ISSN 
2006 Vol. 35, No. 5
2006, 35(5): 717-720.
Abstract:
Routing algorithms of satellite communication system with hybrid orbit are studied. The system consists of LEO and GEO satellites. "The longest covered-time" and "the shortest path" routing algorithms are proposed, which are analyzed and simulated. Route reconstructed rate and datagram loss rate are compared for the two algorithms. The results indicate that "the longest covered-time" routing algorithm can improve the system performance compared with "the shortest path" one.
Routing algorithms of satellite communication system with hybrid orbit are studied. The system consists of LEO and GEO satellites. "The longest covered-time" and "the shortest path" routing algorithms are proposed, which are analyzed and simulated. Route reconstructed rate and datagram loss rate are compared for the two algorithms. The results indicate that "the longest covered-time" routing algorithm can improve the system performance compared with "the shortest path" one.
2006, 35(5): 721-724.
Abstract:
A dynamic channel reserve strategy for LEO communication system with spot-beam is proposed. It does not need to record the location of the mobiles. Using the characteristic of mobile, we proposed a way to predict the number of channels those should be reserved in a spot-beam by the distribution of subscribers between spot-beams. The comparison between our strategy and the fixed channel reserve strategy through simulation shows that the former can automatically adjust the number of reserve channels, and improve the performance of the system.
A dynamic channel reserve strategy for LEO communication system with spot-beam is proposed. It does not need to record the location of the mobiles. Using the characteristic of mobile, we proposed a way to predict the number of channels those should be reserved in a spot-beam by the distribution of subscribers between spot-beams. The comparison between our strategy and the fixed channel reserve strategy through simulation shows that the former can automatically adjust the number of reserve channels, and improve the performance of the system.
2006, 35(5): 725-728.
Abstract:
A regional satellite navigation system which is made up of geosynchronous satellites and synchronous satellites with elliptical orbit is proposed. The parameter of the constellation is optimized with the goal that the GDOP should be minimum.The performance of the constellation which is compared with GPS is obtained by simulation.The simulation shows this scheme can meet the requirements in china and its neighboring area.
A regional satellite navigation system which is made up of geosynchronous satellites and synchronous satellites with elliptical orbit is proposed. The parameter of the constellation is optimized with the goal that the GDOP should be minimum.The performance of the constellation which is compared with GPS is obtained by simulation.The simulation shows this scheme can meet the requirements in china and its neighboring area.
2006, 35(5): 729-732.
Abstract:
This paper introduces a new kind of node, namely, RPR-X node, to interconnect multiple Resilient Packet Rings (RPR). To achieve packets cross transmission among RPR sub-networks, and at the same time to guarantee the cross forwarding algorithm to be compatible with the standard forwarding procedure, this paper presents the extended definitions of standard RPR frame, MAC layer reference model of RPR-X node, and the corresponding packet cross forwarding algorithm. Simulation results demonstrate that the proposed method performs well in terms of performance metrics such as network's throughput and end-to-end delay.
This paper introduces a new kind of node, namely, RPR-X node, to interconnect multiple Resilient Packet Rings (RPR). To achieve packets cross transmission among RPR sub-networks, and at the same time to guarantee the cross forwarding algorithm to be compatible with the standard forwarding procedure, this paper presents the extended definitions of standard RPR frame, MAC layer reference model of RPR-X node, and the corresponding packet cross forwarding algorithm. Simulation results demonstrate that the proposed method performs well in terms of performance metrics such as network's throughput and end-to-end delay.
2006, 35(5): 733-735,773.
Abstract:
This paper proposes an active network by using adaptive Forward Error Correction (FEC) strategy which is hop-to-hop for improving transmission performance in Ad hoc networks. Fixed FEC can't perform well while wireless link is characterized by high and variable BER (Bit Error Rate). The performance of this strategy is analyzed via simulation experiments by using the Gilbert model as a wireless error model. Finally we demonstrate our method achieves better performance than fixed FEC.
This paper proposes an active network by using adaptive Forward Error Correction (FEC) strategy which is hop-to-hop for improving transmission performance in Ad hoc networks. Fixed FEC can't perform well while wireless link is characterized by high and variable BER (Bit Error Rate). The performance of this strategy is analyzed via simulation experiments by using the Gilbert model as a wireless error model. Finally we demonstrate our method achieves better performance than fixed FEC.
2006, 35(5): 736-739.
