ISSN 
2001 Vol. 30, No. 5
2001, 30(5): 441-444.
Abstract:
A Ka-band color-TV delivery technique is introduced, which is suited for news reports or live program. Based on the equation of image quality and its signal-to-noise ratio, the fading margin of system is calculated theoretically. System scheme and key technology are recommended. Using state-of-the-art technologies, the demonstrator with low cost isdeveloped, and its behavior is evaluated. Millimeter-wave components applied to this system are described, including oscillator, mixer, antenna and duplexer et al. This demonstrator is low cost, easy to install and convenient to use. The system communication distance exceeds 1 km with image quality of 4.5-class.
A Ka-band color-TV delivery technique is introduced, which is suited for news reports or live program. Based on the equation of image quality and its signal-to-noise ratio, the fading margin of system is calculated theoretically. System scheme and key technology are recommended. Using state-of-the-art technologies, the demonstrator with low cost isdeveloped, and its behavior is evaluated. Millimeter-wave components applied to this system are described, including oscillator, mixer, antenna and duplexer et al. This demonstrator is low cost, easy to install and convenient to use. The system communication distance exceeds 1 km with image quality of 4.5-class.
2001, 30(5): 445-448.
Abstract:
The finite-difference frequency-domain method with multifrontal algorithm is presented for two-dimensional cylinder scattering problems. The Mur's absorbing boundary conditions (ABCs) of the second order and the ABCs based on the concept of field average are applied at the terminating boundary mesh nodes. As the verification example, the scattering by an infinite cylinder of the perfect electric conductor is analyzed. CPU time is greatly reduced by using multifrontal method to solve the finite-difference equations. Numerical results demonstrate its accuracy and efficiency.
The finite-difference frequency-domain method with multifrontal algorithm is presented for two-dimensional cylinder scattering problems. The Mur's absorbing boundary conditions (ABCs) of the second order and the ABCs based on the concept of field average are applied at the terminating boundary mesh nodes. As the verification example, the scattering by an infinite cylinder of the perfect electric conductor is analyzed. CPU time is greatly reduced by using multifrontal method to solve the finite-difference equations. Numerical results demonstrate its accuracy and efficiency.
2001, 30(5): 449-453.
Abstract:
To meet the challenge of future mobile communication and integrated communication and radiolocation systems, a new spread-spectrum system with space-time modulation technology is proposed, with which the system can transmit azimuth and communication message. The transmitting scheme with 36 elements circular array antennae and the spread-spectrum receiver are designed. The performance of the bit error rate and direction-finding are analyzed. Simulation results show that the performance of the bit error rate and spectrum have no influence when the modulated signal carries azimuth message. This technology is the development of modulation theory and a new form of smart antenna.
To meet the challenge of future mobile communication and integrated communication and radiolocation systems, a new spread-spectrum system with space-time modulation technology is proposed, with which the system can transmit azimuth and communication message. The transmitting scheme with 36 elements circular array antennae and the spread-spectrum receiver are designed. The performance of the bit error rate and direction-finding are analyzed. Simulation results show that the performance of the bit error rate and spectrum have no influence when the modulated signal carries azimuth message. This technology is the development of modulation theory and a new form of smart antenna.
2001, 30(5): 454-457.
Abstract:
In this paper, a knowledge-based artificial neural network is used to model the symmetrical unilateral fin-lines. Utilizing prior knowledge for reducing complexity of input-output relationships that the Artificial Neural Network (ANN) must learn, it allows an accurate ANN model to be developed with less training data which is very advantageous when training data is expensive/time Consuming to obtain, such as with EM simulation. The neural network is electromagnetically developed with a set of training data that are produced by the finite elemont method (FDTD). which is robust both from the angle of time of computation and accuracy.
