ISSN 
1997 Vol. 26, No. 4
1997, 26(4): 340-346.
Abstract:
This paper analyses an N×N nonblocking ATM input and ouput switch queueing with multiple priorities at input ports.The arrival process of each priority to each input port is Bernoulli with probability p1,p2,…,pR,and each class has a dedicated buffer with infinite size. The speed-up factor is S (B ≤ S ≤ N),and the output buffer size is B with backpressure.Each cell has an equal probability (1/N) being sent to output ports.The average delay time of the considered approaches is derived by theoretical analysis and computer simulations.
This paper analyses an N×N nonblocking ATM input and ouput switch queueing with multiple priorities at input ports.The arrival process of each priority to each input port is Bernoulli with probability p1,p2,…,pR,and each class has a dedicated buffer with infinite size. The speed-up factor is S (B ≤ S ≤ N),and the output buffer size is B with backpressure.Each cell has an equal probability (1/N) being sent to output ports.The average delay time of the considered approaches is derived by theoretical analysis and computer simulations.
1997, 26(4): 347-351.
Abstract:
A novel design method of surface acoustic wave(SAW) bandpass filter is discussed.After resampling at the interval of M,the original desired weighting function is decomposed into two weighting functions with less order by the zero separating of Z-transform,and then represented by interpolation derived from the signal reconstruction theory and can be furtherly suboptimized using the standard Remez change method.The simulation results of a Blackman spectrum-shaping filter with the center frequency of 70 MHz,the roll-off factor of 0.19,0.35 dB ripple,67 dB rejection,confirm that this method is very simple and effective.
A novel design method of surface acoustic wave(SAW) bandpass filter is discussed.After resampling at the interval of M,the original desired weighting function is decomposed into two weighting functions with less order by the zero separating of Z-transform,and then represented by interpolation derived from the signal reconstruction theory and can be furtherly suboptimized using the standard Remez change method.The simulation results of a Blackman spectrum-shaping filter with the center frequency of 70 MHz,the roll-off factor of 0.19,0.35 dB ripple,67 dB rejection,confirm that this method is very simple and effective.
1997, 26(4): 352-356.
Abstract:
This paper discusses a method of determining GPS carrier phase ambiguity in kinematic environments.Mathmactical model is set up.After searching space is defined,all ambiguity combinations are tested with statistic check epoch by epoch until the only correct one is found.Simultaneously accumulated sum of squares of residuals of every ambiguity combination is calculated which can be used to distinguish the correct ambiguity set from the wrong sets easily.Finally simulations are performed which show this algorithm is effective.
This paper discusses a method of determining GPS carrier phase ambiguity in kinematic environments.Mathmactical model is set up.After searching space is defined,all ambiguity combinations are tested with statistic check epoch by epoch until the only correct one is found.Simultaneously accumulated sum of squares of residuals of every ambiguity combination is calculated which can be used to distinguish the correct ambiguity set from the wrong sets easily.Finally simulations are performed which show this algorithm is effective.
1997, 26(4): 357-361.
Abstract:
A modified symbolic coded algorithm (MSCA) for generating symbolic network functions of analog circuits is presented.Comparing with original symbolic coded algorithm (SCA),the new algorithm has simpler coded cell and more accurate definition for coded theorem.So,MSCA can obviously improve computation efficiency and enlarge application ranges.Based on the MSCA,a symbolic network function simulator for analog circuits (SNSAC) is implemented.The main characteristics and construction of the program are introduced.Finally,two application examples for the analog circuits are given.
A modified symbolic coded algorithm (MSCA) for generating symbolic network functions of analog circuits is presented.Comparing with original symbolic coded algorithm (SCA),the new algorithm has simpler coded cell and more accurate definition for coded theorem.So,MSCA can obviously improve computation efficiency and enlarge application ranges.Based on the MSCA,a symbolic network function simulator for analog circuits (SNSAC) is implemented.The main characteristics and construction of the program are introduced.Finally,two application examples for the analog circuits are given.
1997, 26(4): 362-365.
