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2001 Vol. 23, No. 3
Display Method:
2001, 23(3): 209-214.
Abstract:
In this paper, a heuristic algorithm-least efFect (LE) algorithm is proposed for the dynamic centralized wavelength assignment problem in fixed-routing wavelength division multiplexing (WDM) networks without wavelength conversion. Compared with the previously proposed algorithms, LE algorithm can modei the effect of wavelength assignment on the net-work more accurately. Simulation results show that LE algorithm performs better than those algorithms in the most cases.
In this paper, a heuristic algorithm-least efFect (LE) algorithm is proposed for the dynamic centralized wavelength assignment problem in fixed-routing wavelength division multiplexing (WDM) networks without wavelength conversion. Compared with the previously proposed algorithms, LE algorithm can modei the effect of wavelength assignment on the net-work more accurately. Simulation results show that LE algorithm performs better than those algorithms in the most cases.
2001, 23(3): 215-220.
Abstract:
This paper considers the modei of optimal estimation of image information when some of the image data are lost due to transmission errors. A new technology is proposed for image recovery in transform coding based on the boundary information of adjacent blocks, the algorithm for estimating the optimal solution and the analytical form of the gain of SNR. Experimental results show that when SNR increases 10-20 dB, the visual quality can improve from 1 to 3 or 4. Compare with the other theme, the algorithm proposed in this paper improves the quality of both low and high frequency information and can easily be implemented.
This paper considers the modei of optimal estimation of image information when some of the image data are lost due to transmission errors. A new technology is proposed for image recovery in transform coding based on the boundary information of adjacent blocks, the algorithm for estimating the optimal solution and the analytical form of the gain of SNR. Experimental results show that when SNR increases 10-20 dB, the visual quality can improve from 1 to 3 or 4. Compare with the other theme, the algorithm proposed in this paper improves the quality of both low and high frequency information and can easily be implemented.
2001, 23(3): 221-231.
Abstract:
The deficiency of nowadays Intelligent Network (IN) on the support of the personal communication is analyzed in this paper. The conceptions of the customized service and the personai service are defined in connection with the requirement of the personai communication. With the CORBA, mobile agent and smart card technologies, a prototype of personal communication system based on the distributed IN architecture is proposed and implemented. A three-phase scheme is also given for the IN' s smooth evolution towards the distributed archi- tecture.
The deficiency of nowadays Intelligent Network (IN) on the support of the personal communication is analyzed in this paper. The conceptions of the customized service and the personai service are defined in connection with the requirement of the personai communication. With the CORBA, mobile agent and smart card technologies, a prototype of personal communication system based on the distributed IN architecture is proposed and implemented. A three-phase scheme is also given for the IN' s smooth evolution towards the distributed archi- tecture.
2001, 23(3): 232-240.
Abstract:
User s interference in the frequency-hopping of communication net can be analyzed using the independent hit model or the Marcov modei with four hit states. In this paper, it is proposed that the error probabilities and erasure probabilities can be defined respectively in four hit states to adjust parameter effects of a complicated channel modei. The attention is payed to stabilizing the Marcov process with four hit states in fixed user s numbers, so it is suggested that the independent hit model can be used in engineering as to simplify the computation.
User s interference in the frequency-hopping of communication net can be analyzed using the independent hit model or the Marcov modei with four hit states. In this paper, it is proposed that the error probabilities and erasure probabilities can be defined respectively in four hit states to adjust parameter effects of a complicated channel modei. The attention is payed to stabilizing the Marcov process with four hit states in fixed user s numbers, so it is suggested that the independent hit model can be used in engineering as to simplify the computation.
2001, 23(3): 241-247.
Abstract:
Construction of a BCM code on the Rayleigh-fading channel can be realized by combining component codes, whose minimum product distance and Hamming distance are as large as possible, with set partitioning method proposed by Ungerboeck. However, using this mapping method, the complexity of a BCM code constructed is greatly increased, which makes a degradation of the whole performance. In the paper, a new set partitioning method is proposed. Simulation result shows that BCM codes constructed by this mapping method have a better performance than those constructed by using Ungerboeck set partitioning mapping.
Construction of a BCM code on the Rayleigh-fading channel can be realized by combining component codes, whose minimum product distance and Hamming distance are as large as possible, with set partitioning method proposed by Ungerboeck. However, using this mapping method, the complexity of a BCM code constructed is greatly increased, which makes a degradation of the whole performance. In the paper, a new set partitioning method is proposed. Simulation result shows that BCM codes constructed by this mapping method have a better performance than those constructed by using Ungerboeck set partitioning mapping.
2001, 23(3): 248-254.
