ISSN 
2005 Vol. 34, No. 4
2005, 34(4): 433-436.
Abstract:
Wavelength division multiplexing/Optical code division multiplexing access (WDM/OCDMA) networks scheme has been achieved in the paper. The performance of OCDMA and WDM/OCDMA networks are investigated in detail, the formulation of bit error rate (BER) and throughput of the networks has been deduced taking into account system chip synchronization and Additive White Gaussian Noise (AWGN). The simulation result demonstrate that the capacity of WDM/OCDMA achieve better than that of the OCDMA, and construct networks more facility and agility.
Wavelength division multiplexing/Optical code division multiplexing access (WDM/OCDMA) networks scheme has been achieved in the paper. The performance of OCDMA and WDM/OCDMA networks are investigated in detail, the formulation of bit error rate (BER) and throughput of the networks has been deduced taking into account system chip synchronization and Additive White Gaussian Noise (AWGN). The simulation result demonstrate that the capacity of WDM/OCDMA achieve better than that of the OCDMA, and construct networks more facility and agility.
2005, 34(4): 437-439,451.
Abstract:
The ultra wideband (UWB) radio models have been introduced with pulse-position-modulation (PPM), on-off-keying (OOK) and pulse-amplitude-modulation (PAM). The advantages of UWB communication have been set forth such as very high transformation rates, excellent security, fading against multi-path, and so on. The closed form expression of the time domain and power spectrum density has been derived, and the power spectrum has been analyzed for the signal of UWB communication, and the power spectrum of the real signal of UWB communication has been simulated by computer.
The ultra wideband (UWB) radio models have been introduced with pulse-position-modulation (PPM), on-off-keying (OOK) and pulse-amplitude-modulation (PAM). The advantages of UWB communication have been set forth such as very high transformation rates, excellent security, fading against multi-path, and so on. The closed form expression of the time domain and power spectrum density has been derived, and the power spectrum has been analyzed for the signal of UWB communication, and the power spectrum of the real signal of UWB communication has been simulated by computer.
2005, 34(4): 440-443.
Abstract:
This paper focuses on construction of efficient rate-compatible irregular repeat accumulate (RC-IRA) codes over a wide rate range. Puncturing approach is the conventional approach. But the asymptotic performance shows that it only works well when the amount of puncturing is small. To extend the dynamic rate range, a special extending approach is proposed. Repeat-accumulate codes are used to produce padded parity bits. Combined the two approaches, RC-IRA codes are constructed. Simulation results show that the throughput of RC-IRA codes applied to ARQ system have performance close to that of turbo ARQ system, yet with lower decoding complexity.
This paper focuses on construction of efficient rate-compatible irregular repeat accumulate (RC-IRA) codes over a wide rate range. Puncturing approach is the conventional approach. But the asymptotic performance shows that it only works well when the amount of puncturing is small. To extend the dynamic rate range, a special extending approach is proposed. Repeat-accumulate codes are used to produce padded parity bits. Combined the two approaches, RC-IRA codes are constructed. Simulation results show that the throughput of RC-IRA codes applied to ARQ system have performance close to that of turbo ARQ system, yet with lower decoding complexity.
2005, 34(4): 444-447.
Abstract:
In this paper, we use a common deducing method to acquire an efficient architecture based DFT polyphase filter banks to realize wideband digital channelized receiver. Furthermore, by applying instantaneous frequency measurement (IFM) technology to that architecture, an approach of digital channelized IFM receiver is proposed. The simulation in MATLAB software indicates that approach has increased frequency resolution of channelized receiver to distinguish simultaneous two signals in one channel. And it is an efficient approach of receiver for reconnaissance which can adapt to the insensitive signals environment of modern EW for its low computing complexity and high hardware realizing efficiency.
In this paper, we use a common deducing method to acquire an efficient architecture based DFT polyphase filter banks to realize wideband digital channelized receiver. Furthermore, by applying instantaneous frequency measurement (IFM) technology to that architecture, an approach of digital channelized IFM receiver is proposed. The simulation in MATLAB software indicates that approach has increased frequency resolution of channelized receiver to distinguish simultaneous two signals in one channel. And it is an efficient approach of receiver for reconnaissance which can adapt to the insensitive signals environment of modern EW for its low computing complexity and high hardware realizing efficiency.
2005, 34(4): 448-451.
