ISSN 
1998 Vol. 27, No. 2
1998, 27(2): 113-117.
Abstract:
This paper introduces a new media access protocol for high-speed packet switched multichannel networks,and analyzes the properties of time delay(request delay and data delay) and through-put(considering collision) by mathematical method and computer simulation.The reasults are all mean value under the nonreal time service.
This paper introduces a new media access protocol for high-speed packet switched multichannel networks,and analyzes the properties of time delay(request delay and data delay) and through-put(considering collision) by mathematical method and computer simulation.The reasults are all mean value under the nonreal time service.
1998, 27(2): 118-122.
Abstract:
Orthogonal frequency division multiplexing (OFDM) is a general technique for data paralled transmission on multiple carriers.One principal advantage of OFDM is its utility for transmission at nearly optimum performance in unequalized channels and in multipath channesl.OFDM-CDMA is a new concept that applies the orthogonal multicarrier technique to direct sequence CDMA systems.A synchronous OFDM-CDMA model is presented in this paper,and the performance of this system in a non selective Rician fading channel is also evaluated.The numerical results show the system bit error probability degrades rapidly due to multipath component.
Orthogonal frequency division multiplexing (OFDM) is a general technique for data paralled transmission on multiple carriers.One principal advantage of OFDM is its utility for transmission at nearly optimum performance in unequalized channels and in multipath channesl.OFDM-CDMA is a new concept that applies the orthogonal multicarrier technique to direct sequence CDMA systems.A synchronous OFDM-CDMA model is presented in this paper,and the performance of this system in a non selective Rician fading channel is also evaluated.The numerical results show the system bit error probability degrades rapidly due to multipath component.
1998, 27(2): 123-128.
Abstract:
In this paper,the application of adaptive technique for narrow-band suppression in spread-spectrum (SS) communication is discussed and its numerical robustness is analyzed.In order to increase the converge rate and improve the output signal noise ratio,a combined filter mode is proposed and a new combinde adaptive filter is constructed based on a interpolator filter.Finally,the interference suppression ability of both basic adaptive filters and its combined counterparts is compared in theory and in practice.
In this paper,the application of adaptive technique for narrow-band suppression in spread-spectrum (SS) communication is discussed and its numerical robustness is analyzed.In order to increase the converge rate and improve the output signal noise ratio,a combined filter mode is proposed and a new combinde adaptive filter is constructed based on a interpolator filter.Finally,the interference suppression ability of both basic adaptive filters and its combined counterparts is compared in theory and in practice.
1998, 27(2): 129-135.
Abstract:
In this paper,the reflection characteristics of a plane wave of TE-polarization incidented with large incident angle on the surface of a multilayer structural absorber without metal base is investigated in detail.A generalized matrix formula is derived to connect the EM fields in adjacent layers.The reflection coefficients of two and three layer absorbers are evaluated.The conditions under which the low reflectances may be achieved are investigated.Based on these analysis,an easy handled design method is presented.Design examples of two and three layer structural absorbers for inlet and absorbing-quide plate in inlet all give good performances.
In this paper,the reflection characteristics of a plane wave of TE-polarization incidented with large incident angle on the surface of a multilayer structural absorber without metal base is investigated in detail.A generalized matrix formula is derived to connect the EM fields in adjacent layers.The reflection coefficients of two and three layer absorbers are evaluated.The conditions under which the low reflectances may be achieved are investigated.Based on these analysis,an easy handled design method is presented.Design examples of two and three layer structural absorbers for inlet and absorbing-quide plate in inlet all give good performances.
1998, 27(2): 136-139.
Abstract:
How to apply the circuit analog to radar structural absorbers to improve their reflection characteristics under TE polarization plane wave incidence is studied.The input impedance in the absorber can be increased rapidly by inserting an inductive screen into the absorber.The method to select the screen parameters is given.A design example is presented,which exhibits better performances than those of ordinary design.
How to apply the circuit analog to radar structural absorbers to improve their reflection characteristics under TE polarization plane wave incidence is studied.The input impedance in the absorber can be increased rapidly by inserting an inductive screen into the absorber.The method to select the screen parameters is given.A design example is presented,which exhibits better performances than those of ordinary design.
1998, 27(2): 140-143.
