ISSN 
2002 Vol. 31, No. 4
2002, 31(4): 331-335.
Abstract:
Using sub-sampling theorem of multiple banpass signals and digital frequency converting techniques, multi-band-pass signals can be directly sampled and processed using no aliasing sampling rate. If sampling rate is lower than the two times of the maximum frequency of the signal, the signal-to-noise ratio will become worse. The relationships of signal-to-noise ratio of sampled signal, analog filter before analog-to-digital converter and sampling rate have been discussed, the results of the discussion have instructiveness for the design of digital receivers.
Using sub-sampling theorem of multiple banpass signals and digital frequency converting techniques, multi-band-pass signals can be directly sampled and processed using no aliasing sampling rate. If sampling rate is lower than the two times of the maximum frequency of the signal, the signal-to-noise ratio will become worse. The relationships of signal-to-noise ratio of sampled signal, analog filter before analog-to-digital converter and sampling rate have been discussed, the results of the discussion have instructiveness for the design of digital receivers.
2002, 31(4): 336-339.
Abstract:
Through domain decomposition method, the method of lines combined with the finite-difference method is used to calculate the capacitance and inductance matrices of the multilayered multiconductor interconnections. The subregion with pure dielectric layers is analyzed by method of lines, while the subregion with conductors is analyzed by finite-difference method to take advantage fully the superiorities of these two methods. Numerical results show that the method in this paper is efficient, and the computing time is unrelated to the thickness of the pure dielectric layers.
Through domain decomposition method, the method of lines combined with the finite-difference method is used to calculate the capacitance and inductance matrices of the multilayered multiconductor interconnections. The subregion with pure dielectric layers is analyzed by method of lines, while the subregion with conductors is analyzed by finite-difference method to take advantage fully the superiorities of these two methods. Numerical results show that the method in this paper is efficient, and the computing time is unrelated to the thickness of the pure dielectric layers.
2002, 31(4): 340-344.
Abstract:
The profile of a two-dimensional axi-symmetric inhomogeneous medium is reconstructed by using the distorted Born iterative method and multi-grid technique. In the previous inversion procedure, we consider the whole objective area as one grid, and the mean value of the objective function is obtained approximately by the distorted Born iterative method; then the size of the discretization grid inside object gradually is reduced, the results reconstructed in the last level grid is used as new background medium and the profile reconstruction of the objects is solved continuously by the distorted Born iterative method. The numerical examples show that the new method has the robust feature, the computational time of the inversion procedure is reduced vastly and more accurate inversion results of the higher-contrast scattering objects can be obtained.
The profile of a two-dimensional axi-symmetric inhomogeneous medium is reconstructed by using the distorted Born iterative method and multi-grid technique. In the previous inversion procedure, we consider the whole objective area as one grid, and the mean value of the objective function is obtained approximately by the distorted Born iterative method; then the size of the discretization grid inside object gradually is reduced, the results reconstructed in the last level grid is used as new background medium and the profile reconstruction of the objects is solved continuously by the distorted Born iterative method. The numerical examples show that the new method has the robust feature, the computational time of the inversion procedure is reduced vastly and more accurate inversion results of the higher-contrast scattering objects can be obtained.
2002, 31(4): 345-348.
Abstract:
The paper constructed one of transition probability matrix based Markov chain theory and random theory in discrete time,and we divide the state of traffic parameters of communication into N levels according to characteristic of communication traffic parameters that will be forecasted. Therefore, we get a finite state space S={1,2,…, N}. As a result,a forecasting model about traffic parameters of communication was established with transition probablilty matrix and random theory,and the reliablilty of the model was verified through two real examples on communication networks.
The paper constructed one of transition probability matrix based Markov chain theory and random theory in discrete time,and we divide the state of traffic parameters of communication into N levels according to characteristic of communication traffic parameters that will be forecasted. Therefore, we get a finite state space S={1,2,…, N}. As a result,a forecasting model about traffic parameters of communication was established with transition probablilty matrix and random theory,and the reliablilty of the model was verified through two real examples on communication networks.