Abstract:
The total power received in Base Station(BS) reflects the situation of traffic load in uplink in central cell and adjacent cells. Based on this principle, a dynamic distribution scheme of traffic load in WCDMA system is proposed in this paper. The central Base Station(BS) periodically adjusts the power of pilot signal according to the total power received in uplink. Mobile Station(MS) is able to hand off between central cell and surrounding cells smoothly, so the dynamic distribution of traffic load is realized. The results of simulation indicates that this scheme can get good performance, the block probability and the dropping probability in uplink and downlink can be improved.
The total power received in Base Station(BS) reflects the situation of traffic load in uplink in central cell and adjacent cells. Based on this principle, a dynamic distribution scheme of traffic load in WCDMA system is proposed in this paper. The central Base Station(BS) periodically adjusts the power of pilot signal according to the total power received in uplink. Mobile Station(MS) is able to hand off between central cell and surrounding cells smoothly, so the dynamic distribution of traffic load is realized. The results of simulation indicates that this scheme can get good performance, the block probability and the dropping probability in uplink and downlink can be improved.
2005, 34(4): 452-455.
Abstract:
Noise reduction is one of the key questions needed to be solved in chaos synchronization communication. The feedback synchronization of chaotic systems commonly is non-time-lag feedback synchronization. In this paper, we present a method of time lag feedback synchronization of chaotic systems. Taking Lorenz chaotic system as a example, we have proved the sufficient condition of synchronization stability by time lag feedback control method between driver system and response system, when driver system and response system are all Lorenz system. Then, taking the method of time lag feedback synchronization to eliminate noise effect, indicate that it is much better than common synchronization method. By simulating Lorenz system parameter modulation signal transmission through the channel existing noise, we can see the noise reduction advantage of time lag feedback chaos synchronization.
Noise reduction is one of the key questions needed to be solved in chaos synchronization communication. The feedback synchronization of chaotic systems commonly is non-time-lag feedback synchronization. In this paper, we present a method of time lag feedback synchronization of chaotic systems. Taking Lorenz chaotic system as a example, we have proved the sufficient condition of synchronization stability by time lag feedback control method between driver system and response system, when driver system and response system are all Lorenz system. Then, taking the method of time lag feedback synchronization to eliminate noise effect, indicate that it is much better than common synchronization method. By simulating Lorenz system parameter modulation signal transmission through the channel existing noise, we can see the noise reduction advantage of time lag feedback chaos synchronization.
2005, 34(4): 456-459.
Abstract:
A handoff scheme is introduced in this paper, which considers the dynamic thresholds and preemptive priority level in intergrated voice and data LEO(Low Earth Orbit) satellite systems. Taking into account the characteristic of data calls and the higher priority of handoff voice calls, this scheme gives handoff voice calls a preemptive priority with combination of queuing strategy. A Guard Channel scheme based on dynamic thresholds is used in the scheme. It guarantees the priority and fairness between new calls and handoff calls. By simulation, it can be seen through comparison with the non-priority and guard channel handoff scheme that the proposed handoff scheme improves the performance of system in grade of service and channel utilization.
A handoff scheme is introduced in this paper, which considers the dynamic thresholds and preemptive priority level in intergrated voice and data LEO(Low Earth Orbit) satellite systems. Taking into account the characteristic of data calls and the higher priority of handoff voice calls, this scheme gives handoff voice calls a preemptive priority with combination of queuing strategy. A Guard Channel scheme based on dynamic thresholds is used in the scheme. It guarantees the priority and fairness between new calls and handoff calls. By simulation, it can be seen through comparison with the non-priority and guard channel handoff scheme that the proposed handoff scheme improves the performance of system in grade of service and channel utilization.
2005, 34(4): 460-463.
Abstract:
Lattice vector quantization(LVQ)outperforms LBG based vector quantizers by offering a substantial reduction in computational and storage complexity. A novel algorithm based on quadtree structure is proposed in this paper as a combination of wavelet transform and LVQ. First, perceptual weighting on the wavelet transform coefficients is introduced with the result of substituting normal distortion measure Mean Square Error(MSE)with perceptually based one. To exploiting both frequency and spatial compaction of energy of wavelet, a framework with improved zerotree coding followed by LVQ is developed. Codeword is organized based on directional quadtree structure to take advantages of the inherent properties of the wavelet transform coefficients. Stimulation shows, compared with other algorithms in literature, this algorithm has distinct advantages of high coding efficiency with fast speed and small storage requirement.