In this paper, a knowledge-based artificial neural network is used to model the symmetrical unilateral fin-lines. Utilizing prior knowledge for reducing complexity of input-output relationships that the Artificial Neural Network (ANN) must learn, it allows an accurate ANN model to be developed with less training data which is very advantageous when training data is expensive/time Consuming to obtain, such as with EM simulation. The neural network is electromagnetically developed with a set of training data that are produced by the finite elemont method (FDTD). which is robust both from the angle of time of computation and accuracy.
2001, 30(5): 458-463.
Abstract:
In this paper, the pattern variation of aperture antenna with different polarization versus the truncation size of reentry body(RB) mockup is analyzed with geometrical diffraction techniques(GDT). On the basis of analysis, truncation effect of RB mockup on antenna pattern is evaluated in elaboration with experiment, thus the minimum mockup sizes corresponding to different aperture polarization on which the antenna pattern measurement error due to truncation is neglectible is obtained.
In this paper, the pattern variation of aperture antenna with different polarization versus the truncation size of reentry body(RB) mockup is analyzed with geometrical diffraction techniques(GDT). On the basis of analysis, truncation effect of RB mockup on antenna pattern is evaluated in elaboration with experiment, thus the minimum mockup sizes corresponding to different aperture polarization on which the antenna pattern measurement error due to truncation is neglectible is obtained.
2001, 30(5): 464-467.
Abstract:
A structure design scheme for a new type virtual axis machine tool(VAMT) is proposed in this paper. The scheme utilizes a 4-dof spatial parallel mechanism as main feed mechanism, assists with a dual-direction movable worktable to realize multi-coor dinates NC machining. The VAMT enjoys many advantages over its conventional counterparts:large workspace, good dexterity, position decoupling with orientation et al. The DOF of main feed mechanism is calculated, approach for inverse displacement analysis is given, and closed equation of forward displacement analysis is derived. Anumeric example is given for illustration.
A structure design scheme for a new type virtual axis machine tool(VAMT) is proposed in this paper. The scheme utilizes a 4-dof spatial parallel mechanism as main feed mechanism, assists with a dual-direction movable worktable to realize multi-coor dinates NC machining. The VAMT enjoys many advantages over its conventional counterparts:large workspace, good dexterity, position decoupling with orientation et al. The DOF of main feed mechanism is calculated, approach for inverse displacement analysis is given, and closed equation of forward displacement analysis is derived. Anumeric example is given for illustration.
2001, 30(5): 468-471.
Abstract:
The soft and hard structure of the VI test system based on networks applying computer and network technology are described in this paper. The network realization and the distance diagnose are also discussed. The solving problems of the system realization is discussed. The soft and hard structure of the test system combines the test technology with the network. It can realize the system building in VI and meet the need of the instrument's linking each other and share the resoures. So, it makes the system function stronger.
The soft and hard structure of the VI test system based on networks applying computer and network technology are described in this paper. The network realization and the distance diagnose are also discussed. The solving problems of the system realization is discussed. The soft and hard structure of the test system combines the test technology with the network. It can realize the system building in VI and meet the need of the instrument's linking each other and share the resoures. So, it makes the system function stronger.
2001, 30(5): 472-475.
Abstract:
This paper present a new approach which uses virtual reality (VR) to design spherical mechanism. VR is a new design interface, which can provide a three dimensional design space. The new approach allows a designer to freely place geometric models of movable objects inside an environment consisting of fixed objects. The fixed objects can either act as a base for a mechanism or be potential sources of interference with the motion of the mechanism. The approach allows a designer to perform analysis of a mechanism while giving consideration to the interaction of that mechanism with its application environment.
This paper present a new approach which uses virtual reality (VR) to design spherical mechanism. VR is a new design interface, which can provide a three dimensional design space. The new approach allows a designer to freely place geometric models of movable objects inside an environment consisting of fixed objects. The fixed objects can either act as a base for a mechanism or be potential sources of interference with the motion of the mechanism. The approach allows a designer to perform analysis of a mechanism while giving consideration to the interaction of that mechanism with its application environment.
2001, 30(5): 476-479.
