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2006 Vol. 28, No. 9
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2006, 28(9): 1537-1541.
Abstract:
The dual-tree complex wavelet transform is employed in image fusion, to round the deficiencies of existing wavelet based algorithms in characteristics representation. The study of Robins et al.. shows that the local energy is robust in the representing and locating of all kinds of image features. Based on dual-tree complex wavelet transform, the local orientation energy and local energy are defined, which in conjunction with the response characteristic of human visual system to image features, the local banded contrast is finally formulated. In the real time image fusion system, inputs may be corrupted with random noises. The local orientation energy entropy is formulated, according to the different orientation energy distribution of features and noises, to modulate the local banded contrast adaptively. As a result, the robustness to noise is improved. The performance evaluations of the proposed algorithm both subjectively and objectively manifest the excellent efficacy of the new scheme.
The dual-tree complex wavelet transform is employed in image fusion, to round the deficiencies of existing wavelet based algorithms in characteristics representation. The study of Robins et al.. shows that the local energy is robust in the representing and locating of all kinds of image features. Based on dual-tree complex wavelet transform, the local orientation energy and local energy are defined, which in conjunction with the response characteristic of human visual system to image features, the local banded contrast is finally formulated. In the real time image fusion system, inputs may be corrupted with random noises. The local orientation energy entropy is formulated, according to the different orientation energy distribution of features and noises, to modulate the local banded contrast adaptively. As a result, the robustness to noise is improved. The performance evaluations of the proposed algorithm both subjectively and objectively manifest the excellent efficacy of the new scheme.
2006, 28(9): 1542-1545.
Abstract:
By modern time series analysis method, based on ARMA innovation model, under the linear minimum variance optimal information fusion criterion, the distributed fusion steady-state optimal Kalman predictors weighted by matrices, scalars, and diagonal matrices are presented for multisensor systems with correlated input and observation noises, and with correlated observation noises, respectively. Based on the Lyapunov equations, the formulas of computing local predicting error variances and covariances are given, which are applied to compute optimal weights. Compared to the single sensor case, the accuracy of the fused predictor is improved. A simulation example for tracking systems shows its effectiveness, and shows that the accuracy distinction of the predictors weighted by three ways is not obvious, but the predictor weighted by scalars can obviously reduce the computational burden, and provides a fast real time information fusion estimation algorithm.
By modern time series analysis method, based on ARMA innovation model, under the linear minimum variance optimal information fusion criterion, the distributed fusion steady-state optimal Kalman predictors weighted by matrices, scalars, and diagonal matrices are presented for multisensor systems with correlated input and observation noises, and with correlated observation noises, respectively. Based on the Lyapunov equations, the formulas of computing local predicting error variances and covariances are given, which are applied to compute optimal weights. Compared to the single sensor case, the accuracy of the fused predictor is improved. A simulation example for tracking systems shows its effectiveness, and shows that the accuracy distinction of the predictors weighted by three ways is not obvious, but the predictor weighted by scalars can obviously reduce the computational burden, and provides a fast real time information fusion estimation algorithm.
2006, 28(9): 1546-1549.
Abstract:
Due to the reasons of sensors in itself and the communication delays, the research of the asynchronous multisensor data fusion problem is more practical than that of synchronous one. Based on minimizing the trace of the fusion error covariance matrix, the asynchronous multisensor data fusion algorithm is presented. The multisensor track fusion is valid for asynchronous sensors as well as synchronous sensors. The algorithm makes up for the drawback that asynchronous fusion is limited to one-one sensors fusion. Significantly, the extensive multisensor asynchronous sensor fusion model is established. The analyse of algorithm in the theoretical deduction is presented. The format of algorithm is concise and applicable. Finally, simulation results show the asynchronous mulitsensor fusion is effective and the performance of the model is superior to that of single sensor.
Due to the reasons of sensors in itself and the communication delays, the research of the asynchronous multisensor data fusion problem is more practical than that of synchronous one. Based on minimizing the trace of the fusion error covariance matrix, the asynchronous multisensor data fusion algorithm is presented. The multisensor track fusion is valid for asynchronous sensors as well as synchronous sensors. The algorithm makes up for the drawback that asynchronous fusion is limited to one-one sensors fusion. Significantly, the extensive multisensor asynchronous sensor fusion model is established. The analyse of algorithm in the theoretical deduction is presented. The format of algorithm is concise and applicable. Finally, simulation results show the asynchronous mulitsensor fusion is effective and the performance of the model is superior to that of single sensor.
2006, 28(9): 1550-1554.
Abstract:
A new algorithm to extract accurate contours of multiple moving objects is proposed in this paper. The main contributions of this paper include two parts: firstly, exponential filter is used to calculate the gradient magnitude of color image and the localization accuracy of local maximum of gradient in color image is increased, the gradient magnitude and the motion edges are used subsequently in contour iteration to prevent the contour from shrinking successfully; secondly, the directions of contour are used to prevent the active contour from expanding effectively. As a result, the real compact contours would be extracted automatically by using this algorithm. The experiments show the high efficiency of this algorithm for contours extraction of moving objects from color image sequence with complex background.
A new algorithm to extract accurate contours of multiple moving objects is proposed in this paper. The main contributions of this paper include two parts: firstly, exponential filter is used to calculate the gradient magnitude of color image and the localization accuracy of local maximum of gradient in color image is increased, the gradient magnitude and the motion edges are used subsequently in contour iteration to prevent the contour from shrinking successfully; secondly, the directions of contour are used to prevent the active contour from expanding effectively. As a result, the real compact contours would be extracted automatically by using this algorithm. The experiments show the high efficiency of this algorithm for contours extraction of moving objects from color image sequence with complex background.
2006, 28(9): 1555-1559.
Abstract:
Indeterminacies in amplitude and permutation are the two main cumbersome aspects in frequency domain blind signal separation. A correlation theory between neighbour frequency bins is developed in this paper. It is found that the correlation between neighbor frequency bins of single underwater acoustic signal is strong and stable, while it is very weak in the case of two different signals. Based on these correlation characters, a novel blind source separation method is developed, which can get rid of the permutation indeterminacy. Simulation experiments prove that convolution mixed underwater acoustic signals can be well separated by this method.
Indeterminacies in amplitude and permutation are the two main cumbersome aspects in frequency domain blind signal separation. A correlation theory between neighbour frequency bins is developed in this paper. It is found that the correlation between neighbor frequency bins of single underwater acoustic signal is strong and stable, while it is very weak in the case of two different signals. Based on these correlation characters, a novel blind source separation method is developed, which can get rid of the permutation indeterminacy. Simulation experiments prove that convolution mixed underwater acoustic signals can be well separated by this method.
2006, 28(9): 1560-1564.
Abstract:
The iterative-filtering formula of APC is derived in this paper. The convergence performances of the closed-loop scheme are analysised, and the preprocess method for enhancing convergence rate is proposed. The concept of polarization gain map is proposed. For the case of more Jammers with different polarizations, the performance of APC and full-adaptive polarizatioin array are analysised and compared. Finally, the simulation on the computer validates the scheme and conclusions in the paper.
The iterative-filtering formula of APC is derived in this paper. The convergence performances of the closed-loop scheme are analysised, and the preprocess method for enhancing convergence rate is proposed. The concept of polarization gain map is proposed. For the case of more Jammers with different polarizations, the performance of APC and full-adaptive polarizatioin array are analysised and compared. Finally, the simulation on the computer validates the scheme and conclusions in the paper.