Abstract:
The characteristics of different access techniques used in optical network are analyzed and compared. A new optical network with Wavelength Division Multiplexing and Optical Code Division Multiplexing Access (WDM/OCDMA) is presented. The advantages and applications of this network scheme are discussed. In the end, the network structure of this WDM/OCDMA network and the optical CDMA encoding and decoding schema are introduced. The results show that the WDM/OCDMA network, which can fully use the advantages of WDM and OCDMA technologies, is valuable in practice.
The characteristics of different access techniques used in optical network are analyzed and compared. A new optical network with Wavelength Division Multiplexing and Optical Code Division Multiplexing Access (WDM/OCDMA) is presented. The advantages and applications of this network scheme are discussed. In the end, the network structure of this WDM/OCDMA network and the optical CDMA encoding and decoding schema are introduced. The results show that the WDM/OCDMA network, which can fully use the advantages of WDM and OCDMA technologies, is valuable in practice.
2006, 35(5): 740-743.
Abstract:
A Joint Optimal Adaptive Protection Algorithm(JOA) is proposed to establish dependable connections for dynamic arriving connection requests in WDM networks. JOA first adjusts the cost of links according to the current state of network adaptively, and it then computes a pair of primary path and backup path for each connection request simultaneously. JOA attempts to perform optimization on the path-pair selection, and to achieve efficient resource utilization. Based on dynamic traffic with different load, the performance of JOA has been investigated against some traditional approaches via simulations. The results show that JOA has a better performance than other schemes.
A Joint Optimal Adaptive Protection Algorithm(JOA) is proposed to establish dependable connections for dynamic arriving connection requests in WDM networks. JOA first adjusts the cost of links according to the current state of network adaptively, and it then computes a pair of primary path and backup path for each connection request simultaneously. JOA attempts to perform optimization on the path-pair selection, and to achieve efficient resource utilization. Based on dynamic traffic with different load, the performance of JOA has been investigated against some traditional approaches via simulations. The results show that JOA has a better performance than other schemes.
2006, 35(5): 744-747.
Abstract:
The most problems of multi-constrained QoS routing are NP-completeness. In this paper, a novel genetic algorithm is given which is applied to QoS routing. The principle of hop-prior is presented to generate an initial population. Simultaneously, two operators of vicinity crossover and forward mutation are brought forward. The primary advantages of this algorithm are shown as below:the population initialization is independent on the metrics in a network, the new personals born of crossover are diversified, and mutation depresses the algorithm devolutions effectively. At last, the simulations on differ-scale networks randomly created demonstrate that this algorithm is effective.
The most problems of multi-constrained QoS routing are NP-completeness. In this paper, a novel genetic algorithm is given which is applied to QoS routing. The principle of hop-prior is presented to generate an initial population. Simultaneously, two operators of vicinity crossover and forward mutation are brought forward. The primary advantages of this algorithm are shown as below:the population initialization is independent on the metrics in a network, the new personals born of crossover are diversified, and mutation depresses the algorithm devolutions effectively. At last, the simulations on differ-scale networks randomly created demonstrate that this algorithm is effective.
2006, 35(5): 748-751.
Abstract:
In this paper, we propose a broadband MISO/OFDM transmission system with adaptive bit and power allocation. The model of proposed system is established. The performance of maximal SNR on each sub-carrier of proposed system is analyzed. The simulation results show that the proposed system can achieve better performance compared with that of the conventional adaptive transmit diversity based OFDM systems without adaptive bit and power allocation over multipath fading channels.
In this paper, we propose a broadband MISO/OFDM transmission system with adaptive bit and power allocation. The model of proposed system is established. The performance of maximal SNR on each sub-carrier of proposed system is analyzed. The simulation results show that the proposed system can achieve better performance compared with that of the conventional adaptive transmit diversity based OFDM systems without adaptive bit and power allocation over multipath fading channels.
2006, 35(5): 752-754.
Abstract:
This paper introduces subspace methods of blind channel estimation in OFDM and its research state. The performance of the algorithm is simulated according to the symbol format of WLAN 802.11a in the exiting of virtual carriers and pilot carriers. The results show that the pilot influences convergence of the algorithm. By adding uncorrelated pilots, the convergence of the algorithm is achieve. In order to achieve a certain precision, the proper packet length and channel SNR is necessary.
This paper introduces subspace methods of blind channel estimation in OFDM and its research state. The performance of the algorithm is simulated according to the symbol format of WLAN 802.11a in the exiting of virtual carriers and pilot carriers. The results show that the pilot influences convergence of the algorithm. By adding uncorrelated pilots, the convergence of the algorithm is achieve. In order to achieve a certain precision, the proper packet length and channel SNR is necessary.
