ISSN 
1997 Vol. 26, No. 2
1997, 26(2): 113-116.
Abstract:
Fractal methods open up great prospects for many image processing areas.In this paper fractal inage coding and fractal interpolation are studied at first,then an efficient image compression method combining fractal interpolation and fractal image coding is proposed.The shortcoming of the common fractal image compression methods is that it is time-consuming.The new method reduces compression time greatly.The compression result shows that the compression is as high as 76 to 1 while PSNR is 28.7dB.The high copmression is very useful for image communication.
Fractal methods open up great prospects for many image processing areas.In this paper fractal inage coding and fractal interpolation are studied at first,then an efficient image compression method combining fractal interpolation and fractal image coding is proposed.The shortcoming of the common fractal image compression methods is that it is time-consuming.The new method reduces compression time greatly.The compression result shows that the compression is as high as 76 to 1 while PSNR is 28.7dB.The high copmression is very useful for image communication.
1997, 26(2): 117-120.
Abstract:
How to detect the edges of image is a very interesting subject.The wavelet trans-form is a very useful tool for signal processing,especially the multiresolution represention are very effective for analyzing the information content of signals.This paper utilizes the property of the wavelet transform and edges,based on the theory of Mallat's characterization of signals from multiscales edges and discusses the method of characterization of signals from multiscales edges about M-band wavelet transform.Using the method,the edges of image can be detected.Experimental results are given,which show that the algorithm is simple,reliable and very useful for detecting edges of image.
How to detect the edges of image is a very interesting subject.The wavelet trans-form is a very useful tool for signal processing,especially the multiresolution represention are very effective for analyzing the information content of signals.This paper utilizes the property of the wavelet transform and edges,based on the theory of Mallat's characterization of signals from multiscales edges and discusses the method of characterization of signals from multiscales edges about M-band wavelet transform.Using the method,the edges of image can be detected.Experimental results are given,which show that the algorithm is simple,reliable and very useful for detecting edges of image.
1997, 26(2): 121-125.
Abstract:
Surface acoustic wave (SAW) oscillator is a kind of typical feedback oscillators with feedback elements.Its phase noise characteristics is analyzed in the context of Leeson's model of feedback oscillator phase noise and particular attention is given to the cases of different feedback SAW elements,since different feedback elements ordinarily denote different phase noise characteristics in the view of our points in this paper.Approaches and methods for reducing phase noise levels are discussed along with an analysis of reported attempts to obtain improved spectral purity.
Surface acoustic wave (SAW) oscillator is a kind of typical feedback oscillators with feedback elements.Its phase noise characteristics is analyzed in the context of Leeson's model of feedback oscillator phase noise and particular attention is given to the cases of different feedback SAW elements,since different feedback elements ordinarily denote different phase noise characteristics in the view of our points in this paper.Approaches and methods for reducing phase noise levels are discussed along with an analysis of reported attempts to obtain improved spectral purity.
1997, 26(2): 126-131.
Abstract:
A new symbolic coded algorithm NSCA of generating symbolic network functions is presents.In NSCA,the base code of coded cell prescribed each component is much lower,so it prevents early orerflow of integer.The scale of the circuit analyzed then can be larger.It also provides sensitivity algorithm and simplify algorithm,and processes a circuit with definite function as a model circuit,which enlarge the application.A computer program SNSPC2.0 (symbolic network simulation by parameter coded)which is based on NSCA is developed,and its effectiveness is illstrated with examples.
A new symbolic coded algorithm NSCA of generating symbolic network functions is presents.In NSCA,the base code of coded cell prescribed each component is much lower,so it prevents early orerflow of integer.The scale of the circuit analyzed then can be larger.It also provides sensitivity algorithm and simplify algorithm,and processes a circuit with definite function as a model circuit,which enlarge the application.A computer program SNSPC2.0 (symbolic network simulation by parameter coded)which is based on NSCA is developed,and its effectiveness is illstrated with examples.
1997, 26(2): 137-142.
