2015 Vol.33

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Coverage Area in Different Types of Remote Sensors:Simulation and Calculation WU Zhao-cong1, YANG Fan1, WANG Nan1, WU Yuan1, ZHU Zhuo-wa2 Journal of Applied Sciences    2015, 33 (1): 1-8.   DOI: 10.3969/j.issn.0255-8297.2015.01.001 Abstract （1368）      PDF（pc） （5219KB）（1319）       Knowledge map    Save The paper analyzes geometric coverage of common remote sensors for earth observation. These are classified into two modes: spherical circular coverage and spherical quadrilateral coverage. Projective geometries of the two coverage modes are induced and simulation models of coverage in nadir and side imaging modalities built. Based on the simulation models, a universal calculation process is established for geometric coverage of common remote sensors, including transformations among six ground and spatial coordinate systems. Simulations are carried out with real satellite and sensor parameters,showing effectiveness of the proposed calculation process. Reference | Related Articles | Metrics | Comments（0）

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Geometric Feature Representation and Building Extraction Based on Geometric Features ZHU Jun-jie1,2, FAN Xiang-tao1,2, DU Xiao-ping1,2 Journal of Applied Sciences    2015, 33 (1): 9-20.   DOI: 10.3969/j.issn.0255-8297.2015.01.002 Abstract （1178）      PDF（pc） （16252KB）（401）       Knowledge map    Save Problems exist in building extraction from high-resolution remote sensing images in terms of spectral features. For example, the same object has different spectra and different objects have the same spectrum, and geometric features of a building may be more typical than its spectral features. Having summarized some typical geometric features of buildings, building extraction is done based on their geometric features with features of area, fitting rectangle, length-to-width ratio, and main directions. The experiment shows that extracting buildings with geometric features is more effective than with spectral features.However, since image segmentation depends on spectral features so that calculation of geometric features is affected by spectral features, building extraction based on geometric features is not satisfactory. As the height feature of a building is the most typical geometryfeatures, introduction of height features into image segmentation and feature extraction is an effective way to improve accuracy of building extraction.   Reference | Related Articles | Metrics | Comments（0）

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Segmentation of SAR Image of Rivers Based on Shearlet Transform and Krawtchouk Moment Invariants WU Shi-hua1, WU Yi-quan1,2,3,4,5, ZHOU Jian-jiang1,MENG Tian-liang1, DAI Yi-mian1 Journal of Applied Sciences    2015, 33 (1): 21-31.   DOI: 10.3969/j.issn.0255-8297.2015.01.003 Abstract （1828）      PDF（pc） （2316KB）（705）       Knowledge map    Save Segmentation of synthetic aperture radar (SAR) images is a key procedure in river detection and recognition. To further improve accuracy of SAR image segmentation for rivers, a segmentation method is proposed based on Shearlet transform, Krawtchouk moment invariants, and fuzzy local information C-means (FLICM). The SAR image is first decomposed with Shearlet transform, and its texture features are extracted as the first part of the feature vector. Krawtchouk moment invariants of the image are then calculated to obtain corresponding shape features used as the second part of the feature vector. Finally, the image is clustered based on FLICM algorithm using the extracted feature vector. Thus segmentation of the river SAR image is obtained. A large number of experiments are performed. The results are compared with several recently proposed methods based on pulse coupled neural network (PCNN) combined with maximum variance ratio, and Gabor wavelet transform combined with fuzzy C-means (FCM) and FLICM clustering. It has been shown that the proposed method has clear advantages both in subjective visual effects and in terms of objective evaluation indicator such as segmentation error rate. The method can provide river segmentation with better accuracy.   Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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An Improved Strong Tracking Filtering Algorithm QIAN Hua-ming1, GE Lei1,2, HUANG Wei1 Journal of Applied Sciences    2015, 33 (1): 32-40.   DOI: 10.3969/j.issn.0255-8297.2015.01.004 Abstract （1371）      PDF（pc） （3119KB）（945）       Knowledge map    Save Strong tracking filtering (STF) sets small threshold to judge filtering divergence leading to fading factor with high probability, which causes excessive regulation of the filtering gain and makes the state estimation curve lack smoothness. By analyzing the operation mechanism of STF, improved STF (ISTF) is proposed. The proposed algorithm reduces probability of misjudging filter divergence by appropriately increasing the threshold. It determines the softening factor to suit different dimensions of the measurement equation, and thus avoids the disadvantages of the previous methods that determine the softening factor according to experiences. Simulation indicates that ISTF can maintain filtering accuracy and estimation smoothness, and is robust against sudden changes in the system state, showing its feasibility and effectiveness. Reference | Related Articles | Metrics | Comments（0）

