最新刊期
卷 40 ， 期 3 ， 2012
- 摘要：Aiming at dealing with the problem of azimuth prefiltering during the interferometric processing procedures,this paper proposed an improved method for InSAR azimuth prefiltering.Based on the theoretic analysis of the InSAR imaging geometry and the principles of coherence,this paper proposes that only the radar echoes coming from the space sampling positions with the same azimuth angles are coherent,i.e.,available for interferometric process.Then an improved method for InSAR azimuth prefiltering is proposed according to the same azimuth angle extension.Finally,The computer simulation and practical examples analysis are shown to prove that the proposed algorithm can improve the coherence between complex SAR images while preserving the coherent information effectively.关键词：SAR interferometry(InSAR);azimuth prefiltering;coherence;azimuth angle2|2|2更新时间：2025-07-16
- 摘要：A novel method based on summation and difference sequence of ranges is proposed in order to extract micro-motion signatures of targets with complex motions which are composed of translation and vibration.The method estimates summation and difference of ranges from one dimensional range profile and obtains summation and difference sequence of ranges from time-range profiles of targets.Vibration amplitudes and vibration periods of different scatterers are achieved and translation ranges of targets are exactly acquired from summation and difference sequence.The restrictive conditions of the method were analyzed and simulation experiments were carried out.Simulation results validate the theoretical analysis and the signature extraction method.The method discussed in the paper can be extended to analyze other targets with general translation and other periodic motions.关键词：range profile;summation and difference sequence;micro-motion;signature extraction2|2|7更新时间：2025-07-16
- 摘要：Based on the approximate sparsity of speech signal in discrete cosine basis, this paper proposes a new algorithm of compressed sensing of speech signal based on special row echelon measurement matrix and dual affine scaling interior point reconstruction method.This algorithm can resolve the problem of inaccuracy of location of reconstruction coefficient which is zero or nearly zero of compressed sensing based on Gaussian measurement matrix and linear programming to some extent.The reconstruction performance of this algorithm is analyzed theoretically.The simulation results of compressed sensing of speech signal show when the reduction ratio(the ratio of numbers of measurements and original samples) is 1∶4 based on the discrete cosine basis,the average SNR of reconstruction signal based on the special row echelon measurement matrix is 9.73 dB higher than the Gaussian measurement matrix,and the average MOS score of reconstruction signal based on the special row echelon measurement matrix is 1.22 higher than the Gaussian measurement matrix.关键词：compressed sensing;discrete cosine basis;measurement matrix;row echelon matrix;dual affine scaling interior point method2|2|13更新时间：2025-07-16
- 摘要：T/R-R high frequency surface wave radar (HFSWR) can detect over-the-horizon sea targets which are hundreds of miles away.The earth curve should be taken into consideration when determining target position using the measurement information obtained by HFSWR.We present sphere positioning algorithm to calculate target position and corresponding accuracy.Weighted least square (WLS) method is applied to sphere positioning algorithm to improve positioning accuracy.Computer simulations are leaded to analyze deviation of target position obtained by plain positioning algorithm.GDOP of sphere positioning algorithm using WLS method is also simulated.We conclude that sphere positioning algorithm can eliminate position deviation.Besides,sphere positioning algorithm using WLS method improves target positioning accuracy.关键词：high frequency surface wave radar (HFSWR);sphere positioning algorithm;weighted least square algorithm2|2|2更新时间：2025-07-16
- 摘要：Based on B-valuation and by defining probability measure in Boolean evaluation lattice and set of all formulae respectively,the B-probability truth degree of formulae in Boolean semantics is introduced using the integral method,then the probability logic metric space is established in Boolean semantics,the approximate reasoning of quantitative logic methods have been extended to Boolean semantics,the graded method of Boolean semantics is improved.关键词：Boolean algebra;B-valuation;B-probability truth degree;probability logic metric space;approximate reasoning2|2|4更新时间：2025-07-16
