最新刊期
卷 36 ， 期 6 ， 2008
- 摘要：For the application of target discrimination in SAR images,a method of feature selection based on Genetic Algorithm (GA) is proposed in this study.First,eight features including four spatial edge property features,one fractal dimension feature and three contrast features,are extracted to distinguish target and clutter false alarm.Then,the GA is applied to select the best feature series from the feature vector consisting of eight features.The fitting function in GA is devised by considering three factors including describing length,the total wrong number of discrimination and losing number.So it can evaluate the feature better than other algorithms.The experimental results of actual data demonstrate the presented algorithm is effective.关键词：synthetic aperture radar;discrimination;feature extraction;feature selection2|1100|8更新时间：2025-07-16
- 摘要：A novel image forensic detection scheme for digitial images was proposed in this paper,which can determine whether an image is tampered or not using blue operation.The difference between artifical blur and defocus blur can be indicaded by edge processing using homostasis filtering and mathematical morphology.The blue tampered regions can be detected by blur edge analysis.Experimental results demonstrate the effectiveness of the proposed scheme.关键词：digital forensics;image processing;mathematical morphology;blur;homostasis filtering2|1760|22更新时间：2025-07-16
- 摘要：2-D super-resolution methods at subarray level possess important significance for multi-function phased array radar.The WSF method at subarray level suitable for coherent source is presented.The application of simplified array manifolds is a quite effective approach to reduce calibration cost and expense of phased array.Therefore,weighting network at subarray level is introduced so that simplified array manifold based on approximate Gaussian patterns is constructed,thereby the flexibility of super-resolution direction finding is improved greatly.This method overcomes the disadvantage of the method based on direct simplified array manifold whose available direction finding area can’t be changed and the sidelobe sources can’t be suppressed completely.Compared with the simplified array manifold based on the Gaussian patterns,cost and complexity of calculation is reduced remarkably and the direction finding performance is basically not degraded at the same time.Simulation results demonstrate the validity of the proposed method.关键词：super-resolution at subarray level;WSF method;simplified array manifold;approximate Gaussian pattern;phased array radar2|888|6更新时间：2025-07-16
- 摘要：By dealing with the raw giant data samples authorized by CAIDA,we obtain one-way link delay.Together with the ratio of the biggest link delay to the end-to-end delay and the distribution of the Internet hops,the dominant delay is defined.Analysis on the impact of link delay on the end-to-end delay reviews that discrepancy of dominant delay primarily accounts for the multi-modal distribution of end-to-end delay.Besides,dominant delay tends to position more preferentially on the middle part of paths and inside the AS,which indicates that the delay bottleneck was shifted from access part to transmission part.At last,conclusion is draw that propagation delay is the major composition of the dominant delay as the effect of transmission delay declined.关键词：Internet measurement;link delay;dominant delay;hops2|1096|6更新时间：2025-07-16
- 摘要：The diffraction of natural radiation is analyzed with GTD theory and the brightness temperature formula is deduced to calculate the diffraction effects.The numerical results indicate that the natural environment and the sun out the direct viewing field only generate ignorable diffraction temperatures of more less than 1K.Without considering diffraction effects the ray tracing method was introduced to the image simulation of natural scene radiation,the emitting model and illuminating model of natural surface are established,the polarization rotation in ray transmission process are also considered.Real scene of building is simulated at last and validated by comparing with field measurement,which indicates that this simulation model is completely feasible in practice.关键词：geometric theory of diffraction (GTD);passive microwave imaging;ray tracing;scene simulation2|792|0更新时间：2025-07-16
- 摘要：The three-dimensional perturbation effect of relativistic electron beam in ion-channel is analyzed by use of the charge fluid linear perturbation theory without extra magnetic field.The equivalent dielectric tensor of the system is derived.Particular research and numerical calculation for propagating axial electromagnetic wave are presented.The dispersion relation of the system is obtained.It is clearly shown that the electromagnetic slow-wave characteristics exist in the system.The electromagnetic radiation may result from the coupling of microwave mode to electronic Betatron motion.Finally,the research result gives a circumstantial evidence that the electromagnetic radiation,which brought from the electromagnetic instability in the system,might be Cherenkov radiation under a certain condition.关键词：ion-channel;dielectric tensor;dispersion relation;slow-wave characteristics2|719|0更新时间：2025-07-16
