2014 Vol.32

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Resource Allocation for Capacity-Maximization in SC-FDMA Relay Systems ZHU Yu, ZHANG Meng-ying Journal of Applied Sciences    2014, 32 (1): 1-6.   DOI: 10.3969/j.issn.0255-8297.2014.01.001 Abstract （2229）      PDF（pc） （1231KB）（978）       Knowledge map    Save  Resource allocation algorithms are proposed to maximize the capacity of single carrier frequency division multiple access (SC-FDMA) relay systems. Taking into account the subchannel adjacency restriction of SC-FDMA, an optimal algorithm is presented to reformulate this problem as a set partitioning problem. By using the relevant methods in operations research, the optimal solution can be obtained. A suboptimal algorithm based on the greedy heuristic thinking is also proposed to reduce computational complexity of the optimal resource allocation. Simulation results show that, in amplify-and-forward and decode-and-forward relay-assisted SC-FDMA systems, spectral efficiency of the optimal algorithm is much higher than that of the random algorithm. The greedy algorithm with much lower complexity performs quite close to the optimal algorithm. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Journal of Applied Sciences    2014, 32 (1): 1-1.   Abstract （494）      PDF（pc） （423KB）（783）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2014, 32 (1): 1-.   Abstract （478）      PDF（pc） （63KB）（731）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Coding-Aware Routing by Fully Considering Coding Opportunity ZHAO Yun-long1, WANG Bo-shi1, ZHANG Kai1, DONG Zhao1, ZHANG Lei2 Journal of Applied Sciences    2014, 32 (1): 7-12.   DOI: 10.3969/j.issn.0255-8297.2014.01.002 Abstract （1405）      PDF（pc） （5434KB）（1261）       Knowledge map    Save A key in applying networking coding techniques in wireless networks is to explore more coding opportunities. A maximal coding opportunity discovery scheme is proposed, and by combining it with existing coding-aware routing protocols, a coding-aware routing protocol termed extended coding aware routing (Ex-CAR) is presented. The protocol takes maximal coding opportunity into consideration and selects the coding node number as a metric to determine the best forwarding node along the optimal route. Simulation experiments in NS-2 show that the proposed algorithm is effective, and ExCAR can enhance the network throughput and improve packet delivery rate. Reference | Related Articles | Metrics | Comments（0）

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QoS Guarantee for Mixed-Service in OFDM Relay System DAI Cui-qin, WANG Liang, WANG Hai-bao Journal of Applied Sciences    2014, 32 (1): 13-18.   DOI: 10.3969/j.issn.0255-8297.2014.01.003 Abstract （1814）      PDF（pc） （4644KB）（1230）       Knowledge map    Save  To ensure QoS requirements for mixed-service in an orthogonal frequency division multiplexing relay system, we propose a relative largest queue aware first/relative proportional fair (R-LQAF/RPF) scheduling algorithm. By setting a relative variation function, we use an RPF scheduling algorithm to enhance the realtime user throughput to meet the actual user rate requirements. We also use an R-LQAF scheduling algorithm to improve the scheduling performance, decrease the packet loss rate, and ensure QoS requirements for non-realtime user according to the relationship of the user queue length and the system queue length.Simulation results show that, compared with the existing proportional fair and the largest weighted delay first algorithm, the R-LQAF/RPF algorithm can flexibly choose different scheduling strategies for different businesses, effectively improve user performances in terms of throughput, packet loss rate, and satisfaction of demanded rate, and guarantee QoS requirements of mixed businesses. Reference | Related Articles | Metrics | Comments（0）

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Quantum-Inspired Shuffled Frog Leaping Algorithm for Spectrum Allocation in Cognitive Radio GAO Hong-yuan1, CAO Jin-long2 Journal of Applied Sciences    2014, 32 (1): 19-26.   DOI: 10.3969/j.issn.0255-8297.2014.01.004 Abstract （2003）      PDF（pc） （6454KB）（1367）       Knowledge map    Save To solve a discrete optimization problem, a quantum-inspired shuffled frog leaping (QSFL) algorithm based on shuffled frog leaping algorithm and quantum information theory is proposed. The QSFL algorithm uses quantum movement equations to find the optimal location by the co-evolution of quantum frog colony. Good performance of the QSFL algorithm is shown by some classical benchmark functions. At the same time, we design an assignment method for cognitive radio spectrum allocation without interference based on it. Simulations are conducted to compare this method with genetic algorithm (GA), quantum genetic algorithm (QGA), particle swarm optimization (PSO), shuffled frog leaping algorithm (SFLA) and color-sensitive graph coloring (CSGC) using different network utility functions. Simulation results indicate that the proposed method can find the near-optimal solution. It outperforms the color-sensitive graph coloring and the previous intelligent spectrum allocation methods. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Multi-user Two-Way Relay Power Control for CDMA System ZHANG Er-wei, QIU Ling Journal of Applied Sciences    2014, 32 (1): 27-31.   DOI: 10.3969/j.issn.0255-8297.2014.01.005 Abstract （1967）      PDF（pc） （6401KB）（1311）       Knowledge map    Save For multi-user two-way relay in CDMA systems, bit error rate (BER) of the first jump is approximated,an efficient function of power control obtained, and an iterative algorithm for power control provided.Exsitence and uniqueness of Nash equilibrium is proved theoretically. Simulation results show reliability, fast convergence, and low power of convergence of the proposed approximation. Compared to traditonal algotithms,the proposed method can reduce the average transmit power with large number of users in the system. Reference | Related Articles | Metrics | Comments（0）