2006, 28(9): 1565-1568.
Abstract:
A vital issue in speech processing is to extract source speeches from noisy mixtures. A method is presented based on wavelet transform and independent component analysis in this paper. Firstly, de-noise the noisy mixtures with discrete wavelet transform. Secondly, get them separated by independent component analysis. Finally, do the post-processing to the separated signals, then the estimated source speeches are got. Simulation results exhibit a high level of separating performance.
A vital issue in speech processing is to extract source speeches from noisy mixtures. A method is presented based on wavelet transform and independent component analysis in this paper. Firstly, de-noise the noisy mixtures with discrete wavelet transform. Secondly, get them separated by independent component analysis. Finally, do the post-processing to the separated signals, then the estimated source speeches are got. Simulation results exhibit a high level of separating performance.
2006, 28(9): 1569-1572.
Abstract:
In this paper, an advanced method in precisely computing of yaw-angle in space-borne Synthetic Aperture Radar (SAR) system is proposed in detail. Standard elliptical orbit model as well as earth ellipsoid model is assumed in the course of development, thus the bias caused by conventional approximation is eliminated. The result of this paper is popular for different kind of space-borne SAR system. A simple algorithm suitable to fast computation for space-born SAR system is also exploited in this paper. The result of simulation in condition of TerraSAR-X system is given in the end. By using the computing method of this paper, emendation error after yaw-steering can be reduced to centesimal Hz level. Thus, precise computation of yaw-steering is successfully achieved.
In this paper, an advanced method in precisely computing of yaw-angle in space-borne Synthetic Aperture Radar (SAR) system is proposed in detail. Standard elliptical orbit model as well as earth ellipsoid model is assumed in the course of development, thus the bias caused by conventional approximation is eliminated. The result of this paper is popular for different kind of space-borne SAR system. A simple algorithm suitable to fast computation for space-born SAR system is also exploited in this paper. The result of simulation in condition of TerraSAR-X system is given in the end. By using the computing method of this paper, emendation error after yaw-steering can be reduced to centesimal Hz level. Thus, precise computation of yaw-steering is successfully achieved.
2006, 28(9): 1573-1576.
Abstract:
In this paper, the ground moving target indication based on modified along-track interferometry of spaceborne parasitic radar system is analyzed. The imaging simulation of a piece of fluctuant terrain with a moving target verifies the validity. The appropriate formation fling parameters are presented when considering some performance metrics, such as the blind velocity, the minimum detectable velocity and the velocity precision. Some conclusions are serviceable of orbital design. Finally, GMTI performance of two typical systems, Cartwheel and Pendulum, is analyzed through computer simulation.
In this paper, the ground moving target indication based on modified along-track interferometry of spaceborne parasitic radar system is analyzed. The imaging simulation of a piece of fluctuant terrain with a moving target verifies the validity. The appropriate formation fling parameters are presented when considering some performance metrics, such as the blind velocity, the minimum detectable velocity and the velocity precision. Some conclusions are serviceable of orbital design. Finally, GMTI performance of two typical systems, Cartwheel and Pendulum, is analyzed through computer simulation.
2006, 28(9): 1577-1581.
Abstract:
A high-resolution subaperture imaging algorithm incorporated with the correction of 2-D image geometric distortion and the compensation of spatially-variant phase error for high squint airborne synthetic aperture radar is presented. Each subaperture processing is based on linear range-Doppler algorithm. According to the basic theory of rotating-object imaging, a methodology is developed to realize the range and Doppler alignment of the corresponding scatterers in successive subimages by the geographical coordinate transforming and positioning, while the step transform technique based on SPECAN is employed to obtain the high-resolution image. The point-target simulations and live data processing results show the validity of the proposed approach.
A high-resolution subaperture imaging algorithm incorporated with the correction of 2-D image geometric distortion and the compensation of spatially-variant phase error for high squint airborne synthetic aperture radar is presented. Each subaperture processing is based on linear range-Doppler algorithm. According to the basic theory of rotating-object imaging, a methodology is developed to realize the range and Doppler alignment of the corresponding scatterers in successive subimages by the geographical coordinate transforming and positioning, while the step transform technique based on SPECAN is employed to obtain the high-resolution image. The point-target simulations and live data processing results show the validity of the proposed approach.
2006, 28(9): 1582-1585.
Abstract:
Design of two-channels high-range-resolution pulse to pulse frequency shifting RCS outdoor measurement radar is researched. A waveform design and a system realization method are presented. The numerical relationship between range-profiles distortion and frequency is analyzed. A method to calculate the targets radial velocity by the measurement results is discussed based on the architecture that the radar can measure the target on two different frequency band at the same time. The targets radial velocity effect on range profile can be corrected. The method is used to process the real outdoor measured data. The amplitude of the targets imaging is boosted and the major lobe of the targets imaging become narrower after being corrected.
Design of two-channels high-range-resolution pulse to pulse frequency shifting RCS outdoor measurement radar is researched. A waveform design and a system realization method are presented. The numerical relationship between range-profiles distortion and frequency is analyzed. A method to calculate the targets radial velocity by the measurement results is discussed based on the architecture that the radar can measure the target on two different frequency band at the same time. The targets radial velocity effect on range profile can be corrected. The method is used to process the real outdoor measured data. The amplitude of the targets imaging is boosted and the major lobe of the targets imaging become narrower after being corrected.
2006, 28(9): 1586-1589.
Abstract:
This paper presents a new SAR Doppler slope filters method for detecting the cross range velocity of moving target. This method builds the Doppler slope filter group recursively and reduces the amount of operations. By analysis on the detection precision and range of target speed, the advantage and the limit of this method are indicated. The detection results from real data demonstrate the accuracy of the conclusion.
This paper presents a new SAR Doppler slope filters method for detecting the cross range velocity of moving target. This method builds the Doppler slope filter group recursively and reduces the amount of operations. By analysis on the detection precision and range of target speed, the advantage and the limit of this method are indicated. The detection results from real data demonstrate the accuracy of the conclusion.
2006, 28(9): 1590-1593.
Abstract:
In order to reduce the effect of speckle on classification and detection, the polarimetric synthetic aperture radar imagery should be preprocessed to suppress speckle. The Polarimetric Whitening Filter (PWF) is efficient in speckle suppression by using complex data of three polarimetric channels. Nevertheless, it only outputs one channel of data. In this paper, a method called Multi-Channel Polarimetric Whitening Filter (MCPWF) is presented. It maintains the optimal speckle reduction performance of the PWF, and three polarimetric channels of output are obtained as well, so that fully polarimetric data can also be used in advanced processing. The effectiveness of the MCPWF is verified through experimental results of Pi-SAR data.
In order to reduce the effect of speckle on classification and detection, the polarimetric synthetic aperture radar imagery should be preprocessed to suppress speckle. The Polarimetric Whitening Filter (PWF) is efficient in speckle suppression by using complex data of three polarimetric channels. Nevertheless, it only outputs one channel of data. In this paper, a method called Multi-Channel Polarimetric Whitening Filter (MCPWF) is presented. It maintains the optimal speckle reduction performance of the PWF, and three polarimetric channels of output are obtained as well, so that fully polarimetric data can also be used in advanced processing. The effectiveness of the MCPWF is verified through experimental results of Pi-SAR data.
2006, 28(9): 1594-1597.