- 摘要：Space information networks,which have become a popular research focus,are a new type of self-organizing network constituted by information systems of land,sea,air and space.A clustering algorithm for space in-formation networks was proposed to enhance network scalability.Analytic hierarchy process (AHP) was used to select cluster heads,and then nonoverlapping k-hop clusters could be formed.With taking node mobility and cluster equali-zation of space information networks into account,mobile agents were used to migrate and duplicate functions of cluster heads in a recruiting way.Dynamical maintaining mechanisms like cluster merger/partition,reaffiliation and adaptive adjustment of information update period were also designed.Simulation results show the proposed clustering algorithm is suitable for use in space information networks and it can improve network scalability.关键词：space information networks;self-organizing networks;clustering algorithm;AHP;mobile agent2|3|1更新时间：2025-07-16
- 摘要：We propose a method to estimate the InSAR (synthetic aperture radar interferometry) interferometric phase based on the model of correlation coefficient weight data vector.In the method,the idea of correlation weight joint single pixel is introduced.Benefiting from the correlation coefficient weight data vector,the method can take advantage of the coherence information of neighboring pixel pairs to auto-coregister the SAR images and reduce the interferometric phase noise simultaneously.Theoretical analysis and computer simulation results show that the method can provide accurate estimate of the terrain interferometric phase (interferogram) even if the coregistration error reaches one pixel.The effectiveness of the method is verified via simulated data.关键词：interferometric synthetic aperture radar (InSAR);coregistration error;interferometric phase;joint single pixel;correlation coefficient weight2|2|2更新时间：2025-07-16
- 摘要：P2P streaming applications develop quickly with the enhancement of PC's performance and network bandwidth.In this paper the system model and the maximum data transmitting rate of P2P streaming system were studied.We presented a system model of P2P streaming system under stable state,which could capture the characteristic of the system by a few parameters.The maximum data transmitting rate of the stable system was derived and proven,and a centralized algorithm named WFSOT was designed to organize nodes into an overlay quickly which could support the maximum data transmitting rate and allocate nodes' practicable bandwidth.At last,we discussed several aspect of the WFSOT algorithm,especially the node's depth in the overlay topology.关键词：P2P streaming;data transmitting rate;topology architecture;bandwidth allocation;node depth2|2|1更新时间：2025-07-16
- 摘要：In the current research on face recognition,facial geometric features have not been fully utilized.Thus,the importance of geometric features in face recognition is explicated,and a novel technique of facial geometric feature extraction is proposed.Then a facial explicit feature is constructed based on the fusion of geometric and texture information.The corresponding face recognition method using these features is also given.This novel face recognition method not only possesses some advantages over the popular subspace methods based on statistical learning,but can be a complement to the latter.Experiments demonstrate that the extracted features and the corresponding face recognition algorithm are robust to facial expression and environmental illumination variations.关键词：face recognition;explicit feature;geometric feature;Hausdorff distance2|2|3更新时间：2025-07-16
- 摘要：To enhance the quality of the restored signal extracted from short-sampled paths,this paper proposed a novel blind extraction method based on time structure.By replacing negentropy with the sum of autocorrelation statistically obtained at multiple delays as the objective function,and introducing the closeness between output signal and reference signal as well as output's variance as the constraints of non-linear programming,besides incorporating the Newton-like iterative method,a novel iterative expression was successfully deduced to extract one-path signal.In addition,a novel criterion to evaluate the short samples is presented.Simulation showed that,whatever the length of observed multiple signals is,as long as the short-duration component is contained,the proposed method can extract the useful signal in high quality.关键词：blind extraction;time structure;negentropy;newton-like iterative method;short-sampled2|2|2更新时间：2025-07-16
- 摘要：Based on a convex total variation (TV) variational energy function,this paper proposes a wavelet based variational model to remove multiplicative noise.Using convex optimization tool,we give an alternating split Bregman algorithm to solve the proposed model.Compared with existing TV based method,the proposed algorithm is simple and can be extended easily.Numerical experiments are presented to demonstrate the efficient performance of the proposed algorithm and its extensions.关键词：multiplicative noise;besov space;wavelet;curvelet;variational model2|2|6更新时间：2025-07-16
