ISSN 
2001 Vol. 30, No. 3
2001, 30(3): 221-225,235.
Abstract:
This paper analyzes the characteristic of HFC upstream channel, proposes that using SCDMA can obtain stable transmission on the condition of very low SNR. S-CDMA has an ability to resist many kind of narrow-band interference and noises, but the multi-access interference induces the capacity and performance of the system. After analyzing several multiuser detectors, this paper uses decorrelating decision-feedback detector in HFC upstream channel S-CDMA system. It can cancel the interference of the stronger users and make advantages to the decision of the weaker users, thus can cancel the multiaccess interference and has better near-far resistance. Its complexity is linear in the number of users. The system need not accurate synchronization control, thus is simplified.
This paper analyzes the characteristic of HFC upstream channel, proposes that using SCDMA can obtain stable transmission on the condition of very low SNR. S-CDMA has an ability to resist many kind of narrow-band interference and noises, but the multi-access interference induces the capacity and performance of the system. After analyzing several multiuser detectors, this paper uses decorrelating decision-feedback detector in HFC upstream channel S-CDMA system. It can cancel the interference of the stronger users and make advantages to the decision of the weaker users, thus can cancel the multiaccess interference and has better near-far resistance. Its complexity is linear in the number of users. The system need not accurate synchronization control, thus is simplified.
2001, 30(3): 226-230.
Abstract:
This paper analyzes the enhancement of the system capacity in TD-SCDMA with ideal power control using smart antenna. The interference from both the self-cell users and the neighbor cells is taken into account. When different beam width of the smart antenna is adopted, the TD-SCDMA system is simulated, and the results of the simulation prove that the system capacity can be greatly improved since the smart antenna is adopted.
This paper analyzes the enhancement of the system capacity in TD-SCDMA with ideal power control using smart antenna. The interference from both the self-cell users and the neighbor cells is taken into account. When different beam width of the smart antenna is adopted, the TD-SCDMA system is simulated, and the results of the simulation prove that the system capacity can be greatly improved since the smart antenna is adopted.
2001, 30(3): 231-235.
Abstract:
On the basis of analysis on TURBO input quantification, this paper offers the electrocircuits and iteration electro-circuits for TURBO coding in the 3GPP, with existing MAP algorithm combined, thus improves the transmission rate of the 3GPP. The recently proposed TURBO codes are applied to multilevel modulation, then to multistage decoding. Based on the information theory, the method of designing rates and interleaving lengths of TURBO codes is proposed, which makes the lower levels codes have higher correct error capacities and the higher levels codes have higher transmission capacities. The coding of TURBO codes in the 3GPP is also analyzed and the delay problem and the scale problem of FPGA are discussed. The electro-circuit performs well in coding, which meets the gain demands of the 3GPP.
On the basis of analysis on TURBO input quantification, this paper offers the electrocircuits and iteration electro-circuits for TURBO coding in the 3GPP, with existing MAP algorithm combined, thus improves the transmission rate of the 3GPP. The recently proposed TURBO codes are applied to multilevel modulation, then to multistage decoding. Based on the information theory, the method of designing rates and interleaving lengths of TURBO codes is proposed, which makes the lower levels codes have higher correct error capacities and the higher levels codes have higher transmission capacities. The coding of TURBO codes in the 3GPP is also analyzed and the delay problem and the scale problem of FPGA are discussed. The electro-circuit performs well in coding, which meets the gain demands of the 3GPP.
2001, 30(3): 236-240,249.
Abstract:
A new approach for resolving occlusion problem in augmented reality is presented in this paper. The heart of this algorithm is to track at least four fiducial points from frame to frame that construct the affine frame, thus the occlusion contours between virtual and real objects can be reconstructed and reprojected. Further, each contour is labeled as being "behind" or "in front of" in the first two frames, depending on whether it is in front of or behind the virtual object, so the occlusion is resolved. Two typical examples show that the algorithm is feasible for resolving occlusion.
A new approach for resolving occlusion problem in augmented reality is presented in this paper. The heart of this algorithm is to track at least four fiducial points from frame to frame that construct the affine frame, thus the occlusion contours between virtual and real objects can be reconstructed and reprojected. Further, each contour is labeled as being "behind" or "in front of" in the first two frames, depending on whether it is in front of or behind the virtual object, so the occlusion is resolved. Two typical examples show that the algorithm is feasible for resolving occlusion.