Abstract:
Target feature-enhanced processing of SAR image is meaningful to SAR ATR. One regularization method based on lk norm used for target feature-enhanced of SAR image is discussed in this paper. This method exploits the useful prior information which is well consistent to the statistically property of SAR image, makes up the additional constraint condition, turns the problem of target feature-enhanced processing of SAR image into the simple-formed optimization problem. A fast iterative algorithm is proposed to solve the optimization problem. The Simulation results and computational results of measured data prove its validity.
Target feature-enhanced processing of SAR image is meaningful to SAR ATR. One regularization method based on lk norm used for target feature-enhanced of SAR image is discussed in this paper. This method exploits the useful prior information which is well consistent to the statistically property of SAR image, makes up the additional constraint condition, turns the problem of target feature-enhanced processing of SAR image into the simple-formed optimization problem. A fast iterative algorithm is proposed to solve the optimization problem. The Simulation results and computational results of measured data prove its validity.
2006, 28(9): 1598-1602.
Abstract:
In theory, the Ground Moving Target Indication (GMTI) method of space based sparse array Scanned Pattern Interferometric Radar (SPIR) only works when there are no ambiguities in azimuth. By decomposing the Point Spread Function (PSF) matrix, It is proposed that SPIR can work even there are a few ambiguities in azimuth, i.e. the ground scene can be recovered to some degree. Also through simulation experiments, SPIR is found to get much better GMTI performance than that of general space-time cascade processing.
In theory, the Ground Moving Target Indication (GMTI) method of space based sparse array Scanned Pattern Interferometric Radar (SPIR) only works when there are no ambiguities in azimuth. By decomposing the Point Spread Function (PSF) matrix, It is proposed that SPIR can work even there are a few ambiguities in azimuth, i.e. the ground scene can be recovered to some degree. Also through simulation experiments, SPIR is found to get much better GMTI performance than that of general space-time cascade processing.
2006, 28(9): 1603-1606.
Abstract:
In this paper, a modified method is proposed to estimate the Direction Of Arrival (DOA) and Degree Of Polarization (DOP) of Partially Polarized (PP) electromagnetic waves. This method makes full use of the eigenvalues and eigenvectors of matrix, which results in automatic combination of parameters, reduction of computation and improvement of precision. Finally, the simulation results are provided to demonstrate the effectiveness of the new algorithm.
In this paper, a modified method is proposed to estimate the Direction Of Arrival (DOA) and Degree Of Polarization (DOP) of Partially Polarized (PP) electromagnetic waves. This method makes full use of the eigenvalues and eigenvectors of matrix, which results in automatic combination of parameters, reduction of computation and improvement of precision. Finally, the simulation results are provided to demonstrate the effectiveness of the new algorithm.
2006, 28(9): 1607-1610.
Abstract:
The paper presents an algorithm based on classification and 3D-SPIHT for 17 bands multispectral images compression. First, the 3D transform for the image data is used with CDF97 wavelet to move spacial correlation and classification prediction to move spectral correlation. Second, according to remain image coefficients from classification prediction, the method realizes compression coding by 3D-SPIHT and adopts Huffman coding files to do the lossless coding of codebook and index table. Meanwhile it transmits all coding files to the decoding so as to reconstruct image. The results of numerous experiments indicate the quality of reconstructive image.
The paper presents an algorithm based on classification and 3D-SPIHT for 17 bands multispectral images compression. First, the 3D transform for the image data is used with CDF97 wavelet to move spacial correlation and classification prediction to move spectral correlation. Second, according to remain image coefficients from classification prediction, the method realizes compression coding by 3D-SPIHT and adopts Huffman coding files to do the lossless coding of codebook and index table. Meanwhile it transmits all coding files to the decoding so as to reconstruct image. The results of numerous experiments indicate the quality of reconstructive image.
2006, 28(9): 1611-1613.
Abstract:
A new type of radar waveform called Linear Contracting Waveform is presented. To suppress the sidelobe of such waveforms matched output , a digital filter is adopted. The simulation results show that , for the range ambiguity function of such waveform, the peak sidelobe is -18~-20dB,and the 4dB mainlobe width is only 54~70 percent of that of the linear frequency modulated (LFM) signal with the same parameters. Filtering the compressed form of such waveform by the improved digital sidelobe suppression filter, the output signals peak sidelobe level is as low as -50dB, and the mainlobe width is only unit sample length.
A new type of radar waveform called Linear Contracting Waveform is presented. To suppress the sidelobe of such waveforms matched output , a digital filter is adopted. The simulation results show that , for the range ambiguity function of such waveform, the peak sidelobe is -18~-20dB,and the 4dB mainlobe width is only 54~70 percent of that of the linear frequency modulated (LFM) signal with the same parameters. Filtering the compressed form of such waveform by the improved digital sidelobe suppression filter, the output signals peak sidelobe level is as low as -50dB, and the mainlobe width is only unit sample length.
2006, 28(9): 1614-1617.
Abstract:
The principle of Discrete Evolutionary Transform(DET) and Discrete Evolutionary Hough Transform(DEHT) are introduced. The method of excising multi-component FM interference for pseudo-random coded fuze system based on DEHT is analyzed in detail. The instantaneous phase of interference is firstly estimated with DEHT and the estimated phase error is decreased through recursive correcting. An adaptive time-varying filter based on the estimated instantaneous phase is set up to excise the interference one by one. The correlator output in different ISR situations is simulated. It is found by simulation that the method can effectively excise the interference and improve the correlator output.
The principle of Discrete Evolutionary Transform(DET) and Discrete Evolutionary Hough Transform(DEHT) are introduced. The method of excising multi-component FM interference for pseudo-random coded fuze system based on DEHT is analyzed in detail. The instantaneous phase of interference is firstly estimated with DEHT and the estimated phase error is decreased through recursive correcting. An adaptive time-varying filter based on the estimated instantaneous phase is set up to excise the interference one by one. The correlator output in different ISR situations is simulated. It is found by simulation that the method can effectively excise the interference and improve the correlator output.
2006, 28(9): 1618-1621.
Abstract:
Upper union bounds of turbo codes for maximal ratio combining (MRC) diversity systems are presented in this paper. The simplified expression of error integral function is used to derive the precise expressions of pairwise error probability for MRC receivers wherein the probabilities of slow fading multichannel come from different distribution families. The numerical analysis and simulations performed over Rayleigh channel demonstrate that the theoretical analysis conforms to the simulations. It is concluded that the derived expressions can be generally used for the performance estimation of MRC multichannel receivers with different fading statistics.
Upper union bounds of turbo codes for maximal ratio combining (MRC) diversity systems are presented in this paper. The simplified expression of error integral function is used to derive the precise expressions of pairwise error probability for MRC receivers wherein the probabilities of slow fading multichannel come from different distribution families. The numerical analysis and simulations performed over Rayleigh channel demonstrate that the theoretical analysis conforms to the simulations. It is concluded that the derived expressions can be generally used for the performance estimation of MRC multichannel receivers with different fading statistics.
2006, 28(9): 1622-1625.
Abstract:
Vertical Bell Labs Layered Space Time (V-BLAST) scheme improves greatly system channel capacity, however multi-transmit antennas introduce space interference, which degrades sharply BER (FER) performance. In order to overcome effectively the space interference, an iterative ordered Zero-Forcing Hybird Interference Cancellation (ZF-HIC) algorithm is adopted. Compared to conventional Zero-Forcing Serial Interference Cancellation (ZF-SIC) algortithm, ZF-HIC provides better BER and FER performance with a lower computational complexity. Soft-information after ZF-HIC detector is sent to Turbo iterative decoding and the resulting hard decision-information can be sent back to V-BLAST detector again to further update and improve the performance of ZF-HIC detector. So, the Turbo V-BLAST has the double-iterated concatenated decoding structure. The simulation results are presented to verify its advantages.
