2011 Vol.29

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    Cooperative Spectrum Sharing Game in Cognitive Radio Systems
    MA Liang1;2, ZHU Qi1;2;3
    Journal of Applied Sciences    2011, 29 (1): 1-8.   DOI: 10.3969/j.issn.0255-8297.2011.01.001
    Abstract2148)      PDF(pc) (704KB)(2121)       Save

     Spectrum allocation in cognitive radio systems is investigated in this paper. Based on the Nash bargaining in cooperative game, an improved utility function is proposed to maximize the profit product of all secondary users. The cooperative game algorithm for spectrum allocation in cognitive radio is used, and the priority of secondary users introduced. We show existence and uniqueness of Nash bargaining solution (NBS) for the new utility in cooperative game. Simulation results indicate that the new algorithm can reflect the secondary users’ priority of spectrum allocation by setting the parameters and make the spectrum allocation more effective and fair.

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    Cited: Baidu(6)
    Limited Quantization Feedback Design Based on Error Correction in Base Station Coordination System
    HAN Dong-sheng1;3, YANG Wei1;2, XU Chang-long2
    Journal of Applied Sciences    2011, 29 (1): 9-14.   DOI: 10.3969/j.issn.0255-8297.2011.01.002
    Abstract1963)      PDF(pc) (4420KB)(1843)       Save

     This paper proposes a limited quantization feedback mechanism based on error revising according to the characteristics of base-station coordination system. In this mechanism, the channel quantization process is divided into many steps. The number of the steps equals the number of coordinating base stations. Each quantization step corrects the errors in the previous step. From the complexity analysis and system simulations, it is concluded that the new mechanism reduces quantization complexity with very small degradation in the performance as compared to the existing global feedback mechanisms. It improves the system performance with very little increase in complexity as compared to the existing individual feedback mechanisms. The proposed mechanism provides a good tradeoff between complexity and system performance.

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    Research and Optimization of Indoor Relay Network Deployment
    PEI Yu-shan1;2, TIAN Hui1;2, WANG Ying1;2, SONG Lei1;2
    Journal of Applied Sciences    2011, 29 (1): 15-21.   DOI: 10.3969/j.issn.0255-8297.2011.01.003
    Abstract1796)      PDF(pc) (3721KB)(1603)       Save

    To deal with complex indoor wireless environments and high throughput requirements, deployment of indoor relay networks is investigated. A mathematical model is established for large office buildings, with adaptively changed parameters are adaptive to meet the practical conditions. As an example, relay network deployment in an indoor scenario with a large local environment is considered. With the proposed model, the number of access points, the locations of deployment, and the selection of relay work modes are derived based on the system performance requirements. The simulation results show that deploying relay stations in the studied environment can effectively improve the system throughput and coverage. Taking both systemperformance and network-cost into account, one base station and four amplify-forward relay stations can form an ideal deployment.

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    Effect of Atmospheric Turbulence on Maximal Zenith Angle of Satellite-to-Ground Laser Communication Links
    LI Yong-liang1, WANG Jian-yu1;2, XU Rui1, LIN Ri-zhao1, FU Zhong-qian1
    Journal of Applied Sciences    2011, 29 (1): 22-26.   DOI: 10.3969/j.issn.0255-8297.2011.01.004
    Abstract1800)      PDF(pc) (679KB)(1593)       Save

    Abstract: A concept of "maximal zenith angle" is proposed for satellite-to-ground laser communication links. A method for building the maximal zenith angle model is presented. We consider links using on-off-keying (OOK) modulation and avalanche photodiode detector (APD). Relationship among the maximal zenith angel, the nominal value of atmosphere turbulent intensity, and the bit error rate (BER) is obtained. This is done based on gamma-gamma (GG) probability density function (PDF), Web-Gaussian approximation of APD, and the Hufnagel-Valley model of the atmosphere turbulent intensity. With the laser signal power set at 2W, the simulation results show that the maximal zenith angel is clearly decreased with the nominal value
    of atmosphere turbulent intensity, and increased with BER. A empirical model of maximal zenith angel is obtained using nonlinear curve fitting.

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    SIR Calculation for Fast Iterative ICI Cancellation in STBC Cooperative OFDM System
    PENG Zhang-you1;2, LIU Yan-yan1;2, ZHANG Xing1;2
    Journal of Applied Sciences    2011, 29 (1): 27-32.   DOI: 10.3969/j.issn.0255-8297.2011.01.005
    Abstract1960)      PDF(pc) (729KB)(1603)       Save

     Based on the space time block coding (STBC) cooperative orthogonal frequency division multiplexing (OFDM) system, a method for calculating signal-to-interference ratio (SIR) is proposed to cancel inter-carrier interference (ICI) iteratively. By using the initial value of each iteration step instead of the transmitted signal, the method can calculate SIR of the received signal. For large frequency offset, a frequency compensation scheme is used. Error analysis and simulation results show that, when SIR is above 10 dB, difference between the SIR obtained with the proposed method and the theoretical results is below 10?2.

