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2007 Vol. 29, No. 10
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Display Method:
2007, 29(10): 2287-2291.
doi: 10.3724/SP.J.1146.2006.01751
Abstract:
Color can provide an efficient visual cue for tracking based on appearance models. However, the apparent color of an object depends upon the illumination conditions, the viewing geometry and the camera parameters, all of which can vary during tracking and therefore make the tracking based on apparent color models unreliable or even failed. In this paper a mean shift tracking algorithm is proposed based on dynamic corrected fuzzy color histogram, which employs local background information around the target to correct the apparent models and overcomes the sensitive of conventional color histogram to illumination change and noise. The algorithm is tested on several image sequences and the results show that it can smooth the similarity surface and achieve robust and reliable frame-rate tracking under varying illumination conditions.
Color can provide an efficient visual cue for tracking based on appearance models. However, the apparent color of an object depends upon the illumination conditions, the viewing geometry and the camera parameters, all of which can vary during tracking and therefore make the tracking based on apparent color models unreliable or even failed. In this paper a mean shift tracking algorithm is proposed based on dynamic corrected fuzzy color histogram, which employs local background information around the target to correct the apparent models and overcomes the sensitive of conventional color histogram to illumination change and noise. The algorithm is tested on several image sequences and the results show that it can smooth the similarity surface and achieve robust and reliable frame-rate tracking under varying illumination conditions.
2007, 29(10): 2292-2295.
doi: 10.3724/SP.J.1146.2006.00017
Abstract:
To solve the problem of data association in maneuvering target tracking, a new method of data association is proposed. Being different from the Probabilistic Data Association Filter (PDAF), the proposed method assumes that the current turn rate of a maneuvering target changes within a limited range in data association. Therefore, the forecasting center is not a point but a short line. The distance between a measurement and the short line is utilized to compute the weight factor of the measurement. Simulation results show that the proposed method reduces the percentage of lost tracks and improves the state estimating accuracy in tracking a maneuvering target under the circumstance of clutter.
To solve the problem of data association in maneuvering target tracking, a new method of data association is proposed. Being different from the Probabilistic Data Association Filter (PDAF), the proposed method assumes that the current turn rate of a maneuvering target changes within a limited range in data association. Therefore, the forecasting center is not a point but a short line. The distance between a measurement and the short line is utilized to compute the weight factor of the measurement. Simulation results show that the proposed method reduces the percentage of lost tracks and improves the state estimating accuracy in tracking a maneuvering target under the circumstance of clutter.
2007, 29(10): 2296-2300.
doi: 10.3724/SP.J.1146.2006.01367
Abstract:
With a method of series expansion for image reconstruction, there exists great difficulties in terms of slow reconstruction due to bulk data to deal with. This paper presents the symmetric structure of projection lines for image reconstruction and provides a simplified algorithm for the coefficients of projection matrix via this symmetric structure, thereby an ad hoc method of fast Symmetric Block-Iterative Reconstruction Technique (SB-IRT) is introduced to solve the image reconstruction problem. The experimental image reconstruction utilizing the symmetric block-iterative algorithm with both simulated and experimental projection data is undertaken. In comparison with the performance of other conventional algorithms, the results show that the image reconstruction using the presented algorithm is much faster, and the reconstruction images has much better precision than the others.
With a method of series expansion for image reconstruction, there exists great difficulties in terms of slow reconstruction due to bulk data to deal with. This paper presents the symmetric structure of projection lines for image reconstruction and provides a simplified algorithm for the coefficients of projection matrix via this symmetric structure, thereby an ad hoc method of fast Symmetric Block-Iterative Reconstruction Technique (SB-IRT) is introduced to solve the image reconstruction problem. The experimental image reconstruction utilizing the symmetric block-iterative algorithm with both simulated and experimental projection data is undertaken. In comparison with the performance of other conventional algorithms, the results show that the image reconstruction using the presented algorithm is much faster, and the reconstruction images has much better precision than the others.
2007, 29(10): 2301-2304.
doi: 10.3724/SP.J.1146.2006.00356
Abstract:
Brushlet is a novel tool for image orientation analysis, whose energy feature is adopted in texture segmentation, image classification and denoising. In this paper, the property of Brushlet is used: the transform is a complex value function with a phase, the energy and phase information are adopted as a fused feature for texture classification. Experiments on homogeneous, inhomogeneous images and total Brodatz texture alblum prove that the complex feature of Brushlet outperforms the method based on single energy.
Brushlet is a novel tool for image orientation analysis, whose energy feature is adopted in texture segmentation, image classification and denoising. In this paper, the property of Brushlet is used: the transform is a complex value function with a phase, the energy and phase information are adopted as a fused feature for texture classification. Experiments on homogeneous, inhomogeneous images and total Brodatz texture alblum prove that the complex feature of Brushlet outperforms the method based on single energy.
2007, 29(10): 2305-2308.
doi: 10.3724/SP.J.1146.2006.00396
Abstract:
Matched filter is the optimal detector of LFM echo under the Gaussian white noise background, and the estimation of target range can be achieved according to the peak position of the matched filters output. The colored reverberation background and the mismatch between echo and replica caused by targets radial velocity will both degrade the detection performance and the distance estimation precision. Combining the ranging property of matched filter and the focusing property of fractional Fourier transform to LFM signal, this paper proposes the joint detection method based on matched filter and discrete fractional Fourier transform. Simulation results show the joint detection method performs better than the pure matched filter, and the approximate estimation of targets radial velocity can be obtained by the joint detection method.
Matched filter is the optimal detector of LFM echo under the Gaussian white noise background, and the estimation of target range can be achieved according to the peak position of the matched filters output. The colored reverberation background and the mismatch between echo and replica caused by targets radial velocity will both degrade the detection performance and the distance estimation precision. Combining the ranging property of matched filter and the focusing property of fractional Fourier transform to LFM signal, this paper proposes the joint detection method based on matched filter and discrete fractional Fourier transform. Simulation results show the joint detection method performs better than the pure matched filter, and the approximate estimation of targets radial velocity can be obtained by the joint detection method.
2007, 29(10): 2309-2312.
doi: 10.3724/SP.J.1146.2006.00956
Abstract:
The problem of concern here was the two-dimensional (2-D) harmonic frequency estimation in colored non-Gaussian noise. The 2-D cumulant projection theorem of complex linear non-Gaussian process was presented. The noise auto-correlation estimation was obtained based on this theorem by skillfully constructing a high-order cumulant of the complex noisy harmonic. Then a generalized eigen-value problem was solved to prewhiten the noise space. Finally 2-D MUSIC was employed to retrieve the 2-D harmonic frequencies. This method can effectively extract frequencies from colored non-Gaussian noise, even though the noise is symmetrically-distributed or there exists quadratic phase coupling. Theory and algorithm are illustrated by simulation examples.
The problem of concern here was the two-dimensional (2-D) harmonic frequency estimation in colored non-Gaussian noise. The 2-D cumulant projection theorem of complex linear non-Gaussian process was presented. The noise auto-correlation estimation was obtained based on this theorem by skillfully constructing a high-order cumulant of the complex noisy harmonic. Then a generalized eigen-value problem was solved to prewhiten the noise space. Finally 2-D MUSIC was employed to retrieve the 2-D harmonic frequencies. This method can effectively extract frequencies from colored non-Gaussian noise, even though the noise is symmetrically-distributed or there exists quadratic phase coupling. Theory and algorithm are illustrated by simulation examples.
2007, 29(10): 2313-2315.
doi: 10.3724/SP.J.1146.2006.00464
Abstract:
The statistics of the multiplicative and additive noise included in the sampled data is changed with squaring the sampled data. Cubic nonlinear coupling problem in zero mean independent noise is studied using a special fourth-order time-average moment spectrum. The theory analysis and the proof for the method are developed at details. Because the method may well applied to the situation where the mean of the noise is nonzero, so the method used in does not need any constrain on the mean, distribution, and the color of the noise. The simulation results illustrate the effectiveness and correctness of the proposed method.
The statistics of the multiplicative and additive noise included in the sampled data is changed with squaring the sampled data. Cubic nonlinear coupling problem in zero mean independent noise is studied using a special fourth-order time-average moment spectrum. The theory analysis and the proof for the method are developed at details. Because the method may well applied to the situation where the mean of the noise is nonzero, so the method used in does not need any constrain on the mean, distribution, and the color of the noise. The simulation results illustrate the effectiveness and correctness of the proposed method.
2007, 29(10): 2316-2320.
doi: 10.3724/SP.J.1146.2006.01819
Abstract:
Based on the model of Pulse Coupled Neural Network (PCNN) and the model of Nonlinear Anisotropic Diffusion (NAD), an improved model named ADPCNN is proposed and analyzed in theory. The new model resolves the problems of diffusion number of NAD model and the modification rule of pixel gray value of PCNN model. The application to medical image processing shows the good effect of the new model.
