2010 Vol.28

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Design of Quasi-cyclic LDPC Code for Fast Encoding FAN Jun1, XIAO Yang2 Journal of Applied Sciences    2010, 28 (1): 1-8.   Abstract （1817）      PDF（pc） （693KB）（2013）       Knowledge map    Save Since the generator matrices of the LDPC code are always non-sparse, it is hard to store a large generator matrix when the code-length is long. Moreover, time complexity of encoding with a generator matrix is high. In order to resolve this problem, we present a new design of quasi-cyclic (QC) LDPC code for fast encoding. Unlike other QC codes, the parity check matrices of the proposed QC codes not only have the quasi-cycle characteristic, but also contain sub-matrices with the quasi-diagonal structures. So the parity check matrices have approximate lower triangular structures. According to Richardson’s fast encoding algorithm, the parity check matrices with these structures can realize fast encoding by the parity check matrices. Therefore we can avoid the difficulties of storage difficulty and time complexity. Simulation in AWGN channels shows that the BER performance of the proposed codes is excellent in different code-lengths and code-rates. Related Articles | Metrics | Comments（0）

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Improved Extended Min-sum Decoding Algorithm of LDPC Codes over GF(q) XU Ba1, ZHANG Zhong-ming1, HE Ying-liang2, ZHANG Er-yang1 Journal of Applied Sciences    2010, 28 (1): 9-13.   Abstract （1913）      PDF（pc） （590KB）（2075）       Knowledge map    Save To overcome the drawback of the extended min-sum algorithm (EMS), an improved EMS decoding algorithm is proposed, which is designed for LDPC over GF(q). The algorithm adaptively chooses the rank of FHT in each iteration step according to the average variance of bit nodes’ probability pairs. It differs from the original EMS algorithm in which the rank of FHT for each iteration step is a constant. Moreover, for oscillating variable nodes, the message of the previous iteration is added to the current message in the iterative procedure to reduce loss of performance and effects of oscillation. Experimental results show that the proposed algorithm can achieve better performance and converge faster than EMS with the same decoding complexity. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Blind Separation and Detection of Chaotic DS Signals Based on ICA XU Wei1;3, HU Tie-hua2, ZHANG Rui-fang1, GUO Jing-bo3 Journal of Applied Sciences    2010, 28 (1): 14-18.   Abstract （1744）      PDF（pc） （644KB）（1578）       Knowledge map    Save Chaotic DS signal is a kind of spread spectrum signal generated by directly modulating information signal with a chaotic signal. Communications using chaotic DS signals instead of conventional direct sequence spread spectrum signals have many advantages such as larger capacity and low probability of intercept. However, detection of chaotic DS signals is difficult. We propose a method to detect chaotic DS signals by calculating the largest Lyapunov exponent of the time series after being separated from the received signals using an ICA blind signals separation algorithm. Simulation results show feasibility of this method under Gaussian noise and multi-path channel interferences. Related Articles | Metrics | Comments（0）

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Bi-mode Based Error Concealment for Stereoscopic Images SONG Li-juan, ZHU Xiu-chang Journal of Applied Sciences    2010, 28 (1): 19-23.   Abstract （1540）            Knowledge map    Save A new error concealment scheme based on bi-mode for stereoscopic images is proposed, which makes use of correlation between the two images and error concealments in monoscopic images based on different local characteristics. Experimental results show that the proposed scheme has good performance of error concealment for stereoscopic images. The average PSNR is increased by 1 dB as compared to the monoscopic mode. Related Articles | Metrics | Comments（0）