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    Cited: Baidu(13)
    Scaling Factor Quantization for LDPC Codes
    ZHANG Xiao-jun1, TIAN Ying-hong1, YU lei1, RAN feng2, LAI Zong-sheng1
    Journal of Applied Sciences    2011, 29 (1): 33-38.   DOI: 10.3969/j.issn.0255-8297.2011.01.006
    Abstract1706)      PDF(pc) (675KB)(1672)       Save

    This paper proposes a quantization scheme for low density parity check(LDPC) codes based on scaling factor by analyzing message distribution and the effect of quantization saturation. Messages are scald for the check nodes and variable nodes, and for the initial channel value. Using the scaling, the scheme allows the integer part of message to include more information, and can lower the effect of quantization saturation. Messages of nodes are quantized with (q; 0). Due to the application of integer part instead of floating point operation, the hardware complexity is significantly reduced. Simulation of (7 493, 3 048) using normalized Min-Sum displays an implementation loss of about 0.1 dB compared with floating performance.

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    Heterogeneous Cluster-Based Topology Control Algorithms for Wireless Sensor Networks
    ZHANG Xue-fan
    Journal of Applied Sciences    2011, 29 (1): 39-43.   DOI: 10.3969/j.issn.0255-8297.2011.01.007
    Abstract1550)      PDF(pc) (649KB)(1746)       Save

     In wireless sensor networks in which the topology change is small, to reduce energy consumption in cluster head selection, a cluster-based topology control algorithms is proposed. The cluster head is made much more powerful, partitioning a cluster into two rings. The outer ring is further divided into smaller sectors. This algorithm has advantages of both high efficiency in controlling cluster head center, and flexibility of multi-hop
    nodes. A system based on HCTCA can reduce the average transmission radius of nodes and inter-cluster interferences, and improve the network throughput.

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    Adaptive Despeckling Filter with Edge-Preservation for SAR Image
    XUE Cun-jin1;2, WEN Xiao-yang1;2, DONG Qing1;2
    Journal of Applied Sciences    2011, 29 (1): 44-50.   DOI: 10.3969/j.issn.0255-8297.2011.01.008
    Abstract2348)      PDF(pc) (7838KB)(2740)       Save

    To deal with the conflict between speckle removal and edge preservation in the SAR despeckling operations, we propose an adaptive despeckling filter that can preserve edges based on noise identification and edge detection oriented to SAR images. In the filter, the template’s size and shape are adaptively changed according to the noise characteristics, and the edge position and direction in homogeneous and edge regions.
    This way, noise in the SAR image is reduced, while edges are sharpened, and texture and fine structures preserved. RADARSAT-2 SAR HH images covering the North Arctic Pole obtained on August 25, 2010 are used in the experiment. The results show validation and practicability of the method.

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    Cepstrum Coefficient Based on Human Auditory Model with Application to Recognition of Acoustic Targets
    LIU Hui1;2, YANG Jun-an1;2, ZHOU Zhi-zeng3
    Journal of Applied Sciences    2011, 29 (1): 51-55.   DOI: 10.3969/j.issn.0255-8297.2011.01.009
    Abstract1693)      PDF(pc) (790KB)(1604)       Save

     This paper proposes a cepstrum coefficient model to overcome deficiency in the classic Mel-frequency cepstral coefficients (MFCC). Based on the human auditory model, two improvements are made in computing the new cepstrum features for acoustic target recognition. First, by allowing variable time-frequency resolution and to be immune to noise, wavelet packet transform (WPT) is used instead of FFT in the computation of classic MFCC. This overcomes deficiency of single resolution and reduces sensitivity to complicated battlefield environments. Second, based on the human auditory model, compression with the exponential-law is used instead of the fixed logarithm amplitude spectrum used in the classic MFCC. Experimental results show that the new algorithm can achieve significant advancement over the former method in accuracy and robustness.

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    Identification of Scripts in Document Images Using Basic Image Features
    GUO Long, PING Xi-jian, ZHOU Lin, TONG Li
    Journal of Applied Sciences    2011, 29 (1): 56-60.   DOI: 10.3969/j.issn.0255-8297.2011.01.010
    Abstract1808)      PDF(pc) (893KB)(2113)       Save

    In this paper, a novel script identification method based on basic image features (BIF) is proposed to resolve the conflict between the speed of feature extraction and accuracy of identification. According to the concept of structural approach to texture analysis, texture basic units are divided into seven types. Support vector machine (SVM) is used to train and classify the features, which describe the structure and distribution of texture basic units, to identify scripts in different languages. Experiments have been performed upon degraded document images including ten languages including Chinese, Russian, English, Japanese, Korean, Arabic, etc. Experimental results confirm that the proposed method can identify scripts accurately and efficiently. It is robust against image degradation.