Based on the model of Pulse Coupled Neural Network (PCNN) and the model of Nonlinear Anisotropic Diffusion (NAD), an improved model named ADPCNN is proposed and analyzed in theory. The new model resolves the problems of diffusion number of NAD model and the modification rule of pixel gray value of PCNN model. The application to medical image processing shows the good effect of the new model.
2007, 29(10): 2321-2324.
doi: 10.3724/SP.J.1146.2006.00292
Abstract:
Considering the bad effect of steering vector errors on speech enhancement performance, a new blind beamforming based speech enhancement method is introduced in this paper. The blind beamforming combines fourth-order cross cumulant and Linear Constrained Minimum Variance (LCMV) beamformer, which makes it robust to the steering vector. A multi-channel post-processor is then used to suppress the residual nonstationary noise. Simulations results demonstrate that the proposed method exhibits good noise suppression performance even with the unknown prior knowledge about direction of arrive with respect to speech signal.
Considering the bad effect of steering vector errors on speech enhancement performance, a new blind beamforming based speech enhancement method is introduced in this paper. The blind beamforming combines fourth-order cross cumulant and Linear Constrained Minimum Variance (LCMV) beamformer, which makes it robust to the steering vector. A multi-channel post-processor is then used to suppress the residual nonstationary noise. Simulations results demonstrate that the proposed method exhibits good noise suppression performance even with the unknown prior knowledge about direction of arrive with respect to speech signal.
2007, 29(10): 2325-2328.
doi: 10.3724/SP.J.1146.2006.00247
Abstract:
Multiple Unmanned Aerial Vehicles (UAVs) cooperative searching is an important research area in cooperative control. The objective is reducing the uncertainty of the search area and achieving the information about it. This paper presents an approach which combines Model Predictive Control (MPC) theory with the Genetic Algorithm (GA) to solve this problem. First, the formal representation of the search environment is established, the multi-UAV is modeled as a controlled system and the predictive model of the system is presented. Considering the uncertainty of the sensor measurement and the environment, a Search Probability Map (SPM) is defined and the updating method based on Bayes formula is presented. Based on SPM, information gain is defined to measure the search effects and used to be the optimization object in the predictive horizon. By using of GA, the solution of the optimization problem is got and it is taken as the input of the controlled system. Simulation results demonstrate the efficiency of the algorithm.
Multiple Unmanned Aerial Vehicles (UAVs) cooperative searching is an important research area in cooperative control. The objective is reducing the uncertainty of the search area and achieving the information about it. This paper presents an approach which combines Model Predictive Control (MPC) theory with the Genetic Algorithm (GA) to solve this problem. First, the formal representation of the search environment is established, the multi-UAV is modeled as a controlled system and the predictive model of the system is presented. Considering the uncertainty of the sensor measurement and the environment, a Search Probability Map (SPM) is defined and the updating method based on Bayes formula is presented. Based on SPM, information gain is defined to measure the search effects and used to be the optimization object in the predictive horizon. By using of GA, the solution of the optimization problem is got and it is taken as the input of the controlled system. Simulation results demonstrate the efficiency of the algorithm.
2007, 29(10): 2329-2332.
doi: 10.3724/SP.J.1146.2006.00291
Abstract:
The information of radar emitter acquired by reconnaissance equipment is partial and fuzzy under complicated electromagnetic environment. For this reason, this paper firstly analyzes the characteristics of modern radar ELINT, and then identifies radar emitter by means of Dempster-Shafer fusion method based on multi-data from various kinds of reconnaissance equipment. It designs Basic Probability Assignment Function (BPAF) of emitter characters. It presents a three-degree fusion algorithm, including emitter character fusion, multiple reconnaissance period time fusion, and multiple reconnaissance equipment space fusion. The fusion algorithm is proved to have superior performance with the help of simulation results.
The information of radar emitter acquired by reconnaissance equipment is partial and fuzzy under complicated electromagnetic environment. For this reason, this paper firstly analyzes the characteristics of modern radar ELINT, and then identifies radar emitter by means of Dempster-Shafer fusion method based on multi-data from various kinds of reconnaissance equipment. It designs Basic Probability Assignment Function (BPAF) of emitter characters. It presents a three-degree fusion algorithm, including emitter character fusion, multiple reconnaissance period time fusion, and multiple reconnaissance equipment space fusion. The fusion algorithm is proved to have superior performance with the help of simulation results.
2007, 29(10): 2333-2336.
doi: 10.3724/SP.J.1146.2006.00494
Abstract:
The baseline error and gain and phase error of satellites have a great influence on the clutter cancellation and moving target relocation. As for the measurement of satellite baselines, only an order of decimeter precision can be obtained just by instruments. Fortunately, the error can be estimated and corrected by signal processing. In this paper, a new estimation method is proposed. The performance of moving target detection by space-time adaptive processing is analyzed on the basis of the precision offered by this estimation method. Finally, its validity is illustrated through computer simulations.
The baseline error and gain and phase error of satellites have a great influence on the clutter cancellation and moving target relocation. As for the measurement of satellite baselines, only an order of decimeter precision can be obtained just by instruments. Fortunately, the error can be estimated and corrected by signal processing. In this paper, a new estimation method is proposed. The performance of moving target detection by space-time adaptive processing is analyzed on the basis of the precision offered by this estimation method. Finally, its validity is illustrated through computer simulations.
2007, 29(10): 2337-2340.
doi: 10.3724/SP.J.1146.2006.00314
Abstract:
Due to the motion of a target, radar return signals are usually LFM signals with unknown frequency and unknown frequency modulated rate. Fractional Fourier transform has recently attracted much attention in detection and parameter estimation of multi-component LFM signals. Fractional Fourier transform of LFM signal of finite duration is derived and a relation between coordinate of the peak and unknown parameters is given. Statistical characteristic of LFM signal with white noise in fractional Fourier domain is studied, a closed form expression is found for Signal-to-Noise Ratio(SNR), and it is compared with matched filter of ideal situation (i.e. parameters of LFM signal are known).
Due to the motion of a target, radar return signals are usually LFM signals with unknown frequency and unknown frequency modulated rate. Fractional Fourier transform has recently attracted much attention in detection and parameter estimation of multi-component LFM signals. Fractional Fourier transform of LFM signal of finite duration is derived and a relation between coordinate of the peak and unknown parameters is given. Statistical characteristic of LFM signal with white noise in fractional Fourier domain is studied, a closed form expression is found for Signal-to-Noise Ratio(SNR), and it is compared with matched filter of ideal situation (i.e. parameters of LFM signal are known).
2007, 29(10): 2341-2345.
doi: 10.3724/SP.J.1146.2006.00268
Abstract:
A novel approach of radar target recognition is proposed in this paper. For each target class, according to maximum likelihood rule and minimum classification error rate rule, an optimal factor analysis subspace is constructed by factor analysis on the training sample sets of target rangeprofiles. The optimal factor analysis subspace can produce an enhancement of correlation existing in the features of same target class. Such an enhancement provides higher clustering degree of the same class features. Thus, the factor analysis subspace is used to extract the feature of target for improving the accuracy of classification. The experimental results of three kinds of airplane targets demonstrate the efficiency of the approach proposed in this paper.
A novel approach of radar target recognition is proposed in this paper. For each target class, according to maximum likelihood rule and minimum classification error rate rule, an optimal factor analysis subspace is constructed by factor analysis on the training sample sets of target rangeprofiles. The optimal factor analysis subspace can produce an enhancement of correlation existing in the features of same target class. Such an enhancement provides higher clustering degree of the same class features. Thus, the factor analysis subspace is used to extract the feature of target for improving the accuracy of classification. The experimental results of three kinds of airplane targets demonstrate the efficiency of the approach proposed in this paper.
2007, 29(10): 2346-2349.
doi: 10.3724/SP.J.1146.2006.00415
Abstract:
There is a growing interest in the Frequency Modulated Continuous Wave (FM-CW) SAR for its small cubage, light weight, cost-effective and high resolution. In this paper, the principle of the de-chirped FM-CW SAR is analyzed in detail, the phenomena, for example, Residual Visual Phase (RVP), Slope, range walk are discussed deeply, and the improved range Doppler imaging algorithm for the de-chirped FM-CW SAR is presented. The deduction and the simulation prove the algorithm is feasible and correct.
