ISSN 
2000 Vol. 29, No. 5
2000, 29(5): 457-460.
Abstract:
By using blind signal separation rather than resort to multidimensional search, an algorithm for DOA estimation of coherently distributed signals is given, which is applicable for circumstance where coherently distributed sources with different angular signal density coexist and is not limited to uniform linear array. Numerical results show that performance threshold of distributed parameter is present and performance of DOA estimation is insensitive to distributed parameters of other sources.
By using blind signal separation rather than resort to multidimensional search, an algorithm for DOA estimation of coherently distributed signals is given, which is applicable for circumstance where coherently distributed sources with different angular signal density coexist and is not limited to uniform linear array. Numerical results show that performance threshold of distributed parameter is present and performance of DOA estimation is insensitive to distributed parameters of other sources.
2000, 29(5): 461-464.
Abstract:
By analyzing the problems in the design of ultra-wide band radar receiver, a new method is proposed in this paper, in which, a new kind of channel dropping filter is designed using multiscale method of wavelet theory. The compensation method in the practical design is also discussed.
By analyzing the problems in the design of ultra-wide band radar receiver, a new method is proposed in this paper, in which, a new kind of channel dropping filter is designed using multiscale method of wavelet theory. The compensation method in the practical design is also discussed.
2000, 29(5): 465-468.
Abstract:
A class of chaotic sequences generated by piecewise linear (PWL) mappings and noninvertible transformation is proposed as the spreading codes in An A-CDMA system. The theoretical analysis shows that the chaotic sequences serve as spreading codes for A-CDMA. The effect of the finite precision and the length of spreading gain on the properties are investigated by means of computer experiments. The result shows that the properties of chaotic spreading sequences are superior to those of m-sequence, and the number of obtained sequences is found to be larger than the number of m-sequences of the same length. The feasibility of the chaotic sequences as spreading codes for A-CDMA is verified.
A class of chaotic sequences generated by piecewise linear (PWL) mappings and noninvertible transformation is proposed as the spreading codes in An A-CDMA system. The theoretical analysis shows that the chaotic sequences serve as spreading codes for A-CDMA. The effect of the finite precision and the length of spreading gain on the properties are investigated by means of computer experiments. The result shows that the properties of chaotic spreading sequences are superior to those of m-sequence, and the number of obtained sequences is found to be larger than the number of m-sequences of the same length. The feasibility of the chaotic sequences as spreading codes for A-CDMA is verified.
2000, 29(5): 469-474.
Abstract:
In this paper, the concept and background of information Warfare are introduced. The encryption techniques for protecting information both for offensive and defensive are described. More than twenty block cipher algorihtms are discussed. Especially emphases are given to those algorithms representing the current development of encryption technology in recent years, which might provide some new ideas to the techniques.
In this paper, the concept and background of information Warfare are introduced. The encryption techniques for protecting information both for offensive and defensive are described. More than twenty block cipher algorihtms are discussed. Especially emphases are given to those algorithms representing the current development of encryption technology in recent years, which might provide some new ideas to the techniques.
2000, 29(5): 475-478.
Abstract:
This paper presents a new algorithm that utilizes wavelet for lossless compression. Based on linear prediction and Haar multiresolution representation, the wavelet coefficients are divided into two parts according to their values. Those two parts and the location information of decomposing will be compressed effectively by arithmetic coding respectively. Experimental results show that the new algorithm is very practical especially for lossless compression.
This paper presents a new algorithm that utilizes wavelet for lossless compression. Based on linear prediction and Haar multiresolution representation, the wavelet coefficients are divided into two parts according to their values. Those two parts and the location information of decomposing will be compressed effectively by arithmetic coding respectively. Experimental results show that the new algorithm is very practical especially for lossless compression.
2000, 29(5): 479-482.
Abstract:
In this paper, a structure matrix vector quantization algorithm based on wavelet transform is proposed. After the multiresolution pyramidal decomposition of wavelet transform, the similarity among the wavelet coefficients of subbands is obtained, and transmit the dividing information of the subband m to the subband m-1. After classifying vector quantization,the results are more compressed by structure matrix based on the structure specialty of the subbands Experiments show that the algorithm performs better than others in the aspects of high compression ratio and high image quantization.
In this paper, a structure matrix vector quantization algorithm based on wavelet transform is proposed. After the multiresolution pyramidal decomposition of wavelet transform, the similarity among the wavelet coefficients of subbands is obtained, and transmit the dividing information of the subband m to the subband m-1. After classifying vector quantization,the results are more compressed by structure matrix based on the structure specialty of the subbands Experiments show that the algorithm performs better than others in the aspects of high compression ratio and high image quantization.
