ISSN 
1999 Vol. 28, No. 3
1999, 28(3): 223-227.
Abstract:
It is proved in this paper that the periodic extension matches the structure of Daub filter better than the symmetric extension when using the filter in wavelet image coding. Then, the statistical property of wavelet coefficients and runlength probability are analyzed. Finally high compression ratio and high signal-to-noise ratio in image coding are achieved based on above analysis.
It is proved in this paper that the periodic extension matches the structure of Daub filter better than the symmetric extension when using the filter in wavelet image coding. Then, the statistical property of wavelet coefficients and runlength probability are analyzed. Finally high compression ratio and high signal-to-noise ratio in image coding are achieved based on above analysis.
1999, 28(3): 228-232.
Abstract:
According to the dynamic features of NGSO MSS networks,this paper puts forward a hybrid channel assignment scheme.In the scheme,fixed channels are allocated to cells for exclusive use as nominal channels and reallocated after periodic time in terms of time-variant traffic distribution using ununiform compact pattern allocation algorithm. Available algorithm is used to assign dynamic channels.Computer simulation results show that the HCA scheme has better performance compared with FCA scheme and can effectively reduce handover failure and call disruption rates on channel updating times,thus greatly improve network traffic-carrying capacity.
According to the dynamic features of NGSO MSS networks,this paper puts forward a hybrid channel assignment scheme.In the scheme,fixed channels are allocated to cells for exclusive use as nominal channels and reallocated after periodic time in terms of time-variant traffic distribution using ununiform compact pattern allocation algorithm. Available algorithm is used to assign dynamic channels.Computer simulation results show that the HCA scheme has better performance compared with FCA scheme and can effectively reduce handover failure and call disruption rates on channel updating times,thus greatly improve network traffic-carrying capacity.
1999, 28(3): 233-237.
Abstract:
PRMA with multiple voice priority is investigated in this paper Analytical model is conducted and computer simulation is carried out, and equilibrium points analysis (EPA) method is used for its performance evaluation. The analytical and simulation results indicate that the PRMA can support the VBR voice traffic and low-bit-rate VBR data traffic. It is shown that if the number of high priority voice terminals exceeds a threshold, the PPRMA system will be blocked.
PRMA with multiple voice priority is investigated in this paper Analytical model is conducted and computer simulation is carried out, and equilibrium points analysis (EPA) method is used for its performance evaluation. The analytical and simulation results indicate that the PRMA can support the VBR voice traffic and low-bit-rate VBR data traffic. It is shown that if the number of high priority voice terminals exceeds a threshold, the PPRMA system will be blocked.
1999, 28(3): 238-242.
Abstract:
The multicarrier CDMA (MC-CDMA) is a novel digital modulation and multiplexing technique. Its performance is limited by multi-access interference (MAI). The optimum detector for MC-CDMA is based on the maximum likelihood sequence estimation (MLSE). However its complexity increases exponentially with the number of the users. To reduce its computational complexity, a near optimum MC-CDMA detector based on Greedy Algorithm (GA) is studied. The obtained results show considerable performance improvement compared to the conventional MC-CDMA detector and low computation complexity compared to the optimum detector.
The multicarrier CDMA (MC-CDMA) is a novel digital modulation and multiplexing technique. Its performance is limited by multi-access interference (MAI). The optimum detector for MC-CDMA is based on the maximum likelihood sequence estimation (MLSE). However its complexity increases exponentially with the number of the users. To reduce its computational complexity, a near optimum MC-CDMA detector based on Greedy Algorithm (GA) is studied. The obtained results show considerable performance improvement compared to the conventional MC-CDMA detector and low computation complexity compared to the optimum detector.
1999, 28(3): 243-246.
Abstract:
A signal processing system of 3mm-wave pulse radars for RPVs is accomplished with DSP chip PDSP16510 and PLD Flex10k. The method of suppressing the main lobe clutter of airborne Pulse radars in video signal processing system is proposed to deal with the problem generally existing in airborne radars. The system has the advantages of high processing speed high range and spectrum resolution and easily programmable control. It also has the features of light weight small volume and high reliability. The measuring results are also given in this paper.