Abstract:
Based on the signal analysis methods and the equivalent to the phase accumulator,the distribution rules of direct digital synthesizer(DDS) with amplitude quantization (ROM truncation) are deduced.The results are agreed with the computer simulation given by the Ref[1],and the DDS' theory is completed.
Based on the signal analysis methods and the equivalent to the phase accumulator,the distribution rules of direct digital synthesizer(DDS) with amplitude quantization (ROM truncation) are deduced.The results are agreed with the computer simulation given by the Ref[1],and the DDS' theory is completed.
1997, 26(4): 366-368.
Abstract:
Segmentation is one of the most important and difficult problems in multidimensional ultrasonic medical image reconstruction.An automatic segmentation method combining the nearest neighbor classifier with self-organization neural network is studied in this paper.In addition to the automatic segmentation benefit,it is proved by experiments that the method exceeds the traditional K-means method in stability,adaptability and exactness etc.
Segmentation is one of the most important and difficult problems in multidimensional ultrasonic medical image reconstruction.An automatic segmentation method combining the nearest neighbor classifier with self-organization neural network is studied in this paper.In addition to the automatic segmentation benefit,it is proved by experiments that the method exceeds the traditional K-means method in stability,adaptability and exactness etc.
1997, 26(4): 370-373.
Abstract:
With the method of physical optics and the uniform geometric theory of diffraction,the scattering matrix of the backscattered field of a finite length coated cylinder is presented.The polarization characteristic and the optimal polarization of the scattered field are analyzed.A example is also given in this paper.
With the method of physical optics and the uniform geometric theory of diffraction,the scattering matrix of the backscattered field of a finite length coated cylinder is presented.The polarization characteristic and the optimal polarization of the scattered field are analyzed.A example is also given in this paper.
1997, 26(4): 374-377.
Abstract:
The natural resonances(poles) of a scattering object are important for the target identification.A new method is proposed in this paper to calculate poles,which points out that the zeros of the fast Fourier transform of the integral kernel function are the poles of the scattering object.As an example,the poles of a thin wire conductor are obtained with high precision in very short time by using this method.
The natural resonances(poles) of a scattering object are important for the target identification.A new method is proposed in this paper to calculate poles,which points out that the zeros of the fast Fourier transform of the integral kernel function are the poles of the scattering object.As an example,the poles of a thin wire conductor are obtained with high precision in very short time by using this method.
1997, 26(4): 378-381.
Abstract:
The conformal mapping and the singular-integral-equation technique are used to derive the expression for the characteristic impedance of a GTEM cell.Simple and very accurate formula for the characteristic impedance based on only spherical TEM mode propagating is found in terms of complete elliptic integrals.The method enables the characteristic impedance of a GTEM cell to be evaluated accurately and easily.In addition,a simple method,i.e., a combination of conformal mapping and the method of finite difference is suggested to be used in the study of the electromagnetic field distribution of spherical TEM mode and the characteristics of the higher modes in the GTEM cell.The analysis is useful in the study of GTEM cells and broadband transmission lines.
The conformal mapping and the singular-integral-equation technique are used to derive the expression for the characteristic impedance of a GTEM cell.Simple and very accurate formula for the characteristic impedance based on only spherical TEM mode propagating is found in terms of complete elliptic integrals.The method enables the characteristic impedance of a GTEM cell to be evaluated accurately and easily.In addition,a simple method,i.e., a combination of conformal mapping and the method of finite difference is suggested to be used in the study of the electromagnetic field distribution of spherical TEM mode and the characteristics of the higher modes in the GTEM cell.The analysis is useful in the study of GTEM cells and broadband transmission lines.
1997, 26(4): 382-386.
Abstract:
In thip paper,a method for determination of microwave transistor parameter is described.An automated measurement system for microwave transistor noise parameter is constructed using vector network analyzer and noise figure meter.With the control software,the system can do fast and accurate measurements.Some test results for GaAs FET are given and compared with typical data given by the manufacturer.