2006, 35(5): 755-758.
Abstract:
The channel distortion and error propagation of damaged macroblock are analyzed. The impact of macroblock modes on source distortion and channel distortion is discussed,and thus a fast macroblock mode selection algorithm is proposed based on joint source-channel rate distortion optimization. By evaluating the channel distortion and source distortion of all macroblock modes, the optimal macroblock mode is selected adaptively to minimize transmission distortion. Compared with the mode selection algorithm in H.264 reference software, our simulation results show that the proposed algorithm reduces computational complexity significantly and gets better error resilient.
The channel distortion and error propagation of damaged macroblock are analyzed. The impact of macroblock modes on source distortion and channel distortion is discussed,and thus a fast macroblock mode selection algorithm is proposed based on joint source-channel rate distortion optimization. By evaluating the channel distortion and source distortion of all macroblock modes, the optimal macroblock mode is selected adaptively to minimize transmission distortion. Compared with the mode selection algorithm in H.264 reference software, our simulation results show that the proposed algorithm reduces computational complexity significantly and gets better error resilient.
2006, 35(5): 759-762.
Abstract:
For the lower cost and power consumption, STN-LCD has been widely used in low and mid-end mobile applications. Based on the mathematical description, a multiple line addressing scheme is approved. We built a mathematical model that can be synthesized by EDA tools for hardware. Combined with the FRC-PWM solution of grey shading, the model is validated by FPGA. As a result, the circuit is optimized for guaranteeing the display quality of CSTN-LCD.
For the lower cost and power consumption, STN-LCD has been widely used in low and mid-end mobile applications. Based on the mathematical description, a multiple line addressing scheme is approved. We built a mathematical model that can be synthesized by EDA tools for hardware. Combined with the FRC-PWM solution of grey shading, the model is validated by FPGA. As a result, the circuit is optimized for guaranteeing the display quality of CSTN-LCD.
2006, 35(5): 763-766.
Abstract:
The array error model of joint frequency, two-Dimensional Angles of Arrival (2-D AOA) and polarization estimation is constructed. The paper then analyzes the parameter estimation performance of the algorithm based on theoretical conditions under array error and deduces the Mean-Square Error (MSE) of frequency, 2-D AOA and the polarizations. From the computer simulation we can see that the theoretical results and the simulation are similar.
The array error model of joint frequency, two-Dimensional Angles of Arrival (2-D AOA) and polarization estimation is constructed. The paper then analyzes the parameter estimation performance of the algorithm based on theoretical conditions under array error and deduces the Mean-Square Error (MSE) of frequency, 2-D AOA and the polarizations. From the computer simulation we can see that the theoretical results and the simulation are similar.
2006, 35(5): 767-769,787.
Abstract:
After analyzing the distribution mechanisms of uniform distribution and Cauchy distribution, an algorithm of blind image restoration by simulated annealing based on Cauchy distribution random perturbation is proposed. Simulation results show that the improved method has better quality, robustness and speed of convergence comparing with simulated annealing algorithm based on uniform distribution random perturbation.
After analyzing the distribution mechanisms of uniform distribution and Cauchy distribution, an algorithm of blind image restoration by simulated annealing based on Cauchy distribution random perturbation is proposed. Simulation results show that the improved method has better quality, robustness and speed of convergence comparing with simulated annealing algorithm based on uniform distribution random perturbation.
2006, 35(5): 770-773.
Abstract:
Under the analysis of LSB arithmetic in frequency domain, this paper presents the situations for enhancing robustness of LSB arithmetic and two definitions for LSB in frequency domain. Based on the first definition, this paper constructs a LSB arithmetic with robust. The original image is disparted into 8×8 blocks, and the LSB of middle and low frequency is displaced with the watermark with the 20 times intension of the replaced part's.The experiments prove that the arithmetic has strong robustness under the given situations.
Under the analysis of LSB arithmetic in frequency domain, this paper presents the situations for enhancing robustness of LSB arithmetic and two definitions for LSB in frequency domain. Based on the first definition, this paper constructs a LSB arithmetic with robust. The original image is disparted into 8×8 blocks, and the LSB of middle and low frequency is displaced with the watermark with the 20 times intension of the replaced part's.The experiments prove that the arithmetic has strong robustness under the given situations.
2006, 35(5): 774-776.