Vertical Bell Labs Layered Space Time (V-BLAST) scheme improves greatly system channel capacity, however multi-transmit antennas introduce space interference, which degrades sharply BER (FER) performance. In order to overcome effectively the space interference, an iterative ordered Zero-Forcing Hybird Interference Cancellation (ZF-HIC) algorithm is adopted. Compared to conventional Zero-Forcing Serial Interference Cancellation (ZF-SIC) algortithm, ZF-HIC provides better BER and FER performance with a lower computational complexity. Soft-information after ZF-HIC detector is sent to Turbo iterative decoding and the resulting hard decision-information can be sent back to V-BLAST detector again to further update and improve the performance of ZF-HIC detector. So, the Turbo V-BLAST has the double-iterated concatenated decoding structure. The simulation results are presented to verify its advantages.
2006, 28(9): 1626-1629.
Abstract:
In order to improve the performance of Quasi-Orthogonal SpaceTime Block Code(QO-STBC), a Random-Rotation QO-STBC(RR-QO-STBC) is proposed. This transmission diversity scheme randomly rotates every information symbol vector, thus the inter-symbol interference between multi-antennas of QO-STBC is randomized and alleviated. Simulation results suggest, in 41 MIMO QPSK modulation system, under the ML detection rule，the proposed scheme outperforms the conventional QO-STBC about 4dB when the BER is 10-5, and also better than ST-LCP 0.51dB when the BER is below 10-4; The new scheme owns similar performance with the CFR scheme when SNR is above 16dB. The performance loss due to the limitation of number of random-rotation matrixes in the practical scenario is investigated. When the number of matrixes is greater than 16, the performance loss is negligible.
In order to improve the performance of Quasi-Orthogonal SpaceTime Block Code(QO-STBC), a Random-Rotation QO-STBC(RR-QO-STBC) is proposed. This transmission diversity scheme randomly rotates every information symbol vector, thus the inter-symbol interference between multi-antennas of QO-STBC is randomized and alleviated. Simulation results suggest, in 41 MIMO QPSK modulation system, under the ML detection rule，the proposed scheme outperforms the conventional QO-STBC about 4dB when the BER is 10-5, and also better than ST-LCP 0.51dB when the BER is below 10-4; The new scheme owns similar performance with the CFR scheme when SNR is above 16dB. The performance loss due to the limitation of number of random-rotation matrixes in the practical scenario is investigated. When the number of matrixes is greater than 16, the performance loss is negligible.
2006, 28(9): 1630-1635.
Abstract:
Ultra Wide-Band(VWB) communication is the focus of the research of wireless communication. Impulse radio (IR)is one of the most important technology of UWB with data rate higher than 100Mbps and it has ultrawide frequency span and ultra low power spectra density. The timing recovery and pulse synchronization are the most critical problems of IR. In this paper, anovel mechanism based on orthogonal decomposition is proposed for joint timing recovering and multi-path components detection. Simulation shows that the algorithm has good performance on multi-path components detection, pulse repetition period estimation and timing recovery in dense multi-path environment with heavy ISI.
Ultra Wide-Band(VWB) communication is the focus of the research of wireless communication. Impulse radio (IR)is one of the most important technology of UWB with data rate higher than 100Mbps and it has ultrawide frequency span and ultra low power spectra density. The timing recovery and pulse synchronization are the most critical problems of IR. In this paper, anovel mechanism based on orthogonal decomposition is proposed for joint timing recovering and multi-path components detection. Simulation shows that the algorithm has good performance on multi-path components detection, pulse repetition period estimation and timing recovery in dense multi-path environment with heavy ISI.
2006, 28(9): 1636-1639.
Abstract:
A 2-D shooting-and-bouncing ray-tracing (SBR) method is used to analyze the different antenna array structures effect on the capacity CCDF of indoor NLOS MIMO channel. The results show in NLOS indoor environments the less antenna interval is, the less MIMO channel capacities get. The results on 10% outage capacity show that there exist a fixed relationship that i.i.d Rayleigh channel capacity is larger than the capacity with linear antenna array which is larger than the capacity with rectangular antenna array or with circular antenna array. When antenna interval is equal to or larger than 3, antennas array structures affect the CCDF indistinctively and all the CCDF approach the theoretical i.i.d Rayleigh capacity, i.e. Telatar capacity. When antenna interval is equal to or less than 1, the CCDFS of MIMO system equipped with different antenna array structures changes remarkably. To obtain the MIMO capacity gains in indoor NLOS environment, antenna interval and antenna structure should be considered jointly when designing the antenna array.
A 2-D shooting-and-bouncing ray-tracing (SBR) method is used to analyze the different antenna array structures effect on the capacity CCDF of indoor NLOS MIMO channel. The results show in NLOS indoor environments the less antenna interval is, the less MIMO channel capacities get. The results on 10% outage capacity show that there exist a fixed relationship that i.i.d Rayleigh channel capacity is larger than the capacity with linear antenna array which is larger than the capacity with rectangular antenna array or with circular antenna array. When antenna interval is equal to or larger than 3, antennas array structures affect the CCDF indistinctively and all the CCDF approach the theoretical i.i.d Rayleigh capacity, i.e. Telatar capacity. When antenna interval is equal to or less than 1, the CCDFS of MIMO system equipped with different antenna array structures changes remarkably. To obtain the MIMO capacity gains in indoor NLOS environment, antenna interval and antenna structure should be considered jointly when designing the antenna array.
2006, 28(9): 1640-1644.
Abstract:
In an achieving near-capacity V-BLAST turbo receiver, Soft-In/Soft-Out (SISO) signal detector is needed. Minimum Mean Square Error (MMSE) iterative soft interference canceller is a popular SISO detector in such system. Link adaptation is a good scheme to improve performance in wireless system. In the paper, a modification of MMSE iterative soft interference cancellation detector is presented for variable transmission power, and an effective transmit power scheme is proposed to decrease Bit Error Rate (BER). This scheme requires small feedback overhead. By simulation of uncoded V-BLAST system with 4 transmit antennas and 4 receive antennas, it is proved that if the performance requirement of BER=10-3, the modified V-BLAST system with transmit power allocation outperforms the conventional V-BLAST system about 2dB when QPSK modulation is used and iterative number of detection equals 2. When 16QAM is used, the proposed scheme outperforms the conventional scheme about 6dB.
In an achieving near-capacity V-BLAST turbo receiver, Soft-In/Soft-Out (SISO) signal detector is needed. Minimum Mean Square Error (MMSE) iterative soft interference canceller is a popular SISO detector in such system. Link adaptation is a good scheme to improve performance in wireless system. In the paper, a modification of MMSE iterative soft interference cancellation detector is presented for variable transmission power, and an effective transmit power scheme is proposed to decrease Bit Error Rate (BER). This scheme requires small feedback overhead. By simulation of uncoded V-BLAST system with 4 transmit antennas and 4 receive antennas, it is proved that if the performance requirement of BER=10-3, the modified V-BLAST system with transmit power allocation outperforms the conventional V-BLAST system about 2dB when QPSK modulation is used and iterative number of detection equals 2. When 16QAM is used, the proposed scheme outperforms the conventional scheme about 6dB.