- 摘要：A noncoherent demodulation method for chirp-rate modulation is proposed based on the fractional Fourier transform,and the peak output of the demodulator is derived. Thereafter,this method is compared with coherent demodulation with matched filter from two aspects of Doppler shift and bit synchronization. And the analytical expressions of influence caused by the two factors are obtained,from which we can see that chirp-rate modulation has strong robustness on Doppler shift but sensitivity of bit synchronization. Finally,the simulations are made to prove the above-mentioned theories,as well as to analyze Bit Error Rate (BER). The performance of this proposed method is worse than coherent demodulation with matched filter for the former’s noncoherent mode,but the difference in BER is 3 dB.关键词：spread spectrum communication;chirp-rate modulation;fractional Fourier transform;matched filter2|1299|6更新时间：2025-07-16
- 摘要：According to receiver’s dynamic environment,high dynamic GPS signal simulator can precisely generate GPS signal that the receiver get.After a thorough analysis of the signal received by the GPS receiver,it is found that in the GPS signal simulator the frequency of the code and carrier and the time delay of the signal spreding are computed at a certain interval according to the receiver time.Since there is a acceleration between the receiver and GPS satellites,the interval of the signal transmit time is not equal to the interval of the signal sampled time.The computation method for the GPS signal in the high dynamic condition is presented.Based on the error analyse of the model,the method with the increasing the sampling rate for minimizing the errors caused by the simulation of the high acceleration signal is proposed.关键词：GPS;high dynamic signal simulator;signal controlling4|1394|1更新时间：2025-07-16
- 摘要：the movement of the terminals in mobile communication which leads to the continuous changing of the DOAs of all signals,the random steering vector errors and the covariance matrix estimation errors result in the degradation of the output SINR with conventional beamformer.As a new robust beamformer,QSP beamformer presents its good performance in that situation depending on its efficiency and validity.The simulations prove the stable output can be maintained in different environment with different impact factor.关键词：beamforming;quantum signal processing;impact factor;array error3|784|0更新时间：2025-07-16
- 摘要：A adaptive thresholding algotithm for motion detection based on two-dimensional spatio-temporal fuzzy entropy principle is proposed.A fast solution for calculating the two-dimensional fuzzy entropy threshold is deduced,in which repeated calculation is avoided by using integral and iterative operation,and the various calculation operation is reduced from O(N4) to less than O(N3) for N gray-level image.The motion detection is reduced to two binary partition problems,and two-dimensional spatio-temporal fuzzy entropy principle is used to determine the threshold T,where the explicit function form or parameters of background distribution are not needed to be known.The experimental results show that the information of moving objects which have low contrast to background can also be extracted completely by this method in real time.关键词：two-dimensional fuzzy entropy principle;motion detection threshold;moving object extraction;integral operation;iterative operation2|733|0更新时间：2025-07-16
- 摘要：In terms of the theoretical analysis,the cross correlation computation formula based on frequency difference coefficient was deduced,and two new cross correlation mitigation methods,called the parallel cross correlation subtraction and the parallel cross correlation subtraction based on frequency difference coefficient were addressed.By the tests in which one to three strong interference signals with the intensity of 16 to 30dB were simulated,the effects of the two cross correlation mitigation methods in high sensitivity GPS receivers were good and the practicality of them was higher.The parallel cross correlation subtraction method based on frequency difference coefficient had much advantage on computation quantity,and was able to accelerate the signal acquiring speed of high sensitivity receivers and make the receivers work well when receiving signals with much weaker intensity and lower signal noise ratio.关键词：communication techniques;cross correlation mitigation;simulation;CDMA(code division multiple access);high sensitivity;GPS(global positioning system) receiver2|1792|9更新时间：2025-07-16
