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2011 Vol. 33, No. 12
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2011, 33(12): 2795-2800.
doi: 10.3724/SP.J.1146.2011.00601
Abstract:
An efficient image fusion algorithm for polarization images based on Directionlets transform is proposed. Firstly, the several of polarization images are decomposed using Directionlets transform, which have multi-scale, multi-direction characteristics. Then, for the low-pass coefficients, the weighted averaging fusion rule is used. To select the better coefficients for the directional high-frequency ones, edge detection using two dimensional Teager energy and region directional contrast algorithm are used for fusion according to edge distribution differences in high frequency sub-band images. Experimental results show that compared with traditional algorithm, the proposed algorithm can get better visual effect and the significant information of original image like textures and contour details is well maintained.
An efficient image fusion algorithm for polarization images based on Directionlets transform is proposed. Firstly, the several of polarization images are decomposed using Directionlets transform, which have multi-scale, multi-direction characteristics. Then, for the low-pass coefficients, the weighted averaging fusion rule is used. To select the better coefficients for the directional high-frequency ones, edge detection using two dimensional Teager energy and region directional contrast algorithm are used for fusion according to edge distribution differences in high frequency sub-band images. Experimental results show that compared with traditional algorithm, the proposed algorithm can get better visual effect and the significant information of original image like textures and contour details is well maintained.
2011, 33(12): 2801-2806.
doi: 10.3724/SP.J.1146.2011.00380
Abstract:
This paper presents a suppression method based on Blind Signal Separation (BSS) to counter deception jamming in the single channel. First, the received signal is cut into 3 sections. Next, the mixed one is separated into two parts by the Joint Approximate Diagonalization of Eigenmatrices (JADE) BSS technology. Then, those 4 parts are combined with each other to form two complete signals, namely, echo and deception jamming. Finally, the target and deception jamming are identified by the character of phase quantization. The experiments validate the effectiveness of the proposed algorithm. This approach has good performance under high SNR. When SNR15 dB, the similarity coefficient of target echo is larger than 85%. Under the condition of 4 quantization bits, the probability of identification is almost close to 1 and the measurement error of target delay is below 0.3 s.
This paper presents a suppression method based on Blind Signal Separation (BSS) to counter deception jamming in the single channel. First, the received signal is cut into 3 sections. Next, the mixed one is separated into two parts by the Joint Approximate Diagonalization of Eigenmatrices (JADE) BSS technology. Then, those 4 parts are combined with each other to form two complete signals, namely, echo and deception jamming. Finally, the target and deception jamming are identified by the character of phase quantization. The experiments validate the effectiveness of the proposed algorithm. This approach has good performance under high SNR. When SNR15 dB, the similarity coefficient of target echo is larger than 85%. Under the condition of 4 quantization bits, the probability of identification is almost close to 1 and the measurement error of target delay is below 0.3 s.
2011, 33(12): 2807-2812.
doi: 10.3724/SP.J.1146.2010.00187
Abstract:
Due to suppression the influence of impulsive noise spikes (outliers) from desired signal direction of arrival in Global Positioning System (GPS) signals, the Householder-based multistage minimal module cascaded canceller is proposed. The method substitutes the weights of the Householder-based multistage Winner filter for the minimal module weights, which have the minimal module of the samples quotient, and adoptes in space-time anti-jamming processing in GPS receiver. The method has the prominent ability of restricting the influence of the impulsive noise spikes (outliers) from desired signal direction of arrival to adaptive weights, and the ability of low complexity, also fast convergence. Computational simulation results indicate the method achieves better fast convergence ability and a good performance in reducing the influence of the impulsive noise spikes (outliers) to adaptive weights.
Due to suppression the influence of impulsive noise spikes (outliers) from desired signal direction of arrival in Global Positioning System (GPS) signals, the Householder-based multistage minimal module cascaded canceller is proposed. The method substitutes the weights of the Householder-based multistage Winner filter for the minimal module weights, which have the minimal module of the samples quotient, and adoptes in space-time anti-jamming processing in GPS receiver. The method has the prominent ability of restricting the influence of the impulsive noise spikes (outliers) from desired signal direction of arrival to adaptive weights, and the ability of low complexity, also fast convergence. Computational simulation results indicate the method achieves better fast convergence ability and a good performance in reducing the influence of the impulsive noise spikes (outliers) to adaptive weights.
2011, 33(12): 2813-2818.
doi: 10.3724/SP.J.1146.2011.00361
Abstract:
Synthetic bandwidth technique provides an effective way to achieve the ultra high range resolution of airborne SAR. But in the real synthetic bandwidth system, the correlation is badly distorted by the phase error. If it is directly synthesized, the result will be seriously deteriorated. In this paper, based on the detailed research of the phase error, an improved Polynomial-Phase Transform (PPT) method is proposed to estimate the phase error from the echo directly. The Fourier Transform (FT) is replaced by the FRactional Fourier Transform (FRFT) in the new method, which can decrease the number of PT to reduce the SNR loss, and the circle amount is half. Theoretical analysis and the raw data prove the proposed approach is effective. Finally, the range resolution down to 0.05 m is obtained.
Synthetic bandwidth technique provides an effective way to achieve the ultra high range resolution of airborne SAR. But in the real synthetic bandwidth system, the correlation is badly distorted by the phase error. If it is directly synthesized, the result will be seriously deteriorated. In this paper, based on the detailed research of the phase error, an improved Polynomial-Phase Transform (PPT) method is proposed to estimate the phase error from the echo directly. The Fourier Transform (FT) is replaced by the FRactional Fourier Transform (FRFT) in the new method, which can decrease the number of PT to reduce the SNR loss, and the circle amount is half. Theoretical analysis and the raw data prove the proposed approach is effective. Finally, the range resolution down to 0.05 m is obtained.
2011, 33(12): 2819-2824.
doi: 10.3724/SP.J.1146.2011.00431
Abstract:
Joint calibration is a method to calibrate interferometric parameters of several adjacent scenes simultaneously, which needs less Ground Control Points (GCPs) and can realize the elevation continuity among the adjacent scenes. As the biases of the parameters can be acquired by solving the equations of GCPs and Corresponding Points (CPs), this paper presents one such joint calibration method by solving the equations using weighted optimization method. And the weightings depend on the correlation coefficient and location of the GCPs and CPs. This method can improve the Digital Elevation Model (DEM) accuracy, and this paper illustrates its successful application to interferometric SAR data.
Joint calibration is a method to calibrate interferometric parameters of several adjacent scenes simultaneously, which needs less Ground Control Points (GCPs) and can realize the elevation continuity among the adjacent scenes. As the biases of the parameters can be acquired by solving the equations of GCPs and Corresponding Points (CPs), this paper presents one such joint calibration method by solving the equations using weighted optimization method. And the weightings depend on the correlation coefficient and location of the GCPs and CPs. This method can improve the Digital Elevation Model (DEM) accuracy, and this paper illustrates its successful application to interferometric SAR data.
2011, 33(12): 2825-2830.
doi: 10.3724/SP.J.1146.2011.00375
Abstract:
In order to improve the Ambiguity-to-Signal Ratio (ASR) of spaceborne SAR, an adaptive Genetic Algorithm (GA) is proposed in this paper. By using the algorithm, ASR and antenna pattern are optimized simultaneously. Firstly，the ambiguity areas are determined, then the beamwidth and the side lobe level (including the side lobe level in the ambiguity areas of spaceborne SAR) of the antenna pattern are regarded as the objective function to synthesis the antenna pattern by using the adaptive GA. In order to avoid premature convergence, the crossover rate, the mutation rate and the mutation range are simultaneously adaptive during the optimization process. Compared to non-adaptive GA, the adaptive GA requires less iteration to converge and converges faster. The simulation results show that the ambiguity is depressed well via this method, which is quite useful to spaceborne SAR system designing.