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Image Saliency Detection Based on Contrast Features and Local Sharpness YU Zhi-ming, WANG Shuo-zhong, ZHANG Xin-peng, LIU Ting-ting Journal of Applied Sciences    2010, 28 (1): 24-31.   Abstract （1690）      PDF（pc） （6333KB）（2142）       Knowledge map    Save To extract important areas in an image that attract visual attention, a saliency detection scheme using both contrast features and local sharpness in the image is proposed. The local sharpness is related to the focusing status, which reflects the human judgment of the scene being imaged. Therefore, the presented method integrates two different visual characteristics, which we call low- and high-level human visual attention (HVA). The globe and local color contrast in the image arouse the low-level HVA, whereas the local sharpness affects the high-level HVA. Two saliency maps are thus generated with color classification and detailed area detection, respectively, and combined. Experiments show that integration of the saliency maps can provide good correspondence to HVA areas for different images. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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Improved EMD Algorithm and Its Application to Striation Distance Measurement LI Ling1, LI Ming1;2, LU Yu-ming2 Journal of Applied Sciences    2010, 28 (1): 32-37.   Abstract （1534）      PDF（pc） （2078KB）（2088）       Knowledge map    Save Empirical mode decomposition (EMD) is a useful method in nonlinear and non-stationary signal analysis. We propose an improvement to the EMD method to reduce the end effects based on linear prediction. Data are extended by linear prediction until a local extreme appears at each end. The same procedure is applied to each intrinsic mode function. Experiments show that the proposed method works well in restraining the end effects of EMD compared to other methods. Because striation distance in fatigue fracture image is quasi-periodical, striation distance in the horizontal and vertical directions are calculated based on improved EMD algorithm, and the real striation distances obtained through triangle conversion. The striation distance measurement of actual images shows that application of EMD to striation distances measurement is feasible. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Speaker Verification Based on GMM-UBM with Embedded Auto-associate Neural Network CHEN Cun-bao, ZHAO Li Journal of Applied Sciences    2010, 28 (1): 38-43.   Abstract （1824）      PDF（pc） （551KB）（1897）       Knowledge map    Save This paper proposes to embed an auto-associate neural network (AANN) in the Gaussian mixed model-universal background model (GMM-UBM) for speaker verification. The scheme integrates the merits of both GMM and AANN. GMM and AANN are trained as a whole in terms of maximum likelihood (ML), and spatial information of the feature vectors is disclosed. AANN reshapes distribution of the data and improves similarity of intra-class data. In the training, parameters of GMM and AANN are updated alternately. Experimental results show that the proposed method together with TNorm can provide improvement of verification rate by 26% over the baseline GMM-UBM. Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Hash Function Construction Based on Chaotic System of Coupled Map Lattice CHENG Yan-yun, SONG Yu-rong Journal of Applied Sciences    2010, 28 (1): 44-48.   Abstract （1831）      PDF（pc） （589KB）（1836）       Knowledge map    Save A novel scheme for constructing Hash functions is proposed based on the chaotic coupled map lattice (CCML). The initial value, the parameters and the coupled factor of the chaotic dynamical system are modulated by the message plain text blocks, which are mapped directly into the parameter space of CCML. Theoretic analysis and numerical simulation results show that the chaotic initial values, parameter and coupled factor of the CCML-Hash algorithm have high sensitivity. It has good performance such as excellent one-way property, confusion and diffusion characteristics, and strong collision resistance. Related Articles | Metrics | Comments（0） Cited: Baidu(8)

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Identification of Array Signal Parameters Based on Matrix Decomposition LIU Xu, XU Zong-ze, LEI Lei Journal of Applied Sciences    2010, 28 (1): 49-55.   Abstract （1740）      PDF（pc） （545KB）（1764）       Knowledge map    Save We study parameter identification of uniform linear array signals in this work. The received signal matrix is uniquely decomposed under the Vandermonde structure constrains. Parameters of the signal received from uniform linear antennae (ULA) are then identified by exploiting the permutation lemma. The result is extended to the case of dependent sources and multipath transmission by exploiting the property of Khatri-Rao product structure. The matrix-decomposition-based identification results of array signal parameters provide a necessary condition for the effectiveness of parameter estimation algorithms. They are independent of specific parameter estimation algorithm, but only depend on the structure property of array manifold and signals. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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New Adaptive Threshold Filtering for Fiber Optic Gyroscopes LIU Ying1;2, LI Yan1, XU Jin-tao2 Journal of Applied Sciences    2010, 28 (1): 56-59.   Abstract （1848）      PDF（pc） （643KB）（1593）       Knowledge map    Save Through Lipschitz index analyzsis of changes in wavelet factor of the signal and noise in different discrete scales, the signal model of fiber optic gyroscope (FOG) is established. Based on the discrete wavelet transform, a new adaptive filtering algorithm is studied. This algorithm can automatically adjust the threshold values of the wavelet coefficients at different scales in accordance with the energy level of FOG’s output signal. Thus, a new threshold function is obtained, which weakens wavelet coefficients lower than the threshold and maximally reserves the true signal using a multinomial. Compared with the soft and hard threshold function, the new threshold function shows perfect performance with different SNR. Simulation shows that, compared with traditional fixed threshold wave filtering, the new method can effectively eliminate noise, and improve FOG’s bias stability, random walking and other technique parameters. Related Articles | Metrics | Comments（0）