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    Cited: Baidu(7)
    Language Properties for Rationality of Workflow Net System
    YAN Chun-gang1;2, JIANG Chang-jun1;2, DING Zhi-jun1;2, SUN Ping1;2
    Journal of Applied Sciences    2011, 29 (1): 61-65.   DOI: 10.3969/j.issn.0255-8297.2011.01.011
    Abstract1895)      PDF(pc) (593KB)(1767)       Save

    Soundness of workflow system is a fundamental requirement in formalizing transaction processing flow. Most current researches convert soundness of workflow net (WF-net) system to liveness and boundedness of its extended workflow net system. The soundness property is studied in this paper from the language viewpoint of the workflow net system. Net language depiction for soundness is presented to reveal the behavior
    characteristic of this basic property. Furthermore, synchronous composition and combined composition of the workflow net system is studied. Necessary and sufficient conditions are given for soundness preservation of the two composition systems. This study provides a novel approach to the modeling and analysis for composition in complex WF-net systems.

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    Routing Table Adaptation Mechanism for Kademlia Protocol
    XU Qiang1, SUN Le-chang1, ZHANG Min2, LIU Hai-tao3
    Journal of Applied Sciences    2011, 29 (1): 66-72.   DOI: 10.3969/j.issn.0255-8297.2011.01.012
    Abstract1677)      PDF(pc) (689KB)(1933)       Save

    To improve performance of distribute Hash table (DHT) networks under churn, we study an adaptive mechanism of the routing table for Kademlia protocol. Based on a quantitative analysis, we propose an algorithm for the K value to adjust the routing table size to adapt to the churn rate. The churn rate is estimated from the available data in the routing table. Simulations show that the proposed algorithm can significantly reduce lookup latency under churn and raise the network’s crash point by nearly 10%. Even when the churn rate fluctuates severely, the network still has a satisfactory performance.

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    Early TCP Traffic Classification
    PENG Jian-fen1;2, ZHOU Ya-jian1;2, WANG Cong1;2, YANG Yi-xian1;2, PING Yuan1;2
    Journal of Applied Sciences    2011, 29 (1): 73-77.   DOI: 10.3969/j.issn.0255-8297.2011.01.013
    Abstract2031)      PDF(pc) (605KB)(2026)       Save

    In order to identify classification quickly and accurately, an early traffic classification method (ETCM) is proposed. The method uses the payload size of three early packets and the server port number obtained from the TCP flow as flow feature, and classifies the traffic based on support vector machine (SVM). The results show that ETCM meets the following conditions: extracted features used, training samples selected without bias, Internet traffic related to WEB, MAIL, BitTorrent and eMule can be identified efficiently and quickly.

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    Test of Multiple Scan Chain Grafting Using Test Vector Merging
    LIU Jie1;2, LIANG Hua-guo1, YI Mao-xiang1
    Journal of Applied Sciences    2011, 29 (1): 78-82.   DOI: 10.3969/j.issn.0255-8297.2011.01.014
    Abstract1498)      PDF(pc) (537KB)(1509)       Save

     Although multiple scan chains can effectively decrease test time and reduce the test data, it requires more input channels so that the test cost is increased. To solve the problem, a grafting mechanism with multiple scan chains is proposed, which generates base vectors using a dislocation method in order to merge as many driving ends as possible based on correlation in the test vector. Experimental results show that the proposed
    scheme uses fewer channels for the test data input and provides a higher compression ratio while maintaining high-speed testing for multiple scan chains.

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    Threat-Driven On-The-Fly Verification of Navigation Model for Web Applications
    HU Li-li1;2, MIAO Huai-kou1;2, CHEN Sheng-bo1;2, MEI Jia1, GAO Hong-hao1
    Journal of Applied Sciences    2011, 29 (1): 83-92.   DOI: 10.3969/j.issn.0255-8297.2011.01.015
    Abstract1908)      PDF(pc) (692KB)(1884)       Save

    Security of network software such as Web applications has drawn much attention in the industry.Modeling and verifying Web applications involving intricate interactions are a challenge to software developers.In this paper, we propose a threaten-driven approach to model and verify the on-the-fly navigation model of Web applications. Security properties are extracted from the model based on the threaten-driven method. Using the model checking tool NuSMV, we have verified the model. The experimental results indicate that the proposed approach can avoid state space explosion to a certain extent.

