ISSN 
1997 Vol. 26, No. 3
1997, 26(3): 225-231.
Abstract:
In this paper,the traffic model and the performance analysis for multi-point and multi-class teleconferencing network are studied.The knapsack model is used to analyze the blocking probability performance of the teleconferencing networks.In the teleconferencing traffic model,an array of video services ranging from lower to higher quality is assumed.The star network topology is considered in this paper.An illustrative example is provided.
In this paper,the traffic model and the performance analysis for multi-point and multi-class teleconferencing network are studied.The knapsack model is used to analyze the blocking probability performance of the teleconferencing networks.In the teleconferencing traffic model,an array of video services ranging from lower to higher quality is assumed.The star network topology is considered in this paper.An illustrative example is provided.
1997, 26(3): 232-235,248.
Abstract:
In this paper,the application of cross-interleaved reed-solomon code (CIRC) in rotary head digiatl magnetic recorder is discussed.The elemental method on coding and decoding of RS code in time domain is presented,and the hardwave implementation of CIRC encoder/decoder with FPGA and L6471X Sery VLSI is given.Experiment shows that by adding CIRC ECC (error-correcting circuit),the BER (bit-error-rate) can be decreased from 10-3 to less that 10-8.Finally,the reason for error is analysed.
In this paper,the application of cross-interleaved reed-solomon code (CIRC) in rotary head digiatl magnetic recorder is discussed.The elemental method on coding and decoding of RS code in time domain is presented,and the hardwave implementation of CIRC encoder/decoder with FPGA and L6471X Sery VLSI is given.Experiment shows that by adding CIRC ECC (error-correcting circuit),the BER (bit-error-rate) can be decreased from 10-3 to less that 10-8.Finally,the reason for error is analysed.
1997, 26(3): 236-239.
Abstract:
Two dimension(range and azimuth)radar image can be obtained by a new kind of image radar system called radio camera.After the comparlsion between one dimension rage profile and two dimension (range and azinuth)radar image,the advangtage of the two dimension radar image in the field of the automatic target recognition is pointed out in this paper.The analysis is confirmed by computer simulation results.
Two dimension(range and azimuth)radar image can be obtained by a new kind of image radar system called radio camera.After the comparlsion between one dimension rage profile and two dimension (range and azinuth)radar image,the advangtage of the two dimension radar image in the field of the automatic target recognition is pointed out in this paper.The analysis is confirmed by computer simulation results.
1997, 26(3): 240-243.
Abstract:
Dielectric radome has usually an effect on antenna radiation properties and distrots the antenna patterns.In this paper,the pattern of array antenna is simulated by superposition of complex source point beam fields,and the complex ray theory is used to analyze the influence of radome on antenna radiation properties.Conclusions obtained are helpful for combined design of array antenna and radome.
Dielectric radome has usually an effect on antenna radiation properties and distrots the antenna patterns.In this paper,the pattern of array antenna is simulated by superposition of complex source point beam fields,and the complex ray theory is used to analyze the influence of radome on antenna radiation properties.Conclusions obtained are helpful for combined design of array antenna and radome.
1997, 26(3): 244-248.
Abstract:
After comparing the existing techniques of diffraction analysis of SAW-IDT,this paper presents a new broadband analysis method.Begining with the charge distribution and Green function,this paper derivates the rigorous angular spectrum of wave and impulse-response model,the substrate anisotropy and propagation character are included,and the broadband analysis of diffraction in frequency domain is given.The simulation proves that this method is very precise and can be used in design and compensation of high performance wideband SAW filters.
After comparing the existing techniques of diffraction analysis of SAW-IDT,this paper presents a new broadband analysis method.Begining with the charge distribution and Green function,this paper derivates the rigorous angular spectrum of wave and impulse-response model,the substrate anisotropy and propagation character are included,and the broadband analysis of diffraction in frequency domain is given.The simulation proves that this method is very precise and can be used in design and compensation of high performance wideband SAW filters.