Abstract:
Currently, the surrogate data method has become a widely used method in testing nonlinearity of time series. However, for the null hypothesis of linearly autocorrelated Gaussian noise with the mean and variance of the raw data, the exiting FT algorithms of generating surrogate data can not reproduce pure frequencies very well. In this paper, the surrogate data method is studied and an improved FT algorithms is proposed. Using the proposed algorithm, the surrogate data sets have the same mean, variance and Fourier spectrum with the original data. This FT algorithm is compared to the previous and proved feasible by using Guass series and chaos time series of the logistic system.
Currently, the surrogate data method has become a widely used method in testing nonlinearity of time series. However, for the null hypothesis of linearly autocorrelated Gaussian noise with the mean and variance of the raw data, the exiting FT algorithms of generating surrogate data can not reproduce pure frequencies very well. In this paper, the surrogate data method is studied and an improved FT algorithms is proposed. Using the proposed algorithm, the surrogate data sets have the same mean, variance and Fourier spectrum with the original data. This FT algorithm is compared to the previous and proved feasible by using Guass series and chaos time series of the logistic system.
2001, 23(3): 255-260.
Abstract:
The wideband digital receiver systems require DDC with high speed and short tuning time in order to intercept narrowband signal in broad tuning bandwidth. However, these requirements can not be met by the commercial DDC. In this paper an efHcient implementation architecture is presented. It combines the flexibility of DFT tuning with the efficiency of the polyphase filter bank decomposition. By first decimating the data prior to filtering and mixing, this architecture gives a better solution of the mismatch between the lower hardware speed and high data rate. The computer simulations show the feasibility of this processing architecture.
The wideband digital receiver systems require DDC with high speed and short tuning time in order to intercept narrowband signal in broad tuning bandwidth. However, these requirements can not be met by the commercial DDC. In this paper an efHcient implementation architecture is presented. It combines the flexibility of DFT tuning with the efficiency of the polyphase filter bank decomposition. By first decimating the data prior to filtering and mixing, this architecture gives a better solution of the mismatch between the lower hardware speed and high data rate. The computer simulations show the feasibility of this processing architecture.
2001, 23(3): 261-267.
Abstract:
This paper starts with the discussion of the principle of reduced-rank(RR) Space-Time Adaptive Processing(STAP). It is followed by a dedication of the performance upper bound of all eigen-based RR methods provided by Cross Spectral Method(CSM) under the condition of a given processor rank and identical secondary sample size. A performance com-parison between two RR STAP processors with prefixed structure and CSM is performed by the means of simulations. It is shown that the performance of time pre-filtering followed by jointly localized STAP structure (i.e. 3DT-SAP) is very close to the upper bound and thereby it is an effective RR approach.
This paper starts with the discussion of the principle of reduced-rank(RR) Space-Time Adaptive Processing(STAP). It is followed by a dedication of the performance upper bound of all eigen-based RR methods provided by Cross Spectral Method(CSM) under the condition of a given processor rank and identical secondary sample size. A performance com-parison between two RR STAP processors with prefixed structure and CSM is performed by the means of simulations. It is shown that the performance of time pre-filtering followed by jointly localized STAP structure (i.e. 3DT-SAP) is very close to the upper bound and thereby it is an effective RR approach.
2001, 23(3): 268-274.
Abstract:
The features of the linearly modulated frequency stepped radar signal (LMFS) and imaging based on it are analyzed. A feasible scheme of target motion compensation is proposed by using designation of radar transmitting signal; ISAR image is achieved by two methods of ISAR image combination for LMFS. The effectiveness of the scheme of target motion compensation is shown by the theoretical analysis and processing of the practical data, and the effectiveness of these methods of ISAR image combination are shown by the theoretical analysis and computer simulation.
The features of the linearly modulated frequency stepped radar signal (LMFS) and imaging based on it are analyzed. A feasible scheme of target motion compensation is proposed by using designation of radar transmitting signal; ISAR image is achieved by two methods of ISAR image combination for LMFS. The effectiveness of the scheme of target motion compensation is shown by the theoretical analysis and processing of the practical data, and the effectiveness of these methods of ISAR image combination are shown by the theoretical analysis and computer simulation.
2001, 23(3): 275-279.
Abstract:
The monopulse estimation for planar array has the property of angle coupling in element and azimuth. 2-dimension monopulse information should be used together to estimate target angle. A linearly constrained adaptive monopulse estimation algorithm for planar array is proposed in this paper, which simplifies the 2-D combined angle estimation algorithm to 1-D angle estimation algorithm. The efficiency of this algorithm is confirmed by computer simulation.
The monopulse estimation for planar array has the property of angle coupling in element and azimuth. 2-dimension monopulse information should be used together to estimate target angle. A linearly constrained adaptive monopulse estimation algorithm for planar array is proposed in this paper, which simplifies the 2-D combined angle estimation algorithm to 1-D angle estimation algorithm. The efficiency of this algorithm is confirmed by computer simulation.