A signal processing system of 3mm-wave pulse radars for RPVs is accomplished with DSP chip PDSP16510 and PLD Flex10k. The method of suppressing the main lobe clutter of airborne Pulse radars in video signal processing system is proposed to deal with the problem generally existing in airborne radars. The system has the advantages of high processing speed high range and spectrum resolution and easily programmable control. It also has the features of light weight small volume and high reliability. The measuring results are also given in this paper.
1999, 28(3): 247-250.
Abstract:
In this paper, the maximum-likelihood detection and its performance are studied for the sampled signal in all digital receivers of optical PPM communications. The algorithm of demodulation and its upper bound of error probability are given for any pulse shape received. Especially, the suboptimum decision algorithm of maximum accumulate count is discussed with a view of easy implementation. The effects of various factors are investigated. These results are helpful to designing all digital PPM receivers.
In this paper, the maximum-likelihood detection and its performance are studied for the sampled signal in all digital receivers of optical PPM communications. The algorithm of demodulation and its upper bound of error probability are given for any pulse shape received. Especially, the suboptimum decision algorithm of maximum accumulate count is discussed with a view of easy implementation. The effects of various factors are investigated. These results are helpful to designing all digital PPM receivers.
1999, 28(3): 251-254.
Abstract:
A new millimeter-wave E-plane hybrid integrated electronically tuning oscillator using beam lead varactor is presented, and it's designing method is also introduced in this paper By combining E-plane suspend coupled strip with finline transmission line, this oscillator working at 35 GHz has 780 MHz electronically tuning bandwidth and 19.3±0.5 dBm power at the output waveguide port.
A new millimeter-wave E-plane hybrid integrated electronically tuning oscillator using beam lead varactor is presented, and it's designing method is also introduced in this paper By combining E-plane suspend coupled strip with finline transmission line, this oscillator working at 35 GHz has 780 MHz electronically tuning bandwidth and 19.3±0.5 dBm power at the output waveguide port.
1999, 28(3): 255-258.
Abstract:
A new Multigrid-FFT (MGFFT) algorithm, combined multigrid method with FFT, is presented in this paper for analyzing scattering from electrically large structures. Used as an efficient iterative algorithm, multigrid method (MG) is different from other multilevel MoM in nature. In the MG procedure, the FFT is applied for the calculation of the convolutional integrals involved. The numerical results shown that the MGFFT method is an efficient approach for the analysis of electrically ladle size problems.
A new Multigrid-FFT (MGFFT) algorithm, combined multigrid method with FFT, is presented in this paper for analyzing scattering from electrically large structures. Used as an efficient iterative algorithm, multigrid method (MG) is different from other multilevel MoM in nature. In the MG procedure, the FFT is applied for the calculation of the convolutional integrals involved. The numerical results shown that the MGFFT method is an efficient approach for the analysis of electrically ladle size problems.
1999, 28(3): 259-261.
Abstract:
The principle of deep trench termination for improving the avalanche breakdown of thedevice is studied. The effects of trench's depth and width, the field plate, the dielectric used to fill trench onthe avalanche breakdown voltage are analyzed using MEDICI. The results indicate that deep trenchtermination with field plate increases avalanche breakdown voltage of that of the device to 90% of that ofthe parallel plane junction. Meanwhile, the structure helps increase the cut-off frequency, the dissipationpower and the device reliability by decreasing the actual junction area and the surface leaking current.
The principle of deep trench termination for improving the avalanche breakdown of thedevice is studied. The effects of trench's depth and width, the field plate, the dielectric used to fill trench onthe avalanche breakdown voltage are analyzed using MEDICI. The results indicate that deep trenchtermination with field plate increases avalanche breakdown voltage of that of the device to 90% of that ofthe parallel plane junction. Meanwhile, the structure helps increase the cut-off frequency, the dissipationpower and the device reliability by decreasing the actual junction area and the surface leaking current.
1999, 28(3): 262-265.
Abstract:
When gas turbine works, rotational speed is affected by oil, air and so on, and there are strong cross-coupling between these factors. It is difficult to found an accurate mathematical model for the working process of gas turbine, so, the rotational speed of gas turbine can not be controlled by classical control theory. For the control problem of rotational speed of gas turbine, a useful self-optimizing fuzzy-PI control scheme is presented. According to fuzzy inference synthetize rule, the fuzzy control result is obtained. The fuzzy control result is used to control practical system and has met with success.
