2008 Vol.26

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    Structure Security of Compress Function of SHA-256
    LI Chao;WEI Yue-chuan;SUN Bing
    Journal of Applied Sciences    2008, 26 (1): 1-1.  
    Abstract2455)            Save
    The paper presents three kinds of variant forms of compression functions of SHA-256, and analyzes security of three variants against the Chabaud-Joux attack compared with SHA-256. The complexity of finding a local collision in SHA-2A is similar to SHA-256,SHA-2B does not exist a low complexity collision, but exist other faults in it’s structure,while SHA-2C is far insecure than SHA-256. Furthermore, a local collision in the vulnerable variant is presented. It follows that the selection of the compression function’s structure highly affects the complexity of the attacks.
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    Cited: Baidu(4)
    Design of Link-State Based Inter-domain Routing Protocol
    XIONG Huan;CHEN Ming
    Journal of Applied Sciences    2008, 26 (1): 6-6.  
    Abstract1900)            Save
    To improve scalability, convergence and route quality of inter-domain routing, a link-state based inter-domain routing protocol is designed. The status of autonomous system level network is first modeled. Combined with the status information of inter-domain connections, the shortest path algorithm is implemented to calculate the inter-domain route. The routing model and the mechanism of inter-domain routing policy are discussed.The protocol performance is analyzed and compared with BGP. The analysis and simulation results show that the link-state based inter-domain routing protocol can reduce routing table size,and improve convergence and route quality.
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    Low Complexity Resource Management for OFDM Systems Based on GPS Scheduling
    ZHOU Jing;JING Zhi-hong
    Journal of Applied Sciences    2008, 26 (1): 12-12.  
    Abstract2379)            Save
    A low complexity resource management scheme based on generalized processor sharing (GPS) scheduling for the downlink of OFDM systems is proposed. By using the MAC-PHY cross-layer design method, the proposed scheme gives a good tradeoff between channel capacities and user fairness. It can achieve fair bandwidth sharing among users by GPS scheduling in the MAC layer, while integrating sub-optimal subcarrier allocation, equal power distribution and adaptive modulation to exploit the available channel capacities in the PHY layer. Furthermore, we propose a weight compensation method to improve fairness of GPS bandwith sharing. Numerical results demonstrate that the scheme offers performance comparable to an existing algorithm, with lower computational complexity.
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    Cited: Baidu(7)
    A Rate Adaptation Mechanism Based on Channel State in Ad Hoc Network
    CHENG De-feng;MA Yi-fei
    Journal of Applied Sciences    2008, 26 (1): 18-18.  
    Abstract2317)            Save
    An analytic formula of saturation throughput is presented for multi-hop Ad Hoc networks, which takes packet collision and channel conditions into account. Based on the formula, a rate adaptation mechanism is proposed. The scheme can adjust the rate of sending packets exactly, and choose the optimal size of packets to best match channel conditions for maximizing saturation throughput. Simulation results show that the scheme outperforms OAR and 802.11 DCF with 10% and 260% improvement on the saturation throughput and channel-resiliency capability.
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    Cited: Baidu(44)
    Adaptive Shrinkage Image Denoising in Curvelet Domain
    DENG Cheng-zhi;CAO Han-qiang;WANG Sheng-qian
    Journal of Applied Sciences    2008, 26 (1): 22-22.  
    Abstract2400)            Save
    A nonparametric Bayesian estimator for image denoising in the curvelet domain is studied. A prior model, named normal inverse Gaussian (NIG), is imposed on the curvelet coefficients designed to capture the sparseness of the curvelet expansion. Based on this, a NIG-based maximum a posteriori (MAP) estimator is designed. By estimating the model parameters of curvelet subband coefficients, a MAP-based subband adaptive shrinkage image denoising is realized. Simulation is carried out to show effectiveness of the denoiser. Experimental results show that the proposed method can effectively reduce noise while keep details.
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    Cited: Baidu(12)
    A Novel Histogram Similarity Measure Using Average Translation of Bins
    MA Yu;GU Xiao-dong;WANG Yuan-yuan
    Journal of Applied Sciences    2008, 26 (1): 28-28.  