There is a growing interest in the Frequency Modulated Continuous Wave (FM-CW) SAR for its small cubage, light weight, cost-effective and high resolution. In this paper, the principle of the de-chirped FM-CW SAR is analyzed in detail, the phenomena, for example, Residual Visual Phase (RVP), Slope, range walk are discussed deeply, and the improved range Doppler imaging algorithm for the de-chirped FM-CW SAR is presented. The deduction and the simulation prove the algorithm is feasible and correct.
2007, 29(10): 2350-2353.
doi: 10.3724/SP.J.1146.2006.00264
Abstract:
The methods of data collection and miss distance measurement based on impulse radar are presented in this paper. The impulse radar collects return signal by range gates, which gets the data of distance corresponding every range gate and difference of impulse number betweem range getes. Then the miss distance can be estimated by fitting the collected data into conic. Simulations show that the measurement method has satisfying result for the parameter estimation of miss distance.
The methods of data collection and miss distance measurement based on impulse radar are presented in this paper. The impulse radar collects return signal by range gates, which gets the data of distance corresponding every range gate and difference of impulse number betweem range getes. Then the miss distance can be estimated by fitting the collected data into conic. Simulations show that the measurement method has satisfying result for the parameter estimation of miss distance.
2007, 29(10): 2354-2358.
doi: 10.3724/SP.J.1146.2006.00450
Abstract:
This paper proposes an non-cooperative target imaging technique based on the distributed multi-channel radar system, which consists of multiple sparsely-located transmitters and receivers. By coherently processing the signals received in multiple radar channels, the wave-number samples in a plane are obtained, from which the two-dimensional reflectivity function of target is reconstructed. Due to the simultaneous formation of multi-channel echo data and coherent processing of a single snap, it does not require large antennas, and the complicated motion compensation performed in ISAR imaging is not needed. Meanwhile, the reconstructed images are naturally scaled because the sampling locations in wave-number space are known. To validate the imaging performance, the distributed radar systems with wide-band transmitted signal are designed respectively, and the simulations are demonstrated.
This paper proposes an non-cooperative target imaging technique based on the distributed multi-channel radar system, which consists of multiple sparsely-located transmitters and receivers. By coherently processing the signals received in multiple radar channels, the wave-number samples in a plane are obtained, from which the two-dimensional reflectivity function of target is reconstructed. Due to the simultaneous formation of multi-channel echo data and coherent processing of a single snap, it does not require large antennas, and the complicated motion compensation performed in ISAR imaging is not needed. Meanwhile, the reconstructed images are naturally scaled because the sampling locations in wave-number space are known. To validate the imaging performance, the distributed radar systems with wide-band transmitted signal are designed respectively, and the simulations are demonstrated.
2007, 29(10): 2359-2362.
doi: 10.3724/SP.J.1146.2006.00475
Abstract:
The ENVISAT ASAR can operate on Alternating Polarization (AP) mode, which can provide three different dual polarization combinations. This paper derives target detectors for three different dual polarization combinations. The detection performance is compared using ROC curve. The results indicate that the Polarimetric Whiting Filter (PWF) detector is the best detector which approaches the performance of the ideal Optimized Polarimetric Detector (OPD) and can improve the detection performance.
The ENVISAT ASAR can operate on Alternating Polarization (AP) mode, which can provide three different dual polarization combinations. This paper derives target detectors for three different dual polarization combinations. The detection performance is compared using ROC curve. The results indicate that the Polarimetric Whiting Filter (PWF) detector is the best detector which approaches the performance of the ideal Optimized Polarimetric Detector (OPD) and can improve the detection performance.
2007, 29(10): 2363-2366.
doi: 10.3724/SP.J.1146.2006.00444
Abstract:
Considering the statistical independent property between phase and amplitude of SAR raw data, a new method is provided that the amplitude and phase of raw data are compressed respectively based on wavelet transform after a thorough analysis on the decomposed wavelets coefficients of the amplitude. By using the real SAR raw data, the performances achieved in terms of certain parameters are evaluated. The results show that this algorithm is superior to the traditional BAQ algorithm, simultaneously in terms of the reservation of phase information.
Considering the statistical independent property between phase and amplitude of SAR raw data, a new method is provided that the amplitude and phase of raw data are compressed respectively based on wavelet transform after a thorough analysis on the decomposed wavelets coefficients of the amplitude. By using the real SAR raw data, the performances achieved in terms of certain parameters are evaluated. The results show that this algorithm is superior to the traditional BAQ algorithm, simultaneously in terms of the reservation of phase information.
2007, 29(10): 2367-2370.
doi: 10.3724/SP.J.1146.2006.00321
Abstract:
Phase unwrapping is one of the key steps for the processing of InSAR data. The quality of the unwrapping results affects the final DEM (Digital Elevation Model) directly. In this paper, a new quality map is proposed. This new quality map reduces the affluence of the slope effect by plane-fitting and is denoted by the variance between the fitted plane and the original data. Also, an improved phase unwrapping method with a quality map is introduced in this paper. This new technique simplifies the route-searching processes by setting up a look-up table, which reduces the total processing time greatly. The experiment results with real InSAR data show that the proposed method is correct and effective.
Phase unwrapping is one of the key steps for the processing of InSAR data. The quality of the unwrapping results affects the final DEM (Digital Elevation Model) directly. In this paper, a new quality map is proposed. This new quality map reduces the affluence of the slope effect by plane-fitting and is denoted by the variance between the fitted plane and the original data. Also, an improved phase unwrapping method with a quality map is introduced in this paper. This new technique simplifies the route-searching processes by setting up a look-up table, which reduces the total processing time greatly. The experiment results with real InSAR data show that the proposed method is correct and effective.
2007, 29(10): 2371-2374.
doi: 10.3724/SP.J.1146.2006.00300
Abstract:
Cylindrical array antennas have three merits relative to common planar array antennas such as all-orientation space scanning, flexible search and track mode and good beam bearing etc. In this paper, firstly the differences between cylindrical array and uniform planar array are discussed in terms of eigenvalue distribution of the clutter covariance matrix and clutter distribution at range, and the conclusion of space-time clutter spectrums nonhomogeneity at range for airborne radar with cylindrical array antennas is gained. Secondly two different clutter suppression methods are proposed according to the clutter characteristic of airborne radar with cylindrical array antennas, which can resolve the problem of clutter spectrums nonhomogeneity at range. Finally, the simulation results verify the correctness of the proposed methods.
Cylindrical array antennas have three merits relative to common planar array antennas such as all-orientation space scanning, flexible search and track mode and good beam bearing etc. In this paper, firstly the differences between cylindrical array and uniform planar array are discussed in terms of eigenvalue distribution of the clutter covariance matrix and clutter distribution at range, and the conclusion of space-time clutter spectrums nonhomogeneity at range for airborne radar with cylindrical array antennas is gained. Secondly two different clutter suppression methods are proposed according to the clutter characteristic of airborne radar with cylindrical array antennas, which can resolve the problem of clutter spectrums nonhomogeneity at range. Finally, the simulation results verify the correctness of the proposed methods.
2007, 29(10): 2375-2378.
doi: 10.3724/SP.J.1146.2006.00256
Abstract:
A new motion compensation algorithm dealing with spatially variant phase error in azimuth direction is purposed in this article. Traditionally, only the spatially invariant part of phase error can be compensated and the residual spatially variant part is ignored. It is essential to compensate the spatially variant part of phase error in the high resolution wideband SAR. The new algorithm purposed in this article manages this part of phase error by splitting the SAR data to several sub-apertures in range-Doppler domain and compensates the spatially variant phase error respectively. The azimuth resolution is enhanced when the new algorithm is embedded into the traditional motion compensation algorithm.
A new motion compensation algorithm dealing with spatially variant phase error in azimuth direction is purposed in this article. Traditionally, only the spatially invariant part of phase error can be compensated and the residual spatially variant part is ignored. It is essential to compensate the spatially variant part of phase error in the high resolution wideband SAR. The new algorithm purposed in this article manages this part of phase error by splitting the SAR data to several sub-apertures in range-Doppler domain and compensates the spatially variant phase error respectively. The azimuth resolution is enhanced when the new algorithm is embedded into the traditional motion compensation algorithm.
2007, 29(10): 2379-2383.
doi: 10.3724/SP.J.1146.2006.00255
Abstract:
Aiming at airborne dual-antenna InSAR imaging, the characteristics of wavenumber domain imaging algorithms for master and slave antennas are analyzed. By introducing a range shift factor and a range scaling factor in range direction, a wavenumber domain imaging algorithm with completing registration during the course of imaging is presented. By means of computer simulation and processing practical InSAR data, the algorithm is demonstrated in completing registration between a pair of complex images during the course of processing original echoes data for airborne dual-antenna InSAR imaging.