When gas turbine works, rotational speed is affected by oil, air and so on, and there are strong cross-coupling between these factors. It is difficult to found an accurate mathematical model for the working process of gas turbine, so, the rotational speed of gas turbine can not be controlled by classical control theory. For the control problem of rotational speed of gas turbine, a useful self-optimizing fuzzy-PI control scheme is presented. According to fuzzy inference synthetize rule, the fuzzy control result is obtained. The fuzzy control result is used to control practical system and has met with success.
1999, 28(3): 266-268.
Abstract:
This paper presents a system which uses the automatic detecting technology to detect and control the surface temperature of the cement rotary kiln. The detecting principle, control method and feature of the system are achieved in this paper This paper also deals with the processing of temperature signal. The structure of the system is simple, it's stability is good, and the system operates well. It can be used to control practical system, which has met with success.
This paper presents a system which uses the automatic detecting technology to detect and control the surface temperature of the cement rotary kiln. The detecting principle, control method and feature of the system are achieved in this paper This paper also deals with the processing of temperature signal. The structure of the system is simple, it's stability is good, and the system operates well. It can be used to control practical system, which has met with success.
1999, 28(3): 269-272.
Abstract:
In this paper, the theoretical analysis and the experiments show that the load spectrum of a machine can be extracted from the output signal by homomorphic signal processing. A method of determining the window width according to the Green function of a time series model is presented as well.So it is easier to choose the width in a limited range. As an example, the torque identification of a shearer drum is described.
In this paper, the theoretical analysis and the experiments show that the load spectrum of a machine can be extracted from the output signal by homomorphic signal processing. A method of determining the window width according to the Green function of a time series model is presented as well.So it is easier to choose the width in a limited range. As an example, the torque identification of a shearer drum is described.
1999, 28(3): 273-277.
Abstract:
A multitaper spectral estimator is built based on the minimization of a cost function. It is indicated by the performance analysis that the approach here has comparative bias and variance as the approach of discrete prolate spheroidal sequence multitaper spectral analysis. Compared with the DPSS,instead of solving the problem of matrix eigenvalues, the multitaper in this paper needs less calculation with intuitionistic and analytical expression of tapers. The validity and the correctness of the approach are verified by the computer emulation of a discrete white noise sequence and an AR progress.
A multitaper spectral estimator is built based on the minimization of a cost function. It is indicated by the performance analysis that the approach here has comparative bias and variance as the approach of discrete prolate spheroidal sequence multitaper spectral analysis. Compared with the DPSS,instead of solving the problem of matrix eigenvalues, the multitaper in this paper needs less calculation with intuitionistic and analytical expression of tapers. The validity and the correctness of the approach are verified by the computer emulation of a discrete white noise sequence and an AR progress.
1999, 28(3): 278-282.
Abstract:
In this paper. two kinds of surrogate data are designed according to electroencephalography (EEG) data. They are a binomial random series with the same source entropy as that of EEG and an AR series that is the output of AR model constructed from EEG data and driven by white noise. Significant differences among the complexity of these three series show that BEG is far from being random and has certain pattern in it which can be partially modeled by AR. The complexity of EEG series recorded during three different mental states is computed and the result of two-way analysis of variance shows that the complexity can discriminate the three mental states significantly.
In this paper. two kinds of surrogate data are designed according to electroencephalography (EEG) data. They are a binomial random series with the same source entropy as that of EEG and an AR series that is the output of AR model constructed from EEG data and driven by white noise. Significant differences among the complexity of these three series show that BEG is far from being random and has certain pattern in it which can be partially modeled by AR. The complexity of EEG series recorded during three different mental states is computed and the result of two-way analysis of variance shows that the complexity can discriminate the three mental states significantly.
1999, 28(3): 283-285.
Abstract:
Chaotic control of a nonlinear dynamic system in the presence of model uncertainty is investigated in this paper.Control compensation is incorporated into the design of variable structure control and makes the control system robust. Simulation demonstrates the effectiveness of the approach.
Chaotic control of a nonlinear dynamic system in the presence of model uncertainty is investigated in this paper.Control compensation is incorporated into the design of variable structure control and makes the control system robust. Simulation demonstrates the effectiveness of the approach.
1999, 28(3): 286-290.