Lattice vector quantization(LVQ)outperforms LBG based vector quantizers by offering a substantial reduction in computational and storage complexity. A novel algorithm based on quadtree structure is proposed in this paper as a combination of wavelet transform and LVQ. First, perceptual weighting on the wavelet transform coefficients is introduced with the result of substituting normal distortion measure Mean Square Error(MSE)with perceptually based one. To exploiting both frequency and spatial compaction of energy of wavelet, a framework with improved zerotree coding followed by LVQ is developed. Codeword is organized based on directional quadtree structure to take advantages of the inherent properties of the wavelet transform coefficients. Stimulation shows, compared with other algorithms in literature, this algorithm has distinct advantages of high coding efficiency with fast speed and small storage requirement.
2005, 34(4): 464-466.
Abstract:
This paper gives the particular description of a theoretical analysis and practical design for high IF frequency millimeter-wave subharmonic mixer with three one-dimensional photonic bandgap (PBG) cells. Base on computer aided design, a Ka-band 4th harmonic mixer has been designed and tested. When IF frequency is 3 GHz, and RF frequency varied from 34~35.8 GHz, the conversion loss is less than 14.5 dB and the least is 11 dB. The results of simulation and test show that the formulas are correct and the scheme is practicable.
This paper gives the particular description of a theoretical analysis and practical design for high IF frequency millimeter-wave subharmonic mixer with three one-dimensional photonic bandgap (PBG) cells. Base on computer aided design, a Ka-band 4th harmonic mixer has been designed and tested. When IF frequency is 3 GHz, and RF frequency varied from 34~35.8 GHz, the conversion loss is less than 14.5 dB and the least is 11 dB. The results of simulation and test show that the formulas are correct and the scheme is practicable.
2005, 34(4): 467-469,473.
Abstract:
A fast RLS algorithm for second-order Volterra filter is analyzed. And the contradiction between speed and accuracy of convergence is revealed. The modified RLS algorithm is presented by substituting constant forgetting-factor with function of forgetting-factor constructed in this paper. The rules for constructing forgetting-factor function and the method for selecting parameters is discussed. Finally, a numerical example shows that the modified RLS algorithm result in faster convergence speed by solving the contradiction between speed and accuracy.
A fast RLS algorithm for second-order Volterra filter is analyzed. And the contradiction between speed and accuracy of convergence is revealed. The modified RLS algorithm is presented by substituting constant forgetting-factor with function of forgetting-factor constructed in this paper. The rules for constructing forgetting-factor function and the method for selecting parameters is discussed. Finally, a numerical example shows that the modified RLS algorithm result in faster convergence speed by solving the contradiction between speed and accuracy.
2005, 34(4): 470-473.
Abstract:
The thermal analysis is more important for high reliability and short design cycles in electronic gun design. The high temperature, produced during electronic gun working, results to the thermal-stress of the components, and has effects to the parameters and lifetime of the gun. This paper provided the thermal and structural analysis of the electronic gun using ANSYS package. The results of thermal and structural analysis for complex and simple model were compared. The results of thermal analysis are helpful to the optimizing design of electronic gun.
The thermal analysis is more important for high reliability and short design cycles in electronic gun design. The high temperature, produced during electronic gun working, results to the thermal-stress of the components, and has effects to the parameters and lifetime of the gun. This paper provided the thermal and structural analysis of the electronic gun using ANSYS package. The results of thermal and structural analysis for complex and simple model were compared. The results of thermal analysis are helpful to the optimizing design of electronic gun.
2005, 34(4): 474-477.
Abstract:
Ion noise of TWTs and klystrons are analyzed using small signal method by motion theory and moment theory. The relationship between phase noise and signal frequency, voltage fluctuation are obtained. From the analysis results we find when the amplitude of voltage fluctuation and signal frequency increase, the phase noise would increase.
Ion noise of TWTs and klystrons are analyzed using small signal method by motion theory and moment theory. The relationship between phase noise and signal frequency, voltage fluctuation are obtained. From the analysis results we find when the amplitude of voltage fluctuation and signal frequency increase, the phase noise would increase.
2005, 34(4): 478-480.
Abstract:
For the necessity of thermal analysis for traveling-wave tube's slow-wave structure, the mechanism of thermal generation in coupled-cavity slow-wave structure has been shown. A professional simulation software combining with the software ANSYS which can do thermal analysis for different type of coupled-cavity slow-wave structure has been designed. Using this software, tube designer can do simulation about thermal performance of coupled-cavity traveling-wave tube's slow-wave structure without the knowledge of how to use ANSYS.
For the necessity of thermal analysis for traveling-wave tube's slow-wave structure, the mechanism of thermal generation in coupled-cavity slow-wave structure has been shown. A professional simulation software combining with the software ANSYS which can do thermal analysis for different type of coupled-cavity slow-wave structure has been designed. Using this software, tube designer can do simulation about thermal performance of coupled-cavity traveling-wave tube's slow-wave structure without the knowledge of how to use ANSYS.