2002, 31(4): 349-355.
Abstract:
This paper proposes two models of discrete recurrent neural networks to study the problem of eigensubspace estimation for positive definite symmetric matrix. The first model is a class of nonlinear neural networks. It is used for estimating the largest eigenvalue and one of its corresponding eigenvectors. The second model is a class of linear neural networks which estimates the eigensubspace corresponding to the largest eigenvalue. Dynamic properties of these two classes of discrete recurrent neural network models are studied and used for eigensubspace estimation.
This paper proposes two models of discrete recurrent neural networks to study the problem of eigensubspace estimation for positive definite symmetric matrix. The first model is a class of nonlinear neural networks. It is used for estimating the largest eigenvalue and one of its corresponding eigenvectors. The second model is a class of linear neural networks which estimates the eigensubspace corresponding to the largest eigenvalue. Dynamic properties of these two classes of discrete recurrent neural network models are studied and used for eigensubspace estimation.
2002, 31(4): 356-361.
Abstract:
The paper study the power control of the motion satellite, based on the broadcast delay feture of the motion satellite communication system. A moment-generating-function based approach is used in this paper for analyzing the system performance with imperfect power control. Compared with the previous work,to bring down the error of power control, analyzing the channel model, calculating the offset factor,giving the result of simulation, our whole evaluation procedures are easily formulated and the average error performance in compact forms can be obtained to ease the examination of effects of different system arameters.
The paper study the power control of the motion satellite, based on the broadcast delay feture of the motion satellite communication system. A moment-generating-function based approach is used in this paper for analyzing the system performance with imperfect power control. Compared with the previous work,to bring down the error of power control, analyzing the channel model, calculating the offset factor,giving the result of simulation, our whole evaluation procedures are easily formulated and the average error performance in compact forms can be obtained to ease the examination of effects of different system arameters.
2002, 31(4): 362-365.
Abstract:
The design of power transformer is almost the most important issue in switch mode power supply. If the transformer in switch mode power supply working at high frequency isn't designed carefully, the ultimate goal cannot reach. In this paper, we analyzed the design theory of high frequency transformer, and proposed a optimum design procedure which used in this case. With its help, we can decrease power loss and enhance the performance of the switch mode power supply.
The design of power transformer is almost the most important issue in switch mode power supply. If the transformer in switch mode power supply working at high frequency isn't designed carefully, the ultimate goal cannot reach. In this paper, we analyzed the design theory of high frequency transformer, and proposed a optimum design procedure which used in this case. With its help, we can decrease power loss and enhance the performance of the switch mode power supply.
2002, 31(4): 366-368.
Abstract:
Problems of the storage and process of phase graph information are discuss in this paper. Software of digital process on alloy phase equilibrium is developed based on VB6.0 language desktop. It was applied in phase calculation under phase equilibrium condition, and analysis on phase graph on computer, difficulties of data inquire and data process in alloy characteristic analysis are solved. Due to using the engineering material, the quality and work efficiency are raised noticeably.
Problems of the storage and process of phase graph information are discuss in this paper. Software of digital process on alloy phase equilibrium is developed based on VB6.0 language desktop. It was applied in phase calculation under phase equilibrium condition, and analysis on phase graph on computer, difficulties of data inquire and data process in alloy characteristic analysis are solved. Due to using the engineering material, the quality and work efficiency are raised noticeably.
2002, 31(4): 369-373.
Abstract:
A new type parallel machine tool, which utilizes a 3dof spatial parallel mechanism as main feed machanism, is proposed in this paper. The input-output equation of displacement analysis for the main feed mechanism of parallel machine tool is established. An analytical expression for determining singularity configuration which is a polynomial equation is set, and the numeric-symbolic manipulating technique is introduced in the paper. Analytical expressions of numeric-symbolic form for each coefficient of the ploynomial equation are derived. The section curve graph of a singularity surface is drawn. A numerical example of singularity configuration analysis is given for illustration.
