ISSN 
2006 Vol. 35, No. 4
2006, 35(4): 433-436.
Abstract:
This paper discusses the coupling loss induced by pointing error of receiver for coupling space light into single mode fiber in laser satellite communication systems with optical preamplifiers. An approximate analytical expression of burst error rate induced by pointing error is derived and an optimized model for the burst error is established. Given the desired burst error rate and the pointing error of transmitter and receiver, the transmitting beam width, receiving antenna diameter and space optical coupling parameter can be optimized so as to minimize the transmitted power, the power loss induced by pointing error of receiver is also analyzed. The simulation shows that, under the optimal conditions, the power penalty induced by space optical coupling of receiver is less than 2 dB when the product of receiving antenna diameter and the rms pointing error of receiver is less than 0.15 waves.
This paper discusses the coupling loss induced by pointing error of receiver for coupling space light into single mode fiber in laser satellite communication systems with optical preamplifiers. An approximate analytical expression of burst error rate induced by pointing error is derived and an optimized model for the burst error is established. Given the desired burst error rate and the pointing error of transmitter and receiver, the transmitting beam width, receiving antenna diameter and space optical coupling parameter can be optimized so as to minimize the transmitted power, the power loss induced by pointing error of receiver is also analyzed. The simulation shows that, under the optimal conditions, the power penalty induced by space optical coupling of receiver is less than 2 dB when the product of receiving antenna diameter and the rms pointing error of receiver is less than 0.15 waves.
2006, 35(4): 437-439.
Abstract:
The key technique in optical communications is the narrow beam orientation. According to the small-angle measurement theory of laser alignment system divergence, an accuracy and high-speed measuring method using Charged Couple Device (CCD) is proposed to measure far-filed focus facula. The far-field divergence of laser alignment systems is measured experimentally. The results demonstrate that the error produced by this method is less than the maximum of International Standardization Organization.
The key technique in optical communications is the narrow beam orientation. According to the small-angle measurement theory of laser alignment system divergence, an accuracy and high-speed measuring method using Charged Couple Device (CCD) is proposed to measure far-filed focus facula. The far-field divergence of laser alignment systems is measured experimentally. The results demonstrate that the error produced by this method is less than the maximum of International Standardization Organization.
2006, 35(4): 440-442,453.
Abstract:
This paper proposes a Joint Routing Algorithm (JRA) for shared-path under Shared Risk Link Group (SRLG) constraints. JRA uses a novel K-Paths-Pairs (KPP) routing to select the minimum cost primary and SRLG-disjoint backup paths pair for each connection request. Under dynamic traffic with different load, the performances of JRA have been investigated via simulations. The results show that JRA not only can near the optimal performances but also can make the tradeoffs between the resource utilization ratio (or blocking ratio) and the protection-switching time.
This paper proposes a Joint Routing Algorithm (JRA) for shared-path under Shared Risk Link Group (SRLG) constraints. JRA uses a novel K-Paths-Pairs (KPP) routing to select the minimum cost primary and SRLG-disjoint backup paths pair for each connection request. Under dynamic traffic with different load, the performances of JRA have been investigated via simulations. The results show that JRA not only can near the optimal performances but also can make the tradeoffs between the resource utilization ratio (or blocking ratio) and the protection-switching time.
2006, 35(4): 443-446.
Abstract:
The characteristic of dispersion-managed "breathing" soliton transmission is studied with numerical methods. The achieved results indicate that the main body or the core of soliton is stable and the perturbation induced from period amplifier and dispersion management can be ignored in condition of Za (Zd) 1 <<. This proves that the dispersion managed "breathing" soliton transmission is a stable transmission scheme.
The characteristic of dispersion-managed "breathing" soliton transmission is studied with numerical methods. The achieved results indicate that the main body or the core of soliton is stable and the perturbation induced from period amplifier and dispersion management can be ignored in condition of Za (Zd) 1 <<. This proves that the dispersion managed "breathing" soliton transmission is a stable transmission scheme.
2006, 35(4): 447-449.
Abstract:
It is very slow at present to reconstruct an image from its sparse decomposition results. To overcome this one of main drawbacks in image sparse decomposition, the energy distribution property of the atoms is studied in this paper. Based on the property that energy of most atoms is very concentrated, an algorithm is proposed to fast reconstruct an image from atoms' parameters by limiting atom reconstruction calculating within the atom energy concentrating area. Moreover, methods for fast calculating atom energy and normalization are also proposed. The fast algorithm presented in this paper improves the speed of the image reconstructing by about 32 times and at the same time doesn't degrade the reconstructed image quality at all.