Abstract:
Based on rigious signal analysis,some spectrum expressions of direct digital synthesizer (DDS) are presented by employing discrete Fourier transform (DFT) and Fourier transform (FT) in this paper.First,the output characteristics of DDS with ideal parameters are discussed.Then,the distribution and amplitude of output spectrum of DDS are provided in the presence of phase accumulator truncation in details.The deduced results are quite in agreement with general-recognized ones.The conclusion is useful for real DDS System design.
Based on rigious signal analysis,some spectrum expressions of direct digital synthesizer (DDS) are presented by employing discrete Fourier transform (DFT) and Fourier transform (FT) in this paper.First,the output characteristics of DDS with ideal parameters are discussed.Then,the distribution and amplitude of output spectrum of DDS are provided in the presence of phase accumulator truncation in details.The deduced results are quite in agreement with general-recognized ones.The conclusion is useful for real DDS System design.
1997, 26(2): 143-147.
Abstract:
On the basis of the principle of "electronically tuning fundamental frequency and extracting second harmonic",this paper proposes a circuit model for wideband series varactor tuned harmonic oscillators.At W-band electronic tuned bandwidth of 15% is achieved within which the minimum power is 5 mW and the maximum over 17 mW.Electronic tuned bandwidth of 13 GHz over 5 mW is obtained.Applying these oscillators,this paper develops electronically tuning signal generators at W-band.Operating bandwidth of signal generators is 10 GHz,frequency error less than 100 MHz,frequency stability (2-9)×10-4/h.Signal generators can work at continous wave and square modulated states.
On the basis of the principle of "electronically tuning fundamental frequency and extracting second harmonic",this paper proposes a circuit model for wideband series varactor tuned harmonic oscillators.At W-band electronic tuned bandwidth of 15% is achieved within which the minimum power is 5 mW and the maximum over 17 mW.Electronic tuned bandwidth of 13 GHz over 5 mW is obtained.Applying these oscillators,this paper develops electronically tuning signal generators at W-band.Operating bandwidth of signal generators is 10 GHz,frequency error less than 100 MHz,frequency stability (2-9)×10-4/h.Signal generators can work at continous wave and square modulated states.
1997, 26(2): 148-151.
Abstract:
An E-plane suspended dielectric resonator structure specially suitable for millimeter wave is suggested in this paper,which is compatible with E-plane integrated circuits and can achieve much higher Q-factor than those of microstrip structure.This structure provides an approach for high Q-factor elements which could enlarge the application field of E-plane integrated circuits and improve their performance.A Ka and band E-plane suspended dielectric resonator is analyzed and tested,which achieves Q-factor over 3 000.
An E-plane suspended dielectric resonator structure specially suitable for millimeter wave is suggested in this paper,which is compatible with E-plane integrated circuits and can achieve much higher Q-factor than those of microstrip structure.This structure provides an approach for high Q-factor elements which could enlarge the application field of E-plane integrated circuits and improve their performance.A Ka and band E-plane suspended dielectric resonator is analyzed and tested,which achieves Q-factor over 3 000.
1997, 26(2): 152-156.
Abstract:
The high speed insulated gate bipolar transistor(IGBT) transport model is derived by ambipolar transport theory in this paper.In the steady state,it opreates as the common IGBT;but in the transient state,it's turm-off time is much smaller than the common IGBT because of the extraction of non-equilibrium carriers in the base region caused by N+ anode.In this paper the steady and transient state characteristics of the high speed IGBT are analyzed by the use of two-dimension device numerical simulator(PISCES ⅡB).The insight physical parameters such as the concertration distribution,current prfiles,and the trun-off time(Toff) are acquired.Simulation results are in agreement with the experiments.
The high speed insulated gate bipolar transistor(IGBT) transport model is derived by ambipolar transport theory in this paper.In the steady state,it opreates as the common IGBT;but in the transient state,it's turm-off time is much smaller than the common IGBT because of the extraction of non-equilibrium carriers in the base region caused by N+ anode.In this paper the steady and transient state characteristics of the high speed IGBT are analyzed by the use of two-dimension device numerical simulator(PISCES ⅡB).The insight physical parameters such as the concertration distribution,current prfiles,and the trun-off time(Toff) are acquired.Simulation results are in agreement with the experiments.
1997, 26(2): 157-161.