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Multi-resolution Approach to Periodicity Detection Based on Wavelet Transform XU Zhan-yang1;2, Charles ZHAN3, ZHANG Shun-yi1 Journal of Applied Sciences    2010, 28 (1): 60-64.   Abstract （1752）      PDF（pc） （639KB）（1452）       Knowledge map    Save In this paper, we present a novel approach of periodicity detection using wavelet technology.Adaptive wavelet denoising is applied to the PV data. The redundant dyadic discrete wavelet transform is used to decompose the PV oscillation and detect the extreme wavelet coefficients which used to reconstruct the PV signal to avoid signal distortion at different resolution scales. Calculating the indexes based on the post-processing of extreme coefficients, periodicity at the scales selected is worked out, and the PV oscillation periodicity can be obtained. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Small-Area Implementation of RSA Encryption Engine LIU Zheng-lin, GUO Wen-ping, HUO Wen-jie, ZOU Xue-cheng Journal of Applied Sciences    2010, 28 (1): 65-71.   Abstract （1636）      PDF（pc） （613KB）（2529）       Knowledge map    Save Due to the complexity of the popular asymmetric-key encryption algorithm RSA, the hardware implementation has a too large overhead to be used in resource-constrained systems. In order to solve this problem, an RSA encryption engine based on 256 bit data width processor is designed, which greatly reduces the area required by RSA. Synthesis results show that, in addition to the basic function implementation, the improved RSA design reduces the area by 55.63% with respect to SLE66CX160S of Siemens. It has 24 k gates count with a maximum clock frequency of 100 MHz. The implemented RSA engine meets the design requirements. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Self-Organizing Fuzzy Neural Network-Based Actuator Fault Estimation for Satellite Attitude Systems CHENG Yue-hua1;2, JIANG Bin1, YANG Ming-kai1, GAO Zhi-feng1 Journal of Applied Sciences    2010, 28 (1): 72-76.   Abstract （1890）      PDF（pc） （608KB）（1536）       Knowledge map    Save Weights and nodes of a self-organizing fuzzy neural network (SOFNN) can be updated online for network structure optimization. This paper studies a robust fault diagnostic approach based on two SOFNNs for a class of satellite attitude dynamics. The designed SOFNN1 is used to estimate uncertainties and external perturbations of fault-free satellite attitude dynamics, whose output is chosen as a referenced threshold of fault detection. Based on SOFNN1, SOFNN2 is constructed to estimate actuator faults occurring in the satellite attitude dynamics. Simulation results demonstrate that SOFNN has good dynamics performance in estimating actuator faults for the considered dynamics with external noise and system parameter uncertainties. Compared with fixed-structured FNN, the proposed SOFNN has advantages in estimation speed. Related Articles | Metrics | Comments（0） Cited: Baidu(8)

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Lateral Reference Trajectory Planning of Terminal Area Energy Management for Reusable Launch Vehicles ZHANG Jun, HUANG Yi-min, YANG Yi-dong Journal of Applied Sciences    2010, 28 (1): 77-82.   Abstract （1645）      PDF（pc） （1133KB）（1534）       Knowledge map    Save Abstract: According to the initial position of reusable launch vehicles (RLV) in terminal area energy management (TAEM), the lateral reference trajectory is planned to erase the initial position errors using the SNAKE algorithm. The course of lateral reference trajectory planning can be divided into two phases: erasing the lateral position error and erasing the longitudinal error. In the former phase, the longitudinal error is decreased. For erasing the longitudinal error, we propose to erase the error by proper trajectory mode according to its size. The lateral trajectory planning algorithm provides a kernel algorithm for 3-D TAEM trajectory generation which is a basis of onboard trajectory generation of RLVs’ TAEM guidance. Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Improved Multi-objective Genetic Algorithm with Application to PID Optimization Design LIU Nan-nan1, SHI Yu1, CHENG Wei-ping2, QIN Fu-gao3;4 Journal of Applied Sciences    2010, 28 (1): 83-89.   Abstract （2089）      PDF（pc） （692KB）（1797）       Knowledge map    Save We propose a multi-objective optimization genetic algorithm, which uses a new method to calculate crowding distance and improves the comparative method of non-domination. Double elitism-mechanism is introduced to improve efficiency of evolution and solution quality, and more effectively increase diversity of the solution. The algorithm is applied to optimal design of PID. In this way, the system is capable of considering requirements for quickness, reliability and robustness. A satisfactory solution is selected in Pareto optimum set according to the requirements of the present system. Simulation results indicate effectiveness of the proposed algorithm. Related Articles | Metrics | Comments（0） Cited: Baidu(9)