1997, 26(3): 249-253.
Abstract:
In this paper,the distorted born iterative method(DBIM) is applied to deal with the inversion problem of the short normal device measurements in two-dimensional axisymmetric medium.In each iteration of the DBIM,an effiecient-half analytical half numerical method is used to solve the problem.This method provides a semianlytic expression for the Green's function and its derivatives required in the inversion,and then deduces a semianalytic expression of the integration in the nonlinear intergral equation.Therefore,the efficiency and accuracy are improved dramatically.
In this paper,the distorted born iterative method(DBIM) is applied to deal with the inversion problem of the short normal device measurements in two-dimensional axisymmetric medium.In each iteration of the DBIM,an effiecient-half analytical half numerical method is used to solve the problem.This method provides a semianlytic expression for the Green's function and its derivatives required in the inversion,and then deduces a semianalytic expression of the integration in the nonlinear intergral equation.Therefore,the efficiency and accuracy are improved dramatically.
1997, 26(3): 254-257.
Abstract:
In this papar,a new idea about the laterolog resistivity tool,namely the hybrid laterolog resistivity tool is intrduced.The efficient numerical mode-matching method(NMM) combineing with surface integral equation method can match the complex excited condition,and the hybrid laterolog respone is rapidly calculated in a complex media.The result from the numerical stimuluion shows that it has superior vertical resolution and deeper radial measuring depth than regular dual laterolog tool.
In this papar,a new idea about the laterolog resistivity tool,namely the hybrid laterolog resistivity tool is intrduced.The efficient numerical mode-matching method(NMM) combineing with surface integral equation method can match the complex excited condition,and the hybrid laterolog respone is rapidly calculated in a complex media.The result from the numerical stimuluion shows that it has superior vertical resolution and deeper radial measuring depth than regular dual laterolog tool.
1997, 26(3): 258-261.
Abstract:
In this paper,a new type of circular-shaped microshield and conductor-backed coplanar waveguide (CPW) is proposed.Analytical closed form expressions for characteristic impedance and effective dielectric constant for the new line are obtained using conformal mapping method under the assumption of pure-TEM propagation and zero dispersion.The new waveguide proposed by this paper and reduce radiation to much less than the conventional CPW and microstrip,and reduce the current concentration at both the edges of the signal,and has no need for viaholes or air-bridges for ground equalization and a wide range of impedances.
In this paper,a new type of circular-shaped microshield and conductor-backed coplanar waveguide (CPW) is proposed.Analytical closed form expressions for characteristic impedance and effective dielectric constant for the new line are obtained using conformal mapping method under the assumption of pure-TEM propagation and zero dispersion.The new waveguide proposed by this paper and reduce radiation to much less than the conventional CPW and microstrip,and reduce the current concentration at both the edges of the signal,and has no need for viaholes or air-bridges for ground equalization and a wide range of impedances.
1997, 26(3): 262-266.
Abstract:
GPS integrity monitoring problem must be solved in GPS navigation.This paper discusses in detail the FDI and FR problems with parity vector method using the likelihood rate's point of view.At last,sudden failures and soft failures with GPS satellites are considered in simulations respectively,and the results show the reasonableness of the parity vector method.This method provides rationale basis for the implementation of RAIM.
GPS integrity monitoring problem must be solved in GPS navigation.This paper discusses in detail the FDI and FR problems with parity vector method using the likelihood rate's point of view.At last,sudden failures and soft failures with GPS satellites are considered in simulations respectively,and the results show the reasonableness of the parity vector method.This method provides rationale basis for the implementation of RAIM.
1997, 26(3): 267-272.