- 摘要：A new method is proposed aiming at decoding De Bruijn color encoded structured light images with high precision.This method is composed of the central color stripe identification based on gradient analysis,the color classification based on clustering analysis and the feature point matching based on double-gradient and multi-pass dynamic programming.The method can be applied to avoid color interference effectively in the encoded structured light images containing parallel pixel lines with different colors.Moreover,by making full use of local neighborhood information,the method can match every feature point.Experimental results show that the proposed method effectively improves the decoding accuracy without assuming that the surface of the target object is monotonous or restricting its continuity,and also exhibits good robustness.关键词：color structured light;De Bruijn coding;clustering analysis;dynamic programming;decoding structured light2|2|9更新时间：2025-07-16
- 摘要：Modular inversion is the most complex and time consuming finite fields arithmetic operation in elliptic curve cryptography (ECC).Further more,the hardware implementation of modular inversion is difficult.Based on signed digit system theory,this paper presents a scalable dual-field Montgomery modular inversion algorithm which supports inversion algorithm of any precision parameters in the prime fields and binary fields.According to the algorithm,the hardware architecture is designed and analyzed in area complexity and time complexity.Simulation results show that the hardware design is superior to other hardware designs in operation speed,circuit area and flexibility.关键词：elliptic curve cryptography;signed digit system;scalable;dual-field;modular inversion2|2|3更新时间：2025-07-16
- 摘要：Gyrotrons are high power millimeter-wave and terahertz radiation sources and have a broad range of applications to terahertz science and technology.The research of 0.6THz gyrotron with an axis-encircling electron beam operating in the TE37 mode and third harmonic is presented according to the linear theory and nonlinear self-consistent theory of gyrotrons.And mode competition with the electron guiding center radii of 0mm and 0.315mm has been studied,respectively.The gyrotron operation at 55kV beam voltage and 1A beam current can generate 4.73kW output power at the frequency of 0.6 THz.关键词：gyrotron;terahertz;high-harmonics2|2|3更新时间：2025-07-16
- 摘要：To solve the selection problem of Tikhonov regularization parameter in electrical capacitance tomography,A method is proposed to get an optimal regularization parameter using Morozov discrepancy principle,which make the (output) error due to regularization equals the error level in the data.To get an optimal regularization parameter rapidly and reasonably,a hybrid algorithm by combining three-order convergence algorithm and two parameter model is proposed.Numerical experimental results show that regularization parameter selection affects both the reconstruction speed and quality;the proposed hybrid algorithm has high image reconstruction speed and high accuracy for different flow patterns.关键词：electrical capacitance tomography;image reconstruction;two parameter model;three order algorithm;Morozov discrepancy equation;hybrid algorithm2|2|2更新时间：2025-07-16
- 摘要：The virtual array of multiple-input multiple-output (MIMO) radar could be divided into multiple subarrays with the same geometric configuration but different locations.Based on the rotation invariance property of these subarrays,a low complexity 2-D DOA estimation method for MIMO radar is presented in this paper.For each target,multiple 2-D DOA estimates are obtained by applying a pre-projection based ESPRIT algorithm to different subarray combinations.Then,the estimates of each target are fused via Kalman filtering to improve the estimation accuracy.Moreover,sample multiplexing based on the symmetric data structure of MIMO radar further improves the estimation accuracy.Numerical examples demonstrate the effectiveness of the proposed method.关键词：MIMO radar;2-D DOA;ESPRIT;Kalman filter2|4|6更新时间：2025-07-16
- 摘要：Nonlocal means exploits the spatial correlation in an image,and preserves the structure information effectively.Combining the nonlocal patch regularization with TV regularization,we propose a nonlocal patch regularized image restoration model.The improved structure tensor matrix can be used to achieve a data-adaptive weigh function,which can then adjust the similarity match process based on the local structure of a pixel.A more simple and effective algorithm -Split Bregman,is used to solve the model iteratively.Compared with other regularization models,our method performs better in improving the quality of restoration image and the efficiency of the algorithm.关键词：image restoration;nonlocal means;regularization;split Bregman2|2|3更新时间：2025-07-16
- 摘要：From the point of view of information hiding,traditional visual cryptography scheme (VCS) is not an efficient method.It can only share a small sized secret image due to the large pixel expansion.A (t,k,n) multi-threshold image secret sharing scheme is proposed to increase the amount of hidden information.A grayscale secret image is hidden in a VCS to guide the choice of share matrices.In the first phase of the reconstruction process,any t participants can stack their shadow images to decode a vague secret image by human visual system.In the second phase,any k participants can extract additional information hidden in their shadow images,and reveal a precise grayscale secret image by computation.Compared with the traditional VCS,the proposed scheme can hide more information of the grayscale secret image,and has smaller size expansion without deteriorating the visual quality of the revealed image of VCS.关键词：information hiding;image secret sharing;visual cryptography;multi-threshold scheme2|3|5更新时间：2025-07-16