It is very slow at present to reconstruct an image from its sparse decomposition results. To overcome this one of main drawbacks in image sparse decomposition, the energy distribution property of the atoms is studied in this paper. Based on the property that energy of most atoms is very concentrated, an algorithm is proposed to fast reconstruct an image from atoms' parameters by limiting atom reconstruction calculating within the atom energy concentrating area. Moreover, methods for fast calculating atom energy and normalization are also proposed. The fast algorithm presented in this paper improves the speed of the image reconstructing by about 32 times and at the same time doesn't degrade the reconstructed image quality at all.
2006, 35(4): 450-453.
Abstract:
A novel face feature extraction method is presented in this paper. In this method, the raw face images are denoised by DCT, and dimension reduced features are obtained, then the KDA is performed on the feature vectors to enhance discriminant power. Finally, the NN classifier is selected to perform face classification. The experimental results on ORL face database show that the proposed method achieves an average recognition accuracy of 97.3% using only 28 features and the ‘leave one out’ recognition rate is 99.5%. Moreover, the dicriminant power is enhanced effectively, and the computing complexity and feature dimensions are reduced greatly.
A novel face feature extraction method is presented in this paper. In this method, the raw face images are denoised by DCT, and dimension reduced features are obtained, then the KDA is performed on the feature vectors to enhance discriminant power. Finally, the NN classifier is selected to perform face classification. The experimental results on ORL face database show that the proposed method achieves an average recognition accuracy of 97.3% using only 28 features and the ‘leave one out’ recognition rate is 99.5%. Moreover, the dicriminant power is enhanced effectively, and the computing complexity and feature dimensions are reduced greatly.
2006, 35(4): 454-457.
Abstract:
To overcome the problem of signal-subspace dimension expanding, three different improved methods for wideband signal-subspace spatial-spectrum estimation are presented. The first method, called the signal-subspace dimension estimation method, estimates signal-subspace dimension by a number of eigenvalues, which include 99.9% signal power; thus this method can make a correct division between signal-subspace and noise-subspace. The other two methods. weighted noise-subspace method and extended MUSIC method, do not need to make a correct division between the two subspaces. Instead. These two methods can reduce the effect of signal-subspace dimension expanding directly by using weighted eigenvectors in the noise-subspace or the entire space. Computer simulations show that all these improved methods can overcome effectively the effect of signal-subspace dimension expanding of wideband signal-subspace spatial-spectrum estimation and possess good statistical performance.
To overcome the problem of signal-subspace dimension expanding, three different improved methods for wideband signal-subspace spatial-spectrum estimation are presented. The first method, called the signal-subspace dimension estimation method, estimates signal-subspace dimension by a number of eigenvalues, which include 99.9% signal power; thus this method can make a correct division between signal-subspace and noise-subspace. The other two methods. weighted noise-subspace method and extended MUSIC method, do not need to make a correct division between the two subspaces. Instead. These two methods can reduce the effect of signal-subspace dimension expanding directly by using weighted eigenvectors in the noise-subspace or the entire space. Computer simulations show that all these improved methods can overcome effectively the effect of signal-subspace dimension expanding of wideband signal-subspace spatial-spectrum estimation and possess good statistical performance.
2006, 35(4): 458-460,477.
Abstract:
For detecting moving objects in an image sequence, the paper applies the fast fixed-point algorithm based on symmetric orthogonality to detect moving targets in real video images. The experiment shows that the proposed method can detect the movement trail and the contour of the taget and predict the moving direction of the target.
For detecting moving objects in an image sequence, the paper applies the fast fixed-point algorithm based on symmetric orthogonality to detect moving targets in real video images. The experiment shows that the proposed method can detect the movement trail and the contour of the taget and predict the moving direction of the target.
2006, 35(4): 461-463.
Abstract:
A simulated signal source system is designed for the Global Position System (GPS) based on the Field Programmable Gate Array (FPGA). FPGA, a widely used programmable chip, is employed for the design of simulated signal sources. In this work the high-resolution and stable GPS satellite signal is generated by using FPGA cooperated with a Radio Frequency (RF) module. The application results show that our design can facilitate the realization of the control of multiple frequencies and hence substantially reduce the multi-frequency exploration period and risk.
A simulated signal source system is designed for the Global Position System (GPS) based on the Field Programmable Gate Array (FPGA). FPGA, a widely used programmable chip, is employed for the design of simulated signal sources. In this work the high-resolution and stable GPS satellite signal is generated by using FPGA cooperated with a Radio Frequency (RF) module. The application results show that our design can facilitate the realization of the control of multiple frequencies and hence substantially reduce the multi-frequency exploration period and risk.
2006, 35(4): 464-467.
Abstract:
To improve the reliability and stability of FH communications, nonlinear transforms are used according to the properties of linear modulated digital signals. Based on the information included in the PSD of the transformed signals, an algorithm for detecting interferences applied to adaptive FH is proposed. The algorithm is based on Bayesian decision-making, which belongs to blind detection of signal-to-interference ratio (SIR) and signal-to-noise ratio (SNR). The simulation results show that the algorithm meets the requirements of FH communication systems.