Abstract:
The method of determination of Al2O3 in cement from phospho cypsum by flow injection analysis is developed by means of melting samples by microwave oven and using CAS as chromogenic reagent and Vc as interference free reagent for Fe3+.The interference of Fe- can be eliminated by means of calibration curves.The amounts of Al2O3 are detected in the range of 0~1.2×10-3 g·L-1 with RSD 3.1%,recovery rate 95%~105% and the detection rate 100 sumples·h-1.
The method of determination of Al2O3 in cement from phospho cypsum by flow injection analysis is developed by means of melting samples by microwave oven and using CAS as chromogenic reagent and Vc as interference free reagent for Fe3+.The interference of Fe- can be eliminated by means of calibration curves.The amounts of Al2O3 are detected in the range of 0~1.2×10-3 g·L-1 with RSD 3.1%,recovery rate 95%~105% and the detection rate 100 sumples·h-1.
1998, 27(2): 144-147.
Abstract:
Based on the view point of CAD/CAPP/CAM product information integration and the method of azimcethal characteristic dilinearation,this paper focus on the study and application on the information model foundation of non gyrorotor components,especially of the box comeponents.It results in the orientation of a standard.DXF graphic file,which can be used by other CAD/CAM softwares.This paper also shows geometry,topology,feature,dimension and tolerance models of products in data exchange STEP standard.
Based on the view point of CAD/CAPP/CAM product information integration and the method of azimcethal characteristic dilinearation,this paper focus on the study and application on the information model foundation of non gyrorotor components,especially of the box comeponents.It results in the orientation of a standard.DXF graphic file,which can be used by other CAD/CAM softwares.This paper also shows geometry,topology,feature,dimension and tolerance models of products in data exchange STEP standard.
1998, 27(2): 148-150.
Abstract:
Based on single chip microcomputers,an automatic monitoring system for overall detection of the operating conditions of diesel engine is presented.The system can be used to measure rotational speed of the engine,temperature and pressure of lubricating grease,temperature of cooling water,etc.Furthermore,by data analyzing,the system can give warning if any overrun occurs and stop the engine if runaway phenomenon exists.The measuring principles are discussed in detailed,and the corresponding circuits and block diagram of the system are given in this paper.
Based on single chip microcomputers,an automatic monitoring system for overall detection of the operating conditions of diesel engine is presented.The system can be used to measure rotational speed of the engine,temperature and pressure of lubricating grease,temperature of cooling water,etc.Furthermore,by data analyzing,the system can give warning if any overrun occurs and stop the engine if runaway phenomenon exists.The measuring principles are discussed in detailed,and the corresponding circuits and block diagram of the system are given in this paper.
1998, 27(2): 151-155.
Abstract:
This paper studies the CAT (computer-aided testing)technique with supper computer used in on-line high-precision measurement and data processing system for spindle rotation accuracy.The system consists of maset-ball,general-purpose instruments,supper computer and a set of software's for data processing.Based on eccentricity elimination by digital filter,data processing and error evaluation are discussed.The system is applied in the study of the spindle rotation accuracy of a matching tools' axs.The results of the rotation error are given.
This paper studies the CAT (computer-aided testing)technique with supper computer used in on-line high-precision measurement and data processing system for spindle rotation accuracy.The system consists of maset-ball,general-purpose instruments,supper computer and a set of software's for data processing.Based on eccentricity elimination by digital filter,data processing and error evaluation are discussed.The system is applied in the study of the spindle rotation accuracy of a matching tools' axs.The results of the rotation error are given.
1998, 27(2): 156-160.
Abstract:
In this paper,a novel robost self-tuning algorithm is developed for minimum and nonminimum phase system in the presence of unmodeled dynamics and external disturbances by means of the project estimation with mapping modification.The robust stability of the proposed algorithm is proved.Otherwise,the relationship between the unmodeled dynamics and the variance of the predicted error is characterized.Both theoretical analysis and simulation study show the effectiveness of the method.
In this paper,a novel robost self-tuning algorithm is developed for minimum and nonminimum phase system in the presence of unmodeled dynamics and external disturbances by means of the project estimation with mapping modification.The robust stability of the proposed algorithm is proved.Otherwise,the relationship between the unmodeled dynamics and the variance of the predicted error is characterized.Both theoretical analysis and simulation study show the effectiveness of the method.
1998, 27(2): 161-165.
Abstract:
The knowledge presentation of the combination of the AND/OR tree and production rule is applied in the expert system. A knowledge acquisition and diagnosis method based on the bus observation are described in this paper. The analysis of the testability of the bus information and the relativity of the fault information is given, which provides the validity criterion for the diagnosis method based on the bus observation. The test results demonstrate that the expert system is quite good in the inference efficiency and diagnostic resolution.