In order to improve the Ambiguity-to-Signal Ratio (ASR) of spaceborne SAR, an adaptive Genetic Algorithm (GA) is proposed in this paper. By using the algorithm, ASR and antenna pattern are optimized simultaneously. Firstly，the ambiguity areas are determined, then the beamwidth and the side lobe level (including the side lobe level in the ambiguity areas of spaceborne SAR) of the antenna pattern are regarded as the objective function to synthesis the antenna pattern by using the adaptive GA. In order to avoid premature convergence, the crossover rate, the mutation rate and the mutation range are simultaneously adaptive during the optimization process. Compared to non-adaptive GA, the adaptive GA requires less iteration to converge and converges faster. The simulation results show that the ambiguity is depressed well via this method, which is quite useful to spaceborne SAR system designing.
2011, 33(12): 2831-2836.
doi: 10.3724/SP.J.1146.2011.00345
Abstract:
Existing methods for suppressing transient interference suffer from high computation cost due to that most of them rely on clutter suppression. To solve this problem, a novel method based on Complex Empirical Mode Decomposition (CEMD) is proposed to suppress transient interference in Over-The-Horizon Radar (OTHR). After decomposed radar echoes by using CEMD it accomplishes the detection of transient interference, excision of transient interference, and data reconstruction at the same time. The proposed method does neither require to perform clutter suppression, nor to reconstruct data by using prediction algorithm of AutoRegressive (AR) model. Thus, this method is of low complexity and high feasibility. Processing of the real data from OTHR system shows that the algorithm can efficiently suppress transient interferences.
Existing methods for suppressing transient interference suffer from high computation cost due to that most of them rely on clutter suppression. To solve this problem, a novel method based on Complex Empirical Mode Decomposition (CEMD) is proposed to suppress transient interference in Over-The-Horizon Radar (OTHR). After decomposed radar echoes by using CEMD it accomplishes the detection of transient interference, excision of transient interference, and data reconstruction at the same time. The proposed method does neither require to perform clutter suppression, nor to reconstruct data by using prediction algorithm of AutoRegressive (AR) model. Thus, this method is of low complexity and high feasibility. Processing of the real data from OTHR system shows that the algorithm can efficiently suppress transient interferences.
2011, 33(12): 2837-2845.
doi: 10.3724/SP.J.1146.2011.00359
Abstract:
Automatically extracting the Homologue Points (HPs) is a key step to achieve the automatic mapping of InSAR. Subjecting to constraints of the interferometric phase, a quality-map-oriented approach is proposed to extract HPs from the view of detecting and matching features between adjacent SAR images. This method adopts Scale Invariant Feature Transfor (SIFT) and Speed-Up Robust Feature (SURF) to detect interest points, and then the combination of three steps matching technique with criteria of interferometric optimization attributes to automatic HPs detection. Experiments on the same strip and adjacent strips demonstrate the efficiency and feasibility of the technique in the presence of magnitude speckle including significant difference in the imaging geometry.
Automatically extracting the Homologue Points (HPs) is a key step to achieve the automatic mapping of InSAR. Subjecting to constraints of the interferometric phase, a quality-map-oriented approach is proposed to extract HPs from the view of detecting and matching features between adjacent SAR images. This method adopts Scale Invariant Feature Transfor (SIFT) and Speed-Up Robust Feature (SURF) to detect interest points, and then the combination of three steps matching technique with criteria of interferometric optimization attributes to automatic HPs detection. Experiments on the same strip and adjacent strips demonstrate the efficiency and feasibility of the technique in the presence of magnitude speckle including significant difference in the imaging geometry.
2011, 33(12): 2846-2851.
doi: 10.3724/SP.J.1146.2011.00360
Abstract:
A novel algorithm for feature extraction of the precession angle and real length of the ballistic target using multi-aspect observed High Range Resolution Profile (HRRP) sequences is proposed. Taking the cone-shaped ballistic target into consideration, this paper analyzes the HRRP length when the target is precessing and indicates that the sequence of HRRP lengths can be approximate to a sinusoid function. Then, the model of multi-aspect observation is introduced and a novel algorithm, which is based on the multi-aspect observed HRRP sequences, is proposed to estimate the precession angle and real target length jointly. Afterwards, the effect of the radars distribution on the estimated errors is discussed. Finally, the simulation results are given for validating the proposed algorithms.
A novel algorithm for feature extraction of the precession angle and real length of the ballistic target using multi-aspect observed High Range Resolution Profile (HRRP) sequences is proposed. Taking the cone-shaped ballistic target into consideration, this paper analyzes the HRRP length when the target is precessing and indicates that the sequence of HRRP lengths can be approximate to a sinusoid function. Then, the model of multi-aspect observation is introduced and a novel algorithm, which is based on the multi-aspect observed HRRP sequences, is proposed to estimate the precession angle and real target length jointly. Afterwards, the effect of the radars distribution on the estimated errors is discussed. Finally, the simulation results are given for validating the proposed algorithms.
2011, 33(12): 2852-2857.
doi: 10.3724/SP.J.1146.2011.00442
Abstract:
The feature of the ground clutter in Wide Area Surveillance (WAS) mode of SAR/GMTI system is studied. Based on this feature, the clutter plus noise spectral density matrix of one Doppler cell can be estimated from another Doppler cells clutter plus noise spectral density matrix, and the corresponding transformation formula is also deduced. Then a new clutter plus noise spectral density matrix estimation method is proposed which estimates clutter plus noise spectral density matrix of the #em/em# th Doppler cell from both the #em/em#-1 th and the #em/em#+1th Doppler cell. The influences on the space-time processing performance from target contaminated samples can be greatly reduced when the new method combines with the eigenvector subspace projection method. The simulation results show the effectiveness of the proposed method.
The feature of the ground clutter in Wide Area Surveillance (WAS) mode of SAR/GMTI system is studied. Based on this feature, the clutter plus noise spectral density matrix of one Doppler cell can be estimated from another Doppler cells clutter plus noise spectral density matrix, and the corresponding transformation formula is also deduced. Then a new clutter plus noise spectral density matrix estimation method is proposed which estimates clutter plus noise spectral density matrix of the #em/em# th Doppler cell from both the #em/em#-1 th and the #em/em#+1th Doppler cell. The influences on the space-time processing performance from target contaminated samples can be greatly reduced when the new method combines with the eigenvector subspace projection method. The simulation results show the effectiveness of the proposed method.
2011, 33(12): 2858-2862.
doi: 10.3724/SP.J.1146.2010.01269
Abstract:
A method of joint estimation of angle and Doppler frequency for bistatic MIMO radar in spatial colored noise is presented. Utilizing the cross-correlation matrix which is formed by the adjacent outputs of match filters in the time domain, a new matrix is constructed to eliminate the influence of spatial colored noise, and the signal subspace is obtained from Singular Value Decomposition (SVD) of it. Then angles and Doppler frequencies can be estimated based on ESPRIT using the rotational factor produced by adjacent outputs of match filters. In this method, angles and Doppler frequencies can be obtained simultaneously and automatically paired without array aperture loss. Numerical results verify the effectiveness of the proposed method.