- 摘要：The performance of target detection using long-time integration would be influenced by the migrations of range and doppler frequency.In order to analyze the influence in the external illuminating radar which makes use of TV radio signal,an associated ambiguity function expressed by the time delay,doppler shift,time delay varying rate and chirp rate is defined.Subsequently,the average associated ambiguity function and integration loss of the TV radio signal are both derived.The relationship of the integration loss with the velocity,acceleration and integration time is obtained.And some conclusions are also acquired.This research can provide some theoretical reference for analyzing the performance of target detection in the external illuminating radar.关键词：associated ambiguity function;range migration;Doppler frequency migration;long-time integration2|849|4更新时间：2025-07-16
- 摘要：Spotlight SAR is an effective way to obtain high resolution radar imagery.The effect of the wavefront curvature will defocus the point far away from the imagery center by the classical polar format algorithm.We analyse the mechanism of wavefront curvature and space variant phase error in polar format algorithm,then present an overlapped sub-aperture polar format algorithm of the wavefront curvature correction during the course of SAR imaging,which can increase the imaging area for PFA algorithm and can be used in P band imaging and ultra high resolution imaging.关键词：wavefront curvature correction;polar format algorithm(PFA);overlapped subaperture2|1232|7更新时间：2025-07-16
- 摘要：The errors associated with a segmented primary reflector limit the electrical performance obtainable with those antennas which employ them.It is necessary to derive the effect of panel positional error on electrical performance in order to determine panel adjustments for such reflector antennas.The transformation matrix that relates panel adjustments to surface errors in terms of best fit paraboloid (BFP) is derived.Based on the transformation matrix,a novel mathematical model and a useful program are developed.After being used in practice the results have shown that the method for panel adjustment is of efficiency.关键词：reflector antenna;panel adjustment;best fit paraboloid;electromechanical coupling2|1307|16更新时间：2025-07-16
- 摘要：Iterative formulas of JE convolution finite-difference time-domain(JEC-FDTD) algorithm for 3 dimension anisotropic magnetized plasmas were proposed.It had been Pointed out that the difference of the parallel JEC-FDTD algorithm and the general parallel FDTD algorithm.The current density iteration has been added,and more many datum have been exchanged in the common boundaries.And the parallel program of JEC-FDTD algorithm had been gotten based on the MPI.Parallel JEC-FDTD program was reliable by the example that RCS(radar cross section) of conduct sphere coated plasma had been calculated,and parallel efficiency of parallel program was tested in one cluster.Finally the back RCS of one airplane coated the magnetized plasmas was calculated by the parallel JEC-FDTD.The results indicate that the parallel JEC-FDTD is reliable;its parallel efficiency is high;and it has ability of deal with the scattering characteristics of the electrically large magnetized plasma targets.关键词：parallel;FDTD;magnetized plasma;RCS2|1023|3更新时间：2025-07-16
- 摘要：Recently Koy proposed primal-dual bases which have better quality than LLL-reduced bases in high-dimensional lattice,but his efforts did not take into account the low and upper bounds for the ratios of primal-dual bases to successive minima.In this paper some useful properties of Koy’s primal-dual bases are analyzed and then the low and upper bounds for the ratios of primal-dual bases to successive minima are introduced and proved.At the end,the Round-off algorithm for the approximate-CVP is improved using primal-dual bases and its result has a better approximation factor than L.Babai’s.关键词：lattice;reduced bases;successive minima;length defect;the closest vector problem(CVP)2|805|1更新时间：2025-07-16
- 摘要：This paper presents an experimental system of ElectroMagnetically Induced Thermo-Acoustic (EMITA).Focusing on the signal extraction of EMITA,several treatments are adopted to improve the compatibility of the system under high power electromagnetic pulses.To improve the transition of the microwave energy to the biologic tissue,the cross section of the vessel front to the microwave is designed as bevel;to decrease the electromagnetic impose of ultrasound transducer due to the microwave pulse,the coupling liquid is used after careful study.In order to extract the EMITA signals from low signal-to-noise ratio (SNR) background,wavelet analysis with soft thresholding is used to filter the strong noise.Experimental results indicate the effectiveness of the wavelet analysis in the extraction of EMITA signals.关键词：electromagnetically induced thermo-acoustic (EMITA) system;wavelet analysis;threshold denoising method2|954|1更新时间：2025-07-16