- 摘要：Registration method based on optical flow model is very suitable to time-sequence images,but the assumption of constant brightness at a point makes it only be used to make registration for signal-modal images.So an exact histogram specification method is proposed to transform MR-PD model to MR-T2 modal before registration based on optical flow model.If the difference between two images is large the registration result could not be ideal because this registration method is mainly used to correct the light deformation between time-sequence images,so information which reflects the structural feature of image is taken to improve optical flow model,that is,image landmarks are utilized to produce an additional external-force for optical flow model to get ideal registration parameters.Experimental results demonstrate that the improved method can realize accurate registration of multi-modality time-sequence MR images between which there is large difference.关键词：image registration;optical flow model;histogram specification;landmarks2|3|19更新时间：2025-07-16
- 摘要：A classification algorithm FlowCopySearch (FCS) is developed that systematically profiles static intrusion signatures and network traffic to generate a high performance and memory-efficient packet classification tree.The improvements are two folds.Firstly,the best classification tree is formally defined and packet feature entropy is proposed to measure how well a packet field can partition the traffic.Secondly,FCS copies a rule set for a flow instead of traditionally copying the rule set for every packet in the flow,so the classifying speed is increased considerably.The experiment results show that in backbone trace FCS is preferred.Compared to the other two classical algorithms,FCS can not only speed up classification by as much as 10.1%~45.1% in speed,but also save memory consumption of 11.1%~36.6% at the same time.关键词：intrusion detection system;packet feature entropy;heavy hitter5|3|2更新时间：2025-07-16
- 摘要：Dispersion characteristics of square and triangular metallic photonic crystals filling with plasma are investigated by finite difference time domain(FDTD) method.Effects on TM and TE modes in the two-structures with the variation of plasma density are analyzed.The results show that the dispersion curves of 2-D metallic photonic crystal filling with plasma upshift to the higher frequency .The width and location of bandgap of TM and TE modes can be controlled by the density of plasma.These properties of the 2-D Metallic Photonic crystal with background are potentially valuable in the aspect of designing tunable photonic crystal device.关键词：2-D metallic photonic crystal;plasma;photonic bandgap;dispersion property2|2|2更新时间：2025-07-16
- 摘要：A broadband dual-band dual-polarized (DBDP) shared-aperture array operating at X- and S- bands for the synthetic aperture radar (SAR) application is presented.Tri-resonance is introduced in the lower frequency element to broaden its intrinsic narrower bandwidth.Furthermore,several methods are employed to enhance the polarization isolation in both bands.VSWR≤2 bandwidths of 13.1% and 11% are measured in X- and S- band,respectively,where in-band array isolation and element isolation are better than 37dB and 28dB.The measured radiation patterns match well with the theoretical ones while the cross-polarization level is suppressed under -27dB within mainlobe;the X-band scan ability of ±27° is also confirmed by the measurement.关键词：broad band;high isolation;dual-band;dual-polarization;shared aperture;microstrip array;non-integral frequency ratio;SAR antenna4|3|4更新时间：2025-07-16
- 摘要：Nature-inspired computation (NIC) is a heuristic optimization concept and a novel thinking pattern of computational intelligence by imitating various operating mechanisms effectively in nature.This paper studies the relationship between unification and diversity of NIC models from the dialectical perspective of natural philosophy.First,a kind of general framework for studying NIC is proposed;Second,all kinds of existing NIC models are systemic summarized in this paper,from inspiration source to research branch,from computing models to their applications,from hardware-software implements to computer development,as well as other aspects;Finally,based on the proposed unification concept of NIC models,calculation principle and analysis framework of the unification of NIC is refined and presented.关键词：nature-inspired computation;computational intelligence;thinking model;unification4|4|13更新时间：2025-07-16