A method of joint estimation of angle and Doppler frequency for bistatic MIMO radar in spatial colored noise is presented. Utilizing the cross-correlation matrix which is formed by the adjacent outputs of match filters in the time domain, a new matrix is constructed to eliminate the influence of spatial colored noise, and the signal subspace is obtained from Singular Value Decomposition (SVD) of it. Then angles and Doppler frequencies can be estimated based on ESPRIT using the rotational factor produced by adjacent outputs of match filters. In this method, angles and Doppler frequencies can be obtained simultaneously and automatically paired without array aperture loss. Numerical results verify the effectiveness of the proposed method.
2011, 33(12): 2863-2868.
doi: 10.3724/SP.J.1146.2010.01377
Abstract:
The Compressive Sensing (CS) based SAR imaging method can reduce the sampling time, the data volume and save signal band width. However, the CS based methods are sensitive to noise and clutter. In this paper, a new imaging modality based on Bayesian Compressive Sensing (BCS) is proposed along with a novel compressed sampling scheme. This new imaging scheme requires minor change to traditional used system and allows both range and azimuth compressed sampling. Also, the Bayesian formalism accounts for additive noise encountered in the compressed measurement process. Experiments are carried out with noisy and cluttered imaging scenes to verify the new imaging scheme. The results indicate that the Bayesian formalism can provide a sharp and sparse image absence of side-lobes which is the common problem in conventional imaging methods and have fewer artifacts compared to the previous version of CS based methods.
The Compressive Sensing (CS) based SAR imaging method can reduce the sampling time, the data volume and save signal band width. However, the CS based methods are sensitive to noise and clutter. In this paper, a new imaging modality based on Bayesian Compressive Sensing (BCS) is proposed along with a novel compressed sampling scheme. This new imaging scheme requires minor change to traditional used system and allows both range and azimuth compressed sampling. Also, the Bayesian formalism accounts for additive noise encountered in the compressed measurement process. Experiments are carried out with noisy and cluttered imaging scenes to verify the new imaging scheme. The results indicate that the Bayesian formalism can provide a sharp and sparse image absence of side-lobes which is the common problem in conventional imaging methods and have fewer artifacts compared to the previous version of CS based methods.
2011, 33(12): 2869-2874.
doi: 10.3724/SP.J.1146.2011.00418
Abstract:
Radar High Range Resolution Profile (HRRP) plays an important role in target detection and recognition. For the properties of radar scattering response at high frequencies, a novel radar high-resolution imaging method using sparse signal representation is proposed in this paper. Based on ideal point-scattering model, an overcomplete basis is constructed, and an algorithm via smoothed l0 norm is also introduced to obtain radar HRRP. Experimental results indicate that good HRRP can be reconstructed even under the condition of data sampling rate decreasing or observation data missing, which shows that the proposed method is an effective radar imaging method.
Radar High Range Resolution Profile (HRRP) plays an important role in target detection and recognition. For the properties of radar scattering response at high frequencies, a novel radar high-resolution imaging method using sparse signal representation is proposed in this paper. Based on ideal point-scattering model, an overcomplete basis is constructed, and an algorithm via smoothed l0 norm is also introduced to obtain radar HRRP. Experimental results indicate that good HRRP can be reconstructed even under the condition of data sampling rate decreasing or observation data missing, which shows that the proposed method is an effective radar imaging method.
2011, 33(12): 2875-2880.
doi: 10.3724/SP.J.1146.2011.00440
Abstract:
A new algorithm to jointly estimate the DOD-DOA of bistatic MIMO radar is proposed based on transmit beamspace-parallel factor. For the problem of the power being transmitted dispersedly in traditional MIMO radar, the optimizing criterion for designing beam weight matrix is proposed combining the focus range of the transmit power with the desired transmitting steering vector. This constrained optimizing formula can be reformed to a standard Second Order Cone Programming (SOCP) fashion and be solved with interior-point method. Furthermore, the DODs and DOAs of target are estimated by using the PARAllel FACtor (PARAFAC) algorithm. The simulation results illustrate that: the beam weight matrix which can be designed off-line makes the transmitting power focus within the spatial sector of interesting targets. And the distribution of the transmitting power in that spatial sector is approximately uniform. Therefore, when the same angle estimation algorithm and the same transmit power are utilized, the transmit beamspace-based MIMO radar can perform better angular accuracy than the traditional MIMO radar.
A new algorithm to jointly estimate the DOD-DOA of bistatic MIMO radar is proposed based on transmit beamspace-parallel factor. For the problem of the power being transmitted dispersedly in traditional MIMO radar, the optimizing criterion for designing beam weight matrix is proposed combining the focus range of the transmit power with the desired transmitting steering vector. This constrained optimizing formula can be reformed to a standard Second Order Cone Programming (SOCP) fashion and be solved with interior-point method. Furthermore, the DODs and DOAs of target are estimated by using the PARAllel FACtor (PARAFAC) algorithm. The simulation results illustrate that: the beam weight matrix which can be designed off-line makes the transmitting power focus within the spatial sector of interesting targets. And the distribution of the transmitting power in that spatial sector is approximately uniform. Therefore, when the same angle estimation algorithm and the same transmit power are utilized, the transmit beamspace-based MIMO radar can perform better angular accuracy than the traditional MIMO radar.
2011, 33(12): 2881-2887.
doi: 10.3724/SP.J.1146.2011.00331
Abstract:
Single-image zooming is an ill-posed problem. Using the self-similarity feature among local structure in an image which can be maintained in the scale space and the advantage of NonSubsampled Contourlet Transform (NSCT), a single image super-resolution reconstruction algorithm based on image analogies in NSCT domain is proposed. Firstly, NSCT is performed on the original image and the degraded image at different scales and directions, thus low-pass subband pair and varieties of directional bandpass subband pairs are obtained. Then the high resolution low-pass subband and varieties of directional bandpass subband are generated by using image self-analogies. Finally, the super-resolution reconstructed image is obtained by transforming these subband coefficients back to the spatial domain. The experimental results show that the algorithm can be executed independently without any supposed outliers and it can compute much more sharply than general image analogies methods. It also can generate more reasonable details than general image analogies methods, thus the edges are much clearer and the image is more natural-looking.
Single-image zooming is an ill-posed problem. Using the self-similarity feature among local structure in an image which can be maintained in the scale space and the advantage of NonSubsampled Contourlet Transform (NSCT), a single image super-resolution reconstruction algorithm based on image analogies in NSCT domain is proposed. Firstly, NSCT is performed on the original image and the degraded image at different scales and directions, thus low-pass subband pair and varieties of directional bandpass subband pairs are obtained. Then the high resolution low-pass subband and varieties of directional bandpass subband are generated by using image self-analogies. Finally, the super-resolution reconstructed image is obtained by transforming these subband coefficients back to the spatial domain. The experimental results show that the algorithm can be executed independently without any supposed outliers and it can compute much more sharply than general image analogies methods. It also can generate more reasonable details than general image analogies methods, thus the edges are much clearer and the image is more natural-looking.
2011, 33(12): 2888-2893.
doi: 10.3724/SP.J.1146.2010.01371
Abstract:
In order to solve the problem of beamformers performance degradation caused by signal steering vector and sample covariance matrix mismatch errors, a robust adaptive beamforming algorithm based on Super-Gaussian Loading (SGL) is put forward in this paper. By correcting these two error uncertainties together through lp norm, the proposed algorithm overcomes the drawback inl2 norm issue that cannot optimally calibrate the two errors at the same time. The optimalis obtained through genetic algorithm, and the better output performance can be got comparing withlp norm approach in different experiment conditions. The Super-Gaussian Loading algorithm transforms the complex modeling for two uncertainties into norm p optimization problem, and thus gets better result than standard diagonal loading method.