The knowledge presentation of the combination of the AND/OR tree and production rule is applied in the expert system. A knowledge acquisition and diagnosis method based on the bus observation are described in this paper. The analysis of the testability of the bus information and the relativity of the fault information is given, which provides the validity criterion for the diagnosis method based on the bus observation. The test results demonstrate that the expert system is quite good in the inference efficiency and diagnostic resolution.
1998, 27(2): 166-170.
Abstract:
The influence of large coupler on the cavity paramters of relativistic klystron amplifier is described in this paper.The parameters include the plots of electron field,resonance frequency, Q value,characteristic impetance,and coefficience of coupler.A new coupling structure is designed to resolve the influence,especially the resonance frequency,coupling coeficience and the plots of eletron field.The results is very important for the device design of high power microwave.
The influence of large coupler on the cavity paramters of relativistic klystron amplifier is described in this paper.The parameters include the plots of electron field,resonance frequency, Q value,characteristic impetance,and coefficience of coupler.A new coupling structure is designed to resolve the influence,especially the resonance frequency,coupling coeficience and the plots of eletron field.The results is very important for the device design of high power microwave.
1998, 27(2): 171-176.
Abstract:
The rigorous theoretical formula to calculate the first and second kinds of arbitrary real order Bessel functions with complex argument is derived by means of the series expansion in this paper.The modified Bessel functions of the first and second kind with complex argument can also be calculated by these formula.The discrepancy of the numerical results obtained in this paper is compared to those given by the mathematica software package.
The rigorous theoretical formula to calculate the first and second kinds of arbitrary real order Bessel functions with complex argument is derived by means of the series expansion in this paper.The modified Bessel functions of the first and second kind with complex argument can also be calculated by these formula.The discrepancy of the numerical results obtained in this paper is compared to those given by the mathematica software package.
1998, 27(2): 177-180.
Abstract:
In this paper,the idea of the design of the multimedia CAI software for CPU is presented,and the method of developing software is disscussed by means of Authorware and Visaul Basic for Window.It solves the problems in application such as the conjunction between the programs which are developed by different tools,the implemenetation of the hyper media technology and so on.
In this paper,the idea of the design of the multimedia CAI software for CPU is presented,and the method of developing software is disscussed by means of Authorware and Visaul Basic for Window.It solves the problems in application such as the conjunction between the programs which are developed by different tools,the implemenetation of the hyper media technology and so on.
1998, 27(2): 181-184.
Abstract:
This paper combines the technology of computer and charge coupling device (CCD) and applies it in the millikon oildrops experiment by the use of CCD linear matrix.It also provides a new noncontacted methdo of linear length survery for college physics experiments and modern industrial automatical production system,and displays the great vitality and vast vistas of CCD technology for physics experiments.
This paper combines the technology of computer and charge coupling device (CCD) and applies it in the millikon oildrops experiment by the use of CCD linear matrix.It also provides a new noncontacted methdo of linear length survery for college physics experiments and modern industrial automatical production system,and displays the great vitality and vast vistas of CCD technology for physics experiments.
1998, 27(2): 185-189.
Abstract:
A new efficiency theory of multiple criteria decision making is established in this paper.The new effciency is based on the differences among weights of the criteria,with "the larger the weight sum of the better criteria is,the better the related alternative" being the preference principle.The key definitions in this paper are β-major-in-weight efficient solution and β-major-in-weight optimal solution.Some properties of these solutions are shown.The relationships between them and Pareto efficient (optimal) solution are discussed.
A new efficiency theory of multiple criteria decision making is established in this paper.The new effciency is based on the differences among weights of the criteria,with "the larger the weight sum of the better criteria is,the better the related alternative" being the preference principle.The key definitions in this paper are β-major-in-weight efficient solution and β-major-in-weight optimal solution.Some properties of these solutions are shown.The relationships between them and Pareto efficient (optimal) solution are discussed.
1998, 27(2): 190-193.
Abstract:
Direct recognition of the redundant methods of optimal combining forecasts with non-negative weights from information matrix or covariance matrix of forecasting errors can simplify the computation of optimal weights and therefore help the practical application of optimal combination forecasting.In this paper,a supplement to the criteria for determining the redundant methods is proposed and illustrated to be more applicable than the previous criteria.Furthermore,the limitations in the present study of combining forecasts with non negative weights and redundant methods are discussed and further research of robust combining forecasts with non-negative weights,which is adaptable to structural changes is proposed.
