最新刊期
卷 33 ， 期 9 ， 2005
- 摘要：The security of information hiding is of great importance.A secure paradigm of information hiding which is fulfilled by simulating natural operation is suggested.A scheme to realize this secure paradigm in binary images using scanning operation is proposed and a more efficient practical method is also presented based on morphological theory.The matrix encoding is applied to increase the embedding capacity.关键词：information hiding;secure paradigm;scanning;binary image2|957|2更新时间：2025-07-16
- 摘要：This paper presents a speech-hiding algorithm-Analysis-By-Synthesis Energy Ratio Adjust Algorithm (AERAA) that can be deployed on Global System for Mobile Communications (GSM).The algorithm is based on the technique of Analysis-By-Synthesis (ABS) and can adjust adaptively the strength of the security information component according to public speech.The hiding capacity of the algorithm is 50 bits per second.After a lot of experiments,it is proved that this algorithm has strong robustness to many attacks such as Regular Pulse Excited-Long Term Prediction coding (RPE-LTP coding) on GSM,Adaptive Differential Pulse Code Modulation (ADPCM) compression and most of filters.The average Signal Noise Ratio (SNR) of the middle speech is above 37db,therefore the imperceptibility can be ensured.Moreover the algorithm is based on blind-detection,it is simple and effective.关键词：speech hiding;ABS;energy ratio;RPE-LTP coding2|1067|2更新时间：2025-07-16
- 摘要：To resolve the precise imaging problem of spaceborne Scanned-beam Synthetic Aperture Radar (ScanSAR) with large range cell migration,a novel Equivalent-Squint Extended Chirp Scaling (ES-ECS) algorithm is proposed.The full derivation and the realizing approach of the algorithm are presented with the squinted equivalent range model,which describes the relationship of spaceborne geometrical more precisely than the broadside range model.And the optimum look weighting approach is also introduced to avoid the scalloping effect.Finally,the algorithm is verified by simulations.关键词：equivalent squint;extended chirp scaling algorithm;spaceborne SCANSAR;large range cell migration;look weighting processing2|858|1更新时间：2025-07-16
- 摘要：This paper is concerned with the static problem of associating measurements from three-dimensional (3D) passive sensors.Multidimensional assignment methods and a number of near-optimal modifications have been shown to be very effective for data association.But,numerous candidate association cost evaluations of the methods are rather expensive and the computation time is very high.We present a fast data association algorithm called Datum Line Minimum Cost algorithm,which combines datum line algorithm with modified 3D assignment algorithm.The merits of the algorithm are that it can cut candidate associations very fast and reduce the calculations of association costs.Simulation results show significant computational savings over the standard 3D assignment approach.关键词：passive localization;passive sensor;data association;assignment2|1790|9更新时间：2025-07-16
- 摘要：This paper deals with coherent radar polarimetric adaptive detection of targets in partially-homogeneous Gaussian clutter background with unknown covariance matrix.Based on generalized likelihood ratio test(GLRT),polarimetric adaptive subspace detector(PASD) is derived.The theoretical expressions of PFA and PD for PASD are derived.The proposed detection algorithm ensures the constant false alarm rate (CFAR) in homogeneous and partially-homogeneous clutter background.We resort to simulation to analyse the performance of PGLRT,PAMF,PASD in homogeneous clutter and PASD in partially-homogeneous clutter in different polarimetric cases.关键词：partially-homogeneous;Gaussian;polarimetric;subspace detection2|856|0更新时间：2025-07-16
- 摘要：The existing fragile watermarking algorithms can't recognize whether the modification made to the watermarked image is on the image contents or the embedded watermark or both tampered by attackers.In this paper a fragile watermarking scheme with discrimination of tampers on image or watermark is proposed.The low-frequency compressed image,whose low-frequency wavelet coefficients of 7 Most Significant Bits (MSBs) of original image are nonuniform scalar quantization,is converted into a binary sequence as the watermark is to be embedded.The improved security watermark scrambled by chaotic systems is embedded into the LSB of the image data.During image authentication,the proposed method is able to detect the tampered location and discriminate tampers on Image or watermark from the difference image between the low-frequency compressed image and reconstructed image by watermark.Theoretic analysis and simulation results show that the proposed algorithm may not only provide excellent results of detecting the tampered location,but also indicate whether the modification made to the watermarked image is on the image contents or the embedded watermark or both.关键词：fragile watermark;chaos;scalar quantization;scrambling3|1113|14更新时间：2025-07-16
