ISSN 
2002 Vol. 31, No. 5
2002, 31(5): 441-446.
Abstract:
On the basis of the transmission system model given in this paper, the impact of the parameters, such as input power, dispersion compensation coefficient, dispersion compensation factor, length of standard single mode fiber and pulse duty cycle on the system performance, which is evaluated by bit error rate and Q value of the system, is studied through extensive numerical simulation. Then a 9-span optical fiber transmission system with optimal parameters is designed.The simulation results are helpful to design systems based on bit rate of 40Gb/s or above.
On the basis of the transmission system model given in this paper, the impact of the parameters, such as input power, dispersion compensation coefficient, dispersion compensation factor, length of standard single mode fiber and pulse duty cycle on the system performance, which is evaluated by bit error rate and Q value of the system, is studied through extensive numerical simulation. Then a 9-span optical fiber transmission system with optimal parameters is designed.The simulation results are helpful to design systems based on bit rate of 40Gb/s or above.
2002, 31(5): 447-451.
Abstract:
The paper studies the characteristics of the discrete optical fiber Raman amplifier on the base of PTDS, which is a simulation platform for optical transmission system emulation. Consequently, a discrete optical fiber Raman amplifier whose parameters have been optimized has been designed. Then a comparison of the improvement on the system capability has been carried through between EDFA and discrete FRA. From the comparison, the advantage of discrete FRA has appeared. At the end of the paper a project about achieving all Raman amplification in the optical fiber communication is presented.
The paper studies the characteristics of the discrete optical fiber Raman amplifier on the base of PTDS, which is a simulation platform for optical transmission system emulation. Consequently, a discrete optical fiber Raman amplifier whose parameters have been optimized has been designed. Then a comparison of the improvement on the system capability has been carried through between EDFA and discrete FRA. From the comparison, the advantage of discrete FRA has appeared. At the end of the paper a project about achieving all Raman amplification in the optical fiber communication is presented.
2002, 31(5): 452-455.
Abstract:
The paper simply introduces the architecture and foundational principle of SAW (Surface Acoustic Wave) Filter, then by the theory of electronic network analyses and synthesis, puts emphasis on the analyses and design about one-port SAW resonator and SAW Filter applied to the RF (Radio Frequency) part of wireless mobile communication system.
The paper simply introduces the architecture and foundational principle of SAW (Surface Acoustic Wave) Filter, then by the theory of electronic network analyses and synthesis, puts emphasis on the analyses and design about one-port SAW resonator and SAW Filter applied to the RF (Radio Frequency) part of wireless mobile communication system.
2002, 31(5): 456-459.
Abstract:
Active networking is a powerful and flexible new networking Architecture.While this new technology presents opportunities for innovative networking services,it also presents significant security challenges. This paper introduces the technology of active networks and the functions of the key establishment protocol(KEP)firstly. Then describes the management of keys and how to produce a key & initialization vector. Finaly, a KTC-based key establishment protocol for active networks nodes is proposed.
Active networking is a powerful and flexible new networking Architecture.While this new technology presents opportunities for innovative networking services,it also presents significant security challenges. This paper introduces the technology of active networks and the functions of the key establishment protocol(KEP)firstly. Then describes the management of keys and how to produce a key & initialization vector. Finaly, a KTC-based key establishment protocol for active networks nodes is proposed.
2002, 31(5): 460-464.
Abstract:
This paper presents the design of frequency_sampling FIR digital filter based on multirate conception for removal of base_line wander and power_line interference from the ECG. We can design high performance digital filter which can be used to resolve the problems involving present filters, such as difficulty of controlling cutoff frequency,large ripple in stop_band and pass_band, too narrow stop bandwidth for removing power_line interference, sensitivity to the fluctuation of power frequency, or the low frequency part of the ECG being cut off too much when removing base_line wander. This scheme can also avoid distortion resulting from non-linear filtering when compared with ⅡR digital filter or analog filter.
This paper presents the design of frequency_sampling FIR digital filter based on multirate conception for removal of base_line wander and power_line interference from the ECG. We can design high performance digital filter which can be used to resolve the problems involving present filters, such as difficulty of controlling cutoff frequency,large ripple in stop_band and pass_band, too narrow stop bandwidth for removing power_line interference, sensitivity to the fluctuation of power frequency, or the low frequency part of the ECG being cut off too much when removing base_line wander. This scheme can also avoid distortion resulting from non-linear filtering when compared with ⅡR digital filter or analog filter.
2002, 31(5): 465-469.