Abstract:
In this paper, the concept of a soft starter for a.c. motor is introduced. The technique boosting voltage with limited current is presented when the motor starts, and the design approach of soft starter is discussed. The hardware architecture of the starter is described, the block chart of interruption program for producing synchronal signal is given in details.
In this paper, the concept of a soft starter for a.c. motor is introduced. The technique boosting voltage with limited current is presented when the motor starts, and the design approach of soft starter is discussed. The hardware architecture of the starter is described, the block chart of interruption program for producing synchronal signal is given in details.
2001, 30(5): 480-483.
Abstract:
Considering the difficulties of bilinear transformation in the engineering design, the author of the paper makes it possible for the various quality index parameters of the transfer functions to automatically transform into the digital field through the known analog system, In addition, the author also establishes a one-to-one corresponding matrix relationship. It is fast, convenient, and precise. Moreover, it is easy of regulation and optimism, thus possessing a vertain value in automatic control and the processing of digital signals.
Considering the difficulties of bilinear transformation in the engineering design, the author of the paper makes it possible for the various quality index parameters of the transfer functions to automatically transform into the digital field through the known analog system, In addition, the author also establishes a one-to-one corresponding matrix relationship. It is fast, convenient, and precise. Moreover, it is easy of regulation and optimism, thus possessing a vertain value in automatic control and the processing of digital signals.
2001, 30(5): 484-488.
Abstract:
A new kind of coaxial slow wave structure for traveling wave tube is developed in this paper, which can be regarded as disk-loaded waveguide with coaxial dielectric rod winded by metal helix. By means of field matching method, the dispersion equation and coupling impedance for that kind of slow wave circuit are obtained. Numerical results show that kind of circuit can work in a broad operating bandwidth, and its coupling impedance can reach 15 ohms or so. The results presented in this paper provides basis on designing this kind of slow wave structure.
A new kind of coaxial slow wave structure for traveling wave tube is developed in this paper, which can be regarded as disk-loaded waveguide with coaxial dielectric rod winded by metal helix. By means of field matching method, the dispersion equation and coupling impedance for that kind of slow wave circuit are obtained. Numerical results show that kind of circuit can work in a broad operating bandwidth, and its coupling impedance can reach 15 ohms or so. The results presented in this paper provides basis on designing this kind of slow wave structure.
2001, 30(5): 489-493.
Abstract:
This paper analyzes the characteristic of space laser communication, and the importance and necessity of the APT system in space laser communication. The mathematical model is presented to analyze the error signal in APT system of space laser communication. Also, the influence to the tracking velocity and tracking precision of the system brought by the different size of laser beam, the relative location relationship between the laser beam and the detector, and the laser intensity distribution are discussed.
This paper analyzes the characteristic of space laser communication, and the importance and necessity of the APT system in space laser communication. The mathematical model is presented to analyze the error signal in APT system of space laser communication. Also, the influence to the tracking velocity and tracking precision of the system brought by the different size of laser beam, the relative location relationship between the laser beam and the detector, and the laser intensity distribution are discussed.
2001, 30(5): 494-496.
Abstract:
In this paper, the limitation of T-Matrix structure is analyzed. It is found that a solution by T-Matrix method can be transformed to a canonical solution when the boundary of the scatterer tends to the cylindrical form and the scatterer is illuminated by E-plane wave. The transition from T-Matrix method to canonical solution is established. It is concluded that T-Matrix is diagonal with the scatter boundary in this limit situation. This is also the limit of numerical solution.
In this paper, the limitation of T-Matrix structure is analyzed. It is found that a solution by T-Matrix method can be transformed to a canonical solution when the boundary of the scatterer tends to the cylindrical form and the scatterer is illuminated by E-plane wave. The transition from T-Matrix method to canonical solution is established. It is concluded that T-Matrix is diagonal with the scatter boundary in this limit situation. This is also the limit of numerical solution.
2001, 30(5): 497-502.