2005, 34(4): 481-484.
Abstract:
The physical mechanism of explosive emission was analyzed. The conditions of emission and the formula to calculate the charge that would be drawn away from the cathode surface were educed based on the Yee model. Especially, discuss how to use the way of phenomenological description to realize particle-in-cell simulation in two-dimensional of explosive emission. Inward-emitting coaxial diode was used as an example to validate the corrections of simulation from current-voltage correlation and characteristic of electron beam movement.
The physical mechanism of explosive emission was analyzed. The conditions of emission and the formula to calculate the charge that would be drawn away from the cathode surface were educed based on the Yee model. Especially, discuss how to use the way of phenomenological description to realize particle-in-cell simulation in two-dimensional of explosive emission. Inward-emitting coaxial diode was used as an example to validate the corrections of simulation from current-voltage correlation and characteristic of electron beam movement.
2005, 34(4): 485-488.
Abstract:
CHIPIC is a particle-in-cell(PIC)software which is used to solve the high power microwave electromagnetic field problems, the electromagnetic field algorithm is a key module to it. This paper gives its basic electromagnetic field algorithms-center difference algorithm and time-biased difference algorithm. The simulation results of CHIPIC code are in accord with the MAGIC code.
CHIPIC is a particle-in-cell(PIC)software which is used to solve the high power microwave electromagnetic field problems, the electromagnetic field algorithm is a key module to it. This paper gives its basic electromagnetic field algorithms-center difference algorithm and time-biased difference algorithm. The simulation results of CHIPIC code are in accord with the MAGIC code.
2005, 34(4): 489-492.
Abstract:
With the combination of wireless network and Internet, mobile subscribers will certainly access Internet, so it is very necessary to simulate protocols in WAP. Based on the simulation to WTLS protocol in WAP, this paper evaluates WTLS protocol. We adopt the software OPNET to build network topology, node model, etc, and acquire the protocol's simulation performance results in moving subscriber numbers, moving subscribers' average session time, channel rates variety, etc. The important indexes include packet delay, response delay change quantities and response time. These performances will seriously affect real time response signal.
With the combination of wireless network and Internet, mobile subscribers will certainly access Internet, so it is very necessary to simulate protocols in WAP. Based on the simulation to WTLS protocol in WAP, this paper evaluates WTLS protocol. We adopt the software OPNET to build network topology, node model, etc, and acquire the protocol's simulation performance results in moving subscriber numbers, moving subscribers' average session time, channel rates variety, etc. The important indexes include packet delay, response delay change quantities and response time. These performances will seriously affect real time response signal.
2005, 34(4): 493-496.
Abstract:
This paper addresses a local eigenspectra-based scheme for face recognition, wherein each face is partitioned into a suitable number of blocks, followed by energy normalizing to reduce the brightness variation effect and by the Fourier transform to estimate the spectra of each block. Features called eigenspectra are obtained by the principal component analysis(PCA) on the same serial number blocks, and then classified by the nearest neighbor(NN) rule. Experiments taken on the Olivetti Research Laboratory(ORL) face database show the feasibility of the addressed method for face recognition.
This paper addresses a local eigenspectra-based scheme for face recognition, wherein each face is partitioned into a suitable number of blocks, followed by energy normalizing to reduce the brightness variation effect and by the Fourier transform to estimate the spectra of each block. Features called eigenspectra are obtained by the principal component analysis(PCA) on the same serial number blocks, and then classified by the nearest neighbor(NN) rule. Experiments taken on the Olivetti Research Laboratory(ORL) face database show the feasibility of the addressed method for face recognition.
2005, 34(4): 497-500.
Abstract:
In this paper, we proposed a facial feature locating algorithm based on inter-frame-differential and skin color-space segmentation. First, we utilize the moving information to calculate the binary inter-frame differential image and extract edge and locate a gross position of the target. Secondly, we design the skin color model and use the color space transform to accurately locate human-face. using inter-frame-differential algorithm can remove possible disturbing background in complicate environment which is quite possible in application, Using skin-color can further restrict the interest region to face. Doing feature extraction after the two-step preprocessing could not only remove environmental noise and decrease false identification, but also, as it largely down-size the searching-area, it actually increased the total processing speed. The results of the applications show that based on inter-frame-differential and skin color-space algorithm is practical and efficient.