Abstract:
In this paper, under mild conditions, the steady-state models for large-scale industrial processes are obtained by using the step signals of set-points in the procedure of optimizing control, and the sufficient conditions are obtained. The identification technique has advances of high accurately simple count, and less interference to the indusrical processes, as well as less information transmission with contrast to classical identification techniques.The validity and practicabity of this complete decentralized identification are demonstrated by sedation results.
In this paper, under mild conditions, the steady-state models for large-scale industrial processes are obtained by using the step signals of set-points in the procedure of optimizing control, and the sufficient conditions are obtained. The identification technique has advances of high accurately simple count, and less interference to the indusrical processes, as well as less information transmission with contrast to classical identification techniques.The validity and practicabity of this complete decentralized identification are demonstrated by sedation results.
1999, 28(3): 291-294.
Abstract:
The variation pattern in the stator resistance of an induction motor with the coil temperature is investigated. One kind of fuzzy observers, based on fuzzy logic and for measuring instantaneous resistance is introduced.The two variables, T and △T/△t, measured at the coil ends and directly related to the stator resistance are selected as the input of fuzzy observer to simplify the fuzzy relations. Thus the real-time property of the system will be improved. The fuzzy control rules and membership functions are obtained by analyzing the experimental results. The observing accuracy can meet the requirement for the direct torque control system. It is proved to be an effective way to improve the low-speed performance of the system. The results, observed and gained through experiments are compared in the later part.
The variation pattern in the stator resistance of an induction motor with the coil temperature is investigated. One kind of fuzzy observers, based on fuzzy logic and for measuring instantaneous resistance is introduced.The two variables, T and △T/△t, measured at the coil ends and directly related to the stator resistance are selected as the input of fuzzy observer to simplify the fuzzy relations. Thus the real-time property of the system will be improved. The fuzzy control rules and membership functions are obtained by analyzing the experimental results. The observing accuracy can meet the requirement for the direct torque control system. It is proved to be an effective way to improve the low-speed performance of the system. The results, observed and gained through experiments are compared in the later part.
1999, 28(3): 295-299.
Abstract:
The equivalent circuit model of planar grid is obtained based on the analysis of quasioptical grid arrays using EMF method. The complete transmission line circuit model of the planar grid oscillator arrays is analyzed using the equivalent circuit model of the active device. The loop-gain is obtained by node-analysis method. A developed software is on the platform of Windows 95. for designing planar grid oscillator arrays. The results come out to be a good agreement with theoretical analysis and reports from home and foreign documents.
The equivalent circuit model of planar grid is obtained based on the analysis of quasioptical grid arrays using EMF method. The complete transmission line circuit model of the planar grid oscillator arrays is analyzed using the equivalent circuit model of the active device. The loop-gain is obtained by node-analysis method. A developed software is on the platform of Windows 95. for designing planar grid oscillator arrays. The results come out to be a good agreement with theoretical analysis and reports from home and foreign documents.
1999, 28(3): 300-305.
Abstract:
The double anode electron gun is designed and calculated according to the requirements for the gyrotrons by this method, which combines synthesis with analysis.A set of computer program is made.The electrode shapes, electron trajectory and electron beam parameters are also given by the computer adided design.The electron gun has such characteristics as small velocity spread, good laminar flow and small volume etc. While the later is more suitable for operating at large current.It is applied in the experiment.The experiment of using the Gurotron show that the gun has advantages over other guns.
The double anode electron gun is designed and calculated according to the requirements for the gyrotrons by this method, which combines synthesis with analysis.A set of computer program is made.The electrode shapes, electron trajectory and electron beam parameters are also given by the computer adided design.The electron gun has such characteristics as small velocity spread, good laminar flow and small volume etc. While the later is more suitable for operating at large current.It is applied in the experiment.The experiment of using the Gurotron show that the gun has advantages over other guns.
1999, 28(3): 306-310.
Abstract:
The object data flow diagram (ODFO) inherited the structure methodology supports the transition from system analysis to design, and the implementation in software development processes. This paper presents a software reuse approach based on ODFD which is the layered framework architecture including the application layer providing the requirement specification, the interface layer making the user's interfaces, the subsystem layer using the ODFD to analyze and design software, and the object component system layer constructing software.
The object data flow diagram (ODFO) inherited the structure methodology supports the transition from system analysis to design, and the implementation in software development processes. This paper presents a software reuse approach based on ODFD which is the layered framework architecture including the application layer providing the requirement specification, the interface layer making the user's interfaces, the subsystem layer using the ODFD to analyze and design software, and the object component system layer constructing software.