To improve the reliability and stability of FH communications, nonlinear transforms are used according to the properties of linear modulated digital signals. Based on the information included in the PSD of the transformed signals, an algorithm for detecting interferences applied to adaptive FH is proposed. The algorithm is based on Bayesian decision-making, which belongs to blind detection of signal-to-interference ratio (SIR) and signal-to-noise ratio (SNR). The simulation results show that the algorithm meets the requirements of FH communication systems.
2006, 35(4): 468-470.
Abstract:
Based on the concept of correlation coefficient, this paper introduces an evaluation method of barrage jamming effect on ISAR. This method can reflect clearly distortion degree of the jammed target during the whole jamming process. Also, it make the evaluation of jamming effect quantify from zero to one. it has the merit of unitary. Furthermore, Two typical noise barrage jamming modes are employed in computer simulation of interference with ISAR. The result shows the method proposed is effective.
Based on the concept of correlation coefficient, this paper introduces an evaluation method of barrage jamming effect on ISAR. This method can reflect clearly distortion degree of the jammed target during the whole jamming process. Also, it make the evaluation of jamming effect quantify from zero to one. it has the merit of unitary. Furthermore, Two typical noise barrage jamming modes are employed in computer simulation of interference with ISAR. The result shows the method proposed is effective.
2006, 35(4): 471-473,523.
Abstract:
This paper discusses the theory of CIC decimation filter in digital downconversion processing technique of software radio receiver and analyzed the design technique of CIC filter Cascaded ISOP filters which process decimation filtering. The results validate that ISOP filter can effectively reduce the passband droop caused by CIC filtering with little degradation in aliasing attenuation sand that CIC decimation filter system can largely reduce narrowband FIR filter's lap.
This paper discusses the theory of CIC decimation filter in digital downconversion processing technique of software radio receiver and analyzed the design technique of CIC filter Cascaded ISOP filters which process decimation filtering. The results validate that ISOP filter can effectively reduce the passband droop caused by CIC filtering with little degradation in aliasing attenuation sand that CIC decimation filter system can largely reduce narrowband FIR filter's lap.
2006, 35(4): 474-477.
Abstract:
A modified TURBO algorithm is proposed with efficient operation. This algorithm remarkably reduces the amount of hardware of the TURBO decoder, where the scale of decoder memories can be reduced to the half memories required by conventional algorithms. Based on the modified TURBO algorithm, a new Add-Compare-Select (ACS) unit is designed. The simulation results show that the area and power consumption of proposed ACS unit are 32.7% and 26.8% of conventional ACS units, respectively.
A modified TURBO algorithm is proposed with efficient operation. This algorithm remarkably reduces the amount of hardware of the TURBO decoder, where the scale of decoder memories can be reduced to the half memories required by conventional algorithms. Based on the modified TURBO algorithm, a new Add-Compare-Select (ACS) unit is designed. The simulation results show that the area and power consumption of proposed ACS unit are 32.7% and 26.8% of conventional ACS units, respectively.
2006, 35(4): 478-480,487.
Abstract:
This paper introduces a dual-channel Doppler direction finder which combines the Doppler principle with the phase difference picking method used in the interferometer direction finder. The finder can be implemented with two independent receivers of same model for direction finding of broadband signals. On the basis of the description of fundamental principles of a dual-channel Doppler direction finder, this paper provides the computer simulation results of direction finding against FM signals and partial data from field tests. Theoretical deduction and test results both prove the simplicity and feasibility of the mentioned DF method.
This paper introduces a dual-channel Doppler direction finder which combines the Doppler principle with the phase difference picking method used in the interferometer direction finder. The finder can be implemented with two independent receivers of same model for direction finding of broadband signals. On the basis of the description of fundamental principles of a dual-channel Doppler direction finder, this paper provides the computer simulation results of direction finding against FM signals and partial data from field tests. Theoretical deduction and test results both prove the simplicity and feasibility of the mentioned DF method.
2006, 35(4): 481-483.
Abstract:
A modified TURBO algorithm is proposed with efficient operation.This algorithm remarkably reduces the amount of hardware of the TURBO decoder,where the scale of decoder memories can be reduced to the half memories required by conventional algorithms.Based on the modified TURBO algorithm,a new Add-Compare-Select (ACS) unit is designed.The simulation results show that the area and power consumption of proposed ACS unit are 32.7% and 26.8% of conventional ACS units,respectively.