2000, 29(5): 483-489.
Abstract:
A real discrete Gabor expansion (RDGE) for finite and infinite sequences is defined in this paper. By using the similar method applied to the complex discrete Gabor expansion (CDGE), a significant computation of the RDGE can be saved when compared to the computation of the widely used CDGE. And the RDGE is more convenient to be implemented by both software and hardware due to its real operations. In addition, the RDGE has a very simple relationship with the CDGE so that the CDGE coefficients can be easily obtained from the RDGE coefficients. As a result a direct replacement of the existing CDGE by the proposed RDGE is possible.
A real discrete Gabor expansion (RDGE) for finite and infinite sequences is defined in this paper. By using the similar method applied to the complex discrete Gabor expansion (CDGE), a significant computation of the RDGE can be saved when compared to the computation of the widely used CDGE. And the RDGE is more convenient to be implemented by both software and hardware due to its real operations. In addition, the RDGE has a very simple relationship with the CDGE so that the CDGE coefficients can be easily obtained from the RDGE coefficients. As a result a direct replacement of the existing CDGE by the proposed RDGE is possible.
2000, 29(5): 490-494.
Abstract:
In this paper, the principle of SAMA(Spread ALOHA Multiple Access) protocol is briefly introduced, and compared with spread spectrum CDMA. A performance analysis is also given.
In this paper, the principle of SAMA(Spread ALOHA Multiple Access) protocol is briefly introduced, and compared with spread spectrum CDMA. A performance analysis is also given.
2000, 29(5): 499-503.
Abstract:
This paper presents a new part-filled sample rectangle waveguide sensor for tasting medium and high loss dielectric material. The electromagnetic field solutions are obtained. The expressions for the relationship between the material's electromagnetic parameters (ε、μ) to and the sensor network's S-parameters are developed. The numerical calculation results are given.
This paper presents a new part-filled sample rectangle waveguide sensor for tasting medium and high loss dielectric material. The electromagnetic field solutions are obtained. The expressions for the relationship between the material's electromagnetic parameters (ε、μ) to and the sensor network's S-parameters are developed. The numerical calculation results are given.
2000, 29(5): 504-507.
Abstract:
This paper presents domain decomposition method which is applied in the analysis of electromagnetic problems. The characteristic impedance of quasi TEM transmission lines are calculated by this method. The convergence property and computational efficiency of DDM are studied. The characteristic impedance of rectangular coaxial line is computed by fast Fourier transforms on divided several regular domain. The numerical results obtained show that DDM reduce both the computational complexity and computing time.
This paper presents domain decomposition method which is applied in the analysis of electromagnetic problems. The characteristic impedance of quasi TEM transmission lines are calculated by this method. The convergence property and computational efficiency of DDM are studied. The characteristic impedance of rectangular coaxial line is computed by fast Fourier transforms on divided several regular domain. The numerical results obtained show that DDM reduce both the computational complexity and computing time.
2000, 29(5): 508-511.
Abstract:
PLZT[Pb1-xLaz(Zr1-yTiy)(1-x)/4O4] polycrystal ceramic powder are synthesed through by drothermal method. The influences of reaction temperature, time and mineralizer concentration on the PLZT crystallization process are discussed. The results showed that the Perovskite structure can be obtained at reaction temperature 200℃, mineralizer concentration 5 mol and reaction time 12 h.
PLZT[Pb1-xLaz(Zr1-yTiy)(1-x)/4O4] polycrystal ceramic powder are synthesed through by drothermal method. The influences of reaction temperature, time and mineralizer concentration on the PLZT crystallization process are discussed. The results showed that the Perovskite structure can be obtained at reaction temperature 200℃, mineralizer concentration 5 mol and reaction time 12 h.
2000, 29(5): 512-514.
Abstract:
With a special kind of beam with two holes, a substructure method for creation of its finite element model is presented in this paper. The division and discretion of the substructure, the definition of boundary freedom and the forming of reduced model are introduced. According to the requirement of displacement coordination when linking with general beam element, the reduced model is transformed into a special kind of beam element, which has the same number of nodes and the same property of node freedom with general beam element. The substructure modeling method can simplify the model and its calculation greatly.
With a special kind of beam with two holes, a substructure method for creation of its finite element model is presented in this paper. The division and discretion of the substructure, the definition of boundary freedom and the forming of reduced model are introduced. According to the requirement of displacement coordination when linking with general beam element, the reduced model is transformed into a special kind of beam element, which has the same number of nodes and the same property of node freedom with general beam element. The substructure modeling method can simplify the model and its calculation greatly.