- 摘要：The fairness is introduced to electronic check system for the first time,and the model of fair electronic check is discussed.A fair electronic check system with reusable refund is presented.In the system,the refund is reusable thanks to the RSA-based partially blind signature,and the anonymity revocation is achieved by employing a passive TTP short for trust third party.The system is efficient and meets all basic security requirements.关键词：cryptography;electronic check;anonymity revocation;partially blind signature2|1350|9更新时间：2025-07-16
- 摘要：A new method for passive radar MTD based on fractional correlation is presented by introducing the fractional correlation into the computation of the cross-ambiguity function (CAF).Compared with the FFT-based computation to CAF,the presented method can scan the target only in certain circular sector instead of the whole ambiguity plane,which may decrease the computational load.In addition,since sampling interval of both the angle and the radial can be chosen arbitrarily in the computation of the CAF,it removes the restriction of original time interval,and may provide the accurate estimation in both time-delay and Doppler shift.Finally,the method is also verified by the simulation examples.关键词：fractional correlation;cross-ambiguity function;passive radar;MTD4|1132|8更新时间：2025-07-16
- 摘要：On the basis of the principle of range-Doppler coupling of linear frequency modulation signal,a new method of radial velocity estimation for high coupling coefficient is presented.Using range information brought by radar waveform switching,the radial velocity is efficiently estimated through a uniform velocity model and a uniform acceleration model established in the method,which solves such problems as range measurement bias modification caused by range-Doppler coupling,data association and optimal Kalman Filter construction in the case of high coupling coefficient.The simulation result of missile defense radar verifies the efficiency.关键词：linear frequency modulation;range-Doppler coupling;radial velocity;waveform switch2|1128|4更新时间：2025-07-16
- 摘要：H.264 encoder complexity is remarkable due to mainly variable block size Motion Estimation (ME) and exhaustive RDO mode decision.In this paper,statistical characteristics of modes among adjacent macroblocks spatially and temporally are first studied using H.264 reference software.Then a fast algorithm is proposed accordingly to reduce the computational load of the mode decision.Candidate modes for current macroblock are first inferred from given coded adjacent macroblocks by adopting motion information and ratios of defined mode sub-sets as inference measures.Then a partial RDO approach is applied to the candidate modes to make target mode selection.The ME is considered as a part of mode decision and no ME is required for particular modes that are eliminated in advance.The exhaustive RDO is invoked only if average distortion of the adjacent macroblocks goes beyond a predefined threshold.Simulation results demonstrate that,for image sequences of both class A and class B,the proposed algorithm can reduce encoder complexity significantly while coding quality is only slightly decreased.关键词：H.264;video coding;mode decision;fast algorithm2|1074|2更新时间：2025-07-16
- 摘要：This paper deals with the problem of estimating the number of sources impinging on an array of sensors along with an arbitrary spatially correlated noise field.Under the assumption that the sources are narrow-band and their temporal correlation is longer than that of noise,a new method to solve this problem is proposed which combines the methods of instrumental variable and unitary transformation.In the proposed method,proper instrumental variables are constructed to suppress the effects of noise on the detection performance,and a useful criterion for detection is derived based on the asymptotical analysis of the orthogonality between signal and noise subspace.Detection performance is illustrated by computer simulation and measured data results with comparisons to the traditional and recently proposed methods.关键词：information theoretic criteria;instrumental variable;unitary transformation;detection and estimation2|1398|6更新时间：2025-07-16
- 摘要：Increase of detection range and fast precision tracking are main difficulties in weak aerial target detection for High Frequency Surface Wave Radar (HFSWR).An Anti-Weak Aerial Targets Tracking (AWATT) system for HFSWR is proposed.It consists mainly of Adaptive Modified Hough Transform (AMHT) track initiator,Double Threshold Fast Joint Probabilistic Data Association (DTF-JPDA) and Indirect Measurement (IM) accuracy-improving part.On the condition of low signal-to-noise ratio (SNR),it solves the problems of earlier warning,fast data association and precision tracking.The experimental results indicate the validity of it in tracking and early warning weak aerial targets.关键词：HFSWR;weak targets;tracking2|1080|7更新时间：2025-07-16