    Abstract2348)            Save
    Previous histogram similarity measures have disadvantages when several kinds of deformation happen to the histograms. A novel similarity measure is proposed based on average translation of histogram bins. The value differences of both corresponding and cross bins are calculated to get the average difference against bin distances, and the average translation of bins is used to measure the histogram similarity. Experiments on intensity histograms of images influenced by noise and illumination are carried out to compare the performance of different kinds of similarity measures. The results show that average translation of bins as a histogram similarity measure outperforms other measures under the condition of histogram deformation. It consists with the other measures under general conditions. Preliminary studies on the measure’s usefulness in image retrieval and object searching indicate its potential applications based on image histograms.
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    Cited: Baidu(6)
    Semi-fragile Image Watermarking Based on RS Codes
    LIU Cui-Qing;PING Xi-Jian;ZHANG Tao;WANG Yun-He
    Journal of Applied Sciences    2008, 26 (1): 34-34.  
    Abstract1941)            Save
    The proposed semi-fragile watermarking scheme is realized using the RS error-correcting codes and wavelet decomposition. While the encoding data of RS codes are composed of an authentication key and selected wavelet data of an image, the checked data of RS codes carry the digital watermark and are embedded into different sub-bands in the wavelet domain of the host image, achieving semi-fragility. Theoretical analysis indicates that the proposed scheme is capable of identifying the authenticators with the authentication key data.
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    Cited: Baidu(2)
    Prediction of Transmembrane Helical Segments in Membrane Proteins Based on Discrete Wavelet Transform
    YU Bin;WANG Guang-bin;WANG Yi-fei
    Journal of Applied Sciences    2008, 26 (1): 40-40.  
    Abstract2288)            Save
    Increasing protein sequences from the genome project require theoretical methods to predict transmembrane helical segments (TMHs). In this paper, a method based on discrete wavelet transform (DWT) is developed to predict the number and location of TMHs in membrane proteins. PDB coded as 1KQG is chosen as an example to describe the prediction process with this method. Eighty proteins with known 3D-structure from the Mptopo database are chosen at random as the test objects (including 325 TMHs), 312 of which can be predicted and the prediction accuracy is 96.6%. Compared with main prediction results of seven common prediction methods, the obtained results indicate that the proposed method has higher prediction accuracy.
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    Partial Transmit Antenna Selection for V-BLAST System
    ZHANG Xiao-ge;XU Cheng-qi
    Journal of Applied Sciences    2008, 26 (1): 45-45.  
    Abstract2186)            Save
    A vertical bell laboratories layered space-time (V-BLAST) system with partial transmit antenna selection is studied. The first layers are separated from the remaining layers by an incomplete QR decomposition. Then, the corresponding antennas are selected according to a certain selection criterion and the first layers are detected. After eliminating contributions of the first layers from the received signals, the remaining layers are also detected. Compared with conventional selection methods, this selection scheme provides multiple trade-offs between complexity and performance according to . Simulation results show that the partial transmit antenna selection retains most of the symbol error ratio (SER) performance of the full selection system. For a 4 transmit RF chains with 4 receive RF chains and 6 transmit antennas, simulation results show that the partial transmit antenna selection based on the max-min criterion can save about 40% up to 92% of the selection time required for the full selection system.
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    Design and Realization of Harmonic-Suppressed Low-Pass Filter Using Defected Ground Structure
    Qi Yu-jie;Liu Xue-guan
    Journal of Applied Sciences    2008, 26 (1): 51-51.  
    Abstract2001)            Save
    This paper presents a method to use the equivalent-circuit model and 3-D model simulation for the DGS to extract the dimension parameters. Combining an inter-digital elliptic-function low-pass filter with the DGS structure, a novel filter is proposed. A compensated feed-line structure on the side of the inter-digital elliptic-function low-pass filter is designed, and a couple of suitable DGSs are etched under compensated lines. Furthermore, full-wave simulation and optimization of the proposed filter are obtained with HFSS to get better impedance match. The design gives performances of a flat passband, a wide stopband and a compact structure. Agreement between experimental results and measurements shows validity of the DGS filter, which has good harmonic-suppressed characterizes.