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Large Travel Range Nanopositioning Actuation without Overshooting for Tubular Permanent Magnet Synchronous Linear Motor XU Cong-yu, YU Xiao-fen, CHENG Ling-li Journal of Applied Sciences    2010, 28 (1): 90-94.   Abstract （1710）      PDF（pc） （1042KB）（1657）       Knowledge map    Save Abstract: To reduce electromagnetic disturbance of nanopositioning caused by direct actuation of cylindrical permanent magnet synchronous linear motor (TPMSLM), the actuation mode of rotor and stator’s eccentric installation of TPMSLM is studied. The actuation mode changes the interior space magnetic field distribution of TPMSLM, therefore the axial electromagnetic force containing electromagnetic disturbance is decreased and the radial electromagnetic force containing electromagnetic disturbance is produced. When guide damping is added, a large amount of electromagnetic disturbance can be absorbed. Further more, to prevent large positioning overshooting, a PI control algorithm with variable coefficients is studied, which changes dynamical and static actuation characteristics of system in real-time to supply optimal control parameters for large travel range actuation and nanopositioning actuation. Experimental results indicate that, using the eccentric actuation mode and variable coefficient PI control algorithm, large travel range positioning actuation without overshooting and accurate positioning with errors less than 10 nm are achieved. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Suppression of Wing Rock with Adaptive Neural Control YUAN Suo-zhong Journal of Applied Sciences    2010, 28 (1): 95-98.   Abstract （2049）      PDF（pc） （576KB）（1718）       Knowledge map    Save We propose to control the nonlinear wing rock motion of fighter aircraft using an adaptive nonlinear control strategy based on neural networks. An approximate dynamic inversion method is used to linearize the dynamics of wing rock. A linear controller is designed to stabilize the error dynamics. An adaptive neural network is used to cancel the inversion error. Simulation results of a slender delta wing combat aircraft model at different angle of attack show that the control design can effectively suppress wing rock. Related Articles | Metrics | Comments（0）

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Two-Step Fusion Algorithm for ADS/INS Angles of Attack on Transonic Flight LI Rui-jia, LI Rong-bing, LIU Jian-ye, MENG Bo Journal of Applied Sciences    2010, 28 (1): 99-105.   Abstract （2093）      PDF（pc） （914KB）（1685）       Knowledge map    Save The angle of attack (AOA) is an important state parameter of flight. It is also a necessary parameter in flight control and navigation systems. The modern fighters have increasing demands on the AOA accuracy. The performance of air data systems (ADS) seriously declines under transonic conditions. The accuracy of ADS-AOA is seriously affected. In view of air data sensor configuration features of testing plane, a transonic ADS-INS AOA two-step fusion algorithm based on variable parameters complementary filter and neural network is designed in this paper to achieve fusion of INS and ADS. The divergent transonic INS vertical velocity is resolved. Variable parameters complementary filter and neural network are used to fuse and correct ADS-INS AOA. The result approaches the true AOA with stability and reliability. Actual flight data are used to validate the two-step fusion algorithm. The results show that the AOA after fusion and correction can eliminate violent fluctuations of ADS-AOA under transonic condition. Its tendency coincides with the true AOA with small error. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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MRF Locking Damper for Micrometer/Nanometer Measurement MA Wen-ping, YU Xiao-fen, CHENG Ling-li, YU Qing Journal of Applied Sciences    2010, 28 (1): 106-110.   Abstract （1822）      PDF（pc） （785KB）（1767）       Knowledge map    Save A locking damper based on the new functional materials, magnetorheological fluids, is studied. It can reduce vibration of driving motor and make a micro-impact locking for the working table. The magnetic circuit is simulated with finite element analysis and the property is calibrated using a reciprocating experimental system. It is used in Nano-CMM for nano-positioning experiments, showing that positioning steady-state fluctuation of the working table is reduced from 20 nm to less than 5 nm when the MRF locking damper is used. It ensures the nano-degree positioning steady-state fluctuation in Nano-CMM. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Recognition of Communication Signals in Noise with Alpha Stable Distribution YANG Wei-chao, ZHAO Chun-hui, CHENG Bao-zhi Journal of Applied Sciences    2010, 28 (2): 111-114.   Abstract （2613）      PDF（pc） （546KB）（2256）       Knowledge map    Save Alpha stable distribution is a limiting distribution that maintains the generating mechanism and spreading condition of natural noise. We study the fractal box dimension characteristics of alpha stable distribution and show that, in theory, the fractal box dimension is insensitive to alpha stable distribution with a characteristic index between 1 and 2. We select the fractal box dimensions of signal phase as the recognition characteristic parameter to complete signal recognition. Theoretical study and numerical simulation show that the method has good robustness in background noise with alpha stable distribution. Related Articles | Metrics | Comments（0） Cited: Baidu(16)

