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1999 Vol. 21, No. 5
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1999, 21(5): 577-584.
Abstract:
In this paper, conjugate cyclic ESPRIT with minimum-redundancy linear-arrays is presented. Theoretical analysis and computer simulation show that the algorithm has better performance, such as extending aperture, being insensitive to noise, having higher resolution, and estimating more sources with fewer sensors. Computer simulation results and comparisons with conjugate cyclic ESPRIT are presented to demonstrate the performance of the proposed algorithm.
In this paper, conjugate cyclic ESPRIT with minimum-redundancy linear-arrays is presented. Theoretical analysis and computer simulation show that the algorithm has better performance, such as extending aperture, being insensitive to noise, having higher resolution, and estimating more sources with fewer sensors. Computer simulation results and comparisons with conjugate cyclic ESPRIT are presented to demonstrate the performance of the proposed algorithm.
1999, 21(5): 585-591.
Abstract:
This paper constructs a family of compactly supported interpolating wavelets with compactly supported duals. Comparing with the existed interpolating wavelets, the new wavelets are greater flexible in design and the decomposition and synthesis algorithms can be realized completely by using FIR filter banks. Finally, the test results show that they perform well in denoising.
This paper constructs a family of compactly supported interpolating wavelets with compactly supported duals. Comparing with the existed interpolating wavelets, the new wavelets are greater flexible in design and the decomposition and synthesis algorithms can be realized completely by using FIR filter banks. Finally, the test results show that they perform well in denoising.
1999, 21(5): 592-599.
Abstract:
This paper considers the single record estimators for cumulants of sinusoids in additive noise. The strong convergence of sample autocorrelation is proved, and the convergence rate is obtained. Conditions for the fourth-order ergodicity are given. Under these conditions, the strong convergence of sample estimates of the fourth-order moment and cumulant is established, and the convergence rate is obtained. Finally, a numerical example is given to verify the results.
This paper considers the single record estimators for cumulants of sinusoids in additive noise. The strong convergence of sample autocorrelation is proved, and the convergence rate is obtained. Conditions for the fourth-order ergodicity are given. Under these conditions, the strong convergence of sample estimates of the fourth-order moment and cumulant is established, and the convergence rate is obtained. Finally, a numerical example is given to verify the results.
1999, 21(5): 600-605.
Abstract:
A new DOA estimator based on beam output is presented in this paper. It uses subarray to form beam and regards these subarrays as equivalent sensors. So a new array is generated. Employing original high-resolution DOA estimators, such as MUSIC, on the new array, DOAs are then obtained. Monte Carlo test and underwater high-resolution array processing experiment are made on linear equipspaced array (LEA) to check the performance of the new method. It is shown from the result of tests that the new method possesses some advantages over the original one. First, it improves the estimation precision and resolution of original method; Second, it reduces the burden of computation; Third, the most important one, it becomes not sensitive to various array errors, such as sensors position/phase error, inconsistency of sensors directionality, etc.. So it is promising on engineering application. Statistical performance analysis and underwater experimental results are given in the paper to verify the conclusion.
A new DOA estimator based on beam output is presented in this paper. It uses subarray to form beam and regards these subarrays as equivalent sensors. So a new array is generated. Employing original high-resolution DOA estimators, such as MUSIC, on the new array, DOAs are then obtained. Monte Carlo test and underwater high-resolution array processing experiment are made on linear equipspaced array (LEA) to check the performance of the new method. It is shown from the result of tests that the new method possesses some advantages over the original one. First, it improves the estimation precision and resolution of original method; Second, it reduces the burden of computation; Third, the most important one, it becomes not sensitive to various array errors, such as sensors position/phase error, inconsistency of sensors directionality, etc.. So it is promising on engineering application. Statistical performance analysis and underwater experimental results are given in the paper to verify the conclusion.
1999, 21(5): 606-612.
Abstract:
This paper constructs a family of M-band orthogonal compactly supported interpolating scaling function, gives a 3-band scaling function and shows that it is not only compactly supported, but also orthogonal and continuous. G.Walter s wavelet sampling theorem(1992) corresponding to the scaling function has the compactly supported interplant. Therefore, the signals in multiresolution subspaces can be reconstructed exactly and quickly without any truncated errors except finite field length errors.
This paper constructs a family of M-band orthogonal compactly supported interpolating scaling function, gives a 3-band scaling function and shows that it is not only compactly supported, but also orthogonal and continuous. G.Walter s wavelet sampling theorem(1992) corresponding to the scaling function has the compactly supported interplant. Therefore, the signals in multiresolution subspaces can be reconstructed exactly and quickly without any truncated errors except finite field length errors.