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Optimized Interleaver for Protograph LDPC Coded BICM with High Spectral Efficiency DOU Jin-fang1, HE Shan-bao2, JIANG Ming3 Journal of Applied Sciences    2014, 32 (1): 32-38.   DOI: 10.3969/j.issn.0255-8297.2014.01.006 Abstract （1794）      PDF（pc） （2389KB）（1383）       Knowledge map    Save As a crucial part in bit-interleavered coded modulation (BICM), protograph low-density paritycheck(P-LDPC) codes and interleavers can greatly improve the performance of a BICM system. In this paper, we use a modified EXIT analysis method to analyze thresholds for a P-LDPC coded BICM system with high-order QAM in different variable degree matched mapping (VDMM) schemes. A general criterion for optimization of VDMM interleavers is proposed. Results of numerical analysis and simulation show correctness of the optimization criterion. Reference | Related Articles | Metrics | Comments（0）

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Polarization Dependent Loss in Coherent Optical Systems HAO Yao-hong1, LENG Dan1, FANG Tao2 Journal of Applied Sciences    2014, 32 (1): 39-43.   DOI: 10.3969/j.issn.0255-8297.2014.01.007 Abstract （1893）      PDF（pc） （7900KB）（1399）       Knowledge map    Save Coherent optical OFDM system (CO-OFDM) is a promising technology in high speed long-haul optical transmission. Polarization dependent loss (PDL) and first-order polarization mode dispersion (PMD) influence system performance seriously in high speed transmission. The mathematical model of transmission is analyzed, and a signal equalization scheme is proposed for CO-OFDM systems. Numerical simulation is done to validate the method and the estimation algorithm. Analysis and simulation results show that the polarization effect may cause amplitude noise and phase noise, which can be eliminated with signal equalization. At a length of 720 km, the Q value is improved by 0.8 dB for = 1 compared with = 0.5. Meanwhile, the first-order PMD may reduce the PDL effect by rotation of SOP (state of polarization). Reference | Related Articles | Metrics | Comments（0）

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Effects of Forgetting Factor on RLS Dictionary Learning   YU Fu-ping1,2, FENG You-qian1, LEI Teng1, LI Zhe1 Journal of Applied Sciences    2014, 32 (1): 44-50.   DOI: 10.3969/j.issn.0255-8297.2014.01.008 Abstract （2472）      PDF（pc） （12752KB）（1082）       Knowledge map    Save Dictionary learning is a hot topic in signal sparse decomposition. The choice of the initial dictionary affects the result of dictionary learning. In order to reduce the effects, a forgetting factor is introduced into the recursive least squares (RLS) dictionary learning. The dictionary learning effects of three dictionary learning methods, method of optimal directions (MOD), K singular value decomposition (KSVD), and RLS are compared. Influences of different fixed forgetting factors on the final learned dictionary are analyzed,and the results of dictionary learning with different forgetting factors studied. Simulation shows that the RLS dictionary learning reduces the influence of the initial dictionary, and gives better effects. Results of the dictionary learning are influenced by the choice of the forgetting factor. Reference | Related Articles | Metrics | Comments（0）

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Design of Directional Modulation Signal Based on Multi-objective Genetic Algorithm for Physical Layer Secure Communication HONG Tao1, SONG Mao-zhong2, LIU Yu2 Journal of Applied Sciences    2014, 32 (1): 51-56.   DOI: 10.3969/j.issn.0255-8297.2014.01.009 Abstract （2055）      PDF（pc） （3672KB）（1098）       Knowledge map    Save A directional modulation signal based on multi-objective genetic algorithm is proposed. According to the relationship between Euclidean distance of constellation points and bit error rate performance, the phase shift values are generated by means of optimizing multi-objective genetic algorithm to synthesize a directional modulation signal. This signal transmits different signal constellation at different directions. In the desired direction, the signal’s constellation is the same as the traditional baseband modulation signal while the constellation is scrambled in other directions. Compared with the traditional directional modulation signal, the proposed directional modulation signal has a narrower beam-width. Simulation results show that the technique offer a better physical layer secure transmission signal for wireless communication. Reference | Related Articles | Metrics | Comments（0）

