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2002 Vol. 24, No. 10
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2002, 24(10): 1297-1303.
Abstract:
Independent component analysis aims to find a linearly transformation to coordinates in which the data are maximally statistical independent. In the method, by using the independent vector basis, the mixed signal will be decomposed to the independent components. Under some conditions, it is equivalent to the blind source separation. In this paper, the independent vector basis can be got by using the nonlinear minimizing mean square criterion. It can estimate the DOA of ULA by using the character of the independent vector basis.
Independent component analysis aims to find a linearly transformation to coordinates in which the data are maximally statistical independent. In the method, by using the independent vector basis, the mixed signal will be decomposed to the independent components. Under some conditions, it is equivalent to the blind source separation. In this paper, the independent vector basis can be got by using the nonlinear minimizing mean square criterion. It can estimate the DOA of ULA by using the character of the independent vector basis.
2002, 24(10): 1304-1309.
Abstract:
In this paper, researches are deep done on using PCNN-pulse coupled neural network, a new artificial neural network based on biology, to reduce binary images noise and smooth images. Meanwhile, the image restoration algorithm based on PCNN is brought forward. The results of computer simulations show that noisy binary images can be restored efficiently by using PCNN and the increasing SNRs of restored images by using PCNN are higher than those by using one of two usual image restoration methods, the median filter and the mean filter.
In this paper, researches are deep done on using PCNN-pulse coupled neural network, a new artificial neural network based on biology, to reduce binary images noise and smooth images. Meanwhile, the image restoration algorithm based on PCNN is brought forward. The results of computer simulations show that noisy binary images can be restored efficiently by using PCNN and the increasing SNRs of restored images by using PCNN are higher than those by using one of two usual image restoration methods, the median filter and the mean filter.
2002, 24(10): 1310-1315.
Abstract:
This paper presents a new strategy for efficiently coding stereo video sequences. In the scheme, the auxiliary sequence is coded by disparity compensated prediction and 3D-SPIHT algorithm. 3D-SPIHT algorithm is based on genuine 3D wavelet transform, and implements a three dimensional extension of SPIHT in still image coding by defining a new spatio-temporal orientation tree structure. The scheme can provide comparable performance to the conventional method with minimal computational complexity and produce an embedded bit stream in the auxiliary sequence. According to channel bandwidth, the bit rate can be adaptively adjusted so that the best quality of the auxiliary sequence is obtained.
This paper presents a new strategy for efficiently coding stereo video sequences. In the scheme, the auxiliary sequence is coded by disparity compensated prediction and 3D-SPIHT algorithm. 3D-SPIHT algorithm is based on genuine 3D wavelet transform, and implements a three dimensional extension of SPIHT in still image coding by defining a new spatio-temporal orientation tree structure. The scheme can provide comparable performance to the conventional method with minimal computational complexity and produce an embedded bit stream in the auxiliary sequence. According to channel bandwidth, the bit rate can be adaptively adjusted so that the best quality of the auxiliary sequence is obtained.
2002, 24(10): 1316-1320.
Abstract:
A fast codebook training algorithm without the computation of distortion by the property of centroid sequence convergence is presented in this paper. The performance of the new algorithm is tested by typical test image Lena. The result shows that the PSNR difference between the new algorithm and LBG is O.ldB, but the running time of it is at most one half of LBG.
A fast codebook training algorithm without the computation of distortion by the property of centroid sequence convergence is presented in this paper. The performance of the new algorithm is tested by typical test image Lena. The result shows that the PSNR difference between the new algorithm and LBG is O.ldB, but the running time of it is at most one half of LBG.
2002, 24(10): 1321-1328.
Abstract:
As an effective method to provide copyright protection for digital media, digital watermarking has drawn extensive attention recently. By inserting the signature watermarking DCT coefficients into some middle-high frequency range DCT coefficients of the original image, the paper proposes a watermarking scheme of embedding an invisible signature in a digital image based on the combination of wavelet transform and cosine transform. The experimental results demonstrate the robustness and invisibility of digital image watermarking, and the signature watermark can be reliably and explicitly detected even though the watermarked image being degraded by commonly used image processing techniques.
As an effective method to provide copyright protection for digital media, digital watermarking has drawn extensive attention recently. By inserting the signature watermarking DCT coefficients into some middle-high frequency range DCT coefficients of the original image, the paper proposes a watermarking scheme of embedding an invisible signature in a digital image based on the combination of wavelet transform and cosine transform. The experimental results demonstrate the robustness and invisibility of digital image watermarking, and the signature watermark can be reliably and explicitly detected even though the watermarked image being degraded by commonly used image processing techniques.