2000, 29(5): 515-517.
Abstract:
An efficiency printed circuit board auto testing system using CMOS switch array is presented in this paper. The test Principle and software program manner are also introduced. Through applications,it is shown that the system can ensure the quality of PCB,increase the productivity greatly, and achieve the prospective performance.
An efficiency printed circuit board auto testing system using CMOS switch array is presented in this paper. The test Principle and software program manner are also introduced. Through applications,it is shown that the system can ensure the quality of PCB,increase the productivity greatly, and achieve the prospective performance.
2000, 29(5): 518-521.
Abstract:
In this paper the method of synthetic detection and judgment on truck drive axles assembly is discussed. Entirety performance of truck drive axles assembly is evaluated by parameter values of preload-moment of roller bearings, stiffness and interference of the turning, performance of differential rate etc. The judgment results are given, and the technological improvement is presented. This paper also introduces a test machine designed specially for detection. All kinds of important data of truck drive axles assembly are analyzed and processed by PC. The machine is successfully used in truck drive axles assembly line, whose effect and efficiency are noticeable.
In this paper the method of synthetic detection and judgment on truck drive axles assembly is discussed. Entirety performance of truck drive axles assembly is evaluated by parameter values of preload-moment of roller bearings, stiffness and interference of the turning, performance of differential rate etc. The judgment results are given, and the technological improvement is presented. This paper also introduces a test machine designed specially for detection. All kinds of important data of truck drive axles assembly are analyzed and processed by PC. The machine is successfully used in truck drive axles assembly line, whose effect and efficiency are noticeable.
2000, 29(5): 522-524.
Abstract:
In order to microwave-guide cable draw machine, this paper proposes a scheme, which deals with the design of computer controlling system and the functions of the system. The realization of the functions is also given through software and hardware. Under the control of the single chip microcomputer, the system can perform automatically. The experiment shows that this system is very useful.
In order to microwave-guide cable draw machine, this paper proposes a scheme, which deals with the design of computer controlling system and the functions of the system. The realization of the functions is also given through software and hardware. Under the control of the single chip microcomputer, the system can perform automatically. The experiment shows that this system is very useful.
2000, 29(5): 525-530.
Abstract:
In this paper, the circulation ability, reliability and economical features of the typical topology structures for the fieldbus control system are analyzed. By exploiting GSAGA, the information structure is optimized. A new method for the structure design and analysis of the fieldbus control system are proposed.
In this paper, the circulation ability, reliability and economical features of the typical topology structures for the fieldbus control system are analyzed. By exploiting GSAGA, the information structure is optimized. A new method for the structure design and analysis of the fieldbus control system are proposed.
Study of Electronmagnetic Fields of Nanomicroelectronic Structure Cathod with Autoemitting Electrons
2000, 29(5): 531-534.
Abstract:
This paper presents an improved ALGOL of "Lens". Based on the ALGOL and relative experiments, the characteristics of two kinds of field emitting cathodes are studied, With diameters of pinnacle 101 um. Coefficient of magnification of electronic fields gets to 102. The relationship between the intensity of static electric fields and the Structure of pinnacle are investigated. The influence of roughness of the surface of cathodes is analyzed. The ALGOL and computer program are applicable to nanometer cathodes with any shape.
This paper presents an improved ALGOL of "Lens". Based on the ALGOL and relative experiments, the characteristics of two kinds of field emitting cathodes are studied, With diameters of pinnacle 101 um. Coefficient of magnification of electronic fields gets to 102. The relationship between the intensity of static electric fields and the Structure of pinnacle are investigated. The influence of roughness of the surface of cathodes is analyzed. The ALGOL and computer program are applicable to nanometer cathodes with any shape.
2000, 29(5): 535-539.
Abstract:
This paper mainly discusses the parallel FFT on mesh and hyper-cube which is widely used in parallel computing at present. The hardware distinction, the communication overhead, the system efficiency and the scalability of parallel FFT on those two architectures are studied respectively provd that hyper-cube is much better than mesh for parallel FFT. The result of research shows that the best architecture of the parallel FFT algorithm is hypercube architecture.
This paper mainly discusses the parallel FFT on mesh and hyper-cube which is widely used in parallel computing at present. The hardware distinction, the communication overhead, the system efficiency and the scalability of parallel FFT on those two architectures are studied respectively provd that hyper-cube is much better than mesh for parallel FFT. The result of research shows that the best architecture of the parallel FFT algorithm is hypercube architecture.
2000, 29(5): 540-544.