- 摘要：Suffering from the exploitation of the cyclostationary property at only one cycle frequency,the existing SC-SSF algorithm can not reach the best performance.By using the minimum-variance spectral estimate method,a new approach exploiting the cyclostationary property at multiple cycle frequencies is discussed in the paper.Firstly,by using the Jacobi-Anger expansion,the direction matrix can be divided into two parts.Secondly,the transforming matrix can be formed according to the two parts.Thirdly,the minimum-variance spectral estimate method is used to estimate the direction.Simulation results demonstrate the effectiveness and superiority of the new approach over the single-cycle SC-SSF algorithm and the conventional focusing transform algorithm for wide-band singals.关键词：cyclostationarity signals;direction-of-arrival estimation;jacobi-anger expansion2|849|4更新时间：2025-07-16
- 摘要：A topography adaptive filter is proposed to improve the coherence of single look complex (SLC) images obtained from different looking angles for interferometric synthetic aperture radar (InSAR) processing,and to improve the coherence estimation as well.The extraction of the linear phase model of the interferogram via local frequency estimation based on the 2-D Chirp-Z transform makes this filter topographically adaptive both in range and azimuth.Adjusting the filter parameters according to the local topography,the adaptive filter performs better than the fixed bandwidth non-adaptive one designed through flat earth phase estimation.Interferometric data set of Mt.Etna is processed topographicaeey adaptively in range and azimuth,and the results are employed for the comparison of the performances of the proposed and conventional filters.Finally,the linear phase model is also used to improve the coherence estimation by eliminating the topography variation in the estimator.关键词：interferometric synthetic aperture radar (InSAR);linear phase model;Prefiltering;topography adaptive filter;coherence estimation2|1068|4更新时间：2025-07-16
- 摘要：A discrete model is firstly set up for High Resolution Profile of an extended target;then the paper presents the math model of echo signal from an extended target for a Stepped Chirp Radar,and proves the principle of synthesizing a HRRP of an extended target by phase coherent integration.The paper studies the effect of motion status on the synthesized HRRP,derives a equation to calculate the shift of HRRP for motion target,and gives a critical velocity for compensating quadratic phase error for a HRRP of a motion target.At last,the paper presents a computer emulation of synthesizing HRRP and proves the conclusion of the paper.关键词：stepped chirp radar;high range resolution profile;Doppler effect;phase factor2|1002|7更新时间：2025-07-16
- 摘要：A fast algorithm based on the randomized Hough transform is presented in order to detect such dim target with parabolic track under the background of K-distributed sea clutter and thermal noise.This algorithm uses three randomly picked points and one searched discrete angle to extract parabola with arbitrary orientation,and employs the time information carried by the three data points to reduce useless samplings further,which speeds up the algorithm remarkably.A theoretic analysis is presented to analyze the detection performance of the algorithm.The results of performance analysis show the relations among the probability of detection,the probability of false alarm,the thresholds and the number of sampling.Simultaneously,the results also show that the detection performance of Hough transform will become the detection performance limit of randomized Hough transform,when the number of sampling increases to infinity gradually.关键词：randomized Hough transform;parabolic curve;curve detection;dim target4|1113|9更新时间：2025-07-16
- 摘要：The study on image theory and the retrieving algorithm of two-dimensional synthetic aperture microwave radiometer with circular antenna array is presented.Based upon simulated annealing algorithm,we will discuss two solutions of obtaining the ideal thinned array.One solution uses half-circle configuration with very much reduced number of elements and taking an image by rotating the array.The other solution selects element positions around the full circle to provide a roughly uniform coverage in the spatial frequency domain.The results show that both solutions have improved characteristics over the conventional design.For the half-circle case,if the integration time allows,with the rotation of the array and the limited time-shared measurements the number of elements can be further reduced to a great extent.For the full-circle case,the array can be thinned up to the least redundant number,which can never be reached by the most popular Y shaped array configuration under same spatial frequency coverage constraint.关键词：2D synthetic aperture radiometer;thinned array;simulated annealing2|1085|6更新时间：2025-07-16