Abstract:
From the matrix theory and cellular automata theory, this paper presentes the homogeneous characteristic methodology of cellular automata. The methodology utilizes the state transition matrix equation and its characteristic polynomial to analyze the rule 90 and 150 additive cellular automata, and proves that if the characteristic polynomial of null boundary rule 90 and 150 linear cellular automata is non-dividable, then the states transition diagrams of the null boundary rule 90 and 150 additive cellular automata responding to the linear cellular automata have identical structure but have different states. Research indicates that this methodology have advantages in the application fields of pseudorandom sequence generation, communications, and test.
From the matrix theory and cellular automata theory, this paper presentes the homogeneous characteristic methodology of cellular automata. The methodology utilizes the state transition matrix equation and its characteristic polynomial to analyze the rule 90 and 150 additive cellular automata, and proves that if the characteristic polynomial of null boundary rule 90 and 150 linear cellular automata is non-dividable, then the states transition diagrams of the null boundary rule 90 and 150 additive cellular automata responding to the linear cellular automata have identical structure but have different states. Research indicates that this methodology have advantages in the application fields of pseudorandom sequence generation, communications, and test.
2006, 35(5): 777-779,783.
Abstract:
This paper presents the method and results of measurement of radiation power for Ka-band relativistic diffraction generator. The RDG device has two section slow wave structure. For the character of complete overmoded SWS, the spatial integral method of the radiation power measurement is carried out. The radiation mode image and total power are obtained by hot test, which is based on precisely calibrating of the measurement system. The measurement results show that the radiation power exceeds 300 MW with a frequency of 34~38 GHz and a pulse width exceeds 10 ns, and the radition mode is TM0n mode.
This paper presents the method and results of measurement of radiation power for Ka-band relativistic diffraction generator. The RDG device has two section slow wave structure. For the character of complete overmoded SWS, the spatial integral method of the radiation power measurement is carried out. The radiation mode image and total power are obtained by hot test, which is based on precisely calibrating of the measurement system. The measurement results show that the radiation power exceeds 300 MW with a frequency of 34~38 GHz and a pulse width exceeds 10 ns, and the radition mode is TM0n mode.
2006, 35(5): 780-783.
Abstract:
This paper gives the deduction of optically modulated scatterer to measure radiation near-field through reciprocity principle and the structure of the optically modulated scatterer system. An applied optically modulated scatterer system is designed and photodiodes are used as modulation module. Good agreements for the results between the experiment and simulation are obtained.
This paper gives the deduction of optically modulated scatterer to measure radiation near-field through reciprocity principle and the structure of the optically modulated scatterer system. An applied optically modulated scatterer system is designed and photodiodes are used as modulation module. Good agreements for the results between the experiment and simulation are obtained.
2006, 35(5): 784-787.
Abstract:
Based on the heating flow equation, the tip temperature of the cone field emitters were computed self-consistently in Nottingham effect and in Jouel heating. The temperature as a function of structure parameter and physical parameter of the cone emitter was calculated. The results show that Nottingham effect, thermal conductivity and cross section determine the tip temperature obviously, the temperature from this heating cannot possibly be a cause for failure in most tips under normal operating conditions.
Based on the heating flow equation, the tip temperature of the cone field emitters were computed self-consistently in Nottingham effect and in Jouel heating. The temperature as a function of structure parameter and physical parameter of the cone emitter was calculated. The results show that Nottingham effect, thermal conductivity and cross section determine the tip temperature obviously, the temperature from this heating cannot possibly be a cause for failure in most tips under normal operating conditions.
2006, 35(5): 788-790,847.
Abstract:
This paper describes an algorithm of numerical reconstruction for coaxial digital holography by means of a single phase-shift. In this algorithm, the intensity of the reference wave, the intensity of the object wave and their interference intensity are recorded respectively, and the object wave is calculated from these three intensity frames, but the object phase is ambiguous. Then a phase-shift frame corrects the object phase. Compared with the other single phase-shift algorithm, the phase-shift frame in this algorithm is not joins in the calculations of the object wave, but makes it without ambiguity. So, the algorithm is not sensitive to the phase-shifted error.
This paper describes an algorithm of numerical reconstruction for coaxial digital holography by means of a single phase-shift. In this algorithm, the intensity of the reference wave, the intensity of the object wave and their interference intensity are recorded respectively, and the object wave is calculated from these three intensity frames, but the object phase is ambiguous. Then a phase-shift frame corrects the object phase. Compared with the other single phase-shift algorithm, the phase-shift frame in this algorithm is not joins in the calculations of the object wave, but makes it without ambiguity. So, the algorithm is not sensitive to the phase-shifted error.
2006, 35(5): 791-793,822.