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Numerical Study on the Relationship between Amplitudes of Ground Penetrating Radar Wave and Water Content in Soil LI Hui-jun1,2,3, ZHONG Ruo-fei1,2,3 Journal of Applied Sciences    2015, 33 (1): 41-49.   DOI: 10.3969/j.issn.0255-8297.2015.01.005 Abstract （1513）            Knowledge map    Save Water content in soil can be derived from the relation between changes in ground penetrating radar signals and the soil’s dielectric constant. Using the finite difference time domain (FDTD) method, a model of layered soil is established to simulate ground penetrating radar electromagnetic waves in the soil. The transmission characteristics of layered soil are analyzed using the model. The results indicate that a functional relation exists between the soil dielectric constant and the amplitude, i.e., the wave amplitude decreases with the increased electric constant. With an indoor soil model, the obtained relationship is verified: the computed water content agrees with the wet sensor data.   Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Reversible Data Hiding in Encrypted Images Transmitted on Demand HAN Xi-yu, QIAN Zhen-xing, ZHANG Xin-peng, JIANG Fei Journal of Applied Sciences    2015, 33 (1): 50-58.   DOI: 10.3969/j.issn.0255-8297.2015.01.006 Abstract （1813）      PDF（pc） （5246KB）（1354）       Knowledge map    Save This paper proposes a new method of reversible data hiding in encrypted images. The sender down-samples the original image and calculates the residuals to generate two sets of objects: sub-images and residuals. These are encrypted with an encryption keyand sent to the server. The server applies arithmetic coding on the encrypted residuals to generate spatial redundancy, and then hides extra data using the embedding key. With the key, the receiver obtains different versions of the data transmitted by the server. Unlike the conventional methods, a transmission-on-demand mechanism is used, which can effectively reduce the amount of transmitted data on the server. With the image perfectly recovered, the data embedding rate is greatly improved. Reference | Related Articles | Metrics | Comments（0）

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Analysis of NDVI Changes and Its Climate Factor Drivers in Ebinur Lake Basin from 1998 to 2012 WANG Er-li, ZHOU Jun-qi Journal of Applied Sciences    2015, 33 (1): 59-69.   DOI: 10.3969/j.issn.0255-8297.2015.01.007 Abstract （1469）      PDF（pc） （15823KB）（428）       Knowledge map    Save To explore the impact of climate change on vegetation cover in Ebinur Lake Basin, we apply the data set SPOT VEGETATION to study the trend of normalized difference vegetation index (NDVI) and spatial pattern in this area, using a maximum synthesis and linear regression method. Combining the annual precipitation and annual average temperature in the same period, the vegetation cover driving force of climate change is discussed through partial correlation and multiple correlation analyses. The results indicate that NDVI increases significantly, showing a good development trend. Among various natural factors, precipitation has a deeper and more widespread effect on vegetation than temperature during 15 years in Ebinur Lake Basin. In addition, about 88.9% of the studyarea is impacted by non-climate factor drivers, while 11.1% is driven by climate factors and mainly distributes in the eastern basin.   Reference | Related Articles | Metrics | Comments（0）

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Rate Control of I-Frames Based on URQ Model WANG Peng, NI Cui, ZHANG Guang-yuan, LI Ke-feng Journal of Applied Sciences    2015, 33 (1): 70-78.   DOI: 10.3969/j.issn.0255-8297.2015.01.008 Abstract （1541）      PDF（pc） （14601KB）（473）       Knowledge map    Save In high efficiency video coding, the coding efficiency of I-frames is lower than P-frames and B-frames, causing flicker artifacts, especially in low bitrates applications. We propose a rate control algorithm for I-frames based on URQ model to improve the reconstruction quality of I-frames to suppress flicker artifacts. An I-frame is classified into three regions according to their motion vectors and complexity, termed motion region, texture-rich region and smooth region. According to different sensitivities of human visual system to different regions, visually sensitive regions are allocated more target bits. The URQ model is used to calculate QPs. Experimental results demonstrate that the proposed algorithm can efficiently suppress flicker artifacts and improve subjective and objective quality of the video.   Reference | Related Articles | Metrics | Comments（0）