- 摘要：The basic scattering theory of one port antenna and multiple ports antenna array is illustrated,thus clearly clarify the scattering of antenna.Based on the theory,methods can be got to give the antenna mode scattering and structural mode scattering respectively.The work is meaningful for antenna stealth.关键词：antenna;antenna array;scattering;structural mode scattering;antenna mode scattering;stealth6|1267|7更新时间：2025-07-16
- 摘要：We propose a novel algorithm that can effectively reduce the errors of the harmonic parameters estimates of a periodic signal by counteracting the spectral leakage of the windowing FFT of two sampling data sequences,which stagger about half period.Proposed algorithm can be applied to any window function with central symmetry.Theory analysis and simulation results show that the algorithm can significantly improve the precision of harmonic parameter estimates.关键词：harmonic analysis;Spectral leakage;error analysis;measurement error;synchronous error2|1427|6更新时间：2025-07-16
- 摘要：A high order vector basis function is used for solving three-dimensional time-domain magnetic integral equations (TDMFIE).These basis functions are defined over curvilinear triangular patches and represent the unknown electric current density within each patch using the Lagrange interpolation polynomials.The highlight of these basis functions is that the Lagrange interpolation points are chosen to be the same as the nodes of the Gaussian quadratures.As a result,the tedious evaluation of the space-time integrals in the method-of-moments of the time-domain integral equations is greatly simplified and accelerated.Additionally,the surface of an object to be analyzed can be easily meshed because these basis functions do not require the side of a triangular patch to be entirely shared by another triangular patch,which is very stringent requirement for traditional vector basis functions.These basis functions are implemented with point matching for the solution of TDMFIE.Simulation results are presented to demonstrate the accuracy and efficiency of the solution of TDMFIE by using these high order vector basis functions.关键词：high order method;high order vector basis function;point matching;time-domain magnetic integral equation2|730|1更新时间：2025-07-16
- 摘要：When the method of moment is employed to analyze large slotted waveguide arrays,filling the impedance matrix and solving the matrix equation are very time consuming.In this paper,a load balancing parallel scheme is first presented to accelerate the filling process.Then,a novel preconditioner -SN (slot neighbour) preconditioner is introduced which boosts the advantage of giving adequate consideration to the near field interaction between basis functions when the preconditioning matrix is generated.Numerical results demonstrate the validity and efficiency of the proposed algorithms and show that the SN preconditioned CG (conjugate gradient) can significantly accelerate the solution by an order of magnitude for large slot arrays.关键词：slotted waveguide array;method of moment;parallel computation;preconditioned conjugate gradient method2|714|1更新时间：2025-07-16
- 摘要：L band HEMT amplifiers applied inmobile communications must have low input VSWR,In this paper a graphic method is proposed to map the conjugated matched ΓL to Γs plane to find optimized matching network.To calculate cryocooled LNA's NF a lossy input network model is built and a temperature-dependent NF formula is obtained and verified experimentally.The cryocooled LNA in HTS front end is measured with Noise Temperature ＜30 K,VSWRi ＜1.3 and VSWRo ＜1.8,Gain ＞17dB.关键词：cryocooled LNA;MIC design;amplifier noise characteristics2|1101|0更新时间：2025-07-16
- 摘要：In a realistic radar detection scenario,the disturbance power generated by thermal noise and clutter is unknown.So Gini F proposes a method of estimating the disturbance power and then presents an adaptive successive hypotheses test (SHT) procedure to detect the multiple targets in the same range-azimuth resolution cell of a radar system.However,it is hard to get the threshold for the estimation method.Aiming at the above problem,a new estimation method is put forth and the value of relative threshold is derived.An improved adaptive SHT procedure based on the new estimation method is given.The simulation results show that the improved adaptive SHT procedure has a better detection probability.关键词：monopulse radar;multiple targets;estimation of disturbance power;successive hypotheses test2|752|1更新时间：2025-07-16