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    Feedback Stabilization for a Class of Distributed Parameter Switched Systems with Time Delay
    DONG Xue-ping, WEN Rui, LIU Hong-liang
    Journal of Applied Sciences    2011, 29 (1): 92-96.   DOI: 10.3969/j.issn.0255-8297.2011.01.016
    Abstract1712)      PDF(pc) (498KB)(1582)       Save

     Feedback stabilization for a class of distributed parameter switched systems (DPSS) with time-delay is studied. By constructing Lyapunov functions and employing the Green formula, several sufficient conditions of state feedback stabilization for a class of DPSS with constant time delay are derived. These conditions are described using a group of linear matrix inequalities (LMI). Thus design of state feedback controllers of DPSS is converted to a group of LMI. The controllers can be solved efficiently with the Matlab LMI toolbox. In addition, the proposed method has the advantage that the criteria can easily be checked and applied. A numerical example is given to illustrate validity of the design method.

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    Quadratic Stability Guaranteed Cost Control for Linear Discrete-Time Switched Systems with Multiple State Time-Delays  
    SUN Wen-an1, YANG Yin1, PEI Bing-nan1, ZHANG Qiang2
    Journal of Applied Sciences    2011, 29 (1): 97-104.   DOI: 10.3969/j.issn.0255-8297.2011.01.017
    Abstract1909)      PDF(pc) (507KB)(1233)       Save

    This paper addresses quadratic stability guaranteed cost control for a class of linear discrete-time switched systems with uncertain multiple time-delays in state and input based on LMI theory. By using multiple Lyapunov functions and constructing linear matrix inequalities, several sufficient conditions for the problem under study is derived with a state-based switching law. Controllers of the subsystems are designed and the switching law obtained simultaneously. A numerical example shows effectiveness of the method.

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    Platform Framework of Complex Hybrid System Simulation Based on Colored Petri Nets
    FANG Zhe-mei, WANG Ming-zhe, YANG Cui-rong
    Journal of Applied Sciences    2011, 29 (1): 105-110.   DOI: 10.3969/j.issn.0255-8297.2011.01.018
    Abstract1737)      PDF(pc) (588KB)(2099)       Save

    This paper proposes a cross-platform framework for hybrid simulation based on the interaction between colored Petri net (CPN) and Matlab, using Petri net as a tool for simulation process control. Utilizing and extending the concept of substitution transition, with the function of fusion place and folding, this framework can accomplish complex logical modeling and establishment of imbedded continuous process for hybrid systems. Besides, the analytical function of CPN reduces difficulty in logical verification for hybrid systems with complex logical behaviors. Finally, by modeling, simulation and analysis of a simple instance, feasibility of the platform and validity of the logic are shown. It provides a new method of modeling and simulation for large and complicated hybrid systems.

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    Cited: Baidu(5)
    Analysis and Improvement of Opportunistic Routing over Wireless Mesh Networks
    WU Hai-sheng, WANG Gui-jin, LIN Xing-gang
    Journal of Applied Sciences    2011, 29 (2): 111-117.   DOI: 10.3969/j.issn.0255-8297.2011.02.001
    Abstract2074)      PDF(pc) (1217KB)(2396)       Save

    Opportunistic routing (OR) has attracted increasing attentions, and several practical protocols over wireless mesh networks (WMNs) have been proposed. Opportunistic routing protocols usually use a fixed rate to send data packet and end-to-end acknowledgement to ensure reliability, which cause congestions and duplicated retransmissions in the networks. In this paper, we propose a built-in rate control mechanism in opportunistic routing to avoid performance degradation due to network congestion. It takes full consideration of the wireless link quality and the non-deterministic multi-path characteristics of opportunistic routing. We also introduce a round-Robin packet sending fashion to reduce unnecessary retransmissions and improve throughput. Simulations show that the modified protocol significantly outperforms the state-of-the-art opportunistic routing protocol, MORE, in both single and multiple flow scenarios.

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    Optimization of Online Measurement in Wireless Mesh Networks
    HU Zhi-yuan, HU Song-hua, BO Song, HUANG Dong
    Journal of Applied Sciences    2011, 29 (2): 118-123.   DOI: 10.3969/j.issn.0255-8297.2011.02.002
    Abstract1839)      PDF(pc) (690KB)(1774)       Save

    Accurate and real-time measurement of network characteristic is essential to optimize performance of wireless mesh networks. We present architecture for online measurement of wireless mesh networks, and address the problem of location selection of measurement nodes. In order to obtain the best location of measurement nodes, an ellipse secant algorithm is developed, which combine the signal detection capability
    with the transmission capability. The optimized location of measurement nodes is selected inside a set of ellipses with the measured node and data centers respectively as the focus. Simulation results show that the online measurement architecture can achieve best tradeoff between signal detection capability and transmission capacity, and guarantee the quality of online measurement. The ellipse secant algorithm has computational
    complexity lower than the random selection algorithm.