In order to solve the problem of beamformers performance degradation caused by signal steering vector and sample covariance matrix mismatch errors, a robust adaptive beamforming algorithm based on Super-Gaussian Loading (SGL) is put forward in this paper. By correcting these two error uncertainties together through lp norm, the proposed algorithm overcomes the drawback inl2 norm issue that cannot optimally calibrate the two errors at the same time. The optimalis obtained through genetic algorithm, and the better output performance can be got comparing withlp norm approach in different experiment conditions. The Super-Gaussian Loading algorithm transforms the complex modeling for two uncertainties into norm p optimization problem, and thus gets better result than standard diagonal loading method.
2011, 33(12): 2894-2901.
doi: 10.3724/SP.J.1146.2011.00233
Abstract:
An object detection algorithm based on shape feature of combined regions is presented. Object candidates are first extracted by combining segmented regions, and then their feature vectors which contain angle chain and ratio of arc-chord distance to chord length are obtained. The parallel support vector machines are trained. The proposed algorithm requires low segmentation quality and can detect objects in blurred or low contrast images. The experiment on ETHZ Shape Classes demonstrates the effectiveness of the proposed algorithm.
An object detection algorithm based on shape feature of combined regions is presented. Object candidates are first extracted by combining segmented regions, and then their feature vectors which contain angle chain and ratio of arc-chord distance to chord length are obtained. The parallel support vector machines are trained. The proposed algorithm requires low segmentation quality and can detect objects in blurred or low contrast images. The experiment on ETHZ Shape Classes demonstrates the effectiveness of the proposed algorithm.
2011, 33(12): 2902-2908.
doi: 10.3724/SP.J.1146.2011.00304
Abstract:
Information transferring process in sensor network will appear delay, out-of-sequence even dropout. How to make full use of such information is extremely important to improve state estimation accuracy. In order to further overcome the problems in the existing methods, a novel delay measurement filter based on the pseudo-measurement model library is proposed in this paper. Firstly, a pseudo-measurement model library under finite delay case is built for the linear time invariant system with the invariant parameters property. Secondly, according to current time arrival delay or real time measurement, the corresponding model is selected in the model library. Thirdly, a new hybrid filter with predict-estimator, filter-estimator and fusion-estimator is proposed for the system described by the selected measurement model and the state model. The simulations illustrate the effectiveness and optimality of the proposed method.
Information transferring process in sensor network will appear delay, out-of-sequence even dropout. How to make full use of such information is extremely important to improve state estimation accuracy. In order to further overcome the problems in the existing methods, a novel delay measurement filter based on the pseudo-measurement model library is proposed in this paper. Firstly, a pseudo-measurement model library under finite delay case is built for the linear time invariant system with the invariant parameters property. Secondly, according to current time arrival delay or real time measurement, the corresponding model is selected in the model library. Thirdly, a new hybrid filter with predict-estimator, filter-estimator and fusion-estimator is proposed for the system described by the selected measurement model and the state model. The simulations illustrate the effectiveness and optimality of the proposed method.
2011, 33(12): 2909-2915.
doi: 10.3724/SP.J.1146.2011.00455
Abstract:
In order to avoid the condition that most of the segmentation based recognition methods have relied too much on the quality of image segments, a new object recognition method is proposed based on Multi-Level- probabilistic Latent Semantic Analysis (ML-pLSA) object recognition algorithm. Firstly, multiple segmentations at different levels are computed for each image, and then object classes on each segment region are estimated by using pLSA and Bag-Of-Words (BOW). The final results are obtained by fusing estimation results at multiple levels. The proposed algorithm is evaluated on Graz-02 dataset, a challenging dataset that contains large changes in object scale, object viewpoint and illumination condition. The experiment results demonstrate that the proposed method performs better than traditional object recognition methods in both accuracy and robustness.
In order to avoid the condition that most of the segmentation based recognition methods have relied too much on the quality of image segments, a new object recognition method is proposed based on Multi-Level- probabilistic Latent Semantic Analysis (ML-pLSA) object recognition algorithm. Firstly, multiple segmentations at different levels are computed for each image, and then object classes on each segment region are estimated by using pLSA and Bag-Of-Words (BOW). The final results are obtained by fusing estimation results at multiple levels. The proposed algorithm is evaluated on Graz-02 dataset, a challenging dataset that contains large changes in object scale, object viewpoint and illumination condition. The experiment results demonstrate that the proposed method performs better than traditional object recognition methods in both accuracy and robustness.
2011, 33(12): 2916-2921.
doi: 10.3724/SP.J.1146.2011.00406
Abstract:
To improve the performance of proxy re-signature schemes, the schemes of on-line/off-line proxy re-signature are proposed in this paper. The main idea is to split the re-signing procedure into two phases: the off-line and on-line phases. Most of the computations are performed in the off-line phase before seeing the message to be re-signed. The results of this precomputation are saved and then used in the on-line phase when the message must be re-signed. On-line/off-line proxy re-signature schemes are used in a particular scenario where the proxy must respond quickly once the message to be re-signed is presented. Based on the formal definition of on-line/off-line proxy re-signatures, an efficient construction of on-line/off-line proxy re-signature is presented. It can convert any proxy re-signature scheme into a highly efficient on-line/off-line one. Security is proved in the random oracle model. Compared wirh the existing proxy re-signature schemes, the new scheme is more efficient in the communication cost and the computational cost. It needs one modular subtraction computation and one modular multiplication computation in the on-line re-signing generation algorithm.
To improve the performance of proxy re-signature schemes, the schemes of on-line/off-line proxy re-signature are proposed in this paper. The main idea is to split the re-signing procedure into two phases: the off-line and on-line phases. Most of the computations are performed in the off-line phase before seeing the message to be re-signed. The results of this precomputation are saved and then used in the on-line phase when the message must be re-signed. On-line/off-line proxy re-signature schemes are used in a particular scenario where the proxy must respond quickly once the message to be re-signed is presented. Based on the formal definition of on-line/off-line proxy re-signatures, an efficient construction of on-line/off-line proxy re-signature is presented. It can convert any proxy re-signature scheme into a highly efficient on-line/off-line one. Security is proved in the random oracle model. Compared wirh the existing proxy re-signature schemes, the new scheme is more efficient in the communication cost and the computational cost. It needs one modular subtraction computation and one modular multiplication computation in the on-line re-signing generation algorithm.
2011, 33(12): 2922-2928.
doi: 10.3724/SP.J.1146.2011.00399
Abstract:
In an Identity-Based Encryption (IBE) scheme, an users public key can be derived from his identity directly, which eliminates the cost of the certificate management in Public Key Infrastructure (PKI) systems. However, the IBE has the key escrow issue, that is, the trusted Private Key Generator (PKG), can decrypt the users ciphertexts and leak their secret keys. To solve this issue, most existing schemes either can only solve part of the key escrow problem, or need a secure key distribution channel and complicated identification schemes causing great performance cost. This paper proposes a Secure and Accountable Identity-Based Encryption (SA-IBE) scheme, in which users initial secret key is issued by the PKG, and then its privacy is consolidated parallel by multiple Key Privacy Authorities (KPAs), so that no single authority can get the users secret key or message. In addition, an efficient and accountable single PKG identification scheme is designed, and the blinding technique is used to remove the secure channel for the key distribution. Based on the standard Diffie-Hellman assumption, it is proved that SA-IBE can efficiently address the key escrow issue while ensures its security and the accountability of the system identification.