Abstract:
According to the APM specification, four types of power modes:Normal, Idle, Doze and Sleep based on the energy consumption management mechanism supported by hardware are presented. An energy consumption management module in embedded operating system to provide effective energy consumption management policies for application is also given. This paper also analyzes the energy consumption management strategies based on the energy consumption management policies of operating system to reduce the power consumption of system.
According to the APM specification, four types of power modes:Normal, Idle, Doze and Sleep based on the energy consumption management mechanism supported by hardware are presented. An energy consumption management module in embedded operating system to provide effective energy consumption management policies for application is also given. This paper also analyzes the energy consumption management strategies based on the energy consumption management policies of operating system to reduce the power consumption of system.
2001, 30(5): 503-506.
Abstract:
For the speciality of distributed real-time system and the program that is written by distrbuted real-time language DRTC++ based on the on the distributed os kernel DRTK, this paper introduces the design and theorem of DRTDebug, exposes the approach of adjusting the indeterminacy and initiates the model of information collection of real-time execution of distributed system. The model is easy and useful, and can be used in debugging of distributed real-time program directly.
For the speciality of distributed real-time system and the program that is written by distrbuted real-time language DRTC++ based on the on the distributed os kernel DRTK, this paper introduces the design and theorem of DRTDebug, exposes the approach of adjusting the indeterminacy and initiates the model of information collection of real-time execution of distributed system. The model is easy and useful, and can be used in debugging of distributed real-time program directly.
2001, 30(5): 507-510.
Abstract:
In this paper, the implementation of inter-control of multitasking on dynamic simulation environment for WindowsNT is based on processor. Controlling multitasing is accomplished by controlling its thread and the communication of major process. One task can control the executed stated of itself or other tasking with sample function call. Controlling task include suspend, resume, terminate and change of priority. The method is easy and useful.
In this paper, the implementation of inter-control of multitasking on dynamic simulation environment for WindowsNT is based on processor. Controlling multitasing is accomplished by controlling its thread and the communication of major process. One task can control the executed stated of itself or other tasking with sample function call. Controlling task include suspend, resume, terminate and change of priority. The method is easy and useful.
2001, 30(5): 511-515.
Abstract:
This paper describes a reliable and efficient data concentrating system (DCS) based on the triggers, log tables and an algorithm that can update remote data reliably. The DCS running under UNIX includes two parts:data capturing module and data sending module, respectively. The main contribution of the DCS is that it is independent of specific application, so it can gather all application's data transparently. Moreover, the DCS can detect the availability of network and remote host automatically and tolerate many unexpected defaults such as a host crashing, network breaking suddenly, etc.
This paper describes a reliable and efficient data concentrating system (DCS) based on the triggers, log tables and an algorithm that can update remote data reliably. The DCS running under UNIX includes two parts:data capturing module and data sending module, respectively. The main contribution of the DCS is that it is independent of specific application, so it can gather all application's data transparently. Moreover, the DCS can detect the availability of network and remote host automatically and tolerate many unexpected defaults such as a host crashing, network breaking suddenly, etc.
2001, 30(5): 516-519.
Abstract:
To deal with the feature extraction difficulty caused by figure stroke break or stroke fusion in image recognition, a method based on coupling end-point direction is put forward to repair the broken stroke. The following steps of image pretreatment, end-point extraction, distinguishing coupling end-point and repairing figure are illustrated taking the number plate image recognition as an application. And the results of simulation experiments are given, before-repaired and after-repaired figures are compared.
To deal with the feature extraction difficulty caused by figure stroke break or stroke fusion in image recognition, a method based on coupling end-point direction is put forward to repair the broken stroke. The following steps of image pretreatment, end-point extraction, distinguishing coupling end-point and repairing figure are illustrated taking the number plate image recognition as an application. And the results of simulation experiments are given, before-repaired and after-repaired figures are compared.
2001, 30(5): 520-524.