- 摘要：A novel temporal object access control model (TRBAC) is proposed based on the role-based access control model (RBAC3).The elements,architecture,temporal inherent mechanism and access control method of TRBAC are discussed respectively.It supports temporal user,temporal role and temporal object and their hierarchy structures,and has the dynamic access control power.It may have applications in such as temporal database and workflow management system.关键词：temporal object;access control;role;time constraint;temporal inherence mechanism2|1026|11更新时间：2025-07-16
- 摘要：The paper proposes a method of off-line handwritten digit recognition based on principal curves.The method uses principal curves and reduction of knowledge to extract the structural features of digits and design a classifier.Principal curves are nonlinear generalizations of principal component analysis.They are smooth self-consistent curves that pass through the "middle" of the distribution.They preferably reflect the structural features of the data.Reduction of knowledge is the efficient tool of obtaining classification rules from a decision table.Firstly principal curves are used to extract the structural features of training data.Secondly the classification features are chosen by analyzing the structural features of principal curves in detail,then we set up the decision table that consists of these classification features.Finally we automatically attain classification rules by attribute and attribute value reduction.The method accords with the recognition habit of human and overcomes the disadvantage of statistical features.The experimental result indicates that the method can effectively improve the recognition rate of off-line handwritten digits,and provides a new approach to the research for off-line handwritten digit recognition.关键词：handwritten digit recognition;principal curve;reduction of knowledge;classification rules2|2308|10更新时间：2025-07-16
- 摘要：With widely applications of digital video,the requirement of video transcoding is very exigent.Video transcoding is defined as the conversion of one coded video format to another and becomes a key technique of digital multimedia network gateway.In this paper,a survey on video transcoding in DCT-domain,including several typical architectures,key techniques and an optimal transcoding strategy,and various existing algorithms to analyze their advantages and disadvantages respectively are presented.An intrablock refreshing architecture for reduced spatial resolution transcoding in DCT domain and a soluton of an optimal transcoding strategy are introduced.Several research aspects in the future are proposed.关键词：video transcoding in DCT domain;rate-distortion;an optimal transcoding strategy;intra-refresh2|1011|2更新时间：2025-07-16
- 摘要：The new research and application of using electromagnetic therapy in bone-rebuilding was surveyed in this paper.Meanwhile,some possible research methods are suggested in three aspects.Firstly,bone is anisotropic EM media.Considering its biological complexity,the difficulty and solving method are shown.Secondly,research topics are proposed in macro experimentation.Finally,some methods and research fields are proposed based on the micro cell and molecule experimentation.关键词：electromagnetic;bone;bone-rebuilding2|1443|0更新时间：2025-07-16
- 摘要：Electromagnetic scattering and radiation characteristic of perfect conductor object composed of arbitrary shaped line,surface and volume is analysed by using integral equation and moment method.The unknown current at line,surface and volume is uniformly represented by RWG basic function.For the arbitrary line-surface,surface-surface junction problem,we give the uniform approach to search basic function and unknown associated with it based on current continuity condition.For the radiation problem,we give the method of setting source and calculating input impedance.The method is validated by the example of analyzing monopole and wide-band patch antenna.关键词：surface integral equation;moment method;basic function;input impedance2|1504|2更新时间：2025-07-16
- 摘要：A dynamic MIMO scattering wireless channel model is proposed,based on the multiple-input-multiple-output (MIMO) scattering wireless channel model and is used to analyze the effect of mobility of the scatterers and transceiver antennas on the spatial correlation and capacity of the MIMO wireless channels.The conclusion is attained,which states that the effect is determined by original positions of transceiver antennas,the velocity as well as environments.The simulation results validate the effects and show that there exists an optimum angular spread that forces spatial correlation,which decreases with increasing antenna spacing and does not consistently decrease with increasing angular spread,to reach minimum.关键词：dynamic;MIMO channels;channel capacity;spatial correlation;multiple-antenna2|1421|2更新时间：2025-07-16