- 摘要：The evaluation of time-domain impedance matrix elements needs to respectively compute the space-time integrals in the field cell and the source cell.Because of temporal basis function’s regionality and its derivative’s uncontinuity(such as the triangle temporal basis function ),the accuracy of space-time integral in the source cell is worse by method of the gauss integral and the error increases when time interval gets narrow.The paper accurately computes time-domain impedance matrix elements by transforming space-time integral of the source cell to 1D time convolution and 1D space analytical integral and further solves time-domain electric field,magnetic field and combined field integral equations by method of marching-on-in-time.Numerical results show that the proposed method insures that the solution of time-domain integral equation using marching-on-in-time method is stable and accurate when the time interval changes in the broad range.关键词：time-domain integral equation(TDIE);marching-on-in-time(MOT);combined field integral equation(CFIE)2|1254|5更新时间：2025-07-16
- 摘要：A model describes both of charge lose and charge multiplication when charge delivering in CCM based on Z transform ,which relates to the architecture of EMCCD and the theory of CCM that using impact ionization to multiply photo-generated charge was proposed here.From transfer function of charge delivering in CCM,the amplitude-frequency response was obtained as well as its numerical values with the typical parameters of a CCM.Numerical values and experimental results show that the higher the charge multiplication ratio in CCM,the better improvement the amplitude-frequency response of CCM gets.关键词：Z transform;CCM;charge multiplication;amplitude-frequency response2|842|2更新时间：2025-07-16
- 摘要：An area-efficient design proposal of a direct digital frequency synthesizer is presented.It adopts the improved hybrid coordinate rotation digital computer (CORDIC) algorithm.By cutting down all of rotational phase decision circuits and multipliers,adjusting rotational phase error,and finishing complicated amplitude amendment with simple shift and addition-subtraction circuits,the proposal can decrease the hardware complexity and reduce the circuit area.The pipeline multilevel loop iteration implementation architecture is adopted for reusing shifting and addition-subtraction components highly.The simulation indicates that the miscellaneous interference of output frequency spectrum is lower than -70dB.And the design has superior speed and resource usage.The VLSI design proposal has been used in a frequency modulation module of the broadband network System on Chip (SoC) platform.关键词：direct digital frequency synthesizer;hybrid CORDIC;area-efficient;multilevel loop iteration2|1386|9更新时间：2025-07-16
- 摘要：Robustness is the key problem in digital watermarking.A robust watermarking method based on JADE algorithm is proposed.In the algorithm,watermark is embedded by iterative blending,which guarantees that the watermark has better invisibility and robustness,then regards mixed image as one observed signal,watermark information as the other observed signal.Finally,blind source separation JADE algorithm is adopted to detect the watermark without precise location.The theoretical analysis and simulation results show that it has stronger robustness.关键词：digital watermarking;independent component analysis;joint approximate diagomalization of eigenmatrixe(JADE) algorithm;iterative blending2|1154|4更新时间：2025-07-16
- 摘要：When PO(Physical Optics)method is used to calculate the scattered field of electrically large objects,the double reflection between two objects should be considered independently.The quadruple integration used to compute the double reflection between two perfect conducting objects modeled by NURBS surfaces was derived by PO approximation.The quadruple Ludwig algorithm was presented to compute the quadruple integration which is the key of the computation of the double reflected field.The example shows that the formula and the integration are both valid.关键词：PO;NURBS;double reflection;the quadruple Ludwig algorithm2|923|0更新时间：2025-07-16
- 摘要：The detection problem of dim signal is studied based on narrowband dual-polarization radar system. Firstly the probability density functions of different signals and a novel detection algorithm are presented through polarization and power accumulation in time .We also derive the analytical expression for the probability of false alarm and show that the new receiver can be made bounded constant false alarm rate (CFAR).Then a solution is showed through proving the same distributions between different coordinates of the statistics by which the radar detection performance can be simplified. Finally,we present simulation results,which show the radar detection performance can be obviously improved. It can be useful to anti-radar stealthy,early warning and space detection or other applications.关键词：dim signal;detection;instantaneous polarization2|842|3更新时间：2025-07-16