Abstract:
The Y-circulator consisted of a unilateral fin -line Y-junction with three impedance transformers and a ferite disk as magnetically active element is discribed in this paper,which suits well for integrated system.An fin-line circulator with a low insertion loss and a high isolation at Ka band is developed.
The Y-circulator consisted of a unilateral fin -line Y-junction with three impedance transformers and a ferite disk as magnetically active element is discribed in this paper,which suits well for integrated system.An fin-line circulator with a low insertion loss and a high isolation at Ka band is developed.
1997, 26(2): 162-166.
Abstract:
The estimated service life of optic disks at the normal temperature is 20 years by use of the acceleration experiment and Arrhenius figure.The specific properties of mechanics and record of optic disks is tested through environment experiment.The test results indicate that some of the experiments lightly influenced the specific properties of mechanics,the others triflingly affect that of record,such as the reflection rate of recording layer,BER,etc.The way of improving the reliability of megneto-optic disk is raised preliminarily by analyzing the specific properties,the stale mechanism of the base of megnesto optic recording layers and the protective layer.
The estimated service life of optic disks at the normal temperature is 20 years by use of the acceleration experiment and Arrhenius figure.The specific properties of mechanics and record of optic disks is tested through environment experiment.The test results indicate that some of the experiments lightly influenced the specific properties of mechanics,the others triflingly affect that of record,such as the reflection rate of recording layer,BER,etc.The way of improving the reliability of megneto-optic disk is raised preliminarily by analyzing the specific properties,the stale mechanism of the base of megnesto optic recording layers and the protective layer.
1997, 26(2): 167-170.
Abstract:
Calculation of double carry control,a cyclic control for both time sample and state variable is presented.The nonlinearity in a special bilinear system is simplified to a linear system which could be solved exactly.The rotation operator is introduced to manifest the change of proportional variable structure.The combination control of mode change in variable structure and digit simulation is expressed.The structure diagram for the control design is shown.
Calculation of double carry control,a cyclic control for both time sample and state variable is presented.The nonlinearity in a special bilinear system is simplified to a linear system which could be solved exactly.The rotation operator is introduced to manifest the change of proportional variable structure.The combination control of mode change in variable structure and digit simulation is expressed.The structure diagram for the control design is shown.
1997, 26(2): 171-174.
Abstract:
This paper presents a testability optimization method based on free binary decision diagram transformation.In this method,circuit is first converted to FBDD representation,then converted to easily testable multi-level network by replacing BDD nodes with multiplexors,and finally converted to testable circuit by redundancy removal.The method's advantage over the classical ones is that it is suitable for almost arbitrary circuits,especially very large scale circuits that can not be represented by two-level logic.
This paper presents a testability optimization method based on free binary decision diagram transformation.In this method,circuit is first converted to FBDD representation,then converted to easily testable multi-level network by replacing BDD nodes with multiplexors,and finally converted to testable circuit by redundancy removal.The method's advantage over the classical ones is that it is suitable for almost arbitrary circuits,especially very large scale circuits that can not be represented by two-level logic.
1997, 26(2): 175-179.
Abstract:
A distributed transaction processing model and its realizing protocol based on RPC are proposed for client/server applications in current network environment.Analysis and experiment show that it not only satisfies specific properties and requirements of client/server application,but also overcomes the blocking in the two phase commit protocol caused by coordinator breakdowns,and avoids shortcomings of more expenses and difficult to realize in three phase commit protocol.
A distributed transaction processing model and its realizing protocol based on RPC are proposed for client/server applications in current network environment.Analysis and experiment show that it not only satisfies specific properties and requirements of client/server application,but also overcomes the blocking in the two phase commit protocol caused by coordinator breakdowns,and avoids shortcomings of more expenses and difficult to realize in three phase commit protocol.
1997, 26(2): 180-184.
Abstract:
A microcomputer-based limited-handwritten chinese character recognition method is proposed in this paper.The simulation test is built on the basis of a 486 DX/66 microcomputer.The method is to be put into effort.The proposed algorithms for preprocessing of limited-hand-written chinese character is a method combining strctural pattern recognition and statistical pattern recognition and fuzzy mathematics.A recognition method about analog chinese character is proposed in this paper.