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Sliding Mode Adaptive Synchronization Control of Hyperchaotic System and Its Application in Secure Communication MEI Rong,WU Qing-xian, JIANG Chang-sheng Journal of Applied Sciences    2010, 28 (2): 115-122.   Abstract （2531）      PDF（pc） （824KB）（1685）       Knowledge map    Save Due to their intrinsic randomness, sensitivity to initial values and broadband spectrum, chaotic systems have been used to implement secure communication. To improve security and enhance anti-interference ability, a four-dimensional hyperchaotic system with unknown parameter is designed based on the classical Lorenz chaotic system. A single signal control is proposed based on sliding mode adaptive control to synchronize hyperchaotic systems with the same structure. When synchronization is achieved, the hidden signal can be restored effectively at the receiving end. Numeric simulation shows effectiveness of the proposed technique. Related Articles | Metrics | Comments（0）

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Wireless Handoff Scheme in IEEE802.11 MAC Layer for High-Speed Mobile Communications ZHAO Li-fang, CHEN Bing Journal of Applied Sciences    2010, 28 (2): 123-128.   Abstract （3174）      PDF（pc） （1192KB）（6320）       Knowledge map    Save Mobile station performs a handoff when it moves out of the range of one access point and tries to connect to the next. The delay and lost packets caused by the handoff process affect the network quality of service. Taking subway wireless communication system as an application scenario, the number of channels used is reduced, which decreases the scan delay effectively. An algorithm called Layer2-Buff is proposed to solve the problem of lost packets, which sets up buffers for STA, and used to save data that cannot be sent successfully. Test results show that Layer2-Buff reduces the packet loss rate to zero in an automatic train control system, and extra delay to the network is tolerable. This algorithm has been applied to a pre-research project of subway signal systems. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Performance of Online Blind Separation of Dynamically Segmented Mixed Acoustic Signal for CVR YANG Lin, WANG Cong-qing, ZHANG Hong-zhan Journal of Applied Sciences    2010, 28 (2): 129-135.   Abstract （2458）      PDF（pc） （998KB）（1588）       Knowledge map    Save Considering the existence of slight time-varying characteristics and a large number of near-zero signal values, we propose an online blind separation algorithm based on signal sample dynamic segmentation. The online algorithm of independent component analysis (ICA) is used to achieve dynamic segmentation. The FastICA algorithm is executed until converging to an optimal solution. To obtain better performance, weights of the rows in the separation matrix are adjusted. Simulation results show excellent performance of the proposed algorithm, indicating that the algorithm can effectively separate mixed acoustic signals recorded by CVR. Related Articles | Metrics | Comments（0）

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Detection and Compensation of Shadows in High Resolution Remote Sensing Images Using PCA Journal of Applied Sciences    2010, 28 (2): 136-141.   Abstract （2694）      PDF（pc） （1283KB）（2011）       Knowledge map    Save From the shadow region properties, a new algorithm of shadow detection and compensation based on principal component analysis (PCA) is proposed for high resolution remote sensing images. The ratio between the original blue band and the first principal component is computed. Shadow and non-shadow regions are segmented using the histogram-thresholding method. A morphological algorithm is used to produce an accurate shadow mask, and a dilation operation is performed to find the surrounding homogeneous region of a shadow. Each shadow region is matched to its adjacent homogeneous region to achieve shadow compensation. Finally,image smoothing and inverse PCA transformation are performed on the compensated image. Experimental results show that the algorithm is effective. Related Articles | Metrics | Comments（0） Cited: Baidu(24)