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Multi-dimensional Angle Estimation in Bistatic MIMO Radar for L-Shaped Array with Propagator Method SUN Zhong-wei, ZHANG Xiao-fei, WU Hai-lang, LI Jian-feng Journal of Applied Sciences    2014, 32 (1): 57-64.   DOI: 10.3969/j.issn.0255-8297.2014.01.010 Abstract （1778）      PDF（pc） （2547KB）（1035）       Knowledge map    Save  Computation complexity of spatial spectrum estimation algorithm is high. To solve this problem,a PM algorithm is introduced for estimation of 2D direction of departure (DOD) and 2D direction of arrival (DOA) for bistatic MIMO radar. A propagator is estimated using the cross correlation matrix. By rotationinvariance of the propagator, one can estimate the direction of the matrix, and further estimate DOD and DOA. The algorithm has low computation complexity, and can achieve multi-dimensional automatic pairing. With similar angles, good performance is still maintained. In the case of high SNR, performance of the proposed algorithm is close to that of the ESPRIT. Mean square error of angle estimation is derived. Simulation results verify the usefulness of the algorithm. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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Image Self-Embedding Based on EZW Coding and Fountain Codes LIAO Chun, QIAN Zhen-xing, NI Jing, WANG Shuo-zhong Journal of Applied Sciences    2014, 32 (1): 65-73.   DOI: 10.3969/j.issn.0255-8297.2014.01.011 Abstract （2193）      PDF（pc） （14781KB）（4410）       Knowledge map    Save We first utilize EZW to encode the wavelet coefficients of the image, and then the fountain encoding to generate the reference data. By extracting forensic data and reference data which is self-embedded into the image, tampered area is detected and reference data is also reconstructed. Comparing to block-based DCT,we overcome the blocking artifact of the recovered image. Besides this, we propose a method which makes the data embedding and image quality dynamic by adjusting the parameters. A balance between the recovered area and recovered quality is also achievable. Reference | Related Articles | Metrics | Comments（0）

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Frontal Face Synthesis Based on Improved Binocular Stereo Vision WANG Jing1,2, SU Guang-da1 Journal of Applied Sciences    2014, 32 (1): 74-78.   DOI: 10.3969/j.issn.0255-8297.2014.01.012 Abstract （1726）      PDF（pc） （3197KB）（966）       Knowledge map    Save To improve the face recognition performance under different poses, we propose an improved frontal face synthesis method based on binocular stereo vision, which can effectively and quickly synthesize a frontal face. A modified matching algorithm is designed to deal with smoothness of faces. Then 3-D coordinates are generated according to the disparity image, and the pose angle of the face calculated according to the location of eyes. A frontal face is generated according to the pose angle using the method of binocular stereo vision.Experimental results show that the method is precise, practical, and fast. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Generation of Epipolar Images from ZY-3 Satellite Fused Data JIA Yong-hong1,2, ZHU Meng-hua1, DIAO Yong-zhou1, GUAN Yu-juan3 Journal of Applied Sciences    2014, 32 (1): 79-84.   DOI: 10.3969/j.issn.0255-8297.2014.01.013 Abstract （2324）      PDF（pc） （16449KB）（620）       Knowledge map    Save  A high-resolution color epipolar image generation method is proposed based on image fusion. A pair of panchromatic stereo images is fused with registered multispectral images. Approximate epipolar images based on projection reference plane (PRP) are then generated according to the practical epipolarity model for linear pushbroom satellite stereo-imagery. Thus, generation of high-resolution color epipolar images is realized.Experimental results of the ZY-3 data show that the proposed method has the same measurement performance in revealing true terrain features, and can provide more information and better visual interpretation. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Design and Implementation of CUDA Algorithms Based on Nonlinear Image Diffusion LB model ZHOU Ming, YAN Zhuang-zhi, HUANG Bin Journal of Applied Sciences    2014, 32 (1): 85-92.   DOI: 10.3969/j.issn.0255-8297.2014.01.014 Abstract （1782）      PDF（pc） （5381KB）（1247）       Knowledge map    Save  To improve the performance of Lattice Boltzmann (LB) method in image denoising, this paper proposes three compute unified device architecture (CUDA) algorithms to realize streaming processes of LB in nonlinear image diffusion, which are based on texture memory, shared memory, and global memory, respectively.To test effectiveness and efficiency of the GUDA algorithms, experiments were carried out with natural and composite images. The results show that GPU acceleration is 90 times faster than CPU acceleration, and the factor is proportional to the number of GPU stream processors. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Vehicle Identification and Counting Based on Sparse Over-Completeness LU Peng1, LOU Ya-fei1, LIU Feng-zhe2, LI Yu-song1, HUANG Shi-lei1, TANG Yu-he1 Journal of Applied Sciences    2014, 32 (1): 93-98.   DOI: 10.3969/j.issn.0255-8297.2014.01.015 Abstract （1711）      PDF（pc） （6478KB）（1169）       Knowledge map    Save To detect and count high-speed vehicles accurately and robustly, a sparse over-complete model is established to simulate the visual mechanism. The model uses image units as processing objects. It expresses the internal structure and essential attributes of the target image with a small amount of non-zero response sparse coefficients, and identifies different types of vehicles in different environments. Online counting of vehicles is achieved by setting dynamic lanes based on virtual detection lines. Accuracy of the vehicle counting reaches 98.89% under a variety of environmental conditions. The results show that the proposed algorithm can effectively suppress interference caused by external factors such as wind, light changes and camera shakes. It has higher robustness and accuracy than traditional algorithms.   Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Observer Design for a Class of Linear Switched Systems YANG Yin, SUN Wen-an, PEI Bing-nan Journal of Applied Sciences    2014, 32 (1): 99-104.   DOI: 10.3969/j.issn.0255-8297.2014.01.016 Abstract （1655）      PDF（pc） （5870KB）（818）       Knowledge map    Save This paper focuses on the problem of observer design for a class of linear switched systems. By constructing appropriate Lyapunov functions and using matrix inequalities, conditions of the exponential convergence of the estimated state observer are obtained. Furthermore, by using state jump at certain time when the change of value of the switched law occurs and specifying the value of the state jump, the system performance is improved. It is shown that the convergence rate of the estimation error can be reduced significantly. Simulation results are given to show validity of the state observer. Reference | Related Articles | Metrics | Comments（0）