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    Traffic Prediction-Based Adaptive Congestion Control Routing Protocol for WSN
    YANG Jun-gang1, SHI Hao-shan1, DUAN Ai-yuan2, ZHANG Long-mei1
    Journal of Applied Sciences    2011, 29 (2): 124-128.   DOI: 10.3969/j.issn.0255-8297.2011.02.003
    Abstract1983)      PDF(pc) (594KB)(1685)       Save

    Based on Ad Hoc on-demand distance vector (AODV), a routing protocol of WSN is proposed, called adaptive congestion control routing protocol based on traffic prediction (AccRPbTP). Using a time series prediction algorithm, AccRPbTP obtains the prediction value of future networks traffic, and estimates congestion level. Thus, adaptive control to route is achieved by taking diverted route in advance. NS2 experiment results show that AccRPbTP effectively improve the networks performances, especially in network congestion and load balance.

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    Cited: Baidu(15)
    Performance of Two-Hop Multi-point Cooperative Relay Communication Systems
    PENG Yu-xu, TANG Zhou-jin
    Journal of Applied Sciences    2011, 29 (2): 129-132.   DOI: 10.3969/j.issn.0255-8297.2011.02.004
    Abstract1462)      PDF(pc) (564KB)(1604)       Save

    The paper studies performance of multi-point relaying cooperative communication system using selection decode-and-forward relays over an independent and identically distributed Rayleigh fading channel. Closed-form expressions of average symbol error rate (SER) and outage probability (OP) in Rayleigh fading channels are derived using moment generating function (MGF) and hyper-geometric function. Compared with
    the traditional cooperative communication system, performance of two-hop multi-point cooperative relayingcommunication systems is better.

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    Detection of Weak Signals Generated by Surface Plasmon Resonance Biomedical Sensors Using Photodiode-Array Device
    WANG Cheng, ZHANG Wei, ZHAO Zi-chun, LIU Guo-hua
    Journal of Applied Sciences    2011, 29 (2): 133-139.   DOI: 10.3969/j.issn.0255-8297.2011.02.005
    Abstract1781)      PDF(pc) (749KB)(2113)       Save

    This paper proposes an efficient de-noising method using a photodiode-array device to improve detection capability of surface plasmon resonance (SPR) sensors. Using reference noise signals output from the photodiode-array, we combine the coherence de-noising technique and the wavelet de-noising using soft threshold so as to raise the output SNR from 40 dB to over 52 dB. Experiments of human immunoglobulin G (IgG) molecules specific combinations show that the proposed de-noising method can remarkably enhance resolution of SPR sensors. Using this method, the SPR sensor can quantitatively detect tiny change of IgG molecule contents in solution samples with an order of 10?3 mg/mL, showing an improvement of more than one order of magnitude in detection accuracy and resolution.

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    High-Capacity Text Watermarking Resistive to Print-Scan Process
    GUO Cheng-qing1;2, XU Guo-ai1;2, NIU Xin-xin1;2, LI Yang1;2
    Journal of Applied Sciences    2011, 29 (2): 140-146.   DOI: 10.3969/j.issn.0255-8297.2011.02.006
    Abstract2019)      PDF(pc) (3906KB)(2137)       Save

     Based on an analysis of the existing text watermarking techniques, a high-capacity text watermarking scheme resistive to print-and-scan processes is proposed. The binary document image is first segmented into individual characters. A multi-bit watermark is then embedded by flipping the boundary pixels of each character based on a print-scan invariant quantity and complexity of the character. A quantitative model is established to achieve the character pixel quantization, which can minimize visual distortion. Experimental results show that the proposed scheme can increase embedding capacity. It can effectively resist print-scan attacks so as to watermark hardcopy documents.

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    Cited: Baidu(5)
    Vehicle License Plate Location Based on Machine Learning
    ZHANG Pin-zheng, WANG Jian-hong
    Journal of Applied Sciences    2011, 29 (2): 147-152.   DOI: 10.3969/j.issn.0255-8297.2011.02.007
    Abstract2352)      PDF(pc) (3134KB)(2935)       Save

    This paper proposes a vehicle license plate locating method based on the Adaboost algorithm and smallest univalue segment assimilating nucleus(SUSAN) corner validation. The Adaboost algorithm is applied for initial classification in order to select target license plate region and reduce the number of candidate areas. SUSAN corner validation is then used to calculate and sort probability of each area belonging to the vehicle
    license. The area with the highest probability is taken as the detection result. Experimental results show that the proposed method is robust to different illumination conditions, and the preset parameters produce satisfactory results in different experiments.