- 摘要：A lot of interlaced signals from various radiant point make produce two kinds of false location point when DOA location method is used to passive location for radiant point of netted radar.A new location method is given based on the features of distributed jammers for clearing these false location points.Primary signal sorting processed in jammer and fusion signal sorting and identifying processed in fusion center are used to clear the first false location points.Then multi-location method is given to locate netted radar using the data of signal sorting and identifying.The result of simulation demonstrates that the method for locating netted radar is an effectual location method of passive location.关键词：distributed jammers;netted radar;signal sorting;identify;passive location2|1594|3更新时间：2025-07-16
- 摘要：The MPSTD algorithm is applied to model radiating longitudinal slot in the broad face of rectangular waveguide.Firstly,a method of dividing the total field and the scattering field is proposed based on the characteristic variables of Maxwell’s equations.Also the updating functions of the field in the interface between the subdomains of scattering field and total field has been derived.Secondly,the setting of excitation source is proposed by the idea of fields domain partition,which make the subdomains of incident field、 scattering field and total field contacted availably.So it is convenient to place incident field and pick up scattering field.The resonant length and impedance characteristics of longitudinal slot are analyzed by MPSTD.The numerical results show that the MPSTD algorithm is accurate and efficient to analyze the radiating longitudinal slot in the broad face of rectangular waveguide.关键词：multidomain pseudospectral time-domain(MPSTD)algortihm;longitudinal shunt slot2|854|1更新时间：2025-07-16
- 摘要：Because of the diversity of information types and the complexity of information characteristics,traditionally,the multisource heterogeneous information is described and modeled by the corresponding knew theories,so there is rarely an unified method to fusion them. For several years,researchers have explored the unification of theories enabling the fusion of heterogeneous information and have finally considered random set theory. This paper first classifies available information by qualities (uncertain,vague,imprecise,etc) and then presents common theories that can be used to cope with them. Random set theory is introduced as a possible framework for unification. The reasons why the individual theories can fit in this framework are detailed. Finally,this paper reviews applications of random set theory in information fusion and discusses the possible directions in the future.关键词：multisource information fusion;random set theory;imperfect information;artificial intelligence2|1932|18更新时间：2025-07-16
- 摘要：In allusion to energy of echo from rotor blade is too low to be detected,the paper analyses the time characteristic and frequency characteristic of echo from rotor blade,ground clutter and target clutter based math model of echo from rotor blade and the thought of detection for echo from rotor blade in time domain after the clutter is filtered out in frequency domain is brought forward.In allusion to the actuality of recognition for helicopter,the thought of the confident level of helicopter target recognition is guaranteed by controlling the false alarm rate of detection for echo from rotor blade is put forward and statistical distributing of clutter residual and noise after clutter is filtered out in frequency domain is researched and the detection based sliding window is applied to partition the observation vector into the detection cell and reference cell for clutter to accomplish the CFAR detection for echo from rotor blade.The simulation result indicate that the method of filtering clutter can filter the ground clutter and target clutter effectually to improve the detection SCNR of echo from rotor blade.The detector in time domain for echo from rotor blade can work well when the SNCR is low.关键词：echo from helicopter blade;millimeter wave radar;clutter filtered;CFAR detection2|1005|1更新时间：2025-07-16