A microcomputer-based limited-handwritten chinese character recognition method is proposed in this paper.The simulation test is built on the basis of a 486 DX/66 microcomputer.The method is to be put into effort.The proposed algorithms for preprocessing of limited-hand-written chinese character is a method combining strctural pattern recognition and statistical pattern recognition and fuzzy mathematics.A recognition method about analog chinese character is proposed in this paper.
1997, 26(2): 185-189.
Abstract:
It is very difficult to debug distributed program because of the nondetermiantion of distributed program execution.So,it is almost impossible to debug distributed program with traditional tools.CASE -DDB is an event -based debugger for debugging distributed program written in distributed C++.This paper introduces its rationale and realization,and provides a method to debug nondeterminative distributed program.
It is very difficult to debug distributed program because of the nondetermiantion of distributed program execution.So,it is almost impossible to debug distributed program with traditional tools.CASE -DDB is an event -based debugger for debugging distributed program written in distributed C++.This paper introduces its rationale and realization,and provides a method to debug nondeterminative distributed program.
1997, 26(2): 190-193.
Abstract:
Security is a very important aspect in network.Authentication is fundamental in maintaining security in the nework.Authentication is a process that satisfies another about one's claim of identity,which quality affects the security and performance of the system.Many activities cannot proceed without authentication because its compromise can lead to the compromise of the whole system.Therefore,a desirable authentication serices should be both highly reliable and secure.A threshold-based authentication service is presented in this paper,and reliability and security of the service are analyzed.Adjusting the thresholds can explore the tradeoff between reliability and security.
Security is a very important aspect in network.Authentication is fundamental in maintaining security in the nework.Authentication is a process that satisfies another about one's claim of identity,which quality affects the security and performance of the system.Many activities cannot proceed without authentication because its compromise can lead to the compromise of the whole system.Therefore,a desirable authentication serices should be both highly reliable and secure.A threshold-based authentication service is presented in this paper,and reliability and security of the service are analyzed.Adjusting the thresholds can explore the tradeoff between reliability and security.
1997, 26(2): 194-198.
Abstract:
In this paper,the problem of maximizing monopoly revenue under the condition that the second degree price discrimination is allowed,is studied.The maximum condtion of monopoly revenue and the maximum revenue a monopolist may earn are given.The relevant computing formulas are very simple and the process of maximing the monopoly revenue is easy to carry out.Some new results presented in this paper are of importonce to both firms and consumers.
In this paper,the problem of maximizing monopoly revenue under the condition that the second degree price discrimination is allowed,is studied.The maximum condtion of monopoly revenue and the maximum revenue a monopolist may earn are given.The relevant computing formulas are very simple and the process of maximing the monopoly revenue is easy to carry out.Some new results presented in this paper are of importonce to both firms and consumers.
1997, 26(2): 199-203.
Abstract:
A delay differential inequality,which is of impartance to the research for the stability of delay system,was established in Ref. by A.Halanay.However,as far as the stability of Neutral system is concerned,Halanay's inequality is hard to apply.This paper generalizes the delay differential inequality and establishes a delay integral inequality.Applying this inequality to study the neutral differential equations,some simple sufficient criteria are obtained for judging global exponential stability.
A delay differential inequality,which is of impartance to the research for the stability of delay system,was established in Ref. by A.Halanay.However,as far as the stability of Neutral system is concerned,Halanay's inequality is hard to apply.This paper generalizes the delay differential inequality and establishes a delay integral inequality.Applying this inequality to study the neutral differential equations,some simple sufficient criteria are obtained for judging global exponential stability.
1997, 26(2): 204-207.
Abstract:
Ref.[1] discussed the random variables sequence {xi}'s complete convergent rates when its variable suits certain conditions in Banach space.In this paper,the convergent rates of the random variables sequence when its variable is independent and mixed each other in Banach space are discussed.While the variable sequence {xi} consists of the real random variable,the result satisfies the Theory 1 in Ref[1].At last,some results are abtained.