Abstract:
A circular array realizing multibeam is gived by modified traditional Bulter network.The array is made up of vertical eight half-wavelength antennas.Changing the feedingport,it can control the beam direction.Because of additional eight phase splitters,the array can provided eight parallel beam covered the whole horizontal surface,and use for estimation of DoA.
A circular array realizing multibeam is gived by modified traditional Bulter network.The array is made up of vertical eight half-wavelength antennas.Changing the feedingport,it can control the beam direction.Because of additional eight phase splitters,the array can provided eight parallel beam covered the whole horizontal surface,and use for estimation of DoA.
2002, 31(5): 470-474.
Abstract:
The software cold-test method simulating to obtain high frequency characteristic data including dispersion,interaction impedance and attenuation of coupled-cavity slow-wave circuit by MAFIA simulation is discussed considering effect of tube-envelop in the TWT. The precision of dispersion is increased to 0.29%. Then the simulation result is obtained more consistent with experiment data than the method that ignoring effect of tube-envelop. It is proved that computer cold-test simulation method may replace the experiment method.
The software cold-test method simulating to obtain high frequency characteristic data including dispersion,interaction impedance and attenuation of coupled-cavity slow-wave circuit by MAFIA simulation is discussed considering effect of tube-envelop in the TWT. The precision of dispersion is increased to 0.29%. Then the simulation result is obtained more consistent with experiment data than the method that ignoring effect of tube-envelop. It is proved that computer cold-test simulation method may replace the experiment method.
2002, 31(5): 475-478.
Abstract:
Based on the theory of mode coupling, 8mm high power Gyroklystron outer TE01~TE11 mode converter is discussed in this paper. Adopting structure of the waveguide axis curved and radius tapered with different phase rematch technique, the reliable optimal geometry parameter can be obtained. This results contribute to design 8mm gyroklystron TE01~TE11 circular waveguide mode converter with tighten and high efficiency exceeding 98%.
Based on the theory of mode coupling, 8mm high power Gyroklystron outer TE01~TE11 mode converter is discussed in this paper. Adopting structure of the waveguide axis curved and radius tapered with different phase rematch technique, the reliable optimal geometry parameter can be obtained. This results contribute to design 8mm gyroklystron TE01~TE11 circular waveguide mode converter with tighten and high efficiency exceeding 98%.
2002, 31(5): 479-484.
Abstract:
Considering azimuthal space harmonics, the finite size vane model is suggested for vane-loaded helical slow-wave structures in this paper. Two vane-loaded helical slow-wave structures of TWT are calculated by the derived dispersion equations. The calculating results are compared with the results of measurement and the calculating results of simple vane model. The influence on dispersion characteristics is analyzed for different center angle of the vanes, radius of the tip of the vanes and radius of metal envelope.
Considering azimuthal space harmonics, the finite size vane model is suggested for vane-loaded helical slow-wave structures in this paper. Two vane-loaded helical slow-wave structures of TWT are calculated by the derived dispersion equations. The calculating results are compared with the results of measurement and the calculating results of simple vane model. The influence on dispersion characteristics is analyzed for different center angle of the vanes, radius of the tip of the vanes and radius of metal envelope.
2002, 31(5): 485-489.
Abstract:
This paper summarizes the dynamic developing trend of these medical image processing, further describes the latest research issues:3D visualization and the medical image compression based on PACS. On the basis of analyzing the relative technologies, the problems have been put forward what we are facing with the development of medical processing technology. In the end we prospected their research foreground, it's the trend that people will be paying more and more attention to the technology on medical image processing.
This paper summarizes the dynamic developing trend of these medical image processing, further describes the latest research issues:3D visualization and the medical image compression based on PACS. On the basis of analyzing the relative technologies, the problems have been put forward what we are facing with the development of medical processing technology. In the end we prospected their research foreground, it's the trend that people will be paying more and more attention to the technology on medical image processing.
2002, 31(5): 490-493.
Abstract:
This article introduce the theory of using the basic mathematics morphologic methods and the flat structuring element to average the image's grey degree and wipe off the yawp and show the using rule of structuring element based on the image's detail as well as the effect. This article also emphasizes the process of integrating the method of using improved Sobel operator and mathematics morphological to pick up the image target' edge in the medical image processing. At the same time, I put forward a algorithm for choosing the Sobel's magnitude on the basis of the image region's gray variance and give a useful way for these and a example.
This article introduce the theory of using the basic mathematics morphologic methods and the flat structuring element to average the image's grey degree and wipe off the yawp and show the using rule of structuring element based on the image's detail as well as the effect. This article also emphasizes the process of integrating the method of using improved Sobel operator and mathematics morphological to pick up the image target' edge in the medical image processing. At the same time, I put forward a algorithm for choosing the Sobel's magnitude on the basis of the image region's gray variance and give a useful way for these and a example.