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Audio Tampering Detection Based on Band-Partitioning Spectral Smoothness DING Qi, PING Xi-jian Journal of Applied Sciences    2010, 28 (2): 142-146.   Abstract （2888）      PDF（pc） （614KB）（2517）       Knowledge map    Save To detect resampling in audio tampering, a new spectral measure, band-partitioning spectral smoothness (BPSS), is proposed to measure the degree of spectral fluctuation. Based on the analysis to spectral characteristics of non-interpolated and interpolated audio signals, a comprehensive strategy to detect audio interpolation and stitching with BPSS is presented. Experiment results show that, by using the proposed method, it can be correctly determined whether the audio signals are interpolated or stitched. Furthermore, the original sampling rates of the interpolated signals can be estimated with high accuracy. Low computational complexity enables this method to be useful in real time audio tampering detection. Related Articles | Metrics | Comments（0） Cited: Baidu(22)

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Red Tide MODIS Monitoring Based on Multi-oceanic Parameters XUE Cun-jin, DONG Qing Journal of Applied Sciences    2010, 28 (2): 147-151.   Abstract （2365）      PDF（pc） （1056KB）（1948）       Knowledge map    Save Taking into account the drawbacks in the red tide extraction from single oceanic parameter, this paper presents a new red tide monitoring technique using multiple oceanic parameters. The method focuses on the sea surface temperature and chlorophyll-a concentration retrieved from MODIS imagery. In combination with suspended sediment concentration and sea water abnormalities, we have designed the discrimination rules, which take full advantages of each oceanic parameter to extract red tides, and avoid missing and erroneous information obtained based on a single parameter. MODIS imageries acquired on May 30 and June 11, 2004, covering the Bohai Sea, are taken as an example to show validity and feasibility of the proposed method. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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Acoustic Model of Noise Prediction and Algorithm for Capacitor Tower in DC Converter Station WEI Hao-zheng, LI Zhi-yuan, LI Xiao-lin, HUANG Ying, RUAN Xue-yun Journal of Applied Sciences    2010, 28 (2): 152-157.   Abstract （2427）      PDF（pc） （12994KB）（1534）       Knowledge map    Save According to the noise property of capacitor tower in DC converter station, we compare the algorithms for vertical linear acoustic sources, and propose an improved method of optimal division of vertical linear acoustic sources alone. The method chooses a proper value of the division length by comparison. An algorithm is developed  based on the proposed method, giving better accuracy of noise attenuation prediction of capacitor tower and more reasonable results than a commercial software product. Related Articles | Metrics | Comments（0）

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Demodulation of Touch Trigger Probe Based on FBG with Experimental Study DING Bang-zhou, FEI Ye-tai, FAN Zhe-guang Journal of Applied Sciences    2010, 28 (2): 158-162.   Abstract （2379）      PDF（pc） （4209KB）（1781）       Knowledge map    Save The touch trigger probe based on fiber Bragg gratings is a newly developed probe. With a sensing element used in a three-dimensional probe, sensor signal demodulation is a key technique. By means of the dual-frequency laser interferometer and nano-level stage, the sampling probe is tested using a self-demodulation approach based on the functional relations between optical power and wavelength shift. Resolution of more than 100 nm can be achieved from the analysis of experimental data on a developed probe. Furthermore, experiments verify that application of FBG sensors in a three-dimensional probe is feasible. Related Articles | Metrics | Comments（0）