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    Cited: Baidu(2)
    Image Retrieval Based on Homology Continuity in Multi-dimensional Space
    LIU Pei-zhong1;3, WANG Shou-jue1;2
    Journal of Applied Sciences    2011, 29 (2): 153-158.   DOI: 10.3969/j.issn.0255-8297.2011.02.008
    Abstract1734)      PDF(pc) (1457KB)(1937)       Save

    Continuity exists when an object identifiable by computer changes from one state to another.We propose a similarity metric by combining homology continuity and biomimetic distance based on multidimensional space biomimetic informatics (MDSBI) to achieve efficient image retrieval. Experiments on the COREL image database show that the proposed method can effectively improve the image retrieval efficiency.

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    Fusion Strategy of Multi-scale Image Decomposition Combined with Image Quality Evaluation
    PAN Yu, WANG Jing, SUN Quan-sen, XIA De-shen
    Journal of Applied Sciences    2011, 29 (2): 159-168.   DOI: 10.3969/j.issn.0255-8297.2011.02.009
    Abstract1762)      PDF(pc) (9512KB)(2005)       Save

    The fusion strategy of multi-scale image decomposition is the key point to improve the image fusion. To make full use of the information in the progress of multi-scale image decomposition, an image fusion strategy combined with image quality evaluation is proposed. This strategy includes two parts: first, the salient feature in the last level instead of current level is used to construct the weight which is necessary for the fusion of current level’s approximation images; second, the parameters of the image quality measurement such as spatial frequency and contrast are introduced for the fusion of detail images. The experiment demonstrates that, compared with current common fusion rules, the proposed fusion strategy has improved the quality of the fused image in subjective aspect as well in objective aspect.

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    Blind Separation of Single Channel Permuted Image Based on Double Blur Correlation
    WANG Wei1, FANG Yong1;2
    Journal of Applied Sciences    2011, 29 (2): 169-175.   DOI: 10.3969/j.issn.0255-8297.2011.02.010
    Abstract1549)      PDF(pc) (2260KB)(1455)       Save

    This paper proposes a single-channel blind separation scheme using double blur correlation for blurring permuted images. The permuted image is blurred again and the correlation coefficients of image blocks are estimated before and after double blurring. Using the estimated correlation coefficients, a mapping space is constructed. The permutation mixing matrixes can be accurately estimated by classifying the parameters in
    the mapping space, thus the source images can be separated. Simulation results show high detection accuracy for permuted images with various blurring operations. The proposed method has good robustness against Gaussian noise and lossy JPEG compression.

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    Cited: Baidu(11)
    Statistical Characteristics and Resolution Probability of Rank Reduction Spatial Spectrum in the Presence of Unexpectant Model Errors
    WANG Ding, WU Ying
    Journal of Applied Sciences    2011, 29 (2): 176-186.   DOI: 10.3969/j.issn.0255-8297.2011.02.011
    Abstract1315)      PDF(pc) (794KB)(1319)       Save

     Rank reduction estimator (RARE) can provide direction-of-arrival (DOA) estimation without knowing the (expectant) array model errors, and avoid iterative computation and local convergence. However, RARE requires the array errors model, and its angle resolution performance is affected by unexpectant model errors in practice. We analyze the angle resolution performance of RARE. The second-order error representation and statistical properties of the perturbed RARE spatial spectrum are obtained based on the derivation of three types of angle resolution probability. The theoretical analysis is validated in the numerical experiment aimed at RARE for mutual coupling self-calibration of uniform array, and direction-dependent amplitude-phase errors self-calibration.

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    Joint 2D Angle and Frequency Estimation Based on Uniform Square Array
    XU Ling-yun1;2, ZHANG Xiao-fei1, XU Zong-ze1
    Journal of Applied Sciences    2011, 29 (2): 187-194.   DOI: 10.3969/j.issn.0255-8297.2011.02.012
    Abstract1643)      PDF(pc) (658KB)(1808)       Save

    A novel joint two-dimensional angle and frequency estimation method based on a uniform square array is presented. The output signal of the antenna array is analyzed, showing quadrilinear model characteristics. The source parameters can be estimated from the matrices via low-rank decomposition based on uniqueness of PARAFAC decomposition. The algorithm first uses the quadrilinear alternating least square (QALS) algorithm to estimate the direction and frequency matrices. It then estimates frequencies according to Vandermonde characteristics of frequency matrix and least square principle. DOAs are estimated from the characteristics of direction matrix and the least square principle. The method does not need to search spectral
    peaks or parameter pairs. Compared with ESPRIT and the trilinear model, the proposed algorithm has high precision in parameter estimation, and works well with small sizes. Simulation results verify its effectiveness.