- 摘要：A method to prevent leakage from computer’s video information by digital filtering is presented.The constraint conditions for digital filter by bandwidth and readability of character are obtained,and the corresponding digital filter is designed with FIR(Finite Impulse Response).The insertion loss of digital filter fluctuates periodically,composite application of analog and digital filter eliminate that disadvantage.And the measured and simulated results are in good agreement,and some important conclusions are achieved.关键词：video information;anti-leakage;information security;digital filtering2|1122|3更新时间：2025-07-16
- 摘要：A theoretical model is proposed for analyzing and simulating the electromagnetic-field-combined profile of several radiation sources in this paper.The formulae of the electromagnetic-field-combined profile and Poynting Vector have been obtained under the consideration of field pattern and polarization.A typical application of several radiation sources,disturbing the tracking of Anti-radiation missile (ARM) with radar and decoys,has been simulated and simulation results show that ARM may be decoyed to a trapped area through the electromagnetic-field-combined profile if three decoys have been distributed near the radar in an appropriate way.关键词：anti-radiation missile;decoy;field pattern;polarization;decoying effect2|982|3更新时间：2025-07-16
- 摘要：The next generation(4G)wireless network is envisioned as a convergence of different wireless access technologies.A vertical handoff is a handoff between access networks with different wireless technologies.We present a speed sensitive vertical handoff algorithm.No need of the accurate position and speed information of the mobile host,it takes into account the influence of velocity based on the history results of received signal strength measurements.This algorithm can automatically adapt to the mobile host’s velocity and improve handoff efficiency.Simulation results show that the proposed algorithm can achieve better performance compared with conventional handoff decision algorithms.关键词：vertical handoff;horizontal handoff;hysteresis;received signal strength2|925|9更新时间：2025-07-16
- 摘要：This paper investigates the problem of signal reconstruction from nonuniformly sampled signals in the fractional Fourier domain.Firstly,the spectral representations of periodic nonuniformly sampled signal in the fractional Fourier domain and the relationship between the spectral and the nonuniform spectral have been deduced.A spectral reconstruction algorithm is proposed based on the derived relationship.Secondly,the signal reconstruction formula from general nonunfiorm samples in the fractional Fourier domain has been proposed.Lastly,the simulation results are obtained for the periodic nonuniform sampling model.关键词：fractional Fourier transform(FRFT);nonuniform sampling;spectral reconstruction;signal reconstruction5|998|4更新时间：2025-07-16
- 摘要：An iterative subspace method for parameters estimation of Prony model (superimposed exponential signals in noise) in the sense of nonlinear least-squares is presented.With condition meeting in the optimization is both necessary and sufficient,such that the solution is sole and globally optimal.The optimal condition is interpreted in the geometric language of abstract vector spaces.In the foundation,a fully effective iterative algorithm is acquired.Thus,both the understanding for the solution is deepened and the convergence property and effectiveness is greatly improved.Finally,the procedure is illustrated with a simple example,and the result compared with one’s of Pro-ESPRIT method.关键词：nonlinear least-squares estimation;iterative subspace;Prony model4|704|0更新时间：2025-07-16
- 摘要：Moving targets appear seriously degraded with smearing,defocusing and apparent shifts in the azimuth direction in Synthetic aperture radar (SAR)images and give rise to a considerable loss of the target-to-clutter ratio (TCR).This paper proposes a method to detect moving targets in single-channel SAR single look complex (SLC)image based on sub-aperture decomposition technique.The method can suppress the clutter by image subtraction between two sub-aperture images,therefore enhance the TCR.The effectiveness of the method is demonstrated on airborne Convair-580 data and Envisat ASAR data.关键词：Moving targets detection;sub-aperture decomposition;SAR2|1060|3更新时间：2025-07-16
- 摘要：An unequal coefficients interframe predictive split vector quantizer is proposed.This quantizer is used for quantizing the ISF (Immittance Spectral Frequencies) parameters of wideband speech.This quantizer is based on interframe correlation and split vector quantization.In this quantizer,the unequal coefficients interframe prediction is firstly applied on the mean-removed ISF parameters vector to be quantized,and then the ISF residual vector is quantized using split vector quantizer.Experimental results show that this quantization scheme achieves transparent coding at 46bits/frame,and the average spectral distortion is lower than that of AMR-WB (ITU-T-G.722.2) speech coding standard.关键词：speech coding;vector quantization;immittance spectral frequencies;unequal coefficients interframe prediction2|937|1更新时间：2025-07-16