In this paper, we proposed a facial feature locating algorithm based on inter-frame-differential and skin color-space segmentation. First, we utilize the moving information to calculate the binary inter-frame differential image and extract edge and locate a gross position of the target. Secondly, we design the skin color model and use the color space transform to accurately locate human-face. using inter-frame-differential algorithm can remove possible disturbing background in complicate environment which is quite possible in application, Using skin-color can further restrict the interest region to face. Doing feature extraction after the two-step preprocessing could not only remove environmental noise and decrease false identification, but also, as it largely down-size the searching-area, it actually increased the total processing speed. The results of the applications show that based on inter-frame-differential and skin color-space algorithm is practical and efficient.
2005, 34(4): 501-504.
Abstract:
This paper analyses the deficiency of packet handling in active networks, and presents A Flow-dispatching model named A-Flow on active networks. In this paper a project of ANTS over A-Flow is implemented. The new model is based on ANEP, it can make multiple execution environments interoperate on the same node, and it has functions of packet buffering, identification and payload dispatching, which may improve the performance and security of active nodes.
This paper analyses the deficiency of packet handling in active networks, and presents A Flow-dispatching model named A-Flow on active networks. In this paper a project of ANTS over A-Flow is implemented. The new model is based on ANEP, it can make multiple execution environments interoperate on the same node, and it has functions of packet buffering, identification and payload dispatching, which may improve the performance and security of active nodes.
2005, 34(4): 505-508.
Abstract:
This paper presents a model of spam mail filter based on artificial neural network which is optimized by genetic algorithms. By using genetic algorithms, which is good at wide searching ability in solution space on optimizing connection weight matrix of artificial neural network, artificial neural network can get over the inherent limitation of local minimal and improve its learning speed and recognition ability. The application of the model in spam filter has been successfully proved by its implementing.
This paper presents a model of spam mail filter based on artificial neural network which is optimized by genetic algorithms. By using genetic algorithms, which is good at wide searching ability in solution space on optimizing connection weight matrix of artificial neural network, artificial neural network can get over the inherent limitation of local minimal and improve its learning speed and recognition ability. The application of the model in spam filter has been successfully proved by its implementing.
2005, 34(4): 509-512.
Abstract:
The principle of attack defense realized in a firewall embedded in Linux kernel has been discussed. Based on the analysis of characteristic of network attack, the mechanism and architecture of attack defense are built in accordance. Through the introduce of stateful detection, the attack defense framework is built to determine and prevent the deportment of various attack. Thereafter, the architecture of attack-removed system can be expected to be general-purpose and easy to be extended. The performance of the whole firewall system is enhanced because the attack defense system effectively overcomes the limitation of conventional packet-filtering firewall. The experiments for validating the improvement of IP security are given as well as the research work.
The principle of attack defense realized in a firewall embedded in Linux kernel has been discussed. Based on the analysis of characteristic of network attack, the mechanism and architecture of attack defense are built in accordance. Through the introduce of stateful detection, the attack defense framework is built to determine and prevent the deportment of various attack. Thereafter, the architecture of attack-removed system can be expected to be general-purpose and easy to be extended. The performance of the whole firewall system is enhanced because the attack defense system effectively overcomes the limitation of conventional packet-filtering firewall. The experiments for validating the improvement of IP security are given as well as the research work.
2005, 34(4): 513-516.
Abstract:
Allusion to the limitation of the traditional boundary firewall in dynamic defense, the thesis analyses and compares three interactive technologies between firewall and intrusion-detection system and proposes a boundary defense system model which with the function of firewall and intrusion detection adopts system embedded mode based on the distributed firewall environment. It implements firewall cooperates with intrusion detection by queue communication. Firewall and intrusion detect and defend intrusion to system and connect to distributed firewall by secure communicating module. Finally the thesis expatiates on the realization in Linux.
Allusion to the limitation of the traditional boundary firewall in dynamic defense, the thesis analyses and compares three interactive technologies between firewall and intrusion-detection system and proposes a boundary defense system model which with the function of firewall and intrusion detection adopts system embedded mode based on the distributed firewall environment. It implements firewall cooperates with intrusion detection by queue communication. Firewall and intrusion detect and defend intrusion to system and connect to distributed firewall by secure communicating module. Finally the thesis expatiates on the realization in Linux.
2005, 34(4): 517-520.
Abstract:
The applying of the large scale and super large scale integrate circuit in electronic systems gradually abroad. The research to the fault diagnosis design for testability of the digital system draws the technologist's fully attention. Multi-fault formula were given in this paper. The paper stresses the fault diagnosis and test set and design for testability by Boolean algebra method.