Aiming at airborne dual-antenna InSAR imaging, the characteristics of wavenumber domain imaging algorithms for master and slave antennas are analyzed. By introducing a range shift factor and a range scaling factor in range direction, a wavenumber domain imaging algorithm with completing registration during the course of imaging is presented. By means of computer simulation and processing practical InSAR data, the algorithm is demonstrated in completing registration between a pair of complex images during the course of processing original echoes data for airborne dual-antenna InSAR imaging.
2007, 29(10): 2384-2387.
doi: 10.3724/SP.J.1146.2006.00404
Abstract:
Air- or vehicle-borne Ultra-WideBand Synthetic Aperture Radar (UWB SAR) can detect landmines or minefields over large area quickly, which is a trend of landmine detection. Traditional image formations, based on even medium assumption, are not suitable to the subsurface target imaging. In this paper, a subsurface target echo model is firstly developed to analyze the refraction and dispersion effects on imaging quantitatively. Based on the model, Subsurface Back-Projection (SBP) image formation is used to compensate the refraction and dispersion effects in echo domain and image domain, respectively. Unfortunately, prior knowledge of target buried depth and incident angle cannot be obtained in landmine detection over undiscovered areas. In order to solve the problem, a hierarchical processing procedure with coarse and fine compensation is proposed on SBP image formation in image domain, which realizes multi-target focusing and locating over wide areas. Finally, the proposed methods are verified using real data collected with the Rail-GPSAR landmine detection experimental system.
Air- or vehicle-borne Ultra-WideBand Synthetic Aperture Radar (UWB SAR) can detect landmines or minefields over large area quickly, which is a trend of landmine detection. Traditional image formations, based on even medium assumption, are not suitable to the subsurface target imaging. In this paper, a subsurface target echo model is firstly developed to analyze the refraction and dispersion effects on imaging quantitatively. Based on the model, Subsurface Back-Projection (SBP) image formation is used to compensate the refraction and dispersion effects in echo domain and image domain, respectively. Unfortunately, prior knowledge of target buried depth and incident angle cannot be obtained in landmine detection over undiscovered areas. In order to solve the problem, a hierarchical processing procedure with coarse and fine compensation is proposed on SBP image formation in image domain, which realizes multi-target focusing and locating over wide areas. Finally, the proposed methods are verified using real data collected with the Rail-GPSAR landmine detection experimental system.
2007, 29(10): 2388-2391.
doi: 10.3724/SP.J.1146.2006.00002
Abstract:
A Kalman filter positioning algorithm applied in BeiDou and INS integrated navigation system is proposed. Then, the observability, controllability and stability of integrated navigation filter algorithm is analyzed. The observability of every state is analyzed using method of numerical value analysis. Because the clock-error state can not be filtered, otherwise the algorithm may be divergence, we make improvement on the filter algorithm model, using the change rate of pseudo-ranges and INSs acceleration as observations. Finally, it is explained in emulation mode that our improved integrated navigation algorithm model can improve the running stability of integrated navigation system effectively, its ability of resisting outburst error is enhanced effectively, and the clock-error state can be filtered even when the original location error is up to 13000 meter.
A Kalman filter positioning algorithm applied in BeiDou and INS integrated navigation system is proposed. Then, the observability, controllability and stability of integrated navigation filter algorithm is analyzed. The observability of every state is analyzed using method of numerical value analysis. Because the clock-error state can not be filtered, otherwise the algorithm may be divergence, we make improvement on the filter algorithm model, using the change rate of pseudo-ranges and INSs acceleration as observations. Finally, it is explained in emulation mode that our improved integrated navigation algorithm model can improve the running stability of integrated navigation system effectively, its ability of resisting outburst error is enhanced effectively, and the clock-error state can be filtered even when the original location error is up to 13000 meter.
2007, 29(10): 2392-2395.
doi: 10.3724/SP.J.1146.2006.00245
Abstract:
A CPW-fed slot-coupled millimeter wave (Ka band) patch antenna is discussed. The coupling slot is on the ground plane, hence there is no need for a couple slot layer. The presence of the coupling slot changes the current distribution on the ground plane, and the current is guided by the slot, the coupling between the feed part and the radiation part is enhanced. Ansoft HFSS, a high frequency structure simulation software based on Finite Element Method (FEM), is used to analyze the antenna performances. Variations of parameters such as: substrate thickness, bow-tie patch angle, coupling slot size, etc. are discussed. A set of parameters is given after comparing and analyzing the simulation results, such as S11 and gain of the antenna. The antenna works at the center frequency of 35.5GHz, the bandwidth is 1.22GHz, and the gain is 6.38dB.
A CPW-fed slot-coupled millimeter wave (Ka band) patch antenna is discussed. The coupling slot is on the ground plane, hence there is no need for a couple slot layer. The presence of the coupling slot changes the current distribution on the ground plane, and the current is guided by the slot, the coupling between the feed part and the radiation part is enhanced. Ansoft HFSS, a high frequency structure simulation software based on Finite Element Method (FEM), is used to analyze the antenna performances. Variations of parameters such as: substrate thickness, bow-tie patch angle, coupling slot size, etc. are discussed. A set of parameters is given after comparing and analyzing the simulation results, such as S11 and gain of the antenna. The antenna works at the center frequency of 35.5GHz, the bandwidth is 1.22GHz, and the gain is 6.38dB.
2007, 29(10): 2396-2400.
doi: 10.3724/SP.J.1146.2006.00455
Abstract:
Based on the fact that there exist several subband signals in the received bandwidth, whose number, band location and bandwidth are time-variant, this paper presents an efficient method of dynamic channelization based on nonuniform filterbanks. The number of subchannels of the uniform filterbank is firstly determined by the given minimal guard bandwidth, and then a corresponding cosine-based filterbank is designed. A nonuniform matrix is derived in terms of band location of every subband signal, and then a nonuniform filterbank can be constructed through directly merging the adjacent subchannels of the uniform filterbank according to the nonuniform matrix. When subband signals dynamically change, channelization can be implemented as long as updating the nonuniform matrix in terms of band location of new subband signal. The computational complexity of implementation architecture can be reduced by the use of relationships between decimation factors of different subband signals. Computer simulations illustrate new method validity.
Based on the fact that there exist several subband signals in the received bandwidth, whose number, band location and bandwidth are time-variant, this paper presents an efficient method of dynamic channelization based on nonuniform filterbanks. The number of subchannels of the uniform filterbank is firstly determined by the given minimal guard bandwidth, and then a corresponding cosine-based filterbank is designed. A nonuniform matrix is derived in terms of band location of every subband signal, and then a nonuniform filterbank can be constructed through directly merging the adjacent subchannels of the uniform filterbank according to the nonuniform matrix. When subband signals dynamically change, channelization can be implemented as long as updating the nonuniform matrix in terms of band location of new subband signal. The computational complexity of implementation architecture can be reduced by the use of relationships between decimation factors of different subband signals. Computer simulations illustrate new method validity.
2007, 29(10): 2401-2404.
doi: 10.3724/SP.J.1146.2006.00233
Abstract:
Focusing on the problem that existing Space-Time Frequency-Shift Keying (ST-FSK) incurs a spectral efficiency loss, this paper proposes a novel ST-FSK based on Hadamard matrix modulation coined as HST-FSK. HST-FSK uses the Hadamard matrix to expand a newly defined FSK waveform in both spatial and temporal dimensions according to the Kronecker product, and it achieves a higher spectral efficiency than ST-FSK owing to the more parameters are introduced into the new FSK waveform. As a special unitary space-time code, HST-FSK is appropriate for arbitrary number of transmit antennas and can be non-coherently detected with the absent of Channel State Information (CSI) at the receiver. Moreover, HST-FSK is easier to design and enjoys full antenna diversity, which are the advantages of HST-FSK over other Unitary Space-Time Modulation (USTM) designs. Theoretical analysis and simulation results show that compared with the existing typical USTM schemes, HST-FSK achieves a performance comparable to ST-FSK for the same spectral efficiency, and a better performance than the systematic designed USTM for high spectral efficiency.
Focusing on the problem that existing Space-Time Frequency-Shift Keying (ST-FSK) incurs a spectral efficiency loss, this paper proposes a novel ST-FSK based on Hadamard matrix modulation coined as HST-FSK. HST-FSK uses the Hadamard matrix to expand a newly defined FSK waveform in both spatial and temporal dimensions according to the Kronecker product, and it achieves a higher spectral efficiency than ST-FSK owing to the more parameters are introduced into the new FSK waveform. As a special unitary space-time code, HST-FSK is appropriate for arbitrary number of transmit antennas and can be non-coherently detected with the absent of Channel State Information (CSI) at the receiver. Moreover, HST-FSK is easier to design and enjoys full antenna diversity, which are the advantages of HST-FSK over other Unitary Space-Time Modulation (USTM) designs. Theoretical analysis and simulation results show that compared with the existing typical USTM schemes, HST-FSK achieves a performance comparable to ST-FSK for the same spectral efficiency, and a better performance than the systematic designed USTM for high spectral efficiency.