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Inland Waterway Ship Tracking Using a TLD Framework TENG Fei, LIU Qing, GUO Jian-ming, ZHOU Ya-qi Journal of Applied Sciences    2014, 32 (1): 105-110.   DOI: 10.3969/j.issn.0255-8297.2014.01.017 Abstract （1810）      PDF（pc） （6624KB）（1778）       Knowledge map    Save Closed circuit television (CCTV) systems are widely used in the video surveillance of inland waterway. A framework of tracking-learning-detection (TLD) is presented and further enhanced to address the problem of ship identification and tracking in the inland waterway CCTV system. A constraint condition for the eigenvalues is proposed to examine the short-term tracking results so that complexity in calculating normalized cross correlation is avoided. Meanwhile, tracking results for corners in the image are accurately reserved, making the short-term tracking results reliable. Ships can be located accurately by applying cascaded detectors. A template matching method is proposed to ensure accuracy of the algorithm. Extensive experimental results show that the proposed algorithm outperforms the original TLD framework in terms of efficiency, accuracy and robustness. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Opportunistic Interference Alignment with Optimal Capacity in Cognitive Networks AN Yong-li1,2, XIAO Yang1, QU Guang-zhi3 Journal of Applied Sciences    2014, 32 (2): 111-118.   DOI: 10.3969/j.issn.0255-8297.2014.02.001 Abstract （1645）      PDF（pc） （9628KB）（1010）       Knowledge map    Save  Cognitive users can only access idle bandwidth in traditional cognitive networks, but they cannot share the same bandwidth with the primary user simultaneously. In order to make full use of the spectrum, we propose a capacity optimal opportunistic interference alignment algorithm. By ensuring the channel capacity of primary users, cognitive users and primary users can share the same bandwidth, and the cognitive users cause no interference to the primary user. In the proposed algorithm, the hybrid network base station estimates channel state information and calculates channel capacity. It then determines the pre-coding vectors and decoding vectors according to the capacity optimal rule. Cognitive users access the networks by capacity optimal opportunistic interference alignment when the primary user’s channel capacity almost does not decline and the whole network can still obtain good channel capacity. Simulation results show that the proposed algorithm can obtain greater channel capacity and increase the utilization ratio of spectrum than other existing algorithms under the same condition of channel state information. Reference | Related Articles | Metrics | Comments（0）

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Optimal Relay Function and Achievable Secrecy Rate in Orthogonal Relay-Eavesdropper Channel CHEN Chi-yang1,2, DENG Zhi-xiang1, WANG Bao-yun2,3 Journal of Applied Sciences    2014, 32 (2): 119-124.   DOI: 10.3969/j.issn.0255-8297.2014.02.002 Abstract （1639）      PDF（pc） （3816KB）（968）       Knowledge map    Save In this paper, secret communication in an orthogonal relay-eavesdropper channel is studied in view of information-theoretical security. For an orthogonal relay-eavesdropper channel with instantaneous relay in which the present output depends only on the currently received signal, the achievable secrecy rate is formulated. The achievable secrecy rate with piecewise linear(PL) relaying function is derived and computed numerically. A sub-optimal solution to this secrecy rate is obtained by optimizing the parameters of the piecewise linear function with an iterative grid search algorithm. The achievable secrecy rate with PL relaying is compared to that with amplify-and-forward (AF) relaying and decode-and-forward (DF) relaying by simulation. The results show that PL always outperforms AF, and outperforms DF when the source-relay link is poor. Meanwhile, compared with DF, PL relaying has lower complexity and lower time-delay. Reference | Related Articles | Metrics | Comments（0）