The applying of the large scale and super large scale integrate circuit in electronic systems gradually abroad. The research to the fault diagnosis design for testability of the digital system draws the technologist's fully attention. Multi-fault formula were given in this paper. The paper stresses the fault diagnosis and test set and design for testability by Boolean algebra method.
2005, 34(4): 521-524.
Abstract:
This paper presents a distributed file system based on E-mail named E-mail distributed file system. This paper gives the state and definition of extension STMP, based on this we design the model and method of the EMDFS, and propose the store space, the memory and disk structure of EMDFS, the I/O operators, user interface, and other functions.
This paper presents a distributed file system based on E-mail named E-mail distributed file system. This paper gives the state and definition of extension STMP, based on this we design the model and method of the EMDFS, and propose the store space, the memory and disk structure of EMDFS, the I/O operators, user interface, and other functions.
2005, 34(4): 525-528.
Abstract:
This article has a research on a embedded C Runtime Library:newlib. It presents the way to accomplish the reentry of newlib under multi-task environment. It introduces stub functions implementation which is needed by porting newlib on embedded system, especially open, close, read and write implementation which relate with I/O, and malloc two implementation ways.
This article has a research on a embedded C Runtime Library:newlib. It presents the way to accomplish the reentry of newlib under multi-task environment. It introduces stub functions implementation which is needed by porting newlib on embedded system, especially open, close, read and write implementation which relate with I/O, and malloc two implementation ways.
2005, 34(4): 529-532.
Abstract:
With server cluster technology, a high available cluster system based on Linux is designed. This thesis expounds the system's model、designing idea and implement. In system designing, each part of the system is designed separately to reduce system's design complexity and to make it easier to inspect system's error. Diversity and complexity of application servers are fully considered. Test proves that the system can ensure servers' reliable run and security of enterprise users' kernel computing effectively.
With server cluster technology, a high available cluster system based on Linux is designed. This thesis expounds the system's model、designing idea and implement. In system designing, each part of the system is designed separately to reduce system's design complexity and to make it easier to inspect system's error. Diversity and complexity of application servers are fully considered. Test proves that the system can ensure servers' reliable run and security of enterprise users' kernel computing effectively.
2005, 34(4): 533-536.
Abstract:
In this paper, RST is integrated with SVM, and knowledge reduction system is constructed based on RST and SVM, and integrated Rough Set Theory into SVM. Then Intrusion Detection System (IDS) based on RST and SVM is built by analyzing IDS. Finally, comparison of detection ability between the above detection method and others is given. So the IDS based on RST and SVM is a better project.
In this paper, RST is integrated with SVM, and knowledge reduction system is constructed based on RST and SVM, and integrated Rough Set Theory into SVM. Then Intrusion Detection System (IDS) based on RST and SVM is built by analyzing IDS. Finally, comparison of detection ability between the above detection method and others is given. So the IDS based on RST and SVM is a better project.
2005, 34(4): 537-540.
Abstract:
The paper presents an algorithm based on PDF417 two dimensional bar codes' structure. It first proposes a filter to eliminate noise, then deals with vertical scratches and those points that do not comply with the bar codes' boundary characteristics by a point-search strategy. Later, during process of restoring the bar coded pictures, the contaminations will not be restored because-their seeds for restoration have been cleaned beforehand. This algorithm features a reliable picture restoration that is free from the negative consequences imposed on the effective bar code edges by filtering. The restored pictures can be decoded by the improved edge-detecting projection method. Experiments have proved that this algorithm improves efficiency and accuracy of the decoding process while demanding a lower error correcting level.
The paper presents an algorithm based on PDF417 two dimensional bar codes' structure. It first proposes a filter to eliminate noise, then deals with vertical scratches and those points that do not comply with the bar codes' boundary characteristics by a point-search strategy. Later, during process of restoring the bar coded pictures, the contaminations will not be restored because-their seeds for restoration have been cleaned beforehand. This algorithm features a reliable picture restoration that is free from the negative consequences imposed on the effective bar code edges by filtering. The restored pictures can be decoded by the improved edge-detecting projection method. Experiments have proved that this algorithm improves efficiency and accuracy of the decoding process while demanding a lower error correcting level.
2005, 34(4): 541-544.