- 摘要：This paper investigates the approaches to ground moving target indication (GMTI) for distributed small satellite SAR systems.In particular,we focus on the processing approaches to resolving the range/Doppler aliasing caused by the small antennas of small SAR systems and the high sidelobes arising from the highly sparse satellite array.The key idea of this paper is to extract the space-time spectra of ground moving targets from the space-time plane by using a space-time adaptive processing (STAP) algorithm.Then conventional SAR imaging processing can be used to fully focus the extracted space-time spectra of ground moving targets.To overcome the "blind velocities" caused by the high sidelobes,an approach is suggested to scan the whole space-time plane with the array steering vector is suggested.关键词：distributed small satellites;synthetic aperture radar;ground moving target indication;space-time adaptive processing2|1002|11更新时间：2025-07-16
- 摘要：HF ground wave radar encounters intense interference and clutter during operation in ocean environment.This paper presents an improved adaptive beamforming algorithm introducing clutter constraints which do not destroy the natural temporal coherence of the first-order ocean clutter after interference suppression and benefit target detection in frequency domain subsequently.Performance of presented algorithm for interference suppression is evaluated using data acquired by OSMAR2000.关键词：HF ground wave radar (HF-GWR);adaptive interference suppression;sub-CPI2|959|0更新时间：2025-07-16
- 摘要：Based on the two dimensional harmonic model,this paper studies the problem of estimating the frequencies of closely spaced complex exponentials in the presence of colored noise,and presents a new estimation approach using the two dimensional decimation technique.By using the capability of decimation in the time domain to increase the frequency intervals,the proposed method first separates the frequencies in the frequency domain,and then gives the exact frequency estimations by using the improved two dimensional matrix pencil method.The proposed method is easy to realize and has successfully improved the performance of the existing two dimensional frequency estimation methods in the case of closely spaced frequencies.Simulations are provided to show its performances.关键词：two-dimensional closely spaced frequencies;colored noise;higher order cumulant;two dimensional decimation;over sampling2|689|3更新时间：2025-07-16
- 摘要：The improvement of the capability to detect moving target with very small radar signature is usually realized by long term accumulation.According to the design principle of conventional PD (Pulse Doppler) radar,target's range migration can't exceed half of the range resolution cell in coherent integration time,which means that the accumulation time is restrained by target's motion.For high range resolution radar or the radar system focusing on the detection of fast moving targets,such a restriction is difficult to satisfy.In this paper,a novel motion compensation method based on keystone transform is presented,which can correct range migration without the exact value of target velocity,and as a result,make the accumulation time free of the restriction due to target motion.关键词：weak target detection;coherent integration;Keystone transform;range migration5|2586|71更新时间：2025-07-16
- 摘要：The GTD model which can accurately describe high frequency electromagnetic back scattering,is introduced into the MUSIC algorithm as its signal model to replace the traditional signal model of the MUSIC algorithm,and the MUSIC algorithm is improved in some extent.The paper presents that,in the eigen-analysis method,we can utilize the orthogonal property between signal and noise subspace.The improved MUSIC algorithm can accurately estimate the type of the scattering centers as well as the position of them,and finally results in good effects.We also simulate the impact of the spatial smoothing preprocessing method on the orthogonal property between signal and noise subspace,and point out that the spatial smoothing preprocessing method can affect the structure of the noise subspace and that of the signal subspace,so the preprocessing method can influence the estimation of the type of the scattering centers,we should modify the final result of the scattering centers' type.关键词：scattering center;GTD model;MUSIC algorithm;eigen subspace2|1442|13更新时间：2025-07-16
