2012 Vol.30

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Simplified Equalization for Cooperative Communication Systems Based on Distributed Space-Time Codes XIAO Jun, JIANG Yan-xiang, YOU Xiao-hu Journal of Applied Sciences    2012, 30 (1): 1-6.   DOI: 10.3969/j.issn.0255-8297.2012.01.001 Abstract （1755）      PDF（pc） （656KB）（1930）       Knowledge map    Save Different from traditional multi-antenna systems, cooperative communication systems are inherently time-asynchronous due to the nature of relay distribution. In this paper, we investigate cooperative communication systems based on distributed linear convolutional space-time codes. An equivalent asynchronous system model is obtained by converting the relays’ transmission delays to a zero vector of the corresponding generator polynomials. With the banded Toeplitz property of the equivalent channel matrix, we propose a block minimum mean square error equalization method using the Trench algorithm to solve the Toeplitz linear systems. In the proposed equalization method, computation of the high order banded Toeplitz linear system is simplified to that of a low order system. The method avoids high order matrix inversion operations of the traditional minimum mean square error equalization method, leading to substantial reduction of computational complexity. Simulation results show that satisfactory system performance can be achieved with non-minimumorder non-trace-orthogonal generator polynomials, proper data frame length and large delay. Related Articles | Metrics | Comments（0）

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Resource Allocation Scheme for Heterogeneous Services in Amplify-and-Forward OFDM Relay System WAN Qing-tao1;2, MA Guan-yi1 Journal of Applied Sciences    2012, 30 (1): 7-13.   DOI: 10.3969/j.issn.0255-8297.2012.01.002 Abstract （1798）      PDF（pc） （1110KB）（1233）       Knowledge map    Save This paper studies a resource allocation problem for heterogeneous services in amplify-and-forward OFDM relay system under separate power constraints. A resource allocation scheme is proposed to maximize the data rate of non-realtime service (NRTS) users while satisfying the requirement of realtime service (RTS) users. The problem is decomposed into two sub-problems: resource allocation for RTS and NRTS. The problem of RTS is solved with the Lagrangian method, while for NRTS, each subcarrier is allocated to the user with the best channel gain, and a two-step method is proposed for power allocation. First, the initial power allocation is done under the total power constraint. The subcarrier power is adjusted to satisfy the separate power constraints. A low complexity algorithm is proposed for subcarrier set allocation. Simulation results show that the proposed scheme optimizes the system performance with low complexity while satisfying the requirements of heterogeneous services users. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Fast Acquisition of Primary Synchronization Signal in LTE Systems YANG Xiu-mei1;2, XIONG Yong1;2, JIA Guo-qing1;2 Journal of Applied Sciences    2012, 30 (1): 14-18.   DOI: 10.3969/j.issn.0255-8297.2012.01.003 Abstract （1780）      PDF（pc） （706KB）（2899）       Knowledge map    Save A method is proposed to fast acquire primary synchronization signal (PSS) for cell edge users in long term evolution (LTE) systems. In this method, signals are received in the configured bandwidths of LTE networks, and the sliding mirror is then correlated. The PSS index is achieved from the local PSS correlation at peak position after a clear peak value is observed. Analysis and simulation results show that it is applicable especially to cell edge users in synchronized multi-cell networks to fast acquire PSS with low complexity. Keywords: Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Iterative Detection Decoding Based on Ordered Successive Interference Cancelation for TD-LTE Systems ZHANG Zheng-yu, QIU Ling Journal of Applied Sciences    2012, 30 (1): 19-24.   DOI: 10.3969/j.issn.0255-8297.2012.01.004 Abstract （1529）      PDF（pc） （1132KB）（1703）       Knowledge map    Save Abstract: This paper proposes an iterative detection decoding algorithm based on ordered successive interference cancelation (OSIC) for time division long term evolution (TD-LTE) multi-input multi-output (MIMO) systems. In the algorithm a multiple-codewords transmission mode is used, and the effects of adaptive modulation and coding (AMC) and hybrid automatic repeat request (HARQ) on the detection order are taken into consideration. Computation complexity of the algorithm is analyzed. Numerical results show that the proposed method can significantly improve throughput. The performance gain increases with the increase of gaps between modulation and coding levels of multiple codewords, and the increase of the number of transceiver antennas. Keywords: Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Energy Optimization and Load Balancing QoS On-Demand Routing Protocol KUO Yong-hong, GENG Chun-na, CHEN Jian Journal of Applied Sciences    2012, 30 (1): 25-30.   DOI: 10.3969/j.issn.0255-8297.2012.01.005 Abstract （1540）      PDF（pc） （836KB）（1579）       Knowledge map    Save Abstract: A multi-constrained on-demand protocol, energy optimization and load balancing QoS on-demand routing protocol (ELQRP), is proposed based on AODV for ad hoc networks. The protocol combines energy consumption and link load as the QoS parameters to establish a route. Distance information is used to control broadcasting direction of RREQ packets. Both energy and queue threshold are applied to limit the forwarding of RREQ packets, reducing unnecessary routing overhead. In the routing maintenance phase, the proposed protocol uses node energy information to restrict local repairing, preventing power exhausting nodes from building the routing. All these measures are helpful to optimize the mechanisms of routing selection, forwarding, and routing maintenance. Results of simulation with NS2 show that ELQRP can effectively improve the network performance, especially delivery rate, normalized routing overhead and end-to-end delay. Related Articles | Metrics | Comments（0） Cited: Baidu(7)

