最新刊期
卷 29 ， 期 3 ， 2001
- 摘要：In this paper,based on the ordinary singular value decomposition,a quantitative correspondence of the singular values and singular vectors between the row or column symmetric matrix (namely,the extended matrix) and its original (a.k.a mother matrix) is derived,and the perturbation analysis for the extended matrix is provided accordingly.Theoretical predictions and numerical evidences indicate that,for a class of extended matrices,the singular value decomposition using the mother matrix rather than the extended matrix per se can save dramatically the memory and alleviate considerably the computational burden without loss of any numerical precision.关键词：singular value decomposition;mother matrix;extended matrix;perturbation analysis;time-frequency distribution;signal processing0|2|10更新时间：2025-07-02
- 摘要：Gene chip is a kind of microarray with high density of oligonucleotide.In this paper,we present a new approach of gene chip design,by which an optimum set of oligonucleotide probes can be generated using dynamic programming.The probes have nearly the same melting temperature Tm,and are of variable length and variable overlap.The methods of designing gene chips detecting DNA mutation or SNPs are also proposed in this paper.关键词：gene chip;probe design;dynamic programming0|2|5更新时间：2025-07-02
- 摘要：A non-parametric algorithm for DOA estimation with high-resolution is presented based on a single snapshot from a sensor array and a well-designed beam-space pre-processor.The iterative de-convolution processing utilizes the sparsity constraint.Numerical results illustrate that the algorithm converges to the DOA estimate with high-resolution in a few iterations.关键词：single snapshot;beam-space;sparsity constraint;DOA0|2|0更新时间：2025-07-02
- 摘要：Based on research of so-called space-time DOA matrix method,we propose several of its improved and generalized forms in this paper.The theoretical analysis and simulation show that,being a novel space-time eigenstructure based approach for 2-D high-resolution DOA estimation,the method is capable of producing a large amount of virtual elements in space-time domain by space-time processing.Therefore the constraint over the array configuration can be significantly weakened,and many array forms and corresponding estimation approaches,which perform better noise suppression ability and more feasibility,can be flexibly generalized.关键词：antenna array;smart antenna;DOA;space-time processing0|2|20更新时间：2025-07-02
- 摘要：A new method for anti-reverberation based on WVD-HT(Wigner Ville Distribution & Hough Transform) is presented.The brief introduction,main operation and processed results are given.The simulation results show that this new method can detect the signal corrupted by the reverberation and estimate its parameters effectively.关键词：Wigner-Ville distribution;Hough transform;reverberation0|2|8更新时间：2025-07-02
- 摘要：The problem of target detection in the cluttered circumstance with wide-band high-resolution radar is studied.A high-resolution polarization target detection method is presented based on intense scatterer integration.With the intrinsic high resolution of wide-band waveform,one-dimension range profile of radar target can be obtained.In connection with target's polarization characteristic,the number and distribution of intense scatterer in radar echoes can be estimated.SCR(Signal-to-Clutter-Ratio) can be improved efficiently by integration of these intense scatterers in resolution cells.Simulated experimental results show that radar's detection performance can be improved significantly by using the algorithm presented in this paper.关键词：high-resolution;polarization;Target Detection0|2|7更新时间：2025-07-02
- 摘要：In bearings-only tracking,observer maneuver is critical to ensure observability and to obtain an accurate target localization.In this paper,the author presents an adaptive observer maneuver control approach based on minimizing the GDOP of target localization,in order to achieve the best estimation accuracy at each second of localization process.The approach for optimizing observer course in target tracking is verified to be the same as in target location.关键词：passive localization and tracking;TMA;observability;estimability0|2|8更新时间：2025-07-02
- 摘要：Similar to the migration in domain of seismic techniques,this paper presents an approach to focus on the ground-penetrating radar (GPR) data and estimate the electromagnetic wave velocity underground.To demonstrate the validity and feasibility of this approach,experimental GPR data are obtained with object buried in two different kinds of media.It is found that in homogeneous medium,this approach can be used to estimate the electromagnetic wave velocity underground and improve the imaging resolution.关键词：ground-penetrating radar;migration;Velocity estimation;velocity spectrum0|2|16更新时间：2025-07-02