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Pipelined RFID Indoor Positioning Based on Locally-Weighted Regression ZHANG Jin-yi1,2,3, ZHANG Jing-jing1, LI Ruo-han1, XU De-zheng2, XU Qin-le2 Journal of Applied Sciences    2014, 32 (2): 125-132.   DOI: 10.3969/j.issn.0255-8297.2014.02.003 Abstract （2137）      PDF（pc） （16751KB）（585）       Knowledge map    Save Radio frequency identification (RFID) is a hot research topic for indoor positioning because it is non-contact and non-line-of-sight with low-cost and high-precision. This paper proposes to use the pipelined packet reception rate as the positioning parameters to enhance stability and improve real-time performance.To deal with the indoor environmental impact on the signal propagation, the pipelined positioning algorithm uses locally weighted regression, which takes full advantage of the indoor environment information to achieve precise positioning. Experimental results show that, for indoor applications, the proposed algorithm increases the positioning accuracy by 56.56% compared with LANDMARK and by 36.73% compared with VIRE. The method can also obtain precise real-time tracking results for multiple targets, showing its practical value and wide range of applications. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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Radar Super-Resolution Imaging Based on Compressive Sensing DENG Zhen-miao, YE Lin-mei, FU Mao-zhong, ZHANG Yi-xiong Journal of Applied Sciences    2014, 32 (2): 133-140.   DOI: 10.3969/j.issn.0255-8297.2014.02.004 Abstract （4927）      PDF（pc） （9134KB）（1975）       Knowledge map    Save Application of compressed sensing (CS) in inverse synthetic aperture radar is investigated in this paper. The radar transmits sparse probing pulses and dechirped radar echo samples that satisfy the Nyquist sampling theorem are resampled sparsely. Reconstruction is performed to these sparse samples both in range and cross-range directions to recover the whole radar echo signals containing the target characteristics. To obtain high resolution ISAR images, super-resolution processing on both range and cross-range directions is conducted on the reconstructed data. Results of processing on real radar data and simulated data show that the resolution of ISAR image can be enhanced significantly. The proposed algorithm can reduce data size and time consumption, and is valuable for super-resolution radar image applications. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Passive Multistatic Radar Imaging Based on Compressed Sensing Joint Sparse Aperture Autofocusing WU Hao, SU Wei-min, GU Hong Journal of Applied Sciences    2014, 32 (2): 141-148.   DOI: 10.3969/j.issn.0255-8297.2014.02.005 Abstract （2149）      PDF（pc） （6403KB）（817）       Knowledge map    Save In this paper, passive multistatic radar imaging based on compressed sensing joint sparse aperture autofocus is presented. The method uses a point spread function of the different opportunistic illuminator to construct a reasonable sparse basis matrix, and turns the point-enhanced problem into an optimization problem by using the lp norm method. Meanwhile an optimization problem in terms of phase error is established. The quasi-Newton method with a phase error update scheme is used to obtain the increment of phase error. The simulation shows good performance of this method at small rotating angle and in the presence of phase error. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Keyword Detection Based on Dynamic Match Lattice Spotting ZHENG Yong-jun, ZHANG Lian-hai Journal of Applied Sciences    2014, 32 (2): 149-155.   DOI: 10.3969/j.issn.0255-8297.2014.02.006 Abstract （1780）      PDF（pc） （4133KB）（1337）       Knowledge map    Save The large amount of speech data requires techniques for rapid and accurate search. This paper proposes a keyword spotting method based on dynamic match Lattice spotting (DMLS). It generates more accurate phone Lattice with TRAP features and multilayer perceptron, and performs a modified Viterbi traversal to compile a database of fixed-length phone sequences in speech indexing. In the searching stage, a minimum edit distance is used as the confidence score to implement the keyword spotting. Tests show that the proposed method is superior to baseline systems with MFCC and PLP features with the recall rate improved by about 5%. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Impact of Random Delays in Control and Measurement Signals on Iterative Learning Control Systems HUANG Li-xun, FANG Yong Journal of Applied Sciences    2014, 32 (2): 156-162.   DOI: 10.3969/j.issn.0255-8297.2014.02.007 Abstract （1644）      PDF（pc） （4350KB）（974）       Knowledge map    Save  Random delays of control and measurement signals during transmission over wireless network seriously affect the convergence performance of iterative learning control (ILC) systems. Based on a one-step random delay model, the transition matrix of system is derived, which contains the impact factors of random delays. For different situations of random delays, variation of eigenvalues and other elements in the lower triangular of transition matrix is analyzed, which determine the convergence speed and robust convergence respectively. Analysis shows that the convergence rate is reduced, and the robust convergence is also affected. Especially, the impact of control signal delays on robust convergence is greater than that of measurement signal delays. Simulation results are provided to demonstrate correctness of the conclusion.   Reference | Related Articles | Metrics | Comments（0）