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Rate Adaptive Mechanism with Congestion Awareness of DCF Protocol in Ad Hoc Networks LEI Lei1;2, ZHOU Jin-hua1, ZHU Ying-feng1, LIU Wei-kang1 Journal of Applied Sciences    2012, 30 (1): 31-38.   DOI: 10.3969/j.issn.0255-8297.2012.01.006 Abstract （1358）      PDF（pc） （999KB）（1647）       Knowledge map    Save Abstract: We show why the carrier sense mechanism defined in IEEE 802.11DCF protocol does not support adaptive multi-rate transmissions in a physical layer, and study the congestion problem in high speed and heavy loaded multi-hop ad hoc networks. We then propose a rate adaptive mechanism with congestion awareness of DCF protocol to overcome the congestion problem. According to the channel condition, the receiver can choose the highest feasible transmission rate, and sends its chosen rate value and congestion information back to the sender. Based on the feedback information from the receiver, the sender can decide whether to transmit data packets or not. Simulation results show that the proposed protocol can effectively solve the congestion problem, and significantly improve the overall throughput of the network. Related Articles | Metrics | Comments（0）

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Resource Optimization for Fairness and Sum Rate Tradeoff in Multiuser OFDM-Based Two-Way Relaying TANG Lun1, LIU Jin1, LI Guo-jun2, CHEN Qian-bin1, WANG Guang-yu1 Journal of Applied Sciences    2012, 30 (1): 39-44.   DOI: 10.3969/j.issn.0255-8297.2012.01.007 Abstract （1815）      PDF（pc） （790KB）（1395）       Knowledge map    Save Abstract: In OFDM-based cooperative two-way relay networks, sum rate and fairness among user pairs cannot be achieved simultaneously when these user-pairs exchange their information respectively via an amplify-andforward two-way relay. This paper proposes a novel suboptimal resource allocation scheme to trade off the proportional fairness and the system sum rate. This scheme is divided into two steps to maximize the sum rate of the system subject to the constraints of total power and proportionality among user-pair data rate. First, sub-carrier optimization is processed with equal power among every subcarrier to achieve proportional fairness and improve the system sum rate. To further improve the sum rate while maintaining fairness, the total power is allocated to every sub-carrier with an iterative power allocation algorithm. Simulation demonstrates that the proposed scheme of resource allocation can achieve good tradeoff between proportional fairness and system sum rate. Keywords: Related Articles | Metrics | Comments（0） Cited: Baidu(13)

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Enumeration of Balanced Rotation-Symmetric Boolean Functions ZHANG Peng1, FU Shao-jing2, QU Long-jiang1, LI Chao1;2 Journal of Applied Sciences    2012, 30 (1): 45-51.   DOI: 10.3969/j.issn.0255-8297.2012.01.008 Abstract （1428）      PDF（pc） （528KB）（1519）       Knowledge map    Save  Rotation-symmetric Boolean functions (RSBF) that are invariant under circular translation of indices have been used as components of different cryptosystems. This paper investigates enumeration of the balanced RSBFs. Based on some improvements and analysis of the solutions of the correlative equation system, the lower bound on the number of pr-variable balanced RSBFs is improved, where p is a prime. For a general odd number n, a lower bound on the number of n-variable balanced RSBFs is provided. Related Articles | Metrics | Comments（0） Cited: Baidu(74)

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Multi-party Quantum Covert Communication with Entanglement Private-Keys CAO Dong1;2, SONG Yao-liang1 Journal of Applied Sciences    2012, 30 (1): 52-58.   DOI: 10.3969/j.issn.0255-8297.2012.01.009 Abstract （1484）      PDF（pc） （626KB）（1295）       Knowledge map    Save A novel scheme of quantum multi-party covert communication is proposed. Using a pseudo-random sequence, the random subset is selected from a set of Greenberger-Horne-Zeilinger (GHZ) shared private-key forencryption. Quantum information is rotated and hidden by disguising it as noise in a quantum error-correcting code. A subset of detection is constructed and based on the complement of shared private-keys. Based on the detection scheme of typical error, the private-key can be recycled. Compared to other protocols which require more private keys, the proposed scheme can significantly reduce key consumption. The ability of eavesdrop detection is optimized. The optimized scheme is robust to the Trojan horse attacking. Related Articles | Metrics | Comments（0）