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Accuracy Analysis of Region Adjustment of Remote Sensing Images Based on Dual Quaternion XIAO Hui1,2, FEI Li-jia3 Journal of Applied Sciences    2015, 33 (1): 79-86.   DOI: 10.3969/j.issn.0255-8297.2015.01.009 Abstract （1281）      PDF（pc） （4465KB）（1044）       Knowledge map    Save According to the geometric algebra theory, a bundle adjustment method based on dual quaternion is presented. The method uses dual quaternion to describe rotation and translation of regional photo coordinates, and can linearize a strict collinearity equation. Constraint parameter adjustment is iteratively computed. The structure of normal equation in region adjustment based on dual quaternion is similar to that of traditional methods, with the required memory slightly increased with the increasing margins. The results show that, by arranging control points in four angle points and central point, the dual quaternion-based region adjustment can achieve relatively high measuring accuracy. Reference | Related Articles | Metrics | Comments（0）

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Forgery Detection via Inter-channel Correlation of CFA Images ZHANG Xiao-lin, FANG Zhen, ZHANG Xin-peng Journal of Applied Sciences    2015, 33 (1): 87-94.   DOI: 10.3969/j.issn.0255-8297.2015.01.010 Abstract （1324）      PDF（pc） （6270KB）（815）       Knowledge map    Save Most digital cameras use a single sensor to capture only one component among the three colors (RGB) for each pixel, together with a color filter array (CFA) interpolating the other two after data acquisition. In this work, spectral correlation introduced by inter-channel CFA interpolation is exploited to realize image authentication. By analyzing differences in the frequency spectrum between inter-channel interpolated images and the natural ones, we extract forensics features from the high frequency areas of the green-red spectral difference. After re-interpolating the test image, we detect tampered images according to changes in the forensic features. Experimental results demonstrate effectiveness in forgery detection and robustness to JPEG compression. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Color Clustering Based on Chromaticity Histogram YU Jun1, LIU Fei-hong1, WANG Zhan-feng2, YANG Jun-na1 Journal of Applied Sciences    2015, 33 (1): 95-104.   DOI: 10.3969/j.issn.0255-8297.2015.01.011 Abstract （1763）      PDF（pc） （9315KB）（1310）       Knowledge map    Save In camouflage design, extracting the dominant color from target background is an important step. A drawback of common color clustering methods is the requirement of supervision. This paper proposes an unsupervised color clustering algorithm based on the chromaticity histogram. The chromaticity histogram is established according to the CIE 1931 system. The cluster center is automatically generated based on the distribution of pixels in the coordinate system. Euclidean distances in the chroma space are calculated one by one between pixels and each cluster center. These pixels are clustered around the nearest clustering center. Experimental results show that the proposed clustering algorithm can accurately extract the dominant color, and automatically segment the color image. In addition, the algorithm uses less time in image segmentation than common algorithms. Reference | Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2015, 33 (2): 0-.   Abstract （348）      PDF（pc） （45KB）（370）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2015, 33 (2): 0-.   Abstract （479）      PDF（pc） （365KB）（423）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2015, 33 (2): 0-.   Abstract （510）      PDF（pc） （830KB）（415）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Joint Decoding Algorithm for IRA Code Combined with Network Coding in Cooperative Communications DAI Cui-qin, RAN Hai-xia Journal of Applied Sciences    2015, 33 (2): 105-116.   DOI: 10.3969/j.issn.0255-8297.2015.02.001 Abstract （1142）      PDF（pc） （2361KB）（750）       Knowledge map    Save By combining multiple information copies from different source nodes at the destination node in a cooperative relay network, we propose a joint irregular repeat accumulate (IRA) code and network coding modified decoding (JI-NMD) algorithm. We first demodulate the modulation information with soft demodulation information of each link, and extract the information copies from the relay node at the destination. This is done according to the functional relationships between the network coding at relay node and the original information in the direct link. We then update the soft demodulation information of the two copies from the direct and cooperative links in the IRA decoder, and construct a new decoding decision method. We further obtain a simplified log-likelihood ratio (LLR)method. Finally, we analyze the outage probability and spectral efficiency. Simulationresults show that the JI-NMD algorithm has lower bit error rate for QPSK and 16QAM. Reference | Related Articles | Metrics | Comments（0）