2001, 23(3): 280-285.
Abstract:
A kind of neural networks learning algorithms for multiple-pattern pairs weighted matrix of fuzzy associative memories(FAMs) and its strict theoretic proofs are presented in this paper. Multiple fuzzy pattern pairs can be encoded to store in FAM connection weight matrixes as few as possible by the algorithm, so it can cut down storage space greatly and this algorithm can easily be implimented. Its effectiveness is testified by an example.
A kind of neural networks learning algorithms for multiple-pattern pairs weighted matrix of fuzzy associative memories(FAMs) and its strict theoretic proofs are presented in this paper. Multiple fuzzy pattern pairs can be encoded to store in FAM connection weight matrixes as few as possible by the algorithm, so it can cut down storage space greatly and this algorithm can easily be implimented. Its effectiveness is testified by an example.
2001, 23(3): 286-291.
Abstract:
Based on a linear phased array antenna, sector nulling using phase-only control is analyzed by using a fast algorithm and a partly controlling method. And it can be modeled to a constrained discrete nonlinear optimization problem. An experiment is performed to verify the algorithm and the method.
Based on a linear phased array antenna, sector nulling using phase-only control is analyzed by using a fast algorithm and a partly controlling method. And it can be modeled to a constrained discrete nonlinear optimization problem. An experiment is performed to verify the algorithm and the method.
2001, 23(3): 292-299.
Abstract:
A 360?broad-band analog phase shifter is designed by means of CAD. Linear phase-shift, balancing insertion loss and expanding bandwidth of phase shifter are analyzed in detail. The objective function about phase shifter s bandwidth is also deduced. The analog phase shifter which uses hyperabrupt varactor chips is fabricated with MIC technology. In the frequency range of 1.3-2.1GHz, continuous variable phase-shifter up to 360 and linear deviation of less than 2.5% can be obtained. Its insertion loss varies less than 3dB. Comparing with reported phase shifters, its performances are excellent.
A 360?broad-band analog phase shifter is designed by means of CAD. Linear phase-shift, balancing insertion loss and expanding bandwidth of phase shifter are analyzed in detail. The objective function about phase shifter s bandwidth is also deduced. The analog phase shifter which uses hyperabrupt varactor chips is fabricated with MIC technology. In the frequency range of 1.3-2.1GHz, continuous variable phase-shifter up to 360 and linear deviation of less than 2.5% can be obtained. Its insertion loss varies less than 3dB. Comparing with reported phase shifters, its performances are excellent.
2001, 23(3): 300-303.
Abstract:
In the paper, a characteristic function is introduced and used to characterize quan-titatively global exponential stability of nonlinear continuous neural network . Some sufficient conditions for the network to be exponentially stable under all monotone norms are presented, and the sufficient and necessary condition for lower-triangle neural network to be globally ex-ponentially stable is obtained also.
In the paper, a characteristic function is introduced and used to characterize quan-titatively global exponential stability of nonlinear continuous neural network . Some sufficient conditions for the network to be exponentially stable under all monotone norms are presented, and the sufficient and necessary condition for lower-triangle neural network to be globally ex-ponentially stable is obtained also.
2001, 23(3): 304-307.
Abstract:
In this paper, a new neural network s training method combining back error prop-agation with simulated annealing used to microwave circuit design is discussed. This method can solve the local minimum question of the BP neural network. The new training technique does not require any structure change in neural network model. An example is calculated and. the results verified the proposed technique.
In this paper, a new neural network s training method combining back error prop-agation with simulated annealing used to microwave circuit design is discussed. This method can solve the local minimum question of the BP neural network. The new training technique does not require any structure change in neural network model. An example is calculated and. the results verified the proposed technique.
2001, 23(3): 308-312.
Abstract:
Range migration correction (RMC) is an important procedure in high resolution synthetic aperture radar signal processing. Range-Doppler method carries out RMC by interpolation in range-Doppler domain. This paper first analyzes the range migration problem, makes research on three common used interpolation algorithms: nearest neighbor approxima-tion, Lagrange polynornial interpolation and sinc function interpolation. The general formulas of three algorithms are presented. Their calculating volume is compared. Finally, the computer imaging simulations of point target are used to analyze the algorithms effect on resulted image.
Range migration correction (RMC) is an important procedure in high resolution synthetic aperture radar signal processing. Range-Doppler method carries out RMC by interpolation in range-Doppler domain. This paper first analyzes the range migration problem, makes research on three common used interpolation algorithms: nearest neighbor approxima-tion, Lagrange polynornial interpolation and sinc function interpolation. The general formulas of three algorithms are presented. Their calculating volume is compared. Finally, the computer imaging simulations of point target are used to analyze the algorithms effect on resulted image.