Ref.[1] discussed the random variables sequence {xi}'s complete convergent rates when its variable suits certain conditions in Banach space.In this paper,the convergent rates of the random variables sequence when its variable is independent and mixed each other in Banach space are discussed.While the variable sequence {xi} consists of the real random variable,the result satisfies the Theory 1 in Ref[1].At last,some results are abtained.
1997, 26(2): 208-214.
Abstract:
Locus of mation for particle in the field of inhomogeneous plane wave will be elliptic when the homogeneous plane wave incidents upon the interface of liquid -thermoviscoelastic and generates the inhomogeneous plane waves.Calculations show:for the particles which are located in the fields of longitudinal and transversal wave,the ellipticity will be 1 if the incidence is much smaller than their critical angle;the ellipticity will be the smallest if the incidence is much bigger than their critical angles;the ellipticity will change much if the incidence is near their critical angles.For the particles which are located in the field of entropic or reflective wave,the ellipticity of the former will diminish linearly approximately versus angle of incidence;the ellipticity of the latter is totally 1.The ellipticity will change periodically versus depth of interface under the incidence of Rayleigh angle.The ellipticity will be 1 if the depths are the integer times of wavelength of Rayleigh wave and the ellipticity will be the smallest if the depths are the odd times of half wavelength of Rayleigh wave.
Locus of mation for particle in the field of inhomogeneous plane wave will be elliptic when the homogeneous plane wave incidents upon the interface of liquid -thermoviscoelastic and generates the inhomogeneous plane waves.Calculations show:for the particles which are located in the fields of longitudinal and transversal wave,the ellipticity will be 1 if the incidence is much smaller than their critical angle;the ellipticity will be the smallest if the incidence is much bigger than their critical angles;the ellipticity will change much if the incidence is near their critical angles.For the particles which are located in the field of entropic or reflective wave,the ellipticity of the former will diminish linearly approximately versus angle of incidence;the ellipticity of the latter is totally 1.The ellipticity will change periodically versus depth of interface under the incidence of Rayleigh angle.The ellipticity will be 1 if the depths are the integer times of wavelength of Rayleigh wave and the ellipticity will be the smallest if the depths are the odd times of half wavelength of Rayleigh wave.
1997, 26(2): 215-220.
Abstract:
Electrohydrodimerization (EHD) of fumarodinitrile (FDN)on Gallium takes place not only from hydrotropic solutions of tetraethylammonium p toluenesulphonate (TEA PTS),but also from entrirely aqueous solution containing very low concentrations (say 10-1~10-3 mol·L-1) of strong surfactants,such as TritonX 100.In aqueous solution,not containing organic surfactants,FDN yields a single two electron reduction wave to the corresponding saturated (RH 2).Progressive additions of surfactants,the original two electron wave is splitted into two consecutire single electron reduction wave and the EHD of fumarodinitrile is obtained.
Electrohydrodimerization (EHD) of fumarodinitrile (FDN)on Gallium takes place not only from hydrotropic solutions of tetraethylammonium p toluenesulphonate (TEA PTS),but also from entrirely aqueous solution containing very low concentrations (say 10-1~10-3 mol·L-1) of strong surfactants,such as TritonX 100.In aqueous solution,not containing organic surfactants,FDN yields a single two electron reduction wave to the corresponding saturated (RH 2).Progressive additions of surfactants,the original two electron wave is splitted into two consecutire single electron reduction wave and the EHD of fumarodinitrile is obtained.
1997, 26(2): 220-224.
Abstract:
Several working modes of the synchronous AC/DC converters are introduced in this paper.The synchronous converters are composed of two main parts:DC componant generation and DC power extraction.The basic working modes are 50 Hz single peak waves,100 Hz SPW and 50 Hz double peak waves.The realized circutis working in those modes are proposed.The external characteristics of those circuits are compared and examed.Experimental results are also provided.
Several working modes of the synchronous AC/DC converters are introduced in this paper.The synchronous converters are composed of two main parts:DC componant generation and DC power extraction.The basic working modes are 50 Hz single peak waves,100 Hz SPW and 50 Hz double peak waves.The realized circutis working in those modes are proposed.The external characteristics of those circuits are compared and examed.Experimental results are also provided.