In thip paper,a method for determination of microwave transistor parameter is described.An automated measurement system for microwave transistor noise parameter is constructed using vector network analyzer and noise figure meter.With the control software,the system can do fast and accurate measurements.Some test results for GaAs FET are given and compared with typical data given by the manufacturer.
1997, 26(4): 387-390.
Abstract:
After reviewing the characteristics of the alumina film capactiance humidity sensors,a new alumina film humidity sensor employing α Alumina film is suggested.The fabrication method and primary characteristics are described in this paper.Finally,those problems that have not been solved are discussed.
After reviewing the characteristics of the alumina film capactiance humidity sensors,a new alumina film humidity sensor employing α Alumina film is suggested.The fabrication method and primary characteristics are described in this paper.Finally,those problems that have not been solved are discussed.
1997, 26(4): 391-393.
Abstract:
With no preformatted servo groove structure and simple linear moving instead of conventional disc rotation,a new erasable magneto optical card (MOC) is presented.Its data are written in tracks which are parallel to the width of the card.It possesses the advantages of MO disc erasability and optical card portability.As the defocus tolerance of ±10 μm for focus servo system is set up,the MOC storage system is low-cost and has a good potential markets in medium capacity storage fields.
With no preformatted servo groove structure and simple linear moving instead of conventional disc rotation,a new erasable magneto optical card (MOC) is presented.Its data are written in tracks which are parallel to the width of the card.It possesses the advantages of MO disc erasability and optical card portability.As the defocus tolerance of ±10 μm for focus servo system is set up,the MOC storage system is low-cost and has a good potential markets in medium capacity storage fields.
1997, 26(4): 394-397.
Abstract:
Telluret thin films are prepared by sintering and the vacuum evaporation techniques.The effects of fabrication enviroments on the characteristics of CdTe thin films are developed and the experimental results show that the thin films fabricated at about 130℃ substrate temperature have obviously optoelectronic effects and the band gap of CdTe thin films is about 1.63 eV at room temperature.The substrates of CdTe thin films are determined by X ray diffratograms.
Telluret thin films are prepared by sintering and the vacuum evaporation techniques.The effects of fabrication enviroments on the characteristics of CdTe thin films are developed and the experimental results show that the thin films fabricated at about 130℃ substrate temperature have obviously optoelectronic effects and the band gap of CdTe thin films is about 1.63 eV at room temperature.The substrates of CdTe thin films are determined by X ray diffratograms.
1997, 26(4): 398-401.
Abstract:
In the process of preparing Ta/Al alloy resistance thin films with DC co-sputtering,the influence of the main technological parameters such as -target substrate distance,gas pressure,sputtering voltage and heat-treatment time etc.on the temperature coefficient of resistance (TCR) of the films is investigated.The methods of square-error analysis and orthogonal experiment are suggested for obtaining optimal process condition and TCR of the films.The results show that Ta/Al alloy thin films with ideal TCR characteristic can be prepared,as long as the four part main technological parameter is selected and controlled properly.At the same time,the effectiveness of the method of square-error analysis is proved.
In the process of preparing Ta/Al alloy resistance thin films with DC co-sputtering,the influence of the main technological parameters such as -target substrate distance,gas pressure,sputtering voltage and heat-treatment time etc.on the temperature coefficient of resistance (TCR) of the films is investigated.The methods of square-error analysis and orthogonal experiment are suggested for obtaining optimal process condition and TCR of the films.The results show that Ta/Al alloy thin films with ideal TCR characteristic can be prepared,as long as the four part main technological parameter is selected and controlled properly.At the same time,the effectiveness of the method of square-error analysis is proved.
1997, 26(4): 402-404.
Abstract:
In this paper,the influences of earthquake overturning momeat on loading satates of frame beam are studied for bearing walls being put on subordinate beams in masonry buildings with ground frame floor.Based on the supposition that the subordinate beam acted by the earthquake overturning moment would turn as a rigid body,the paper presents calculation formulas of vertical force applied on the frame beams by the earthquake overturning moment.