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    Cited: Baidu(3)
    Decision Domain Based Flow-Aware Admission Control
    QIU Gong-an;ZHANG Shun-yi
    Journal of Applied Sciences    2008, 26 (1): 55-55.  
    Abstract2046)            Save
    To avoid the decision error of single information based flow-aware admission control, four 2D state spaces are established using priority queue length and link fairness rate to describe the information of different link states. According to the flow distribution under different link states, four state spaces are mapped into three integrated decision domains. The integrated decision table based on the integrated decision domain is the decision conditions for proposed admission control algorithm. The formula of blocking probability for real-time flows is derived, and the average throughput for elastic flows obtained. Simulation results show that the proposed algorithm can reduce the delay of real-time flows by 10% and increase the average throughput of elastic flows by 25.75% with approximately 5.44% increase of the blocking probability for real-time flows when overloaded.
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    Cited: Baidu(8)
    Algorithm Management Framework for Data Stream Mining
    ZHU Xiao-dong;HUANG Zhi-qiu;CHEN Sheng-qing;HUANG Feng;SHEN Guo-hua
    Journal of Applied Sciences    2008, 26 (1): 61-61.  
    Abstract2367)            Save
    In developing algorithms for data stream mining, little work has been done in the management of various algorithms. Although there have been many effective algorithms developed specifically for data stream mining, the application rate is quite low. In this research, we establish a process model for data stream mining. A process model for the algorithm management framework based on web services, PMAMF-DSM, is proposed. We analyze the construction of data stream algorithm repository and the architecture of the framework. Using the framework, a data stream oriented algorithm management system is implemented on Eclipse. Experiments indicate that the framework has high flexibility and self adaptability.
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    Augmented Reality Registration Algorithm Based on Line Features
    ZHAO Xin-can;ZUO Hong-fu
    Journal of Applied Sciences    2008, 26 (1): 68-68.  
    Abstract1964)            Save
    A system model of markerless registration with line feature is presented. The complicated registration problem is divided into four steps: feature extraction, matching, 3D reconstruction, and merge of virtual and real scenes. Key techniques and theories in each step are discussed. Using the technique of structure from motion, AR markerless registration is achieved by 3D line tracking. Experimental results indicate that the proposed algorithm is effective.
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    Cited: Baidu(2)
    Mapping from Feature-Based Requirement Model to Agent-Oriented Conceptual Architecture
    LIANG Jun-tao;JIANG Xiao-yuan
    Journal of Applied Sciences    2008, 26 (1): 74-74.  
    Abstract2103)            Save
    Mapping from requirements to agent-oriented software architecture keep the traceability in concepts between requirements and designs. Make use of feature model, analysis feature dependencies of feature model and dependencies of agent. Then feature exist dependency and feature value dependency are proposed. A mapping approach from feature model to agent-oriented conceptual; architecture is introduced. The approach is illustrated by an example of library management system
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    Support Vector Date Description Implemented in Class-Imbalance Learning
    MIAO Zhi-min;HU Gu-yu;DING Li;ZHAO Lu-wen;PAN Zhi-song
    Journal of Applied Sciences    2008, 26 (1): 79-79.  
    Abstract2427)            Save
    In this paper, an I-SVDD algorithm for two-class imbalance problem is proposed, which based on Support Vector Date Description algorithm. In this algorithm, the C value of SVDD with negative sample is redefined for each sample with data distributing information. We verified the efficiency of algorithm using artificial data and UCI datasets for the data unbalanced classification problem. Compared with SVDD with negative samples, the AUC value of I-SVDD is increased by 12%. Compared with AdaBoost, the recall of positive class is increased by 35%,and the precision increased by 2%.
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    Cited: Baidu(7)
    Neural Network Control for Semi-active Suspension Automobile
    Qiu Hao;Xiong Zhi
    Journal of Applied Sciences    2008, 26 (1): 85-85.  