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    Single Channel Blind Source Separation of Digital Mixtures Using Particle Filtering and Support Vector Machine
    LUAN Hai-yan1, JIANG Hua1, LIU Xiao-bao2
    Journal of Applied Sciences    2011, 29 (2): 195-202.   DOI: 10.3969/j.issn.0255-8297.2011.02.013
    Abstract2142)      PDF(pc) (623KB)(1888)       Save

     To reduce computation complexity in the particle-filtering based blind source separation, a novel eparation algorithm of co-frequency digital modulated mixture is proposed, which combines the particle filtering lgorithm with support vector machine. Formulae for assigning particle weights and expression for stimating a posterior distribution function are derived. Performance of the proposed algorithm is analyzed in wo aspects: statistic characteristics of the estimated posterior density function and its computation complexity. he estimated posterior density function is shown to be close to the true function. Both the theoretical nalysis and simulation results show that the proposed algorithm can reduce processing time without loss of
    performance in terms of bit error probability as compared with the particle-filtering based blind source separation lgorithm.

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    Cited: Baidu(20)
    The Accelerated ?-Leap Simulation Method for Biochemical Reaction Systems
    YI Na, ZHUANG Gang, WANG Yi-fei
    Journal of Applied Sciences    2011, 29 (2): 203-208.   DOI: 10.3969/j.issn.0255-8297.2011.02.014
    Abstract1726)      PDF(pc) (609KB)(1920)       Save

    This paper redefines critical reaction. It is more reasonable to demarcate reactions which may have negative reactants. Based on the definition, the accelerated ? -leap algorithm is proposed. Even if the number of some species in biochemical systems is small, the ? -leap algorithm is adaptive. This algorithm also increases the speed of simulation. The accurate stochastic simulation algorithm (SSA) algorithm, an improved ? -leap algorithm and the present accelerated algorithm are compared in two biochemical reaction models. Numerical results demonstrate that the proposed method is faster under the same simulation precision.

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    Subspace Identification in Time-Domain for Fractional Order Systems Based on Short Memory Principle
    LIAO Zeng, PENG Cheng, WANG Yong
    Journal of Applied Sciences    2011, 29 (2): 209-215.   DOI: 10.3969/j.issn.0255-8297.2011.02.015
    Abstract1583)      PDF(pc) (621KB)(1434)       Save

     A subspace identification algorithm in the time-domain based on short memory principle is given for multivariable fractional order systems. This algorithm can effectively identify the coefficient matrixes and the fractional differential order of multivariable fractional order systems. Utilizing the Poisson moment functionals (PMF), input and output signals are filtered, and the basic input and output data matrixes in subspace method constructed. The problem of identifying fractional differential order is transformed into a parameter optimization problem according to the cost function. Using the short memory principle of fractional differentiation, the fractional differential order is separated from input and output data matrixes, and differentiation calculation of input and output signals is avoided. A numerical example is given to validate the proposed algorithm.

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    Cited: Baidu(4)
    Active Vibration Control Based on Online Real-Time Identification of Control Channel
    HUANG Quan-zhen, ZHU Xiao-jin, GAO Shou-wei, GAO Zhi-yuan, SHAO Yong
    Journal of Applied Sciences    2011, 29 (2): 216-220.   DOI: 10.3969/j.issn.0255-8297.2011.02.016
    Abstract1752)      PDF(pc) (624KB)(1848)       Save

     In view of the limitation of practicality and applicability of generally used offline identification, we propose an active vibration control algorithm based on online control channel real-time identification by analyzing the basic control structure and identification strategy. We introduce random noise at the control output and achieve real-time online identification for the control channel using an FIR filter. A filtered-X algorithm is employed for the control. The controller architecture and algorithm process is illustrated. Experiments are performed on the active vibration control platform to assess the identification results. The results show that the proposed control algorithm is feasible and effective.

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    Cited: Baidu(2)
    Novel Trusted Routing in Wireless Mesh Networks
    YANG Kai, MA Jian-feng, YANG Chao
    Journal of Applied Sciences    2011, 29 (3): 221-227.   DOI: 10.3969/j.issn.0255-8297.2011.03.001
    Abstract1827)      PDF(pc) (626KB)(2190)       Save

    Because of the inherent characteristics of wireless mesh networks (WMN), the existing trust models are not applicable. This paper proposes a novel subjective logic based reputation model to detect and isolate malicious nodes in WMN. The model can also differentiate between malicious packet drop and the packet drop due to poor link quality. The model is applied to radio-metric ad hoc on-demand distance vector routing (RMAODV)
    to obtain a trusted routing T-AODV. Simulation results show that the proposed scheme can effectively evaluate trustworthiness of nodes, resist attacks to some extent and improve overall reliability, robustness and security of the network.