Abstract:
The data packet dropout degrades the performance and network utilization of networked control system. Based on network utilization, a feedback scheduler is used to adjust the sampling periods for tasks of NCS and network resources. The integrated control-scheduling is realized and the total control performance is optimized. The emulation result shows its effective.
The data packet dropout degrades the performance and network utilization of networked control system. Based on network utilization, a feedback scheduler is used to adjust the sampling periods for tasks of NCS and network resources. The integrated control-scheduling is realized and the total control performance is optimized. The emulation result shows its effective.
2006, 35(5): 794-797.
Abstract:
This paper proposes a simulation model of direct torque control system for whole-speed range. The design of PI speed regulator is changed to improve the properties of the flux and torque of the system due to the effect of PI parameters to the system. Also the simulation model based on MATLAB/SIMULINK is given and demonstrate that this model is true and can realize the smooth translation between the flux track of hexagon and approximate circle.
This paper proposes a simulation model of direct torque control system for whole-speed range. The design of PI speed regulator is changed to improve the properties of the flux and torque of the system due to the effect of PI parameters to the system. Also the simulation model based on MATLAB/SIMULINK is given and demonstrate that this model is true and can realize the smooth translation between the flux track of hexagon and approximate circle.
2006, 35(5): 798-800,836.
Abstract:
The control rules for encoding neural sub-networks are generated by rough sets. The neural sub-networks are evolved and combined into an integrated neural network by genetic algorithm. Such neural network can be used as a controller for control systems online. The simulation results prove the effectiveness of the control mechanism.
The control rules for encoding neural sub-networks are generated by rough sets. The neural sub-networks are evolved and combined into an integrated neural network by genetic algorithm. Such neural network can be used as a controller for control systems online. The simulation results prove the effectiveness of the control mechanism.
2006, 35(5): 801-803,810.
Abstract:
This paper introduces a method of intrude detection based on data fusion, and presents a new mechanism-DFIDM. In DFIDM, a few of sensors are configured to collect data, such as log file, information of network traffics and data package of network. After some pretreatments such as local decision-making, Data refinement, and object refinement, these data will be transferred to fusion center. In this paper, we mainly research the multiple parameters of final decision-making, such as reliability of sensors, the factor of time, the factor of space. As it showed by the research result this mechanism can improve the veracity of IDS.
This paper introduces a method of intrude detection based on data fusion, and presents a new mechanism-DFIDM. In DFIDM, a few of sensors are configured to collect data, such as log file, information of network traffics and data package of network. After some pretreatments such as local decision-making, Data refinement, and object refinement, these data will be transferred to fusion center. In this paper, we mainly research the multiple parameters of final decision-making, such as reliability of sensors, the factor of time, the factor of space. As it showed by the research result this mechanism can improve the veracity of IDS.
2006, 35(5): 804-806,840.
Abstract:
This paper designs an antibody network(ABNET) based on immune algorithm and neural network used for Intrusion Detection System. The ABNET system combines network-based intrusion detection functions. It can be used to protect large area network and has relatively good expansibility. This paper also discusses the theory of the ABNET. The algorithm has been tested on a network data set. The result shows that it had much better performance than traditional ABNET.
This paper designs an antibody network(ABNET) based on immune algorithm and neural network used for Intrusion Detection System. The ABNET system combines network-based intrusion detection functions. It can be used to protect large area network and has relatively good expansibility. This paper also discusses the theory of the ABNET. The algorithm has been tested on a network data set. The result shows that it had much better performance than traditional ABNET.
2006, 35(5): 807-810.
Abstract:
A frame component model applied to embedded software of intelligent household appliances is formulated in the paper, through the research of MCU architecture, programming language, household appliances function, and drivers of peripheral equipment. This model implements a method which rules how to design, compartmentalize and encapsulate frame codes segments. This model had been successfully used in an item in 863 Project.
A frame component model applied to embedded software of intelligent household appliances is formulated in the paper, through the research of MCU architecture, programming language, household appliances function, and drivers of peripheral equipment. This model implements a method which rules how to design, compartmentalize and encapsulate frame codes segments. This model had been successfully used in an item in 863 Project.
2006, 35(5): 811-814.
Abstract:
The Antibody Network (ABNET), which is a new Artificial Neural Networks (ANN) based on immune principle, has been proved to have good ability of unsupervised and competitive learning in experiments. But there is no precedent to use ABNET in practical engineerings because the present researches about it are still focusing on principle and experiments. While the good qualities of ABNET are reserved, such as structure generated automatically, unsupervised and competitive learning based on clone selection and mutation,the way of initiating ABNET, expressing a antibody, and updating structure is improved properly. The mail filter based on improved ABNET is better at adaptation and accuracy in experiments, compared with traditional mail filters.