A Novel Algorithm Based on Asymmetric-Nash-Bargain-Solution for Spectrum Sharing in Cognitive Radios
2007, 29(10): 2405-2409.
doi: 10.3724/SP.J.1146.2006.01276
Abstract:
A new scheme to share spectrum employing MIMO-OFDMA-based Cognitive Radio (CR) is proposed. First an Asymmetric-Nash-Bargain-Solution (ANBS)-based utility function is developed. And a new spectrum sharing algorithm based on sensing contribution weighted proportional fairness is implemented through multi-users optimal matching and two users bargaining. The experimental results show that the approach not only realizes efficient and fair allocation of the spectrum resources but also maximizes the potential of the spectrum sensing.
A new scheme to share spectrum employing MIMO-OFDMA-based Cognitive Radio (CR) is proposed. First an Asymmetric-Nash-Bargain-Solution (ANBS)-based utility function is developed. And a new spectrum sharing algorithm based on sensing contribution weighted proportional fairness is implemented through multi-users optimal matching and two users bargaining. The experimental results show that the approach not only realizes efficient and fair allocation of the spectrum resources but also maximizes the potential of the spectrum sensing.
2007, 29(10): 2410-2413.
doi: 10.3724/SP.J.1146.2006.00588
Abstract:
Carrier Frequency offsets in OFDMA system will introduce InterCarrier Interference (ICI) and consequently degrade the system performance. A new frequency offset estimation algorithm for OFDMA system based on the combination of ESPRIT (Estimation of Signal Parameters by Rotational Invariance Techniques) and the Maximum Likelihood (ML) estimation method is proposed. The subset of the frequency offsets first is estimated by ESPRIT, then the frequency offset of each user is identified in the subset by the ML estimation method. The algorithm greatly decreases the complexity of N-dimensional search processes of ML method and efficiently solves the problem of multi-frequency offsets estimation.
Carrier Frequency offsets in OFDMA system will introduce InterCarrier Interference (ICI) and consequently degrade the system performance. A new frequency offset estimation algorithm for OFDMA system based on the combination of ESPRIT (Estimation of Signal Parameters by Rotational Invariance Techniques) and the Maximum Likelihood (ML) estimation method is proposed. The subset of the frequency offsets first is estimated by ESPRIT, then the frequency offset of each user is identified in the subset by the ML estimation method. The algorithm greatly decreases the complexity of N-dimensional search processes of ML method and efficiently solves the problem of multi-frequency offsets estimation.
2007, 29(10): 2414-2417.
doi: 10.3724/SP.J.1146.2006.00364
Abstract:
A calibration algorithm of two-slope propagation model based on the recursive LLSM is expatiated in this paper to improve the accuracy of the propagation loss prediction in wireless network planning, and to improve the practicability of the two-slope propagation model. A comparison between the results of the calibrations of two-slope propagation model and single-slope propagation model is also presented, which proves the better performance of the former.
A calibration algorithm of two-slope propagation model based on the recursive LLSM is expatiated in this paper to improve the accuracy of the propagation loss prediction in wireless network planning, and to improve the practicability of the two-slope propagation model. A comparison between the results of the calibrations of two-slope propagation model and single-slope propagation model is also presented, which proves the better performance of the former.
2007, 29(10): 2418-2421.
doi: 10.3724/SP.J.1146.2006.00367
Abstract:
In future mobile system some independent handsets can obtain the benefits of cooperative diversity by the way of cooperative transmission. At the same time, information exchange error will degrade the performance of cooperative transmission. Considering Rayleigh fading channel and the cooperative transmit scheme based on STBC, the effect of information exchange error on cooperative diversity is researched. Finally, the theory analysis and simulation results show that when the SNR is high information exchange error becomes the main factor that degrades the reception performance, if the number of cooperative handsets is more than two, increasing the number of reception antennas can improve the reception performance boundary in some degree.
In future mobile system some independent handsets can obtain the benefits of cooperative diversity by the way of cooperative transmission. At the same time, information exchange error will degrade the performance of cooperative transmission. Considering Rayleigh fading channel and the cooperative transmit scheme based on STBC, the effect of information exchange error on cooperative diversity is researched. Finally, the theory analysis and simulation results show that when the SNR is high information exchange error becomes the main factor that degrades the reception performance, if the number of cooperative handsets is more than two, increasing the number of reception antennas can improve the reception performance boundary in some degree.
2007, 29(10): 2422-2425.
doi: 10.3724/SP.J.1146.2006.00311
Abstract:
For construct a high-rate and low-delay Complex Orthogonal Space-Time Block Codes (COSTBC) matrix, this paper presents an iterative design method without linear processing of symbols to generate high-rate and low-delay COSTBC matrix. By the orthogonality of symbols, a simple maximum likelihood-decoding algorithm is used to recover them at the receiver accurately. By the help of computer, the data of the matrix are got. The results of compare the data with that from others matrix shows the matrix is a closed-form design of high-rate and low-delay.
For construct a high-rate and low-delay Complex Orthogonal Space-Time Block Codes (COSTBC) matrix, this paper presents an iterative design method without linear processing of symbols to generate high-rate and low-delay COSTBC matrix. By the orthogonality of symbols, a simple maximum likelihood-decoding algorithm is used to recover them at the receiver accurately. By the help of computer, the data of the matrix are got. The results of compare the data with that from others matrix shows the matrix is a closed-form design of high-rate and low-delay.
2007, 29(10): 2426-2430.
doi: 10.3724/SP.J.1146.2006.01440
Abstract:
This paper firstly introduces a new architecture of adding the relay function to cellular systems in the dead spots, and describes the systems analytical model under this environment. Then based on this model, the call outage probability of this cellular system with relaying can be derived with mathematical analyzing. Finally, through numerical calculation and performance comparison, the cellular system with relaying can be provided to attain more lower call outage probability than that of the traditional cellular system without relaying under the environment of dead spots, and the impact of the velocity, average call duration and radius of the mobile station on the performances of these two different cellular systems is also analyzed.
This paper firstly introduces a new architecture of adding the relay function to cellular systems in the dead spots, and describes the systems analytical model under this environment. Then based on this model, the call outage probability of this cellular system with relaying can be derived with mathematical analyzing. Finally, through numerical calculation and performance comparison, the cellular system with relaying can be provided to attain more lower call outage probability than that of the traditional cellular system without relaying under the environment of dead spots, and the impact of the velocity, average call duration and radius of the mobile station on the performances of these two different cellular systems is also analyzed.
2007, 29(10): 2431-2435.
doi: 10.3724/SP.J.1146.2006.00383
Abstract:
Reducing the Peak-to-Average Power Ratio(PAPR) is one of the key technologies in MC-CDMA system. This paper derived the PAPR properties of MC-CDMA signal using orthogonal complementary spreading codes, constructed the polyphase spreading codes for MC-CDMA system using the polyphase pulse compression codes, and proved that they belonged to orthogonal complementary codes. The simulation results showed that under various modulation schemes, most polyphase pulse compression spreading codes could reduce PAPR when compared to traditional codes, especially under the multiple level modulation schemes and in different user number cases, polyphase spreading codes are good choices for MC-CDMA system.
Reducing the Peak-to-Average Power Ratio(PAPR) is one of the key technologies in MC-CDMA system. This paper derived the PAPR properties of MC-CDMA signal using orthogonal complementary spreading codes, constructed the polyphase spreading codes for MC-CDMA system using the polyphase pulse compression codes, and proved that they belonged to orthogonal complementary codes. The simulation results showed that under various modulation schemes, most polyphase pulse compression spreading codes could reduce PAPR when compared to traditional codes, especially under the multiple level modulation schemes and in different user number cases, polyphase spreading codes are good choices for MC-CDMA system.
2007, 29(10): 2436-2440.
doi: 10.3724/SP.J.1146.2006.00265
Abstract:
The principle of multi-user chaotic sequence spread-spectrum communication system is introduced. Performances of balance and correlation properties of three different chaotic spread series (Chebyshev, Logistic and Tent) are analyzed. The dynamic visual simulation modeling of multi-user chaotic sequence spread-spectrum communication system is established. Based on this modeling, the error-bit rate performances of these systems with different initial values, signal to noise ratio, number of users and the length of sequence are investigated. Simulation results show that the spread-spectrum performance of Chebyshev is the best, then Logistic and Tent, and the spread-spectrum performances of the three chaotic spread series are better than that of the conventional spread sequence.