A modified TURBO algorithm is proposed with efficient operation.This algorithm remarkably reduces the amount of hardware of the TURBO decoder,where the scale of decoder memories can be reduced to the half memories required by conventional algorithms.Based on the modified TURBO algorithm,a new Add-Compare-Select (ACS) unit is designed.The simulation results show that the area and power consumption of proposed ACS unit are 32.7% and 26.8% of conventional ACS units,respectively.
2006, 35(4): 484-487.
Abstract:
After analyzing the characteristics of polarimetric SAR images, the paper studies two methods of speckle reduction in polarimetric SAR images based on independent component analysis, then analyses advantages and applications of each algorithm. The experiment results show that the image edges are retained and the speckle are removed effectively with the methods of independent component analysis.
After analyzing the characteristics of polarimetric SAR images, the paper studies two methods of speckle reduction in polarimetric SAR images based on independent component analysis, then analyses advantages and applications of each algorithm. The experiment results show that the image edges are retained and the speckle are removed effectively with the methods of independent component analysis.
2006, 35(4): 488-490.
Abstract:
A kind of High Tc superconductive thin film microwave surface resistance test system around 12 GHz is described in this paper. The surface resistance of a single piece of high Tc superconductive thin film can be measured by a sapphire resonator with TE011+δ mode non-destructivity, at 77 K. By measuring the value of the resonator's quality factor, the surface resistance of testing sample can be also determined. And the influence of coupling device on calibrating physical model is also analyzed in this paper. Then testing accuracy of the system can be raised by improving coupling device. The test system is compared with former generations, and the testing accuracy is raised obviously.
A kind of High Tc superconductive thin film microwave surface resistance test system around 12 GHz is described in this paper. The surface resistance of a single piece of high Tc superconductive thin film can be measured by a sapphire resonator with TE011+δ mode non-destructivity, at 77 K. By measuring the value of the resonator's quality factor, the surface resistance of testing sample can be also determined. And the influence of coupling device on calibrating physical model is also analyzed in this paper. Then testing accuracy of the system can be raised by improving coupling device. The test system is compared with former generations, and the testing accuracy is raised obviously.
2006, 35(4): 491-493.
Abstract:
This paper studies the navigation and localization problem for formation cooperation from the view of information fusion. A novel active and passive combined scheme is proposed. The model to calculate the pseudomeasurement and the concomitant error covariance matrix is deduced for the planar circumstance. With a referenced fixity, cooperative localization can be achieved by only a piece of PPLI information.
This paper studies the navigation and localization problem for formation cooperation from the view of information fusion. A novel active and passive combined scheme is proposed. The model to calculate the pseudomeasurement and the concomitant error covariance matrix is deduced for the planar circumstance. With a referenced fixity, cooperative localization can be achieved by only a piece of PPLI information.
2006, 35(4): 494-496.
Abstract:
The paper applies the mode-matching technique to produce a abrupt transition matrix, called scattering matrix, which can be cascaded. A method for computing the resonant frequency in a complex cavity consisting of a series of waveguide sections is derived. By computer programming simulation, the cascaded scattering matrix is calculated in multi-mode cases and the characteristic parameters of a cavity, such as resonant frequency and Q-value, are obtained.
The paper applies the mode-matching technique to produce a abrupt transition matrix, called scattering matrix, which can be cascaded. A method for computing the resonant frequency in a complex cavity consisting of a series of waveguide sections is derived. By computer programming simulation, the cascaded scattering matrix is calculated in multi-mode cases and the characteristic parameters of a cavity, such as resonant frequency and Q-value, are obtained.
2006, 35(4): 497-499.
Abstract:
A coaxial slow-wave structure with corrugated inner conductor is investigated to solve the problem of the mode competition resulting from increasing power capacity of backward wave oscillator. The cold dispersion equation of TM0n mode of the structure is derived. The dispersion characters of the structure are computed numerically, analyzed and compared with that of sinusoidal cylindrical wave guide. The results show that the mode competition is much improved with the suggested new structure.
A coaxial slow-wave structure with corrugated inner conductor is investigated to solve the problem of the mode competition resulting from increasing power capacity of backward wave oscillator. The cold dispersion equation of TM0n mode of the structure is derived. The dispersion characters of the structure are computed numerically, analyzed and compared with that of sinusoidal cylindrical wave guide. The results show that the mode competition is much improved with the suggested new structure.
2006, 35(4): 500-502,506.
Abstract:
The defect structures for the tetragonal V2+ centers in LiF and AgCl are theoretically studied from the perturbation formulas of the Electron Paramagnetic Resonance (EPR) parameters for a 3d3 ion in tetragonal symmetry based on the cluster approach. The structure model proposed in this work suggests that the ligand intervening in the impurity V2+ and the next-nearest-neighbouring cation vacancy (VC) in the C4 axis is expected to suffer an off-center displacement △Z towards the former due to electrostatic repulsion. The theoretical EPR parameters based on the above defect structures show a good agreement with the observed values.