- 摘要：Information gain maximization is not sufficient condition but only necessary condition when it is used to distribute the sensor resources.In order to let sufficient condition be satisfied,this paper presents a method based on combining target priority with information gain.Based on information gain obtained by interacting multiple model (IMM),this method utilizes the method of partially order sets (POSET) to obtain the weights of different tasks such as detection,tracking and classifying.Sensor resources are reasonably distributed by combining information gain with the tasks' priority.Simulation results show that compared with the method of information gain maximization,this method is better when it is used to distribute finite sensor resources,and it is a practical method.关键词：sensor management;information gain;target priority;partially order sets (POSET);grid2|1093|20更新时间：2025-07-16
- 摘要：Attention is focused on analysis of waveguide circuits using the ADI-FDTD+GRT method to reduce the computational resources required.First,the conventional Geometry Rearrangement Technique (GRT) is modified for the soft source excitation and whole S-parameters can be obtained by locating the source plane and the reference planes correctly.Not only the dominant boundary reflection can be cancelled but also the computational domain can be reduced by the modified GRT.And then the Alternating-Direction Implicit Finite-Difference Time-Domain (ADI-FDTD) method is combined with the modified GRT.By the ADI-FDTD+GRT method the computational time and domain are saved,respectively.In order to demonstrate the computational accuracy and efficiency of this method,a waveguide with discontinuous structure is simulated as an example.The numerical results of this method are compared with those obtained by the conventional FDTD method and the HFSS.In addition the numerical results and the computational requirements of the different ADI-FDTD+GRT cases are compared with those of the conventional ADI-FDTD method.It is found that this method is accurate and efficient.关键词：finite-difference time-domain (FDTD);alternating-direction implicit (ADI);geometry rearrangement technique (GRT);waveguide2|941|2更新时间：2025-07-16
- 摘要：As studied earlier,Two-Channel Cancellation method provides a good way to remove rebound jamming to SAR.But the estimation of the phase difference of the jamming signal is difficult,because the parameters needed to estimate the phase difference is usually unknowable.An automatic way to estimate the phase difference is provided in this paper.First a minimal power criterion is designed and adopted to estimate the phase.After that,an optimization algorithm was used for its estimation.Finally the performance of the method is verified by simulation result.It proves that our algorithm has good performance.关键词：synthetic aperture radar;electronic countermeasures;golden selection method2|991|8更新时间：2025-07-16
- 摘要：MPI based Parallel FDTD code with different virtual topology forms is developed.The code is run on a PC cluster with high performance to analyze a new type of PBG microstrip filter structure.Taking it as an example,the influence of topology schemes on parallel performance of Parallel FDTD is studied.Finally the best MPI virtual topology for Parallel FDTD is presented.关键词：PC clusters;parallel computation;FDTD;PBG2|1155|6更新时间：2025-07-16
- 摘要：Based on the analysis of traditional antennas and nano-physics,the concept of design of antennas with nano-tube array is proposed here.The intrinsic ballistic transportation of electrons in nano-tube makes it possible for antennas consisting of nano-tube array to radiate with higher efficiency.Meanwhile,because there is no skin effect among nano-tubes,required current distribution can be achieved by arranging nano-tubes in a giving aperture and space,thus the gain of present antenna can be further enhanced.Calculation results indicate that,except for the high efficiency,directivity of nano-tube array is better than traditional microstrip antenna with the same area.Possible feed method of nano-tube array is also discussed.关键词：antenna;antenna efficiency;gain;nano-tube antenna2|991|2更新时间：2025-07-16
- 摘要：Test and measurement has been a bottleneck in researching electrostatic and electromagnetic protection.Aiming at test and measurement of the radiated field by ESD,it is proposed to express the bandwidth of ESD radiated field by effective bandwidths according to energy and dynamic range,and the effective bandwidths of the radiated field by ESD and the effect on bandwidths from rising time have been estimated numerically according to the ESD current waveform stipulated in the IEC61000-4-2.In terms of these analyses,a test & measurement system of the radiated field by ESD has been developed successfully.Its measurement bandwidth is 3.5Hz~1GHz (within ±1.5db),the measurable dynamic range is more than 60dB,and the sensitivity is adjustable.And more,the horizontal and vertical coupling E-field stipulated in the IEC61000-4-2 were measured by the test & measurement system.2|1943|14更新时间：2025-07-16