1999, 28(3): 311-315.
Abstract:
This paper discusses the structure of BIOS programs. The programming and operation with BIOS are also introduced, It is proved that SEA M as reliable as DRAM in the industrial controller. It is good for anti-industrial interference with good quality of the electric power and the suitable mainboard with its special BIOS. It is easy to change tile program and control parameters through disk with monitor. So, special industrial computers can be made up of common personal computers' mother boards.
This paper discusses the structure of BIOS programs. The programming and operation with BIOS are also introduced, It is proved that SEA M as reliable as DRAM in the industrial controller. It is good for anti-industrial interference with good quality of the electric power and the suitable mainboard with its special BIOS. It is easy to change tile program and control parameters through disk with monitor. So, special industrial computers can be made up of common personal computers' mother boards.
1999, 28(3): 316-319.
Abstract:
If different synthetical evaluation methods are employed to evaluate some target, different conclusions may occur This undoubtedly poses a barrier to some economic evaluation tasks. This paper discusses the choice of an optimum evaluation method for those targets whose indicatrixes are assumed to be distributed in certain pattern. Furtherly, this paper presents an approach to the choice of the optimum methods.
If different synthetical evaluation methods are employed to evaluate some target, different conclusions may occur This undoubtedly poses a barrier to some economic evaluation tasks. This paper discusses the choice of an optimum evaluation method for those targets whose indicatrixes are assumed to be distributed in certain pattern. Furtherly, this paper presents an approach to the choice of the optimum methods.
1999, 28(3): 320-323.
Abstract:
In general, suppose the controlling process of the single source for ATM MUX be a two-state Markov chain in the fluid mode, the superposition to the ATM MUX is a MMP whose controlling process is a muti-state, continuous, irreducible MC.It is inconvenient to study the content of the buffer because of the large number of state. To solve this problem, this paper gives a method to match the MMP with a simple two-state semi-MMP.
In general, suppose the controlling process of the single source for ATM MUX be a two-state Markov chain in the fluid mode, the superposition to the ATM MUX is a MMP whose controlling process is a muti-state, continuous, irreducible MC.It is inconvenient to study the content of the buffer because of the large number of state. To solve this problem, this paper gives a method to match the MMP with a simple two-state semi-MMP.
1999, 28(3): 324-328.
Abstract:
A polarographic investigation of direct electroreduction disaccharide and monosaccharide on DME to corresponding polyalcohols in alkaline acquous media is described. The experimental results show that the electrode process is controlled by the mixture control of charge transfer and kinetical steps with the adsorption of sugar to the surface of mercury electrode. A practically 100% yield in corresponding polyalcohols and 60%, 74% and 83% yield in current for lactose, glucose and fructose respectively are realized. Specially, the investigation results of electroreduction disaccharide are reported in this paper.The possible electroreduction mechanism of sugars is proposed.
A polarographic investigation of direct electroreduction disaccharide and monosaccharide on DME to corresponding polyalcohols in alkaline acquous media is described. The experimental results show that the electrode process is controlled by the mixture control of charge transfer and kinetical steps with the adsorption of sugar to the surface of mercury electrode. A practically 100% yield in corresponding polyalcohols and 60%, 74% and 83% yield in current for lactose, glucose and fructose respectively are realized. Specially, the investigation results of electroreduction disaccharide are reported in this paper.The possible electroreduction mechanism of sugars is proposed.
1999, 28(3): 329-332.
Abstract:
The paper studies the magnetic focusing electron gun of CRT used in a new 48-inch rear color projection TV. The dual-focusing system in electron gun is developed, which is composed of electrostatic pre-focusing and electromagnetic focusing lens. As a result, on the green YAG phosphor screen, beam spot is 0.065 mm-0.080mm only at cathode currents of o.5 mA-1.0 mA respectively.
The paper studies the magnetic focusing electron gun of CRT used in a new 48-inch rear color projection TV. The dual-focusing system in electron gun is developed, which is composed of electrostatic pre-focusing and electromagnetic focusing lens. As a result, on the green YAG phosphor screen, beam spot is 0.065 mm-0.080mm only at cathode currents of o.5 mA-1.0 mA respectively.