Direct recognition of the redundant methods of optimal combining forecasts with non-negative weights from information matrix or covariance matrix of forecasting errors can simplify the computation of optimal weights and therefore help the practical application of optimal combination forecasting.In this paper,a supplement to the criteria for determining the redundant methods is proposed and illustrated to be more applicable than the previous criteria.Furthermore,the limitations in the present study of combining forecasts with non negative weights and redundant methods are discussed and further research of robust combining forecasts with non-negative weights,which is adaptable to structural changes is proposed.
1998, 27(2): 194-198.
Abstract:
Economic theory of regulation is applied to analyze the objective of pricing and regulation,the formation of electricity price and the system of electricity price in this paper.The model of peak load rate is developed,which is the theoretial foundation of "peak-botton variable rates".The study is of importance for the pricing and regulation in Chinese electricity industry and for the current reform of electricity.
Economic theory of regulation is applied to analyze the objective of pricing and regulation,the formation of electricity price and the system of electricity price in this paper.The model of peak load rate is developed,which is the theoretial foundation of "peak-botton variable rates".The study is of importance for the pricing and regulation in Chinese electricity industry and for the current reform of electricity.
1998, 27(2): 199-203.
Abstract:
This paper gives an optimal algorithm for balancing system reliability and cost on fuzzy sets.It is more effective to help make a decision when the goals (system reliability) and/or constraints (cost) are fuzzy.It is different from normal algorithm which is more flexible and reasonable.
This paper gives an optimal algorithm for balancing system reliability and cost on fuzzy sets.It is more effective to help make a decision when the goals (system reliability) and/or constraints (cost) are fuzzy.It is different from normal algorithm which is more flexible and reasonable.
1998, 27(2): 204-208.
Abstract:
In this paper,noninferior nature of the solution of multiobjective dynamic programming is discussed.Three concepts are given,which are multiobjective return noninferior matrix,multiobjective return noninferior compound matrix and multiobjective forward recurrence matrix.On the basis of the three concepts,a new method of noninferior matrix of multiobjective dynamic programming is given.In the method,the relative importance of the whole objectives may not be given beforehand,and all the noninferior solutions can be gotten easily.The validity of the method is tested and verified by an example.
In this paper,noninferior nature of the solution of multiobjective dynamic programming is discussed.Three concepts are given,which are multiobjective return noninferior matrix,multiobjective return noninferior compound matrix and multiobjective forward recurrence matrix.On the basis of the three concepts,a new method of noninferior matrix of multiobjective dynamic programming is given.In the method,the relative importance of the whole objectives may not be given beforehand,and all the noninferior solutions can be gotten easily.The validity of the method is tested and verified by an example.
1998, 27(2): 209-215.
Abstract:
This paper studies the existence of periodic solutions of neutral differential equations with infinite delay and delay equations of nth order.Some necessary and sufficient conditions for existence of periodic solutions are obtained via the thoery of Fourier series.
This paper studies the existence of periodic solutions of neutral differential equations with infinite delay and delay equations of nth order.Some necessary and sufficient conditions for existence of periodic solutions are obtained via the thoery of Fourier series.
1998, 27(2): 216-218.
Abstract:
Both (Block) H-matrices and sub-positive definite matrices are the important matrices classes in numerical mathematics and matrix theory,which are applicable in many fields.In this paper,the intership is studied between the two matrices.The new results obtained are interesting in theory and practice.
Both (Block) H-matrices and sub-positive definite matrices are the important matrices classes in numerical mathematics and matrix theory,which are applicable in many fields.In this paper,the intership is studied between the two matrices.The new results obtained are interesting in theory and practice.
1998, 27(2): 219-224.
Abstract:
Adaptive method and variable scale method are introduced in this paper.Two sorts of optimal method are applied to optical system design by means of program developed of C Language.Two sorts of typical optical system are designed.Based on the overall analysis and contrast of the speed,stability,convenience of design etc,the result and the process demonstate that the variable scale method is a better optimal algorithm in optical design.
Adaptive method and variable scale method are introduced in this paper.Two sorts of optimal method are applied to optical system design by means of program developed of C Language.Two sorts of typical optical system are designed.Based on the overall analysis and contrast of the speed,stability,convenience of design etc,the result and the process demonstate that the variable scale method is a better optimal algorithm in optical design.