Abstract:
According to the holography reconstruction formula educed from Kirchhoff integral formula, this paper introduces the principle of near-field acoustical holography(NAH)in noise identification and reconstructs the acoustic field by a special arithmetic of dimensional frequency domain in order to reduce the quantity of calculation and improve the efficiency of reconstruction. Meanwhile, the affection of the main parameters of calculating and testing system on the results of noise identification is analyzed and the correctness of the reconstructing formula is validated. As a result, a computer testing and calculating program has been developed. The experimental outcomes indicate that with the revision of the reconstructing formula and taking the influences of the measuring system's parameters into account sufficiently according to the practical conditions, the acoustic holography can be used to distinguish the sources of noises from each other efficiently so to provide the dependable basis for taking the noise control measures.
According to the holography reconstruction formula educed from Kirchhoff integral formula, this paper introduces the principle of near-field acoustical holography(NAH)in noise identification and reconstructs the acoustic field by a special arithmetic of dimensional frequency domain in order to reduce the quantity of calculation and improve the efficiency of reconstruction. Meanwhile, the affection of the main parameters of calculating and testing system on the results of noise identification is analyzed and the correctness of the reconstructing formula is validated. As a result, a computer testing and calculating program has been developed. The experimental outcomes indicate that with the revision of the reconstructing formula and taking the influences of the measuring system's parameters into account sufficiently according to the practical conditions, the acoustic holography can be used to distinguish the sources of noises from each other efficiently so to provide the dependable basis for taking the noise control measures.
2005, 34(4): 545-547.
Abstract:
Improving models' precision and ensuring equation's resolution constringency are two unresolved problems in engine modeling. The mathematical model of twin-rotor accelerating turbo-jet engine is taken as an example to illustrate the modeling of linear state-space model. A method is proposed for dividing the flight envelope into a number of sub-regions in witch the perturbations of aeroengine model are relatively small.
Improving models' precision and ensuring equation's resolution constringency are two unresolved problems in engine modeling. The mathematical model of twin-rotor accelerating turbo-jet engine is taken as an example to illustrate the modeling of linear state-space model. A method is proposed for dividing the flight envelope into a number of sub-regions in witch the perturbations of aeroengine model are relatively small.
2005, 34(4): 548-551.
Abstract:
Structure of design optimization and simulation system used for raw materials mixing system of steelworks was proposed based on parametric modeling and virtual reality techniques. Design optimization, workshop parametric modeling and material transport simulation were researched; the integrated design automation and simulation system was developed. Application showed that the system leverage the design automation of raw materials mixing workshop.
Structure of design optimization and simulation system used for raw materials mixing system of steelworks was proposed based on parametric modeling and virtual reality techniques. Design optimization, workshop parametric modeling and material transport simulation were researched; the integrated design automation and simulation system was developed. Application showed that the system leverage the design automation of raw materials mixing workshop.
2005, 34(4): 552-555.
Abstract:
This paper focuses on the mathematical model of weapon Fire-control-system simulator. A new scheme for designing the weapon fire-control-system simulator with single chip microcomputer is proposed. The single chip microcomputer controller takes charge of processing position & velocity data, limitation data and keystroke identification. The single chip microcomputer monitor is to detect failure protection signals and transfer them to IPC. The idea of modularization design is adopted in the single chip microcomputer software. The experimental results show that this weapon fire-control-system simulator achieves a high control precision with easy operations and perfect functions. This simulator has completed many key simulation tasks for many kinds of Weapon Fire-control-system..
This paper focuses on the mathematical model of weapon Fire-control-system simulator. A new scheme for designing the weapon fire-control-system simulator with single chip microcomputer is proposed. The single chip microcomputer controller takes charge of processing position & velocity data, limitation data and keystroke identification. The single chip microcomputer monitor is to detect failure protection signals and transfer them to IPC. The idea of modularization design is adopted in the single chip microcomputer software. The experimental results show that this weapon fire-control-system simulator achieves a high control precision with easy operations and perfect functions. This simulator has completed many key simulation tasks for many kinds of Weapon Fire-control-system..
2005, 34(4): 556-558.
Abstract:
In this paper, the outlier mining method for time series data is investigated. DWT is used to transform the time series data from time domain to frequency domain. The time series data can be mapped into the multidimensional points in multidimensional space. We proposed a distanced-based algorithm to mine the outliers. The simulation results show the effectiveness of the method.
In this paper, the outlier mining method for time series data is investigated. DWT is used to transform the time series data from time domain to frequency domain. The time series data can be mapped into the multidimensional points in multidimensional space. We proposed a distanced-based algorithm to mine the outliers. The simulation results show the effectiveness of the method.
2005, 34(4): 559-561.