The defect structures for the tetragonal V2+ centers in LiF and AgCl are theoretically studied from the perturbation formulas of the Electron Paramagnetic Resonance (EPR) parameters for a 3d3 ion in tetragonal symmetry based on the cluster approach. The structure model proposed in this work suggests that the ligand intervening in the impurity V2+ and the next-nearest-neighbouring cation vacancy (VC) in the C4 axis is expected to suffer an off-center displacement △Z towards the former due to electrostatic repulsion. The theoretical EPR parameters based on the above defect structures show a good agreement with the observed values.
2006, 35(4): 503-506.
Abstract:
A methodology for generating high-speed pulses is discussed in this paper. In this scheme, the generation of high-speed pulses is transformed into the generation of controllable DC voltage and frequency information of pulses and into the pulse composition. The controllable DC level controls the level of high and low levels of pulses. The frequency information of pulses is generated by programmable data sequence which controls the pulse width and delay. The rising-and falling-times of pulses are adjusted through changing the charging and discharging currents of the synthesizing pulse circuit. The generated pulse is specified by the minimum pulse width:5 ns, the maximum swing:7 V, the accuracy of pulse level:0.1 V, and the rising or falling transition time:2 ns.
A methodology for generating high-speed pulses is discussed in this paper. In this scheme, the generation of high-speed pulses is transformed into the generation of controllable DC voltage and frequency information of pulses and into the pulse composition. The controllable DC level controls the level of high and low levels of pulses. The frequency information of pulses is generated by programmable data sequence which controls the pulse width and delay. The rising-and falling-times of pulses are adjusted through changing the charging and discharging currents of the synthesizing pulse circuit. The generated pulse is specified by the minimum pulse width:5 ns, the maximum swing:7 V, the accuracy of pulse level:0.1 V, and the rising or falling transition time:2 ns.
2006, 35(4): 507-509.
Abstract:
The effect of weather factors and special events on electric power load are investigated. A load forecasting model based on Radial Basis Function (RBF)is presented the temperature and precipitation are applied to RBF's training process. This optimizing algorithm can improve the credibility and reliability of network training. A practical software package has been formed and applied, which improves the precision of short-term load forecastin. The effectiveness of the model has been verified by actual operation.
The effect of weather factors and special events on electric power load are investigated. A load forecasting model based on Radial Basis Function (RBF)is presented the temperature and precipitation are applied to RBF's training process. This optimizing algorithm can improve the credibility and reliability of network training. A practical software package has been formed and applied, which improves the precision of short-term load forecastin. The effectiveness of the model has been verified by actual operation.
2006, 35(4): 510-513.
Abstract:
A continuous-time model identification method from sample data with high-frequency colored noise is presented. The method is applied to the continuous-time model identification of magnetostrictive actuator. By introducing an integral operation, the differential equations of continuous-time system can be transformed into integral equations so that the effect of the noise can be eliminated and that a continuous-time model can be estimated directly by using conventional LS methods. Simulation example demonstrates the effectiveness and the feasibility of the presented method. The identified continuous-time model of the magnetostrictive actuator has high reliability.
A continuous-time model identification method from sample data with high-frequency colored noise is presented. The method is applied to the continuous-time model identification of magnetostrictive actuator. By introducing an integral operation, the differential equations of continuous-time system can be transformed into integral equations so that the effect of the noise can be eliminated and that a continuous-time model can be estimated directly by using conventional LS methods. Simulation example demonstrates the effectiveness and the feasibility of the presented method. The identified continuous-time model of the magnetostrictive actuator has high reliability.
2006, 35(4): 514-517.
Abstract:
In development of open numerical control systems,there are numerous hardware and software in the market of the home and abroad. This paper utilizes the AHP method in the architecture mathematical modeling, the open CNC (Computer Numerical Control) system is successfully selected to meet ideal demand. This system is a PMAC-NC (Programmable Multi-axis Controller Numerical Control) system, in which numerical control machine tools is controlled by PMAC multi-axis motion controller. The system can meet the require of engineering and instruction.
In development of open numerical control systems,there are numerous hardware and software in the market of the home and abroad. This paper utilizes the AHP method in the architecture mathematical modeling, the open CNC (Computer Numerical Control) system is successfully selected to meet ideal demand. This system is a PMAC-NC (Programmable Multi-axis Controller Numerical Control) system, in which numerical control machine tools is controlled by PMAC multi-axis motion controller. The system can meet the require of engineering and instruction.
2006, 35(4): 518-520,537.