1999, 21(5): 613-618.
Abstract:
In this paper, an error calibration method of quadrature detector based on SVD technique is presented. The method has been applied to target imaging of high resolution step-frequency MMV radar. The simulation results show good performance of the proposed method.
In this paper, an error calibration method of quadrature detector based on SVD technique is presented. The method has been applied to target imaging of high resolution step-frequency MMV radar. The simulation results show good performance of the proposed method.
1999, 21(5): 619-623.
Abstract:
A new method to resolve fractal inverse problem based on neural network was presented in this paper which can be employed to model a time sequences.The precondition to assure the model was also provided. A piece of echo from a lake was taken to test the algorithm. The result is satisfying.
A new method to resolve fractal inverse problem based on neural network was presented in this paper which can be employed to model a time sequences.The precondition to assure the model was also provided. A piece of echo from a lake was taken to test the algorithm. The result is satisfying.
1999, 21(5): 624-627.
Abstract:
The estimates of attractive domain and convergent rate of nonlinear continuous memory neural network are obtained, and some sufficient conditions for the network to be globally exponentially stable are developed, these results generalize ones in references.
The estimates of attractive domain and convergent rate of nonlinear continuous memory neural network are obtained, and some sufficient conditions for the network to be globally exponentially stable are developed, these results generalize ones in references.
1999, 21(5): 628-633.
Abstract:
Real clutter data collected from land radar are fractally processed. Fractal-based methods for signal detection are presented, and the detector performances are given experimentally. Multifractal is also used to extract multilevel fractal features and further to signal detection. All the methods have better detecting performance.
Real clutter data collected from land radar are fractally processed. Fractal-based methods for signal detection are presented, and the detector performances are given experimentally. Multifractal is also used to extract multilevel fractal features and further to signal detection. All the methods have better detecting performance.
1999, 21(5): 634-639.
Abstract:
This paper presents a new method to evaluate edge detectors objectively and quantitatively. This method is capable of showing correctly the performance of detecting the contour of images, as well as of detecting the fine details of images. The effects of noises on edge detectors can be accurately reported by partitioning the whole test image into three areas having different characteristics and then, at different areas, using different parameters to match the different performance of edge detectors. At the same time, the whole performance of edge detectors is divided into two parts: the edge-extracting ability and the noise-attenuating ability. So, the edge detectors, having different characteristics, can be evaluated comprehensively, accurately and objectively, and be applied to different cases.
This paper presents a new method to evaluate edge detectors objectively and quantitatively. This method is capable of showing correctly the performance of detecting the contour of images, as well as of detecting the fine details of images. The effects of noises on edge detectors can be accurately reported by partitioning the whole test image into three areas having different characteristics and then, at different areas, using different parameters to match the different performance of edge detectors. At the same time, the whole performance of edge detectors is divided into two parts: the edge-extracting ability and the noise-attenuating ability. So, the edge detectors, having different characteristics, can be evaluated comprehensively, accurately and objectively, and be applied to different cases.
1999, 21(5): 640-645.
Abstract:
A high order all digital phase locked loop with tandem structure is presented. A 2-order all digital PLL is implemented and its performance is verified by simulation. An example is given for SDH 2048Kb/s tributary recovery. Its performances are simulated and compared with the theoretical analysis.
A high order all digital phase locked loop with tandem structure is presented. A 2-order all digital PLL is implemented and its performance is verified by simulation. An example is given for SDH 2048Kb/s tributary recovery. Its performances are simulated and compared with the theoretical analysis.
1999, 21(5): 646-651.
Abstract:
The problem of finite precision degrades the cyptologic and statistical properties of chaotic maps, and sequences generated from maps conjugated with Tent map can be reconstructed precisely by short-sequence-prediction. This paper discusses topological conjugation of chaotic maps and its properties, derives the conjugate relation between Tent, logistic and 2nd-order Chebyshev maps. A method is given to produce chaotic sequences which can sustain this predictive attack.
The problem of finite precision degrades the cyptologic and statistical properties of chaotic maps, and sequences generated from maps conjugated with Tent map can be reconstructed precisely by short-sequence-prediction. This paper discusses topological conjugation of chaotic maps and its properties, derives the conjugate relation between Tent, logistic and 2nd-order Chebyshev maps. A method is given to produce chaotic sequences which can sustain this predictive attack.
1999, 21(5): 652-659.