The principle of multi-user chaotic sequence spread-spectrum communication system is introduced. Performances of balance and correlation properties of three different chaotic spread series (Chebyshev, Logistic and Tent) are analyzed. The dynamic visual simulation modeling of multi-user chaotic sequence spread-spectrum communication system is established. Based on this modeling, the error-bit rate performances of these systems with different initial values, signal to noise ratio, number of users and the length of sequence are investigated. Simulation results show that the spread-spectrum performance of Chebyshev is the best, then Logistic and Tent, and the spread-spectrum performances of the three chaotic spread series are better than that of the conventional spread sequence.
2007, 29(10): 2441-2443.
doi: 10.3724/SP.J.1146.2006.00412
Abstract:
The analytical method of shift sequences is presented comparing to the traditional algorithm which is used to compute correlation values originally, so a new algorithm for computing correlation values is gotten. Using the algorithm, it is analysed the correlation value of the phase-controlled sequences in theory, the result is consistent with the original result, so correctness of the algorithm is proved; At the same time the comparison of the new algorithm and original algorithm between some sequences with different length is presented, so it is clear to see the former is more faster. Therefore using this algorithm can not only fast compute a lot of known sequences and get the sequences families with ideal correlation value but also can get the correlation value of the constructed new sequences and can see whether they are up to the mustard, then estimate whether they can be applied into the corresponding system or not.
The analytical method of shift sequences is presented comparing to the traditional algorithm which is used to compute correlation values originally, so a new algorithm for computing correlation values is gotten. Using the algorithm, it is analysed the correlation value of the phase-controlled sequences in theory, the result is consistent with the original result, so correctness of the algorithm is proved; At the same time the comparison of the new algorithm and original algorithm between some sequences with different length is presented, so it is clear to see the former is more faster. Therefore using this algorithm can not only fast compute a lot of known sequences and get the sequences families with ideal correlation value but also can get the correlation value of the constructed new sequences and can see whether they are up to the mustard, then estimate whether they can be applied into the corresponding system or not.
2007, 29(10): 2444-2447.
doi: 10.3724/SP.J.1146.2006.00232
Abstract:
A single-pass frame-level Constant-SNR Bit Allocation (CSNRBA) scheme is developed for video quality smoothing throughout the video sequence in this paper. A power series weighted actual SNR average of previous coded frames is adopted as the target SNR for the current frame. According to the newly developed analytic close-form D-Q model and the linear rate control algorithm, the bit budget can be estimated. Experimental results show that the proposed CSNRBA scheme provides much smoother video quality and achieves much better subjective video quality in terms of natural color, sharp objects and silhouette significantly on all testing video sequences than both constant bit allocation and constant PSNR bit allocation schemes.
A single-pass frame-level Constant-SNR Bit Allocation (CSNRBA) scheme is developed for video quality smoothing throughout the video sequence in this paper. A power series weighted actual SNR average of previous coded frames is adopted as the target SNR for the current frame. According to the newly developed analytic close-form D-Q model and the linear rate control algorithm, the bit budget can be estimated. Experimental results show that the proposed CSNRBA scheme provides much smoother video quality and achieves much better subjective video quality in terms of natural color, sharp objects and silhouette significantly on all testing video sequences than both constant bit allocation and constant PSNR bit allocation schemes.
2007, 29(10): 2448-2450.
doi: 10.3724/SP.J.1146.2006.00340
Abstract:
This paper analyzes the security of the Naccache-Stern public key cryptosystem by providing an attack. The basic idea of the attack is that the decryption of the cryptosystem can be viewed as a group factorization problem and the solution to the problem gives rise to an equivalent plaintext. It is also shown that if all the entries of the equivalent plaintext vector are small enough, the equivalent plaintext is the exact plaintext corresponding to the ciphertext. In general, the success probability of the proposed attack is much higher than that of solving the discrete logarithm problem directly. The success probability of the attack relies on with what probability it can successfully transform a random integer into a smooth number.
This paper analyzes the security of the Naccache-Stern public key cryptosystem by providing an attack. The basic idea of the attack is that the decryption of the cryptosystem can be viewed as a group factorization problem and the solution to the problem gives rise to an equivalent plaintext. It is also shown that if all the entries of the equivalent plaintext vector are small enough, the equivalent plaintext is the exact plaintext corresponding to the ciphertext. In general, the success probability of the proposed attack is much higher than that of solving the discrete logarithm problem directly. The success probability of the attack relies on with what probability it can successfully transform a random integer into a smooth number.
2007, 29(10): 2451-2454.
doi: 10.3724/SP.J.1146.2006.00397
Abstract:
This paper designs ffgg★protocol which is similar toffggprotocol constructed by Millen.They have cryptographic properties in commen. Then,the protocol is analyzed by using constructing attack based on generalized strand space model ,and it is proved that the protocol is secure under non-type-flaw attacks .After ffggprotocol is analyzed by Millen using Pulson`s inductive approach,it is secure under non-type-flaw attacks,either. It is indicated that constructing attack has limitation. Finally,some improved measures are put forward,and type-flaw attack is found by using amendatory constructing attack inffgg★protocol.
This paper designs ffgg★protocol which is similar toffggprotocol constructed by Millen.They have cryptographic properties in commen. Then,the protocol is analyzed by using constructing attack based on generalized strand space model ,and it is proved that the protocol is secure under non-type-flaw attacks .After ffggprotocol is analyzed by Millen using Pulson`s inductive approach,it is secure under non-type-flaw attacks,either. It is indicated that constructing attack has limitation. Finally,some improved measures are put forward,and type-flaw attack is found by using amendatory constructing attack inffgg★protocol.
2007, 29(10): 2455-2459.
doi: 10.3724/SP.J.1146.2006.00329
Abstract:
According to the multi-protected mechanism of the immune system and the immune principles, such as the antigen recognition, immune study, co-stimulation, clone selection and negative selection, an immunology-based multi-protected detection method of the feature interaction is proposed to detect the known and unknown feature interactions gradually. The simulation and research show that this method can detect all kinds of service interaction with high detection ratio and efficiency, expansibility, adaptability.
According to the multi-protected mechanism of the immune system and the immune principles, such as the antigen recognition, immune study, co-stimulation, clone selection and negative selection, an immunology-based multi-protected detection method of the feature interaction is proposed to detect the known and unknown feature interactions gradually. The simulation and research show that this method can detect all kinds of service interaction with high detection ratio and efficiency, expansibility, adaptability.
2007, 29(10): 2460-2465.
doi: 10.3724/SP.J.1146.2006.00308
Abstract:
Web Services-based Services Management Protocol(WSSMP) is proposed, through which, services across different management domains can be efficiently managed. With Petri net, a formalized description of the protocol model is given. Moreover, the logical correctness of the protocol is verified through the analyses of the reachability of Petri net, thus making sure the boundedness, liveliness, completeness and advancement of the protocol. Thereby, the potential mistakes in protocol design are reduced. Emulation of the protocol is given. The results show that, when a large number of objects are retrieved, the bandwidth consumption of compressed WSSMP increases slowly as the number of retrieved objects increases. Accordingly, the protocol is adapted to large bandwidth requirement of service management.
Web Services-based Services Management Protocol(WSSMP) is proposed, through which, services across different management domains can be efficiently managed. With Petri net, a formalized description of the protocol model is given. Moreover, the logical correctness of the protocol is verified through the analyses of the reachability of Petri net, thus making sure the boundedness, liveliness, completeness and advancement of the protocol. Thereby, the potential mistakes in protocol design are reduced. Emulation of the protocol is given. The results show that, when a large number of objects are retrieved, the bandwidth consumption of compressed WSSMP increases slowly as the number of retrieved objects increases. Accordingly, the protocol is adapted to large bandwidth requirement of service management.
2007, 29(10): 2466-2470.
doi: 10.3724/SP.J.1146.2006.00467
Abstract:
The 802.11MAC protocol has been used widely in static multihop wireless network. It reduces the effect of hidden terminal for TCP performance, but it does not remove the effect of hidden terminal fully. But, the fairness of middle links will be affected due to the hidden terminal and make the throughput badly descend. This paper proposes a new way based on data retransfer ratio. When the data retransfer ratio increase, dynamic reduce the size of contention window of backofftimer, enhance the probability of use channel and improvement the TCP fairness. The simulational results show that the proposed algorithm can ultimately avoid the instability of TCP flow and increase the fairness of middle links.
The 802.11MAC protocol has been used widely in static multihop wireless network. It reduces the effect of hidden terminal for TCP performance, but it does not remove the effect of hidden terminal fully. But, the fairness of middle links will be affected due to the hidden terminal and make the throughput badly descend. This paper proposes a new way based on data retransfer ratio. When the data retransfer ratio increase, dynamic reduce the size of contention window of backofftimer, enhance the probability of use channel and improvement the TCP fairness. The simulational results show that the proposed algorithm can ultimately avoid the instability of TCP flow and increase the fairness of middle links.