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A Family of Protograph-Based LDPC for PR Channels CHEN Ping-ping1, FANG Yi2, WANG Lin2 Journal of Applied Sciences    2012, 30 (1): 59-66.   DOI: 10.3969/j.issn.0255-8297.2012.01.010 Abstract （1290）      PDF（pc） （1300KB）（1225）       Knowledge map    Save Abstract: For additive white Gaussian noise (AWGN) channel, Jet Propulsion Laboratory (JPL) proposed an AR4JA protograph low density parity check (LDPC) code with good bit error rate (BER) performance and simple hardware implementation. However, such a code is unsuitable for partial response (PR) channels. This paper introduces a new family of protograph LDPC (near-regular) codes, which are tailored for a typical EPR4 channel of PR channels. The finite-length extrinsic information transfer (EXIT) is also extended to PR systems based on protograph codes of limited code length. In a Monte Carlo simulation over EPR4 channel, the proposed code shows a considerable performance gain both in low- and high-SNR regions compared to regular LDPC codes with column-weight-three, and thus can be viewed as a good code for PR channels. Keywords: Related Articles | Metrics | Comments（0）

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Robust and Efficient Password-Authenticated Key Agreement Scheme Based on Elliptic Curve Cryptosystem LIU Tian-hua1, ZHU Hong-feng1, PAN Jeng-shyang2 Journal of Applied Sciences    2012, 30 (1): 67-74.   DOI: 10.3969/j.issn.0255-8297.2012.01.011 Abstract （1332）      PDF（pc） （1052KB）（1831）       Knowledge map    Save Abstract: The paper presents a new password authentication and key-exchange protocol suitable for remote users without verification table and exchanging keys over an untrusted network. The new protocol can resist dictionary attacks by either passive or active network intruders. Against an insider attacker, even weak password phrases can also be used safely. It also offers perfect forward secrecy, which protects past sessions and passwords against future compromises. Since the user passwords are stored in a form that is not plaintextequivalent to the password itself, an attacker with a smart card cannot use it directly to compromise security and immediately access the host. The proposed protocol is secure, simple, and fast, making it ideal for a wide range of applications in which secure password authentication is required. Compared with the related works, the proposed scheme is more efficient and practical for distributed or portable devices. Related Articles | Metrics | Comments（0） Cited: Baidu(18)

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Perpetual Image Hashing Based on Conformal Mapping and Zernike Moments ZHAO Yan1;2, WANG Shuo-zhong1, YAO Heng1, WU Wei1 Journal of Applied Sciences    2012, 30 (1): 75-81.   DOI: 10.3969/j.issn.0255-8297.2012.01.012 Abstract （1556）      PDF（pc） （3307KB）（1558）       Knowledge map    Save Abstract: We propose a perpetual image hashing method applicable to image authentication and tamper detection. The input image is pseudo-randomly partitioned into blocks, which are resized to become squares of a standard size and mapped to a unit circle by conformal mapping. Zernike moments of the circular-shaped “images” are calculated, and then modified by multiplying an exponent to achieve phase rotation-invariance. All amplitudes and phases of the modified Zernike moments are concatenated to form an intermediate Hash sequence. The final Hash is produced by pseudo-randomly permuting the intermediate Hash. The purpose of conformal mapping is to include information contained in the corners of square image blocks into the extracted image Hash so that the tamper detection capability is significantly enhanced. Experimental results show that the proposed method is robust against most content-preserving image processing operations. Image blocking allows the tampered regions in the image to be correctly located. Compared to some other techniques, the method has low probabilities of collision and less error in tamper detection. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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SVDD Algorithm with Spectral Unmixing for Anomaly Detection in Hyperspectral Images CHENG Bao-zhi, ZHAO Chun-hui, WANG Yu-lei Journal of Applied Sciences    2012, 30 (1): 82-88.   DOI: 10.3969/j.issn.0255-8297.2012.01.013 Abstract （1547）      PDF（pc） （876KB）（1501）       Knowledge map    Save  Without considering background interferences, the classical algorithm of support vector data description (SVDD) has relatively low detection probability in hyperspectral anomaly detection. To solve the problem, this paper presented a new algorithm based SVDD, which includes hyperspectral unmixing to separate target information from complicated background clutter. After spectral unmixing, the error datum includes abundant target information while effectively suppresses the background interference. The error datum is then mapped into a high-dimensional feature space with nonlinear SVDD. By exploiting nonlinear information between the spectral bands of hyperspectral imagery, anomaly targets are detected. The results show that the proposed algorithm can improve detection performance and decrease false alarm probability. Related Articles | Metrics | Comments（0） Cited: Baidu(10)