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    Cross-Layer Design in Multiuser MIMO-OFDM Systems Based on Space-Time Block Coding for IEEE 802.16
    XIE Wei1;2, YU Jiang2
    Journal of Applied Sciences    2011, 29 (3): 228-232.   DOI: 10.3969/j.issn.0255-8297.2011.03.002
    Abstract1745)      PDF(pc) (593KB)(1334)       Save

    Cross-layer design of packet scheduling and adaptive resource allocation in multiuser MIMO-OFDM systems are investigated based on space-time block coding (STBC). Different types of service are grouped into four types according to the 802.16 protocol. A two-layer scheduling architecture is then used to shape traffic at medium access (MAC) layer: the first layer schedule packets for different users of the same service type, and the second for different service types. A resource allocation algorithm is proposed to efficiently allocate wireless resource at physical layer according to the scheduling results of the MAC layer and the channel state information. Simulation results show that the proposed algorithm can achieve significant improvement in packet drop rate, packet delay, and system throughput as compared to an existing method.

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    Cited: Baidu(4)
    Channel Allocation Scheme for Multiuser Cooperative Networks
    HAN Ling-juan, ZHANG Si-hai, ZHOU Wu-yang
    Journal of Applied Sciences    2011, 29 (3): 233-237.   DOI: 10.3969/j.issn.0255-8297.2011.03.003
    Abstract1757)      PDF(pc) (654KB)(1883)       Save

     We study the channel allocation scheme for cooperation network with the aim of improving system throughput in addition to meeting QoS requirements. A suboptimal heuristic algorithm is proposed and implemented by using virtual nodes. The method simplifies joint channel allocation and cooperation by considering direct transmissions only. The proposed algorithm achieves adaptive allocation. Simulation results indicate
    that the proposed algorithm significantly outperforms previous works in terms of system throughput and QoS.

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    Design of Multi-element Transmitting Antenna for Indoor Visible Light Communication
    DING De-qiang, KE Xi-zheng, LI Jian-xun
    Journal of Applied Sciences    2011, 29 (3): 238-242.   DOI: 10.3969/j.issn.0255-8297.2011.03.004
    Abstract1570)      PDF(pc) (894KB)(1604)       Save

     A multi-element transmitting antenna composed of white LEDs based on a new white LED radiation model is designed. Effects of parameters used in the design on the distribution of received indoor power are studied, including element layout, LED optical axis polar angle, layer distance, and number of elements. Based on simulation, reasonable design parameters of the transmitting antenna are presented. By controlling
    transmitted power of the LED, a design method for transmitting antenna with flat-top distribution of received power is obtained. Simulation and experiments verify the new white LED radiation model.

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    Cited: Baidu(5)
    Achievable Secrecy Rate of Multiple-Level Relay-Eavesdropper Channel
    CHEN Ying, WANG Bao-yun
    Journal of Applied Sciences    2011, 29 (3): 243-250.   DOI: 10.3969/j.issn.0255-8297.2011.03.005
    Abstract1672)      PDF(pc) (600KB)(1843)       Save

    Security of a multiple-level relay-eavesdropper channel is studied, and the rate-equivocation region and achievable secrecy rate are derived in a discrete memoryless channel and a Gaussian channel, respectively. In particular, we analyze the achievable secrecy rate in two-level relay-eavesdropper and one relay-eavesdropper channels in the Gaussian channel under a limited power, and compare their achievable secrecy rate by simulation. The results show that a higher achievable secrecy rate is achieved in the multiple-level relay-eavesdropper channel when the relay node is far away from the source node. Therefore, security of the multiple-level relayeavesdropper channel is generally better.

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    Cited: Baidu(6)
    Downlink Pre-coding for Multi-user MIMO System with Successive Iterative Optimal SLNR
    GAO Xian-kun, CUI Yan, FU Hong-liang
    Journal of Applied Sciences    2011, 29 (3): 251-255.   DOI: 10.3969/j.issn.0255-8297.2011.03.016
    Abstract2262)      PDF(pc) (666KB)(1428)       Save

    In the downlink of a multi-user MIMO system, an appropriate pre-coding algorithm is needed to suppress co-channel interference. Based on the criterion of maximum signal-to-leakage-and-noise-ratio (SLNR), a successive iterative optimization pre-coding scheme is proposed. The method uses the unused subspace of known users to improve the space degree-of-freedom of the other users, and reduces the leakage. An iterative optimal method is applied to further suppress multi-user interference (MUI) and improve the signal-to-interference-and-noise-ratio (SINR) at the receiver. The proposed scheme only makes use of the channel information of the users at the transmitter to optimize the pre-coding matrix without collaboration between the base stations and the users. Any detection algorithm can be selected at the receiver without increasing the system overhead. Simulation results show that the proposed scheme has better performance and faster convergence than the original SLNR algorithm, and therefore is suitable for practical applications.

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    Cited: Baidu(5)