2006, 28(9): 1645-1648.
Abstract:
An OFDM system with 16DAPSK modulation for each subcarrier is considered. In this paper, a novel bit soft-output demodulation decoding scheme which is simpler to implement for coded 16DAPSK signal is proposed and investigated. The simulation results show that about 1.2dB performance gain can be achieved in AWGN, flat Rayleigh fading, and multipath Rayleigh fading channels with forward error correct coding (rate 3/4, punctured convolutional coding) compared with hard-decision decoding. The Bit-Error-Rate (BER) will be reduced if this method is applied in 100Mbps 16DAPSK-OFDM millimeter-wave broadband mobile access experimental system developed by CRL in Japan.
An OFDM system with 16DAPSK modulation for each subcarrier is considered. In this paper, a novel bit soft-output demodulation decoding scheme which is simpler to implement for coded 16DAPSK signal is proposed and investigated. The simulation results show that about 1.2dB performance gain can be achieved in AWGN, flat Rayleigh fading, and multipath Rayleigh fading channels with forward error correct coding (rate 3/4, punctured convolutional coding) compared with hard-decision decoding. The Bit-Error-Rate (BER) will be reduced if this method is applied in 100Mbps 16DAPSK-OFDM millimeter-wave broadband mobile access experimental system developed by CRL in Japan.
2006, 28(9): 1649-1653.
Abstract:
The incremental redundancy hybrid ARQ scheme can provide high throughput efficiency. Meanwhile, it also leads to high transmission delay. This paper presents a Low-Delay Incremental Redundancy hybrid ARQ scheme with Adaptive Modulation (AM-LD-IR). It adopts different strategy of incremental redundancy and constellation size according to the received Signal-to-Noise Ratio (SNR). The calculation and simulation results in the paper show, comparing to the ordinary incremental redundancy hybrid ARQ systems with adaptive modulation, the AM-LD-IR system can provide a little higher throughput efficiency and can reduce much transmission delay.
The incremental redundancy hybrid ARQ scheme can provide high throughput efficiency. Meanwhile, it also leads to high transmission delay. This paper presents a Low-Delay Incremental Redundancy hybrid ARQ scheme with Adaptive Modulation (AM-LD-IR). It adopts different strategy of incremental redundancy and constellation size according to the received Signal-to-Noise Ratio (SNR). The calculation and simulation results in the paper show, comparing to the ordinary incremental redundancy hybrid ARQ systems with adaptive modulation, the AM-LD-IR system can provide a little higher throughput efficiency and can reduce much transmission delay.
2006, 28(9): 1654-1658.
Abstract:
A novel voice / data call admission control algorithm based on call buffer in wireless networks is presented in this paper, which is charactered by dual thresholds with queueing for Variable Bit-Rate Data Traffic call ( DTQ-VBR ). The algorithm gives attention to the VBR character of data traffic and can adapt its service bandwidth through different settings of the thresholds and the call buffer size. Theoretical performance analysis is made by using three dimensions Markovian chain, and it is also shown that compared with DTR-Q and DTBR algorithm, the performances of the presented algorithm such as average channel utility, call dropping probability and block probability can be improved significantly according to a number of simulations.
A novel voice / data call admission control algorithm based on call buffer in wireless networks is presented in this paper, which is charactered by dual thresholds with queueing for Variable Bit-Rate Data Traffic call ( DTQ-VBR ). The algorithm gives attention to the VBR character of data traffic and can adapt its service bandwidth through different settings of the thresholds and the call buffer size. Theoretical performance analysis is made by using three dimensions Markovian chain, and it is also shown that compared with DTR-Q and DTBR algorithm, the performances of the presented algorithm such as average channel utility, call dropping probability and block probability can be improved significantly according to a number of simulations.
2006, 28(9): 1659-1662.
Abstract:
A simple and efficient iterative control algorithm is proposed. An iterative degree vector about SNR is firstly derived by analysis of extrinsic information transfer chart, iterative control is then implemented by selecting the relevant value according to estimated SNR. Simple in realization and high in performance, this method can be utilized in performance analysis.
A simple and efficient iterative control algorithm is proposed. An iterative degree vector about SNR is firstly derived by analysis of extrinsic information transfer chart, iterative control is then implemented by selecting the relevant value according to estimated SNR. Simple in realization and high in performance, this method can be utilized in performance analysis.
2006, 28(9): 1663-1665.
Abstract:
Optical Burst Switching (OBS) is a promising paradigm for the next-generation Internet. In this paper, a threshold-based data channel scheduling algorithm is proposed, which uses LAUC to schedule long burst and uses LAUC-VF to schedule short burst. Simulation results show that the scheduling time of the proposed algorithm is close to LAUC, and the performance of data burst loss probability is better than LAUC-VF.
Optical Burst Switching (OBS) is a promising paradigm for the next-generation Internet. In this paper, a threshold-based data channel scheduling algorithm is proposed, which uses LAUC to schedule long burst and uses LAUC-VF to schedule short burst. Simulation results show that the scheduling time of the proposed algorithm is close to LAUC, and the performance of data burst loss probability is better than LAUC-VF.
2006, 28(9): 1666-1669.
Abstract:
A new method is proposed to replace face algorithm used in location-based routing protocols. The proposed routing and Greedy Perimeter Stateless Routing (GPSR) are evaluated by NS. Performance results reveal that the new routing protocol performs better than the GPSR in term of average end-to-end delay, aggregate throughput and average delivery success rate.
A new method is proposed to replace face algorithm used in location-based routing protocols. The proposed routing and Greedy Perimeter Stateless Routing (GPSR) are evaluated by NS. Performance results reveal that the new routing protocol performs better than the GPSR in term of average end-to-end delay, aggregate throughput and average delivery success rate.
2006, 28(9): 1670-1674.
Abstract:
A new Fuzzy-logic based Dynamic Resource Allocation algorithm (FDRA) used for QoS control is proposed in this paper. In the hierarchically distributed architecture with multiple Bandwidth Brokers (BB), using sliding window and sliding pointer based mechanism, when the allocated resource is in short, a request is issued by the distributed BB to the centralized BB for additional resource. When the resource kept by a distributed BB is over the actual need to some extent, some allocated resource will be released with hysteresis. The size of additional allocated resource and released resource is determined by the centralized BB and the distributed BB respectively. The determination is concluded with a fuzzy logic algorithm taking into account of the current network load status. In order to improve the effectiveness of the decision, a new method of fuzzy mapping function generation is proposed, which is based on the statistical characteristics of the data sources. Simulation results show that the proposed algorithm is superior to the existing ones.
A new Fuzzy-logic based Dynamic Resource Allocation algorithm (FDRA) used for QoS control is proposed in this paper. In the hierarchically distributed architecture with multiple Bandwidth Brokers (BB), using sliding window and sliding pointer based mechanism, when the allocated resource is in short, a request is issued by the distributed BB to the centralized BB for additional resource. When the resource kept by a distributed BB is over the actual need to some extent, some allocated resource will be released with hysteresis. The size of additional allocated resource and released resource is determined by the centralized BB and the distributed BB respectively. The determination is concluded with a fuzzy logic algorithm taking into account of the current network load status. In order to improve the effectiveness of the decision, a new method of fuzzy mapping function generation is proposed, which is based on the statistical characteristics of the data sources. Simulation results show that the proposed algorithm is superior to the existing ones.