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Prostate Ultrasound Image Boundary Extraction Using Discrete Contour Point Set YUAN Zong-liang1, WANG Yuan-yuan1, YU Jin-hua1, CHEN Ya-qing2 Journal of Applied Sciences    2012, 30 (1): 89-95.   DOI: 10.3969/j.issn.0255-8297.2012.01.014 Abstract （1326）      PDF（pc） （1909KB）（1479）       Knowledge map    Save  A boundary extraction method based on the discrete contour point set (DCPS) is proposed for transrectal ultrasound (TRUS) prostate images. Several features of the prostate boundary are used to search candidate contour points, and a point set is picked up from them as the actual boundary by eliminating nonboundary candidate points. A coarse prostate boundary is defined by the DCPS and adjusted in a small scale to get a closer prostate boundary using a curve evolution method with a fast level set. Results of experiments for a series of TRUS images show that the proposed method can effectively overcome problems of inhomogeneous intensity distributions inside and outside the prostate, and blur or missing edges, to extract an accurate and fully-formed boundary of the prostate. Keywords: Related Articles | Metrics | Comments（0）

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Steganalysis of LSB Matching Based on Local Smoothness of Histogram WANG Ran, PING Xi-jian, ZHENG Er-gong Journal of Applied Sciences    2012, 30 (1): 96-104.   DOI: 10.3969/j.issn.0255-8297.2012.01.015 Abstract （1708）      PDF（pc） （2011KB）（1574）       Knowledge map    Save  Spatial LSB matching steganography makes the histogram of the embedded images smoother.Based on this, a new steganalytic method that can exploit smoothness changes is proposed. Smooth areas of a given image are chosen based on the value of pixel differences. A total of 15 features include smoothness of image histogram and local co-occurrence matrix, local smoothness and extreme value of pixel difference histograms and co-occurrence differences matrixes, etc., are extracted. The twice embedded process is used to eliminate the influence of different image contents. The Fisher linear discriminator is applied for classification. Results of experiments on the NRCS and UCID databases show that the proposed method has good performance in detecting LSB matching steganography from grayscale images. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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Hyperspectral Remote Sensing Estimation Model for Cd Concentration in Rice Using Support Vector Machines Lü Jie, LIU Xiang-nan Journal of Applied Sciences    2012, 30 (1): 105-110.   DOI: 10.3969/j.issn.0255-8297.2012.01.016 Abstract （1813）      PDF（pc） （2318KB）（1454）       Knowledge map    Save Research was carried out to explore possibility of using support vector machines (SVM) to estimate Cd concentration from hyperspectral reflectance. Canopy spectral measurements from rice plants were collected using an ASD field spectrometer in the experiment sites. Soil samples and rice samples were collected for chemical analysis of Cd concentrations. A normalization spectral pre-processing method was employed to improve performance of the estimation model. Wavelet transforms were adopted to denoise the rice hyperspectral. Estimation of Cd concentration was achieved by an SVM approach. Compared to the original (undenoised) hyperspectrl estimation model, the SVM model based on wavelet transforms yielded promising results with a coefficient of determination of 0.867 4 and a mean square error (MSE) of 0.001 2. The results indicate that it is possible to estimate Cd concentration in rice using wavelet transforms and SVM. This study can provide technical support for large area monitoring of heavy metals stressed crops using hyperspectral remote sensing. Related Articles | Metrics | Comments（0） Cited: Baidu(11)

