones and releasing position information. The authors improved the scheme of measuring Received Signal Strength Indication (RSSI) of bluetooth devices to locate multiple cell phones simultaneously, developed cell phone program to receive position information via Wi-Fi and display it on map. The experimental results show that the system is accurate in positioning and easy to use, and it provides a platform support for applications of Internet of Things (IOT) under current hardware condition.

Analysis on phase space reconstruction and chaotic dynamic characteristic of ship's sailing data

HUANG Qian LI Tian-wei YANG Shao-qing LI Zheng-you

2011, 31(11):  3157-3160.  DOI: 10.3724/SP.J.1087.2011.03157

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Phase space reconstruction is an important part in recognizing chaos during ship's sailing, it directly influences the result of chaotic analyzing and the effect of chaos controlling. In order to choose a proper method, this paper reconstructed the ship's sailing data series by two methods, and compared the performances of reconstructions. It is proved that the C-C method does well on processing ship's sailing data series, while the autocorrelation &G-P method does a little bad. Different methods were used to conduct qualitative analysis and quantitative analysis based on the phase space reconstruction, the results of the analysis show the existence of chaotic characteristic in the ship's sailing data series, which provides the following research on ship's chaos control with essential basic data and comparison foundation.

Ship video transmission and protection system based on 3G network

ZHAI Xiao-yu CHEN Zhao-zheng CHEN Qi-mei

2011, 31(11):  3161-3164.  DOI: 10.3724/SP.J.1087.2011.03161

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The control and treatment of water pollution is an important issue in China. To meet the lack of remote monitoring of water, the ship video transmission and protection system based on 3G network was proposed. The structure of the system was described, and the characteristics of the 3G network video transmission were analyzed. The achievement of smooth real-time video transmission was based on 3G network, simple reliable user datagram protocol, H.264 video codec, and Quality of Service (QoS) control. The results show that the system is effective, and it can be applied to real-time video surveillance of water.

M2M monitoring terminal based on Cortex-M3

ZHANG Xin DING Zhi-gang ZHENG Shu-quan

2011, 31(11):  3165-3168.  DOI: 10.3724/SP.J.1087.2011.03165

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After research of the application of Internet of Things (IOT) in industrial control field, according to the monitoring terminal problems that large volume,low-capacity and simple function, a miniaturized, high-capacity, strong real-time, multi-parameter M2M monitoring terminal was designed and implemented. The terminal designed a basic control module, and the default for different applications and options that could be equipped with modules and applied more broadly. It achieved dynamic configuration of network interfaces and improved the versatility of the terminal. Learning from the traditional mode of data acquisition, the paper devised a prioritization scheme of data acquisition and data transmission, and discussed optimization algorithm. The results of applications show that it is a noticeable improvement in the index of system overhead and data transmission.