2001, 30(3): 241-244.
Abstract:
In this paper, a developed T-matrix method (Extended T-Matrix Method) based on elliptic cylindrical wave function is proposed for two-dimensional scattering problems. Computation results show that the method is well applied in large aspect ratio scattering problems.
In this paper, a developed T-matrix method (Extended T-Matrix Method) based on elliptic cylindrical wave function is proposed for two-dimensional scattering problems. Computation results show that the method is well applied in large aspect ratio scattering problems.
2001, 30(3): 245-249.
Abstract:
The prediction of electromagnetic interference between the electronic equipments of a large information system is a complex problem. Furthermore, the prediction of the effect of interference on electromagnetic compatibility of the system is a random process, which causes much difficulty on practical application. Based on the results of electromagnetic interference analysis, three methods of evaluating the electromagnetic compatibility are presented. Evaluation model on certain electromagnetic environment is also discussed in this paper.
The prediction of electromagnetic interference between the electronic equipments of a large information system is a complex problem. Furthermore, the prediction of the effect of interference on electromagnetic compatibility of the system is a random process, which causes much difficulty on practical application. Based on the results of electromagnetic interference analysis, three methods of evaluating the electromagnetic compatibility are presented. Evaluation model on certain electromagnetic environment is also discussed in this paper.
2001, 30(3): 250-253.
Abstract:
In this paper, neglecting amplified spontaneous emission(ASE) and upconversion process, the rate equation for Erbium-Doped Waveguide amplifiers (EDWA's) pumped with 980 nm wavelength is studied using overlapping factors method, and an analytical implicit gain solution is derived. Based on which an analytical threshold expression of pumping power is also obtained. Effects of overlapping factors on the gain and pumping threshold power are discussed in detail.
In this paper, neglecting amplified spontaneous emission(ASE) and upconversion process, the rate equation for Erbium-Doped Waveguide amplifiers (EDWA's) pumped with 980 nm wavelength is studied using overlapping factors method, and an analytical implicit gain solution is derived. Based on which an analytical threshold expression of pumping power is also obtained. Effects of overlapping factors on the gain and pumping threshold power are discussed in detail.
2001, 30(3): 254-258.
Abstract:
A new method based on GIS technology is introduced for telephone network distributing in this paper. According to coding principles, the network resources are coded to be processed in computer. The data structure and logic relationship of four main network resources are given. The hardware and software platform of whole automatic distributing system are designed in detail. In final, the automatic distributing flow on e-Map is generalized.
A new method based on GIS technology is introduced for telephone network distributing in this paper. According to coding principles, the network resources are coded to be processed in computer. The data structure and logic relationship of four main network resources are given. The hardware and software platform of whole automatic distributing system are designed in detail. In final, the automatic distributing flow on e-Map is generalized.
2001, 30(3): 259-262.
Abstract:
The special purpose power supply for shunt by transforming uniphase into triphase is an important equipment for accelerating railway speed. To ensure reliable work of the shunt and the safety of the train, this paper offers a test and control system of the special purpose power supply for shunt. The hardware architecture and various functions of the test and control system of the special purpose power supply for shunt are introduced. The work principle of voltage regulator and the design scheme of software are also expounded. Practical test verifies the validity of this test and control system in improving the performance and the reliability of the power supply for shunt.
The special purpose power supply for shunt by transforming uniphase into triphase is an important equipment for accelerating railway speed. To ensure reliable work of the shunt and the safety of the train, this paper offers a test and control system of the special purpose power supply for shunt. The hardware architecture and various functions of the test and control system of the special purpose power supply for shunt are introduced. The work principle of voltage regulator and the design scheme of software are also expounded. Practical test verifies the validity of this test and control system in improving the performance and the reliability of the power supply for shunt.
2001, 30(3): 263-266.
Abstract:
In this paper, a simple 3-bus power system model which includes a dynamic induction motor model is simulated to study chaotic characteristics. Given a deterministic model describing a system and an initial condition, the system behavior can not always be predicted. Sensitivity on initial condition, inherent randomization and so on are the characteristics of chaos. It is shown that voltage collapse can be resulted from bifurcation and chaos phenomena that a system may experience under the influence of system parameters. The result also shows voltage collapse in the chaotic area far from the saddle node bifurcation.