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Complex-Network Effects of Multi-radio Wireless Ad Hoc Networks LU Yang, TIAN Yi-ming, WEI Zhen, WEI Zhen-chun Journal of Applied Sciences    2012, 30 (2): 111-116.   DOI: 10.3969/j.issn.0255-8297.2012.02.001 Abstract （1448）      PDF（pc） （726KB）（1151）       Knowledge map    Save Analysis of the mechanism of complex networks and wireless ad hoc networks shows that wireless ad hoc networks under certain conditions have complex network effects. A control strategy for multi-radio nodes is proposed based on the feasibility of small-world wireless ad hoc networks with multiple radio nodes. Taking into consideration the node design, the deployment of multi-radio nodes is controlled according to the network environment and clustering coefficient of the nodes. The results show that the proposed method optimizes the network topology, and increases the network’s robustness. It has theoretical and practical significance to further network optimization. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Modeling and Analysis of Communication Region of Primary Receiver in Cognitive Networks LIAO Yong, TAN Xiao-heng, CHENG Jin-bo, ZHANG Yu-xiang, YANG Hong.etc Journal of Applied Sciences    2012, 30 (2): 116-119.   DOI: 10.3969/j.issn.0255-8297.2012.02.002 Abstract （1631）      PDF（pc） （3697KB）（1159）       Knowledge map    Save By analyzing the existing cognitive network models, this paper proposes a cognitive network model in which the primary receiver is treated as a center. This solves the irrationality problem when modeling the interference region where the primary transmitter is treated as a center. Using the proposed model and the information theory, we obtain mutual quantitative restriction correlation of the primary user communication radius, cognitive user density and throughput of primary user under the condition of lowest throughput and communication interruption probability of primary users. Numerical simulation results show that the model is reasonable and effective when a primary receiver is interfered by cognitive users. Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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Localization of Collaboration Ripples in Wireless Sensor Network ZHANG Jin-yi1;3, DUAN Su-yang1, WU Yu-jian1, WANG Chun-hua1, DING Meng-ling2 Journal of Applied Sciences    2012, 30 (2): 120-127.   DOI: 10.3969/j.issn.0255-8297.2012.02.003 Abstract （1902）      PDF（pc） （949KB）（1210）       Knowledge map    Save This paper proposes a collaboration ripple algorithm for high accuracy, large range and low cost localization of large scale nodes in a wireless sensor network (WSN). A splicing network topology is designed based on a rational network topology research. Location error is reduced with collaboration among the nodes. The ripple algorithm is applied to locate unknown nodes in a unit cell to realize accurate localization of neighboring notes. Verification of the algorithm shows that the collaboration ripple location algorithm can reduce anchor nodes by 3.20%, and improve precision by 20.00%, indicating effectiveness of the proposed algorithm. Related Articles | Metrics | Comments（0） Cited: Baidu(12)

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Cyclostationarity Analysis of ZPOFDM Signals and Its Application to Classification of Multicarrier Modulation Signals CUI Wei-liang, JIANG Hua, LI Jian-qiang Journal of Applied Sciences    2012, 30 (2): 128-134.   DOI: 10.3969/j.issn.0255-8297.2012.02.004 Abstract （1874）      PDF（pc） （2717KB）（1340）       Knowledge map    Save  An improved OFDM signal recognition algorithm is proposed to distinguish the zero-padding OFDM (ZPOFDM) signal from multicarrier signals. Based on the second-order cyclic cumulant of ZPOFDM and other signals and combined with a cyclostationary test, the algorithm can classify signals such as ZPOFDM, cyclic-prefix OFDM (CPOFDM), and single carrier signals in fading channel. The theoretical analysis and simulations confirm the effectiveness of discriminating multicarrier signals in frequency selective channels without synchronization and parameters estimation. Related Articles | Metrics | Comments（0） Cited: Baidu(10)

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Blind Modulation Recognition for MIMO Signals ZHANG Lu-ping, WANG Jian-xin Journal of Applied Sciences    2012, 30 (2): 135-140.   DOI: 10.3969/j.issn.0255-8297.2012.02.005 Abstract （1863）      PDF（pc） （1247KB）（1726）       Knowledge map    Save To recognize modulation in MIMO signals, a modulation classification method based on blind source separation is proposed. Singular value decomposition of the received signal’s correlation matrix is used to estimate the number of transmitting antennas and whiten the received signal. The source signal is recovered with joint approximate diagonalisation of eigen-matrices (JADE). Based on analyses of four new spectral features and the fourth-order cumulant, a modulation recognition algorithm is proposed for six kinds of MIMO signals. The method does not need to estimate the carrier frequency and the symbol rate, thus is highly practical. Simulation results show that the proposed method has good performance. Related Articles | Metrics | Comments（0） Cited: Baidu(8)