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Video Restoration Using Exemplar-Based Inpainting GU Yi, HAN Jun Journal of Applied Sciences    2010, 28 (2): 163-169.   Abstract （2380）      PDF（pc） （2667KB）（1924）       Knowledge map    Save  This paper applies exemplar-based image inpainting to video restoration, and improves the repairing method by using time correlation characteristic of video sequences. The new method of video damage restoration can repair damages which are difficult to be detected in videos. Experiments show that, comparing with exemplar-based image inpainting, the method is more efficient in video restoration, can avoid filling errors and error spread, and has better efficiency. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Calculation of 2D Site Percolation Parameters of Electrical Conductivity Using Renormalization Group Method HE Chao, Lü Xu-liang, GAO Fu-yin JIA Qi Journal of Applied Sciences    2010, 28 (2): 170-174.   Abstract （2491）      PDF（pc） （675KB）（1815）       Knowledge map    Save The renormalization group method is an effective way to calculate percolation parameters of conducting polymer composites. Percolation parameters of the 8-neighbor rule and the 4-neighbor rule are calculated by renormalization group in different correlation dimensions. The results show that more accurate parameters can be obtained by raising the value of correlation dimension M. The fractal dimension of infinite percolation cluster is reduced because of the increase of critical exponent. The 8-neighbor rule is to some degree more appropriate to demonstrate the percolation model of electrical conductivity because its percolation threshold is close to the experimental results. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Energy-Oriented Dynamic SPM Allocation Based on Time-Slotted Cache Conflict Graph WANG Huan, LING Ming, ZHANG Yang, MEI Chen Journal of Applied Sciences    2010, 28 (2): 175-181.   Abstract （2270）      PDF（pc） （1378KB）（1854）       Knowledge map    Save In this paper, an allocation strategy is proposed to optimize energy of memory system. A timeslotted cache conflict graph is proposed to model the behavior of data cache conflict. An integer nonlinear programming (INP) is implemented, which can avoid time-consuming linearization process, to select the most profitable data pages and employ a virtual memory system to remap those data pages that can cause severe cache conflict within a time slot, to the on-chip scratchpad memory (SPM). To minimize the swapping overhead of dynamic SPM allocation, we introduce a novel SPM controller with a tightly coupled DMA to issue the swapping operations without CPU intervention. The proposed method can optimize all data segments including global data, heap and stack data in general, and reduce the total energy consumption by 24.83% on average without any performance degradation. Related Articles | Metrics | Comments（0）

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Improved Ant Colony Optimization Algorithm for Job Shop Scheduling Problem ZHANG Zhi-qiang, ZHANG Jing, ZHANG Xiang, LI Shu-juan Journal of Applied Sciences    2010, 28 (2): 182-188.   Abstract （2338）      PDF（pc） （532KB）（1863）       Knowledge map    Save An improved ant colony optimization algorithm for job shop scheduling problems is proposed in this paper. The tabu list which can generate active schedule is designed. The traditional ant colony optimization algorithm is hen simplified, and a new priority rule proposed to serve as heuristic information. A local search procedure based on the neighborhood structure of job shop scheduling problem is introduced to improve convergence and solution quality of the proposed algorithm. Experiments show effectiveness of the proposed algorithm. Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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Design of Dynamic Output Feedback Controller for Lurie Networked Control Systems JIANG Bing, ZHANG Chong-wei Journal of Applied Sciences    2010, 28 (2): 189-196.   Abstract （2484）      PDF（pc） （683KB）（2092）       Knowledge map    Save Taking into consideration network-induced delay, data packet dropout and data packet disorder, the Lurie networked control system is modeled as a multiple delay Lurie system. A delay-dependent stability condition is established via free weighting matrices. Based on an equation constraint, it is transformed into a solvability problem described by linear matrix inequality. The dynamic output feedback control law is then presented. Two numerical examples show feasibility and effectiveness of the design method. Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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Optimal Control of Structure Seismic Response Using Linear Quadratic Performance Function and Iterative Learning WANG Jian-guo, WANG Quan, ZHANG Ming-xiang Journal of Applied Sciences    2010, 28 (2): 197-202.   Abstract （2313）      PDF（pc） （640KB）（1765）       Knowledge map    Save By combining linear quadratic optimal control and iterative learning control (ILC), a new hybrid control strategy named linear quadratic optimal iterative learning control is obtained. The optimal control force is determined according to quadratic performance function minimization in the process of ILC to reduce the earthquake displacement response of engineering structures. Effectiveness of the control is studied. The model of a typical seismically excited building in the second generation benchmark vibration control for buildings is studied using the new hybrid control strategy to calculate seismic displacement response of the building. Simulation results show that the new control strategy can effectively control earthquake displacement response with improved effectiveness. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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Adaptive Pinning Synchronization for Complex Network Coupled with the Outputs FAN Chun-xia, JIANG Guo-ping Journal of Applied Sciences    2010, 28 (2): 203-208.   Abstract （2366）      PDF（pc） （1283KB）（1815）       Knowledge map    Save An adaptive pinning control method is proposed for synchronization of a complex network coupled with output. Unlike existing synchrnization methods, output of a complex network is used to construct synchronization controllers, and the synchronization-controller gains are adapted according to synchronization errors, and only part of nodes need to be controlled in the complex network. Furthermore, synchronization criteria are achieved for a complex network on the basis of the Lyapunov stability theory. Numerical simulations are carried out for a small-world network and a scale-free network, the results showing effectiveness of the proposed scheme for synchronization of complex network. Related Articles | Metrics | Comments（0） Cited: Baidu(14)