Abstract:
All the ABR congestion control algorithms reported are designed to achieve max-min fairness. In this paper, a new algorithm named dynamic bandwidth allocation algorithm is presented. Under the same framework, the algorithm can achieve fairness under several given criterion. Simulation result shows that the new algorithm works well under various network configurations, various traffic classes, and scale well to LAN or WAN either.
All the ABR congestion control algorithms reported are designed to achieve max-min fairness. In this paper, a new algorithm named dynamic bandwidth allocation algorithm is presented. Under the same framework, the algorithm can achieve fairness under several given criterion. Simulation result shows that the new algorithm works well under various network configurations, various traffic classes, and scale well to LAN or WAN either.
1999, 21(5): 660-664.
Abstract:
A new method for construction of authentication codes with arbitration and secret authentication codes with arbitration is presented, some results are given.
A new method for construction of authentication codes with arbitration and secret authentication codes with arbitration is presented, some results are given.
1999, 21(5): 665-670.
Abstract:
In this paper, we present three different kinds of motion compensation methods for stepped frequency radar, which are time domain compensation method, frequency domain compensation method and mini entropy compensation method. Then, an improved method by combining the time domain method and frequency domain method is provided. Finally, the motion compensation requested from stepped frequency radar is also mentioned.
In this paper, we present three different kinds of motion compensation methods for stepped frequency radar, which are time domain compensation method, frequency domain compensation method and mini entropy compensation method. Then, an improved method by combining the time domain method and frequency domain method is provided. Finally, the motion compensation requested from stepped frequency radar is also mentioned.
1999, 21(5): 671-678.
Abstract:
In order to overcome the conflicts between high range resolution and wide bandwidth of Linear Frequency Modulated (LFM) signal, a new operating mode of radar is suggested. The radar signal is a series of LFM signal-LFM burst. When the echoes return, every burst was compressed with matched filter first. Integration was accomplished later among these bursts to improve the range resolution. LFM burst mode can raise the radar range resolution several times without widening the system bandwidth. On the other han...
In order to overcome the conflicts between high range resolution and wide bandwidth of Linear Frequency Modulated (LFM) signal, a new operating mode of radar is suggested. The radar signal is a series of LFM signal-LFM burst. When the echoes return, every burst was compressed with matched filter first. Integration was accomplished later among these bursts to improve the range resolution. LFM burst mode can raise the radar range resolution several times without widening the system bandwidth. On the other han...
1999, 21(5): 679-685.
Abstract:
The scatter spectrum of radio waves by a dusty plasma has been studed with the dynamic factor which was derived from the kinetic theory. It is found that for the case of cooled electrons kD1 (D is the Debye length, and k=|k|=|ks-k0|, k0 and ks is the incident and scatter wave vector, respectivly) the dusty paticles play an important role in the scattering due to its huge charge number. There is a characteristic spiky fine structure in the scatter spectrum, which is of the dust-acoustic wave frequency shift.
The scatter spectrum of radio waves by a dusty plasma has been studed with the dynamic factor which was derived from the kinetic theory. It is found that for the case of cooled electrons kD1 (D is the Debye length, and k=|k|=|ks-k0|, k0 and ks is the incident and scatter wave vector, respectivly) the dusty paticles play an important role in the scattering due to its huge charge number. There is a characteristic spiky fine structure in the scatter spectrum, which is of the dust-acoustic wave frequency shift.
1999, 21(5): 686-691.
Abstract:
The photocurrent-voltage characteristics and photoelectric sensitivity of a-Si:H samples with slit and comb electrodes are measured. A method for calculating the charge intensifying gain from the photoelectric sensitivity is proposed. The obtained charge intensifying gain of a-Si:H under an electric field of 105 V/cm with this method is as high as 4.3103. The generation process of the charge intensification effect in a-Si:H is discussed on the basis of the energy level diagram. And the product of electron ...
The photocurrent-voltage characteristics and photoelectric sensitivity of a-Si:H samples with slit and comb electrodes are measured. A method for calculating the charge intensifying gain from the photoelectric sensitivity is proposed. The obtained charge intensifying gain of a-Si:H under an electric field of 105 V/cm with this method is as high as 4.3103. The generation process of the charge intensification effect in a-Si:H is discussed on the basis of the energy level diagram. And the product of electron ...
1999, 21(5): 692-697.
Abstract:
The single-walled carbon nanotubes(SWCNTs) are synthesized and purified.A water colloid of SWCNTs is prepared and used to assemble SWCNTs on a gold film surface.Its STM image shows sorter SWCNTs standing-on gold film surface.The crystal grain image of gold thin film and an atomic structure highly oriented pyrolytic graphite (HOPG) are observed using a scanning tunneling microscope(STE) with the SWCNT tip made from the water colloid mentioned above.The SWCNTs standing-on gold film surface is very important for measuring electronic properteis of carbon anotubes,fabricating field emission cathode,structing nanoelectrnic devices,and makign tips of a scannign probe microscope(SPM).