2007, 29(10): 2471-2476.
doi: 10.3724/SP.J.1146.2006.00270
Abstract:
In the IMS(IP Multimedia Subsystem) specification of UMTS(Universal Mobile Telecommunications System) R6, the user must register its location in its home registrar. The session signaling have to reach its home registrar when user is not in home network, which results in the session path longer than the media path and defining the users to its home services. A new location management schedule and an auto-adjustable caching algorithm are proposed, so that the session signaling need not pass the home registrar but directly from original users visited network to terminate users network. The results of Simulation and analysis shows the new schedule get the benefit in cost and time.
In the IMS(IP Multimedia Subsystem) specification of UMTS(Universal Mobile Telecommunications System) R6, the user must register its location in its home registrar. The session signaling have to reach its home registrar when user is not in home network, which results in the session path longer than the media path and defining the users to its home services. A new location management schedule and an auto-adjustable caching algorithm are proposed, so that the session signaling need not pass the home registrar but directly from original users visited network to terminate users network. The results of Simulation and analysis shows the new schedule get the benefit in cost and time.
2007, 29(10): 2477-2481.
doi: 10.3724/SP.J.1146.2006.00249
Abstract:
Secure multicast uses a group key shared by all group members to encrypt group communication. To ensure security, key server should update the group key (rekey) when an existing member leaves the group or a new member joins the group. Key tree approach is widely used to achieve logarithmic rekeying cost, but the key tree structure has to be kept balanced, otherwise the communication cost in the worst cast will be O(n). In this article a new algorithm named PSA (Path Shuffling Algorithm) is proposed based on key tree. PSA can scatter the balanced operations in normal rekeying operations, so it reduces the restructuring cost and thus improves the performance. Theoretical analysis gives the average updating cost, and experiments show that PSA algorithm has better average-case rekeying performance than other group key updating algorithms.
Secure multicast uses a group key shared by all group members to encrypt group communication. To ensure security, key server should update the group key (rekey) when an existing member leaves the group or a new member joins the group. Key tree approach is widely used to achieve logarithmic rekeying cost, but the key tree structure has to be kept balanced, otherwise the communication cost in the worst cast will be O(n). In this article a new algorithm named PSA (Path Shuffling Algorithm) is proposed based on key tree. PSA can scatter the balanced operations in normal rekeying operations, so it reduces the restructuring cost and thus improves the performance. Theoretical analysis gives the average updating cost, and experiments show that PSA algorithm has better average-case rekeying performance than other group key updating algorithms.
2007, 29(10): 2482-2486.
doi: 10.3724/SP.J.1146.2006.00260
Abstract:
A major application level task in wireless sensor network operation is the formation of an adaptive local network, and the sensing data from sensors are gathered at a central node for various cooperative signal processing functions. Based on mutual information theory, the overhead different central node election scheme is analyzed, and demonstrate diffusing computing election is more overhead efficient. An Adaptive Cooperative Communication Routing Protocol (ACCRP) is proposed: nodes select central node and construct route in distributed manner. The proof of correctness about ACCRP is presented. The performance of ACCRP is tested by simulation. The simulation results indicate that ACCRP is energy efficient, scalable and adaptive.
A major application level task in wireless sensor network operation is the formation of an adaptive local network, and the sensing data from sensors are gathered at a central node for various cooperative signal processing functions. Based on mutual information theory, the overhead different central node election scheme is analyzed, and demonstrate diffusing computing election is more overhead efficient. An Adaptive Cooperative Communication Routing Protocol (ACCRP) is proposed: nodes select central node and construct route in distributed manner. The proof of correctness about ACCRP is presented. The performance of ACCRP is tested by simulation. The simulation results indicate that ACCRP is energy efficient, scalable and adaptive.
2007, 29(10): 2487-2492.
doi: 10.3724/SP.J.1146.2006.00618
Abstract:
Identifying and measuring large flows is an important scalable solution for traffic measuring accurately on high-speed networks. A new algorithm based on LRU replacement scheme is proposed, which uses the policies of early dropping small flows and preparatively protecting large flows to enhance the accuracy of traffic measurement. An analysis demonstrates that the new algorithm can support the 10Gbps line-speed processing. Experiments are also conducted based on real network traces. Results show that the proposed method is more accurate and practicable than existing algorithms.
Identifying and measuring large flows is an important scalable solution for traffic measuring accurately on high-speed networks. A new algorithm based on LRU replacement scheme is proposed, which uses the policies of early dropping small flows and preparatively protecting large flows to enhance the accuracy of traffic measurement. An analysis demonstrates that the new algorithm can support the 10Gbps line-speed processing. Experiments are also conducted based on real network traces. Results show that the proposed method is more accurate and practicable than existing algorithms.
2007, 29(10): 2493-2497.
doi: 10.3724/SP.J.1146.2006.00384
Abstract:
For the description of the nondeterministic factors in the non-repudiation protocols, the Kailar logic system extended with the default negation and the corresponding reasoning mechanism is introduced. The extended system can be used to verify security protocols and it has several main characteristics. Firstly, the method can reason not only for the results but also for the dynamic procedure of the protocol run. Secondly, the reasoning is nonmonotonic. Thirdly, the ideal assumptions of the protocols can be reduced. Fourthly, the accountability and fairness of the security protocols with some sub-protocols can be analyzed. As an example, a non-repudiation protocol with offline TTP was verified. The protocol has accountability during one protocol run and gets the attack in the repeated runs.
For the description of the nondeterministic factors in the non-repudiation protocols, the Kailar logic system extended with the default negation and the corresponding reasoning mechanism is introduced. The extended system can be used to verify security protocols and it has several main characteristics. Firstly, the method can reason not only for the results but also for the dynamic procedure of the protocol run. Secondly, the reasoning is nonmonotonic. Thirdly, the ideal assumptions of the protocols can be reduced. Fourthly, the accountability and fairness of the security protocols with some sub-protocols can be analyzed. As an example, a non-repudiation protocol with offline TTP was verified. The protocol has accountability during one protocol run and gets the attack in the repeated runs.
2007, 29(10): 2498-2503.
doi: 10.3724/SP.J.1146.2006.00272
Abstract:
With boosting of stream media applications, content-based media information retrieval becomes hot topic of current academic research. Since news program is familiar and popular, topic retrieval of news program has important practical significance. Based on audio processing, this paper integrates studio / non-studio classification, speaker change detection and speaker clustering, and realizes automatic news topic retrieval and clustering according to anchorman. The experiment indicates that above 96% studio segments of news programs can be found out and clustered, and proves feasibility and potential of the method.
With boosting of stream media applications, content-based media information retrieval becomes hot topic of current academic research. Since news program is familiar and popular, topic retrieval of news program has important practical significance. Based on audio processing, this paper integrates studio / non-studio classification, speaker change detection and speaker clustering, and realizes automatic news topic retrieval and clustering according to anchorman. The experiment indicates that above 96% studio segments of news programs can be found out and clustered, and proves feasibility and potential of the method.
2007, 29(10): 2504-2507.
doi: 10.3724/SP.J.1146.2006.00353
Abstract:
In this paper a wireless packet transmission scheme over Multiple Input Multiple Output (MIMO) Gaussian Broadcast Channel (GBC) is proposed. Specifically, the transmission packet delay constraint and broadcast channel capacity are considered jointly, based on QR decomposition of channel and Dirty Paper Coding (DPC), a greedy algorithm is used to exploit multiuser diversity as well as transmission packet delay constraint in base station. It demonstrates that the packet arrival rate, achievable service rate, user number and transmitting antenna number can be formulated into an optimization problem. The simulation results show that the proposed scheme can maximize the system throughput, while providing guarantees on delay performance.
In this paper a wireless packet transmission scheme over Multiple Input Multiple Output (MIMO) Gaussian Broadcast Channel (GBC) is proposed. Specifically, the transmission packet delay constraint and broadcast channel capacity are considered jointly, based on QR decomposition of channel and Dirty Paper Coding (DPC), a greedy algorithm is used to exploit multiuser diversity as well as transmission packet delay constraint in base station. It demonstrates that the packet arrival rate, achievable service rate, user number and transmitting antenna number can be formulated into an optimization problem. The simulation results show that the proposed scheme can maximize the system throughput, while providing guarantees on delay performance.