- 摘要：This paper presents a fast and efficient energy evaluation technique (FAEE) at system level according to frame-based real-time distributed system containing voltage variable processing element.Based on FAEE,a modified task assignment method is proposed.Compared with traditional method,CPU time of the latter is about 2 order of magnitudes of that of FAEE's method while energy saving of both techniques is almost the same.关键词：low energy;variable voltage;fast estimation;CPU time;FAEE2|973|1更新时间：2025-07-16
- 摘要：When the camera moves at high speed with its carrier,the target image will degrade with radiant blurring from the center to the periphery of image due to such factors as image exposure time,lengthwise relative motion between camera and target,and others.This will reduce the effective field of vision,and affect target detection,recognition and follow-up.An image degradation model has been established and the factors affecting radiant image blurring are analyzed on the basis of motion imaging relations,signal integration mechanism of photo-electronic detectors,investigation on consecutive image degradation models of radiant blurring under high speed lengthwise relative motion of camera platform,analysis of degradation of some specific images,and further analysis of the actual dispersion imaging processes.The restoration approach of radiant blurred image based on recursive algorithm is proposed.The radiant degraded image simulated by computerized method is consistent with the actual image,and the restoration algorthm is verfied through the microcomputer,and experimental results show that the proposed algorithm can mitigate radiant blur of high-speed lengthwise relative movement effectively.2|849|6更新时间：2025-07-16
- 摘要：This paper discusses the shortcomings of Dempster's rule,Yager's rule and other rules,and then presents a modified combination rule to deal with consistence or inconsistence evidences obtained from multiple sources.The modified rule adapts AND-operation to combine consistent evidences and reflects the intersection of focal elements,and allocates the conflict probability to very inconsistence focus element according to its average supported degree.Experiments show that the new combination rule is very reliable and rational for all kinds of evidences including highly conflicting evidences.关键词：evidence theory;combination rules;data fusion2|920|3更新时间：2025-07-16
- 摘要：The paper presents a run-time reconfigurable coprocessor designed for Space Solar Telescope (SST).The coprocessor provides a 4bit-width reconfigurable array,which transforms instruction-stream-based computing to data-stream-based and configuration-stream-based computing,and employs a 4-stage instruction pipeline to synchronize coprocessor and processor.The paper also gives an implementation of the coprocessor on Xilinx XC2V3000 and performance on the multiplication and the 1024 point complex Fast Fourier Transform.关键词：reconfigurable;run time reconfigurable;coprocessor;data processing onboard4|988|0更新时间：2025-07-16
- 摘要：An intelligent obstacle avoidance model based on BP neural network is established.Also a novel optimal weights initialization technology is proposed so that the sample sets and initial weights can match perfectly.Consequently,the convergence speed increases evidently.In order to improve the real-time performance,hybrid programming using C and assemble language is adopted.Computer simulation and real test show that the system has a strong ability of learning and good performance of human computer interaction.关键词：mobile robot;obstacle avoidance;neural network;BP algorithm;optimal weights initialization technology2|989|0更新时间：2025-07-16
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Efficient and Scalable Algorithms for All-to-All Personalized Communication on Multidimensional Tori
摘要：All-to-all personalized communication,also known as complete exchange,is at the heart of numerous applications in parallel computing environment,such as FFT and matrix transpose.This paper presents new efficient algorithms for all-to-all personalized communication in ring and multidimensional torus.In this paper,we adopt new network-partitioning technique and communication pattern to improve the performance of all-to-all personalized communication for multidimensional torus-connected multiprocessors,and the number of nodes in each dimension needs not be a power of two and square of some number.The main item of the transmission time of the algorithms reaches the lower bound in theory,which can not be obtained in existing indirect algorithms proposed in the literature.Finally,the algorithms are conceptually simple and easily implemented in hardware.关键词：complete exchange;all-to-all personalized communication;parallel algorithm;Torus(Tori);wormhole routing;collective communication2|886|3更新时间：2025-07-16
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