In this paper,the influences of earthquake overturning momeat on loading satates of frame beam are studied for bearing walls being put on subordinate beams in masonry buildings with ground frame floor.Based on the supposition that the subordinate beam acted by the earthquake overturning moment would turn as a rigid body,the paper presents calculation formulas of vertical force applied on the frame beams by the earthquake overturning moment.
1997, 26(4): 405-408.
Abstract:
A neural network expert system approach for analog IC fault diagnosis is presented in this paper,which takes advantage of the two technologies (neural network and expert system) complementary abilities to solve diagnostic problems,and has the features of rapid development,accurate diagnosis and cost-effective maintenance.It provides an efficient way for analog IC fault diagnosis.The architecture and implement techniques are discussed in detail.Experimental results shows the feasibility of the method.
A neural network expert system approach for analog IC fault diagnosis is presented in this paper,which takes advantage of the two technologies (neural network and expert system) complementary abilities to solve diagnostic problems,and has the features of rapid development,accurate diagnosis and cost-effective maintenance.It provides an efficient way for analog IC fault diagnosis.The architecture and implement techniques are discussed in detail.Experimental results shows the feasibility of the method.
1997, 26(4): 409-413.
Abstract:
A processing of dry kiln is introduced.Some in problems controlling of the stability of thermoengineering system are discussed.This paper also advances a new decoupling method,which successfully settles the relation between principal parameters under normal environment and a controlling strategy.An expert system is employed to solve some abnoramal problems.Finally,the computer simulation and the on-the-spot analysis show the method is absdutely feasible.
A processing of dry kiln is introduced.Some in problems controlling of the stability of thermoengineering system are discussed.This paper also advances a new decoupling method,which successfully settles the relation between principal parameters under normal environment and a controlling strategy.An expert system is employed to solve some abnoramal problems.Finally,the computer simulation and the on-the-spot analysis show the method is absdutely feasible.
1997, 26(4): 414-419.
Abstract:
The criteria of the optimal sampling frequency is deduced by optimally indentfing the modal parameters according to the nature of the forcing fuction,and the related principles and formulae are given.The computation example shows that the optimal sampling frequency is independent of the system response,and solely depend on the nature of the excitation.
The criteria of the optimal sampling frequency is deduced by optimally indentfing the modal parameters according to the nature of the forcing fuction,and the related principles and formulae are given.The computation example shows that the optimal sampling frequency is independent of the system response,and solely depend on the nature of the excitation.
1997, 26(4): 420-425.
Abstract:
The experimental research and analysis of 1.31 μm single-mode channel waveguides and components fabricated by annealed proton exchanged (APE) technique in X cut,Y proagation LiNbO3 are presented.The near field mode intensity profile of optical waveguides under various proton exchange time (te) and annealed time (ta) are measured.The optical waveguide mode size matching well with singlemode fibre is obtained by measuring and comparing with that of a single mode fiber.The lowest insertion loss of fibre waveguide fibre is 3.2 dB.The low frequency modulation characteristics of M Z interferometric modulator modulator formed in APE waveguides are tested.
The experimental research and analysis of 1.31 μm single-mode channel waveguides and components fabricated by annealed proton exchanged (APE) technique in X cut,Y proagation LiNbO3 are presented.The near field mode intensity profile of optical waveguides under various proton exchange time (te) and annealed time (ta) are measured.The optical waveguide mode size matching well with singlemode fibre is obtained by measuring and comparing with that of a single mode fiber.The lowest insertion loss of fibre waveguide fibre is 3.2 dB.The low frequency modulation characteristics of M Z interferometric modulator modulator formed in APE waveguides are tested.
1997, 26(4): 426-430.
Abstract:
The photoelectric transformation technology in equivalent measurement of nuclear explosion in atomsphere is discussed in this paper.The nonlinear load of resistor-diode parallel and multistage cascade is given,and the load design for photoelectric transducer with large dynamic range and anti-saturability characteristics is proposed in the measurement of ray radiation of nuclear explosion,which is anti -valley-sautrated and antinoised to the sunlight background.