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EBPSK Signal Detector Based on IM-SAPSO and SVM JIN Yi, WANG Ji-wu, WU Le-nan Journal of Applied Sciences    2012, 30 (2): 141-145.   DOI: 10.3969/j.issn.0255-8297.2012.02.006 Abstract （1793）      PDF（pc） （862KB）（1114）       Knowledge map    Save Parameter selection is important to the classification performance of support vector machine (SVM),which is essentially a search of optimum. This paper proposes a parameter selection method for SVM with the algorithm of improved simulated annealing particle swarm optimization (IM-SAPSO) to search the best parameters. The minimized K-fold cross-validation error is used as the object of IM-SAPSO. The optimized SVM is then used to classify the symbols 0 and 1 passing the impacting filter of an extended binary phase shift keying (EBPSK) communication system. Comparison is made for the detection performance of EBPSK detector between the proposed IM-SAPSO and other methods including those based on SVM, PSO-SVM and amplitude integral decision. Simulation results show that IM-SAPSO and SVM are significantly better than the other three methods. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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DOA Estimation of Wideband Signals Based on Cyclostationarity LIU Fu-gang1;2, DIAO Ming1 Journal of Applied Sciences    2012, 30 (2): 146-150.   DOI: 10.3969/j.issn.0255-8297.2012.02.007 Abstract （1624）      PDF（pc） （634KB）（1099）       Knowledge map    Save For direction of arrival (DOA) estimation of cyclostationarity wideband signals, by analyzing the signal’s cyclostationarity and conjugate cyclostationarity properties, a new method of DOA estimation from wideband signal is proposed based on the subspace decomposition method. The new method applies signals’ cyclostationarity and conjugate cyclostationarity information to form an extended cyclic correlation matrix.The spatial spectrum of wideband signal is obtained. The method has good performance of the cyclic MUSIC algorithm, and does not require optimal lag time to process the wideband signals. Computer simulations are conducted to show good performance in signal selective direction finding, with high resolution and interference suppression capability. Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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Real-Time Mosaicing for Aerial Videos Combined with Geographical Parameters HE Bei1, WANG Gui-jin1, SHEN Yong-ling2, LIAO Chao1, LIU Chun-hua2, LINXing-gan1 Journal of Applied Sciences    2012, 30 (2): 151-157.   DOI: 10.3969/j.issn.0255-8297.2012.02.008 Abstract （1388）      PDF（pc） （5976KB）（1826）       Knowledge map    Save Against high computational cost and severe accumulative error problems existing in the current video mosaicing methods, we propose a real-time mosaicing algorithm for aerial videos based on geographical parameters. First, we decompose the camera motion model for image registration in real time. We then estimate the principal orientation of each frame, and extend the uni-orientation manifold mosaicing algorithm to a multi-orientation algorithm. Finally, with geographical parameters, we rectify mosaicing strips locally to make sure that the mosaics are mapped precisely on the real geographical positions. Experimental results for synthetic and real videos demonstrate accuracy and the near real-time property of our algorithm, with the mosaicing speed up to 25 frames per second for videos of 640£480 resolution. Related Articles | Metrics | Comments（0）

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Sonar Image Mosaicing Based on Bionic Mechanical Pan-Tilt CHEN Jin-bo1;2, LI Heng-yu1, GONG Zhen-bang1, LUO Jun1, XIE Shao-rong1;2 Journal of Applied Sciences    2012, 30 (2): 158-164.   DOI: 10.3969/j.issn.0255-8297.2012.02.009 Abstract （2226）      PDF（pc） （4564KB）（1335）       Knowledge map    Save This paper proposes a mosaicing method of sonar images based on a bionic mechanical pantilt system. From the principle of vestibule-ocular reflex, an active compensation control system of bionic mechanical pan-tilt is established. The system can compensate the sonar image instability due to attitude variation of the sweeping survey boat or submarines during operation. To obtain sonar image mosaics, the sonar images are matched with information of the attitude sensors and GPS. Simulation experiments are performed in different environments. The results show that the model is robust and has the ability of dynamic compensation. The results show effectiveness of the system. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Hypergraph-Based Image Steganography HU Chen, WANG Jian-jun Journal of Applied Sciences    2012, 30 (2): 165-172.   DOI: 10.3969/j.issn.0255-8297.2012.02.010 Abstract （1892）      PDF（pc） （1054KB）（1341）       Knowledge map    Save This paper proposes a hypergraph-based steganographic method. In this method, pixels are divided into groups. Hyperedges are constructed by exchangeable relationship between pixels. A hypergraph that is the set of hyperedges is used to represent the cover image. By looking for hypergraph matching using a local optimal greedy algorithm, the secret message is embedded. To show effectiveness of the algorithm, it is compared with the stegangraphic approach based on graph theory for modifying cover images. It is also compared with other traditional spatial domain methods in steganalysis resistance. Experiments show that the proposed method requires less modification of pixels to result in better visual quality of the stego images. It can better resist steganalysis than other spatial domain methods. Related Articles | Metrics | Comments（0）

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Remote Sensing Image Segmentation Based on Heuristic Edge Growing LI Gang1, WAN You-chuan1, LI Meng2 Journal of Applied Sciences    2012, 30 (2): 173-180.   DOI: 10.3969/j.issn.0255-8297.2012.02.011 Abstract （1769）      PDF（pc） （3455KB）（1579）       Knowledge map    Save In view of difficulties of edge point detection and edge line linking in edge-based segmentation,this paper proposes a new segmentation method for remote sensing images based on heuristic edge growing.First, improvements are made to the Canny operator for edge point detection including adaptive wavelet de-noising, optimal double-threshold calculation and edge point decision based on total variation. A new heterogeneity index of edge linking is defined, which includes spatial heterogeneity and spectral heterogeneity.Heuristic decision of global mutual best fitting is then proposed to link broken edges of the same target as far as possible. Experiments are carried out using Quickbird image and aerial image to evaluate the proposed method. Segmentation results are compared to those obtained with eCognition, showing that the proposed method can link most edges correctly and produce accurate segmentation results. Related Articles | Metrics | Comments（0）