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Unsupervised Feature Analysis and Classification of Video Streams YAO Li-tao, DONG Yu-ning Journal of Applied Sciences    2015, 33 (2): 117-128.   DOI: 10.3969/j.issn.0255-8297.2015.02.002 Abstract （1130）      PDF（pc） （9812KB）（475）       Knowledge map    Save  For recognition of flow statistical features based on machine learning, the key is to select distinguishable features of different traffic flows. This paper presents several QoSrelated statistical features that can well discriminate video traffics. To make full use of the advantages of hierarchical clustering algorithm, this paper uses a flexible feature selection strategy to mark the network video streaming of different levels. Experiments are performed on a large scale real network video data. The results show that the proposed method can achieve significantly higher classification accuracy compared to existing methods. Keywords: video streaming, statistical features, QoS, traffic classification, hierarchical clustering Reference | Related Articles | Metrics | Comments（0）

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Resource Allocation for Machine-to-Machine Communications with Multiple Access in Cellular Networks LIN Qi-zhong, ZHANG Dong-mei, XU Kui, XIE Wei Journal of Applied Sciences    2015, 33 (2): 129-141.   DOI: 10.3969/j.issn.0255-8297.2015.02.003 Abstract （1164）      PDF（pc） （11534KB）（417）       Knowledge map    Save  An increasing number of machine-to-machine (M2M) devices are accessing upstream of the cellular network, while the resource is limited. This paper analyzes the resource allocation problem when M2M devices multiple access upstream with time division multiple access (TDMA) or frequency division multiple access (FDMA). An algorithm is proposed to allow sleep mode to dynamically allocate resource. By dropping a small fraction of arrivals from the devices farther out near the cell edge, the base station can increase its maximum load. While allowing dormancy and relating remaining energy with sleep mode, both the base station centrally dynamically allocating resource and devices’ distributed opportunistic uploading can achieve a network lifetime longevity compared with no sleep mode. Reference | Related Articles | Metrics | Comments（0）

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Intensity and Expansion of Partially Coherent Beam Propagating in Slant and Horizontal Atmospheric Turbulence KE Xi-zheng, WANG Wan-ting Journal of Applied Sciences    2015, 33 (2): 142-154.   DOI: 10.3969/j.issn.0255-8297.2015.02.004 Abstract （1165）      PDF（pc） （6334KB）（777）       Knowledge map    Save  Based on the generalized Huygens-Fresnel principle, we derive the cross-spectral density function using the modified von Karmon spectrum and atmospheric refractive-index structure constant issued by ITU-R. We also derive analytic expressions of intensity distribution and beam width of partially coherent Gaussian-Schell beam propagating in the atmosphere along slant and horizontal paths. The impact on the beam propagating in the two ways due to turbulence intensity, zenith, coherence length of the beam and other parameters are discussed. They are compared respectively from the perspective of normalized intensity distribution and relative expansion. The results show that the normalized intensity distribution of the beam in a free space along a horizontal path is the same as that along a slant path. The normalized intensity distribution is more concentrated, with the peak much stronger when zenith is smaller, while the effects of the turbulence become weaker. Impact on the zenith expansion, turbulence, coherence of the beam is almost consistent with the slant path. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Accurate and Low Overhead Mechanism for Measuring Available Bandwidth ZHOU Yi-qiu1, CHEN Bing1, QIAN Hong-yan1, Lü Zong-lei2 Journal of Applied Sciences    2015, 33 (2): 155-166.   DOI: 10.3969/j.issn.0255-8297.2015.02.005 Abstract （1092）      PDF（pc） （10311KB）（553）       Knowledge map    Save The available end-to-end bandwidth is an important specification in network measurement. Most tools need to spend much time in measuring and analyzing before calculating the available bandwidth. This paper proposes a low overhead mechanism for accurate and fast measurement of the available bandwidth by analyzing the cross traffic effect in the Internet. A model is established to reflect the relationship between utilization and the sending rate of probe packets, which is combined with an extended Kalman filter to obtain the new available bandwidth. This mechanism does not require any prior knowledge of the bottleneck link capacity and can reduce the effect of accuracy. Besides, the sending rate of probing packets can be much lower than the available bandwidth. Performance of the mechanism is verified numerically, showing fast response to burst cross traffic, low estimation error, and short convergence time. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Two-Dimensional DOA Estimation for Planar Array via Reduced-Dimension Capon JIANG Chi|ZHANG Xiao-fei|ZHANG Li-cen Journal of Applied Sciences    2015, 33 (2): 167-177.   DOI: 10.3969/j.issn.0255-8297.2015.02.006 Abstract （1836）      PDF（pc） （3338KB）（1053）       Knowledge map    Save This paper discusses estimation of two-dimensional (2D) direction of arrival (DOA) for a planar array, and derives a reduced-dimension Capon (RD-Capon) algorithm. The first parameter is obtained by searching the spectrum peak of transformation of the covariance matrix, obtained from the received signal. The second parameter is estimated using least squares. The algorithm uses one-dimensional global search to achieve a joint estimation of 2D DOA. This algorithm based on one-dimension local searches can avoid high computational cost within 2D-Capon algorithm by spectrum peak search, with the performance close to the 2D-Capon algorithm. The proposed algorithm can obtain automaticallypaired 2D DOA estimation for planar array. It works well for the sources with the same azimuth (or elevation). Simulation results verify the usefulness of the algorithm. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Blind Recognition of Self-Synchronized Scrambler Based on Linear Block Code ZHANG Min1,2, Lü Quan-tong1,2, ZHU Yu-xuan3 Journal of Applied Sciences    2015, 33 (2): 178-186.   DOI: 10.3969/j.issn.0255-8297.2015.02.007 Abstract （1287）      PDF（pc） （6684KB）（1183）       Knowledge map    Save A blind recognition method of self-synchronous scrambler based on the linear block code with unbiased information source is proposed. Different run characteristics of the linear block code and random sequence are analyzed, leading to the conclusion that the run feature of correctly extracted scrambler sequence differs from that of the wrong one. A polynomial of the scrambler is determined with maximum value search in all possible Euclidean distances between the run ratios of extracted and random sequences. Experiments and simulation results show correctness of the theoretical analysis. Blind recognition of self-synchronous scrambler after the linear block code with unbiased information source can be realized, useful in engineering application. Reference | Related Articles | Metrics | Comments（0）