2006, 28(9): 1675-1678.
Abstract:
The functional architectures of connectionless and connection-oriented transport networks are compared and the conception and features of flow are introduced. And based on the functional architecture of connectionless transport network, a generic management information model is defined, which is protocol-neutral, and described in UML format along with detailed managed object descriptions in aspects of behavior, attribute, notification and entity relationship.
The functional architectures of connectionless and connection-oriented transport networks are compared and the conception and features of flow are introduced. And based on the functional architecture of connectionless transport network, a generic management information model is defined, which is protocol-neutral, and described in UML format along with detailed managed object descriptions in aspects of behavior, attribute, notification and entity relationship.
2006, 28(9): 1679-1683.
Abstract:
A lot of research work has been done for conformance testing of protocols based on the FSM model. After a fault has been detected, it arises the problem that how to diagnose the fault. In this paper, it is assumed that IUT (Implementation Under Testing) exists only one single fault and a fault diagnosis algorithm is proposed. The diagnosis algorithm makes full use of transitions confirmed to be correct and head states set of the next observed input/output pair to the symptom transition and guarantees the diagnostic of any single fault in an FSM. In this paper, the comparison of time complexity with other existing fault diagnosis algorithms is given and an example to demonstrate the algorithm is presented.
A lot of research work has been done for conformance testing of protocols based on the FSM model. After a fault has been detected, it arises the problem that how to diagnose the fault. In this paper, it is assumed that IUT (Implementation Under Testing) exists only one single fault and a fault diagnosis algorithm is proposed. The diagnosis algorithm makes full use of transitions confirmed to be correct and head states set of the next observed input/output pair to the symptom transition and guarantees the diagnostic of any single fault in an FSM. In this paper, the comparison of time complexity with other existing fault diagnosis algorithms is given and an example to demonstrate the algorithm is presented.
2006, 28(9): 1684-1688.
Abstract:
At the network layer, several constraints must be taken into account when calculating multicast routing and wavelength assignment. The constraints mainly include the following four aspects: sparse light splitter constraints, wavelength continuity constraints in WDM optical network, power budget constraints and sparse wavelength convert constraints. So far, most papers analyzed only one or two of these constraints respectively. This paper illuminates these constraints in detail first and then brings forward a heuristic algorithm with multiple constraints. Finally, designs two simulations on CERNET and NSFNET network topology. The results of the two simulations indicate the validity and feasibility of the algorithm.
At the network layer, several constraints must be taken into account when calculating multicast routing and wavelength assignment. The constraints mainly include the following four aspects: sparse light splitter constraints, wavelength continuity constraints in WDM optical network, power budget constraints and sparse wavelength convert constraints. So far, most papers analyzed only one or two of these constraints respectively. This paper illuminates these constraints in detail first and then brings forward a heuristic algorithm with multiple constraints. Finally, designs two simulations on CERNET and NSFNET network topology. The results of the two simulations indicate the validity and feasibility of the algorithm.
2006, 28(9): 1689-1692.
Abstract:
In order to obtain Integrated and consistent segmentation of motion video objects, the segmentation algorithm based on fuzzy clustering is used to obtain pixels that constitute boundaries of motion object and extract video objects in the sequence sequentially. The motion properties of the current frame in each wavelet sub-band first are calculated using information of current frame and some frames before it in this algorithm. The set of motion eigenvectors is constructed with these properties. Then, significant change pixels are separated by fuzzy C-mean clustering algorithm based on these motion eigenvectors of low-resolution image. The change detection mash of motion object is obtained with significant change image, instead of frame difference, by conventional method of change detection and video objects are extracted. At the same time, the mean absolute different between consecutive two frames is used to determine number of frames that are used for properties calculation. It ensures accuracy of video objects obtained,. The experimental results demonstrate the algorithm effective.
In order to obtain Integrated and consistent segmentation of motion video objects, the segmentation algorithm based on fuzzy clustering is used to obtain pixels that constitute boundaries of motion object and extract video objects in the sequence sequentially. The motion properties of the current frame in each wavelet sub-band first are calculated using information of current frame and some frames before it in this algorithm. The set of motion eigenvectors is constructed with these properties. Then, significant change pixels are separated by fuzzy C-mean clustering algorithm based on these motion eigenvectors of low-resolution image. The change detection mash of motion object is obtained with significant change image, instead of frame difference, by conventional method of change detection and video objects are extracted. At the same time, the mean absolute different between consecutive two frames is used to determine number of frames that are used for properties calculation. It ensures accuracy of video objects obtained,. The experimental results demonstrate the algorithm effective.
2006, 28(9): 1693-1696.
Abstract:
In this paper, an iterative multiuser detection algorithm using partial soft interfenrence cancellation based on detection reliability is proposed. If the a priori information of the transmitted symbols provided by the channel decoder in the previous iteration is larger than a predefined threshold , the detection of these symbols are thought to be reliable and the corresponding MAI (Multiuser Access Interfenrence) can be eliminated from the outputs of the matched filters. This is equal to decrease the number of the interference users, thus the complexity of the iterative multiuser detection algorithm is decreased. Furthermore, when the MAI is moderate and the SNR is high, the computational complexity of this algorithm can be reduced adaptively.
In this paper, an iterative multiuser detection algorithm using partial soft interfenrence cancellation based on detection reliability is proposed. If the a priori information of the transmitted symbols provided by the channel decoder in the previous iteration is larger than a predefined threshold , the detection of these symbols are thought to be reliable and the corresponding MAI (Multiuser Access Interfenrence) can be eliminated from the outputs of the matched filters. This is equal to decrease the number of the interference users, thus the complexity of the iterative multiuser detection algorithm is decreased. Furthermore, when the MAI is moderate and the SNR is high, the computational complexity of this algorithm can be reduced adaptively.
2006, 28(9): 1697-1702.
Abstract:
OFDM has received a considerable attention for realization of high-speed power line communications. Impulse, one of the main disturbances in power line, is a type of bursty, high amplitude, and low probability noise. Such impulses with very short duration will contain spectral components on all subchannels, and thus impact the decision of symbols transmitted on all subcarriers. This paper analyzes the performance of selected impulse noise detectors. The receiver detects impulse emergence and its position within an OFDM symbol by amplitude calculation combined in time and frequency domain. Samples corrupted by impulse noise are reconstructed using redundancy of the guard band in the frequency domain. Simulation results show that the proposed algorithm has a good performance for low signal-to-noise ratios, if the proper threshold is selected.
OFDM has received a considerable attention for realization of high-speed power line communications. Impulse, one of the main disturbances in power line, is a type of bursty, high amplitude, and low probability noise. Such impulses with very short duration will contain spectral components on all subchannels, and thus impact the decision of symbols transmitted on all subcarriers. This paper analyzes the performance of selected impulse noise detectors. The receiver detects impulse emergence and its position within an OFDM symbol by amplitude calculation combined in time and frequency domain. Samples corrupted by impulse noise are reconstructed using redundancy of the guard band in the frequency domain. Simulation results show that the proposed algorithm has a good performance for low signal-to-noise ratios, if the proper threshold is selected.
2006, 28(9): 1703-1705.