The Antibody Network (ABNET), which is a new Artificial Neural Networks (ANN) based on immune principle, has been proved to have good ability of unsupervised and competitive learning in experiments. But there is no precedent to use ABNET in practical engineerings because the present researches about it are still focusing on principle and experiments. While the good qualities of ABNET are reserved, such as structure generated automatically, unsupervised and competitive learning based on clone selection and mutation,the way of initiating ABNET, expressing a antibody, and updating structure is improved properly. The mail filter based on improved ABNET is better at adaptation and accuracy in experiments, compared with traditional mail filters.
2006, 35(5): 815-818.
Abstract:
A new design method of building a multipurpose switch fabric with dynamic gigaspeed link multiplex technology is presented through analyzing switch fabric and the processing of frame forwarding in switch ASIC. The hardware designing problem how to combine multi-purpose such as firewall in the traditional switch is solved. The principle is that the firewall card and line cards share the link which link switch card through the cross-point switch. This link can be configed by CPU and changed dynamically, so it can carry out parallel communication. The results of tested pattern prove that this designing is correct.
A new design method of building a multipurpose switch fabric with dynamic gigaspeed link multiplex technology is presented through analyzing switch fabric and the processing of frame forwarding in switch ASIC. The hardware designing problem how to combine multi-purpose such as firewall in the traditional switch is solved. The principle is that the firewall card and line cards share the link which link switch card through the cross-point switch. This link can be configed by CPU and changed dynamically, so it can carry out parallel communication. The results of tested pattern prove that this designing is correct.
2006, 35(5): 819-822.
Abstract:
Based on response after the attack incidents, a method of network attack process analysis by dynamic vulnerability linking is designed. The corresponding color weighted diagraph is setup in dependence on the inference relation of the security holes in the intruded machine. With the vulnerability-log relation matrix, we searched different forensic information sources are searched. The corresponding support value and the remote suspicious host are obtaind. Then the suspicious host in the same way is analyzed. The illustration indicates that this method can get the network attack process rapidly and effectively.
Based on response after the attack incidents, a method of network attack process analysis by dynamic vulnerability linking is designed. The corresponding color weighted diagraph is setup in dependence on the inference relation of the security holes in the intruded machine. With the vulnerability-log relation matrix, we searched different forensic information sources are searched. The corresponding support value and the remote suspicious host are obtaind. Then the suspicious host in the same way is analyzed. The illustration indicates that this method can get the network attack process rapidly and effectively.
2006, 35(5): 823-825,828.
Abstract:
The ZnO thin films are prepared on glass sheets by sol-gel technology, which are characterized by X-ray diffraction, atomic force microscopy and ultra-violet spectrum. The results indicate that the thin films are c-orientation, highly visible transmittance, homogeneous and dense surface with the crystalline structure of hexagonal wurtizite, the crystalline dimension of 40～90 nm. The crystal size increases with the increasing sol concentration, and the films are highly oriented in (002) direction as the growing of the film layers. The transmittance has a sharp fundamental absorption edge in UV region, the optical band gap is evaluate to be around 3.34 eV.
The ZnO thin films are prepared on glass sheets by sol-gel technology, which are characterized by X-ray diffraction, atomic force microscopy and ultra-violet spectrum. The results indicate that the thin films are c-orientation, highly visible transmittance, homogeneous and dense surface with the crystalline structure of hexagonal wurtizite, the crystalline dimension of 40～90 nm. The crystal size increases with the increasing sol concentration, and the films are highly oriented in (002) direction as the growing of the film layers. The transmittance has a sharp fundamental absorption edge in UV region, the optical band gap is evaluate to be around 3.34 eV.
2006, 35(5): 826-828.
Abstract:
Nafion solution has been widely applied in many fields, for example, the fuel cell, the modifying electrode, the electrochemistry analysis, and the electrochemistry catalyze. The technique of preparation of special Nafion solution by using high boiling-point dissolvent is reported. Comparing the IR spectrum of the casting Nafion membrane with the original Nafion membrane, it is know that the preparation method of special Nafion solution could not change the chemical composition and the molecule structure of the Nafion membrane, and that the molecule arrangement of the casting Nafion membrane is more orderliness than the original Nafion membrane. This solution obtained in the technique has more superiority property than the Nafion solution of water-alcohols (low boiling-point) system when it is used in the PEMFC.