Abstract:
In allusion to the form solution to high order evolution equation, 4n-2 order evolution equation that is one of the best important standard type about time-delay distributed parameter system expand from two order evolution equation and construct the inner product to become 4n-2 dimension Halberd space at the same time. The generating operator of 4n-2 order evolution equation is obtained and it generates a semigroup when 4n-2 order evolution equation is changed into one order evolution equation set. The configuration form's semigroup is constructed and it's basic character is proved. In particular, the semigroup(n=1) intitules Golstein's.
In allusion to the form solution to high order evolution equation, 4n-2 order evolution equation that is one of the best important standard type about time-delay distributed parameter system expand from two order evolution equation and construct the inner product to become 4n-2 dimension Halberd space at the same time. The generating operator of 4n-2 order evolution equation is obtained and it generates a semigroup when 4n-2 order evolution equation is changed into one order evolution equation set. The configuration form's semigroup is constructed and it's basic character is proved. In particular, the semigroup(n=1) intitules Golstein's.
2005, 34(4): 562-565.
Abstract:
Rough set theory researched problems of tentative.uncontinuity and uncomplete in the messages space of knowledge.And it belives that the knowledge appears in people's ability of classification.This paper mainly discussed the usape in rough set theory in semigroups.Based on the qpproxion ations comcept,it brought in the rough subest,rough Descarte's product, left(right, double-sides)rough ideal and bi-rough-ideal in the semigroups.It also analyzed some of its algebra structure qualitatively. Thus it enriched rough set theory in semigroups.
Rough set theory researched problems of tentative.uncontinuity and uncomplete in the messages space of knowledge.And it belives that the knowledge appears in people's ability of classification.This paper mainly discussed the usape in rough set theory in semigroups.Based on the qpproxion ations comcept,it brought in the rough subest,rough Descarte's product, left(right, double-sides)rough ideal and bi-rough-ideal in the semigroups.It also analyzed some of its algebra structure qualitatively. Thus it enriched rough set theory in semigroups.
2005, 34(4): 566-568.
Abstract:
This paper utilizes the column action method with the greedy method and the dividing-Conquering strategy to put forward a message passing multiple instruction stream-multiple data stream (MIMD) parallel iterative method for determining the solution of arbitrary consistent band system of linear equations or the least squares solution of arbitrary inconsistent band system of linear equations, also analyzes its convergence and its computational complexity, so its numerical stability. Moreover, the method in this paper con make roughly balance of the computation workload to each processor, hence can obtained ideal speed-up and parallel efficiency.
This paper utilizes the column action method with the greedy method and the dividing-Conquering strategy to put forward a message passing multiple instruction stream-multiple data stream (MIMD) parallel iterative method for determining the solution of arbitrary consistent band system of linear equations or the least squares solution of arbitrary inconsistent band system of linear equations, also analyzes its convergence and its computational complexity, so its numerical stability. Moreover, the method in this paper con make roughly balance of the computation workload to each processor, hence can obtained ideal speed-up and parallel efficiency.
2005, 34(4): 569-572.
Abstract:
The price idex is very inportant in the economic system,and it is difficult to predict accurately it is difficult to predict accurately because of the reason and the long intervals. We solve this problems with harmonic algorithm and two-leve algorithm of GMDH.The result that we researched the problems of prediction with the theory and methods in example show thatthis method is very efficient in example.
The price idex is very inportant in the economic system,and it is difficult to predict accurately it is difficult to predict accurately because of the reason and the long intervals. We solve this problems with harmonic algorithm and two-leve algorithm of GMDH.The result that we researched the problems of prediction with the theory and methods in example show thatthis method is very efficient in example.
2005, 34(4): 573-576.
Abstract:
Because of its fatal imperfections in the logical procedure, the widely-accepted analysis in the form of phasor method applied to obtain the en-oscillating condition and the stabilizing condition for feedback oscillator prove wrong. In the paper, a general en-oscillating criterion is brought forward for the first time, and by means of this criterion, two concrete en-oscillating condition in the form of phasor method are logically deduced, which are reasonably practicable. In the end, the stabilizing condition for oscillator is sentenced to be nothing.
Because of its fatal imperfections in the logical procedure, the widely-accepted analysis in the form of phasor method applied to obtain the en-oscillating condition and the stabilizing condition for feedback oscillator prove wrong. In the paper, a general en-oscillating criterion is brought forward for the first time, and by means of this criterion, two concrete en-oscillating condition in the form of phasor method are logically deduced, which are reasonably practicable. In the end, the stabilizing condition for oscillator is sentenced to be nothing.