2002, 24(10): 1329-1333.
Abstract:
The subimaging target recognition system of infrared rosette scanning is the main optimal terminal guidance system, however, the resolution of the imaging space is not high. Based on the optimal controlling rule of scanning parameter, this paper proposes the phaseshift parameter controlling method which is performed through shifting the phase and overlaping the multi-frame phase diagrams. Thus, high resolution of imaging space under the condition of high speed, nice efficiency is achieved. The experimental results of DSP system show that this technology improves the image resolution of the system effectively.
The subimaging target recognition system of infrared rosette scanning is the main optimal terminal guidance system, however, the resolution of the imaging space is not high. Based on the optimal controlling rule of scanning parameter, this paper proposes the phaseshift parameter controlling method which is performed through shifting the phase and overlaping the multi-frame phase diagrams. Thus, high resolution of imaging space under the condition of high speed, nice efficiency is achieved. The experimental results of DSP system show that this technology improves the image resolution of the system effectively.
2002, 24(10): 1334-1340.
Abstract:
As the rank of Volterra adaptive filter interferes with predictive performance, how to determine the optimal rank of Volterra adaptive filter becomes a key problem in practical prediction. Using theory of phase space reconstruction, this paper derives that the optimal rank of Volterra adaptive filter equals the lowest embedding dimension of chaotic dynamical systems. It is shown through some chaotic series experiments that this method is successful in Volterra adaptive predication and robust to the noise of different levels added to the chaotic time series.
As the rank of Volterra adaptive filter interferes with predictive performance, how to determine the optimal rank of Volterra adaptive filter becomes a key problem in practical prediction. Using theory of phase space reconstruction, this paper derives that the optimal rank of Volterra adaptive filter equals the lowest embedding dimension of chaotic dynamical systems. It is shown through some chaotic series experiments that this method is successful in Volterra adaptive predication and robust to the noise of different levels added to the chaotic time series.
2002, 24(10): 1341-1345.
Abstract:
In this paper, stability losing of periodic solution and chaotic phenomenon in a simplest neuron equation with time delay are studied, The numerical simulations show that a new chaotic source is found in a first order nonlinear dynamical system. Some waveform diagrams, phase portraits, power spectra and plots of largest Lyapunov exponent are also given.
In this paper, stability losing of periodic solution and chaotic phenomenon in a simplest neuron equation with time delay are studied, The numerical simulations show that a new chaotic source is found in a first order nonlinear dynamical system. Some waveform diagrams, phase portraits, power spectra and plots of largest Lyapunov exponent are also given.
2002, 24(10): 1346-1351.
Abstract:
It is very difficult to resolve multiple jammers in the mainlobe of a passive monopulse radar. This paper discusses monopulse radar response to noise frequency modulation (FM) jamming. By means of selecting proper receiver bandwidth, it makes jamming pulses (receiver output) separate. Then instantaneous angles of jammers are measured. These angles can be resolved by a statistic method. The method is verified with the results of computer simulation.
It is very difficult to resolve multiple jammers in the mainlobe of a passive monopulse radar. This paper discusses monopulse radar response to noise frequency modulation (FM) jamming. By means of selecting proper receiver bandwidth, it makes jamming pulses (receiver output) separate. Then instantaneous angles of jammers are measured. These angles can be resolved by a statistic method. The method is verified with the results of computer simulation.
2002, 24(10): 1352-1357.
Abstract:
The imaging method on low-altitude target in strong ground clutter is presented. The identical amount of stretching time-delay with the adjoined echoes is applied in the signal stretching process, and then the ground clutter is filtered through the one-order canceller. Furthermore the targets motion parameters can be accurately estimated by the narrow pulse signals on the constant carrier, so the motion compensation can be achieved. After the theoretical analysis, the validity is proven by simulation results finally.
The imaging method on low-altitude target in strong ground clutter is presented. The identical amount of stretching time-delay with the adjoined echoes is applied in the signal stretching process, and then the ground clutter is filtered through the one-order canceller. Furthermore the targets motion parameters can be accurately estimated by the narrow pulse signals on the constant carrier, so the motion compensation can be achieved. After the theoretical analysis, the validity is proven by simulation results finally.
2002, 24(10): 1358-1365.
Abstract:
In this pa per, the characteristics of communication electronic warfare and communication interception information (CI2) are analyzed concisely. IFS/CI2: an intelligent fusion system of CI2 is introduced. The fusion model and key methods are discussed especially. Some problems left to be solved in the future are pointed out finally.
In this pa per, the characteristics of communication electronic warfare and communication interception information (CI2) are analyzed concisely. IFS/CI2: an intelligent fusion system of CI2 is introduced. The fusion model and key methods are discussed especially. Some problems left to be solved in the future are pointed out finally.