A new type parallel machine tool, which utilizes a 3dof spatial parallel mechanism as main feed machanism, is proposed in this paper. The input-output equation of displacement analysis for the main feed mechanism of parallel machine tool is established. An analytical expression for determining singularity configuration which is a polynomial equation is set, and the numeric-symbolic manipulating technique is introduced in the paper. Analytical expressions of numeric-symbolic form for each coefficient of the ploynomial equation are derived. The section curve graph of a singularity surface is drawn. A numerical example of singularity configuration analysis is given for illustration.
2002, 31(4): 374-378.
Abstract:
The present essay dissects the algorithm of the linear acceleration at the centre of gravity of the platform of the motion loading system, and also analyses the relations of hydraulic servo actuator's travel distance, the aircraft's specific force and the aircraft's rotational rate. The essay also suggests the basis of motion equation modeling, and discusses the simulator's six-degree-of-freedom motion system's combination principles by the means of the hardware and software, and all these make the foundation of the research of flight simulator hydraulic servo control in improving performance of overload protection.
The present essay dissects the algorithm of the linear acceleration at the centre of gravity of the platform of the motion loading system, and also analyses the relations of hydraulic servo actuator's travel distance, the aircraft's specific force and the aircraft's rotational rate. The essay also suggests the basis of motion equation modeling, and discusses the simulator's six-degree-of-freedom motion system's combination principles by the means of the hardware and software, and all these make the foundation of the research of flight simulator hydraulic servo control in improving performance of overload protection.
2002, 31(4): 379-382.
Abstract:
According to the realistic requirement of telecom operators, the basic architecture of BSS/OSS was given out. The architecture consisted of three management domains:customer management domain, service management domain and network/resource management. The service cell components of each domain were defined to modify the architecture. Using the concept of abstract components set, the service-handling chart of BSS/OSS was released based on the characteristics of telecom operators service. The information model of BSS/OSS was designed in final.
According to the realistic requirement of telecom operators, the basic architecture of BSS/OSS was given out. The architecture consisted of three management domains:customer management domain, service management domain and network/resource management. The service cell components of each domain were defined to modify the architecture. Using the concept of abstract components set, the service-handling chart of BSS/OSS was released based on the characteristics of telecom operators service. The information model of BSS/OSS was designed in final.
2002, 31(4): 383-386.
Abstract:
Virtual private network is the key technology of next generation Internet, L2TP is a dialup virtual private network specification which was defined by IETF. Its design and implementation are very significant. From the L2TP, basic technology and two kinds of servers of L2TP(LAC server and L2TP net server) are introduced and L2TP function models(authentication model、log model and LAC model) on this are expatiated. Based on this, a L2TP scheme was suggested and developed on a few UNIX latforms.
Virtual private network is the key technology of next generation Internet, L2TP is a dialup virtual private network specification which was defined by IETF. Its design and implementation are very significant. From the L2TP, basic technology and two kinds of servers of L2TP(LAC server and L2TP net server) are introduced and L2TP function models(authentication model、log model and LAC model) on this are expatiated. Based on this, a L2TP scheme was suggested and developed on a few UNIX latforms.
2002, 31(4): 387-392.
Abstract:
This paper studies wireless application protocol four components of security frame and base components of security frame architecture. Analyses three implement methods of End_to_End security frame and their securities. Service Levels and running flow of wireless transport layer security are described. WTLS state machine is designed by message event driven, design and implement WTLS of mobile terminal.
This paper studies wireless application protocol four components of security frame and base components of security frame architecture. Analyses three implement methods of End_to_End security frame and their securities. Service Levels and running flow of wireless transport layer security are described. WTLS state machine is designed by message event driven, design and implement WTLS of mobile terminal.
2002, 31(4): 393-398.