2002, 31(5): 494-496.
Abstract:
This paper presents theoretical analysis circuit design of doubler using two beam-lead Schottky-barrier diodes as varistors. Influence of cavity to the microstrip circuit is fully considered during the CAD process and accurate model is set up. Input frequency is 13~20 GHz. Output frequency is 26~40 GHz. Conversion loss is better than 11.2±1.8 dB. It can extend microwave signal source to Ka-band.
This paper presents theoretical analysis circuit design of doubler using two beam-lead Schottky-barrier diodes as varistors. Influence of cavity to the microstrip circuit is fully considered during the CAD process and accurate model is set up. Input frequency is 13~20 GHz. Output frequency is 26~40 GHz. Conversion loss is better than 11.2±1.8 dB. It can extend microwave signal source to Ka-band.
2002, 31(5): 497-501.
Abstract:
The second-order proximate model on closed-loop system of Micromachined Capacitive Accelerometer is set up. Influence of the gain and bandwidth of servo-circuit on the dynamic behavior of closed-loop system is analyzed. The method to compensate dynamic performance of servo-system by adjusting the parameters of servo-circuit is put forward. The computational methods of start-up response time and output error of servo-system are given in different inputs.
The second-order proximate model on closed-loop system of Micromachined Capacitive Accelerometer is set up. Influence of the gain and bandwidth of servo-circuit on the dynamic behavior of closed-loop system is analyzed. The method to compensate dynamic performance of servo-system by adjusting the parameters of servo-circuit is put forward. The computational methods of start-up response time and output error of servo-system are given in different inputs.
2002, 31(5): 502-506.
Abstract:
In this paper, the conception, the characteristic and key technique of Intrusion Detection System and Data Mining are introduced. And the main data source of information collection in the Intrusion Detection System is analyzed. This paper combines the shortcoming of the framework of traditional Intrusion Detection, and also specifies a framework of a self-training and self-development Intrusion Detection System based on Data Mining. The framework adopts different methods of Data Mining to identify according to different information.
In this paper, the conception, the characteristic and key technique of Intrusion Detection System and Data Mining are introduced. And the main data source of information collection in the Intrusion Detection System is analyzed. This paper combines the shortcoming of the framework of traditional Intrusion Detection, and also specifies a framework of a self-training and self-development Intrusion Detection System based on Data Mining. The framework adopts different methods of Data Mining to identify according to different information.
2002, 31(5): 507-511.
Abstract:
Conforming to the JMX specification 1.0, this paper analyzes the technology background and the architecture of JMX, and discusses the implementation method of the Mbean object and the design of the core of dynamic management service. In particular, the paper also discusses the design of remote management communication interface and Notification mechanism based on Java event model, and extends the standard MBeanServer to be a persistent and remote management service.
Conforming to the JMX specification 1.0, this paper analyzes the technology background and the architecture of JMX, and discusses the implementation method of the Mbean object and the design of the core of dynamic management service. In particular, the paper also discusses the design of remote management communication interface and Notification mechanism based on Java event model, and extends the standard MBeanServer to be a persistent and remote management service.
2002, 31(5): 512-516.
Abstract:
This paper introduces the related theory and model about using JSP to develop Electronic Commerce system upon IBM WebSphere,presented an user identification tactics based on Web,modified the method that needs user to input their password by themselves when been identified, the process follow the criterion of J2EE, run through three layers of Web application model system structure, and realize identifying in SP, it is useful in improving the security of the electronic commerce.
This paper introduces the related theory and model about using JSP to develop Electronic Commerce system upon IBM WebSphere,presented an user identification tactics based on Web,modified the method that needs user to input their password by themselves when been identified, the process follow the criterion of J2EE, run through three layers of Web application model system structure, and realize identifying in SP, it is useful in improving the security of the electronic commerce.
2002, 31(5): 517-522.
Abstract:
Based on the analysis of the algorithm, performance and problem of a novel certificate revocation approach called the windowed revocation mechanism, a new and more efficient certificate revocation mechanism is proposed in this paper. The new mechanism integrates windowed certificate revocation and Delta-CRL mechanism, and uses effective method to avoid replay-attack.It satisfies the scalability and flexibility requirements of certificate revocation mechanism and, as the same time, can provide near real-time certificate status when required. The design and performance of the new mechanism is analyzed in this paper.