- 摘要：The goal of quality assessment research is to design algorithms for objective evaluation of quality in a way that is consistent with subjective human evaluation.Based on the human visual system(HVS) with different sensitivities in the frequency domain,low frequency coefficient error and high frequency coefficient error are calculated by different methods.The product of two errors is adopted as objective evaluation of quality.The new method is validated with subjective quality scores on LIVE database which containing 982 images.Experimental results show that the performance of the new method is superior to the algorithms of PSNR,LMSE and SSIM.关键词：image quality assessment;wavelet transform;wavelet second coefficient error(WSCE);differential mean opinion score(DMOS)2|3|1更新时间：2025-07-16
- 摘要：With the evolving of the network technologies,there has been a growing interest in the end-to-end multipath transfer.This paper investigates the optimal flow control based multiple end-to-end paths and proposes a distributed algorithm to optimally allocate the network resource.The algorithm achieves efficient bandwidth allocation by taking the path diversity into consideration.The algorithm proposed is shown to be asymptotically global stable in the absence of the propagation delay.The simulations demonstrate the rapid convergence and practicality of the algorithm.关键词：end-to-end multipath;optimal flow control;stability;utility maximization;path diversity2|2|3更新时间：2025-07-16
- 摘要：A new technique based on the pattern synthesis is proposed to analyze the electromagnetic environments of phased arrays.This article analyses the radiation properties of phase arrays,especially large phased arrays,to provide a precise and efficient method for the electromagnetic compatibility design.关键词：phased array;electromagnetic environment;electric field intensity;power density3|2|7更新时间：2025-07-16
- 摘要：This paper addresses range-spread target detection in spherically invariant random vector clutter.The modified scatterer density dependent(MSDD)detector is introduced,and the analytic expression relating false alarm probability to detection threshold is deduced.MSDD need to estimate the number of scatterers,and its performance degradation gracefully when there is a mismatch.To improve the robustness of MSDD,a detector based on ordered data variability(ODV)is proposed.The results show that ODV-MSDD is robust for various target range extent,and its detection performance is improved when increasing the number of scatterers,sensors and spiky of the clutter.Compared with the MSDD,ODV-MSDD estimates the number of scatterers adaptively,and it can improve performance and robustness of detector effectively.关键词：Target Detection;non-Gaussian clutter;variability index(VI);ordered data variability(ODV)2|2|1更新时间：2025-07-16
- 摘要：The joint calibration method of mutual coupling and gain-and-phase errors based on covariance matching estimation technique (COMET) are proposed for the uniform linear array (ULA).According to the cost function of the COMET and the errors model of the ULA,an alternative iteration algorithm is presented to optimize all the unknown parameters.In order to avoid the complicated step concerning the DOA estimation in each of iteration,an improved alternative iteration algorithm is presented to reduce the computation complexity via making use of the Toeplitz structure of the covariance matrix for the ULA.Compared with the errors calibration methods based on subspace technique,the two novel algorithms are capable of directly exploiting the time-domain statistical characteristic of the sources and are applicable to different Gaussian noise models,e.g.,the case of nonuniform noise power.The simulation experiments validate the effectiveness and advantage of the novel algorithms.关键词：array errors calibration;uniform linear array (ULA);mutual coupling;sensor gain-and-phase errors;Toeplitz matrix;covariance matching estimation technique (COMET)2|2|8更新时间：2025-07-16
- 摘要：Electromagnetic compatibility is a question when several radars work together.The performance of an air surveillance radar degrades significantly due to impulsive interference generated by rival cochannel radar transmitter.This paper proposed a novel constant-false-alarm-rate (CFAR) detection based impulsive interference mitigation algorithm according to the interference features.With cell average (CA) for adaptive thresholding and logical judgment for interference locating,the interference detection is more robust.What's more,the time-domain cancellation removes the impulsive interference while preserving the fidelity of the clutter component,or the leakage of strong clutter returns desensitizes the radar.The validity of the algorithm is verified by field experimental data.关键词：air surveillance radar;impulsive interference;CFAR detection;interference mitigation;electromagnetic compatibility2|3|0更新时间：2025-07-16