    Abstract2211)            Save
    Regarding drawbacks of the standard BP algorithm, a high-order derivative based multiple memory BP algorithm is proposed. It combines the n-th order of energy function with the direction of the fastest decline to construct a new direction of the fastest decline, and improve the learning speed of the neural network. The new algorithm is compared with the traditional gradient algorithm to show its high computation speed. Implementation of the new algorithm is given. Finally a neural network controller is designed to optimize the performance of the automobile suspension. The result shows that the new algorithm is convenient and effective.
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    Adaptive Fuzzy Observer Design for a Class of Nonlinear System
    WANG Yong-fu;ZHAO Hong;LIU Ji-ren;CHAI Tian-you
    Journal of Applied Sciences    2008, 26 (1): 89-89.  
    Abstract2609)            Save
    We propose a method of adaptive fuzzy observer design for a class of uncertain nonlinear systems. The observer uses fuzzy system to approximate nonlinear functions so that the structure and parameters of the observed object are not needed in the design. The estimation error, approximation error and external disturbance are supervised by a robust term to provide favorable observation performance. This observer is an extension for the nonlinear Luenberger adaptive observer. Effectiveness of the method is proven theoretically and verified in simulation.
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    Cited: Baidu(3)
    Fast Dynamic North-Seeking of FOG Based on Wavelets
    LIU Dong-bo;LIU Jian-ye;LAI Ji-zhou
    Journal of Applied Sciences    2008, 26 (1): 95-95.  
    Abstract2347)            Save
    Regarding applications of low-precision and medium-precision fiber-optic gyroscope (FOG), we present a fast north-seeking algorithm based on wavelet transform. The proposed method imports continuous slow-speed rotation, changes static measurements into dynamic measurements under the leveling condition. Measurement noise is suppressed, and the useful information of FOG output is kept with wavelet transform filtering. Consequently the influence of FOG’s low-frequency random drifting is reduced. Thus the FOG can find the geographical north fast and accurately. Experimental results show that the method can effectively reduce the time needed to seek north and errors in repetitive north-seeking, and improve direction accuracy. The method is expected to have theoretical and practical values.
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    Cited: Baidu(13)
    Design of Cellular Manufacturing System Based on Matrix Clustering Algorithm
    ZHU Heng-yun;YE Wen-hua
    Journal of Applied Sciences    2008, 26 (1): 100-100.  
    Abstract2161)            Save
    In recent years, cellular manufacturing system (CMS) is considered as an advanced manufacturing system that can meet variable customer demand, short product life cycle, and increasing worldwide competition. In this paper, a method for designing CMS based on a new matrix clustering algorithm is proposed. Compared to other clustering algorithms such as ROC, ROC2 and DCA in terms of grouping efficiency and grouping efficacy, the method is feasible and with higher efficiency. The elements in machine component matrix are modified from binary to non-binary elements, which provide information of actual intercellular flows of components. This change can provide a more reasonable clustering result than other methods.
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    Cited: Baidu(3)
    Influence of Stretching Fixation on TC4 Ti Alloy Milling Surface Quality
    XU Hong-hao;ZUO Dun-wen;ZHU Xiao-xiao;ZHANG Zhen-jin;ZHAO Can;WANG Min
    Journal of Applied Sciences    2008, 26 (1): 106-106.  
    Abstract2108)            Save
    Stretching fixation was proposed to improve milling surface quality of TC4 Ti alloy. A plane strain model was developed to analysis the residual stress variation of stretching-fixation milling surface. With a unidirectional mechanical stretching fixture, a stretching-fixation milling experiment was completed on an HSM-600U five axis super-high speed machining center. This was done with the milling speed ranging from 38m/min to 566m/min and the stretching force from 0 to 6330N, and other parameters being kept constant. Surface roughness and residual stress distribution were measured. Experimental results show that stretching fixation has little effect on surface roughness, while increases surface residual compression stress and thickness of residual compression stress layer significantly.
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    Classification of Modulation Techniques Using Constellation Shape and Similarity Measure
    Journal of Applied Sciences    2008, 26 (2): 111-111.  