In an Identity-Based Encryption (IBE) scheme, an users public key can be derived from his identity directly, which eliminates the cost of the certificate management in Public Key Infrastructure (PKI) systems. However, the IBE has the key escrow issue, that is, the trusted Private Key Generator (PKG), can decrypt the users ciphertexts and leak their secret keys. To solve this issue, most existing schemes either can only solve part of the key escrow problem, or need a secure key distribution channel and complicated identification schemes causing great performance cost. This paper proposes a Secure and Accountable Identity-Based Encryption (SA-IBE) scheme, in which users initial secret key is issued by the PKG, and then its privacy is consolidated parallel by multiple Key Privacy Authorities (KPAs), so that no single authority can get the users secret key or message. In addition, an efficient and accountable single PKG identification scheme is designed, and the blinding technique is used to remove the secure channel for the key distribution. Based on the standard Diffie-Hellman assumption, it is proved that SA-IBE can efficiently address the key escrow issue while ensures its security and the accountability of the system identification.
2011, 33(12): 2929-2934.
doi: 10.3724/SP.J.1146.2011.00372
Abstract:
According to the fact that security against Selective-Opening Attack (SOA) is confined to the case of Public-Key Encryption (PKE) but is difficult to yield solutions in Identity Based Encryption (IBE) in resent years, a novel identity-based broadcast encryption scheme against selective opening attack is proposed by combining with Waters et al.linear or random techniques and the broadcast encryption model. Based on the standard model without tags, the scheme can achieve constant-size keys and ciphertexts. Furthermore, the schemes security is reduced to the decisional linear assumption. The analysis results indicate that the scheme of this paper is selective opening attack secure and can satisfy the higher efficiency and practice requirement.
According to the fact that security against Selective-Opening Attack (SOA) is confined to the case of Public-Key Encryption (PKE) but is difficult to yield solutions in Identity Based Encryption (IBE) in resent years, a novel identity-based broadcast encryption scheme against selective opening attack is proposed by combining with Waters et al.linear or random techniques and the broadcast encryption model. Based on the standard model without tags, the scheme can achieve constant-size keys and ciphertexts. Furthermore, the schemes security is reduced to the decisional linear assumption. The analysis results indicate that the scheme of this paper is selective opening attack secure and can satisfy the higher efficiency and practice requirement.
2011, 33(12): 2935-2941.
doi: 10.3724/SP.J.1146.2011.00483
Abstract:
Full diversity Low Density Parity Check (LDPC) codes construction is the hot spot in LDPC field at present. Traditional construction algorithm designs column full rank check submatrix to realize full diversity LDPC codes under ML decoding algorithm. However, under BP decoding algorithm, the LDPC codes designed based on ML principle can not guarantee full diversity. In this paper, the construction method of full diversity LDPC codes under BP decoding algorithm is first put forward by changing the structure of parity check matrix, then, density propagetion process of full diversity LDPC codes is analyzed. Finally, the relationship between the structure of full diversity LDPC codes and the coding gain is researched, and the algorithm to improve coding gain is given. Simulation results show that the proposed algthriom can not only achieve full diversity, but also get better performace than random constructed LDPC codes.
Full diversity Low Density Parity Check (LDPC) codes construction is the hot spot in LDPC field at present. Traditional construction algorithm designs column full rank check submatrix to realize full diversity LDPC codes under ML decoding algorithm. However, under BP decoding algorithm, the LDPC codes designed based on ML principle can not guarantee full diversity. In this paper, the construction method of full diversity LDPC codes under BP decoding algorithm is first put forward by changing the structure of parity check matrix, then, density propagetion process of full diversity LDPC codes is analyzed. Finally, the relationship between the structure of full diversity LDPC codes and the coding gain is researched, and the algorithm to improve coding gain is given. Simulation results show that the proposed algthriom can not only achieve full diversity, but also get better performace than random constructed LDPC codes.
2011, 33(12): 2942-2947.
doi: 10.3724/SP.J.1146.2010.01338
Abstract:
This paper presents a high-throughput encoding method for IEEE 802.16e-like Low-Density Parity- Check (LDPC) codes. It is based on a fast double-recursion pipeline method, and can significantly improve the encoding speed. For more parallelism and less storage consumption, a partially-parallel architecture is designed. Furthermore, the storage system is optimized for parallel multi-frame coding, and the data storage unit and RAM address generator are shared for improving resource utilization. Design results are provided for an implementation on a Xilinx XC4VLX40 FPGA for codes with code length 2304 bit. It is shown that the proposed method can achieve a throughput in excess of 10 Gbps under a maximum clock frequency of 200 MHz, with the requirement of no more than 15% gate area and about 50% RAM storage.
This paper presents a high-throughput encoding method for IEEE 802.16e-like Low-Density Parity- Check (LDPC) codes. It is based on a fast double-recursion pipeline method, and can significantly improve the encoding speed. For more parallelism and less storage consumption, a partially-parallel architecture is designed. Furthermore, the storage system is optimized for parallel multi-frame coding, and the data storage unit and RAM address generator are shared for improving resource utilization. Design results are provided for an implementation on a Xilinx XC4VLX40 FPGA for codes with code length 2304 bit. It is shown that the proposed method can achieve a throughput in excess of 10 Gbps under a maximum clock frequency of 200 MHz, with the requirement of no more than 15% gate area and about 50% RAM storage.
2011, 33(12): 2948-2953.
doi: 10.3724/SP.J.1146.2011.00437
Abstract:
Satellite mobile channel can be described as a fading channel model based on Markov process. Firstly, the predictability of satellite mobile channel is analyzed in this paper. Then a long term prediction method is proposed based on weighting prediction. The method resamples the channel sample values with a sample rate 2 times of the Markov state transferring speed, and uses the correlation of the channel states and Markov state transfer probability to predict the future channel state and outputs the channel prediction value of the long term future according to autoregression prediction model. Simulation results show that by using the proposed method the mean square error can reach about 10-2 when signal noise ratio is relatively high, moreover, the system average bit error rate can be reduced and the system throughput can be increased. This method can be used to instruct the adaptive transmission and adaptive resource assignment of satellite mobile communications.
Satellite mobile channel can be described as a fading channel model based on Markov process. Firstly, the predictability of satellite mobile channel is analyzed in this paper. Then a long term prediction method is proposed based on weighting prediction. The method resamples the channel sample values with a sample rate 2 times of the Markov state transferring speed, and uses the correlation of the channel states and Markov state transfer probability to predict the future channel state and outputs the channel prediction value of the long term future according to autoregression prediction model. Simulation results show that by using the proposed method the mean square error can reach about 10-2 when signal noise ratio is relatively high, moreover, the system average bit error rate can be reduced and the system throughput can be increased. This method can be used to instruct the adaptive transmission and adaptive resource assignment of satellite mobile communications.
2011, 33(12): 2954-2959.
doi: 10.3724/SP.J.1146.2011.00347
Abstract:
A resource scheduling cross-layer design scheme in FDD-OFDMA mobile communication downlink system about the issue of limited interference is proposed. A mathematical formulation of optimization issue is provided with the objective of maximizing system goodput under target Packet Error Rate (PER) constraint. The proposed method can use ACK/NAK feedback information to implement user selection and rate allocation without Channel State Information (CSI) at the base station. Simulation results demonstrate that the system goodput of proposed algorithms is close to the condition of with channel state information at the base station, it also has low complexity.