Abstract:
Intelligent voiced book is the application technique based on the core processor the voice chip FS20C01; This paper introduces the good qualities and system software structure constituting of the Intelligent voiced book; explains the system hardware constituting, narrates the arithmetic of the card identification, keystroke identification, judging help in the implemented procedure of the studying, examining and helping function; then introduces the software implemented scheme of the voice synthesis arithmetic based on the voiced chip FS20C01.
Intelligent voiced book is the application technique based on the core processor the voice chip FS20C01; This paper introduces the good qualities and system software structure constituting of the Intelligent voiced book; explains the system hardware constituting, narrates the arithmetic of the card identification, keystroke identification, judging help in the implemented procedure of the studying, examining and helping function; then introduces the software implemented scheme of the voice synthesis arithmetic based on the voiced chip FS20C01.
2002, 31(4): 399-403.
Abstract:
PWICE is a usage-based Web personalization system taking account the full spectrum of Web mining technique. The system uses transaction clustering,usage clustering,and association rule discovery to extract usage knowledge from server log file, and combine with the current status of an ongoing Web activity to perform real-time personalization. Experiments show the system has good performance.
PWICE is a usage-based Web personalization system taking account the full spectrum of Web mining technique. The system uses transaction clustering,usage clustering,and association rule discovery to extract usage knowledge from server log file, and combine with the current status of an ongoing Web activity to perform real-time personalization. Experiments show the system has good performance.
2002, 31(4): 404-408.
Abstract:
By studying the construction of the RTT latency, alinear expression between the RTT latency and the packet size is presented. Then pathchar,traditional bandwidth measurement algorithm,based on the relationship between the RTT latency and the packet size, is analyzed particularly. But pathchar can not measure the asymmetric link bandwidth. To solve this problem, Asy_pathchar, a new algorithm, is put forward, which can measure each hop's link bandwidth in both directions in an IP network using the UDP packet and ICMP packet.Finally an experiment is given to validate the new algorithm.
By studying the construction of the RTT latency, alinear expression between the RTT latency and the packet size is presented. Then pathchar,traditional bandwidth measurement algorithm,based on the relationship between the RTT latency and the packet size, is analyzed particularly. But pathchar can not measure the asymmetric link bandwidth. To solve this problem, Asy_pathchar, a new algorithm, is put forward, which can measure each hop's link bandwidth in both directions in an IP network using the UDP packet and ICMP packet.Finally an experiment is given to validate the new algorithm.
2002, 31(4): 409-412.
Abstract:
This article puts forward a sort of new pattern QoS route algorithm based on the mathematical mode of reliability and average trouble-free performance of network accessing by analyzing communication network, Emulation experiment implemented indicates this route algorithm can improve the performance of the network service ultimately and realize the equity of network accessing well.
This article puts forward a sort of new pattern QoS route algorithm based on the mathematical mode of reliability and average trouble-free performance of network accessing by analyzing communication network, Emulation experiment implemented indicates this route algorithm can improve the performance of the network service ultimately and realize the equity of network accessing well.
2002, 31(4): 413-417.
Abstract:
In this paper, the model is reduced and solved by a pivoting-based algorithm proposed by the authors. This algorithm is simpler than the widely used simplex method and requires less amounts of computaion. The experimental results by using 70 weekly data of 1 072 stocks from Shanghai and Shenzhen stock markets of China indicate that 1 274 pivoting operations are required to obtain 20 different optimal portfolios if no upper bound restrictions for every stocks and 1 570 pivoting operations are required if the ratio of each stock is no more than 10%, in which one pivoting operation required about 1 141×71 andditions and multiplications.
In this paper, the model is reduced and solved by a pivoting-based algorithm proposed by the authors. This algorithm is simpler than the widely used simplex method and requires less amounts of computaion. The experimental results by using 70 weekly data of 1 072 stocks from Shanghai and Shenzhen stock markets of China indicate that 1 274 pivoting operations are required to obtain 20 different optimal portfolios if no upper bound restrictions for every stocks and 1 570 pivoting operations are required if the ratio of each stock is no more than 10%, in which one pivoting operation required about 1 141×71 andditions and multiplications.