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Track Association Method Using Modified Fuzzy Membership JING Pei-liang, LIU Fang Journal of Applied Sciences    2012, 30 (2): 181-186.   DOI: 10.3969/j.issn.0255-8297.2012.02.012 Abstract （1369）      PDF（pc） （760KB）（1135）       Knowledge map    Save Track association is a prerequisite to track fusion in distributed multi-sensor/multi-target tracking.With the traditional method, the correct association rate seriously declines in a dense target environment.To solve this problem, this paper presents a new track association method. Traditional fuzzy membership is smoothed, and similarity among tracks is considered from a whole view. Thus a modified fuzzy membership is proposed. In addition, a training method is designed to obtain the parameters based on a priori sequential association couples. Simulation shows that the method can easily set parameters and has better performance as compared to the classical fuzzy double-threshold method, therefore more suitable to practical applications. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Cholesky Factorization for Covariance Matrix Recovery DU Hang-yuan, HAO Yan-ling, ZHAO Yu-xin, CHEN Li-juan Journal of Applied Sciences    2012, 30 (2): 187-193.   DOI: 10.3969/j.issn.0255-8297.2012.02.013 Abstract （2228）      PDF（pc） （813KB）（2371）       Knowledge map    Save  For simultaneous localization and mapping based on sparse extended information filter, we compare the principles of nearest neighbor data association, maximum likelihood data association and joint compatibility test data association, and discuss the requirements of marginal covariance matrix recovering in data association. A computationally efficient approach based on Cholesky factorization is proposed to exactly recover the marginal covariance from information matrix. In the simulation, we compare the proposed algorithm with covariance bound approximation, and analyze three common data association approaches using the proposed algorithm in SLAM based on a sparse extended information filter. The results show that the proposed recovery algorithm is suitable for various data association approaches, leading to high localization accuracy and reduced computational complexity. Performance of different data association approaches in SEIF-SLAM are discussed. Related Articles | Metrics | Comments（0）

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UAV Attitude Measurement Using Adaptive Compensation Technique GAO Ming1, XU Qing-he1, ZHAO Wen-cai2 Journal of Applied Sciences    2012, 30 (2): 194-202.   DOI: 10.3969/j.issn.0255-8297.2012.02.014 Abstract （1298）      PDF（pc） （1201KB）（1331）       Knowledge map    Save A method of ascertaining UAV attitude by compensation and positioning of the laser spot center is proposed. The method uses the principle of cooperative target attitude measurement combined with wander and spreading effects of the laser beam under actual atmospheric turbulence. A polygon is formed by calculating the center of the single frame laser spot and extracting feature point of outline constituted by center of the laser spot within unit interval. The gravity center of the polygon is taken as a reference. An adaptive attitude measurement compensation model is thus established. Numerical results show that, when the target distance is 3 km, the maximum error of the attitude angle is 0.221± by using the simulated annealing algorithm in the iterative solver and adaptive compensation. This indicates that the attitude measurement algorithm with adaptive compensation has high accuracy and good convergence. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Dynamic Positioning of Dredgers Using Nonlinear Dynamic Surface Control and Feed-Forward Compensation ZHANG Yu-hua 1;2, JIANG Jian-guo1, GAO Deng-ke1 Journal of Applied Sciences    2012, 30 (2): 203-208.   DOI: 10.3969/j.issn.0255-8297.2012.02.015 Abstract （1716）      PDF（pc） （934KB）（1242）       Knowledge map    Save To deal with difficulties in the control of dynamic positioning of dredgers under large dredging forces reaction, a method of combining dynamic surface control and feed-forward compensation is proposed to be used in dynamic positioning of dredgers. Dredging forces can be feed-forward compensated by sensors, and the dynamic surface controller guarantees global asymptotic stability of the closed-loop system. A first-order low-pass filter in the back-stepping design process allows the dynamic surface control technique to be implemented without differentiating any model nonlinearities, which can significantly simplify the design. Simulation results show that the proposed method has satisfactory performance. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Machine Vision-Aided Relative Navigation for UAV Aerial Refueling WANG Long1, DONG Xin-min1, JIA Hai-yan2 Journal of Applied Sciences    2012, 30 (2): 209-214.   DOI: 10.3969/j.issn.0255-8297.2012.02.016 Abstract （1698）      PDF（pc） （1155KB）（1511）       Knowledge map    Save To precisely obtain the relative pose of UAV during aerial refueling docking, a machine vision-aided INS/GPS/MV integrated navigation scheme is proposed. Feature extraction and match algorithm of machine vision image are studied. By introducing relative inertial errors, an extended state model of global filter is designed. GPS and machine vision measurement models are established using level-arm vectors. A global multirate extended Kalman filter based on federal framework is designed to realize multirate mutisensor data fusion. Comparison is made between the proposed algorithm and the standard EKF algorithm. Simulation shows that the proposed algorithm can effectively fuse INS/GPS/MV data. The navigation parameter precision and output bandwidth satisfy the requirements of UAV aerial refueling. It can improve UAV qualities and loosen requirements of flight control systems. Related Articles | Metrics | Comments（0） Cited: Baidu(7)