A resource scheduling cross-layer design scheme in FDD-OFDMA mobile communication downlink system about the issue of limited interference is proposed. A mathematical formulation of optimization issue is provided with the objective of maximizing system goodput under target Packet Error Rate (PER) constraint. The proposed method can use ACK/NAK feedback information to implement user selection and rate allocation without Channel State Information (CSI) at the base station. Simulation results demonstrate that the system goodput of proposed algorithms is close to the condition of with channel state information at the base station, it also has low complexity.
2011, 33(12): 2960-2964.
doi: 10.3724/SP.J.1146.2011.00401
Abstract:
An inter-relay interference suppression method is proposed at the relay based on the Autocorrelation Matching (AM) theory in the two-path relay cooperative system. The new approach takes three steps at the relay. Firstly, the new method is used to remove the inter-relay interference. Unlike the Partial Interference Cancellation (PIC) and Full Interference Cancellation (FIC) scheme, it is insensitive to the time synchronization between the two relays. Secondly, the signal will pass through a FIR pre-filter to satisfy the autocorrelation diversity condition. The pre-filters of the two relays are identical. Finally, the signal will be Amplified and Forwarded (AF) to the destination. At the destination, the received signal will firstly pass through a reversal filter caused by the relay nodes, then, it will be equalized, demodulated and decoded like the conventional systems. Compared to the PIC and FIC methods, the proposed approach alleviates the burden on the destination and its performance is not so dependent on the assumption that the destination knows the perfect channel state information for every link, moreover, it has good performance and is also robust.
An inter-relay interference suppression method is proposed at the relay based on the Autocorrelation Matching (AM) theory in the two-path relay cooperative system. The new approach takes three steps at the relay. Firstly, the new method is used to remove the inter-relay interference. Unlike the Partial Interference Cancellation (PIC) and Full Interference Cancellation (FIC) scheme, it is insensitive to the time synchronization between the two relays. Secondly, the signal will pass through a FIR pre-filter to satisfy the autocorrelation diversity condition. The pre-filters of the two relays are identical. Finally, the signal will be Amplified and Forwarded (AF) to the destination. At the destination, the received signal will firstly pass through a reversal filter caused by the relay nodes, then, it will be equalized, demodulated and decoded like the conventional systems. Compared to the PIC and FIC methods, the proposed approach alleviates the burden on the destination and its performance is not so dependent on the assumption that the destination knows the perfect channel state information for every link, moreover, it has good performance and is also robust.
2011, 33(12): 2965-2970.
doi: 10.3724/SP.J.1146.2011.00387
Abstract:
A network selection algorithm for CDMA/OFDMA heterogeneous networks using periodic load measurement scheme, which is named as Minimizing SIR Outage Probability (MSOP) network selection. In this algorithm, the best access probability is derived through the Wilkinson approximation method. Simulation results show that the MSOP algorithm can realize load balancing with long measurement interval, and consequently get better trunking gain, so as to improve the resource efficiency. Mean while, the average SIR outage probability is also decreased, so users can get better experience.
A network selection algorithm for CDMA/OFDMA heterogeneous networks using periodic load measurement scheme, which is named as Minimizing SIR Outage Probability (MSOP) network selection. In this algorithm, the best access probability is derived through the Wilkinson approximation method. Simulation results show that the MSOP algorithm can realize load balancing with long measurement interval, and consequently get better trunking gain, so as to improve the resource efficiency. Mean while, the average SIR outage probability is also decreased, so users can get better experience.
2011, 33(12): 2971-2977.
doi: 10.3724/SP.J.1146.2011.00310
Abstract:
In cooperative communication, the relay node is used to retransmit the data packets of the source. However, helping other nodes transmitting packets may decrease the performance of the relay, it is less efficient from the point of the relay, which is called the relay inefficient problem in cooperative communication. In order to resolve this problem, a cooperative MAC is proposed based on network coding for Ad hoc networks. The proposed protocol combines the network coding and cooperative communication and allows a relay to use the cooperative retransmission to deliver its own data packets as well. Such a special scheme resolves the relay inefficient problem by network coding and improves the system performance as well. Moreover, the proposed protocol is modeled by a modified Markov chain in the multihop networks, in which considers the cooperative communications and the network coding. Furthermore, the impacts of multihop and channel condition for the system performance are also discussed in this paper. The simulation results show the proposed protocol can significantly improve the system performance compared with the general cooperative MAC and the network coding is really efficiency to resolve the relay inefficient problem in cooperative communication.
In cooperative communication, the relay node is used to retransmit the data packets of the source. However, helping other nodes transmitting packets may decrease the performance of the relay, it is less efficient from the point of the relay, which is called the relay inefficient problem in cooperative communication. In order to resolve this problem, a cooperative MAC is proposed based on network coding for Ad hoc networks. The proposed protocol combines the network coding and cooperative communication and allows a relay to use the cooperative retransmission to deliver its own data packets as well. Such a special scheme resolves the relay inefficient problem by network coding and improves the system performance as well. Moreover, the proposed protocol is modeled by a modified Markov chain in the multihop networks, in which considers the cooperative communications and the network coding. Furthermore, the impacts of multihop and channel condition for the system performance are also discussed in this paper. The simulation results show the proposed protocol can significantly improve the system performance compared with the general cooperative MAC and the network coding is really efficiency to resolve the relay inefficient problem in cooperative communication.
2011, 33(12): 2978-2883.
doi: 10.3724/SP.J.1146.2011.00098
Abstract:
A three-node Amplify-and-Forward (AF) cooperative diversity network model is proposed in the paper. The randomness of feedback delay analysis is presented for the proposed model which the source transmits a frame over Nakagami-m fading channel. The frame can be transmitted from the direct link or relay link to the destination node. Additionally, Adaptive Modulation and Coding (AMC) technique is used in the source node of the analytical model which allows multi-rate transmission of the data frame, the transmitted mode is chosen according to the channel conditions. Based on the above reasons, the steady distribution of the feedback delay is analyzed, and a Finite State Markov Channel (FSMC) is developed to evaluate performance the Nakagami-m channel and obtain the channel state transition matrix. Then the transition probability of the feedback delay is derived. The simulative results are compared with the theoretic results, the results verify that the theoretic analysis is correct. Finally, the effect of channel fading coefficients and maximum frame error rate on the probability distribution of the feedback delay performance is analyzed.
A three-node Amplify-and-Forward (AF) cooperative diversity network model is proposed in the paper. The randomness of feedback delay analysis is presented for the proposed model which the source transmits a frame over Nakagami-m fading channel. The frame can be transmitted from the direct link or relay link to the destination node. Additionally, Adaptive Modulation and Coding (AMC) technique is used in the source node of the analytical model which allows multi-rate transmission of the data frame, the transmitted mode is chosen according to the channel conditions. Based on the above reasons, the steady distribution of the feedback delay is analyzed, and a Finite State Markov Channel (FSMC) is developed to evaluate performance the Nakagami-m channel and obtain the channel state transition matrix. Then the transition probability of the feedback delay is derived. The simulative results are compared with the theoretic results, the results verify that the theoretic analysis is correct. Finally, the effect of channel fading coefficients and maximum frame error rate on the probability distribution of the feedback delay performance is analyzed.