- 摘要：Many of the despeckling processing methods on SAR image are available currently,which have advantages and disadvantages,respectively.None of them is generic.In this paper,an analysis and comparison about them is introduced in detail.An improvement of SA method is proposed and some important conclusions are acquired.A series of experimental results about image processing somewhere in Pohai are obtained.关键词：image despeckling;speckle model;RCS model;correlated neighborhood model;structured neighborhood mode;simulated annealing0|2|1更新时间：2025-07-02
- 摘要：A new method of reducing speckle noise for SAR(synthetic aperture radar) image is proposed,which combines wavelet transform and adaptive Wiener filter based SAR image scene heterogeneity.It can better preserve clutter edge and point target.The several probability density functions of SAR are analyzed after speckle is de-noised and target detection is studied .A new target detection method and its realizing are proposed.The validity of the method is proved by experiments for real SAR image.0|2|4更新时间：2025-07-02
- 摘要：This paper studies the design of two-channel regular orthogonal principal component filter banks.A type of the parametric representation of the regular product filters is proposed,by which the optimal problem is transferred into a standard LSIP.And an efficient feasible solution iteration algorithm is given for the single and double parameter cases.关键词：principal component filter bank;regular order;feasible solution iteration algorithm0|2|0更新时间：2025-07-02
- 摘要：Maneuver detection is critical especially for tracking of short range target.Former methods deal with target as a point,however,it is proved that the use of information from an image sensor can improve the quality and reliability of maneuver detection.In this paper,we introduce an infrared image processing method with the application of wavelets,in which multi-scale basis selection is based on class separability got from a recurrence process from initial classification to final classification.We also introduce a method of line extraction to estimate three centers of target.This algorithm keeps relatively fine performance even in low SNR environment.关键词：class separability;wavelet packet;K-means clustering;smooth filtering;line extraction;maneuver detection0|2|1更新时间：2025-07-02
- 摘要：The method of moments is used to analyze and calculate the broadband characters of impedance,voltage satanding wave ratio(VSWR),gain and radiation pattern of larger angle LPDA,and the relation between these characters and the parameter of antenna construction is discussed in this paper.Based on analysis and calculation,the antenna is designed and tested,and the measured results are in good agreement with the theoretical calculation.关键词：the method of moments;LPDA;angle;the broadband characters0|2|2更新时间：2025-07-02
- 摘要：Using the thought of multiscale analysis,we combine the model-based analysis method with the multiscale signal transformation method and propose a new algorithm of multiscale fusion estimation based on multi-sensor single model.At each scale we have obtained the fusion estimates by use of all sensors at finer scales,which can be effictively used for data fusion estimation for dynamic systems with multi-sensors at multirate sampling.关键词：multiscale analysis;wavelet transformation;Kalman filtering;multiscale estimation0|2|14更新时间：2025-07-02
- 摘要：The complexity of various environmental disturbances should be considered in applied multisensor systems, but the research of multisensor data fusion under complicated disturbing environment has not been carried out yet.So,this paper presents a Markov model of multisensor system under complicated disturbing environment,and provide state transition diagram and state probability.According to this model,four decision rules of multisensor fusion detection under complicated disturbing environment are deduced.Furthermore,the paper provides simulation results,and analyses detection probability and false probability.关键词：data fusion;Markov model;distributed detection1|3|2更新时间：2025-07-02
- 摘要：This paper presents a local optimization algorithm for computation of 2-D optical-flow field aiming at the specialty of heart-echocardiograph image.We have analyzed several advantages of Zernike moments such as orthogonality and rotation-invariance,and demonstrate that Zernike moments are superior in representing the local motion invariance in heart-echocardiograph image.Accordingly,we generalize the premise of traditional Optical Flow Computation that intensity is invariant in the sequence to the invariance of each order Zernike moment.In addition,in virtue of the computation of whole contribution of the neighborhood around each pixel,Zernike moment based method can greatly reduce the influence of a singular error at one pixel on the total representative,therefore improves the robustness of the algorithm.关键词：optical flow computation;Zernike moments;local optimization;dynamic image sequence analysis0|2|1更新时间：2025-07-02