Nafion solution has been widely applied in many fields, for example, the fuel cell, the modifying electrode, the electrochemistry analysis, and the electrochemistry catalyze. The technique of preparation of special Nafion solution by using high boiling-point dissolvent is reported. Comparing the IR spectrum of the casting Nafion membrane with the original Nafion membrane, it is know that the preparation method of special Nafion solution could not change the chemical composition and the molecule structure of the Nafion membrane, and that the molecule arrangement of the casting Nafion membrane is more orderliness than the original Nafion membrane. This solution obtained in the technique has more superiority property than the Nafion solution of water-alcohols (low boiling-point) system when it is used in the PEMFC.
2006, 35(5): 829-832.
Abstract:
Based on optical triangulation measuring principle, an inner diameter non-contact measuring method is presented in this paper. First, the principle of optical single-triangulation which is used for non-contact measurement of inner diameter is analyzed and described. The corresponding formula for calculating the dimension of inner diameter is presented. The mathematics model for solving eccentricity of optical head which is adopted in the optical single-triangulation method is founded. The paper adopts optical single-triangulation measuring principle to design a system of inner diameter non-contact measurement with the technique of laser collimation, modern sensor, servocontrol, computer, etc. In this paper, the constitution and overall structure of the system are described, and also, the accuracy of system is verified by experiments. The measuring system resolving power can reach 0.01 mm, the limited measuring error not more than 0.03 mm. It indicates that the measuring method is applicable.
Based on optical triangulation measuring principle, an inner diameter non-contact measuring method is presented in this paper. First, the principle of optical single-triangulation which is used for non-contact measurement of inner diameter is analyzed and described. The corresponding formula for calculating the dimension of inner diameter is presented. The mathematics model for solving eccentricity of optical head which is adopted in the optical single-triangulation method is founded. The paper adopts optical single-triangulation measuring principle to design a system of inner diameter non-contact measurement with the technique of laser collimation, modern sensor, servocontrol, computer, etc. In this paper, the constitution and overall structure of the system are described, and also, the accuracy of system is verified by experiments. The measuring system resolving power can reach 0.01 mm, the limited measuring error not more than 0.03 mm. It indicates that the measuring method is applicable.
2006, 35(5): 833-836.
Abstract:
Heart rate variability is nonstationary and shows 1/f fluctuation. Based on averaged power spectrum and least square algorithm, the deduced spectral parameter is further used to analyze the heart rate variability of congestive heart failure patients and normal people. The most spectral parameters corresponding to congestive heart failure patients are smaller than 1, and the most spectral parameters corresponding to normal people are larger than 1. This fact could provide an assistant method for the diagnosis and prediagnosis of cardiopathy.
Heart rate variability is nonstationary and shows 1/f fluctuation. Based on averaged power spectrum and least square algorithm, the deduced spectral parameter is further used to analyze the heart rate variability of congestive heart failure patients and normal people. The most spectral parameters corresponding to congestive heart failure patients are smaller than 1, and the most spectral parameters corresponding to normal people are larger than 1. This fact could provide an assistant method for the diagnosis and prediagnosis of cardiopathy.
2006, 35(5): 837-840.
Abstract:
The major signal in protein coding regions of genomic sequence is three-base periodicity. We use Fourier transform as a spectral analysis tool for genes detection, all that is required is a spot Fourier coefficient at M/3, and the complete Fourier spectrum is not required. An algorithm for computing spot Fourier coefficients is presented. Thereby, a method is developed to recognize the protein coding region of genomic sequence quickly. An important feature of the method is that its computational speed is very fast. Furthermore, this method is independent of training sets or existing datebase information and thus can find general applications.
The major signal in protein coding regions of genomic sequence is three-base periodicity. We use Fourier transform as a spectral analysis tool for genes detection, all that is required is a spot Fourier coefficient at M/3, and the complete Fourier spectrum is not required. An algorithm for computing spot Fourier coefficients is presented. Thereby, a method is developed to recognize the protein coding region of genomic sequence quickly. An important feature of the method is that its computational speed is very fast. Furthermore, this method is independent of training sets or existing datebase information and thus can find general applications.
2006, 35(5): 841-843.
Abstract:
Reduced-order models of MEMS devices are the key step of system-level simulation for MEMS. It is an effective way that reduced-order models of MEMS devices are established based on linear orthogonal mode shapes. The differential equations of dynamic reduced-order models are deduced. According to the law of energy conservation, every energy domain of the system can be represented by generalizing coordinates, and the coupled differential equations can be solved by superposition of linear orthogonal mode shapes. Consequently, a set of differential equations representing dynamic characteristics of MEMS devices can be expressed. As a result, the system-level simulation can be performed by existing software of circuit simulation.