In this paper, a simple 3-bus power system model which includes a dynamic induction motor model is simulated to study chaotic characteristics. Given a deterministic model describing a system and an initial condition, the system behavior can not always be predicted. Sensitivity on initial condition, inherent randomization and so on are the characteristics of chaos. It is shown that voltage collapse can be resulted from bifurcation and chaos phenomena that a system may experience under the influence of system parameters. The result also shows voltage collapse in the chaotic area far from the saddle node bifurcation.
2001, 30(3): 267-270.
Abstract:
An algorithm of computing the average frequency of motor vehicle brake oil pressure is expounded, by which the increase of oil pressure, steady and reductive frequency in a moment of a motor vehicle braking is also given. Its elemental model, calculating subroutine, structure flow chart and error value are proposed. The algorithm can avoid the incorrect judgement resulted from one or two abnormality datum and there is a high veracity of the test datum.
An algorithm of computing the average frequency of motor vehicle brake oil pressure is expounded, by which the increase of oil pressure, steady and reductive frequency in a moment of a motor vehicle braking is also given. Its elemental model, calculating subroutine, structure flow chart and error value are proposed. The algorithm can avoid the incorrect judgement resulted from one or two abnormality datum and there is a high veracity of the test datum.
2001, 30(3): 271-274.
Abstract:
To the control problems in the biology processing system of integrated oxidation ditch, the DCS system practical scheme that consists of practical, field bus based ADAM-5000/CAN series and IPC is presented to sewage treatment at some factory. The scheme that adoptes ADAM-5000/CAN in the field has the characteristics of multi-master structure, real-time capability and high reliability communication. Besides the IPC that integrates monitor with control has rich resource, thus the DCS system possesses reliable open system architecture, quality real-time capability, high reliability and expedient operability.
To the control problems in the biology processing system of integrated oxidation ditch, the DCS system practical scheme that consists of practical, field bus based ADAM-5000/CAN series and IPC is presented to sewage treatment at some factory. The scheme that adoptes ADAM-5000/CAN in the field has the characteristics of multi-master structure, real-time capability and high reliability communication. Besides the IPC that integrates monitor with control has rich resource, thus the DCS system possesses reliable open system architecture, quality real-time capability, high reliability and expedient operability.
2001, 30(3): 275-279.
Abstract:
In this paper, the background, main technology and the benefit of active network are reviewed. The active node model is mainly focused and a ping program which is based on the active network encapsulation protocol specification and the active node transfer system tool is developed to introduce active network technology. In the end, the improved method of security, performance and interoperability is put forward and its vole in the programming network is discussed.
In this paper, the background, main technology and the benefit of active network are reviewed. The active node model is mainly focused and a ping program which is based on the active network encapsulation protocol specification and the active node transfer system tool is developed to introduce active network technology. In the end, the improved method of security, performance and interoperability is put forward and its vole in the programming network is discussed.
2001, 30(3): 280-283,291.
Abstract:
Synchronized multimedia integration language(SMIL) is an important application of the new generation web language--XML, and can synchronize variant media, save network bandwidth and support super-link. The development and integration system of network-multimedia courseware is a tool of creating and editing network teaching courseware that is based on synchronized multimedia integration language(SMIL). It takes the advantage of SMIL's good on creating network multimedia, and introduces modeling conception, which provides teachers and students a function-strong and using-simple network distance education environment. It has a lot of advantages of saving bandwidth and synchronizing easily as well.
Synchronized multimedia integration language(SMIL) is an important application of the new generation web language--XML, and can synchronize variant media, save network bandwidth and support super-link. The development and integration system of network-multimedia courseware is a tool of creating and editing network teaching courseware that is based on synchronized multimedia integration language(SMIL). It takes the advantage of SMIL's good on creating network multimedia, and introduces modeling conception, which provides teachers and students a function-strong and using-simple network distance education environment. It has a lot of advantages of saving bandwidth and synchronizing easily as well.
2001, 30(3): 284-286.
Abstract:
In this paper, the hardware design of the MUX is introduced, which centralizes 3 synchronous/5 asynchronous or 8 asynchronous data on a single channel. With the internal master serial port and external master serial port connecting to communication equipment, the data multiplex is implemented, which is able to keep working by swithing automaticly to reserve line when the current line fails to work normally. It also makes the communication more secure by encrypting the data issued at the port and the communication line. This paper also studies the interrupt system, data communication control, system reliability design.