The single-walled carbon nanotubes(SWCNTs) are synthesized and purified.A water colloid of SWCNTs is prepared and used to assemble SWCNTs on a gold film surface.Its STM image shows sorter SWCNTs standing-on gold film surface.The crystal grain image of gold thin film and an atomic structure highly oriented pyrolytic graphite (HOPG) are observed using a scanning tunneling microscope(STE) with the SWCNT tip made from the water colloid mentioned above.The SWCNTs standing-on gold film surface is very important for measuring electronic properteis of carbon anotubes,fabricating field emission cathode,structing nanoelectrnic devices,and makign tips of a scannign probe microscope(SPM).
1999, 21(5): 698-701.
Abstract:
This paper presnets a globall optimal composite filtering solution for a two-level hybrid multisensor system.It is shown that the fusion center first neeeds to fuse the local estimates from the L sensors,and then to update recursively the fused track by using a Kalman filter based on the observations of the other N-L sensors.Thsi paper also considers the estimation problems based on the different Cartesian coordinates.
This paper presnets a globall optimal composite filtering solution for a two-level hybrid multisensor system.It is shown that the fusion center first neeeds to fuse the local estimates from the L sensors,and then to update recursively the fused track by using a Kalman filter based on the observations of the other N-L sensors.Thsi paper also considers the estimation problems based on the different Cartesian coordinates.
1999, 21(5): 702-705.
Abstract:
A new algorithm, concerned with the anti-collision used in recognition of transponders in RFID (Radio Frequency Identification) system is built and its stability condition is pointed out as well. The mathematical model works very well in computer simulation and has taken an important part in the design of RFID system.
A new algorithm, concerned with the anti-collision used in recognition of transponders in RFID (Radio Frequency Identification) system is built and its stability condition is pointed out as well. The mathematical model works very well in computer simulation and has taken an important part in the design of RFID system.
1999, 21(5): 706-709.
Abstract:
This paper reviews different properties of non-stationary signals and white noise after wavelet decomposition, and presents a new method of white noise reduction based on wavelet transform which can be realized with fast algorithm. The simulation results show that the method can be applied to white noise reduction of non-stationary signals efficiently.
This paper reviews different properties of non-stationary signals and white noise after wavelet decomposition, and presents a new method of white noise reduction based on wavelet transform which can be realized with fast algorithm. The simulation results show that the method can be applied to white noise reduction of non-stationary signals efficiently.
1999, 21(5): 710-712.
Abstract:
In this paper the superior partial properties in time and frequency fiels of wavelet transform are used to classify these two kinds signals.The results are that only requiring three parameters,this algorithm can reach high recogniton probability.This method may introduce electro-magnetism detection to the field of nuclear monitor in the future.
In this paper the superior partial properties in time and frequency fiels of wavelet transform are used to classify these two kinds signals.The results are that only requiring three parameters,this algorithm can reach high recogniton probability.This method may introduce electro-magnetism detection to the field of nuclear monitor in the future.
1999, 21(5): 713-717.
Abstract:
Gabor representations are signal expansion using sets of functions that are localized and concentrated in time and frequency domain. This characteristic makes them be suitable for processing time-dependent or nonstationary signal. It is shown that Gabor representations formulated with frame theory can be used to remove noise from seismic data. The simulation shows that Gabor representations filtering techniques can outperform SVD eigenimage filtering techniques in the removal of noise.
Gabor representations are signal expansion using sets of functions that are localized and concentrated in time and frequency domain. This characteristic makes them be suitable for processing time-dependent or nonstationary signal. It is shown that Gabor representations formulated with frame theory can be used to remove noise from seismic data. The simulation shows that Gabor representations filtering techniques can outperform SVD eigenimage filtering techniques in the removal of noise.
1999, 21(5): 718-720.
Abstract:
A key escrow cryptosystem can not only provide protection for user s privacy, while at the same time, allows for the wiretapping when lawfully authorized. In this paper, a secret key escrow system based on Asmuth-Bloom threshold scheme is given and its security is analysed.
A key escrow cryptosystem can not only provide protection for user s privacy, while at the same time, allows for the wiretapping when lawfully authorized. In this paper, a secret key escrow system based on Asmuth-Bloom threshold scheme is given and its security is analysed.