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Atom Set Calibration and Step Control for Unknown-Sparsity Reconstruction from Compressive Sensing ZENG Chun-yan1,2, MA Li-hong1, DU Ming-hui1 Journal of Applied Sciences    2014, 32 (2): 163-169.   DOI: 10.3969/j.issn.0255-8297.2014.02.008 Abstract （1378）      PDF（pc） （4521KB）（914）       Knowledge map    Save This paper models residual signals with Gaussian-like distributions, based on which consistency between the Backtracking-based adaptive orthogonal matching pursuit (BAOMP) threshold and signal sparselevel is analyzed. An improved BAOMP (IBAOMP) method is thenproposed. Themethod estimates the preliminary matching state usingthe 80-20 rule, and introduces a threshold with variable step size to subtly adjust atom set to raise the correct rate of selected atoms and avoid quasi-periodic mismatches of residual signals. Simulation results of 500 tests show that the exact recovery probability of IBAOMP is 17%-26% higher than BAOMP for Gaussian sparse signals, and more than70% higher than BAOMP for natural images. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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Micro-Doppler Modeling and Signature Extraction of Trucks LI Kai-ming1, ZHANG Qun1,2, LIANG Bi-shuai1, LUO Ying1 Journal of Applied Sciences    2014, 32 (2): 170-177.   DOI: 10.3969/j.issn.0255-8297.2014.02.009 Abstract （1720）      PDF（pc） （13481KB）（633）       Knowledge map    Save  Based on a three-dimensional scatterer model, the echo from a truck is modeled under narrowband chirp signal system. Mathematical representations of the Doppler generated by bulk scatterers and micro-Doppler due to the rotating scatterers on the hub are analyzed and derived. A dictionary is designed in terms of their differences. Meanwhile, a threshold of energy in slow time-range plane is set, which is useful in the extraction of echoes in energy-centralized range cells. Matching pursuit can be implemented by decomposing the echoes into corresponding atoms. Fast extraction of micro-Doppler signature of wheel rotation is accomplished. These provide references for truck recognition. Effectiveness and robustness of the method are shown by the simulation results. Reference | Related Articles | Metrics | Comments（0）

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Self-Embedding Based on Saliency Distribution ZHAO Li-li, QIAN Zhen-xing, HAN Xi-yu Journal of Applied Sciences    2014, 32 (2): 178-184.   DOI: 10.3969/j.issn.0255-8297.2014.02.010 Abstract （1739）      PDF（pc） （8495KB）（634）       Knowledge map    Save  The purpose of image self-embedding is to achieve content authentication and self-recovery by imperceptibly embedding relevant information into the host image. This paper proposes a novel self-embedding method based on significance classification. After classifying the image into three kinds of regions dynamically, the code length and embedding capacity of each block are determined. Using fountain coding, the reference information is embedded into the entire image. The proposed method is superior to the traditional methods in two aspects. First, the method assigns different code length to different regions so that the recovery quality for the whole image is good and significant regions can be protected effectively. Second, the method embeds different amounts of data into different regions thus avoiding false contour and ensuring good quality of the stego-image. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Object-Scene Fusion by Combining SFIM with Region Filling Journal of Applied Sciences    2014, 32 (2): 185-190.   DOI: 10.3969/j.issn.0255-8297.2014.02.011 Abstract （1630）      PDF（pc） （20218KB）（588）       Knowledge map    Save Considering the drawbacks of the Poisson fusion technique and an existing object-scene fusion method based on IHS transform, this paper proposes an improved scheme by combining smoothing filterbased intensity modulation (SFIM) with region filling making use of the advantages of IHS transform. The scheme reduces color distortion in fusion of object and scene by introducing the SFIM technique. With the hue and saturation filling, it can also fix the problems that the detail recovery cannot be increased effectively to let object get enough fusion illumination so that the object may appear inconsistent in illumination. Both subjective and objective quality assessments show that the proposed scheme can solve the above-mentioned problems. It is fast and more robust. Reference | Related Articles | Metrics | Comments（0）

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Fast Inpainting of Railway Freights Images Based on Multiple Direction Interpolation 金星1， 俞大海1,2， 韩建枫3， 李晖晖1， 韩军伟1 Journal of Applied Sciences    2014, 32 (2): 191-198.   DOI: 10.3969/j.issn.0255-8297.2014.02.012 Abstract （2127）      PDF（pc） （32360KB）（639）       Knowledge map    Save High resolution line-scan cameras produce images with missing information due to occlusion caused by foreign objects. In this paper, we propose a framework based on multiple direction interpolation for single image digital restoration to remove high tension wire (HTW) from images for railway loaded condition inspection (LCI) applications. The known region to be reconstructed is automatically segmented into smooth and edge sub-regions. The smooth regions are filled-in with bilinear interpolation based on the information in the neighborhood, which is the minimum among the gradient values in three directions. For the edge regions,the fill-in result is optimized using a data fusion method based on the information in three directions with bi-cubic interpolation. Inpainting is performed for each channel independently based on the HSI color space instead of RGB. Experimental results indicate that better restoration results can be obtained as compared with traditional Bertalmio-Sapiro-Caselles-Bellester (BSCB) and fast marching method (FMM) algorithms. The proposed algorithm can also effectively deal with inpainting of complex color images with high computational efficiency.   Reference | Related Articles | Metrics | Comments（0）