Abstract:
The capacity of MIMO system is increased linearly with the number of the antennas in multi-path fading environments, and transmit/receive antenna selection barters little lost of system performance for great decreasing of RF cost, making MIMO system not fully limited by RF cost. To quickly select transmit/receiver antenna subset making the system capacity best, this paper proposes an adapted algorithm for the fast antenna selection algorithm, which reduces the computation complexity by updating the quantities in real time. Simulation results indicate that the algorithm decreases computation time a lot without any system capacity lost.
The capacity of MIMO system is increased linearly with the number of the antennas in multi-path fading environments, and transmit/receive antenna selection barters little lost of system performance for great decreasing of RF cost, making MIMO system not fully limited by RF cost. To quickly select transmit/receiver antenna subset making the system capacity best, this paper proposes an adapted algorithm for the fast antenna selection algorithm, which reduces the computation complexity by updating the quantities in real time. Simulation results indicate that the algorithm decreases computation time a lot without any system capacity lost.
2006, 28(9): 1706-1709.
Abstract:
The problem on the time-frequency parameters estimation in the mobile channel is considered in this paper. For this aim, a blind algorithm is proposed, which is based on the cyclostationarity property of the received signal. Theoralic analysis and simulation results are provided to show that this algorithm is suitable for a frequency selective fading channel. When compared with the other method, its ability to estimate a larger frequency offset and higher estimation resolution are shown.
The problem on the time-frequency parameters estimation in the mobile channel is considered in this paper. For this aim, a blind algorithm is proposed, which is based on the cyclostationarity property of the received signal. Theoralic analysis and simulation results are provided to show that this algorithm is suitable for a frequency selective fading channel. When compared with the other method, its ability to estimate a larger frequency offset and higher estimation resolution are shown.
2006, 28(9): 1710-1713.
Abstract:
The TDOA/AOA location algorithms based on the Chans algorithm add an AOA error equation on the group of TDOA error equations in the Chans algorithm and resolve these equations by the WLS method. But they assume the abscissa, the ordinate of the MS and the distance between the MS and the severing BS are three independent variables neglecting their correlation. And then operate the WLS method twice with each root has two values. The location error increases according with the increment of the variance of the measurement error of AOA. The proposed algorithm estimates AOA by Kalman filter and simplifies the mentioned three variables into one. So it can get the only root by using the WLS method once and eliminate the ambiguity. The result of simulation proves its simplification, less calculating amount, better location accuracy and robustness.
The TDOA/AOA location algorithms based on the Chans algorithm add an AOA error equation on the group of TDOA error equations in the Chans algorithm and resolve these equations by the WLS method. But they assume the abscissa, the ordinate of the MS and the distance between the MS and the severing BS are three independent variables neglecting their correlation. And then operate the WLS method twice with each root has two values. The location error increases according with the increment of the variance of the measurement error of AOA. The proposed algorithm estimates AOA by Kalman filter and simplifies the mentioned three variables into one. So it can get the only root by using the WLS method once and eliminate the ambiguity. The result of simulation proves its simplification, less calculating amount, better location accuracy and robustness.
2006, 28(9): 1714-1716.
Abstract:
As prior secret sharing can not provide forward-secure. So in this paper a forward secure secret sharing scheme is proposed to achieve security against cheating participants by using multiplicative threshold scheme of Boyd, based on discrete logarithms and the strong RSA assumption. In the scheme participants can update and verify the shares. Security of the scheme is provided under the strong RSA assumption and discrete logarithms.
As prior secret sharing can not provide forward-secure. So in this paper a forward secure secret sharing scheme is proposed to achieve security against cheating participants by using multiplicative threshold scheme of Boyd, based on discrete logarithms and the strong RSA assumption. In the scheme participants can update and verify the shares. Security of the scheme is provided under the strong RSA assumption and discrete logarithms.
2006, 28(9): 1717-1720.
Abstract:
Hash chains are widely used in various cryptographic systems such as electronic micropayments and one-time passwords etc. However, hash chains suffer from the limitation that they have a finite number of links which when used up requires the system to re-initialize new hash chains. So system design has to reduce the overhead when hash chains are re-initialized. An efficient construction which can re-initialize hash chains is proposed, and it is entirely based on one-way hash function. In the proposed construction hash chains can be securely re-initialized in a non-repudiable manner. The method will find much pragmatic application because of its efficient, secure and elegant structure.
Hash chains are widely used in various cryptographic systems such as electronic micropayments and one-time passwords etc. However, hash chains suffer from the limitation that they have a finite number of links which when used up requires the system to re-initialize new hash chains. So system design has to reduce the overhead when hash chains are re-initialized. An efficient construction which can re-initialize hash chains is proposed, and it is entirely based on one-way hash function. In the proposed construction hash chains can be securely re-initialized in a non-repudiable manner. The method will find much pragmatic application because of its efficient, secure and elegant structure.
2006, 28(9): 1721-1726.
Abstract:
Survivability should be considered beyond security for information system, and quantitative analysis can assess system survivability accurately for improvement. Information system is presented by finite state machine and its state transition map is used to describe analysis process, where the hierarchical structure of system state avoids the problem of enumerating states in Markov chain model. Based on SNA method, a framework of quantitative analysis is introduced: defining system, testing systems survivability, computing survivability, and giving analysis report finally, which is easily implemented by computer. In the framework, the event database which is based on event classification and grade makes creating test project automatically and objectively, and survivability is computed through resistance, recognition and recovery in a hierarchical process.
Survivability should be considered beyond security for information system, and quantitative analysis can assess system survivability accurately for improvement. Information system is presented by finite state machine and its state transition map is used to describe analysis process, where the hierarchical structure of system state avoids the problem of enumerating states in Markov chain model. Based on SNA method, a framework of quantitative analysis is introduced: defining system, testing systems survivability, computing survivability, and giving analysis report finally, which is easily implemented by computer. In the framework, the event database which is based on event classification and grade makes creating test project automatically and objectively, and survivability is computed through resistance, recognition and recovery in a hierarchical process.
2006, 28(9): 1727-1730.
Abstract:
Kernel method is introduced to intrusion detection and an anomaly intrusion detection method based on kernel Fisher discriminant is presented in this paper. This method is applied for monitoring the abnormal behavior of processes. Firstly, this paper presents the possible of kernel Fisher method applied to intrusion detection. Secondly, this paper descriptions the kernel Fisher algorithm is generalized for heterogeneous datasets. A model of anomaly intrusion detection based on kernel Fisher is given and the working process of this model is used with sendmail system call in detail discussion; Finally, the simulation result is compared with other methods, The measuring result of this method is superior to other similar methods .
Kernel method is introduced to intrusion detection and an anomaly intrusion detection method based on kernel Fisher discriminant is presented in this paper. This method is applied for monitoring the abnormal behavior of processes. Firstly, this paper presents the possible of kernel Fisher method applied to intrusion detection. Secondly, this paper descriptions the kernel Fisher algorithm is generalized for heterogeneous datasets. A model of anomaly intrusion detection based on kernel Fisher is given and the working process of this model is used with sendmail system call in detail discussion; Finally, the simulation result is compared with other methods, The measuring result of this method is superior to other similar methods .
2006, 28(9): 1731-1734.
Abstract:
Influence of electrical large platform on antennas can not be ignored when designing effective electric system. In this article, a hybrid technique, which combines two current-based method: Method of Moment(MoM) and Physical Optics(PO), is preferred to take the platform effects into account through PO current when solving the antenna by MoM , and the NURBUS-PO is applied further to reduce the complexity of modeling and computation, thereby making it impossible to solve the antenna-platform system through MoM. The analyzing results of MoM and hybrid technique show that the effects of platform is obvious, while the hybrid technique is accurate enough and spare great computational time and storage, providing a good access to solve the EM characters of antennas on electrical large carrier.