2011, 33(12): 2984-2989.
doi: 10.3724/SP.J.1146.2011.00119
Abstract:
Energy-saving routing is one of the important topics in Wireless Ad hoc NETworks (WANETs), which is significant for prolonging network lifetime. Under convention routing, the data delivery paths, with each used by a pair of nodes, may intersect at some nodes, which causes these shared nodes to forward packets from multiple intersecting paths, making them expend more energy than other nodes and become invalid quickly due to energy depletion. To overcome the problem of uneven energy consumption among nodes, a Network Coding Based Energy Efficient Routing (NCBEER) is presented in this paper, which is able to capture the opportunity of path intersecting, allows the shared nodes to encode the forwarded packets, and multicasts the coded packets to neighboring nodes so that the number of transmissions and energy expenditure are reduced. In addition, the average number of multicasts for a coding node to guarantee the coded packet to be received by all the receiving nodes is derived; and the delivery cost of a wireless link is defined, which is used by NCBEER to dispatch packets to different paths. Simulation shows that NCBEER is able to reduce and balance energy expenditure of nodes and network lifetime is prolonged.
Energy-saving routing is one of the important topics in Wireless Ad hoc NETworks (WANETs), which is significant for prolonging network lifetime. Under convention routing, the data delivery paths, with each used by a pair of nodes, may intersect at some nodes, which causes these shared nodes to forward packets from multiple intersecting paths, making them expend more energy than other nodes and become invalid quickly due to energy depletion. To overcome the problem of uneven energy consumption among nodes, a Network Coding Based Energy Efficient Routing (NCBEER) is presented in this paper, which is able to capture the opportunity of path intersecting, allows the shared nodes to encode the forwarded packets, and multicasts the coded packets to neighboring nodes so that the number of transmissions and energy expenditure are reduced. In addition, the average number of multicasts for a coding node to guarantee the coded packet to be received by all the receiving nodes is derived; and the delivery cost of a wireless link is defined, which is used by NCBEER to dispatch packets to different paths. Simulation shows that NCBEER is able to reduce and balance energy expenditure of nodes and network lifetime is prolonged.
2011, 33(12): 2990-2994.
doi: 10.3724/SP.J.1146.2011.00627
Abstract:
Two subspace distance calculation algorithms are proposed for codeword search of limited feedback precoding multi-user MIMO systems. The equivalence of subspace distance and chordal distance are first proved, then the complexity of chordal distance calculation and proposed two subspace distance calculation algorithms are analyzed. Simulation results verify that subspace distance calculation algorithms cost fewer operations. Further more the proper one of two proposed algorithms can be chosen based on different hardware implementations and transmitting antenna numbers.
Two subspace distance calculation algorithms are proposed for codeword search of limited feedback precoding multi-user MIMO systems. The equivalence of subspace distance and chordal distance are first proved, then the complexity of chordal distance calculation and proposed two subspace distance calculation algorithms are analyzed. Simulation results verify that subspace distance calculation algorithms cost fewer operations. Further more the proper one of two proposed algorithms can be chosen based on different hardware implementations and transmitting antenna numbers.
2011, 33(12): 2995-3001.
doi: 10.3724/SP.J.1146.2011.00634
Abstract:
Co-channel interference is serious when multiple Bluetooth piconets coexist in a limited area. Therefore, a co-channel interference suppression method based on the channels switching is proposed. With the method, channels may switch from one to another when a piconet carries out retransfer packets. In order to approach practical scenarios and considering that identical frequency channel in different piconets may not lead to co-channel interference, some issues are taken into account in the analysis process, such as the return packets, the frequency hopping guard time, and the coexistence of three packet sizes. Simulations are carried out on the network performance of piconets. The simulation consequence indicates that the methodology can reduce the PER, and the throughput of piconet is improved effectively. And particularly, when the range of piconet number is set from 14 to 57, the throughput can go up 260 kbps.
Co-channel interference is serious when multiple Bluetooth piconets coexist in a limited area. Therefore, a co-channel interference suppression method based on the channels switching is proposed. With the method, channels may switch from one to another when a piconet carries out retransfer packets. In order to approach practical scenarios and considering that identical frequency channel in different piconets may not lead to co-channel interference, some issues are taken into account in the analysis process, such as the return packets, the frequency hopping guard time, and the coexistence of three packet sizes. Simulations are carried out on the network performance of piconets. The simulation consequence indicates that the methodology can reduce the PER, and the throughput of piconet is improved effectively. And particularly, when the range of piconet number is set from 14 to 57, the throughput can go up 260 kbps.
2011, 33(12): 3002-3007.
doi: 10.3724/SP.J.1146.2011.00364
Abstract:
To solve the personalized information content and services recommended issues in mobile communication network, a collaborative filtering algorithm based on users social relationship mining in mobile communication network is proposed with the social network analysis method. It effectively mitigates data sparsely for preferred forecasting and recommendations by using the information of social networks obtained from predicting the potential relationship between social networks and the most similar set of users according to the degree of similar relationship between the users. The algorithm is proved more accurate and feasible in the experiments by using the public data sets and the simulated data sets.
To solve the personalized information content and services recommended issues in mobile communication network, a collaborative filtering algorithm based on users social relationship mining in mobile communication network is proposed with the social network analysis method. It effectively mitigates data sparsely for preferred forecasting and recommendations by using the information of social networks obtained from predicting the potential relationship between social networks and the most similar set of users according to the degree of similar relationship between the users. The algorithm is proved more accurate and feasible in the experiments by using the public data sets and the simulated data sets.
2011, 33(12): 3008-3014.
doi: 10.3724/SP.J.1146.2011.00297
Abstract:
To lessen the impact of multicast member with the worst link quality on multicast rate in single source multicast, static and dynamic alternative scheduling algorithms are presented for reliable multicast with two sources. Through transmitting encode packets alternately, the presented algorithms exploit the link heterogeneity between multicast members and different sources. Compared with single source multicast, theoretical analysis and simulations show that both scheduling algorithms can effictively improve the multicast rate, thereby decrease expected time for completing transmission. Dynamic alternative scheduling algorithm acheives less expected transmission time by dynamically updating parameter.
To lessen the impact of multicast member with the worst link quality on multicast rate in single source multicast, static and dynamic alternative scheduling algorithms are presented for reliable multicast with two sources. Through transmitting encode packets alternately, the presented algorithms exploit the link heterogeneity between multicast members and different sources. Compared with single source multicast, theoretical analysis and simulations show that both scheduling algorithms can effictively improve the multicast rate, thereby decrease expected time for completing transmission. Dynamic alternative scheduling algorithm acheives less expected transmission time by dynamically updating parameter.
2011, 33(12): 3015-3021.
doi: 10.3724/SP.J.1146.2011.00414
Abstract:
Considering the characteristics of attack decision-making issue in the domain of network attack and defense, the network attack graph model is extended from the view of attacker. Atomic attack is built by instantiating the attack pattern according the vulnerability. Maintaining the causality of precondition and effect condition of the atomic attack, therefore, the Extended Attack Graph (EAG) model is proposed. Furthermore, a network attack decision-making algorithm based on the extended attack graph is put forward; which can forecast attack effect dynamically and build the valid attack path and its occurrence probability through the in-depth analysis of the models features. Through the network attack and defense experiments, the results show the completeness and soundness of the algorithm.
Considering the characteristics of attack decision-making issue in the domain of network attack and defense, the network attack graph model is extended from the view of attacker. Atomic attack is built by instantiating the attack pattern according the vulnerability. Maintaining the causality of precondition and effect condition of the atomic attack, therefore, the Extended Attack Graph (EAG) model is proposed. Furthermore, a network attack decision-making algorithm based on the extended attack graph is put forward; which can forecast attack effect dynamically and build the valid attack path and its occurrence probability through the in-depth analysis of the models features. Through the network attack and defense experiments, the results show the completeness and soundness of the algorithm.