The photoelectric transformation technology in equivalent measurement of nuclear explosion in atomsphere is discussed in this paper.The nonlinear load of resistor-diode parallel and multistage cascade is given,and the load design for photoelectric transducer with large dynamic range and anti-saturability characteristics is proposed in the measurement of ray radiation of nuclear explosion,which is anti -valley-sautrated and antinoised to the sunlight background.
1997, 26(4): 431-434.
Abstract:
A new method on simplification of the logic function is introduced in this paper.The method is to find the primitive implicant by seeking the minimum of the eliminable variable,to find the essential implicant by analysing the inclusion of the minimum,and to simplify the function more than tetravariable by resolving the variables.The method makes the simplification of the multi variable exactly and rapidly.The simplification data of the examples are also given.
A new method on simplification of the logic function is introduced in this paper.The method is to find the primitive implicant by seeking the minimum of the eliminable variable,to find the essential implicant by analysing the inclusion of the minimum,and to simplify the function more than tetravariable by resolving the variables.The method makes the simplification of the multi variable exactly and rapidly.The simplification data of the examples are also given.
1997, 26(4): 435-439.
Abstract:
As the acidemic foundmental of computer science,formal language and automatic machine theory are important for specification and analysis of programming language.The element principle of formal language and automatic machine are introduced in this paper.Then the defination of the context-free gramma,context sensitive gramma,and their relative language are given.The relationship between them is also dicussed.
As the acidemic foundmental of computer science,formal language and automatic machine theory are important for specification and analysis of programming language.The element principle of formal language and automatic machine are introduced in this paper.Then the defination of the context-free gramma,context sensitive gramma,and their relative language are given.The relationship between them is also dicussed.
1997, 26(4): 440-444.
Abstract:
The topological degree theory has important value in the sense that it gives information about the number of distinct solutions,continuous families of solutions and stability of solutions[1].Recently,the solvability of the operator equation y∈(A+C)x was discussed by means of topological degree theory[2,3].In this paper,a generalized degree for maccretive operator A perturbed by condensing mapping C is established,and an useful tool for solving the operator equation y∈(A+C)x is supplied.
The topological degree theory has important value in the sense that it gives information about the number of distinct solutions,continuous families of solutions and stability of solutions[1].Recently,the solvability of the operator equation y∈(A+C)x was discussed by means of topological degree theory[2,3].In this paper,a generalized degree for maccretive operator A perturbed by condensing mapping C is established,and an useful tool for solving the operator equation y∈(A+C)x is supplied.
1997, 26(4): 445-448.
Abstract:
In this paper,the gradient projection and penalty function are used to make optimization problems for inequality and equality constraints into optimization problems without constraints.An algorithm of perturbed gradient projection for inequality and equality constrained problems is given.Considering the error of calculating and perturbing in search direction,a gradient projection method for inexact search direction is produced,which can get a sort of gradient projection algorithm when parameter Wk is differently chosed.The algorithm is globally convergent under very weak conditions.
In this paper,the gradient projection and penalty function are used to make optimization problems for inequality and equality constraints into optimization problems without constraints.An algorithm of perturbed gradient projection for inequality and equality constrained problems is given.Considering the error of calculating and perturbing in search direction,a gradient projection method for inexact search direction is produced,which can get a sort of gradient projection algorithm when parameter Wk is differently chosed.The algorithm is globally convergent under very weak conditions.
1997, 26(4): 449-452.
Abstract:
Based on Ref.1 and 2,E.Hille-E.Yosida or Goldstein operation (semigroup)group is considered in this paper.A distrurbed linear operation semigroup is discussed which processes convergent operator in norm,stiff continuous,and sole and differential characteristics.The relationship between disturbed linear operation semigroup and 4-order feedback evolution equation is presented in a view of generating operator.
Based on Ref.1 and 2,E.Hille-E.Yosida or Goldstein operation (semigroup)group is considered in this paper.A distrurbed linear operation semigroup is discussed which processes convergent operator in norm,stiff continuous,and sole and differential characteristics.The relationship between disturbed linear operation semigroup and 4-order feedback evolution equation is presented in a view of generating operator.