    Abstract2688)            Save
    In this paper, we study the problem of modulation classification in the presence of phase error and improve modulation classification algorithm which uses constellation shape as classification signature. First, dynamic clustering algorithm is utilized to recover unknown constellation based on similarity between samples and kernels. Then recovery constellation is matched with constellations of different modulated signals and classified by a proposed max-likelihood rule, which is simple and equivalent to minimum distance classification rule. This rule avoids a training phase which is necessary for spatial statistics of recovery constellation vertices in previous algorithms. Considering the effect of additive noise on phase estimation, simulations show that the correct rate is above 90 percent when SNR is 10db and 15db respectively under the condition of known and unknown number of modulation states.
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    Cited: Baidu(8)
    Design and Implementation of Embedded Radio Network Management Model Based on SNMP Protocol
    XIAO Zhe;CHEN Bing
    Journal of Applied Sciences    2008, 26 (2): 117-117.  
    Abstract2056)            Save
    he widespread application of embedded wireless network equipment requires better management of the network. This paper takes subway wireless communication system as an application scenario. An embedded radio network management model is constructed based on the Simple Network Management Protocol (SNMP). The private wireless-related MIB of embedded radio is defined on ASN.1, and function modules of agent are designed. After cross compiling and transplanting the agent, we have implemented the function of network management. Test results show that the agent has a good compatibility, and extra load of system to the network is tolerable.
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    Cited: Baidu(2)
    Ultra-wideband Wireless Communication Based on Chirp-BOK-BPSK Modulation
    FENG Jin-Zhen;ZHENG Guo-Xin
    Journal of Applied Sciences    2008, 26 (2): 123-123.  
    Abstract2418)            Save
    Based on strong autocorrelation of up-chirp and down-chirp, and extra-low cross-correlation between them, and using Chirp-BOK, we propose the Chirp-BOK-BPSK modulation that can be used in UWB wireless communication system. In this scheme, input data are modulated onto both phases of the Chirp and slope of instantaneous frequency. The BER performance of Chirp-BOK-BPSK UWB scheme is analyzed in an AWGN environment. In the indoor setting, however, the system shows seviere ISI. Simulation has been done to obtain BER performance of the Chirp-BOK-BPSK and compared with the Chirp-BOK UWB. The results show that BER of Chirp-BOK-BPSK is less than 10-4 at a 12dB SNR.
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    Cited: Baidu(7)
    Orthogonality and Power Spectra of EBPSK Modulated Waves
    ZHANG Shi-kai;WU Le-nan
    Journal of Applied Sciences    2008, 26 (2): 127-127.  
    Abstract2188)            Save
    Waveform orthogonality has a direct influence on signal bandwidth and demodulation. The paper obtains orthogonal EBPSK signals and power spectrum by deriving EBPSK correlative expression and power spectrum expression. The best power spectrum condition, duty cycle of one and phase shift of π/2, are given. This is helpful in parameter selection of EBPSK waveform control. As the symbol correlativity is increased, the power is more concentrated but with poorer demodulation performance. On the other side, with symbol correlativity decreased, performance of demodulation is improved, but power becomes more distributed. The best orthogonal power spectrum can reduce line spectrum components, make power concentrated and spectra compressed. Thus bandwidth efficiency is improved and, at the same time, performance of demodulation is also improved for symbol orthogonality. Therefore a good tradeoff between symbol correlativity and demodulation performance is obtained.
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    Cited: Baidu(22)
    XOR Approximation of Modulo Addition for Cryptanalysis
    ZHOU Yue;LI Rui-lin;LI Chao
    Journal of Applied Sciences    2008, 26 (2): 132-132.  
    Abstract2322)            Save
    Modern cipher components ususlly combine mixed operations of different groups. In cryptanalysis,one alwalys uses the XOR operation to linearly approximate modular addition,which requires calculation of the distribution of noise.In this paper, we propose a reduced linear representation of such distribution based on the formal power series on free monoid which can be easily used to calculate the pobability diatribution.We also extend the result to the addition modulo p^n.This provides a solid basis for linear cryptanalysis.
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    Cited: Baidu(1)
    Relaxational Smooth Processing for Detection of Weak Concentration Gas
    ZHU Ming;WANG Shu;ZHU Zhen-yu;LIU Li-jing
    Journal of Applied Sciences    2008, 26 (2): 137-137.  