- 摘要：The aim of this study is to investigate theoretically the possibility for activation of small mammalian myelinated nerve fibers without activating larger ones when stimulating a nerve fiber bundle with a monopolar point electrode using biphasic pulses,which can reduce the electrochemical damage resulted from stimulation pulses to nerve fibers.A simulation system for studying the electrical properties of mammalian myelinated nerve fibers was built based on a simple infinite and homogeneous volume conductor model.By use of an asymmetric but charge-balanced stimulation waveform,the sensitivity of excitation and blocking threshold of nerve fibers to fiber diameter,electrode-fiber distance was calculated.The results show that selective activation of small mammalian myelinated fibers may be possible in a region at some distance from the electrode using biphasic pulses.关键词：neuroelectrical stimulation;selective activation;biphasic pulses0|2|2更新时间：2025-07-02
- 摘要：Radio-frequency interference will cause severe degradation on satellite communications link performance,and adaptive nulling antenna is an effective anti-jamming measure for communication satellite.This paper presents a comparative analysis of various adaptive beamforming schemes when used with multiple-beam antennas.The results of analysis and simulation show that both DMI and RLS algorithms offer the advantages of faster convergence rates and better SINR performance over simple LMS algorithm.These fast algorithms are quite proper to cope with undesired interference signals in an operational satellite communication environment.关键词：adaptive beamforming;adaptive algorithm;communication satellite;multiple beam antenna;radio frequency interference0|2|4更新时间：2025-07-02
- 摘要：In this paper,a hierarchical blackboard model for intelligent fusion system of communication intercept information is brought forward.The architecture of this blackboard model and its implementation method are discussed,and some key algorithms and an application example are presented.The universality of this model in such kind of problem,in which the relation among all sub-blackboards tends to be hierarchical,is pointed out finally.关键词：blackboard model;Information fusion;communication electronic warfare;communication intercept information0|2|4更新时间：2025-07-02
- 摘要：Based on the vector radiative transfer theory,the theoretical model of foil clouds with complex structure and great number has been built.Monte Carlo method is presented to study the scattering from the mumerous and high denseness foil clouds,which is for the first time to show the bistatic RCS of foil clouds with distributing of tropism and high density.关键词：foil clouds;multiple scattering;vector radiative transfer theory;Monte Carlo method0|2|2更新时间：2025-07-02
- 摘要：A Time-Domain Finite-Surface Method is generalized to scattering problems of arbitrary cross section perfectly electrically conducting (PEC) cylinder coated with composite chiral medium.Time domain basic equations are built for solving electromagnetic problem in composite chiral medium.The body-fitted orthogonal grids and the second order absorbing boundary conditions,which are suitable for orthogonal coordinates,are utilized. More accurate results are found.Numerical Results have been obtained for RCS problems of typical PEC cylinders coated with achiral and composite chiral medium.Comparisons with exact series solution show generally good agreement.关键词：time-domain finite-surface method;composite chiral medium;arbitrary cross section;body-fitted orthogonal grid;absorbing boundary condition0|2|1更新时间：2025-07-02
- 摘要：The simultaneous time-space discretization of the telegrapher equations is a primary approach for the transient analysis of transmission lines,which has ever been regarded as brute-force,inefficient and of little value in practice.The study presented in this paper gives an opposite conclusion.By the utilization of the wave propagating property of the voltages and currents on the lines,we prove that this approach can be used as efficiently as the prevailing methods employing rational approximation and recursive convolution such as AWE to general dispersive,nonuniform and coupled lossy transmission lines.A technique to eliminate the spurious oscillations resulting from the space discretization of the telegrapher equations is given.Numerical experiments have been performed and the results show that the method is valid and efficient.关键词：VLSI interconnects;transmission lines analysis;circuit simulation0|2|10更新时间：2025-07-02
- 摘要：The high frequency(HF) characteristics of the split cavity oscillator with three cavities are studied.Starting from homogeneous scalar Helmholtz's equations associated with Borgnis potential function in a cylindrical coordinate system,and based on the standing wave concept of slow-wave introduced in the paper,the analytic expressions of the dispersion relation and field distribution for azimuthally symmetric transverse magnetic modes in the split cavity oscillator with three cavities are derived,by using boundary conditions for Borgnis potential function in conjunction with field matching conditions at the common interface between the adjacent subregions.The resonance frequency of the split cavity oscillator with three cavities calculated by this analytic method is compared with that measured in experiments and it is found that they are in agreement quite well.关键词：split cavity oscillator;dispersion relation;field distribution;high frequency characteristics0|2|2更新时间：2025-07-02