2002, 24(10): 1366-1371.
Abstract:
This paper presents a new method of designing an interleaver for turbo codes, which is termed as Golden-spread interleaver. This method fits for designing interleavers of arbitrary length. The principle and process are detailed with the analysis of an interleaver design for 16 states turbo codes. The simulation results are also presented.
This paper presents a new method of designing an interleaver for turbo codes, which is termed as Golden-spread interleaver. This method fits for designing interleavers of arbitrary length. The principle and process are detailed with the analysis of an interleaver design for 16 states turbo codes. The simulation results are also presented.
2002, 24(10): 1372-1377.
Abstract:
Code Division Multiple Access (CDMA) is an effective technique to support radio multimedia service. This paper presents an analysis on the uplink capacity of a multimedia CDMA system under multicell environment. The effect of the users maximum transmission power constraints on the system capacity is analyzed with and without considering the users active factors. The derivations and computation results show that the users maximum transmission power constraints decrease the system capacity.
Code Division Multiple Access (CDMA) is an effective technique to support radio multimedia service. This paper presents an analysis on the uplink capacity of a multimedia CDMA system under multicell environment. The effect of the users maximum transmission power constraints on the system capacity is analyzed with and without considering the users active factors. The derivations and computation results show that the users maximum transmission power constraints decrease the system capacity.
2002, 24(10): 1378-1384.
Abstract:
In this paper, the co-channel interference on the downlink channel of the MC-CDMA cellular system is investigated. The analytic formula of the co-channel interference is induced. The downlink channel performance of the MC-CDMA cellular system with co-channel interference is obtained by the Monte Carlo simulations. The simulations show that the MC-CDMA cellular system has large capacity under co-channel interference when the frequency reuse factor is 1/7.
In this paper, the co-channel interference on the downlink channel of the MC-CDMA cellular system is investigated. The analytic formula of the co-channel interference is induced. The downlink channel performance of the MC-CDMA cellular system with co-channel interference is obtained by the Monte Carlo simulations. The simulations show that the MC-CDMA cellular system has large capacity under co-channel interference when the frequency reuse factor is 1/7.
2002, 24(10): 1385-1390.
Abstract:
This paper presents a new method of fast code acquisition under low SNR, and large Doppler shift condition. The method gives decision base on the peak existence in the spectral of instant correlation between the local code and the zero-IF received signal. This scheme not only promises a performance as good as that of parallel channel optimum receiver but also has a much simpler structure.
This paper presents a new method of fast code acquisition under low SNR, and large Doppler shift condition. The method gives decision base on the peak existence in the spectral of instant correlation between the local code and the zero-IF received signal. This scheme not only promises a performance as good as that of parallel channel optimum receiver but also has a much simpler structure.
2002, 24(10): 1391-1397.
Abstract:
In this paper, an algorithm based on the packet drop history in RED is presented, aimed at solving the problem that the bandwidth is not balancedly allocated to responsive and unresponsive flows in today s Internet. This algorithm is able to detect high sending-rate flows and to drop the arriving packets from them with a calculated probability, hence to prevent the bandwidth from being occupied excessively by these flows. The effect of this algorithm has been proven in different scenarios by simulations.
In this paper, an algorithm based on the packet drop history in RED is presented, aimed at solving the problem that the bandwidth is not balancedly allocated to responsive and unresponsive flows in today s Internet. This algorithm is able to detect high sending-rate flows and to drop the arriving packets from them with a calculated probability, hence to prevent the bandwidth from being occupied excessively by these flows. The effect of this algorithm has been proven in different scenarios by simulations.
2002, 24(10): 1398-1404.
Abstract:
For enlarging the capacities of WDM star networks free from the number of limited wavelengths, a scheme of reusing wavelengths twice is proposed in this paper. According to the scheme, not only the number of nodes can be increased twice, but also all the data wavelengths can be reused twice in the network and the throughput of the network is increased twice. Under the same number of nodes, not only half of fibers can be saved, but also the delay of network can be greatly lowered and the properties of the network can be efficiently improved.
For enlarging the capacities of WDM star networks free from the number of limited wavelengths, a scheme of reusing wavelengths twice is proposed in this paper. According to the scheme, not only the number of nodes can be increased twice, but also all the data wavelengths can be reused twice in the network and the throughput of the network is increased twice. Under the same number of nodes, not only half of fibers can be saved, but also the delay of network can be greatly lowered and the properties of the network can be efficiently improved.
2002, 24(10): 1405-1411.