Abstract:
DCT is an orthogonal transformation widely used in image compression applications.Because of its high computational cost,the operating speed of DCT will be a key factor in the case where real-time processing are required.TMS320C80(MVP) is a recently developed general purpose programmable digital signal processor,which can operate in both SIMD and MIMD concurrent-modes.This paper presents the fast algorithms of DCT and the advantages of TMS320C80 architecture,and discusses the parallel strategy of 2D DCT on MVP.The speedups of SIMD and MIMD modes are compared.Finally,Lee's fast algorithm is chosen and mapped onto MVP with SIMD mode.The results show that the implemention can meet the requirements of real-time applications.
DCT is an orthogonal transformation widely used in image compression applications.Because of its high computational cost,the operating speed of DCT will be a key factor in the case where real-time processing are required.TMS320C80(MVP) is a recently developed general purpose programmable digital signal processor,which can operate in both SIMD and MIMD concurrent-modes.This paper presents the fast algorithms of DCT and the advantages of TMS320C80 architecture,and discusses the parallel strategy of 2D DCT on MVP.The speedups of SIMD and MIMD modes are compared.Finally,Lee's fast algorithm is chosen and mapped onto MVP with SIMD mode.The results show that the implemention can meet the requirements of real-time applications.
1997, 26(3): 273-278.
Abstract:
Based on static priority scheduling algorithm in hard real-time multitask system,and incorporating other time overhead besides execution time of the tasks,for example,tasks synchronization interruption processsing,this paper quantitativly analyses the influence of time parameters upon tasks deadline,and presents a method used to calculate whether a task can be completed within specified deadline.The method treats timm-out as a kind of fault,then gets the probability of time-out fault occurring,and provides a quantified means for evaluating real-time feature.
Based on static priority scheduling algorithm in hard real-time multitask system,and incorporating other time overhead besides execution time of the tasks,for example,tasks synchronization interruption processsing,this paper quantitativly analyses the influence of time parameters upon tasks deadline,and presents a method used to calculate whether a task can be completed within specified deadline.The method treats timm-out as a kind of fault,then gets the probability of time-out fault occurring,and provides a quantified means for evaluating real-time feature.
1997, 26(3): 279-282.
Abstract:
The limited-handwritten chinese character is discussed in this paper.The preprocessing method is proposed.The limited-handwritten chinese character is produced by pickup camcra.The proposing algorithms for chinese is a method combining regular position,regular big small,level and smooth processing,slender processing.The recognition rate is raised greatly for chinese character.
The limited-handwritten chinese character is discussed in this paper.The preprocessing method is proposed.The limited-handwritten chinese character is produced by pickup camcra.The proposing algorithms for chinese is a method combining regular position,regular big small,level and smooth processing,slender processing.The recognition rate is raised greatly for chinese character.
1997, 26(3): 283-288.
Abstract:
This paper discusses some critical issues in computer virus countermeasures (CVCM).The computer virus (including rogue programs)at present in the computer and network system is introduced.It will also be inclined to research in electronic warfare (EW) and become a potential or great meance to both civil and military network or information systems.The common and difference grounds between computer virus countermeasure and electronic countermeasure are discussed.The knowledge and issues of attacking and protection of CVCM,the virus and anti virus techniques are also shown.
This paper discusses some critical issues in computer virus countermeasures (CVCM).The computer virus (including rogue programs)at present in the computer and network system is introduced.It will also be inclined to research in electronic warfare (EW) and become a potential or great meance to both civil and military network or information systems.The common and difference grounds between computer virus countermeasure and electronic countermeasure are discussed.The knowledge and issues of attacking and protection of CVCM,the virus and anti virus techniques are also shown.
1997, 26(3): 289-292.
Abstract:
This paper presents a fuzzy adaptive variable weighting algorithm for combination forecasting by imitating men's decision-making process.The algorithm adapts the weighting of each method according to its match-degree with the real value during the last period of time.So,it is a variable weighting algorithm for combination forecasting.Simulation results show that the algorithm is simple and effective,and has good performance of tracking ability.
This paper presents a fuzzy adaptive variable weighting algorithm for combination forecasting by imitating men's decision-making process.The algorithm adapts the weighting of each method according to its match-degree with the real value during the last period of time.So,it is a variable weighting algorithm for combination forecasting.Simulation results show that the algorithm is simple and effective,and has good performance of tracking ability.