- 摘要：Due to their micro operating current and exponential nature,the subthreshold MOS transistors are suitable to implement current-mode micro-power externally linear circuits.In this paper,a novel current-mode four-quadrant multiplier is proposed and the design techniques and considerations on basic modules for low-voltage micro-power applications,such as filters,oscillators,etc.,are given.To verify the performance,a PLL is designed and simulated as an example with the model of standard 0.6μm 5V CMOS process.关键词：subthreshold circuits;externally-linear internally-nonlinear circuits;analog multiplier0|2|0更新时间：2025-07-02
- 摘要：A new method called center distance ratio which is able to extract support vectors from given training examples is presened for support vector algorithm.The method greatly reduces the training samples and so improves the speed of support vector machine,while the ability of support vector machine to classification is unaffected.Our experimental results show remarkable improvement of speed support vector to support our idea.关键词：support vector machine;center distance ratio method;margin vector;support vector0|2|35更新时间：2025-07-02
- 摘要：This paper presents an overview of recent developments of modern small satellite.According to our experience of the small satellite innovation project,the key technologies of modern small communication satellite are discussed.The question of Doppler frequency shift of communication channel is studied in detail.In the end,we give our prospect and tactic about the development and application of small communication satellite in China.关键词：small satellite;communication satellite constellation;mobile communication0|2|1更新时间：2025-07-02
- 摘要：As one of the most important fusion methods,Dempster-Shafer(DS)method has been used widely in all kinds of data fusion systems.In this paper,the fusion model based on DS method,typical realization approaches of this method,and DS method's extension are discussed comprehensively.Finally,commentaries on this fusion emthod from the viewpoint of data fusion are given,and it is pointed out that combining DS method with other related theories is an important trend.关键词：data fusion;Dempster-Shafer method;uncertainty reasoning0|2|48更新时间：2025-07-02
- 摘要：Rank reduction methods for STAP in existence are all off-line.We are cognizant of that a rank reduction method should be on-line since the clutter is variable with target location.An implementation of adaption for DOF (degree of freedom) in force,called structure adaption for STAP is presented.It is evident that structure adaption can reduce the large computational requirements of STAP that prohibit full-dimensional processing in real-time despite the minor degradation in performance.关键词：airborne phased array radar;STAP;clutter suppression;rank reduction0|2|2更新时间：2025-07-02
- 摘要：Match Fourier transform,a new method of signal processing,is proposed in this paper.It is the development of Fourier transform and the generalization of changing sample rates processing technology.An analysis has been made of match Fourier transform and the relation of it with changing sample rates processing.Finally,the computer simulation result agrees with those of match Fourier transform.关键词：nonstationary signal;LFM;changing sample rates processing;match Fourier transform0|2|31更新时间：2025-07-02
- 摘要：The definition of the Fractional Fourier Transform (FRFT) has been presented in the paper.Several fast algorithms of discrete FRFT have been reviewed.The performances of these algorithms have been analyzed briefly.Based on this analysis,a new algorithm for efficient and accurate computation of FRFT is given.This algorithm needs not to consider the match between eigenvalues and eigenvectors.There are some advantages such as easily understanding and implementing with excellent effect.And if the rotational angle is changed,only a diagonal matrix should be recomputed.A few simulation results for some typical signals are provided to compare with previous ones by other methods in the end.关键词：fractional Fourier transform;hermite function;time-frequency analysis0|2|9更新时间：2025-07-02
- 摘要：In this paper,the theoretical basis of a new calibration method called "nose-to-nose"(NTN) is studied that could be applied to the calibration of broadband sampling oscilloscope,according to the theory of circuitry and signal as well as practical case.After analyzing the generation mechanism of an important signal called kick-out pulse in NTN procedure and getting its expression,the conclusion is gotten that "kick-out pulse is proportional to the step response of the sampling system of oscilloscope",which is our new discovery.Finally,the diode nonlinearity and circuit asymmetry infections as well as the errors due to the method itself are discussed.关键词：nose-to-nose;calibration;sampling oscilloscope;measurement0|2|5更新时间：2025-07-02