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Satellite Formation Fly Control Based on Atmospheric Drag CHEN Zhi-ming, WANG Hui-nan, LIU Hai-ying Journal of Applied Sciences    2010, 28 (2): 209-215.   Abstract （2378）      PDF（pc） （1815KB）（1841）       Knowledge map    Save A new control method is described using atmospheric drag. It was based on the traditional control method of  satellite formation flying. Besides, the system configuration and control law are given. With drag panels, fuel is no longer a limitation to the satellite service life. This method is useful both in attitude control and formation control problems. It can reduce system complexity and enhance function density, and therefore has a good application prospect. Simulation results show that the method is effective in terms of the expected control efficiency. Related Articles | Metrics | Comments（0）

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Control of Ascending Flight of Reusable Launch Vehicles HE Cheng-long, CHEN Xin, WU Liao-ni Journal of Applied Sciences    2010, 28 (2): 216-220.   Abstract （2449）      PDF（pc） （649KB）（1694）       Knowledge map    Save As the initial flight phase of reusable launch vehicle (RLV), the ascending phase has its special characteristics, that is, fast changes during flight in the gravity center, the atmospheric density and the motion state. The control law should suit the fine stability and maneuverability in the whole flight envelope to make analysis easy. The entire flight is divided into four phases in this paper: drop, ignition, powered climb and unpowered climb. Different control strategies are used according to the characteristic of each phase. Trajectory linearization control (TLC) is involved for advanced nonlinear tracking and robust control, and the forward control and feedback control law are designed. Nonlinear simulation shows that the control scheme satisfies the ascent control requirements. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Admission Control Strategy for Multi-priority Traffic in MANET Based on Flexible QoS LIU Chao, HU Ai-qun Journal of Applied Sciences    2010, 28 (3): 221-228.   Abstract （2049）      PDF（pc） （779KB）（1769）       Knowledge map    Save To conform to the property of priority differentiation and meet the dynamic resource requirement for multimedia traffics, a dynamic resource allocation and optimization strategy based flexible admission control is presented. A new bandwidth adjustment rule, a path bandwidth calculation algorithm and a QoS routing protocol that meets dynamic resource requirements are designed to support applications of the scheme in the multi-hop network environments. Simulation results show that the proposed scheme has low probabilities of new connection blocking and handoff connection dropping, and more traffic flows can be admitted. It supports differentiated services for flows with different priorities, and thus can achieve better share, balance and utilization for wireless resources as compared to conventional ones. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Modeling and Analysis of Asynchronous Backoff Phenomena in IEEE 802.11 Distributed Coordination Function WU Qi-lin, LU Yang, NI Pu, GE Lun-yue Journal of Applied Sciences    2010, 28 (3): 229-236.   Abstract （2326）      PDF（pc） （686KB）（2630）       Knowledge map    Save In single-hop wireless local area networks based on the IEEE 802.11 distributed coordination function (DCF) protocol, packet collisions can cause asynchronous backoff among nodes. To analyze the effect of this phenomenon on the throughput of IEEE 802.11 DCF, this paper proposes a new analytic model of three-dimensional Markov chain, in which the unit-time of state transitions have a fixed length equal to the physical-layer slot. The sate transitions of freezing duration are considered. Simulations show that the analytic model is accurate for the two mechanisms of packet transmission employed by IEEE 802.11 DCF, and can lead to better correctness than the referenced model as the number of nodes increases. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Trustworthy Global Reputation Model in Peer-to-Peer Networks WANG Kun, WU Meng Journal of Applied Sciences    2010, 28 (3): 237-245.   Abstract （2038）      PDF（pc） （686KB）（2231）       Knowledge map    Save In terms of the nodes security issues in peer-to-peer networks, we present a global reputation model that dynamically updates the service trust value and requests trust value according to the transaction history. We also discuss the impact of five types of attacks on the reputation model in establishing the secure reputation model. Simulation results show that the trust updating algorithms and defense mechanisms of this model provide a high degree of robustness. Meanwhile, the reputation model can effectively protect honest nodes, reduce the trust value of malicious nodes, and restrain malicious behaviors. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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