Abstract:
A scheme of real-time simulation system of supervisory for hydroelectric generating units is proposed. The compositional simulation system is constituted by digital simulation to hydroelectric generating units and its auxiliary equipment with combining the software and hardware applied in the layer of supervisory. Series of dynamic processes of supervisory to hydroelectric generating units are simulated real-time in this system.
A scheme of real-time simulation system of supervisory for hydroelectric generating units is proposed. The compositional simulation system is constituted by digital simulation to hydroelectric generating units and its auxiliary equipment with combining the software and hardware applied in the layer of supervisory. Series of dynamic processes of supervisory to hydroelectric generating units are simulated real-time in this system.
2006, 35(4): 521-523.
Abstract:
Based on the basic principle of sensors with supporter filled element that measures the methane concentration, a method for designing Weston bridge by using the sensor and the reference element is proposed and the mathematical model of the automatic temperature control and the measurement of methane concentration is developed. The measurement results show that this design expands the measuring range, reduces burning-knot and vaporization of catalyst and extends the service life of the supporter catalyst filled element.
Based on the basic principle of sensors with supporter filled element that measures the methane concentration, a method for designing Weston bridge by using the sensor and the reference element is proposed and the mathematical model of the automatic temperature control and the measurement of methane concentration is developed. The measurement results show that this design expands the measuring range, reduces burning-knot and vaporization of catalyst and extends the service life of the supporter catalyst filled element.
2006, 35(4): 524-527.
Abstract:
This paper presents a new concurrent communication mechanism, which uses object Transfer protocol, dynamic thread-pool technology and session mechanism to send and receive data. By designing a two-level blocked queue for the thread pool to delay the process of destroying thread, this mechanism can response the client request quickly, and the system resource and time consumed by creating and destroying thread can be brought down. An efficient and reliable communication service for the distributed operating system can be provided by this mechanism.
This paper presents a new concurrent communication mechanism, which uses object Transfer protocol, dynamic thread-pool technology and session mechanism to send and receive data. By designing a two-level blocked queue for the thread pool to delay the process of destroying thread, this mechanism can response the client request quickly, and the system resource and time consumed by creating and destroying thread can be brought down. An efficient and reliable communication service for the distributed operating system can be provided by this mechanism.
2006, 35(4): 528-530,566.
Abstract:
The efficiency of the generalized Paillier (G-Paillier) encryption scheme is improved by choosing proper parameters. The efficiency of the improved G-Paillier scheme and the original G-Paillier scheme is compared. The security (one-wayness security, semantic security) equivalence of the improved encryption scheme and the G-Paillier encryption scheme is verified.
The efficiency of the generalized Paillier (G-Paillier) encryption scheme is improved by choosing proper parameters. The efficiency of the improved G-Paillier scheme and the original G-Paillier scheme is compared. The security (one-wayness security, semantic security) equivalence of the improved encryption scheme and the G-Paillier encryption scheme is verified.
2006, 35(4): 531-533,541.
Abstract:
ACBM is a Boyer-Moore like algorithm applied to a set of keywords held in an Aho-Corassick like keyword tree that overlays common prefixes of the keywords. The algorithm takes the best characteristics of both the Boyer-Moore and Aho-Corasick. Based on the idea of Boyer-Moore-Horspool, we make an improvement to AC-BM algorithm. In the improved version, the Good Prefix Shift is not performed, the Bad Character Shift function is improved, the Goto procedure is also modified which do not keep the parameters of Good Prefix Shift and Bad Character Shift.
ACBM is a Boyer-Moore like algorithm applied to a set of keywords held in an Aho-Corassick like keyword tree that overlays common prefixes of the keywords. The algorithm takes the best characteristics of both the Boyer-Moore and Aho-Corasick. Based on the idea of Boyer-Moore-Horspool, we make an improvement to AC-BM algorithm. In the improved version, the Good Prefix Shift is not performed, the Bad Character Shift function is improved, the Goto procedure is also modified which do not keep the parameters of Good Prefix Shift and Bad Character Shift.
2006, 35(4): 534-537.
Abstract:
Through the analysis of classification technique of Web request, It is we found that a lot of information to classify is needed, so the realization of QoS policy is complex. In this paper, we put forward a new classification system of Web QoS based on PKI, it adopted PKI technique to reform the access security characteristic of Web server. We realized the binding between user's certificate and Qos policy with the use of Web Qos policy server. It makes the QoS policy realize easily. Therefore the demand of network user can be met better.
Through the analysis of classification technique of Web request, It is we found that a lot of information to classify is needed, so the realization of QoS policy is complex. In this paper, we put forward a new classification system of Web QoS based on PKI, it adopted PKI technique to reform the access security characteristic of Web server. We realized the binding between user's certificate and Qos policy with the use of Web Qos policy server. It makes the QoS policy realize easily. Therefore the demand of network user can be met better.
2006, 35(4): 538-541.