2007, 29(10): 2508-2511.
doi: 10.3724/SP.J.1146.2006.00310
Abstract:
In this paper a newly-proposed Liu chaotic system(2004) is synchronized by using fuzzy feedback method. The structure of Liu chaotic system is different from other linear chaotic systems. Firstly based on T-S(Takagi-Sugeno) fuzzy model, Liu chaotic system is reconstructed. Secondly, using Lyapunov theory and feedback synchronization concept, the stability synchronization conditions of two reconstructed Liu systems are deduced. Moreover to the error system with the decay rate , sufficient conditions of global asymptotic stability are given. Finally, satisfied simulation results based on Llinear Mmatrix Iinequality (LMI) method show the effectiveness and quickness of fuzzy feedback method proposed in this paper.
In this paper a newly-proposed Liu chaotic system(2004) is synchronized by using fuzzy feedback method. The structure of Liu chaotic system is different from other linear chaotic systems. Firstly based on T-S(Takagi-Sugeno) fuzzy model, Liu chaotic system is reconstructed. Secondly, using Lyapunov theory and feedback synchronization concept, the stability synchronization conditions of two reconstructed Liu systems are deduced. Moreover to the error system with the decay rate , sufficient conditions of global asymptotic stability are given. Finally, satisfied simulation results based on Llinear Mmatrix Iinequality (LMI) method show the effectiveness and quickness of fuzzy feedback method proposed in this paper.
2007, 29(10): 2512-2516.
doi: 10.3724/SP.J.1146.2006.00263
Abstract:
A modeling of 2.45GHz low-power microwave plasma source based on a microstrip split-ring resonator is presented in this paper. According to characteristics of half-wavelength resonator with a open circuit at the end, the parameters such as discharge gap, angular position of the feeding point and permittivity of dielectric substrate are optimized to make the quality factor of microstrip split-ring resonator reach maximum and match the input impedance of the resonator to that of the power supply. The research indicates that experimental results are found to be in good agreement with simulated results. The theoretical basis is gained for further research of low-power microwave microplasma.
A modeling of 2.45GHz low-power microwave plasma source based on a microstrip split-ring resonator is presented in this paper. According to characteristics of half-wavelength resonator with a open circuit at the end, the parameters such as discharge gap, angular position of the feeding point and permittivity of dielectric substrate are optimized to make the quality factor of microstrip split-ring resonator reach maximum and match the input impedance of the resonator to that of the power supply. The research indicates that experimental results are found to be in good agreement with simulated results. The theoretical basis is gained for further research of low-power microwave microplasma.
2007, 29(10): 2517-2520.
doi: 10.3724/SP.J.1146.2006.00298
Abstract:
Coupling of higher order transverse magnetic modes TM310 in microwave coaxial cavity of klystron with TE10 mode of rectangular waveguide is analyzed based on power-voltage and LC equivalent-circuit methods respectively. Gap impedances of output cavity were calculated by using of electromagnetic fields which was point-by-point took out from PAC3D of software ISFEL3D. Results obtained in the two methods made an agreement. It is found that larger gap impedance can be obtained by employing calculated cavity configuration.
Coupling of higher order transverse magnetic modes TM310 in microwave coaxial cavity of klystron with TE10 mode of rectangular waveguide is analyzed based on power-voltage and LC equivalent-circuit methods respectively. Gap impedances of output cavity were calculated by using of electromagnetic fields which was point-by-point took out from PAC3D of software ISFEL3D. Results obtained in the two methods made an agreement. It is found that larger gap impedance can be obtained by employing calculated cavity configuration.
2007, 29(10): 2521-2524.
doi: 10.3724/SP.J.1146.2006.00296
Abstract:
Numerical simulation of mode conversion from the coaxial waveguide TE◎01 mode to the circular waveguide TE○02 mode is studied. The mode conversion of directly connecting a coaxial waveguide to a cylindrical guide is analyzed, and the effect of a sector-slotted structure in the cylindrical guide for mode conversion is discussed for improving the conversion coefficient, bandwidth property and mode suppression for competing mode. The numerical simulation results with Ansoft HFSS show that 89.3% of the energy from input TE◎01 mode can be converted to the TE○02 mode, the -3dB bandwidth is about 820MHz, and the amplitude of the main competition mode, the TE○01 mode, is 10dB less than that of the TE○02 operating mode.
Numerical simulation of mode conversion from the coaxial waveguide TE◎01 mode to the circular waveguide TE○02 mode is studied. The mode conversion of directly connecting a coaxial waveguide to a cylindrical guide is analyzed, and the effect of a sector-slotted structure in the cylindrical guide for mode conversion is discussed for improving the conversion coefficient, bandwidth property and mode suppression for competing mode. The numerical simulation results with Ansoft HFSS show that 89.3% of the energy from input TE◎01 mode can be converted to the TE○02 mode, the -3dB bandwidth is about 820MHz, and the amplitude of the main competition mode, the TE○01 mode, is 10dB less than that of the TE○02 operating mode.
2007, 29(10): 2525-2528.
doi: 10.3724/SP.J.1146.2006.00973
Abstract:
A new type of System-On-Chip (SOC) integrated with ISFET/REFET/PRE and their signal detection circuits is developed. Carring out the basic chip with commercial standard CMOS processes, the preparation technique of sensitivity membrane compatible with the SOC and interrelated follow-up processes are explored, the H+ sensitive Polypyrrole (Ppy) membrane is emphatically studied by electrochemical polymerization; It is compared with the SOC which developed by low temperature Ta2O5 preparation technique. The new SOC has the sensitivity of 54mV/pH, response time of 0.1s, linear correlation coefficient of 99.99% within the pH range from 1 to 12.
A new type of System-On-Chip (SOC) integrated with ISFET/REFET/PRE and their signal detection circuits is developed. Carring out the basic chip with commercial standard CMOS processes, the preparation technique of sensitivity membrane compatible with the SOC and interrelated follow-up processes are explored, the H+ sensitive Polypyrrole (Ppy) membrane is emphatically studied by electrochemical polymerization; It is compared with the SOC which developed by low temperature Ta2O5 preparation technique. The new SOC has the sensitivity of 54mV/pH, response time of 0.1s, linear correlation coefficient of 99.99% within the pH range from 1 to 12.
2007, 29(10): 2533-2536.
doi: 10.3724/SP.J.1146.2006.00358
Abstract:
This paper presents the speckle suppression technology which includes the soft threshold, the hard threshold and the Garrote function threshold method. It gives the contrast result of the three method. Analyzed the embedded zero-trees wavelet coding method, it presents a SAR(Synthetic Aperture Radar) image coding technology with the speckle suppression. Finally, it presents a compressed SAR image with the speckle suppression. The results show that the speckle of the SAR image is suppressed during coding the SAR image.
This paper presents the speckle suppression technology which includes the soft threshold, the hard threshold and the Garrote function threshold method. It gives the contrast result of the three method. Analyzed the embedded zero-trees wavelet coding method, it presents a SAR(Synthetic Aperture Radar) image coding technology with the speckle suppression. Finally, it presents a compressed SAR image with the speckle suppression. The results show that the speckle of the SAR image is suppressed during coding the SAR image.
2007, 29(10): 2537-2540.
doi: 10.3724/SP.J.1146.2006.00483
Abstract:
The efficiency problem on pre-regulation stage of EPC used in spaceborne TWTA is studied in details. Some advice on how to improve the efficiency is given and the simulation results of Zero-Voltage-Switching circuit (ZVS) are presented. The simulation results show that ZVS has a great effect on the improvement of the circuit efficiency.
The efficiency problem on pre-regulation stage of EPC used in spaceborne TWTA is studied in details. Some advice on how to improve the efficiency is given and the simulation results of Zero-Voltage-Switching circuit (ZVS) are presented. The simulation results show that ZVS has a great effect on the improvement of the circuit efficiency.
2007, 29(10): 2529-2532.
doi: 10.3724/SP.J.1146.2006.00414
Abstract:
The proxy signature with proxy signer privacy protection without a trusted third party put forward by Gu-Zhang-yang(2005), does not posses the strong unforgeability property because of not being able to avoid the suspending-factor. With this scheme, the original signer can forge a valid proxy signature and pass the procedure of verification and revelation, therefore he or she can successfully prove it is signed by a legal proxy signer. To avoid this shortcoming, an improvement of a proxy signature scheme with proxy signer privacy protection is proposed based on the analysis of the Gu-Zhang-yangs scheme.
The proxy signature with proxy signer privacy protection without a trusted third party put forward by Gu-Zhang-yang(2005), does not posses the strong unforgeability property because of not being able to avoid the suspending-factor. With this scheme, the original signer can forge a valid proxy signature and pass the procedure of verification and revelation, therefore he or she can successfully prove it is signed by a legal proxy signer. To avoid this shortcoming, an improvement of a proxy signature scheme with proxy signer privacy protection is proposed based on the analysis of the Gu-Zhang-yangs scheme.