2011, 33(12): 3022-3027.
doi: 10.3724/SP.J.1146.2010.01272
Abstract:
Since the PMIPv6 can not be efficiently operated, an improved fast handover scheme based on network- performed prediction is proposed. Without changing the decision-maker, the handover experience is generated to train the learning system. The k-distance weighted nearest neighbor algorithm is employed to predict the next mobile access gateway and the soft forwarding mechanism is employed to protect the receiving packets during the handover. Simulation results indicate that the proposed scheme can achieve better performance in terms of handover latency and packet loss compared with PMIPv6.
Since the PMIPv6 can not be efficiently operated, an improved fast handover scheme based on network- performed prediction is proposed. Without changing the decision-maker, the handover experience is generated to train the learning system. The k-distance weighted nearest neighbor algorithm is employed to predict the next mobile access gateway and the soft forwarding mechanism is employed to protect the receiving packets during the handover. Simulation results indicate that the proposed scheme can achieve better performance in terms of handover latency and packet loss compared with PMIPv6.
2011, 33(12): 3028-3034.
doi: 10.3724/SP.J.1146.2011.00422
Abstract:
A fast mapping algorithm, named Topology Partition Based MAPping (TPBMAP), is proposed considering the energy consumption and traffic balance for the Network-on-Chip (NoC). The proposed algorithm not only generates topology automatically by taking the characteristic of chip layout into consideration, but also achieves the mapping when the number of network nodes is not equal to that of IP cores, using the technology of virtual IP core. Introducing the optimized model, the goal of which is the balance of traffic, the IP cores with heavy traffic are mapped to the edge region to reduce effectively traffic in the center of network. TPBMAP uses iteration of topology partition and makes the IP cores map to the nodes with neighboring in each iteration process, in order to complete rapidly mapping with low energy. According to the experimental results, the proposed algorithm can achieve mapping result with a fast rate, low energy consumption and balanced traffic.
A fast mapping algorithm, named Topology Partition Based MAPping (TPBMAP), is proposed considering the energy consumption and traffic balance for the Network-on-Chip (NoC). The proposed algorithm not only generates topology automatically by taking the characteristic of chip layout into consideration, but also achieves the mapping when the number of network nodes is not equal to that of IP cores, using the technology of virtual IP core. Introducing the optimized model, the goal of which is the balance of traffic, the IP cores with heavy traffic are mapped to the edge region to reduce effectively traffic in the center of network. TPBMAP uses iteration of topology partition and makes the IP cores map to the nodes with neighboring in each iteration process, in order to complete rapidly mapping with low energy. According to the experimental results, the proposed algorithm can achieve mapping result with a fast rate, low energy consumption and balanced traffic.
2011, 33(12): 3035-3039.
doi: 10.3724/SP.J.1146.2011.00441
Abstract:
A fully-integrated SiGe BiCMOS Power Amplifier (PA) is presented for the 2.4 GHz 802.11b/g wireless LAN application. The linearization is improved by the simple HBT-capacitor structure in the adaptively biasing circuit, without additional DC power consumption, chip area and insertion loss. The temperature stabilization is achieved in the HBTs DC base biasing path by negative feed back. This scheme prevents effectively thermal runaway and causes no RF power penalty. The proposed power amplifier is fabricated in 0.18 SiGe BiCMOS process and the chip area is 1.56 mm2 including all the biasing and matching circuits. The measurement results indicate that, in band of 2.4-2.5 GHz, this PA gets the small-signal gain S21 of 23 dB, and the input return loss S11of less than -15 dB. The proposed PA achieves the linear output power of 19.6 dBm, the Power Added Efficiency (PAE) of 20%, and the power gain of 22 dB at the output 1 dB compression point.
A fully-integrated SiGe BiCMOS Power Amplifier (PA) is presented for the 2.4 GHz 802.11b/g wireless LAN application. The linearization is improved by the simple HBT-capacitor structure in the adaptively biasing circuit, without additional DC power consumption, chip area and insertion loss. The temperature stabilization is achieved in the HBTs DC base biasing path by negative feed back. This scheme prevents effectively thermal runaway and causes no RF power penalty. The proposed power amplifier is fabricated in 0.18 SiGe BiCMOS process and the chip area is 1.56 mm2 including all the biasing and matching circuits. The measurement results indicate that, in band of 2.4-2.5 GHz, this PA gets the small-signal gain S21 of 23 dB, and the input return loss S11of less than -15 dB. The proposed PA achieves the linear output power of 19.6 dBm, the Power Added Efficiency (PAE) of 20%, and the power gain of 22 dB at the output 1 dB compression point.
2011, 33(12): 3040-3045.
doi: 10.3724/SP.J.1146.2011.00358
Abstract:
Why a layer of Os film with high work function can increase the emission ability of impregnated cathode notably? This is an undecided important problem for a long time. In this article, based on the emission test and scanning electron microscope analyzing, the Synchronous Radiation PhotoelEctron Spectrum (SRPES) technology is used to measure element composition and chemical states on W-film cathodes and Os-film cathodes. The results indicate, the emission ability of the cathode coated with Os-film is higher than that coated with W-film by 1.65 times, and Os-film can increase the number of barium atom and low binding energy oxygen atom on the surface of cathodes by 40% and 56% comparing to W-film. With further analysis, the low melting point and characteristics apt to resolve for the oxides of Os film, accelerate the transformation of oxygen on cathode surface during activation, thus cause the Os-film cathode surface to get more surplus barium Ba+(a) and to get higher emission ability.
Why a layer of Os film with high work function can increase the emission ability of impregnated cathode notably? This is an undecided important problem for a long time. In this article, based on the emission test and scanning electron microscope analyzing, the Synchronous Radiation PhotoelEctron Spectrum (SRPES) technology is used to measure element composition and chemical states on W-film cathodes and Os-film cathodes. The results indicate, the emission ability of the cathode coated with Os-film is higher than that coated with W-film by 1.65 times, and Os-film can increase the number of barium atom and low binding energy oxygen atom on the surface of cathodes by 40% and 56% comparing to W-film. With further analysis, the low melting point and characteristics apt to resolve for the oxides of Os film, accelerate the transformation of oxygen on cathode surface during activation, thus cause the Os-film cathode surface to get more surplus barium Ba+(a) and to get higher emission ability.
2011, 33(12): 3046-3050.
doi: 10.3724/SP.J.1146.2010.01367
Abstract:
Owing to the better security, dynamic and extensibility, Exclusion Basis Systems (EBS) based key management applies to security of heterogeneous sensor networks, but it suffers from the collusion. This paper introduces a Minimum Spanning Tree (MST) based optimization scheme of key collusion restraining, which uses Prim algorithm to create MST from undirected graph constituted by nodes in cluster. Traversing the tree gets a sequence of nodes. The sequence is used to design and distribute keys in the scheme. It improves the repeated degrees of keys in adjacent nodes and reduces the possibility of key collusion. The experimental results show that the optimization scheme effectively improves the resistant of networks capture, comparing with SHELL and random distribution method.
Owing to the better security, dynamic and extensibility, Exclusion Basis Systems (EBS) based key management applies to security of heterogeneous sensor networks, but it suffers from the collusion. This paper introduces a Minimum Spanning Tree (MST) based optimization scheme of key collusion restraining, which uses Prim algorithm to create MST from undirected graph constituted by nodes in cluster. Traversing the tree gets a sequence of nodes. The sequence is used to design and distribute keys in the scheme. It improves the repeated degrees of keys in adjacent nodes and reduces the possibility of key collusion. The experimental results show that the optimization scheme effectively improves the resistant of networks capture, comparing with SHELL and random distribution method.