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Application of Optimized Circuit Simulation—Identification of Isomorphic Hybrid Switching SHANG Hui-liang1, LIU Yang1, LIU Zhi-dong1, DONG Wen-jie2, LI Feng1 Journal of Applied Sciences    2014, 32 (2): 199-208.   DOI: 10.3969/j.issn.0255-8297.2014.02.013 Abstract （2069）      PDF（pc） （3149KB）（789）       Knowledge map    Save This paper presents a new method for graph isomorphism identification and applies it to the identification of isomorphic hybrid switching topology. A mathematical model of hybrid switching topology is first introduced. The adjacency matrix and undirected-weighted graph description of the hybrid switching topology are presented according to the mathematical model. In this case, the problem of identifying isomorphic hybrid switching topology is transformed into isomorphism determination of the corresponding undirectedweighted graphs. An optimized version of the circuit simulation method previously presented by the authors is proposed to solve the graph isomorphism determination problem. With a small modification, the optimized circuit simulation method can solve the problem of graph isomorphism determination more efficiently. Tests of the proposed method and another method called the eigenvalue algorithm are applied in the identification of isomorphic hybrid switching topology. The results show that the optimized circuit simulation method is valid and has advantages in both identification efficiency and ability of matching corresponding vertices of the isomorphic hybrid switching topology. Reference | Related Articles | Metrics | Comments（0）

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Breakdown Model of RESURF Lateral Power Devices Based on Charge-Sharing Effect ZHANG Jun, GUO Yu-feng, HUANG Shi, YAO Jia-fei, LIN Hong, XIAO Jian Journal of Applied Sciences    2014, 32 (2): 209-214.   DOI: 10.3969/j.issn.0255-8297.2014.02.014 Abstract （2080）      PDF（pc） （2573KB）（1252）       Knowledge map    Save A breakdown model for RESURF lateral power device is developed. Based on the analysis of the breakdown mechanism in RESURF lateral power device, charges in the drift region are allocated to lateral and vertical junctions along the diagonal of the sharing area. This model can be used to investigate breakdown characteristics of the device when the drift region is fully or partially depleted. Besides, the model provides simple expressions with clear physical concepts. A new RESURF criterion is also derived to quantitate the upper and lower limits, which is useful to the design of the structure parameters. General agreements exist between the modeling results and the reported experimental results. Reference | Related Articles | Metrics | Comments（0）

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SIR Cross-Coupling Dual-Band Cavity Filter KOU Xin, XIAO Zhong-yin, HUANG Chun-yan, LI Hao, CHU Jun-jun Journal of Applied Sciences    2014, 32 (2): 215-220.   DOI: 10.3969/j.issn.0255-8297.2014.02.015 Abstract （1725）      PDF（pc） （14726KB）（631）       Knowledge map    Save Using stepped impedance resonators (SIR) as a basic resonator unit of cavity filter, a cross-coupling dual-band cavity filter is designed based on frequency transformation. According to the filter specifications,the design parameters of dual-band filter are calculated using frequency transformation. A model of SIR cross-coupling dual-band cavity filter is then established and simulated by the 3D simulation software HFSS.Simulation results show good agreement with the result of schematic circuit in ADS, indicating that the method is valid and feasible. The simulation shows that the filter size is significantly reduced, while the restrain ability of stop-band is enhanced due to cross coupling. Thus the requirements of small size and good stop-band performance of the filter are met. Reference | Related Articles | Metrics | Comments（0）

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Image Denoising Based on Anisotropic Diffusion and Sparse Representation in Shearlet Domain WU Yi-quan1,2,3, LI Li1, TAO Fei-xiang1 Journal of Applied Sciences    2014, 32 (3): 221-228.   DOI: 10.3969/j.issn.0255-8297.2014.03.001 Abstract （1676）      PDF（pc） （6890KB）（1344）       Knowledge map    Save To suppress image noise effectively and better preserve edge details, an image denoising method based on anisotropic diffusion and sparse representation in the shearlet domain is proposed. The noisy image is first decomposed into a low frequency component and several high frequency components by non-subsampled shearlet transform (NSST). The main energy of the image information is contained in the low frequency component, while the edge information and most of noise are contained in high frequency components. The K-singular value decomposition (K-SVD) algorithm is used to remove noise in low frequency component. The kernel anisotropic diffusion (KAD) algorithm is used to reduce noise in each high frequency component. The reconstructed image is obtained by inverse non-subsampled shearlet transform (INSST) for the processed low frequency and high frequency components. Noise in the image is effectively suppressed, and edge details are preserved satisfactorily. Experimental results show that, compared with the denoising methods such as wavelet combining with nonlinear diffusion method, shearlet hard threshold method, K-SVD sparse denoising method and sparse redundant denoising method in wavelet domain, the proposed method has better performance both in noise reduction and detail preservation.   Reference | Related Articles | Metrics | Comments（0）