In this paper, the hardware design of the MUX is introduced, which centralizes 3 synchronous/5 asynchronous or 8 asynchronous data on a single channel. With the internal master serial port and external master serial port connecting to communication equipment, the data multiplex is implemented, which is able to keep working by swithing automaticly to reserve line when the current line fails to work normally. It also makes the communication more secure by encrypting the data issued at the port and the communication line. This paper also studies the interrupt system, data communication control, system reliability design.
2001, 30(3): 287-291.
Abstract:
The concept and extracting method of the effective-rows feature, which possesses low dimension, shift-invariance and rotation-invariance under little angle is proposed on the basis of the structure of unconstraint and handwritten numerals in this paper. Its features is also constructed. According to the result of widely verifying recognition BP network, it is demonstrated that its recognitionspeed is superior to the traditional recognition methods only based on the feature of moment or wavelet and its recognition-extract is higher than some conventional methods.
The concept and extracting method of the effective-rows feature, which possesses low dimension, shift-invariance and rotation-invariance under little angle is proposed on the basis of the structure of unconstraint and handwritten numerals in this paper. Its features is also constructed. According to the result of widely verifying recognition BP network, it is demonstrated that its recognitionspeed is superior to the traditional recognition methods only based on the feature of moment or wavelet and its recognition-extract is higher than some conventional methods.
2001, 30(3): 292-294.
Abstract:
In this paper, a framwork and mechanism of making up VPN between SOCKS fire walls in Internet are proposed. Their identification are implemented using certificate verify supported by x.509 and digital signing, which are the authentication method extension to SOCKS V5 protocol. TLS protocol is also applied to the implement negotiation of their encryption algorithms and cryptographic keys which are used as data encryption and transmission. As well as some relative key techniques are introduced, a strong security system is shown by integrating the advantages of two protocols in this paper.
In this paper, a framwork and mechanism of making up VPN between SOCKS fire walls in Internet are proposed. Their identification are implemented using certificate verify supported by x.509 and digital signing, which are the authentication method extension to SOCKS V5 protocol. TLS protocol is also applied to the implement negotiation of their encryption algorithms and cryptographic keys which are used as data encryption and transmission. As well as some relative key techniques are introduced, a strong security system is shown by integrating the advantages of two protocols in this paper.
2001, 30(3): 295-299.
Abstract:
Based on the meaning presented by transmissive indirect economic effect and obtainable indirect economic effect, the drive effect and the propel effect of each department on national economy are studied, and a classification index which classifies the effect of each department of national economy into variant types is given. According to the data of input-output of the Sichuan province from the year 1987 to 1997, the variation of the drive effect and propel effect of each department on Sichuan national economy for ten years are analyzed quantitatively. It is found that the type of each departmental effect is not constant, but various with the development of economy.
Based on the meaning presented by transmissive indirect economic effect and obtainable indirect economic effect, the drive effect and the propel effect of each department on national economy are studied, and a classification index which classifies the effect of each department of national economy into variant types is given. According to the data of input-output of the Sichuan province from the year 1987 to 1997, the variation of the drive effect and propel effect of each department on Sichuan national economy for ten years are analyzed quantitatively. It is found that the type of each departmental effect is not constant, but various with the development of economy.
2001, 30(3): 300-303.
Abstract:
This paper studies the pattern of autocorrelation of stock returns in Shanghai stock market, assuming that some investors follow a positive feedback trading strategy. The sample is the daily returns from September 29 of 1992 to September 30 of 1997. In addition, GARCH(1,1) model is adopted to deal with heteroskedastic property of return volatility, and the maximum likelihood method is used to estimate the model parameters. The positive serial correlation caused by nonsynchronous trading and nonsymmetry of feedback trading are also considered in the model. The empirical results show that in addition to positive serial correlation described in previous literature, there is a strong evidence that positice feedback trading induces negative autocrrelation in index stock returns, which in absolute terms increases with volatility. Thus the autocorrelation of index stock returns and volatility are related.