Abstract:
Based on the dual principle of linear programming, this paper discusses the economic significance of shadow price, corrects the error that interpretes the dual variables as shadow profit, and analyzes the factors that influence shadow price. The function of shadow price in resource allocation is also proposed.
Based on the dual principle of linear programming, this paper discusses the economic significance of shadow price, corrects the error that interpretes the dual variables as shadow profit, and analyzes the factors that influence shadow price. The function of shadow price in resource allocation is also proposed.
2000, 29(5): 545-548.
Abstract:
This paper Studies one unit repairable system with delay repair which has three states:normal, waiting repair and repair. Supposing that the system's life, waiting repair time and repair time have general distribution, using the method of Markov renewal process, a series of reliability indices are obtained such as reliability, unavailability, failure frequency and so on.
This paper Studies one unit repairable system with delay repair which has three states:normal, waiting repair and repair. Supposing that the system's life, waiting repair time and repair time have general distribution, using the method of Markov renewal process, a series of reliability indices are obtained such as reliability, unavailability, failure frequency and so on.
2000, 29(5): 549-551.
Abstract:
In this paper, the finite groups whose automorphism group is a cyclic group or S3 are discussed and the classification of such groups is given. It is proved that the finite groups whose automorphism group is a cyclic group can be classified into four classes.
In this paper, the finite groups whose automorphism group is a cyclic group or S3 are discussed and the classification of such groups is given. It is proved that the finite groups whose automorphism group is a cyclic group can be classified into four classes.
2000, 29(5): 552-555.
Abstract:
The distance of fuzzy numbers is used to define both the fuzzy continuous Auctions and the sequent convergence of fuzzy functions. Their properties are also investigated. The results show that both the sum/difference of fuzzy continuous functions are fuzzy continuous functions and if each term is fuzzy continuous functions in sequence of fuzzy functions, its limit is also fuzzy continuous. In case of consistent continuous functions, integral sign and limit sign are interchangeable, so are differential sign and limit sign.
The distance of fuzzy numbers is used to define both the fuzzy continuous Auctions and the sequent convergence of fuzzy functions. Their properties are also investigated. The results show that both the sum/difference of fuzzy continuous functions are fuzzy continuous functions and if each term is fuzzy continuous functions in sequence of fuzzy functions, its limit is also fuzzy continuous. In case of consistent continuous functions, integral sign and limit sign are interchangeable, so are differential sign and limit sign.
2000, 29(5): 556-559.
Abstract:
This paper studies time-delay neural networks, and establishes the necessary and sufficient condition for the existence and unique of the nerwork's equilibrium point. According to the matrix theory, the method of variations of the parameters and the method of inequality analysis, the sufficient conditions of globally exponential stability of time-delay Hopfield neural networks is established.
This paper studies time-delay neural networks, and establishes the necessary and sufficient condition for the existence and unique of the nerwork's equilibrium point. According to the matrix theory, the method of variations of the parameters and the method of inequality analysis, the sufficient conditions of globally exponential stability of time-delay Hopfield neural networks is established.
2000, 29(5): 560-563.
Abstract:
A problem of the course's time-table is discussed in this paper, and the detail software implementation steps are given. The time-table problem is translated into matrix operation, and the correlative arithmetic is expounded. The arithmetic presented in this paper is very simple and can be implemented conveniently by software. In the end, the correctness and maneuverability of the method are verified.
A problem of the course's time-table is discussed in this paper, and the detail software implementation steps are given. The time-table problem is translated into matrix operation, and the correlative arithmetic is expounded. The arithmetic presented in this paper is very simple and can be implemented conveniently by software. In the end, the correctness and maneuverability of the method are verified.
2000, 29(5): 564-567.
Abstract:
In this paper, a new construction type of membrane electrod——binetwork membrane electrode is suggested, whose catalyst layer is interconnectively composed of catalyst network of Pt/C coated with thin Nafion film having high gas diffusibility and the electrolyte network of carbon coated with thick Nafion film having high proton conductivity. The producing process and conditions of membrane electrode are optimized. The sample of binetwork membrane electrode with 5 cm2 area and 0.1 mg/cm2 Pt contain is obtained.
In this paper, a new construction type of membrane electrod——binetwork membrane electrode is suggested, whose catalyst layer is interconnectively composed of catalyst network of Pt/C coated with thin Nafion film having high gas diffusibility and the electrolyte network of carbon coated with thick Nafion film having high proton conductivity. The producing process and conditions of membrane electrode are optimized. The sample of binetwork membrane electrode with 5 cm2 area and 0.1 mg/cm2 Pt contain is obtained.