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Design of Channel Emulator for Wideband MIMO Systems XIONG Yan-wei, ZHANG Jian-hua, ZHANG Ping Journal of Applied Sciences    2014, 32 (3): 229-236.   DOI: 10.3969/j.issn.0255-8297.2014.03.002 Abstract （1948）      PDF（pc） （5575KB）（1571）       Knowledge map    Save 4G technologies are focused on delivering high level throughput by using MIMO technology and wider signal bandwidth. To evaluate the MIMO system performance highly related to the accurate representation of the channel condition, over-the-air (OTA) test is performed with a channel emulator as an important part. In this paper, a channel emulator for wideband MIMO system is designed. Compressed sensing is used to sample analog signals as the bandwidth becomes wider. Frequency domain approaches are used to implement the emulator to reduce complexity for higher order arrays. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Cognitive MIMO System Based on Protograph LDPC Codes in Television Band WANG Kai-yao, XIAO Yang Journal of Applied Sciences    2014, 32 (3): 237-245.   Abstract （1601）      PDF（pc） （10748KB）（2551）       Knowledge map    Save In TV band, adopting the current cognitive radio schemes, the cognitive user (CU) will face the problem of TV signals. In order to solve this problem, this paper proposes a novel interference cancellation scheme based on protograph LDPC codes and virtual MIMO for cognitive radio system in television band. Protograph LDPC codes are applied to virtual MIMO cognitive radio system in the proposed scheme, and by encoding transmitting data and MIMO space-time processing, it can cancel TV signal interference and channel noise. The core idea of the proposed scheme is that, depending on the difference of channel fading between the CUs and TV station’s transmitter, the TV signal interference and channel noise are looked as a new interference at the CU receiver. By decoding received signal using protograph LDPC, the CU receiver can cancel the TV signal interference from the TV station. In an optimal situation, the proposed approach can increase about 0.620.76 times of communication capacity for the proposed cognitive radio system. Comparing with the approach of directly extracting user information, the proposed scheme obtained about 12 dB coding gain in Rayleigh flat-fading channel, and it can cancel the TV signal interference efficiently. Reference | Related Articles | Metrics | Comments（0）

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Mechanism of P2P File Distribution Based on Deterministic Network Coding HAO Kun1,2, JIN Zhi-gang1 Journal of Applied Sciences    2014, 32 (3): 246-250.   DOI: 10.3969/j.issn.0255-8297.2014.03.004 Abstract （1342）      PDF（pc） （7000KB）（840）       Knowledge map    Save  This paper proposes a P2P file distribution model based on deterministic network coding (DLNCCD).This coding method can be applied to the specific multicast uniform network topology to reduce complexity of network coding, improve decoding efficiency, and ensure maximum network coding gain. The experimental results show that the total distribution time can reduce by 10%15%, and the throughput can improve by 17%21%, and the average download time can reduce by about 20%, Therefore the performance of the file distribution system is improved. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Network Coding Based LDPC-Coded Cooperation ZHANG Shun-wai, YANG Feng-fan, TANG Lei Journal of Applied Sciences    2014, 32 (3): 251-256.   DOI: 10.3969/j.issn.0255-8297.2014.03.005 Abstract （1601）      PDF（pc） （3771KB）（1102）       Knowledge map    Save This paper proposes a cooperation scheme for network coding based on irregular binary systematic LDPC codes. The relay cooperates with two users via network coding simultaneously to improve average throughput. Outage probability of the proposed scheme is analyzed for the case that the relay just forwards parity-check bits. To efficiently decode three signals from the two users and the relay, a joint iterative decoding algorithm is used at the destination based on the joint Tanner graph. Simulation results show that the proposed network coding based LDPC-coded cooperation scheme significantly lowers outage probability compared with noncooperation schemes. In case of high SNR, the scheme can achieve obvious bit-error-ratio (BER) performance gain. Reference | Related Articles | Metrics | Comments（0）

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Shallow Sea Channel Estimation With H1 Adaptive Filtering DONG Zheng, GONG Ke-xian, GE Lin-dong Journal of Applied Sciences    2014, 32 (3): 257-262.   DOI: 10.3969/j.issn.0255-8297.2014.03.006 Abstract （1316）      PDF（pc） （9101KB）（700）       Knowledge map    Save  Shallow sea is a difficult channel for acoustic communications. Noise in shallow sea acoustic communications may be described by the S S distribution, and the channel modeled as a sparse double selective fading channel. The H1 adaptive filtering is specially designed for none-Gaussian noise, and therefore can be used for channel estimation in an S S noise environment. This paper proposes an algorithm to solve the channel estimation problem based on the H1 adaptive filtering. In addition, to solve the performance degradation problem due to serious individual pulse noise, a signal preprocessing method is proposed. The results show that the performance is improved because of the preprocessing. It is shown that the performance of the H1 adaptive filtering is better than sIPNLMS both in a sparse multipath channel and in a sparse double selective channel. Reference | Related Articles | Metrics | Comments（0）

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