- 摘要：Based on the compact support property of popular DWT filters,a low-memory implementation of DWT called the Stripe-Based DWT(SBWT)is proposed,which produces the same subband coefficients as the global implementation of DWT.Additionally,the production of subband coefficients lends itself to PCT-based image coders in that no intermediate buffering is needed between the SBWT and the coders.When coupled with PCT-based image codec’s and 5-level decomposition with the CDF 9/7 filter bank,the overall memory reductions are 18.4% and 17.9% compared with the line-based DWT (LBWT) and the memory-constrained WT,respectively.关键词：local wavelet transform;low memory implementation;parent-children tree2|811|0更新时间：2025-07-16
- 摘要：We propose that perpendicular baseline in InSAR is an important factor affecting the coherence of image pairs,and demonstrate that the existing formula for coherence calculation is based on ideal signal.Then a formula for calculating the correlation coefficient is deduced in combination with the frequency characteristics of radar signals.Furthermore,the changing relationship between correlation coefficient and perpendicular baseline in case of any slope terrain is illustrated.This approach and its numerical results can be referenced in InSAR baseline designing and performance evaluation.关键词：InSAR;topographic mapping;GMTI;perpendicular baseline;coherence2|1439|4更新时间：2025-07-16
- 摘要：Based on analysis of the signal characteristic of the reference channel and the target echo channel for passive radar,we derive the relations of the coherent accumulation gain formula,the signal-to-noise ratio (SNR) of the reference channel,the effective bandwidth of the signal and the coherent accumulation time,which provides the theoretical base for predicting the detection performance of passive radar.Moreover,some suggestions for the baseline selection of passive radar are presented after the relations between the coherent accumulation gain and the SNR of the reference channel are verified and analyzed.关键词：passive radar;coherent accumulation gain;reference channel;baseline selection2|1290|5更新时间：2025-07-16
- 摘要：In the case of uniform linear array (ULA) system,it is found that the interference eigenvalue asymptotes to the periodically extended version of the interference spatial spectrum.This fact was then employed in estimation on the number of interference degrees of freedom (DoF),i.e.,the number of significant interference eigenvalues,in the presence of various non-ideal effects.The proposed method first employs covariance matrix tapers to obtain the interference covariance function and its corresponding spatial spectrum in non-ideal scenarios.Then the number of interference DoF is estimated according to the periodically extended spectrum.The simulations agree with the estimation results.关键词：interference rejection;covariance matrix tapers (CMT);interference degrees of freedom2|788|0更新时间：2025-07-16
- 摘要：The performance of some adaptive filterbank spectral estimation(AFSE)methods in the symmetric alpha-stable noise environment is studied.Three new AFSE methods based on the fractional lower order statistics(FLOS)(AFSE-FLOS)are presented.These new methods are based on the fractional lower order covariance(FLOC)which are better than the methods based on second order statistics(SOS)and first order statistics(FOS)in the alpha-stable noise.The simulation shows the new methods based on FLOS outperforms their respective methods based on SOS and FOS in the alpha-shable noise while performs similar to their respective methods in the Gaussian noise.关键词：alpha stable distribution;adaptive filterbank spectral estimation method(AFSE);fractional lower order statistics(FLOS)2|890|2更新时间：2025-07-16
- 摘要：The philosophy behind the original particle swarm optimization(PSO)is to learn from individual’s own experience and the best individual’s experience in the whole swarm.Estimation of distribution algorithms(EDAs)generate new solutions from a probability model which characterizes the distribution of the current promising solutions in the search space.A novel discrete particle swarm optimization algorithm based on estimation of distribution(EDPSO)is proposed by reasonably combining the ideas of PSO and EDAs.The proposed algorithm breaks the confine of the original speed and location model,and each particle in the population have comprehensive learning ability.Therefore the proposed algorithm effectively extends the PSO to solve combinatorial optimization problems.Simulation results show that the proposed algorithm has superior performance to other discrete PSOs.关键词：discrete particle swarm optimization;estimation of distribution;bipartite subgraph problem;combinatorial optimization problems2|1740|17更新时间：2025-07-16
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