Based on the analysis of the algorithm, performance and problem of a novel certificate revocation approach called the windowed revocation mechanism, a new and more efficient certificate revocation mechanism is proposed in this paper. The new mechanism integrates windowed certificate revocation and Delta-CRL mechanism, and uses effective method to avoid replay-attack.It satisfies the scalability and flexibility requirements of certificate revocation mechanism and, as the same time, can provide near real-time certificate status when required. The design and performance of the new mechanism is analyzed in this paper.
2002, 31(5): 523-528.
Abstract:
This paper proposes the methods of design and implementation of a type of versatile video-based digital monitoring system. This system is composed of software and hardware, which is very flexible and suitable for varieties of practical channel situations. The key technologies of the system such as moving picture capture, video coding & decoding, video real-time display on screen, video streams control, video-related device control will be discussed emphatically. The design and implementation of computer serial communication, TCP and UDP, the communication and synchronization of multithread are also discussed in this thesis. In each part of related theories, shows the Windows-based realization methods by using Visual C++.
This paper proposes the methods of design and implementation of a type of versatile video-based digital monitoring system. This system is composed of software and hardware, which is very flexible and suitable for varieties of practical channel situations. The key technologies of the system such as moving picture capture, video coding & decoding, video real-time display on screen, video streams control, video-related device control will be discussed emphatically. The design and implementation of computer serial communication, TCP and UDP, the communication and synchronization of multithread are also discussed in this thesis. In each part of related theories, shows the Windows-based realization methods by using Visual C++.
2002, 31(5): 529-533.
Abstract:
This paper studies the reason of integrating XML and CORBA. The characteristics of XML and CORBA specification are described. There are four modes of integrating XML and CORBA:XML as Strings, DOM/Value mapping, SOAP and Web services, then analyses four implement methods and their weakness, point out the Web services is the best methods which provides the method to integrate the loose-couple Web application with the tight-couple CORBA application.
This paper studies the reason of integrating XML and CORBA. The characteristics of XML and CORBA specification are described. There are four modes of integrating XML and CORBA:XML as Strings, DOM/Value mapping, SOAP and Web services, then analyses four implement methods and their weakness, point out the Web services is the best methods which provides the method to integrate the loose-couple Web application with the tight-couple CORBA application.
2002, 31(5): 534-538.
Abstract:
In this paper, the differential equation of an artificial neural network model is solved by solving a simple one dimension differential equation.The solutions of the neural network that is obtained are represented by the eigenvalues and eigenvectors of the symmetric matrix.Then the other solutions in special conditions are obtained using the solutions in general conditions.In special condtions,the neural network is employed to compute out all eigenvalues and eigenvectors by many dissertations.Finally,the asymptotic stable behavior is analyzed using the solutions.
In this paper, the differential equation of an artificial neural network model is solved by solving a simple one dimension differential equation.The solutions of the neural network that is obtained are represented by the eigenvalues and eigenvectors of the symmetric matrix.Then the other solutions in special conditions are obtained using the solutions in general conditions.In special condtions,the neural network is employed to compute out all eigenvalues and eigenvectors by many dissertations.Finally,the asymptotic stable behavior is analyzed using the solutions.
2002, 31(5): 539-541.
Abstract:
This article is based on the notions and the properties of a rough subsemigroup, rough left ideal,rough right ideal,rough two-sided ideal and rough bi-ideal in a semigroup.It combines the upper and lower approximations in a set satisfy the monotony, discussing some properties of the product of these two subsets in semigroups according to the properties of some especial single subsets such as subsemigroup and ideal, then the rigorous proof was given.Thus the rough theory in semigroups are completed and perfected.
This article is based on the notions and the properties of a rough subsemigroup, rough left ideal,rough right ideal,rough two-sided ideal and rough bi-ideal in a semigroup.It combines the upper and lower approximations in a set satisfy the monotony, discussing some properties of the product of these two subsets in semigroups according to the properties of some especial single subsets such as subsemigroup and ideal, then the rigorous proof was given.Thus the rough theory in semigroups are completed and perfected.
2002, 31(5): 542-545.
Abstract:
Jacobi and Gauss-Seidel iterations for solving large linear system Ax=b are studied. Based on the concept of the doubly diagonal dominance, new upper bound for the spectral radius of Jacobi and Gauss-Seidel iterations are presented. Results obtained improve the known corresponding results and are suited to extended matrices. Finally, two numerical examples are given for illustrating advantage results in this paper.
Jacobi and Gauss-Seidel iterations for solving large linear system Ax=b are studied. Based on the concept of the doubly diagonal dominance, new upper bound for the spectral radius of Jacobi and Gauss-Seidel iterations are presented. Results obtained improve the known corresponding results and are suited to extended matrices. Finally, two numerical examples are given for illustrating advantage results in this paper.