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Adaptive Speech Enhancement for Microphone Array XU Jin1,2, ZHAO Yi-bo1,2, GUO Ye-cai1,2 Journal of Applied Sciences    2015, 33 (2): 187-193.   DOI: 10.3969/j.issn.0255-8297.2015.02.008 Abstract （1291）      PDF（pc） （2032KB）（1167）       Knowledge map    Save In a complex speech environment, microphone array speech enhancement techniques can effectively extract target speech signals and eliminate noise. In a conventional microphone array, the beam forming weighting coefficients are fixed. To flexibly control the beam forming direction of the microphone array and eliminate residual noise due to side-lobes, this paper presents an adaptive enhancement technique for microphone array speech. A microphone array with an adaptive filter is used to form a controllable generalized sidelobe canceller (GSC), followed by improved spectral subtraction with a Chebyshev window function. Simulation results show that the proposed method can effectively remove noise, improving the performance by about 3.5 dB with respect to the ordinary GSC. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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ISSR Model of Message Propagation in Microblog Networks LU Jing1,2,3, YU Xiao-qing1,2, WAN Wang-gen1,2 Journal of Applied Sciences    2015, 33 (2): 194-202.   DOI: 10.3969/j.issn.0255-8297.2015.02.009 Abstract （1634）      PDF（pc） （7705KB）（618）       Knowledge map    Save  We divide microblog users into three types: uninformed, forwarder and rejecter, and propose an uninformed-spreader-spreader-rejecter (ISSR) model based on the real situation of message propagation in a microblog network and the classical epidemic model susceptible-infectious-removed (SIR). The transmission mechanism is described in detail. We also give a steady-state analysis of the mean-field equations of the model. The network evolution model corresponding to the statistical property of real networks is built based on the crawled information from Sina microblog users in Shanghai’s typical universities. Dynamics of the networks is analyzed. Simulation results show a larger retweeting rate  and a smaller rejecting rate  may improve the spreading range of the microblog message. Meanwhile, the multiple retweeting rate  has a certain influence on the density of spreaders. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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AdaBoost Algorithm with Classification Belief YAN Chao, WU Yue, YUE Xiao-dong Journal of Applied Sciences    2015, 33 (2): 203-214.   DOI: 10.3969/j.issn.0255-8297.2015.02.010 Abstract （1418）      PDF（pc） （6680KB）（1028）       Knowledge map    Save Ensemble learning is widely accepted and used in machine learning. This paper proposes a multi-class ensemble learning algorithm named AdaBoost belief. The algorithm improves AdaBoost·SAMME by attaching weights to classes in every weak classifier. These weights, called class beliefs, are computed based on class accuracy collected in each round of the iteration. We compare the algorithm with AdaBoost·SAMME in many aspects including learning accuracy, generalization ability, and theory support. Experimental results indicate that the proposed method has a competitive learning ability and high prediction accuracy in Gaussian sets, several UCI sets, anda number of log-based intrusion detection applications. When the class number increases so that prediction of classes becomes more difficult, the prediction error rate of the proposed algorithm increases slower than AdaBoost·SAMME. Reference | Related Articles | Metrics | Comments（0）