    Abstract2048)            Save

    By analyzing the energy transfer models in molecular collision processes and the acoustic relaxation attenuation in gas, we find the reason of ruggedness in the dependence of molecular multi-relaxation attenuation coefficient on the mixture concentrations when the gas constituents have concentrations less than 0.01%. We use a typical smooth window to process acoustic relaxation attenuation data, and develop an algorithm to detect weak gas concentration of three-component gas mixtures. The measuring accuracy of this method achieves 0.001%. Three designed matrices with different weighted averages can all reduce errors resulting from weak gas concentration. The simulation results of consistent error-reduction using all the matrices show that the relaxation smooth processing algorithm is reasonable.

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    Influence of Alternated Magnetic Field on Ice Crystal Formation Process in Aqueous Solution
    CHEN Zhao-zhang;WANG Heng-hai;HUANG Yong-hong;XU Xiao-bin
    Journal of Applied Sciences    2008, 26 (2): 145-145.  
    Abstract2309)            Save
    Nondestructive cryogenic preservation has been an important research topic in cryobiology. Organisms are mostly composed of aqueous solution. Common methods involve the use of an ultra-rapid cooling rate or a very high concentration of cryoprotectants. Unfortunately, adding cryoprotectants introduces impurities for biomaterials themselves and ultrarapid freezing is very difficult to obtain the same cooling rate for the surface and interior of big samples. The influence of ice crystal formation process in KMnO4 solution by alternated magnetic field was studied under the condition of low cooling rate. Alternated magnetic field was produced based on series resonance. This study shows that 50 kHz alternated magnetic field can suppress ice crystal growth in the solution, and salty ice formed. The result of low freezing rate cryopreservation easy achieved is of great significance, and useful in practical applications.
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    Cited: Baidu(3)
    Prediction of Protein Secondary Structure with an Improved Measure of Information Discrepancy
    LI Zhe-qian;LIU Shu-peng;YAN Zhuang-zhi;XIN Yan-fei
    Journal of Applied Sciences    2008, 26 (2): 150-150.  
    Abstract2092)            Save
    The secondary structure prediction is important in protein structure prediction since protein secondary structure is the basis of the tertiary structure. A method of information discrepancy-FDOD (Function of Degree of Disagreement) was used to predict protein secondary structure in this work. Data were selected from the CB396 database and prediction accuracy was 72.1%. Besides, multiple alignment of PSI-BLAST was used to combine with FDOD, with the prediction accuracy increased to 75.6%. Furthermore, in order to reduce computation complexity, hydrophobic values were introduced to improve the algorithm and the impact factors of hydrophobic values. Long-range interaction is discussed in the prediction of protein secondary structure.
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    RF Front-End Topology Design of Wideband Receivers
    Zhou Jian-zheng;Wang Zhi-gong;Li Li;Wang Ke-ping
    Journal of Applied Sciences    2008, 26 (2): 155-155.  
    Abstract2433)            Save
    A high-side injection, fixed intermediate frequency (IF), double-quadrature-downconversion and low-IF structure is proposed for wideband receivers. Four image rejection ratios (IRR), and relationship between IRRs and the amplitude errors ΔA or phase errors Δθ of two kinds of double quadrature receiver structures (single-double and double-double quadrature structures) are derived. Comparison of these two structures shows that single-double quadrature conversion is more suitable for wideband receivers. To improve IRRs of the system, two modules, RF filter and polyphase filter before the second downconersion, are added to the single-double quadrature structure. The quantitative IRRs performance of the total RF-end and a design example, DRM receiver RF-end, are given. Simulation results show that this RF-end structure has good IRR performance (when -10°≤Δθ≤10°,-0.1≤ΔA≤0.1, IRRs≥61.16dB). This is an ideal structure for wideband radio receivers, combining the inherent characteristics of a low-IF structure such as suitability for high integrality, ability of supporting multi-standard communication, and immunity to parasitical low frequency noise.
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    Cited: Baidu(3)
    Uplink Multi-user Alamouti MIMO Detection with Antenna Selection
    ZHANG Xiao-ge;XU Cheng-qi
    Journal of Applied Sciences    2008, 26 (2): 162-162.  