- 摘要：In this paper,Standing-Traveling Wave Boundary Condition (STWBC) is developed to truncate the computational domain without reflection.The perfect electric conducting (PEC) termination is used,and unlike the PML,no additional absorbing region surrounding the domain of interest is needed.With STWBC,the standing wave on the boundary is transformed to the traveling wave,and creates no reflections.Numerical examples demonstrate that the FDTD implementation of the STWBC technique is stable,and independent of the incident angle of the outwardly traveling wave.As compared to PML,it allows us to obtain a little lower accuracy but a great release of computational requirements.Thus it is more computationally efficient for a big target.关键词：finite-difference time-domain;standing-traveling wave boundary condition;perfectly matched layer (PML)0|2|0更新时间：2025-07-02
- 摘要：A novel wavelength converter is proposed by use of D-fiber after periodically thermal/electric-field poling in the paper for the first time.The expressions for conversion efficiency η and bandwidth Δλ are derived,which are consistent with numerical calculation.The results show that η is proportional to the logarithm of second-order nonlinear coefficient and pump light power,and,however,they have only a little effect to Δλ.By properly increasing the length of D-fiber η can be efficiently enhanced,but Δλ will be decreased.Under the ordinary condition,η＞-15dB and Δλ＞100nm can be achieved.The wavelength conversion for 8-channel signal is simulated.关键词：WDM;bandwidth;wavelength conversion;poling0|2|0更新时间：2025-07-02
- 摘要：The propagation characteristics of magnetostatic forward volume waves (MSFVWs) for a double-layered YIG waveguide structure under inclined magnetic field are theoretically studied and the secular equation is obtained.In addition,the dispersion relation and delay characteristics of the coupled mode in two different YIG films are studied by numerical analogue in the range of inclination angle from 5° to 20°.The results indicate that the MSFVWs propagating in double-layer YIG structure are appropriate for high frequency range under inclined field,and they have an optimum regulating range of delay rate superior to single film by adjusting the inclination angle of magnetic field.Apparently,the performance of the double-layered waveguide under inclined field has important significance to the application of magnetostatic waves and magneto-optic waveguide devices in the future.关键词：magnetostatic wave;dispersion relation;delay characteristic0|2|0更新时间：2025-07-02
- 摘要：In this paper,a subdomains splicing technique for iterative physical optics (IPO) approach has been presented.It can be applied to calculate the radar cross section (RCS) of electrically large size cavities widely,and reduce the time of numerical computation greatly.The new approach is to split a cavity into some subcavities and to analyze each subcavity with IPO approach.The electromagnetic coupling of each subcavity has been considered by a loop iterative in the whole cavity.Some numerical results have been shown to verify the present approach.关键词：cavity;iterative physical optics;subdomain method;radar cross section0|2|11更新时间：2025-07-02
- 摘要：In this paper we present a novel acquisition scheme based on Faraday anomalous dispersion optical filter (FADOF)'s tunable characteristic for inter-satellite laser communication link.In this way,the typical bandwidth of FADOF was reduced to 0.01nm and the requirements to set up LEO-GEO laser link in any visible position can be accommodated.We also do some elementary experimental research about this scheme.关键词：inter-satellite laser communication;acquisition;faraday anomalous dispersion optical filter (FADOF);tuning0|2|1更新时间：2025-07-02
- 摘要：In the ISAR imaging of maneuvering targets, the time-varying Doppler spectrum must be taken into account to produce a focused image,and above all,motion induced errors,such as envelope alignment errors and auto-focusing phase errors,must be compensated to get a high quality image.In this paper, a signal model is first established in which the motion compensation errors and the feature of the target are both treated as parameters to be estimated,then a parameter constraint is proposed to cope with the uncertainty in the signal model,and finally the resolution ability of the super resolution algorithm in the established signal is analyzed.关键词：super-resolution;ISAR imaging of maneuvering targets;envelope alignment;auto-focus;motion compensation;resolution ability0|2|0更新时间：2025-07-02
- 摘要：Considering the one-sidedness and inaccuracy of knowledge discovery only from single-color database,an approach is proposed to discover knowledge from 1331 groups of mix-color database with partial least-square regression,based on measuring and learning 400 groups of single-color database.By this method,the mean error decreases when converting from RGB to CMYK,the precision of color matching is improved,and the automatic and general problem in color matching is further solved.关键词：color matching;machine learning;knowledge discovery;partial least-square regression1|2|3更新时间：2025-07-02
- 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