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Design of Alliance Identity Authentication Scheme in Cloud Computing Environment WANG Chong-xia1, DING Yan2, LIU Qian2, ZHOU Xian-wei2 Journal of Applied Sciences    2015, 33 (2): 215-222.   DOI: 10.3969/j.issn.0255-8297.2015.02.011 Abstract （1069）      PDF（pc） （4599KB）（1134）       Knowledge map    Save  This paper presents a “contract”-related certification protocol in a cloud computing alliance environment. With a signature algorithm of combined public and private data, “contract” trust relationship is built among alliance clouds. By taking advantage of the trust relationship, distributed management of user identity information and “contract” related certification are realized in the cloud alliance. The proposed protocol uses bulletin board, time stamp, signature, and anti-collision hash function to reduce information interaction, effectively preventing data tampering, replay, and middle attack. Theoretical analysis shows that the proposed protocol is secure and efficient. It requires less computation and communication overhead, and provides a concise and security solution for alliance identity authentication in a cloud environment. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Journal of Applied Sciences    2015, 33 (3): 223-223.   Abstract （1004）      PDF（pc） （46KB）（1229）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2015, 33 (3): 223-223.   Abstract （1298）      PDF（pc） （359KB）（1288）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Dynamic Beamforming in Cognitive Radio Networks GUO Yan, ZHU Fang-jun, LI Ning Journal of Applied Sciences    2015, 33 (3): 223-233.   DOI: 10.3969/j.issn.0255-8297.2015.03.001 Abstract （1702）      PDF（pc） （5444KB）（1731）       Knowledge map    Save Cognitive radio network has the potential of enhancing spectrum utilization.An effective beamforming algorithm can protect primary user from excessive interference while ensuring a meaningful QoS to the secondary system. Conventional beamforming algorithms focus on stationary targets, whereas the cognitive radio nodes are mobile. Dynamic beamforming is investigated in this paper. The direction of arrival (DOA) of a moving target is tracked by a particle filter algorithm. The derived DOA estimation is then used to model the channel between the base station and the users. Three different beamforming schemes are proposed aiming at maximizing signal-to-noise ratio (SNR), minimizing inference, and SNR balancing, respectively. SNR maximization is transformed to Rayleigh-Ritz quotient, resulting in a closed-form solution. Interference minimization and SNR balancing are reformulated as secondary-order cone programming (SOCP) problems. These problems can be solved efficiently using interior point methods. Several numerical simulation examples are provided to illustrate effectiveness of our approaches. Reference | Related Articles | Metrics | Comments（0）

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Packet Loss Differentiation and Congestion Control in Heterogeneous Networks JIN Yu-bao, DONG Yu-ning Journal of Applied Sciences    2015, 33 (3): 234-242.   DOI: 10.3969/j.issn.0255-8297.2015.03.002 Abstract （1662）      PDF（pc） （7714KB）（1623）       Knowledge map    Save The existing transmission control mechanism lacks effective method in network state estimation and packet loss differentiation. To deal with the problem, this paper proposes a loss differentiation algorithm (LDA), utility based LDA (UBLDA) capable of estimating the network state (congestion or not) by calculating utility parameters based on the interval of packet arrival and sending rate. UBLDA can choose appropriate differentiation scheme based on the state estimation, and integrate with a TCP friendly transmission control protocol. It is a new multimedia transmission control mechanism suitable for wiredwireless heterogeneous networks. Simulations are performed to compare the performance of the proposed algorithm with existing methods. Reference | Related Articles | Metrics | Comments（0）

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Dynamic Network Selection Based on Game Theory in Heterogeneous Wireless Networks XIE Wei1, MA Wen-feng1, HAN Peng2, XU You-yun1 Journal of Applied Sciences    2015, 33 (3): 243-252.   DOI: 10.3969/j.issn.0255-8297.2015.03.003 Abstract （1499）      PDF（pc） （2523KB）（1047）       Knowledge map    Save  A main characteristic of the next generation wireless networks is that mobile terminals can access any networks flexibly. Network selection techniques can improve spectral efficiency and network capacity. This paper presents an efficient network selection mechanism based on non-cooperative game. The mechanism can ensure mobile users to connect to appropriate wireless networks among a heterogeneous network. We show that the proposed game is a potential game and analyze existence and feasibility of Nash equilibrium (NE). An iterative algorithm based on best response dynamics for solving the proposed game is presented. Simulation shows that the algorithm can converge to NE of the proposed game with a designed utility function, and achieve near optimal performance. Reference | Related Articles | Metrics | Comments（0）