    Abstract2354)            Save
    To improve the diversity benefit of the uplink multi-user MIMO detection, the ordered successive user cancellation (OSUC) detection and the antenna selection technique are applied. Two antenna selection criteria for OSUC detection called max-min user SINR and max-first user SINR are proposed. The selection criterion for non-OSUC detection called max-min user SINR is also proposed. The Sherman-Morrison formula is used to reduce computation complexity. Simulation results show that OSUC detection obtains only a little more diversity benefit, and antenna selection obtains almost all the diversity benefit of the full complexity system when no less than 2(P-1)+1 antennas are selected.
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    Cited: Baidu(4)
    Circularly Polarized Microstrip Antenna Easily Integrated with Active IC
    SUN Jiang-Tao;YANG Xue-Xia;SHENG Jie
    Journal of Applied Sciences    2008, 26 (2): 167-167.  
    Abstract1914)            Save
    This paper presents a novel unequal cross-slot coupled circularly polarized microstrip antenna excited by coplanar waveguide (CPW), which is convenient to be integrated with active circuits. Influence of the antenna’s size on the characteristics is analyzed using an electromagnetic simulator. A prototype is designed and fabricated. The measured results are in good agreement with simulation. The measured bandwidth of VSWR below 2 reaches 600MHz and axial ratio is 1.7dB in the main direction, with 3dB bandwidth of 140MHz at the central frequency of 10.28GH. Good circular polarization performance has been shown in experiments.
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    Design of Slot Antenna for RFID Tag Using ANN
    ZHOU Yong-ming;LAI Xiao-zheng;LAI Sheng-li
    Journal of Applied Sciences    2008, 26 (2): 171-171.  
    Abstract2730)            Save
    To study the optimized design of slot antenna for RFID tags, attention is paid to optimize design of the slot antenna using artificial neural networks (ANN). Shortcomings of traditional design method with one dimension geometrical parameter for tag antenna have been avoided. The design is consistent with that of IE3D simulation which is based on the method of moment (MOM). A slot antenna for tag is fabricated, and the reading distance is measured with the compatible reader, showing that the slot antenna can meet the requirement of UHF tag.

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    Detection of Anomalous User Behavior Based on Shell Commands and Hidden Markov Models
    TIAN Xing-uang;DUAN Mi-yi;SUN Chun-lai;LI Wen-fa
    Journal of Applied Sciences    2008, 26 (2): 175-175.  
    Abstract2582)            Save
    Anomaly detection is an active research topic in network intrusion detection. This paper presents a novel method for detecting anomalous user behavior based on shell commands and hidden Markov models (HMM). The method constructs a specific HMM to represent the normal behavior profile of a network user, and associates classes of user behavior patterns with states of the HMM. The HMM parameters are calculated with a sequence matching algorithm which is much simpler than the classical Baum-Welch algorithm. This reduces computational complexity to a great extent. At the detection stage, a decision rule based on probabilities of short state sequences is adopted, and more than one threshold are used to classify the user behavior. Performance of the method is tested in computer simulation, showing high detection accuracy and efficiency.
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    OLAP Security Strategy Based on Dimension and Hierarchy of Data Cube

    YANG Ke-hua
    Journal of Applied Sciences    2008, 26 (2): 182-182.  
    Abstract2314)            Save
    By analyzing the hierarchical structure of information in a data cube, security strategy of an online analysis process (OLAP) based on dimension and hierarchy of data cube is proposed. By combining the visit rules with the information of dimension and hierarchy of data cube, the security strategy is easily implemented, and can support OLAP operations more efficiently. Theoretical analyses and experiments show that this security strategy has powerful description ability, simple management and high execution efficiency.
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    Distributed Reservation Architecture of Simultaneous Multithreading Processor

    YANG Hong-bin;WU Yue;LIU Quan-sheng
    Journal of Applied Sciences    2008, 26 (2): 188-188.  
    Abstract2092)            Save
    To improve the high-efficiency parallel processing performance of data flow instruction of a simultaneous multithreading processor, a 7-part distributed reservation architecture is presented. The simultaneous multithreading processor uses committing mechanism for each thread with single reorder buffer and register with smart speed and low complexity of hardware. The parallel degree of data flow instruction is improved for two threads. The function of reservation, committing mechanism and register is validated and simulated. These units are synthesized.