2002, 31(4): 418-421.
Abstract:
In the persons two-object auction, the necessary condition for the bidders to participate in the auction is determined based on random estimate. After comparing this necessary condition with the one based on real estimate, then two similar conclusions have been made. Meanwhile the risks absorbed by the bidders because of their wrong estimate is analyzed. It is concluded that there is a close relationship between the risks and estimate accuracy made by the bidders.
In the persons two-object auction, the necessary condition for the bidders to participate in the auction is determined based on random estimate. After comparing this necessary condition with the one based on real estimate, then two similar conclusions have been made. Meanwhile the risks absorbed by the bidders because of their wrong estimate is analyzed. It is concluded that there is a close relationship between the risks and estimate accuracy made by the bidders.
2002, 31(4): 422-425.
Abstract:
In this paper, a new topological space as well as minimal families topological space is established on completely distributive lattices by using the results of the minimal families, the result that the largest standard minimal families are only nontrivial open sets on this topology is proved.The properties and the sufficient and necessary condition for functional continuity on the minimal families topological space shall be given, the relation between the continuity and the generalized order homomorphism under the new topological space is discussed, the result that the standard minimal families mapping on completely distributive lattices is the generalized order homomorphism is obtained.
In this paper, a new topological space as well as minimal families topological space is established on completely distributive lattices by using the results of the minimal families, the result that the largest standard minimal families are only nontrivial open sets on this topology is proved.The properties and the sufficient and necessary condition for functional continuity on the minimal families topological space shall be given, the relation between the continuity and the generalized order homomorphism under the new topological space is discussed, the result that the standard minimal families mapping on completely distributive lattices is the generalized order homomorphism is obtained.
2002, 31(4): 426-428.
Abstract:
In this paper, a rough neural network system is given and applied in Electrocardiogram auto-recognition. Based on medical requires, this paper has picked up the characteristic parameters of signals from Massachusettes Institute of Technology (database). According to Rough sets theory, the attributes are optimized and studied with BP neural network. In the end, the Electrocardiogram samples are classified with those characteristic parameters. The result shows that the right ratio goes to 90%. The experiment shows that the system has the advantages of fast computation and easy realization and the system is better than other methods in optimizing attributes and enhancing the right ratio of classification.
In this paper, a rough neural network system is given and applied in Electrocardiogram auto-recognition. Based on medical requires, this paper has picked up the characteristic parameters of signals from Massachusettes Institute of Technology (database). According to Rough sets theory, the attributes are optimized and studied with BP neural network. In the end, the Electrocardiogram samples are classified with those characteristic parameters. The result shows that the right ratio goes to 90%. The experiment shows that the system has the advantages of fast computation and easy realization and the system is better than other methods in optimizing attributes and enhancing the right ratio of classification.
2002, 31(4): 429-433.
Abstract:
The uniform cavity magnetic field can be formed by Hall device. This paper presents a method to measure the wire Young's modulus by means of a magnetic induction approach is presented. Guide magnet small displacement influence is passed to change on distribution of carity magnetic field. The relationship between Hall voltage and displacement function is determined. K value is calculated. Finally, a comparetion between the measurement result values by the methods of magnetic induction and stretch is also made. The measured of Young's modulus has improved greatly under the imput-output characteristic in Hall device.
The uniform cavity magnetic field can be formed by Hall device. This paper presents a method to measure the wire Young's modulus by means of a magnetic induction approach is presented. Guide magnet small displacement influence is passed to change on distribution of carity magnetic field. The relationship between Hall voltage and displacement function is determined. K value is calculated. Finally, a comparetion between the measurement result values by the methods of magnetic induction and stretch is also made. The measured of Young's modulus has improved greatly under the imput-output characteristic in Hall device.