Influence of electrical large platform on antennas can not be ignored when designing effective electric system. In this article, a hybrid technique, which combines two current-based method: Method of Moment(MoM) and Physical Optics(PO), is preferred to take the platform effects into account through PO current when solving the antenna by MoM , and the NURBUS-PO is applied further to reduce the complexity of modeling and computation, thereby making it impossible to solve the antenna-platform system through MoM. The analyzing results of MoM and hybrid technique show that the effects of platform is obvious, while the hybrid technique is accurate enough and spare great computational time and storage, providing a good access to solve the EM characters of antennas on electrical large carrier.
2006, 28(9): 1735-1739.
Abstract:
When either electric field integral equation or magnetic field integral equation is employed to analyze electromagnetic scattering of conducting bodies, at some discrete resonance frequencies, the solution of Method Of Moments(MOM) matrix will be nonunique or unstable. In this paper, a new effective method is presented to solve this problem. At the interior resonance frequencies, Inagaki mode method, based on electric field integral equation, is used to filter out resonance modes and obtain right parameters. The proposed method possesses the merits of clarity in concept and simplicity in computation. A good agreement is achieved between the calculated results and the published as well as the analytical results.
When either electric field integral equation or magnetic field integral equation is employed to analyze electromagnetic scattering of conducting bodies, at some discrete resonance frequencies, the solution of Method Of Moments(MOM) matrix will be nonunique or unstable. In this paper, a new effective method is presented to solve this problem. At the interior resonance frequencies, Inagaki mode method, based on electric field integral equation, is used to filter out resonance modes and obtain right parameters. The proposed method possesses the merits of clarity in concept and simplicity in computation. A good agreement is achieved between the calculated results and the published as well as the analytical results.
2006, 28(9): 1740-1743.
Abstract:
The analytical solution of electromagnetic scattering to an anisotropic ferrite-coated conducting sphere by a plane wave is discussed in this paper. It is well known that the electromagnetic fields in three-dimensional ferrite medium and free space can be expressed into spherical vector wave functions of the first, second, third and fourth in ferrite anisotropic medium and isotropic medium. Applying the continue boundary condition of tangential component of electromagnetic fields in the interface between the ferrite anisotropic medium and free space, and the tangential electric field vanishing in the interface of the conducting sphere, the expansion coefficients of electromagnetic fields with spherical vector wave function in ferrite medium and the scattering fields in free space can be derived. The theoretic analysis and numerical result show that when the radius of conducting sphere approaches zero, the present method can be reduced to that of the homogeneous ferrite anisotropic medium. The present method can be applied to the analyses of related microwave devices, antennas and the character of radar targets.
The analytical solution of electromagnetic scattering to an anisotropic ferrite-coated conducting sphere by a plane wave is discussed in this paper. It is well known that the electromagnetic fields in three-dimensional ferrite medium and free space can be expressed into spherical vector wave functions of the first, second, third and fourth in ferrite anisotropic medium and isotropic medium. Applying the continue boundary condition of tangential component of electromagnetic fields in the interface between the ferrite anisotropic medium and free space, and the tangential electric field vanishing in the interface of the conducting sphere, the expansion coefficients of electromagnetic fields with spherical vector wave function in ferrite medium and the scattering fields in free space can be derived. The theoretic analysis and numerical result show that when the radius of conducting sphere approaches zero, the present method can be reduced to that of the homogeneous ferrite anisotropic medium. The present method can be applied to the analyses of related microwave devices, antennas and the character of radar targets.
2006, 28(9): 1744-1747.
Abstract:
Based on evaluation model, approach to estimating ATP(Area Timing and Power) of RA(Reconfigurable Architecture) at algorithm level is studied. According to ATP, RA design space exploration is carried out in two stages. First,the lowest cost for each architecture to implement all algorithms is searched; second, the optimized architecture is explored in RA design space. This method is independent on any architecture. It can value RA roundly, and fast produce a global optimal result. Application example has shown that it is effectively to guide RA design at an early stage.
Based on evaluation model, approach to estimating ATP(Area Timing and Power) of RA(Reconfigurable Architecture) at algorithm level is studied. According to ATP, RA design space exploration is carried out in two stages. First,the lowest cost for each architecture to implement all algorithms is searched; second, the optimized architecture is explored in RA design space. This method is independent on any architecture. It can value RA roundly, and fast produce a global optimal result. Application example has shown that it is effectively to guide RA design at an early stage.
2006, 28(9): 1748-1751.
Abstract:
A systematic method of fault diagnosis for analogue circuits based on the combination of Neural network with Wavelet Transform (WNT) is presented in the paper. Using the wavelet decomposition as a de-noise tool，the feature information is extracted by wavelet de-noise and its multi-resolution. The best fault classifier is obtained by comparing the performance of functional and weighted WNT. Diagnosis principles and steps are described. Finally, the reliability of the methods presented is shown by practical examples.
A systematic method of fault diagnosis for analogue circuits based on the combination of Neural network with Wavelet Transform (WNT) is presented in the paper. Using the wavelet decomposition as a de-noise tool，the feature information is extracted by wavelet de-noise and its multi-resolution. The best fault classifier is obtained by comparing the performance of functional and weighted WNT. Diagnosis principles and steps are described. Finally, the reliability of the methods presented is shown by practical examples.
2006, 28(9): 1758-1760.
Abstract:
A semi-infinite thermal model is presented which describes temperature rise in photoelectric detector under pulsed laser irradiation. The laser disturbance and damage thresholds with the detectors temperature rise are analyzed. The results show the disturbance and damage of detector are independent of the CO2 laser pulse-width, only depend directly on the energy density, at the same time, the disturbance threshold is one order lower than damage threshold. A numeric analysis about pulse CO2 laser irradiating satellite-borne HgCdTe detector is given. The feasibility of high average repetitive pulse laser disturbance and damage satellite-borne detector is qualitatively analyzed.
A semi-infinite thermal model is presented which describes temperature rise in photoelectric detector under pulsed laser irradiation. The laser disturbance and damage thresholds with the detectors temperature rise are analyzed. The results show the disturbance and damage of detector are independent of the CO2 laser pulse-width, only depend directly on the energy density, at the same time, the disturbance threshold is one order lower than damage threshold. A numeric analysis about pulse CO2 laser irradiating satellite-borne HgCdTe detector is given. The feasibility of high average repetitive pulse laser disturbance and damage satellite-borne detector is qualitatively analyzed.
2006, 28(9): 1752-1757.
Abstract:
Wireless Sensor Network (WSN), which is a novel class of computing and a new spot of information technology, is envisaged in application such as hostile environment surveillance and void event tracking. One fundamental issue in WSN is the deployment issue, which affects the performance and lifetime of the network. The deployment issue in WSN includes coverage, connectivity and energy-efficiency. The coverage problem in WSN is discussed in this paper. Therefore, the future work is presented.
Wireless Sensor Network (WSN), which is a novel class of computing and a new spot of information technology, is envisaged in application such as hostile environment surveillance and void event tracking. One fundamental issue in WSN is the deployment issue, which affects the performance and lifetime of the network. The deployment issue in WSN includes coverage, connectivity and energy-efficiency. The coverage problem in WSN is discussed in this paper. Therefore, the future work is presented.