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Parallel Optimization of Chinese Language Model Based on Recurrent Neural Network WANG Long1,2, YANG Jun-an1,2, CHEN Lei1,2, LIN Wei3, LIU Hui1,2 Journal of Applied Sciences    2015, 33 (3): 253-261.   DOI: 10.3969/j.issn.0255-8297.2015.03.004 Abstract （1910）      PDF（pc） （2539KB）（2520）       Knowledge map    Save  High computational complexity leads to low efficiency in training a recurrent neural network (RNN) language model. This becomes a major bottleneck in practical applications. To deal with this problem, this paper proposes a parallel optimization algorithm to speed up matrix and vector operations by taking the advantage of GPU’s computational capability. The optimized network can handle multiple data streams in parallel and train several sentence samples simultaneously so that the training process is significantly accelerated. Experimental results show that the model training of RNN is speeded up effectively without noticeable sacrifice of model performance. The algorithm is verified in an actual Chinese speech recognition system. Reference | Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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A MAC Layer Broadcast Mechanism in Ad Hoc Networks with Directional Antenna for Transmission and Reception LI Mo1, HUANG Sheng-bo1, ZHAO Liang2 Journal of Applied Sciences    2015, 33 (3): 262-273.   DOI: 10.3969/j.issn.0255-8297.2015.03.005 Abstract （1631）      PDF（pc） （3359KB）（1155）       Knowledge map    Save Using directional antennas for both transmission and reception provides many benefits for Ad Hoc networks such as longer transmission range and lower probability of being detected. However, applying traditional broadcast mechanisms for network layers to Ad Hoc networks will cause long delay problem. To deal with this problem, a broadcast mechanism is proposed, which uses the reservation sub-frame in the D-TDMA MAC protocol to reduce the time for delivering broadcast packets. Nodes make reservation for forwarding broadcast packets after exchanging modified handshaking messages with their neighbors. This can avoid long delay caused by waiting for receiving broadcast packets from their parent nodes. Simulation shows that, compared to the performance of planting traditional network layer broadcast mechanism into an Ad Hoc network, broadcast packets can be transmitted to all nodes more quickly by occupying smaller slots by using the proposed mechanism. Reference | Related Articles | Metrics | Comments（0）

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Source Localization Using Taylor Series Iteration with Perturbation Calibration of Emitter States Journal of Applied Sciences    2015, 33 (3): 274-289.   DOI: 10.3969/j.issn.0255-8297.2015.03.006 Abstract （1687）      PDF（pc） （2911KB）（1225）       Knowledge map    Save While most passive localization algorithms are only applicable to certain applications, the Taylor series iteration (TSI) algorithm is suitable for arbitrary settings. For this reason, a theoretical framework for deriving localization performance of TSI is discussed. Two cases, with and without calibration state error, are considered. In the former case, the corresponding Cramér-Rao lower bound (CRLB) is derived. In the latter case, the corresponding CRLB is derived and compared with the former case. Mean square error (MSE) is derived theoretically. Comparison between the theoretical MSE with the CRLB indicates that accuracy of the source location cannot reach the optimal accuracy without considering the calibration state error. To overcome the shortcoming, a two-step optimal fusion localization method based on TSI is proposed, with accuracy reaching that of CRLB. Passive localization is simulated to verify performance of the proposed algorithm, showing validity of the theoretical analysis in this paper.   Reference | Related Articles | Metrics | Comments（0）

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Adaptive JPEG Steganography Based on New Distortion Cost Function XU Miao1, CHENG Hang1,2, YU Jiang1, ZHANG Xin-peng1 Journal of Applied Sciences    2015, 33 (3): 290-298.   DOI: 10.3969/j.issn.0255-8297.2015.03.007 Abstract （1520）      PDF（pc） （10035KB）（1393）       Knowledge map    Save To improve security of steganography, this paper proposes an adaptive steganographic scheme for JPEG images based on a new distortion cost function. As texture areas in a cover image are more suitable for information embedding, the sum of absolute values of all non-zero quantized DCT coefficients in a DCT block is used to measure texture of the block. Combining the previous uniform embedding scheme, a new distortion cost function is defined. With syndrome trellis codes, embedding modification spreads uniformly over DCT coefficients of all possible magnitudes, embedding secret data adaptively into the texture areas in the cover. Experimental results show that the proposed scheme out performs the prior arts in terms of security with the same low payload. Reference | Related Articles | Metrics | Comments（0）