Abstract:
A novel algorithm based on the simulation of the major histocompatibility complex feature of human immune system is proposed. The extended negative selection algorithm makes the first decision to decide whether the network traffic is intrusion. Another algorithm, rule match-based alglrithm, makes the second decision while the first decision failed to identify the intrusion. The proposed algorithm, called major histocompatibility complex feature-based synthetic fuzzy decision-making algorithm, composes the first decision and the second decision to make a synthetic fuzzy decision by taking advantage of fuzzy logic.
A novel algorithm based on the simulation of the major histocompatibility complex feature of human immune system is proposed. The extended negative selection algorithm makes the first decision to decide whether the network traffic is intrusion. Another algorithm, rule match-based alglrithm, makes the second decision while the first decision failed to identify the intrusion. The proposed algorithm, called major histocompatibility complex feature-based synthetic fuzzy decision-making algorithm, composes the first decision and the second decision to make a synthetic fuzzy decision by taking advantage of fuzzy logic.
2006, 35(4): 542-545,563.
Abstract:
The tunnel mechanism of IPv4 WAN backbone net based on DiffServ system is a primary solution to transit IPv6 from IPv4. The QoS guarantee supplied by this tunnel mechanism is analized. The reason why DiffServ fails to realize the QoS guarantee in IPv4 WAN backbone net is given. Then the controlled acceptance mechanism that RSVP is introduced in DiffServ systems is introduced, and the service quality based on Diffserv/RSVP is studied. The result shows that the huge information of route table of nodes still has certain side effect on the QoS guarantee in Diffserv/RSVP system and that QoS is guaranteed based on Diffserv/RSVP system.
The tunnel mechanism of IPv4 WAN backbone net based on DiffServ system is a primary solution to transit IPv6 from IPv4. The QoS guarantee supplied by this tunnel mechanism is analized. The reason why DiffServ fails to realize the QoS guarantee in IPv4 WAN backbone net is given. Then the controlled acceptance mechanism that RSVP is introduced in DiffServ systems is introduced, and the service quality based on Diffserv/RSVP is studied. The result shows that the huge information of route table of nodes still has certain side effect on the QoS guarantee in Diffserv/RSVP system and that QoS is guaranteed based on Diffserv/RSVP system.
2006, 35(4): 546-549.
Abstract:
This paper presents an location-aided on-demand topology maintenance routing algorithm for Ultra-Wide Band (UWB) based ad hoc networks. The algorithm sends the packets based on the network topology and routing tables issued from location information acquired by the UWB technology. At the same time, protocol makes use of the updated location information during the route maintenance period to implement the link break repair on demand. By analyzing simulation results, this algorithm is proven in good performance, such as packet delivery ratio, average end-to-end delay and routing overhead. The feature of distributed control of the algorithm meet the requirement of dynamic ultra-wide-band ad hoc networks.
This paper presents an location-aided on-demand topology maintenance routing algorithm for Ultra-Wide Band (UWB) based ad hoc networks. The algorithm sends the packets based on the network topology and routing tables issued from location information acquired by the UWB technology. At the same time, protocol makes use of the updated location information during the route maintenance period to implement the link break repair on demand. By analyzing simulation results, this algorithm is proven in good performance, such as packet delivery ratio, average end-to-end delay and routing overhead. The feature of distributed control of the algorithm meet the requirement of dynamic ultra-wide-band ad hoc networks.
2006, 35(4): 550-553.
Abstract:
this paper presents a two-spring-two-freedom vibration system. The theoretic modal analysis and computer simulation of this system are given. Through vibration experiment, both the frequency response characteristic and modal characteristic are analyzed. The experimental method of how to test the dynamic characteristic of vibration system is also researched. The results demonstrate that the vibration experiment, computer simulation and theoretic analysis are commendably consistent.
this paper presents a two-spring-two-freedom vibration system. The theoretic modal analysis and computer simulation of this system are given. Through vibration experiment, both the frequency response characteristic and modal characteristic are analyzed. The experimental method of how to test the dynamic characteristic of vibration system is also researched. The results demonstrate that the vibration experiment, computer simulation and theoretic analysis are commendably consistent.
2006, 35(4): 554-556.
Abstract:
In this paper the periodic solution problem of high-order Functional Differential Equations (FDE) with "general" delays is studied. By changing the original equations into its equivalent FDEs and using the characteristic equation of the equivalent FDEs, the sufficient and necessary condition on which the periodic solutions of the original equations exist is presented, i.e., characteristic equation of the equivalent FDEs has nonzero imaginary solutions.
In this paper the periodic solution problem of high-order Functional Differential Equations (FDE) with "general" delays is studied. By changing the original equations into its equivalent FDEs and using the characteristic equation of the equivalent FDEs, the sufficient and necessary condition on which the periodic solutions of the original equations exist is presented, i.e., characteristic equation of the equivalent FDEs has nonzero imaginary solutions.