This paper studies the pattern of autocorrelation of stock returns in Shanghai stock market, assuming that some investors follow a positive feedback trading strategy. The sample is the daily returns from September 29 of 1992 to September 30 of 1997. In addition, GARCH(1,1) model is adopted to deal with heteroskedastic property of return volatility, and the maximum likelihood method is used to estimate the model parameters. The positive serial correlation caused by nonsynchronous trading and nonsymmetry of feedback trading are also considered in the model. The empirical results show that in addition to positive serial correlation described in previous literature, there is a strong evidence that positice feedback trading induces negative autocrrelation in index stock returns, which in absolute terms increases with volatility. Thus the autocorrelation of index stock returns and volatility are related.
2001, 30(3): 304-307.
Abstract:
This paper estabilishes the superior model on the foreign investment of the infrastructure and makes a qualitative game analysis on the scales for the infrastructure investment both home and abroad. Based on that, this paper makes a further study on the causes of the present policy background. The relative qualitative analysis is also made. It is concluded that the investment on the infrastructure from foreigners is far beyond expected and some suggestions on how to attract foreign investment to the West are made to provide a reference for the policy makers.
This paper estabilishes the superior model on the foreign investment of the infrastructure and makes a qualitative game analysis on the scales for the infrastructure investment both home and abroad. Based on that, this paper makes a further study on the causes of the present policy background. The relative qualitative analysis is also made. It is concluded that the investment on the infrastructure from foreigners is far beyond expected and some suggestions on how to attract foreign investment to the West are made to provide a reference for the policy makers.
2001, 30(3): 308-312.
Abstract:
In this paper, the conclusion under linear demand drawn from Cournot model and Stackelberg model is reviewed. The difference between two conditions of linear demand and nonlinear demand are discussed. It is concluded that the choose of the first-mover advantage or the second-mover advantage under linear demand is based on the price elasticity of demand.
In this paper, the conclusion under linear demand drawn from Cournot model and Stackelberg model is reviewed. The difference between two conditions of linear demand and nonlinear demand are discussed. It is concluded that the choose of the first-mover advantage or the second-mover advantage under linear demand is based on the price elasticity of demand.
2001, 30(3): 313-315.
Abstract:
By using linear transformation method, this paper gives the necessary and sufficient conditions for Lyapunov equation. The unique solutions are obtained. The method in this paper is elementary and the results are richer than those in references. The method can also be used to deal with matrix equations on general field, which supplies a new method to cryptography.
By using linear transformation method, this paper gives the necessary and sufficient conditions for Lyapunov equation. The unique solutions are obtained. The method in this paper is elementary and the results are richer than those in references. The method can also be used to deal with matrix equations on general field, which supplies a new method to cryptography.
2001, 30(3): 316-319.
Abstract:
In this paper, a gradient projection algorithm using maxim-entropy methods is analyzed and a class of max-min problems with nonlinear constraints are changed into nonlinear programming problems with inequality and equality constra. The algorithm which resolves general max-min problems is global convergent. Preliminary numerical experiments show that the proposed algorithm is effective.
In this paper, a gradient projection algorithm using maxim-entropy methods is analyzed and a class of max-min problems with nonlinear constraints are changed into nonlinear programming problems with inequality and equality constra. The algorithm which resolves general max-min problems is global convergent. Preliminary numerical experiments show that the proposed algorithm is effective.
2001, 30(3): 320-324.
Abstract:
This paper analyzes the current situations of the western china. Based on the western status in national economy and its conditions, this paper also points out that personal training and technical commercializing are the source of the western development in the era of intellectual economy. Currently, at the oppotune moment of the western development, colleges and university of higher learning should take advantage of their qualified personnel, intellectual and technique superiority to found the western personal training base and serve as a connection of enterprises and schools, which will help to accelerate the western personal training and hi-tech achievement commercializing, and supply ample qualified personnel, intellectual and technique for the western development.
This paper analyzes the current situations of the western china. Based on the western status in national economy and its conditions, this paper also points out that personal training and technical commercializing are the source of the western development in the era of intellectual economy. Currently, at the oppotune moment of the western development, colleges and university of higher learning should take advantage of their qualified personnel, intellectual and technique superiority to found the western personal training base and serve as a connection of enterprises and schools, which will help to accelerate the western personal training and hi-tech achievement commercializing, and supply ample qualified personnel, intellectual and technique for the western development.