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UAV Route Planning Based on Ant Colony Optimization and Artificial Potential LI Meng, WANG Dao-bo, BAI Ting-ting, SHENG Shou-zhao Journal of Applied Sciences    2012, 30 (2): 215-220.   DOI: 10.3969/j.issn.0255-8297.2012.02.017 Abstract （1476）      PDF（pc） （672KB）（1484）       Knowledge map    Save To deal with dynamic routes planning of unmanned aerial vehicles in a complicated environment, a new method that combines ant colony optimization with artificial potential is proposed. The mission region is described as a grid model. In the route search process, ants are influenced not only by pheromone and heuristic information, but also by the potential field force. According to the node location’s potential field, the state transition rules consist of deterministic choice and probabilistic choice. The environmental perception factor is designed for dynamically adjusting the proportion of deterministic choice. In order to make full use of the known environmental information and guide the ant’s search, the potential field direction and the distance between the candidate node and the goal are used to construct comprehensive heuristic information. Simulation results show that the proposed method can effectively obtain optimal feasible routes. The optimization result is better than that of the simplex ant colony and artificial field, and has better convergence speed and optimization precision. Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Journal of Applied Sciences    2012, 30 (2): 220-220.   Abstract （1144）      PDF（pc） （83KB）（770）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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2012Vol30 No2 Journal of Applied Sciences    2012, 30 (2): 221-221.   Abstract （1044）      PDF（pc） （62KB）（1236）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2012, 30 (3): 220-.   Abstract （863）      PDF（pc） （1987KB）（827）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Energy-Efficient Distributed Relay Selection Based on Statistical Channel State Information JIANG Hai-fang, ZHANG Si-hai, ZHOU Wu-yang Journal of Applied Sciences    2012, 30 (3): 221-226.   DOI: 10.3969/j.issn.0255-8297.2012.03.001 Abstract （1569）      PDF（pc） （742KB）（1265）       Knowledge map    Save In this paper, we propose a distributed relay selection algorithm based on statistical channel state information (CSI) in amplify-and-forward (AF) cooperative networks. A tradeoff is made between energy efficiency and system outage performance. A forwarding threshold is obtained by minimizing the average total power consumption. Each relay individually decides whether to participate in forwarding the source signals according to a forwarding threshold. A distributed multiple relay selection (DMRS) algorithm is proposed, in which all candidate relays have the possibility of forwarding the signals and the threshold is obtained by numerical search. The DMRS algorithm obtains good outage performance with low power consumption. A distributed single relay selection (DSRS) algorithm with low complexity is then investigated under the assumption that only one relay forwards the signals. Simulation results indicate that the proposed algorithms provide significant performance gain in terms of energy efficiency over the existing AF relay selection algorithms. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Journal of Applied Sciences    2012, 30 (3): 221-330.   Abstract （635）      PDF（pc） （88KB）（796）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2012, 30 (3): 221-330.   Abstract （648）      PDF（pc） （48KB）（934）       Knowledge map    Save PLS download if you need Related Articles | Metrics | Comments（0）

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Cross-Layer Optimization for Wireless Mesh Network with Multi-packet Reception SHI Lei1, HAN Jiang-hong1, SHI Yi2, WEI Zhen-chun1 Journal of Applied Sciences    2012, 30 (3): 227-233.   DOI: 10.3969/j.issn.0255-8297.2012.03.002 Abstract （1363）      PDF（pc） （808KB）（990）       Knowledge map    Save Multi-packet reception (MPR) technique can effectively increase throughput of wireless networks.We establish a suitable cross-layer design model for a wireless mesh network. It is a mixed integer programming model, which cannot be solved within polynomial time in general. We then propose a near-optimal solution to be solved in polynomial time. In this solution, integer variables are released into the space of a real number field, and the original mixed integer programming model becomes a linear programming model. We can obtain the near-optimal solution by iteration. Compared with optimal solutions without MPR, we show that throughput is increased by about 300% when using MPR. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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