Reduced-order models of MEMS devices are the key step of system-level simulation for MEMS. It is an effective way that reduced-order models of MEMS devices are established based on linear orthogonal mode shapes. The differential equations of dynamic reduced-order models are deduced. According to the law of energy conservation, every energy domain of the system can be represented by generalizing coordinates, and the coupled differential equations can be solved by superposition of linear orthogonal mode shapes. Consequently, a set of differential equations representing dynamic characteristics of MEMS devices can be expressed. As a result, the system-level simulation can be performed by existing software of circuit simulation.
2006, 35(5): 844-847.
Abstract:
An automatic NDT system for longitudinal thermal stresses in continuously welded rails with LCR wave, which is based on acoustoelastic theory, is described in this paper. The working principles of ultrasonic probehead and the LCR wave flight-time measured unit in the system are also introduced. In order to achieve the demands of railway, the linearity and the influence of temperature to system program is cousidered.
An automatic NDT system for longitudinal thermal stresses in continuously welded rails with LCR wave, which is based on acoustoelastic theory, is described in this paper. The working principles of ultrasonic probehead and the LCR wave flight-time measured unit in the system are also introduced. In order to achieve the demands of railway, the linearity and the influence of temperature to system program is cousidered.
2006, 35(5): 848-850.
Abstract:
A partition of a positive integer n is representation of n as an unordered sum of one or more positive integers. The number of different partitions of the positive integer n is called the partition number of n. In this paper, a sufficient and necessary condition of the positive integer n which can be represented as a sum of some continuous even or odd numbers is given. The partition numbers of these two kinds of partitions are also obtained. These consequences are used for research the equation x2-y2=n. The condition of the equation existence solution and number of solution are given. For given n and m, we also show that if n can be represented as a sum of m continuous even or odd numbers, then the representation is unique.
A partition of a positive integer n is representation of n as an unordered sum of one or more positive integers. The number of different partitions of the positive integer n is called the partition number of n. In this paper, a sufficient and necessary condition of the positive integer n which can be represented as a sum of some continuous even or odd numbers is given. The partition numbers of these two kinds of partitions are also obtained. These consequences are used for research the equation x2-y2=n. The condition of the equation existence solution and number of solution are given. For given n and m, we also show that if n can be represented as a sum of m continuous even or odd numbers, then the representation is unique.
2006, 35(5): 851-853.
Abstract:
A method for construction of biorthogonal multiwavelet packets with scale=a is proposed in this paper. They are more flexible in application. The space L2(R) can be decomposed by using the proposed multiwavelet packets. The algorithms of decomposition and reconstruction of biorthogonal multiwavelet packets are given finally.
A method for construction of biorthogonal multiwavelet packets with scale=a is proposed in this paper. They are more flexible in application. The space L2(R) can be decomposed by using the proposed multiwavelet packets. The algorithms of decomposition and reconstruction of biorthogonal multiwavelet packets are given finally.
2006, 35(5): 854-856.
Abstract:
In this paper the stability problem of project planning is discussed. Firs, the access of the work through logic matrix is recognized. the formulas of project are proposed planning reliability are derived, And then the time parameters based on two points method are proposed. With them, a solution to the random network models which are based on MATLAB+SIMULINK can be obtained.
In this paper the stability problem of project planning is discussed. Firs, the access of the work through logic matrix is recognized. the formulas of project are proposed planning reliability are derived, And then the time parameters based on two points method are proposed. With them, a solution to the random network models which are based on MATLAB+SIMULINK can be obtained.
2006, 35(5): 857-860.
Abstract:
Based on information entropy theory, the criterion of selection of credit risk assessing targets is choosing targets with larger entropy weights. This paper define an efficiency index to indicate the efficiency of the set of targets as well as the discrimination of evaluation results. An illustrative example is provided to show that, after getting rid of the target with very little entropy weight, the computing process is simplified and the validity of assessing targets is improved.
Based on information entropy theory, the criterion of selection of credit risk assessing targets is choosing targets with larger entropy weights. This paper define an efficiency index to indicate the efficiency of the set of targets as well as the discrimination of evaluation results. An illustrative example is provided to show that, after getting rid of the target with very little entropy weight, the computing process is simplified and the validity of assessing targets is improved.