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Fuzzy Evaluation of Application Satisfaction for Remote Sensing Satellite WU Zhao-cong, XU Zhuo-zhi, YANG Fan Journal of Applied Sciences    2015, 33 (3): 299-308.   DOI: 10.3969/j.issn.0255-8297.2015.03.008 Abstract （1878）      PDF（pc） （1189KB）（1514）       Knowledge map    Save Reasonable evaluation of application satisfaction of remote sensing satellites is crucial for the planning and design of earth observation systems. To deal with this problem, a fuzzy comprehensive evaluation (FCE) method for remote sensing application satisfaction is proposed. Based on the remote sensing application of the projects high resolution earth observation system and space infrastructure planning, a remote sensing application model is built with four data indicators of space resolution, time resolution, spectral range and spectral resolution. With the FCE method, a factor set and an evaluation set are designed, and a series of fuzzy membership function established. By calculating the weight with the analytical hierarchical process (AHP) method, the final evaluation result is obtained from a weighted average operator. Comparison between the World Meteorological Organization (WMO) evaluation cases and the FCE evaluation results shows that using this method to evaluate remote sensing satellite application satisfaction is feasible. Reference | Related Articles | Metrics | Comments（0）

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Super Resolution Reconstruction of ZY-3 Satellite Images JIA Yong-hong1,2, Lü Zhen1, ZHOU Ming-ting1 Journal of Applied Sciences    2015, 33 (3): 309-316.   DOI: 10.3969/j.issn.0255-8297.2015.03.009 Abstract （1579）      PDF（pc） （2597KB）（1375）       Knowledge map    Save  Two refactoring approaches, one based on iterative back projection (IBP) and the other based on sparse representation and dictionary learning, are discussed. Three linear array images of the ZY-3 satellite are used to reconstruct super-resolution images. The reconstruction results are evaluated according to four objective criteria, i.e., mean brightness, PSNR, information entropy, and sharpness of images. The results obtained with the two approaches show that the sparse representation and dictionary learning method is better than the iterative back projection method. Reference | Related Articles | Metrics | Comments（0）

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Finite Time Stabilization for a Nonlinear Helicopter System JIANG Yuan, SHI Zhi-qian, DAI Ji-yang Journal of Applied Sciences    2015, 33 (3): 317-328.   DOI: 10.3969/j.issn.0255-8297.2015.03.010 Abstract （1314）      PDF（pc） （9151KB）（960）       Knowledge map    Save A finite-time control method is proposed for the CE150 helicopter with multiple inputs, strong coupling and nonlinearity. By considering the helicopter system as a cascaded one and performing coordinate transformation, a finite time nested saturation method is used to stabilize the two subsystems in finite time. The closed-loop system achieves global uniform finite-time stabilization by verifying the forward uniformity. Simulation shows effectiveness of the system, faster convergence, and better robustness. Reference | Related Articles | Metrics | Comments（0）

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Robust Estimation of Guaranteed Cost State for Complex Network with Missing Measurements WAN You-hong, AN Wei-liang, FAN Chun-xia Journal of Applied Sciences    2015, 33 (3): 329-340.   DOI: 10.3969/j.issn.0255-8297.2015.03.011 Abstract （1553）      PDF（pc） （4326KB）（1146）       Knowledge map    Save To deal with data dropouts and noise in data transmission, this paper studies robust guaranteed cost state estimation of discrete-time complex networks, and focuses on reducing influence of data dropouts and noises on state estimation. Using the Lyapunov stability theory combined with stochastic analysis, an existence condition of the gain matrix and the relevant design criteria used in the robust guaranteed cost state estimation are proposed with linear matrix inequalities. With convergence of the estimation mean-square error, the robust guaranteed cost performance requirements are satisfied. Numerical simulation shows effectiveness and applicability of the proposed design approach. Reference | Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2015, 33 (4): 0-.   Abstract （646）      PDF（pc） （368KB）（497）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Journal of Applied Sciences    2015, 33 (4): 1-.   Abstract （570）      PDF（pc） （29KB）（467）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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