Abstract:
A normalized two dimensional band-limited Weierstrass fractal function is used for modeling the rough surface. Based on Kirchhoff theory, an analytic solution of the average electromagnetic scattering field and the variance of scattering intensity are derived with emphasis on examining the relation of fractal dimension with the scattering pattern. The important conclusion is obtained that the diffracted envelope slopes of scattering pattern can be approximated to a slope of linear equation.
A normalized two dimensional band-limited Weierstrass fractal function is used for modeling the rough surface. Based on Kirchhoff theory, an analytic solution of the average electromagnetic scattering field and the variance of scattering intensity are derived with emphasis on examining the relation of fractal dimension with the scattering pattern. The important conclusion is obtained that the diffracted envelope slopes of scattering pattern can be approximated to a slope of linear equation.
2002, 24(10): 1412-1417.
Abstract:
An integralization design method in the antenna and feed system of active phased array for low side lobe is presented in this paper. From some main rsepects detail how to do the integral design. Some experiments have been done on the 248 elements antenna array. The measured peak side lobe level and the zero depth of the difference pattern are all lower than -31dB. When the pattern scan to 60, the peak side lobe level is not higher than -26.5dB. It is shown that the integralization design is necessary.
An integralization design method in the antenna and feed system of active phased array for low side lobe is presented in this paper. From some main rsepects detail how to do the integral design. Some experiments have been done on the 248 elements antenna array. The measured peak side lobe level and the zero depth of the difference pattern are all lower than -31dB. When the pattern scan to 60, the peak side lobe level is not higher than -26.5dB. It is shown that the integralization design is necessary.
2002, 24(10): 1418-1423.
Abstract:
In this paper, a more efficient FDTD algorithm, with the Gilbert s equation of motion being discretized directly, is introduced for the analysis of the RCS of a microstrip patch on an arbitrarily biased ferrite substrate. Some new techniques are adopted. Numerical examples are given.
In this paper, a more efficient FDTD algorithm, with the Gilbert s equation of motion being discretized directly, is introduced for the analysis of the RCS of a microstrip patch on an arbitrarily biased ferrite substrate. Some new techniques are adopted. Numerical examples are given.
2002, 24(10): 1424-1427.
Abstract:
This paper applies a multiple population Genetic Algorithm (GA) to solving the TSP (Traveling Salesman Problem). Different populations apply different mutation factors to achieve different search objects. The transition factor among the groups is used to solve the premature convergence problem under some circumstances. It accelerates search process in state space. The experimental results show that this algorithm has great advantage of convergence property over canonical genetic algorithm.
This paper applies a multiple population Genetic Algorithm (GA) to solving the TSP (Traveling Salesman Problem). Different populations apply different mutation factors to achieve different search objects. The transition factor among the groups is used to solve the premature convergence problem under some circumstances. It accelerates search process in state space. The experimental results show that this algorithm has great advantage of convergence property over canonical genetic algorithm.
2002, 24(10): 1428-1432.
Abstract:
In this paper, chaotic synchronization in a coupled system of neuron model with discrete time delay is studied. A chaotic system of neuron model with discrete time delay is sensitive to the continuous initial function. For arbitrary activate function, a general condition for strong chaotic synchronization are derived by using analytic method.
In this paper, chaotic synchronization in a coupled system of neuron model with discrete time delay is studied. A chaotic system of neuron model with discrete time delay is sensitive to the continuous initial function. For arbitrary activate function, a general condition for strong chaotic synchronization are derived by using analytic method.
2002, 24(10): 1433-1436.
Abstract:
Ray-tracing technique is an efficient method to analyse the propagation in urban and indoor environment, but there are still many questions which need to be studied while realizing. In this paper, octatree technique which was first used in computer graphics is used in ray-tracing, and the ray-tracing efficiency is improved.
Ray-tracing technique is an efficient method to analyse the propagation in urban and indoor environment, but there are still many questions which need to be studied while realizing. In this paper, octatree technique which was first used in computer graphics is used in ray-tracing, and the ray-tracing efficiency is improved.
2002, 24(10): 1437-1440.
Abstract:
In this paper, Coifman intervallic scaling functions are used as basis and testing functions in the moment method solution of electromagnetic field integral equation. The number of numerical integral is reduced with the help of the vanishing moment of Coifman scaling functions. Two methods of vanishing moment approximating are proposed for integral equations with different kernels.
In this paper, Coifman intervallic scaling functions are used as basis and testing functions in the moment method solution of electromagnetic field integral equation. The number of numerical integral is reduced with the help of the vanishing moment of Coifman scaling functions. Two methods of vanishing moment approximating are proposed for integral equations with different kernels.