Abstract:
On the base of the static game model between two countries' tariff policy, this paper applyies game theory, and analyzes the reasons and conditions of founding the world trade organization.It is also illuminates that under the general tendencies of worldwide economics unification and global trade liberation, carrying out worldwide free trade in the short future is not realistic and developing regional economic cooperations is seemly relatively feasible in respect that all counties are tremendously different in aspect of economics, politics, culture, etc. and most countries' foreign economics and trade policies are influenced by domestic profit groups, more and less.
On the base of the static game model between two countries' tariff policy, this paper applyies game theory, and analyzes the reasons and conditions of founding the world trade organization.It is also illuminates that under the general tendencies of worldwide economics unification and global trade liberation, carrying out worldwide free trade in the short future is not realistic and developing regional economic cooperations is seemly relatively feasible in respect that all counties are tremendously different in aspect of economics, politics, culture, etc. and most countries' foreign economics and trade policies are influenced by domestic profit groups, more and less.
2001, 30(5): 525-528.
Abstract:
This paper studied a new set-valued quasi-variational inclusions. By using the properties of m -accretive, the equivalence between the generalized nonlinear set-valued quasi-variational inclusions, the resolvent equations, and the fixed-point problem in Banach spaces are established. Using the equivalence, some iterative algorithms for a new class of generalized nonlinear set-valued quasi-variational inclusions and related optimization problems is developed. The algorithms and results improve and generalize many known corresponding algorithms and results in resent years.
This paper studied a new set-valued quasi-variational inclusions. By using the properties of m -accretive, the equivalence between the generalized nonlinear set-valued quasi-variational inclusions, the resolvent equations, and the fixed-point problem in Banach spaces are established. Using the equivalence, some iterative algorithms for a new class of generalized nonlinear set-valued quasi-variational inclusions and related optimization problems is developed. The algorithms and results improve and generalize many known corresponding algorithms and results in resent years.
2001, 30(5): 529-532.
Abstract:
With the assumption that the initial problem of funetionao-defferential equation satisfied the solution's existence and extensibility, this paper functional-differential equation with infinite delay, builds some judge-ment theorems on uniform asymptotic stability of solutions and given a full condition on the uniform asymptotics stability of zero solution of Voterra integral-differential equation with infinite delay.
With the assumption that the initial problem of funetionao-defferential equation satisfied the solution's existence and extensibility, this paper functional-differential equation with infinite delay, builds some judge-ment theorems on uniform asymptotic stability of solutions and given a full condition on the uniform asymptotics stability of zero solution of Voterra integral-differential equation with infinite delay.
2001, 30(5): 533-537.
Abstract:
After discussing the real meaning of the problem of item-by-item repeat matchs based on the same attribution possessed, this paper gives a concept of item-by-item repeat matchs based on the same attribution in the EB environment and every cases of the match. The definition of the largest repeating matching, smellest repeating match, general match and their judge rule are also given. A exact solving algorithm is proposed. It's time complexity is analyzed. The result of the algrithm time complexity is n Sm. A improving algorithm, the complexity of which is O(C) is also easily operating by manual.
After discussing the real meaning of the problem of item-by-item repeat matchs based on the same attribution possessed, this paper gives a concept of item-by-item repeat matchs based on the same attribution in the EB environment and every cases of the match. The definition of the largest repeating matching, smellest repeating match, general match and their judge rule are also given. A exact solving algorithm is proposed. It's time complexity is analyzed. The result of the algrithm time complexity is n Sm. A improving algorithm, the complexity of which is O(C) is also easily operating by manual.
2001, 30(5): 538-541.
Abstract:
This paper formulate estimate value to the integration of functions of many variables which satisfy some condions by a simply way that converting any region to regular region whose area is equal to the gormer. This paper take some examples in order to show the approximate computation together with error analysis and numerical analysis. These are important to the appication of engineering.
This paper formulate estimate value to the integration of functions of many variables which satisfy some condions by a simply way that converting any region to regular region whose area is equal to the gormer. This paper take some examples in order to show the approximate computation together with error analysis and numerical analysis. These are important to the appication of engineering.