2006, 35(4): 557-559.
Abstract:
Pole assignment to echo feedback concerning two order distributed parameter systems is discussed. Firstly, the anti-eigenvalue problem on the closed-loop control system of second order evolution equation with echo feedback is described. In a separable and complex Hilbert space, the operator's nonzero single quadratic eigenvalue problem is transformed into the simple eigenvalue problem on the operator with perturbation. Therefore, the important result that the eigenvalue is the root of the inner product equation is obtained. The solutions of the problem and the constructive expression of the solutions are given by the operator in the constructive semi-scalar functions with the single pole.
Pole assignment to echo feedback concerning two order distributed parameter systems is discussed. Firstly, the anti-eigenvalue problem on the closed-loop control system of second order evolution equation with echo feedback is described. In a separable and complex Hilbert space, the operator's nonzero single quadratic eigenvalue problem is transformed into the simple eigenvalue problem on the operator with perturbation. Therefore, the important result that the eigenvalue is the root of the inner product equation is obtained. The solutions of the problem and the constructive expression of the solutions are given by the operator in the constructive semi-scalar functions with the single pole.
2006, 35(4): 560-563.
Abstract:
The wide-distance and wide-diameter of a graph G containing disjoint paths between two vertices of G are studied. Some characterizes of the circulant graphs with order n and degree 4 are given by symmetry of the circulant graphs. Some upper and lower bounds of wide diameter of the circulant graphs of degree 4 are also obtained. The results can be used to measure the transmission delay and fault of a class of symmetric interconnection network which is modeled as a circulant graph.
The wide-distance and wide-diameter of a graph G containing disjoint paths between two vertices of G are studied. Some characterizes of the circulant graphs with order n and degree 4 are given by symmetry of the circulant graphs. Some upper and lower bounds of wide diameter of the circulant graphs of degree 4 are also obtained. The results can be used to measure the transmission delay and fault of a class of symmetric interconnection network which is modeled as a circulant graph.
2006, 35(4): 564-566.
Abstract:
This paper studies the uniformly quasi-Lipschitzian mappings, S and T, on a bounded convex set in Banach space. S and T are defined on a bounded convex set and need not be continuous. A sufficient and necessary condition is then given and proved for Ishikawa iterative sequence with errors to converge to fixed points.
This paper studies the uniformly quasi-Lipschitzian mappings, S and T, on a bounded convex set in Banach space. S and T are defined on a bounded convex set and need not be continuous. A sufficient and necessary condition is then given and proved for Ishikawa iterative sequence with errors to converge to fixed points.
2006, 35(4): 567-569.
Abstract:
Based on the asymmetric information, this paper analyzed the price-regulation and efficiency lose of natural monopoly industry, and also compared the changing of consumer surplus and social welfare between regulation and unregulation. It drew the conclusion that even though the asymmetry caused efficiency loss of government's rules on the natural monopoly industry, the economy efficiency with government's regulation on monopoly industry is higher than that with monopoly industry.
Based on the asymmetric information, this paper analyzed the price-regulation and efficiency lose of natural monopoly industry, and also compared the changing of consumer surplus and social welfare between regulation and unregulation. It drew the conclusion that even though the asymmetry caused efficiency loss of government's rules on the natural monopoly industry, the economy efficiency with government's regulation on monopoly industry is higher than that with monopoly industry.
2006, 35(4): 570-572,576.
Abstract:
This paper analyzes the invest value of analysts' recommendations with the sample of 2 660 stocks recommended in Chinese Security Daily from 1999-07 to 2000-12. Results indicate that the recommendations of some analysts are useful to investors. According to the recommendations, four investing style and five holding term will make people win. So, analysts' recommendations embody investing value.
This paper analyzes the invest value of analysts' recommendations with the sample of 2 660 stocks recommended in Chinese Security Daily from 1999-07 to 2000-12. Results indicate that the recommendations of some analysts are useful to investors. According to the recommendations, four investing style and five holding term will make people win. So, analysts' recommendations embody investing value.
2006, 35(4): 573-576.
Abstract:
This paper examines the announcement effects of China's listed firms' divestitures completed during 1998-2002 and finds that sample firms have positive cumulative average abnormal returns in the event windows of [-1,+1] and [0,+7]. The results shows that the corporate divestitures of China can increase shareholders' wealth in a short period around the announcement date.
This paper examines the announcement effects of China's listed firms' divestitures completed during 1998-2002 and finds that sample firms have positive cumulative average abnormal returns in the event windows of [-1,+1] and [0,+7]. The results shows that the corporate divestitures of China can increase shareholders' wealth in a short period around the announcement date.