1997, 26(3): 293-297.
Abstract:
By using characteristic analysis of economic structure coefficient matrix in input output analysis,two theoretical optimum industry structures in a sense final products and social pure income (profit and tax) are studied.The relationship of those two optimum structures is discussed.
By using characteristic analysis of economic structure coefficient matrix in input output analysis,two theoretical optimum industry structures in a sense final products and social pure income (profit and tax) are studied.The relationship of those two optimum structures is discussed.
1997, 26(3): 298-302.
Abstract:
From the starting of the queue length process itself,this paper directly studies the distribution of the queue length in the M/G/1/∞ queueing model by using the Laplace transform tool.The recursion express of the Laplace transform of the transient queue length distribution at any time t and the recursion formula of the equilibrium distribution for calculating conveniently are obtained.At last some more useful recursion formulas for calculating are given in several special queueing models.
From the starting of the queue length process itself,this paper directly studies the distribution of the queue length in the M/G/1/∞ queueing model by using the Laplace transform tool.The recursion express of the Laplace transform of the transient queue length distribution at any time t and the recursion formula of the equilibrium distribution for calculating conveniently are obtained.At last some more useful recursion formulas for calculating are given in several special queueing models.
1997, 26(3): 303-307.
Abstract:
In this paper,soml problems of counting the n umber of m level digital sequlnces of length n that satisfy some constraints are considered and their recursive formulas and explicit formulations arl given.A result of combinatorial lnumlration of kly codlwords is improved and some combinatorial identical relations are got.
In this paper,soml problems of counting the n umber of m level digital sequlnces of length n that satisfy some constraints are considered and their recursive formulas and explicit formulations arl given.A result of combinatorial lnumlration of kly codlwords is improved and some combinatorial identical relations are got.
1997, 26(3): 308-313.
Abstract:
As for the stability of control system,it has been further studied in Ref.,and great achievements have been got.In this paper,the inequlity is used to analyse and study the absolute stability of control system.Some criteria for stability are obtained.The conditions are all based on the parameters of the system itself,thus are easy to apply.The equation of vertical plane movement is given as an example to illustrate the advantages of the obtained achievements.
As for the stability of control system,it has been further studied in Ref.,and great achievements have been got.In this paper,the inequlity is used to analyse and study the absolute stability of control system.Some criteria for stability are obtained.The conditions are all based on the parameters of the system itself,thus are easy to apply.The equation of vertical plane movement is given as an example to illustrate the advantages of the obtained achievements.
1997, 26(3): 314-317.
Abstract:
It is pointed out theoretically that the prototype drop in microstrip junction circulators (or isolators) without excellent operating characteristics are due to unsatisfaction of the second circulation condition.It is proposed that the impedance matching condition can be improved by changing the height of the centre junction and length of matching sections,which lead to the improvement of the operating characteristics of the devices.A drop in isolator that operates in Ka band is obtained,which exhibits less than 1 dB insertion loss and greater than 20 dB isolation in 2.0 GHz absolute bandwidth(30.5~32.5 GHz).
It is pointed out theoretically that the prototype drop in microstrip junction circulators (or isolators) without excellent operating characteristics are due to unsatisfaction of the second circulation condition.It is proposed that the impedance matching condition can be improved by changing the height of the centre junction and length of matching sections,which lead to the improvement of the operating characteristics of the devices.A drop in isolator that operates in Ka band is obtained,which exhibits less than 1 dB insertion loss and greater than 20 dB isolation in 2.0 GHz absolute bandwidth(30.5~32.5 GHz).
1997, 26(3): 318-323.