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    Growing Sparse Neural Networks
    FENG Chao;LI Ning;LI Shao-yuan
    Journal of Applied Sciences    2008, 26 (2): 194-194.  
    Abstract2256)            Save

    When using sparse neural networks in practice, it is hard to choose a proper connection rate. In this work, based on new discoveries in the brain science, two new learning algorithms are developed which change the network’s connection structure at the time of learning, thus an accurate connection rate is not needed. Sparse neural networks reduce coupling among inputs so that fewer connections are needed to meet the fitting requirement. Simulation results show that the new algorithms are effective.

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    Measurement and Control of Bimodal Ultrasonic Motor Based on Wavelet Actuation

    XU Congyu;YU Xiaofen
    Journal of Applied Sciences    2008, 26 (2): 199-199.  
    Abstract2492)            Save
    At present, bimodal ultrasonic motor (USM) applied to large displacement actuation and nanometer positioning control uses combination control of the actuation’s modes, namely AC actuation mode, pulse actuation mode and the DC actuation mode. This paper proposes a novel single wavelet actuation pattern of bimodal USM, which can realize step control with the stepping distance adjusted. A wavelet actuation wave is composed of 8 sinusoidal voltage waves of 39.6 kHz, whose maximum triggering frequency is up to 5 kHz. In a positioning control application, the grating with 20?m pitch was selected as the displacement measurement sensor. The fast subdivision formula of mutual compensation functions developed by the author was used as the grating nanometer measurement tool. With the control algorithm of measurement and actuation sequence, the maximum stepping distance of bimodal USM was 2?m and the maximum actuation speed of the stage reached 10mm/s. The experimental results indicate that when the wavelet actuation parameters are properly chosen, nanometer actuation resolution and nanometer positioning accuracy can be reached.
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    Reliable Robust Control for a Class of Uncertain Switched Systems
    DONG Xue-ping;WANG Zhi-quan
    Journal of Applied Sciences    2008, 26 (2): 204-204.  
    Abstract2460)            Save
    Based on the method of Lyapunov function, design of reliable robust controllers is given such that the corresponding closed-loop system is globally asymptotically stable for all admissible uncertainties and actuator failures for a class of uncertain switched systems. Next, with the linear matrix inequalities (LMI) approach, design of robust reliable controllers can be converted into a feasible problem of certain LMI system. The solution of controllers can be efficiently obtained with the Matlab LMI toolbox. A numerical example shows validity of the proposed design method.
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    Tracking Control for a Class of Uncertain Nonlinear Systems with Time-Varying Delay Using Multi-model Switching

    HU Cheng-zhong;QIAN Cheng-shan;YANG Zhao-hua;WANG Yan-qing
    Journal of Applied Sciences    2008, 26 (2): 209-209.  
    Abstract2582)            Save
    This paper studies the design of a tracking control for a class of uncertain nonlinear systems with time-varying delay using multi-model switching in the presence of uncertainty. First, T-S models with time-delay are employed to model the uncertain nonlinear system with time-delay. When uncertainty is gain bounded, a sufficient condition, which satisfies the closed-loop stability and the performance of H∞ tracking, is presented for the existence of the controller. Finally, a region controller, chosen according to the selected variables by the multiple-model switching control, is switched to the whole controller, and other controllers do not operate. Thus the control of the entire nonlinear system is established. Effectiveness of the proposed method is demonstrated with simulation results.
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    Inverse Kinematics for Robot Based on BP Network and Orthogonal Design Experimentation
    XUE Yan-min;LIU Hong-zhao
    Journal of Applied Sciences    2008, 26 (2): 216-216.  
    Abstract2129)            Save
    This paper deals with the inverse kinematics problem of the PUMA560 robot. Based on six similar BP neural networks, the inverse kinematics solution of the manipulator is obtained. The training parameters are obtained by optimized organization using orthogonal design experimentation (ODE). Simulation results indicate that this method has the advantage of fast learning rate, high precision of identification and better real-time capability.
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