- 摘要：When to measure the incidental PM at AM,because in time domain and frequency domain,AM and PM are accompanied but not independent,so it's difficult to measure incidental PM.Traditional method by spectrum analysis is complex,and is only applicable to situation with small PM index.A new method is proposed:Under a particular frequency Relationship,by digital vector demodulation and sampling,to transform the AM and PM to magnitude error and phase error in IQ domain independently,on the measurement rules,there is analytical relationship between digital demodulation phase error and the analog incidental PM.For a total of 120 cases of parameters combination,experiment is carried out;the measurement results confirmed that the method is accurate.关键词：incidental phase modulation;measure;vector analysis;phase error2|2|0更新时间：2025-07-16
- 摘要：A new idea for forensic speech information hiding using three-cycle fractional cosine-cepstrum transform (3DFCCT) is proposed.We find in our analysis that the 3rd parameter of FRCT presents property of high frequency,then we put forward the low bit embedding and the over zero rate detection method for embedding secret information into speech signal in 3DFCCT domain.Results of simulation indicate that it has certain ability for anti-jamming.The discoveries in our study provide a new thought for application of 3DFCCT in forensic speech information hiding.关键词：fractional cosine-cepstrum transform;forensic speech information hiding;zero-crossing rate detector2|2|3更新时间：2025-07-16
- 摘要：This paper proposes a framework to efficiently support dynamic,fine-grained access control for the very loosely structured data model,named GLSDM(General very Loosely-Structured Data Model),which is presented based on the current dataspace data models.In the framework,GLSDM is mapped into and stored in relational databases,and then the fine-grained access control in GLSDM is converted into the corresponding fine-grained security (e.g.,row-level and cell-level security) in relational databases.A query rewriting algorithm is also given to dynamically imbed GLSDM security information into SQL statements the user issues,thus,dynamic access control is realized during the period of query processing.Finally,the validity of the framework is proved by theory and experiment,that is,the GLSDM-to-relational mapping method and query rewriting algorithm in this paper can ensure the access control in GLSDM is equivalent to that in relational databases.关键词：access control;dataspace;relational databases;loosely structured2|3|2更新时间：2025-07-16
- 摘要：The digital modulation signal is usually encountered in five kinds of distortion factors,including I/Q gain imbalance,phase offset,continuous wave interference,phase noise and additive Gaussian noise.Through mathematical derivation,a complete mathematical formula is obtained,to calculate EVM by five distortion factors.At the same time,two experiments are carried out,in conjunction with numerical simulation to verify the formula.Formula and measurement results fit well.关键词：error vector magnitude;distortion;formula;experiment4|2|2更新时间：2025-07-16
- 摘要：An approach is proposed for fabric defect detection based on the improved conventional pulse coupled neural network (PCNN) model.For these too many parameters of conventional PCNN,it is difficult to get the adaptive parameters.The problem can be solved in the proposed way,in which optimal number of iteration to segment fabric defect image automatically is determined based on minimum difference of uniformity within region.Segmentations on various defect images are implemented with the proposed approach and the experimental results demonstrate its reliability and validity.关键词：pulse coupled neural network(PCNN);fabric defect;image segmentation;uniformity within region2|2|7更新时间：2025-07-16
- 摘要：The algorithm for semantic similarity of short text is used widely in document retrieval,information extraction and text mining.An algorithm for semantic similarity of short text named ST-CW is presented.The algorithm calculates semantic similarity of concept based on WordNet and The Brown Corpus,and then a formula is presented which refers to both concept similarity and syntactic information in short text.The evaluations are conducted on R&B and Miller dataset.关键词：semantic similarity of short text;WordNet;corpus-based method2|2|19更新时间：2025-07-16
- 摘要：The traditional location methods for passive localization are TDOA (Time Difference of Arrival) based due to the unknown TOE (Time Of Emission).Based on Bancroft's algorithm,which was developed for GPS single-point position,the TOA least squares (TOA-LS) estimation algorithm for passive multilateration is proposed.The TOA-LS equations are composed of three linear equations whose coefficients are dependent on the target position and TOE.Using Bancroft's algorithm with some initial values,the TOA-LS algorithm solves the linear equations for new solutions and updates their coefficients.Simulation experiments demonstrate that the TOA-LS algorithm is near optimal and attaining the theoretical lower bound for targets in different geometric positions.关键词：Bancroft's algorithm;multilateration;time of arrival (TOA);least square method2|2|1更新时间：2025-07-16
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0