Abstract:
The sensitivity,selectivity,accuracy and separability for the image pre-processing circuit of multi-sensor system are analysed completely and the upper bounds of the accuracy and sparability are obtained using the matrix norm.Those bounds expose the relations among the accuracy and separability,the condition number (Cond(b)) and deviation Wb of the design matrix and the diturbing random variable X,Which shows that the estimate of the accuracy can be restricted to a certain level by the control of Cond(b), W and X.
The sensitivity,selectivity,accuracy and separability for the image pre-processing circuit of multi-sensor system are analysed completely and the upper bounds of the accuracy and sparability are obtained using the matrix norm.Those bounds expose the relations among the accuracy and separability,the condition number (Cond(b)) and deviation Wb of the design matrix and the diturbing random variable X,Which shows that the estimate of the accuracy can be restricted to a certain level by the control of Cond(b), W and X.
1997, 26(3): 324-327.
Abstract:
A test pattern generation system implemented with neural network method is introduced in this paper.The system consist of circuit description,preprocessing,the build of neural network,test pattern generation and test informations module.A lot of strategies are discussed to improve the performances of the method,such as the selection of constrained network that accords with the circuit under test,evaluating the values of neurons,circuit partition,the selection of optimization algorithms.Some problems in the test pattern generation method based on neural network is presented and discussed.The experimental results indicate the test system is effective.
A test pattern generation system implemented with neural network method is introduced in this paper.The system consist of circuit description,preprocessing,the build of neural network,test pattern generation and test informations module.A lot of strategies are discussed to improve the performances of the method,such as the selection of constrained network that accords with the circuit under test,evaluating the values of neurons,circuit partition,the selection of optimization algorithms.Some problems in the test pattern generation method based on neural network is presented and discussed.The experimental results indicate the test system is effective.
1997, 26(3): 328-332.
Abstract:
Development of courseware has become a bottleneck against the evolement and generalization of CAI(Computer Aided Instruction).It is one of the effective way to research and develop courseware authoring system in order to improve courseware productivity and quality.Multimedia courseware authoring system which combines multimedia technology and computer aided instruction gives users an effective authoring environment.This paper gives the construction of one multimedia courseware authoring system(FA MCAS),including the design and implication.
Development of courseware has become a bottleneck against the evolement and generalization of CAI(Computer Aided Instruction).It is one of the effective way to research and develop courseware authoring system in order to improve courseware productivity and quality.Multimedia courseware authoring system which combines multimedia technology and computer aided instruction gives users an effective authoring environment.This paper gives the construction of one multimedia courseware authoring system(FA MCAS),including the design and implication.
1997, 26(3): 333-336.
Abstract:
The electroreduction of 1,2,4-trihydroxyanthraquinone-3 carboxylic acid on the dropping mercury electrode (DME) is investigated.The research results of polarogram of the electroactive reagent show that at pH=3.9 the electrode process of one wave E1/2=-0.47V/SCE is controlled by diffusione.The electroactive reagent on DME needs two electrons and one hydrogen ion to produce the respective hydroquinone.The polarograhpy method can be used to analysis the concentration of the electroactive reagent.One possible reaction mechanism is proposed.
The electroreduction of 1,2,4-trihydroxyanthraquinone-3 carboxylic acid on the dropping mercury electrode (DME) is investigated.The research results of polarogram of the electroactive reagent show that at pH=3.9 the electrode process of one wave E1/2=-0.47V/SCE is controlled by diffusione.The electroactive reagent on DME needs two electrons and one hydrogen ion to produce the respective hydroquinone.The polarograhpy method can be used to analysis the concentration of the electroactive reagent.One possible reaction mechanism is proposed.
1997, 26(3): 337-339.
Abstract:
In this paper,the characteristics of scientific and technical periodicals are discussed,which are the basis of the existence of scientific and technical periodicals.It is pointed out that the completion and the improvement of scientific and technical periodicals are the soul in the editing.
In this paper,the characteristics of scientific and technical periodicals are discussed,which are the basis of the existence of scientific and technical periodicals.It is pointed out that the completion and the improvement of scientific and technical periodicals are the soul in the editing.
